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Posts Tagged ‘Cell potency’

MUSCLE REPAIR THROUGH STEM CELLS

In SCIENCE & STEM CELLS, STEM CELLS IN THE NEWS on March 13, 2013 at 9:00 am

Researchers from the University of Minnesota Use Genetically Corrected Stem Cells To Repair Muscles

University of Minnesota researchers from the Lillehei Heart Institute have combined genetic engineering techniques to repair mutations in abnormal muscle cells with cellular reprogramming to generate stem cells that can repair and regenerate muscle regeneration in a mouse model for Duchenne Muscular Dystrophy (DMD). This research is a proof-of-principle experiment that determines the feasibility of combining induced pluripotent stem cell technology and genetic engineering techniques that correct mutations to treat muscular dystrophy. Experimental strategies such as these could represent a major step forward in autologous cell-based therapies for DMD. Furthermore, it might pave the way for clinical trials to test this approach in reprogrammed human pluripotent cells from muscular dystrophy patients.

University of Minnesota researchers combined three groundbreaking technologies to achieve effective muscular dystrophy therapy in a mouse model of DMD. First, researchers reprogrammed skin cells into induced pluripotent stem cells (iPSCs). iPSCs are capable of differentiating into any of the mature cell types within an adult organism. In this case, the University of Minnesota researchers generated pluripotent cells from the skin of mice that carry mutations in two genes; the dystrophin and utrophin genes. Mice with mutations in both the dystrophin and utrophin genes develop a severe case of muscular dystrophy that resembles the type of disease observed in human DMD patients. This provided a model system platform that successfully mimicked what would theoretically occur in humans.

The second technology employed is a genetic correction tool developed at the University of Minnesota. In this case, they used a transposon, which is a segment of DNA that can jump from one location to another within the genome. The specific transposon used is the “Sleeping Beauty Transposon.” The use of this transposon allowed them to transport genes into cells in a convenient manner. The Lillehei Heart Institute researchers used the Sleeping Beauty transposon to deliver a gene called “micro-utrophin” into the iPSCs made from the DMD mice.

Sleeping Beauty Transposon

Human micro-utrophin can support muscle fiber strength and prevent muscle fiber injury throughout the body. However, there is one essential difference micro-utrophin and dystrophin: dystrophin is absent in muscular dystrophy patients, but if it is introduced into the bodies of DMD patients, their immune system will initiate a devastating immune response against it. However, in those same patients, utrophin is active and functional, which makes it essentially “invisible” to the immune system. This invisibility allows the micro-utrophin to replace dystrophin build and repair muscle fibers within the body.

Utrophin

The third technology utilized is a method to produce skeletal muscle stem cells from pluripotent cells. This procedure was developed in the laboratory of Rita Perlingeiro, who is also the principal investigator of this latest study.

Perlingeiro’s technology gives pluripotent cells a short pulse of a muscle stem cell protein called Pax3, which nudges the pluripotent cells to become skeletal muscle stem cells, which can then be exponentially expanded in culture. These Pax3-induced muscle stem cells were then transplanted back into the same strain of DMD mice from which the pluripotent stem cells were originally derived.

Pax3 and 7

When combined, these platforms created muscle-generating stem cells that would not be rejected by the body’s immune system. According to Perlingeiro, the transplanted cells performed very well in the dystrophic mice, and they generated functional muscle and responded to muscle fiber injury.

“We were pleased to find the newly formed myofibers expressed the markers of the correction, including utrophin,” said Perlingeiro, a Lillehei endowed scholar within the Lillehei Heart Institute and an associate professor in the University of Minnesota Medical School. “However, a very important question following transplantation is if these corrected cells would self-renew, and produce new muscle stem cells in addition to the new muscle fibers.”

By injuring the transplanted muscle and watching it repair itself, the researchers demonstrated that the transplanted muscle stem cells endowed the recipient mice with fully functional muscle cells. This latest project provides the proof-of-principle for the feasibility of combining induced pluripotent stem cell technology and genetic correction to treat muscular dystrophy.

“Utilizing corrected induced pluripotent stem cells to target this specific genetic disease proved effective in restoring function,” said Antonio Filareto, Ph.D., a postdoctoral fellow in Perlingeiro’s laboratory and the lead author on the study. “These are very exciting times for research on muscular dystrophy therapies.”

These studies pave the way for testing this approach in a clinical trial that would use reprogrammed human pluripotent cells from muscular dystrophy patients.

According to Perlingeiro, “Developing methods to genetically repair muscular dystrophy in human cells, and demonstrating efficacy of muscle derived from these cells are critical near-term milestones, both for the field and for our laboratory. Testing in animal models is essential to developing effective technologies, but we remained focused on bringing these technologies into use in human cells and setting the stage for trials in human patients.”

This research was published in Nature Communications.

Article written by: mburatov

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

BRAIN CELLS DERIVED FROM URINE

In STEM CELLS IN THE NEWS on December 15, 2012 at 8:58 am

scells

“Scientists have been successfully deriving stem cells from ordinary human cells for years.  Researchers have reprogrammed testicle stem cells to make insulin and even harvested adult stem cells from the scalps and brain linings of human corpses.  A recent study published in the journal Natural Methods, showcases the ability to take kidney cells that are shed and excreted through urine and transform them into brain stem cells, without the unpredictable threat of tumors when transplanted to the host.  This new method could be useful in treating neurodegenerative diseases, such as Parkinson’s and Alzheimer’s.”

-DG

The technique is described in a study that was published in the journal Nature Methods (Wang, et al., Nature Methods (2012) doi:10.1038/nmeth.2283). Unlike embryonic stem cells, which are derived through the destruction of embryos and have the potential to cause tumors, these neural progenitor cells do not form tumors and are made quickly and without the destruction of human embryos.

Stem cell biology expert Duanqing Pei and his co-workers from China’s Guangzhou Institutes of Biomedicine and Health, which is part of the Chinese Academy of Sciences, previously published a paper that showed that epithelial cells from the kidney that are sloughed into urine can be reprogrammed into induced pluripotent stem cells (iPSCs) (Ting Zhou, et al., Journal of the American Society of Nephrology 2011 vol. 22 no. 7 1221-1228, doi: 10.1681/ASN.2011010106). In this study, Pei and his colleagues used retroviruses to insert pluripotency genes into kidney-based cells to reprogram them. Retroviruses are efficient vectors for genes transfer, but they insert their virus genomes into the genomes of the host cell. This insertion event can cause mutations, and for this reason, retroviral-based introduction of genes into cells are not the preferred way to generate iPSCs for clinical purposes.

Researchers use retroviruses to routinely reprogram cultured skin and blood cells into iPSCs, and these iPSCs can be differentiated into any adult cell type. However, urine is a much more accessible source of cells.

In this present study, Pei’s team used a different technique to introduce genes into the cells from urine; they used “episomal vectors,” which is an overly fancy way of saying that they placed the pluripotency genes on small circles of DNA that were then pushed into the cells. Episomal vectors can reprogram adult cells into iPSCs, but they do so at lower levels of efficiency. Nevertheless, episomal vectors have an added advantage in that the vectors transiently express the pluripotency genes in cells and then are lost without inserting into the host cell genome. This makes episomal vectors inherently safer for clinical purposes.

In one of their experiments, perfectly round colonies of reprogrammed cells from urine that resembled pluripotent stem cells after only 12 days. This is exactly half the time typically required to produce iPSCs. When cultured further, the colonies assumed a rosette shape that is common to neural stem cells.

When Pei and others cultured his urine-derived iPSCs in a culture conditions that normally used for cultured neurons, these cells formed functional neurons in the lab. Could these cells work in the brain of a laboratory animal? Transplantation of these cells into the brains of newborn rats showed that, first of all, they did not form tumors, and, secondly, they took on the shape of mature neurons and expressed the molecular markers of neurons.

The beauty of this experiment is that neural progenitors cells (NPCs) grow in culture and researchers can generate buckets of cells for experiments. However, when cells are directly reprogrammed to neurons, even though they make neurons faster than iPSCs.

James Ellis, a medical geneticist at Toronto’s Hospital for Sick Children in Ontario, Canada who makes patient-specific iPSCs to study autism-spectrum disorders, said: “This could definitely speed things up.”

Another plus of this study is that urine can be collected from nearly any patient and banked to produce instant sources of cells from patients, according to geneticist Marc Lalande, who creates iPSCs to study inherited neurological diseases at the University of Connecticut Health Center in Farmington. Lalande is quite intrigued by the possibility of making iPSCs and NPCs from urine draw from the same patient. Lalande added: “We work on childhood disorders,” he says. “And it’s easier to get a child to give a urine sample than to prick them for blood.”

Source:  http://beyondthedish.wordpress.com/2012/12/12/making-brain-cells-from-urine/

MULTIPOTENT STROMAL STEM CELLS FROM PLACENTAL TISSUE DEMONSTRATE HIGH THERAPEUTIC POTENTIAL

In STEM CELLS IN THE NEWS on December 11, 2012 at 9:00 am

placenta

Scientists at Children’s Hospital Oakland Research Institute (CHORI) led by Vladimir Serikov, MD, PhD, and Frans Kuypers, PhD, report in the current Epub issue of Stem Cells Translational Medicine that placental stem cells with important therapeutic properties can be harvested in large quantities from the fetal side of human term placentas called the chorion.

The chorion is a part of the afterbirth and is normally discarded after delivery, but it contains stem cells of fetal origin that appear to be pluripotent — i.e., they can differentiate into different types of human cells, such as lung, liver, or brain cells. Since these functional placental stem cells can be isolated from either fresh or frozen term human placentas, this implies that if each individual’s placenta is stored at birth instead of thrown away, these cells can be harvested in the future if therapeutic need arises. This potential represents a major breakthrough in the stem cell field.

In previous work, Drs. Serikov and Kuypers reported a novel technology to harvest blood-forming stem cells from the placenta to augment cord blood cells. These cells are “siblings” of the cord blood derived stem cells. Cord blood stem cells, unlike embryonic stem cells, have been used for many hundreds of successful bone marrow transplants. These transplants are mainly performed in children, as the amount of cells that can be harvested from cord blood is usually not sufficient for a successful transplant in adults. Adding placental-derived stem cells to the cord blood stem cells could make successful adult bone marrow transplants routinely possible.

The current report demonstrates that placental stem cells have much broader therapeutic potential than bone-marrow transplants, because they are pluripotent — i.e. able to differentiate into many different cell types — and they also generate growth factors that help in tissue repair. These cells are shown to integrate into different tissues when transplanted into mice, but like cord blood stem cells, and in contrast to embryonic pluripotent stem cells, they do not form tumor-like structures in mice.

Placental-derived stem cells are often viewed as “adult” stem cells in contrast to “embryonic” stem cells, which are the dominant focus in the stem cell research field. However, this report shows that these fetal stem cells can be harvested in large numbers, and without the ethical concerns attached to the use of embryonic stem cells. These stem cells may thus be a more practical source for regenerative medicine, particularly since, if placentas are routinely saved instead of thrown away, each individual will be able to draw on their own fetal stem cells if future therapeutic needs arise.

Placental stem cells are only 9 months old, and in contrast to adult stem cells, do not need to be reprogrammed to become pluripotent. Placental-derived stem cells have characteristics of young and vigorous cells, including young mitochondria. Future research will be aimed to bring this to the clinic and to test their efficacy in translational therapeutic applications.

 

http://www.sciencedaily.com/releases/2012/05/120518132250.htm

Embryonic Pluripotency May Give Up Secrets – But So What?

In STEM CELLS IN THE NEWS on July 20, 2012 at 4:07 am

More forward looking statements (without any of the standard legalese on risks, assumptions and uncertainty) regarding the great mystery of embryonic stem cells maybe, sort of, perhaps, soon to give up it’s secrets.

So what’s the deal? 

“Pluripotency is defined as the capacity of individual cells to initiate all lineages of the mature organism in response to signals from the embryo or cell culture environment.”1

Embryonic stem cells have pluripotency.  Discovery of the methods and aspects which allow for pluripotency in embryonic stem cells are definitely a research milestone and one which will advance many lines of inquiry in various fields of medicine…but…there are a few major issues, particularly in the USA.

  • There are already ADULT stem cells which ARE PLURIPOTENT and can be used for treatment. 
  • The US is in a bitter tug of war in both accurate media coverage of stem cells and research and use of adult versus embryonic stem cells. 
  • Pharma is trying to make drugs out of this stuff and get patents on it.
  • In most cases, your own body can supply the necessary stem cells for your own treatment. 
  • And of course, the controversy issues of utilizing embryonic stem cells which will cause the religious right to exert huge resistance on any advancement of embryonic stem cell research in the US.

While the US is still playing a game of catch up in adult and embryonic research and especially treatment; please remember, embryonic stem cell research was fully funded with government backing in many countries around the world for over a decade resulting in…

ZERO EMBRYONIC STEM CELL TREATMENTS.

So don’t get your hopes up for embryonic treatment anytime soon, but then again,

SO WHAT!

ADULT stem cells are here, now, powerful, safe and effective.  What are you waiting for?

Mechanisms That Allow Embryonic Stem Cells to Become Any Cell in the Human Body Identified

ScienceDaily (July 18, 2012) — New research at the Hebrew University of Jerusalem sheds light on pluripotency — the ability of embryonic stem cells to renew themselves indefinitely and to differentiate into all types of mature cells. Solving this problem, which is a major challenge in modern biology, could expedite the use of embryonic stem cells in cell therapy and regenerative medicine.

If scientists can replicate the mechanisms that make pluripotency possible, they could create cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer’s, Parkinson’s, diabetes and other degenerative diseases.

To shed light on these processes, researchers in the lab of Dr. Eran Meshorer, in the Department of Genetics at the Hebrew University’s Alexander Silberman Institute of Life Sciences, are combining molecular, microscopic and genomic approaches. Meshorer’s team is focusing on epigenetic pathways — which cause biological changes without a corresponding change in the DNA sequence — that are specific to embryonic stem cells.

The molecular basis for epigenetic mechanisms is chromatin, which is comprised of a cell’s DNA and structural and regulatory proteins. In groundbreaking research performed by Shai Melcer, a PhD student in the Meshorer lab, the mechanisms which support an “open” chromatin conformation in embryonic stem cells were examined. The researchers found that chromatin is less condensed in embryonic stem cells, allowing them the flexibility or “functional plasticity” to turn into any kind of cell.

A distinct pattern of chemical modifications of chromatin structural proteins (referred to as the acetylation and methylation of histones) enables a looser chromatin configuration in embryonic stem cells. During the early stages of differentiation, this pattern changes to facilitate chromatin compaction.

But even more interestingly, the authors found that a nuclear lamina protein, lamin A, is also a part of the secret. In all differentiated cell types, lamin A binds compacted domains of chromatin and anchors them to the cell’s nuclear envelope. Lamin A is absent from embryonic stem cells and this may enable the freer, more dynamic chromatin state in the cell nucleus. The authors believe that chromatin plasticity is tantamount to functional plasticity since chromatin is made up of DNA that includes all genes and codes for all proteins in any living cell. Understanding the mechanisms that regulate chromatin function will enable intelligent manipulations of embryonic stem cells in the future.

“If we can apply this new understanding about the mechanisms that give embryonic stem cells their plasticity, then we can increase or decrease the dynamics of the proteins that bind DNA and thereby increase or decrease the cells’ differentiation potential,” concludes Dr. Meshorer. “This could expedite the use of embryonic stem cells in cell therapy and regenerative medicine, by enabling the creation of cells in the laboratory which could be implanted in humans to cure diseases characterized by cell death, such as Alzheimer’s, Parkinson’s, diabetes and other degenerative diseases.”

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