Bang Corinna, Vierbuchen Tim, Gutsmann Thomas, Heine Holger, Schmitz Ruth A
Institute for General Microbiology, Christian-Albrechts-University Kiel, Kiel, Germany.
Division of Innate Immunity, Research Center Borstel, Airway Research Center North, Member of the German Center for Lung Research (DZL), Borstel, Germany.
PLoS One. 2017 Oct 5;12(10):e0185919. doi: 10.1371/journal.pone.0185919. eCollection 2017.
The methanogenic archaeon Methanomassiliicoccus luminyensis strain B10T was isolated from human feces just a few years ago. Due to its remarkable metabolic properties, particularly the degradation of trimethylamines, this strain was supposed to be used as "Archaebiotic" during metabolic disorders of the human intestine. However, there is still no data published regarding adaptations to the natural habitat of M. luminyensis as it has been shown for the other two reported mucosa-associated methanoarchaea. This study aimed at unraveling susceptibility of M. luminyensis to antimicrobial peptides as well as its immunogenicity. By using the established microtiter plate assay adapted to the anaerobic growth requirements of methanogenic archaea, we demonstrated that M. luminyensis is highly sensitive against LL32, a derivative of human cathelicidin (MIC = 2 μM). However, the strain was highly resistant against the porcine lysin NK-2 (MIC = 10 μM) and the synthetic antilipopolysaccharide peptide (Lpep) (MIC>10 μM) and overall differed from the two other methanoarchaea, Methanobrevibacter smithii and Methanosphaera stadtmanae in respect to AMP sensitivity. Moreover, only weak immunogenic potential of M. luminyensis was demonstrated using peripheral blood mononuclear cells (PBMCs) and monocyte-derived dendritic cells (moDCs) by determining release of pro-inflammatory cytokines. Overall, our findings clearly demonstrate that the archaeal gut inhabitant M. luminyensis is susceptible to the release of human-derived antimicrobial peptides and exhibits low immunogenicity towards human immune cells in vitro-revealing characteristics of a typical commensal gut microbe.
产甲烷古菌鲁米尼产甲烷球形菌B10T菌株是几年前从人类粪便中分离出来的。由于其显著的代谢特性，特别是三甲胺的降解能力，该菌株被认为可在人类肠道代谢紊乱期间用作“古生物制剂”。然而，与另外两种已报道的与黏膜相关的产甲烷古菌不同，目前仍没有关于鲁米尼产甲烷球形菌对其自然栖息地适应性的相关数据发表。本研究旨在揭示鲁米尼产甲烷球形菌对抗菌肽的敏感性及其免疫原性。通过使用适应产甲烷古菌厌氧生长需求的既定微量滴定板测定法，我们证明鲁米尼产甲烷球形菌对人cathelicidin的衍生物LL32高度敏感（MIC = 2 μM）。然而，该菌株对猪溶素NK-2（MIC = 10 μM）和合成抗脂多糖肽（Lpep）（MIC>10 μM）具有高度抗性，并且在AMP敏感性方面总体上与另外两种产甲烷古菌，即史氏甲烷短杆菌和施氏甲烷球形菌不同。此外，通过测定促炎细胞因子的释放，使用外周血单核细胞（PBMC）和单核细胞衍生的树突状细胞（moDC）仅证明鲁米尼产甲烷球形菌具有较弱的免疫原性。总体而言，我们的研究结果清楚地表明，肠道古菌鲁米尼产甲烷球形菌易受人类衍生的抗菌肽释放的影响，并且在体外对人类免疫细胞表现出低免疫原性，揭示了典型共生肠道微生物的特征。
