Demethylzeylasteral Targets the Sp1/AGAP2 Axis to Impair Autophagic Flux and Induce Apoptosis in Hepatic Stellate Cells

Abstract

ABSTRACT Background and Aim Chronic liver injury‐induced liver fibrosis, if left untreated, can progress to cirrhosis or hepatocellular carcinoma, posing a serious threat to human health. Our previous study demonstrated that the natural product demethylzeylasteral (T‐96) alleviates liver fibrosis by suppressing ArfGAP with GTPase domain, ankyrin repeat and PH domain 2 (AGAP2) expression. However, the molecular mechanism underlying T‐96‐mediated regulation of AGAP2 remains unclear. This study aimed to clarify this mechanism and explore T‐96's role in liver fibrogenesis. Methods A series of molecular biological experiments (e.g., promoter activity assay, co‐immunoprecipitation, Western blot, and immunofluorescence) were performed to identify the transcription factor regulating AGAP2. The interaction between T‐96 and the transcription factor, as well as the degradation pathway of the latter, were investigated. Additionally, in vitro experiments were conducted to evaluate the effects of T‐96 on autophagy, apoptosis, and activation of hepatic stellate cells (HSCs). Results We identified Sp1 as the transcription factor mediating AGAP2 promoter activity. Mechanistically, T‐96 directly bound to Sp1 and promoted its degradation via the ubiquitin‐proteasome pathway, thereby downregulating AGAP2 expression. Furthermore, T‐96 impairs autophagic flux and induces apoptosis in activated HSCs through specific targeting of Sp1. Conclusions This study delineates a novel regulatory axis centered on Sp1 (T‐96/Sp1/AGAP2) in liver fibrosis, wherein T‐96 binds to Sp1 to promote its ubiquitination and degradation, subsequently inhibiting AGAP2 expression and inducing autophagic flux impairment/apoptosis in activated HSCs to alleviate liver fibrosis. These findings provide a theoretical foundation for developing targeted therapeutics and clinical strategies for fibrotic liver disease.

The authors' abstract, as published at the source. Journal of Gastroenterology and Hepatology, 2026 · DOI ↗