title: Faecalibacterium prausnitzii subspecies-level dysbiosis in the human gut microbiome underlying atopic dermatitis.
abstract: BACKGROUND
  Atopic dermatitis (AD) is a serious global epidemic associated with a modern lifestyle.
  
  
  OBJECTIVE
  Although aberrant interactions between gut microbes and the intestinal immune system have been implicated in this skin disease, the nature of the microbiome dysfunction underlying the disease remains unclear.
  
  
  METHODS
  The gut microbiome from 132 subjects, including 90 patients with AD, was analyzed by using 16S rRNA gene and metagenome sequence analyses. Reference genomes from the Human Microbiome Project and the KEGG Orthology database were used for metagenome analyses. Short-chain fatty acids in fecal samples were compared by using gas chromatographic-mass spectrometric analyses.
  
  
  RESULTS
  We show that enrichment of a subspecies of the major gut species Faecalibacterium prausnitzii is strongly associated with AD. In addition, the AD microbiome was enriched in genes encoding the use of various nutrients that could be released from damaged gut epithelium, reflecting a bloom of auxotrophic bacteria. Fecal samples from patients with AD showed decreased levels of butyrate and propionate, which have anti-inflammatory effects. This is likely a consequence of an intraspecies compositional change in F prausnitzii that reduces the number of high butyrate and propionate producers, including those related to the strain A2-165, a lack of which has been implicated in patients with Crohn disease.
  
  
  CONCLUSIONS
  The data suggest that feedback interactions between dysbiosis in F prausnitzii and dysregulation of gut epithelial inflammation might underlie the chronic progression of AD by resulting in impairment of the gut epithelial barrier, which ultimately leads to aberrant TH2-type immune responses to allergens in the skin.
authors.affiliation: Department of Biomedical Sciences, Korea University, Seoul, Korea.
authors.forename: Han
authors.initials: H
authors.lastname: Song
authors.affiliation: Department of Pediatrics, Korea University, Seoul, Korea.
authors.forename: Young
authors.initials: Y
authors.lastname: Yoo
authors.affiliation: Department of Biomedical Sciences, Korea University, Seoul, Korea.
authors.forename: Junghyun
authors.initials: J
authors.lastname: Hwang
authors.affiliation: Western Seoul Center, Korea Basic Science Institute, Seoul, Korea.
authors.forename: Yun-Cheol
authors.initials: YC
authors.lastname: Na
authors.affiliation: Department of Biomedical Sciences, Korea University, Seoul, Korea. Electronic address: hstanleykim@korea.ac.kr.
authors.forename: Heenam Stanley
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000068016:Eubacteriales / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods; D003876:Dermatitis, Atopic / Q000209:etiology*; D064806:Dysbiosis; D005243:Feces / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome; D006801:Humans; D008297:Male; D054892:Metagenome; D056186:Metagenomics; D008954:Models, Biological; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Atopic dermatitis; Faecalibacterium prausnitzii; dysbiosis; gut microbiota; microbiome