Monocyte mitochondrial dysfunction, inflammaging, and inflammatory pyroptosis in major depression.

Area of Science:

• Immunology
• Neuroscience
• Genetics

Background:

• The macrophage theory of depression posits a significant role for macrophages in Major Depressive Disorder (MDD).
• Monocytes serve as precursors to macrophages and microglia, crucial immune cells in the central nervous system.

Purpose of the Study:

• To investigate gene expression patterns in monocytes of MDD patients and healthy controls.
• To correlate gene expression with inflammation markers and clinical parameters in MDD.

Main Methods:

• A cross-sectional study involving 140 MDD patients and 120 healthy controls.
• Analysis of apoptosis/growth and lipid/cholesterol pathway gene expression in monocytes.
• Correlation of gene expression with inflammation-regulating genes and clinical data.

Main Results:

• MDD monocytes exhibited overexpression of apoptosis/growth/cholesterol and TNF genes (cluster 3).
• This cluster 3 upregulation was a common feature across all MDD patients.
• Patients with childhood adversity showed additional upregulation of IL-1/IL-6 clusters and downregulation of the MVK gene.

Conclusions:

• Upregulation of cluster 3 genes suggests premature aging (mitochondrial dysfunction, TNF "inflammaging") in MDD monocytes.
• In patients with childhood adversity, additional inflammation (pyroptosis) and MVK downregulation indicate a more severe inflammatory state.