SiRNA strategy against overexpression of extracellular matrix in diabetic retinopathy.

Increased synthesis of extracellular matrix (ECM) contributes to the development of vascular BM thickening, a prominent abnormality in diabetic retinopathy. RNA interference (RNAi) approach was used in this study to examine the effect of small interfering RNAs (siRNAs) for their ability to inhibit ECM-specific gene overexpression under high glucose condition in rat microvascular endothelial cells (RMECs). Four fibronectin (FN)-siRNAs, three collagen IV (Coll IV)-siRNAs, and four laminin (LM)-siRNAs, a total of 11 siRNAs were screened. RMECs were transfected with 10, 30, or 100 nm of each siRNAs in the presence of 8 microm lipofectin and subjected to analysis 72 hr after transfection. In long-term studies siRNA-transfected cells were examined after 12 days. Two FN siRNAs, two Coll IV siRNAs, and two LM siRNAs significantly reduced the respective target expressions. Findings from this study indicate that high glucose-induced abnormal expression of BM components may contribute to increased vascular permeability. SiRNA may be a useful tool in preventing excess vascular permeability, a characteristic feature of early diabetic retinopathy.