P4HA2 induces hepatic ductular reaction and biliary fibrosis in chronic cholestatic liver diseases

Abstract

Backgrounds: Prolyl-4-hydroxylases (P4Hs) are key enzymes in collagen synthesis. The P4HA subunit (P4HA1, P4HA2, and P4HA3) contains a substrate binding and catalyzation domain. We postulated that P4HA2 would play a key role in the cholangiocyte pathology of cholestatic liver diseases. Methods: We studied humans with primary biliary cholangitis (PBC) and Primary sclerosing cholangitis (PSC), P4HA2-/- mice injured by DDC, and P4HA2-/-/MDR2-/- double knockout mice. A parallel study was performed in patients with PBC, PSC, and controls using immunohistochemistry and immunofluorescence. In the murine model, the level of ductular reaction and biliary fibrosis were monitored by histology, qPCR, immunohistochemistry, and Western blotting. Expression of Yes1 Associated Transcriptional Regulator (YAP) phosphorylation was measured in isolated mouse cholangiocytes. The mechanism of P4HA2 was explored in RBE and 293T cell lines by using qPCR, Western blot, immunofluorescence, and co-immunoprecipitation. Results: The hepatic expression level of P4HA2 was highly elevated in patients with PBC or PSC. Ductular reactive cholangiocytes predominantly expressed P4HA2. Cholestatic patients with more severe liver injury correlated with levels of P4HA2 in the liver. In P4HA2-/- mice, there was a significantly reduced level of ductular reaction and fibrosis compared with controls in the DDC-induced chronic cholestasis. Decreased liver fibrosis and ductular reaction were observed in P4HA2-/-/MDR2-/- mice compared with MDR2-/- mice. Cholangiocytes isolated from P4HA2-/-/MDR2-/- mice displayed a higher level of YAP phosphorylation, resulting in cholangiocytes proliferation inhibition. In vitro studies showed that P4HA2 promotes RBE cell proliferation by inducing SAV1 degradation, eventually resulting in the activation of YAP. Conclusions: P4HA2 promotes hepatic ductular reaction and biliary fibrosis by regulating the SAV1-mediated Hippo signaling pathway. P4HA2 is a potential therapeutic target for PBC and PSC.

GRK2 mediated degradation of SAV1 initiates hyperplasia of fibroblast-like synoviocytes in rheumatoid arthritis

“…Recent cancer-related studies have determined that certain proteins ( e.g. , BCL-2, P4HA2) interact with SAV1, leading to its ubiquitination and proteasomal degradation 32 , 33 . However, the regulatory molecules for SAV1 in RA FLSs remain unknown.…”

Quantitative proteomics reveals the protective effects of Yinchenzhufu decoction against cholestatic liver fibrosis in mice by inhibiting the PDGFRβ/PI3K/AKT pathway

“…The DDC-induced mouse model is a classic chronic cholestatic animal model ( Fickert et al, 2007 ; Li et al, 2021 ). The main features of this model are bile duct reaction, hepatic inflammation, and fibrosis ( Arino et al, 2023 ; Zhang et al, 2023 ). In our previous studies, the blood biochemical indicators and liver tissue pathomorphology of mice induced by diet containing 0.025% DDC at 2, 4, 6, and 8 weeks were investigated ( Li et al, 2021 ).…”

Recombinant adeno-associated virus 8-mediated inhibition of microRNA let-7a ameliorates sclerosing cholangitis in a clinically relevant mouse model

“…DDC-fed (0.1%) mice are a xenobiotic- induced mouse model of cholangiopathy. It can induce reactive cholangiocytes, biliary inflammation, pericholangitis, periductal fibrosis, and ultimately portal-portal bridging affecting large bile ducts, which more closely resembles human sclerosing cholangitis and biliary fibrosis[ 34 , 35 ]. In the present study, using this experimental model of mice, we found that we demonstrate that a single dose of rAAV8-mediated inhibition of let-7a can protect mice from hepatic (biliary) injuries, biliary inflammation, proliferation, and fibrosis in experimental sclerosing cholangitis for 2 wk and 6 wk, suggesting that inhibition let-7a delivered by rAAV8 provides a potential therapeutic strategy for sclerosing cholangitis (Figure 8 ).…”