Bone Marrow Microenvironmental Diversity in Skeletal Remodeling, Aging, and Infectious Disease

Highly specialized bone marrow microenvironments govern bone remodeling by modulating the activity of osteoblasts, osteoclasts, stromal populations, immune cells, vascular niches, hematopoietic stem cells, and marrow adipocytes. Emerging evidence demonstrates that these microenvironments exhibit profound spatial, cellular, and functional heterogeneity throughout the skeleton — and that the extra-intestinal microbiome is a critical, underappreciated regulator of this niche diversity. Microbial communities at extra-intestinal sites, including the oral cavity, urinary tract, respiratory tract, and systemic circulation, can influence skeletal homeostasis through immune reprogramming, microbial metabolite signalling, and direct pathogen-marrow interactions.Recent advances in single-cell transcriptomics, spatial omics, multiplex imaging, lineage tracing, and systems biology have transformed our understanding of the marrow niche as a dynamic and regionally specialized ecosystem shaped not only by local skeletal signals but also by systemic microbial and infectious cues. Dysbiosis, chronic infection, and pathogen dissemination — including osteomyelitis, septicaemia, and haematogenous spread — can profoundly reshape marrow microenvironments in ways that alter skeletal remodeling and disease susceptibility. Aging, sex, inflammation, metabolic disease, and mechanical loading further interact with microbial signals to compound niche remodeling.This Research Topic seeks original research articles, reviews, mini-reviews, perspectives, and methodological papers focused on the diversity of bone marrow microenvironments and their roles in skeletal remodeling across physiological and pathological contexts, with particular emphasis on the contribution of the extra-intestinal microbiome and infectious disease. We particularly encourage submissions integrating osteoimmunology, spatial biology, skeletal aging, marrow adiposity, host-pathogen interactions, and translational human studies.We welcome papers addressing the following themes, including but not limited to:-Bone marrow microenvironments as highly specialized niches regulated through coordinated interactions among osteoblasts, osteoclasts, immune cells, stromal populations, vascular niches, hematopoietic stem cells, and marrow adipocytes-The extra-intestinal microbiome — encompassing oral, urinary, respiratory, and circulatory microbial communities — as a systemic modulator of bone marrow niche composition and function-Microbial metabolites (SCFAs, urolithins, bile acid derivatives) and their roles in osteoblast-osteoclast balance and marrow niche regulation-Direct pathogen engagement with the bone marrow microenvironment, including osteomyelitis, haematogenous infection, and septic arthritis-Dysbiosis-driven immune reprogramming and its downstream effects on skeletal remodeling and marrow adiposity-Spatial, cellular, and functional heterogeneity of marrow niches across skeletal sites — vertebrae, long bones, calvaria, trabecular versus cortical compartments — and how microbial signals differentially affect these regions-Single-cell transcriptomics, spatial omics, multiplex imaging, lineage tracing, and systems biology approaches to map microbial influence on the marrow niche-Physiological and pathological factors — aging, sex, inflammation, metabolic disease, mechanical loading, and immune dysregulation — interacting with microbial cues to reshape marrow microenvironments-Translational human studies bridging bench findings on host-microbiome-bone interactions to clinical skeletal pathology-The overarching goal is to map how microenvironmental diversity across the skeleton, shaped by extra-intestinal microbial and infectious disease contexts, governs bone health and disease across the lifespan Topic editors: Elizabeth W Bradley, Roman Thaler Source: https://www.frontiersin.org/research-topics/82504/bone-marrow-microenvironmental-diversity-in-skeletal-remodeling-aging-and-infectious-disease