RESUMO
AIM: Post-transcriptional modifications and their specific mechanisms are the focus of research on the regulation of myocardial damage. Stress granules (SGs) can inhibit the inflammatory response by inhibiting the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway. This study investigated whether alkylation repair homologue protein 5 (ALKBH5) could affect myocardial inflammation and apoptosis during diabetic myocardial ischaemia-reperfusion injury (IRI) through the cGAS-STING pathway via SGs. METHODS: A diabetes ischaemia-reperfusion rat model and a high glucose hypoxia/reoxygenation cell model were established. Adeno-associated virus (AAV) and lentivirus (LV) were used to overexpress ALKBH5, while the SG agonist arsenite (Ars) and the SG inhibitor anisomycin were used as interventions. Then, the levels of apoptosis and related indicators in the cell and rat models were measured. RESULTS: In the in vivo experiment, compared with the normal sham group, the degree of myocardial tissue damage, creatine kinase-MB and cardiac troponin I in serum, and myocardial apoptosis, the infarcted area of myocardium, and the level of B-cell lymphoma 2 associated X protein, cGAS-STING pathway and inflammatory factors in the diabetes ischaemia-reperfusion group were significantly increased. However, the expression of SGs and the levels of ALKBH5, rat sarcoma-GTPase-activating protein-binding protein 1, T-cell intracellular antigen-1 and Bcl2 were significantly decreased. After AAV-ALKBH5 intervention, the degree of myocardial tissue damage, degree of myocardial apoptosis, and extent of myocardial infarction in myocardial tissue were significantly decreased. In the in vitro experiment, compared with those in the normal control group, the levels of lactate dehydrogenase, inflammation and apoptosis were significantly greater, and cell viability and the levels of ALKBH5 and SGs were decreased in the high glucose and hypoxia/reoxygenation groups. In the high glucose hypoxia/reoxygenation cell model, the degree of cell damage, inflammation, and apoptosis was greater than those in the high glucose and hypoxia/reoxygenation models, and the levels of ALKBH5 and SGs were further decreased. LV-ALKBH5 and Ars alleviated the degree of cell damage and inhibited inflammation and cell apoptosis. The inhibition of SGs could partly reverse the protective effect of LV-ALKBH5. The cGAS agonist G140 antagonized the inhibitory effects of the SG agonist Ars on cardiomyocyte apoptosis, inflammation and the cGAS-STING pathway. CONCLUSION: Both ALKBH5 and SGs inhibited myocardial inflammation and apoptosis during diabetic myocardial ischaemia-reperfusion. Mechanistically, ALKBH5 might inhibit the apoptosis of cardiomyocytes by promoting the expression of SGs through the cGAS-STING pathway.
RESUMO
To study the mechanism and action of Cinnamomi Ramulus in ameliorating intrahepatic cholestasis induced by α-isothiocyanate( ANIT) in rats by regulating FXR pathway. Forty SD rats were randomly divided into normal group,model group,positive control( ursodeoxycholic acid) group( 60 mg·kg~(-1)),Cinnamomi Ramulus treatment( 60 mg·kg~(-1)·d~(-1)) group,and Cinnamomi Ramulus treatment( 20 mg·kg~(-1)·d~(-1)) group,with 8 rats in each group. Except for the normal control group,the other groups were intragastrically administered with the corresponding concentrations of continuous aqueous solution( 0. 005 m L·g~(-1)),once a day,for 7 days.Except for the normal group,the other groups were treated with ANIT( 100 mg·kg~(-1)),once a day,for 3 days. Blood was taken from the abdominal aorta 24 hours after the last administration,and serum alanine aminotransferase( ALT),aspartate aminotransferase( AST),total bilirubin( TBi L),and total bile acid( TBA) were measured. 1. 5-2 cm of rat liver tissue was taken. After fixation with10% formaldehyde,paraffin-embedded sections were taken,HE staining was performed,and immunohistochemistry( IHC) was used to analyze the expression of FXR. RNA and protein were extracted from rat liver tissue to detect FXR mRNA expression,as well as bile acid synthesis and detoxification,transport related SHP,UGT2 B4,BSEP protein expressions at downstream of FXR. Compared with the normal group,serum ALT,AST,TBi L,and TBA levels were elevated in the model group( P<0. 01),liver damage was severe,FXR protein's optical density decreased,FXR mRNA expression decreased,and SHP,UGT2 B4,BSEP protein expressions were decreased( P<0. 05,P<0. 01). Compared with the model group,the drug group could reduce serum ALT,AST,TB,TBA levels to different degrees( P<0. 05,P<0. 01),alleviate liver tissue damage,increase the optical density of FXR protein,and promote the expressions of FXR mRNA and FXR,SHP,BSEP and UGT2 B4 proteins( P<0. 05,P<0. 01). Cinnamomi Ramulus can alleviate ANIT-induced intrahepatic cholestasis,and reduce hepatocyte injury and serum ALT,AST,TBi L and TBA levels. The mechanism may be through FXR-SHP,FXR-UGT2 B4,FXR-BSEP signaling pathways. Therefore,in the pathogenesis of intrahepatic cholestasis,we can try to further explore in alleviating intrahepatic cholestasis with Cinnamomi Ramulus,so as to provide effective drugs for clinical treatment of intrahepatic cholestasis.