Genetic loss of function of Ptbp1 does not induce glia-to-neuron conversion in retina
Thanh Hoang, Dong Won Kim, Haley Appel, Nicole Pannullo, Patrick J. Leavey, Manabu Ozawa, Sika Zheng, Minzhong Yu, Neal S. Peachey, Seth Blackshaw
Abstract
Direct reprogramming of glia into neurons is a potentially promising approach for the replacement of neurons lost to injury or neurodegenerative disorders. Knockdown of the polypyrimidine tract-binding protein Ptbp1 has been recently reported to induce efficient conversion of retinal Mϋller glia into functional neurons. Here, we use a combination of genetic lineage tracing, single-cell RNA sequencing (scRNA-seq), and electroretinogram analysis to show that selective induction of either heterozygous or homozygous loss-of-function mutants of Ptbp1 in adult retinal Mϋller glia does not lead to any detectable level of neuronal conversion. Only a few changes in gene expression are observed in Mϋller glia following Ptbp1 deletion, and glial identity is maintained. These findings highlight the importance of using genetic manipulation and lineage-tracing methods in studying cell-type conversion.