ses

177Lu-EB-PSMA radioligand therapy with escalating doses in patients with metastatic castration-resistant prostate cancer

Purpose: This study is designed to assess the safety and therapeutic response to 177Lu-EB-PSMA treatment with escalating doses in patients with metastatic castration-resistant prostate cancer (mCRPC). Methods: With institutional review board approval and informed consent, patients were randomly divided into three groups: Group A (n = 10) were treated with 1.18 ± 0.09 GBq/dose of 177Lu-EB-PSMA. Group B (n = 10) were treated with 2.12 ± 0.19 GBq/dose of 177Lu-EB-PSMA. Group C (n = 8) were treated with 3.52 ± 0.58 GBq/dose of 177Lu-EB-PSMA. Eligible patients received up to three cycles of 177Lu-EB-PSMA therapy, at eight-week intervals. Results: Due to disease progression or bone marrow suppression, 4 out of 10, 5 out of 10, and 5 out of 10 patients completed three cycles therapy as planned in Groups A, B, and C, respectively. The prostate-specific antigen (PSA) response was correlated with treatment dose, with PSA disease control rates in Group B (70%) and C (75%) being higher than that in Group A (10%) (P = 0.007), but no correlation between Group B and Group C was found. 68Ga-PSMA PET/CT showed response in all the treatment groups, however, there was no significant difference between the three groups. Hematologic toxicity study found that platelets in Group B and Group C decreased more than those in Group A, and that Grade 4 thrombocytopenia occurred in 2 (25.0%) patients in Group C. No serious nephritic or hepatic side effects were observed. Conclusion: This study demonstrates that 2.12 GBq/dose of 177Lu-EB-PSMA seems to be safe and adequate in tumor treatment. Further investigations with increased number of patients are warranted.




ses

Economic Recovery and Anticorruption in South Africa: Assessing Progress on the Reform Agenda

Invitation Only Research Event

4 December 2019 - 3:00pm to 4:00pm

Chatham House | 10 St James's Square | London | SW1Y 4LE

Event participants

Professor Nick Binedell, Founding Director and Sasol Chair of Strategic Management, Gordon Institute of Business Science (GIBS), University of Pretoria

South Africa has significant economic potential based on its resource endowment, quality human capital and well-developed infrastructure compared to the region. However, the country’s economic growth rate has not topped 2 per cent since 2013, and in 2018, was below 1 per cent. This has put a strain on citizens and communities in a country that still suffers from structural inequality, poverty and high unemployment. Economic recovery and anti-corruption were the central pillars of President Cyril Ramaphosa’s 2019 electoral campaign and he has set an investment target of $100 billion. However, voters and investors alike are demanding faster and more visible progress from the country’s enigmatic leader who has a reputation for caution and calculation.

At this event, Professor Nick Binedell will discuss the progress of and opposition to the president’s economic reform agenda and the opportunities for international investment to support long term inclusive and sustainable growth in South Africa.

Attendance at this event is by invitation only. 

Event attributes

Chatham House Rule

Sahar Eljack

Programme Administrator, Africa Programme
+ 44 (0) 20 7314 3660




ses

Can the New European Commission Deliver on Its Promises to Africa?

4 December 2019

Fergus Kell

Projects Assistant, Africa Programme

Damir Kurtagic

Former Academy Robert Bosch Fellow, Africa Programme
Familiar promises of equal partnership must be backed by bolder action, including an expanded budget, internal reform and a rethink of its approach to trade negotiations.

2019-12-03-Urpilainen.jpg

Jutta Urpilainen, new EU commissioner for international partnerships, at the European Parliament in Brussels in October. Photo: Getty Images.

The new European Commission, headed by Ursula von der Leyen, assumed office on 1 December, and there are early signs that Africa will begin near the top of their foreign policy priorities. Policy towards Africa under the new EU administration is yet to be fully defined, but its contours are already visible in the selection of commissioners and assignment of portfolios.  

Although rumours of a dedicated commissioner for Africa were unfounded, the appointment of Jutta Urpilainen to the new role of commissioner for international partnerships – replacing the former post of development commissioner – is a strong signal of ongoing change in EU development thinking, away from bilateral aid towards trade and investment, including by the private sector. 

This may have significant consequences for the EU’s relationship with Africa. In her mission letter to Urpilainen in September, von der Leyen listed the first objective as a new ‘comprehensive strategy for Africa’. Urpilainen, Finland’s finance minister before being posted to Ethiopia as special representative on mediation, has also described her appointment as an opportunity to move on from traditional measures of aid delivery. 

Ambition or incoherence? 

However, this ambition may be at odds with other EU priorities and practices, notably managing migration and institutions and instruments for governing EU–Africa relations that remain rooted in a ‘traditional’ model of North–South development cooperation rather than equitable partnership.

Another newly created post will see Margaritis Schinas assume the role of vice-president for promoting the European way of life – formerly ‘protecting our European way of life’ before a backlash saw it changed – a reminder that migration will remain high on the EU’s foreign policy agenda. The new high representative for foreign and security policy and chief EU diplomat, Josep Borrell, has highlighted the need for bilateral partnership with countries of origin and transit, mainly in Africa. 

Negotiations also continue to stall on a replacement to the Cotonou Agreement, the 20-year partnership framework between the EU and the African, Caribbean and Pacific (ACP) group of states, which now looks certain to be extended for at least 12 months beyond its expiry in February 2020.

Ambiguities in the EU’s negotiating approach have certainly contributed to the delay: having pushed initially for a separate regional pillar for Africa that would be opened to the North African countries (who are not ACP members) and include a loosely defined role for the African Union, this would later be abandoned in favour of a dual-track process on separate new agreements with the AU and ACP respectively.

The EU also continues to pursue controversial economic partnership agreements under the aegis of Cotonou, despite their increasing appearance of incompatibility with the pathbreaking African Continental Free Trade Area (AfCFTA) – one of the clearest expressions to date of African agency.

The EU has so far attempted to gloss over this incoherence, claiming that EPAs can somehow act as the ‘building blocks’ for Africa-wide economic integration. But tensions are appearing between EU departments and within the commission, with the European External Action Service inclined to prioritize a more strategic continental relationship with the AU, while the Directorate-General for International Cooperation and Development remains committed to the ACP as the conduit for financial support and aid delivery.

And it is unlikely to get away with such incoherence for much longer. Change is now urgent, as numerous countries in sub-Saharan Africa continue to attract the strategic and commercial interests of the EU’s competitors: from established players such as China and potentially in future the UK, which is intent on remodelling its Africa ties post-Brexit, to emerging actors such as Turkey or Russia, which held its first Africa summit in October. 

The need for delivery

If the EU is serious about its rhetoric on equal partnership, it must therefore move beyond convoluted hybrid proposals. Delivering on the Juncker administration’s proposal to increase funding for external action by 30 per cent for 2021–27 would mark an important first step, particularly as this involves streamlining that would see the European Development Fund – the financial instrument for EU-ACP relations – incorporated into the main EU budget.

The new commission should therefore continue to exert pressure on the European Council and European Parliament to adopt this proposal, as negotiations on this financial framework have been repeatedly subject to delay and may not be resolved before the end of the year. 

Beyond this, proactive support for the AfCFTA and for structural transformation more broadly must be prioritized ahead of vague promises for a continent-to-continent free trade agreement, as held out by Juncker in his final State of the Union address in 2018. 

The significance of internal EU reforms for Africa should also not be discounted. The EU’s Common Agricultural Policy, for instance, has placed the African sector at a particular disadvantage and has made it harder to compete even in domestic markets, let alone in the distant EU export markets. EU efforts to stimulate inflows of private investments into the African agricultural sector, abolish import tariffs and offer technical support for African producers to satisfy EU health and safety regulations will be of little use if they are undermined by heavy subsidies across Europe.

Ultimately, changes to job titles alone will be insufficient. The new commission’s rhetoric, while ambitious, differs little from that of the previous decade – Africa has heard the promise of a ‘partnership of equals’ and of ‘shared ownership’ since before the advent of the Joint Africa–EU Strategy in 2007. Now is the time for truly bold steps to implement this vision.




ses

POSTPONED: UN Peacekeeping in Africa: Insights from Successes and Failures of the Past

Research Event

10 March 2020 - 3:00pm to 4:00pm

Chatham House | 10 St James's Square | London | SW1Y 4LE

Event participants

Alan Doss, President, Kofi Annan Foundation
 

With Africa hosting half of the UN peacekeeping missions currently in operation and more than 80 per cent of the UN’s peacekeepers, it is clear that crisis management and conflict resolution on the continent remain key priorities. However, traditional international supporters, notably Canada and the United States, have reduced their financial support for peacekeeping in recent years. Together with frequent reports on peacekeeping abuse, declining support is proving disruptive for the maintenance and predictability of UN missions.

At this event, which will launch the book A Peacekeeper in Africa: Learning from UN Interventions in Other People’s Wars, Alan Doss will reflect on past UN peacekeeping missions in Africa and will consider how lessons learned might help to improve future UN peace operations.

PLEASE NOTE THIS EVENT IS POSTPONED UNTIL FURTHER NOTICE.

Sahar Eljack

Programme Administrator, Africa Programme
+ 44 (0) 20 7314 3660




ses

Phosphoproteomic Approaches to Discover Novel Substrates of Mycobacterial Ser/Thr Protein Kinases [Reviews]

Mycobacterial Ser/Thr protein kinases (STPKs) play a critical role in signal transduction pathways that ultimately determine mycobacterial growth and metabolic adaptation. Identification of key physiological substrates of these protein kinases is, therefore, crucial to better understand how Ser/Thr phosphorylation contributes to mycobacterial environmental adaptation, including response to stress, cell division, and host-pathogen interactions. Various substrate detection methods have been employed with limited success, with direct targets of STPKs remaining elusive. Recently developed mass spectrometry (MS)-based phosphoproteomic approaches have expanded the list of potential STPK substrate identifications, yet further investigation is required to define the most functionally significant phosphosites and their physiological importance. Prior to the application of MS workflows, for instance, GarA was the only known and validated physiological substrate for protein kinase G (PknG) from pathogenic mycobacteria. A subsequent list of at least 28 candidate PknG substrates has since been reported with the use of MS-based analyses. Herein, we integrate and critically review MS-generated datasets available on novel STPK substrates and report new functional and subcellular localization enrichment analyses on novel candidate protein kinase A (PknA), protein kinase B (PknB) and PknG substrates to deduce the possible physiological roles of these kinases. In addition, we assess substrate specificity patterns across different mycobacterial STPKs by analyzing reported sets of phosphopeptides, in order to determine whether novel motifs or consensus regions exist for mycobacterial Ser/Thr phosphorylation sites. This review focuses on MS-based techniques employed for STPK substrate identification in mycobacteria, while highlighting the advantages and challenges of the various applications.




ses

Chemical Genetics of AGC-kinases Reveals Shared Targets of Ypk1, Protein Kinase A and Sch9 [Research]

Protein phosphorylation cascades play a central role in the regulation of cell growth and protein kinases PKA, Sch9 and Ypk1 take center stage in regulating this process in S. cerevisiae. To understand how these kinases co-ordinately regulate cellular functions we compared the phospho-proteome of exponentially growing cells without and with acute chemical inhibition of PKA, Sch9 and Ypk1. Sites hypo-phosphorylated upon PKA and Sch9 inhibition were preferentially located in RRxS/T-motifs suggesting that many are directly phosphorylated by these enzymes. Interestingly, when inhibiting Ypk1 we not only detected several hypo-phosphorylated sites in the previously reported RxRxxS/T-, but also in an RRxS/T-motif. Validation experiments revealed that neutral trehalase Nth1, a known PKA target, is additionally phosphorylated and activated downstream of Ypk1. Signaling through Ypk1 is therefore more closely related to PKA- and Sch9-signaling than previously appreciated and may perform functions previously only attributed to the latter kinases.




ses

Decreased Immunoglobulin G Core Fucosylation, A Player in Antibody-dependent Cell-mediated Cytotoxicity, is Associated with Autoimmune Thyroid Diseases [Research]

Autoimmune thyroid diseases (AITD) are the most common group of autoimmune diseases, associated with lymphocyte infiltration and the production of thyroid autoantibodies, like thyroid peroxidase antibodies (TPOAb), in the thyroid gland. Immunoglobulins and cell-surface receptors are glycoproteins with distinctive glycosylation patterns that play a structural role in maintaining and modulating their functions. We investigated associations of total circulating IgG and peripheral blood mononuclear cells glycosylation with AITD and the influence of genetic background in a case-control study with several independent cohorts and over 3,000 individuals in total. The study revealed an inverse association of IgG core fucosylation with TPOAb and AITD, as well as decreased peripheral blood mononuclear cells antennary α1,2 fucosylation in AITD, but no shared genetic variance between AITD and glycosylation. These data suggest that the decreased level of IgG core fucosylation is a risk factor for AITD that promotes antibody-dependent cell-mediated cytotoxicity previously associated with TPOAb levels.




ses

Repression of sphingosine kinase (SK)-interacting protein (SKIP) in acute myeloid leukemia diminishes SK activity and its re-expression restores SK function [Molecular Bases of Disease]

Previous studies have shown that sphingosine kinase interacting protein (SKIP) inhibits sphingosine kinase (SK) function in fibroblasts. SK phosphorylates sphingosine producing the potent signaling molecule sphingosine-1-phosphate (S1P). SKIP gene (SPHKAP) expression is silenced by hypermethylation of its promoter in acute myeloid leukemia (AML). However, why SKIP activity is silenced in primary AML cells is unclear. Here, we investigated the consequences of SKIP down-regulation in AML primary cells and the effects of SKIP re-expression in leukemic cell lines. Using targeted ultra-HPLC-tandem MS (UPLC-MS/MS), we measured sphingolipids (including S1P and ceramides) in AML and control cells. Primary AML cells had significantly lower SK activity and intracellular S1P concentrations than control cells, and SKIP-transfected leukemia cell lines exhibited increased SK activity. These findings show that SKIP re-expression enhances SK activity in leukemia cells. Furthermore, other bioactive sphingolipids such as ceramide were also down-regulated in primary AML cells. Of note, SKIP re-expression in leukemia cells increased ceramide levels 2-fold, inactivated the key signaling protein extracellular signal-regulated kinase, and increased apoptosis following serum deprivation or chemotherapy. These results indicate that SKIP down-regulation in AML reduces SK activity and ceramide levels, an effect that ultimately inhibits apoptosis in leukemia cells. The findings of our study contrast with previous results indicating that SKIP inhibits SK function in fibroblasts and therefore challenge the notion that SKIP always inhibits SK activity.




ses

The mitochondrial protein PGAM5 suppresses energy consumption in brown adipocytes by repressing expression of uncoupling protein 1 [Metabolism]

Accumulating evidence suggests that brown adipose tissue (BAT) is a potential therapeutic target for managing obesity and related diseases. PGAM family member 5, mitochondrial serine/threonine protein phosphatase (PGAM5), is a protein phosphatase that resides in the mitochondria and regulates many biological processes, including cell death, mitophagy, and immune responses. Because BAT is a mitochondria-rich tissue, we have hypothesized that PGAM5 has a physiological function in BAT. We previously reported that PGAM5-knockout (KO) mice are resistant to severe metabolic stress. Importantly, lipid accumulation is suppressed in PGAM5-KO BAT, even under unstressed conditions, raising the possibility that PGAM5 deficiency stimulates lipid consumption. However, the mechanism underlying this observation is undetermined. Here, using an array of biochemical approaches, including quantitative RT-PCR, immunoblotting, and oxygen consumption assays, we show that PGAM5 negatively regulates energy expenditure in brown adipocytes. We found that PGAM5-KO brown adipocytes have an enhanced oxygen consumption rate and increased expression of uncoupling protein 1 (UCP1), a protein that increases energy consumption in the mitochondria. Mechanistically, we found that PGAM5 phosphatase activity and intramembrane cleavage are required for suppression of UCP1 activity. Furthermore, utilizing a genome-wide siRNA screen in HeLa cells to search for regulators of PGAM5 cleavage, we identified a set of candidate genes, including phosphatidylserine decarboxylase (PISD), which catalyzes the formation of phosphatidylethanolamine at the mitochondrial membrane. Taken together, these results indicate that PGAM5 suppresses mitochondrial energy expenditure by down-regulating UCP1 expression in brown adipocytes and that its phosphatase activity and intramembrane cleavage are required for UCP1 suppression.




ses

AIG1 and ADTRP are endogenous hydrolases of fatty acid esters of hydroxy fatty acids (FAHFAs) in mice [Metabolism]

Fatty acid esters of hydroxy fatty acids (FAHFAs) are a newly discovered class of signaling lipids with anti-inflammatory and anti-diabetic properties. However, the endogenous regulation of FAHFAs remains a pressing but unanswered question. Here, using MS-based FAHFA hydrolysis assays, LC-MS–based lipidomics analyses, and activity-based protein profiling, we found that androgen-induced gene 1 (AIG1) and androgen-dependent TFPI-regulating protein (ADTRP), two threonine hydrolases, control FAHFA levels in vivo in both genetic and pharmacologic mouse models. Tissues from mice lacking ADTRP (Adtrp-KO), or both AIG1 and ADTRP (DKO) had higher concentrations of FAHFAs particularly isomers with the ester bond at the 9th carbon due to decreased FAHFA hydrolysis activity. The levels of other lipid classes were unaltered indicating that AIG1 and ADTRP specifically hydrolyze FAHFAs. Complementing these genetic studies, we also identified a dual AIG1/ADTRP inhibitor, ABD-110207, which is active in vivo. Acute treatment of WT mice with ABD-110207 resulted in elevated FAHFA levels, further supporting the notion that AIG1 and ADTRP activity control endogenous FAHFA levels. However, loss of AIG1/ADTRP did not mimic the changes associated with pharmacologically administered FAHFAs on extent of upregulation of FAHFA levels, glucose tolerance, or insulin sensitivity in mice, indicating that therapeutic strategies should weigh more on FAHFA administration. Together, these findings identify AIG1 and ADTRP as the first endogenous FAHFA hydrolases identified and provide critical genetic and chemical tools for further characterization of these enzymes and endogenous FAHFAs to unravel their physiological functions and roles in health and disease.




ses

Inhibition of the polyamine synthesis enzyme ornithine decarboxylase sensitizes triple-negative breast cancer cells to cytotoxic chemotherapy [Molecular Bases of Disease]

Treatment of patients with triple-negative breast cancer (TNBC) is limited by a lack of effective molecular therapies targeting this disease. Recent studies have identified metabolic alterations in cancer cells that can be targeted to improve responses to standard-of-care chemotherapy regimens. Using MDA-MB-468 and SUM-159PT TNBC cells, along with LC-MS/MS and HPLC metabolomics profiling, we found here that exposure of TNBC cells to the cytotoxic chemotherapy drugs cisplatin and doxorubicin alter arginine and polyamine metabolites. This alteration was because of a reduction in the levels and activity of a rate-limiting polyamine biosynthetic enzyme, ornithine decarboxylase (ODC). Using gene silencing and inhibitor treatments, we determined that the reduction in ODC was mediated by its negative regulator antizyme, targeting ODC to the proteasome for degradation. Treatment with the ODC inhibitor difluoromethylornithine (DFMO) sensitized TNBC cells to chemotherapy, but this was not observed in receptor-positive breast cancer cells. Moreover, TNBC cell lines had greater sensitivity to single-agent DFMO, and ODC levels were elevated in TNBC patient samples. The alterations in polyamine metabolism in response to chemotherapy, as well as DFMO-induced preferential sensitization of TNBC cells to chemotherapy, reported here suggest that ODC may be a targetable metabolic vulnerability in TNBC.




ses

Australians are avoiding cash-only businesses: survey

As internet banking and tap-and-go cards become ubiquitous, Australians are beginning to reject businesses that operate on a cash only basis.




ses

Centrelink apologises for web welfare shutdown

Centrelink clients around Australia are furious over missing payments.




ses

Ricochet uses power of the dark web to help journalists, sources dodge metadata laws

A new internet messaging tool that sidesteps the federal government's metadata collection regime to help journalists protect whistle blowers and assists human rights activists has received a tick of approval from security experts.




ses

Why Hollywood animation powerhouses are resisting the cloud

Despite new performance bottlenecks, the digital animation and visual effects industry is very reluctant to move their productions to the cloud, according to Sydney's Animal Logic.




ses

Malcolm Turnbull promises $50 million reboot for troubled myGov

Takeover of troubled portal by Digital Transformation Office confirmed




ses

Centrelink apologises for new privacy breach

Rookie email error shares hundred of email addresses – twice.




ses

Auditor-general exposes weaknesses in ACT government's IT systems

Electronic sexual health records and the births, deaths and marriages registry have been left exposed.




ses

Australia's Cyber Security Strategy: weaknesses, yes, but we're improving

The online world changes so fast it was always going to be tough to design a four-year strategy.




ses

Public service bosses to be schooled in digital following IT problems

Public service bosses will take lessons aiming to improve their leadership in all things digital.




ses

Webinar: European Democracy in the Last 100 Years: Economic Crises and Political Upheaval

Members Event Webinar

6 May 2020 - 1:00pm to 2:00pm

Event participants

Pepijn Bergsen, Research Fellow, Europe Programme, Chatham House

Dr Sheri Berman, Professor of Political Science, Barnard College

Chair: Hans Kundnani, Senior Research Fellow, Europe Programme, Chatham House

 

In the last 100 years, global economic crises from the Great Depression of the 1930s to the 2008 financial crash have contributed to significant political changes in Europe, often leading to a rise in popularity for extremist parties and politics. As Europe contends with a perceived crisis of democracy - now compounded by the varied responses to the coronavirus outbreak - how should we understand the relationship between externally-driven economic crises, political upheaval and democracy?

The panellists will consider the parallels between the political responses to some of the greatest economic crises Europe has experienced in the last century. Given that economic crises often transcend borders, why does political disruption vary between democracies? What can history tell us about the potential political impact of the unfolding COVID-19-related economic crisis? And will the unprecedented financial interventions by governments across Europe fundamentally change the expectations citizens have of the role government should play in their lives?

This event is based on a recent article in The World Today by Hans Kundnani and Pepijn Bergsen who are both researchers in Chatham House's Europe Programme. 'Crawling from the Wreckage' is the first in a series of articles that look at key themes in European political discourse from the last century. You can read the article here

This event is open to Chatham House Members. Not a member? Find out more.




ses

A Direct Fluorometric Activity Assay for Lipid Kinases and Phosphatases

Jiachen Sun
Apr 27, 2020; 0:jlr.D120000794v1-jlr.D120000794
Methods




ses

Phosphatidylinositol Metabolism, Phospholipases, Lipidomics, and Cancer:In Memoriam of Michael J. O. Wakelam (1955-2020)

Edward A Dennis
Apr 28, 2020; 0:jlr.T120000868v1-jlr.T120000868
Tribute




ses

Myeloid-specific deficiency of pregnane X receptor decreases atherosclerosis in LDL receptor-deficient mice

Yipeng Sui
May 1, 2020; 61:696-706
Research Articles




ses

Lipid-tuned Zinc Transport Activity of Human ZnT8 Protein Correlates with Risk for Type-2 Diabetes [Molecular Bases of Disease]

Zinc is a critical element for insulin storage in the secretory granules of pancreatic beta cells. The islet-specific zinc transporter ZnT8 mediates granular sequestration of zinc ions. A genetic variant of human ZnT8 arising from a single nonsynonymous nucleotide change contributes to increased susceptibility to type-2 diabetes (T2D), but it remains unclear how the high risk variant (Arg-325), which is also a higher frequency (>50%) allele, is correlated with zinc transport activity. Here, we compared the activity of Arg-325 with that of a low risk ZnT8 variant (Trp-325). The Arg-325 variant was found to be more active than the Trp-325 form following induced expression in HEK293 cells. We further examined the functional consequences of changing lipid conditions to mimic the impact of lipid remodeling on ZnT8 activity during insulin granule biogenesis. Purified ZnT8 variants in proteoliposomes exhibited more than 4-fold functional tunability by the anionic phospholipids, lysophosphatidylcholine and cholesterol. Over a broad range of permissive lipid compositions, the Arg-325 variant consistently exhibited accelerated zinc transport kinetics versus the Trp-form. In agreement with the human genetic finding that rare loss-of-function mutations in ZnT8 are associated with reduced T2D risk, our results suggested that the common high risk Arg-325 variant is hyperactive, and thus may be targeted for inhibition to reduce T2D risk in the general populations.




ses

Episode 57 - The Internet of Apple press releases (IoAPR) iPads, red iPhones, black OnePlus phones and Android O

Gather round as three men spend 30 minutes talking about tech. Wait, what do you mean 'no thanks'?! Matt Egan shares the mic with David Price and Henry Burrell to thrash out why Apple deemed a press release adequate to announce the successor to 2014's iPad Air 2. There's also a slick new red iPhone, and a black OnePlus 3T. What's with the limited editions, eh? Or are they even limited? The gang also chat about the developer preview of Android O, out now while Android N is barely months old. Is it too early to say if it'll kick ass, and why do Google and Apple need such long public lead time with new OS builds?  


See acast.com/privacy for privacy and opt-out information.




ses

A Direct Fluorometric Activity Assay for Lipid Kinases and Phosphatases [Methods]

Lipid kinases and phosphatases play key roles in cell signaling and regulation, and are implicated in many human diseases, and are hence thus attractive targets for drug development. Currently, no direct in vitro activity assay is available for these important enzymes, which hampers mechanistic studies as well as high-throughput screening of small molecule modulators. Here we report a highly sensitive and quantitative assay employing a ratiometric fluorescence sensor that directly and specifically monitors the real-time concentration change of a single lipid species. Due Because of to its modular design, the assay system can be applied to a wide variety of lipid kinases and phosphatases, including Class I phosphoinositide 3-kinase (PI3K) and phosphatase and tensin homolog (PTEN). When applied to PI3K, the assay provided the newdetailed mechanistic information about the product inhibition and substrate acyl acyl-chain selectivity of PI3K and allowed enabled rapid evaluation of its small molecule inhibitors. We also used this assay to quantitatively determine the substrate specificity of PTEN, providing new insight into its physiological functionThe assay also quantitatively determined the substrate specificity of PTEN, thereby providing new insight into its physiological function. In summary, we have developed a fluorescence-based real-time assay for PI3K and PTEN that we anticipate could be adapted to measure the activities of other lipid kinases and phosphatases with high sensitivity and accuracy.




ses

Phosphatidylinositol Metabolism, Phospholipases, Lipidomics, and Cancer:In Memoriam of Michael J. O. Wakelam (1955-2020) [Tribute]




ses

COVID 19: Assessing Vulnerabilities and Impacts on Iraq

7 April 2020

Dr Renad Mansour

Senior Research Fellow, Middle East and North Africa Programme; Project Director, Iraq Initiative

Dr Mac Skelton

Director, Institute of Regional and International Studies (IRIS), American University of Iraq, Sulaimani; Visiting Fellow, Middle East Centre, London School of Economics

Dr Abdulameer Mohsin Hussein

President of the Iraq Medical Association
Following 17 years of conflict and fragile state-society relations, the war-torn country is particularly vulnerable to the pandemic.

2020-04-07-Iraq-COVID-spray

Disinfecting shops in Baghdad's Bayaa neighbourhood as a preventive measure against the spread of COVID-19. Photo by AHMAD AL-RUBAYE/AFP via Getty Images.

Iraq is a country already in turmoil, suffering fallout from the major military escalation between the US and Iran, mass protests calling for an end to the post-2003 political system, and a violent government crackdown killing more than 600 and wounding almost 30,000 - all presided over by a fragmented political elite unable to agree upon a new prime minister following Adil abd al-Mehdi’s resignation back in November.

COVID-19 introduces yet another threat to the fragile political order, as the virus exposes Iraq’s ineffective public health system dismantled through decades of conflict, corruption and poor governance.

Iraqi doctors are making every effort to prepare for the worst-case scenario, but they do so with huge structural challenges. The Ministry of Health lacks enough ICU beds, human resources, ventilators, and personal protective equipment (PPE). Bogged down in bureaucracy, the ministry is struggling to process procurements of equipment and medications, and some doctors have made purchases themselves.

But individual efforts can only go so far as many Iraqi doctors are concerned the official numbers of confirmed COVID-19 cases do not reflect the complexity of the situation on the ground.

The ministry relies predominately upon patients self-presenting at designated public hospitals and has only just begun community-based testing in areas of suspected clusters. Reliance on self-presentation requires a level of trust between citizens and state institutions, which is at a historic low. This gap in trust – 17 years in the making – puts Iraq’s COVID-19 response particularly at risk.

Iraq’s myriad vulnerabilities

Certain social and political factors leave Iraq uniquely exposed to the coronavirus. The country’s vulnerability is tied directly to its social, religious and economic interconnections with Iran, an epicenter of the pandemic.

Exchanges between Iran and Iraq are concentrated in two regions, with strong cross-border links between Iraqi and Iranian Kurds in the north-east, and Iraqi and Iranian Shia pilgrims in the south. Cross-border circulation of religious pilgrims is particularly concerning, as they can result in mass ritual gatherings.

The high number of confirmed cases in the southern and northern peripheries of the country puts a spotlight on Iraq's failure in managing healthcare. The post-2003 government has failed to either rebuild a robust centralized healthcare system, or to pave the way for a federalized model.

Caught in an ambiguous middle between a centralized and federalized model, coordination across provinces and hospitals during the coronavirus crisis has neither reflected strong management from Baghdad nor robust ownership at the governorate level.

This problem is part of a wider challenge of managing centre-periphery relations and federalism, which since 2003 has not worked effectively. Baghdad has provided all 18 provinces with instructions on testing and treatment, but only a handful have enough resources to put them into practice. Advanced testing capacity is limited to the five provinces with WHO-approved centers, with the remaining 13 sending swabs to Baghdad.

But the greatest challenge to Iraq’s COVID-19 response is the dramatic deterioration of state-society relations. Studies reveal a profound societal distrust of Iraq’s public healthcare institutions, due to corruption and militarization of medical institutions. Numerous videos have recently circulated of families refusing to turn over sick members - particularly women - to medical teams visiting households with confirmed or suspected cases.

As medical anthropologist Omar Dewachi notes, the ‘moral economy of quarantine’ in Iraq is heavily shaped by a history of war and its impact on the relationship between people and the state. Although local and international media often interpret this reluctance to undergo quarantine as a matter of social or tribal norms, distrusting the state leads many families to refuse quarantine because they believe it resembles a form of arrest.

The management of coronavirus relies upon an overt convergence between medical institutions and security forces as the federal police collaborate with the Ministry of Health to impose curfews and enforce quarantine. This means that, troublingly, the same security establishment which violently cracked down on protesters and civil society activists is now the teeth behind Iraq’s COVID-19 response.

Without trust between society and the political class, civil society organizations and protest movements have directed their organizational structure towards awareness-raising across Iraq. Key religious authorities such as Grand Ayatollah Sistani have called for compliance to the curfew and mobilized charitable institutions.

However, such efforts will not be enough to make up for the lack of governance at the level of the state. In the short-term, Iraq’s medical professionals and institutions are in dire need of technical and financial support. In the long-term, COVID-19 is a lesson that Iraq’s once robust public healthcare system needs serious investment and reform.

COVID-19 may prove to be another catalyst challenging the ‘muddle through’ logic of the Iraqi political elite. International actors have largely been complicit in this logic, directing aid and technical support towards security forces and political allies in the interest of short-term stability, and neglecting institutions which Iraqis rely on for health, education, and well-being.

The response to the crisis requires cooperation and buy-in of a population neglected by 17 years of failed governance. This is a seminal event that may push the country to the brink, exposing and stirring underlying tensions in state-society relations.

This analysis was produced as part of the Iraq Initiative.




ses

Why an Inclusive Circular Economy is Needed to Prepare for Future Global Crises

15 April 2020

Patrick Schröder

Senior Research Fellow, Energy, Environment and Resources Programme
The risks associated with existing production and consumption systems have been harshly exposed amid the current global health crisis but an inclusive circular economy could ensure both short-term and long-term resilience for future challenges.

2020-04-15-Waste-Collection-Peru.jpg

Lima city employees picking up garbage during lockdown measures in Peru amid the COVID-19 crisis. Photo: Getty Images.

The world is currently witnessing how vulnerable existing production and consumption systems are, with the current global health crisis harshly exposing the magnitude of the risks associated with the global economy in its current form, grounded, as it is, in a linear system that uses a ‘take–make–throw away’ approach.

These ‘linear risks’ associated with the existing global supply chain system are extremely high for national economies overly dependent on natural resource extraction and exports of commodities like minerals and metals. Equally vulnerable are countries with large manufacturing sectors of ready-made garments and non-repairable consumer goods for western markets. Furthermore, workers and communities working in these sectors are vulnerable to these changes as a result of disruptive technologies and reduced demand.

In a recently published Chatham House research paper, ‘Promoting a Just Transition to an Inclusive Circular Economy’, we highlight why a circular economy approach presents the world with a solution to old and new global risks – from marine plastic pollution to climate change and resource scarcity.

Taking the long view

So far, action to transition to a circular economy has been slow compared to the current crisis which has mobilized rapid global action. For proponents of transitioning to a circular economy, this requires taking the long view. The pandemic has shown us that global emergencies can fast-forward processes that otherwise might take years, even decades, to play out or reverse achievements which have taken years to accomplish.

In this vein, there are three striking points of convergence between the COVID-19 pandemic and the need to transition to an inclusive circular economy.

Firstly, the current crisis is a stark reminder that the circular economy is not only necessary to ensure long-term resource security but also short-term supplies of important materials. In many cities across the US, the UK and Europe, councils have suspended recycling to focus on essential waste collection services. The UK Recycling Association, for example, has warned about carboard shortages due to disrupted recycling operations with possible shortages for food and medicine packaging on the horizon.

Similarly, in China, most recycling sites were shut during the country’s lockdown presenting implications for global recycling markets with additional concerns that there will be a fibre shortage across Europe and possibly around the world.

Furthermore, worldwide COVID-19 lockdowns are resulting in a resurgence in the use of single-use packaging creating a new wave of plastic waste especially from food deliveries – already seen in China – with illegal waste fly-tipping dramatically increasing in the UK since the lockdown.

In this vein, concerns over the current global health crisis is reversing previous positive trends where many cities had established recycling schemes and companies and consumers had switched to reusable alternatives.

Secondly, the need to improve the working conditions of the people working in the informal circular economy, such as waste pickers and recyclers, is imperative. Many waste materials and recyclables that are being handled and collected may be contaminated as a result of being mixed with medical waste.

Now, more than ever, key workers in waste management, collection and recycling require personal protective equipment and social protection to ensure their safety as well as the continuation of essential waste collection so as not to increase the potential for new risks associated with additional infectious diseases.

In India, almost 450 million workers including construction workers, street vendors and landless agricultural labourers, work in the informal sector. In the current climate, the poorest who are unable to work pose a great risk to the Indian economy which could find itself having to shut down.

Moreover, many informal workers live in make-shift settlements areas such as Asia’s largest slum, Dharavi in Mumbai, where health authorities are now facing serious challenges to contain the spread of the disease. Lack of access to handwashing and sanitation facilities, however, further increase these risks but circular, decentralized solutions could make important contributions to sustainable sanitation, health and improved community resilience.

Thirdly, it is anticipated that in the long term several global supply chains will be radically changed as a result of transformed demand patterns and the increase in circular practices such as urban mining for the recovery and recycling of metals or the reuse and recycling of textile fibres and localized additive manufacturing (e.g. 3D printing).

Many of these supply chains and trade flows have now been already severely disrupted due to the COVID-19 pandemic. For example, the global garment industry has been particularly hard-hit due to the closure of outlets amid falling demand for apparel.

It is important to note, workers at the bottom of these garment supply chains are among the most vulnerable and most affected by the crisis as global fashion brands, for example, have been cancelling orders – in the order of $6 billion in the case of Bangladesh alone. Only after intense negotiations are some brands assuming financial responsibility in the form of compensation wage funds to help suppliers in Myanmar, Cambodia and Bangladesh to pay workers during the ongoing crisis.

In addition, the current pandemic is damaging demand for raw materials thereby affecting mining countries. Demand for Africa’s commodities in China, for example, has declined significantly, with the impact on African economies expected to be serious, with 15 per cent of the world’s copper and 20 per cent of the world’s zinc mines currently going offline

A further threat is expected to come from falling commodity prices as a result of the curtailment of manufacturing activity in China particularly for crude oil, copper, iron ore and other industrial commodities which, in these cases, will have direct impacts on the Australian and Canadian mining sectors.

This is all being compounded by an associated decline in consumer demand worldwide. For example, many South African mining companies – leading producers of metals and minerals – have started closing their mining operations following the government’s announcement of a lockdown in order to prevent the transmission of the virus among miners who often work in confined spaces and in close proximity with one another. As workers are laid off due to COVID-19, there are indications that the mining industry will see fast-tracking towards automated mining operations

All of these linear risks that have been exposed through the COVID-19 pandemic reinforce the need for a just transition to a circular economy. But while the reduction in the consumption of resources is necessary to achieve sustainability, the social impacts on low- and middle- income countries and their workers requires international support mechanisms.

In addition, the current situation also highlights the need to find a new approach to globalized retail chains and a balance between local and global trade based on international cooperation across global value chains rather than implementation of trade protectionist measures.

In this vein, all of the recovery plans from the global COVID-19 pandemic need to be aligned with the principles of an inclusive circular economy in order to ensure both short-term and long-term resilience and preparedness for future challenges and disruptions.  




ses

Quantitative profiling of protein tyrosine kinases in human cancer cell lines by multiplexed parallel reaction monitoring assays [Technology]

Protein tyrosine kinases (PTKs) play key roles in cellular signal transduction, cell cycle regulation, cell division, and cell differentiation. Dysregulation of PTK-activated pathways, often by receptor overexpression, gene amplification, or genetic mutation, is a causal factor underlying numerous cancers. In this study, we have developed a parallel reaction monitoring (PRM)-based assay for quantitative profiling of 83 PTKs. The assay detects 308 proteotypic peptides from 54 receptor tyrosine kinases and 29 nonreceptor tyrosine kinases in a single run. Quantitative comparisons were based on the labeled reference peptide method. We implemented the assay in four cell models: 1) a comparison of proliferating versus epidermal growth factor (EGF)-stimulated A431 cells, 2) a comparison of SW480Null (mutant APC) and SW480APC (APC restored) colon tumor cell lines, and 3) a comparison of 10 colorectal cancer cell lines with different genomic abnormalities, and 4) lung cancer cell lines with either susceptibility (11-18) or acquired resistance (11-18R) to the epidermal growth factor receptor tyrosine kinase inhibitor erlotinib. We observed distinct PTK expression changes that were induced by stimuli, genomic features or drug resistance, which were consistent with previous reports. However, most of the measured expression differences were novel observations. For example, acquired resistance to erlotinib in the 11-18 cell model was associated not only with previously reported upregulation of MET, but also with upregulation of FLK2 and downregulation of LYN and PTK7. Immunoblot analyses and shotgun proteomics data were highly consistent with PRM data. Multiplexed PRM assays provide a targeted, systems-level profiling approach to evaluate cancer-related proteotypes and adaptations. Data are available through Proteome eXchange Accession PXD002706.




ses

Translating Divergent Environmental Stresses into a Common Proteome Response through Hik33 in a Model Cyanobacterium [Research]

The histidine kinase Hik33 plays important roles in mediating cyanobacterial response to divergent types of abiotic stresses including cold, salt, high light (HL), and osmotic stresses. However, how these functions are regulated by Hik33 remains to be addressed. Using a hik33-deficient strain (hik33) of Synechocystis sp. PCC 6803 (Synechocystis) and quantitative proteomics, we found that Hik33 depletion induces differential protein expression highly similar to that induced by divergent types of stresses. This typically includes downregulation of proteins in photosynthesis and carbon assimilation that are necessary for cell propagation, and upregulation of heat shock proteins, chaperons, and proteases that are important for cell survival. This observation indicates that depletion of Hik33 alone mimics divergent types of abiotic stresses, and that Hik33 could be important for preventing abnormal stress response in the normal condition. Moreover, we found the majority of proteins of plasmid origin were significantly upregulated in hik33, though their biological significance remains to be addressed. Together, the systematically characterized Hik33-regulated cyanobacterial proteome, which is largely involved in stress responses, builds the molecular basis for Hik33 as a general regulator of stress responses.




ses

Dysregulation of Exosome Cargo by Mutant Tau Expressed in Human-Induced Pluripotent Stem Cell (iPSC) Neurons Revealed by Proteomics Analyses [Research]

Accumulation and propagation of hyperphosphorylated tau (p-tau) is a common neuropathological hallmark associated with neurodegeneration of Alzheimer's disease (AD), frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), and related tauopathies. Extracellular vesicles, specifically exosomes, have recently been demonstrated to participate in mediating tau propagation in brain. Exosomes produced by human induced pluripotent stem cell (iPSC)-derived neurons expressing mutant Tau (mTau), containing the P301L and V337M Tau mutations of FTDP-17, possess the ability to propagate p-tau pathology after injection into mouse brain.  To gain an understanding of the mTau exosome cargo involved in tau pathogenesis, these pathogenic exosomes were analyzed by proteomics and bioinformatics. The data showed that mTau expression dysregulates the exosome proteome to result in (1) proteins uniquely present only in mTau, and not control exosomes, (2) the absence of proteins in mTau exosomes, uniquely present in control exosomes, and (3) shared proteins which were significantly up-regulated or down-regulated in mTau compared to control exosomes. Notably, mTau exosomes (not control exosomes) contain ANP32A (also known as I1PP2A), an endogenous inhibitor of the PP2A phosphatase which regulates the phosphorylation state of p-tau.  Several of the mTau exosome-specific proteins have been shown to participate in AD mechanisms involving lysosomes, inflammation, secretases, and related processes.  Furthermore, the mTau exosomes lacked a substantial portion of proteins present in control exosomes involved in pathways of localization, vesicle transport, and protein binding functions. The shared proteins present in both mTau and control exosomes represented exosome functions of vesicle-mediated transport, exocytosis, and secretion processes. These data illustrate mTau as a dynamic regulator of the biogenesis of exosomes to result in acquisition, deletion, and up- or down-regulation of protein cargo to result in pathogenic mTau exosomes capable of in vivo propagation of p-tau neuropathology in mouse brain. 




ses

Webinar: Russian Disinformation's Golden Moment: Challenges and Responses in the COVID-19 Era

Invitation Only Research Event

7 May 2020 - 3:00pm to 4:30pm

Event participants

Anneli Ahonen, Head, StratCom East Task Force, European External Action Service
Keir Giles, Senior Consulting Fellow, Russia and Eurasia Programme, Chatham House
Thomas Kent, Adjunct Associate Professor, Harriman Institute, Columbia University; Senior Fellow, the Jamestown Foundation
Chairs:
James Nixey, Programme Director, Russia and Eurasia, Chatham House
Glen Howard, President, The Jamestown Foundation
The COVID-19 pandemic provides the ideal environment for malign influence to thrive as it feeds on fear and a vacuum of authoritative information. What are the current challenges posed by Russian disinformation, and how should Western nations be responding?
 
In this discussion, jointly hosted by the Jamestown Foundation and the Chatham House Russia and Eurasia Programme, the speakers will consider what best practice looks like in safeguarding Western societies against the pernicious effects of disinformation. 
 
This event will be held on the record.

Anna Morgan

Administrator, Ukraine Forum
+44 (0)20 7389 3274




ses

Erratum: FTY720/fingolimod decreases hepatic steatosis and expression of fatty acid synthase in diet-induced nonalcoholic fatty liver disease in mice [Errata]




ses

Quantification of bile acids: a mass spectrometry platform for studying gut microbe connection to metabolic diseases [Research Articles]

Bile acids (BAs) serve multiple biological functions, ranging from the absorption of lipids and fat-soluble vitamins to serving as signaling molecules through the direct activation of dedicated cellular receptors. Synthesized by both host and microbial pathways, BAs are increasingly understood as participating in the regulation of numerous pathways relevant to metabolic diseases, including lipid and glucose metabolism, energy expenditure, and inflammation. Quantitative analyses of BAs in biological matrices can be problematic due to their unusual and diverse physicochemical properties, making optimization of a method that shows good accuracy, precision, efficiency of extraction, and minimized matrix effects across structurally distinct human and murine BAs challenging. Herein we develop and clinically validate a stable-isotope-dilution LC/MS/MS method for the quantitative analysis of numerous primary and secondary BAs in both human and mouse biological matrices. We also utilize this tool to investigate gut microbiota participation in the generation of structurally specific BAs in both humans and mice. We examine circulating levels of specific BAs and in a clinical case-control study of age- and gender-matched type 2 diabetes mellitus (T2DM) versus nondiabetics. BAs whose circulating levels are associated with T2DM include numerous 12α-hydroxyl BAs (taurocholic acid, taurodeoxycholic acid, glycodeoxycholic acid, deoxycholic acid, and 3-ketodeoxycholic acid), while taurohyodeoxycholic acid was negatively associated with diabetes. The LC/MS/MS-based platform described should serve as a robust, high-throughput investigative tool for studying the potential involvement of structurally specific BAs and the gut microbiome on both physiological and disease processes.




ses

Alirocumab, evinacumab, and atorvastatin triple therapy regresses plaque lesions and improves lesion composition in mice [Research Articles]

Atherosclerosis-related CVD causes nearly 20 million deaths annually. Most patients are treated after plaques develop, so therapies must regress existing lesions. Current therapies reduce plaque volume, but targeting all apoB-containing lipoproteins with intensive combinations that include alirocumab or evinacumab, monoclonal antibodies against cholesterol-regulating proprotein convertase subtilisin/kexin type 9 and angiopoietin-like protein 3, may provide more benefit. We investigated the effect of such lipid-lowering interventions on atherosclerosis in APOE*3-Leiden.CETP mice, a well-established model for hyperlipidemia. Mice were fed a Western-type diet for 13 weeks and thereafter matched into a baseline group (euthanized at 13 weeks) and five groups that received diet alone (control) or with treatment [atorvastatin; atorvastatin and alirocumab; atorvastatin and evinacumab; or atorvastatin, alirocumab, and evinacumab (triple therapy)] for 25 weeks. We measured effects on cholesterol levels, plaque composition and morphology, monocyte adherence, and macrophage proliferation. All interventions reduced plasma total cholesterol (37% with atorvastatin to 80% with triple treatment; all P < 0.001). Triple treatment decreased non-HDL-C to 1.0 mmol/l (91% difference from control; P < 0.001). Atorvastatin reduced atherosclerosis progression by 28% versus control (P < 0.001); double treatment completely blocked progression and diminished lesion severity. Triple treatment regressed lesion size versus baseline in the thoracic aorta by 50% and the aortic root by 36% (both P < 0.05 vs. baseline), decreased macrophage accumulation through reduced proliferation, and abated lesion severity. Thus, high-intensive cholesterol-lowering triple treatment targeting all apoB-containing lipoproteins regresses atherosclerotic lesion area and improves lesion composition in mice, making it a promising potential approach for treating atherosclerosis.




ses

Vitamin E does not prevent Western diet-induced NASH progression and increases metabolic flux dysregulation in mice [Research Articles]

Fatty liver involves ectopic lipid accumulation and dysregulated hepatic oxidative metabolism, which can progress to a state of elevated inflammation and fibrosis referred to as nonalcoholic steatohepatitis (NASH). The factors that control progression from simple steatosis to NASH are not fully known. Here, we tested the hypothesis that dietary vitamin E (VitE) supplementation would prevent NASH progression and associated metabolic alterations induced by a Western diet (WD). Hyperphagic melanocortin-4 receptor-deficient (MC4R–/–) mice were fed chow, chow+VitE, WD, or WD+VitE starting at 8 or 20 weeks of age. All groups exhibited extensive hepatic steatosis by the end of the study (28 weeks of age). WD feeding exacerbated liver disease severity without inducing proportional changes in liver triglycerides. Eight weeks of WD accelerated liver pyruvate cycling, and 20 weeks of WD extensively upregulated liver glucose and oxidative metabolism assessed by 2H/13C flux analysis. VitE supplementation failed to reduce the histological features of NASH. Rather, WD+VitE increased the abundance and saturation of liver ceramides and accelerated metabolic flux dysregulation compared with 8 weeks of WD alone. In summary, VitE did not limit NASH pathogenesis in genetically obese mice, but instead increased some indicators of metabolic dysfunction.




ses

Myeloid-specific deficiency of pregnane X receptor decreases atherosclerosis in LDL receptor-deficient mice [Research Articles]

The pregnane X receptor (PXR) is a nuclear receptor that can be activated by numerous drugs and xenobiotic chemicals. PXR thereby functions as a xenobiotic sensor to coordinately regulate host responses to xenobiotics by transcriptionally regulating many genes involved in xenobiotic metabolism. We have previously reported that PXR has pro-atherogenic effects in animal models, but how PXR contributes to atherosclerosis development in different tissues or cell types remains elusive. In this study, we generated an LDL receptor-deficient mouse model with myeloid-specific PXR deficiency (PXRMyeLDLR–/–) to elucidate the role of macrophage PXR signaling in atherogenesis. The myeloid PXR deficiency did not affect metabolic phenotypes and plasma lipid profiles, but PXRMyeLDLR–/– mice had significantly decreased atherosclerosis at both aortic root and brachiocephalic arteries compared with control littermates. Interestingly, the PXR deletion did not affect macrophage adhesion and migration properties, but reduced lipid accumulation and foam cell formation in the macrophages. PXR deficiency also led to decreased expression of the scavenger receptor CD36 and impaired lipid uptake in macrophages of the PXRMyeLDLR–/– mice. Further, RNA-Seq analysis indicated that treatment with a prototypical PXR ligand affects the expression of many atherosclerosis-related genes in macrophages in vitro. These findings reveal a pivotal role of myeloid PXR signaling in atherosclerosis development and suggest that PXR may be a potential therapeutic target in atherosclerosis management.




ses

Hematopoiesis is regulated by cholesterol efflux pathways and lipid rafts: connections with cardiovascular diseases [Thematic Reviews]

Lipid rafts are highly ordered regions of the plasma membrane that are enriched in cholesterol and sphingolipids and play important roles in many cells. In hematopoietic stem and progenitor cells (HSPCs), lipid rafts house receptors critical for normal hematopoiesis. Lipid rafts also can bind and sequester kinases that induce negative feedback pathways to limit proliferative cytokine receptor cycling back to the cell membrane. Modulation of lipid rafts occurs through an array of mechanisms, with optimal cholesterol efflux one of the major regulators. As such, cholesterol homeostasis also regulates hematopoiesis. Increased lipid raft content, which occurs in response to changes in cholesterol efflux in the membrane, can result in prolonged receptor occupancy in the cell membrane and enhanced signaling. In addition, certain diseases, like diabetes, may contribute to lipid raft formation and affect cholesterol retention in rafts. In this review, we explore the role of lipid raft-related mechanisms in hematopoiesis and CVD (specifically, atherosclerosis) and discuss how defective cholesterol efflux pathways in HSPCs contribute to expansion of lipid rafts, thereby promoting myelopoiesis and thrombopoiesis. We also discuss the utility of cholesterol acceptors in contributing to lipid raft regulation and disruption, and highlight the potential to manipulate these pathways for therapeutic gain in CVD as well as other disorders with aberrant hematopoiesis.




ses

Lipid rafts and neurodegeneration: structural and functional roles in physiologic aging and neurodegenerative diseases [Thematic Reviews]

Lipid rafts are small, dynamic membrane areas characterized by the clustering of selected membrane lipids as the result of the spontaneous separation of glycolipids, sphingolipids, and cholesterol in a liquid-ordered phase. The exact dynamics underlying phase separation of membrane lipids in the complex biological membranes are still not fully understood. Nevertheless, alterations in the membrane lipid composition affect the lateral organization of molecules belonging to lipid rafts. Neural lipid rafts are found in brain cells, including neurons, astrocytes, and microglia, and are characterized by a high enrichment of specific lipids depending on the cell type. These lipid rafts seem to organize and determine the function of multiprotein complexes involved in several aspects of signal transduction, thus regulating the homeostasis of the brain. The progressive decline of brain performance along with physiological aging is at least in part associated with alterations in the composition and structure of neural lipid rafts. In addition, neurodegenerative conditions, such as lysosomal storage disorders, multiple sclerosis, and Parkinson’s, Huntington’s, and Alzheimer’s diseases, are frequently characterized by dysregulated lipid metabolism, which in turn affects the structure of lipid rafts. Several events underlying the pathogenesis of these diseases appear to depend on the altered composition of lipid rafts. Thus, the structure and function of lipid rafts play a central role in the pathogenesis of many common neurodegenerative diseases.




ses

Thyroid nodules: diagnostic evaluation based on thyroid cancer risk assessment




ses

ER stress increases store-operated Ca2+ entry (SOCE) and augments basal insulin secretion in pancreatic beta cells [Molecular Bases of Disease]

Type 2 diabetes mellitus (T2DM) is characterized by impaired glucose-stimulated insulin secretion and increased peripheral insulin resistance. Unremitting endoplasmic reticulum (ER) stress can lead to beta-cell apoptosis and has been linked to type 2 diabetes. Although many studies have attempted to link ER stress and T2DM, the specific effects of ER stress on beta-cell function remain incompletely understood. To determine the interrelationship between ER stress and beta-cell function, here we treated insulin-secreting INS-1(832/13) cells or isolated mouse islets with the ER stress–inducer tunicamycin (TM). TM induced ER stress as expected, as evidenced by activation of the unfolded protein response. Beta cells treated with TM also exhibited concomitant alterations in their electrical activity and cytosolic free Ca2+ oscillations. As ER stress is known to reduce ER Ca2+ levels, we tested the hypothesis that the observed increase in Ca2+ oscillations occurred because of reduced ER Ca2+ levels and, in turn, increased store-operated Ca2+ entry. TM-induced cytosolic Ca2+ and membrane electrical oscillations were acutely inhibited by YM58483, which blocks store-operated Ca2+ channels. Significantly, TM-treated cells secreted increased insulin under conditions normally associated with only minimal release, e.g. 5 mm glucose, and YM58483 blocked this secretion. Taken together, these results support a critical role for ER Ca2+ depletion–activated Ca2+ current in mediating Ca2+-induced insulin secretion in response to ER stress.




ses

Detailed analyses of the crucial functions of Zn transporter proteins in alkaline phosphatase activation [Enzymology]

Numerous zinc ectoenzymes are metalated by zinc and activated in the compartments of the early secretory pathway before reaching their destination. Zn transporter (ZNT) proteins located in these compartments are essential for ectoenzyme activation. We have previously reported that ZNT proteins, specifically ZNT5–ZNT6 heterodimers and ZNT7 homodimers, play critical roles in the activation of zinc ectoenzymes, such as alkaline phosphatases (ALPs), by mobilizing cytosolic zinc into these compartments. However, this process remains incompletely understood. Here, using genetically-engineered chicken DT40 cells, we first determined that Zrt/Irt-like protein (ZIP) transporters that are localized to the compartments of the early secretory pathway play only a minor role in the ALP activation process. These transporters included ZIP7, ZIP9, and ZIP13, performing pivotal functions in maintaining cellular homeostasis by effluxing zinc out of the compartments. Next, using purified ALP proteins, we showed that zinc metalation on ALP produced in DT40 cells lacking ZNT5–ZNT6 heterodimers and ZNT7 homodimers is impaired. Finally, by genetically disrupting both ZNT5 and ZNT7 in human HAP1 cells, we directly demonstrated that the tissue-nonspecific ALP-activating functions of both ZNT complexes are conserved in human cells. Furthermore, using mutant HAP1 cells, we uncovered a previously-unrecognized and unique spatial regulation of ZNT5–ZNT6 heterodimer formation, wherein ZNT5 recruits ZNT6 to the Golgi apparatus to form the heterodimeric complex. These findings fill in major gaps in our understanding of the molecular mechanisms underlying zinc ectoenzyme activation in the compartments of the early secretory pathway.




ses

ADAM10 and ADAM17 proteases mediate proinflammatory cytokine-induced and constitutive cleavage of endomucin from the endothelial surface [Membrane Biology]

Contact between inflammatory cells and endothelial cells (ECs) is a crucial step in vascular inflammation. Recently, we demonstrated that the cell-surface level of endomucin (EMCN), a heavily O-glycosylated single-transmembrane sialomucin, interferes with the interactions between inflammatory cells and ECs. We have also shown that, in response to an inflammatory stimulus, EMCN is cleared from the cell surface by an unknown mechanism. In this study, using adenovirus-mediated overexpression of a tagged EMCN in human umbilical vein ECs, we found that treatment with tumor necrosis factor α (TNF-α) or the strong oxidant pervanadate leads to loss of cell-surface EMCN and increases the levels of the C-terminal fragment of EMCN 3- to 4-fold. Furthermore, treatment with the broad-spectrum matrix metalloproteinase inhibitor batimastat (BB94) or inhibition of ADAM metallopeptidase domain 10 (ADAM10) and ADAM17 with two small-molecule inhibitors, GW280264X and GI254023X, or with siRNA significantly reduced basal and TNFα-induced cell-surface EMCN cleavage. Release of the C-terminal fragment of EMCN by TNF-α treatment was blocked by chemical inhibition of ADAM10 alone or in combination with ADAM17. These results indicate that cell-surface EMCN undergoes constitutive cleavage and that TNF-α treatment dramatically increases this cleavage, which is mediated predominantly by ADAM10 and ADAM17. As endothelial cell-surface EMCN attenuates leukocyte–EC interactions during inflammation, we propose that EMCN is a potential therapeutic target to manage vascular inflammation.




ses

Hyperuricemia Predisposes to the Onset of Diabetes via Promoting Pancreatic {beta}-Cell Death in Uricase Deficiency Male Mice

Clinical studies have shown a link between hyperuricemia (HU) and diabetes, while the exact effect of soluble serum urate on glucose metabolism remains elusive. This study aims to characterize the glucose metabolic phenotypes and investigate the underlying molecular mechanisms using a novel spontaneous HU mouse model in which the Uricase (Uox) gene is absent. In an attempt to study the role of HU in glycometabolism, we implemented external stimulation on Uox-knockout (KO) and wild-type (WT) males with a high-fat diet (HFD) and/or injections of multiple low-dose streptozotocin (MLD-STZ) to provoke the potential role of urate. Notably, while Uox-KO mice developed glucose intolerance in the basal condition, no mice spontaneously developed diabetes, even with aging. HFD-fed Uox-KO mice manifested similar insulin sensitivity compared with WT controls. HU augmented the existing glycometabolism abnormality induced by MLD-STZ and eventually led to diabetes, as evidenced by the increased random glucose. Reduced β-cell masses and increased terminal deoxynucleotidyl TUNEL-positive β-cells suggested that HU-mediated diabetes was cell death dependent. However, urate-lowering treatment (ULT) cannot ameliorate the diabetes incidence or reverse β-cell apoptosis with significance. ULT displayed a significant therapeutic effect of HU-crystal– associated kidney injury and tubulointerstitial damage in diabetes. Moreover, we present transcriptomic analysis of isolated islets, using Uox-KO versus WT mice and streptozotocin-induced diabetic WT (STZ-WT) versus diabetic Uox-KO (STZ-KO) mice. Shared differentially expressed genes of HU primacy revealed Stk17β is a possible target gene in HU-related β-cell death. Together, this study suggests that HU accelerates but does not cause diabetes by inhibiting islet β-cell survival.




ses

Central {alpha}-Klotho Suppresses NPY/AgRP Neuron Activity and Regulates Metabolism in Mice

α-Klotho is a circulating factor with well-documented anti-aging properties; however, the central role of α-klotho in metabolism remains largely unexplored. The current study investigated the potential role of central α-klotho to modulate NPY/AgRP neurons, energy balance, and glucose homeostasis. Intracerebroventricular (ICV) administration of α-klotho suppressed food intake, improved glucose profiles, and reduced body weight in mouse models of Type I and II diabetes. Furthermore, central α-klotho inhibition via an anti-α-klotho antibody impaired glucose tolerance. Ex vivo patch clamp electrophysiology and immunohistochemical analysis revealed that α-klotho suppresses NPY/AgRP neuron activity, at least in part, by enhancing mIPSC’s. Experiments in hypothalamic GT1-7 cells observed α-klotho induces phosphorylation of AKTser473, ERKthr202/tyr204, and FOXO1ser256, as well as blunts AgRP gene transcription. Mechanistically, fibroblast growth factor 1 (FGFR1) inhibition abolished the downstream signaling of α-klotho, negated its ability to modulate NPY/AgRP neurons, and blunted its therapeutic effects. PI3 kinase inhibition also abolished α-klotho’s ability to suppress food intake and improve glucose clearance. These results indicate a prominent role of hypothalamic α-klotho/FGFR1/PI3K signaling in the modulation of NPY/AgRP neuron activity and maintenance of energy homeostasis, thus providing new insight into the pathophysiology of metabolic disease.




ses

Acute Hyperglycemia Increases Brain Pregenual Anterior Cingulate Cortex Glutamate Concentrations in Type 1 Diabetes Mellitus

The brain mechanisms underlying the association of hyperglycemia with depressive symptoms are unknown. We hypothesized that disrupted glutamate metabolism in pregenual anterior cingulate cortex (ACC) in type 1 diabetes (T1D) without depression affects emotional processing. Using proton magnetic resonance spectroscopy (MRS), we measured glutamate concentrations in ACC and occipital cortex (OCC) in 13 T1D without major depression (HbA1c=7.1±0.7% [54±7mmol/mol]) and 11 healthy non-diabetic controls (HbA1c=5.5±0.2% [37±3mmol/mol]) during fasting euglycemia (EU) followed by a 60-minute +5.5mmol/l hyperglycemic clamp (HG). Intrinsic neuronal activity was assessed using resting-state blood oxygen level dependent functional MRI to measure the fractional amplitude of low frequency fluctuations in slow-band 4 (fALFF4). Emotional processing and depressive symptoms were assessed using emotional tasks (Emotional-Stroop, Self-Referent-Encoding-Task SRET) and clinical ratings (HAM-D, SCL-90-R), respectively. During HG, ACC glutamate increased (1.2mmol/kg, +10%, p=0.014) while ACC fALFF4 was unchanged (-0.007, -2%, p=0.449) in T1D; in contrast, glutamate was unchanged (-0.2mmol/kg, -2%, p=0.578) while fALFF4 decreased (-0.05, -13%, p=0.002) in controls. OCC glutamate and fALFF4 were unchanged in both groups. T1D had longer SRET negative-word response-times (p=0.017) and higher depression-rating scores (HAM-D p=0.020; SCL-90-R-depression p=0.008). Higher glutamate change tended to associate with longer Emotional-Stroop response-times in T1D only. Brain glutamate must be tightly controlled during hyperglycemia due to the risk for neurotoxicity with excessive levels. Results suggest that ACC glutamate control mechanisms are disrupted in T1D, which affects glutamatergic neurotransmission related to emotional or cognitive processing. Increased prefrontal glutamate during acute hyperglycemic episodes could explain our previous findings of associations between chronic hyperglycemia, cortical thinning and depressive symptoms in T1D.




ses

Empagliflozin Ameliorates Obesity-Related Cardiac Dysfunction by Regulating Sestrin2-Mediated AMPK-mTOR Signaling and Redox Homeostasis in High-Fat Induced Obese Mice

Sodium glucose co-transporter-2 inhibitors (SGLT2i) have favorable cardiovascular outcomes in diabetic patients. However, whether SGLT2i can improve obesity-related cardiac dysfunction is unknown. Sestrin2 is a novel stress-inducible protein that regulates AMPK-mTOR and suppresses oxidative damage. The aim of this study was to determine whether empagliflozin (EMPA) improves obesity-related cardiac dysfunction via regulating Sestrin2-mediated pathways in diet-induced obesity. C57BL/6J mice and Sestrin2 knockout mice were fed a high-fat diet (HFD) for 12 weeks and then treated with or without EMPA (10 mg/kg) for 8 weeks. Treating HFD-fed C57BL/6J mice with EMPA reduced body weight, whole-body fat, and improved metabolic disorders. Furthermore, EMPA improved myocardial hypertrophy/fibrosis and cardiac function, and reduced cardiac fat accumulation and mitochondria injury. Additionally, EMPA significantly augmented Sestrin2 levels, increased AMPK and eNOS phosphorylation, but inhibited Akt and mTOR phosphorylation. These beneficial effects were partially attenuated in HFD-fed Sestrin2 knockout mice. Intriguingly, EMPA treatment enhanced the Nrf2/HO-1-mediated oxidative stress response, suggesting antioxidant and anti-inflammatory activity. Thus, EMPA improved obesity-related cardiac dysfunction via regulating Sestrin2-mediated AMPK-mTOR signaling and maintaining redox homeostasis. These findings provide a novel mechanism for the cardiovascular protection of SGLT2i in obesity.




ses

Cardiac Magnetic Resonance Myocardial Feature Tracking for Optimized Risk Assessment after Acute Myocardial Infarction in Patients with Type 2 Diabetes

Type 2 diabetes mellitus predicts outcome following acute myocardial infarction (AMI). Since underlying mechanics are incompletely understood, we investigated left ventricular (LV) and atrial (LA) pathophysiological changes and their prognostic implications using cardiovascular magnetic resonance (CMR). Consecutive patients (n=1147, n=265 diabetic; n=882 non-diabetic) underwent CMR 3 days after AMI. Analyses included LV ejection fraction (LVEF), global longitudinal, circumferential and radial strains (GLS, GCS and GRS), LA reservoir, conduit and booster pump strains, as well as infarct size, edema and microvascular obstruction. Predefined endpoints were major adverse cardiovascular events (MACE) within 12 months. Diabetic patients had impaired LA reservoir (19.8 vs. 21.2%, p<0.01) and conduit strains (7.6 vs. 9.0%, p<0.01) but not ventricular function or myocardial damage. They were at higher risk of MACE than non-diabetic patients (10.2% vs. 5.8%, p<0.01) with most MACE occurring in patients with LVEF≥35%. Whilst LVEF (p=0.045) and atrial reservoir strain (p=0.024) were independent predictors of MACE in non-diabetic patients, GLS was in diabetic patients (p=0.010). Considering patients with diabetes and LVEF≥35% (n=237), GLS and LA reservoir strain below median were significantly associated with MACE. In conclusion, in patients with diabetes, LA and LV longitudinal strain permit optimized risk assessment early after reperfused AMI with incremental prognostic value over and above LVEF.