Cultured meat is changing the world⁉-Genome editing and the future of meat

Benefits of artificially cultured meat

On June 23, 2021, Future Meat Technologies, based in Rehovot, Israel, announced the opening of the world’s first artificial cultured meat plant [1]. The plant can produce 500 kg of cultured meat per day, equivalent to 5,000 hamburgers, according to the company’s CEO, Rom Kushuk. Moreover, the plant is remarkable for its capacity to generate meat with significantly lower greenhouse gas emissions, land use, and freshwater consumption compared to traditional livestock farms. It is anticipated to address environmental issues related to meat production. This article focuses on lab-grown meat, explaining what it is and how genome editing is applied in its research.

What is artificially cultured meat?

Artificially cultured meat, also known as cultured meat or clean meat, is meat that has been artificially produced. It is defined as muscle cells extracted from a living animal with minimal invasion, nourished, and cultured to develop into muscle tissue. This tissue is biologically identical to the meat tissue that is the main component of the meat we normally eat. In other words, artificially cultured meat does not create meat components from scratch but instead artificially cultivates animal muscle cells outside the animal’s body to a size that can be eaten by humans. So, what are the benefits of artificially producing meat using this method?

Artificially cultured meat is revolutionizing the meat market

Artificially cultured meat has the advantage of maintaining an environmentally friendly supply to meet the rising demand for meat. The global population, especially in developing nations, is projected to reach 8.5 billion by 2030 and nearly 10 billion by 2050 [2]. In response to this trend, there is a steady increase in demand for meat. It is expected that annual global meat consumption will climb from approximately 317 million tonnes in 2016 to surpass 500 million tonnes by 2050 [3][4]. To meet the growing demand for meat, humans have tried to increase productivity by breeding livestock and improving breeding methods and feed. However, meat production requires significant resources. According to a 2010 study, the water footprint for producing 1 kg of meat is much higher than that for vegetables and fruit, especially beef, which requires 15,415 liters of water [5]. In addition, livestock production requires not only water but also significant amounts of land and fuel for transportation. Even though an estimated 130 million birds and 4 million pigs are slaughtered for meat every day worldwide, it generates a significant amount of food waste at the point of consumption. Against this backdrop, artificially cultured meat has gained attention in recent years as an alternative to conventional meat. Artificially cultured meat offers several advantages:

(i) efficient use of space and resources, with low water and feed requirements;
(ii) elimination of the need for animal slaughter;
(iii) reduced emissions of harmful substances such as CO2 and methane that are typically associated with livestock production.

Producing meat closer to the place of consumption can reduce the amount of toxic substances produced during meat production, processing, and transport, as well as the amount of methane emitted by cattle. Artificially cultured meat has the potential to overcome many problems in conventional meat production. Some foreign countries have already granted marketing authorization for artificially cultured meat.

Artificially cultured meat and CRISPR

Here, we would like to introduce an example of how genome editing technology, particularly CRISPR/Cas9, is used in artificially cultured meat. CRISPR/Cas9 is the current leading technology for genome editing, developed by Emmanuelle Charpentier and Jennifer A. Doudna. CRISPR/Cas9, which is called a third-generation genome editing tool following TALEN and ZFN, manipulates trait expression by cutting the target DNA sequence-specifically and deleting (knocking out) the target gene. Furthermore, by utilizing the repair mechanism that accompanies DNA breaks, it is also possible to express the desired gene by introducing donor DNA from outside. As previously mentioned, artificial cultured meat is based on animal muscle cells and tissue culture. Muscle cells can be cultured by providing them with growth factors that promote cell proliferation and differentiation, as well as a favorable medium for cell growth. The challenge in producing artificially cultured meat is how to enable rapid cell growth.

As an answer, there are two possibilities:
① Accelerate the growth rate of muscle cells themselves ← “Improve the internal mechanism for growth”
② Improving growth factors and culture media to be more efficient ← in “Providing a desirable environment”

Several companies are working on each method to achieve these two goals using genome editing technology using CRISPR/Cas9, and I will introduce one of them one by one.

UPSIDE Foods (formerly Memphis Meats)

UPSIDE Foods is a startup established in 2015 by cardiac surgeon Uma Valletti and biologist Nicholas Genovese [6]. The company is based in San Francisco, California, USA. UPSIDE Foods’ technology utilizes CRISPR/Cas9 to modify muscle cells and produce artificially cultured meat. According to documents from the Patent Cooperation Treaty [7][8], CRISPR/Cas9 is used to inactivate the ‘Rb gene’ in muscle cells, which arrests the cell cycle. This promotes cell cycle progression and also inactivates the ‘p15 gene’ and ‘p16 gene’, which suppress the expression of telomerase, a protein involved in cell life extension. The artificial cultured meat produced by UPSIDE Foods can be classified as one of Japan’s ‘genome-edited foods’ because it does not involve the insertion of genes.

Core Biogenesis

Core Biogenesis is a French startup founded in 2020 by two young researchers, Alexandre Reeber and Chouaib Meziad, with three platforms: cell therapy for neurodegenerative diseases, development of growth factors for cultured meat production and mRNA production, and development of enzymes for mRNA production [9]. The cultured meat industry has taken notice of them because they edit the genome of the growth factors in the culture medium, not the muscle cells they cultivate. According to research, growth factors are the most expensive media used for cultured meat growth [10]. However, by adapting CRISPR/Cas9 genome editing to plants that produce growth factors, they can be produced 25 times more efficiently than before [11]. This means that CRISPR/Cas9 genome editing of growth factor-producing plants can reduce the cost of cultured meat production to one-tenth of conventional methods [11].

The Future of Artificially Cultured Meat

While Japan may not experience the same meat-related problems due to its abundance of food, a broader perspective reveals that food problems associated with population growth are much larger and deeper-rooted than previously thought. Numerous researchers and companies are addressing these issues using the latest technologies. As members of the global community, we Japanese need to take an interest in these issues and consider how to solve them.

References

[1] Company opens the first industrial cultured meat facility, with immediate outlook toward U.S. expansion
[2] 世界の人口推計2019年版
[3] What is the true cost of eating meat?
[4] Hannah Ritchie, “Half of the world’s habitable land is used for agriculture “, Our World in Data, Nov. 11, 2019.
[5] Mekonnen, Mesfin & Hoekstra, Arjen. (2010). The green, blue and grey water footprint of farm animals and animal products. American Journal of Hematology – AMER J HEMATOL.
[6] UPSIDE Foods
[7] Method for scalable skeletal muscle lineage specification and cultivation
[8] Methods for extending the replicative capacity of somatic cells during an ex vivo cultivation process
[9] Core Biogenesis
[10] Growth factor research is key to making cell-based meat affordable
[11] Using plants as biofactories to produce high-value molecules 10 times cheaper