Renoprotective effect of berberine via regulating the PGE2 -EP1-Gαq-Ca(2+) signalling pathway in glomerular mesangial cells of diabetic rats.
G-protein coupled receptor-mediated pathogenesis is of great importance in the development of diabetic complications, but the detailed mechanisms have not yet been clarified. Therefore, we aimed to explore the roles of the prostaglandin E2 receptor 1 (EP1)-mediated signalling pathway and develop a corresponding treatment for diabetic nephropathy (DN). To create the DN model, rats fed a high-fat and high-glucose diet were injected with a single dose of streptozotocin (35 mg/kg, i.p.). Then, rats were either treated or not with berberine (100 mg/kg per day, i.g., 8 weeks). Cells were isolated from the renal cortex and cultured in high-sugar medium with 20% foetal bovine serum. Prostaglandin E2 (PGE2 ) levels were determined by ELISA, and cells were identified by fluorescence immunoassay. We measured the biochemical characteristics and observed morphological changes by periodic-acid-Schiff staining. The expression of the EP1 receptor and the roles of GRK2 and β-arrestin2 were identified using western blotting and flow cytometry. Downstream proteins were detected by western blot, while molecular changes were assessed by ELISA and laser confocal scanning microscopy. Berberine not only improved the majority of biochemical and renal functional parameters but also improved the histopathological alterations. A significant increase in PGE2 level, EP1 membrane expression and Gαq expression, and concentration of Ca(2+) were observed, accompanied by increased GRK2 and β-arrestin2 levels soon afterwards. Berberine decreased the abnormal concentration of Ca(2+) , the increased levels of PGE2 , the high expression of EP1 and Gαq and suppressed the proliferation of mesangial cells. The EP1 receptor, a critical therapeutic target of the signalling pathway, contributed to mesangial cell abnormalities, which are linked to renal injury in DN. The observed renoprotective effects of berberine via regulating the PGE2 -EP1-Gαq-Ca(2+) signalling pathway indicating that berberine could be a promising anti-DN medicine in the future.
Affiliated Anhui Provincial Hospital, Anhui Medical University, Anhui Province, China.
Wei-Jian
WJ
Ni
Affiliated Anhui Provincial Hospital, Anhui Medical University, Anhui Province, China.
Li-Qin
LQ
Tang
West Branch of Anhui Provincial Hospital, Anhui Provincial Cancer Hospital, Anhui Province, China.
Hong
H
Zhou
Affiliated Anhui Provincial Hospital, Anhui Medical University, Anhui Province, China.
Hai-Hua
HH
Ding
Affiliated Anhui Provincial Hospital, Anhui Medical University, Anhui Province, China.
Yuan-Ye
YY
Qiu
D000818:Animals; D001599:Berberine / Q000494:pharmacology / Q000627:therapeutic use*; D015415:Biomarkers / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000473:pathology; D015232:Dinoprostone / Q000378:metabolism*; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000378:metabolism; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism*; D007677:Kidney Function Tests; D007678:Kidney Glomerulus / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism*; D020011:Protective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017207:Rats, Sprague-Dawley; D058306:Receptors, Prostaglandin E, EP1 Subtype / Q000378:metabolism*; D000071557:beta-Arrestins / Q000378:metabolism
D015415:Biomarkers; D020011:Protective Agents; D058306:Receptors, Prostaglandin E, EP1 Subtype; D000071557:beta-Arrestins; D001599:Berberine; C496569:Grk2 protein, rat; D054769:G-Protein-Coupled Receptor Kinase 2; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D015232:Dinoprostone; D002118:Calcium
EP1 receptor; berberine; diabetic nephropathy; glomerular mesangial cell; signalling pathway