Protein Key to Control Growth of Blood Cells
PHILADELPHIA, August 05, 2008 /PRNewswire-
sheds light on the biological events by which stem cells in the bone
marrow develop into the broad variety of cells that circulate in the
blood. The findings may help improve the success of bone marrow
transplants and develop better treatments for life-threatening blood
diseases.
"As we better understand the biological pathways that regulate the
growth of stem cells, we may identify new approaches for treating
blood disorders," said study leader Wei Tong, Ph.D., a hematology
researcher at The Children's Hospital of Philadelphia. Her study
appeared online July 10 in the .
Hematopoietic stem cells (HSCs) develop into all types of blood
cells: red blood cells, white blood cells, platelets, and immune
cells. HSCs, like other stem cells, have the ability to self-renew:
each can give rise to more mature, developed cells with more specific
functions, as well as a new stem cell. (Everyone carries HSCs in
their bone marrow, unlike embryonic stem cells, which exist only in
embryos.)
In her study, conducted in mice, Tong focused on a protein called Lnk
that helps control HSC expansion. When a growth factor in the blood
called thrombopoietin (TPO) acts on its cell receptor, it triggers
signals along a pathway that includes another protein, JAK2. JAK2, in
turn, causes stem cells to increase their numbers.
Tong's group and others previously found that Lnk is a negative
regulator for HSCs, acting as a brake on stem cell expansion. In the
current study, they found that mice genetically engineered to lack
the Lnk protein had 10 times the normal amount of HSCs in their bone
marrow. Without Lnk to directly interact with JAK2 and inhibit its
activity, TPO made stem cell production go into overdrive.
However, there was an unexpected potential benefit -- the expanded
population of stem cells had a higher proportion of quiescent cells,
those in a resting stage in the cell cycle. Quiescent stem cells,
said Tong, are more likely to succeed in a recipient when they are
used in bone marrow transplantation.
Although much research remains to be done, added Tong, other
researchers might build on this knowledge to manipulate HSCs for more
effective bone marrow transplants for cancer patients after high dose
chemotherapy or radiotherapy and treatments for particular blood
disorders. Aplastic anemia, severe combined immunodeficiency and
hemoglobin disorders, for example, involve deficiencies of specific
immune cells in the blood. Using a drug to inhibit Lnk could
potentially produce larger numbers of HSCs for a successful bone
marrow transplant.
Myeloproliferative disorders (MPDs), on the other hand, entail the
opposite danger -- a sometimes-fatal overproduction of certain bone
marrow cells. Clinicians might use Tong's research on Lnk and its
associated signaling pathway to curtail stem cell production and
control MPDs.
The National Cancer Institute, part of the National Institutes of
Health, supported Tong's research, with additional grant funding from
the McCabe Foundation and CHOP Institutional Development Fund. Tong's
co-authors were Alexey Bersenev, Chao Wu, and Joanna Balcerek, all of
the Division of Hematology at The Children's Hospital of Philadelphia.
The Children's Hospital of Philadelphia was founded in 1855 as the
nation's first pediatric hospital. Through its long-standing
commitment to providing exceptional patient care, training new
generations of pediatric healthcare professionals and pioneering
major research initiatives, Children's Hospital has fostered many
discoveries that have benefited children worldwide. Its pediatric
research program is among the largest in the country, ranking third
in National Institutes of Health funding. In addition, its unique
family-centered care and public service programs have brought the 430-
bed hospital recognition as a leading advocate for children and
adolescents. For more information, visit http://www.chop.
Contact: Ashley Moore
The Children's Hospital of Philadelphia
Phone: (267) 426-6071
CONTACT: Ashley Moore of The Children's Hospital of Philadelphia,
267-426-6071, mooreA1@email.
Web site: http://www.chop.
http://www.pharmali
articleid=560851&
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
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
____________________________________________
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___
No comments:
Post a Comment