YOKOHAMA CITY UNIVERSITY

Third day of the Science Summer Program

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Lecture 6 Analyses of genes controlling regeneration and organ creation

Prof. Hideho Uchiyama, Ph.D., Department of Regenerative and Developmental Biology, Graduate School of NanoBio Sciences

The lectures of the third day were delivered at the Advanced Research Laboratory of the University of Tokyo Komaba Campus.

Prof. Uchiyama gave a lecture titled ‘From Drs. Spemann to Yamanaka,’ in which he presented a general outline of regenerative and developmental biology.

Following an introduction of familiar topics concerning biotechnology from experiments conducted by Dr. Spemann to the creation of clone animals and mechanisms through which an individual develops from a fertilized egg were explained. Prof. Uchiyama also talked about ES cells and iPS cells that are currently being actively scrutinized.

Ordinarily, the type of tissues into which the cells of a developed individual differentiate and grow is determined beforehand. Therefore, it is impossible to create the tissues of the heart by culturing the cells that have differentiated to compose the tissues of the skin.

The ES cells investigated for practical use in regeneration medicine are totipotent, so they are able to differentiate to compose the cells of the tissues of every part of the body. However, because they are created from the cells of a fertilized egg, there are ethical problems to be solved before they become applicable in clinical medicine. Created under these circumstances were iPS cells that have regained the totipotency to differentiate and grow into the cells of every tissue of the body.

iPS cells are able to be created from the cells of a person’s own body, so there are no ethical problems to be cleared. However, a lot of problems still remain to be solved at this stage because the success rate of creating iPS cells is still low. It is expected that, by overcoming such a challenge, they will become applicable for the treatment of diseases that are incurable today.
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In collaboration with Prof.Emeritus Makoto Asashiima, Prof. Uchiyama is conducting research on cytodifferentiation using the pluripotent cells of mammals,

Lecture 7 The future envisaged by research in organogenesis technology and its challenge

Makoto Asashiima, Prof.Emeritus of the University of Tokyo

Following Prof. Uchiyama’s lecture, Emeritus Prof. Asashima delivered a lecture concerning organogenesis outside the body using undifferentiated cells.

The experiment conducted by Prof. Asashima on the induction of organogenesis with animal caps and activins was such a great discovery that it was included in reference books of biology for high school students. He also talked about the process of the experiment.

A cry of amazement occurred from the students when they actually saw pictures on the screen in which the cells that had grown into the heart through induction from the animal caps were transplanted to a frog, the heart of which kept on beating.

The students expressed a deep interest in the actively investigated topics concerning the development of living things in outer space.

Special lecture Practice in organogenesis

Associate Prof. Ariizumi Takafumi, the University of Tokyo Advanced Research Laboratory

The practice took place in the afternoon at a laboratory of the University of Tokyo’s 16th Building.

Cuting off 'animal caps'

In the first training session, ‘animal caps’ used for the experiment by Emeritus Prof. Asashima were actually cut off.

The animal caps refer to a portion of the animal polar. When they are immersed and cultivated in activin, they differentiate to grow into versatile organs according to the concentrations of activin.

The picture on the right shows how the fertilized eggs of the new born platanna are cut off with care while being watched through a microscope. (The fertilized eggs of the platanna used for the practice are shown.)

The fertilized eggs were as large as 3mm. However, all the students present found difficulty freely moving the eggs with tweezers while watching through a microscope. They peered through microscopes with the aid of the 3 lecturers who helped with the experiment.

According to the lecturers, because a large volume of animal caps are required to conduct an experiment on organogenesis with animal caps, the removal of animal caps is an important procedure.

Observing ES cells and iPS cells

Subsequently, the students observed mouse ES cells and human iPS cells.

According to the students who observed them, ES cells are round and congregate, while the human iPS cells are flat and are characterized by their sticking to feeder cells required for culturing.

Those participating took turns looking through microscopes while asking questions from time to time.

mouse ES cells(left) and human iPS cells(right)