RNA can both carry genetic information and catalyze chemical reactions, but it’s too wobbly to accurately read the genetic code by itself. Enzymatic modifications of transfer RNAs – the adaptors that implement the genetic code by connecting messenger RNA to protein – are important to stiffen and constrain their interactions.
Biochemist Christine Dunham’s lab has a recent paper in eLife showing a modification on a proline tRNA prevents the tRNA and mRNA from slipping out Read more
When studying Crohn’s disease – an inflammatory disorder of the gastrointestinal tract, a challenge is separating out potential causes from the flood of systemic inflammation inherent in the condition. Researchers led by Subra Kugathasan, MD recently published an analysis that digs under signs of inflammation, in an effort to assess possible causes.
Graduate student Hari Somineni, in Kugathasan’s lab, teamed up with Emory and Georgia Tech geneticists for a sophisticated approach that may have found some gold nuggets in the inflammatory gravel. The results were published in the journal Gastroenterology.
In studying Crohn’s disease, Emory + Georgia Tech researchers may have found some gold nuggets in the inflammatory gravel.
The group looked at DNA methylation in blood samples from pediatric patients with Crohn’s disease, both at diagnosis and after treatment and follow-up. The information came from blood samples from 164 children with Crohn’s disease and 74 controls, as part of the RISK study, which is supported by the Crohn’s & Colitis Foundation and Kugathasan leads.
DNA methylation is a dynamic process that can influence molecular phenotypes of complex diseases by turning the gene(s) on or off. The researchers observed that disrupted methylation patterns at the time of diagnosis in pediatric Crohn’s disease patients returned to those resembling controls following treatment of inflammation
“Our study emphasized how important it is to do longitudinal profiling – to look at the patients before and after treatment, rather than just taking a cross section,” Somineni says.
What part of the intestine is problematic matters more than inflammatory bowel disease subtype (Crohn’s disease vs ulcerative colitis), when it comes to genetic activity signatures in pediatric IBD.
Suresh Venkateswaran and Subra Kugathasan in the lab
That’s the takeaway message for a recent paper in Cellular and Molecular Gastroenterology and Hepatology (the PDF is open access) from gastroenterologist Subra Kugathasan and colleagues. His team has been studying risk factors in pediatric IBD that could predict whether a child will experience complications requiring surgery.
“This study has demonstrated that tissue samples from the ileum and rectum of CD patients show higher molecular level differences, whereas in tissue samples from two different patients with the same type of disease, the molecular differences are low,” Kugathasan says. “This was an important question to answer, since IBD can be localized to one area, and the treatment responses can vary and can be tailored to a localized area if this knowledge is well known.”
Research associate Suresh Venkateswaran, PhD, is the first author on the CMGH paper.
“We see that the differences are not connected to genomic variations,” he says. “Instead, they may be caused by non-genetic factors which are specific to each location and disease sub-type of the patient.”
These findings have implications for other study designs involving molecular profiling of IBD patients. The authors believe the findings will be important for future design of locally acting drugs.
Intestinal inflammation in mice can be dampened by giving them a diet restricted in amino acids, the building blocks of proteins, researchers have found. The results were published online by Nature on Wednesday, MarchÂ 16.
The findings highlight an ancient connection between nutrient availability and control of inflammation. They also suggest that a low protein diet — or drugs that mimic its effects on immune cells — could be tools for the treatment of inflammatory bowel diseases, such as Crohnâ€™s disease or ulcerative colitis.
â€œIt is well known that the immune system can detect and respond to pathogens, but these results highlight its capacity to sense and adapt to environmental changes, such as nutritional starvation, which cause cellular stress,â€ he says.
A idea behind this research is: if we know what parts of the bacteria stimulate healing, perhaps doctors can deliverÂ that material, or something very close, to patients directly to treat intestinal diseases such as Crohn’s or ulcerative colitis.
This ideaÂ has advanced experimentally, as demonstrated byÂ twoÂ papers from Jones and Neishâ€™s frequent collaborator, Asma Nusrat, who recently moved from Emory to the University of Michigan. This team had shown that a protein produced by human intestinal cells called annexin A1 activates ROS, acting through the same N-formyl peptide receptors that bacteria do.
Nusrat told me Friday her team began investigatingÂ annexins a decade ago at Emory, and it was fortuitous that Neish was working on beneficial bacteria right down the hall, since it is now apparent that annexin A1 and the bacteria areÂ activating the same molecular signals.Â (Did you know there is an entire conference devoted to annexins? I didn’t until a few days ago.)
In aÂ secondÂ Journal of Clinical Investigation paper published this February, NusratÂ and herÂ colleagues show that intestinal cells release vesicles containing annexin A1 following injury. The wound closure-promoting effects of these vesicles can be mimicked with nanoparticles containing annexin A1. The nanoparticles incorporate a form of collagen, which targets them to injured intestinal tissue. Read more
What applies to meat, vegetables and fish may also apply to cells for use in cell therapy: frozen often isn’t quite as good.
Ian Copland and colleagues from Emory’s Personalized Immunotherapy Center have a paper this week in Stem Cells Reports discussing how freezing and thawing stem cells messes them up. Specifically, it disrupts their actin cytoskeletons and impairs their ability to find their niches in the body. Culturing the cells for 48 hours after thawing does seem to correct the problem, though.
The findings have some straightforward implications for researchers planning to testÂ cell therapies inÂ clinical applications. The authors conclude:
Until such time as a cryopreservation and thawing procedure can yield a viable and fully functional MSC product immediately after thawing, our data support the idea of using live MSCs rather than post-thaw cryo MSCs for clinical evaluation of MSCs as an immunosuppressive agent.
Notably, the Emory Personalized Immunotherapy Center has built a process designed around offering never-frozen autologous (that is, the patient’s own)Â mesenchymal stem cells, as therapies for autoimmune disordersÂ such as Crohn’s disease.
Can it really be possible to transform a person’s own cells into a weapon against various forms of disease? And what if those very cells could be retrained to attack cancer cells or to prevent autoimmune diseases?
Answers to these questions and many more are about to soon be realized, as Emory University Hospital will serve as the launch site for the very appropriately-named EPIC (Emory Personalized Immunotherapy Center).
The new Center, which is the creation of Dr. Jacques Galipeau, MD, professor of hematology and medical oncology & pediatrics of Emory University, will soon be operational after final touches have been put on construction of the lab. This cell processing facility will foster development of novel personalized cellular therapies for Emory patients facing catastrophic ailments and unmet medical needs.
According to Galipeau, the premise of EPIC and its overlying mission will focus on cellular and biological therapies that use a patientâ€™s own cells as a weapon to seek and destroy cells that actually make a person sick. In partnership with the Winship Cancer Institute of Emory University, Childrenâ€™s Healthcare of Atlanta, Aflac Cancer & Blood Disorders Center and the Emory School of Medicine, EPIC seeks to improve the health of children and adults afflicted with cancer and immune disease.
â€œFirst and foremost, we seek to bring a level of care and discovery that is first in Georgia, first in human and first in child. Blood and marrow derived cells have been used for more than a quarter century to treat life threatening hematological conditions and are now established therapies worldwide. More recently, the use of specific adult somatic cells from marrow, blood and other tissues are being studied in cellular medicine of a wide array of ailments including heart, lung, neurological and immune diseases,â€ says Galipeau. â€œThe use of blood borne immune cells can also be exploited for treatment of cancer, autoimmune disease, organ transplantation and chronic viral illnesses such as HIV.â€
Galipeau said that once operational, EPIC willÂ begin by working with Crohnâ€™s disease in pediatric and adult patients, an inflammatory bowel disease. Symptoms of Crohnâ€™s disease include severe abdominal pain, diarrhea, fever, weight loss, and the inability for a child to properly grow. Resulting bouts of inflammation may also affect the entire digestive tract, including the mouth, esophagus and stomach.Â In some cases, a radical surgery involving the removal of part of the lower intestinal tract is required.
â€œThere is no current answer for what specifically causes Crohnâ€™s disease, nor is there a cure. But we hope that through our research and efforts, we will be able to first target the inflammatory mechanisms in these patients through immunotherapy, and in turn reduce the amount of flare-ups and limitÂ the damage that occurs from this disease,â€ says Galipeau.
Galipeau says the EPIC program could represent a powerful cornerstone to the launch and the development of an entirely new, Emory-based initiative which bundles the strengths of the School of Medicine, Emory University Hospital, Children’s Healthcare of Atlanta, and many Woodruff Health Sciences Center centers of excellence,â€ says Galipeau.
â€œMy ultimate goal is to elevate the biomedical scientific and scholarly enterprise to aÂ higher level – making a difference in the lives of people. The EPIC program and multi-levels of support could be a fundamental underpinning to our success.â€
In the largest, most comprehensive genetic analysis of childhood-onset inflammatory bowel disease (IBD), Emory and Childrenâ€™s Healthcare of Atlanta gastroenterologist Subra Kugathasan, MD, and colleagues identified five new gene regions, including one involved in a biological pathway that helps drive the painful inflammation of the digestive tract that characterizes the disease.
Subra Kugathasan, MD
IBD is a painful, chronic inflammation of the gastrointestinal tract, affecting about 2 million children and adults in the United States. Of that number, about half suffer from Crohnâ€™s disease, which can affect any part of the GI tract, and half have ulcerative colitis, which is limited to the large intestine.
Most gene analyses of IBD have focused on adult-onset disease, but this study concentrated on childhood-onset IBD, which tends to be more severe than adult-onset disease.
Kugathasan and a team of international researchers performed a genome-wide association study on DNA from over 3,400 children and adolescents with IBD, plus nearly 12,000 genetically matched control subjects, all recruited through international collaborations in North America and Europe.
In a genome-wide association study, automated genotyping tools scan the entire human genome seeking gene variants that contribute to disease risk.
The study team identified five new gene regions that raise the risk of early-onset IBD, on chromosomes 16, 22, 10, 2 and 19. The most significant finding was at chromosome locus 16p11, which contains the IL27 gene that carries the code for a cytokine, or signaling protein, also called IL27.
Kugathasan says one strength of the current study, in addition to its large sample size, is the collaboration of many leading pediatric IBD research programs, which included Emory, The Childrenâ€™s Hospital of Philadelphia, the Hospital for Sick Children of the University of Toronto; the University of Edinburgh, UK; Cedars Sinai Medical Center, Los Angeles; and the IRCCS-CSS Hospital, S. Giovanni Rotondo, Italy.
The study, â€œCommon variants at five new loci associated with early-onset inflammatory bowel disease,â€ was published in the November 2009 online issue of Nature Genetics.