Differential expression of AMPK subunit isoforms in subcutaneous adipose tissue of post-mortem subjects with BMI>25kg/m2

Abstract

AMP-activated protein kinase (AMPK) is a heterotrimeric complex that is made up of α-, β- and γ- subunits isoforms making up various isomers. AMPK has been shown to improve catabolic ATP-generating pathways, making it a promising therapeutic target. Studies have shown that different AMPK isomers are predominant in different tissues. However, determination of the predominant isomer in adipose tissue remains obscure. The goal of this study is to identify the AMPK isomers present in human subcutaneous adipose tissues comparing between lean and overweight/obese subjects. Total RNA from post-mortem subcutaneous adipose tissue was extracted and its quantity and integrity were evaluated using a bioanalyzer before being reverse transcribed to cDNA. Then, by using SYBR-green as a fluorophore detection, quantitative real-time PCR was performed. The relative expression of each target gene was calculated using the comparative 2-∆∆Ct method, and the expression levels of target genes were normalized to that of GAPDH, RPLP0, and HPRT1. Mean differences of AMPK subunits mRNA level for both lean and overweight/obese subjects were determined by Mann-Whitney for two-sample comparisons using SPSS 26.0 (SPSS Inc., USA). This study revealed that in overweight/obese subjects, the gene expression of α1-AMPK was upregulated (2.5-fold) whilst α2-AMPK was downregulated (0.5-fold) when compared to lean controls (p=0.044). There were no differences observed between the β and γ subunits in both lean and overweight/obese subjects. Findings from this study suggests that α1- and α2-AMPK gene expression plays an important role in overweight/obese subjects. Future studies to explore the AMPK gene expressions in visceral adipose tissue and among underweight subjects would further close this knowledge gap.