Tag: cystic fibrosis

Categories : Diseases, Syndromes and ConditionsTags :

Oil Exploration Software Reveals why Cystic Fibrosis Drugs Fail

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Scientists have harnessed a computational approach usually used in oil exploration to search for cures for rare genetic diseases such cystic fibrosis. By using the method to analyse the spatial relationships between different variants of a protein, instead of the relationships between test wells across an oil field, the researchers can obtain valuable information on how disease affects a protein’s underlying shape and how drugs can restore that shape to normal.

The new method, detailed in the journal Structure, runs with just a few gene sequences collected from people with disease. Then, it determines how the structure of each corresponding variant protein is associated with its function, and how this functional structure can affect pathology and be repaired by therapeutics. To test the techniques, the researchers showed why existing drugs for cystic fibrosis fall short of curing the disease.

“This is an important step forward for treating rare diseases,” said senior author William Balch, PhD, professor of Molecular Medicine at Scripps Research. “The fact that we can get so much information from a few gene sequences is really unprecedented.”

Studies on inherited diseases often rely on the precise three-dimensional shape of a protein affected by disease. But genetic diseases can be caused by thousands of gene variants, some of which destabilise or change the protein shape in ways that make isolating the protein for further investigation much more difficult than usual.

Prof Balch, with Scripps Research senior staff scientist Chao Wang and staff scientist Frédéric Anglés, instead wanted to use natural variation to their advantage. So the group developed a method called variation-capture (VarC) mapping to analyse the natural array of gene sequences which exist in the human population and determine the mechanism by which they each changed a protein’s structure to cause disease.

Among other statistical tools, Prof Balch’s group integrated the methods that oil companies use to draw inferences about the location of an oil reservoir using only a small number of test wells. With only a few gene sequences, this let the researchers determine the most likely structural mechanisms driving function for each variant leading to disease, as well as model how drugs impacted those structural functions.

In the case of cystic fibrosis, disease is caused by genetic variants in the cystic fibrosis transmembrane conductance regulator (CFTR), leading to a buildup of mucus in the lungs. More than 2000 variants of the CFTR gene have been identified, and many of these variants were known to have very different effects on the CFTR protein, but it has been difficult to compare and contrast these variants to guide how patients with different variants should be treated differently in the clinic.

“When you want to treat patients, you really have to appreciate that different therapeutics might target different variants in completely different ways, and that’s why our approach that looks at many different variants all at once is so powerful,” explained Wang. “Our approach not only reveals how these variants contribute to each patient’s biology, but also connects them in a way that each variant can inform how to manage the others.”

The researchers input about 60 genetic variants found in the cystic fibrosis population into their VarC program. The analysis captured how each amino acid residue talks to every other residue to generate function, and revealed that most of the cystic fibrosis patients had the same net effect on the protein: an unstable inner core.

When the program modelled how existing cystic fibrosis drugs impacted the structures, the researchers discovered that, despite the drugs’ effect on CFTR structure, none of them effectively stabilised the protein’s hidden inner core. This was like how the location of an oil reservoir in a complex landscape can be revealed by test wells.

Now that the researchers better understand the structural deficiencies in CFTR in cystic fibrosis patients, they say that the job of developing an effective drug to fix it is much easier. Potential compounds can be modelled in advance of lab experiments for their effect on the inner core of the CFTR protein.

“In most drug discovery, you throw thousands of compounds at a protein and see which ones change it, often without fully understanding the mechanism,” said Prof Balch. “To fix a thing, you must first understand the problem.”

Already, his team is applying the method to other rare genetic diseases, as well as pursuing new drugs to treat cystic fibrosis.

Source: Scripps Research Institute

Categories : Respiratory DiseasesTags :

Mucus Hydration Approach Could Help Treat Cystic Fibrosis

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Anatomical model of lungs
Photo by Robina Weermeijer on Unsplash

Using a model reproducing a respiratory epithelium, researchers have discovered that a simple film of liquid is sufficient to restore the airways’ seal and reduce the risk of bacterial infection. Their findings, published in the journal Cells, may enable new therapies based on mucus hydration – a promising alternative to current therapies which often lack efficacy.

Despite recent therapeutic advances, people with cystic fibrosis (one in every 2500 births in Europe) have a life expectancy of no more than 46 years and altered quality of life. The disease is caused by one or more mutations in the CFTR gene, which affects the proper functioning of an essential protective barrier. The epithelial cells that line the airways are usually sealed together and thus protect the airways from bacterial colonisation. They are also lined with a fluid, a slippery mucus that traps unwanted germs and carries them away. When the CFTR protein is altered, the junctions between the cells loosen and the dehydrated mucus tends to stagnate, both of which promote the development of respiratory infections.

“While it was already known that mucus hydration and the presence of sufficiently tight junctions preserved the integrity of the airways, the mechanisms involved and the links between these two mechanisms remained mysterious, which hindered the development of new therapies,” explained Professor Marc Chanson, who led the reasearch.

Hydrating to restore tightness

The scientists first developed an in vitro model using human lung cells. This model reproduces airways epithelium of healthy and cystic fibrosis patients in a way that is both accurate and close to clinical reality. The researchers compared the response of epithelial cells invalidated for CFTR to bacterial infection, to which either hydrated, healthy mucus or physiological saline solution had been added.

“We observed a similar response in both cases: the presence of liquid, whatever its composition, restored the airways and protected them from infection,” explained Juliette Simonin, post-doctoral fellow in Prof Chanson’s laboratory and first author of the study. “Surface hydration is sufficient to tighten the junctions between cells and protects the epithelium integrity from bacterial colonisation, even when CFTR is not functioning.”

One treatment for all mutations?

A triple therapy pharmacologically targeting the CFTR protein has recently become available on the market. However, it only targets certain mutations of the CFTR gene and is only prescribed for a specific population of people with cystic fibrosis. More widely effective and safe treatments are still sorely lacking.

“Our results provide evidence that rehydration of the airway surface is beneficial. The challenge now is to find a simple way of doing this in all people with the disease, whatever the mutation involved,” concluded Prof Chanson.

Source: Université de Genève

Categories : Respiratory DiseasesTags :

Distinct Lower Airways Bacterial Profile inChildren with Cystic Fibrosis

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Phot by Ben Wicks on Unsplash

In children with cystic fibrosis (CF), their lower airways have a higher burden of infection, more inflammation and lower diversity of microorganisms, compared to children with other illnesses who also have lung issues, researchers have found. They noted a clear divergence in these bacterial communities in toddlers, before progressive lung disease manifests in CF patients. 

Their findings, published in the journal PLOS ONE, could help providers target specific pathogens earlier, treat them and potentially prevent more severe lung disease.

As lead author Jack O’Connor, at Ann & Robert H. Lurie Children’s Hospital of Chicago explained, “We compared lower airway samples from bronchoscopy in children with CF and disease controls across the age spectrum, and used genetic sequencing to identify microorganisms, finding that a few common cystic fibrosis pathogens begin to dominate at very early ages. Such a clear split from disease controls in this young age group has not been shown before. Our findings deepen our understanding of the disease trajectory in cystic fibrosis and could help improve outcomes through earlier intervention.”

Chronic airway infection and inflammation which leads to progressive, obstructive lung disease is the main cause of illness and death in people with cystic fibrosis.

Researchers tested lower airway samples from 191 patients (63 with cystic fibrosis) aged 0-21 years. The disease controls included patients with diverse conditions, such as cancer, immune deficiency and pneumonia. Using genetic sequencing, researchers were able to identify distinct pathogens that are more dominant at different ages in patients with cystic fibrosis.

“Establishing key age-related differences in lower airway bacterial communities and inflammation in patients with CF, especially during early childhood, may give us a window of opportunity for earlier and more precise treatment,” said senior author Theresa Laguna, MD, MSCS, Division Head of Pulmonary and Sleep Medicine at Lurie Children’s and Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine. “If we can prevent worse infections, we could improve the quality of life and potentially expand the life expectancy of patients with CF.”

Source: News-Medical.Net

Categories : General InterestTags :

‘Absolutely Revolutionary’ Kaftrio Drug Betters Lives of Cystic Fibrosis Patients

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In an article by the BBC, one woman with cystic fibrosis recounts how the “absolute revolutionary” Kaftrio drug has improved her life.

Jody Lewis, 31, is an avid rider and one of around 80 people in Wales to have had Kaftrio, a “revolutionary” drug treatment for cystic fibrosis, at Liverpool Heart and Chest Hospital.

Cystic fibrosis is a genetic condition resulting in faulty cystic fibrosis transmembrane conductance regulator (CFTR) proteins which regulate the transfer of chloride ions into and out of the cells. The condition causes thick, sticky mucus to build up in the lungs, gastrointentinal system and other organs.

The treatment is suitable for around 90% of CF patients aged 12 and over and has been approved for use in the UK. Kaftrio is a triple combination of elexacaftor, tezacaftor which corrects the faulty CFTR protein, and  ivacaftor, which potentiates CFTR. 

Ms Lewis, said since taking it she had “a whole future and life” ahead of her.
Her condition worsened about two and a half years ago, when she was put on continuous oxygen supply, needing four or five oxygen bottles a day, almost placed on a ventilator and considered for a lung transplant. This meant stopping riding and changing how she cared for her four dogs.

“I’d have to change my complete lifestyle just to survive. I get that I’d have a second chance at life but it wouldn’t be me, it wouldn’t be true to who I am,” she said. At her worst, she said she could barely cope with simple tasks such as making tea.

This all changed when she started taking Kaftrio last year.

“Within a week, my [oxygen saturation] was going up and up to 94, 96 and I wasn’t even on oxygen and I can’t remember the last time I saw those numbers, it was mad.

“I’m now as good as I was back when I was 25, so I’ve like regained six years of my life,” she said.

“When I was 25 I was fine, I was in work, living a normal life, so it’s given me all that back really,” she said, adding that it was “really emotional” and “fantastic” to be able to ride her horse again after two and a half years..

“I’ve got a whole future and life in front of me that I’ve never had to think about.”

Consultant Martin Ledson, clinical lead for respiratory medicine at Liverpool Heart and Chest Hospital, described the drug treatment as “absolutely revolutionary”, saying that it had changed the lives of 222 of the hospital’s patients.

He said that when his patients were born, they could expect to live to their 30s, so they have “lived all their lives with the knowledge that their life expectation could be 30 or even less”.

“What this drug does is extend that life expectancy who knows how long?

“Not only that, the patients immediately – within 24 hours – feel amazingly better. Their breathing tests improve, they get less chest infections, their digestion improves, they put on weight and in many cases need to take less treatment,” he said.

Source: BBC News

Categories : Diseases, Syndromes and ConditionsTags :

Bacteria in Cystic Fibrosis Use Slimy Shield to Ward off Drugs

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Research has revealed that a common bacteria found in the lungs of those with cystic fibrosis produces a slime that acts as a defence against a variety of therapeutic drugs.

Dr Laura Jennings, a research assistant professor in UM’s Division of Biological Sciences and an affiliate with the University’s Center for Translational Medicine, headed the research.

A life threatening-condition caused by a genetic mutation, cystic fibrosis causes persistent lung infections and gradually reduces a person’s breathing capacity. A common strain of bacteria, Pseudomonas aeruginosa, often thrives in the lungs of people with cystic fibrosis,  and when a P. aeruginosa infection is established, it can be extremely hard to remove.
The research showed that stubborn bacteria dwelling in the lungs of cystic fibrosis patients produce a carbohydrate slime, which both shields them against antibiotics and also mucus-reducing drugs.

“We found the first direct evidence that these carbohydrates are produced at the sites of infection,” Dr Jennings said. “We showed that one of the carbohydrates, called Pel, sticks to extracellular DNA, which is abundant in the thick mucus secretions prominent in cystic fibrosis lungs.

“This interaction makes a slimy protective layer around the bacteria, making them harder to kill,” she said. “As such, it reduces the pathogen’s susceptibility to antibiotics and drugs aimed at reducing the thickness of airway mucus by digesting DNA.”

She explained that the research supports a theory that these carbohydrates also support the aggregation of these bacteria in the lungs of cystic fibrosis patients.

“This is important because we know that physically breaking up bacterial aggregates can restore bacterial susceptibility to killing with antibiotics and cells of the immune system,” Jennings said. “Therefore, understanding the mechanisms that promote bacterial aggregation may facilitate new therapeutic approaches aimed at digesting the carbohydrates holding bacterial cells together.”

Source: Medical Xpress

Journal information: Laura K. Jennings et al. Pseudomonas aeruginosa aggregates in cystic fibrosis sputum produce exopolysaccharides that likely impede current therapies, Cell Reports (2021). DOI: 10.1016/j.celrep.2021.108782