Cytocentric Visionaries: Dr. Heather O’Leary

This is final part in a three-part series of blog posts containing excerpts from an interview that Dr. Alicia Henn, Chief Scientific Officer of BioSpherix, conducted with Dr. Heather O’Leary. In the third and final part of our interview, we sit with Dr. Heather O’Leary to discuss how room air oxygen conditions affect cell research.

In the last post, Dr. O’Leary talked with us about specific technical challenges in working with cells in low oxygen.  Here we talk about terminology for physiologically relevant oxygen studies and whether or not room air is “good enough.”

How appropriate is the term “hypoxia” when we talk about oxygen studies?

HAO: It’s challenging. It would be nice if there were better terminology, but I’m not sure what exactly that should be. Hypoxia isn’t exactly all-encompassing for what you’re talking about, but I don’t have a better word for it.

It would be nice to have a more specific terminology because hypoxia could be anything. We use it generally, but bone marrow is 1 to 4% and we know if we turned the oxygen up to 5%, we started to lose the effects. There is a very fine balance there of what the cells like, for lack of a better term, or where they are at least phenotypically consistent. At 5% instead of 3% oxygen, they start to look more like room air.

Here at the Cytocentric Blog, we try to take the cell’s point of view. What oxygen level do you think these cells would ask for, if they could?

HAO: I can’t say that, but I’d say they like 3% oxygen. We are doing experiments to go a little lower. We are going see how they feel about 1%. We are also looking for other phenotype differences to see where other phenotype switches may happen.

What effects would you expect to see in other types of stem cells?

HAO: My hypothesis would be that we would see changes in those that were phenotypically similar to what we have seen in HSC, based on their preferred oxygen tension. I think we will see some cell types that are more sensitive than others. You still detect functional stem cells when you harvest them in air, so clearly there is some sort of difference between the cells that are sensitive and the ones that aren’t as sensitive, for lack of a better term. I think most stem cells will show some sort of population that is sensitive to the oxygen tension or changes their level of differentiation.

How would you respond to people that say, “I’ve been handling cells just fine for years in room air. It’s good enough.”

HAO: I’d say “That’s true, but then we don’t know necessarily what we are looking at.” Even with the hypoxia, we aren’t mimicking all the cytokines/chemokines/factors that we are flushing out of the bone marrow. That alone, is probably enough to change the cells because you are taking them out of their native environment.

Until we have the technologies to completely in vivo image and tag cells to look at phenotypic markers as they really are, I feel like it is important to mimic their environment as best we can to really understand what is happening with them. It is hard to understand the different cell types without being able to manipulate them as they really are, in their natural environment and in their native state. We want our animal models and discoveries to be as accurate as they can with respect to representing the process or disease we are studying.

Do you think soon we will have release criteria that will include things like metabolic phenotype?

HAO: I think so and I think it is important because it changes so quickly and I think we use “metabolism” like we use “hypoxia” right now – as a global all-encompassing term. We don’t necessarily pinpoint and pick things apart, even for example at the levels of ox-phos versus glycolysis there is a lot of variability in there and small changes can make a difference in the phenotype and function of the cells. I think there is a lot of room there to change the vernacular to be more specific.

You used cyclosporine to mimic the effect of oxygen control, but do you think that cyclosporine might interact with other cell mechanisms?

HAO: I think that cyclosporine is mostly doing the inhibition of the Cyclophilin D, although I’m sure it will have off-target effects, but I don’t think that is necessarily the only mechanism with respect to hypoxia. Hypoxia is more multi-faceted and I would expect if we looked in a longer timeframe, we would see differences between the cyclosporine and hypoxia harvested cells.

What is the next step for your work?

HAO: We are interested in better understanding the steady state of the cells in hypoxia, and how the air modifies different subpopulations of cells. I’d like to find out more about the MPTP regulation and opening. That was really challenging for us to do, from a technical standpoint.

Thank you, Dr. O’Leary, for your time and insight. We look forward to seeing more exciting work from you in the future.

If you would like to be considered for a Cytocentric Visionary feature, please contact us here and tell us how your work in stem cell research fits the Cytocentric Principles.