Mefunidone Ameliorates Bleomycin-Induced Pulmonary Fibrosis in Mice

Abstract

Idiopathic pulmonary fibrosis (IPF) is one of the most common and devastating interstitial lung diseases with poor prognosis. Currently, few effective drugs are available for IPF. Hence, we sought to explore the role of mefunidone (MFD), a newly synthesized drug developed by our team, in lung fibrosis. In this study, MFD was found to attenuate bleomycin (BLM) -induced lung fibrosis and inflammation in mice according to Ashcroft and alveolitis scoring. The protein contents and total cell counts in bronchoalveolar lavage fluids of BLM-treated mice were also lowered by MFD. Moreover, the elevation of TGF-β/Smad2 and phosphorylation of MAPK pathways was repressed by MFD. Additionally, MFD attenuated the swelling and vacuolization of mitochondria, lowered the ratio of apoptotic cells, restored the mitochondrial membrane potential, and reversed the expression of cleaved-caspase 3, Bcl-2 and Bax. Meanwhile, the level of epithelial marker, E-cadherin, was restored by MFD, while the levels of mesenchymal markers such as Snail and vimentin were down-regulated by MFD. Besides, MFD inhibited the expression of fibronectin and α-smooth muscle actin in TGF-β treated normal human lung fibroblasts. Thus, our findings suggested that MFD could ameliorate lung fibrosis, cell apoptosis and EMT potentially via suppression of TGF-β/Smad2 and MAPK pathways.

The mitigating effect of para‐hydroxycinnamic acid in bleomycin‐induced pulmonary fibrosis in mice through targeting oxidative, inflammatory and fibrotic pathways

“…32 These findings can explain the results of the tissue homogenate level of TGF-β1 and the expression of Smad3 by immunostaining, where animals of the induced group (received BLM only) expressed a marked elevation in the profibrotic cytokine (TGF-β1) and Smad3 (Figure 4A,E) as a result of the direct damage to the AECs and the excessive production of reactive oxygen species (ROS), which was supported by previous studies. 32,41,50 The animals that received treatment with P-HCA and PFD had similar effects, as evidenced by the suppression of Smad3 expression. This improvement in the level of TGF-β1 and the expression of Smad3 protein, which is the important intracellular signalling pathway for the final gene expression of necessary fibrotic markers, can be explained as follows: (1) their anti-inflammatory effect by reducing the synthesis and production of important cytokines involved in PF, through reducing the expression of NF-κB and its activated signalling pathways, the inflammasome (NLRP3) as demonstrated by the results of the lung tissue gene expression of NF-κB (Figure 7C) and NLRP3 (Figure 7D); (2) their antioxidant activity, which further contributes to the reduced production of proinflammatory and pro-fibrotic cytokines either by direct scavenging of ROS or through modulating the expression of antioxidant genes by increasing the expression and activity of the nuclear regulatory factor (Nrf2) as explained earlier and observed by different previous studies 51,52 ; (3) this effect could be either due to direct inhibition of TGF-β1 binding to its receptor or inhibiting the signalling pathway (Smad3), thus interfering with the TGF-β1/Smad3 signalling, which is necessary for fibroblast proliferation, differentiation into myoblast, mesenchymal transitioning and finally production of ECM.…”

“…The cell exhibited a brown colouration. 32 The sections were observed by light microscope and photographed to estimate the expression of Smad3, fibronectin, vimentin and α-SMA proteins. A semiquantitative scoring was used to evaluate the expression of the selected markers in the immuno-stained sections, and this was done by a pathologist blinded to the experimental groups.…”

Systematic Analysis Strategy Based on Network Pharmacology to Investigate the Potential Mechanism of Fritillaria thunbergii Miq. against Idiopathic Pulmonary Fibrosis

“…TGF- β -induced epithelial-mesenchymal transition (EMT) is dependent on the activation of the MAPK signaling cascade [ 60 ]. Mefunidone was shown to reduce the expression of Snail and vimentin by inhibiting the transduction of the TGF- β /Smad2 signaling pathway and the activation of the MAPK pathway, thereby inhibiting the process of EMT and improving pulmonary fibrosis [ 61 ]. In our study, MAPK1 (ERK2) and MAPK3 (ERK1) were enriched.…”

Berberine regulates pulmonary inflammatory microenvironment and decreases collagen deposition in response to bleomycin‐induced pulmonary fibrosis in mice

“…Alveolar counts, areas, area percentages and circumferences were evaluated using Image‐Pro Plus 6.0. Moreover, double‐blind scoring was performed for the evaluation of tissue inflammation and tissue fibrosis based on the following scale: Tissue inflammation 24 : 0 = the absence of tissue inflammation; 1 = random distribution of inflammatory cells; 2 = inflammatory cells surrounding most of the bronchi and veins by a thin layer (thickness of one to five cells); 3 = inflammatory cells surrounding most of the bronchi and veins by a thick layer (a thickness of >5 cells); and 4 = complete pulmonary inflammation around all veins and bronchi. Tissue fibrosis 25 : 0 = normal pulmonary tissue; 1 = minimal thickness in alveoli and bronchial walls; 2–3 = medium thickness in alveoli and bronchial walls without significant damage to the lung structure; 4–5 = increase in fibrosis with significant damage to the lung structure and formation of small clumps of fibrotic tissue; 6–7 = severe destruction of the structure, large areas of fibrosis and presence of “honeycomb lung”; and 8 = total pulmonary fibrosis. …”