Table 5.
Literature overview of the effects of microgravity on cell organelles, structures and morphology observed in mammalian cells or molecules exposed to real microgravity on different platforms (PF: Parabolic flight, SR: Suborbital rocket, SF: Space flight).
| Effects on Cells, Cell-Organelles, and Cell-Structures | Cell Type | References | Microgravity Platform | Microgravity Exposure Time |
|---|---|---|---|---|
| Cell morphology | ||||
| Cytoplasmic retraction and membrane ruffling, decreased cell area | Osteosarcoma cells (ROS 17/2.8) | [48] | PF | 15 parabolas, 30 parabolas |
| Decreased cell area | Osteosarcoma cells (ROS 17/2.8) | [49] | PF | 15 parabolas, 30 parabolas |
| No shape change at two days microgravity | Osteosarcoma cells (ROS 17/2.8) | [66] | SF | two days |
| Shape change at 4 and 6 days microgravity: Round, increase in microvilli, three sub-groups of morphology (1) long cytoplasmic extensions; (2) round piling cells, unable to flatten; (3) normal spread out cells, resembling the ground controls | Osteosarcoma cells (ROS 17/2.8) | [66] | SF | four days, six days |
| Decrease of cell area, number of vinculin spots and mean vinculin spot area | Osteosarcoma cells (ROS 17/2.8) | [57] | SF | 12 h, 24 h |
| Decreased cell area, decreased number of vinculin spots per cell, decreased mean vinculin spot area, actin and focal adhesion decreased, fewer stress fibers, vimentin and microtubule network no major differences (12 h and 24 h) | Osteosarcoma cells (ROS 17/2.8) | [50] | SF | 12 h, 24 h |
| Contracted, roundish cell shape with short protrusions | J-111 cell line | [52] | SF | one day |
| Nuclear shape | ||||
| Reduced nuclei size by 30%, oblong shape, less punctate areas, actin cytoskeleton with a reduced number of stress fibers | MC3T3-E1 osteoblasts | [51] | SF | four days |
| High variability, many smaller and condensed and some fragmented nuclei, larger intact nuclei with larger diameter | Primary mouse osteoblasts, RAW 264.7 murine macrophage cell line | [58] | SF | five days |
| Other cellular organelles | ||||
| Increased cellular organelle volume of lysosome-like bodies, autophagosomes, Golgi complex, vacuoles and vesicles | Osteocytes, ileac crest of monkeys | [47] | SF | 14 days |
| Cytoskeleton | ||||
| Actin cytoskeleton with a reduced number of stress fibers perinuclear actin localization, lamellipodia | MC3T3-E1 osteoblasts | [51] | SF | four days |
| No changes in actin structure | Human Jurkat T cells | [10] | SR | 12 min |
| Localization of actin at cell border, contracted cell shape, changed the distribution of F-actin and tubulin filaments, no strong bundles, fewer lamellipodia | J-111 cell line | [52] | SF | one day |
| Accumulation of F-actin at the cell membrane, increase in F-actin around nucleus | Human endothelial cells | [53] | PF | one parabola |
| Rearrangement of the actin network, perinuclear clustering | ML-1 follicular thyroid cancer cells | [54] | PF | one parabola |
| Disturbance of actin bundles and cytoplasm discontinuity, disappearance of the microvilli or filopodia- and lamellipodia-like structures | follicular thyroid cancer cells FTC-133 | [11] | PF | 1–2 parabolas |
| Disturbance of actin bundles, formation of filopodia- and lamellipodia like structures, cellular detachment | follicular thyroid cancer cells FTC-133 | [11] | SR | six min |
| No changes of the actin and vimentin cytoskeleton structure | Primary human macrophages | [23] | SF | 11 days |
| Formation of thick vimentin and tubulin bundles, formation of aggregates of proteins, due to de-polymerization and discontinuities of the filamentous network | Human T lymphocytes from blood donations | [67] | SR | 30 s |
| Disorganization of microtubules | Human Jurkat T cells | [12] | SF | four h |
| Vimentin structural changes, increased appearance of large bundles | Human Jurkat T cells | [10] | SR | 12 min |
| No microtubule self-organization and local disorder | Purified tubulin from cow brains | [61] | SR | 13 min |
| Altered microtubule cytoskeleton after 4 h and partial re-organization after 48 h | Human Jurkat T cells | [55] | SF | four h, 48 h |
| Disoriented microtubule | Breast cancer MCF-7 | [56] | SF | 1.5 h |
| Presence of thicker, bundled microtubule, smaller focal adhesion size, reduced cortical actin, fewer actin stress fibers with reduced fiber thickness, a significant increase in cell area measured with phalloidin | Primary mouse osteoblasts, RAW 264.7 murine macrophage cell line | [58] | SF | five days |
| Disorganized sarcomeric structure with interfilament holes | C57BL/6N mice Cardiac muscle | [60] | SF | 30 days |
| Cell cytoplasm discontinuity, holes in the microtubule network, absence of stress fibers, actin network rearrangement and ring formation around the cell membrane | Human chondrocytes | [59] | PF | one parabola, 31 parabolas |
| No changes of the actin cytoskeleton structure | Primary humane fibroblasts | [68] | SF | three days, 14 days |