Altered expression of NUCB2/nesfatin-1 in plasma, hypothalamus and brainstem is associated with HPA axis activity and TPH expression in chronically stressed rats.

The anorectic peptide nesfatin-1 has been identified as a potential mood regulator. Abnormal nesfatin-1 expression has been observed in both depression animal models and clinical cohorts, but its exact role in depression pathogenesis remains unclear. This study aimed to detect peripheral and central nesfatin-1 alterations in rats with chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors, and explore their correlations with hypothalamic-pituitary-adrenal (HPA) axis activity and brainstem monoamine synthesis. Rats were subjected to 5-week CUMS. Enzyme-linked immunosorbent assay (ELISA) quantified plasma mature nesfatin-1 peptide, and Western blot (WB) detected full-length nucleobindin 2 (NUCB2)/nesfatin-1 in the hypothalamus and brainstem. Spearman's rank correlation was performed solely within the CUMS group (n = 6); these exploratory correlational findings require cautious interpretation due to small sample size. CUMS significantly increased plasma nesfatin-1 as well as hypothalamic and brainstem NUCB2/nesfatin-1. In CUMS rats, plasma nesfatin-1 was positively correlated with corticosterone and forced swim test (FST) immobility time, and negatively correlated with sucrose preference index(SPT) and weight gain. Brainstem NUCB2/nesfatin-1 showed a positive correlation with tryptophan hydroxylase (TPH), while no significant correlation was found between hypothalamic NUCB2/nesfatin-1 and all measured parameters. Chronic stress-induced nesfatin-1 elevation accompanies peripheral HPA hyperactivation and aggravated depressive-like behaviors. Brainstem NUCB2/nesfatin-1 positively correlates with TPH, suggesting NUCB2/nesfatin-1 may link neuroendocrine activity and serotonergic plasticity with the brainstem as a core site. This study provides preliminary correlational evidence for coordinated NUCB2/nesfatin-1 changes across peripheral and central systems under stress-induced depression.