Upregulation of GLT25D1 in Hepatic Stellate Cells Promotes Liver Fibrosis via the TGF-β1/SMAD3 Pathway In Vivo and In vitro

Abstract

Background and Aims: Collagen β(1-O) galactosyltransferase 25 domain 1 (GLT25D1) is associated with collagen production and glycosylation, and its knockout in mice results in embryonic death. However, its role in liver fibrosis remains elusive, particularly in hepatic stellate cells (HSCs), the primary collagen-producing cells associated with liver fibrogenesis. Herein, we aimed to elucidate the role of GLT25D1 in HSCs. Methods: Bile duct ligation (BDL)induced mouse liver fibrosis models, primary mouse HSCs (mHSCs), and transforming growth factor beta 1 (TGF-β1)stimulated LX-2 human hepatic stellate cells were used in in vivo and in vitro studies. Stable LX-2 cell lines with either GLT25D1 overexpression or knockdown were established using lentiviral transfection. RNA-seq was performed to investigate the genomic differences. HPLC-MS/MS were used to identify glycosylation sites. Scanning electronic microscopy (SEM) and second-harmonic generation/two-photon excited fluorescence (SHG/TPEF) were used to image collagen fibril morphology. Results: GLT25D1 expression was upregulated in nonparenchymal cells in human cirrhotic liver tissues. Meanwhile, its knockdown attenuated collagen deposition in BDL-induced mouse liver fibrosis and inhibited mHSC activation. GLT25D1 was overexpressed in activated versus quiescence LX-2 cells and regulated in vitro LX-2 cell activation, including proliferation, contraction, and migration. GLT25D1 also significantly increased liver fibrogenic gene and protein expression. GLT25D1 upregulation promoted HSC activa-tion and enhanced collagen expression through the TGF-β1/ SMAD signaling pathway. Mass spectrometry showed that GLT25D1 regulated the glycosylation of collagen in HSCs, affecting the diameter of collagen fibers. Conclusions: Collectively, the upregulation of GLT25D1 in HSCs promoted the progression of liver fibrosis by affecting HSCs activation and collagen stability.

Hepatic Stellate Cell- and Liver Microbiome-Specific Delivery System for Dihydrotanshinone I to Ameliorate Liver Fibrosis

“…The BDL rat model of hepatic fibrosis is commonly used to evaluate therapeutic approaches for liver fibrosis. , In this model, the ligation of the bile duct leads to the accumulation of bile acids, causing inflammatory reactions and chronic damage to hepatic tissue. H&E staining results revealed presence of newly formed bile duct-like structures and extensive parenchymal necrosis in the livers of rats in BDL group.…”

The Versatility of Collagen in Pharmacology: Targeting Collagen, Targeting with Collagen

“…This activity plays a crucial role in the stability and function of collagen fibrils in connective tissues. In this sense, the abolition or downregulation of GLT25D1 expression leads to an accumulation of type I collagen in the ER [ 107 ], and impairs collagen deposition in a bile duct ligation-induced liver fibrosis mouse model [ 108 ]. However, no drug targeting Glt25d1 or Glt25d2 has been reported to date.…”

Ongoing involvers and promising therapeutic targets of hepatic fibrosis: The hepatic immune microenvironment

“…On the one hand, TNF-α and IL-1β can inhibit HSCs apoptosis by up-regulating the expression of TIMP-1 and down-regulating the expression of BMP and activin membrane-bound inhibitor of HSCs ( 82 – 85 ). Macrophages are also able to up-regulate PI3K-AKT-mTOR and p38 mitogen-activated protein kinase (p38 MAPK) pathway in HSCs to promote the HSCs movement, and also activate TGF-β/smad pathway to promote their proliferation and contraction, and promote the production of type I and type III collagen ( 86 ). Moreover, the activated HSCs further affect the function of macrophages, and they interactively promote the progression of hepatic fibrosis.…”