Scientists eliminate viral vector in stem cell reprogramming

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Human induced plurtipotent stem cells reprogrammed into germ cell precursors

For the first time, UCLA researchers have reprogrammed human induced pluripotent stem (iPS) cells into the cells that eventually become eggs and sperm, possibly opening the door for new treatments for infertility using patient-specific cells. The iPS cells were coaxed into forming germ line precursor cells which include genetic material that may be passed on to a child. The study appears today in the early online edition of the peer-reviewed journal Stem Cells. “This finding could be important for people who are rendered infertile through disease or injury. We may, one day, be able to replace the germ cells that are lost,” said Amander Clark, a Broad Stem Cell Research Center scientist and senior author of the study. [lien] [EN]

UC Irvine scientists find new way to sort stem cells

UC Irvine scientists have found a new way to sort stem cells that should be quicker, easier and more cost-effective than current methods. The technique could in the future expedite therapies for people with conditions ranging from brain and spinal cord damage to Alzheimer's and Parkinson's diseases. The method uses electrodes on a tiny, inch-long glass slide to sort cells by their electric charges and has been used in cancer research. The stem cell field suffers from a lack of tools for identifying and sorting cells. This important discovery could add a new tool to current sorting methods, which generally require expensive, bulky equipment. “For therapeutic purposes, we want stem cells to turn into specific cell types once they have been transplanted. [lien] [EN]

Scientists Discover Key to Growing New Stem Cells

Scientists at Duke University Medical Center have demonstrated they can grow human stem cells in the laboratory by blocking an enzyme that naturally triggers stem cells to mature and differentiate into specialized cells. The discovery may enable scientists to rapidly grow stem cells and transplant them into patients with blood disorders, immune defects and select genetic diseases, said the Duke researchers. Stem cells are the most flexible cells in the body, continually dividing into new stem cells or into specialized cells that carry out specific roles in the body. But little is known about how stem cells choose their fate. The Duke team focused on “hematopoietic” or blood stem cells. [lien] [EN]

Scientists find previously unknown receptors on adult stem cells

For many years, researchers believed that stem cells in the bone marrow spent most of their existence in a slumber-like state, unaware of — and unaffected by — the daily battles fought by the body's immune system. Not so. Scientists at the Oklahoma Medical Research Foundation have discovered that marrow stem cells — undifferentiated cells that eventually give rise to the blood cells that fight infection — possess receptors that recognize bacteria and viruses. When activated, these receptors kick the stem cells and immature blood cells into action, enlisting them to help fight whatever pathogen is attacking the body. The findings, which appear in the June issue of the journal Immunity, could have important implications for treating leukemias and autoimmune diseases such as lupus and rheumatoid arthritis. [lien] [EN]

In a major breakthrough scientists reprogram human adult cells into embryonic stem cells

Acclaimed stem cell researcher Shinya Yamanaka, MD, PhD, has reported that he and his Kyoto University colleagues have successfully reprogrammed human adult cells to function like pluripotent embryonic stem (ES) cells. Because it circumvents much of the controversy and restrictions regarding generation of ES cells from human embryos, this breakthrough, reported in the journal Cell, should accelerate the pace of stem cell research. Last year, Yamanaka, who is also a senior investigator at the Gladstone Institute of Cardiovascular Disease (GICD), reported that he and his Kyoto colleagues had reprogrammed mouse skin cells into pluripotent stem cells, laying the foundation to apply this methodology in human cells. [lien] [EN]

Breakthrough produces Parkinson’s patient-specific stem cells free of harmful reprogramming genes

Deploying a method that removes potentially cancer-causing genes, Whitehead Institute researchers have “reprogrammed” human skin cells from Parkinson’s disease patients into an embryonic-stem-cell-like state. Whitehead scientists then used these so-called induced pluripotent stem (iPS) cells to create dopamine-producing neurons, the cell type that degenerates in Parkinson’s disease patients. This marks first time researchers have generated human iPS cells, successfully removed the potentially problematic reprogramming genes, and seen the cells maintain their embryonic stem-cell-like state. Previous methods to reprogram mature cells into iPS cells inserted cancer-causing genes into the cells’ DNA. [lien] [EN]

In a major breakthrough scientists find new way to create stem cells without embryos

Stem cells with the capacity to form any type of tissue can be created from adult cells without destroying embryos, according to new research that suggests a way of sidestepping ethical controversy over the field. Three separate teams of scientists have used genetic trickery to wind back the biological clock of mature skin cells from mice, to give them the unlimited potential of stem cells that are normally found only in embryos. Though it remains uncertain whether the same technique would work in humans, the successes raise the prospect that powerful master cells for use in medicine and research could one day be created from adult bodies, removing any need to use embryos. Read the article at Times Online site [lien] [EN]

Scientists unlock mystery of embryonic stem cell signaling pathway

A newly discovered small molecule called IQ-1 plays a key role in preventing embryonic stem cells from differentiating into one or more specific cell types, allowing them to instead continue growing and dividing indefinitely, according to research performed by a team of scientists who have recently joined the stem-cell research efforts at the Keck School of Medicine of the University of Southern California. Their findings are being published in the Proceedings of the National Academy of Sciences. This discovery takes scientists another step closer to being able to grow embryonic stem cells without the “feeder layer” of mouse fibroblast cells that is essential for maintaining the pluripotency of embryonic stem cells. [lien] [EN]

Scientists develop new procedure to differentiate human embryonic stem cells

Scientists have developed a new procedure for the differentiation of human embryonic stem cells, with which they have created the first transplantable source of lung epithelial cells. The method involves the use of protein markers under the control of cell-specific promoters to convert undifferentiated human embryonic stem cells into highly-specialized cells. The human embryonic stem cells were cultured on specially coated dishes and transfected with a lung epithelial gene regulator of a drug selection gene. The process, created in the laboratory of Rick A. Wetsel, Ph.D., a professor of molecular medicine at the Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases (IMM), is described in this week's edition of the Proceedings of the National Academy of Sciences (PNAS). [lien] [EN]

Scientists clone mice from adult skin stem cells

For cells that hold so much promise, stem cells’ potential has so far gone largely untapped. But new research from Rockefeller University and Howard Hughes Medical Institute scientists now shows that adult stem cells taken from skin can be used to clone mice using a procedure called nuclear transfer. The findings are reported in the Feb. 12 online edition of the Proceedings of the National Academy of Sciences. Caption: Using a technique called nuclear transfer, mice were cloned using adult skin stem cells (right) and a more differentiated type of skin cell (left). The mouse on the right is almost two years old and the mouse on the right is one and a half. Credit: Jinsong Li, Postdoc in the Mombaerts Laboratory, Rockefeller University Embryonic stem cells have received the most press for their potential to generate healthy cells and tissues that could replace damaged or diseased organs. [lien] [EN]

Scientists discover new, readily available source of stem cells

Scientists have discovered a new source of stems cells and have used them to create muscle, bone, fat, blood vessel, nerve and liver cells in the laboratory. The first report showing the isolation of broad potential stem cells from the amniotic fluid that surrounds developing embryos was published in Nature Biotechnology. “Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well,” said Anthony Atala, M.D., senior researcher and director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine. Atala announced the breakthrough with colleagues from Wake Forest University School of Medicine and Harvard Medical School. “It has been known for decades that both the placenta and amniotic fluid contain multiple progenitor cell types from the developing embryo. [lien] [EN]

New method for creating inducible stem cells is remarkably efficient

Some of the most challenging obstacles limiting the reprogramming of mature human cells into stem cells may not seem quite as daunting in the near future. Two independent research papers, published by Cell Press in the September 11th issue of the journal Cell Stem Cell, describe new tools that provide invaluable platforms for elucidating the molecular, genetic, and biochemical mechanisms associated with reprogramming. The new findings also offer considerable hope toward making the reprogramming process more therapeutically relevant. Although scientists have successfully reprogrammed mature human skin cells into induced pluripotent stem (iPS) cells by expressing a few key transcription factors. [lien] [EN]

Scientists discover new way to enhance stem cells to stimulate muscle regeneration

Scientists at the Ottawa Hospital Research Institute (OHRI) and the University of Ottawa have discovered a powerful new way to stimulate muscle regeneration, paving the way for new treatments for debilitating conditions such as muscular dystrophy. The research, to be published in the June 5 issue of Cell Stem Cell, shows for the first time that a protein called Wnt7a increases the number of stem cells in muscle tissue, leading to accelerated growth and repair of skeletal muscle. “This discovery shows us that by targeting stem cells to boost their numbers, we can improve the body’s ability to repair muscle tissue,” said senior author Dr. Michael Rudnicki. Dr. Rudnicki is the Scientific Director of Canada’s Stem Cell Network and a Senior Scientist at OHRI and Director of OHRI’s Sprott Centre for Stem Cell Research. [lien] [EN]

Scientists identifies gene that regulates blood-forming fetal stem cells

In the rancorous public debate over federal research funding, stem cells are generally assigned to one of two categories: embryonic or adult. But that’s a false dichotomy and an oversimplification. A new University of Michigan study adds to mounting evidence that stem cells in the developing fetus are distinct from both embryonic and adult stem cells. In the last several years, stem cell researchers have realized that fetal stem cells comprise a separate class. They recognized, for example, that fetal blood-forming stem cells in umbilical cord blood behave differently than adult blood-forming stem cells after transplantation into patients. Now a U-M team led by Sean Morrison has identified the first known gene. [lien] [EN]