Astragalus polysaccharide improves palmitate-induced insulin resistance by inhibiting PTP1B and NF-κB in C2C12 myotubes.
We investigated the effects of Astragalus polysaccharide (APS) on palmitate-induced insulin resistance in C2C12 skeletal muscle myotubes. Palmitate-reduced glucose uptake was restored by APS. APS prevented palmitate-induced C2C12 myotubes from impaired insulin signaling by inhibiting Ser307 phosphorylation of insulin receptor substrate-1 (IRS-1) and increasing Ser473 phosphorylation of Akt. Moreover, the increases in protein-tyrosine phosphatase-1B (PTP1B) protein level and NF-κB activation associated with palmitate treatment were also prevented by APS. However the treatment with APS didn't change AMP-activated protein kinase (AMPK) activation in palmitate-induced myotubes. The results of the present study suggest that Astragalus polysaccharide inhibits palmitate-induced insulin resistance in C2C12 myotubes by inhibiting expression of PTP1B and regulating NF-κB but not AMPK pathway.
Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100191, China.
Ming
M
Zhao
Zhao-Feng
ZF
Zhang
Ye
Y
Ding
Jun-Bo
JB
Wang
Yong
Y
Li
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000818:Animals; D027883:Astragalus Plant / Q000737:chemistry*; D002460:Cell Line; D005947:Glucose / Q000378:metabolism; D007333:Insulin Resistance; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D010168:Palmitates / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011134:Polysaccharides / Q000494:pharmacology*; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors*; D015398:Signal Transduction / Q000187:drug effects
D016328:NF-kappa B; D010168:Palmitates; D011134:Polysaccharides; D055372:AMP-Activated Protein Kinases; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D005947:Glucose