Microglia Transcriptional Profiling in Major Depressive Disorder Shows Inhibition of Cortical Gray Matter Microglia, 2023, Huitinga et al

Microglia Transcriptional Profiling in Major Depressive Disorder Shows Inhibition of Cortical Gray Matter Microglia
https://www.biologicalpsychiatryjournal.com/article/S0006-3223(23)01239-8/fulltext
Biological psychiatry

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.

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.

 

I put this in the "related to ME/CFS" forum because, well, most doctors believe that we are all depressed. Doesn't mean the relation is correct, but it this is what they believe and act on.

There really needs to be a more generic term. Inflammation is a form of immune reaction, so is immune suppression. But inflammation is usually used as a short-hand for something involving the immune system, so there are big issues with basic vocabulary here.

 

Interesting paper. So they found differences in the grey but not the white matter and these differences indicated immune-suppressed microglia rather than immune-activated microglia.

These researchers have now received funding to collect and study post-mortem brain samples of ME/CFS (EDIT: as part of the Dutch ME/CFS research program).