Regeneration of anatomy is foreign to humans, yet common in nature. When a caterpillar metamorphoses into a butterfly, it destroys its neural structure to form a new brain. A flatworm Planaria can be cut to 250 pieces, and every piece will regenerate the necessary body parts to become an independent organism. Its tail will regrow a head, while its head will regrow a tail.
However, studies have shown that regeneration doesn’t simply end with the regrowth of the animal’s anatomy, as each new organ also stores memory. For caterpillars, butterfly with a new brain recognizes the flower it called home as a caterpillar. For flatworms, not only does the tail retain the memory from before it was cut, it can also reprogram its regeneration scheme. If placed in different bioelectric environments, a body part will change its regeneration path and save that information permanently. When the head portion is stimulated with negative charge, it will grow a normal tail. In contrast, positive charge will lead to growth of another head. If this second head is cut, it will still grow a new head without stimulus. These discoveries are a few among many that Dr. Michael Levin explores in his lab.
Broadly, his work answers questions surrounding the regenerative characteristics of multicellular organisms. Specifically, he investigates not only which bioelectrical signals activate the patterning needs of the developing and regenerating cells, but also the mechanism of information processing behind cellular networks. By using novel techniques from molecular genetics, biophysics, and artificial intelligence, he models patterning of cells to clarify the links between genetic networks and bioelectric code on computers. He then verifies these models in a wet lab.
Let’s consider how a lizard regrows its tail. Although cuts that a lizard may suffer will vary, it will maintain its previous form when it regrows its tail. The existing solution of trying to understand the detailed properties of each cell and mathematically modeling them is difficult due to the immense complexity that arises from this plasticity. To answer how a lizard’s tail has such flexibility during regeneration, the interaction of multicellular network of cells that consistently reproduces the same tail should be examined. By viewing each cell as a primitive cognitive and communicative agent that makes autonomous decisions on shapes, Dr. Levin is leading biology down an uncharted path.
Dr. Thomas Skalak, the founding executive director of the Paul Allen Frontiers Group, was one of the first to recognize the value of Dr. Levin’s research. After deciding to inject 10 million dollars into this research, Dr. Skalak remarked that the traditional research spent “past 30 years figuring out all the working parts— what genes express which proteins, how to make modifications of cells, hoping that we would hit upon which molecules are responsible for cancer or diabetes or other major challenges.” He added that: “we’re in a new era now, where computational power is great enough to actually address the massive complexity that’s in bioscience.”
Dr. Levin’s new findings tackle questions unresolvable with past approaches. Prior research in neuroscience discovered that identifying the full neural anatomy of the flatworm C. Elegans did not translate into comprehensive explanation of its functions that induce processes such as regeneration of a lost limb. The implications of his research are immense, including regeneration of diseased organs and control of cancer. Moreover, his research surprisingly shares a common mechanism: interaction between voltage gradients that stores information through complex interactions. Dr. Levin’s research shows that we are on the right path to uncovering communicative paths of cells, which will revolutionize the medical field.