The protease activated receptor 2 - CCAAT/enhancer-binding protein beta - SerpinB3 axis inhibition as a novel strategy for the treatment of non-alcoholic steatohepatitis.

OBJECTIVE: The serine protease inhibitor SerpinB3 has been described as critical mediator of liver fibrosis and it has been recently proposed as an additional hepatokine involved in NASH development and insulin resistance. Protease Activated Receptor 2 has been identified as a novel regulator of hepatic metabolism. A targeted therapeutic strategy for NASH has been investigated, using 1-Piperidine Propionic Acid (1-PPA), since this compound has been recently proposed as both Protease Activated Receptor 2 and SerpinB3 inhibitor. METHODS: The effect of SerpinB3 on inflammation and fibrosis genes was assessed in human macrophage and stellate cell lines. Transgenic mice, either overexpressing SerpinB3 or carrying Serpinb3 deletion and their relative wild type strains, were used in experimental NASH models. Subgroups of SerpinB3 transgenic mice and their controls were also injected with 1-PPA to assess the efficacy of this compound in NASH inhibition. RESULTS: 1-PPA did not present significant cell and organ toxicity and was able to inhibit SerpinB3 and PAR2 in a dose-dependent manner. This effect was associated to a parallel reduction of the synthesis of the molecules induced by endogenous SerpinB3 or by its paracrine effects both in vitro and in vivo, leading to inhibition of lipid accumulation, inflammation and fibrosis in experimental NASH. At mechanistic level, the antiprotease activity of SerpinB3 was found essential for PAR2 activation, determining upregulation of the CCAAT Enhancer Binding Protein beta (C/EBP-ß), another pivotal regulator of metabolism, inflammation and fibrosis, which in turn determined SerpinB3 synthesis. CONCLUSIONS: 1-PPA treatment was able to inhibit the PAR2 - C/EBP-ß - SerpinB3 axis and to protect from NASH development and progression, supporting the potential use of a similar approach for a targeted therapy of NASH.

Histidine-rich glycoprotein in metabolic dysfunction-associated steatohepatitis-related disease progression and liver carcinogenesis.

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD), previously non-alcoholic fatty liver disease (NAFLD), is a leading cause of chronic liver disease worldwide. In 20%-30% of MASLD patients, the disease progresses to metabolic dysfunction-associated steatohepatitis (MASH, previously NASH) which can lead to fibrosis/cirrhosis, liver failure as well as hepatocellular carcinoma (HCC). Here we investigated the role of histidine-rich glycoprotein (HRG), a plasma protein produced by hepatocytes, in MASLD/MASH progression and HCC development. Methods: The role of HRG was investigated by morphological, cellular, and molecular biology approaches in (a) HRG knock-out mice (HRG-/- mice) fed on a CDAA dietary protocol or a MASH related diethyl-nitrosamine/CDAA protocol of hepatocarcinogenesis, (b) THP1 monocytic cells treated with purified HRG, and (c) well-characterized cohorts of MASLD patients with or without HCC. Results: In non-neoplastic settings, murine and clinical data indicate that HRG increases significantly in parallel with disease progression. In particular, in MASLD/MASH patients, higher levels of HRG plasma levels were detected in subjects with extensive fibrosis/cirrhosis. When submitted to the pro-carcinogenic protocol, HRG-/- mice showed a significant decrease in the volume and number of HCC nodules in relation to decreased infiltration of macrophages producing pro-inflammatory mediators, including IL-1ß, IL-6, IL-12, IL-10, and VEGF as well as impaired angiogenesis. The histopathological analysis (H-score) of MASH-related HCC indicate that the higher HRG positivity in peritumoral tissue significantly correlates with a lower overall patient survival and an increased recurrence. Moreover, a significant increase in HRG plasma levels was detected in cirrhotic (F4) patients and in patients carrying HCC vs. F0/F1 patients. Conclusion: Murine and clinical data indicate that HRG plays a significant role in MASLD/MASH progression to HCC by supporting a specific population of tumor-associated macrophages with pro-inflammatory response and pro-angiogenetic capabilities which critically support cancer cell survival. Furthermore, our data suggest HRG as a possible prognostic predictor in HCC patients with MASLD/MASH-related HCCs.

Efecto del ácido alfa lipoico y la pirfenidona en la modulación antioxidante celular contra el daño oxidativo / Effects of alpha lipoic acid and pirfenidone on liver cells antioxidant modulation against oxidative damage

Background: Liver fibrogenic processes are related to cellular redox state. Glutathione (GSH) is the major cellular antioxidant. GSH induced activation could be related to antifibrogenic effects. Aim: To explore the association between the antifibrogenic effect and pro-antioxidant mechanisms of alpha-lipoic acid (ALA) and pirfenidone (PFD). Material and Methods: HepG2 cells and primary HSC cultures were exposed to menadione 0.1 μM (MEN) as oxidative stress inducer and treated to ALA (5 mM) or PFD (10 μM, 100 μM y 1000 μM). Results: In HSC, PFD decreased cell proliferation and the expression of COL1A1, TGF-β1, TIMP1, IL6, TNFα and MCP1 induced by MEN. Furthermore it was confirmed that ALA and PFD activate diverse antioxidants mediators, however MEN decreases this response. Then, MEN, ALA and PFD induce an antioxidant response, the first one as a response to injury and the latter two as pro-antioxidant inducers. Therefore, when cells are exposed to oxidative stress, endogenous systems activate a battery of mediators that increase the antioxidant potential. When these cells are treated with ALA and PFD, de novo formation of protective genes decreases since previous elicited protection induced in response to injury, enhance ALA and PFD effects. Conclusion: Regardless of the route of action, ALA and PFD induce the biosynthesis of antioxidants mediators which is associated with modulation of fibrogenic processes.