Circulating MiR-21 expression is upregulated after 30 days of head-down tilt bed rest

Authors

Debra A. Bemben, University of Oklahoma
B. S. Baker
Samuel R. Buchanan, The University of Texas Rio Grande ValleyFollow
C. J. Ade

Document Type

Article

Publication Date

1-11-2021

Abstract

Summary

Relative expression of miR-21-5p in serum was upregulated in response to 30 days of bed rest, and miRNA fold changes were positively associated with serum calcium changes.

Introduction

Circulating miRNAs (c-miRNAs) have potential as biomarkers of cellular activity, and they may play a role in cell-to-cell communication. The purpose of this study was to examine c-miRNA and bone marker responses to a 30-day six-degree head-down bed rest protocol at an ambient 0.5% CO2.

Methods

Eleven participants (6 males/5 females, 25–50 years) had fasting blood draws taken 3 days before and immediately after completing the 30-day bed rest protocol at the Institute for Aerospace Medicine in Germany. Serum relative expression of miRNAs associated with bone function (miR-21-5p, -100-5p, -125b-5p, -126-3p) were analyzed using qPCR, and serum bone markers were quantitated using ELISA.

Results

Serum bone markers, sclerostin, and calcium significantly increased (p ≤ 0.036), and total hip aBMD significantly decreased (p = 0.003) post bed rest. Serum miR-21-5p relative expression was significantly upregulated (p = 0.018) post bed rest. Fold changes in miR-126-3p (r = 0.82, p = 0.002) and miR-21-5p (r = 0.62, p = 0.042) were positively correlated with absolute change in serum calcium. There were no sex differences in miRNA responses; women had greater percent increases in TRAP5b (37.3% vs. 16.9% p = 0.021) and greater percent decreases in total hip aBMD (− 2.15% vs. − 0.69%, p = 0.034) than men.

Conclusion

c-miR-21-5p has potential as a biomarker of bone resorption and bone loss in an unloading condition. The upregulation of miR-21-5p may reflect an increase in osteoclast activity after bed rest, which is corroborated by the increase in TRAP5b.

Comments

Copyright © 2021, International Osteoporosis Foundation and National Osteoporosis Foundation

https://rdcu.be/c39hr

Recommended Citation

Bemben, D., Baker, B., Buchanan, S. et al. Circulating MiR-21 expression is upregulated after 30 days of head-down tilt bed rest. Osteoporos Int 32, 1369–1378 (2021). https://doi.org/10.1007/s00198-020-05805-2

DOI

10.1007/s00198-020-05805-2