Hypergravity induces changes in physiology, gene expression and epigenetics in zebrafish

All living organisms that inhabit Earth have evolved under a common value of gravity, which amounts to an acceleration of 9.81 m/s2 at mean sea level. Changes on it could cause important alterations that affect vital biological functions. The crescent interest in spatial exploration has opened the question of how exactly these changes in gravity would affect Earth life forms on space environments. This work is the result of a collaborative co-supervision of a master thesis between experts in the area of space sciences and biology, and it can serve as a case study for training experts in such interdisciplinary environments. In particular, we focus on the effect of gravity as a pressure factor in the development of zebrafish (Danio rerio) in the larval stage as a model organism using up-to-date (genomic and epigenetic) techniques. Given the high cost of any experiment in true low gravity (which would require a space launch), we performed an initial experiment in hypergravity to develop the methodologies and identify good (epi)genetic markers of the effect of gravity in our model organism. Previous studies in zebrafish have shown how alteration in gravity effects the development and the gene expression of important regulatory genes. For this study, we firstly customized a small laboratory scale centrifuge to study changes in fish physiology together with changes at molecular levels. We exposed zebrafish larvae from 0 to 6 days post fertilization to the simulated hypergravity (SHG) (100 rpm  3g). After 6 days of hypergravity exposition the larvae showed changes in their swimming and flotation patterns, and presented corporal alterations. Then, we assessed gene expression of genes implicated in important biological processes, (e.g., epigenetics), and an upregulation were observed when compared to the control. Taken together, these preliminary findings show how gravity alterations could affect some basic biological responses, and illustrate the potential of developing new science cases to be developed by students at postgraduate level (MSc and beyond) in a multidisciplinary environment