Showing posts with label enzyme. Show all posts
Showing posts with label enzyme. Show all posts

Monday, 29 July 2013

Enzyme in airway lining cells could hold key for asthma sufferers

Main Category: Respiratory / Asthma
Article Date: 27 Jul 2013 - 0:00 PDT Current ratings for:
Enzyme in airway lining cells could hold key for asthma sufferers
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An enzyme known for its role in heart disease may well be a promising target to treat asthma. Researchers from the University of Iowa have found that the enzyme, called CaMKII, is linked to the harmful effects of oxidation in the respiratory tract, triggering asthmatic symptoms. The finding could lead to the development of a drug that would target the CaMKII enzyme, the researchers say.

Asthma affects billions of people worldwide. In the United States, 8.5 percent of the population has asthma, which causes 3,000 deaths and more than $56 billion annually in medical and lost work costs, according to the federal Centers for Disease Control and Prevention. Despite its toll on health and productivity, treatment options remain confined to steroids, which have harmful, even life-threatening, side effects for those with severe cases.

Current treatments don't work well, noted Mark Anderson, professor and chair in internal medicine at the UI and a co-corresponding author on the paper, published in the journal Science Translational Medicine.

"It's a kind of an epidemic without a clear, therapeutic option," Anderson says. "The take-home message is that inhibiting CaMKII appears to be an effective anti-oxidant strategy for treating allergic asthma."

Anderson and co-corresponding author Isabella Grumbach knew from previous work that the CaMKII enzyme played a role in the oxidation of heart muscle cells, which can lead to heart disease and heart attacks. The scientists surmised the same enzyme may affect oxidation in the respiratory system as well.

The team first tested the enzyme in airway muscle cells, but to little effect. They then tried to block the enzyme in the airway lining (epithelial) cells. They noticed that mice with the blocked enzyme had less oxidized CaMKII, no airway muscle constriction and no asthma symptoms. Similarly, mice without the blocked enzyme showed high "oxidative stress," meaning lots of oxidized enzymes in the epithelial cells, a constricted airway and asthma symptoms.

"[The study] suggests that these airway lining cells are really important for asthma, and they're important because of the oxidative properties of CaMKII," says Anderson, whose primary appointment is in the Carver College of Medicine. "This is completely new and could meet a hunger for new asthma treatments. Here may be a new pathway to treat asthma."

"Ten years ago, not much was known about what CaMKII does outside of nerve cells and muscle cells in the heart," says Grumbach, associate professor in internal medicine at the UI. "My lab has worked on investigating its function mainly in blood vessels with the long-term goal to use blockers of CaMKII to treat common diseases. We are constantly finding that CaMKII is interesting and important."

The researchers also took tissue samples from the airways of patients with asthma. True to their hypothesis, they found more oxidized enzymes in those patients than in healthy individuals. Taking a step further, the team found that mild asthma patients who inhaled an allergen had a spike in oxidized CaMKII in the epithelial cells just a day later.

"We have this very compelling association," Anderson says, adding that more studies in patients are needed to validate the approach.

The researchers also plan to investigate inhaled drugs that could block the oxidation of theCaMKII enzyme, for treating heart disease and asthma. Anderson has a patent and is involved in a company, Allosteros Therapeutics, which is seeking to develop such a drug.

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our respiratory / asthma section for the latest news on this subject.

The paper’s first author is Philip Sanders, a former postdoctoral student in Grumbach's lab, helped design the study and analyzed much of the data. Contributing authors from the UI include Olha Koval, Omar Jaffer, Anand Prasad, Thomas Businga, Jason Scott, Elizabeth Luczak, David Dickey, Francis Miller, Jr., Megan Dibbern, Joseph Zabner, Joel Kline, Chantal Allamargot, Alicia Olivier, David Meyerholz, Brett Wagner, Garry Buettner and Marshall Pope. Other contributing authors are Patrick Hayden from MatTek Corporation; Alfred Robison from the Mount Sinai School of Medicine in New York; Danny Winder, Timothy Blackwell and Ryszard Dworski from Vanderbilt University; Hans Michael Haitchi, David Sammut and Peter Howarth from the University of Southampton, United Kingdom; and Peter Mohler from Ohio State University.

The National Institutes of Health (grant numbers: K23 HL080030 02 and M01 RR-00095), the American Asthma Foundation and the Sandler Program for Asthma Research funded the work.

University of Iowa

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Friday, 26 July 2013

High levels of a specific enzyme in mice fetuses linked to anxiety

Main Category: Anxiety / Stress
Also Included In: Depression;  Neurology / Neuroscience
Article Date: 25 Jul 2013 - 2:00 PDT Current ratings for:
High levels of a specific enzyme in mice fetuses linked to anxiety
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Mouse embryos with the human enzyme CYP2C19 in the brain develop a smaller hippocampus and anxiety-like behaviour as adults. The results of this new study, which is published in the journal Molecular Psychiatry, agree in principle with earlier genetic findings in humans, and can improve science's understanding of the genetic factors behind depression and anxiety disorders and contribute to the development of new anti-anxiety drugs.

Scientists have long been searching for the genetic reasons for the great differences in sensitivity that people show towards depression and anxiety disorders. Now, researchers at Karolinska Institutet in Sweden have taken a closer look at the CYP2C19 enzyme, which plays an important part in the liver metabolism of psychoactive substances, such as antidepressants (e.g. SSRI drugs). CYP2C19 also operates on endogenous substances that affect the central nervous system. Interestingly, there is a genetic variation between humans, since mutations of the CYP2C19 gene leave people with no, low, normal or high levels of the enzyme.

The present study was conducted on transgenic mice, which had copies of the human CYP2C19 gene inserted into their DNA so that the researchers could examine if the expression of CYP2C19 affected brain function and behaviour. It was discovered that the enzyme was found in the brain of the mouse fetus, which developed differently to that of normal mice. The behaviour of the mice was then examined using a battery of four behavioural tests.

"We found behavioural changes indicating anxiety and a higher stress sensitivity," says research group leader Magnus Ingelman-Sundberg from the Department of Physiology and Pharmacology. "These findings can tell us more about the genetic determinants of anxiety and the transgenic mice can hopefully be used to develop new anxiolytic drugs."

The expression of CYP2C19 in the fetus produced adult mice that had a smaller, stress-hypersensitive hippocampus, an area of the brain essential to learning and memory, adaption and sensitivity to stress and emotional response. A dysfunctional hippocampus in humans is thought to play an important part in the development of both depression and anxiety disorders.

In an earlier study on twins conducted with epidemiologists from Karolinska Institutet, the group observed that individuals lacking the CYP2C19 enzyme display a less depressed base state, a finding that is supported in principle by the present study on mice. The researchers now plan to study what effects genetic variations of CYP2C19 have on the development of the human brain.

"If we can see similar changes in humans, it would improve our understanding of how changes in the developing fetal brain can increase the risk of depression and anxiety disorders later in life," says Anna Persson, in whose doctoral project the study is included.

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our anxiety / stress section for the latest news on this subject.

The study was financed by grants from the Swedish Brain Fund, the Torsten and Ragnar Söderberg Foundations, the Swedish Research Council and the Swedish Governmental Agency for Innovation Systems (Vinnova).

“Decreased hippocampal volume and increased anxiety in a transgenic mouse model expressing the human CYP2C19 gene”, Anna Persson, Sarah C Sim, Susanne Virding1, Natalia Onishchenko, Gunnar Schulte1, Magnus Ingelman-Sundberg, Molecular Psychiatry, online 23 2013.

Karolinska Institutet

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'High levels of a specific enzyme in mice fetuses linked to anxiety'

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View the original article here