Clinical Psychopharmacology and Neuroscience Papers in Press available online.

Effects Of Social Defeat Stress On Microtubule Regulating Proteins And Tubulin Polymerization
Thi-Hung Le 1,2, Jung-Mi Oh 3, Fatima Zahra Rami 1,2, Ling Li 1,2, Sung-Kun Chun 3, Young-Chul Chung 1,2,*
1Department of Psychiatry, Jeonbuk National University Medical School, Jeonju 561-712, Korea, 2Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 561-712, Korea, 3Department of Physiology, Jeonbuk National University Medical School, Jeonju 54907, Korea
Objective: Microtubule (MT) stability in neurons is vital for brain development; instability is associated with neuropsychiatric disorders. The present study examined the effects of social defeat stress (SDS) on MT-regulating proteins and tubulin polymerization.
Methods: After 10 days of SDS, defeated mice were separated into susceptible (Sus) and unsusceptible (Uns) groups based on their performance in a social avoidance test. Using extracted brain tissues, we measured the expression levels of α-tubulin, acetylated α-tubulin, tyrosinated α-tubulin, MT-associated protein-2 (MAP2), stathmin (STMN1), phospho stathmin serine 16 [p-STMN1 (Ser16)], phospho stathmin serine 25 [p-STMN1 (Ser25)], phospho stathmin serine 38 [p-STMN1 (Ser38)], stathmin2 (STMN2), phospho stathmin 2 serine 73 [p-STMN2 (Ser73)], 78-kDa glucose-regulated protein (GRP-78), and CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP) using Western blot assay. The tubulin polymerization rate was also measured.
Results: We observed increased and decreased expression of acetylated and tyrosinated α-tubulin, respectively, decreased expression of p-STMN1 (Ser16) and increased expression of p-STMN1 (Ser25), p-STMN2 (Ser73) and GRP-78 and CHOP in the prefrontal cortex and/or hippocampus of defeated mice. A reduced tubulin polymerization rate was observed in the Sus group compared to the Uns and Con groups.
Conclusions: Our findings suggest that SDS has detrimental effects on MT stability, and a lower tubulin polymerization rate could be a molecular marker for susceptibility to SDS.
Accepted Manuscript [Submitted on 2023-03-18, Accepted on 2023-06-21]