Seed Grantee - Isabella De Luca

The Potential of Plant-Derived Compounds in Shaping Muscle Development

By Isabella De Luca

Animal serum, such as fetal bovine serum, is often used in the growth media of cell cultivated meat products and is one of the most costly elements of the manufacturing process, effectively preventing the possibility of reaching price parity with conventional meat products. Our study examined whether adding natural compounds to the cell culture media could be used as part of an alternative to animal sera.

We wanted to understand the effects of plant-derived bioactive compounds (PDBC) on the formation of skeletal muscle, a process called myogenesis; and to determine whether adding natural compounds to the cell culture media could alter muscle cell development. Our target was the growth of myotubes, which are the precursor to mature muscle fibres in the myogenesis process. 

Using an immortalised mouse muscle cell line we added natural compounds with the aim of increasing the rate at which myotubes were formed or  the size of myotubes. If these natural compounds had an impact on the muscle-development process, a follow-up study could examine whether PDBCs could support myogenesis and cell growth without using expensive animal sera in the culture growth media.

Key Insights from the Research

1. PDBCs Alter Myotube Formation: A Reversible Effect
   The exposure of myoblasts to PDBCs during differentiation proved to be a game-changer. Typically, myoblasts fuse to form multinucleated myotubes, a crucial step in the maturation and differentiation process. However, when exposed to PDBCs, this fusion was inhibited. Importantly, the researchers found this effect to be reversible. After 48 hours of exposure to PDBCs, returning the myoblasts to normal differentiation conditions allowed myotubes to develop normally. This suggests a nuanced control over myogenesis and muscle cell growth through the application of PDBCs.
   Figure 1: Key stages of skeletal muscle cell growth and development (myogenesis).
2. PDBCs Induce Breakdown of Existing Myotubes: A Complex Scenario
   The study uncovered that existing myotubes, already in the maturation process, broke down when exposed to PDBCs. Interestingly, different combinations of PDBCs demonstrated varying effects. While PDBC-A alone caused breakdown, combinations like PDBC-A+PDBC-B or PDBC-A+PDBC-C prevented the breakdown, suggesting a delicate interplay between these compounds in preserving myotubes.
   Figure 3: PDBC-A prevents myoblasts from fusing to form myotubes (B). When cells are grown in combination with PDBC-A+PDBC-B or PDBC-A+PDBC-C, myotubes are still able to form normally, suggesting PDBC-B and PDBC-C can inhibit the effects of PDBC-A.

Figure 1: Key stages of skeletal muscle cell growth and development (myogenesis).

Figure 2: Skeletal muscle cells fuse together and form myotubes within two days of growing in standard differentiation media (A). More mature and rounded myotubes are present by four days of differentiation. PDBC-A prevents myoblasts from fusing to form myotubes (B), which is reversible when PDBC-A is replaced by standard differentiation media (C).

Figure 3: Skeletal muscle cells fuse and form myotubes within two days of growth in standard differentiation media (A). Mature, rounded myotubes are present by four days of differentiation. PDBC-A prevents myoblasts fusing to form myotubes (B). When cells are grown in combination with PDBC-A+PDBC-B or PDBC-A+PDBC-C, myotubes are still able to form normally, suggesting PDBC-B and PDBC-C can inhibit the effects of PDBC-A. 

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What does this mean? 

If PDBCs can control specific stages of muscle cell development, then we may be able to reduce the need for animal sera (and other animal-derived products) in some cell culture conditions. We will need to test these PDBCs in a range of conditions where the amount of serum in the cell culture media is reduced to determine whether muscle cells can still mature normally. Considering the effects of some PDBCs on muscle cells are reversible, we could also investigate different combinations of PDBCs to determine effects on the rate of myotube formation and myotube growth.

The findings from this project highlights the potential of manipulating myogenesis to engineer cultured meat and seafood to help meet ever-changing global food/protein demands and benefit human health. Creating an environment where muscle cells can mature faster and more efficiently may have implications for reducing the resources needed to increase the efficiency of cultured meat and seafood production.

The findings also have significant biomedical implications, specifically for developing strategies that enhance muscle cell transplantation relevant to treating muscle injuries and addressing muscle wasting and weakness in ageing and other conditions. The capacity to manipulate myogenesis means the potential to maintain cell development at a premature stage of differentiation, with PDBCs being injected into damaged muscles to assist and promote successful muscle repair.

Although scientists have been studying muscle cell development in culture for decades, it is clear that these techniques are relevant to advancing initiatives for a multitude of food and biomedical industries.

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I would like to thank Dr. Marissa Caldow and Professor Gordon Lynch of the Centre for Muscle Research (CMR) in the Department of Anatomy and Physiology at The University of Melbourne for their support and supervision of this research.