Characterization of dsRed2-positive cells in the doublecortin-dsRed2 transgenic adult rat retina
Doublecortin (DCX) is predominantly expressed in neuronal precursor cells and young immature neurons of the developing and adult brain, where it is involved in neuronal differentiation, migration and plasticity. Moreover, its expression pattern reflects neurogenesis, and transgenic DCX promoter-driven reporter models have been previously used to investigate adult neurogenesis. In this study, we characterize dsRed2 reporter protein-expressing cells in the adult retina of the transgenic DCX promoter-dsRed2 rat model, with the aim to identify cells with putative neurogenic activity. Additionally, we confirmed the expression of the dsRed2 protein in DCX-expressing cells in the adult hippocampal dentate gyrus. Adult DCX-dsRed2 rat retinas were analyzed by immunohistochemistry for expression of DCX, NF200, Brn3a, Sox2, NeuN, calbindin, calretinin, PKC-a, Otx2, ChAT, PSA-NCAM and the glial markers GFAP and CRALBP, followed by confocal laser-scanning microscopy. In addition, brain sections of transgenic rats were analyzed for dsRed2 expression and co-localization with DCX, NeuN, GFAP and Sox2 in the cortex and dentate gyrus. Endogenous DCX expression in the adult retina was confined to horizontal cells, and these cells co-expressed the DCX promoter-driven dsRed2 reporter protein. In addition, we encountered dsRed2 expression in various other cell types in the retina: retinal ganglion cells (RGCs), a subpopulation of amacrine cells, a minority of bipolar cells and in perivascular cells. Since also RGCs expressed dsRed2, the DCX-dsRed2 rat model might offer a useful tool to study RGCs in vivo under various conditions. Müller glial cells, which have previously been identified as cells with stem cell features and with neurogenic potential, did express neither endogenous DCX nor the dsRed2 reporter. However, and surprisingly, we identified a perivascular glial cell type expressing the dsRed2 reporter, enmeshed with the glia/stem cell marker GFAP and colocalizing with the neural stem cell marker Sox2. These findings suggest the so far undiscovered existence of perivascular associated cell with neural stem cell-like properties in the adult retina.
KeywordsDoublecortin Retina Retinal ganglion cells Perivascular cells Dentate gyrus Cortex
Inner nuclear layer
Inner plexiform layer
Ganglion cell layer
Retinal ganglion cells
The work was supported by Adele Rabensteiner Foundation, Fuchs-Foundation, Lotte Schwarz Endowment for Experimental Ophthalmology and Glaucoma Research, PMU-FFF (R-10/03/016-TRO) and FWF (FWF-P15729).
- Benninghoff DD (2004) Anatomie—makroskopische anatomie, histologie, embryologie, zellbiologie. Elsevier Urban Fisch 2:690–691Google Scholar
- Gomez-Climent MA, Guirado R, Castillo-Gomez E, Varea E, Gutierrez-Mecinas M, Gilabert-Juan J, Garcia-Mompo C, Vidueira S, Sanchez-Mataredona D, Hernandez S, Blasco-Ibanez JM, Crespo C, Rutishauser U, Schachner M, Nacher J (2010) The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) is expressed in a subpopulation of mature cortical interneurons characterized by reduced structural features and connectivity. Cereb Cortex 21:1028–1041PubMedCrossRefGoogle Scholar
- Nadal-Nicolas FM, Jimenez-Lopez M, Sobrado-Calvo P, Nieto-Lopez L, Canovas-Martinez I, Salinas-Navarro M, Vidal-Sanz M, Agudo M (2009) Brn3a as a marker of retinal ganglion cells: qualitative and quantitative time course studies in naive and optic nerve-injured retinas. Invest Ophthalmol Vis Sci 50:3860–3868PubMedCrossRefGoogle Scholar
- Nadal-Nicolas FM, Jimenez-Lopez M, Salinas-Navarro M, Sobrado-Calvo P, Alburquerque-Bejar JJ, Vidal-Sanz M, Agudo-Barriuso M (2012) Whole number, distribution and co-expression of brn3 transcription factors in retinal ganglion cells of adult albino and pigmented rats. PLoS ONE 7:e49830PubMedCentralPubMedCrossRefGoogle Scholar