S100 Calcium-Binding Protein 16 (S100A16) Promotes Hepatic Stellate Cell Activation Via Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2)-mediated Glycolysis to Facilitate Liver Fibrosis.

Hepatic stellate cell (HSC) activation is a key mediator in hepatic fibrosis, with glycolysis serving a key regulatory function. S100 calcium-binding protein 16 (S100A16) has been associated with various pathologies; however, its function and underlying mechanisms in liver fibrosis remains elusive. This study aimed to elucidate the functional role of S100A16 in HSC activation and its interaction with Erb-B2 receptor tyrosine kinase 2 (ERBB2)-mediated glycolysis. Transforming growth factor-β1 (TGF-β1)-stimulated human liver stellate cells (LX2) and carbon tetrachloride (CCl4)-induced mice were used as in vitro and in vivo models, respectively. Cell proliferation and alpha-smooth muscle actin (α-SMA) expression were detected by Cell Counting Kit-8 (CCK-8) assay and immunofluorescence. Glycolysis was detected via measuring the extracellular acidification rate (ECAR), lactate production, glucose uptake, and glycolytic enzyme levels. Molecular interactions were analyzed through bioinformatics and co-immunoprecipitation. Liver injury and fibrosis were assessed using hematoxylin and eosin (H&E)/Masson staining. Expression of S100A16, ERBB2, and fibrosis markers were quantified using quantitative real-time PCR (qRT-PCR) and Western blot. S100A16 was upregulated in fibrotic liver tissues and TGF-β1-stimulated LX2 cells. TGF-β1 increased lactate production and glycolysis, whereas S100A16 knockdown produced the opposite effects. Additionally, TGF-β1 enhanced cell proliferation and upregulated α-SMA, Collagen 1, and Fibronectin levels, but these effects were attenuated by either S100A16 knockdown or glycolysis inhibition. S100A16 interacted with ERBB2 and promoted its expression. ERBB2 knockdown reduced TGF-β1-induced glycolysis and HSC activation, along with reduced cell proliferation, effects that were inhibited by S100A16 overexpression. Furthermore, S100A16 knockdown ameliorated CCl4-induced liver injury and fibrosis, decreased serum lactate levels, and reduced S100A16 and ERBB2 expression, thereby suppressing glycolysis. Collectively, S100A16 promotes HSC activation and liver fibrosis through ERBB2-mediated glycolysis, highlighting the S100A16-ERBB2-glycolysis axis as a potential therapeutic target.