Congratulations to Mengwei Zang, MD, PhD and the Zang Lab on their publication in Aging Cell!

Dr. Zang is a Professor with the Sam and Ann Barshop Institute for Longevity and Aging Studies and the Department of Molecular Medicine.  She is the Ewing Halsell Distinguished Chair in Research and the Associate Director of the MD/PhD Program at UT Health San Antonio.

Age-dependent loss of hepatic SIRT1 enhances NLRP3 inflammasome signaling and impairs capacity for liver fibrosis resolution
Jennifer Adjei-Mosi, Qing Sun, Steven Blake Smithson, Gavyn Lee Shealy, Krupa Dhruvitha Amerineni, Zerong Liang, Hanqing Chen, Mei Wang, Qinggong Ping, Jingyan Han, Masahiro Morita, Amrita Kamat, Nicolas Musi, and Mengwei Zang.
Aging Cell. 2023 Mar 31;e13811. doi: 10.1111/acel.13811. Online ahead of print.


Our studies indicate that the longevity factor SIRT1 is implicated in metabolic disease; however, whether and how hepatocyte-specific SIRT1 signaling is involved in liver fibrosis remains undefined. We characterized a functional link of age-mediated defects in SIRT1 to the NLRP3 inflammasome during age-related liver fibrosis. In multiple experimental murine models of liver fibrosis, we compared the development of liver fibrosis in young and old mice, as well as in liver-specific SIRT1 knockout (SIRT1 LKO) mice and wild-type (WT) mice. Liver injury, fibrosis, and inflammation were assessed histologically and quantified by real-time PCR analysis. In a model of hepatotoxin-induced liver fibrosis, old mice displayed more severe and persistent liver fibrosis than young mice during liver injury and after injury cessation, as characterized by inhibition of SIRT1, induction of NLRP3, infiltration of macrophages and neutrophils, activation of hepatic stellate cells (HSCs), and excessive deposition and remodeling of the extracellular matrix. Mechanistically, deletion of SIRT1 in hepatocytes resulted in NLRP3 and IL-1β induction, pro-inflammatory response, and severe liver fibrosis in young mice, mimicking the ability of aging to impair the resolution of established fibrosis. In an aging mouse model, chronic-plus-binge alcohol feeding-induced liver fibrosis was attenuated by treatment with MCC950, a selective NLRP3 inhibitor. NLRP3 inhibition ameliorated alcoholic liver fibrosis in old mice by repressing inflammation and reducing hepatocyte-derived danger signaling-ASK1 and HMGB1. In conclusion, age-dependent SIRT1 defects lead to NLRP3 activation and inflammation, which in turn impairs the capacity to resolve fibrosis during aging.

Keywords: MCC950; NLRP3 inflammasome; aging; alcohol-associated liver disease; hepatic stellate cells (HSCs); hepatocyte-specific SIRT1 knockout; liver fibrosis.

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