Reprogramming gut microbiota and targeting CXCL1: The multifaceted mechanism of PLP1 in ameliorating alcohol-induced liver disease

Hepatic inflammation and gut barrier dysfunction are core pathologies of alcohol-associated liver disease (ALD), yet effective therapies remain limited. Pueraria lobata polysaccharide (PLP1), a key active constituent of P. lobata Radix, has demonstrated hepatoprotective potential; however, its underlying mechanisms remain poorly understood. In this study, we sought to elucidate the therapeutic mechanism of PLP1 against experimental ALD by integrating proteomics, metabolomics, and gut microbiota analyses. We demonstrated that PLP1 initially functions through a microbiota-dependent pathway, transferable by fecal microbiota transplantation (FMT), to restore gut barrier integrity and suppress the gut‒LPS‒TLR4 inflammatory axis. Furthermore, PLP1 exerted a direct, microbiota-independent effect, maintaining its therapeutic efficacy in antibiotic-depleted mice. Mechanistically, PLP1 directly and specifically targets CXCL1, promoting its ubiquitin-mediated proteasomal degradation as confirmed by biophysical assays. The functional necessity of this interaction was definitively established via comprehensive genetic manipulation of CXCL1 in vitro and in vivo. Specifically, CXCL1 overexpression reversed PLP1’s benefits, whereas CXCL1 knockdown mimicked its effects and occluded any additional benefit from PLP1. Overall, PLP1 ameliorates ALD by independently targeting both extrinsic and intrinsic inflammatory triggers. This study reveals the multifaceted pharmacology of a natural polysaccharide and validates a dual-pronged therapeutic strategy for ALD.