Cytocentric Visionaries: Donald Phinney, Chair Department of Molecular Therapeutics, The Scripps Research Institute
Part One: Mesenchymal Stem Cells, as Healers, Aren’t So Selfless
Chair of the Molecular Therapeutics Department at Scripps, Dr. Phinney has almost 20 years of experience in the adult stem cell field and has been an editor of prominent stem cell journals. Here, Alicia Henn talks with Dr. Phinney about his latest publication in Nature Communications, ”Mesenchymal stem cells use extracellular vesicles to outsource mitophagy and shuttle microRNAs”[Phinney et al., 2015]. This conversation was edited for length.
Phinney and his co-authors reported that in response to oxidative stress, MSCs export damaged mitochondria to nearby macrophages, which recycle them for their own bioenergetics. The MSCs also export exosomes containing miRNAs that reduce the inflammatory activities of macrophage through TLR-7 signaling pathways. This benefits the nearby MSCs, and is also a mechanism by which MSCs may have their clinical effects on surrounding tissues.
Dalton in the Incubator: Gas Control in Semi-sealed Chambers
We are all familiar with how CO2 is infused into cell culture incubators to raise CO2 to physiologic levels and keep carbonic acid based media in the proper pH range for cells. However, managing a system for infusing other gases necessitates understanding how mixed gases work in a semi-sealed chamber.
Temperature, CO2, and pH in Cell Culture Media -
What Seems Best for Incubation is Not Always Best for Handling
Most, but not all, cell culture media contain carbonate-based buffers which work with elevated gaseous carbon dioxide levels in the incubator to stabilize cell culture pH (see figure). Carbonate-based buffers are present in vivo and so seem like an obvious choice for physiologically relevant incubation conditions. However, carbonate-based buffers can create non-optimal conditions for cultures during cell culture handling outside of the incubator. The critical cell parameters of temperature and carbon dioxide levels can affect carbonate buffered cell media.
Top 5 Cytocentric Publications of 2015
Overall, 2015 was a big year for moving cytocentric research forward. Some publications have stood out from the rest as impactful. The authors of these papers not only used cytocentric principles in carrying out their experiments, but their findings and language help describe a new scientific era of more physiologically relevant in vitro cell systems.
Oxygen regulates proliferation of neural stem cells through Wnt/beta-catenin signalling. Braunschweig et al. Molecular and cellular neurosciences. 2015;67:84-92.
This group found connections between physioxia and a non-HIF signaling pathway, the Wnt/beta-catenin pathway. Oxygen is a multi-functional signaling molecule in vivo and we predict that more pathways will emerge in the coming years outside of the HIF factors as more attention is focused on cells in a more physiologic context.
Cytocentric Visionaries: Randy Yerden, CEO BioSpherix
Part Four: A Trachea for Hannah
This post contains excerpts from an interview that Dr. Alicia Henn, Chief Scientific Officer of BioSpherix, conducted with Randy Yerden, Founder and CEO of BioSpherix.
In Part Three, we talked about seeing Cytocentric Principles in action in research. Today we talk about the incredible experience of participating in groundbreaking surgery to implant a stem-cell bearing manufactured trachea into a toddler.