How Microgravity Changes Galectin-3 in Thyroid Follicles

Abstract

After long-term exposure to real microgravity thyroid gland in vivo undergoes specific changes, follicles are made up of larger thyrocytes that produce more cAMP and express more thyrotropin-receptor, caveolin-1, and sphingomyelinase and sphingomyelin-synthase; parafollicular spaces lose C cells with consequent reduction of calcitonin production. Here we studied four immunohistochemical tumor markers (HBME-1, MIB-1, CK19, and Galectin-3) in thyroid of mice housed in the Mouse Drawer System and maintained for 90 days in the International Space Station. Results showed that MIB-1 proliferative index and CK19 are negative whereas HBME-1 and Galectin-3 are overexpressed. The positivity of Galectin-3 deserves attention not only for its expression but also and especially for its localization. Our results highlighted that, in microgravity conditions, Galectin-3 leaves thyrocytes and diffuses in colloid. It is possible that the gravity force contributes to the maintenance of the distribution of the molecules in both basal membrane side and apical membrane side and that the microgravity facilitates slippage of Galectin-3 in colloid probably due to membrane remodelling-microgravity induced.

Pathways Regulating Spheroid Formation of Human Follicular Thyroid Cancer Cells under Simulated Microgravity Conditions: A Genetic Approach

“…This is the first study, using pathway analyses programs to investigate the molecular mechanisms responsible for 3D growth of follicular thyroid cancer cells grown under conditions of simulated microgravity for 24 h on the RPM. Earlier studies have shown, that human and rat benign thyroid cells as well as cancer cells in vitro and in vivo respond to microgravity conditions and induce a variety of changes in these cells [ 3 , 8 , 17 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 ]. This response might give important hints for cancer research on Earth [ 87 ].…”

Cytokine Release and Focal Adhesion Proteins in Normal Thyroid Cells Cultured on the Random Positioning Machine

“…The objective of this project was to monitor changes occurring during short-term RPM-exposure in normal human thyrocytes with respect to the influence of soluble factors on proteins involved in focal adhesion. These findings might help to further understand the observed impact of microgravity on the formation of 3D aggregates of normal human thyrocytes and other cells [4, 5]. …”

“…There are reports about various health concerns such as dysfunctions of the musculoskeletal and cardiovascular system, a down-regulation of the immune system, and visual problems [1-3]. In space, the thyroid gland in vivo revealed a variety of changes such as follicles with larger thyrocytes and increases in cAMP, thyrotropin-receptors (TSHR), and caveolin-1 [4, 5]. On the cellular level, it is known that both real (r-µ g ) and simulated microgravity (s-µ g ) influence growth behaviour, gene expression pattern, protein synthesis and secretion in thyroid cancer cells [6-11].…”

Fighting Thyroid Cancer with Microgravity Research

“…In cross sections, the follicles of the healthy thyroid gland are round or oval. Microgravity changes the thyroid follicles [20]. The follicles reveal larger thyrocytes and show an elevation of cyclic adenosine monophosphate (cAMP), thyrotropin-receptors and caveolin-1 [20,21].…”

“…Microgravity changes the thyroid follicles [20]. The follicles reveal larger thyrocytes and show an elevation of cyclic adenosine monophosphate (cAMP), thyrotropin-receptors and caveolin-1 [20,21]. Earlier in vitro and in vivo experiments demonstrated that thyrocytes respond to µ g and hypergravity conditions [22,23,24,25,26].…”