Aims: This study was designed to determine whether the use of acetylcholinesterase inhibitors (AChEIs), a group of drugs that stimulate Acetylcholine receptors and used to treat Alzheimer’s disease, is associated with osteoporosis protection and inhibition of osteoclast differentiation and function.
Methods: We examined the effects of AChEI on RANKL-induced osteoclast differentiation and function with osteoclastogenesis and bone resorption assays. Next, we investigated impacts of AChEIs on RANKL-induced NF-κB and NFATc1 activation and expression of osteoclast marker genes of CA-2, CTSK and NFATc1, and dissected the MAPK signalling in osteoclasts in vitro by using luciferase assay and Western Blotting. Finally, we assessed the in vivo efficacy of AChEIs using an ovariectomy -induced osteoporosis model, which was analysed using micro-computed tomography, in vivo osteoclast and osteoblast parameters were assessed using bone histomorphometry.
Results: We found that Donepezil and Rivastigmine inhibited RANKL-induced osteoclastogenesis and impaired osteoclastic activity and bone resorption. Moreover, AChEIs reduced the RANKL-induced transcription of NFATc1, and expression of osteoclast marker genes to varying degrees (mainly Donepezil and Rivastigmine but not Galantamine). Furthermore, AChEIs variably inhibited RANKL-indued MAPK signalling. Finally, AChEIs protected against OVX-induced bone loss mainly by inhibiting osteoclast activity.
Conclusions: AChEIs (mainly Donepezil and Rivastigmine) exerted powerful effect on bone protection by inhibiting osteoclast function through MAPK signalling pathway. Our findings will influence drug choice in those patients with both Alzheimer’s disease and osteoporosis.