Aging impairs peroxisome biogenesis in human B cells

Area of Science:

• Immunology
• Cell Biology
• Metabolism

Background:

• Cellular metabolism is crucial for immune cell function.
• Peroxisomes are key metabolic organelles, but their role in immune cells is not well understood.
• Animal studies suggest peroxisome biogenesis declines with age, but this is unconfirmed in humans.

Purpose of the Study:

• To investigate peroxisome biogenesis in aging human peripheral blood mononuclear cells (PBMCs).
• To determine if peroxisome function declines with age in specific human immune cell types.

Main Methods:

• Analysis of peroxisome biogenesis markers in human PBMCs from different age groups.
• Quantification of peroxisomal matrix enzyme import and key peroxisome biogenesis proteins (PEX19, PEX2, PEX10, PEX12).
• Comparison of peroxisome biogenesis across different immune cell subsets (B cells, T cells, monocytes).

Main Results:

• A significant decline in peroxisome biogenesis was observed in aged CD19+ B cells compared to other immune cells.
• Aging B cells showed reduced import of peroxisomal matrix enzymes, including SKL-containing enzymes and mature ACOX1.
• Downregulation of peroxisome biogenesis factors (PEX19) and E3 ubiquitin ligases (PEX2, PEX10, PEX12) was noted in aged B cells.

Conclusions:

• Confirms an evolutionarily conserved, age-related decline in peroxisome biogenesis in human immune cells.
• Reveals cell type-specific changes in aging human PBMCs, particularly affecting B cells.
• Provides novel insights into peroxisome-mediated immunometabolism and the aging of B cells.