B4GALNT3 regulates glycosylation of sclerostin and bone massResearch in context

Autor: Sofia Movérare-Skrtic, Jakob Voelkl, Karin H. Nilsson, Maria Nethander, Trang Thi Doan Luong, Ioana Alesutan, Lei Li, Jianyao Wu, Karin Horkeby, Marie K. Lagerquist, Antti Koskela, Juha Tuukkanen, Jon H. Tobias, Ulf H. Lerner, Petra Henning, Claes Ohlsson
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: EBioMedicine, Vol 91, Iss , Pp 104546- (2023)
Druh dokumentu: article
ISSN: 2352-3964
DOI: 10.1016/j.ebiom.2023.104546
Popis: Summary: Background: Global sclerostin inhibition reduces fracture risk efficiently but has been associated with cardiovascular side effects. The strongest genetic signal for circulating sclerostin is in the B4GALNT3 gene region, but the causal gene is unknown. B4GALNT3 expresses the enzyme beta-1,4-N-acetylgalactosaminyltransferase 3 that transfers N-acetylgalactosamine onto N-acetylglucosaminebeta-benzyl on protein epitopes (LDN-glycosylation). Methods: To determine if B4GALNT3 is the causal gene, B4galnt3−/− mice were developed and serum levels of total sclerostin and LDN-glycosylated sclerostin were analysed and mechanistic studies were performed in osteoblast-like cells. Mendelian randomization was used to determine causal associations. Findings: B4galnt3−/− mice had higher circulating sclerostin levels, establishing B4GALNT3 as a causal gene for circulating sclerostin levels, and lower bone mass. However, serum levels of LDN-glycosylated sclerostin were lower in B4galnt3−/− mice. B4galnt3 and Sost were co-expressed in osteoblast-lineage cells. Overexpression of B4GALNT3 increased while silencing of B4GALNT3 decreased the levels of LDN-glycosylated sclerostin in osteoblast-like cells. Mendelian randomization demonstrated that higher circulating sclerostin levels, genetically predicted by variants in the B4GALNT3 gene, were causally associated with lower BMD and higher risk of fractures but not with higher risk of myocardial infarction or stroke. Glucocorticoid treatment reduced B4galnt3 expression in bone and increased circulating sclerostin levels and this may contribute to the observed glucocorticoid-induced bone loss. Interpretation: B4GALNT3 is a key factor for bone physiology via regulation of LDN-glycosylation of sclerostin. We propose that B4GALNT3-mediated LDN-glycosylation of sclerostin may be a bone-specific osteoporosis target, separating the anti-fracture effect of global sclerostin inhibition, from indicated cardiovascular side effects. Funding: Found in acknowledgements.
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