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. 2013 Jun 28;8(6):e68084.
doi: 10.1371/journal.pone.0068084. Print 2013.

Retinal ganglion cells are resistant to photoreceptor loss in retinal degeneration

Bin Lin  1 , Edward Bo Peng
Affiliations

Retinal ganglion cells are resistant to photoreceptor loss in retinal degeneration

Bin Lin et al. PLoS One. .

Abstract

The rapid and massive degeneration of photoreceptors in retinal degeneration might have a dramatic negative effect on retinal circuits downstream of photoreceptors. However, the impact of photoreceptor loss on the morphology and function of retinal ganglion cells (RGCs) is not fully understood, precluding the rational design of therapeutic interventions that can reverse the progressive loss of retinal function. The present study investigated the morphological changes in several identified RGCs in the retinal degeneration rd1 mouse model of retinitis pigmentosa (RP), using a combination of viral transfection, microinjection of neurobiotin and confocal microscopy. Individual RGCs were visualized with a high degree of detail using an adeno-associated virus (AAV) vector carrying the gene for enhanced green fluorescent protein (EGFP), allowed for large-scale surveys of the morphology of RGCs over a wide age range. Interestingly, we found that the RGCs of nine different types we encountered were especially resistant to photoreceptor degeneration, and retained their fine dendritic geometry well beyond the complete death of photoreceptors. In addition, the RGC-specific markers revealed a remarkable degree of stability in both morphology and numbers of two identified types of RGCs for up to 18 months of age. Collectively, our data suggest that ganglion cells, the only output cells of the retina, are well preserved morphologically, indicating the ganglion cell population might be an attractive target for treating vision loss.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Transduction of retinal ganglion cells (RGCs) in rd1 mice following intravitreal administration of an adeno-associated virus (AAV) vector carrying the gene for enhanced green fluorescent protein (EGFP).
Representative retinal flat mount shows extensive GFP expression throughout the whole retina. Some GFP expressing cells have the size and dendritic morphology of RGCs and possess an axon leading from the cells to the optic disc (arrows), indicative of RGCs. The entire dendritic tree structure of some RGCs is clearly visualized by GFP expression (inset). Scale bars, 1 mm (100 µm in inset).
Figure 2
Figure 2. Determining the dendritic stratification level of RGCs in the IPL.
A, One representative image of AAV-GFP transduced RGCs in a cross section of rd1 retinas. In this illustration, the RGC has a big soma (arrow) and a broad dendritic tree (arrowheads). B, To define the stratification level of RGC dendrites in the IPL, we stained cell nuclei with diamidinophenylindole (DAPI). The INL and GCL delineate the proximal (0%) and distal (100%) boundaries of the IPL, respectively. C, Merged image shows that the dendrite of the RGC are centered at 25% of the IPL. D–F, One representative image of AAV-GFP transduced RGCs in a cross section of WT mouse retinas was shown as comparison. The transfection in WT was similar to what we observed in rd1 mice. G–I, To distinguish RGCs from diaplaced amacrine cells, AAV-GFP transduced retinas were co-labeled with an antiserum against Thy-1, a marker for all RGCs. Single image section was taken from the ganglion cell layer with focus on cell bodies, and the axon of one AAV-GFP transduced cell was out of focus (arrow). The transduced cell with an axon colocalized with Thy-1 (solid arrowhead), while another transduced cell without an axon did not colocalize with Thy-1 (open arrowhead). INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer. Scale bars, 20 µm in A–F, and 10 µm in G–I.
Figure 3
Figure 3. A large-scale survey of RGCs in rd1 retinas of 18 month-old.
Individual RGCs are visualized by GFP expression. Representations of nine types of RGCs are shown together with their dendritic diameters and stratification in the IPL. Numbers in parentheses correspond to the cell types distinguished by Sun et al. (2002). Insets show the dendritic stratification of RGCs in the IPL. In the inset, green circle shows the location of soma, and green line indicates dendrites. The dendrites of Off and On RGCs stratified in the proximal (0–40%) and distal (40–100%) parts of the IPL, respectively. Note that this representation shows the depth of the processes only and does not attempt to show their spread. Arrows indicate axons of individual representative RGCs. INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer. Scale bars, 50 µm.
Figure 4
Figure 4. Representative A2 RGCs classified using nomenclature of Sun et al. (2002), from both WT and rd1 mice of different ages.
A–F, A2 RGCs were injected with neurobiotin, stained with fluorochrome-conjugated streptavidin, and reconstructed from mosaics of confocal Z-series. Arrows indicate axonal processes emerging from the somata of the A2 RGCs. Arrowhead in B indicates an axon of another injected RGC passing through this A2 RGC. G: Histogram of mean dendritic field diameters of A2 RGCs. There was no significant difference in dendritic-field sizes of A2 RGCs between WT and rd1 retinas (p>0.05, one-way ANOVA analysis). H: Histogram of mean soma diameters of A2 RGCs. There was no significant difference in soma sizes between WT and rd1 retinas (p>0.05, one-way ANOVA analysis). Scale bars, 50 µm.
Figure 5
Figure 5. SMI-32 immunostaining in the rd1 retina and the cell types it reveals.
A–C, Antibody to SMI32 was reacted against flat mounted retinas of rd1 mice of different ages, developed using DAB-immunohistochemistry. Arrows point to α ganglion cells. A’–C’, Highly magnified image from the boxed regions in A–C. Scale bars, 50 µm in A–C, and 25 µm in A’–C’.
Figure 6
Figure 6. Somatic and dendritic-field sizes of SMI-32 positive α RGCs and their density distribution in the rd1 retina.
A: Histogram of mean dendritic field diameters of α ganglion cells stained by SMI-32. N indicates the number of α RGCs studied. B: Histogram of mean soma diameters of α ganglion cells stained by SMI-32. There was no significant difference in either dendritic-field sizes or soma sizes of α ganglion cells between WT and rd1 retinas (p>0.05, one-way ANOVA analysis). C, The diagram illustrates six sampling areas, regularly spaced along the dorsal-ventral axis of retinal whole-mounts, were surveyed for all cell counting. ONH, optic nerve head. D, The graphs show the density distribution of SMI-32 positive RGCs from both WT and rd1 mouse retinas at two different ages.
Figure 7
Figure 7. Intrinsically photosensitive RGCs (ipRGC) in the mouse retina.
A–D, An antibody to melanopsin was reacted against flat mounted retinas and developed using DAB-immunohistochemistry. Scale bar, 50 µm. E–F: Histograms show the distribution of the dendritic field diameters of M1 cells in WT and rd1 retinas at 3 month-old (E) and 18 momth-old (F). G–H: Histograms show the distribution of the soma diameters of M1 cells in WT and rd1 retinas at 3 month-old (G) and 18 momth-old (H). I, The graph shows the average densities of M1 cells across the dorso-ventral axe from both WT and rd1 mouse retinas at two different ages.
Figure 8
Figure 8. RGC Populations in rd1 mouse retinas.
A–B, RGCs were revealed by using an antiserum against Thy-1, a marker for all RGCs in the mouse retina. Two representative images were taken from rd1 retinas at the age of 3 months (A) and 18 months (B). Thy-1 is a surface glycoprotein uniquely expressed in RGC’s membrane (Arrows). Scale bar, 10 µm. C, Quantification of Thy-1 positive cells in the ganglion cell layer of both WT and rd1 retinas at two different ages. Values are mean ± SD, with n indicating the number of retinas counted.
Figure 9
Figure 9. Cell populations in the ganglion cell layer of rd1 mouse retinas.
A–B, Images of DAPI labeled cells in the ganglion cell layer were taken from the retinal regions located 1 mm superior to the center of the optic nerve head at two different ages. Scale bar, 10 µm. C, Quantification of DAPI labeled cells in the ganglion cell layer of rd1 mice at three different ages. Values are mean ± SD, with n indicating the number of retinas counted.
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References

    1. Bramall AN, Wright AF, Jacobson SG, McInnes RR (2010) The genomic, biochemical, and cellular responses of the retina in inherited photoreceptor degenerations and prospects for the treatment of these disorders. Ann Rev Neurosci 33: 441–472. - PubMed
    1. Wright AF, Chakarova CF, Abd El-Aziz MM, Bhattacharya SS (2010) Photoreceptor degeneration: genetic and mechanistic dissection of a complex trait. Nat Rev Genet 11: 273–284. - PubMed
    1. Blanks JC, Adinolfi AM, Lolley RN (1974) Photoreceptor degeneration and synaptgenesis in retinal-degenerative (rd) mice. J Comp Neurol 156: 81–94. - PubMed
    1. Bowes C, Li T, Danciger M, Baxter LC, Applebury ML, et al. (1990) Retinal degeneration in the rd mouse is caused by a defect in the beta subunit of rod cGMP-phosphodiesterase. Nature 347: 677–680. - PubMed
    1. Farber D, B., Lolley RN (1974) Cyclic guanosine monophosphate: elevation in degenerating photoreceptor cells of the C3H mouse retina. Science 186: 449–451. - PubMed

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This work was supported by The University of Hong Kong Seed Funding Program for Basic Research and General Research Fund from the Hong Kong Research Grants Council (772810). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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