Effects Of Trimethylglycine On High-fat Induced Lipod Deposition In AMPKα1Knockout Mice

Abnormal fat deposition caused by excess energy would lower meat quality in animal husbandry and cause obesity and other metabolic deseases. Trimethylglycine is a naturally compound, which has been used as feed additive to modify the carcass composition and also to alleviate ectopic fat accumulation induced by high-fat diet. However, the related mechanism remains elusive. Consequently, the present study was conducted to determine whether trimethylglycine could rectify impaired fatty acid oxidation and N6-methyladenosine (m6A) mRNA methylation status, and how AMP-activated protein kinase α1 subunit (AMPKal) was involved. Moreover, we explored that whether AMPK activation would affect m6A methylation and whether methylation inhibitor would affect the effects of trimethylglycine on fatty acid oxidation in primary adipocytes seperated from high-fat feeding mice. We are aimed to further elucidate the mechanism how trimethylglycine decrease fat deposition. Results are as below:Exp.1 Effects of trimethylglycine on weight gain and serum parameters on high-fat-induced wild type and AMPKal KO miceWild type and AMPKal KO mice fed with high-fat diet were used to study the effects of trimethylglycine on weight gain, serum TG and hormone concentration. The results showed that trimethylglycine significantly decreased high-fat induced weight gain, serum TG and FFA level, as well as serum insulin and leptin level (P＜0.05). However, no such effects of trimethylglycine was obseved in the AMPKal KO mice. These results indicated that AMPKal was involved in the effects of trimethylglycine on weight gain, serum TG and hormone concentration.Exp.2 Effects of trimethylglycine on fat deposition in high-fat-induced wild type and AMPK α1 KO miceAMPKal KO mice were used to study the effects of trimethylglycine on high-fat-induced fat deposition and m6A methylation in liver and adipose tissue. The results showed that trimethylglycine significantly decreased fat deposition in liver and adipose tissue of high-fat-induced wild type (WT) mice (P<0.05). And trimethylglycine also improved fatty acid oxidation, mitochondrial function as well as m6A methylation status (P<0.05). However, in the AMPKal KO mice, these aforementioned effects were abolished in adipose tissue. And although trimethylglycine improved hepatic fatty acid oxidation and mitochondrial function, it did not alleviate ectopic lipid accumation in liver induced by high-fat diet. These results suggested that AMPKal is required for anti-adipogenic effects of trimethylglycine.Exp.2 Trimethylglycine decrease fat depostion in primary adipocytes through AMPKalPrimary adipocytes seperated from epididymal fat of high-fat-induced mice were used to study how AMPKal was involved in the effects of trimethylglycine on fat deposition. And furthermore, whether activation of AMPK would affect m6A methylation and whether methylation inhibitor would affect the effects of trimethylglycine on fat deposition were explored. The results showed that trimethylglycine increased fatty acid oxidation and mitochondrial function, and increased m6A methylation level in primary adipocytes (P<0.05). However, after knockdown AMPK α1, no significant effects of trimethylglycine on fatty acid oxidation and mitochondrial function were observed in primary adipocytes; Activation of AMPK significantly increased the level of m6A methylation and decreased FTO protein expression (P<0.05); In addition, when methylation were inhibited, trimethylglycine had no significant effects on fatty acid oxidation and mitochondrial function in primary adipocytes. These results indicated that trimethylglycine may increase lipid oxidation through activation of AMPKal and improving m6A methylation.In conclusion, trimethylglycine alleviated high-fat-induced lipid accumution through increasing fatty acid oxidation and improving mitochondrial function, and AMPKal may be the key factor invovled in the effects of trimethylglycine on fat deposition and m6A methylation.