Biologie cellulaire et du développement
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VDR Potentiation and NMDA R Inhibition Facilitates Axo-Dendritic Process Formation in Melanocyte Model for Pigmented Cells in Parkinsonism

Ogundele Olalekan Michael, Ajonijebu, Duyilemi Chris, Okunnuga Adedotun Adetokunbo, Adekeye Adeshina Oloruntoba and Ojo Abiodun Ayodele

Background: A major cellular change in dopaminergic neurons leading to Parkinsonism is the alteration of microtubule proteins that causes accumulation of tau protein, α-syn and β-amyloid plaque in the cells. In this study we investigate the role of Vitamin D3 in relieving the symptoms of Parkinsonism as it is capable of stimulating polymerization of microtubules. The Microtubules (MT) system in the fish scale melanocytes has been modeled for the dopaminergic neurons of the Substantia Nigra (SN). These cells are capable of forming cellular processes similar to what is seen in the dopaminergic neurons; in this study, we investigate the protective effect of Vitamin D3 Receptor Agonist (VDRA) and N-Methyl-D-Aspartate Receptor (NMDA R) inhibition in process formation, synaptic denervation and melanin loss in fish scale melanocytes modeled as pigmented adrenergic cells.

Method: The Tilapia scale was isolated and sub cultured in Ringer’s solution following which the cells were prepared for imaging. We incubated the cells with VDRA, Ketamine and a combination of Ketamine and VDRA in separate set ups for 60 minutes. Using brightfield imaging techniques, the cells were viewed during the incubation period and recorded using a Cameroscope connected to a computer interface.

Results/Conclusion: The cells incubated with VDRA and NMDA R inhibitor, showed an increase in the number of process and extent of the process formation; the increased number of process is an indication of a rapid rate of polymerization of microtubules. Also, the processes formed are combined long processes peculiar to the NMDA R1 inhibition and short processes characteristic of VDR potentiation as seen in VDRA treatment only. Most of the effects of the VDRA were restricted to process formation around the cell body; this is similar to the microtubule cytoskeletal system found in the dendritic nucleation assembly. This finding confirms the presence of VDR and its likely restriction to d cell body plus its role in facilitating short dendrite-like process formation while NMDA R is located on the processes and facilitates long process formation.