Sex steroid deficiency-associated bone loss is microbiota dependent and prevented by probiotics

• Authors: Jau-Yi Li, Emory University; Benoit Chassaing, Georgia State University; Abdul Malik Tyagi, Emory University; Chiara Vaccaro, Emory University; Tao Luo, Emory University; Jonathan Adams, Emory University; Trevor M. Darby, Emory University; M. Neale Weitzmann, Emory University; Jennifer G. Mulle, Emory University; Andrew Gewirtz, Emory University; Rheinallt Jones, Emory University; Roberto Pacifici, Emory University
• Journal Title: Journal of Clinical Investigation
• Volume: Volume 126, Number 6
• Publisher: American Society for Clinical Investigation | 2016-06-01, Pages 2049-2063
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1172/JCI86062
• Subjects: Health Sciences, Epidemiology; Health Sciences, General
• Keywords: Science & Technology; Life Sciences & Biomedicine; Medicine, Research & Experimental; Research & Experimental Medicine; BLOOD MONONUCLEAR-CELLS; EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS; INTERMITTENT PTH TREATMENT; EARLY POSTMENOPAUSAL WOMEN; ESTROGEN-RECEPTOR-ALPHA; LOSS IN-VIVO; TNF-ALPHA; T-CELLS; GUT MICROBIOTA; INTESTINAL PERMEABILITY

Abstract

A eubiotic microbiota influences many physiological processes in the metazoan host, including development and intestinal homeostasis. Here, we have shown that the intestinal microbiota modulates inflammatory responses caused by sex steroid deficiency, leading to trabecular bone loss. In murine models, sex steroid deficiency increased gut permeability, expanded Th17 cells, and upregulated the osteoclastogenic cytokines TNFα (TNF), RANKL, and IL-17 in the small intestine and the BM. In germ-free (GF) mice, sex steroid deficiency failed to increase osteoclastogenic cytokine production, stimulate bone resorption, and cause trabecular bone loss, demonstrating that the gut microbiota is central in sex steroid deficiency-induced trabecular bone loss. Furthermore, we demonstrated that twice-weekly treatment of sex steroid-deficient mice with the probiotics Lactobacillus rhamnosus GG (LGG) or the commercially available probiotic supplement VSL#3 reduces gut permeability, dampens intestinal and BM inflammation, and completely protects against bone loss. In contrast, supplementation with a nonprobiotic strain of E. coli or a mutant LGG was not protective. Together, these data highlight the role that the gut luminal microbiota and increased gut permeability play in triggering inflammatory pathways that are critical for inducing bone loss in sex steroid-deficient mice. Our data further suggest that probiotics that decrease gut permeability have potential as a therapeutic strategy for postmenopausal osteoporosis.