Maintenance of mitochondrial DNA copy number is essential for osteoclast survival

Excerpt

There is accumulating evidence that osteoclasts, the primary cells responsible for bone resorption, are involved in bone and joint destruction in rheumatoid arthritis. Bone resorption is highly regulated by mature osteoclast function as well as osteoclastogenesis. The life span of mature osteoclasts is relatively short both in vitro and in vivo, and once differentiated, they rapidly die in the absence of supporting cell or growth factors. Mitochondria is known as powerhouse of cell because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, cell growth, and cell death. Transcription and replication of mitochondrial DNA (mtDNA) are important steps in mitochondrial biogenesis and mitochondrial transcription factor A (Tfam) is essential for mtDNA transcription and replication. However, the functional significance of mitochondria has not been established in osteoclastic bone resorption. …