Induction of heat shock proteins may combat insulin resistance.
The molecular mechanism responsible for obesity-associated insulin resistance has been partially clarified: increased fatty acid levels in muscle fibers promote diacylglycerol synthesis, which activates certain isoforms of protein kinase C (PKC). This in turn triggers a kinase cascade which activates both IkappaB kinase-beta (IKK-beta) and c-Jun N-terminal kinase (JNK), each of which can phosphorylate a key serine residue in IRS-1, rendering it a poor substrate for the activated insulin receptor. Heat shock proteins Hsp27 and Hsp72 have the potential to prevent the activation of IKK-beta and JNK, respectively; this suggests that induction of heat shock proteins may blunt the adverse impact of fat overexposure on insulin function. Indeed, bimoclomol--a heat shock protein co-inducer being developed for treatment of diabetic neuropathy--and lipoic acid--suspected to be a heat shock protein inducer--have each demonstrated favorable effects on the insulin sensitivity of obese rodents, and parenteral lipoic acid is reported to improve the insulin sensitivity of type 2 diabetics. Moreover, there is reason to believe that heat shock protein induction may have a favorable impact on the microvascular complications of diabetes, and on the increased risk for macrovascular disease associated with diabetes and insulin resistance syndrome. Heat shock protein induction may also have potential for preventing or treating neurodegenerative disorders, controlling inflammation, and possibly even slowing the aging process. The possible complementarity of bimoclomol and lipoic acid for heat shock protein induction should be assessed, and further efforts to identify well-tolerated agents active in this regard are warranted.
McCarty
Mark F
MF
Natural Alternatives International, 1185 Linda Vista Dr., San Marcos, CA 92078, USA. mccarty@pantox.com
D003924:Diabetes Mellitus, Type 2 / Q000628:therapy; D004789:Enzyme Activation; D055551:HSP27 Heat-Shock Proteins; D050884:HSP72 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D007094:Imides / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D008063:Thioctic Acid / Q000378:metabolism / Q000494:pharmacology
D055551:HSP27 Heat-Shock Proteins; D050884:HSP72 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D007094:Imides; D007328:Insulin; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D011725:Pyridines; D008063:Thioctic Acid; C108730:bimoclomol; D051550:I-kappa B Kinase; D011493:Protein Kinase C; D048670:MAP Kinase Kinase 4