IRIG: Update on mitochondrial dysfunction in insulin resistance

Mitochondrial dysfunction is observed in insulin resistance and type 2 diabetes. It is proposed as a mechanism for the pathogenesis of insulin resistance in 2004. In the past few years, research on this topic is very active and huge progress has been made. Current literature suggests following two points: (I) mitochondrial dysfunction is a protection mechanism against insulin resistance; (II) mitochondrial inhibition is able to improve insulin sensitivity.  The two points are supported by following literature:  (A) Mitochondrial dysfunction is a result of insulin resistance in most model systems as documented in a review article (1).  (B) All of the clinically approved drugs for insulin sensitization are able to inhibit mitochondrial function.  Inhibition of mitochondrial function by Berberine leads to insulin sensitization through AMPK activation (2). Berberine is an herbal insulin sensitizer that is wildly used in China.  This activity of berberine was confirmed in a later study for AMPK activation, in which berberine was tested together with TZDs and metformin for inhibition of mitochondrial function (3).  In genetic study, inhibition of mitochondrial function by transgenic modification leads to protection of mice from insulin resistance (4).
 
Reference:
            
1. Pagel-Langenickel I, Bao J, Pang L, Sack MN: The role of mitochondria in the pathophysiology of skeletal muscle insulin resistance. Endocr Rev 2010;31:25-51
2. Yin J, Gao Z, Liu D, Liu Z, Ye J: Berberine Improves Glucose Metabolism through Induction of Glycolysis. Am J Physiol Endocrinol Metab 2008;294:E148-E156
3. Hawley SA, Ross FA, Chevtzoff C, Green KA, Evans A, Fogarty S, Towler MC, Brown LJ, Ogunbayo OA, Evans AM, Hardie DG: Use of cells expressing gamma subunit variants to identify diverse mechanisms of AMPK activation. Cell Metab 2010;11:554-565
4. Li J, Romestaing C, Han X, Li Y, Hao X, Wu Y, Sun C, Liu X, Jefferson LS, Xiong J, Lanoue KF, Chang Z, Lynch CJ, Wang H, Shi Y: Cardiolipin remodeling by ALCAT1 links oxidative stress and mitochondrial dysfunction to obesity. Cell Metab 2010;12:154-165
 
By Jim --------------------------------
Jianping Ye, M.D.
Professor of Molecular Biology
Antioxidant and Gene Regulation Lab
PBRC/LSU
E-mail: yej@pbrc.edu
Phone: (225) 763-3163
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