MARCH8 downregulation modulates profibrotic responses including myofibroblast differentiation.

Interstitial lung diseases can result in poor patient outcomes, especially in idiopathic pulmonary fibrosis (IPF), a severe interstitial lung disease with unknown causes. The lack of treatment options requires further understanding of the pathological process/mediators. Membrane-associated RING-CH 8 (MARCH8) has been implicated in immune function regulation and inflammation, however, its role in the development of pulmonary fibrosis and particularly the fibroblast to myofibroblast transition (FMT) remains a gap in existing knowledge. In this study, we demonstrated decreased MARCH8 expression in patients with IPF compared with non-PF controls and in bleomycin-induced PF. TGF-ß dose- and time-dependently decreased MARCH8 expression in normal and IPF human lung fibroblast (HLFs), along with induction of FMT markers α-SMA, collagen type I (Col-1), and fibronectin (FN). Interestingly, overexpression of MARCH8 significantly suppressed TGF-ß-induced expression of α-SMA, Col-1, and FN. By contrast, the knockdown of MARCH8 using siRNA upregulated basal expression of α-SMA/Col-1/FN. Moreover, MARCH8 knockdown enhanced TGF-ß-induced FMT marker expression. These data clearly show that MARCH8 is a critical "brake" for FMT and potentially affects PF. We further found that TGF-ß suppressed MARCH8 mRNA expression and the proteasome inhibitor MG132 failed to block MARCH8 decrease induced by TGF-ß. Conversely, TGF-ß decreases mRNA levels of MARCH8 in a dose- and time-dependent manner, suggesting the transcriptional regulation of MARCH8 by TGF-ß. Mechanistically, MARCH8 overexpression suppressed TGF-ß-induced Smad2/3 phosphorylation, which may account for the observed effects. Taken together, this study demonstrated an unrecognized role of MARCH8 in negatively regulating FMT and profibrogenic responses relevant to interstitial lung diseases.NEW & NOTEWORTHY MARCH8 is an important modulator of inflammation, immunity, and other cellular processes. We found that MARCH8 expression is downregulated in the lungs of patients with idiopathic pulmonary fibrosis (IPF) and experimental models of pulmonary fibrosis. Furthermore, TGF-ß1 decreases MARCH8 transcriptionally in human lung fibroblasts (HLFs). MARCH8 overexpression blunts TGF-ß1-induced fibroblast to myofibroblast transition while knockdown of MARCH8 drives this profibrotic change in HLFs. The findings support further exploration of MARCH8 as a novel target in IPF.

DOCK2 contributes to pulmonary fibrosis by promoting lung fibroblast to myofibroblast transition.

Idiopathic pulmonary fibrosis (IPF) is the most common chronic interstitial lung disease and is characterized by progressive scarring of the lung. Transforming growth factor-ß (TGF-ß) signaling plays an essential role in IPF and drives fibroblast to myofibroblast transition (FMT). Dedicator of cytokinesis 2 (DOCK2) is known to regulate diverse immune functions by activating Rac and has been recently implicated in pleural fibrosis. We now report a novel role of DOCK2 in pulmonary fibrosis development by mediating FMT. In primary normal and IPF human lung fibroblasts (HLFs), TGF-ß induced DOCK2 expression concurrent with FMT markers, smooth muscle α-actin (α-SMA), collagen-1, and fibronectin. Knockdown of DOCK2 significantly attenuated TGF-ß-induced expression of these FMT markers. In addition, we found that the upregulation of DOCK2 by TGF-ß is dependent on both Smad3 and ERK pathways as their respective inhibitors blocked TGF-ß-mediated induction. TGF-ß also stabilized DOCK2 protein, which contributes to increased DOCK2 expression. In addition, DOCK2 was also dramatically induced in the lungs of patients with IPF and in bleomycin, and TGF-ß induced pulmonary fibrosis in C57BL/6 mice. Furthermore, increased lung DOCK2 expression colocalized with the FMT marker α-SMA in the bleomycin-induced pulmonary fibrosis model, implicating DOCK2 in the regulation of lung fibroblast phenotypic changes. Importantly, DOCK2 deficiency also attenuated bleomycin-induced pulmonary fibrosis and α-SMA expression. Taken together, our study demonstrates a novel role of DOCK2 in pulmonary fibrosis by modulating FMT and suggests that targeting DOCK2 may present a potential therapeutic strategy for the prevention or treatment of IPF.

Mitigative effect of Momordica cymbalaria fruit extract against sodium fluoride induced hepatotoxicity in Wistar male albino rats.

OBJECTIVES: The main objective of the present study is to evaluate the mitigative effect of hydroalcoholic extract of Momordica cymbalaria fruits against sodium fluoride (NaF) induced hepatotoxicity. METHODS: In this study, Wistar male albino rats were randomly divided into five groups of six rats each. Group I and II served as normal and toxic controls. Group III as plant control received extract at a dose of 400 mg/kg b. wt, p.o and Groups IV and V as treatment groups received extract at a dose 200 and 400 mg/kg b. wt, p.o for 30 days. All groups except Groups I and III received 100 ppm of NaF through drinking water. After completion of the study, blood collected for the estimation of liver blood serum biomarkers such as aspartate aminotransferases (AST), alanine aminotransferases (ALT), alkaline Phosphatase (ALP), direct and total bilirubin, total protein and albumin. The liver tissue homogenate was for estimation of lipid peroxidation, catalase, and reduced glutathione levels. RESULTS: The results showed that NaF intoxication caused elevation of liver blood serum levels and lipid peroxidation; decreased levels of serum total protein, albumin and liver reduced glutathione, and catalase observed. The treatment groups showed decreased elevated serum biomarkers (ALT, AST, and ALP), liver lipid peroxidation and increased serum total protein and albumin, liver reduced glutathione and catalase levels in a dose-dependent manner. Histopathological studies also further strongly supported for mitigative effects of the plant. CONCLUSIONS: In conclusion, our findings of the study indicated that M. cymbalaria fruits were a potential drug candidate in the treatment of NaF induced hepatotoxicity.