Research links genetic mutations to lupus

A gene discovered by scientists at Wake Forest University School of Medicine has been linked to lupus and related autoimmune diseases. The finding, reported in the current issue of Nature Genetics, is the latest in a series of revelations that shed new light on what goes wrong in human cells to cause the diseases.

“This research is a huge leap toward understanding the cause of lupus and related autoimmune diseases,” said Fred Perrino, Ph.D., a co-author on the paper and a professor of biochemistry at Wake Forest. “There had been few clues before now.”

Perrino, who discovered the gene in 1998, said he suspected it was involved in human disease, but it took a group of researchers from around the world collaborating to put the puzzle together.

“We’ve known that lupus was a complex disease, but now we have a specific protein and a particular cellular process that appears to be one of the causes,” said Perrino. “We’re connecting the dots to understand the biology of what’s going on with the disease.”

In Nature Genetics, lead author Min Ae Lee-Kirsch, M.D., from the Technische Universität Dresden in Dresden, Germany, and colleagues report finding variations of the TREX1 gene discovered by Perrino in patients with systemic lupus erythematosus. The study involved 417 lupus patients from the United Kingdom and Germany. Mutations were found in nine patients with lupus and were absent in 1,712 people without lupus.

"Our data identify a stronger risk for developing lupus in patients that carry variants of the gene," said Lee-Kirsch.

In recent years, the gene was also linked to Aicardi-Goutieres syndrome, a rare neurological disease that causes death in infants, and to chilblain lupus, an inherited disease associated with painful bluish-red skin lesions that occur during cold weather and usually improve in summer. The current research also links it to Sjogren’s syndrome, a form of lupus.

The diseases are all autoimmuine diseases, which means that the body makes antibodies against itself. In lupus, these antibodies cause pain and inflammation in various parts of the body, including the skin, joints, heart, lungs, blood, kidneys and brain. The disease is characterized by pain, heat, redness, swelling and loss of function.

Perrino began studying the protein made by the gene more than 14 years ago.

“We basically cracked open cells to locate the protein and find the gene,” said Perrino. “In the 14 years since, we’ve learned a lot about the protein and how it functions.”

The gene manufactures a protein, also known as TREX1, whose function is to “disassemble” or “unravel” DNA, the strand of genetic material that controls processes within cells. The “unraveling” occurs during the natural process of cells dying and being replaced by new cells. If a cell’s DNA isn’t degraded or unraveled during cell death, the body develops antibodies against it.

“If the TREX1 protein isn’t working to disassemble the DNA, you make antibodies to your own DNA and can end up with a disease like lupus,” said Perrino.

Perrino and colleagues at Wake Forest have been studying the gene and its protein since 1993. Thomas Hollis, Ph.D., an assistant professor of biochemistry at Wake Forest, is credited with solving the structure of both TREX1 and a similar protein, TREX2. Perrino has also developed a way to measure the function of the proteins.

In a study reported in April in the Journal of Biological Chemistry, Hollis and Perrino found that three variations of the gene reduced the activity of the protein by four- to 35,000-fold.

“Now that we have the structure, we can understand how it disassembles DNA and how mutations in the gene may affect that process,” said Hollis.

The researchers hope that understanding more about the gene’s mutations and the structure of the protein may lead to drug treatments to help ensure that mutant copies of the gene are inactive.

Source: Wake Forest University Baptist Medical Center

Related stories:

Abnormal 'editing' of gene messages may be a cause of lupus
Researchers at Wake Forest University have uncovered evidence that the abnormal “editing” of gene messages in a type of white blood cell may be behind the development of lupus. Scientists hope the finding will lead to earlier diagnosis, a way to monitor patients’ response to therapy and possibly a new way to treat the disease.
Breakdown of kidney's ability to clean its own filters likely causes disease
The kidney actively cleans its most selective filter to keep it from clogging with blood proteins, scientists from Washington University School of Medicine in St. Louis reveal in a new study. Researchers showed that breakdown of this self-cleaning feature can make kidneys more vulnerable to dysfunction and disease.
Scientists find new genetic mutation that halts the development of lupus
The new study was published in the January 18 edition (Volume 28, Issue 1) of the journal Immunity.
Scientists associate 6 new genetic variants with heart disease risk factor
Using new techniques for rapidly scanning the human genome, researchers have associated levels of cholesterol and triglycerides, two fats in the blood, to 18 genetic variants, six of which represent new DNA regions never before associated with the traits. The findings, appearing in the January 13 advance online issue of Nature Genetics, help explain some of the variability in cholesterol and triglyceride levels that arises from genes.
2 genes are important key to regulating immune response
A research team at Weill Cornell Medical College in New York City has identified two genes that may be crucial to the production of an immune system cytokine called interleukin-10 (IL-10).
Study reveals a key to blood vessel growth and possible drug target
Researchers have identified a molecular pathway that plays a critical role in the growth of blood vessels. The finding not only offers an important insight into the development of the vascular system during embryonic development but suggests a potential target for inhibiting the blood vessels that fuel cancers, diabetic eye complications and atherosclerosis, the researchers say.
Study identifies genetic risk factor for rheumatoid arthritis, lupus
A genetic variation has been identified that increases the risk of two chronic, autoimmune inflammatory diseases: rheumatoid arthritis (RA) and systemic lupus erythematosus (lupus). These research findings result from a long-time collaboration between the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and Skin Diseases and other organizations.
Green tea holds promise as new treatment for inflammatory skin diseases
Green tea could hold promise as a new treatment for skin disorders such as psoriasis and dandruff, Medical College of Georgia researchers say.

News discussion:

Medicine & Health news