Mesenchymal stem cells are undifferentiated cells able to acquire different phenotypes under specific stimuli. Wharton’s jelly is a tissue in the umbilical cord that contains mesenchymal stromal cells (MSCs) with a high plasticity and differentiation potential. Their regeneration capability is compromised by cell damage and aging. The main cause of cell damage is oxidative stress coming from an imbalance between oxidant and antioxidant species. Microgravity represents a stressing condition able to induce ROS production, ultimately leading to different subcellular compartment damages. Here, we analyzed molecular programs of stemness (Oct-4; SOX2; Nanog), cell senescence, p19, p21 (WAF1/CIP1), p53, and stress response in WJ-MSCs exposed to microgravity. From our results, we can infer that a simulated microgravity environment is able to influence WJ-MSC behavior by modulating the expression of stress and stemness-related genes, cell proliferation regulators, and both proapoptotic and antiapoptotic genes. Our results suggest a cellular adaptation addressed to survival occurring during the first hours of simulated microgravity, followed by a loss of stemness and proliferation capability, probably related to the appearance of a molecular program of senescence.

Microgravity may profoundly impact the cardiovascular system, skeletal muscle system, and immune system of astronauts. At the cellular level, microgravity may also affect cell proliferation, differentiation, and growth, as well as lipid metabolism. In this work, we investigated lipid changes in Caco-2 cells cultured in a clinostat for 24 h under simulated microgravity conditions (SMC). Complex lipids were measured using a UHPLC-QTOF/MS platform, and the data were subjected to multivariate analysis. Under SMC, levels of ceramides Cer 18:0;O2/16:0, Cer 18:1;O2/16:0, Cer 18:1; O2/22:0, Cer 18:1;O2/24:0, and Cer 18:2;O2/24:0 were found to be upregulated, while sphingomyelins SM 16:1;O2/16:0, SM 16:1;O2/18:1, SM 18:1;O2/24:0, and SM 18:2;O2/24:0 were found to be downregulated. On the other hand, considering that sphingolipids are involved in the process of inflammation, we also treated Caco-2 cells with dextran sodium sulfate (DSS) to induce cell inflammation and lipopolysaccharide (LPS) to induce cell immune responses. As a result, we observed similar lipid dysregulation, indicating that SMC may exert a condition similar to inflammation. Our lipidomics strategy provides new insights into the altered metabolic pathway of ceramides and sphingomyelins of Caco-2 cells under SMC.

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the accumulation of alpha-synuclein aggregates and progressive neuronal loss in the substantia nigra, with aging being its primary risk factor. The current available models to study PD mechanisms are largely relying on genetic mutations to recapitulate PD typical hallmarks, such as increased alpha-synuclein aggregation. However, they do not model the aging features associated with the disease. Microgravity, a condition experience by astronauts during space missions, is known to induce ageing-like modifications on both systemic and cellular physiology. To replicate the aging-related stress observed in PD patients, we exposed SH-SY5Y and 3K-SNCA mutant cell lines to simulated microgravity. Our findings revealed that simulated microgravity enhanced PD alterations, with a significant increase in misfolded and phosphorylated a-syn. This was accompanied by heightened oxidative stress, as evidenced by increased levels of reactive oxygen species, without a sufficient antioxidant response. These results suggest that simulated microgravity effectively mimics and accelerate the stress associated with aging in PD cell models, regardless of the presence of PD mutation. This study highlights the potential of simulated microgravity as a tool for investigating aging processes in neurodegenerative diseases.