The fate of the TARDIS offspring: no intergenerational effects of space exposure

DSUP modified mesenchymal stem cells exert significant radiation protective effect by enhancing the hematopoietic niche

BACKGROUND

Radiation induced hematopoietic failure was the primary cause of death after exposure to a moderate or high dose of whole body irradiation, causing increased challenge for nuclear or radiological treatment, so it is an urgent need to develop radioprotectors for attenuating hematopoietic damage caused by acute radiation syndrome (ARS). Given the excellent therapeutic effects and special benefits of mesenchymal stem cells (MSCs) in radiation damaged hematopoietic stem/progenitor cells (HSPCs) recovery and hematopoietic niche reconstruction, enhancing the hematopoietic niche with the radiotolerance MSCs can be an alternative solution to prevent and attenuate hematopoietic radiation damage, which needs to be studied.

METHODS

Here, we constructed MSCs modified with Damage Suppressor Protein (DSUP), a radiotolerance gene identified from tardigrade Ramazzotius varieornatus, and verify its radiation protection effect in HSPCs-MSCs co-culture model in vitro and radiation damaged mice model in vivo.

RESULTS

Our results showed that DSUP protein had no significant toxic side effects on the basic stemness properties and differentiation potential of MSCs, and significantly enhanced the radiation tolerance and DNA protection ability of MSCs. Compared with the control (CON) group MSCs, the DSUP modified MSCs after radiation damage suffered less DNA damage, preserved most of proliferation activity and migration ability. In the HSPCs-MSCs co-culture model, DSUP modified MSCs have significant protective effect on HSPCs by providing a functional hematopoietic niche after radiation damage. The DSUP group irradiated HSPCs exhibited more rapid recovery, the higher HSPCs ratio and better hematopoietic differentiation potential. In animal studies, pre infusion of DSUP modified MSCs reduce irradiated mice mortality rate, reduce hematopoietic failure incidence, and provide a protective effect against radiation injury by protecting hematopoietic microenvironment and promoting HSCs recovery. DSUP modified MSCs can be used as a radioprotector and existed significant radiation protection effect for ARS at doses below 7 Gy total-body irradiation (TBI) of X-ray in both immunodeficient and immunocompetent mice models.

CONCLUSIONS

DSUP modified MSCs may serve as a new radioprotector for ARS. DSUP modified MSCs could attenuate radiation damage of HSPCs and promote HSPCs rapid recovery as well as hematopoietic reconstruction by providing a more functional niche after radiation, thereby reducing the occurrence of hematopoietic failure and improving survival rate.

Interstellar space biology via Project Starlight

Our ability to explore the cosmos by direct contact has been limited to a small number of lunar and interplanetary missions. However, the NASA Starlight program points a path forward to send small, relativistic spacecraft far outside our solar system via standoff directed-energy propulsion. These miniaturized spacecraft are capable of robotic exploration but can also transport seeds and organisms, marking a profound change in our ability to both characterize and expand the reach of known life. Here we explore the biological and technological challenges of interstellar space biology, focusing on radiation-tolerant microorganisms capable of cryptobiosis. Additionally, we discuss planetary protection concerns and other ethical considerations of sending life to the stars.

Research presented at the 14th International Symposium on Tardigrada: progress in studies on water bears

The 14th International Symposium on Tardigrada took place in Copenhagen, Denmark from 30 July to 3 August 2018. Approximately 140 participants, representing 28 countries from five continents attended the meeting, and there were 58 talks and 74 posters of which 20 were selected for the Symposium Proceedings published in this special issue. The studies span phylogenomics, systematics, anatomy, morphology, reproductive biology, cryobiology, ecology, diet, microbial interactions and biogeography, taking the next step forward in broadening and deepening our understanding of tardigrade biology.

Radiation Tolerance in Tardigrades: Current Knowledge and Potential Applications in Medicine

Tardigrades represent a phylum of very small aquatic animals in which many species have evolved adaptations to survive under extreme environmental conditions, such as desiccation and freezing. Studies on several species have documented that tardigrades also belong to the most radiation-tolerant animals on Earth. This paper gives an overview of our current knowledge on radiation tolerance of tardigrades, with respect to dose-responses, developmental stages, and different radiation sources. The molecular mechanisms behind radiation tolerance in tardigrades are still largely unknown, but omics studies suggest that both mechanisms related to the avoidance of DNA damage and mechanisms of DNA repair are involved. The potential of tardigrades to provide knowledge of importance for medical sciences has long been recognized, but it is not until recently that more apparent evidence of such potential has appeared. Recent studies show that stress-related tardigrade genes may be transfected to human cells and provide increased tolerance to osmotic stress and ionizing radiation. With the recent sequencing of the tardigrade genome, more studies applying tardigrade omics to relevant aspects of human medicine are expected. In particular, the cancer research field has potential to learn from studies on tardigrades about molecular mechanisms evolved to maintain genome integrity.