Download Bellido, Teresita - The Cells of Bone

Endocrine Fellows Forum, Atlanta 2016
The Bone Cells: Osteoclasts, Osteoblasts and Osteocytes. Where they
derive from and how they communicate with each other?
Teresita Bellido, Ph.D.
Professor of Anatomy and Cell Biology
Professor of Medicine, Division of Endocrinology
Indiana University School of Medicine
Senior Research Scientist, VA Medical Center
Indianapolis, Indiana, USA
Bone development and the adaptation of the adult skeleton to mechanical needs and
hormonal changes depend on the ability of bone cells to resorb and form bone in the
right places and at the right time. Bone growth, modeling or remodeling are defined by
the spatial and temporal relationship between bone resorption and bone formation.
Osteoclasts resorb bone, osteoblasts form bone, and osteocytes detect the need for
bone augmentation or reduction and coordinate the activity of osteoclasts and
osteoblasts. Osteoclasts are the primary bone-resorptive cells and originate from
precursors of the hematopoietic lineage upon stimulation with receptor activator of NFκB ligand (RANKL) and macrophage colony-stimulating factor (MCSF). The rate of
osteoclast generation determines the extension of the bone multicellular unit (BMU),
whereas the life span of osteoclasts determines the depth of resorption. Osteoblasts are
the cells responsible for bone formation and originate from mesenchymal progenitors
that also give rise to chondrocytes, muscle cells, and adipocytes. Osteocytes are former
osteoblasts that remain within the mineralized bone matrix and form a network that
senses mechanical and hormonal environmental cues and orchestrates the function of
osteoblasts and osteoclasts. This presentation will discuss the current knowledge on
generation, fate and function of bone cells.