The adipocyte-derived hormone leptin increases trafficking of KATP and Kv2.1 channels to the pancreatic β-cell surface, resulting in membrane hyperpolarization and suppression of insulin secretion. We have previously shown that this effect of leptin is mediated by the NMDA subtype of glutamate receptors (NMDARs). It does so by potentiating NMDAR activity, thus enhancing Ca2+ influx and the ensuing downstream signaling events that drive channel trafficking to the cell surface. However, the molecular mechanism by which leptin potentiates NMDARs in β-cells remains unknown. Here, we report that leptin augments NMDAR function via Src kinase–mediated phosphorylation of the GluN2A subunit. Leptin-induced membrane hyperpolarization diminished upon pharmacological inhibition of GluN2A but not GluN2B, indicating involvement of GluN2A-containing NMDARs. GluN2A harbors tyrosine residues that, when phosphorylated by Src family kinases, potentiate NMDAR activity. We found that leptin increases phosphorylation of Tyr-418 in Src, an indicator of kinase activation. Pharmacological inhibition of Src or overexpression of a kinase-dead Src mutant prevented the effect of leptin, whereas a Src kinase activator peptide mimicked it. Using mutant GluN2A overexpression, we show that Tyr-1292 and Tyr-1387 but not Tyr-1325 are responsible for the effect of leptin. Importantly, β-cells from db/db mice, a type 2 diabetes mouse model lacking functional leptin receptors, or from obese diabetic human donors failed to respond to leptin but hyperpolarized in response to NMDA. Our study reveals a signaling pathway wherein leptin modulates NMDARs via Src to regulate β-cell excitability and suggests NMDARs as a potential target to overcome leptin resistance.

Influenza A virus (IAV) mutates rapidly, resulting in antigenic drift and poor year-to-year vaccine effectiveness. One challenge in designing effective vaccines is that genetic mutations frequently cause amino acid variations in IAV envelope protein hemagglutinin (HA) that create new N-glycosylation sequons; resulting N-glycans cause antigenic shielding, allowing viral escape from adaptive immune responses. Vaccine candidate strain selection currently involves correlating antigenicity with HA protein sequence among circulating strains, but quantitative comparison of site-specific glycosylation information may likely improve the ability to design vaccines with broader effectiveness against evolving strains. However, there is poor understanding of the influence of glycosylation on immunodominance, antigenicity, and immunogenicity of HA, and there are no well-tested methods for comparing glycosylation similarity among virus samples. Here, we present a method for statistically rigorous quantification of similarity between two related virus strains that considers the presence and abundance of glycopeptide glycoforms. We demonstrate the strength of our approach by determining that there was a quantifiable difference in glycosylation at the protein level between WT IAV HA from A/Switzerland/9715293/2013 (SWZ13) and a mutant strain of SWZ13, even though no N-glycosylation sequons were changed. We determined site-specifically that WT and mutant HA have varying similarity at the glycosylation sites of the head domain, reflecting competing pressures to evade host immune response while retaining viral fitness. To our knowledge, our results are the first to quantify changes in glycosylation state that occur in related proteins of considerable glycan heterogeneity. Our results provide a method for understanding how changes in glycosylation state are correlated with variations in protein sequence, which is necessary for improving IAV vaccine strain selection. Understanding glycosylation will be especially important as we find new expression vectors for vaccine production, as glycosylation state depends greatly on the host species.

Extracellular vesicles (EVs) secreted by the epididymal epithelium transfer to spermatozoa key proteins that are essential in promoting motility and subsequent fertilization success. Using the domestic cat model, the objectives were to (1) characterize and compare protein content of EVs between segments of the epididymis, and (2) compare EV protein compositions between normo- and teratospermic individuals (producing >60% of abnormal spermatozoa). Epididymal EVs from adult cats were isolated and assessed via liquid chromatography tandem MS. Both male types shared 3008 proteins in total, with 98 and 20 EV proteins unique to normospermic and teratospermic males, respectively. Expression levels of several proteins changed between epididymal segments in both male types. Several proteins in both groups were related to sperm motility (e.g. hexokinase 1, adenylate kinase isoenzyme) and zona pellucida or oolemma binding (e.g. disintegrin and metalloproteinase domain proteins, zona binding proteins 1 and 2). Interestingly, seven cauda-derived EV proteins trended downward in teratospermic compared with normospermic males, which may relate to poor sperm quality. Collective results revealed, for the first time, EV proteins related to sequential sperm maturation with differences observed between normospermic and teratospermic individuals.

No abstract

Mass spectrometry-based glycoproteomics has gone through some incredible developments over the last few years. Technological advances in glycopeptide enrichment, fragmentation methods, and data analysis workflows have enabled the transition of glycoproteomics from a niche application, mainly focused on the characterization of isolated glycoproteins, to a mature technology capable of profiling thousands of intact glycopeptides at once. In addition to numerous biological discoveries catalyzed by the technology, we are also observing an increase in studies focusing on global protein glycosylation and the relationship between multiple glycosylation sites on the same protein. It has become apparent that just describing protein glycosylation in terms of micro- and macro-heterogeneity, respectively the variation and occupancy of glycans at a given site, is not sufficient to describe the observed interactions between sites. In this perspective we propose a new term, meta-heterogeneity, to describe a higher level of glycan regulation: the variation in glycosylation across multiple sites of a given protein. We provide literature examples of extensive meta-heterogeneity on relevant proteins such as antibodies, erythropoietin, myeloperoxidase and a number of serum and plasma proteins. Furthermore, we postulate on the possible biological reasons and causes behind the intriguing meta-heterogeneity observed in glycoproteins.

The histopathological subtype of lung adenocarcinoma (LUAD) is closely associated with prognosis. Micropapillary or solid predominant LUAD tends to relapse after surgery at an early stage, whereas lepidic pattern shows a favorable outcome. However, the molecular mechanism underlying this phenomenon remains unknown. Here, we recruited 31 lepidic predominant LUADs (LR: low-risk subtype group) and 28 micropapillary or solid predominant LUADs (HR: high-risk subtype group). Tissues of these cases were obtained and label-free quantitative proteomic and bioinformatic analyses were performed. Additionally, prognostic impact of targeted proteins was validated using The Cancer Genome Atlas databases (n=492) and tissue microarrays composed of early-stage LUADs (n=228). A total of 192 differentially expressed proteins were identified between tumor tissues of LR and HR and three clusters were identified via hierarchical clustering excluding eight proteins. Cluster 1 (65 proteins) showed a sequential decrease in expression from normal tissues to tumor tissues of LR and then to HR and was predominantly enriched in pathways such as tyrosine metabolism and ECM-receptor interaction, and increased matched mRNA expression of 18 proteins from this cluster predicted favorable prognosis. Cluster 2 (70 proteins) demonstrated a sequential increase in expression from normal tissues to tumor tissues of LR and then to HR and was mainly enriched in pathways such as extracellular organization, DNA replication and cell cycle, and high matched mRNA expression of 25 proteins indicated poor prognosis. Cluster 3 (49 proteins) showed high expression only in LR, with high matched mRNA expression of 20 proteins in this cluster indicating favorable prognosis. Furthermore, high expression of ERO1A and FEN1 at protein level predicted poor prognosis in early-stage LUAD, supporting the mRNA results. In conclusion, we discovered key differentially expressed proteins and pathways between low-risk and high-risk subtypes of early-stage LUAD. Some of these proteins could serve as potential biomarkers in prognostic evaluation.

The Phillies have been the favorites in the Bryce Harper sweepstakes for months, and that speculation heated up over the weekend.

The tumor marker cancer antigen 15-3 (CA 15-3) is that most commonly used to monitor metastatic breast cancer during active therapy and surveillance for disease recurrence after treatment. The association of CA 15-3 and ¹⁸F-FDG PET/CT findings can be considered complementary, since any significant rise may indicate the presence of disease and imaging is able to map the tumor sites. Although current guidelines do not recommend the routine performance of CA 15-3 in asymptomatic patients being followed up after definitive breast cancer treatment, most oncologists perform serial assessment of the tumor markers as part of routine follow-up of patients. The aim of this study was to evaluate the correlation between CA 15-3 levels and ¹⁸F-FDG PET/CT scan findings in patients with recurrent breast cancer. Methods: This was a cross-sectional study with data collected retrospectively. Patients being evaluated for breast cancer recurrence with ¹⁸F-FDG PET/CT imaging and CA 15-3 level were included. Evaluation of the association between CA 15-3 levels and ¹⁸F-FDG PET/CT scan findings was then done. Results: In total, 154 cases were included in this study; 62 patients had recurrence (positive) on the ¹⁸F-FDG PET/CT scans, whereas 92 patients had normal (negative) findings on follow-up ¹⁸F-FDG PET/CT scans. There was an association between CA 15-3 levels and the presence or absence of recurrence on ¹⁸F-FDG PET/CT scans, with 84.4% (27/32) of patients who had elevated CA 15-3 levels having disease recurrence on ¹⁸F-FDG PET/CT and 84.4% (27/32) of patients who had elevated CA 15-3 levels having disease recurrence on ¹⁸F-FDG PET/CT as well as a correlation with the burden of metastases. Most patients with disease recurrence on ¹⁸F-FDG PET/CT, however, had normal CA 15-3 levels. Conclusion: Higher CA 15-3 levels correlate with breast cancer recurrence on ¹⁸F-FDG PET/CT as well as with burden of metastasis. Notably, CA 15-3 levels within the reference range do not exclude breast cancer disease recurrence since more than half of patients with recurrence had normal CA 15-3 levels. ¹⁸F-FDG PET/CT should therefore be considered in patients with suspected breast cancer recurrence but normal CA 15-3 levels.

A 77-year-old slice of cake from Queen Elizabeth II's wedding to Prince Philip was auctioned for $2,800.

A low-carbohydrate diet may help adults with type 2 diabetes gain better blood sugar control and make it possible to decrease diabetes medication, a new study suggests.

Study of workplace stress finds there's a better way to cope than relaxation.

Pennsylvania's rejection of a formal complaint from the state Catholic Conference over COVID aid and private school students highlights a messy dispute taking place in many states.

Here are strategies for creating strong, respectful, productive relationships between superintendents and school boards.

U.S. Ed Secretary DeVos has approved plans for 46 states, plus the District of Columbia and Puerto Rico. Still waiting: California, Florida, Oklahoma, and Utah.

What goes on behind all the closed doors in politics? Most teachers never get a chance to find out, writes teacher-turned-politician John Waldron.

The latest approvals mean 12 of the 17 state plans submitted so far for Every Student Succeeds Act implementation have been given the federal go-ahead.

U.S. Ed Secretary DeVos has approved plans for 46 states, plus the District of Columbia and Puerto Rico. Still waiting: California, Florida, Oklahoma, and Utah.

The ability to discern fact from fiction and to recognize reliable news is fundamental, writes News Literacy Project’s Charles Salter.

A statewide survey of educators in Tennessee provides critical insights into connections that exist between standards, curriculum, professional development, and ultimately student success.

U.S. Secretary of Education Betsy DeVos green-lighted California and Utah's plans to implement the Every Student Succeed Act. That means just one state is still waiting: Florida.

U.S. Secretary of Education Betsy DeVos has greenlighted two more Every Student Succeeds Act plans from Virginia and South Carolina. That brings the grand total of states with approved plans to 39, plus the District of Columbia and Puerto Rico.

U.S. Secretary of Education Betsy DeVos will hold a workforce event at a South Carolina drug manufacturer that employs hundreds of cash-strapped teachers in second jobs.

Education Secretary Betsy DeVos has finally OK'd Florida's plan to implement the Every Student Succeeds Act. That means that single state, plus Puerto Rico and the District of Columbia, has gotten the go-ahead for its plan.

It's pretty obvious by now that many Democrats are growing increasingly uncomfortable supporting charter schools. But New Hampshire lawmakers have taken the unusual step of rejecting federal charter school grant money.

Educators who work in personalized learning schools are adjusting instruction for remote, hybrid, and in-person learning.

That brings the number of states with approved plans to 44, plus the District of Columbia and Puerto Rico. Still awaiting the OK: California, Florida, Nebraska, North Carolina, Oklahoma, and Utah

Minnesota and West Virginia are the first two states that submitted plans in the fall to win federal approval.

That brings the number of states with approved plans to 44, plus the District of Columbia and Puerto Rico. Still awaiting the OK: California, Florida, Nebraska, North Carolina, Oklahoma, and Utah

Janiah Barker had 18 points and 11 rebounds, Lauren Betts had 17 points and 12 rebounds and the No. 5 UCLA women rolled past Pepperdine 91-54 on Tuesday. The Bruins (3-0) started the game with an 18-0 run. Ornela Muca, who led Pepperdine (1-2) with 20 points, made a 3-pointer to stop the run.

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