Hepatic stellate cell activation and extracellular matrix deposition machinery (HSC activation/ECM deposition)

Hepatic stellate cell (HSC) activation and extracellular matrix (ECM) deposition machinery represents the central pathological process in liver fibrogenesis. In the healthy liver, HSCs are quiescent cells that store vitamin A; however, in response to chronic injury, they transdifferentiate into activated myofibroblasts characterized by increased proliferation, contractility, and fibrogenesis (Friedman, 2008). This activation is mediated by a complex network of signaling pathways, including TGF-β, PDGF, and CTGF, which drive the expression of alpha-smooth muscle actin (α-SMA) and the synthesis of fibrillar collagens (Bataller & Brenner, 2005). The resulting ECM deposition leads to the replacement of normal parenchyma with scar tissue, eventually progressing to cirrhosis and liver failure. Therapeutic strategies targeting this machinery aim to either prevent HSC activation, induce their reversion to a quiescent state, or promote the degradation of the accumulated ECM (Schuppan et al., 2018). Despite numerous clinical trials involving TGF-β inhibitors, lysyl oxidase-like 2 (LOXL2) antibodies, and various metabolic modulators, no specific antifibrotic therapy has yet been approved for widespread clinical use (Tsochatzis et al., 2020). The complexity of the machinery, involving multiple redundant pathways and cell-cell interactions, presents a significant challenge for drug development. Safety concerns often arise from the systemic inhibition of pathways like TGF-β, which play essential roles in normal tissue homeostasis and immune regulation.

Other names

HSC activation pathwayLiver fibrogenesis machineryMyofibroblast transformationHepatic fibrotic cascade

Inhibition of pro-fibrotic signaling (e.g., TGF-beta, PDGF), modulation of HSC activation, and inhibition of ECM cross-linking enzymes.