AIM
Neuroinflammation has been implicated in the pathogenesis of major depressive disorder (MDD), with interferon regulatory factor 1 (IRF1) playing a potential role. MicroRNAs (miRs) are also involved in MDD through posttranscriptional regulation of gene expression. This study investigated whether miR-20a-5p regulates IRF1 in MDD.
METHODS
IRF1 mRNA and miR-20a-5p expression levels were measured by qPCR in postmortem hippocampi from 14 MDD subjects and 14 controls, and in chronic social defeat stress (CSDS) mice. Their regulatory relationship was examined in HEK293 cells using miR-20a-5p overexpression and a dual-luciferase assay. Neuro2a cells treated with DMSO were used to evaluate the effects of cellular stress on Irf1 and miR-20a-5p expression.
RESULTS
IRF1 mRNA and miR-20a-5p expression levels were significantly increased in both MDD hippocampi and CSDS mice. Luciferase assays showed that miR-20a-5p directly targeted the conserved seed sequence within the IRF1 3'-UTR and suppressed IRF1 expression. During the early phase of cellular stress, Irf1 mRNA was upregulated, whereas miR-20a-5p was downregulated, suggesting that stress initially induces Irf1 expression, followed by secondary regulation of miR-20a-5p.
CONCLUSION
IRF1 mRNA expression was increased in the hippocampus of both MDD subjects and CSDS mice. Moreover, miR-20a-5p directly targeted the IRF1 3'-UTR, supporting a potential miR-20a-5p-IRF1 regulatory axis involved in inflammatory signaling in MDD. However, its functional significance in vivo remains to be determined.
Mariko Okano, Yuta Yoshino, Anuj K. Verma et al.· Psychiatry and Clinical Neur...· 0 citations
OBJECTIVE
Major Depressive Disorder (MDD) is a leading global cause of disability, marked by persistent mood disturbances, cognitive deficits, and changes in prefrontal cortex neural circuitry. In this study, we aimed to define cell-type-specific molecular and regulatory mechanisms underlying MDD by mapping gene-expression and chromatin-accessibility changes in the dorsolateral PFC (dlPFC).
METHODS
Postmortem dlPFC (BA9) tissue from 7 MDD and 8 well-matched controls was analyzed using 10x Genomics snRNA-seq and paired ATAC+RNA multiome sequencing. Sequencing data were processed with Cell Ranger pipelines, nuclei were filtered for quality and doublets/debris, and datasets were integrated and clustered using Seurat/Signac packages. Differential gene expression, chromatin accessibility, and transcription factor motif activity were tested between MDD and controls within each cell type, followed by peak-to-gene linkage and GO/KEGG and PsyGeNET enrichment to interpret dysregulated regulatory mechanisms.
RESULTS
A total of 20 distinct clusters encompassing major neuronal and non-neuronal populations were identified. Differential analyses uncovered extensive cell type-specific changes in chromatin accessibility and gene expression, particularly within excitatory layer 5/6 and inhibitory Pvalb neurons, as well as glial and vascular populations. Functional enrichment indicated dysregulation of synaptic organization, neurotransmission, myelination, stress-response, and immune-regulatory pathways across neuronal and non-neuronal cells. Notably, glucocorticoid-responsive transcription factors NR3C1/NR3C2 exhibited conserved regulatory networks implicating stress signaling in MDD pathophysiology.
CONCLUSIONS
Together, these findings provide a comprehensive single-nucleus atlas of gene regulation in the MDD PFC, highlighting coordinated dysfunction across neurons, glia, and vascular cells.
A. Francis, Y. Dwivedi· International Journal of Neu...· 0 citations
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