Cardiovascular Research Advance Access first published online on March 4, 2009
This version [Corrected Proof] published online on March 27, 2009
Cardiovascular Research, doi:10.1093/cvr/cvp082
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p66ShcA modulates oxidative stress and survival of endothelial progenitor cells in response to high glucose
1 Laboratorio di Cardiologia Molecolare, IRCCS-Policlinico San Donato, San Donato Milanese, Milan, Italy
2 Laboratorio di Patologia Vascolare, Istituto Dermopatico dell'Immacolata-IRCCS, Via dei Monti di Creta 104, 00167 Rome, Italy
* Corresponding author. Tel: +39 0666462431; fax: +39 0666462430. E-mail address: f.martelli{at}idi.it
Aims: A close relationship exists between hyperglycaemia, oxidative stress, and diabetic complications. In fact, high glucose (HG) determines the overproduction of reactive oxygen species (ROS) by the mitochondria. p66ShcA is a gene that regulates the apoptotic responses to oxidative stress. Indeed, p66ShcA knockout (ko) mice display decreased ROS production and increased resistance to ROS-induced cell death in a variety of pathophysiological settings. Reduced endothelial progenitor cell (EPC) number, differentiation, and function are relevant components of the angiogenesis impairment observed in diabetic patients. We examined the role of p66ShcA in the EPC deficit induced by HG.
Methods and results: Mouse bone marrow-derived c-kit+ cells differentiate in endothelial-like cells when plated on fibronectin (BM-derived EPCs). We found that cell culture in the presence of HG up-regulated p66ShcA protein expression and that HG exposure markedly decreased the number of BM-derived EPCs. Conversely, p66ShcA ko BM-derived EPCs were not sensitive to HG inhibition. Indeed, the resistance of p66ShcA ko BM-derived EPCs to HG was associated with reduced levels of both apoptosis and oxidative stress. To functionally link the HG response to ROS production, p66ShcA ko BM-derived EPCs were reconstituted either with p66ShcA wild-type (wt) or with a p66ShcA allele (p66ShcA qq) that was devoid of its ROS-generating function. We found that only p66ShcA wt and not the qq mutant rescued p66ShcA ko cell sensitivity to HG. One major feature of oxidative stress is its ability to reduce the bio-availability of nitric oxide (NO) that, in turn, plays a crucial role in endothelial differentiation and function. We found that the p66ShcA deletion prevented the HG-induced increase of nitrotyrosine, and that the resistance to HG of p66ShcA ko BM-derived EPCs was prevented by NO synthase inhibition. With a reciprocal approach, the treatment of p66ShcA wt cells with a NO donor prevented the HG-induced deficit. Finally, using a Matrigel plug angiogenesis assay, we demonstrated that p66ShcA ko prevented diabetic impairment of angiogenesis in vivo.
Conclusion: p66ShcA deletion rescues the BM-derived EPCs defect induced by HG, indicating p66ShcA as a potential therapeutic target in diabetic vasculopathy.
KEYWORDS Diabetes; Oxygen radicals; Stem cells; Endothelium; Apoptosis
Time for primary review: 24 days
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Cardiovasc Res 2009 82: 388-389.
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  J. Sainz and M. Sata When p66ShcA is away, mice EPCs sweetly play Cardiovasc Res, June 1, 2009; 82(3): 388 - 389. [Full Text] [PDF]
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