Purchase this article with an account.
Valeria E. Lorenc, Susana G. Ortiz, Maria C. Sanchez; Igf-1/igf-1r System Implication In Proliferative Retinopathies. Invest. Ophthalmol. Vis. Sci. 2012;53(14):787.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Insulin-like growth factor-1 (IGF-1) and it's receptor (IGF-1R) are involved during the normal vascular development of the retina as well as in the pathogenesis of retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR). Endothelial cell proliferation is a common feature of these retinopathies. In addition Müller cells (MC) are known to be implicated in these diseases by producing, Vascular Endothelial Growth Factor (VEGF) and IGF-1, among other factors; and by secreting metaloproteinases (MMPs) that participate in the extracellular remodeling. However, at present, it is not well known the function of IGF-1/IGF-1R system during angiogenesis. Previously we have demonstrated that IGF-1 induces the MC migration through IGF-1R activation. This cellular event was associated with IGF-1R activation for long times of IGF-1 stimulation. Herein we investigate the phosphorilate state of IGF-1R for shorter times under IGF-1 stimulus and its intracellular signaling pathway activation. In adition in an "in vivo" model the IGF-1R expression and distribution was examined at different times in retina of animals with and without Oxigen induced retinopathy (OIR).
The human MIO-M1 cell line was used and cultured in presence of 10 nM IGF-1 for different times (1 to 20 minutes). The phosphorilated IGF-1R was analyzed by Western blot. Using a specific monoclonal antibody to demonstrate the specificity of the IGF-1 activation, cells were pre-incubated with anti IGF-1R antibody (αIR3) and p-IGF-1R was evaluated by WB. Retinas from animals with and without OIR were analized for IGF-1R expression at selected time points (P3, P10, P12 and P15). The localization of IGF-1R was examined by inmunofluorescence and confocal microscopy. Different retinal cell types were characterized using cell markers.
By Western blot we observed that, under IGF-1 stimulus, IGF-1R was rapidily phosphorilated from minute 1 since IGF-1 induction. In adition this phosphorilation was fully blocked by IGF-1R antibody, indicating that this phosphorilation was produced by IGF-1 binding to its cognitive receptor. In the in vivo model IGF-1R was expressed in the inner and outer nuclear layers as well as in blood vessels. This expression showed significant changes during retinal development and with the induction of retinopathy.
These results demonstrate, in the in vitro model, the specific activation of IGF-1R by IGF-1; as well as, in the in vivo model, the IGF-1R distribution.
This PDF is available to Subscribers Only