Abstract
Purpose :
During retinal development, the cell cycle progression of retinal progenitor cells (RPCs) needs to be tightly controlled to ensure proper cell differentiation. CDKs (cyclin-dependent kinases), cyclins, CDK inhibitors, and several transcription factors are known to play key roles in regulating the cell cycle progression of RPCs. We looked for mechanisms that can bridge the regulation at the protein/kinase and transcriptional levels, and propose to elucidate the roles of post-transcriptional m6A (N6-Methyladenosine) modification of mRNAs in regulating RPCs cell cycle.
Methods :
We conditionally knocked out m6A writer methyltransferase-like 14 (METTL14) from the beginning of retinal development. The histology of the METTL14 conditional knock-out (CKO) retinas was evaluated and compared to wild-type retinas at different development stages. The proliferation of RPCs was assessed by EdU cell proliferation assay. Cell cycle analysis was conducted by Fluorescence-activated cell sorting flow cytometry (FACs). RPCs lineage tracing was performed using retroviruses. The m6A high-throughput sequencing (m6A-seq) and single-cell sequencing technology were used to map out the differential gene expression profiles and the downstream signaling pathways.
Results :
We found that the genes involved in directing m6A modification are expressed in the mouse retina. Mettl14 CKO retinas showed abnormal RPCs cell cycle arrest at neonatal stages. The majority of these arrested RPCs underwent apoptosis. A small fraction of them can bypass the apoptosis pathway and differentiate mainly into Müller cells. We further identified the m6A modified genes in the retina via m6A-seq and single-cell RNA-seq and uncovered their potential roles in regulating the RPCs cell cycle.
Conclusions :
Our work demonstrates that epitranscriptomic m6A modification is essential for regulating the RPCs cell cycle during development. Manipulation of the m6A modification pathways may provide promising control of abnormal cell proliferation observed in some retinal diseases.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.