Document Detail


Glucose regulation of thrombospondin and its role in the modulation of smooth muscle cell proliferation.
MedLine Citation:
PMID:  20689700     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Smooth muscle cells (SMC) maintained in high glucose are more responsive to IGF-I than those in normal glucose. There is significantly more thrombospondin-1 (TSP-1) in extracellular matrix surrounding SMC grown in 25 mM glucose. In this study we investigated 1) the mechanism by which glucose regulates TSP-1 levels and 2) the mechanism by which TS-1 enhances IGF-I signaling. The addition of TSP-1 to primary SMC was sufficient to enhance IGF-I responsiveness in normal glucose. Reducing TSP-1 protein levels inhibited IGF-I signaling in SMC maintained in high glucose. We determined that TSP-1 protected IAP/CD47 from cleavage and thereby facilitated its association with SHP substrate-1 (SHPS-1). We have shown previously that the hyperglycemia induced protection of IAP from cleavage is an important component of the ability of hyperglycemia to enhance IGF-I signaling. Furthermore we determined that TSP-1 also enhanced phosphorylation of the beta3 subunit of the alphaVbeta3 integrin, another molecular event that we have shown are critical for SMC response to IGF-I in high glucose. Our studies also revealed that the difference in the amount of TSP-1 in the two different glucose conditions was due, at least in part, to a difference in the cellular uptake and degradation of TSP-1.
Authors:
Laura A Maile; Lee B Allen; Christopher F Hanzaker; Katherine A Gollahon; Paul Dunbar; David R Clemmons
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-06-20
Journal Detail:
Title:  Experimental diabetes research     Volume:  2010     ISSN:  1687-5303     ISO Abbreviation:  Exp Diabetes Res     Publication Date:  2010  
Date Detail:
Created Date:  2010-08-06     Completed Date:  2010-11-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101274844     Medline TA:  Exp Diabetes Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  -     Citation Subset:  IM    
Affiliation:
Division of Endocrinology, University of North Carolina, CB# 7170, 5030 Burnett Womack, Chapel Hill, NC 27599-7170, USA. laura_maile@med.unc.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Antigens, CD47 / metabolism
Cell Proliferation*
Glucose / metabolism*,  pharmacology
Hyperglycemia / metabolism*
Insulin-Like Growth Factor I / metabolism*
Integrin alphaVbeta3 / metabolism
Male
Myocytes, Smooth Muscle / drug effects,  metabolism,  physiology*
Phosphorylation
Swine
Thrombospondin 1 / metabolism*,  pharmacology
Chemical
Reg. No./Substance:
0/Antigens, CD47; 0/Integrin alphaVbeta3; 0/Thrombospondin 1; 50-99-7/Glucose; 67763-96-6/Insulin-Like Growth Factor I
Comments/Corrections

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