Effect of TrkA and p75NTR on the Survival of Neurons in the Cultured Organotypic Hippocampal Slice

J Korean Neurol Assoc > Volume 24(6); 2006 > Article

Journal of the Korean Neurological Association 2006;24(6): 564-570.

배양된 기관형적 해마 절편에서 TrkA와 p75NTR의 발현이 신경세포의 생존에 미치는 영향

양동원, 권오주a 김영인 김범생

가톨릭대학교 의과대학 신경과학교실, 생화학교실a

Effect of TrkA and p75NTR on the Survival of Neurons in the Cultured Organotypic Hippocampal Slice

Dong Won Yang

Departments of Neurology, Biochemistrya, The Catholic University of Korea, College of Medicine, Seoul, Korea

Abstract

Background: Nerve growth factor (NGF) promotes the survival and differentiation of vertebrate neurons, and their actions are mediated by two classes of cell surface receptors: tyrosine kinase A receptor (TrkA) and p75 neurotrophic receptor (p75NTR). We evaluated the role of NGF receptors in neuronal survival and the physical interactions between them.
Methods: Organotypic hippocampal slices were obtained from 5 to 7-day-old rat pups and were grown for 14 days in vitro. The expression of the TrkA and p75NTR was evaluated by the western blot and immunohistochemical methods. The neuroprotective effect of NGF on the blocking of antibody-induced neuronal cell death was tested by the application of NGF (0, 50 and 150 ng/ml) to the culture media in the presence of 200 ng/ml of blocking antibodies against TrkA and p75NTR. Functional interactions between the two receptors were examined using the immunoprecipitation method.
Results: TrkA and p75NTR were co-expressed in the principal neurons of the hippocampal slice culture, and the expression level was increased time dependently until 14 days of culture. The blocking antibody against each receptor induced neuronal damage in time and dose-dependent manners. NFG delayed or prevented the blocking antibody from inducing neuronal damage. Results from the immunoprecipitation experiment showed physical interactions between the two NGF receptors.
Conclusions: Our results indicate that the co-expressed NGF receptors, TrkA and p75NTR, might have protective roles in the survival of neuronal cells through the cooperative interactions between them. KeyWords:Nerve growth factor (NGF), Tyrosine kinase A receptor, p75 neurotrophic receptor, Neurotrophin, Organotypic hippocampal slice culture