Broad-spectrum antibiotics disrupt homeostatic efferocytosis [bulk RNA-seq]

The clearance of apoptotic cells, termed efferocytosis, is essential for tissue homeostasis and prevention of autoimmunity. Although past studies have elucidated local molecular signals that regulate homeostatic efferocytosis1 in a tissue, whether signals arising distally also regulate homeostatic efferocytosis remains elusive. Here, we find that large peritoneal macrophages (LPMs) display impaired efferocytosis in broad-spectrum antibiotics (ABX)-treated, vancomycin-treated, and germ-free mice in vivo. Mechanistically, the microbiota-derived short-chain fatty acid butyrate directly boosted efferocytosis efficiency/capacity in mouse and human macrophages, and rescued ABX-induced LPM efferocytosis defects in vivo. Bulk mRNA sequencing of butyrate-treated macrophages in vitro and single cell mRNA sequencing of LPMs isolated from ABX-treated and butyrate-rescued mice revealed regulation of efferocytosis-supportive transcriptional programs. Specifically, we found that the efferocytosis receptor T-cell immunoglobulin and mucin domain containing 4 (TIM-4, Timd4) was downregulated in LPMs of ABX-treated mice but rescued by oral butyrate and TIM-4 was required for the butyrate-induced enhancement of LPM efferocytosis capacity. LPM efferocytosis was impaired beyond withdrawal of ABX and ABX-treated mice exhibited significantly worse disease in a mouse model of lupus. Our results demonstrate that homeostatic efferocytosis relies on distal metabolic signals and suggest that defective homeostatic efferocytosis may explain link between ABX use and inflammatory disease.