Tanshinone IIA ameliorates bleomycin-induced pulmonary fibrosis and inhibits transforming growth factor-beta-β-dependent epithelial to mesenchymal transition.

Epithelial to mesenchymal transition (EMT) of alveolar epithelial cells occurs in lung fibrotic diseases. Tanshinone IIA (Tan IIA) has been reported to exert anti-inflammatory effects in pulmonary fibrosis. Nonetheless, whether Tan IIA affects lung fibrosis-related EMT remains unknown and requires for further investigations. A single intratracheal instillation of saline containing bleomycin (BLM; 5 mg/kg body weight) was performed to induce pulmonary fibrosis in Sprague-Dawley rats. Rats receiving an instillation of equivoluminal normal saline served as controls. Then, these rats were given a daily intraperitoneal administration of Tan IIA (15 mg/kg body weight) for 28 d before sacrifice. In vitro, recombinant transforming growth factor-beta 1 (TGF-β1; 10 ng/mL) was used to treat human alveolar epithelial A549 cells for 48 h. Tan IIA (10 μM) or control DMSO was used to pretreat cells for 2 h before TGF-β1 stimulation. Rat lung tissue samples and A549 cells were then subjected to further assessments. Tan IIA was noted to alleviate BLM-induced pulmonary collagen deposition and macrophage infiltration in rats. Epithelial-cadherin expression was decreased after BLM stimulation, whereas α-smooth muscle actin, fibronectin, and vimentin were increased. These expression alterations were partially reversed by Tan IIA. Moreover, Tan IIA suppressed BLM-induced increases in TGF-β1, phosphorylated Smad-2, and -3 in rats. Additionally, pretreatment of Tan IIA inhibited TGF-β1-triggered EMT, reduced collagen Ⅰ production, and blocked TGF-β signal transduction in A549 cells. Our research suggests that Tan IIA mitigates BLM-induced pulmonary fibrosis and suppresses TGF-β-dependent EMT of lung alveolar epithelial cells.

Tang H ，He H ，Ji H ，Gao L ，Mao J ，Liu J ，Lin H ，Wu T ... -  《-》

Tanshinone IIA attenuates silica-induced pulmonary fibrosis via Nrf2-mediated inhibition of EMT and TGF-β1/Smad signaling.

Silicosis is an occupational pulmonary fibrosis that is caused by inhalation of silica (SiO2), and there are no effective drugs to treat this disease. Tanshinone IIA (Tan IIA), a natural product, has been reported to possess antioxidant and anti-fibrotic properties in various diseases. The purpose of the current study was to examine Tan IIA's protective effects against silica-induced pulmonary fibrosis and to explore the underlying mechanisms. We found that in vivo treatment with Tan IIA significantly relieved silica-induced lung fibrosis in a silicosis rat model by histological and immunohistochemical analyses. Further, in vitro mechanistic investigations, mainly using western blot and immunofluorescence analyses, revealed that Tan IIA administration markedly inhibited the silica-induced epithelial-mesenchymal transition (EMT) and transforming growth factor-β1 (TGF-β1)/Smad signaling pathway and also reduced silica-induced oxidative stress and activated the nuclear factor erythroid 2-related factor-2 (Nrf2) signaling pathway in A549 and human bronchial epithelial (HBE) cells. Furthermore, through transfection with siRNA, we demonstrate that Nrf2 activation partially mediates the suppression effects of Tan IIA on EMT and TGF-β1/Smad signaling pathway activation induced by silica exposure, thus mediating the anti-fibrotic effects of Tan IIA against silica-induced pulmonary fibrosis. In our study, Tan IIA has been identified as a possible anti-oxidative and anti-fibrotic drug for silicosis.

Feng F ，Cheng P ，Xu S ，Li N ，Wang H ，Zhang Y ，Wang W ... -  《-》

Paeoniflorin suppresses TGF-β mediated epithelial-mesenchymal transition in pulmonary fibrosis through a Smad-dependent pathway.

Ji Y ，Dou YN ，Zhao QW ，Zhang JZ ，Yang Y ，Wang T ，Xia YF ，Dai Y ，Wei ZF ... -  《-》

High-Mobility Group Box 1 Mediates Epithelial-to-Mesenchymal Transition in Pulmonary Fibrosis Involving Transforming Growth Factor-β1/Smad2/3 Signaling.

Epithelial-to-mesenchymal transition (EMT) is a crucial event in the cellular origin of myofibroblasts that secrete extracellular matrix in the progression of pulmonary fibrosis (PF). High-mobility group box 1 (HMGB1) is a novel mediator of EMT. However, whether this process involves the recognized transforming growth factor-β1 (TGF-β1)/Smad signaling that also contributes to EMT in PF has not yet been elucidated. Here, we developed a model of PF induced by bleomycin (BLM) in rats and conducted several simulation experiments in A549 (human) and RLE-6TN (rat) alveolar epithelial cell (AEC) lines to unravel the role of TGF-β1/Smad2/3 signaling in HMGB1-mediated EMT. We found that the levels of serum HMGB1 and lung hydroxyproline were severely elevated after BLM administration. Moreover, the protein expression of HMGB1, TGF-β1, phosphorylated Smad2/3 (p-Smad2/3), and mesenchymal markers including α-smooth muscle actin, vimentin, and type I collagen were significantly increased with the reduced protein expression of an epithelial marker (E-cadherin) in the rat model by Western blot or immunohistochemical analysis. In addition, the uptake of both exogenous TGF-β1 and HMGB1 by AECs could induce EMT; meanwhile, HMGB1 dramatically enhanced TGF-β1 expression and triggered Smad2/3 phosphorylation. In contrast, TGF-β1 deficiency evidently ameliorated HMGB1-mediated EMT with reduced p-Smad2/3 in A549 cells. It provides new insights that HMGB1 release from injured lungs promotes AEC damage through induction of the EMT process, in which TGF-β1/Smad2/3 signaling is activated and contributes to PF. These results suggest that HMGB1 may constitute a therapeutic target for developing antifibrotic agents for abnormal lung remodeling.

Li LC ，Li DL ，Xu L ，Mo XT ，Cui WH ，Zhao P ，Zhou WC ，Gao J ，Li J ... -  《-》

[Effects of andrographolide on the concentration of cytokines in BALF and the expressions of type I and III collagen mRNA in lung tissue in bleomycin-induced rat pulmonary fibrosis].

Zhu HL ，Huang CL ，Wang WJ ，Zhan XQ ，Fan XM ... -  《-》