nandixon
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Has this already been posted somewhere?:
NIH researchers reveal link between powerful gene regulatory elements and autoimmune diseases
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NIH researchers reveal link between powerful gene regulatory elements and autoimmune diseases
Bethesda, Md., Tues., Feb. 17, 2015 - Investigators with the National Institutes of Health (NIH) have discovered the genomic switches of a blood cell are key to regulating the human immune system. The findings, published in Nature today [reference], open the door to new research and development in drugs and personalized medicine to help those with autoimmune disorders such as inflammatory bowel disease or rheumatoid arthritis.
Identifying autoimmune disease susceptibility genes can be a challenge because in most cases a complex mix of genetic and environmental factors is involved. Genetic studies have shown that people with autoimmune diseases possess unique genetic variants, but most of the alterations are found in regions of the DNA that do not carry genes. Scientists have suspected that the variants are in DNA elements called enhancers, which act like switches to control gene activities.
Dr. O'Shea's team wondered if the alterations might lie in a newly discovered type of enhancer called a super-enhancer (SE). Earlier work in the laboratory of Dr. Collins and others had shown that SEs are especially powerful switches, and that they control genes important for the function and identity of each individual cell type. In addition, a large number of disease-associated genetic alterations were found to fall within SEs, suggesting that disease occurs when these switches malfunction.
Dr. O'Shea's team began by searching for SEs in T cells, immune cells known to play an important role in rheumatoid arthritis. They reasoned that SEs could serve as signposts to steer them toward potential genetic risk factors for the disease.
Using genomic techniques, the researchers combed the T cell genome for regions that are particularly accessible to proteins, a hallmark of DNA segments that carry SEs. They identified several hundred, and further analysis showed that they largely control the activities of genes that encode cytokine and cytokine receptors. These types of molecules are important for T cell function because they enable them to communicate with other cells and to mount an immune response.
But the researchers' most striking observation was that a large fraction of previously identified alterations associated with rheumatoid arthritis and other autoimmune diseases localized to these T cell SEs...
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