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Plasmodium falciparum malaria drives epigenetic reprogramming of human monocytes toward a regulatory phenotype.

Abstract

In malaria-naive children and adults, Plasmodium falciparum-infected red blood cells (Pf-iRBCs) trigger fever and other symptoms of systemic inflammation. However, in endemic areas where individuals experience repeated Pf infections over many years, the risk of Pf-iRBC-triggered inflammatory symptoms decreases with cumulative Pf exposure. The molecular mechanisms underlying these clinical observations remain unclear. Age-stratified analyses of uninfected, asymptomatic Malian individuals before the malaria season revealed that monocytes of adults produced lower levels of inflammatory cytokines (IL-1beta, IL-6 and TNF) in response to Pf-iRBC stimulation compared to monocytes of Malian children and malaria-naive U.S. adults. Moreover, monocytes of Malian children produced lower levels of IL-1beta and IL-6 following Pf-iRBC stimulation compared to 4-6-month-old infants. Accordingly, monocytes of Malian adults produced more IL-10 and expressed higher levels of the regulatory molecules CD163, CD206, Arginase-1 and TGM2. These observations were recapitulated in an in vitro system of monocyte to macrophage differentiation wherein macrophages re-exposed to Pf-iRBCs exhibited attenuated inflammatory cytokine responses and a corresponding decrease in the epigenetic marker of active gene transcription, H3K4me3, at inflammatory cytokine gene loci. Together these data indicate that Pf induces epigenetic reprogramming of monocytes/macrophages toward a regulatory phenotype that attenuates inflammatory responses during subsequent Pf exposure. Trial Registration: ClinicalTrials.gov NCT01322581.

Authors: Guha R, Mathioudaki A, Doumbo S, Doumtabe D, Skinner J, Arora G, Siddiqui S, Li S, Kayentao K, Ongoiba A, Zaugg J, Traore B, Crompton PD,
Journal: PLoS Pathog; 2021 Apr ; 17 (4) 1009430. doi:10.1371/journal.ppat.1009430
Year: 2021
PubMed: PMID: 33822828 (Go to PubMed)