Blood Stem Cell and Neuron Fusion Occurs More Frequently in Chronic
Inflammation
April 21,2008
Researchers discovered that chronic inflammation triggers
hematopoietic stem cells to travel to the brain and fuse with
Purkinje neurons up to 100 times more frequently than previously
believed. After the fusion, the blood-cell nuclei (heterokaryons)
begin to express previously silent, neuron-specific genes, which may
possibly play a role in protecting neurons against damage.
The researchers used lethal doses of radiation to abolish a mouse's
hematopoietic system to transplant a single hematopoietic stem cell
and prove that the fusion cells in the brain were derived from blood.
To see if this fusion would occur even under less physiologically
traumatic conditions, they used a technique called parabiosis, which
surgically joins two mice in such a way that they share a circulatory
system, to introduce blood cells into an unmodified animal.
The researchers found evidence of fusion between blood cells and
Purkinje neurons in this radiation-free system 20 to 26 weeks after
surgery. As in previous experiments, most mice had very low numbers
of fused cells in their cerebellums, but a few had up to 100 times
more. The scientists found that those animals with higher-than-
expected numbers of fused cells also had an inflammatory skin
condition common to aging laboratory mice called idiopathic
ulcerative dermatitis.
The researchers confirmed that the increased number of fused cells
was related to inflammation by using the traditional radiation/bone-
marrow transplant approach in mice with dermatitis and in a mouse
model of multiple sclerosis.
Finally in a cross-species experiment the investigators showed that
nuclei from rat blood stem cells that had fused to Purkinje cells in
mice stopped expressing blood cell proteins and began to express rat
neuron-specific gene products.
This switch exemplifies a type of genetic reprogramming that has been
a source of ongoing debate and great interest in the world of stem
cell research, according to the investigators. Such reprogramming is
critical to the regeneration of functional tissues by stem cells.
The research was a collaborative effort between Stanford University
School of Medicine and the University of British Columbia. The study
was published on April 20 in Nature Cell Biology.
http://www.genengne
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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