Variations in genes that regulate immune responses in a region of chromosome 6 have long been linked with susceptibility for many infectious and chronic inflammatory conditions, including ulcerative colitis, said Richard H. Duerr, M.D., professor of medicine, Pitt School of Medicine, co-director and scientific director, UPMC Inflammatory Bowel Disease Center, and the corresponding author of the study. Ulcerative colitis is characterized by recurrent inflammation of the large intestine that results in diarrhea mixed with blood and abdominal pain.
"We tested more than 10,000 points, called single nucleotide polymorphisms, or SNPs, in the gene sequence in this chromosomal region, and we also tested amino acid variations in human leukocyte antigen (HLA) proteins that were deduced from the SNPs to identify those most important for ulcerative colitis," Dr. Duerr said. "Refining the gene association signals in this region enabled us to better understand the underlying mechanisms of the disease."
Using sophisticated association techniques, the authors confirmed that an HLA gene called DRB1, which codes for a protein that is involved in the immune response and routinely tested in tissue matching for organ transplantation, was uniquely related to ulcerative colitis. Variation, or polymorphism, in that gene altered which amino acid was selected for the 11th position in the DRB1 protein – a key location because it is in a pocket of the so-called binding cleft where other proteins, such as antigens or markers of foreign cells, attach.
"This particular position probably plays a significant role in determining the human immune response to extracellular antigens," Dr. Duerr said. "It ties into theories that ulcerative colitis might result from an abnormal immune response to gastrointestinal bacterial antigens or might be an autoimmune disorder caused by an abnormal immune response to a self-antigen."
The researchers also looked for a similar relationship between that amino acid position and Crohn's disease, another chronic inflammatory bowel condition, but did not find a strong association. Still, variants in immune response genes on chromosome 6 likely contribute not only to ulcerative colitis and Crohn's disease, but also to other immune-mediated diseases such as rheumatoid arthritis and multiple sclerosis, added Jean-Paul Achkar, M.D., Department of Gastroenterology & Hepatology, Cleveland Clinic Digestive Disease Institute, an alum of the gastroenterology and hepatology training program at UPMC, and first author of the study.
In addition to Pitt School of Medicine and the Cleveland Clinic, the team included researchers from Pitt Graduate School of Public Health and Children's Hospital of Pittsburgh of UPMC; Harvard Medical School, the Broad Institute of Harvard and the Massachusetts Institute of Technology; the University Medical Center Utrecht, the Netherlands; and Carnegie Mellon University.
The project was funded by National Institutes of Health grants DK068112, AG030653, MH057881, DK062420 and DK076025; a Crohn's & Colitis Foundation of America Senior Research Award; U.S. Department of Defense Grant W81XWH-07-1-0619; and funds generously provided by Kenneth and Jennifer Rainin, Gerald and Nancy Goldberg, and Victor and Ellen Cohn.
About the University of Pittsburgh School of Medicine
As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997.
Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see http://www.medschool.pitt.edu
Anita Srikameswaran | EurekAlert!
Immune Defense Without Collateral Damage
23.01.2017 | Universität Basel
The interactome of infected neural cells reveals new therapeutic targets for Zika
23.01.2017 | D'Or Institute for Research and Education
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
23.01.2017 | Health and Medicine
23.01.2017 | Physics and Astronomy
23.01.2017 | Process Engineering