Skip to main content
. Author manuscript; available in PMC: 2011 Jun 1.
Published in final edited form as: Int J Biochem Cell Biol. 2010 Feb 23;42(6):965–974. doi: 10.1016/j.biocel.2010.02.009

Figure 4. Role for the β3 integrin ligand thrombospondin (TSP-1) in the effects of hyperglycemia on SMCs.

Figure 4

Immunoblots from aortas isolated from control or diabetic mice or SMCs cultured under euglycemic (5 mM) or hyperglycemic (25 mM) conditions. The fold increase in TSP-1 levels relative to the values in euglycemic conditions are presented as the mean ± SE from three experiments (A). Exposure of SMCs cultured under euglycemic conditions to TSP-1 triggers ERK activation in a PKCβ and integrin β3-dependent manner. The results are presented as the level of phosphorylated/total protein normalized to results obtained in euglycemic conditions and are graphed as the mean ± SE from three independent experiments (B). Diabetic mice lacking TSP-1 (Thbs1−/−) do not upregulate ERK activation; similarly, Thbs1−/− SMCs do not upregulate ERK activation when cultured in 25 mM glucose (C). No increase in PKCβ is observed in integrin β3-immunoprecipitates from aortas of diabetic Thbs1−/− mice (D) or Thbs1−/−cells cultured in 25 mM glucose (E). The addition of TSP-1 to SMCs cultured in euglycemic conditions (5 mM) promotes the association of PKCβ with integrin β3 (F). Inhibitors used were as follows: MEK (U0126, 10µM), PKCβ (3-(1-(3-Imidazol-1-ylpropyl)-1H-indol-3-yl)-4-anilino-1H-pyrrole-2,5-dione, 5nM), integrin (echistatin, 10µM) and anti-β3 antibody (10µg/ml), control antibody (10µg/ml). Results are representative of those obtained in 3 independent experiments. *P<0.001 as compared to corresponding control.