Computational Analysis of the Effect of Inhibitor Proteins P21/p27 on Cell Cycle Under Microgravity Conditions

The cell cycle progression is fundamental for the life of all living organisms and its alteration from physiological conditions may interfere with its primary function, thus driving potentially harmful consequences. More specifically, during space missions, astronauts are continuously exposed to non-physiological conditions due to microgravity and suffer from a series of health issues once come back to earth; exposure to real or simulated microgravity conditions can disrupt normal cell cycle regulation. For this reason, the possibility to predict any change in cell division time could represent a valuable tool for understanding the pathologies and health issues experienced by astronauts during their time in orbit. In this study, we employed a previously developed mathematical model to simulate the impact of the inhibitor proteins p21 and p27 on cell cycle progression. These proteins are known to be overexpressed under microgravity conditions, potentially leading to altered or even arrested cell division, depending on the extent of the overexpression. In particular, the aim of this work is the analysis of p21/p27 over expression induced by microgravity, with particular attention to its effect on cell duplication time and quality. Indeed, depending on the extent of such an over expression, not only duplication time varies but also cellular abnormalities such as biperiodic duplication, endoreplication or tetraploidy, as well as cessation of cell replication may take place.