Referenced in: none

Automatically associated channels: Kir2.3 , Kir2.4 , Kir3.4 , SK3

Title: Glycogen Synthase Kinase-3β Inhibition Ameliorates Cardiac Parasympathetic Dysfunction in Type 1 Diabetic Akita Mice.

Authors: Yali Zhang, Charles M Welzig, Kristen Picard, Chuang Du, Bo Wang, John Kyriakis, Mark Aronovitz, William Claycomb, Robert Blanton, Ho-Jin Park, Jonas B Galper

Journal, date & volume: Diabetes, 2014 Jan 23 , ,

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/24458356

Abstract
Decreased heart rate variability (HRV) is a major risk factor for sudden death and cardiovascular disease. We previously demonstrated that parasympathetic dysfunction in the heart of the Akita type 1 diabetic mouse was due to a decrease in the level of the sterol response element-binding protein (SREBP-1). Here we demonstrate that hyperactivity of glycogen synthase kinase-3β (GSK3β) in the atrium of the Akita mouse results in decreased SREBP-1, attenuation of parasympathetic modulation of heart rate, measured as a decrease in the high-frequency (HF) fraction of HRV in the presence of propranolol, and a decrease in expression of the G-protein coupled inward rectifying K(+) (GIRK4) subunit of the acetylcholine (ACh)-activated inward-rectifying K(+) channel (IKACh), the ion channel that mediates the heart rate response to parasympathetic stimulation. Treatment of atrial myocytes with the GSK3β inhibitor Kenpaullone increased levels of SREBP-1 and expression of GIRK4 and IKACh, whereas a dominant-active GSK3β mutant decreased SREBP-1 and GIRK4 expression. In Akita mice treated with GSK3β inhibitors Li(+) and/or CHIR-99021, Li(+) increased IKACh, and Li(+) and CHIR-99021 both partially reversed the decrease in HF fraction while increasing GIRK4 and SREBP-1 expression. These data support the conclusion that increased GSK3β activity in the type 1 diabetic heart plays a critical role in parasympathetic dysfunction through an effect on SREBP-1, supporting GSK3β as a new therapeutic target for diabetic autonomic neuropathy.