Effect of calcitonin gene-related peptide on autophagy in hypoxic/reoxygenated cardiomyocytes through regulation of PI3K/Akt/mTOR signaling pathway.
10.3760/cma.j.cn121430-20231109-00960
- Author:
Libo DONG
1
;
Dajiang YUAN
2
Author Information
1. Department of Anesthesiology, Shanxi Medical University, Taiyuan 030000, Shanxi, China.
2. Department of Critical Care Medicine, Second Hospital of Shanxi Medical University, Taiyuan 030000, Shanxi, China. Corresponding author: Yuan Dajiang, Email: yuandajiang@sina.com.
- Publication Type:Journal Article
- MeSH:
Animals;
Myocytes, Cardiac/drug effects*;
Signal Transduction/drug effects*;
Rats;
TOR Serine-Threonine Kinases/metabolism*;
Calcitonin Gene-Related Peptide/pharmacology*;
Proto-Oncogene Proteins c-akt/metabolism*;
Autophagy/drug effects*;
Cell Line;
Cell Hypoxia;
Phosphatidylinositol 3-Kinases/metabolism*
- From:
Chinese Critical Care Medicine
2025;37(1):53-58
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To investigate the effects of calcitonin gene-related peptide (CGRP) on autophagy in hypoxic/reoxygenated (H/R) cardiomyocytes and its relationship with the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway.
METHODS:The rat cardiomyocyte cell line H9c2 was routinely cultured in vitro and passaged for experiments when the cells grew to 80% fusion. (1) CGRP dosage screening experiment: the cells were divided into blank control group, H/R group and different dosages of CGRP pretreatment groups. H9c2 cells were placed in a closed hypoxia chamber for 2 hours and then reoxygenated in a conventional incubator for 12 hours to prepare the H/R model. The CGRP pretreatment groups were pretreated with 0.01, 0.1, 0.5, 1, 5, and 10 μmol/L CGRP before the modeling process. The blank control group was not given any treatment. Cell counting kit-8 (CCK-8) was used to detect the cell survival rate, and the most suitable drug dosage was screened out. (2) Intervention experiment: H9c2 cells were divided into blank control group, H/R group, CGRP+H/R group, and CGRP+PI3K target inhibitor ly294002 (LY)+H/R group. H/R group was prepared as cellular H/R model. CGRP (1 μmol/L) alone or in combination with LY (10 μmol/L) was administered to CGRP+H/R group and CGRP+LY+H/R group, respectively, prior to the preparation of cellular H/R model. The blank control group was cultured routinely without treatment. The cell survival rate was detected by CCK-8. The level of lactate dehydrogenase (LDH) release was detected by colorimetric assay. The expressions of autophagy-related proteins [autophagy effector protein Beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II), autophagy protein p62] and PI3K/Akt/mTOR signaling pathway proteins [phosphorylated Akt (p-Akt), phosphorylated mTOR (p-mTOR)] were detected by Western blotting.
RESULTS:(1) Results of CGRP dosage screening experiment: compared with the blank control group, the cell survival rate of the H/R group decreased significantly; and after giving 0.1, 0.5, 1, 5 μmol/L CGRP for pretreatment, the cell survival rate increased significantly, and intervention effect of 1 μmol/L CGRP was the best, and the difference was statistically significant when compared with that of the H/R group [(74.23±6.18)% vs. (23.43±4.09)%, P < 0.01], so it was used as the intervention dosage for the subsequent experiment. (2) Intervention experiment results: compared with the blank control group, the cell survival rate in the H/R group was significantly reduced, the level of LDH release was significantly increased, the protein expressions of Beclin-1 and LC3-II were significantly increased, and the protein expressions of p62, p-Akt and p-mTOR were significantly reduced, indicating that the death of cardiomyocytes occurred after the treatment of H/R and was accompanied by the elevation of autophagy level, and this process was associated with the activation of PI3K/Akt/mTOR signaling pathway. Compared with the H/R group, CGRP pretreatment increased cell survival rate [(76.02±2.43)% vs. (46.15±3.29)%, P < 0.01], decreased the level of LDH release (U/L: 169.83±11.65 vs. 590.17±34.50, P < 0.01), and down-regulated the protein expressions of Beclin-1 and LC3-II [Beclin-1 protein (Beclin-1/β-actin): 1.27±0.15 vs. 1.93±0.19, LC3-II protein (LC3-II/LC3-I): 1.27±0.13 vs. 1.98±0.18, both P < 0.01], up-regulated the protein expressions of p62, p-Akt, p-mTOR [p62 protein (p62/β-actin): 0.96±0.02 vs. 0.63±0.05, p-Akt protein (p-Akt/Akt): 0.76±0.04 vs. 0.48±0.02, p-mTOR protein (p-mTOR/mTOR): 1.13±0.09 vs. 0.68±0.15, all P < 0.05], suggesting that CGRP was able to reduce the H/R-induced cardiomyocyte injury, and this process was accompanied by a decrease in the level of cellular autophagy and activation of the PI3K/Akt/mTOR signaling pathway. Compared with the CGRP+H/R group, the cell survival rate was significantly lower than that in the CGRP+LY+H/R group [(56.95±6.63)% vs. (76.02±2.43)%, P < 0.01], LDH release level was significantly higher (U/L: 436.00±27.44 vs. 169.83±11.65, P < 0.01), and the protein expressions of Beclin-1 and LC3-II were significantly up-regulated [Beclin-1 protein (Beclin-1/β-actin): 1.63±0.12 vs. 1.27±0.15, LC3-II protein (LC3-II/LC3-I): 1.61±0.13 vs. 1.27±0.13, both P < 0.01], and significantly down-regulated p62, p-Akt, and p-mTOR protein expressions [p62 protein (p62/β-actin): 0.57±0.09 vs. 0.96±0.02, p-Akt protein (p-Akt/Akt): 0.45±0.01 vs. 0.76±0.04, p-mTOR protein (p-mTOR/mTOR): 0.66±0.06 vs. 1.13±0.09, all P < 0.05], suggesting that PI3K-targeted inhibitor was able to reverse the protective effect of CGRP on H/R cells.
CONCLUSIONS:CGRP pretreatment attenuated H/R-induced cardiomyocyte injury, increased cell survival rate, and reduced cellular LDH release. This effect may be achieved through inhibiting the activation of PI3K/Akt/mTOR signaling pathway.
