IFCPAR AR (ENGLISH) for CD - CEFIPRA

CEFIPRA
Centre Franco-Indien pour la Promotion de la Recherche Avancée
Project 3603-2
JUXTACRINE AND/OR PARACRINE CONTROL OF BRAIN
PLASTICITY
Duration: Three years and six months (September, 2007 to
February, 2011)
Objectives
i) Expression of PSA-NCAM on GnRH neuron terminals and
astrocytes in the median eminence region of hypothalamus
before the surge release of GnRH in proestrous phase
ii) Study whether Polysialyltransferase (PST) enzyme regulates the
addition of PSA to NCAM on GnRH neurons, astrocytes and
tanycytes
iii) To study the effect of Endo-N-treatment on matrix
metalloproteinases (MMP) activity in median eminence by
using both gel and in situ zymography in vivo and in vitro mixed
neuronal-glial cultures. Also to determine the effect of Endo-Ntreatment
on EGF receptor activation within the median
eminence in vivo and in vitro
Accomplishments
i) The enhanced expression of PSA-NCAM on GnRH neuron
terminals and astrocytes in the median eminence region of
hypothalamus before the surge release of GnRH observed in
proestrous phase suggests that PSA-NCAM plays a permissive
role to reduce glial coverage of GnRH terminals
ii) GnRH neuron in vivo shows changes in PST expression during
the proestrous and diestrous phases by ISH and northern
blotting techniques. To further confirm that PSA-NCAM plays
permissive role in GnRH neuron plasticity, the effect of
endoneuraminidase (Endo-N which specifically cleaves PSA
from NCAM) treatment was studied on estrous cyclicity and the
expression of GnRH and GFAP (astrocytic marker) in median
eminence by dual immunohistofluorescence labeling
iii) In vitro mixed neuronal-glial cultures were established using
GFP-GnRH mice but the number of GnRH cells in these cultures
were seen to be very low. Subsequently, GnV (conditionally
immortalized GnRH cell line) and astrocytes co-cultures were
established to achieve the proposed objective. The functional
contribution of PSA-NCAM in neuronal-glial plasticity were
assessed using both in vitro and in vivo systems. Using in vitro
model, structural remodeling of GnV-3 cells was studied after
treating the cells with Endo N enzyme, which specifically cleaves
PSA residues on NCAM
iv) Further in vivo study was carried out by stereotaxic injection of
endo N in lateral ventricle and immunostaining of GnRH, PSA-
NCAM and GFAP in the ME-ARC region of hypothalamus
v) The study results identify both MMP-2 and MMP-9 as
metalloproteinases involved in the control of the accessibility of
GnRH to the portal vasculature on the base or their expression
pattern in the ME of the hypothalamus and their enzymatic
activity in vivo and in vitro
Research papers published: Seven
Papers presented in Conferences : 15
Research Activities 2010-11
Life and Health Sciences
Prof. Gurcharan Kaur
Department of Biotechnology
Guru Nanak Dev University
Amritsar
Prof. Vincent Prevot
Institut National de la Recherche
Médicale, U837 Lille
GnRH-GFP neuron (green) + GFAPimmunoreactive
astrocytes (red) and MAP-2immunoreactive
neurons in a primary culture
from P0 GnRH-GFP mice.
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