Ligustrazin increases lung cell autophagy and ameliorates paraquat-induced pulmonary fibrosis by inhibiting PI3K/Akt/mTOR and hedgehog signalling via increasing miR-193a expression

Abstract

BackgroundReactive oxygen species (ROS) levels largely determine pulmonary fibrosis. Antioxidants have been found to ameliorate lung fibrosis after long-term paraquat (PQ) exposure. The effects of antioxidants, however, on the signalling pathways involved in PQ-induced lung fibrosis have not yet been investigated sufficiently. Here, we examined the impacts of ligustrazin on lung fibrosis, in particular ROS-related autophagy and pro-fibrotic signalling pathways, using a murine model of PQ-induced lung fibrosis.MethodsWe explored the effects of microRNA-193 (miR-193a) on Hedgehog (Hh) and PI3K/Akt/mTOR signalling and oxidative stress in lung tissues. Levels of miR-193a, protein kinase B (Akt), phosphoinositide 3-Kinase (PI3K), ceclin1, mammalian target of rapamycin (mTOR), sonic hedgehog (SHH), myosin-like Bcl2 interacting protein (LC3), smoothened (Smo), and glioma-associated oncogene-1 (Gli-1) mRNAs were determined with quantitative real-time PCR. Protein levels of PI3K, p-mTOR, p-Akt, SHH, beclin1, gGli-1, LC3, smo, transforming growth factor-β1 (TGF-β1), mothers against DPP homologue-2 (Smad2), connective tissue growth factor (CTGF), collagen I, collagen III, α-smooth muscle actin (α-SMA) nuclear factor erythroid 2p45-related factor-2 (Nrf2), and p-Smad2 were detected by western blotting. In addition, α-SMA, malondialdehyde, ROS, superoxide dismutase (SOD), oxidised and reduced glutathione, hydroxyproline, and overall collagen levels were identified in lung tissues using immunohistochemistry.ResultsLong-term PQ exposure blocked miR-193a expression, reduced PI3K/Akt/mTOR signalling, increased oxidative stress, inhibited autophagy, increased Hh signalling, and facilitated the formation of pulmonary fibrosis. Ligustrazin blocked PI3K/Akt/mTOR and Hh signalling as well as reduced oxidative stress via increasing miR-193a expression and autophagy, all of which reduced pulmonary fibrosis. These effects of ligustrazin were accompanied by reduced TGF-β1, CTGF, and Collagen I and III expression.ConclusionsLigustrazin blocked PQ-induced PI3K/Akt/mTOR and Hh signalling by increasing miR-193a expression, thereby attenuating PQ-induced lung fibrosis.

MicroRNA and ROS Crosstalk in Cardiac and Pulmonary Diseases

“…Using the PQ-induced PF model, Liu et al showed that ligustrazine, an antioxidant extracted from the roots and stems of Ligusticum chuanxiong Hort (Chuan Xiong) ameliorates lung fibrosis by inactivating the AKT/mTOR and hedgehog signaling pathway through upregulation of miR-193a, leading to increased cell autophagy and reduced fibrosis. This study demonstrated that miR-193a mediates the antioxidant protective effect of ligustrazine in pulmonary fibrosis [117].…”

Self-eating: friend or foe? The emerging role of autophagy in fibrotic diseases

“…A recent study has suggested that LKB1-AMPK-ULK1 axis-mediated autophagy plays a critical role in the BLM-induced lung fibrosis 111 . Several studies have shown that several antioxidant agents and bioactive natural products, such as coenzyme Q 10 (CoQ10), celastrol and ligustrazin, promoted autophagy, reduced expression of TGF-β and Col-1 and protected against different chemical compounds-induced IPF through the downregulation of the PI3K/Akt/mTOR pathways in animal models 112 - 114 . Du et al further suggested that dioscin activated autophagy, reduced the secretion of inflammatory factors and subsequently alleviated the abnormal collagen accumulation.…”

lncRNA ZFAS1 promotes lung fibroblast-to-myofibroblast transition and ferroptosis via functioning as a ceRNA through miR-150-5p/SLC38A1 axis

“…For example, upregulation of GPX4 decreased myofibroblast differentiation, ROS levels and ferroptosis in the TGF-β1-induced PF cell model [21]. Furthermore, increasing evidence has confirmed that glutamine metabolism contributes to the formation of oxidizable lipids, which could lead to ferroptosis [22,23], and the level of glutathione in PF lung tissues was downregulated [24,25]. In addition, SLC38A1 is an important regulator of glutamine uptake and metabolism in lipid peroxidation [26].…”