Differential but complementary roles of HIF-1α and HIF-2α in the regulation of bone homeostasis.
Commun Biol
; 7(1): 892, 2024 Jul 23.
Article
em En
| MEDLINE
| ID: mdl-39039245
ABSTRACT
Bone is a highly dynamic tissue undergoing continuous formation and resorption. Here, we investigated differential but complementary roles of hypoxia-inducible factor (HIF)-1α and HIF-2α in regulating bone remodeling. Using RNA-seq analysis, we identified that specific genes involved in regulating osteoblast differentiation were similarly but slightly differently governed by HIF-1α and HIF-2α. We found that increased HIF-1α expression inhibited osteoblast differentiation via inhibiting RUNX2 function by upregulation of Twist2, confirmed using Hif1a conditional knockout (KO) mouse. Ectopic expression of HIF-1α via adenovirus transduction resulted in the increased expression and activity of RANKL, while knockdown of Hif1a expression via siRNA or osteoblast-specific depletion of Hif1a in conditional KO mice had no discernible effect on osteoblast-mediated osteoclast activation. The unexpected outcome was elucidated by the upregulation of HIF-2α upon Hif1a overexpression, providing evidence that Hif2a is a transcriptional target of HIF-1α in regulating RANKL expression, verified through an experiment of HIF-2α knockdown after HIF-1α overexpression. The above results were validated in an ovariectomized- and aging-induced osteoporosis model using Hif1a conditional KO mice. Our findings conclude that HIF-1α plays an important role in regulating bone homeostasis by controlling osteoblast differentiation, and in influencing osteoclast formation through the regulation of RANKL secretion via HIF-2α modulation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Osteoblastos
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Camundongos Knockout
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Fatores de Transcrição Hélice-Alça-Hélice Básicos
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Subunidade alfa do Fator 1 Induzível por Hipóxia
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Homeostase
Limite:
Animals
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article