Myocardin reverses insulin resistance and ameliorates cardiomyopathy by increasing IRS-1 expression in a murine model of lipodystrophy caused by adipose deficiency of vacuolar H+-ATPase V0d1 subunit.

Aim: Adipose tissue (AT) dysfunction that occurs in both obesity and lipodystrophy is associated with the development of cardiomyopathy. However, it is unclear how dysfunctional AT induces cardiomyopathy due to limited animal models available. We have identified vacuolar H+-ATPase subunit Vod1, encoded by Atp6v0d1, as a master regulator of adipogenesis, and adipose-specific deletion of Atp6v0d1 (Atp6v0d1AKO) in mice caused generalized lipodystrophy and spontaneous cardiomyopathy. Using this unique animal model, we explore the mechanism(s) underlying lipodystrophy-related cardiomyopathy. Methods and Results: Atp6v0d1AKO mice developed cardiac hypertrophy at 12 weeks, and progressed to heart failure at 28 weeks. The Atp6v0d1AKO mouse hearts exhibited excessive lipid accumulation and altered lipid and glucose metabolism, which are typical for obesity- and diabetes-related cardiomyopathy. The Atp6v0d1AKO mice developed cardiac insulin resistance evidenced by decreased IRS-1/2 expression in hearts. Meanwhile, the expression of forkhead box O1 (FoxO1), a transcription factor which plays critical roles in regulating cardiac lipid and glucose metabolism, was increased. RNA-seq data and molecular biological assays demonstrated reduced expression of myocardin, a transcription coactivator, in Atp6v0d1AKO mouse hearts. RNA interference (RNAi), luciferase reporter and ChIP-qPCR assays revealed the critical role of myocardin in regulating IRS-1 transcription through the CArG-like element in IRS-1 promoter. Reducing IRS-1 expression with RNAi increased FoxO1 expression, while increasing IRS-1 expression reversed myocardin downregulation-induced FoxO1 upregulation in cardiomyocytes. In vivo, restoring myocardin expression specifically in Atp6v0d1AKO cardiomyocytes increased IRS-1, but decreased FoxO1 expression. As a result, the abnormal expressions of metabolic genes in Atp6v0d1AKO hearts were reversed, and cardiac dysfunctions were ameliorated. Myocardin expression was also reduced in high fat diet-induced diabetic cardiomyopathy and palmitic acid-treated cardiomyocytes. Moreover, increasing systemic insulin resistance with rosiglitazone restored cardiac myocardin expression and improved cardiac functions in Atp6v0d1AKO mice. Conclusion: Atp6v0d1AKO mice are a novel animal model for studying lipodystrophy- or metabolic dysfunction-related cardiomyopathy. Moreover, myocardin serves as a key regulator of cardiac insulin sensitivity and metabolic homeostasis, highlighting myocardin as a potential therapeutic target for treating lipodystrophy- and diabetes-related cardiomyopathy.

Effect of experiential health education on diet control of college students with type 2 pre diabetes mellitus / 中国学校卫生

Objective@#To understand the influence of experiential health education on diet control of college students with pre diabetes mellitus, and to provide reference for healthy eating habits promotion among college students.@*Methods@#According to the method of random number table, 78 pre diabetic college students screened from Changzhi Medical College from September 2020 to June 2021 were randomly assigned to observation group and control group (39 students in each group). The control group received routine health education for 10 months, once a week for 1 hour each time; On the basis of the above, the observation group received experiential health education once a week for 1 hour, including diet experience, exercise experience, blood sugar test experience and chronic complications experience. Blood glucose and lipids level, body mass index (BMI), dietary control as well as the stages of change for dietary control behavior were compared between the two groups.@*Results@#There was significant difference between the observation group and the control group in the stages of change for dietary control behavior 10 months after intervention ( χ 2=8.92, P <0.05). The compliance score of the observation group was significantly higher than that of the control group in the same period 10 months after the intervention ( t =3.74, P <0.01), the score of the knowledge of diet control in the observation group 10 months after intervention was significantly higher than that in the control group ( t =11.51, P <0.05). The levels of BMI, TG and TC in the observation group were significantly lower than those in the control group at 5 and 10 months after intervention, and the differences were statistically significant ( P <0.05).@*Conclusion@#Experiential health education helps to promote awareness of diabete related knowledge, enhance self management behavior and good diet control habits, and is effective for blood glucose control.