Fmr1 protects cardiomyocytes against lipopolysaccharide-induced myocardial injury
Authors: Chen Ye
Jiasheng Bao
Zhengwen Zhou
Zhelan Zheng
Journal: Experimental and therapeutic medicine (2018)
Discipline: CLINICAL MEDICINE
Keywords: apoptosis; cardiomyocyte; fragile X mental retardation 1; lipopolysaccharide; myocardial injury
Affiliations: Department of Electrocardiogram Diagnosis, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China, Department of Cardiovascular Medicine, Zhejiang Hospital, Hangzhou, Zhejiang 310013, P.R. China, Department of Cardiovascular Ultrasonic Center, The First Affiliated Hospital of Zhejiang University, The First Hospital of Zhejiang Province, Hangzhou, Zhejiang 310003, P.R. China

Abstract:  The present study explored the mechanisms by which fragile X mental retardation 1 (fmr1) overexpression inhibits lipopolysaccharide (LPS)-induced cardiomyocyte injury. Factors including oxidative stress reaction, mitochondrial membrane potential variation and cell apoptosis were evaluated. The viability of H9c2 cells was evaluated with a Cell Counting Kit-8 assay after cells were treated with LPS at different concentrations (0, 1, 3, 6 and 9 µg/ml) for various durations (4, 12 and 24 h). Flow cytometry was used to determine variations in reactive oxygen species (ROS), mitochondrial membrane potential and cell apoptosis. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to detect the levels of apoptosis-associated factors, and western blot analysis was used to determine the phosphorylation levels of phosphoinositide-3 kinase (PI3K), Akt and forkhead box (Fox)O3a. The results indicated that LPS decreased the viability of H9c2 cells in a dose- and time-dependent manner. Overexpression of fmr1 inhibited the LPS-induced decrease in the mitochondrial membrane potential and the production of ROS as well as apoptosis in H9c2 cells. Fmr1 also inhibited LPS-induced reductions in antioxidant enzyme activities, including those of superoxide dismutase and reduced/oxidized glutathione ratio, and decreased LPS-associated increases in the lipid peroxidation product malondialdehyde. Apoptosis-associated factors were identified to be involved in the effects of Fmr1. Overexpression of Fmr1 attenuated LPS-associated increases in the apoptosis-activating factors B-cell lymphoma 2 (Bcl-2)-associated X protein and caspase-3 and decreases in apoptosis inhibitors, including Bcl-2 and X-linked inhibitor of apoptosis protein. Fmr1 overexpression also reduced LPS-induced increases in the phosphorylation levels of PI3K, Akt and FoxO3a. In conclusion, fmr1 overexpression alleviated oxidative stress and apoptosis in H9c2 cardiomyocytes injured by LPS via regulating oxidative stress and apoptosis-associated factors, as well as the PI3K/Akt pathway. This information may provide a novel and effective therapeutic strategy for heart diseases. 

Retracted: No

PubPeer comments:
 In figure 3, at least one of the flow cytometry plots seems to be a re-sampling re-gating of the same population. I have highlighted some identical regions in the plot, however there are plenty more. In most counts seem to have been  added in in the upper quadrants of the rightmost plot and in the lower quadrants of the leftmost plot. ![file] I am not sure how this could have happened, but I suggest the authors revisit their raw data. ,