Epigenetic and metabolic reprogramming support plasma cell differentiation in germinal centers

Area of Science:

• Immunology
• Epigenetics
• Cellular Metabolism

Background:

• The germinal center (GC) is crucial for high-quality antibody production.
• A pre-plasma cell (prePC) population exists in mouse GC B cells, but their differentiation into plasma cells (PCs) is not fully understood.
• Previous findings in mouse prePCs lack validation in human cells.

Purpose of the Study:

• To investigate the differentiation mechanisms of prePCs into PCs.
• To identify markers for prePCs in both mouse and human systems.
• To explore the role of epigenetic modifications and metabolism in prePC differentiation.

Main Methods:

• Immunohistochemistry to detect CD205 expression in mouse and human GC B cells.
• Analysis of Kdm6b and Kdm6a expression and function in prePC differentiation.
• Assessment of histone modifications, specifically H3K27me3, at the Irf4 locus.
• Metabolic profiling of prePCs, focusing on glutamine metabolism.

Main Results:

• CD205 is highly expressed in prePCs in both mouse and human GCs.
• Kdm6b, but not Kdm6a, significantly promotes prePC differentiation into PCs.
• Kdm6b removes repressive H3K27me3 marks at the Irf4 locus, facilitating PC development.
• PrePCs exhibit a preference for glutamine metabolism, supplying α-ketoglutarate for Kdm6b activity.

Conclusions:

• CD205 serves as a marker for prePCs in both mouse and human germinal centers.
• Kdm6b-mediated epigenetic reprogramming, fueled by glutamine metabolism, is essential for prePC to PC differentiation.
• This study elucidates key molecular and metabolic events driving antibody-producing cell differentiation within the GC.