Monday, 18 August 2014

Stem Cells Show How Illness-Linked Genetic Variation Affects Neurons

In this image, cell nuclei are shown in
blue and synapses in red and green.
Credit: Zhexing Wen/Johns Hopkins Medicine
A genetic variation linked to schizophrenia, bipolar disorder and severe depression wreaks havoc on connections among neurons in the developing brain, a team of researchers reports.

The study, led by Guo-li Ming, M.D., Ph.D., and Hongjun Song, Ph.D., of the Johns Hopkins University School of Medicine and described online Aug. 17 in the journal Nature, used stem cells generated from people with and without mental illness to observe the effects of a rare and pernicious genetic variation on young brain cells.

 The results add to evidence that several major mental illnesses have common roots in faulty "wiring" during early brain development.

"This was the next best thing to going back in time to see what happened while a person was in the womb to later cause mental illness. We found the most convincing evidence yet that the answer lies in the synapses that connect brain cells to one another." said Ming.

Friday, 15 August 2014

Researchers Trace the Beginnings of Hematopoietic Stem Cells

Red blood cell (left), a platelet (middle)  and a white blood cell.
Blood cells
Red blood cell (left), a platelet (middle)
and a white blood cell.
Hematopoietic stem cells (HSCs) differentiate to all other blood cell types, but there are still many questions about their development and how their fate is decided.

Now, in a new paper published online this week in Nature, researchers from the University of California, San Diego School of Medicine elaborate upon a crucial signaling pathway and the role of key proteins, which may help clear the way to generate HSCs from human pluripotent precursors, similar to advances with other kinds of tissue stem cells.

Principal investigator David Traver, PhD, professor in the Department of Cellular and Molecular Medicine, and colleagues focused on the Notch signaling pathway, a system found in all animals and known to be critical to the generation of HSCs in vertebrates.

Thursday, 14 August 2014

Australian Researchers Unravel the Mystery of Hematopoietic Stem Cell Generation

Professor Peter Currie stem cells
Professor Peter Currie
Credit
A cure for a range of blood disorders and immune diseases is in sight, according to a team of scientists who have unravelled the mystery of hematopoietic stem cell generation. The new study, led by researchers at the Australian Regenerative Medicine Institute (ARMI) at Monash University and the Garvan Institute of Medical Research, appeared yesterday in Nature. It identifies for the first time mechanisms in the body that trigger hematopoietic stem cell production.

Found in the bone marrow and in umbilical cord blood, hematopoietic stem cells (HSCs) are critically important because they can replenish the body's supply of blood cells. Leukemia patients have been successfully treated using HSC transplants, but medical experts believe blood stem cells have the potential to be used more widely.

Lead researcher Professor Peter Currie, from ARMI explained that understanding how HSCs self-renew to replenish blood cells is a "Holy Grail" of stem cell biology.

Tuesday, 12 August 2014

Epigenetics Has Large Say in the Fate of Blood Stem Cells

Epigenetics: Environmental effects influence
 how genes are turned on or off.
Credit: Image courtesy of Weizmann Institute of Science
Every day trillions of blood cells are being formed in our body: from the oxygen-carrying red blood cells to the many types of white blood cells that fight pathogens and infection. All of these highly specialized cells originate from hematopoietic (blood) stem cells -- unique cells that have the potential to mature into all blood types. How exactly is the fate of these stem cells regulated?

Preliminary findings from research conducted by scientists from the Weizmann Institute and the Hebrew University are starting to reshape the conventional understanding of the way stem cell fate decisions are controlled, thanks to a new technique for epigenetic analysis they have developed.

How Breast Cancer Uses the Power of Mammary Stem Cells

Dr. David Cheresh
During pregnancy, certain hormones trigger specialized mammary stem cells to create milk-producing cells essential to lactation. Researchers at the University of California, San Diego School of Medicine and Moores Cancer Center have found that mammary stem cells associated with the pregnant mammary gland are related to stem cells found in breast cancer.

Writing in the August 11, 2014 issue of Developmental Cell, David A. Cheresh, PhD, Distinguished Professor of Pathology and vice-chair for research and development, Jay Desgrosellier, PhD, assistant professor of pathology and colleagues specifically identified a key molecular pathway associated with aggressive breast cancers that is also required for mammary stem cells to promote lactation development during pregnancy.

"By understanding a fundamental mechanism of mammary gland development during pregnancy, we have gained a rare insight into how aggressive breast cancer might be treated. This pathway can be exploited. Certain drugs are known to disrupt this pathway and may interfere with the process of breast cancer progression." said Cheresh.

Friday, 8 August 2014

Dramatic Growth of Grafted Induced Pluripotent Stem Cells in Rat Spinal Cord Injuries

Building upon previous research, researchers at the University of California, San Diego School of Medicine and Veteran's Affairs San Diego Healthcare System report that neurons derived from human induced pluripotent stem cells (iPSCs) and grafted into rats after a spinal cord injury produced cells with tens of thousands of axons extending virtually the entire length of the animals' central nervous system.

Leading author Paul Lu, PhD, of the UC San Diego Department of Neurosciences said the human iPSCs-derived axons extended through the white matter of the injury sites, frequently penetrating adjacent gray matter to form synapses with rat neurons. Similarly, rat motor axons pierced the human iPSCs grafts to form their own synapses.

The iPSCs used were developed from a healthy 86-year-old human male.
"These findings indicate that intrinsic neuronal mechanisms readily overcome the barriers created by a spinal cord injury to extend many axons over very long distances, and that these capabilities persist even in neurons reprogrammed from very aged human cells." said senior author Mark Tuszynski, MD, PhD, professor of Neurosciences and director of the UC San Diego Center for Neural Repair.

Researchers Uncover Stem Cell Behaviour of Human Bowel

For the first time, researchers say they have uncovered new information on how stem cells in the human bowel behave, revealing vital clues about the earliest stages in bowel cancer development and how we may begin to prevent it.

The research, led by Queen May University of London (QMUL) and published yesterday the journal Cell Reports, discovered how many stem cells exist within the human bowel and how they behave and evolve over time.

Thursday, 7 August 2014

Researchers Grow Human Gastrointestinal Cells Using Epithelial Stem Cells

Kelli L. VanDussen and Matthew A. Ciorba stem cell researchers
Kelli L. VanDussen, PhD, and Matthew A. Ciorba
A method of growing human cells from tissue removed from a patient's gastrointestinal (GI) tract may one day help scientists develop tailor-made therapies for inflammatory bowel disease and other GI-related conditions.

Reporting online recently in the journal Gut, researchers from the Washington University School of Medicine in St. Louis said they have made cell lines from individual patients in as little as two weeks.

They have created more than 65 such cell lines using tissue from 47 patients who had routine endoscopic screening procedures, such as colonoscopies. A cell line is a population of cells in culture with the same genetic makeup.

The researchers said the cell lines can help them understand the underlying problems in the GI tracts of individual patients and be used to test new treatments.

Harvard Researchers Identify New Potential Treatment for Amyotrophic Lateral Sclerosis

Sophie De Boer  and Prof. Kevin Eggan stem cell researchers
This image depicts graduate student Sophie De Boer, (left),
and Prof. Kevin Eggan (right)
discussing their latest work.
Credit: B. D. Colen/Harvard University
About eight years ago, researchers at the Harvard Stem Cell Institute (HSCI) begun a series of studies that led to a report published today which may be a major step forward in thequest to developing real treatments for amyotrophic lateral sclerosis (ALS).

The findings by Harvard professor of Stem Cell and Regenerative Biology (HSCRB) Kevin Eggan and his team have also produced functionally identical results in human motor neurons in a laboratory dish and in a mouse model of the disease, demonstrating that the modeling of human disease with customized stem cells in the laboratory could someday relatively soon eliminate some of the need for animal testing.

The new study, appearing in Science Translational Medicine, suggests that compounds already in clinical trials for other purposes may be promising candidate therapeutics for ALS.

Wednesday, 6 August 2014

Cytori Halts Stem Cell Trials Due to Adverse Effects

Cytori (stem cells) logo
Cytori Therapeutics announced yesterday that it has halted trials of its experimental stem cell therapy for heart failure after three patients developed blood flow problems. The San Diego-based company said it placed the hold on two studies after the patients developed problems with blood flow to the brain. Two of the patients' symptoms resolved in a short period of time and a third was still recovering, the company said in a statement.

Cytori said it is working with the Food and Drug Administration and the study's safety monitoring board to understand how the problems occurred. The study hold means the company will not complete enrollment of its lead study for the treatment by the end of 2014, as previously stated.

Researchers Correct Beta-Thalassemia Mutations Using Induced Pluripotent Stem Cells

beta-thalassemia corrected blood cells from iPSCs
This image depicts blood cells with corrected HBB mutations
derived from induced pluripotent stem cells.
Credit: courtesy of Fei Xie, University of California,
San Francisco.
A major hurdle in gene therapy is the efficient integration of a corrected gene into a patient's genome without mutating off-target sites. In a new study published by Genome Research, researchers have used CRISPR/Cas genome editing technology to seamlessly and efficiently correct disease-causing mutations in cells from patients with β-thalassemia.

β-thalassemia results from inherited DNA mutations in the hemoglobin beta (HBB) gene, resulting in reduced HBB expression in red blood cells and, in the most severe forms, anemia.

The only established curative treatment is hematopoietic stem cell transplantation; however, this treatment requires a matched donor. Gene therapy, which delivers a corrected copy of a gene into patient cells, could bypass the need for a donor.

Previous attempts using a virus to randomly insert a normal gene into the genome has been successful in one β-thalassemia patient, but the long-term effect of viral insertion is not yet known.

Molecular Competition Drives Adult Stem Cells to Specialize

All adult organisms ranging from fruit flies to humans harbor adult stem cells, some of which renew themselves through cell division while others differentiate into the specialized cells needed to replace worn-out or damaged organs and tissues.

Understanding the molecular mechanisms that control the balance between self-renewal and differentiation in adult stem cells is an important foundation for developing therapies to regenerate diseased, injured or aged tissue.

Now, in the latest issue of the journal Nature, researchers at the Stowers Institute for Medical Research report that competition between two proteins, Bam and COP9, balances the self-renewal and differentiation functions of ovarian germline stem cells (GSCs) in fruit flies (Drosophila melanogaster).

Tuesday, 5 August 2014

ISCO Launches Stroke Program With Tulane University

International Stem Cell Corporation (ISCO), a California-based biotechnology company developing stem cell based therapies, announced today that it has launched a new Stroke Program. Together with Tulane University, ISCO will study the impact of human parthenogenetic neural stem cells (hpNSC) transplantation in a pre-clinical rodent model of ischemic stroke as a first step toward the clinical development of a potential stroke treatment. The proof-of-concept study will be done in the laboratory of Dr. Jean-Pyo Lee, a well-known expert in the field of regenerative medicine.