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Pellegrini GG, Cregor M, McAndrews K, Morales CC, McCabe LD, McCabe GP, Peacock M, Burr D, Weaver C, Bellido T. Nrf2 regulates mass accrual and the antioxidant endogenous response in bone differently depending on the sex and age. PLoS One 2017; 12:e0171161. [PMID: 28152064 PMCID: PMC5289572 DOI: 10.1371/journal.pone.0171161] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/17/2017] [Indexed: 01/28/2023] Open
Abstract
Accumulation of reactive oxygen species (ROS) is an important pathogenic mechanism underling the loss of bone mass and strength with aging and other conditions leading to osteoporosis. The transcription factor erythroid 2-related factor2 (Nrf2) plays a central role in activating the cellular response to ROS. Here, we examined the endogenous response of bone regulated by Nrf2, and its relationship with bone mass and architecture in the male and female murine skeleton. Young (3 month-old) and old (15 month-old) Nrf2 knockout (KO) mice of either sex exhibited the expected reduction in Nrf2 mRNA expression compared to wild type (WT) littermates. Nrf2 deletion did not lead to compensatory increase in Nrf1 or Nrf3, other members of this transcription factor family; and instead, Nrf1 expression was lower in KO mice. Compared to the respective WT littermate controls, female KO mice, young and old, exhibited lower expression of both detoxifying and antioxidant enzymes; young male KO mice, displayed lower expression of detoxifying enzymes but not antioxidant enzymes; and old male KO mice showed no differences in either detoxifying or antioxidant enzymes. Moreover, old male WT mice exhibited lower Nrf2 levels, and consequently lower expression of both detoxifying and antioxidant enzymes, compared to old female WT mice. These endogenous antioxidant responses lead to delayed rate of bone acquisition in female KO mice and higher bone acquisition in male KO mice as quantified by DXA and μCT, demonstrating that Nrf2 is required for full bone accrual in the female skeleton but unnecessary and even detrimental in the male skeleton. Therefore, Nrf2 regulates the antioxidant endogenous response and bone accrual differently depending on sex and age. These findings suggest that therapeutic interventions that target Nrf2 could be developed to enhance the endogenous antioxidant response in a sex- and age-selective manner.
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Affiliation(s)
- Gretel Gisela Pellegrini
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Meloney Cregor
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Kevin McAndrews
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Cynthya Carolina Morales
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Linda Doyle McCabe
- Department of Statistics, Purdue University, West Lafayette, Indiana, United States of America
| | - George P. McCabe
- Department of Statistics, Purdue University, West Lafayette, Indiana, United States of America
| | - Munro Peacock
- Department of Medicine, Division of Endocrinology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - David Burr
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Connie Weaver
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Teresita Bellido
- Department of Anatomy and Cell Biology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
- Department of Medicine, Division of Endocrinology, School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, Indiana, United States of America
- Roudebush Veterans Administration Medical Center, Indianapolis, Indiana, United States of America
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