ABSTRACT
The puberty and reproduction are regulated by the hypothalamic-pituitary-gonadal axis. The activation of hypothalamic gonadotropin-releasing hormone (GnRH) neurons and an increase in GnRH is critical for the initiation of puberty. The mechanism of GnRH regulation for neurons activity is complicated, because many different factors can affect the secretion of GnRH. Glutamate is the main excitatory neurotransmitter, which can promote the secretion of GnRH through a variety of pathways. In recent years, relevant studies showed that NELL2 may influence the secretion of GnRH by regulating the secretion of glutamate or through other pathways,thereby affecting the onset of puberty. So NELL2 plays an important role in promoting neuronal growth,differentiation, neuronal plasticity maintenance and synapse transportation etc.
ABSTRACT
PURPOSE: Because NELL2 expression is strictly restricted only in neurons in developing and post- differentiated neural tissues, it is thought to be involved in the neuronal differentiation during development and in the maintenance of neuronal physiology in the post-differentiated neurons. In this study, we examined whether NELL2 is involved in the regulation of cell cycle and apoptosis in the hippocampal neuroprogenitor HiB5 cells. METHODS: Effects of NELL2 on the cultured HiB5 cell numbers, DNA fragmentation, and proteins involved in the regulation of the cell cycle were measured. RESULTS: NELL2 induced a decrease in cell numbers and an increase in G1 phase arrest. Moreover, transfection of NELL2 resulted in an increase of DNA fragmentation that shows an evidence of apoptosis. Contents of proteins involved in the regulation of cell cycle were also changed by transfection of NELL2 expression vectors. CONCLUSION: This study suggests that NELL2 plays an important role in the regulation of cell cycle and apoptosis of neurons.