Impact of Adenosine Analogue, Adenosine-5'-N-Ethyluronamide (NECA), on Insulin Signaling in Skeletal Muscle Cells.

Mansour Haddad,Yassine Chtourou

doi:10.1155/2021/9979768

Abstract

Materials and Methods Rat L6 skeletal muscle cells were cultured in 25 cm2 flasks. These differentiated cells were treated, and then, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) (probe-based) was used to measure the relative mRNA expression level for metabolic, inflammatory, and nuclear receptor genes including peroxisome proliferator-activated receptor gamma (PGC-1α), carnitine palmitoyl transferase 1 beta (CPT1B), long-chain acyl-CoA de hydrogenase (LCAD), acetyl-CoA carboxylase beta (ACCβ), pyruvate dehydrogenase kinase 4 (PDK4), hexokinase II (HKII), phosphofructokinase (PFK), interleukin-6 (IL-6), and nuclear receptor subfamily 4, group A (NR4A) at different treatment conditions. Results Adenosine-5′-N-ethyluronamide (NECA), a stable adenosine analogue, significantly stimulate inflammatory mediator (IL-6) (p < 0.001) and nuclear receptors (NR4A) (p < 0.05) and significantly modulate metabolic (PFK, LCAD, PGC-1α, and CPT1B) gene expressions in skeletal muscle cells (p < 0.05, p < 0.05, p < 0.001, and p < 0.01, respectively). This present study shows that there is a noteworthy crosstalk between NECA and insulin at various metabolic levels including glycolysis (HKII), fatty acid oxidation (ACCβ), and insulin sensitivity (PDK4). Conclusions A novel crosstalk between adenosine analogue and insulin has been demonstrated for the first time; evidence has been gathered in vitro for the effects of NECA and insulin treatment on intracellular signaling pathways, in particular glycolysis and insulin sensitivity in skeletal muscle cells.

Highlights

Numerous experimental data indicate that adenosine can affect insulin-mediated metabolic processes in skeletal muscle cells [1,2,3]
The major novel findings in the present study are as follows: (i) stable adenosine analogue, NECA, increases gene expressions involved in inflammation (IL-6), nuclear receptors (NR4A; NR4A1), glycolysis (PFK), and energy metabolism (PGC-1α), while modulating gene expression involved in fatty acid transport and oxidation (LCAD and carnitine palmitoyl transferase 1 beta (CPT1B)); (ii) NECA and insulin together decrease gene expression involved in insulin sensitivity (PDK4) and increase gene expression implicated in glycolysis (HKII) and fatty acid oxidation (ACCβ); and (iii) insulin alone had no effect on the gene expression in one week starved cells
This present study has demonstrated that one-week starved skeletal muscle cells in vitro exhibited a marked resistance to the effect of insulin on metabolic and inflammatory genes: this further confirms the findings reported by many researchers who found that starvation induced insulin resistance [29, 30]

Summary

Introduction

Numerous experimental data indicate that adenosine can affect insulin-mediated metabolic processes in skeletal muscle cells [1,2,3]. Adenosine-5′-N-ethyluronamide (NECA), a stable adenosine analogue, significantly stimulate inflammatory mediator (IL-6) (p < 0:001) and nuclear receptors (NR4A) (p < 0:05) and significantly modulate metabolic (PFK, LCAD, PGC-1α, and CPT1B) gene expressions in skeletal muscle cells (p < 0:05, p < 0:05, p < 0:001, and p < 0:01, respectively). This present study shows that there is a noteworthy crosstalk between NECA and insulin at various metabolic levels including glycolysis (HKII), fatty acid oxidation (ACCβ), and insulin sensitivity (PDK4). A novel crosstalk between adenosine analogue and insulin has been demonstrated for the first time; evidence has been gathered in vitro for the effects of NECA and insulin treatment on intracellular signaling pathways, in particular glycolysis and insulin sensitivity in skeletal muscle cells

Methods

Results

Discussion

Conclusion