Phosphorylation of CRYAB induces a condensatopathy to worsen post-myocardial infarction left ventricular remodeling

Protein aggregates are emerging therapeutic targets in rare monogenic causes of cardiomyopathy and amyloid heart disease, but their role in more prevalent heart-failure syndromes remains mechanistically unexamined. We observed mislocalization of desmin and sarcomeric proteins to aggregates in human myocardium with ischemic cardiomyopathy and in mouse hearts with post-myocardial infarction ventricular remodeling, mimicking findings of autosomal-dominant cardiomyopathy induced by the R120G mutation in the cognate chaperone protein CRYAB. In both syndromes, we demonstrate increased partitioning of CRYAB phosphorylated on serine 59 to NP40-insoluble aggregate-rich biochemical fraction. While CRYAB undergoes phase separation to form condensates, the phosphomimetic mutation of serine 59 to aspartate (S59D) in CRYAB mimics R120G-CRYAB mutants with reduced condensate fluidity, formation of protein aggregates, and increased cell death. Conversely, changing serine to alanine (phosphorylation-deficient mutation) at position 59 (S59A) restored condensate fluidity and reduced both R120G-CRYAB aggregates and cell death. In mice, S59D CRYAB knockin was sufficient to induce desmin mislocalization and myocardial protein aggregates, while S59A CRYAB knockin rescued left ventricular systolic dysfunction after myocardial infarction and preserved desmin localization with reduced myocardial protein aggregates. 25-Hydroxycholesterol attenuated CRYAB serine 59 phosphorylation and rescued post-myocardial infarction adverse remodeling. Thus, targeting CRYAB phosphorylation-induced condensatopathy is an attractive strategy to counter ischemic cardiomyopathy

RAG suppresses group 2 innate lymphoid cells

Antigen specificity is the central trait distinguishing adaptive from innate immune function. Assembly of antigen-specific T cell and B cell receptors occurs through V(D)J recombination mediated by the Recombinase Activating Gene endonucleases RAG1 and RAG2 (collectively called RAG). In the absence of RAG, mature T and B cells do not develop and thus RAG is critically associated with adaptive immune function. In addition to adaptive T helper 2 (Th2) cells, group 2 innate lymphoid cells (ILC2s) contribute to type 2 immune responses by producing cytokines like Interleukin-5 (IL-5) and IL-13. Although it has been reported that RAG expression modulates the function of innate natural killer (NK) cells, whether other innate immune cells such as ILC2s are affected by RAG remains unclear. We find that in RAG-deficient mice, ILC2 populations expand and produce increased IL-5 and IL-13 at steady state and contribute to increased inflammation in atopic dermatitis (AD)-like disease. Furthermore, we show that RAG modulates ILC2 function in a cell-intrinsic manner independent of the absence or presence of adaptive T and B lymphocytes. Lastly, employing multiomic single cell analyses of RAG1 lineage-traced cells, we identify key transcriptional and epigenomic ILC2 functional programs that are suppressed by a history of RAG expression. Collectively, our data reveal a novel role for RAG in modulating innate type 2 immunity through suppression of ILC2s

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Two-hit mouse model of heart failure with preserved ejection fraction combining diet-induced obesity and renin-mediated hypertension

Heart failure with preserved ejection fraction (HFpEF) is increasingly common but its pathogenesis is poorly understood. The ability to assess genetic and pharmacologic interventions is hampered by the lack of robust preclinical mouse models of HFpEF. We developed a novel two-hit model, which combines obesity and insulin resistance with chronic pressure overload to recapitulate clinical features of HFpEF. C57Bl6/NJ mice fed a high-fat diet (HFD) for \u3e 10 weeks were administered an AAV8-driven vector resulting in constitutive overexpression of mouse Renin1d. HFD-Renin (aka HFpEF ) mice demonstrated obesity and insulin resistance, moderate left ventricular hypertrophy, preserved systolic function, and diastolic dysfunction indicated by echocardiographic measurements; increased left atrial mass; elevated natriuretic peptides; and exercise intolerance. Transcriptomic and metabolomic profiling of HFD-Renin myocardium demonstrated upregulation of pro-fibrotic pathways and downregulation of metabolic pathways, in particular branched chain amino acid catabolism, similar to human HFpEF. Treatment with empagliflozin, an effective but incompletely understood HFpEF therapy, improved multiple endpoints. The HFD-Renin mouse model recapitulates key features of human HFpEF and will enable studies dissecting the contribution of individual pathogenic drivers to this complex syndrome. Additional preclinical HFpEF models allow for orthogonal studies to increase validity in assessment of interventions

Single-cell expression analysis of ductal carcinoma in situ identifies complex genotypic-phenotypic relationships altering epithelial composition

UNLABELLED: Ductal carcinoma in situ (DCIS) is a risk factor for subsequent invasive breast cancer (IBC). To identify events in DCIS that lead to invasive cancer, we performed single-cell RNA sequencing on DCIS lesions and matched normal breast tissue. Inferred copy-number variation was used to identify neoplastic epithelial cells from clinical specimens, which contained a mixture of DCIS and normal ducts. Phylogenetic analysis demonstrated intratumoral clonal heterogeneity that was associated with significant gene expression differences. Classification of epithelial cells into mammary cell states revealed that subclones contained a mixture of cell states, suggesting an ongoing pattern of differentiation after neoplastic transformation. Cell state proportions were significantly different based on estrogen receptor expression, with estrogen receptor-negative DCIS more closely resembling the distribution in the normal breast, particularly with respect to cells with basal characteristics. Specific alterations in cell state proportions were associated with progression to invasive cancer in a cohort of DCIS with longitudinal outcome. Ongoing transcription of key basement membrane (BM) genes occurred in specific subsets of epithelial cell states, including basal/myoepithelial, which are diminished in DCIS. In the transition to IBC, the BM protein laminin, but not COL4, was altered in DCIS adjacent to invasion. Loss of COL4, but not laminin, in an in vitro DCIS model led to an invasive phenotype. These findings suggest that the process of invasion is a loss-of-function event due to an imbalance in critical cell populations essential for BM integrity rather than a gain of an invasive phenotype by neoplastic cells. SIGNIFICANCE: Single-cell analyses reveal ductal carcinoma in situ comprises multiple genetic clones with significant phenotypic diversity and link alterations in epithelial cell states and basement membrane integrity with invasive breast cancer progression

Neutralizing antibody immune correlates in COVAIL trial recipients of an mRNA second COVID-19 vaccine boost

Neutralizing antibody titer has been a surrogate endpoint for guiding COVID-19 vaccine approval and use, although the pandemic\u27s evolution and the introduction of variant-adapted vaccine boosters raise questions as to this surrogate\u27s contemporary performance. For 985 recipients of an mRNA second bivalent or monovalent booster containing various Spike inserts [Prototype (Ancestral), Beta, Delta, and/or Omicron BA.1 or BA.4/5] in the COVAIL trial (NCT05289037), titers against 5 strains were assessed as correlates of risk of symptomatic COVID-19 ( COVID-19 ) and as correlates of relative (Pfizer-BioNTech Omicron vs. Prototype) booster protection against COVID-19 over 6 months of follow-up during the BA.2-BA.5 Omicron-dominant period. Consistently across the Moderna and Pfizer-BioNTech vaccine platforms and across all variant Spike inserts assessed, both peak and exposure-proximal ( predicted-at-exposure ) titers correlated with lower Omicron COVID-19 risk in individuals previously infected with SARS-CoV-2, albeit significantly less so in naïve individuals [e.g., exposure-proximal hazard ratio per 10-fold increase in BA.1 titer 0.74 (95% CI 0.59, 0.94) for naïve vs. 0.41 (95% CI 0.23, 0.64) for non-naïve; interaction p = 0.013]. Neutralizing antibody titer was a strong inverse correlate of Omicron COVID-19 in non-naïve individuals and a weaker correlate in naïve individuals, posing questions about how prior infection alters the neutralization correlate

Clinical impact of endoscopy in severely thrombocytopenic patients with hematologic malignancy experiencing gastrointestinal bleeding

BACKGROUND: Gastrointestinal bleeding (GIB) is a major cause of hospitalization worldwide. Patients with hematologic malignancies have a higher risk of GIB as a result of thrombocytopenia and platelet dysfunction. There is no consensus on the optimal platelet level that would be safe for endoscopic intervention, although a platelet level of \u3e 50 × 10 AIM: To assess the safety of endoscopic intervention of inpatients with hematological malignancies and severe thrombocytopenia presenting with acute overt GIB. METHODS: This is a single center retrospective study. The data was collected from the electronic health record from 2018 to 2020. Inpatients with hematologic malignancy who presented with acute overt GIB and platelet count ≤ 50 × 10 RESULTS: A total of 76 patients were identified. The mean platelet count is 24.3 in the endoscopy arm and 14.6 in the conservative management arm. There was no statistically significant difference between patients who had endoscopy CONCLUSION: Medical supportive treatment without endoscopy could be considered as an alternative to endoscopic therapy for patients with hematologic malignancy complicated by severe thrombocytopenia and acute non-variceal GIB

SLC35A2 gene product modulates paramyxovirus fusion events during infection

Paramyxoviruses are significant human and animal pathogens that include mumps virus (MuV), Newcastle disease virus (NDV) and the murine parainfluenza virus Sendai (SeV). Despite their importance, few host factors implicated in paramyxovirus infection are known. Using a recombinant SeV expressing destabilized eGFP (rSeVCdseGFP) in a loss-of-function CRISPR screen, we identified the CMP-sialic acid transporter (CST) gene SLC35A1 and the UDP-galactose transporter (UGT) gene SLC35A2 as essential for paramyxovirus infection. As expected, SLC35A1 knockout (KO) cells showed drastic reduction in infections with SeV, NDV and MuV due to the lack of cell surface sialic acids receptors. However, SLC35A2 KO cells revealed unknown critical roles for this factor in virus-cell and cell-to-cell fusion events for the different paramyxoviruses. While UGT was essential for virus-cell fusion during SeV entry to the cell, it was not required for NDV or MuV entry. Importantly, UGT promoted the formation of syncytia during MuV infection, suggesting a role in cell-to-cell virus spread. Our findings demonstrate that paramyxoviruses can bind to or enter A549 cells in the absence of canonical galactose-bound sialic-acid decorations and show that UGT facilitates paramyxovirus fusion processes involved in entry and spread