In addition, the study provides evidence that drugs under development for diseases such as cancer could potentially be used to treat RA. Rheumatoid arthritis, a systemic inflammatory autoimmune disease that can be crippling, impacts over a million adults in the United States.
"We uncovered a novel mechanism by which the Notch pathway could contribute to RA, said Xiaoyu Hu, M.D., Ph.D., a research scientist at Hospital for Special Surgery in New York City and principal investigator of the study. The study appears online in advance of print in Nature Immunology.
Prior to this study, researchers knew that an intracellular molecular pathway called Notch is involved in diseases such as cancer. In the last year, other scientists conducted a genome wide association study to identify genes that were linked to the development of rheumatoid arthritis. They discovered that a certain mutation in a gene involved in the Notch pathway puts patients at risk for RA, but nobody knew just how it was involved.
"We were intrigued. Nothing has been known about how the Notch pathway is important to RA," said Dr. Hu. Working with researchers at other institutions in the United States and abroad, HSS investigators started putting two and two together and noted that Notch might be involved in a misfiring of the immune system that is commonly seen in RA.
The researchers designed experiments to test whether the Notch pathway had an influence on macrophages, a type of white blood cell that is most commonly known for gobbling up pathogens but which can also cause inflammation. Macrophages that have gone awry possess widespread pro-inflammatory and destructive capabilities that can critically contribute to acute and chronic rheumatoid arthritis. "In the case of RA, inflammatory macrophages attack joints and they produce inflammatory mediators that basically sustain inflammation in joints," said Dr. Hu.
In experiments, researchers found that knockout mice that lack the Notch pathway in macrophages were unable to produce certain type of macrophages and exhibited a lesser inflammatory phenotype.
"Notch is essential for the development and function of a cell type called the inflammatory macrophages and if this pathway is missing in mice, then you don't get good differentiation of the inflammatory macrophages," said Dr. Hu. In a nutshell, the Notch pathway is essential for the differentiation and function of inflammatory macrophages, and these macrophages are critical for human RA pathogenesis.
In a series of test tube studies, the researchers flushed out the specifics of how Notch influences the molecular cascade that leads to generation of inflammatory macrophage. In another experiment, the investigators used an inhibitor of the Notch pathway called GSI-34 that is under development and showed that this drug could inhibit the function of macrophages.
The researchers say the study provides the first explanation of how Notch contributes to rheumatoid arthritis pathogenesis. It also shows, for the first time, that investigational Notch inhibitors under development for cancer and Alzheimer's could potentially be used to treat RA. Several Notch inhibitors are under development by various companies and a few are currently in Phase III trials.
"Before this study, the Notch pathway has been implicated mainly in cancer, but in this study we define how it is connected to RA," said Dr. Hu.
The study was supported by funding from the National Institutes of Health and the American College of Rheumatology. Other authors involved in the study include Hospital for Special Surgery researchers Baohong Zao, Ph.D., Lionel Ivashkiv, M.D., Carl Blobel, M.D., Ph.D., Jimmy Zhu, Sinead Smith, and Allen Chung; Julia Foldi, Ph.D., and Chao Shi, Ph.D., from Weill Cornell Graduate School of Medical Sciences; Hasina Outtz and Jan Kitajewski, Ph.D., from Columbia University; Silvio Weber and Paul Saftig, Ph.D., from the Christian Albrechts Universitat Kiel, Kiel, Germany; Yueming Li, Ph.D., from Memorial Sloan-Kettering Cancer Center; and Keiko Ozato, Ph.D., from the National Institute of Child Health and Human Development.
About Hospital for Special Surgery
Founded in 1863, Hospital for Special Surgery (HSS) is a world leader in orthopedics, rheumatology and rehabilitation. HSS is nationally ranked No. 1 in orthopedics, No. 2 in rheumatology, No. 19 in neurology, and No. 16 in geriatrics by U.S.News & World Report (2011-12), and is the first hospital in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center three consecutive times. HSS has one of the lowest infection rates in the country. From 2007 to 2011, HSS has been a recipient of the HealthGrades Joint Replacement Excellence Award. HSS is a member of the NewYork-Presbyterian Healthcare System and an affiliate of Weill Cornell Medical College and as such all Hospital for Special Surgery medical staff are faculty of Weill Cornell. The hospital's research division is internationally recognized as a leader in the investigation of musculoskeletal and autoimmune diseases. Hospital for Special Surgery is located in New York City and online at www.hss.edu.For more information contact:
Phyllis Fisher | EurekAlert!
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine