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Avin KG, Vallejo JA, Chen NX, Wang K, Touchberry CD, Brotto M, Dallas SL, Moe SM, Wacker MJ. Fibroblast growth factor 23 does not directly influence skeletal muscle cell proliferation and differentiation or ex vivo muscle contractility. Am J Physiol Endocrinol Metab 2018; 315:E594-E604. [PMID: 29558205 PMCID: PMC6230710 DOI: 10.1152/ajpendo.00343.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 01/29/2018] [Accepted: 02/15/2018] [Indexed: 02/06/2023]
Abstract
Skeletal muscle dysfunction accompanies the clinical disorders of chronic kidney disease (CKD) and hereditary hypophosphatemic rickets. In both disorders, fibroblast growth factor 23 (FGF23), a bone-derived hormone regulating phosphate and vitamin D metabolism, becomes chronically elevated. FGF23 has been shown to play a direct role in cardiac muscle dysfunction; however, it is unknown whether FGF23 signaling can also directly induce skeletal muscle dysfunction. We found expression of potential FGF23 receptors ( Fgfr1-4) and α-Klotho in muscles of two animal models (CD-1 and Cy/+ rat, a naturally occurring rat model of chronic kidney disease-mineral bone disorder) as well as C2C12 myoblasts and myotubes. C2C12 proliferation, myogenic gene expression, oxidative stress marker 8-OHdG, intracellular Ca2+ ([Ca2+]i), and ex vivo contractility of extensor digitorum longus (EDL) or soleus muscles were assessed after treatment with various amounts of FGF23. FGF23 (2-100 ng/ml) did not alter C2C12 proliferation, expression of myogenic genes, or oxidative stress after 24- to 72-h treatment. Acute or prolonged FGF23 treatment up to 6 days did not alter C2C12 [Ca2+]i handling, nor did acute treatment with FGF23 (9-100 ng/ml) affect EDL and soleus muscle contractility. In conclusion, although skeletal muscles express the receptors involved in FGF23-mediated signaling, in vitro FGF23 treatments failed to directly alter skeletal muscle development or function under the conditions tested. We hypothesize that other endogenous substances may be required to act in concert with FGF23 or apart from FGF23 to promote muscle dysfunction in hereditary hypophosphatemic rickets and CKD.
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Affiliation(s)
- Keith G Avin
- Department of Physical Therapy, School of Health and Rehabilitation Sciences, Indiana University , Indianapolis, Indiana
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Julian A Vallejo
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City , Kansas City, Missouri
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City , Kansas City, Missouri
| | - Neal X Chen
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Kun Wang
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City , Kansas City, Missouri
| | - Chad D Touchberry
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City , Kansas City, Missouri
| | - Marco Brotto
- College of Nursing and Health Innovation, Bone-Muscle Collaborative Sciences, University of Texas-Arlington , Arlington, Texas
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City , Kansas City, Missouri
| | - Sharon M Moe
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
- Roudebush Veterans Administration Medical Center , Indianapolis, Indiana
| | - Michael J Wacker
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City , Kansas City, Missouri
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