Regeneration Using Stem Cells
Earlier this year, I had breakfast with George Church, professor of genetics and director of the Center for Computational Genetics at Harvard Medical School. (Click here to read my profile of Church in the New York Times.)
A pioneer in developing DNA sequencing technologies, and in researching everything from epigenetics and microbiomics to synthetic biology, Church has co-founded or advises over 20 companies. He also has launched the Personalized Genome Project with a goal of sequencing the complete genomes of 100,000 volunteers.
When I asked Church what he was most excited about right now, he answered without hesitation: “I’m thinking a lot about using regeneration as the key to treatments and keeping people healthy.”
TR: You mean regeneration using stem cells?
Church: Yes, induced pluripotent stem (IPS) cells (see, “Growing Heart Cells Just for You”). This is where I’m putting almost all of my chips these days, because it combines many of my interests—genomics, sequencing, epigenetics, synthetic biology, stem cells. I don’t think people have fully appreciated how quickly adult stem cells and sequencing and synthetic biology have progressed. They have progressed by orders of magnitude since we got IPS. Before that, they basically weren’t working.
Is this because IPS cells are relatively easy to create and to engineer?
You can use them to reprogram genomes—not sequence them, but to reprogram them genetically and epigenetically. In other words you make the minimum changes it takes to get them where you want them to be genetically and epigenetically and then you program the cells into tissues.
What do you mean?
Let’s use stem cells in bone marrow as an example. They are easy to use and to get to work when you implant them in bone marrow. You might one day have three choices. You can have bone marrow from someone else that is matched to you, or that is from you, or bone marrow that is matched to you and comes to you, but is better than you. This better bone marrow might be [engineered to be] resistant to one virus, or to all viruses. It could have a bunch of alleles that you picked out of super centenarians, alleles that you have reason to believe are at least harmless and possibly helpful. So now you have choice, a patient who can take a good bone marrow that he might reject and you’ll be on immunosuppressants your whole life. Or you might use your own, or your own that might fix the cancer, or your own enhanced bone marrow. And you will be able to do that for almost every stem cell population. Some of them are a little bit harder to replace, though.
Does IPS really work to accomplish this regeneration?
We have good evidence that you can create an entire mouse from IPS cells.
Has this been done?
This has been done. They have used IPS cells to grow a mouse, and they made IPS cells from that mouse. They’re totipotent [able to make an entire organism], not merely pluripotent. We haven’t done this for humans for obvious ethical reasons, but we will do it. As far as I know the mice have done fine.