Gene identified that helps wound healing

This image shows modulation of wound healing and scar formation by MG53-mediated cell membrane repair and TGF-? signaling regulation.

Credit: Li.et.al., 2015

Researchers at Ohio State University have pinpointed a human gene product that helps to regulate wound healing and may control scarring in people recovering from severe injuries and damage to certain internal organs.

The protein, MG53, travels throughout the bloodstream and helps the body fix injuries to the skin, heart, lungs, kidneys and other organs without causing scars. It’s a discovery that could help heal open wounds, decrease recovery time after surgery and reduce the spread of infections.

“A massive scar on your skin may look bad, but imagine you have a heart attack and get a scar on your heart–that could be lethal,” says Jianjie Ma, a physiologist at Ohio State and co-author of the presentation.

All animals carry this gene, he said, and it’s almost identical no matter which species. MG53 fixes the cell and tissue damage that occurs during everyday living. Even simple actions, like walking or typing, will cause injuries to the body. Usually this isn’t a problem because MG53 can make repairs before there’s any serious harm.

Ma and his team genetically engineered mice without the gene that makes MG53 to see what would happen without its healing capabilities. The experiments showed that the mice lacking MG53 had difficulty recovering from injury, because of their compromised repair capacity; their heart would not function well under stress conditions.

MG53 works in tandem with another protein called TGF Beta, a type of “cytokine” protein that also heals wounds, but the healing process happens so quickly that it causes scars. If you have more TGF Beta in your bloodstream than MG53, you scar easily.

Ma’s goal is to develop a therapy that will inhibit TGF Beta and promote MG53. Medical professionals can use the therapy during procedures to promote quick, scarless healing. His next step is to identify a small compound that can do this and eventually test whether it has the desired effect in human trials.

Presentation #2907, “MG53 promotes wound healing and reduces scar formation by facilitating cell membrane repair and controlling myofibroblast differentiation,” is authored by Haichang Li, Pu Duann, Pei-Hui Lin, Li Zhao, Zhaobo Fan, Tao Tan, Xinyu Zhou, Mingzhai Sun, Matthew Sermersheim, Hanley Ma, Steven Steinberg, Hua Zhu, Chunyu Zeng, Jianjun Guan and Jianjie Ma. It will be in a poster session that begins at 10:30 a.m. on Wed., March 2, 2016 in the West Hall of the Los Angeles Convention Center.

New method reveals high similarity between gorilla and human Y chromosome

Jim (on the right), whose Y chromosome was sequenced, together with Dolly, his mother, and Binti, his sister.

Credit: San Diego Zoo Global

A new, less expensive, and faster method now has been developed and used to determine the DNA sequence of the male-specific Y chromosome in the gorilla. The technique will allow better access to genetic information of the Y chromosome of any species and thus can be used to study male infertility disorders and male-specific mutations. It also can aid in conservation genetics efforts by helping to trace paternity and to track how males move within and between populations in endangered species, like gorillas.

A paper describing the method and the discovery resulting from its use in comparing the sequence of the gorilla Y chromosome to the sequences of the human and chimpanzee Y chromosomes will be published on March 2, 2016 in the Advance Online edition of the journal Genome Research. The article also will be published in the April 2016 print issue of the journal.

“Surprisingly, we found that in many ways the gorilla Y chromosome is more similar to the human Y chromosome than either is to the chimpanzee Y chromosome,” said Kateryna Makova, the Francis R. and Helen M. Pentz Professor of Science at Penn State and one of two corresponding authors of the paper. “In regions of the chromosome where we can align all three species, the sequence similarity fits with what we know about the evolutionary relationships among the species — humans are more closely related to chimpanzees. However, the chimpanzee Y chromosome appears to have undergone more changes in the number of genes and contains a different amount of repetitive elements compared to the human or gorilla. Moreover, a greater proportion of the gorilla Y sequences can be aligned to the human than to the chimpanzee Y chromosome.”

The Y chromosome of mammals is incredibly difficult to sequence for a number of reasons. One reason is that the Y chromosome is present in only one copy and makes up only about one to two percent of the total genetic material found in a cell of a male. To reduce this difficulty, the researchers used an experimental technique called flow-sorting to preferentially select the Y chromosome for sequencing based on the chromosome’s size and genetic content.

“Flow-sorting increased the amount of the Y chromosome in our dataset to about thirty percent,” said Paul Medvedev, assistant professor of computer science and engineering and of biochemistry and molecular biology at Penn State, the other corresponding author of the paper. “To further enrich our data for the Y chromosome, we developed a computational technique — called RecoverY — to sort the data into Y and non-Y sequences based on how frequently similar sequences appeared in our data.”

The Y chromosome, like all DNA, is composed of a series of molecules called “bases” that are represented by the letters A, T, C, and G. Current genetic sequencing technologies produce “reads” of sequence that are much shorter than the entire length of the chromosome. These reads need to be placed in order and pieced together by finding places where they overlap into longer and longer chunks. The research team used two different sequencing technologies to help with this assembly of the DNA sequence of the Y chromosome.

One sequencing technology used by the researchers produces massive amounts of very short reads — about 150 to 250 bases in length. Using this method, the researchers sequenced enough reads to cover the entire length of the Y chromosome about 450 times. The researchers assembled these short reads into longer chunks that they then further connected using the second sequencing technology that produces longer reads — about seven thousand bases in length on average.

“By reducing non-Y chromosome reads from our data with flow sorting and the RecoverY technique that we developed, and by using this combination of sequencing technologies, we were able to assemble the gorilla Y chromosome so that more than half of the sequence data was in chunks longer than about 100,000 bases in length,” said Medvedev.

Another reason that determining the genetic sequence of the Y chromosome is so difficult is that it is composed of an unusually high number of repeated sequences — regions where the sequence of As, Ts, Cs, and Gs are identical, or nearly identical, for thousands or millions of bases in a row. Many of these repeats, including some genes, appear as back-to-back series of the same repeated sequence or as long palindromes which, like the word “racecar,” read the same forward and backward. The researchers used an experimental technique — “droplet digital polymerase chain reaction” — to determine the number of copies of the genes that appear in these series.

“Sequencing the Y chromosome is like trying to put together a jigsaw puzzle, without knowing the final picture, from a pile of pieces where only about one out of every hundred is useful, and most of the pieces you do need look identical,” said Makova. “We’ve developed a pipeline for sequencing the Y chromosome that is more efficient than previous methods and reduces a number of the difficulties associated with determining the genetic sequence of the Y chromosome. Our method will open the door for studying the Y chromosome for more labs, more species, and more individuals within those species.”

To demonstrate the utility of the gorilla Y chromosome sequence they generated, the researchers designed genetic markers that can be used to differentiate the genetic relatedness among male gorillas and thus to aid in conservation genetics efforts targeted at preserving this endangered species.

In addition to Makova and Medvedev, the research team includes Marta Tomaszkiewicz, Samarth Rangavittal, Monika Cechova, Rebeca Campos-Sanchez, Howard W. Fescemyer, Robert Harris, Danling Ye, and Rayan Chikhi at Penn State; Malcom A. Ferguson-Smith and Patricia C. M. O’Brien at the University of Cambridge in the United Kingdom; and Oliver Ryder at the San Diego Zoo.

New weapon in the fight against children’s brain tumors

To create the new mouse model of children’s brain cancer, the researchers caused a mutation that occurs in many tumors, and used special stains to see the difference between healthy brain tissue (red) and the areas where the mutation took hold and a tumor arose (blue/green).

Credit: University of Michigan

Children with brain cancer may soon get some help from mice with the same disease, thanks to new research from University of Michigan Medical School scientists and their colleagues.

In a new paper in Science Translational Medicine, the U-M team describes how they developed a novel brain tumor model in mice.

The mice have the same genetic problems as those seen in many children with the most dangerous forms of brain cancer. That means the mice should be able to serve as a new test bed for treatments aimed at shrinking children’s tumors.

Unlike adults with brain cancer, children cannot receive radiation therapy, so doctors must rely on medications and other strategies. Brain tumors are the leading cause of cancer death in children. A lack of treatment options keeps survival rates low.

“This is exciting because it’s the first animal model of pediatric high-grade gliomas, or malignant brain tumors,” says Maria Castro, Ph.D., senior author of the paper and a professor in the departments of Neurosurgery and Cell and Developmental Biology at U-M. “The mice carry the genetic mutations found in human tumors, and develop tumors that closely resemble what children and adolescents do.”

And unlike previous attempts by others, the model generated at the U-M has a fully functional immune system, which makes it even more alike the children they mimic.

Brain cancer biology
In addition to developing the new genetically engineered mouse model for the form of cancer called glioblastoma multiforme, the researchers made a key discovery about brain tumor biology via the mice. Their work focuses on a protein called ATRX, and its role in helping cells repair damage to DNA. About one-third of children and young adults with brain cancer have ATRX mutations in their cancer cells.

Using a special genetic technique that introduced the same mutation in mice, soon after birth, the scientists were able to generate brain tumors that made less of the ATRX protein. Then, they showed that when the cancer cells didn’t make enough ATRX, the cells couldn’t join together the two ends of a broken DNA strand.

This genetic instability accelerated tumor growth and reduced the survival of mice that went without treatment.

But in an ironic — and potentially beneficial — twist, the researchers also showed that if they treated the mice’s tumors with drugs that damage DNA, they could actually shrink tumors more effectively and improve survival.
DNA-damaging cancer drugs already exist, and are used for other purposes in adults. If further research in the mice bears out, they could soon be tested in children whose brain tumors also show a decrease in ATRX production.

The first author of the study, U-M children’s cancer specialist Carl Koschmann, M.D., helps guide the treatment of children with brain cancer at U-M’s C.S. Mott Children’s Hospital. He also studies brain cancer at the basic cell level in the Castro laboratory.

“We are very excited about this tumor model as it mimics the developmental environment of a pediatric or adolescent human brain tumor,” he says. “We desperately need new therapies for pediatric GBM patients, as less than 20 percent of children diagnosed with GBM will survive five years. We currently base their treatment on a regimen designed for adult patients with GBM, which are very different tumors at the molecular level. Our mouse model has given us a great step towards developing targeted therapies to specific changes found in pediatric and adolescent GBM.”

Accelerating discovery
Dr Castro’s team at U-M, and their colleagues on teams at the Johns Hopkins School of Medicine, the University of Rochester, and the Institute of Cancer Research in London have been working toward this goal for several years.

A crucial aspect of the mouse model development was the ability to use what’s called the “Sleeping Beauty” technique of inserting genes into stem cells in the brain of newborn mice. This allows their brain to develop normally, but also triggers the development of cancer by adding mutated ATRX genes and other genes known to be involved in cancer.

They also looked at genetic data on several hundreds of adult and pediatric brain tumors from around the world. That helped them confirm that mutations in the gene that directs cells to make ATRX are responsible for making the tumors genetically unstable.

Personalizing treatment for brain tumors based on an individual’s ATRX mutation status is still a concept, not a reality. But the researchers believe their mouse model and the close collaboration with pediatric brain cancer treatment teams at Mott Hospital will accelerate the ability to do so.

PET scans reveal key details of Alzheimer’s protein growth in aging brains

Shown are PET scans that track tau (top row) and beta-amyloid from two normal older people and a patient with Alzheimer’s disease (AD). The normal older adult on the left has no brain amyloid deposition and minimal tau in the medial temporal lobe. In the normal older adult in the middle, amyloid deposition is present throughout the brain, and tau has spread out into the temporal cortex. In the AD patient, both amyloid and tau are spread through the brain.

Credit: Michael Schöll

New research led by scientists at the University of California, Berkeley, shows for the first time that PET scans can track the progressive stages of Alzheimer’s disease in cognitively normal adults, a key advance in the early diagnosis and staging of the neurodegenerative disorder.

In the process, the scientists also obtained important clues about two Alzheimer’s-linked proteins — tau and beta-amyloid — and how they relate to each other.

The findings, to be published March 2 in the journal Neuron, come from positron emission tomography (PET) of 53 adults. Five were young adults aged 20-26, 33 were cognitively healthy adults aged 64-90, and 15 were patients aged 53-77 who had been diagnosed with probable Alzheimer’s dementia.

The stages of tau deposition were established by German researchers Heiko and Eva Braak through postmortem analysis of the brains of suspected Alzheimer’s patients.

“Braak staging was developed through data obtained from autopsies, but our study is the first to show the staging in people who are not only alive, but who have no signs of cognitive impairment,” said study principal investigator Dr. William Jagust, a professor at UC Berkeley’s School of Public Health and at the Helen Wills Neuroscience Institute and a faculty scientist at Lawrence Berkeley National Laboratory. “This opens the door to the use of PET scans as a diagnostic and staging tool.”

PET scans are used to detect early signs of disease by looking at cellular-level changes in organs and tissue. The results of the scans in this study paralleled Braak neuropathological stages, which range from 1 to 6, describing the degree of tau protein accumulation in the brain.

Jagust worked with study co-lead authors Michael Schöll, a visiting scholar, and Samuel Lockhart, a postdoctoral fellow, both at UC Berkeley’s Helen Wills Neuroscience Institute.

Tau vs. amyloid
Their findings also shed light on the nature of tau and amyloid protein deposits in the aging brain. For many years, the accumulation of beta amyloid plaques was considered the primary culprit in Alzheimer’s disease. Over the past decade, however, tau, a microtubule protein important in maintaining the structure of neurons, has emerged as a major player. When the tau protein gets tangled and twisted, its ability to support synaptic connections becomes impaired.

While a number of symptoms exist that signal Alzheimer’s disease, a definitive diagnosis has been possible only through an examination of the brain after the patient has died. The availability of amyloid imaging for the past decade has improved this situation, but how Alzheimer’s developed as a result of amyloid remains a mystery. Studies done in autopsies linked the development of symptoms to the deposition of the tau protein.

Through the PET scans, the researchers confirmed that with advancing age, tau protein accumulated in the medial temporal lobe — home to the hippocampus and the memory center of the brain.

“Tau is basically present in almost every aging brain,” said Schöll, who holds an appointment at Sweden’s University of Gothenburg. “Very few old people have no tau. In our case, it seems like the accumulation of tau in the medial temporal lobe was independent of amyloid and driven by age.”

The study revealed that higher levels of tau in the medial temporal lobe were associated with greater declines in episodic memory, the type of memory used to code new information. The researchers tested episodic memory by asking subjects to recall a list of words viewed 20 minutes earlier.

Both proteins involved in dementia
One question yet to be answered is why so many people who have tau in their medial temporal lobe never go on to develop Alzheimer’s. Likewise, adults may have beta amyloid in their brains and still be cognitively healthy.
“It’s not that one is more important than the other,” said Lockhart. “Our study suggests that they may work together in the progression of Alzheimer’s.”

While higher levels of tau in the medial temporal lobe were linked to more problems with episodic memory, it was when tau spread outside this region to other parts of the brain, such as the neocortex, that researchers saw more serious declines in global cognitive function. Significantly, they found that tau’s spread outside the medial temporal lobe was connected to the presence of amyloid plaques in the brain.

“Amyloid may somehow facilitate the spread of tau, or tau may initiate the deposition of amyloid. We don’t know. We can’t answer that at this point,” said Jagust. “All I can say is that when amyloid starts to show up, we start to see tau in other parts of the brain, and that is when real problems begin. We think that may be the beginning of symptomatic Alzheimer’s disease.”

What the study does indicate, the researchers said, is that tau imaging could become an important tool in helping to develop therapeutic approaches that target the correct protein — either amyloid or tau — depending on the disease stage.

Platelet-rich plasma injections may lead to improvements in tissue healing

Dr. Marni Wesner performs a platelet-rich plasma injection procedure on a patient at the University of Alberta Glen Sather Sports Medicine Clinic.

Credit: University of Alberta

Tiger Woods, Kobe Bryant and A-Rod have all used it, but does platelet-rich plasma therapy (PRP) really work for the every-day active person? According to a University of Alberta Glen Sather Sports Medicine Clinic pilot study on patients with chronically sore shoulders published in PLOS ONE, preliminary findings say yes.

“We studied patients 35 to 60 years old with rotator cuff tendinopathy due to normal aging. For the first time, we were able to not only find reported improvements in pain and mobility, but also in the tissue — the MRI before and after showed structural change and a decrease in the size of tears,” says Marni Wesner, sports medicine physician at the Glen Sather Sports Medicine Clinic and lead author of the study.

Platelet-rich plasma injection (PRP) is an emerging therapeutic procedure in medicine and rehabilitation for the treatment of both acute and chronic soft tissue injuries. It involves collecting blood from the patient’s arm, separating the platelets via centrifuge and injecting it back into the patient’s injured tissue area to augment (or facilitate) the body’s natural healing response.

Platelets are cells that clot blood and contain over 300 active growth factors. In tissues that are aging and do not repair and regenerate well, growth factors may help to improve healing by creating an environment to foster healing and regeneration of tissue.

Though this is a pilot study on a small number of patients, the outcomes are still clinically relevant and this is the first time researchers have described structural change in the healing process as well as improvement in the patients’ pain and function.

“Based on MRI findings before and after the injections, we saw improvements in the tissue six months later in five of seven patients undergoing PRP and an appropriate rehabilitation program. The healing in the tissue appeared to correspond with the reported improvement of the pain and also with the clinical assessment of function,” explains Doug Gross, interim chair of physical therapy at the Faculty of Rehabilitation Medicine and corresponding author of the study.

For retired police officer Debbie Brown who is a participant in the study, this healing from PRP made all the difference in her life.

“For the past two years, I have tried everything for my right shoulder. Physio would help for a bit but then the problem would still be there. I tried acupuncture, Kinesio tape, cortisol injections — you name it, I’ve tried it,” says Brown. “Once I did the PRP, it really did fix everything!”

Brown says she did physical therapy with Heather Bredy at the Glen Sather Sports Medicine Clinic as part of her treatment and continues to do exercises regularly. Besides a bit of soreness here and there — she says she is 58, after all! — her shoulder is like new.

“I can shoulder-check now and brush my hair. I can work out and be active again,” she says.

Wesner says it’s important to note that to be considered for PRP at the Glen Sather Sports Medicine Clinic, the patient must be referred by a physician.

“The sports medicine physicians at the Glen Sather Sports Medicine Clinic always recommend and provide more conservative or ‘traditional’ care first, and appropriate rehabilitation along with the PRP injections” she says. “The Glen Sather Sports Medicine Clinic has done more than 600 PRP treatments on a variety of tendons and soft tissue areas. PRP injections at the clinic are ultra-sound guided.”

Gross, also the director of the Rehabilitation Research Centre, says PRP therapy is becoming more widespread and the next step in research is to study its effectiveness in larger, well-designed controlled clinical trials. “This pilot study has shown promising results and important experience for planning subsequent studies.”

As for Brown who’s had renewed function and healing in her shoulder, she can’t stop telling her friends and colleagues to go to the Glen Sather Clinic at the U of A.

“PRP makes me feel like I’m in my 20s!” she smiles.