Plumbagin attenuates traumatic tracheal stenosis in rats and inhibits lung fibroblast proliferation and differentiation via TGF-β1/Smad and Akt/mTOR pathways

Abstract

Traumatic tracheal stenosis (TS) is a serious respiratory disease characterized by hyperplasia of airway granulation. Plumbagin (PLB) is a natural naphthoquinone component with anti-fibrotic properties. This research aimed to explore the roles of PLB in alleviating TS and the underlying mechanisms. For in vitro studies, lung fibroblasts (IMR-90 cells), with/without PLB treatment or TGF-β1 induction, were used. The viability and proliferation of IMR-90 cells were examined by CCK-8 and EdU incorporation assays. The differentiation of IMR-90 cells was assessed by detecting the mRNA and protein expression levels of collagen (COL)-1 and alpha-smooth muscle actin (α-SMA). Besides, immunofluorescence assay was conducted to evaluate the localization of α-SMA in TGF-β1-induced IMR-90 cells. Moreover, the combination of PLB with/without TβRI (SB-431,542), PI3K/Akt (Ly294002) or mTOR (rapamycin) inhibitor was pretreated on IMR-90 cells after TGF-β1 induction. For in vivo studies, a rat model of TS was established. The pathological features and severity of TS were determined by hematoxylin and eosin staining. The protein levels of TGF-β1/Smad and Akt/mTOR pathways were detected for both in vitro and in vivo models. PLB effectively inhibited the proliferation and differentiation of TGF-β1-induced IMR-90 cells, and suppressed TGF-β1/Smad and Akt/mTOR signaling pathways both in vivo and in vitro. Furthermore, PLB reduced the degree of TS in rats. Taken together, our results indicate that PLB regulates lung fibroblast activity and attenuates TS in rats by inhibiting TGF-β1/Smad and Akt/mTOR signaling pathways. In conclusion, this study implies that PLB may serve as a promising therapeutic compound for TS.

Differential expression of miRNAs revealed by small RNA sequencing in traumatic tracheal stenosis

“…Among them, inflammatory signaling pathways such as TNF, NF-κB, and toll-like receptor signaling pathways; fibrosis signaling pathways such as MAPK, JAK-STAT, Ras, Rap1, Notch, and Wnt signaling pathways; and PI3K-Akt, mTOR, HIF-1, and PPAR signaling pathways were found to be enriched. These results indicate the important role of inflammation and fibrosis in TTS development, which is consistent with the studies by Xiao et al (2020 ), Fan et al (2021 ), and SHI et al (2021 ).…”

Distribution and chemotactic mechanism of CD4+ T cells in traumatic tracheal stenosis

“…This research proved a strong correlation between the secretion of TGF‐β1 and the number of these two immune cell subtypes, indicating that immune cells may be crucial in the onset and progression of TS through aberrant secretion of TGF‐β1 and other cytokines. Previous reports on TS fibrosis have mainly focused on the TGF‐β1 pathway 46–48 . Therefore, this paper discussed the new possibility that the imbalance of immune cells and the secretion of cytokines may affect the occurrence and development of TS.…”

“…Previous reports on TS fibrosis have mainly focused on the TGF‐β1 pathway. 46 , 47 , 48 Therefore, this paper discussed the new possibility that the imbalance of immune cells and the secretion of cytokines may affect the occurrence and development of TS. At present, studies have constantly explored the potential of immune cells as targeted therapies.…”

miR-34c-5p inhibited fibroblast proliferation, differentiation and epithelial-mesenchymal transition in benign airway stenosis via MDMX/p53 pathway

“…(Karagiannidis, et al 2006 ). Previous studies have suggested that the genesis and progression of BAS are caused by airway mucosal inflammation, mucosal abnormal hyperplasia, epithelial-mesenchymal transition (EMT) and fibrous scar formation under the influence of various factors, such as infection, trauma and hypoxia, which leads to stenosis (Shi, et al 2021 ; Wu, et al 2021 ; Wei, et al 2023 ). Owing to the action of cytokines like transforming growth factor-β1 (TGF-β1) following BAS, tracheobronchial fibroblasts aberrantly aggregate and proliferate, which results in the proliferation of granulation tissues and fibrosis (Wu, et al 2021 ; Xu, et al 2021 ).…”