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Thakare, R.

Publications and source records attributed to Thakare, R..

2 recordsLinked to original sources

Dynamic S-acylation of GSDMA regulates pyroptosis

GSDMA, the primary member of the gasdermin family found in the skin, is critical for pathogen-induced pyroptosis during infection. Recent studies revealed that another gasdermin, GSDMD, undergoes palmitoylation during pyroptosis. However, whether and how the other gasdermin members undergo lipid modification remains poorly understood. Here, we demonstrate that GSDMA is S-acylated at the conserved cysteine residues in its N-terminal domain. We show that S-acylation of GSDMA promotes pyroptosis by facilitating its membrane anchoring and protein oligomerization, a mechanism distinct from the palmitoylation of GSDMD at the N-terminal C191 residue. Additionally, we present evidence that recombinant proteins of GSDMA and GSDMD can undergo S- acylation in vitro via direct interaction with palmitoyl-CoA, suggesting they potentially possess auto-acylation capacity. Furthermore, we identify ABHD17A as one of the deacylating enzymes that regulate the dynamic fatty acylation cycle of GSDMA. Overall, our studies reveal new molecular mechanisms underlying GSDMA function through S- acylation and underscore its important role in regulating pyroptosis mediated by GSDMA. HighlightsO_LIGSDMA is S-acylated at N-terminal conserved cysteine residues. C_LIO_LIGSDMA S-acylation facilitates membrane anchoring and protein oligomerization. C_LIO_LIGSDMA and GSDMD recombinant proteins can undergo S-acylation in vitro C_LIO_LIThe ABHD17A enzyme is involved in GSDMA deacylation. C_LI

biochemistry↗

Circulating bile acid levels direct sex-differences in liver cancer development

Hepatocellular carcinoma (HCC), the most common liver cancer, exhibits a higher incidence in males. Here, we report that mice lacking the bile acid regulators, Farnesoid X Receptor (FXR) and Small Heterodimer Partner (SHP), recapitulate the sex difference in liver cancer risk. Since few therapeutic options are available, we focused on understanding the intrinsic protection afforded to female livers. Transcriptomic analysis in control and FXR and SHP double knockout livers identified female-specific changes in metabolism, including amino acids, lipids, and steroids. We examined if the obtained transcriptomic signatures correlate with the survival outcomes for HCC patients to assess the translational potential of this murine HCC model. Gene signatures that are unique to the knockout females correspond with low-grade tumors and better survival. Ovariectomy blunts the metabolic changes in female livers and promotes tumorigenesis that, intriguingly, coincides with increases in serum bile acid (BA) levels. Despite similar genetics, we found higher serum BA concentrations in males, whereas female knockout mice excreted more BAs. Decreasing enterohepatic BA recirculation using cholestyramine, an FDA-approved resin, dramatically reduced the liver cancer burden in male mice. Overall, we reveal that sex-specific BA metabolism leading to lower circulating BA concentration protects female livers from developing cancer. Thus, targeting BA excretion may be a promising therapeutic strategy against HCC. SignificanceWe show that female-specific gene profiles identified in Fxr-/-, Shp-/- double knockout (DKO) mice correlate with better outcomes for HCC patients and uncover sex differences in circulation and excretion of bile acid. Overall, we demonstrate that increasing (ovariectomy or chemical injury) or decreasing (pharmacologically with FDA-approved resin) serum bile acids, not hepatic bile acids, promoted or alleviated liver cancer burden.

cancer biology↗