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Sugata Hazra, Yagna P. Jarajapu, Sergio Caballero, Li Liu, Valerie Stepps, Ashay Bhatwadekar, Michael E. Boulton, Paul J. Higgins, Stephen H. Bartelmez, Maria Grant; Plasminogen Activator Inhibitor (PAI)-1: Potential Therapeutic Target For Autologous Cell Therapy For Treatment Of Macular Ischemia (MI) And Vasodegenerative Phase Of Diabetic Retinopathy (DR). Invest. Ophthalmol. Vis. Sci. 2011;52(14):3179.
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© ARVO (1962-2015); The Authors (2016-present)
The dysfunction of human diabetic(D) CD34+ endothelial progenitor cells limits their utility in autologous cell therapy for vascular complications such as MI and DR. Previously, we showed that transient inhibition of transforming growth factor-beta 1 (TGF-β1) enhances vascular reparative function of human DCD34+ cells . Expression of PAI-1, the major gene product of TGF-β1 activation, is increased by high glucose and insulin exposure and in the serum of diabetics. We tested whether the beneficial effects of TGF-β1 blockade on CD34+ cells function were mediated by inhibition of PAI-1 and whether blocking PAI-1 could correct diabetes associated dysfunction of these cells.
Plasma determinations of PAI-1 and TGF-β1 were compared in type(T)2 and T1D patients. CD34+ cells from these individuals were isolated and analyzed for cell survival (in presence and absence of growth factors), proliferation, cell cycle analysis and migration. The effect of TGF-β1 phosphorodiamidate morpholino oligomers (PMO) treatment on PAI-1 level was determined in CD34+ cells.PAI-1 was blocked using either lentivirus expressing PAI-1 shRNA or PAI-1 siRNA. In vivo homing ability of PAI-1 inhibited cells was assessed using an ocular model of ischemia/reperfusion (I/R) injury.
Plasma PAI-1 level was increased in T2D patients compared to T1D (p<0.05) and directly correlated with TGF-β1 plasma levels (r= 0.44).TGF-β1 PMO treatment resulted in a reduction of PAI-1 mRNA expression (p<0.05). PAI-1 blockade 1) promoted G0-G1transition of these cells resulting in enhanced EPC proliferation in vitro even in the absence of growth factors (p<0. 05); 2) bypassed the inhibitory effect of TGF-β1 on cell survival (p<0.001); facilitated 3) increased migration in response to SDF-1α (p<0.01); and 4) improved in vivo re-endothelialization in the I/R model.
Our results suggest that the cytostatic activity of TGF-β1 in CD34+ cells is mediated largely through PAI-1 inhibition. Blocking PAI-1 corrects multiple defects in CD34+ cells from T2D patients. This approach may offer a promising therapeutic strategy for restoring vascular reparative function in diabetic cells and facilitate their use in autologous cell therapy for MI or DR.
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