This study was supported by grants from the National Natural Science Foundation of China (No. 81960180), the Zinke heritage foundation, and the Charlotte and Tistou Kerstan Foundation, Yunnan Eye Disease Clinical Medical Center (ZX2019-02-01). We thank Prof. Longbao Lv (Institute of Zoology, Chinese Academy of Sciences, Kunming, China) for sharing the monkey eyeballs used in this study.

The animal study was reviewed and approved by the Ethics Review Committee of Institute of Zoology, Chinese Academy of Sciences (IACUC-PE-2022-06-002), and animal ethics review and animal protocol of Yunnan University (YNU20220149).
1. Preparation of retinal explants
<ol>
	<li>Obtain primate eyeballs from wild-type macaques, aged 1 to 3 years old, store in tissue storage solution, and transport on ice within 3 h of enucleation after the monkeys were sacrificed or after natura...

<ol>
	<li>O'Neal, T. B., Luther, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> StatPearls. , (2022).</li><li>Power, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+mechanisms+of+hereditary+photoreceptor+degeneration+-+Focus+on+cGMP.">Cellular mechanisms of hereditary photoreceptor degeneration - Focus on cGMP.</a> Progress in Retinal and Eye Research. 74, 100772 (2020).</li><li>Paquet-Durand, F., Hauck, S. M., van Veen, T., Ueffing, M., Ekstr&#246;m, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PKG+activity+causes+photoreceptor+cell+death+in+two+retinitis+pigmentosa+models.">PKG activity causes photoreceptor cell death in two retinitis pigmentosa models.</a> Journal of Neurochemistry. 108 (3), 796-810 (2009).</li><li>Tolone, A., Belhadj, S., Rentsch, A., Schwede, F., Paquet-Durand, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cGMP+pathway+and+inherited+photoreceptor+degeneration:+Targets,+compounds,+and+biomarkers.">The cGMP pathway and inherited photoreceptor degeneration: Targets, compounds, and biomarkers.</a> Genes (Basel). 10 (6), 453 (2019).</li><li>Arango-Gonzalez, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+a+common+non-apoptotic+cell+death+mechanism+in+hereditary+retinal+degeneration.">Identification of a common non-apoptotic cell death mechanism in hereditary retinal degeneration.</a> PLoS One. 9 (11), 112142 (2014).</li><li>Mencl, S., Trifunovi&#263;, D., Zrenner, E., Paquet-Durand, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PKG-dependent+cell+death+in+661W+cone+photoreceptor-like+cell+cultures+(experimental+study).">PKG-dependent cell death in 661W cone photoreceptor-like cell cultures (experimental study).</a> Advances in Experimental Medicine and Biology. 1074, 511-517 (2018).</li><li>Power, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+spatiotemporal+mapping+reveals+divergent+cell+death+pathways+in+three+mouse+models+of+hereditary+retinal+degeneration.">Systematic spatiotemporal mapping reveals divergent cell death pathways in three mouse models of hereditary retinal degeneration.</a> Journal of Comparative Neurology. 528 (7), 1113-1139 (2020).</li><li>Sancho-Pelluz, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excessive+HDAC+activation+is+critical+for+neurodegeneration+in+the+rd1+mouse.">Excessive HDAC activation is critical for neurodegeneration in the rd1 mouse.</a> Cell Death &amp; Disease. 1 (2), 24 (2010).</li><li>Kulkarni, M., Trifunovi&#263;, D., Schubert, T., Euler, T., Paquet-Durand, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+dynamics+change+in+degenerating+cone+photoreceptors.">Calcium dynamics change in degenerating cone photoreceptors.</a> Human Molecular Genetics. 25 (17), 3729-3740 (2016).</li><li>Trifunovi&#263;, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=cGMP-dependent+cone+photoreceptor+degeneration+in+the+cpfl1+mouse+retina.">cGMP-dependent cone photoreceptor degeneration in the cpfl1 mouse retina.</a> Journal of Comparative Neurology. 518 (17), 3604-3617 (2010).</li><li>Samardzija, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HDAC+inhibition+ameliorates+cone+survival+in+retinitis+pigmentosa+mice.">HDAC inhibition ameliorates cone survival in retinitis pigmentosa mice.</a> Cell Death &amp; Differentiation. 28 (4), 1317-1332 (2021).</li><li>Sch&#246;n, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+therapy+successfully+delays+degeneration+in+a+mouse+model+of+PDE6A-linked+Retinitis+Pigmentosa+(RP43).">Gene therapy successfully delays degeneration in a mouse model of PDE6A-linked Retinitis Pigmentosa (RP43).</a> Human Gene Therapy. 28 (12), 1180-1188 (2017).</li><li>McGregor, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optogenetic+therapy+restores+retinal+activity+in+primate+for+at+least+a+year+following+photoreceptor+ablation.">Optogenetic therapy restores retinal activity in primate for at least a year following photoreceptor ablation.</a> Molecular Therapy. 30 (3), 1315-1328 (2022).</li><li>Lingam, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=cGMP-grade+human+iPSC-derived+retinal+photoreceptor+precursor+cells+rescue+cone+photoreceptor+damage+in+non-human+primates.">cGMP-grade human iPSC-derived retinal photoreceptor precursor cells rescue cone photoreceptor damage in non-human primates.</a> Stem Cell Research &amp; Therapy. 12 (1), 464 (2021).</li><li>Das, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+cGMP-signalling+and+calcium-signalling+in+photoreceptor+cell+death:+perspectives+for+therapy+development.">The role of cGMP-signalling and calcium-signalling in photoreceptor cell death: perspectives for therapy development.</a> Pflugers Archiv. 473 (9), 1411-1421 (2021).</li><li>Hoon, M., Okawa, H., Della Santina, L., Wong, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+architecture+of+the+retina:+Development+and+disease.">Functional architecture of the retina: Development and disease.</a> Progress in Retinal and Eye Research. 42, 44-84 (2014).</li><li>Schnichels, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retina+in+a+dish:+Cell+cultures,+retinal+explants+and+animal+models+for+common+diseases+of+the+retina.">Retina in a dish: Cell cultures, retinal explants and animal models for common diseases of the retina.</a> Progress in Retinal and Eye Research. 81, 100880 (2021).</li><li>Maryam, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+organization+of+human+cGMP+specific+Phosphodiesterase+6+(PDE6):+Structural+implications+of+somatic+mutations+in+cancer+and+retinitis+pigmentosa.">The molecular organization of human cGMP specific Phosphodiesterase 6 (PDE6): Structural implications of somatic mutations in cancer and retinitis pigmentosa.</a> Computational and Structural Biotechnology Journal. 17, 378-389 (2019).</li><li>Huang, L., Kutluer, M., Adani, E., Comitato, A., Marigo, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+in+vitro+cellular+model+for+molecular+studies+of+retinitis+pigmentosa.">New in vitro cellular model for molecular studies of retinitis pigmentosa.</a> International Journal of Molecular Sciences. 22 (12), 6440 (2021).</li><li>Zhou, J., Rasmussen, M., Ekstr&#246;m, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=cGMP-PKG+dependent+transcriptome+in+normal+and+degenerating+retinas:+Novel+insights+into+the+retinitis+pigmentosa+pathology.">cGMP-PKG dependent transcriptome in normal and degenerating retinas: Novel insights into the retinitis pigmentosa pathology.</a> Experimental Eye Research. 212, 108752 (2021).</li></ol>

Visual phototransduction refers to the biological process by which light signals are converted to electrical signals by photoreceptor cells within the retina of the eye. Photoreceptor cells are polarized neurons capable of phototransduction, and there are two different types of photoreceptors termed rods and cones after the shapes of their outer segments. Rods are responsible for the scotopic vision and cones are responsible for photopic and high acuity vision. Hereditary RD relates to neurodegenerative diseases characte...

Hereditary retinal degeneration (RD) is characterized by progressive photoreceptor cell death and is caused by mutations in a wide variety of pathogenic genes1. The end result of RD is vision loss and in the vast majority of cases the disease remains untreatable to this day. Therefore, it is important to study the cellular mechanisms leading to photoreceptor death using models that faithfully represent the human disease condition. Here, primate-based models are of particular interest due to their closeness to humans. Notably, such models may advance the development of appropriate therapeutic interventions that can halt or delay photoreceptor cell death.
Previous research on the mechanisms of cell death in RD has demonstrated that the decrease or loss of phosphodiesterase 6 (PDE6) activity caused by RD-triggering gene mutations leads to reduced hydrolysis of cyclic guanosine monophosphate (cGMP)2,3. cGMP is a specific agonist of the cyclic nucleotide-gated ion channels (CNGCs) in the rod outer segments (ROSs) and is also a key molecule responsible for the conversion of light signals into electrical signals in vertebrate photoreceptor cells4. Reduced cGMP hydrolysis causes the accumulation of cGMP in ROSs, leading to the opening of CNGCs 5. Consequently, the phototransduction pathways are activated, resulting in an increase in cation concentrations in photoreceptor cells. This process imposes a metabolic burden on photoreceptors, which when overactivated, for instance, by mutations in PDE6, may cause cell death.
Many studies have shown that a significant overaccumulation of cGMP in photoreceptors of mouse models with different RD gene mutations may cause the activation of cGMP-dependent protein kinase (PKG)3,6. This leads to a substantial increase in dying, TUNEL-positive cells and a gradual thinning of the photoreceptor cell layer. Previous studies suggest that PKG overactivation caused by elevated cGMP levels is a necessary and sufficient condition for the induction of photoreceptor cell death2,5. Studies on different mouse models of RD have also shown that PKG activation induced by elevated cGMP levels in photoreceptors, leads to overactivation of downstream effectors such as poly-ADP-ribose polymerase 1 (PARP1), histone deacetylase (HDAC), and calpain2,7,8,9. This implies causal associations between these different target proteins and photoreceptor cell death.
However, previous research on the pathology, toxicopharmacology, and therapy of RD was mainly based on mouse models for RD10,11,12. Nevertheless, immense difficulties remain in the clinical translation of these results. This is owing to the considerable genetic and physiological differences between mice and humans, especially with respect to the retinal structure. In contrast, non-human primates (NHPs) also share a high degree of similarity with humans with respect to genetic characteristics, physiological patterns, and environmental factor regulation. For example, optogenetic therapy was investigated as a means to restore retinal activity in an NHP model13. Lingam and colleagues demonstrated that good manufacturing practice-grade human-induced pluripotent stem cell-derived retinal photoreceptor precursor cells may rescue cone photoreceptor damage in NHP14. Therefore, NHP models are important for the exploration of RD pathogenesis and the development of effective treatment methods. In particular, NHP models of RD, exhibiting pathogenic mechanisms similar to those in humans, could play a critical role in studies on the development and in vivo toxicopharmacology analysis of new drugs.
In view of the long life-cycle, high level of technical difficulties, and high cost involved in establishing in vivo primate models, we established an in vitro non-human primate (NHP) model using cultures of explanted macaque retina. First, wild-type macaques aged 1-3 years were selected for in vitro culture of retinal explants, which included the retina-RPE-choroid complex. Explants were then treated with different concentrations of the PDE6 inhibitor zaprinast (100 &#181;M, 200 &#181;M, and 400 &#181;M) to induce the cGMP-PKG signaling pathway. Photoreceptor cell death was quantified and analyzed using the TUNEL assay, and cGMP accumulation in explants was verified via immunofluorescence. Given the high degree of similarity with respect to cell distribution and morphology, retinal layer thickness, and other physiological characteristics of the retina between monkeys and humans, the establishment of the cGMP-PKG signaling pathway in the in vitro retinal model may facilitate future research on the pathogenesis of RD as well as studies into the development and toxicopharmacology of new drugs for RD treatment.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bovine Serum Albumin (BSA)</td>
			<td>Sigma</td>
			<td>B2064</td>
			<td>Blocking solution</td>
		</tr>
		<tr>
			<td>Corticosterone</td>
			<td>Sigma</td>
			<td>C2505</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>DL-tocopherol</td>
			<td>Sigma</td>
			<td>T1539</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Donkey anti sheep, Alxea Fluor 488</td>
			<td>Life technologies corporation</td>
			<td>A11015</td>
			<td>Secondary antibody of cGMP</td>
		</tr>
		<tr>
			<td>Ethanol-acetic acid solution</td>
			<td>Shyuanye</td>
			<td>R20492</td>
			<td>Fixing liquid</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Gemini</td>
			<td>900-108</td>
			<td>Blocking solution</td>
		</tr>
		<tr>
			<td>Fluorescence microscope</td>
			<td>Carl Zeiss</td>
			<td>Axio Imager.M2</td>
			<td>Immunofluorescence imaging</td>
		</tr>
		<tr>
			<td>Glutamine</td>
			<td>Sigma</td>
			<td>G8540</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Glutathione</td>
			<td>Sigma</td>
			<td>G6013</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>In Situ Cell Death Detection Kit, TMR red</td>
			<td>Roche</td>
			<td>12156792910</td>
			<td>TUNEL assay</td>
		</tr>
		<tr>
			<td>Insulin</td>
			<td>Sigma</td>
			<td>16634</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>L-cysteine HCl</td>
			<td>Sigma</td>
			<td>C7477</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Linoleic acid</td>
			<td>Sigma</td>
			<td>L1012</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>MACS Tissue Storage Solution</td>
			<td>Miltenyi</td>
			<td>130-100-008</td>
			<td>Optimized storage of fresh organ and tissue samples</td>
		</tr>
		<tr>
			<td>Normal Donkey Serum</td>
			<td>Solarbio</td>
			<td>SL050</td>
			<td>Blocking solution</td>
		</tr>
		<tr>
			<td>Paraformaldehyde(PFA)</td>
			<td>Biosharp</td>
			<td>BL539A</td>
			<td>Fixing agent</td>
		</tr>
		<tr>
			<td>PEN. / STREP. 100&#215;</td>
			<td>Millipore</td>
			<td>TMS-AB2-C</td>
			<td>Penicillin / Streptomycin antibiotics</td>
		</tr>
		<tr>
			<td>Phosphate buffer saline(PBS)</td>
			<td>Solarbio</td>
			<td>P1010</td>
			<td>Buffer solution</td>
		</tr>
		<tr>
			<td>Povidone-iodine</td>
			<td>Shanghailikang</td>
			<td>310411</td>
			<td>Disinfector agent</td>
		</tr>
		<tr>
			<td>Progesterone</td>
			<td>Sigma</td>
			<td>P8783</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Millpore</td>
			<td>539480</td>
			<td>Break down protein</td>
		</tr>
		<tr>
			<td>R16 medium</td>
			<td>Life technologies corporation</td>
			<td>074-90743A</td>
			<td>Basic medium</td>
		</tr>
		<tr>
			<td>Retinol</td>
			<td>Sigma</td>
			<td>R7632</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Retinyl acetate</td>
			<td>Sigma</td>
			<td>R7882</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Sheep anti-cGMP</td>
			<td>Jan de Vente, Maastricht University, the Netherlands</td>
			<td></td>
			<td>Primary antibody of cGMP</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>GHTECH</td>
			<td>57-50-1</td>
			<td>Dehydrating agent</td>
		</tr>
		<tr>
			<td>T3</td>
			<td>Sigma</td>
			<td>T6397</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Tissue-Tek medium (O.C.T. Compound)</td>
			<td>SAKURA</td>
			<td>4583</td>
			<td>Embedding medium</td>
		</tr>
		<tr>
			<td>Tocopheryl acetate</td>
			<td>Sigma</td>
			<td>T1157</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Transferrin</td>
			<td>Sigma</td>
			<td>T1283</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Transwell</td>
			<td>Corning Incorporated</td>
			<td>3412</td>
			<td>Cell / tissue culture</td>
		</tr>
		<tr>
			<td>Tris-buffer (TBS)</td>
			<td>Solarbio</td>
			<td>T1080</td>
			<td>Blocking buffer</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Solarbio</td>
			<td>9002-93-1</td>
			<td>Surface active agent</td>
		</tr>
		<tr>
			<td>VECTASHIELD Medium with DAPI</td>
			<td>Vector</td>
			<td>H-1200</td>
			<td>Mounting medium</td>
		</tr>
		<tr>
			<td>Vitamin B1</td>
			<td>Sigma</td>
			<td>T1270</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Vitamin B12</td>
			<td>Sigma</td>
			<td>V6629</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Vitamin C</td>
			<td>Sigma</td>
			<td>A4034</td>
			<td>Supplements of Complete Medium</td>
		</tr>
		<tr>
			<td>Zaprinast</td>
			<td>Sigma</td>
			<td>Z0878</td>
			<td>PDE6 inhibitor</td>
		</tr>
		<tr>
			<td>Zeiss Imager M2 Microscope</td>
			<td>&#160;Zeiss, Oberkochen,Germany</td>
			<td></td>
			<td>upright microscope</td>
		</tr>
		<tr>
			<td>LSM 900 Airyscan</td>
			<td></td>
			<td></td>
			<td>high resolution laser scanning microscope</td>
		</tr>
		<tr>
			<td>Zeiss Axiocam</td>
			<td>&#160;Zeiss, Oberkochen,Germany</td>
			<td></td>
			<td>digital camera</td>
		</tr>
		<tr>
			<td>Zeiss Axiovision4.7</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adobe</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Illustrator CC 2021 (Adobe Systems Incorporated, San Jose, CA)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Primate eyeballs from wildtype macaque</td>
			<td>KUNMING INSTITUTE OF ZOOLOGY</td>
			<td>SYXK (<img alt="Equation 1" src="/files/ftp_upload/64178/64178eq01.jpg" style="margin: auto;" />) K2017 -0008</td>
			<td></td>
		</tr>
		<tr>
			<td>Super Pap Pen Pen (Liquid Blocker, Diado, 0010, Japan</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>TUNEL kit solution (REF12156792910, Roche,Germany),</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

organotypic retinal explant cultures from macaque monkey

Hereditary retinal degeneration (RD) is characterized by progressive photoreceptor cell death. Overactivation of the cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG) pathway in photoreceptor cells causes photoreceptor cell death, especially in models harboring phosphodiesterase 6b (PDE6b) mutations. Previous studies on RD have used mainly murine models such as rd1 or rd10 mice. Given the genetic and physiological differences between mice and humans, it is important to understand to which extent the retinas of primates and rodents are comparable. Macaques share a high level of genetic similarity with humans. Therefore, wild-type macaques (aged 1-3 years) were selected for the in vitro culture of retinal explants that included the retina-retinal pigment epithelium (RPE)-choroid complex. These explants were treated with different concentrations of the PDE6 inhibitor zaprinast to induce the cGMP-PKG signaling pathway and simulate RD pathogenesis. cGMP accumulation and cell death in primate retinal explants were subsequently verified using immunofluorescence and the TUNEL assay. The primate retinal model established in this study may serve for relevant and effective studies into the mechanisms of cGMP-PKG-dependent RD, as well as for the development of future treatment approaches.

In this study, Macaque monkey retinal explant culture was performed using explants containing the retina-RPE-choroid complex (Figure 1, Supplementary Figure S1). Compared with the in vitro culture of retinal cells using the retina without the attached RPE and choroid, our explant culture facilitates better cell survival and accordingly, prolongs the survival of photoreceptor cells.
We used different concentrations of the PDE6 inhibitor za...

Watch this Scientific Journal Video about Organotypic Retinal Explant Cultures from Macaque Monkey at JoVE.com

Organotypic Retinal Explant Cultures from Macaque Monkey

Retinal explants obtained from wild-type macaques were cultured in vitro. Retinal degeneration and the cGMP-PKG signaling pathway was induced using the PDE6 inhibitor zaprinast. cGMP accumulation in the explants at different zaprinast concentrations was verified using immunofluorescence.

Hereditary retinal degeneration (RD) is characterized by progressive photoreceptor cell death. Overactivation of the cyclic guanosine monophosphate ...

The primate retinal model established in this study we offering the investigation of the comprehensive mechanism and the therapeutic development of cGMP-PKG dependent retinal deterioration. This individual nonhuman primate model reserves retinal tissue confirmation and intercellular interactions which enables better simulation of in vivo conditions. It also reduces the animal use and it shortens the experimental duration.Providing a control experimental approach for investigating retinal development or degeneration. Begin the preparation of the retinal explants by washing the eyeballs isolated from wild type macaques with 10 milliliters of 5%povidone iodine for 30 seconds. To avoid bacterial contamination, dip the eyeballs into a 5%penicillin streptomycin PBS solution for one minute before incubation in 10 milliliters of R16 medium for five minutes.Then immerse the eyeballs in 10 milliliters of protein Ace-K solution preheated at 37 degrees Celsius and incubated for two minutes. Perform next incubation in 10 milliliters of one to one R16 plus fetal bovine serum solution for five minutes. Give a final wash in 10 milliliters of fresh R16.Once done, separate the sclera, cornea, iris, lens and vitreous body. Then cut the retina from four sides with tweezers and scissors. Next, use a four milliliter tree fine blade to cut the retinal explant at a 1.5 millimeter from the nasal side, four millimeter from the temporal side and a two millimeter from the superior and inferior sides of the optic nerve head.Then using a six millimeter tree fine blade cut the central side of the retinal explant containing the optic disc and macula. Using a wide pipet, pull the retina explant containing the retina and choroid and place it in the middle of the insert with the photoreceptor side up. Fully submerge the retina in one milliliter of the complete medium on the plate below the membrane.Culture the retinal explants and place them in a 37 degree Celsius incubator with humidified 5%carbon dioxide. Give the appropriate drug concentration treatment to explants for four days. Use at least three explants per treatment condition and use the explants without the drug as a positive control.For fixing and cryo-sectioning, treat the retinal explants with one milliliter of paraform aldehyde for 45 minutes. After a brief rinsing with one milliliter of PBS serially incubate the explants in 10%sucrose for 10 minutes, 20%sucrose for 20 minutes, and 30%sucrose for 30 minutes. Cut the retinal explants uniformly with four quadrants in the periphery and six millimeters at the center.Then transfer the retinal explants into a tin box of about 1.5 by 1.5 by 1.5 centimeters with an optimal cutting temperature compound embedding medium covering the explant. Immediately, freeze the tissue sections in liquid nitrogen and place them in a 20 degrees refrigerator for storage. Next, trim the agar into a small block containing the tissue sample.Section the blocks into 10 micrometer blocks and place the sections on adhesion microscope slides using a soft brush. Then dry the sections for 45 minutes at 40 degrees Celsius and store them at minus 80 degrees Celsius until use. For cyclic guanosine monophosphate or cGMP staining, draw a hydrophobic ring around the dried retinal sections with a liquid blocker pen and cover the samples.Immerse the slides in 200 microliters of 0.3%PBS and Triton-X100 or PBST for 10 minutes followed by a one hour treatment in 200 microliters of blocking solution at room temperature. Next, incubate the sample slide overnight with the 200 microliters of primary antibody prepared in the blocking solution at four degrees Celsius and rinse it thrice with PBS for 10 minutes. Incubate the slide in 200 microliters of secondary antibody for one hour at room temperature.After three washes of PBS for 10 minutes cover the samples with an antifade mounting medium containing DAPI and store at four degrees Celsius for at least 30 minutes before imaging. Dry the slide at room temperature for 15 minutes and draw a water repellent barrier ring around the retinal tissue specimen with a liquid blocker pen. After incubation with 40 milliliters of PBS for 15 minutes treat the sections with 42 milliliters of 0.05 molar tris-buffer or TBS at 37 degrees Celsius.Aspirate the TBS, incubate the samples with six microliters of proteinase K for five minutes and wash slides thrice with PBS for five minutes each. Expose the slides to 40 milliliters of ethanol acetic acid solution in the chaplin. Cover it with a transparent sheet and incubate at minus 20 degrees Celsius for five minutes.Wash the slides thrice with TBS for five minutes each time. Expose the slides to 200 to 300 microliters of blocking solution or 1%BSA and incubate them in a humidity chamber for one hour. At approximately 130 microliters of TMR red solution per slide and after one hour, give two washes of 200 microliters of PBS for five minutes each.Place cover slides containing one to two drops of antifade mounting medium with DAPI over the samples and incubate the slides at four degrees Celsius for at least 30 minutes before imaging. After sequential staining with tunnel and cGMP proceed for light and fluorescence microscopy by adjusting the camera parameters. Capture the images of four fields from each section using the software with a digital camera at 20x magnification.Obtain representative pictures from the central areas of the retina using DAPI, EGFP and TMR with z-stack scanning and an interval of one micrometer and optional at 1.251 micrometers. In the retinal explants treated with different concentrations of the PDE6 inhibitors Zaprinast the number of tunnel and cGMP positive cells were strongly increased in the outer nuclear layer as compared with the control group. The high proportion of tunnel positive cells suggested that the increase in cGMP activity may enhance the pre nest induced retinal cell degeneration and cGMP accumulation plays a role in photoreceptor degeneration.Explant preparation must be carried out as soon as possible. Op animal scatter fives and any accumulation because it improves cell survival and enhance the status of fiber of bulk stack series. To a greatest extent visible the vitreous should be cleaned with steroids.Avoid contacting the retinal nerve fiber layers when transferring retinal explants to prevent mechanical cell injury. Please take note, to issue a smooth transfer of retinal explants to culture inserts the pet can be pre-soaked in something to keep it moist before transferring retinal tissues. Additionally, the entire process must be carried out in the steroid atmosphere to avoid contamination during in the process.

organotypic-retinal-explant-cultures-from-macaque-monkey

Research

JoVE Journal

Neuroscience

1.1K ビュー.  Yunnan University. 本研究で確立した霊長類網膜モデルを用いて、cGMP-PKG依存性網膜劣化の包括的なメカニズムの解明と治療法開発を提供します。この個々の非ヒト霊長類モデルは、網膜組織の確認と細胞間相互作用を予約し、in vivo状態のより良いシミュレーションを可能にします。また、動物の使用を減らし、実験期間を短縮します。網膜の発達または変性を調査するための制御実?...

ビデオ: Organotypic Retinal Explant Cultures from Macaque Monkey

Retinal explants obtained from wild-type macaques were cultured in vitro. Retinal degeneration and the cGMP-PKG signaling pathway was induced using the PDE6 inhibitor zaprinast. cGMP accumulation in the explants at different zaprinast concentrations was verified using...

neural explant cultures from xenopus laevis

Neural Explant Cultures from Xenopus laevis

Culturing neural explants from dissected Xenopus laevis embryos that express fluorescent fusion proteins allows for imaging of growth cone cytoskeletal...

Neural Explant Cultures from Xenopus laevis

a pressure injection system for investigating the neuropharmacology of information processing in awake behaving macaque monkey cortex

A Pressure Injection System for Investigating the Neuropharmacology of Information Processing in Awake Behaving Macaque Monkey Cortex

Here, we show the pressure injection of neuropharmacological substances during single-cell recording in an awake, behaving macaque monkey. This procedure allows pharmacological manipulation in the direct vicinity of a cortical recording site.

in vivo-like organotypic murine retinal wholemount culture

In vivo-like Organotypic Murine Retinal Wholemount Culture

This video article demonstrates the establishment of organotypic retinal wholemount cultures and a cytospin procedure for analysis of exogenously induced effects. Organotypic retinal wholemount cultures mimic the in vivo situation and significantly facilitate the accessibility of murine retinas for experimental manipulations while circumventing the disadvantages of classical murine animal...

In vivo-like Organotypic Murine Retinal Wholemount Culture

derivation of leptomeninges explant cultures from postmortem human brain donors

Derivation of Leptomeninges Explant Cultures from Postmortem Human Brain Donors

The leptomeninges explant culture protocol from human postmortem brain is a technically robust and simple way to derive fibronectin-positive meningeal fibroblasts within 6-8 weeks and cryopreserve approximately 20-30 million...

generation of organotypic raft cultures from primary human keratinocytes

Generation of Organotypic Raft Cultures from Primary Human Keratinocytes

An in vitro method to mimic in vivo epithelial differentiation is described. Many viruses target epithelial cells as part of their viral life cycle, and this method provides a means of examining virus:host interactions that more closely resembles that which occurs in vivo. This technique can be used with primary keratinocytes, established cell lines, as well as normal or diseased biopsy...

retinal explant of the adult mouse retina as an ex vivo model for studying retinal neurovascular diseases

Retinal Explant of the Adult Mouse Retina as an Ex Vivo Model for Studying Retinal Neurovascular Diseases

This protocol presents and describes steps for the isolation, dissection, culturing, and staining of retinal explants obtained from an adult mouse. This method is beneficial as an ex vivo model for studying different retinal neurovascular diseases such as diabetic...

Retinal Explant of the Adult Mouse Retina as an Ex Vivo Model for Studying Retinal Neurovascular Diseases

characterization of a novel human organotypic retinal culture technique

Characterization of a Novel Human Organotypic Retinal Culture Technique

This study aims to develop a novel human organotypic retinal culture (HORC) model that prevents compromising retinal integrity during explant handling. This is achieved by culturing the retina with the overlying vitreous and the underlying retinal pigment&#160;epithelium-choroid (RPE-choroid) and...

organotypic hippocampal slice cultures

Organotypic Hippocampal Slice Cultures

We describe a method to prepare organotypic hippocampal slices that can be easily adapted to other brain regions.  Brain slices are laid on porous membranes and culture media is allowed to form an interface. This method preserves the gross architecture of the hippocampus for up to 2 weeks in...

preparation of organotypic slice cultures from a rat pup&#39;s hippocampus

This video demonstrates a method for preparing organotypic hippocampal slice cultures from the brain of a rat pup. It outlines the steps involved in the dissection of the hippocampus, slicing, and culture conditions required to promote cell viability and growth in the hippocampal slices, ultimately generating organotypic slice...

Preparation of Organotypic Slice Cultures from a Rat Pup&#39;s Hippocampus

View the medial face of the right hemisphere and identify the edge fornix, a prominent band of white matter along the medial edge of the hippocampus. Once identified, cut through the fornix using only about 0.5 centimeters of the scalpel blade. Using two micro-spatulas, remove the hippocampus by placing the right hand spatula on the brain stem and lifting the overlying cortex with a left hand...

primary cell cultures from the mouse retinal pigment epithelium

Primary Cell Cultures from the Mouse Retinal Pigment Epithelium

The retinal pigment epithelium (RPE) is a multi-functional epithelium of the eye. Here we present a protocol to establish primary cell cultures derived from the murine...

generation of primary retinal ganglion cell cultures from zebrafish embryos

The video demonstrates a method for culturing primary retinal ganglion cells from zebrafish embryos. Early-stage embryos undergo dissection to isolate the eyes, which are subsequently mechanically dissociated into a suspension of retinal ganglion cells. This cell suspension is cultured on coverslips coated with adhesive proteins to facilitate axon...

Generation of Primary Retinal Ganglion Cell Cultures From Zebrafish Embryos

purkinje cell survival in organotypic cerebellar slice cultures

Purkinje Cell Survival in Organotypic Cerebellar Slice Cultures

Organotypic slice cultures are a powerful tool to study neurodevelopmental or degenerative/regenerative processes. Here, we describe a protocol that models the neurodevelopmental death of Purkinje cells in mouse cerebellar slice cultures. This method may benefit research in neuroprotective drug...

multi-electrode array recordings of neuronal avalanches in organotypic cultures

Multi-electrode Array Recordings of Neuronal Avalanches in Organotypic Cultures

A robust way to study neuronal avalanches, i.e. scale-invariant spatio-temporal activity bursts, indicative of critical state dynamics in cortex.  Avalanches emerge spontaneously in developing superficial layers of cultured cortex which allows for long-term measurements of the activity with planar integrated multi-electrode arrays (MEA) under precisely controlled...

organotypic cerebellar cultures: apoptotic challenges and detection

Organotypic Cerebellar Cultures: Apoptotic Challenges and Detection

This method describes the generation of organotypic cerebellar cultures and the effect of certain apoptotic stimuli on the viability of different cerebellar cell types.

long-term, serum-free cultivation of organotypic mouse retina explants with intact retinal pigment epithelium

Long-Term, Serum-Free Cultivation of Organotypic Mouse Retina Explants with Intact Retinal Pigment Epithelium

The protocol describes organotypic explants of mouse neuroretina, cultivated together with its retinal pigment epithelium (RPE), in R16 defined medium, free of serum and antibiotics. This method is relatively simple to perform, less expensive, and time-consuming when compared to in vivo experiments, and can be adapted to numerous experimental...

organotypic slice cultures to study oligodendrocyte dynamics and myelination

Organotypic Slice Cultures to Study Oligodendrocyte Dynamics and Myelination

A technique to study NG2 cells and oligodendrocytes using a slice culture system of the forebrain and cerebellum is described.  This method allows examination of the dynamics of proliferation and differentiation of cells within the oligodendrocyte lineage where the extracellular environment can be easily manipulated while maintaining tissue...

extraction and analysis of cortisol from human and monkey hair

Extraction and Analysis of Cortisol from Human and Monkey Hair

Cortisol (CORT) accumulates in the growing hair shaft of humans and nonhuman primates. We describe methods for extracting and analyzing hair CORT with high precision and sensitivity. Measurement of hair CORT is particularly well-suited for assessing chronic stress over periods of weeks to...

Using a pair of fine forceps, position and hold embryos anterior to the yolk with one of the forceps, and remove the tail posterior to the yolk sac with the other forceps. Grab the neck with forceps and take off the head to expose the brain and eyes to the E2 media. With the tip of fine forceps, gently roll the eyes from the head while holding the cranial tissue down with the second forceps. Transfer four eyes to one of the previously prepared tubes containing...

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the strength of their connections after brief periods of strong activation. This phenomenon, known as long-term potentiation (LTP) can last for hours or days and has become the best candidate mechanism for learning and memory 2. In addition, the well defined anatomy and connectivity of the hippocampus 3 has made it a classical model system to study synaptic transmission and synaptic plasticity4.
As our understanding of the physiology of hippocampal synapses grew and molecular players became identified, a need to manipulate synaptic proteins became imperative. Organotypic hippocampal cultures offer the possibility for easy gene manipulation and precise pharmacological intervention but maintain synaptic organization that is critical to understanding synapse function in a more naturalistic context than routine culture dissociated neurons methods.
Here we present a method to prepare and culture hippocampal slices that can be easily adapted to other brain regions. This method allows easy access to the slices for genetic manipulation using different approaches like viral infection 5,6 or biolistics 7. In addition, slices can be easily recovered for biochemical assays 8, or transferred to microscopes for imaging 9 or electrophysiological experiments 10.

We describe a method to prepare organotypic hippocampal slices that can be easily adapted to other brain regions. Brain slices are laid on porous membranes and culture media is allowed to form an interface. This method preserves the gross architecture of the hippocampus for up to 2 weeks in culture.

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the ...

Organotypic cultures of neuronal tissue were first introduced by Hogue in 1947 1,2 and have constituted a major breakthrough in the field of neuroscience. Since then, the technique was developed further and currently there are many different ways to prepare organotypic cultures. The method presented here was adapted from the one described by Stoppini et al. for the preparation of the slices and from Gogolla et al. for the staining procedure 3,4.
A unique feature of this technique is that it allows you to study different parts of the brain such as hippocampus or cerebellum in their original structure, providing a big advantage over dissociated cultures in which all the cellular organization and neuronal networks are disrupted. In the case of the cerebellum it is even more advantageous because it allows the study of Purkinje cells, extremely difficult to obtain as dissociated primary culture. This method can be used to study certain developmental features of the cerebellum in vitro, as well as for electrophysiological and pharmacological experiments in both wild type and mutant mice.
The method described here was designed to study the effect of apoptotic stimuli such as Fas ligand in the developing cerebellum, using TUNEL staining to measure apoptotic cell death. If TUNEL staining is combined with cell type specific markers, such as Calbindin for Purkinje cells, it is possible to evaluate cell death in a cell population specific manner. The Calbindin staining also serves the purpose of evaluating the quality of the cerebellar cultures.

This method describes the generation of organotypic cerebellar cultures and the effect of certain apoptotic stimuli on the viability of different cerebellar cell types.

Organotypic cultures of neuronal tissue were first introduced by Hogue in 1947 1,2 and have constituted a major breakthrough in the field of neuroscience. ...

The cortex is spontaneously active, even in the absence of any particular input or motor output. During development, this activity is important for the migration and differentiation of cortex cell types and the formation of neuronal connections1. In the mature animal, ongoing activity reflects the past and the present state of an animal into which sensory stimuli are seamlessly integrated to compute future actions. Thus, a clear understanding of the organization of ongoing i.e. spontaneous activity is a prerequisite to understand cortex function. 
Numerous recording techniques revealed that ongoing activity in cortex is comprised of many neurons whose individual activities transiently sum to larger events that can be detected in the local field potential (LFP) with extracellular microelectrodes, or in the electroencephalogram (EEG), the magnetoencephalogram (MEG), and the BOLD signal from functional magnetic resonance imaging (fMRI). The LFP is currently the method of choice when studying neuronal population activity with high temporal and spatial resolution at the mesoscopic scale (several thousands of neurons). At the extracellular microelectrode, locally synchronized activities of spatially neighbored neurons result in rapid deflections in the LFP up to several hundreds of microvolts. When using an array of microelectrodes, the organizations of such deflections can be conveniently monitored in space and time. 
Neuronal avalanches describe the scale-invariant spatiotemporal organization of ongoing neuronal activity in the brain2,3. They are specific to the superficial layers of cortex as established in vitro4,5, in vivo in the anesthetized rat 6, and in the awake monkey7. Importantly, both theoretical and empirical studies2,8-10 suggest that neuronal avalanches indicate an exquisitely balanced critical state dynamics of cortex that optimizes information transfer and information processing.
In order to study the mechanisms of neuronal avalanche development, maintenance, and regulation, in vitro preparations are highly beneficial, as they allow for stable recordings of avalanche activity under precisely controlled conditions. The current protocol describes how to study neuronal avalanches in vitro by taking advantage of superficial layer development in organotypic cortex cultures, i.e. slice cultures, grown on planar, integrated microelectrode arrays (MEA; see also 11-14).

A robust way to study neuronal avalanches, i.e. scale-invariant spatio-temporal activity bursts, indicative of critical state dynamics in cortex. Avalanches emerge spontaneously in developing superficial layers of cultured cortex which allows for long-term measurements of the activity with planar integrated multi-electrode arrays (MEA) under precisely controlled conditions.

The cortex is spontaneously active, even in the absence of any particular input or motor output.  During development, this activity is important for the ...

Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro

The mouse is an excellent model organism to study mammalian brain development due to the abundance of molecular and genetic data. However, the developing mouse brain is not suitable for easy manipulation and imaging in vivo since the mouse embryo is inaccessible and opaque. Organotypic slice cultures of embryonic brains are therefore widely used to study murine brain development in vitro. Ex-vivo manipulation or the use of transgenic mice allows the modification of gene expression so that subpopulations of neuronal or glial cells can be labeled with fluorescent proteins. The behavior of labeled cells can then be observed using time-lapse imaging. Time-lapse imaging has been particularly successful for studying cell behaviors that underlie the development of the cerebral cortex at late embryonic stages 1-2. Embryonic organotypic slice culture systems in brain regions outside of the forebrain are less well established. Therefore, the wealth of time-lapse imaging data describing neuronal cell migration is restricted to the forebrain 3,4. It is still not known, whether the principles discovered for the dorsal brain hold true for ventral brain areas. In the ventral brain, neurons are organized in neuronal clusters rather than layers and they often have to undergo complicated migratory trajectories to reach their final position. The ventral midbrain is not only a good model system for ventral brain development, but also contains neuronal populations such as dopaminergic neurons that are relevant in disease processes. While the function and degeneration of dopaminergic neurons has been investigated in great detail in the adult and ageing brain, little is known about the behavior of these neurons during their differentiation and migration phase 5. We describe here the generation of slice cultures from the embryonic day (E) 12.5 mouse ventral midbrain. These slice cultures are potentially suitable for monitoring dopaminergic neuron development over several days in vitro. We highlight the critical steps in generating brain slices at these early stages of embryonic development and discuss the conditions necessary for maintaining normal development of dopaminergic neurons in vitro. We also present results from time lapse imaging experiments. In these experiments, ventral midbrain precursors (including dopaminergic precursors) and their descendants were labeled in a mosaic manner using a Cre/loxP based inducible fate mapping system 6.

Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro

A method to generate organotypic slices from the E12.5 murine embryonic midbrain is described. The organotypic slice cultures can be used to observe the behavior of dopaminergic neurons or other ventral midbrain neurons.

The  mouse is an excellent model organism to study mammalian brain development due  to the abundance of molecular and genetic data. However, the ...

The Analysis of Purkinje Cell Dendritic Morphology in Organotypic Slice Cultures

Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly oriented in the sagittal plane and develops mostly in the postnatal period in small rodents 3. Furthermore, several antibodies are available which selectively and intensively label Purkinje cells including all processes, with anti-Calbindin D28K being the most widely used. For viewing of dendrites in living cells, mice expressing EGFP selectively in Purkinje cells 11 are available through Jackson labs. Organotypic cerebellar slice cultures cells allow easy experimental manipulation of Purkinje cell dendritic development because most of the dendritic expansion of the Purkinje cell dendritic tree is actually taking place during the culture period 4. We present here a short, reliable and easy protocol for viewing and analyzing the dendritic morphology of Purkinje cells grown in organotypic cerebellar slice cultures. For many purposes, a quantitative evaluation of the Purkinje cell dendritic tree is desirable. We focus here on two parameters, dendritic tree size and branch point numbers, which can be rapidly and easily determined from anti-calbindin stained cerebellar slice cultures. These two parameters yield a reliable and sensitive measure of changes of the Purkinje cell dendritic tree. Using the example of treatments with the protein kinase C (PKC) activator PMA and the metabotropic glutamate receptor 1 (mGluR1) we demonstrate how differences in the dendritic development are visualized and quantitatively assessed. The combination of the presence of an extensive dendritic tree, selective and intense immunostaining methods, organotypic slice cultures which cover the period of dendritic growth and a mouse model with Purkinje cell specific EGFP expression make Purkinje cells a powerful model system for revealing the mechanisms of dendritic development.

We present a protocol that permits to view and to quantitatively asses the morphology of the dendritic tree of individual Purkinje cells grown in organotypic cerebellar slice cultures. This protocol is intended to promote studies on the mechanisms of Purkinje cell dendritic development.

Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly ...

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During axon outgrowth, the growth cone must integrate multiple sources of guidance cue information to modulate its cytoskeleton in order to propel the growth cone forward and accurately navigate to find its specific targets1. How this integration occurs at the cytoskeletal level is still emerging, and examination of cytoskeletal protein and effector dynamics within the growth cone can allow the elucidation of these mechanisms. Xenopus laevis growth cones are large enough (10-30 microns in diameter) to perform high-resolution live imaging of cytoskeletal dynamics (e.g.2-4 ) and are easy to isolate and manipulate in a lab setting compared to other vertebrates. The frog is a classic model system for developmental neurobiology studies, and important early insights into growth cone microtubule dynamics were initially found using this system5-7 . In this method8, eggs are collected and fertilized in vitro, injected with RNA encoding fluorescently tagged cytoskeletal fusion proteins or other constructs to manipulate gene expression, and then allowed to develop to the neural tube stage. Neural tubes are isolated by dissection and then are cultured, and growth cones on outgrowing neurites are imaged. In this article, we describe how to perform this method, the goal of which is to culture Xenopus laevis growth cones for subsequent high-resolution image analysis. While we provide the example of +TIP fusion protein EB1-GFP, this method can be applied to any number of proteins to elucidate their behaviors within the growth cone.

Culturing neural explants from dissected Xenopus laevis embryos that express fluorescent fusion proteins allows for imaging of growth cone cytoskeletal dynamics.

The complex process of axon guidance is largely driven by the growth cone, which is the dynamic motile structure at the tip of the growing axon. During ...

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During embryonic and postnatal development they actively proliferate and generate myelinating oligodendrocytes. These cells have commonly been studied in primary dissociated cultures, neuron cocultures, and in fixed tissue. Using newly available transgenic mouse lines slice culture systems can be used to investigate proliferation and differentiation of oligodendrocyte lineage cells in both gray and white matter regions of the forebrain and cerebellum. Slice cultures are prepared from early postnatal mice and are kept in culture for up to 1 month. These slices can be imaged multiple times over the culture period to investigate cellular behavior and interactions. This method allows visualization of NG2 cell division and the steps leading to oligodendrocyte differentiation while enabling detailed analysis of region-dependent NG2 cell and oligodendrocyte functional heterogeneity. This is a powerful technique that can be used to investigate the intrinsic and extrinsic signals influencing these cells over time in a cellular environment that closely resembles that found in vivo.

A technique to study NG2 cells and oligodendrocytes using a slice culture system of the forebrain and cerebellum is described. This method allows examination of the dynamics of proliferation and differentiation of cells within the oligodendrocyte lineage where the extracellular environment can be easily manipulated while maintaining tissue cytoarchitecture.

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During ...

The Analysis of Neurovascular Remodeling in Entorhino-hippocampal Organotypic Slice Cultures

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional deficits in the affected patients. Despite intensive research efforts, there is still no effective treatment option available that reduces neuronal injury and protects neurons in the ischemic areas from delayed secondary death. Research in this area typically involves the use of elaborate and problematic animal models. Entorhino-hippocampal organotypic slice cultures challenged with oxygen and glucose deprivation (OGD) are established in&#160;vitro models which mimic cerebral ischemia. The novel aspect of this study is that changes of the brain blood vessels are studied in addition to neuronal changes and the reaction of both the neuronal compartment and the vascular compartment can be compared and correlated. The methods presented in this protocol substantially broaden the potential applications of the organotypic slice culture approach. The induction of OGD or hypoxia alone can be applied by rather simple means in organotypic slice cultures and leads to reliable and reproducible damage in the neural tissue. This is in stark contrast to the complicated and problematic animal experiments inducing stroke and ischemia in vivo. By broadening the analysis to include the study of the reaction of the vasculature could provide new ways on how to preserve and restore brain functions. The slice culture approach presented here might develop into an attractive and important tool for the study of ischemic brain injury and might be useful for testing potential therapeutic measures aimed at neuroprotection.

A protocol for entorhino-hippocampal organotypic slice cultures, which allows reproducing many aspects of ischemic brain injury, is presented. By studying changes of the neurovasculature in addition to changes in the neurons, this protocol is a versatile tool to study plastic changes in neural tissue after injury.

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional ...

Investigating Functional Regeneration in Organotypic Spinal Cord Co-cultures Grown on Multi-electrode Arrays

Adult higher vertebrates have a limited potential to recover from spinal cord injury. Recently, evidence emerged that propriospinal connections are a promising target for intervention to improve functional regeneration. So far, no in vitro model exists that grants the possibility to examine functional recovery of propriospinal fibers. Therefore, a representative model that is based on two organotypic spinal cord sections of embryonic rat, cultured next to each other on multi-electrode arrays (MEAs) was developed. These slices grow and, within a few days in vitro, fuse along the sides facing each other. The design of the used MEAs permits the performance of lesions with a scalpel blade through this fusion site without inflicting damage on the MEAs. The slices show spontaneous activity, usually organized in network activity bursts, and spatial and temporal activity parameters such as the location of burst origins, speed and direction of their propagation and latencies between bursts can be characterized. Using these features, it is also possible to assess functional connection of the slices by calculating the amount of synchronized bursts between the two sides. Furthermore, the slices can be morphologically analyzed by performing immunohistochemical stainings after the recordings. 
Several advantages of the used techniques are combined in this model: the slices largely preserve the original tissue architecture with intact local synaptic circuitry, the tissue is easily and repeatedly accessible and neuronal activity can be detected simultaneously and non-invasively in a large number of spots at high temporal resolution. These features allow the investigation of functional regeneration of intraspinal connections in isolation in vitro in a sophisticated and efficient way.

Here we present a protocol that is based on spinal cord slices cultured on multi-electrode arrays to study functional regeneration of propriospinal connections in vitro.

Adult higher vertebrates have a limited potential to recover from spinal cord injury. Recently, evidence emerged that propriospinal connections are a ...

Even though great progress has been made in the clinical characterization of Parkinson&#39;s disease, several studies report that the diagnosis of Parkinson&#39;s disease is not pathologically confirmed in up to 25% of clinically diagnosed Parkinson&#39;s disease. Therefore, tissue collected from clinically diagnosed patients with idiopathic Parkinson&#39;s disease can have a high rate of misdiagnosis; hence in vitro studies from such tissues to study Parkinson&#39;s disease as a preclinical model can become futile.
By collecting postmortem human leptomeninges with a confirmed neuropathological diagnosis of Parkinson&#39;s disease and characterized by nigrostriatal cell loss and intracellular protein inclusions called Lewy bodies, one can be certain that clinically observed parkinsonism is not caused by another underlying disease process (e.g. tumor, arteriosclerosis).
This protocol presents the dissection and preparation of postmortem human leptomeninges for derivation of a meningeal fibroblast culture. This procedure is robust and has a high success rate. The challenge of the culture is sterility as the brain procurement is generally not performed under sterile conditions. Therefore, it is important to supplement the culture media with a cocktail of penicillin, streptomycin, and amphotericin B.
The derivation of meningeal fibroblasts from autopsy-confirmed cases with Parkinson&#39;s disease provides the foundation for in vitro modeling of Parkinson&#39;s disease. Meningeal fibroblasts appear 3-9 days after sample preparation and about 20-30 million cells can be cryopreserved in 6-8 weeks. The meningeal fibroblast culture is homogenous and the cells express fibronectin, a commonly used marker to identify meninges.

The leptomeninges explant culture protocol from human postmortem brain is a technically robust and simple way to derive fibronectin-positive meningeal fibroblasts within 6-8 weeks and cryopreserve approximately 20-30 million cells.