Apelin Receptor Signaling Protects GT1-7 GnRH Neurons Against Oxidative Stress In Vitro

• Published in: Cellular and molecular neurobiology Vol. 42; no. 3; pp. 753 - 775
• Main Authors: Şişli, Hatice Burcu, Hayal, Taha Bartu, Şenkal, Selinay, Kıratlı, Binnur, Sağraç, Derya, Seçkin, Selin, Özpolat, Murat, Şahin, Fikrettin, Yılmaz, Bayram, Doğan, Ayşegül
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.04.2022; Springer Nature B.V
• Subjects: AKT protein; Animals; Apelin Receptors - metabolism; Apoptosis; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cell culture; Cell death; Cell proliferation; Gonadotropin-releasing hormone; Gonadotropin-Releasing Hormone - pharmacology; Gonadotropins; Hydrogen Peroxide; Hypothalamic-pituitary-adrenal axis; Hypothalamus; Hypothalamus - metabolism; Hypoxia; Mice; Neurobiology; Neurons; Neurons - metabolism; Neurosciences; Original Research; Oxidative Stress; Pituitary; Pituitary (anterior); siRNA; Stem cells; Stress response; Oxidative stress; Gonadotropin-releasing hormone; Apelin receptor; Hypothalamus; Apelin
• ISSN: 0272-4340; 1573-6830
• DOI: 10.1007/s10571-020-00968-2

Hypothalamic–pituitary–adrenal (HPA) axis regulates stress response in the body and abnormal increase in oxidative stress contributes to the various disease pathogenesis. Although hypothalamic distribution of Apelin receptor (APLNR) has been studied, the potential regulatory role in hormone releasing function of hypothalamus in response to stress is not well elucidated yet. To determine whether APLNR is involved in the protection of the hypothalamus against oxidative stress, gonadotropin-releasing hormone (GnRH) cells were used as an in vitro model system. GT1-7 mouse hypothalamic neuronal cell line was subjected to H 2 O 2 and hypoxia induced oxidative stress under various circumstances including APLNR overexpression, knockdown and knockout. Overexpression and activation of APLNR in GnRH producing neurons caused an increase in cell proliferation under oxidative stress. In addition, blockage of APLNR function by siRNA reduced GnRH release. Activation of APLNR initiated AKT kinase pathway as a proliferative response against hypoxic culture conditions and blocked apoptosis. Although expression and activation of APLNR have not been related to GnRH neuron differentiation during development, positive contribution of activated APLNR signaling to GnRH release in mouse embryonic stem cell derived GnRH neurons was observed in the present study. Sustained overexpression and complete deletion of APLNR in mouse embryonic stem cell derived GnRH neurons reduced GnRH release in vitro. The present findings suggest that expression and activation of APLNR in GnRH releasing GT1-7 neurons might induce a protective mechanism against oxidative stress induced cell death and APLNR signaling may play a role in GnRH neurons.