Recent research from University of Copenhagen sheds light on previously unknown facts about muscular dystrophy at molecular level. The breakthrough is hoped to improve future diagnosis and treatment of the disease. Researchers have developed a method that will make it easier to map the proteins that have an important kind of sugar monomer, mannose, attached. This is an important finding, as mannose deficiency can lead to diseases such as muscular dystrophy.
About 3,000 people in Denmark suffer from one of the serious muscle-related diseases that come under the heading of muscular dystrophy. Some patients diagnosed with muscular dystrophy die shortly after birth, others become severely retarded and develop eye problems, while certain groups are confined to life in a wheelchair. Common to all muscular dystrophy sufferers is the difficulty of their muscle cells to attach themselves to each other and to the surrounding tissue. However, little is actually known about the root causes of the disease.

New basic research from University of Copenhagen now offers insight into previously unknown facts about muscular dystrophy that may improve future diagnosis and treatment of the disease.

‘Our new research findings may shed light on some of the cellular processes that take place in connection with, for example, muscular dystrophy. This is important information because it is crucial for us to gain as detailed an understanding as possible about the individual cell components. Although the journey from the current basic research to any potential treatment options or diagnostic tools is a long one, our discoveries give grounds for optimism,’ says postdoc Malene Bech Vester-Christensen – who carried out the new experiments from her base at the Faculty of Health and Medical Sciences, University of Copenhagen, and has since taken up a research position at Novo Nordisk.
The new method developed by researchers makes it easier to map the proteins that The protein previously associated with muscular dystrophy is a so-called glycoprotein – a protein with chains of sugar molecules attached. The special kind of sugar attached to these glycoproteins is called mannose. A functional pathway for binding mannose to the proteins is key to the functioning of the human organism, and genetic defects in the process that attaches mannose to the proteins – known as O-mannosylation – can lead to diseases such as muscular dystrophy.

‘To date, only one single protein has been identified and characterised where the mannose deficiency on the protein leads to muscular dystrophy, but our method enables us to faster identify many new proteins that have mannose attached and therefore potentially play a key role for the disease,’ says Adnan Halim, who is associated with the research project and a postdoc with the Danish National Research Foundation, Copenhagen Center for Glycomics. University of Copenhagen

The genetic disease ARVC leads to sudden cardiac death and is more common than it has been hitherto assumed. This is reported by an international team of researchers headed by Prof Dr Hendrik Milting from the Heart and Diabetes Center NRW. The molecular biologist working at the Ruhr-Universität’s clinic in Bad Oeynhausen revealed that all families who are known to be affected by the disease share the same genetic origin. There must be other families in Europe who also carry the genetic mutation but who are not yet known.
Scientists have thrown light on the genetic mutation that causes a particularly severe genetic disease (ARVC5) on the Canadian island Newfoundland in 2008. At first, they assumed that it was a genetic anomaly limited to this Canadian province. In 2010, Milting’s team – and at the same time a team of researchers from Copenhagen – proved that the ‘Newfoundland mutation’ did also occur in Europe. Today, the scientists know about affected families in Germany, Denmark, the USA and Canada. They all share common ancestors, as was demonstrated through genetic analysis. The scientists studied the environment of the TMEM43 gene in which the ARVC5-specific mutation is located. The genetic sequence in the neighbourhood of TMEM43 is typically highly variable; in all affected families, however, it was identical over long stretches. These findings verify a shared genetic origin.
The affected Danish and German families are not aware of the degree to which they are related; according to calculations, the mutation originated some 1300 to 1500 years ago. Thus, the ARVC5 mutation in the European families is not a novel mutation but an old European heritage. Therefore, there must be other families with that genetic mutation, who constitute the bridge between the patients in Europe and in North America. Two novel families with that mutation have recently been identified in Madrid. ‘In cases of sudden cardiac death in the family, people should sit up and take notice,’ says Prof Milting. ‘The families that are known to us have lost several male family members within a short space of time, even though they were under medical observation. Women frequently suffer from cardiac arrhythmias.’ Suspected cases must be looked into, warns the molecular biologist, because people carrying that mutation will definitely get the disease. Sudden cardiac death may be prevented if a defibrillator is implanted in good time.
Genetic analyses are increasingly gaining in importance in healthcare settings as prevention and diagnostic tools. ‘Nevertheless, healthcare professionals are called upon to exercise great discretion when deciding which analyses must necessarily be conducted for which patients,’ stresses Hendrik Milting. ‘After all, the objective is not to stigmatise the affected families, but to prevent severe heart diseases or even sudden cardiac death.’ A team of molecular biologists, cardiologists and human geneticists is in charge of this task at the Heart and Diabetes Center NRW.
The acronym ARVC stands for arrhythmogenic right ventricular cardiomyopathy. A considerable number of patients, most of them men, suffer sudden cardiac death without having ever shown any signs of a cardiovascular disease. The average life expectancy of men who have the ARVC5 genetic mutation is about 41 years. Ruhr University Bochum

An international team of researchers, led by Beaumont Health System’s Jan Akervall, M.D., Ph.D., looked at biomarkers to determine the effectiveness of radiation treatments for patients with squamous cell cancer of the head and neck. They identified two markers that were good at predicting a patient’s resistance to radiation therapy.
Explains Dr. Akervall, co-director, Head and Neck Cancer Multidisciplinary Clinic, Beaumont Hospital, Royal Oak, and clinical director of Beaumont’s BioBank, ‘Radiation therapy is a common treatment for people with squamous cell cancer of the head and neck. However, it’s not always well-tolerated. It can take two months, resulting in lots of side effects. Some of these complications are permanent. Before my patient goes down that path, I really want to know if their tumours are going to respond to radiation. That’s where the patient’s biomarkers can shed some light. If not, we can look at other treatment options – saving time, possible risk for complications and expense.’

A biomarker is a gene or a set of genes or its products, RNA and proteins, that researchers use to predict a key clinical issue such as diagnosis, prognosis, and response to treatment, choice of treatment or recurrence. Biomarker studies can provide a bridge between emerging molecular information and clinical treatment. Biomarkers may also lead to personalised treatment, in contrast to protocol-based medicine of today.

‘Personalised treatment decisions based on biomarkers go beyond traditional cancer staging classifications. Individualised treatment plans could reduce morbidity and potentially improve survival by avoiding treatment failures,’ says Dr. Akervall. ‘There is reason to believe that a better understanding of the biological properties of these tumours, as measured in the patient’s pre-treatment biopsies, may lead us to predict the response to radiation therapy and concurrent chemoradiation, thus allowing for tailored patient-specific treatment strategies.’

The study followed two groups of patients. In the first group, researchers screened 18,000 genes and identified five distinct markers. The second group was larger and confirmed these findings and two of them in particular. Two markers were good at predicting whether or not radiation-based therapy would be effective.

Adds Dr. Akervall, ‘While our findings are encouraging, and a step toward personalised medicine, we hope to do more of this research with a larger, randomised trial.’ Beaumont Research Institute

Massachusetts General Hospital (MGH) investigators have used a new sequencing method to identify a group of genes used by the brain’s immune cells – called microglia – to sense pathogenic organisms, toxins or damaged cells that require their response. Identifying these genes should lead to better understanding of the role of microglia both in normal brains and in neurodegenerative disorders and may lead to new ways to protect against the damage caused by conditions like Alzheimer’s and Parkinson’s diseases. The study also finds that the activity of microglia appears to become more protective with ageing, as opposed to increasingly toxic, which some previous studies had suggested.
‘We’ve been able to define, for the first time, a set of genes microglia use to sense their environment, which we are calling the microglial sensome,’ says Joseph El Khoury, MD, of the MGH Center for Immunology and Inflammatory Diseases and Division of Infectious Diseases, senior author of the study. ‘Identifying these genes will allow us to specifically target them in diseases of the central nervous system by developing ways to upregulate or downregulate their expression.’
A type of macrophage, microglia are known to constantly survey their environment in order to sense the presence of infection, inflammation, and injured or dying cells. Depending on the situation they encounter, microglia may react in a protective manner – engulfing pathogenic organisms, toxins or damaged cells – or release toxic substances that directly destroy microbes or infected brain cells. Since this neurotoxic response can also damage healthy cells, keeping it under control is essential, and excess neurotoxicity is known to contribute to the damage caused by several neurodegenerative disorders.
El Khoury’s team set out to define the transcriptome – the complete set of RNA molecules transcribed by a cell – of the microglia of healthy, adult mice and compared that expression profile to those of macrophages from peripheral tissues of the same animals and of whole brain tissue. Using a technique called direct RNA sequencing, which is more accurate than previous methods, they identified a set of genes uniquely expressed in the microglia and measured their expression levels, the first time such a gene expression ‘snapshot’ has been produced for any mammalian brain cell, the authors note.
Since ageing is known to alter gene expression throughout the brain, the researchers then compared the sensome of young adult mice to that of aged mice. They found that – contrary to what previous studies had suggested – the expression of genes involved in potentially neurotoxic actions, such as destroying neurons, was down-regulated as animals aged, while the expression of neuroprotective genes involved in sensing and removing pathogens was increased. El Khoury notes that the earlier studies suggesting increased neurotoxicity with ageing did not look at the cells’ full expression profile and often were done in cultured cells, not in living animals.
‘Establishing the sensome of microglia allows us to clearly understand how they interact with and respond to their environment under normal conditions,’ he explains. ‘The next step is to see what happens under pathologic conditions. We know that microglia become more neurotoxic as Alzheimer’s disease and other neurodegenerative disorders progress, and recent studies have identified two of the microglial sensome genes as contributing to Alzheimer’s risk. Our next steps should be defining the sensome of microglia and other brain cells in humans, identifying how the sensome changes in central nervous system disorders, and eventually finding ways to safely manipulate the sensome pharmacologically.’ Massachusetts General Hospital

The once sketchy landscape of the molecular defects behind bladder cancer now resembles a road map to new, targeted treatments thanks to the unified efforts of scientists and physicians at 40 institutions.
Deep molecular analysis of 131 muscle-invasive bladder cancer tumours found recurring defects in 32 genes for the cancer that currently has no targeted therapies.
‘By dramatically increasing our knowledge of the molecular basis of bladder cancers, this project casts a spotlight on particular molecules and biological pathways that may serve as targets for a more individualised approach to therapy,’ said project co-chair, lead and senior author John Weinstein, M.D., Ph.D., professor and chair of the Department of Bioinformatics and Computational Biology at The University of Texas M.D. Anderson Cancer Center in Houston.
‘While many of these genomic alterations have been tied to other cancers, nine of these genes have never been reported as significantly mutated in any other type of malignancy,’ Weinstein said. ‘These findings mark additional progress away from defining cancer by organ site and toward molecular classification that spans tumour types.’
Basis for investigating novel therapies and new uses of existing drugs
The most common bladder cancer, urothelial carcinoma, will kill an estimated 15,000 Americans in 2014, with 10 times as many deaths worldwide. Muscle-invasive disease is the most lethal form. Current treatment includes surgery, cisplatin-based multi-agent chemotherapy and radiation.
‘These TCGA data provide a perfect storm for advancing treatment for muscle invasive and hard-to-treat cancer,’ said project co-leader and co-senior author Seth P. Lerner, M.D., professor and chair of Urologic Oncology and Bladder Cancer program leader at Baylor College of Medicine in Houston.
‘We found potential therapeutic targets in 69 percent of tumours and identified bladder cancer subtypes based on gene mutation and expression data,’ Lerner said. ‘One subtype looks similar to squamous cell cancer of the head, neck and lung and basal-like breast cancer. Another subtype looks similar to luminal A breast cancer. These genomic similarities create a logical path to test targeted therapies from these other subtypes of cancer rather than treating bladder cancers as one disease.’
Lerner said long-term planning for clinical trials based on the TCGA data has begun in earnest and will continue this week during the 2014 Genitourinary Cancers Symposium in San Francisco.
Researchers analysed tumours for genetic mutations, gene copy number (deletions and amplifications), gene expression of messenger RNA, microRNA and protein expression, among other factors.
Two biological pathways provided the most common therapeutic targets, including molecules addressed by drugs in clinical trials or approved for other types of cancer.
45 percent of tumours had targets in the growth-factor-signalling receptor tyrosine kinase/MAPK pathway, including HER2 – best known as a drug target in about one third of breast cancers – in 15 percent of tumours, EGFR in 9 percent and FGFR3 in 17 percent.
42 percent had targets in the PI3K/AKT/mTOR pathway, including PIK3CA, which occurred in 17 percent of tumours, TSC1 or TSC2 in 9 percent and AKT3 in 10 percent of tumours. PI3K inhibitors are under development and mTOR inhibitors have been approved for select cancers.
A striking new finding, Weinstein said, was of frequent alterations in genes involved with the regulation of chromatin, the combination of DNA and histone proteins that makes up chromosomes.
Chromatin remodelling greatly influences gene expression and the team found alterations in this pathway in 89 percent of tumours, more than in any other type of cancer analysed to date. This makes bladder cancer a prime candidate for a new class of drugs under development, the authors noted.
Viral DNA was found in 6 percent of tumours, suggesting that viral infection might play a role in the development of a small percentage of bladder cancers. M D Anderson Cancer Center