Oral administration of Flavonifractor plautii attenuates inflammatory responses in obese adipose tissue

Adipose tissue inflammation enhances the symptoms of metabolic syndrome.Flavonifractor plautii, a bacterium present in human feces, has been reported to participate in the metabolism of catechin in the gut. The precise function ofF. plautiiremains unclear. We assessed the immunoregulatory function ofF. plautiiboth in vitro and in vivo. In vitro, we showed that both viable and heat-killedF. plautiiattenuatedTNF-alpha transcript accumulation in lipopolysaccharide-stimulated RAW 264.7 cells. For the in vivo experiment, male C57BL/6 were placed on a high-fat diet (HFD) for 11 weeks. During the final two weeks on the HFD, the animals were administered withF. plautiiby once-daily oral gavage. The oral administration ofF. plautiiattenuated the increase inTNF-alpha transcription otherwise seen in the epididymal adipose tissue of HFD-fed obese mice (HFD + F. plautii). The composition of the microbial population (at the genus level) in the cecal contents of the HFD + F. plautiimice was altered considerably. In particular, the level ofSphingobiumwas decreased significantly, and that ofLachnospiraceaewas increased significantly, in the HFD + F. plautiigroup. Obesity is closely associated with the development of inflammation in adipose tissue.F. plautiimay be involved in inhibition of TNF-alpha expression in inflammatory environments. Our results demonstrated thatF. plautiimay be useful for alleviating the inflammatory responses of adipose tissue.