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Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective·To investigate the effects of several key proteins of severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) on macropinocytosis in various cell models. Methods· The interactions between spike protein receptor-binding domain (S-RBD), nucleocapsid protein (N) and non-structural protein-7 (NSP7) of SARS-COV-2 and HEK-293T intracellular proteins were explored by co-immunoprecipitation assay. In vitro, S-RBD, N and NSP7 proteins of SARS-CoV-2 were incubated with HEK-293T/bEnd. 3/Beas-2b cells (normal cell models), respectively, and the changes of macropinocytosis level of cells labeled with fluorescein isothiocyanate (FITC) -70 kDa-dextran were observed. In vitro, S-RBD, N and NSP7 proteins of SARS-CoV-2 were incubated with inflammatory cells induced by lipopolysaccharide (LPS), respectively, and the changes of macropinocytosis level of inflammatory cells were analyzed. In the normal cell models and inflammatory cell model, EIPA or lipoprotein nano-drug carriers loaded with Rab5 small interfering RNA (siRNA) were used to inhibit the macropinocytosis induced by SARS-CoV-2 proteins, respectively, and the uptake of S-RBD, N and NSP7 proteins by cells were further observed. Results· The three proteins of SARSCOV- 2 could bind to Rab small GTPase proteins after being absorbed into cells. It was found that S-RBD, N and NSP7 proteins of SARS-COV-2 could induce the macropinocytosis after entering the HEK-293T/bEnd. 3/Beas-2b cells. Furthermore, the three proteins of SARS-COV-2 could enhance the megapinocytosis of the inflammatory cell. After treatment with EIPA (75 μmol/L) or lipoprotein nano-drug carriers loaded with Rab5 siRNA, the uptake of S-RBD, N and NSP7 proteins were decreased in both types of cells. Conclusion·S-RBD, N and NSP7 proteins of SARS-CoV-2 can up-regulate megapinocytosis levels in various cell models, especially in the case of combined inflammation infection. At the same time, macropinocytosis inhibitor / lipoprotein nano-drug carrier can inhibit the macropinocytosis up-regulated by the above proteins, and then reduce the entry levels of viral proteins. [Key words] macropinocytosis; severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); EIPA; Rab5 [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Veterinary Science / Zhongguo Shouyi Xuebao is the property of Chinese Society of Veterinary Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To investigate the effects of continuing exercise and load-bearing interval exercise on skeletal muscle tissue cell morphology, Ras-related proteins 5 (Rab5) mRNA and protein expression and glucose metabolism in skeletal muscle of type 2 diabetic mellitus (T2DM) rats. Methods: Eight SD rats were selected as controls group (CR), the others SD rats were fed with high fat and high sugar diet for 6 weeks before injecting STZ (35 mg/kg) to construct the T2DM model. Twenty-four T2DM rats were randomly devided into T2DM model group (DRM), continuing exercise group (DCRE) and load-bearing interval exercise group (DWRE), 8 rats in each group. DCRE exercise protocol, that was 15 m/min (10 min), 20 m/min (40 min), 15 m/min (10 min), during the first 1～2 weeks, and 18 m/min (10 min), 25 m/min (40 min), 15 m/min (10 min), during the second 3～8 weeks. DWRE exercise protocol: load weight 15% / 1～2 weeks, 30% / 3～4 weeks, 45% / 5～8 weeks, with 15 m/min (5 min), 12 groups and 3 min rest between groups. After 8 weeks, pathological and morphological changes of skeletal muscle were observed by HE. Rab5 and Glucose transporte 4 (GLUT4) mRNA expressions of skeletal muscle were tested by qRT-PCR. Rab5 protein expression in skeletal muscle was tested by immunofluorescence histochemistry and Western blot, and plasma Rab5 and Glycosylated Hemoglobin (GHb) concentrations were detected by ELISA. Results: Comparison with CR, DRM showed pathological damage of skeletal muscle, the expressions of Rab5 mRNA, protein and GLUT4 mRNA were all decreased in skeletal muscle ( P ＜0.01), the serum levels of Rab5 and GHb were both significantly elevated ( P ＜0.01). Comparison with DRM, both DCRE and DWRE significantly improved pathological damages of skeletal muscle, the expressions of Rab5 mRNA, protein and GLUT4 mRNA were all increased in skeletal muscle ( P ＜ 0.05, P ＜0.01), the serum levels of Rab5 and GHb were decreased ( P ＜0.05, P ＜0.01), and there was no statistical difference between DCRE and DWRE groups ( P ＞0.05). Conclusion: Two exercise modes can improve the pathological injury of skeletal muscle in type 2 diabetic rats, and enhance GLUT4 transport capacity by improving the expression of Rab5 gene and protein in skeletal muscle, and alleviate the imbalance of glucose metabolism homeostasis in skeletal muscle. However, there was no significant difference between the effects of two exercise modes on Rab5 protein and glucose metabolism in skeletal muscle.