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- Title
High Glucose Prevents Inhibition by Nitric Oxide of Smooth Muscle Cell Migration: Role of SERCA Cysteine-674.
- Authors
Tong, Xiaoyong; Ying, Jia; Weisbrod, Robert M.; Pimentel, David R.; Trucillo, Mario; Xu, Shanqin; Adachi, Takeshi; Cohen, Richard A.
- Abstract
Accelerated atherosclerosis and restenosis, marked by increased vascular smooth muscle cell (VSMC) migration, are major causes of morbidity and mortality in diabetes mellitus (DIM), however, the underlying mechanisms are not clear. Smooth muscle sarco(endo)plasmic reticulum Ca[sup 2+]-ATPase (SERCA) plays a key role in mediating the decrease in intracellular Ca[sup 2+] caused by nitric oxide (NO), and SERCA function is impaired in atherosclerosis and diabetes. NO S-glutathiolates the reactive cysteine-674 in the SERCA, thus increasing SERCA activity, and inhibiting Ca[sup 2+] influx and migration of VSMC. The effect of culture of VSMC in high glucose (HG) was determined by exposing rat aortic VSMC to normal (5.5 mM) or high (25 mM) glucose for 3d. Cell migration over 6h into a wound in the cell monolayer was measured 5 min after adding the NO donor SNAP or 24 h after inducing iNOS with IL-1β. In normal glucose, SNAP or IL-1β significantly inhibited migration in cells transfected with GFP or SERCA WT, but not with a SERCA C674S mutant. After HG, NO failed to inhibit the migration of cells expressing GFP. In contrast, overexpression of SERCA WT, but not the SERCA C674S mutant, maintained the inhibition of migration by NO despite exposing the cells to HG. The iNOS inhibitor, L-NIL, blocked the inhibition of migration by IL-1β confirming the role of endogenous NO. Further studies showed that both biotinylated glutathione and biotinylated-iodoacetamide (BIAM) labeling of SERCA C674 in non-transfected VSMC were decreased by HG. The SOD mimetic, Tempol, increased BIAM labeling of SERCA and restored the ability of NO to inhibit migration in cells exposed to HG. These results suggest that failure of NO to inhibit migration in VSMC exposed to HG is due to oxidation of the SERCA reactive cysteine-674.
- Subjects
BLOOD sugar; NITRIC oxide; SMOOTH muscle; CELL migration; CYSTEINE proteinases; ENDOPLASMIC reticulum
- Publication
Diabetes, 2007, Vol 56, pA190
- ISSN
0012-1797
- Publication type
Article