A firmer understanding of the effect of hypergravity on thyroid tissue: cholesterol and thyrotropin receptor

PLoS One. 2014 May 27;9(5):e98250. doi: 10.1371/journal.pone.0098250. eCollection 2014.

Abstract

Maintaining a good health requires the maintenance of a body homeostasis which largely depends on correct functioning of thyroid gland. The cells of the thyroid tissue are strongly sensitive to hypogravity, as already proven in mice after returning to the earth from long-term space missions. Here we studied whether hypergravity may be used to counteract the physiological deconditioning of long-duration spaceflight. We investigated the influence of hypergravity on key lipids and proteins involved in thyroid tissue function. We quantified cholesterol (CHO) and different species of sphingomyelin (SM) and ceramide, analysed thyrotropin (TSH) related molecules such as thyrotropin-receptor (TSHR), cAMP, Caveolin-1 and molecule signalling such as Signal transducer and activator of transcription-3 (STAT3). The hypergravity treatment resulted in the upregulation of the TSHR and Caveolin-1 and downregulation of STAT3 without changes of cAMP. TSHR lost its specific localization and spread throughout the cell membrane; TSH treatment facilitated the shedding of α subunit of TSHR and its releasing into the extracellular space. No specific variations were observed for each species of SM and ceramide. Importantly, the level of CHO was strongly reduced. In conclusion, hypergravity conditions induce change in CHO and TSHR of thyroid gland. The possibility that lipid rafts are strongly perturbed by hypergravity-induced CHO depletion by influencing TSH-TSHR interaction was discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Caveolin 1 / metabolism
  • Cholesterol / metabolism*
  • Chromatography, Liquid
  • Cyclic AMP / metabolism
  • Fluorescent Antibody Technique
  • Hypergravity*
  • Mice
  • Mice, Inbred C57BL
  • Receptors, Thyrotropin / metabolism*
  • Signal Transduction
  • Tandem Mass Spectrometry
  • Thyroid Gland / cytology
  • Thyroid Gland / physiology*
  • Thyrotropin / metabolism

Substances

  • Caveolin 1
  • Receptors, Thyrotropin
  • Thyrotropin
  • Cholesterol
  • Cyclic AMP

Grants and funding

This work has been supported by Agenzia Spaziale Italiana (ASI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.