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日本英国科学家分享2012年诺贝尔生理学医学奖,一本书读懂他们的成就《干细胞的希望》

(2012-10-09 07:24:58)
标签:

诺贝尔奖

生理学或医学奖

2012年诺贝尔奖

教育

http://y1.ifengimg.com/tech_spider/dci_2012/10/58f25256f513cd3c1d9ff25e1defd3cd.jpg

The Stem Cell Hope: How Stem Cell Medicine Can Change Our Lives

     (BY Alice Park)
瑞典卡罗琳医学院8日在斯德哥尔摩宣布,将2012年诺贝尔生理学或医学奖授予英国科学家约翰·格登和日本科学家山中伸弥,以表彰他们在细胞研究领域作出的突出贡献。

 
证明细胞发育“可逆”

  诺贝尔奖评选委员会在当天的一份声明中说,很长一段时间里,人们曾认为未成熟细胞发展成特定成熟细胞是单向性的,不可能再回复到多功能干细胞的阶段。

  距今50年,即1962年,格登在英国《胚胎学与实验形态学杂志》发表论文,报告一项发现:细胞的特化机能可以逆转。在诺奖评审委员会称之为“经典”的一项实验中,格登以青蛙的卵细胞为实验对象,取出卵细胞内一个不成熟的细胞核,以一个成熟的特化肠细胞所含细胞核取代,而改性后的卵细胞最终得以发育成为一个正常蝌蚪。他认定,经过改性,细胞成熟后所含脱氧核糖核酸(DNA)遗传物质依然包含发育成为青蛙所有细胞所需要的全部信息。

  这一认定挑战生物学界先前所持有的“信条”,即对应于特定生物机能的特化细胞发育过程不可逆。

  用基因对细胞再编程

  与格登发表论文间隔42年,即2006年,山中伸弥及其同事在《细胞》杂志发表论文,报告一种与格登不同的生物体“介入”方式,那就是,借助基因实现对细胞的“再编程”过程。

  山中伸弥发现完整的特定成熟细胞如何在老鼠体内重组成为非成熟干细胞,通过引入少数基因,他能将特定成熟细胞重新编程为诱导多功能干细胞,这种细胞与其他多功能干细胞的特点一样,都能发育成各种其他器官的细胞。

  颠覆人类对自身发展认识

  诺贝尔奖评选委员会认为,这些突破性的研究完全改变了人类对自身发展和细胞分化的认识,现在人们知道已分化的特定细胞不一定仅局限于其专门的状态。随着教科书的改写,新的相关领域研究也被确立。通过对人体细胞的重新编程,科学家开辟出了疾病研究的新途径,并为疾病治疗找到了新突破口。

  今年的诺贝尔生理学或医学奖奖金共800万瑞典克朗(约合114万美元),由两名获奖者平分。

  徐勇(新华社专稿/专电)

  ■ 反应

  野田打电话贺山中获奖

  山中伸弥成第19位获诺奖日本人

  京都大学教授山中伸弥获2012年诺贝尔生理学或医学奖,成为第19位获得诺贝尔奖的日本人,也是自1987年美国麻省理工学院教授利根川进以来第二位获得诺贝尔医学奖的日本人。

  山中伸弥8日晚在京都大学召开记者会。他表示:“没有国家对我的支持就不会获奖。这是日本整个国家获得的荣誉。”

  山中在记者会上还通过手机与日本首相野田佳彦通话。山中称太紧张不记得野田的所有对话,野田在电话里说:“代表国家,感谢你所获的奖项给日本的民众带来生气。”山中说:“非常感谢。全靠国家对我的支持,今后还将更加努力。”(景青)

  ■ 新闻背景

  医学奖12月10日颁奖

  诺贝尔生理学或医学奖是为了表彰在生理学或者医学领域有重要的发现或发明的人。

  根据阿尔弗雷德·诺贝尔逝世前所立下的遗嘱,诺贝尔生理学或医学奖应由位于瑞典首都斯德哥尔摩的卡罗琳医学院负责颁发。颁奖仪式于每年12月10日,诺贝尔逝世周年纪念日举行。

  原本诺贝尔医学奖的评选由卡罗琳医学院的教员完成。现在的评选工作,根据诺贝尔基金会的相关章程,由卡罗琳医学院的诺贝尔大会负责,此大会是由50名选举出来的卡罗琳医学院名教授组成。(宗和)

  ■ 专家解读

  细胞“返老还童”成医学新突破

  干细胞来源、异体移植排斥反应有望得到解决

  专家认为,约翰·格登和山中伸弥的研究,不仅证实了细胞可以重新编程实现“返老还童”,还为疾病的研究和诊治提供了新的途径。

  科学研究里程碑

  北京大学生命科学学院苏都莫日根教授介绍,心脏、肌肉、肝脏等组织或器官的形成过程中,细胞核已经编辑好了程序,执行不同的功能,走不同的道路。

  苏都莫日根举例说,皮肤的细胞核提供的遗传信息能保证皮肤细胞功能正常。如果大面积失去皮肤,就得把其他组织或器官细胞培育成皮肤细胞,但这些细胞具有其他组织所规定的功能,已经“被程序化”,“这些细胞要培育成皮肤细胞,必须对细胞核去分化和再分化,即朝着皮肤细胞发育的程序,重新编程。”

  果壳网研究员刘旸认为,约翰·格登和山中伸弥的研究都具有里程碑式的意义。约翰·格登证明了成熟细胞最终可以“逆向”,改变了人们的观念。而山中伸弥人工诱导出干细胞,“人们接下来研究不用取真正的干细胞了”,给实验研究提供了很多便利。

  器官移植或有突破

  辽宁大学生命科学院王秋雨教授表示,山中伸弥最大的贡献在于解决了干细胞的来源问题。他介绍,以前的干细胞取自于胚胎,而胚胎的资源很有限,而且必须在短时期内操作,还会涉及法律和伦理问题。细胞重新编程解决了干细胞的来源问题,在器官移植和基因治疗方面贡献很大。

  王秋雨介绍,目前器官移植多是异体移植,往往产生排斥,成功率比较低,还需要供体。用同一体内的细胞培育移植可能会提高成功率。如今这项技术在科学研究领域得到应用,下一步可以尝试应用于医学治疗。


以上中文来自 http://news.qq.com/a/20121009/000088.htm

 

Stem Cell Scientists Awarded Nobel Prize in Physiology and Medicine

In what researchers view as validation of the field, the Nobel committee on Monday recognized pioneering contributions to stem cell science by John Gurdon and Shinya Yamanaka

In a testament to the revolutionary potential of the field of regenerative medicine, in which scientists are able to create and replace any cells that are at fault in disease, the Nobel Prize committee on Monday awarded the 2012 Nobel in Physiology or Medicine to two researchers whose discoveries have made such cellular alchemy possible.

The prize went to John B. Gurdon of the University of Cambridge in England, who was the first to clone an animal, a frog, in 1962, and to Shinya Yamanaka of Kyoto University in Japan who in 2006 discovered the four genes necessary to reprogram an adult cell back to an embryonic state.

Sir John Gurdon, who is now a professor at an institute that bears his name, earned the ridicule of many colleagues back in the 1960s when he set out on a series of experiments to show that the development of cells could be reversed. At the time, biologists knew that all cells in an embryo had the potential to become any cell in the body, but they believed that once a developmental path was set for each cell — toward becoming part of the brain, or a nerve or muscle — it could not be returned to its embryonic state. The thinking was that as a cell developed, it would either shed or silence the genes it no longer used, so that it would be impossible for a cell from an adult animal, for example, to return to its embryonic state and make other cells.

(MORE: Stem Cell Miracle? New Therapies May Cure Chronic Conditions Like Alzheimer’s)

Working with frogs, Gurdon proved his critics wrong, showing that some reprogramming could occur. Gurdon took the DNA from a mature frog’s gut cell and inserted it into an egg cell. The resulting egg, when fertilized, developed into a normal tadpole, a strong indication that the genes of the gut cell were amenable to reprogramming; they had the ability to function as more than just an intestinal cell, and could give rise to any of the cells needed to create an entirely new frog.

Just as Gurdon was facing his critics in England, a young boy was born in Osaka, Japan, who would eventually take Gurdon’s finding to unthinkable extremes. Initially, Shinya Yamanaka would follow his father’s wishes and become an orthopedic surgeon, but he found himself ill-suited to the surgeon’s life. Intrigued more by the behind-the-scenes biological processes that make the body work, he found himself drawn to basic research, and began his career by trying to find a way to lower cholesterol production. That work also wasn’t successful, but it drew him to the challenge of understanding what makes cells divide, proliferate and develop in specific ways.

In 2006, while at Kyoto University, Yamanaka stunned scientists by announcing he had successfully achieved what Gurdon had with the frog cells, but without using eggs at all. Yamanaka mixed four genes in with skin cells from adult mice and turned those cells back to an embryo-like state, essentially erasing their development and turning back their clock. The four genes reactivated other genes that are prolific in the early embryo, and turned off those that directed the cells to behave like skin.

(MORE: Ovary Stem Cells Can Produce New Human Eggs)

By that time, researchers had already shown that cells taken from embryos at their earliest stages could also yield such embryonic stem cells, but Yamanaka rewrote biology by demonstrating that it was possible to turn adult cells into stem cells — cells that are now known as induced pluripotent stem cells, or iPS cells — without the help of either an egg (and whatever factors within eggs that influence early development) or an embryonic cell.

Taken together, Gurdon’s and Yamanaka’s discoveries have turned fundamental biological concepts on their head. Their experiments prove that every cell, whether young or old, in embryos or in adults, has a similar ability to reprogram itself to become “young” again, and thus capable of becoming any cell in the body. What’s more, Yamanaka’s advance provided a practical solution to a thorny issue plaguing researchers interested in pursuing stem cell biology: that the only source of human embryonic stem cells are embryos, which must be destroyed in the process — a problem that was morally sticky enough to compel President George W. Bush to issue in 2001 a ban on the creation of new stem cell lines from excess embryos discarded during fertility treatments (the ban was removed by President Barack Obama in 2009).

(MORE: Early Success in a Human Embryonic Stem Cell Trial to Treat Blindness)

Yamanaka’s method further brings the potential for each patient to become his own resource for replacement cells closer to reality — thus treating disease. Within weeks of Yamanaka’s published report on his discovery in 2006, laboratories around the world had adopted the “Yamanaka factors,” as they are called, to generate abundant lines of stem cells from skin and other mature cells. Within a year, Yamanaka had taken the next important step in his research — applying his achievements with mouse cells to human skin cells and turning them back to an embryo-like state.

“What we have is the discovery of a game-changer in terms of how we approach human disease in the coming years,” Dr. Deepak Srivastava, director of the Roddenberry Center for Stem Cell Biology and Medicine at the Gladstone Institutes, where Yamanaka completed a postdoctoral fellowship and remains a faculty member, said during a press conference celebrating the Nobel announcement on Monday. “In the next five to 10 years we are likely to see the same technology regenerate organs and create new treatments in regenerative medicine for many different human diseases.”

Indeed, just over a year ago, the first groups of human patients received treatment with embryonic stem cells. In a clinical trial designed to test the safety of the treatment, Sue Freeman and Rosemary (who declined to use her real name for reasons of privacy) became the first patients to receive retinal cells that had been grown in the lab from stem cells. Each woman suffered from a different form of macular degeneration, and both were gradually becoming blind. Their doctor, Dr. Steven Schwartz at the University of California, Los Angeles, told them that the cells they received could stop their disease from robbing them completely of their vision. But there was also the chance that the cells would do nothing at all, and possibly even cause them harm, by forming tumors or other abnormal growths in the eye — a gamble that had to be anticipated, given that the treatment was unproven and never before tested in humans.

(MORE: A Stem Cell First: Using the ‘Dolly’ Method on Human Cells)

While Freeman and Rosemary are among the pioneers of human embryonic stem cell research (a previous human trial also using cells made from embryonic stem cells, to treat spinal cord injury, was halted by the company sponsoring the studies for financial reasons), it won’t be long before embryos may not be needed at all. Using Yamanaka’s method, labs around the world have generated lines of heart, brain, nerve and muscle cells made from iPS cells from patients with diseases ranging from Alzheimer’s to spinal cord injury and diabetes, all in the hope of understanding where in development these cells go awry and how to develop new treatments that address these aberrations.

Already, Yamanaka says that researchers at the Center for iPS Cell Research at Kyoto University, which he heads, are preparing to transplant retinal cells made from iPS cells into patients with macular degeneration next year. “The biggest hurdle is safety,” he told reporters during a teleconference about moving iPS cells into the clinic. “Especially in regenerative medicine, you have to double check that you won’t see any severe side effects in patients. We need to confirm the technology is safe.”

The concern is that because iPS cells are made from already mature cells that have been manipulated to become other types of cells, they may interact with chemicals and other tissues once in the body to form abnormal growths, or they may fail to develop into the cells required to treat a disease. Studies by stem cell scientists show that while iPS cells are, for the most part, nearly indistinguishable from embryonic stem cells, they do show some differences that aren’t fully understood yet.

(MORE: Stem Cell Research: The Quest Resumes)

Still, the technology, as the Nobel Prize committee acknowledged, represents a breakthrough in our understanding of cellular development, and could provide the key to finally curing disease such as diabetes or Alzheimer’s, in which patients suffer from diseased or failing cells that could one day be replaced by healthy ones they grow themselves.

“It’s spectacular that the Nobel committee recognizes the contribution of these scientists,” says Schwartz. “I think it helps the public get enthusiastic about regenerative medicine and to catch up with the science.”

MORE: Stem Cells That Kill

MORE: Banking on Stem Cells

Alice Park is a writer at TIME and the author of The Stem Cell Hope, which details the contributions of leading stem cell scientists, including Gurdon and Yamanaka, to the emerging field of regenerative medicine. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.


Read more: http://healthland.time.com/2012/10/08/stem-cell-scientists-awarded-nobel-prize-in-physiology-and-medicine/#ixzz28l1iFagk

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