title: T cells, osteoblasts, and osteocytes: interacting lineages key for the bone anabolic and catabolic activities of parathyroid hormone.
abstract: Osteoimmunology is a field of research dedicated to the study of the interactions between the immune system and bone. Among the cells of the immune system that regulate bone turnover and the responsiveness of bone cells to calciothropic hormones are bone marrow T lymphocytes. T cells secrete osteoclastogenic cytokines such as RANKL and TNF-α, as well as factors that stimulate bone formation, one of which is Wnt10b. In addition, T cells regulate the differentiation and life span of stromal cells (SCs) and their responsiveness to parathyroid hormone (PTH) via costimulatory molecules expressed on their surface. The conditioning effect of T cells on SCs is inherited by the osteoblastic and osteocytic progeny of SCs. As a result, osteoblastic cells of T cell-deficient mice have functional characteristics different from corresponding cells of T cell-replete mice. These differences include the ratio of RANKL/OPG produced in response to continuous PTH treatment, and the osteoblastogenic response to intermittent PTH treatment. This article reviews the evidence indicating that the effects of PTH are mediated not only by osteoblasts and osteocytes but also by T cells.
authors.affiliation: Division of Endocrinology, Metabolism and Lipids, Department of Medicine, and Immunology and Molecular Pathogenesis Program, Emory University, Atlanta, Georgia.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pacifici
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D016723:Bone Remodeling; D001842:Bone and Bones / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002450:Cell Communication; D019070:Cell Lineage; D016207:Cytokines / Q000378:metabolism; D005819:Genetic Markers; D006801:Humans; D008954:Models, Biological; D010006:Osteoblasts / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D010011:Osteocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000276:immunology / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019485:Bone Morphogenetic Proteins; D016207:Cytokines; D005819:Genetic Markers; C470125:PTH protein, human; D010281:Parathyroid Hormone; D011518:Proto-Oncogene Proteins; C422903:SOST protein, human; C491119:WNT10B protein, human; D051153:Wnt Proteins
keywords: PTH; Pacifici, R. 2015. T cells, osteoblasts, and osteocytes: interacting lineages key for the bone anabolic and catabolic activities of parathyroid hormone. In “MARROW,” ed. by M. Zaidi. Ann. N.Y. Acad. Sci. 1364: 11-24.; T cells; bone; osteoblasts; osteocytes; stromal cells