The human body is colonized by an abundant and genetically diverse microbial community, the microbiota. Although the number of our microbial colonizers is one order of magnitude higher than the number of our cells, the number of genes encoded by the human microbiome (the genome of all microbiota) exceeds that encoded by the human genome by 100-fold. The human microbiota is considered a major player in health-related processes, either by direct influence or through interaction with other health determinants, including genetics, diet, lifestyle, medical practices, hygiene and the exposome (the totality of environmental factors humans are exposed to during their lifetime). The rapid rise of several 'omics' techniques and their application in the context of large research initiatives, such as the Human Microbiome Project1 in the USA and MetaHIT2 in Europe, have revolutionized the field by shedding light on correlations between health status and microbiome composition, specific expression of genes, translation into proteins or production of specific metabolites. The influence of the human microbiota on health is being increasingly recognized not to be solely confined to the gut region. For example, whole-genome shotgun data from the Human Microbiome Project has revealed the microbiome to be composed of up to 30% of Clostridium clusters IV and XIVa3, many of which have immune-modulating effects4.
16-06-2016 | Microbiome | Review | Article
How the microbiota shapes rheumatic diseases
Abstract
The human gut harbours a tremendously diverse and abundant microbial community that correlates with, and even modulates, many health-related processes. The mucosal interfaces are particularly active sites of microorganism–host interplay. Growing insight into the characteristic composition and functionality of the mucosal microbiota has revealed that the microbiota is involved in mucosal barrier integrity and immune function. This involvement affects proinflammatory and anti-inflammatory processes not only at the epithelial level, but also at remote sites such as the joints. Here, we review the role of the gut microbiota in shaping local and systemic immune responses and how disturbances in the host–microorganism interplay can potentially affect the development and progression of rheumatic diseases. Increasing our understanding of how to promote host–microorganism homeostasis could therefore reveal novel strategies for the prevention or alleviation of rheumatic disease.
Subject terms: Immunopathogenesis • Microbiota • Rheumatic diseases
Nat Rev Rheumatol 2016;12:398–411. doi:10.1038/nrrheum.2016.85