Characterization of retinal ganglion cell, horizontal cell, and amacrine cell types expressing the neurotrophic receptor tyrosine kinase Ret

Abstract

We report the retinal expression pattern of Ret, a receptor tyrosine kinase for the glial derived neurotrophic factor (GDNF) family ligands (GFLs), during development and in the adult mouse. Ret is initially expressed in retinal ganglion cells (RGCs), followed by horizontal cells (HCs) and amacrine cells (ACs), beginning with the early stages of postmitotic development. Ret expression persists in all three classes of neurons in the adult. Using RNA sequencing, immunostaining and random sparse recombination, we show that Ret is expressed in at least three distinct types of ACs, and ten types of RGCs. Using intersectional genetics, we describe the dendritic arbor morphologies of RGC types expressing Ret in combination with each of the three members of the POU4f/Brn3 family of transcription factors. Ret expression overlaps with Brn3a in 4 RGC types, with Brn3b in 5 RGC types, and with Brn3c in one RGC type, respectively. Ret RGCs project to the lateral geniculate nucleus (LGN), pretectal area (PTA) and superior colliculus (SC), and avoid the suprachiasmatic nucleus and accessory optic system. Brn3a Ret and Brn3c Ret RGCs project preferentially to contralateral retinorecipient areas, while Brn3b Ret RGCs shows minor ipsilateral projections to the olivary pretectal nucleus and the LGN. Our findings establish intersectional genetic approaches for the anatomic and developmental characterization of individual Ret RGC types. In addition, they provide necessary information for addressing the potential interplay between GDNF neurotrophic signaling and transcriptional regulation in RGC type specification.

Differential expression and subcellular localization of Copines in mouse retina

“…(b) Mouse AP antibody (VIB, Gent, Belgium) is also raised against the human PLAP. It has been previously shown to co‐label the transgenic lines expressing the AP reporter (Parmhans et al, ).…”

“…Brn3b antibody was generated in-house. It has been described previously (Parmhans, Sajgo, Niu, Luo, & Badea, 2018;Xiang et al, 1993;Xiang et al, 1995). A GST fused recombinant peptide with amino acids 184-252 of human Brn3b was used to immunize the rabbits.…”

Genetic Interplay Between Transcription Factor Pou4f1/Brn3a and Neurotrophin Receptor Ret In Retinal Ganglion Cell Type Specification

“…Mouse retinas were stained, processed, and imaged, and RGC dendritic arbors were traced and quantified as described previously 1,51,54 . Briefly, animals were anesthetized, fixed by intracardiac perfusion with 4% Paraformaldehyde (PFA).…”

“…Ret and Neurturin mutants affect photoreceptor light responses and lead to morphological defects of photoreceptors, bipolar and horizontal cell contacts in the outer plexiform layer 48 . Ret is dynamically expressed in specific retinal cell populations, beginning with RGCs (E13 -14.5), followed by Horizontal (E17) and Amacrine (P1) cells [49][50][51] . In the adult retina, Ret is co-expressed with Brn3a predominantly in three mono-and two bistratified subtypes of RGCs, with Brn3b -in four mono-and two bistratified subtypes, and with Brn3c -in a single monostratified subpopulation.…”

“…In the adult retina, Ret is co-expressed with Brn3a predominantly in three mono-and two bistratified subtypes of RGCs, with Brn3b -in four mono-and two bistratified subtypes, and with Brn3c -in a single monostratified subpopulation. Of interest, Brn3a and Ret are co-expressed in ON and OFF  RGCs 51 .…”