Biophysical Modulation of the Mitochondrial Metabolism and Redox in Bone Homeostasis and Osteoporosis: How Biophysics Converts into Bioenergetics

• Published in: Antioxidants 2021-08, Vol.10 (9), p.1394
• Main Authors: Wang, Feng-Sheng, Wu, Re-Wen, Chen, Yu-Shan, Ko, Jih-Yang, Jahr, Holger, Lian, Wei-Shiung
• Format: Article
• Language: English
• Subjects: Adenosine triphosphate; Antioxidants; Apoptosis; Autophagy; Bioenergetics; biophysical stimulation; Bone density; Bone growth; Bone mass; Bone remodeling; Bone turnover; Bones; Calcium (mitochondrial); Calcium influx; Calcium signalling; Cell differentiation; Cell growth; Dehydrogenases; Electromagnetic fields; Estrogens; Exercise; Extracellular matrix; Fractures; Gene expression; Glycolysis; Growth hormones; Homeostasis; Integrins; Ion channels; Kinases; Mechanical loading; Mechanical stimuli; mechanosensitive; Metabolism; Metabolites; Mitochondria; mitochondria biogenesis; Mitochondrial DNA; Mutation; NAD; osteoblasts; Osteoporosis; Oxidative phosphorylation; Oxidative stress; PGC-1α; Phosphorylation; Physical activity; Physical fitness; Proteins; Respiration; Review; Senescence; Stem cells
• ISSN: 2076-3921; 2076-3921
• DOI: 10.3390/antiox10091394

Bone-forming cells build mineralized microstructure and couple with bone-resorbing cells, harmonizing bone mineral acquisition, and remodeling to maintain bone mass homeostasis. Mitochondrial glycolysis and oxidative phosphorylation pathways together with ROS generation meet the energy requirement for bone-forming cell growth and differentiation, respectively. Moderate mechanical stimulations, such as weight loading, physical activity, ultrasound, vibration, and electromagnetic field stimulation, etc., are advantageous to bone-forming cell activity, promoting bone anabolism to compromise osteoporosis development. A plethora of molecules, including ion channels, integrins, focal adhesion kinases, and myokines, are mechanosensitive and transduce mechanical stimuli into intercellular signaling, regulating growth, mineralized extracellular matrix biosynthesis, and resorption. Mechanical stimulation changes mitochondrial respiration, biogenesis, dynamics, calcium influx, and redox, whereas mechanical disuse induces mitochondrial dysfunction and oxidative stress, which aggravates bone-forming cell apoptosis, senescence, and dysfunction. The control of the mitochondrial biogenesis activator PGC-1α by NAD+-dependent deacetylase sirtuins or myokine FNDC/irisin or repression of oxidative stress by mitochondrial antioxidant Nrf2 modulates the biophysical stimulation for the promotion of bone integrity. This review sheds light onto the roles of mechanosensitive signaling, mitochondrial dynamics, and antioxidants in mediating the anabolic effects of biophysical stimulation to bone tissue and highlights the remedial potential of mitochondrial biogenesis regulators for osteoporosis.