Transplantation of NTPDase2-positive Sorted Müller Glial Cells into the Mouse Retina

Tissue-specific progenitor cells form a potential population for cell-based transplantation therapy. Müller glial cells are suggested to contain, or represent the progenitor pool in the retina and can dedifferentiate and regenerate neuronal cells in fish and amphibians. However, the Müller glial cells of mammals have a more limited regenerative capacity in response to injury and disease. Transplantation experiments with Müller glial cells have shown limited success. In this study we transplant NTPDase2- positive Müller glial cells labelled with CellTracker Green or NTPDase2-positive Müller glial cells sorted from transgenic tdTomato mouse retina. We found that NTPDase2-sorted Müller glial cells do not have the intrinsic capacity to integrate into the mouse retina upon subretinal injection under the conditions used. Interestingly, we also found that CellTracker Green labelled NTPDase2-sorted Müller glial cells release CellTracker Green conjugates. NTPDase2-sorted negative cells do not. Injection of CellTracker Green alone did not lead to labelling of any retinal cell types. However, when NTPDase2-sorted cells are injected into the mouse retina these conjugates are preferentially taken up by Starburst amacrine cells. This highlights a potentially novel import transporter on the plasma membrane of Starburst amacrine cells.