Aryl Hydrocarbon Receptor Activation Suppresses EBF1 and PAX5 and Impairs Human B Lymphopoiesis

Abstract

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates biological responses to endogenous and environmental chemical cues. Increasing evidence shows that the AHR plays physiological roles in regulating development, homeostasis and function of a variety of cell lineages in the immune system. However, the role of AHR in human B cell development has not been investigated. Toward this end, an in vitro feeder-free human B cell developmental model system was employed using human cord blood CD34+ hematopoietic stem/progenitor cells (HSPC). Using this model, we found that AHR activation by the high affinity ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), significantly suppressed the generation of early-B cells and pro-B cells from HSPCs, indicating the impairment of B cell lineage specification and commitment. Addition of an AHR antagonist reversed TCDD-elicited suppression of early-B and pro-B cells, suggesting a role of AHR in regulating B lymphopoiesis. Gene expression analysis revealed a significant decrease in the mRNA level of EBF1 and PAX5, two critical transcription factors directing B cell lineage specification and commitment. In addition, binding of the ligand-activated AHR to the putative dioxin response elements in the EBF1 promoter was demonstrated by electrophoretic mobility shift assays and chromatin immunoprecipitation analysis, suggesting transcriptional regulation of EBF1 by AHR. Taken together, this study demonstrates a role for the AHR in regulating human B cell development, and suggests that transcriptional alterations of EBF1 by the AHR are involved in the underlying mechanism.

AHR Signaling Dampens Inflammatory Signature in Neonatal Skin γδ T Cells

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The Role of the Aryl Hydrocarbon Receptor (AhR) in the Immune Response against Microbial Infections

“…Meanwhile, AhR induction inhibits the formation of early B cells and pro-B cells. AhR controls B cell differentiation by transcriptionally suppressing the early B cell genes EBF1 and PAX5 [121].…”

Experimental autoimmune encephalomyelitis in the common marmoset: a translationally relevant model for the cause and course of multiple sclerosis

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