Cited by 64Exercise and Physiological ResponsesAdipokines, Inflammation, and Metabolic DiseasesMuscle Physiology and Disorders

Effect of obesity and exercise on the expression of the novel myokines, Myonectin and Fibronectin type III domain containing 5

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Peterson, Jonathan M., Mart, Ryan, Bond, Cherie E.·2014·PeerJ

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Abstract

Metabolic dysfunction in skeletal muscle is a major contributor to the development of type 2 diabetes. Endurance exercise training has long been established as an effective means to directly restore skeletal muscle glucose and lipid uptake and metabolism. However, in addition to the direct effects of skeletal muscle on glucose and lipids, there is renewed interest in the ability of skeletal muscle to coordinate metabolic activity of other tissues, such as adipose tissue and liver. The purpose of this study was to examine the effects of endurance exercise on the expression level of two novel muscle-derived secreted factors, or myokines, Myonectin and Fibronectin type III domain containing 5 (FNDC5), the precursor for Irisin. Methods. We performed immunoblot analysis and quantitative real-time PCR analysis of Myonectin and FNDC5 in the diaphragm muscles of obese Zucker rat (OZR) and lean Zucker rat (LZR) with 9 weeks of aerobic training on a motorized treadmill. Results. We show that myonectin gene expression is increased in the OZR model of obesity and decreases with exercise in both lean and obese Zucker rats. Conversely, myonectin protein concentration was elevated with exercise. Similarly, FNDC5 mRNA levels are significantly higher in the OZR, however exercise training had no effect on the expression level of FNDC5 in either the LZR or OZR. We did not observe any difference in muscle protein content of Irisin with obesity or exercise. Conclusion. Our data shows that exercise training does not increase either FNDC5 or myonectin gene expression, indicating that increased transcriptional regulation of these myokines is not induced by exercise. However, our data also indicates a yet to be explored disconnect between myonectin gene expression and protein content. Further, this report highlights the importance of verifying reference genes when completing gene expression analysis. We found that many commonly used reference genes varied significantly by obesity and/or exercise and would have skewed the results of this study if used to normalize gene expression data. The unstable reference genes include: beta-Actin, beta-2-microglobulin, Non-POU domain containing, octamer-binding, Peptidylprolyl isomerase H, 18S ribosomal RNA, TATA box binding protein and Transferrin receptor.

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Authors
Peterson, J. M., Mart, R., & Bond, C. E.
Affiliations
East Tennessee State University (US)
Venue
PeerJ
Publisher
PeerJ
Published
2014-09-30
Volume
2
Pages
e605
ISSN
2167-8359 (ISSN-L)
OpenAlex
W2162744978
Cited by
64
References
36
Citations by year
2026: 2 · 2025: 3 · 2024: 6 · 2023: 7 · 2022: 5 · 2021: 7 · 2020: 14 · 2019: 3 · 2018: 8 · 2017: 5 · 2015: 4
FWCI
2.91
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • PeerJ (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Digital Commons - East Tennessee State University (East Tennessee State University) (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Health Sciences › Medicine › Rehabilitation › Exercise and Physiological Responses
  • Health Sciences › Medicine › Epidemiology › Adipokines, Inflammation, and Metabolic Diseases
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Muscle Physiology and Disorders
Keywords
myokines, myonectin, FNDC5, irisin, obesity, endurance training, skeletal muscle, diaphragm, gene expression, reference genes, gene normalization, type 2 diabetes, metabolic dysfunction, Zucker rats

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