Cell Therapy Model of Diabetic Retinopathy Using Vascular Progenitor Cells Derived from Human iPSC

Abstract

Purpose : Successful cellular therapy of diabetic vascular complications (DVC) will require novel sources of angiogenic progenitors that can sustain long-term functional recovery in a clinical setting. Since adult stem cell sources such as diabetic endothelial progenitor cells (D-EPC) have proven to be scarce or have impaired migration into the injury sites, human induced pluripotent stem cell (hiPSC) technology may offer unlimited amounts of embryonic vascular progenitor (VP) to repair ischemic diabetic tissues with clinically relevant and efficient protocols for reprogramming and differentiation.

Methods : To test this potential, we generated diabetic iPSC (D-iPSC) from skin fibroblasts of type-I diabetic patient using non-integrative episomal reprogramming system. Short exposure to a GSK3β inhibitor and ascorbic acid dramatically facilitated the reprogramming kinetics. Additionally, we recently developed novel chemical methods [LIF with GSK3β, ERK and tankyrase inhibitors (L3i)] that stably revert hPSC to a mouse ESC-like naïve state. We demonstrated that LIF-3i-reverted hPSC acquired transcriptomic, epigenetic, and signaling signatures of naïve-pluripotency, and significantly improved multi-lineage differentiation efficiencies with reduced lineage bias.

Results : This L3i reversion method was successfully applied to generating naïve D-iPSC to obtain higher quality of therapeutic VP. Primed- (traditional) and naïve-D-iPSC were compared for differentiation potential, vascular functional assays in vitro and in vivo. To investigate the regenerative capacity of iPSC-VP in a DVC-relevant model, we employed a streptozotocin (STZ) injected diabetic athymic nude rat model that exhibited hyperglycemia over 24 weeks and decreased retinal function as measured by electroretinography. Our preliminary results showed that injection of healthy hiPSC-VP into this diabetic rat model validated human cell capacity to migrate and engraft to injured sites. We are currently examining the engraftment of D-iPSC-VP, naïve-D-iPSC-VP, healthy cord blood- and fibroblast-iPSC-VP. Furthermore, intravitreous injection of hiPSC-VP expressing a luciferase transgene allowed detection of human cell migration using noninvasive live animal bioluminescent imaging.

Conclusions : This STZ-induced diabetic rat model provides a translational opportunity to evaluate the use of patient specific iPSC-VP for treatment of DVC.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.