Professor Dr Elly Margaret Tanaka

Research Priorities: Regeneration of complex body structures, molecular and cellular foundations, molecular genetics, axolotl, organoids
Elly Tanaka is an American biochemist. She studies the regeneration of complex body structures, such as the nervous system and limbs of four-legged animals, as well as their molecular and cellular foundations. Her main model organism is the regenerative salamander Ambystoma mexicanum, commonly known as the axolotl. She has honed this animal’s molecular genetics and also uses organoids in her research. The key question of her research projects seek to answer is why some species are able to regenerate while others cannot. 
Elly Tanaka studies the regeneration of complex body structures, with a particular focus on the salamander, which is able to regenerate its limbs and spinal cord. Elly Tanaka managed to identify the stem cells responsible for this complex regeneration in the axolotl, as well as the signals that trigger cell growth after an injury. Using molecular genetics she managed to show, that the regeneration of limbs is based on the development of stem cells from various tissue layers, including skin, muscles, and nerves, from which the complex tissue structure of functional limbs regenerates. She also analyses neural stem cells that are involved in regenerating the spinal cord and brain. Elly Tanaka discovered that adult type neural stem cells dedifferentiate to an embryonic type neural stem cell in order to grow the new spinal cord.
Tissue cells react to amputation with a series of molecular factors from the blood and the injured epidermis, which initiates the process of cell migration and cell proliferation. In order to regenerate complex body parts such as tails and other extremities, both tissue growth and coordination of the various tissues and the entire structure are required. Elly Tanaka showed that a subpopulation of the skin, the dermis, organises the regeneration of all other tissues. These cells carry the information as to whether the regeneration concerns the cells of the upper tail or the hand. 
Elly Tanaka’s research group also investigates why the regeneration process ceases to work in frogs after metamorphosis, and why in mice it only occurs in the tips of fingers and toes. They study related stem cell populations to find out whether the potential and development of stem cells between the two species is different. In particular, they investigate how differently the stem cells react to regeneration-specific signals.
On the one hand, these studies serve as the starting point for an investigation of the question of how mammals such as mice have lost the ability to regenerate during their evolutionary process. For this purpose, the working group created a three-dimensional spinal cord tissue from the embryonic stem cells of mice. On the other hand, their work aims to advance the development of new strategies to regenerate or replace mammalian tissues. To this end, they have directed human embryonic stem cells to form retinal tissues including the pigmented retinal epithelium (RPE). In turn, these cells are used to screen for potential drugs that could ameliorate defects in RPE cells that are known to cause progressive blindness.