Researchers at the University of Iowa Roy J. and Lucille A. Carver College of Medicine have discovered a specific repair mechanism in heart muscle and identified a protein called dysferlin that is critical for resealing heart muscle cell membranes.
The study, led by UI researcher and Howard Hughes Medical Institute investigator Kevin Campbell, Ph.D., also shows that loss of dysferlin causes cardiomyopathy in mice. Furthermore, heart damage in these mice is exaggerated by vigorous exercise or by inherent muscle weakness caused by a muscular dystrophy defect. The results are published in the July 1 issue of the Journal of Clinical Investigation.
Active tissues, like a beating heart or contracting muscle, need mechanisms to repair the inevitable cell membrane tears caused by physical stress and strain. In 2003, Campbell and his colleagues identified dysferlin as a key protein in this vital repair mechanism in skeletal muscle. In humans, dysferlin deficiency -- which leads to faulty muscle membrane repair -- causes three types of muscular dystrophy.
The new study expands knowledge of dysferlin function, showing that dysferlin-mediated membrane repair is also important in heart muscle cells and suggests that inadequate membrane repair can also lead to cardiomyopathy.
"If we could boost this repair mechanism, it might be possible to slow cardiac and skeletal muscle damage in muscular dystrophy patients," said Campbell who also holds the Roy J. Carver Biomedical Research Chair in Molecular Physiology and is head of the department and a UI professor of neurology.
The UI team initially found that young mice that lacked dysferlin showed no heart damage, which is consistent with what is seen in humans with dysferlin mutations. However, a case study describing late-onset cardiomyopathy in a Japanese patient with a dysferlin deficiency prompted the UI team to look at the mice as they aged.
They found that the mice started to develop cardiomyopathy at about one year of age (middle aged for a mouse). The team also found that exercise exaggerated the stress-induced injury in these mice, suggesting that inadequate membrane repair led to cardiomyopathy.
The research team also bred mice that lacked both dysferlin and the protein dystrophin, which is missing in patients with Duchenne muscular dystrophy. These "double knockout" mice had early onset cardiomyopathy, which was much more severe than in mice with either of the single mutations. The results suggest that dysferlin might provide some protection against heart damage in Duchenne patients, at least at a young age, by delaying the onset of cardiomyopathy.
"We hope these findings will stimulate clinicians to look at the cardiac health of muscular dystrophy patients and the overall muscle health of patients with cardiomyopathy," Campbell said.
Jennifer Brown | EurekAlert!
Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University
How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy