- Authors: Kim TJ. et al.
- Year: 2021
- Journal: Biochem Pharmacol
- Applications: in vivo / siRNA / in vivo-jetPEI
For siRNA delivery into the skeletal muscle, AMPKα1 siRNA (100 μg/mouse) was administered twice at 48 h intervals for 8 weeks using in vivo-jetPEI (Cat. No.: 201-50G, Polyplus Transfection, NY, USA) through the tail vein of HFD plus VAL-treated mice. A scrambled siRNA (Cat. No.: sc-37007, Santa Cruz Biotechnology) was injected into each mouse in ND group.
Valdecoxib (VAL), a non-steroidal anti-inflammatory drug, has been widely used for treatment of rheumatoid arthritis, osteoarthritis, and menstrual pain. It is a selective cyclooxygenase-2 inhibitor. The suppressive effects of VAL on cardiovascular diseases and neuroinflammation have been documented; however, its impact on insulin signaling in skeletal muscle has not been studied in detail. The aim of this study was to investigate the effects of VAL on insulin resistance in mouse skeletal muscle. Treatment of C2C12 myocytes with VAL reversed palmitate-induced aggravation of insulin signaling and glucose uptake. Further, VAL attenuated palmitate-induced inflammation and endoplasmic reticulum (ER) stress in a concentration-dependent manner. Treatment with VAL concentration-dependently upregulated AMP-activated protein kinase (AMPK) and heat shock protein beta 1 (HSPB1) expression. In line with in vitro experiments, treatment with VAL augmented AMPK phosphorylation and HSPB1 expression, thereby alleviating high-fat diet-induced insulin resistance along with inflammation and ER stress in mouse skeletal muscle. However, small interfering RNA-mediated inhibition of AMPK abolished the effects of VAL on insulin resistance, inflammation, and ER stress. These results suggest that VAL alleviates insulin resistance through AMPK/HSPB1-mediated inhibition of inflammation and ER stress in skeletal muscle under hyperlipidemic conditions. Hence, VAL could be used as an effective pharmacotherapeutic agent for management of insulin resistance and type 2 diabetes.