Enzymatic removal of polysialic acid from neural cell adhesion molecule interrupts gonadotropin releasing hormone (GnRH) neuron-glial remodeling.

There is abundant evidence to prove that the astrocytes are highly dynamic cell type in CNS and under physiological conditions such as reproduction, these cells display a remarkable structural plasticity especially at the level of their distal processes ensheathing the gonadotropin releasing hormone (GnRH) axon terminals. The morphology of GnRH axon terminals and astrocytes in the median eminence region of hypothalamus show activity dependent structural plasticity during different phases of estrous cycle. In the current study, we have assessed the functional contribution of ∞-2,8-linked polysialic acid (PSA) on neural cell adhesion molecule (PSA-NCAM) in this neuronal-glial plasticity using both in vitro and in vivo model systems. In vivo experiments were carried out after stereotaxic injection of endoneuraminidase enzyme (endo-N) near median eminence region of hypothalamus to specifically remove PSA residues on NCAM followed by localization of GnRH, PSA-NCAM and glial fibrillary acidic protein (GFAP) by immunostaining. Using in vitro model, structural remodeling of GnV-3 cells, (a conditionally immortalized GnRH cell line) co-cultured with primary astrocytes was studied after treating the cells with endo-N. Marked morphological changes were observed in GnRH axon terminals in proestrous phase rats and control GnV-3 cells as compared to endo-N treatment i.e. after removal of PSA. The specificity of endo-N treatment was also confirmed by studying the expression of PSA-NCAM by Western blotting in cultures treated with and without endo-N. Removal of PSA from surfaces with endo-N prevented stimulation associated remodeling of GnRH axon terminals as well as their associated glial cells under both in vivo and in vitro conditions. The current data confirms the permissive role of PSA to promote dynamic remodeling of GnRH axon terminals and their associated glia during reproductive cycle in rats.

Kumar S ，Parkash J ，Kataria H ，Kaur G ... -  《-》

Neuronal-glial plasticity in gonadotropin-releasing hormone release in adult female rats: role of the polysialylated form of the neural cell adhesion molecule.

Parkash J ，Kaur G 《JOURNAL OF ENDOCRINOLOGY》

Potential of PSA-NCAM in neuron-glial plasticity in the adult hypothalamus: role of noradrenergic and GABAergic neurotransmitters.

Parkash J ，Kaur G 《BRAIN RESEARCH BULLETIN》

Neuroendocrine plasticity in GnRH release during rat estrous cycle: correlation with molecular markers of synaptic remodeling.

Kaur G ，Heera PK ，Srivastava LK 《BRAIN RESEARCH》

Transcriptional regulation of PSA-NCAM mediated neuron-glial plasticity in the adult hypothalamus.

Parkash J ，Kaur G 《-》