Steakholder Meets: The cell

Orit:
Welcome to Steakholder Meat, the Biweekly Twitter space show brought to you by Steakholder Foods. So today we want to explore the cultivated meat process with you from the biology point of view. So we created a set of five episodes that will be dedicated to this. We will start with the cell, then the cell lines, the growth, the differentiation into fat and muscle cells, and finally test texture and bio-inks. So in today’s episode, we will talk about the cell with our special guests, Diana and Igor I’m, Orit, the VP of Biology at Steakholder Foods, a leading player in the cultivated meat industry. Diana and Igor are researchers on the molecular biology team, and together we will review the different aspects of the cell, the source, the isolation, the growth, the characterization, and our challenges. So if you are interested in learning more about the scientific side of this exciting topic, join us and bring your questions. So if you are tuning in live and have any questions, please write them as a comment on our Q&A tweet and we will do our best to get your answer. Diana and Igor, welcome. I’m so excited to have your both here today to talk about the work we are doing here at Steakholder Foods. So first, we always start with a brief introduction. Can you please, each of you, tell me with a few words about yourself, how you got into food tech in general and what you do in your daily work?

Igor:
I think the lady can start.

Diana:
Thank you. Hi. Well, I’m very excited to be here. And as Orit said, my name is Diana. I graduated from Tel Aviv University in 2019, and now I hold a Master’s degree in biotechnology. And I was looking for an opportunity to use my skills and to contribute to something beneficial to society. So here I am, at Steakholder foods, and I’m at the Molecular Biology team. And on my daily work, I conduct genomic analysis experiments, proliferation and differentiation improvements, and charachtarization of the cell lines. That’s me. Igor?

Igor:
Yes. Hi everyone. I’m Igor. I hold a Master’s degree in biotechnology, and I graduated just about five months ago. And my research was focused on stem cells, basically. And I got into the food tech industry at Steakholder Foods in particular, because I was thinking about how we can use stem cells and this knowledge and everything I tried to learn during the Masters and what can we actually do with it, how we can make an impact using this knowledge. And that’s how I got into Steakholder Foods. So, Diana and myself are on the same team and basically we do very similar stuff. I work also with the stem cells and the cell lines and we try to enhance differentiation protocols and make the cells grow better, faster, stronger, make more fat and muscle and apply them to create cultivated meat in general.

Orit:
Thanks, Diana. And Igor. So let’s start with the topic of the day, the cell. Igor, you won, the first question is yours. So can you tell us about the cell? What is a cell and how do you characterize it?

Igor:
Sure, a cell. Basically is the very basic building block of all living organisms. So cells group together to form tissues and organs. And basically, our body is composed of billions and billions of cells. We have a lot cells everywhere. And just to give a few examples so everyone can understand what cells are, I think most people know what red blood cells are. These are the cells that carry oxygen to all tissues in our body through the blood vessels. Another example is white blood cells. They belong to the immune system and these are the tiny soldiers of our body that fight bacteria and viruses and eliminate them. Another example of cells are muscle cells that are able to contract and relax and by that allow motion of the tissue. Another tiny example is fat cells, which store energy in the form of fat. So when we all gain a little bit of weight, we just basically increase the size of the population of fat cells in our body. Basically, we have a lot, a lot of different types of cells in our bodies. Each cell has its own shape, its own size and a specific location in the body and it performs a specific and unique function. Can you all hear me?

Orit:
Yes, sure. Great.

Igor:
Yeah, I’m just making sure that I’m not talking to myself.

Orit:
No, you are not.

Igor:
So we have a lot of different types of cells and cells are not unique to humans. Actually, all living organisms are composed of cells, including plants and yeast and bacteria and animals and all other living things were all composed of cells. So just in general, just for you to get an idea what cells are, I hope it’s clear.

Orit:
Yes, I think it’s very clear. So to summarize, cells are the basic units of living organisms located in different tissues in the body and each of cell type has a unique characterization. But I guess there are many different types of cells, like progenitor cells, stem cells that everybody is hearing that leads us to our next question. What is a progenitor or stem cell?

Igor:
Yes. So stem cells in general, in many, many tissues in our body, there is a small population of stem cells. And unlike mature cells that perform a very specific and unique function, stem cells are a bit different. They possess two very interesting abilities one of them is their ability to divide basically indefinitely in their own native tissue. And so they can divide more and more and more and keep their population going. And another very interesting characteristic is their ability to mature and acquire a specific function. And this process of maturation is called differentiation. So for example, stem cells in the muscle tissue are able to, upon receiving specific signals, they’re able to mature and fuse to an existing muscle and increase the mass of the muscle. So they’re able to divide and then upon a specific signal, they differentiate to the muscle. I hope it’s clear. So basically, stem cells are able to divide and they are able to differentiate. And these are very important characteristics. And we will talk about why it’s very important and interesting for us, for our industry.

Orit:
So tanks Igor. So unlike mature cells, stem cells do not perform a specific function, right? But they have the ability to divide and mature into different specific cell types to perform specific function through a process called differentiation. But how can you identify the cells? How can you characterize the cells, the stem cells or the mature cells and cells you got in culture?

Igor:
Yeah, so basically, each and every cell type produces specific proteins, a set of specific proteins that allow this specific shape, size and function of the cell. So we can conceptualize this set of proteins as the specific signature of a specific cell type. And different cell types have different sets of proteins they produce. So each and every cell type has its own signature. And we have the technology, not only us, a lot of this technology has been around for quite a while, for decades. It has been improving over time. But basically, this technology allows us to examine this signature and confirm that the cells we think are the cells we think they are. I hope it’s clear. It’s quite difficult to explain without giving a specific example of a specific technology.

Orit:
So maybe you can give us an example of how we characterize the muscle cells or the fat cells.

Igor:
Yeah, so with muscle it’s very simple. I’ll explain in a bit why it’s simple with the muscle, that the way we can characterize it and confirm that our stem cells are indeed muscle stem cells is. For example, we can use microscopy and we have the technology to stain specific proteins and then we stain them and, when we look at them under the microscope, they generate a specific fluorescent in a specific color. So if we detect this color, it means that the cell is what we think it is, because we stained it with a specific marker. So basically we stain a marker and then if we identify this marker, we confirm that the cell is what we think it is. It’s quite complex to explain. With muscle stem cells it’s quite easy because we can trigger them to fuse and form muscle fibers. And this is something we can see very clearly under a light microscope, without any staining, without any specific or complex technology.

Orit:
Thanks, Igor. So, I just want to remind you that if you have any questions, please write them as a comment on our Q&A Tweet and we will do our best to get your answer. So, just to summarize Igor, we can characterize the cells easily, from the outside to inside by different methods. And now we understood what cells are, how to characterize them. So now we would like to know what is the source of the cells to generate cultivated meat? Diana, can you help us with this question?

Diana:
Sure. Well, the source of the cells is the very first step of the cultivated meat process. So during this stage, a sample of tissue is ethically collected from an animal. The process is administered in the most humane way possible in order to minimize the animal’s discomfort. After the collection of the cells, the tissue will be placed in culture, enabling the stem cells to be isolated and to grow. To generate bovine cells in secular food using Mesenchymal stem cells that are derived from the umbilical cord of newborn calves or stem cells of the edible tissue, or stem cells from the muscle, thus avoiding the use of invasive procedures to the animal.

Orit:
Amazing. Diana. So we have a first question from the audience why is it relevant to isolate the cells from different tissue?

Diana:
As Igor said before, every cell has a specific characteristic. So some cells are more prone to differentiate into specific cell type, meaning that, for example, cells that were collected from muscle tissue are prone to differentiate into muscle. And the same thing happens with fat cells, which came from fat tissue, and they prone to differentiate into fat cells.

Orit:
Amazing. So, according to the type of cells you want to use in the lab or to differentiate either in fat or muscle cells, stem cells are isolated from different parts of the animal. So once you average the tissue, what are the methods used in the lab to isolate the stem cells?

Diana:
Well, as we said, we isolate the cells from tissues, so I’ll start with the tissue. In general, a tissue is a biological organization level of a group of cells that have stimulus structure and that function together as one unit. Those cells are connected by an extracellular matrix that is fundamentally composed of proteins like collagen and elastin and polysaccharide. Typically, animal tissues are grouped into four basic types: connective tissue, muscle, nervous and epithelial tissue. And now, if we go back to the question, there are a few ways for cell isolation that we use for establishing a cell line. One of them is called exponent sculpture. In this technique, a piece of tissue is used as starting material for the whole cell culture. For example, a small piece of tissue is taken, then it cuts to smaller pieces that are safety placed on a cultured dish that is filled with an appropriate medium, like an intrinsic solution. Then the small explants are incubated in under controlled conditions until the cells just emerge out of the explanation. And at this point, those cells are collected and did it again and culture for proliferation and extension, which means that they increase the number of cells. And the other way we used in the cell isolation is called about chemical dissociation, in which the cells are emptymatically released from the tissue. In this method, the tissue sample is treated with a specific enzyme or enzymes that they test the extracellular matrix, the connective tissue itself, that holds the cells together and that allowing the cells to dissociate from the tissue. And again the cells are collected. And following the step translation, we perform an enrichment of the culture that gives us a homogeneous desired cell line.

Orit:
Wow, great. So we are able to isolate the cells from different tissues with different techniques. So you mentioned earlier that you are expanding the cells in control conditions. Can you please share how you culture these cells and in which conditions?

Diana:
Of course, to culture the cells, we feed them in a monolithic to delayer in culture vessels of different sizes. Those vessels are filled with a growth medium that supplies all the essential nutrients like amino acids, carbs, vitamins, minerals and of course, growth factors. Then, the cells are placed in incubators that maintain optimal temperature, humidity, CO2 levels and atmospheric pressure. There, the cells are incubated further to proliferate and produce more cells. And when the culture reaches specific density, it is subdivided, meaning that some parts of the cells are transferred into a new culture vessel with a fresh culture medium. The other part can be taken for characterization or long time preservation.

Orit:
Talking about longtime preservation, we have a question from the audience; how we preserve the cells for a long time run?

Diana:
Well, we can preserve the cells for an extended period of time by just by cooling the samples to very low temperatures, way above the minus zero. The cells are frozen, there are well established methods for that and are stored in liquid nitrogen. Under these conditions, the cells can be stored for decades without any harm. And if we need them, we just bought them and they continue to grow.

Orit:
Amazing. So we are controlling the process from the beginning until the end. But how do we know that the cells are safe, are safe and remaining safe during all the process?

Igor:
It’s very important to understand that basically every single thing we eat, we consume is made of cells. All the meat we eat, all the fish we eat, all the seafood we eat, all the seeds, fruit, vegetables, every single thing we consume is made of cells, and a lot of them. And we have been consuming cells for quite a while. So the cells we grow in the lab under very controlled conditions and under very specific conditions are as safe as every other cell type we consume or have consumed in our lifetime. And one of the advantages of growing cells under controlled conditions is that we don’t add any antibiotics. There is no bacteria like a lot of meat and fish and seafood, it contains a lot tons of bacteria that we consume all the time. Cells we grow at the lab, they don’t have any of that. So they are as safe as any other thing we have consumed in our life and maybe even more, I don’t know. Time will tell, but they should be as at least as safe.

Orit:
Amazing. You are answering for many questions from the audience altogether. So another question regarding is there a way to duplicate cells infinitely, meaning that eventually animals will no longer be needed?

Igor:
It’s a complex question. The short answer is yes. The longer answer is it’s complicated and complex. But we are getting there and we are not only our company, but many different companies and laboratories around the globe and try to develop protocols and ways to grow cells indefinitely. There are specific types of cells that possess the ability to grow indefinitely also at the lab. sorry, can you repeat the question? I forgot what I was talking about.

Orit:
Yes, I can. Is there a way to duplicate cells and definitely so we won’t need to use or to arms the animals?

Igor:
Yeah, sure, sorry. We just need to culture the right type cells and we need to provide them with a specific medium, with a specific liquid in which they grow that will maintain this indefinite division. It is possible, it takes time to examine all the components needed for this formulation, but it is possible. It is possible. It takes time and effort and I assume we will get there and also both us and other companies.

Orit:
Okay, we have more questions from our audience. So how do you foresee the future of the food tech industry over the next few years? Igor Diana?

Diana:
Well, we know that the demand for meat is increasing year over year and it’s really leading to some issues like defrustration and the overall cost of the livestock, of growing livestock keeps increasing. So we hope that cultured food will address some and more of these issues.

Orit:
Amazing. Diana, we have a lot of questions and another, I think it will be the last question, how you can have layers of fat or muscle cells?

Igor:
What do you mean?

Orit:
To generate a full piece of meat.

Diana:
We print them.

Orit:
Amazing. At Steakholder Foods. We developed our own printer and we are able to print the cells and to choose the ratio between fat and muscle cells. But please follow us regarding our printer. It will be one of the topics soon that we will discuss. So this was our last question for today, and I hope you all enjoyed this space as I did and that we were able to help you to understand more about cells. I look forward to the next biology space that will be about cell lines. Special thanks to Igor and Diana. Really thank you for your help, for your description of the cells. I wish you all a great rest of your day, a great evening or a good morning.