A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development

Abstract Bone remodeling is tightly regulated by the RANK-RANKL-OPG axis to maintain skeletal integrity. We previously identified a RANK splicing variant, vRANK, which encodes a truncated protein that inhibits osteoclastogenesis and promotes apoptosis. This study examined the regulatory mechanisms o...

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Main Authors: Riko Kitazawa, Ryuma Haraguchi, Sohei Kitazawa
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-13314-7
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author Riko Kitazawa
Ryuma Haraguchi
Sohei Kitazawa
author_facet Riko Kitazawa
Ryuma Haraguchi
Sohei Kitazawa
author_sort Riko Kitazawa
collection DOAJ
description Abstract Bone remodeling is tightly regulated by the RANK-RANKL-OPG axis to maintain skeletal integrity. We previously identified a RANK splicing variant, vRANK, which encodes a truncated protein that inhibits osteoclastogenesis and promotes apoptosis. This study examined the regulatory mechanisms of vRANK expression in vitro and its physiological role in vivo using transgenic mice with forced vRANK expression in the monocyte-macrophage lineage and in a systemic manner. In vitro, PMA and TGF-β1 specifically induced vRANK expression, which was completely suppressed by U0126, a MEK1/2 inhibitor, and significantly reduced by Sam68 knockdown, indicating its involvement in RNA splicing regulation. In vivo, RANK-Cre-driven vRANK expression had no skeletal impact, whereas LysM-Cre-driven expression resulted in increased bone mass and suppressed osteoclastogenesis. However, systemic overexpression of vRANK (CAG-CreER) caused perinatal lethality, severe cardiac fibrosis, and immune dysfunction. Notably, myocardial fibrosis in vRANK-overexpressing mice correlated with TGF-β1 upregulation in fibrotic foci, suggesting a pathological feedback loop exacerbating fibrosis. These findings suggest that vRANK functions similarly to OPG in inhibiting osteoclastogenesis while also potentially playing a role in cardiac remodeling and immune regulation.
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spelling doaj-art-94e941b127a848cba2c59bfdc3f1b9c62025-08-20T04:01:51ZengNature PortfolioScientific Reports2045-23222025-07-0115111610.1038/s41598-025-13314-7A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac developmentRiko Kitazawa0Ryuma Haraguchi1Sohei Kitazawa2Department of Molecular Pathology, Ehime University Graduate School of MedicineDepartment of Molecular Pathology, Ehime University Graduate School of MedicineDepartment of Molecular Pathology, Ehime University Graduate School of MedicineAbstract Bone remodeling is tightly regulated by the RANK-RANKL-OPG axis to maintain skeletal integrity. We previously identified a RANK splicing variant, vRANK, which encodes a truncated protein that inhibits osteoclastogenesis and promotes apoptosis. This study examined the regulatory mechanisms of vRANK expression in vitro and its physiological role in vivo using transgenic mice with forced vRANK expression in the monocyte-macrophage lineage and in a systemic manner. In vitro, PMA and TGF-β1 specifically induced vRANK expression, which was completely suppressed by U0126, a MEK1/2 inhibitor, and significantly reduced by Sam68 knockdown, indicating its involvement in RNA splicing regulation. In vivo, RANK-Cre-driven vRANK expression had no skeletal impact, whereas LysM-Cre-driven expression resulted in increased bone mass and suppressed osteoclastogenesis. However, systemic overexpression of vRANK (CAG-CreER) caused perinatal lethality, severe cardiac fibrosis, and immune dysfunction. Notably, myocardial fibrosis in vRANK-overexpressing mice correlated with TGF-β1 upregulation in fibrotic foci, suggesting a pathological feedback loop exacerbating fibrosis. These findings suggest that vRANK functions similarly to OPG in inhibiting osteoclastogenesis while also potentially playing a role in cardiac remodeling and immune regulation.https://doi.org/10.1038/s41598-025-13314-7RANKOsteoclastsBoneHeartSam68
spellingShingle Riko Kitazawa
Ryuma Haraguchi
Sohei Kitazawa
A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development
Scientific Reports
RANK
Osteoclasts
Bone
Heart
Sam68
title A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development
title_full A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development
title_fullStr A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development
title_full_unstemmed A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development
title_short A variant form of receptor activator of nuclear factor-κB functions as an osteoprotegerin mimic in bone and cardiac development
title_sort variant form of receptor activator of nuclear factor κb functions as an osteoprotegerin mimic in bone and cardiac development
topic RANK
Osteoclasts
Bone
Heart
Sam68
url https://doi.org/10.1038/s41598-025-13314-7
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