Phylogeny and chemistry of biological mineral transport

• Published in: Bone (New York, N.Y.) Vol. 141; p. 115621
• Main Authors: Schlesinger, Paul H., Braddock, Demetrios T., Larrouture, Quitterie C., Ray, Evan C., Riazanski, Vladimir, Nelson, Deborah J., Tourkova, Irina L., Blair, Harry C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2020
• Subjects: Acid transport; Bone mineral; Calcium transport; Hydroxyapatite; Osteoblast; Phosphate transport; Osteoblast; Acid transport; Hydroxyapatite; Calcium transport; Bone mineral; Phosphate transport
• ISSN: 8756-3282; 1873-2763
• DOI: 10.1016/j.bone.2020.115621

Three physiologically mineralizing tissues — teeth, cartilage and bone — have critical common elements and important evolutionary relationships. Phylogenetically the most ancient densely mineralized tissue is teeth. In jawless fishes without skeletons, tooth formation included epithelial transport of phosphates, a process echoed later in bone physiology. Cartilage and mineralized cartilage are skeletal elements separate from bone, but with metabolic features common to bone. Cartilage mineralization is coordinated with high expression of tissue nonspecific alkaline phosphatase and PHOSPHO1 to harvest available phosphate esters and support mineralization of collagen secreted locally. Mineralization in true bone results from stochastic nucleation of hydroxyapatite crystals within the cross-linked collagen fibrils. Mineral accumulation in dense collagen is, at least in major part, mediated by amorphous aggregates — often called Posner clusters — of calcium and phosphate that are small enough to diffuse into collagen fibrils. Mineral accumulation in membrane vesicles is widely suggested, but does not correlate with a definitive stage of mineralization. Conversely mineral deposition at non-physiologic sites where calcium and phosphate are adequate has been shown to be regulated in large part by pyrophosphate. All of these elements are present in vertebrate bone metabolism. A key biological element of bone formation is an epithelial-like cellular organization which allows control of phosphate, calcium and pH during mineralization. [Display omitted] •Teeth, the ancestral densely mineralized tissue, are made by epithelial cells.•Cartilage is avascular; its transition to bone includes vascular ingrowth.•Pyrophosphate production prevents mineral in normally non-mineralized tissues.•Epithelial-like cells transport phosphate into and acid out of bone matrix.