{"title":"CUL1 exacerbates glucocorticoid-induced osteoporosis by enhancing ASAP1 ubiquitination","authors":"Jun Wu, Weijian Ren, Jun Liu, Xizhuang Bai","doi":"10.1007/s42000-024-00599-y","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Background</h3><p>Glucocorticoid-induced osteoporosis is a leading secondary cause of osteoporosis. Cullin-1 (CUL1) levels are abnormally elevated in patients with osteoporosis, but the underlying mechanism remains unclear. The purpose of this study was to elucidate the mechanism of action of CUL1 in a glucocorticoid (dexamethasone, Dex)-induced osteoporosis model.</p><h3 data-test=\"abstract-sub-heading\">Methods</h3><p>C57BL/6J mice were intraperitoneally injected with Dex to establish an osteoporosis model. Mouse femur bone injury and bone formation were detected using hematoxylin-eosin or Masson staining. Apoptosis and cell cycle distribution were determined by flow cytometry. Alkaline phosphatase (ALP) activity and calcified nodules were monitored using ALP and Alizarin Red S staining. The molecular mechanism was validated by co-immunoprecipitation (Co-IP) and ubiquitination assays.</p><h3 data-test=\"abstract-sub-heading\">Results</h3><p>CUL1 expression was enhanced in the Dex-induced osteoporosis mouse model. CUL1 silencing moderated the Dex-induced cell proliferation and osteogenesis inhibition. Moreover, CUL1 promoted the ubiquitination and degradation of ASAP1 via the SKP1-CUL1-F-box (SCF)-FBXW7 complex. CUL1 induced apoptosis and repressed osteogenesis by ASAP1. CUL1 silencing alleviated the Dex-induced osteoporosis in mice.</p><h3 data-test=\"abstract-sub-heading\">Conclusion</h3><p>CUL1 suppressed osteoblast proliferation and osteogenesis by promoting ASAP1 ubiquitination via the SCF-FBXW7 complex in glucocorticoid-induced osteoporosis.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":13017,"journal":{"name":"Hormones","volume":"35 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hormones","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s42000-024-00599-y","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Background
Glucocorticoid-induced osteoporosis is a leading secondary cause of osteoporosis. Cullin-1 (CUL1) levels are abnormally elevated in patients with osteoporosis, but the underlying mechanism remains unclear. The purpose of this study was to elucidate the mechanism of action of CUL1 in a glucocorticoid (dexamethasone, Dex)-induced osteoporosis model.
Methods
C57BL/6J mice were intraperitoneally injected with Dex to establish an osteoporosis model. Mouse femur bone injury and bone formation were detected using hematoxylin-eosin or Masson staining. Apoptosis and cell cycle distribution were determined by flow cytometry. Alkaline phosphatase (ALP) activity and calcified nodules were monitored using ALP and Alizarin Red S staining. The molecular mechanism was validated by co-immunoprecipitation (Co-IP) and ubiquitination assays.
Results
CUL1 expression was enhanced in the Dex-induced osteoporosis mouse model. CUL1 silencing moderated the Dex-induced cell proliferation and osteogenesis inhibition. Moreover, CUL1 promoted the ubiquitination and degradation of ASAP1 via the SKP1-CUL1-F-box (SCF)-FBXW7 complex. CUL1 induced apoptosis and repressed osteogenesis by ASAP1. CUL1 silencing alleviated the Dex-induced osteoporosis in mice.
Conclusion
CUL1 suppressed osteoblast proliferation and osteogenesis by promoting ASAP1 ubiquitination via the SCF-FBXW7 complex in glucocorticoid-induced osteoporosis.