Background: Microglia have been implicated in the pathophysiology of major depressive disorder (MDD), but information on biological mechanisms is limited. Therefore, we investigated the gene expression profile of microglial cells in relation to neuronal regulators of microglia activity in well-characterized MDD and control autopsy brains.
Methods: Pure, intact microglia were isolated at brain autopsy from occipital cortex gray matter (GM) and corpus callosum white matter of 13 donors with MDD and 10 age-matched control donors for RNA sequencing. Top differentially expressed genes were validated using immunohistochemistry staining. Because gene expression changes were only detected in GM microglia, neuronal regulators of microglia were investigated in cortical tissue and synaptosomes from the cortex by reverse transcriptase-quantitative polymerase chain reaction and Western blot.
Results: Transcriptome analysis revealed 92 genes differentially expressed in microglia isolated from GM, but none in microglia from white matter in donors with MDD, compared with control donors. Of these, 81 genes were less abundantly expressed in GM in MDD, including CD163, MKI67, SPP1, CD14, FCGR1A/C, and C1QA/B/C. Accordingly, pathways related to effector mechanisms, such as the complement system and phagocytosis, were differentially regulated in GM microglia in MDD. Immunohistochemistry staining revealed significantly lower expression of CD163 protein in MDD. Whole tissue analysis showed an increase in CD200 (p = .0009) and CD47 (p = .068) messenger RNA, and CD47 protein was significantly elevated (p = .0396) in synaptic fractions of MDD cases.
Conclusions: Transcriptional profiling indicates an immune-suppressed microglial phenotype in MDD that is possibly caused by neuronal regulation.
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http://dx.doi.org/10.1016/j.biopsych.2023.04.020 | DOI Listing |
J Neuroinflammation
January 2025
Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
Background: Traumatic brain injury (TBI) is characterized by high mortality and disability rates. Disease-associated microglia (DAM) are a newly discovered subtype of microglia. However, their presence and function in the acute phase of TBI remain unclear.
View Article and Find Full Text PDFJ Prev Alzheimers Dis
January 2025
School of Health and Biomedical Sciences, RMIT University, 220 3-5 Plenty Road, Bundoora VIC 3082, Australia. Electronic address:
Alzheimer's Disease (AD) is a chronic neurodegenerative disorder characterized by the accumulation of toxic amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFTs) of tau protein in the brain. Microglia, key immune cells of the central nervous system, play an important role in AD development and progression, primarily through their responses to Aβ and NFTs. Initially, microglia can clear Aβ, but in AD, chronic activation overwhelms protective mechanisms, leading to sustained neuroinflammation that enhances plaque toxicity, setting off a damaging cycle that affects neurons, astrocytes, cerebral vasculature, and other microglia.
View Article and Find Full Text PDFJ Nutr
January 2025
USDA-ARS, Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA. Electronic address:
Background: Acute neuroinflammatory and oxidative-stress (OS)-inducing stressors, such as high energy and charge (HZE) particle irradiation, produce accelerated aging in the brain. Anti-inflammatory and antioxidant foods, such as blueberries (BB), attenuate neuronal and cognitive deficits when administered to rodents before or both before and after HZE particle exposure. However, the effects of post-stressor treatments are unknown and may be important to repair initial damage and prevent progressive neurodegeneration.
View Article and Find Full Text PDFExp Neurol
January 2025
Department of Neurosurgery, Faculty of Medicine, Hokkaido University, Sapporo, Japan.
Introduction: Brain damage caused by subarachnoid hemorrhage (SAH) currently lacks effective treatment, leading to stagnation in the improvement of functional outcomes for decades. Recent studies have demonstrated the therapeutic potential of exosomes released from mesenchymal stem cells (MSC), which effectively attenuate neuronal apoptosis and inflammation in neurological diseases. Due to the challenge of systemic dilution associated with intravenous administration, intranasal delivery has emerged as a novel approach for targeting the brain.
View Article and Find Full Text PDFJ Transl Med
January 2025
Division of Spine, Department of Orthopedics, Tongji Hospital affiliated to Tongji University, Tongji University School of Medicine, Shanghai, 200065, China.
Background: Ferroptosis and immune responses are critical pathological events in spinal cord injury (SCI), whereas relative molecular and cellular mechanisms remain unclear.
Methods: Micro-array datasets (GSE45006, GSE69334), RNA sequencing (RNA-seq) dataset (GSE151371), spatial transcriptome datasets (GSE214349, GSE184369), and single cell RNA sequencing (scRNA-seq) datasets (GSE162610, GSE226286) were available from the Gene Expression Omnibus (GEO) database. Through weighted gene co-expression network analysis and differential expression analysis in GSE45006, we identified differentially expressed time- and immune-related genes (DETIRGs) associated with chronic SCI and differentially expressed ferroptosis- and immune-related genes (DEFIRGs), which were validated in GSE151371.
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