Histidine kinase NME1 and NME2 are involved in TGF-β1-induced HSC activation and CCl4-induced liver fibrosis

The histidine phosphatase LHPP of Penaeus vannamei is involved in shrimp hemocytes apoptosis

LHPP (Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase) is a protein histidine phosphatase that modulates a hidden posttranslational modification called histidine phosphorylation. LHPP also acts as a tumor suppressor, which plays a pivotal role in various cellular processes. However, whether LHPP participates in the regulation of invertebrate's immunity is still unknown. Here we characterized a LHPP homolog in P. vannamei (designated PvLHPP), with a 807 bp length of open reading frame (ORF) encoding a putative protein of 268 amino acids. Sequence analysis revealed that PvLHPP contains a typical hydrolase 6 and hydrolase-like domain, which was conserved from invertebrate to vertebrate. PvLHPP was ubiquitously expressed in tissues and induced in hemocyte and hepatopancreas by Vibrio parahaemolyticus, Streptococcus iniae and white spot syndrome virus (WSSV) challenge, indicating that PvLHPP participated in the immune responses. Moreover, silencing of PvLHPP followed by V. parahaemolyticus inhibited hemocyte apoptosis. This study enriches our current insight on shrimp immunity, and provides novel perspective to understand immune-regulatory role of PvLHPP.

SARA suppresses myofibroblast precursor transdifferentiation in fibrogenesis in a mouse model of scleroderma

We previously reported that Smad anchor for receptor activation (SARA) plays a critical role in maintaining epithelial cell phenotype. Here, we show that SARA suppressed myofibroblast precursor transdifferentiation in a mouse model of scleroderma. Mice overexpressing SARA specifically in PDGFR-β+ pericytes and pan-leukocytes (SARATg) developed significantly less skin fibrosis in response to bleomycin injection compared with wild-type littermates (SARAWT). Single-cell RNA-Seq analysis of skin PDGFR-β+ cells implicated pericyte subsets assuming myofibroblast characteristics under fibrotic stimuli, and SARA overexpression blocked the transition. In addition, a cluster that expresses molecules associated with Th2 cells and macrophage activation was enriched in SARAWT mice, but not in SARATg mice, after bleomycin treatment. Th2-specific Il-31 expression was increased in skin of the bleomycin-treated SARAWT mice and patients with scleroderma (or systemic sclerosis, SSc). Receptor-ligand analyses indicated that lymphocytes mediated pericyte transdifferentiation in SARAWT mice, while with SARA overexpression the myofibroblast activity of pericytes was suppressed. Together, these data suggest a potentially novel crosstalk between myofibroblast precursors and immune cells in the pathogenesis of SSc, in which SARA plays a critical role.

Recombinant truncated latency-associated peptide alleviates liver fibrosis in vitro and in vivo via inhibition of TGF-β/Smad pathway

Background

Liver fibrosis is a progressive liver injury response. Transforming growth factor β1 (TGF-β1) is oversecreted during liver fibrosis and promotes the development of liver fibrosis. Therapeutic approaches targeting TGF-β1 and its downstream pathways are essential to inhibit liver fibrosis. The N-terminal latency-associated peptide (LAP) blocks the binding of TGF-β1 to its receptor. Removal of LAP is critical for the activation of TGF-β1. Therefore, inhibition of TGF-β1 and its downstream pathways by LAP may be a potential approach to affect liver fibrosis.

Methods

Truncated LAP (tLAP) plasmids were constructed. Recombinant proteins were purified by Ni affinity chromatography. The effects of LAP and tLAP on liver fibrosis were investigated in TGF-β1-induced HSC-T6 cells, AML12 cells and CCl₄-induced liver fibrosis mice by real time cellular analysis (RTCA), western blot, real-time quantitative PCR (RT-qPCR), immunofluorescence and pathological staining.

Results

LAP and tLAP could inhibit TGF-β1-induced AML12 cells inflammation, apoptosis and EMT, and could inhibit TGF-β1-induced HSC-T6 cells proliferation and fibrosis. LAP and tLAP could attenuate the pathological changes of liver fibrosis and inhibit the expression of fibrosis-related proteins and mRNAs in CCl₄-induced liver fibrosis mice.

Conclusion

LAP and tLAP could alleviate liver fibrosis in vitro and in vivo via inhibition of TGF-β/Smad pathway. TLAP has higher expression level and more effective anti-fibrosis activity compared to LAP. This study may provide new ideas for the treatment of liver fibrosis.

Metabolomic Profiling for Histologically Fibrotic Stage in Chronic Drug-Induced Liver Injury

Background and aims: Chronic drug-induced liver injury (DILI) is a rare but under-researched adverse drug reaction–related disease, which is highly likely to progress into liver fibrosis and even cirrhosis. In this study, metabolomics was used to screen out characteristic metabolites related to the histological progression of fibrosis in chronic DILI and analyze the metabolic changes during the development of fibrosis to explain the underlying mechanism.

Methods: Chronic DILI patients who underwent liver biopsy were divided into different fibrosis grades. Serum was analyzed by untargeted metabolomics to find serological characteristic metabolite fingerprints. The screened fingerprints were validated by the validation group patients, and the identification ability of fingerprints was compared using FibroScan.

Results: A total of 31 metabolites associated with fibrosis and 11 metabolites associated with advanced fibrosis were identified. The validation group confirmed the accuracy of the two metabolite fingerprints [area under the curve (AUC) value 0.753 and 0.944]. In addition, the fingerprints showed the ability to distinguish the grades of fibrosis by comparing using FibroScan. The metabolite fingerprint pathway showed that bile acid synthesis is disturbed while lipid metabolism is extremely active, resulting in an overload of lipid metabolites in the occurrence and development of chronic DILI–associated fibrosis.

Conclusions: Our metabolomic analysis reveals the unique metabolomic fingerprints associated with chronic DILI fibrosis, which have potential clinical diagnostic and prognostic significances. The metabolomic fingerprints suggest the disturbance of the lipid metabolites as the most important factor in the development of DILI fibrosis.

Overexpression of ring finger protein 20 inhibits the progression of liver fibrosis via mediation of histone H2B lysine 120 ubiquitination

Liver fibrosis is a chronic liver injury that leads to liver cirrhosis and liver cancer. Ring finger protein 20 (RNF20), also named as E3 ubiquitin-protein ligase BRE1A, has been reported to be involved in chronic liver diseases. However, the role of RNF20 in liver fibrosis remains unclear. To mimic liver fibrosis in vitro, LX-2 cells were treated with TGF-β. Gene and protein expressions were detected by RT-qPCR and western blot, respectively. The mechanism by which RNF20 mediated the progression of liver fibrosis was explored by bioinformatics analysis. Finally, in vivo mouse model of liver fibrosis was established to detect the function of RNF20. The results indicated that TGF-β-induced increase of cell viability and migration was significantly reversed by RNF20 overexpression. Consistently, overexpression of RNF20 significantly reversed TGF-β-induced activation of fibrotic proteins in LX-2 cells. Meanwhile, VEGFA, TNF-α and IL-6 were found to be the downstream targets of RNF20 in LX-2 cells. Moreover, RNF20 overexpression notably inhibited the progression of liver fibrosis via ubiquitination of H2B. Finally, RNF20 upregulation significantly attenuated the symptom of liver fibrosis in vivo. In summary, overexpression of RNF20 significantly inhibited the progression of liver fibrosis in vitro and in vivo. Therefore, RNF20 might serve as a new target for the treatment of liver fibrosis.