Exogenous H2S donor, sodium hydrosulfide (NaHS), can influence the bleomycin‐induced pulmonary fibrosis by attenuating the epithelial‐mesenchymal transition (EMT) of alveolar epithelial cells, but whether NaHS affects paraquat (PQ)‐induced EMT and the molecular mechanisms remain unclarified. The aim of the present study is to examine the effect of exogenous NaHS on PQ‐induced EMT in human alveolar epithelial cells (A549 cells) and assess if this effect occurs through regulating transforming growth factor (TGF)‐β1/Smad2/3 signaling pathway. The expressions of endogenous H2S producing enzymes, namely cystathionine β‐synthase, cystathionine γ‐lyase and 3‐mercaptopyruvate sulfur transferase, were detected by reverse transcription‐polymerase chain reaction and western blotting. The induced EMT was assessed by morphological and phenotypic characterizations, and the protein level of E‐cadherin and vimentin were detected by western blotting. To investigate the effect of NaHS on PQ‐induced EMT and potential mechanism, A549 cells were pretreated with NaHS before incubating with PQ and then evaluated by morphological changes, cell migration ability, the expression of EMT markers and TGF‐β1/Smad2/3 signaling pathway related proteins. PQ significantly downregulated the expression levels of cystathionine β‐synthase and cystathionine γ‐lyase, but not 3‐mercaptopyruvate sulfur transferase, in a time‐dependent manner in A549 cells. Exogenous NaHS could significantly retard PQ‐induced morphological changes and cell migration ability. Furthermore, exogenous NaHS significantly upregulated the expression of E‐cadherin, whereas it downregulated the expression of vimentin. In addition, exogenous NaHS could also significantly attenuates PQ‐induced TGF‐β1, phosphorylated Smad2/3 proteins expression, which induced by PQ in a time‐dependent manner. This study provides the first evidence that exogenous NaHS attenuates PQ‐induced EMT and migration of human alveolar epithelial cells through regulating the TGF‐β1/Smad2/3 signaling pathway.

The lysine crotonylation of histone proteins is a newly identified posttranslational modification with diversified cellular functions. However, there are few reports on lysine crotonylation of non-histone proteins in medicinal plant cells. By using high-resolution liquid chromatography–mass spectrometry (LC-MS) coupled with highly sensitive-specific immune-affinity antibody analysis, a whole crotonylation proteome analysis of Dendrobium huoshanense was performed. In total, 1,591 proteins with 4,726 lysine crotonylation sites were identified; among them, 11 conserved motifs were identified. Bioinformatic analyses linked crotonylated proteins to the drought stress response and multiple metabolic pathways, including secondary metabolite biosynthesis, transport and catabolism, energy production and conversion, carbohydrate transport and metabolism, translation, and ribosomal structure and biogenesis. This study contributes toward understanding the regulatory mechanism of polysaccharide biosynthesis at the crotonylation level even under abiotic stress.

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Dendrobium huoshanense C. Z. Tang et S. J. Cheng polysaccharide (DHP) is the essential active ingredient of D.huoshanense and has high medicinal value. A high dose of D‐galactose (D‐gal) is commonly utilized in the aging model establishment. In this study, we explored whether DHP shields PC12 cells and aging mice from D‐gal caused damage and the possible mechanism. In vitro experiments, D‐gal induced PC12 cells were used to investigate, and then DHP was used for treatment. In vivo experiments, 72 SPF ICR male mice were randomly divided into six groups (control: normal saline; model: D‐gal (400 mg/kg); VE group: VE (50 μg/ml); DHP groups: D‐gal + DHP (15.6 mg/ml; 31.2 mg/ml; 62.4 mg/ml)). The results showed that DHP could enhance the viability of D‐gal injured PC12 cells and prevent cell apoptosis. DHP effectively promoted the transition from phase G0/G1 to phase S and inhibited cell cycle arrest. DHP has a potential neuroprotective effect on D‐gal caused cognitive and memory disorders in mice. On the one hand, DHP protects the antioxidant enzymes SOD, GSH‐PX, and CAT from excessive ROS buildup. On the other hand, DHP was demonstrated to block the expression of the P53/P21 signaling pathway‐related proteins P53, P21, and P16. These results imply that DHP could be a potential neuroprotective agent against aging. Practical applications Cognitive and memory decline caused by aging problems has become a problem in recent years. There are many theories about aging, among which oxidative stress is considered to be one of the important pathophysiological parts of various diseases in the aging process. In this study, DHP could not only improve the damage of D‐Gal to PC12 cells, but also improve the cognitive and memory impairment caused by D‐Gal in mice. In conclusion, this study verified the anti‐aging effect of DHP from in vitro and in vivo experiments, and its mechanism may involve the P53/P21 pathway. Therefore, this study indicated that polysaccharides from Dendrobium huoshanense, a traditional Chinese medicine of homologous medicine and food, had potential and industrial value as potential anti‐aging drugs.