開始內容
裝飾
山中伸彌

第191屆 

學位頒授典禮

 (2014)

山中伸彌

名譽科學博士

Mr Pro-Chancellor,

Professor Shinya Yamanaka is one of the world's leading stem cell researchers who, for his highly innovative work, has received a Nobel Prize.

Shinya was born in Osaka where his father owned a small factory. This stimulated an early interest in technical subjects. He was, however, as a schoolboy also a keen judo enthusiast which led to many injuries. Ironically, his frequent hospital visits stimulated an even greater interest in medicine!

He received his MD from Kobe University in 1987 and a doctorate from Osaka City University in 1993. Having spent three years at the Gladstone Institute of Cardiovascular Disease in California, he returned to Osaka City University as assistant professor where one of his main roles was to look after the well-being of mice, a job that left him unfulfilled.

Instead, he was much more passionate about doing his own research. Having secured a post at the Nara Institute of Science and Technology, he began the research which would ultimately bring him great acclaim: pluripotent stem cells and how most effectively and ethically to harvest them.

By the end of the 20th century many countries including Japan had implemented strict measures on the use of human embryos for research due to ethical issues. Shinya believed that he could devise a technique whereby the cells of an adult animal could be reprogrammed to their embryonic state.

Let me explain further. As most of our audience will be fully aware, all life begins when a fertilised egg divides to form new cells, which, in turn, further divide. The cells at the early divisions are embryonic cells: they are identical and pluripotent. This means that they are capable of generating all cell lineages of the body and can develop into all cell types. These embryonic cells, however, become increasingly varied over time and, as a result of this process, become specialised depending upon their location in the body - for example, whether in bone, nerve, blood, muscle or kidney. It had long been thought that these mature or specialised cells could not return to an immature or pluripotent state, but, as early as 1962, Dr John Gurdon had demonstrated, using frogs, that it was possible to use an adult cell to generate a fully functional tadpole by using cloning techniques. The challenge remained, however, as to how an adult cell could most effectively be reprogrammed to become fully pluripotent.

Shinya was determined to overcome this challenge. Staffing his laboratory with exceptionally talented young researchers and working very long hours, Shinya sought to identify the correct gene combination within the genome of mice that would convert adult stem cells back to their original or pluripotent state. The magical moment of truth came in 2006 when the correct gene combination was confirmed. It meant that it was no longer necessary to use living human embryos to provide stem cells - rather an existing adult cell could be reprogrammed by adding a small number of key genes into its primitive or pluripotent stem-cell form. The technique was first derived from using adult mouse fibroblasts, but subsequently proven to be equally applicable to human adult fibroblasts. The resulting cell was named induced pluripotent stem cell, or iPS cell.

As it happened a group of HKU professors were visiting Shinya's laboratory on the day of the publication of his ground-breaking paper identifying the four reprogramming factors. Even amidst the excitement and the demands of the press, Shinya took time to meet our colleagues and tell them about his discovery.

This discovery brought with it far-reaching and exciting results, not just affecting the manner in which stem cell research is conducted, but in studying and treating disease, especially in the developing field of regenerative medicine. The iPS technique means that researchers now have an unlimited source of stem cells. Further, iPS cells can be readily used to learn more about diseases. Many diseases arise when certain types of cells in the body are mal-functioning. But the exact cause is often difficult to study because the cells are found in inaccessible parts of the body, such as the brain or the heart. Using the iPS cell technique, researchers can reproduce symptoms of the disease on iPS cell-derived cells. All that is required is a skin or blood sample from the patient and Shinya's recipe for reprogramming. The cells from the sample are first converted into iPS cells, and then they are induced to differentiate into the type of cell the researchers want to study. These cultured cells have exactly the same genes and mutations as the cells in the patient's body. This makes the method suitable for studying various diseases such as Lou Gehrig's disease and Alzheimer's disease. In the same way, this technique can be used to study what effects various pharmaceuticals have on the diseased cells.

Shinya's remarkable accomplishment was celebrated around the world. In 2007 he was recognised as a "Person who Mattered" in the Person of the Year edition of Time Magazine. He has received an array of awards, including the Shaw Prize in 2008, the Wolf Prize in Medicine in 2011, the Millenium Prize in 2012 and in 2012 Shinya and John Gurdon were awarded the Nobel Prize for Physiology or Medicine "for the discovery that mature cells can be reprogrammed to become pluripotent".

In 2013 he was awarded the Breakthrough Prize in Life Sciences for his work.

Shinya now holds the posts of Director of the Center for iPS Cell Research and Application and Professor at Kyoto University. He also holds the post of Senior Investigator at the Gladstone Institutes in San Francisco.

What drives this remarkable man? Asked this question Shinya has replied:

"My goal as a physician-turned scientist is to help as many patients around the world as possible, and I hope many researchers will use iPS cell technology as a research tool to develop new cures to various intractable diseases".

Shinya is no stranger to Hong Kong and our University. He first visited us in 2004 to speak at the Faculty of Medicine's Frontiers of Biomedical Research conference when he shared his aim and strategy of finding the programming factors for pluripotency. Since then he has visited our University twice, most notably to deliver the Shaw Prize Lecture in 2008.

He left a lasting impression as a humble person who was most generous in sharing his expertise with colleagues.

Shinya does not spend his whole time in the laboratory, however. Always keen on long distance running, Shinya competed in the inaugural Osaka Marathon in 2011 and participated in the Kyoto Marathon in 2012 to raise money for iPS cell research.

In short Shinya's remarkable accomplishments have revolutionised medical research.

Mr Pro-Chancellor, it is my honour and privilege to present to you Professor Shinya Yamanaka for the award of Doctor of Science honoris causa.

Citation written and delivered by Professor Michael Wilkinson, the Public Orator of the University. 

裝飾