Pulmonary fibrosis (PF) can severely disrupt lung function, leading to fatal consequences. Salidroside is a principal active ingredient of Rhodiola rosea and has recently been reported to protect against lung injures. The present study was aimed at exploring its therapeutic effects on PF. Lung fibrotic injuries were induced in SD rats by a single intratracheal instillation of 5 mg/kg bleomycin (BLM). Then, these rats were administrated with 50, 100, or 200 mg/kg salidroside for 28 days. BLM-triggered structure distortion, collagen overproduction, excessive inflammatory infiltration, and pro-inflammatory cytokine release, and oxidative stress damages in lung tissues were attenuated by salidroside in a dose-dependent manner. Furthermore, salidroside was noted to inhibit IκBα phosphorylation and nuclear factor kappa B (NF-κB) p65 nuclear accumulation while activating Nrf2-antioxidant signaling in BLM-treated lungs. Downregulation of E-cadherin and upregulation of vimentin, fibronectin, and α-smooth muscle actin (α-SMA) indicated an epithelial-mesenchymal transition (EMT)-like shift in BLM-treated lungs. These changes were suppressed by salidroside. The expression of TGF-β1 and the phosphorylation of its downstream targets, Smad-2/-3, were enhanced by BLM, but weakened by salidroside. Additionally, salidroside was capable of reversing the recombinant TGF-β1-induced EMT-like changes in alveolar epithelial cells in vitro. Our study reveals that salidroside’s protective effects against fibrotic lung injuries are correlated to its anti-inflammatory, antioxidative, and antifibrotic properties.

The profibrotic cytokine transforming growth factor-β1 (TGF-β1) causes renal fibrosis by binding to receptors at the cell surface; however, it is not clear which of the TGF-β superfamily receptors correlates with renal fibrosis. To resolve this, we quantified TGF-β superfamily receptor expression in the kidneys of rats with unilateral ureteral obstruction using a real-time PCR gene array. Expression of activin receptor-like kinase (ALK)-5, ALK7, and TGF-β receptor II (TGF-βRII) mRNA increased significantly, while ALK6 mRNA expression was significantly decreased in the obstructed rat kidney. Core fucosylation is essential for the proper function of both TGF-βRII and ALK5 in cultured human renal proximal tubular epithelial cells in vitro. Therefore, we targeted posttranslational core fucosylation, regulated by α-1,6 fucosyltransferase (FUT8), by adenoviral-mediated knockdown of FUT8 mRNA in vivo and measured TGF-βRII and ALK5 expression and the progression of renal fibrosis. Despite long-term obstruction injury, inhibition of TGF-βRII and ALK5 of core fucosylation ameliorated the progression of renal fibrosis, an effect independent of TGF-βRII and ALK5 expression. Thus, the regulation of TGF-β1-receptor core fucosylation may provide a novel potential therapeutic strategy for treating renal fibrosis.

Idiopathic pulmonary fibrosis is a chronic and progressive fibrotic lung disorder with unknown etiology and a high mortality rate. Tanshinone ⅡA (Tan ⅡA) is a lipophilic diterpene extracted from the Chinese herb Salvia miltiorrhiza Bunge with diverse biological functions. The present study was conducted to evaluate the effects of Tan ⅡA on bleomycin (BLM)‑induced pulmonary fibrosis in rats. Rats received an intraperitoneal injection of Tan ⅡA and normal rats were used as controls. Severe pulmonary edema, inflammation and fibrosis were observed in the BLM‑treated rats and the counts of total cells, neutrophils and lymphocytes were significantly increased in the bronchoalveolar lavage fluids of those rats. These pathological changes were markedly attenuated by subsequent treatment with Tan ⅡA. In addition, BLM‑induced increased expression of tumor necrosis factor‑α, interleukin (IL)‑1β, IL‑6, cyclooxygenase‑2, prostaglandin E2, malondialdehyde, inducible nitric oxide synthase and nitric oxide in rats, which was also suppressed by Tan ⅡA injection. The present findings suggest therapeutic potential of Tan ⅡA for pulmonary fibrosis.

Pericytes have been identified as a major source of myofibroblasts in renal interstitial fibrosis (RIF). The overactivation of several signaling pathways, mainly the TGF-β and PDGF pathways, initiates the pericyte-myofibroblast transition during RIF. Key receptors in these two pathways have been shown to be modified by fucosyltransferase 8 (FUT8), the enzyme that catalyzes core fucosylation. This study postulated that core fucosylation might play an important role in regulating the pericyte transition in RIF. The data showed that core fucosylation increased with the extent of RIF in patients with IgA nephropathy (IgAN). Similarly, core fucosylation of pericytes increased in both a unilateral ureteral occlusion (UUO) mouse model and an in vitro model of pericyte transition. Inhibition of core fucosylation by adenoviral-mediated FUT8 shRNA in vivo and FUT8 siRNA in vitro significantly reduced pericyte transition and RIF. In addition, the activation of both the TGF-β/Smad and PDGF/ERK pathways was blocked by core fucosylation inhibition. In conclusion, core fucosylation may regulate the pericyte transition in RIF by modifying both the TGF-β/Smad and PDGF/ERK pathways. Glycosylation might be a novel “hub” target to prevent RIF.

Renal interstitial fibrosis (RIF) is an incurable pathological lesion in chronic kidney diseases. Pericyte activation is the major pathological characteristic of RIF. Fibroblast and macrophage activation are also involved in RIF. Studies have revealed that core fucosylation (CF), an important post-translational modification of proteins, plays a key role in pericyte activation and RIF by regulating multiple profibrotic signaling pathways as a hub-like target. Here, we reveal that mesenchymal stem cell (MSC)-derived exosomes reside specifically in the injured kidney and deliver microRNA (miR)-34c-5p to reduce cellular activation and RIF by inhibiting CF. Furthermore, we showed that the CD81-epidermal growth factor receptor (EGFR) ligand-receptor complex aids the entry of exosomal miR-34c-5p into pericytes, fibroblasts, and macrophages. Altogether, our findings reveal a novel role of MSC-derived exosomes in inhibiting multicellular activation via CF and provide a potential intervention strategy for renal fibrosis.

Idiopathic pulmonary fibrosis is a progressive and lethal form of interstitial lung disease that lacks effective therapies at present. Glycyrrhizic acid (GA), a natural compound extracted from a traditional Chinese herbal medicine Glycyrrhiza glabra, was recently reported to benefit lung injury and liver fibrosis in animal models, yet whether GA has a therapeutic effect on pulmonary fibrosis is unknown. In this study, we investigated the potential therapeutic effect of GA on pulmonary fibrosis in a rat model with bleomycin (BLM)-induced pulmonary fibrosis. The results indicated that GA treatment remarkably ameliorated BLM-induced pulmonary fibrosis and attenuated BLM-induced inflammation, oxidative stress, epithelial-mesenchymal transition and activation of tansforming growth factor-beta signaling pathway in the lungs. Further, we demonstrated that GA treatment inhibited proliferation of 3T6 fibroblast cells, induced cell cycle arrest and promoted apoptosis in vitro, implying that GA-mediated suppression of fibroproliferation may contribute to the anti-fibrotic effect against BLM-induced pulmonary fibrosis. In summary, our study suggests a therapeutic potential of GA in the treatment of pulmonary fibrosis.