Asprosin expression and its role in regulating proliferation, cell cycle, and apoptosis in mouse hippocampal HT-22 cells.

Abstract

Asprosin is a profibrillin-1-derived protein hormone involved in energy metabolism, glucose homeostasis, and appetite. Although asprosin can cross the blood-brain barrier and act within the central nervous system, its direct role in hippocampal neurons remains unclear. This study examined asprosin system components and the effects of asprosin on metabolic activity, proliferation, reactive oxygen species (ROS) production, cell cycle progression, apoptosis, and intracellular signaling in mouse hippocampal HT-22 cells. Asprosin, Furin, and Olfr734 expression was assessed by Western blot and immunocytochemistry, whereas intracellular and secreted asprosin levels were quantified by ELISA. Cells were treated with asprosin over 0.01-100 nM, and low nanomolar doses were selected for detailed cell cycle, apoptosis, and signaling analyses. Metabolic activity, proliferation, ROS production, cell cycle distribution, and apoptosis were evaluated using alamarBlue, bromodeoxyuridine incorporation, ROS detection, and flow cytometry assays. Selected ROS-, cell cycle-, and apoptosis-related markers were analyzed by reverse transcription quantitative polymerase chain reaction and Western blot. PKA and ERK1/2 involvement was assessed by phosphorylation analysis and pharmacological inhibition. HT-22 cells expressed Asprosin, Furin, and Olfr734. Asprosin regulated cellular responses in a dose- and time-dependent manner: low nanomolar doses generally supported metabolic and proliferative activity, whereas 10 and 100 nM reduced these parameters. Asprosin did not markedly increase total ROS production but modulated Hmox1 and Sod2 expression. It also altered cell cycle distribution, apoptosis-related parameters, PKA and ERK1/2 phosphorylation, and inhibitor-sensitive expression of Ccne1, Bax, and Bcl2. These findings identify, for the first time, a functional asprosin system in mouse HT-22 hippocampal neurons.