Immunocytochemical analysis of misplaced rhodopsin-positive cells in the developing rodent retina

Abstract

During the first postnatal weeks of the developing rodent retina, rhodopsin can be detected in a number of neuron-like cells in the inner retina. In the present study, we aim to characterize the morphology, number and staining characteristics of this peculiar population. Misplaced rhodopsin-positive cells (MRCs) were analyzed on retinas of four rodent species, labeled with various rhodopsin-specific antibodies. To investigate their possible relation with non-photoreceptor cells, sections were double-stained against distinct retinal cell types and proteins of the phototransduction cascade. The possibility of synapse formation and apoptosis were also investigated. In all species studied, misplaced cells comprised a few percent of all rhodopsin-positive elements. This ratio declined from the end of the second week and MRCs disappeared nearly completely from the retina by P24. MRCs resembled resident neurons of the inner retina, while outer segment-like processes were seen only rarely. MRCs expressed no other photopigment types and showed no colocalization with any of the bipolar, horizontal, amacrine and ganglion cell markers used. While all MRCs colabeled for arrestin and recoverin, other proteins of the phototransduction cascade were only detectable in a minority of the population. Only a few MRCs were shown to form synaptic-like endings. Our results showed that, during development, some rhodopsin-expressing cells are displaced to the inner retinal layers. Although most MRCs lack morphological features of photoreceptors, they contain some but not all, elements of the phototransduction cascade, indicating that they are most probably misplaced rods that failed to complete differentiation and integrate into the photoreceptor mosaic.

Melanopsin Retinal Ganglion Cells Regulate Cone Photoreceptor Lamination in the Mouse Retina

“…A small sub-population of cones displaced to the inner retina has been previously reported in the rat and human retina (Semo et al, 2007), consistent with the findings reported here in mice. Similarly, a small population of displaced rod photoreceptors has been observed in the rat retina, but these cells appear to be eliminated by adulthood (Gunhan et al, 2003; Szabo€ ´ et al, 2014). In contrast, our data indicate that at least some DCs remain in the adult mouse retina and the continued presence of ipRGCs is required to restrict their numbers, as evidenced by the elevated number of DCs in adult Opn4 DTA/DTA retinas compared to controls.…”

Study of retinal neurodegeneration and maculopathy in diabetic Meriones shawi: A particular animal model with human‐like macula

“…The antibody against GFAP was raised using GFAP from pig spinal cord as immunogen, and shown by the supplier to reacts specifically with GFAP in immunoblotting assays. Its reactivity in the retina has also been established in the rat (Enzsoly et al, ; Lieth et al, ) and in other rodent species (Szabo, Szabo, Enzsoly, Szel, & Lukats, ). The staining pattern in M.sh was identical, mostly restricted to astrocytes and the end feet of Müller cells in control specimens, while showing a more or less prominent upregulation in Müller cells in hyperglycemic specimens.…”

“…Amino acids 651–672 at the C‐terminus of PKC‐α of human origin was used to produce the antibody applied in the study. The staining of rod bipolar cells (and some amacrine cells) in the rodent retina is well documented (Enzsoly et al, ; Greferath, Grunert, & Wassle, ; Szabo, Szabo, Enzsoly, Szel, & Lukats, ) and staining in M.sh . gave practically identical results.…”

“…Recombinant rat calretinin was used to raise the calretinin antibody in the study. Calretinin is known to be present in several retinal cell types of practically all mammalian species tested, being present in the inner nuclear layer (INL) and GCL (Enzsoly et al, ; Hwang et al, ; Szabo, Szabo, Enzsoly, Szel, & Lukats, ). Identical pattern was observed in M.sh .…”

Immunocytochemical Profiling of Cultured Mouse Primary Retinal Cells

“…32 Rhodopsin, a photopigment of the G-protein-coupled protein superfamily, is present only in rod PRs, thus considered a marker for rod PRs. 33 To identify cone PRs, we use cone arrestin. Arrestins are a superfamily of regulatory proteins involved in G-protein-coupled receptor (GPCR) desensitization, internalization, and GPCR-mediated activation of mitogen-activated protein kinase pathways.…”