Adult Goat Retinal Neuronal Culture: Applications in Modeling Hyperglycemia

Abstract

Culture of adult neurons of the central nervous system (CNS) can provide a unique model system to explore neurodegenerative diseases. The CNS includes neurons and glia of the brain, spinal cord and retina. Neurons in the retina have the advantage of being the most accessible cells of the CNS, and can serve as a reliable mirror to the brain. Typically, primary cultures utilize fetal rodent neurons, but very rarely adult neurons from larger mammals. Here, we cultured primary retinal neurons isolated from adult goat up to 10 days, and established an in vitro model of hyperglycemia for performing morphological and molecular characterization studies. Immunofluorescence staining revealed that approximately 30–40% of cultured cells expressed neuronal markers. Next, we examined the relative expression of cell adhesion molecules (CAMs) in adult goat brain and retina. We also studied the effect of different glucose concentrations and media composition on the growth and expression of CAMs in cultured retinal neurons. Hyperglycemia significantly enhances neurite outgrowth in adult retinal neurons in culture. Expression of CAMs such as Caspr1, Contactin1 and Prion is downregulated in the presence of high glucose. Hyperglycemia downregulates the expression of the transcription factor CCAAT/enhancer binding protein (C/EBP α), predicted to bind CAM gene promoters. Collectively, our study demonstrates that metabolic environment markedly affects transcriptional regulation of CAMs in adult retinal neurons in culture. The effect of hyperglycemia on CAM interactions, as well as related changes in intracellular signaling pathways in adult retinal neurons warrants further investigation.

Aqueous Fibronectin Correlates With Severity of Macular Edema and Visual Acuity in Patients With Branch Retinal Vein Occlusion: A Proteome Study

“…Contactin-1 is a cell adhesion protein involved in axonal organization in early central nervous system development. 45 Retinal contactin-1 has been found to be downregulated following hyperglycemia, 46 indicating that contactin-1 is downregulated in retinal stress.…”

Optimized culture of retinal ganglion cells and amacrine cells from adult mice

“…Optimization of our culture conditions revealed inverse differences in base media on their effects on cell survival versus the percentage of cells with neurite processes in RGCs and CD15 + neurons. The different base media differ by osmolarity ranking in osmotic concentration as N < NA < DN = DW < DNA [59,60]. RGCs and CD15 + cells exposed to lower osmolarity (N) increased in cell viability, contrary to adult hippocampal neuronal cultures.…”

MeCP2 Is an Epigenetic Factor That Links DNA Methylation with Brain Metabolism

“…This mildly lower rate of glucose metabolism was also explored in one study using Mecp2 null mice that demonstrated how impairment of enzymes such as voltage-dependent anion channel 3 (VDAC3) (abundant in the outer mitochondria membrane), cytochrome C oxidase subunit 5a (COX5a) (complex IV), NADH dehydrogenase-ubiquinone 1 beta subcomplex subunit 8 (NDUFB8) (Complex I), and ATP synthase F1 subunit β (ATP5B) (Complex V) in the respiratory complexes of neuronal mitochondria, resulted in significant redox imbalance [ 24 ]. Additionally, an in vitro study demonstrated that cultured retinal neurons from adult goats in a hyperglycemic condition (25 mM of glucose) compared to a normal condition (5 mM) for 10 days, grew with abnormal length [ 185 ]. A recent study proposed significantly increased expression of MeCP2 and HDAC1 in streptozotocin-induced hyperglycemic mice, suggesting a strong connection between glucose metabolism and MeCP2 [ 186 ].…”