Silent information regulator 2 (Sirtuin2 / SIRT2) is a NAD⁺-dependent deacetylase that regulates the cellular oxidative stress response. It modulates transcriptional silencing and protein stability through deacetylation of target proteins including histones. Previous studies have shown that SIRT2 plays a role in mood disorders and hippocampus-dependent cognitive function, but the underlying neurobiological mechanism is poorly understood. Here, we report that chronic stress suppresses SIRT2 expression in the hippocampus. Molecular and biochemical analyses indicate that the stress-induced decrease in the SIRT2 expression downregulates synaptic plasticity-related genes in the hippocampus through the increase of euchromatic histone-lysine N-methyltransferase 2 (Ehmt2) (also known as G9a). shRNA-mediated knockdown of SIRT2 in the dentate gyrus alters the expression of synaptic plasticity-related genes in a way similar to those induced by chronic stress, and produces depression-like behaviors. Our results indicate that SIRT2 plays an important role in the response to stress, thereby modulating depression-like behaviors.
Cognition ; Dentate Gyrus ; Depression ; Down-Regulation ; Hippocampus ; Histone-Lysine N-Methyltransferase ; Histones ; Mood Disorders ; Neuronal Plasticity ; Oxidative Stress ; Protein Stability ; Up-Regulation

Objective: Bone morphogenetic protein receptor type 2 (BMPR2) has been associated with radiographic changes in ankylosing spondylitis (AS), but further characterization of the cellular signaling pathway in osteoprogenitor (OP) is not clearly understood.The aim of this study was to investigate the expression of BMPR2 and bone morphogenetic protein 2 (BMP2)-mediated responsibility in AS. Methods: We collected 10 healthy control (HC) and 14 AS-OPs derived from facet joints. Subsequently, we then conducted RNA sequencing with two samples per group and selected BMP-related genes. Facet joint tissues and derived primary OPs were evaluated by validation of selected RNA sequencing data, immunohistochemistry, and comparison of osteogenic differentiation potential. Results: Based on RNA-sequencing analysis, we found that BMPR2 expression is higher in AS-OPs compared to in HC-OPs. We also validated the increased BMPR2 expression in facet joint tissues with AS and its derived OPs in messenger RNA and protein levels. Additionally, primary AS-OPs showed much greater response to osteogenic differentiation induced by BMP2 and a higher capacity for smad1/5/8-induced RUNX2 expression compared to HCs. Conclusion The expression of BMPR2 was found to be significantly increased in facet joint tissues of patients with AS. These findings suggest that BMPR2 may play a role in the BMP2-mediated progression of AS.