Cytocentric Visionaries: Roger Rönn

This is a five-part series of blog posts containing excerpts from an interview that Dr. Alicia Henn, Chief Scientific Officer of BioSpherix, conducted with Roger Rönn, who is finishing his PhD at Lund University. Our conversation on working in optimized conditions for hematopoietic cells was edited for brevity and clarity.

In the last post, Part Four, Roger told us about the benefits of physiologic oxygen for HSC in vitro. Today, we discuss the practical aspects of carrying out such experiments.

What do you think is the toughest part of carrying out experiments in a protected, low-oxygen environment for your cells?

RR: We have a hypoxic incubator. One of the biggest problems is that you still need to expose your cells to unphysiological conditions. Since the goal is to get as close as possible to physiological conditions, the method I used, while being better than our standard culture conditions, can still be considered the second best thing.

I am preconditioning my medium for a long period of time before the media is allowed to touch the cells. That is absolutely necessary because the media needs a long time to equilibrate to the new oxygen tension.

There was a paper by the Broxmeyer group that showed that even a short time of supraphysiological O₂exposure can have a huge impact on the HSCs in cord blood samples.

The same work that was discussed at Heather O’Leary’s talk at ISSCR where we met you? ^[1]

RR: Right. The Broxmeyer Group’s paper showed that they get such a huge reduction in functionality with just a few minutes of O₂ exposure, so any way to do this in a non-changing environment would be a great benefit.

When we harvest our cells that we generate from pluripotent stem cells, it is a whole-day process. We have to singularize the cells, filter them, spin them, count them and then stain them for FACS. If they go to transplant, they still sit on ice in 21% O₂. I run them through a gauntlet of things that they don’t like, while also in 21% O₂. It takes me four hours until they are ready to go into the host.

That entire process, I can’t do that in hypoxia conditions similar to what the cells were cultured in. Any system that would minimize the changes of environment would be preferable.

Thank you for your sharing your experiences and thoughts with us and our readers and all the best to you as you continue your important work.

If you would like you and your work to be featured in the Cytocentric Visionary series, please contact us and tell us how your work fits the Cytocentric Principles. .

1. Mantel, C.R., et al., Enhancing Hematopoietic Stem Cell Transplantation Efficacy by Mitigating Oxygen Shock. Cell, 2015. 161(7): p. 1553-65.

Roger Rönn interview: Part 1, Part 2, Part 3, Part 4, Part 5