Engineering radioprotective human cells using the tardigrade Damage Suppressor Protein, DSUP

Spaceflight has been documented to produce a number of detrimental effects to physiology and genomic stability, partly a result of Galactic Cosmic Radiation (GCR). In recent years, extensive research into extremotolerant organisms has begun to reveal how they survive harsh conditions, such as ionizing radiation.

One such organism is the tardigrade (Ramazzottius varieornatus) which can survive up to 5kGy of ionizing radiation and also survive the vacuum of space. In addition to their extensive network of DNA damage and response mechanisms, the tardigrade also possesses a unique damage suppressor protein (Dsup) that co-localizes with chromatin in both tardigrade and transduced human cells and protects against damage from reactive oxygen species via ionizing radiation.

While Dsup has been shown to confer human cells with radioresistance; much of the mechanism of how it does this in the context of human cells remains to be elucidated. In addition, there is no knowledge yet of how introduction of Dsup into human cells can perturb cellular networks and if there are any systemic risks associated.

Here, we created a stable HEK293 cell line expressing Dsup via lentiviral transduction and confirmed its presence and its integration site. We show that Dsup confers human cells with a reduction of apoptotic signals. Through measuring these biomarkers of DNA damage in response to irradiation longitudinally along with gene expression analysis, we were able to demonstrate a potential role for Dsup as DNA damage response and repair enhancer much in the same way its human homologous counterpart HMGN1 functions.

Our methods and tools provide evidence that the effects of the Dsup protein can be potentially utilized to mitigate such damage during spaceflight.