Methanosphaera stadtmanae induces a type IV hypersensitivity response in a mouse model of airway inflammation

Abstract

Despite improved awareness of work‐related diseases and preventive measures, many workers are still at high risk of developing occupational hypersensitivity airway diseases. This stems from a lack of knowledge of bioaerosol composition and their potential effects on human health. Recently, archaea species were identified in bioaerosols, raising the possibility that they play a major role in exposure‐related pathology. Specifically, Methanosphaera stadtmanae (MSS) and Methanobrevibacter smithii (MBS) are found in high concentrations in agricultural environments and respiratory exposure to crude extract demonstrates immunomodulatory activity in mice. Nevertheless, our knowledge of the specific impact of methanogens exposure on airway immunity and their potential to induce airway hypersensitivity responses in workers remains scant. Analysis of the lung mucosal response to methanogen crude extracts in mice demonstrated that MSS and MBS predominantly induced TH17 airway inflammation, typical of a type IV hypersensitivity response. Furthermore, the response to MSS was associated with antigen‐specific IgG1 and IgG2a production. However, despite the presence of eosinophils after MSS exposure, only a weak TH2 response and no airway hyperresponsiveness were observed. Finally, using eosinophil and mast cell‐deficient mice, we confirmed that these cells are dispensable for the TH17 response to MSS, although eosinophils likely contribute to the exacerbation of inflammatory processes induced by MSS crude extract exposure. We conclude that, as MSS induces a clear type IV hypersensitivity lung response, it has the potential to be harmful to workers frequently exposed to this methanogen, and that preventive measures should be taken to avoid chronic hypersensitivity disease development in workers.

RNA is taking its Toll: Impact of RNA‐specific Toll‐like receptors on health and disease

“…No pathogenic archaeal species has been identified so far, although their potential existence has been discussed for over a decade . However, a role of archaea in inflammatory diseases such as periodontitis, inflammatory bowel disease (IBD), or airway inflammation has been suggested. The methanogenic archaeon Methanosphaera stadtmanae induces strong inflammatory responses in human peripheral blood mononuclear cells (PBMCs) and moDCs .…”

The Human-Associated Archaeon Methanosphaera stadtmanae Is Recognized through Its RNA and Induces TLR8-Dependent NLRP3 Inflammasome Activation

“…Although much research has focused upon bacterial species (which dominate the human gut microbiota), species of the archaeal domain are also stable components of the gut microbiota ( 4 – 6 ). Relatively little is known as to how these less-studied organisms influence human health, although several studies have suggested that methanogenic species of archaea, such as Methanosphaera stadtmanae , might be involved in the development of systemic diseases such as obesity ( 7 – 10 ), cancer ( 11 – 13 ), lung hyperresponsiveness ( 14 ), and inflammatory bowel disease (IBD) ( 15 ). Understanding the molecular mechanisms through which these microorganisms induce inflammation is thus an important step in uncovering how such diseases might develop.…”

Development of an Analytical Method for the Metaproteomic Investigation of Bioaerosol from Work Environments

“…In this metaproteomic work, WWTP bioaerosol was collected on two filters (F1‐F2) in proximity of the oxidation ditches, a tertiary treatment process. The 15 proteins and 17 peptides identified in these samples were ascribed to three domains ( Figure and , Supporting Information); in particular, nine peptide sequences were specific at eukaryote level (five fungal species, i.e., Agaricomycetes , A. fumigatus , C. albicans , Hypocreomycetidae , Saccharomyces ) and three sequences belonged to Viridiplantae kingdom ( Brassicaceae , Streptophytina ); six peptide sequences were specific at bacteria level ( Bacteria , Candidatus Protochlamydia amoebophila , Gammaproteobacteria , Lawsonia intracellularis , Nitrosomonas Rhodobacteraceae ); finally, three peptide sequences were specific at Archea level and attributed to a protein related to the pathogenic microorganism Archaeoglobus fulgidus , a sulfur‐metabolizing organism (identified in F1); a previous study provided evidence of inflammatory potential of some species of Archaea in mice, and possible impact on respiratory health. Therefore, the monitoring of Archea species in bioaerosol is fundamental in order to evaluate the exposure risks.…”