Inhibition of mTOR induces a paused pluripotent state

Developers

Aydan Bulut-Karslioglu, Hu Jin, Jun S. Song, Miguel Ramalho-Santos, etc.

Description of the technology

Cultured pluripotent stem cells are a cornerstone of regenerative medicine owing to their ability to give rise to all cell types of the body. Although pluripotent stem cells can be propagated indefinitely in vitro, pluripotency is paradoxically a transient state in vivo, lasting 2–3 days around the time of blastocyst implantation. The exception to this rule is embryonic diapause, a reversible state of suspended development triggered by unfavourable conditions. Diapause is a physiological reproductive strategy widely employed across the animal kingdom, including in mammals, but its regulation remains poorly understood.

The authors of this technology found that the partial inhibition of target of rapamycin in mammals (mTOR), a major nutrient sensor and promoter of growth, induces reversible pausing of mouse blastocyst development and allows their prolonged culture ex vivo. Paused blastocysts remain pluripotent and competent, i.e, able to give rise to embryonic stem cells and live, fertile mice. Herewith, both naturally diapaused blastocysts in vivo and paused blastocysts ex vivo display pronounced reductions in mTOR activity, translation, histone modifications associated with gene activity and transcription. Pausing can be induced directly in cultured embryonic stem cells and sustained for weeks without appreciable cell death or deviations from cell cycle phase distributions. The paused embryonic stem cells display a remarkable global suppression of transcription, maintain a gene expression signature of diapaused blastocysts and remain pluripotent.

Thus, new method allows to induce paused pluripotent state by controllable inhibition of target of rapamycin in mammals.

Practical application

These findings speak about existence of a new pluripotent stem cell state corresponding to the epiblast of the diapaused blastocyst and indicate that mTOR regulates developmental timing at the peri-implantation stage.

This technology can be applicable in the fields of assisted reproduction, regenerative medicine, anti-cancer therapy, study and treatment of metabolic disorders and ageing.

Laboratories

• Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Center for Reproductive Sciences and Diabetes Center, University of California, San Francisco (USA)
• Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana (USA)
• Departments of Bioengineering and Physics, University of Illinois, Urbana (USA)
• The Centre for Phenogenomics (TCP), Toronto (Canada)

Links

Publications

• Bulut-Karslioglu, A. et al. «Inhibition of mTOR induces a paused pluripotent state." 540 Nature, (2016): 119–123.
• Behringer, R., Gertsenstein, M., Nagy, K. V. & Nagy, A. Manipulating the Mouse Embryo. (2013).