Single-nucleus transcriptomic analysis reveals the relationship between gene expression in oligodendrocyte lineage and major depressive disorder.

BACKGROUND: Major depressive disorder (MDD) is a common mental illness that affects millions of people worldwide and imposes a heavy burden on individuals, families and society. Previous studies on MDD predominantly focused on neurons and employed bulk homogenates of brain tissues. This paper aims to decipher the relationship between oligodendrocyte lineage (OL) development and MDD at the single-cell resolution level. METHODS: Here, we present the use of a guided regularized random forest (GRRF) algorithm to explore single-nucleus RNA sequencing profiles (GSE144136) of the OL at four developmental stages, which contains dorsolateral prefrontal cortex of 17 healthy controls (HC) and 17 MDD cases, generated by Nagy C et al. We prioritized and ordered differentially expressed genes (DEGs) based on Nagy et al., which could predominantly discriminate cells in the four developmental stages and two adjacent developmental stages of the OL. We further screened top-ranked genes that distinguished between HC and MDD in four developmental stages. Moreover, we estimated the performance of the GRRF model via the area under the curve value. Additionally, we validated the pivotal candidate gene Malat1 in animal models. RESULTS: We found that, among the four developmental stages, the onset development of OL (OPC2) possesses the best predictive power for distinguishing HC and MDD, and long noncoding RNA MALAT1 has top-ranked importance value in candidate genes of four developmental stages. In addition, results of fluorescence in situ hybridization assay showed that Malat1 plays a critical role in the occurrence of depression. CONCLUSIONS: Our work elucidates the mechanism of MDD from the perspective of OL development at the single-cell resolution level and provides novel insight into the occurrence of depression.

Drynaria fortunei improves lipid profiles of elderly patients with postmenopausal osteoporosis via regulation of Notch1-NLRP3 inflammasome-mediated inflammation.

BACKGROUND: Dyslipidemia is a common comorbidity in elderly patients with postmenopausal osteoporosis (PMOP). Drynaria fortunei (Rhizoma drynariae) is well-known in traditional Chinese medicine for its ability to improve bone mineral density (BMD). However, whether and how Drynaria fortunei improves plasma lipid profiles in elderly PMOP patients remains unclear. METHODS: Eighty elderly female patients with concurrent PMOP and hyperlipemia were randomly assigned to Drynaria fortunei 2(n = 40) or control (n = 40) groups. The clinical efficacies of Drynaria fortunei were evaluated. At 0, 3-, 6-, 9-, and 12-month of follow-up, plasma levels of IL-1ß, IL-18, TNF-α, IL-6, IL-8, and IL-10 were measured using ELISA, whereas PBMC levels of NLRP3, ASC, caspase-1, NF-κB, SIRT1, and Notch1 were measured using RT-qPCR. PBMC isolated from PMOP patients were cultured and treated with Drynaria fortunei to determine its influence on NLRP3 inflammasome and associated cytokines. RESULTS: Drynaria fortunei effectively improved patients' BMD and lipid profiles. IL-1ß, IL-18, TNF-α, IL-6, IL-8 levels, as well as inflammasome-molecules of NLRP3, ASC, caspase-1, and NF-κB increased over time in the control group, but were significantly attenuated with Drynaria fortunei administration. In vitro, Drynaria fortunei suppressed NLRP3 inflammasome and associated cytokines by increasing SIRT1 or decreasing Notch1. Drynaria fortunei had inhibitory effects on NLRP3 inflammasome and Notch1 even when SIRT1 expression was suppressed. CONCLUSIONS: Drynaria fortunei has been demonstrated to significantly improve lipid profiles for elderly PMOP patients. Drynaria fortunei may down-regulate Notch1 independently of SIRT1 to suppress NLRP3 inflammasome-mediated inflammation, thus improving plasma lipid profile.