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Posts Tagged ‘Cell type’

PLURIPOTENT CELLS DISCOVERED IN ADULT BREAST TISSUE

In STEM CELLS IN THE NEWS on March 12, 2013 at 9:00 am

epscolony

The top middle panel shows endogenous pluripotent somatic (ePS) cells, which can give rise to many tissue derivatives, including pancreas, bone, intestine, breast and cartilage cells.

“More evidence that any part of the body associated with reproduction has powerful stem cells with significant regenerative abilities!” – DG

New Type of Pluripotent Cell Discovered In Adult Breast Tissue

UC San Francisco researchers have found that certain rare cells extracted from adult breast tissue can be instructed to become different types of cells – a discovery that could have important potential for regenerative medicine.  As with human embryonic stem cells, the newly found cells are pluripotent, or capable of turning into most cell types, the authors said. The scientists discovered that when the cells were put either in mice, or in cell culture, the cells could differentiate to produce multiple cell types, including those that proceed to make heart, intestine, brain, pancreas and even cartilage.  The finding is significant, the authors said, because scientists previously believed that pluripotent cells did not exist in the body after the embryonic stage of human development.

“The ability of cells from an adult body to make so many tissue derivatives was completely unexpected,” said senior author Thea D. Tlsty, PhD, a UCSF professor of pathology. “When we saw that they could make cartilage, bone, gut, brain, pancreas cells – and even beating heart tissue – we were excited and intrigued.”

Though the newly discovered cells share some characteristics of embryonic stem cells, they appear to be unique to themselves, said Tlsty. They are mortal and genetically stable – characteristics that are barriers to subsequent cancer formation, which is a factor that could prove valuable if the cells are to be used for regenerative medicine, she explained. By contrast, human embryonic stem cells as well as engineered induced pluripotent stem cells, also known as iPS cells, are immortal and genetically unstable.

Additionally, the cells can expand to an extensive yet finite number before they stop growing. One cell can grow for almost 60 population doublings, producing in excess of one billion daughter cells, conceptually providing enough cells to help in the recovery of damaged or diseased tissue.  The scientists are currently searching for the rare cells in other organs of the body. They hypothesize that these “universal patch kits” are scattered throughout the body of adult men and women.

The special cells were discovered and isolated in healthy breast tissue from women of various ages and ethnicities who were undergoing breast reductions. All tissues used in the study were devoid of visible disease or contamination.

From Breast Tissue to Beating Heart Cells

Even a single one of these endogenous pluripotent somatic (ePS) cells, when placed in the appropriate conditions, exhibited the same pluripotent power to self-renew and to generate multiple lineages – both in vitro and in vivo – as embryonic stem cells. The cells could develop into any of the three germ layers: endoderm (such as the pancreas and gastrointestinal tract), the mesoderm (bone, heart muscle, blood vessel), or ectoderm (breast tissues and nervous system).

For example, when properly instructed, some ePS cells made human breast tissue that produced milk in transplanted mice, while other cells generated cartilage structures. To the surprise of the researchers, when the cells were differentiated into heart muscle, they even demonstrated the spontaneous beating seen in cardiomyocytes, or “beating heart” cells.

“The cells we describe here exist in the body devoid of commitment,” the authors wrote. “Taken together, these studies provide morphological, molecular and functional evidence of lineage plasticity of these cells. They will make human milk, bone, fat – they will beat like a heart.”

Only a small fraction of certain mammary cells have “this complete and sustained” unique profile capable of morphing themselves, the researchers said.

“Future research will tell us if we lose access to these cells as we age, if they are found in all tissues, and if they can be used to rescue diseased tissues,” said Tlsty.

“The observation that rare cells within an adult human body have the capacity to differentiate into many tissue types under different physiological cues will facilitate a fascinating area of research into the physiology and therapeutic potential of these cells,” said lead author Somdutta Roy, PhD, Department of Pathology and the UCSF Helen Diller Family Comprehensive Cancer Center.

To read entire article – http://www.ucsf.edu

STASH OF STEM CELLS FOUND IN A HUMAN PARASITE

In SCIENCE & STEM CELLS, STEM CELLS IN THE NEWS on February 25, 2013 at 9:00 am
A composite image of a scanning electron micrograph of a pair of male and female Schistosoma mansoni with the outer tegument (skin) of the male worm "peeled back" (digitally) to reveal the stem cells (orange) underneath.

A composite image of a scanning electron micrograph of a pair of male and female Schistosoma mansoni with the outer tegument (skin) of the male worm “peeled back” (digitally) to reveal the stem cells (orange) underneath.

Stash of Stem Cells Found in a Human Parasite

The parasites that cause schistosomiasis, one of the most common parasitic infections in the world, are notoriously long-lived. Researchers have now found stem cells inside the parasite that can regenerate worn-down organs, which may help explain how they can live for years or even decades inside their host.

Schistosomiasis is acquired when people come into contact with water infested with the larval form of the parasitic worm Schistosoma, known as schistosomes. Schistosomes mature in the body and lay eggs that cause inflammation and chronic illness. Schistosomes typically live for five to six years, but there have been reports of patients who still harbor parasites decades after infection.  According to new research from Howard Hughes Medical Institute (HHMI) investigator Phillip Newmark, collections of stem cells that can help repair the worms’ bodies as they age could explain how the worms survive for so many years. The new findings were published online on February 20, 2013, in the journal Nature.

The stem cells that Newmark’s team found closely resemble stem cells in planaria, free-living relatives of the parasitic worms. Planaria rely on these cells, called neoblasts, to regenerate lost body parts. Whereas most adult stem cells in mammals have a limited set of possible fates—blood stem cells can give rise only to various types of blood cells, for example —planarian neoblasts can turn into any cell in the worm’s body under the right circumstances.  Newmark’s lab at the University of Illinois at Urbana-Champaign has spent years focused on planaria, so they knew many details about planarian neoblasts —what they look like, what genes they express, and how they proliferate. They also knew that in uninjured planarians, neoblasts maintain tissues that undergo normal wear and tear over the worm’s lifetime.

“We began to wonder whether schistosomes have equivalent cells and whether such cells could be partially responsible for their longevity,” says Newmark.

Following this hunch, and using what they knew about planarian neoblasts, post-doctoral fellow Jim Collins, Newmark, and their colleagues hunted for similar cells in Schistosoma mansoni, the most widespread species of human-infecting schistosomes.  Their first step was to look for actively dividing cells in the parasites. To do this, they grew worms in culture and added tags that would label newly replicated DNA as cells prepare to divide; this label could later be visualized by fluorescence. Following this fluorescent tag, they saw a collection of proliferating cells inside the worm’s body, separate from any organs.

The researchers isolated those cells from the schistosomes and studied them individually. They looked like typical stem cells, filled with a large nucleus and a small amount of cytoplasm that left little room for any cell-type-specific functionality. Newmark’s lab observed the cells and found that they often divided to give rise to two different cells: one cell that continued dividing, and another cell that did not.  “One feature of stem cells,” says Newmark, “is that they make more stem cells; furthermore, many stem cells undergo asymmetric division.” The schistosomes cells were behaving like stem cells in these respects. The other characteristic of stem cells is that they can differentiate into other cell types.  To find out whether the schistosome cells could give rise to multiple types of cells, Newmark’s team added the label for dividing cells to mice infected with schistosomes, waited a week, and then harvested the parasites to see where the tag ended up. They could detect labeled cells in the intestines and muscles of the schistosomes, suggesting that stem cells incorporating the labels had developed into both intestinal and muscle cells.

Years of previous study on planarians by many groups paved the way for this type of work on schistosomes, Newmark says.

“The cells we found in the schistosome look remarkably like planarian neoblasts. They aren’t associated with any one organ, but can give rise to multiple cell types. People often wonder why we study the ‘lowly’ planarian, but this work provides an example of how basic biology can lead you, in unanticipated and exciting ways, to findings that are directly relevant to important public health problems.”

Newmark says the stem cells aren’t necessarily the sole reason schistosome parasites survive for so many years, but their ability to replenish multiple cell types likely plays a role. More research is needed to find out how the cells truly affect lifespan, as well as what factors in the mouse or human host spur the parasite’s stem cells to divide, and whether the parasites maintain similar stem cells during other stages of their life cycle.

The researchers hope that with more work, scientists will be able to pinpoint a way to kill off the schistosome stem cells, potentially shortening the worm’s lifespan and treating schistosome infections in people.

http://www.sciencedaily.com

THREE TYPES OF TASTE CELLS DISCOVERED THROUGH A SINGLE TYPE OF STEM CELL

In ALL ARTICLES, SCIENCE & STEM CELLS, STEM CELLS IN THE NEWS on February 7, 2013 at 9:00 am

tongue

A Single Type Of Stem Cell Give Rise To Three Types Of Taste Cells

As stem cell research progresses, scientists are becoming more and more specialized in studying the types of cells and tissues that they generate.  In pursuing the mechanisms that drive stem cell specialization, scientists at the Monell Chemical Senses Center in Philadelphia have identified certain genetic characteristics of taste stem cells and their location on the tongue, according to their report in the journal Stem Cells.

“Cancer patients who have taste loss following radiation to the head and neck and elderly individuals with diminished taste function are just two populations who could benefit from the ability to activate adult taste stem cells,” said study co-author Dr. Robert Margolskee, a molecular neurobiologist at Monell.

Taste stems cells differentiate into three different types of taste cells, all of which are found within the tiny taste buds that dot the tongue. Two types of taste cells, also referred to as gustatory cells, contain chemoreceptors that convey the various kinds of taste, including bitter, sweet, sour and umami. The third type of taste cell performs more of a structural function.

One of the remarkable properties of taste cells is their ability to regenerate. All three kinds of cells last about 10 to 16 days before being shed in favor of their replacements.  Scientists have been working for decades to find out how taste bud cells develop and regularly regenerate. They were uncertain how many cells were involved in the process and where these cells are located.  The researchers initially hypothesized that a clue to identifying taste stem cells could be found in the physiologically similar endocrine cells located in the intestine. The intestinal stem cells are easily stained using a marker known as Lgr5.

When the same stain was used on taste tissues, it showed two different patterns. The first pattern was a strong signal under the raised protrusions at the back of the tongue’s surface known as taste papillae. The second, weaker signal pattern was located immediately underneath taste buds in those same papillae.

In their report, the scientists concluded that the two different levels of expression could mean there are two different populations of cells. They said that the cells with the stronger expression of Lgr5 could be the true taste stem cells, while those with the weaker expression could be those stem cells that are slowly transforming into functional taste cells.

Using lineage-tracing experiments, the Monell scientists were also able to discover that a single type of stem cell gives rise to all three types of taste cells. “This is just the tip of the iceberg,” said senior author Peihua Jiang, a molecular neurobiologist at Monell. “Identification of these cells opens up a whole new area for studying taste cell renewal, and contributes to stem cell biology in general.” According to the research center, future taste stem cell studies will be focused on identifying how the Lgr5-expressing cells differentiate into the different kinds of taste cell types. They said they also plan to grow these cells in culture, for research and clinical use.

redorbit.com

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