Biology subjects

Bastacky, S.

Publications and source records attributed to Bastacky, S..

4 recordsLinked to original sources

bioRxiv2024

Inducible deletion of Ezh2 in CD4+ T cells inhibits kidney T cell infiltration and prevents interstitial nephritis in MRL/lpr lupus-prone mice

Systemic lupus erythematosus is a remitting relapsing autoimmune disease characterized by autoantibody production and multi-organ involvement. T cell epigenetic dysregulation plays an important role in the pathogenesis of lupus. We have previously demonstrated upregulation of the key epigenetic regulator EZH2 in CD4+ T cells isolated from lupus patients. To further investigate the role of EZH2 in the pathogenesis of lupus, we generated a tamoxifen-inducible CD4+ T cell Ezh2 conditional knockout mouse on the MRL/lpr lupus-prone background. We demonstrate that Ezh2 deletion abrogates lupus-like disease and prevents T cell differentiation. Single-cell analysis suggests impaired T cell function and activation of programed cell death pathways in EZH2-deficient mice. Ezh2 deletion in CD4+ T cells restricts TCR clonal repertoire and prevents kidney-infiltrating effector CD4+ T cell expansion and tubulointerstitial nephritis, which has been linked to end-stage renal disease in patients with lupus nephritis.

immunology↗

bioRxiv2023

Calponin 2 harnesses metabolic reprogramming to determine kidney fibrosis

In the fibrotic kidneys, the extent of a formed deleterious microenvironment is determined by cellular mechanical forces. This process requires metabolism for energy; however, how cellular mechanics and metabolism are connected remains unclear. Our proteomics revealed that actin filament binding and cell metabolism are the two most dysregulated events in the fibrotic kidneys. As a prominent actin stabilizer, Calponin 2 (CNN2) is predominantly expressed in fibroblasts and pericytes. CNN2 knockdown preserves kidney function and alleviates fibrosis. Global proteomics profiled that CNN2 knockdown enhanced the activities of the key rate-limiting enzymes and regulators of fatty acid oxidation (FAO) in diseased kidneys. Inhibiting carnitine palmitoyltransferase 1 in the FAO pathway results in lipid accumulation and extracellular matrix deposition in the fibrotic kidneys, which were restored after CNN2 knockdown. In patients, increased serum CNN2 levels are correlated with lipid content. Bioinformatics and chromatin immunoprecipitation showed that CNN2 interactor, estrogen receptor 2 (ESR2) binds peroxisome proliferator-activated receptor- (PPAR) to transcriptionally regulate FAO downstream target genes expression amid kidney fibrosis. In vitro, ESR2 knockdown repressed the mRNA levels of PPAR and the key genes in the FAO pathway. Conversely, activation of PPAR reduced CNN2-induced matrix inductions. Our results suggest that balancing cell mechanics and metabolism is crucial to develop therapeutic strategies to halt kidney fibrosis.

pathology↗

bioRxiv2022

Ezh2 knockout in B cells impairs plasmablast differentiation and ameliorates lupus-like disease in MRL/lpr mice

ObjectivesEnhancer of zeste homolog 2 (EZH2) regulates B cell development and differentiation. We have previously demonstrated increased EZH2 expression in peripheral blood mononuclear cells isolated from lupus patients. The goal of this study was to evaluate the role of B cell EZH2 expression in lupus pathogenesis. MethodsWe generated an MRL/lpr mouse with floxed Ezh2, which was crossed with CD19-Cre mice to examine the effect of B cell EZH2 deficiency in MRL/lpr lupus-prone mice. Differentiation of B cells was assessed by flow cytometry. Single cell RNA sequencing and single cell B cell receptor sequencing were used to investigate compositional and functional changes of B cell subsets. In vitro B cell culture with an XBP1 inhibitor was performed. EZH2 and XBP1 mRNA levels in CD19+ B cells isolated from SLE patients and healthy controls were analyzed. ResultsWe show that Ezh2 deletion in B cells significantly decreased autoantibody production and improved glomerulonephritis. B cell development was altered in the bone marrow and spleen of EZH2-deficient mice. Differentiation of plasmablasts was impaired. Single cell RNA sequencing showed that XBP1, a key transcription factor in B cell development, is downregulated in the absence of EZH2. Inhibiting XBP1 in vitro impairs plasmablast development similar to EZH2-deficient mice. Single cell B cell receptor RNA sequencing revealed defective immunoglobulin class switch recombination in EZH2-deficient mice. In human lupus B cells, we observed a strong correlation between EZH2 and XBP1 mRNA expression levels. ConclusionEZH2 overexpression in B cells contributes to disease pathogenesis in lupus.

immunology↗

bioRxiv2019

Murine lupus is Neutrophil Elastase-independent in the MRL.Faslprmodel

Loss of tolerance to nuclear antigens and multisystem tissue destruction is a hallmark of systemic lupus erythematosus (SLE). Although the source of autoantigen in lupus remains elusive, a compelling hypothetical source is dead cell debris that drives autoimmune activation. Prior reports suggest that neutrophil extracellular traps (NETs) and their associated death pathway, NETosis, are sources of autoantigen in SLE. However, others and we have shown that inhibition of NETs by targeting the NADPH oxidase complex and peptidylarginine deiminase 4 (PADI4) did not ameliorate disease in spontaneous murine models of SLE. Furthermore, myeloperoxidase and PADI4 deletion did not inhibit induced lupus. Since NET formation may occur independently of any one mediator, to address this controversy, we genetically deleted an additional important mediator of NETs and neutrophil effector function, neutrophil elastase (ELANE), in the MRL.Faslpr model of SLE. ELANE deficiency, and by extension ELANE-dependent NETs, had no effect on SLE nephritis, dermatitis, anti-self response, or immune composition in MRL.Faslpr mice. Taken together with prior data from our group and others, these data further challenge the paradigm that NETs and neutrophils are pathogenic in SLE.

immunology↗