Women gradually lose bone from the age of〜35 years,but around menopause,the rate of bone loss escalates due to increasing bone resorption and decreasing bone formation levels,rendering these individuals more prone to ...Women gradually lose bone from the age of〜35 years,but around menopause,the rate of bone loss escalates due to increasing bone resorption and decreasing bone formation levels,rendering these individuals more prone to developing osteoporosis.The increased osteoclast activity has been linked to a reduced estrogen level and other hormonal changes.However,it is unclear whether intrinsic changes in osteoclast precursors around menopause can also explain the increased osteoclast activity.Therefore,we set up a protocol in which CD14f blood monocytes were isolated from 49 female donors(40-66 years old).Cells were differentiated into osteoclasts,and data on differentiation and resorption activity were collected.Using multiple linear regression analyses combining in vitro and in vivo data,we found the following:(1)age and menopausal status correlate with aggressive osteoclastic bone resorption in vitro;(2)the type I procollagen N-terminal propeptide level in vivo inversely correlates with osteoclast resorption activity in vitro;(3)the protein level of mature cathepsin K in osteoclasts in vitro increases with age and menopause;and(4)the promoter of the gene encoding the dendritic cell-specific transmembrane protein is less methylated with age.We conclude that monocytes are"reprogrammed"in vivo,allowing them to"remember"age,the menopausal status,and the bone formation status in vitro,resulting in more aggressive osteoclasts.Our discovery suggests that this may be mediated through DNA methylation.We suggest that this may have clinical implications and could contribute to understanding individual differences in age-and menopause-induced bone loss.展开更多
基金This study was financed by the Research Counsel of Lillebaelt Hospitalthe Region of Southern Denmark(15/24819)+3 种基金the Institute of Regional Health Research,University of Southern Denmarkthe Aase Ejnar Danielsen foundation(10-001835)the Fru Astrid Thaysens foundation(ATL 16/02)We particularly wish to thank Annette Ulv for her hard work recruiting the blood donors,Merete Villumsen for her excellent technical assistance on CTX and PINP measurements,and Hellen Kuasne for her kind support in primer selection for pyrosequencing.
文摘Women gradually lose bone from the age of〜35 years,but around menopause,the rate of bone loss escalates due to increasing bone resorption and decreasing bone formation levels,rendering these individuals more prone to developing osteoporosis.The increased osteoclast activity has been linked to a reduced estrogen level and other hormonal changes.However,it is unclear whether intrinsic changes in osteoclast precursors around menopause can also explain the increased osteoclast activity.Therefore,we set up a protocol in which CD14f blood monocytes were isolated from 49 female donors(40-66 years old).Cells were differentiated into osteoclasts,and data on differentiation and resorption activity were collected.Using multiple linear regression analyses combining in vitro and in vivo data,we found the following:(1)age and menopausal status correlate with aggressive osteoclastic bone resorption in vitro;(2)the type I procollagen N-terminal propeptide level in vivo inversely correlates with osteoclast resorption activity in vitro;(3)the protein level of mature cathepsin K in osteoclasts in vitro increases with age and menopause;and(4)the promoter of the gene encoding the dendritic cell-specific transmembrane protein is less methylated with age.We conclude that monocytes are"reprogrammed"in vivo,allowing them to"remember"age,the menopausal status,and the bone formation status in vitro,resulting in more aggressive osteoclasts.Our discovery suggests that this may be mediated through DNA methylation.We suggest that this may have clinical implications and could contribute to understanding individual differences in age-and menopause-induced bone loss.
