Objective:To explore the impact of the stimulator of interferon genes(STING)-interferon regulatory factor 3(IRF3)pathway on the senescence of rapid pacing HL-1 myocytes.Methods:HL-1 cells were divided into five groups: the control group(HL-1 cells without any treatment), pacing group(HL-1 cells paced for 48 hours), STING siRNA group(HL-1 cells paced for 48 hours and transfected with STING siRNA), NC siRNA group(HL-1 cells paced for 48 hours and transfected with NC siRNA), and H151 inhibitor group(HL-1 cells paced for 48 hours with the addition of 1 μmol/L STING inhibitor H151). Mitochondrial membrane potential was assessed in control and pacing group cells, and mitochondrial MitoTracker and TFAM co-localization staining was performed on these cells.Cellular senescence was evaluated using β-galactosidase staining in each group, and the positive rate of cellular senescence was observed and calculated.Western blotting was employed to detect the expression levels of STING, IRF3, P-IRF3, P16, P21, and P53 proteins in all groups.Immunofluorescence was utilized to examine the expression distribution of STING and P21 across the various groups.ELISA was performed to measure the concentrations of interleukin(IL)-1β, IL-6, and IL-8 in the cell supernatants from each group as part of the senescence-associated secretory phenotype(SASP).Results:Compared with the control group, the ratio of mitochondrial JC-1 multimer to monomer was significantly decreased in the pacing group( t=16.42, P<0.05), the co-localization of mitochondrial MitoTracker and TFAM in the cells was significantly weakened, the proportion of cells with positive cellular senescence-associated β-galactosidase staining significantly increased in the pacing group, the expression levels of STING, P-IRF3/IRF3, P16, P21, and P53 proteins were significantly elevated in the pacing group, and the concentrations of IL-1β, IL-6, and IL-8 in the cell supernatants were markedly increased.Compared with the pacing group, the proportion of cells with positive cellular senescence-associated β-galactosidase staining decreased in the STING siRNA group and H151 inhibitor group ( F= 18.13, P<0.05), the expression levels of STING, P-IRF3/IRF3, P16, P21, and P53 were reduced in the STING siRNA group and H151 inhibitor group ( F=16.84, 26.56, 74.70, 31.80, 31.23, all P<0.05), and the concentrations of IL-1β, IL-6, and IL-8 in the cell supernatants decreased( F=197.80、1 339.00、1 308.00, all P<0.001). Conclusions:Rapid pacing of HL-1 cells can promote mtDNA release into the cytoplasm, activate the STING-IRF3 pathway, accelerate cellular senescence, and enhance the secretion of SASP.Inhibiting the expression of STING can delay the senescence induced by the rapid pacing of HL-1 cells and reduce SASP secretion.

Objective:To explore the impact of the stimulator of interferon genes(STING)-interferon regulatory factor 3(IRF3)pathway on the senescence of rapid pacing HL-1 myocytes.Methods:HL-1 cells were divided into five groups: the control group(HL-1 cells without any treatment), pacing group(HL-1 cells paced for 48 hours), STING siRNA group(HL-1 cells paced for 48 hours and transfected with STING siRNA), NC siRNA group(HL-1 cells paced for 48 hours and transfected with NC siRNA), and H151 inhibitor group(HL-1 cells paced for 48 hours with the addition of 1 μmol/L STING inhibitor H151). Mitochondrial membrane potential was assessed in control and pacing group cells, and mitochondrial MitoTracker and TFAM co-localization staining was performed on these cells.Cellular senescence was evaluated using β-galactosidase staining in each group, and the positive rate of cellular senescence was observed and calculated.Western blotting was employed to detect the expression levels of STING, IRF3, P-IRF3, P16, P21, and P53 proteins in all groups.Immunofluorescence was utilized to examine the expression distribution of STING and P21 across the various groups.ELISA was performed to measure the concentrations of interleukin(IL)-1β, IL-6, and IL-8 in the cell supernatants from each group as part of the senescence-associated secretory phenotype(SASP).Results:Compared with the control group, the ratio of mitochondrial JC-1 multimer to monomer was significantly decreased in the pacing group( t=16.42, P<0.05), the co-localization of mitochondrial MitoTracker and TFAM in the cells was significantly weakened, the proportion of cells with positive cellular senescence-associated β-galactosidase staining significantly increased in the pacing group, the expression levels of STING, P-IRF3/IRF3, P16, P21, and P53 proteins were significantly elevated in the pacing group, and the concentrations of IL-1β, IL-6, and IL-8 in the cell supernatants were markedly increased.Compared with the pacing group, the proportion of cells with positive cellular senescence-associated β-galactosidase staining decreased in the STING siRNA group and H151 inhibitor group ( F= 18.13, P<0.05), the expression levels of STING, P-IRF3/IRF3, P16, P21, and P53 were reduced in the STING siRNA group and H151 inhibitor group ( F=16.84, 26.56, 74.70, 31.80, 31.23, all P<0.05), and the concentrations of IL-1β, IL-6, and IL-8 in the cell supernatants decreased( F=197.80、1 339.00、1 308.00, all P<0.001). Conclusions:Rapid pacing of HL-1 cells can promote mtDNA release into the cytoplasm, activate the STING-IRF3 pathway, accelerate cellular senescence, and enhance the secretion of SASP.Inhibiting the expression of STING can delay the senescence induced by the rapid pacing of HL-1 cells and reduce SASP secretion.

Objective To investigate the regulatory effects of bombesin on the growth of human immortalized gastric epithelial cell line(GES-1), and its mechanisms. Methods ① The expression of gastrin releasing peptide receptor(GRP-R) mRNA in GES-1 was detected. ② The expression of GRP-R protein was tested by cross-linking experiment and the location of the receptors in the cells were investigated by cytochemistry. ③GES-1 cell line was incubated with varying concentrations of bombesin with or without its antagonist and growth of the cell line was determined. ④The effect of protein kinase C (PKC) inhibitor on cell growth induced by bombesin was studied. ⑤After treated with bombesin, the intracellular IP 3 and translocation of PKC activity were measured in GES-1. ⑥Semiquantification of GRP-R mRNA in this cell line treated with bombesin was performed. Results ①Expression of mRNA of GRP-R was demonstrated in GES-1 cells. ②The GRP-R protein was about 75?103 as revealed by cross-linking study, and the receptors were identified on the cell membranes by cytochemistry. ③Bombesin stimulated the growth of GES-1 significantly, which could be inhibited by specific antagonist of bombesin. ④Bombesin-induced growth of GES-1 was also inhibited by PKC inhibitor. ⑤Bombesin induced an increase of IP 3 generation in GES-1 as well as remarkable translocation of PKC activity from cytoplasm to the cell membranes. ⑥An increase in GRP-R mRNA was induced by treatment of cell line with bombesin. Conclusions Bombesin stimulates the growth of this GES-1 via its receptor GRP-R and through IP 3, PKC signal pathway. The increase in expression of GRP-R mRNA in GES-1 induced by bombesin indicates that bombesin might upregulate the GRP-R in the GES-1 cells.