Human ES Cells Progress Slowly In Myelin's Direction

[Guest guest]

Human ES Cells Progress Slowly In Myelin's Direction

13 Apr 2009

Scientists from the University of Wisconsin, USA, report in the journal

Development the successful generation from human embryonic stem cells of a type

of cell that can make myelin, a finding that opens up new possibilities for both

basic and clinical research.

The cells the researchers made are called oligodendrocytes, which are

responsible for making myelin in the central nervous system. Myelin forms an

insulating sheath that surrounds nerve fibres, both protecting them and speeding

up the transmission of nerve impulses. Its loss or damage has serious

consequences, as is seen in the condition of multiple sclerosis, because without

it nerves lose the ability to transmit impulses to each other and to function

properly.

Unlike human embryonic stem (ES) cells, it's relatively easy to persuade mouse

ES cells to turn into oligodendrocytes; it's often done by exposing these cells

to a protein called Sonic Hedgehog, which produces oligodendrocytes in the

spinal cord of developing embryos. Now Su-Chun Zhang and his co-workers show in

the May issue of Development (dev.biologists.org) that treating human ES cells

with this same protein also turns them into oligodendrocytes - they just take

longer to do it, 14 weeks as opposed to the 2 weeks taken by mouse ES cells.

They also report another difference between mouse and human ES cells: a growth

factor called Fgf2 that promotes oligodendrocyte development in mouse ES cells

actually stalls it in human ES cells.

As Dr Zhang reveals, these findings were quite unexpected. 'This was quite a

surprise given that this is exactly how we direct mouse ES cells to become

oligodendrocytes. But we have discovered an unexpected twist in the cell's

response to the same external factor', explained Dr Zhang. 'It nevertheless

explains why so many research groups have failed to persuade human neural stem

cells to become oligodendrocytes for the past decade.'

As Dr Zhang went on to discuss, these findings are also of clinical importance.

'We are now able to generate a relatively enriched population of oligodendrocyte

precursor cells that may be used to repair lost myelin sheaths. These findings

also raise awareness of the direct translatability of animal studies to human

biology. In this regard, the human oligodendrocytes generated from human ES

cells or the generation of disease-induced pluripotent stem cells can provide a

useful tool in the future for screening pharmaceuticals directly on human

cells.'

Notes:

Further information

This article appears in the May 1st 2009 issue of Development, which was

published online on April 10th 2009.

Development) is a leading journal in the field of development biology and is

published by the not-for-profit publisher, the Company of Biologists.

The authors are from the Departments of Anatomy and Neurology at the School of

Medicine and Public Health, Waisman Center, University of Wisconsin-Madison,

USA. They are funded by the National Institute of Neurological Disorders and

Stroke and The National Multiple Sclerosis Society.

Source:

Jane Alfred

The Company of Biologists

--------------------------------------------------------------------------------

Article URL: http://www.medicalnewstoday.com/articles/145751.php

[Guest guest]

One big step forward.

>

> Human ES Cells Progress Slowly In Myelin's Direction

> 13 Apr 2009

>

> Scientists from the University of Wisconsin, USA, report in the journal

Development the successful generation from human embryonic stem cells of a type

of cell that can make myelin, a finding that opens up new possibilities for both

basic and clinical research.

>

> The cells the researchers made are called oligodendrocytes, which are

responsible for making myelin in the central nervous system. Myelin forms an

insulating sheath that surrounds nerve fibres, both protecting them and speeding

up the transmission of nerve impulses. Its loss or damage has serious

consequences, as is seen in the condition of multiple sclerosis, because without

it nerves lose the ability to transmit impulses to each other and to function

properly.

>

> Unlike human embryonic stem (ES) cells, it's relatively easy to persuade mouse

ES cells to turn into oligodendrocytes; it's often done by exposing these cells

to a protein called Sonic Hedgehog, which produces oligodendrocytes in the

spinal cord of developing embryos. Now Su-Chun Zhang and his co-workers show in

the May issue of Development (dev.biologists.org) that treating human ES cells

with this same protein also turns them into oligodendrocytes - they just take

longer to do it, 14 weeks as opposed to the 2 weeks taken by mouse ES cells.

They also report another difference between mouse and human ES cells: a growth

factor called Fgf2 that promotes oligodendrocyte development in mouse ES cells

actually stalls it in human ES cells.

>

> As Dr Zhang reveals, these findings were quite unexpected. 'This was quite a

surprise given that this is exactly how we direct mouse ES cells to become

oligodendrocytes. But we have discovered an unexpected twist in the cell's

response to the same external factor', explained Dr Zhang. 'It nevertheless

explains why so many research groups have failed to persuade human neural stem

cells to become oligodendrocytes for the past decade.'

>

> As Dr Zhang went on to discuss, these findings are also of clinical

importance. 'We are now able to generate a relatively enriched population of

oligodendrocyte precursor cells that may be used to repair lost myelin sheaths.

These findings also raise awareness of the direct translatability of animal

studies to human biology. In this regard, the human oligodendrocytes generated

from human ES cells or the generation of disease-induced pluripotent stem cells

can provide a useful tool in the future for screening pharmaceuticals directly

on human cells.'

>

> Notes:

>

> Further information

>

> This article appears in the May 1st 2009 issue of Development, which was

published online on April 10th 2009.

>

> Development) is a leading journal in the field of development biology and is

published by the not-for-profit publisher, the Company of Biologists.

>

> The authors are from the Departments of Anatomy and Neurology at the School of

Medicine and Public Health, Waisman Center, University of Wisconsin-Madison,

USA. They are funded by the National Institute of Neurological Disorders and

Stroke and The National Multiple Sclerosis Society.

>

> Source:

> Jane Alfred

> The Company of Biologists

>

--------------------------------------------------------------------------------

>

> Article URL: http://www.medicalnewstoday.com/articles/145751.php

>