Frozen Skin Cells Could Create A New Future For Endangered Northern White Rhinos

Speaker 1: 00:00 San Diego researchers are making progress on a long running plan to revive a nearly extinct rhino species to rhino births this year were important steps KPBS environment reporter Eric Anderson recently checked in on the newest baby at the San Diego zoo. Safari park Speaker 2: 00:20 future is a month old baby and already about 200 pounds. During a recent visit, she was far more interested in playing with a plastic tub and the fact that she's playing a role in a critical rhino recovery effort. Futures mom, Amani, and five other females were brought to San Diego in 2015 to be surrogate moms for Northern white rhinos. Only two Northern whites are still alive and neither can breed. Speaker 3: 00:47 This is an animal that will be extinct in our lifetime. Speaker 2: 00:51 Gene Loring is pioneering research that'll play a crucial role in the recovery plan. She's helping turn a dozen Northern white rhinos, skin cell samples into pluripotent or adult STEM cells, Speaker 3: 01:03 so we have a total of nine now in the freezer. Speaker 2: 01:08 Those STEM cells lines have the potential to become any adult cell in a rhino's body, something that's only been done before with mice. Loring hopes to eventually create rhino sex cells opening the door to creating a Northern white embryo. Speaker 3: 01:22 We are seeing the first signs of development into sperm and eggs that they're precursors to sperm and eggs. Those are called primordial germ cells Speaker 2: 01:34 in a small lab at the San Diego zoo, Safari park, Marissa karate is helping draw up the scientific guidebook that'll show researchers the path from skin cells to rhino embryos. A lot of that work is just that work. It's routine culturing of cells. Karate's team adds different things to the cultures to see what pushes the cells down a particular path. Speaker 4: 01:56 We give them the signals that we'll tell them to turn into whatever cell type we want so it can be giving them growth factors or it can be using specific chemicals that will turn on or turn off different pathways. In the cell cycle, Speaker 2: 02:09 karate was introduced to the project and gene Loring's lab and she was drawn in by the chance to help a species that is so good close to extinction. Speaker 3: 02:18 This is an active active culture of this STEM cell. You constantly feed it, you keep it active. Speaker 4: 02:26 We feed them every 24 hours. So if somebody is here seven days a week, if we don't feed them that frequently, that growth factor that makes them maintain their STEM cell state will break down. It's heat sensitive. Speaker 2: 02:38 Those daily chores are occasionally rewarded. Karate pulls up a video that caused quite a stir recently. This collection of STEM cells is pulsing, actually expanding and contracting in a Petri dish. Speaker 4: 02:52 So these are just responding. There's no pacemaker, so there's, they're not in sync as they would be if they were an actual heart. But yes, these are cardiomyocytes from Angela Angelica, Speaker 2: 03:00 Angelina who was the last male Northern white to live in San Diego. Developing those fledgling heart cells gives hope that sperm and eggs are not far off. I mean a Northern white embryo can be implanted in one of the zoos, six surrogates. Zoo geneticist, Oliver riders says the cloning of Dolly the sheep, and then the subsequent STEM cell advances have opened a door. Speaker 5: 03:27 And if we can make rhinos, cells have babies and we can reconstitute a functional breeding population of Northern white rhinos, we can take a species that is functionally extinct and return it to its habitat. Once that's secure, Speaker 2: 03:46 writer is standing in the San Diego zoo's frozen zoo. These nitrogen cold freezers hold genetic material from thousands of animals, some endangered, some not. Speaker 5: 03:57 There's a great need to expand this effort on a global basis through regional centers and centers in different countries. Speaker 2: 04:05 Ryder says this seed bank of cells idea is catching on and he thinks it's vital for the future of Northern white rhinos and possibly other species. Technology being developed in San Diego with the rhinos could have applications for other animals. Speaker 5: 04:21 I have a constant sense of the March of time and the grim Reaper of species extinction, Speaker 2: 04:29 but science writer says could be the key to undoing some of the manmade harm that's driving plants and animals to the edge. Speaker 1: 04:38 Joining me is KPBS environment reporter Eric Anderson. Eric, welcome. Thank you, Maureen. Since there are a couple of white rhinos still alive, why aren't researchers attempting to clone the rhinos? Speaker 6: 04:51 I think that technology is just as complicated and just as complex and has a whole different set of problems connected to it. They've kind of chosen to go a slightly different route, which is turning these frozen skin cell samples that they have in their frozen zoo, uh, into STEM cells and then turning those STEM cells into sex cells, which will allow them to create the embryo. I think that, uh, has a much more realistic chance, uh, of realizing success. Speaker 1: 05:20 The idea is to take these STEM cells, have them develop into rhino sex cells and in that way create a rhino embryo, which can be implanted in another species of rhino. Speaker 6: 05:32 Yeah. The, what they've described to me is what they do is they take the cell and they basically a race, the memory of the cell, like, um, it's a skin cell now, but they say, look, we're going to erase the memory. We're going to use a combination of viruses and some other agents that, that do that and roll back the clock on this cell until it becomes a, what they call a pluripotent STEM cell, which is a STEM cell that can become any cell in a rhino's body. Once they get to that point, then they want to guide the cell to become a, a gamut, a sex cell, a sperm and an egg. Once they get to the point where they have a sufficient supply of eggs and sperm, then they can fertilize those in the lab and then implant them into a Southern white rhino. Speaker 1: 06:13 Has there been any success in any species in producing an embryo from STEM cells? Speaker 6: 06:19 Uh, yes. Um, in fact a Japanese researchers have done this successfully in mice. It's obviously a lot easier to do in mice because the typical lifespan of a, a laboratory mouse is about seven months. So they go through that whole cycle a lot quicker. You can do it more often. But yes, they've had success doing this, uh, with mice tissue they've implanted and uh, an embryo and that embryo has come to term and become a baby mouse. Uh, the problem with rhinos, uh, not only is, uh, the animal bigger, the timeline is much bigger. Um, once a rhino gets pregnant gestation is uh, you know, 16 to 18 months. Um, so it's not the kind of thing you're going to be doing, you know, every, every seven months or a couple of times a year. Uh, it's something that you have to do over time. So the timeline is a lot longer just like the animal is Speaker 1: 07:08 just about how long has this research project been underway? Speaker 6: 07:11 It's been underway since about 2015. That's when they first brought these six, uh, Southern white rhinos to San Diego to be surrogates for the critically endangered Northern white rhino. Speaker 1: 07:22 And apparently if this effort is successful with the Northern white rhino, it sounds as if researchers are hoping to revive other extinct species. Speaker 6: 07:32 Well, if it becomes proven technology. So if they are successful in doing what they want to do and they create a Northern white rhino that's carried a term by a Southern white rhino mom, uh, you know, that's, that's putting a member of this species back on, on the planet. There are only two currently living, both of them females, neither of them capable of breeding. Um, so you're putting a brand new rhino of the same species on the planet and you can replicate that with the other surrogates. But yes, if they do it with rhinos, it opens the door to doing it with other species. Now, there are some complications. One thing about the rhinos is they have enough genetic variety in the cells that they have frozen. They have 12 individuals, uh, that they're using currently and they provide enough genetic diversity so that if a small herd has created, uh, that herd can be self sustaining. Not all of the cell samples they have from endangered species have enough genetic diversity and stories. So it's, it's a little bit more difficult to do, but it does open up the possibility that yes, you can do this with other species. If you're successful first with these rhinos, Speaker 1: 08:44 okay, so let's go speed forward into the future. And let's say they do create a herd of Northern white rhinos in this way isn't the reason that these are extinct in the first place because their habitat has vanished or can't support the species anymore. Speaker 6: 09:02 It wasn't entirely habitat based. Why these rhinos were in trouble in the wild. Uh, it was much more closely related to human activity. And if you can control the human activity and you can put them in an environment where they'll thrive, um, and you, they have the genetic diversity, uh, and the numbers to support a small herd, theoretically you could reconstruct that species into a, you know, a large functioning herd in the wild. I think there are some questions out there as to whether or not that point will be reached. Maybe the herd of Northern whites that you end up having are in captivity because they need to be protected because they're so rare. But it's possible because the habitat does at this point still exist. Speaker 1: 09:44 Okay. Back to now. And this research is ongoing. When do they hope that they may get an embryo? What is the timeline for that? Speaker 6: 09:52 I think there's still a a some time away. Um, they could have a breakthrough in the next year, uh, that might bring them close to that. But if you look at the other half of the equation, not the stuff that's going on in the lab, but the stuff that's going on, uh, with the, the six rhinos that the zoo brought in from South Africa, uh, they still have to train them. They want all of, all six of those rhinos to be impregnated by artificial insemination and carried a term. So far, only two of the six have done that. All six have that done. Uh, then they're ready to try with the Northern white embryo. It's complicated. Right. But the timeline means that that's probably gonna take a, a number of years to do, maybe four, maybe six, maybe eight years to do. Speaker 1: 10:34 Okay. Well, I've been speaking with KPBS environment reporter Eric Anderson. Eric, thank you. My pleasure. Speaker 7: 10:55 [inaudible].