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The plasma lecithin:cholesterol acyltransferase reaction

John A. Glomset
Mar 1, 1968; 9:155-167
Reviews




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Reactive dicarbonyl compounds cause Calcitonin Gene-Related Peptide release and synergize with inflammatory conditions in mouse skin and peritoneum [Molecular Bases of Disease]

The plasmas of diabetic or uremic patients and of those receiving peritoneal dialysis treatment have increased levels of the glucose-derived dicarbonyl metabolites like methylglyoxal (MGO), glyoxal (GO), and 3-deoxyglucosone (3-DG). The elevated dicarbonyl levels can contribute to the development of painful neuropathies. Here, we used stimulated immunoreactive Calcitonin Gene–Related Peptide (iCGRP) release as a measure of nociceptor activation, and we found that each dicarbonyl metabolite induces a concentration-, TRPA1-, and Ca2+-dependent iCGRP release. MGO, GO, and 3-DG were about equally potent in the millimolar range. We hypothesized that another dicarbonyl, 3,4-dideoxyglucosone-3-ene (3,4-DGE), which is present in peritoneal dialysis (PD) solutions after heat sterilization, activates nociceptors. We also showed that at body temperatures 3,4-DGE is formed from 3-DG and that concentrations of 3,4-DGE in the micromolar range effectively induced iCGRP release from isolated murine skin. In a novel preparation of the isolated parietal peritoneum PD fluid or 3,4-DGE alone, at concentrations found in PD solutions, stimulated iCGRP release. We also tested whether inflammatory tissue conditions synergize with dicarbonyls to induce iCGRP release from isolated skin. Application of MGO together with bradykinin or prostaglandin E2 resulted in an overadditive effect on iCGRP release, whereas MGO applied at a pH of 5.2 resulted in reduced release, probably due to an MGO-mediated inhibition of transient receptor potential (TRP) V1 receptors. These results indicate that several reactive dicarbonyls activate nociceptors and potentiate inflammatory mediators. Our findings underline the roles of dicarbonyls and TRPA1 receptors in causing pain during diabetes or renal disease.




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CBD News: Statement by Mr. Ahmed Djoghlaf, CBD Executive Secretary, on the occasion of the Pre-COP10-MOP5 Citizen Forum - Social Sustainability and Biological Safety Policy Reactions & Public Participation, Nagoya, Japan, 9 October 2010.




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Glucocerebrosidases catalyze a transgalactosylation reaction that yields a newly-identified brain sterol metabolite, galactosylated cholesterol [Glycobiology and Extracellular Matrices]

β-Glucocerebrosidase (GBA) hydrolyzes glucosylceramide (GlcCer) to generate ceramide. Previously, we demonstrated that lysosomal GBA1 and nonlysosomal GBA2 possess not only GlcCer hydrolase activity, but also transglucosylation activity to transfer the glucose residue from GlcCer to cholesterol to form β-cholesterylglucoside (β-GlcChol) in vitro. β-GlcChol is a member of sterylglycosides present in diverse species. How GBA1 and GBA2 mediate β-GlcChol metabolism in the brain is unknown. Here, we purified and characterized sterylglycosides from rodent and fish brains. Although glucose is thought to be the sole carbohydrate component of sterylglycosides in vertebrates, structural analysis of rat brain sterylglycosides revealed the presence of galactosylated cholesterol (β-GalChol), in addition to β-GlcChol. Analyses of brain tissues from GBA2-deficient mice and GBA1- and/or GBA2-deficient Japanese rice fish (Oryzias latipes) revealed that GBA1 and GBA2 are responsible for β-GlcChol degradation and formation, respectively, and that both GBA1 and GBA2 are responsible for β-GalChol formation. Liquid chromatography–tandem MS revealed that β-GlcChol and β-GalChol are present throughout development from embryo to adult in the mouse brain. We found that β-GalChol expression depends on galactosylceramide (GalCer), and developmental onset of β-GalChol biosynthesis appeared to be during myelination. We also found that β-GlcChol and β-GalChol are secreted from neurons and glial cells in association with exosomes. In vitro enzyme assays confirmed that GBA1 and GBA2 have transgalactosylation activity to transfer the galactose residue from GalCer to cholesterol to form β-GalChol. This is the first report of the existence of β-GalChol in vertebrates and how β-GlcChol and β-GalChol are formed in the brain.




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Research from Columbia Business School Suggests Hypersensitivity to Coronavirus News Is Driving Market Reactions – and Vice Versa

Friday, April 10, 2020 - 22:45

NEW YORK – On March 11th, the Dow Jones Industrial Average plunged 1,485 points, ending the longest bull-market run in history, and sending the market into nosedive the likes of which has not been witnessed since the Great Recession. While it could take years to fully understand all of the factors that led to this recent crash, a consensus has emerged that fear of an economic downturn brought on by the coronavirus has played a large role.




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Glucocerebrosidases catalyze a transgalactosylation reaction that yields a newly-identified brain sterol metabolite, galactosylated cholesterol [Glycobiology and Extracellular Matrices]

β-Glucocerebrosidase (GBA) hydrolyzes glucosylceramide (GlcCer) to generate ceramide. Previously, we demonstrated that lysosomal GBA1 and nonlysosomal GBA2 possess not only GlcCer hydrolase activity, but also transglucosylation activity to transfer the glucose residue from GlcCer to cholesterol to form β-cholesterylglucoside (β-GlcChol) in vitro. β-GlcChol is a member of sterylglycosides present in diverse species. How GBA1 and GBA2 mediate β-GlcChol metabolism in the brain is unknown. Here, we purified and characterized sterylglycosides from rodent and fish brains. Although glucose is thought to be the sole carbohydrate component of sterylglycosides in vertebrates, structural analysis of rat brain sterylglycosides revealed the presence of galactosylated cholesterol (β-GalChol), in addition to β-GlcChol. Analyses of brain tissues from GBA2-deficient mice and GBA1- and/or GBA2-deficient Japanese rice fish (Oryzias latipes) revealed that GBA1 and GBA2 are responsible for β-GlcChol degradation and formation, respectively, and that both GBA1 and GBA2 are responsible for β-GalChol formation. Liquid chromatography–tandem MS revealed that β-GlcChol and β-GalChol are present throughout development from embryo to adult in the mouse brain. We found that β-GalChol expression depends on galactosylceramide (GalCer), and developmental onset of β-GalChol biosynthesis appeared to be during myelination. We also found that β-GlcChol and β-GalChol are secreted from neurons and glial cells in association with exosomes. In vitro enzyme assays confirmed that GBA1 and GBA2 have transgalactosylation activity to transfer the galactose residue from GalCer to cholesterol to form β-GalChol. This is the first report of the existence of β-GalChol in vertebrates and how β-GlcChol and β-GalChol are formed in the brain.




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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.




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A nematode sterol C4{alpha}-methyltransferase catalyzes a new methylation reaction responsible for sterol diversity [Research Articles]

Primitive sterol evolution plays an important role in fossil record interpretation and offers potential therapeutic avenues for human disease resulting from nematode infections. Recognizing that C4-methyl stenol products [8(14)-lophenol] can be synthesized in bacteria while C4-methyl stanol products (dinosterol) can be synthesized in dinoflagellates and preserved as sterane biomarkers in ancient sedimentary rock is key to eukaryotic sterol evolution. In this regard, nematodes have been proposed to convert dietary cholesterol to 8(14)-lophenol by a secondary metabolism pathway that could involve sterol C4 methylation analogous to the C2 methylation of hopanoids (radicle-type mechanism) or C24 methylation of sterols (carbocation-type mechanism). Here, we characterized dichotomous cholesterol metabolic pathways in Caenorhabditis elegans that generate 3-oxo sterol intermediates in separate paths to lophanol (4-methyl stanol) and 8(14)-lophenol (4-methyl stenol). We uncovered alternate C3-sterol oxidation and 7 desaturation steps that regulate sterol flux from which branching metabolite networks arise, while lophanol/8(14)-lophenol formation is shown to be dependent on a sterol C4α-methyltransferse (4-SMT) that requires 3-oxo sterol substrates and catalyzes a newly discovered 3-keto-enol tautomerism mechanism linked to S-adenosyl-l-methionine-dependent methylation. Alignment-specific substrate-binding domains similarly conserved in 4-SMT and 24-SMT enzymes, despite minimal amino acid sequence identity, suggests divergence from a common, primordial ancestor in the evolution of methyl sterols. The combination of these results provides evolutionary leads to sterol diversity and points to cryptic C4-methyl steroidogenic pathways of targeted convergence that mediate lineage-specific adaptations.­­




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Adverse drug reactions

Clinical trials for regulatory approval are designed to test efficacy, but new drugs might have adverse reactions - reactions those trials aren’t designed to spot. To talk about those adverse reactions - how to spot them, how to report them and what to do about them, we're joined by Robin Ferner, from the West Midlands Centre for Adverse Drug...




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Glucose-Induced Reactive Oxygen Species Cause Apoptosis of Podocytes and Podocyte Depletion at the Onset of Diabetic Nephropathy

Katalin Susztak
Jan 1, 2006; 55:225-233
Complications




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C-Reactive Protein Is an Independent Predictor of Risk for the Development of Diabetes in the West of Scotland Coronary Prevention Study

Dilys J. Freeman
May 1, 2002; 51:1596-1600
Complications




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High glucose level and free fatty acid stimulate reactive oxygen species production through protein kinase C--dependent activation of NAD(P)H oxidase in cultured vascular cells

T Inoguchi
Nov 1, 2000; 49:1939-1945
Articles




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A World of Insults, a World of Reactions

You don't have to be a sports fan to know that something extraordinary happened in the World Cup soccer final last week. Ten minutes from the climactic end -- with his country's hopes, the championship and his place in the history books at stake -- French captain Zinedine Zidane violently...




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Capillary circulation and capillary reactions in the frog.

England, 1923.




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Capillary circulation and capillary reactions in the frog.

England, 1923.




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'A pioneer, a trailblazer' - Reaction to McGraw's retirement

Notre Dame coach Muffet McGraw retired after 33 seasons Wednesday. What she did for me in those four years, I came in as a girl and left as a woman.'' - WNBA player Kayla McBride, who played for Notre Dame from 2010-14.




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Drift estimation for stochastic reaction-diffusion systems

Gregor Pasemann, Wilhelm Stannat.

Source: Electronic Journal of Statistics, Volume 14, Number 1, 547--579.

Abstract:
A parameter estimation problem for a class of semilinear stochastic evolution equations is considered. Conditions for consistency and asymptotic normality are given in terms of growth and continuity properties of the nonlinear part. Emphasis is put on the case of stochastic reaction-diffusion systems. Robustness results for statistical inference under model uncertainty are provided.




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Genomic Analysis of Reactive Astrogliosis

Jennifer L. Zamanian
May 2, 2012; 32:6391-6410
Neurobiology of Disease




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Response of Neurons in the Lateral Intraparietal Area during a Combined Visual Discrimination Reaction Time Task

Jamie D. Roitman
Nov 1, 2002; 22:9475-9489
Behavioral




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How Street Artists Around the World Are Reacting to Life With COVID-19

Graffiti artists and muralists are sending messages of hope and despair with coronavirus public art




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Readers react to reports Nicola Sturgeon 'missed six coronavirus Cobra meetings'

Readers have been quick to voice their opinion after it was reported that Nicola Sturgeon missed six emergency coronavirus Cobra meetings.




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Allergic Reactions to Foods in Preschool-Aged Children in a Prospective Observational Food Allergy Study

Infants and children with diagnosed food allergy are at risk for acute, potentially life-threatening symptoms. Limited data are available on the frequency, severity, and circumstances of reactions and caretaker medical response.

This study describes food allergy reaction frequency, circumstances, and response. Pitfalls that may inform improved anticipatory guidance included lack of vigilance, misreading ingredient labels, allergen cross-contact, nonaccidental allergen feeding, and underutilization of epinephrine for severe reactions. (Read the full article)




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Acute Bacterial Osteoarticular Infections: Eight-Year Analysis of C-Reactive Protein for Oral Step-Down Therapy

Pediatric osteoarticular infections can be treated with successful microbiologic and clinical outcomes with a transition from parenteral to oral therapy. The best way to determine the timing of this transition is neither well studied nor standardized.

A total of 193 (99.5%) of 194 pediatric patients with acute bacterial osteoarticular infections were successfully transitioned to oral therapy, determined by using a combination of clinical findings and C-reactive protein levels, representing the largest single-center data set analyzed. (Read the full article)




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Trends in Adverse Reactions to Trimethoprim-Sulfamethoxazole

Antimicrobials are a medication class frequently implicated in pediatric adverse drug reactions (ADRs). Trimethoprim-sulfamethoxazole (TMP-SMX) is long recognized as a contributor to the burden of these undesired and unpredictable events.

TMP-SMX ADRs increased from 2000 to 2009, with the majority of children taking the antibiotic for skin and soft tissue infections. The significant increase in TMP-SMX prescribing for these infections may result in a continued increase of associated ADRs. (Read the full article)




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Vaccination Site and Risk of Local Reactions in Children 1 Through 6 Years of Age

Previous evaluations of local reactions after the fifth diphtheria-tetanus-acellular pertussis (DTaP) vaccine in children 4 to 6 years of age have revealed that vaccination in the thigh is associated with a lower risk of local reactions compared with vaccination in the arm.

Among children 12 to 35 months of age, injection of DTaP vaccine in the thigh is associated with a lower risk of local reactions compared with vaccination in the arm. (Read the full article)




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Diagnostic and Prognostic Value of Procalcitonin and C-Reactive Protein in Malnourished Children

Biomarkers such as C-reactive protein (CRP) and procalcitonin are elevated in children with severe bacterial infections. Children with severe malnutrition are at increased risk of bacterial infections and early markers for the diagnosis of infection in these children are needed.

Despite elevated values in severely malnourished children with invasive bacterial infection or infectious diarrhea, CRP and procalcitonin have limited diagnostic value. CRP could predict death in these children with a good negative predictive value. (Read the full article)




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Kids React to First-Gen Apple iPod

"It's like a cinderblock," one seven-year-old said of Apple's original MP3 player.




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The world's media react to the UEFA EURO 2016 final

Portgual's A Bola gave every player ten out of ten, L'Équipe were "devasted" and Cristiano Ronaldo was naturally a focus: we round up the world media reaction to the final.




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Crisis Group Reaction To Announcement of New Government of National Accord in Libya

Following UN Special Representative for Libya Bernardino León’s announcement of a new Government of National Accord, Joost Hiltermann, Crisis Group’s Middle East and North Africa Program Director, had the following reaction.




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China reacts to Trump comparing virus to Pearl Harbor, 9/11 attacks

Source: www.youtube.com - Thursday, May 07, 2020




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Office of Highway Safety Reactivates Grassroots Initiative to Promote Pedestrian Safety Month in October

Cooperative statewide effort to reduce pedestrian deaths and encourage safe walking habits.




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Office of Highway Safety Kicks Off New Safe Family Holiday Campaign & Reactivates SoberLift

Media Advisory:  November 22, 2019 Initiative reinforces the importance of safe driving behaviors during one of the busiest times of the year WHAT: The Delaware Office of Highway Safety (OHS) is launching its new Safe Family Holiday Campaign, as well as reactivating the SoberLift initiative ahead of Thanksgiving weekend. Through a combination of tactics – traditional […]




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Under-19 World Cup final: Bangladesh’s reaction after victory was ‘dirty’, says Indian skipper Priyam Garg

While Bangladesh captain Akbar Ali apologised for the "unfortunate incident", his Indian counterpart Priyam Garg felt it is something that should not have happened.







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Mock REST Backend Server for Angular and React Applications.

As I promised to continue the Angular/Ionic project series, as a developer perspective mock server is the most important to progress the development. We should not depend on the production or development API for front-end development. This post is about creating a simple Node Express server with mock JSON object files. You can import the project to any of the front-end applications like Angular, React, Ionic and VueJS projects.





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EPA Announces Roll Backs To Clean Power Plan; Industry Reacts

Continuing on U.S. President Trump’s campaign promise to revive the coal industry, on Tuesday, August 21, the Environmental Protection Agency (EPA) announced plans to significantly alter the Clean Power Plan (CPP), shrinking some of the emission reduction targets that were set in place under the CPP by former President Obama.




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East-West Center Launches Asia Reacts ‘tracker’ of Asia’s Reactions to the U.S. Presidential Election and Foreign Policy

WASHINGTON, D.C.(May 11, 2016) - The Asia Matters for America initiative of the East-West Center today launched a new online resource, Asia Reacts, which tracks Asia’s reactions to important developments in U.S.–Asia relations during and after the 2016 U.S. presidential election. The effort will monitor responses of Asian governments, media, and experts.




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Coronavirus – HMRC Stamp Office reacts to COVID-19 measures - UK

The UK HMRC Stamp Office has released details of how it will temporarily change its procedures to allow for the submission and payment of stamp duty in respect of transfers of shares in UK companies. The standard requirements of HMRC in order to st...




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Coronavirus: Nigerian govt reacts to alleged rift with states

The Secretary to the Government of the Federation, Boss Mustapha, says the PTF is not operating at variance with the state committees response on coronavirus. Mustapha is the Chairman, Presidential Task Force (PTF) on COVID-19. The SGF spoke at the PTF daily media briefing on Friday in Abuja. He insisted that the national response is […]

Coronavirus: Nigerian govt reacts to alleged rift with states




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Sheikh Tambuwal is dead, Atiku, Peter Obi react

Sheikh Haruna Tambuwal, father of Sokoto State Governor, Aminu Tambuwal is dead. He died on Friday at the age of 96 after a brief illness at his residence in Tambuwal Council of Sokoto. The 96-year-old is survived by children, including the governor, as well as grandchildren and great grandchildren. Being a devout Muslim, he has […]

Sheikh Tambuwal is dead, Atiku, Peter Obi react




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Online Annual General Meetings and more flexibility for corporate reorganisations – how the German legislator reacts with new corporate law measures to the Corovid-19 crisis

1. Upcoming German Annual General Meetings season 2020 A lot of German corporates have traditionally lined up their annual general meetings (AGM) for May, June and July. In the wake of the co-rona virus crisis, the boards of a large number of compa...




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Caterpillar Invasion in London Puts People at Risk of Deadly Allergic Reactions

Title: Caterpillar Invasion in London Puts People at Risk of Deadly Allergic Reactions
Category: Health News
Created: 4/30/2018 12:00:00 AM
Last Editorial Review: 5/1/2018 12:00:00 AM




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Mycobacterium tuberculosis Reactivates HIV-1 via Exosome-Mediated Resetting of Cellular Redox Potential and Bioenergetics

ABSTRACT

The synergy between Mycobacterium tuberculosis and human immunodeficiency virus-1 (HIV-1) interferes with therapy and facilitates the pathogenesis of both human pathogens. Fundamental mechanisms by which M. tuberculosis exacerbates HIV-1 infection are not clear. Here, we show that exosomes secreted by macrophages infected with M. tuberculosis, including drug-resistant clinical strains, reactivated HIV-1 by inducing oxidative stress. Mechanistically, M. tuberculosis-specific exosomes realigned mitochondrial and nonmitochondrial oxygen consumption rates (OCR) and modulated the expression of host genes mediating oxidative stress response, inflammation, and HIV-1 transactivation. Proteomics analyses revealed the enrichment of several host factors (e.g., HIF-1α, galectins, and Hsp90) known to promote HIV-1 reactivation in M. tuberculosis-specific exosomes. Treatment with a known antioxidant—N-acetyl cysteine (NAC)—or with inhibitors of host factors—galectins and Hsp90—attenuated HIV-1 reactivation by M. tuberculosis-specific exosomes. Our findings uncover new paradigms for understanding the redox and bioenergetics bases of HIV-M. tuberculosis coinfection, which will enable the design of effective therapeutic strategies.

IMPORTANCE Globally, individuals coinfected with the AIDS virus (HIV-1) and with M. tuberculosis (causative agent of tuberculosis [TB]) pose major obstacles in the clinical management of both diseases. At the heart of this issue is the apparent synergy between the two human pathogens. On the one hand, mechanisms induced by HIV-1 for reactivation of TB in AIDS patients are well characterized. On the other hand, while clinical findings clearly identified TB as a risk factor for HIV-1 reactivation and associated mortality, basic mechanisms by which M. tuberculosis exacerbates HIV-1 replication and infection remain poorly characterized. The significance of our research is in identifying the role of fundamental mechanisms such as redox and energy metabolism in catalyzing HIV-M. tuberculosis synergy. The quantification of redox and respiratory parameters affected by M. tuberculosis in stimulating HIV-1 will greatly enhance our understanding of HIV-M. tuberculosis coinfection, leading to a wider impact on the biomedical research community and creating new translational opportunities.




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Ehrlichia chaffeensis Uses an Invasin To Suppress Reactive Oxygen Species Generation by Macrophages via CD147-Dependent Inhibition of Vav1 To Block Rac1 Activation

ABSTRACT

The obligatory intracellular pathogen Ehrlichia chaffeensis lacks most factors that could respond to oxidative stress (a host cell defense mechanism). We previously found that the C terminus of Ehrlichia surface invasin, entry-triggering protein of Ehrlichia (EtpE; EtpE-C) directly binds mammalian DNase X, a glycosylphosphatidylinositol-anchored cell surface receptor and that binding is required to induce bacterial entry and simultaneously to block the generation of reactive oxygen species (ROS) by host monocytes and macrophages. However, how the EtpE-C–DNase X complex mediates the ROS blockade was unknown. A mammalian transmembrane glycoprotein CD147 (basigin) binds to the EtpE-DNase X complex and is required for Ehrlichia entry and infection of host cells. Here, we found that bone marrow-derived macrophages (BMDM) from myeloid cell lineage-selective CD147-null mice had significantly reduced Ehrlichia-induced or EtpE-C-induced blockade of ROS generation in response to phorbol myristate acetate. In BMDM from CD147-null mice, nucleofection with CD147 partially restored the Ehrlichia-mediated inhibition of ROS generation. Indeed, CD147-null mice as well as their BMDM were resistant to Ehrlichia infection. Moreover, in human monocytes, anti-CD147 partially abrogated EtpE-C-induced blockade of ROS generation. Both Ehrlichia and EtpE-C could block activation of the small GTPase Rac1 (which in turn activates phagocyte NADPH oxidase) and suppress activation of Vav1, a hematopoietic-specific Rho/Rac guanine nucleotide exchange factor by phorbol myristate acetate. Vav1 suppression by Ehrlichia was CD147 dependent. E. chaffeensis is the first example of pathogens that block Rac1 activation to colonize macrophages. Furthermore, Ehrlichia uses EtpE to hijack the unique host DNase X-CD147-Vav1 signaling to block Rac1 activation.

IMPORTANCE Ehrlichia chaffeensis is an obligatory intracellular bacterium with the capability of causing an emerging infectious disease called human monocytic ehrlichiosis. E. chaffeensis preferentially infects monocytes and macrophages, professional phagocytes, equipped with an arsenal of antimicrobial mechanisms, including rapid reactive oxygen species (ROS) generation upon encountering bacteria. As Ehrlichia isolated from host cells are readily killed upon exposure to ROS, Ehrlichia must have evolved a unique mechanism to safely enter phagocytes. We discovered that binding of the Ehrlichia surface invasin to the host cell surface receptor not only triggers Ehrlichia entry but also blocks ROS generation by the host cells by mobilizing a novel intracellular signaling pathway. Knowledge of the mechanisms by which ROS production is inhibited may lead to the development of therapeutics for ehrlichiosis as well as other ROS-related pathologies.




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Immediate reactions with glatiramer acetate: Diagnosis of allergy and desensitization protocols

Purpose of review

Diverse adverse events have been associated with administration of glatiramer acetate (GA), mainly local reactions at the injection site. Other, less frequent generalized reactions include isolated postinjection reactions and anaphylaxis, which may lead to discontinuation of GA.

Recent findings

Close collaboration between the allergy and neurology departments is needed to study adverse reactions to GA. The allergy study should include a detailed history and skin prick and intradermal tests with GA and, if possible, determination of specific IgE levels. Furthermore, the implication of other drugs should be ruled out.

Summary

An accurate diagnosis of reactions to GA is essential if we are to confirm or rule out allergy to GA. When an allergy diagnosis is confirmed or firmly suspected based on clinical evidence, desensitization protocols are increasingly seen as safe methods for reintroduction of GA.




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Complexes between C-Reactive Protein and Very Low Density Lipoprotein Delay Bacterial Clearance in Sepsis [INFECTIOUS DISEASE AND HOST RESPONSE]

Key Points

  • Kupffer cells phagocytose both bacteria and CRP–VLDL complexes.

  • High levels of CRP–VLDL complexes delay bacterial clearance.

  • Pch disrupts CRP–VLDL complexes to improve bacterial clearance.




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    Serine Phosphorylation of the STAT1 Transactivation Domain Promotes Autoreactive B Cell and Systemic Autoimmunity Development [AUTOIMMUNITY]

    Key Points

  • STAT1-pS727 is required for SLE-associated AFC, GC, and autoantibody responses.

  • STAT1-pS727 in B cells promotes autoimmune AFC, GC, and autoantibody responses.

  • STAT1-pS727 is not required for foreign Ag– or gut microbiota–driven responses.




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    T Cell Responses Induced by Attenuated Flavivirus Vaccination Are Specific and Show Limited Cross-Reactivity with Other Flavivirus Species [Vaccines and Antiviral Agents]

    Members of the flavivirus genus share a high level of sequence similarity and often circulate in the same geographical regions. However, whether T cells induced by one viral species cross-react with other related flaviviruses has not been globally addressed. In this study, we tested pools of epitopes derived from dengue (DENV), Zika (ZIKV), Japanese encephalitis (JEV), West Nile (WNV), and yellow fever (YFV) viruses by intracellular cytokine staining (ICS) using peripheral blood mononuclear cells (PBMCs) of individuals naturally exposed to DENV or immunized with DENV (TV005) or YF17D vaccine. CD8 T cell responses recognized epitopes from multiple flaviviruses; however, the magnitude of cross-reactive responses was consistently severalfold lower than those to the autologous epitope pools and was associated with lower expression of activation markers such as CD40L, CD69, and CD137. Next, we characterized the antigen sensitivity of short-term T cell lines (TCL) representing 29 different individual epitope/donor combinations. TCL derived from DENV monovalent vaccinees induced CD8 and CD4 T cells that cross-reacted within the DENV serocomplex but were consistently associated with >100-fold-lower antigen sensitivity for most other flaviviruses, with no cross-recognition of YFV-derived peptides. CD8 and CD4 TCL from YF17D vaccinees were associated with very limited cross-reactivity with any other flaviviruses and in five out of eight cases >1,000-fold-lower antigen sensitivity. Overall, our data suggest limited cross-reactivity for both CD4 and CD8 T cell responses between flaviviruses and have implications for understanding immunity elicited by natural infection and strategies to develop live attenuated vaccines against flaviviral species.

    IMPORTANCE The envelope (E) protein is the dominant target of neutralizing antibodies for dengue virus (DENV) and yellow fever virus (YFV). Accordingly, several DENV vaccine constructs use the E protein in a live attenuated vaccine format, utilizing a backbone derived from a heterologous flavivirus (such as YF) as a delivery vector. This backbone comprises the nonstructural (NS) and capsid (C) antigens, which are dominant targets of T cell responses. Here, we demonstrate that cross-reactivity at the level of T cell responses among different flaviviruses is very limited, despite high levels of sequence homology. Thus, the use of heterologous flavivirus species as a live attenuated vaccine vector is not likely to generate optimal T cell responses and might thus impair vaccine performance.