Gene Expression Profiling In Endothelial Progenitor Cells (EPCs) Identifies Novel Transcripts Upregulated In Diabetic Patients Protected From Development Of Diabetic Retinopathy (DR)

Abstract

Purpose: : Rarely are diabetic patients who have long standing disease (>20 yrs) and poor glucose control (9-11% HbA1c) absent of diabetic complications. Why such individuals remain protected is unknown, we postulated that the EPCs of these patients have a more robust reparative potential compared to patients who develop DR. To study this hypothesis we performed gene array analysis on EPCs from this unique patient population and compared to matched diabetics with DR

Methods: : Peripheral blood CD34+ EPCs were isolated from following groups A) patients with no DR (n=5) B) patients with severe nonproliferative DR (NPDR) (n=5) C) non-diabetic control group (n=5). RNA was extracted using Trizol followed by AffyNugen amplification, and cDNA was probed to Human RSTA Affymetrix 2.0 chip. After normalization, data was analyzed using one way ANOVA and changes in gene expression were studied using pathway analysis software. The expression of selected genes was confirmed by RT-PCR.

Results: : There was a robust gene signature of CD34+ cells, ~1000 transcripts significantly separated diabetic patients from controls (p<0.001, FDR 5.5%) and of these, 857 were up-regulated and 90 were down-regulated. 121 genes were up-regulated in diabetic patients with no DR as compared to patients with severe NPDR. Pathway analysis of transcripts showed increased expression of FOXO transcription factors, protective arm of the renin angiotensin system (ACE2, MAS, Apelin, Apelin receptor), and decreased expression of TGFβ1-PAI-1 pathway, all of which play a key role in EPC survival, migration, differentiation, adhesion and proliferation.

Conclusions: : Our data shows that EPC from patients protected from DR compared to those with severe NPDR have a unique gene expression signature including genes that enhance EPC reparative function and identifies potentially new targets for therapy for DR.

Keywords: diabetic retinopathy • gene microarray