V-ATPase and Lysosomal Energy Sensing in Periodontitis and Medicine-Related Osteonecrosis of the Jaw.

Diabetes is a risk factor for periodontitis. Increasing evidence suggests that a central player in this link is the vacuolar H+-ATPase (V-ATPase), which provides a physical and functional core for regulation by the catabolic lysosomal AMP-activated protein kinase complex (L-AMPK) and the anabolic mammalian target of rapamycin complex 1 (mTORC1). These complexes detect levels of various cellular nutrients, including glucose at the lysosome, and promote cellular responses to restore homeostasis. The high-glucose conditions of diabetes foster anabolic mTORC1 signaling that increases inflammation and inflammatory bone resorption in response to periodontal infections. Here, we review the structure and composition of V-ATPase, L-AMPK, mTORC1, and other elements of the energy-sensing platform. Mechanisms by which V-ATPase passes signals to the complexes are examined and recent data are reviewed. Current anti-bone resorptive therapeutics, bisphosphonates and denosumab, enhance the risk of medicine-related osteonecrosis of the jaw (MRONJ) and are not used to treat periodontal bone loss. Accumulating data suggest that it may be possible to target inflammatory bone resorption through agents that stimulate L-AMPK, including metformin and glucagon-like peptide-1 agonists. This approach may reduce inflammatory bone resorption without major effects on overall bone remodeling or increased risk of MRONJ.