Oxidative Stress-initiated One-carbon Metabolism drives Interleukin-10-producing B Cells to Resolute Pneumonia (RNA-Seq)

Metabolic reprogramming for regulatory B cell generation in infectious diseases remains unknown. With a Pseudomonas aeruginosa-induced pneumonia model, we report IL-10-producing B cells (IL-10+B cells) are indispensable for spontaneous remission of the infection. The accumulation of cytosolic reactive oxygen species (ROS) is responsible for the IL-10 producing within B cells. Of note, ROS scavenging downregulated the one-carbon metabolism and the depletion of one-carbon metabolic methyl transfer enzyme serine hydroxymethyl transferase 1 (Shmt1) led to decreased IL-10+ B cells production both in vitro and in vivo. Mechanistically, one-carbon flux enhanced the availability of methyl groups, which altered histone H3 lysine 4 methylation at Il10 loci and led to massive IL-10 production in B cells. Therefore, the metabolic-associated drug ethacrynic acid (EA) was screened out and potentially restored infectious pneumonia accompanied by increased IL-10+ B cells. The results provide a new insight that ROS serve as modulators to resolute inflammation by reprogramming one-carbon metabolism in lung B cells. To screen for alterations involved in ROS-dependent IL-10+B cells, the RNA sequencing analyses were carried out. Splenic B cells were isolated and cultured under correspondent stimulations after 24h (αIgM, αIgM+LPS, αIgM+LPS+NAC, n=3) and the unstimulated group were B cells without any stimulation after isolated (n=3). Total RNA was extracted using RNAsimple Total RNA Kit (TIANGEN, China). RNA sequencing was performed by the Beijing Genomics Institute (BGI, Shenzhen, China).