iPSC breakthrough: making ALS-like motor neurons that predict reality

1:47:41>> now we can start talking about the paper that I want to talk about. The paper has to do with IPS-C's. These are pur potent stem cells. >> Okay. >> Okay. >> These are induced puro potent stem cells. In 2012, the Nobel Prize went to John Girden and Shina Yamanaka for the discovery that mature cells can be pre can be reprogrammed >> to become stem cells. Stem cells are stem so stem cells are cells that um have not differentiated into like you know skin cells or blood cells or bone cells or whatever. They are a clean slate. They don't have a specialization. They're like you in high school before you went into college and then got a

1:48:22major and now you're stuck at whatever you know path of life, >> right? And what induced pur potent stem cells do >> is now we're able to reprogram someone who's let's say been through college and a PhD >> pre-program their brain so that now their brain is back in high school and they can be something totally different. Just to quickly note like that's like a phenomenal like in and of itself this which is from the 2012 uh Nobel Prize that concept is really powerful because effectively what you're saying is >> uh I'm in the college high school college analogy if I get to age 45 and the world has changed and my industry

1:49:02has been replaced by insert whatever uh I can just be almost reset to being 1920 >> and retrained. again. >> Yeah. >> Uh without like with with a with a substrate that is not my 45year-old mind, but it's my 20-y old mind. >> Yeah. Yeah. And this is really amazing for biomedical research because one, we don't have to rely on embryionic stem cells. >> Yeah, that's a good point. >> Right. Because embryionic stem cells are really where the stem cells are, right? Because as an embryo, you can imagine from an egg and a sperm, that egg is just like a single cell. That single cell is now becoming my nails, my my lungs, my skin, my muscles, my neurons.

1:49:42Right. So somewhere that single cell becomes a ball. >> Yes. >> And that ball has a bunch of embryionic stem cells. Each cell now defines I'm going to go become the eye. I'm going to go become a hair cell. So on and so forth. With this technology, we don't need embryionic stem cells. We can take skin cells, graft them, put them with a genetic cocktail, and then they are going to become stem cells on their own. Right? It completely changes the landscape and that's why they won the Nobel Prize in 2012. That makes sense. Very much deserved because it's changed biomedical research not just for ALS but like countless other diseases. Okay. >> Um >> now as you can imagine 2012 this is a pretty old technology.

1:50:23>> Sure. >> Right. >> We have tried to use it for ALS. There was this consortium called answer ALS. They got a thousand lines from ALS patients and they tried to make lines of stem cells >> but they observed the same problem which is that the drugs wouldn't like the same drugs that don't work in clinical trials >> they'll work in these in pluropotent stem cells >> they will >> they will so >> interesting >> they were still missing something >> right >> right it's like these stem cells were not mimicking >> ALS motor neurons M >> they were they were trying right we got we got the stem cells from ALS patients

1:51:04that have the disease but when we make >> them into stem cells when we get the donor skin cells from the ALS patients when we try to make them into stem cells they don't mimic the disease that the patient has >> and that's the whole point >> that's the whole point >> so what what's going on >> oh which which is interesting because >> anyway that you see you understand what I'm saying though right >> yeah because like in my head like intuitively I'd be like oh well If you're taking my my skin I let's say I have I have ALS in this example. You take my skin cells uh and then you try to reprogram it. >> Yeah. And I'm I try to make that into a motor neuron, >> right? The problem is the motor neuron is not my body's stuff which has >> Yeah. It's just like a normal motor neuron. >> Neuron, right? Because it's been

1:51:44>> reprod but the whole point is I want to make >> right >> a model of ALS in a petri dish. Correct. That I can then mess around with >> which currently we just can't get from the boilerplate out of the box induced p stem cell and that is where we get to our study in 2025. It's an in vitro model of sporadic ALS. It was a nature neuroscience large scale drug screening. >> And what they did was actually figure out how to make this happen. Okay. >> How to make petri dish >> level Yes. >> ALS that I can mess around with in a lab and really try to understand what drugs would work and what drugs wouldn't. Right. Mhm. Mhm. >> Um it's out of the University of

1:52:26Melbourne and the University of Queensland. A lot of like Australian universities. >> There's there's quite a few institutions that were collaborating on this. >> That's right. So what they did different is the following. So they got 100 patients with um sporadic ALS. They got 11 patients with familial ALS. They got 25 healthy controls. They got skin cells from the dermal fibroblasts. that they extracted from skin biopsies from these patients and from these 25 controls >> and they used something called non-integrating episomal vectors. So usually when we try to make stem cells like pluropotent stem cells from

1:53:06whatever donor like skin cells that we got I need to I need to change the genetics of that skin cell to now forget everything about being a skin cell and go back to being a stem cell. Right? Usually when what we how we do that is we um use a retrovirus. >> Okay. >> So a virus that has a piece of RNA. The RNA goes into the cell that becomes reverse transcribed into DNA. The DNA then goes and gets mixed in with the native DNA of the cell. With these specific non-integrating eposomal vectors, this is DNA that that just goes into the nucleus and hangs out. >> It doesn't get inserted into the chromosome of the cell. And what that

1:53:46does is prevent any random, you know, like offtarget stuff from happening. >> It's exactly what we want. Exactly. >> Yeah. It's just it's not messing with anything >> that's already there because the cell is already in this sort of it's from an ALS patient. So it already has the mutations, >> right, >> that are causing ALS. We don't want to mess with that because we want to replicate the ALS in my petri dish. >> So if I want to reprogram the cell to become a motor neuron, I just get my DNA. I put it in the nucleus and I just have you hang out. Do not go inside the house. >> Just hang out. >> Yeah. Yeah. Yeah. Okay. Okay. Okay. Because previously the retrovirus insertion >> Yeah. It would insert >> and then >> and then that changes whatever is

1:54:27happening inside the house. >> And because this is such a comal problem, we have no idea. We don't know. >> Yeah. We don't know what happens. >> But now we have total control. We're trying to have total control over each of the sort of second and third order steps that happen after we introduce it into the environment. >> Exactly. Yeah. And they did a lot of other other stuff that I'm not going to totally get into, but like they the way that they um >> grew the stem cells, they actually withdrew a bunch of growth factors that would prevent artificial masking of this phenotype of ALS because we want that phenotype to actually happen. They also like >> cultured it under strict 5% oxygen, which is this hypoxic condition that happens in the spinal cord. Yeah.

1:55:09>> So, it's something that you want to mimic when you want to make modern neurons that are um like ALS. >> So, we remove stuff that would potentially make it so that the thing would like the system would make it go away and and we also created the environment that is almost identical to the environment that exists >> to remove again any possibility >> that we're missing the mark in terms of the in like the variables that need to be present in order to generate the results we're looking for. with this new in lab they' be able to basically replicate it in a petri dish. >> Yes, we want ALS motor neurons in a petri dish. >> Right. And finally the resulting purity that they got it was exceptionally pure motor neurons 90% were coexpressing the

1:55:50the gene that that we wanted. Okay. Um very low contamination. So there's not that many astroytes. There's not that many microglea. They're all motor neurons and they're all they all look great. >> This is a Okay. Okay. So this this this is a very big deal. >> Yes. So finally we might have our ALS in a petri dish. >> Yes. >> And now we can start doing preclinical trials in our [clears throat] petri dish >> with some confidence >> that it might work >> at the clinical stage. >> The point here is we're we're saying this uh ALS in a petri dish is going to increase the conversion rate of preclinical targets to those that actually can make it into clinical

1:56:30trials. M because we are basically saying we're basically recreating the environment that would be an actual human in the trials not using the rodent mouse rat model which can work in a lot of other cases. Yeah. >> But just in this one it does not. >> Exactly. >> Okay. Yes. >> Yeah. And when they created these um when they created these motor neurons in the petri dish those motor neurons would exhibit the same kind of damage that we got in ALS. they they came up with this metric called the lethal day 50%. So it's the exact day um when the total length of the neurites degrades by 50% the maximum peak length. So it's like imagine like you made the motor neuron

1:57:11and then you like press play and then you know because of degradation it's going to get shorter and shorter. >> They came up with this metric that metric was correlated and this is this is kind of the nail in the coffin that we have replicated in the petri dish. It's kind of an unfortunate metric, but at the same time, it's a lot of hope for the future because here's what they did. That metric >> is correlated with the actual clinical patient survival time.