Biomedical subjects

Aleena Francis

Publications and source records attributed to Aleena Francis.

3 recordsLinked to original sources

PubMed2026

Multiomic single-nucleus profiling reveals cell-type-specific epigenetic and transcriptional dysregulation in major depressive disorder brain.

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 prefrontal cortex (PFC) (dlPFC). METHODS: Postmortem dlPFC (BA9) tissue from 7 MDD and 8 well-matched controls was analyzed using 10× 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 Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway 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.

Major Depressive Disorder↗

PubMed2026

Integrative methylation and miRNA dysregulation in dlPFC reveal distinct molecular signatures of suicide and non-suicide subtypes in major depressive disorder.

AIM: Major depressive disorder (MDD) is a leading cause of disability and carries a high risk of suicide. MicroRNAs (miRNAs) are epigenetic regulators implicated in MDD and can be regulated by DNA methylation, potentially reshaping downstream gene networks. We investigated methylation-linked miRNA dysregulation and explored whether these changes are specifically associated with suicide among MDD patients. METHODS: Genome-wide DNA methylation profiling of the dorsolateral prefrontal cortex from 15 MDD patients who died by suicide (MDD+S), 17 MDD patients who died from causes other than suicide (MDD-S), and 16 controls (C) using the Illumina 850K MethylationEPIC array was integrated with small RNA sequencing-based miRNA quantification to identify miRNA-associated differentially methylated probes (DMPs), link methylation to miRNA expression, and infer downstream targets and pathways. RESULTS: Differential methylation analysis (P ≤ 0.05) revealed 139 miRNA-linked DMPs in C vs. MDD+/-S, 135 in C vs. MDD-S, 179 in C vs. MDD+S, and the highest in MDD+S vs. MDD-S (235). CpG-miRNA pairing (within 1500kb promoter) followed by Spearman correlation identified inverse associations between CpG β values and miRNA expression, with the most consistent signals in suicide-status-stratified subsets, including cg06341821-hsa-miR-574-3p and cg25451306-hsa-miR-2110 in MDD+S-related contrasts, and cg06179179-hsa-miR-595 in MDD-S-related contrasts. High-confidence target prediction and ClueGO enrichment indicated distinct biology: miR-595 target genes in MDD-S were enriched for interferon/innate immune signaling, whereas miR-2110 target genes in MDD+S were enriched for ligand-gated ion channel activity and synaptic/receptor signaling. CONCLUSION: This integrated approach identifies methylation-regulated miRNA pathways that may play key roles in the molecular pathogenesis of MDD and suicide.

Humans↗

PubMed2025

Stress-induced altered expression of hippocampal nuclear and mitochondrial encoded genes in rats and cross-species genetic associations reveal molecular links to depression.

BACKGROUND: Mitochondria play a pivotal role in energy production, and their dysfunction not only hampers cells' ability to meet energy requirements but also contributes to the impairment of neural plasticity, a critical feature of depressive disorders. In this study, mitochondrial cross-omics analysis was carried out in the hippocampus of restraint rats to understand the role of mitochondria in depression pathophysiology. METHODS: The expression profiles of hippocampal mitochondrial and nuclear-encoded genes in mitochondrial fractions from restraint and handled control rats were obtained using high-throughput RNA sequencing. Weighted gene co-expression network analysis (WGCNA) was used to identify the gene co-expression and pathways associated with the restraint phenotype. Mutual Information Network algorithm tools Arance, CLR, and MRNET were additionally used to screen the functional modules and hub genes and their similarity with the WGCNA-based network analysis. Finally, cross-species homology followed by gene association analysis was conducted to obtain SNPs and haplotypes related to depression phenotype. RESULTS: A significant proportion of mitochondrial and nuclear-encoded genes showed differential regulation in the hippocampus of restraint rats. WGCNA and Mutual Information Network analysis yielded distinct functional modules significantly related to restraint phenotype. Further network analysis revealed distinct co-expression patterns associated with differentially expressed genes associated with these modules. Cross-species analysis showed 39 significantly associated SNPs with the depression phenotype, where the most significant SNP, rs10899570, was located within the TENM4 gene. Further, rs1573529 and rs10899570 were distributed into the linkage disequilibrium block where SNPs were highly correlated. Subsequent haplotype analysis showed that rs1573529 and rs10899570 were significantly associated with depressive behavior. CONCLUSIONS: The study demonstrates a significant impact of restraint stress on mitochondrial functions and genetic association, suggesting their critical role in depression pathophysiology.

Animals↗