Abstract
Purpose :
In a murine model of diabetic retinopathy (DR), intravitreal injection of human CD34+ stem cells from bone marrow(BMSCs) was associated with the preservation of retinal vasculature. Since miRNAs(miRNA) have been implicated to play a role in the pathogenesis of DR, this study tested the hypothesis that intravitreal injection of human CD34+BMSCs alters miRNA expression patterns in the recipient retina in eyes with DR.
Methods :
Streptozotocin-induced diabetic mice(C57BL/6J) were used as a model for diabetic retinopathy with chronic systemic immunosuppression using Tacrolimus and Rapamycin to avoid rejection of human cells. Human CD34+BMSCs were harvested from the mononuclear cell fraction of bone marrow from a healthy donor using magnetic beads. The right eye of each mouse received an intravitreal injection of 50,000 healthy CD34+ BMSCs or phosphate buffered saline(PBS). After one week time point, the mice were euthanized, and the eyes were removed for microarray analysis of the retina. Ingenuity Pathway Analysis (IPA) was used to identify activated pathways.
Results :
Microarray expression analysis showed changes in the expression of 11 miRNAs in the murine retina following CD34+BMSC injection compared to PBS-injected control. Two of these miRNAs are known to be involved in DR pathogenesis: let7c-1 (FC= -1.53, p<0.01) and mir-455 (FC=1.5, p< 0.01). Downregulation of let-7c has been seen in diabetic microvascular complications, while upregulation of miR-455-5p attenuates high glucose-triggered oxidative stress injury. IPA identified that the top canonical activated pathway was “HOTAIR Regulatory Pathways,” which can be modulated by let-7c-1. Potential targeting of long non-coding(lnc) RNA HOTAIR by microRNAs is a novel finding for DR – this lncRNA has been implicated in promoting apoptosis, inhibiting cell metastasis, and angiogenesis in cancer, but not yet in diabetic retinopathy.
Conclusions :
Gene expression analysis showed that intravitreal injection of CD34+BMSCs harvested from a healthy donor has a robust effect on miRNA expression in the murine retina with DR. Expression of specific miRNAs implicated in the pathogenesis of DR was affected, including let-7 and miR-455. Both miRNAs play important roles in regulating the lncRNA HOTAIR pathway that affects endothelial cell dysfunction and indirectly affects VEGFA transcription.
This is a 2021 ARVO Annual Meeting abstract.