Columbia University Medical Center (CUMC) scientists have identified new genetic mutations that can cause pulmonary arterial hypertension (PAH), a rare fatal disease characterized by high blood pressure in the lungs.
This is a cross section of a potassium channel in a smooth muscle cell of the pulmonary artery. A study by Dr. Wendy Chung has identified six new mutations in a gene called KCNK3 that can interfere with the function of potassium channels and lead to pulmonary hypertension. The mutations are depicted in color at the locations where they exert their effects.
Credit: Columbia University Medical Center
The mutations, found in the gene KCNK3, appear to affect potassium channels in the pulmonary artery, a mechanism not previously linked to the condition. Cell culture studies showed that the mutations' effects could be reversed with a drug compound known as a phospholipase inhibitor. The study was published today in the online edition of the New England Journal of Medicine.
"The most exciting thing about our study is not that we've identified a new gene involved in pulmonary hypertension, but that we've found a drug that can 'rescue' some mutations," said co-senior author Wendy K. Chung, MD, PhD, associate professor of pediatrics and medicine at CUMC. "In genetics, it's common to identify a gene that is the source of a disease. However, it's relatively rare to find potential treatments for genetic diseases."
PAH is a progressive disorder characterized by abnormally high blood pressure in the pulmonary artery, which reduces blood flow from the right side of the heart to the lungs. The heart can compensate by pumping harder, but over time this can weaken the heart muscle and lead to right-sided heart failure. Common symptoms of PAH include shortness of breath, dizziness, and fainting. About 1,000 new cases are diagnosed in the United States each year. The disorder is twice as common in females as in males. There is no cure for PAH and few effective treatments. Most patients with PAH die within 5–7 years of diagnosis.
Some cases of PAH are caused by inherited genetic defects. Most of these "familial" cases have been linked to mutations in a gene called BMPR2 (bone morphogenetic protein receptor, type II), which was identified simultaneously in 2000 by two independent research teams, one led by the late Robin Barst and Jane Morse, CUMC researchers. However, the majority of cases are idiopathic in origin (of unknown cause). Other forms of PAH can be triggered by autoimmune diseases, congenital heart defects, infections (such as schistosomiasis), and medications (such as the now-banned diet-drug combination commonly known as fen-Phen).
Dr. Chung and her colleagues discovered the new mutations by sequencing the exomes (the portion of the genome that codes information to make proteins) of families with PAH without identified mutations. KCNK3 mutations were found in 3.2 percent of those with familial disease and in 1.3 percent of those with idiopathic PAH.
The team found that the mutations alter the function of potassium channels by reducing the activity of these channels. Potassium channels help maintain the vascular tone of the pulmonary artery and help it respond to low levels of oxygen.
"We were surprised to learn that KCNK3 appears to play a role in the function of potassium channels in the pulmonary artery," said Dr. Chung. "No one had suspected that this mechanism might be associated with PAH." The other gene linked to the disorder, BMPR2, is thought to cause PAH by ultimately promoting growth and multiplication of smooth muscle cells in the pulmonary artery, thereby restricting blood flow.
Dr. Chung also found, working in collaboration with co-senior author, Robert S. Kass, PhD, the Alumni and David Hosack Professor of Pharmacology, chair of the department, and vice dean for research at CUMC, that the effects of the KCNK3 mutations could be reversed with an experimental phospholipase inhibitor called ONO-RS-082. The findings were made in cell cultures. Further study is needed to determine whether treatment with this or other drugs that affect potassium channels might be useful in the treatment of people with PAH, said Dr. Chung.
"KCNK3 mutations are a rare cause of PAH, so I don't want to oversell our findings," said Dr. Chung. "Still, it's exciting that we've found a mechanism that can lead to the disease that is a new, druggable target. It's also possible that targeting KCNK3 may be beneficial for patients who have PAH independent of their KCNK3 genetic status."
The paper is titled, "A Novel Channelopathy in Pulmonary Arterial Hypertension." The other contributors are: Lijiang Ma, Danilo Roman-Campos, Eric D, Mélanie Eyries, Kevin Sampson, Florent Soubrier, Marine Germain, David-Alexandre Trégouët, Alain Borczuk, Erika Berman Rosenzweig, Barbara Girerd, David Montani, Marc Humbert, and James E. Loyd.
The authors declare no financial or other conflicts of interests.
The study was supported by grants from the National Institutes of Health (R01 HL060056, P01 HL072058, K23 HL098743, and R01 HL56810) and by a Vanderbilt Clinical and Translational Science Awards (UL1 RR024975) from the National Center for Research Resources.
Columbia University Medical Center provides international leadership in basic, preclinical, and clinical research; medical and health sciences education; and patient care. The medical center trains future leaders and includes the dedicated work of many physicians, scientists, public health professionals, dentists, and nurses at the College of Physicians and Surgeons, the Mailman School of Public Health, the College of Dental Medicine, the School of Nursing, the biomedical departments of the Graduate School of Arts and Sciences, and allied research centers and institutions. Columbia University Medical Center is home to the largest medical research enterprise in New York City and State and one of the largest faculty medical practices in the Northeast. For more information, visit cumc.columbia.edu or columbiadoctors.org.
Karin Eskenazi | EurekAlert!
Transport of molecular motors into cilia
28.03.2017 | Aarhus University
Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy