ID factors regulate the ability of Müller glia to become proliferating neurogenic progenitor‐like cells

• Published in: Glia Vol. 72; no. 7; pp. 1236 - 1258
• Main Authors: Taylor, Olivia B., Patel, Snehal P., Hawthorn, Evan C., El‐Hodiri, Heithem M., Fischer, Andy J.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wissley & Sons, Inc 01.07.2024; Wiley Subscription Services, Inc
• Subjects: Animals; Cell Proliferation - drug effects; Cell Proliferation - physiology; Cells (biology); Chick Embryo; Chickens; Cyclin-dependent kinase inhibitor p21; Damage; Down-regulation; Ependymoglial Cells - metabolism; Ependymoglial Cells - physiology; Fibroblast growth factor 2; Glycoprotein gp130; GTP-binding protein; ID factors; Inhibitor of Differentiation Proteins - genetics; Inhibitor of Differentiation Proteins - metabolism; Insulin; Mueller cells; Müller glia; Neural Stem Cells - metabolism; Neurogenesis - drug effects; Neurogenesis - physiology; Neuroglia - metabolism; neuronal differentiation; Neuronal-glial interactions; Offspring; Phenotypes; Progenitor cells; Progeny; regeneration; Retina; Retina - cytology; Retina - metabolism; Stem Cells - metabolism; Stem Cells - physiology; Zebrafish; ID factors; Müller glia; regeneration; retina; neuronal differentiation
• ISSN: 0894-1491; 1098-1136; 1098-1136
• DOI: 10.1002/glia.24523

The purpose of this study was to investigate how ID factors regulate the ability of Müller glia (MG) to reprogram into proliferating MG‐derived progenitor cells (MGPCs) in the chick retina. We found that ID1 is transiently expressed by maturing MG (mMG), whereas ID4 is maintained in mMG in embryonic retinas. In mature retinas, ID4 was prominently expressed by resting MG, but following retinal damage ID4 was rapidly upregulated and then downregulated in MGPCs. By contrast, ID1, ID2, and ID3 were low in resting MG and then upregulated in MGPCs. Inhibition of ID factors following retinal damage decreased numbers of proliferating MGPCs. Inhibition of IDs, after MGPC proliferation, significantly increased numbers of progeny that differentiated as neurons. In damaged or undamaged retinas inhibition of IDs increased levels of p21Cip1 in MG. In response to damage or insulin+FGF2 levels of CDKN1A message and p21Cip1 protein were decreased, absent in proliferating MGPCs, and elevated in MG returning to a resting phenotype. Inhibition of notch‐ or gp130/Jak/Stat‐signaling in damaged retinas increased levels of ID4 but not p21Cip1 in MG. Although ID4 is the predominant isoform expressed by MG in the chick retina, id1 and id2a are predominantly expressed by resting MG and downregulated in activated MG and MGPCs in zebrafish retinas. We conclude that ID factors have a significant impact on regulating the responses of MG to retinal damage, controlling the ability of MG to proliferate by regulating levels of p21Cip1, and suppressing the neurogenic potential of MGPCs. Main Points ID4 transcription is regulated by several pathways that are active during Müller glia reprogramming. ID4 activity is necessary for Müller glia to become progenitor‐like and proliferate, but ID1/2/3 suppresses differentiation of progeny into neuron‐like cells. PERK signaling contributes to an adaptive stress response in OLs after SCI and support white matter protection. In Perk‐/‐ OLs, SCI produces enhanced stress response and result in white matter loss. ROS‐Reactive Oxygen Species, TTI‐Transient Translational Impairment, TF‐Transcription Factors.