title: PPARγ activation improves the molecular and functional components of I(to) remodeling by angiotensin II.
abstract: Patients with diabetes exhibit significantly altered renin-angiotensin system (RAS) control. Recently, it has been determined that hyperglycemic conditions induce an increase in angiotensin II (AT II) expression; specifically by cardiomyocytes. Altered RAS has been shown to be associated with an increase in oxidative stress and cardiac dysfunction leading to the development of cardiac hypertrophy. The transient outward potassium current (I(to)) in cardiac myocytes is mainly mediated by members of the Kv subfamily of voltage gated potassium channels and has been shown to be altered in cellular localization and expression during the development of cardiac hypertrophy. However it is not clear as to how AT II affects the pore forming complex at the cell membrane and thus directly affects the I(to) current. In the current study, we explored the protective effect of PPARγ ligands on cardiomyocyte I(to) by preventing NADPH Oxidase activation and the ensuing ROS formation. Furthermore, short term PPARγ activation in diabetic leptin deficient db/db mice displayed improvements in the membrane association of the molecular components of I(to) as well as prolonged QT interval. These findings demonstrate that PPARγ agonists have the potential to attenuate cardiomyocyte dysfunction associated with diabetes.
authors: Department of Pharmacal Sciences, PPAR and Metabolic Research Lab, Auburn University, Auburn, Alabama 36849, USA.
authors: Gayani
authors: G
authors: Nanayakkara
authors: Nilmini
authors: N
authors: Viswaprakash
authors: Juming
authors: J
authors: Zhong
authors: Thiruchelvan
authors: T
authors: Kariharan
authors: John
authors: J
authors: Quindry
authors: Rajesh
authors: R
authors: Amin
mesh_terms: D000804:Angiotensin II / Q000096:biosynthesis / Q000378:metabolism*; D000818:Animals; D064752:Atrial Remodeling / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002478:Cells, Cultured; D058065:Diabetic Cardiomyopathies / Q000378:metabolism / Q000517:prevention & control*; D015536:Down-Regulation / Q000187:drug effects; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D047495:PPAR gamma / Q000819:agonists* / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000627:therapeutic use; D020257:Ventricular Remodeling / Q000187:drug effects
chemical_list: D002316:Cardiotonic Agents; D007004:Hypoglycemic Agents; D047495:PPAR gamma; D024642:Potassium Channels, Voltage-Gated; D044140:Receptor, Angiotensin, Type 1; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D000804:Angiotensin II