Lupus, multiple sclerosis, and type-1 diabetes are among more than a score of diseases in which the immune system attacks the body it was designed to defend. But just why the immune system begins its misdirected assault has remained a mystery.

Now, researchers at Temple University School of Medicine (TUSM) have shown that bacterial communities known as biofilm play a role in the development of the autoimmune disease systemic lupus erythematosus — a discovery that may provide important clues about several autoimmune ailments.

A team led by TUSM researchers Çagla Tükel, PhD, and Stefania Gallucci, MD, show how bacterial biofilms found in the gut can provoke the onset of lupus in lupus-prone mice. Dr. Tükel is an Assistant Professor of Microbiology and Immunology at TUSM, and Dr. Gallucci is Associate Chair, Microbiology and Immunology, as well as an Associate Professor in Microbiology and Immunology at TUSM. Both are members of the Temple Autoimmunity Center.

‘This work stresses the importance of considering infections as a possible trigger for lupus,’ Dr. Gallucci said. ‘Very little was known about how biofilms interact with the immune system because most of the research has been looking at how biofilms protect bacteria, how they make bacteria resistant to antimicrobials such as antibiotics, but almost nothing was known about what biofilms do to the immune response,’ she said.

Biofilm is a densely packed bacterial community that excretes proteins and other substances. Those substances form a matrix that protects the bacteria from antimicrobials, the immune system, and other stressors. Biofilms can occur in our guts, among the bacteria that help us digest. They exist as dental plaque, or arise in urinary tract infections. They also can find a home on man-made surfaces such as intravenous catheters. Central to the lupus story is a biofilm protein deposit called an amyloid. In the common gut bacteria E. coli, as well as the bacteria often responsible for severe gastrointestinal distress that accompanies food poisoning, Salmonella Typhimurium, amyloids are called curli because of their curly fibre-like appearance.

Also part of the biofilm is DNA excreted by bacteria. The Temple team discovered that when curli amyloids and DNA meet, they form remarkably durable bonds in the biofilm. When the researchers attempted to separate the DNA from these bonds using a variety of enzymes as well as chemicals, the curli wouldn’t let go. Curli-DNA complexes speed up the creation of the biofilm, the researchers learned. And the Temple researchers found it is also in this composite of curli-plus-DNA that autoimmune trouble appears to arise.

It’s long been known that infection is associated with lupus flares — a flare in lupus is when symptoms worsen. Indeed, infections play a role in between 20 percent and 55 percent of lupus patient mortality. Up to 23 percent of hospitalizations in lupus patients are due to infectious disease complications. Further, the bacteria Salmonella are more aggressive in lupus patients, with the ability to create potentially lethal complications.

The new research shows that the complexes formed from curli amyloid and DNA in the biofilms of both Salmonella and E. coli give rise to not only inflammation, but the self-attacking antibodies of lupus.

To demonstrate the role of biofilms in immune response, the researchers wanted to see how the sentinels of the immune system, called dendritic cells, reacted to a biofilm. The dendritic cells sent ‘tendrils’ into the biofilm and ate up part of it to signal other molecules. Further, they produced large amounts of chemicals called proinflammatory cytokines. These cytokines are important in inciting the immune system to act. Among the cytokines was Type-1 interferon, known to be associated with lupus.

‘I was super excited when I saw how activated the dendritic cells were on the biofilm ‘ Dr. Gallucci said. The levels of cytokines released when dendritic cells were exposed to curli-DNA complexes actually exceeded the most robust response known previously — the response to lipopolysaccharide (LPS).

To test if the immune response seen in the laboratory would be enough to induce autoimmunity and the attack on self that occurs in lupus, the researchers used mice that are prone to develop autoimmune disease. As is the case with many diseases, lupus is the result of a genetic propensity that lies dormant in the absence of an environmental trigger. The researchers wanted to see if the curli-DNA complexes could provide that trigger. They injected susceptible mice with the amyloid-DNA composites or a placebo. Within two weeks, the researchers found the kind of antibodies that attack ‘self,’ known as autoantibodies. The autoantibodies, which target double-stranded DNA, are a diagnostic hallmark of lupus. The response was remarkably fast. It normally takes mice four to five months to develop autoantibodies.

Another strain of mice that do not develop lupus spontaneously but are genetically predisposed to autoimmunity also reacted to the curli-DNA composites with rapid production of autoantibodies. A third strain of mice with no propensity for any autoimmune disease, developed autoantibodies within two weeks of injection, but at lower levels than in the mice with a propensity toward lupus.

All mice developed the autoantibodies whether the curli-DNA composites came from Salmonella or from the kind of E. coli that’s found in a healthy digestive system. In fact, three of the four bacterial families that contain curli genes are found in the gut: Bacteroidetes, Proteobacteria, and Firmicutes, suggesting a possible source of vulnerability in susceptible patients. ‘How that happens, I think that will be the next level of our project,’ Dr. Gallucci said. The research team is already looking at mouse models to see what may lead to the escape of curli-DNA complexes from the gut. Further, the team is collaborating with rheumatologist Dr. Roberto Caricchio, Director of the Temple Lupus Clinic, to see if the patients show signs of exposure to the curli-DNA complexes.

‘The next step is to explore the mechanism of how these composites are stimulating autoimmunity,’ Dr. Tükel said. ‘The beneficial bacteria found in our guts can cause problems when they cross the intestinal barrier and reach to places they shouldn’t be. Thus, besides infectious bacteria, a leaky gut could cause many problems. We are now starting to understand how the bacteria in our gut may trigger complex human diseases including lupus. So it’s critical for us to understand the biology of the bacterial communities and their interactions with the immune system.’ EurekAlert

Insulin resistance affects tens of millions of Americans and is a big risk factor for heart disease. Yet, some people with the condition never develop heart disease, while some experience moderate coronary blockages. Others, though, get severe atherosclerosis – multiple blockages and deterioration of coronary arteries characterized by thick, hard, plaque-ridden arterial walls. Researchers at the UNC School of Medicine created a first-of-its-kind animal model to pinpoint two biomarkers that are elevated in the most severe form of coronary disease.

The study suggests two new targets – oxidized LDL cholesterol and glycated proteins (i.e., fructosamine or haemoglobin A1c) – that researchers can further investigate and perhaps target through medications to help people with insulin resistance avoid the worst kind of heart disease.

“If these correlations were also found in insulin resistant humans, then we would want to do everything we could to treat them because they would be at a very high risk of developing severe cardiovascular disease,” said Timothy Nichols, MD, professor of medicine and pathology and first author of the PLoS One paper.

Interestingly, Nichols and his colleagues did not set out to pinpoint the two key biomarkers. They wanted to create an insulin resistant animal model that mimicked human heart disease. They chose pigs, which are metabolically similar to humans and have hearts very much like human hearts. By feeding the animals a diet high in fat and salt over the course of a year, all the pigs became insulin resistant. That is, their bodies produced a lot of insulin but their cells did not respond to the hormone as well as normal. All the pigs also developed coronary and aortic atherosclerosis. But only about half of the pigs developed the most severe form of the disease.

When the researchers checked the pigs for high levels of insulin resistance, they found no correlation with the most severe atherosclerosis. This was a surprising and unexpected finding.

David Clemmons, MD, the Sarah Graham Kenan Professor of Medicine, professor of biochemistry and biophysics, and senior author of the PLoS One paper, knew that the scientific literature suggested a correlation between atherosclerosis and glycated proteins – proteins bonded with sugars in blood.

Clemmons and colleagues tested the pigs for high levels of fructosamine and oxidized LDL cholesterol, which are surrogates for high levels of glycated proteins. Sure enough, all the pigs with severe heart disease had elevated levels of fructosamine and oxidized LDL.

“Also, this correlation was more common in females,” Clemmons said. Fourteen of the 20 pigs that developed severe atherosclerosis were females. Fourteen of the 17 pigs that did not develop severe atherosclerosis were male. “This surprised me, so I looked in the literature for anything similar.”

Clemmons found a study from Finland published in 2005 showing that elevated glycated protein levels were strongly associated with advanced heart disease and increased mortality in women but not in men.

“The underlying causes of this correlation are unknown,” Clemmons said. “But now we have a unique animal model that very much mimics what we see in humans. Our model is a good predictor of diet-induced atherosclerosis in females.”

A next step could be to study the affected heart tissue to find abnormal biochemical reactions in the cellular pathways involved in glycated proteins and severe coronary disease.  This could lead to potential new treatment approaches or tailored dietary interventions. University of North Carolina Health Care

Practically everyone gets fatter as they get older, but some people can blame their genes for the extra padding. Researchers have shown that two different mutations in a gene called ankyrin-B cause cells to suck up glucose faster than normal, fattening them up and eventually triggering the type of diabetes linked to obesity.

The more severe of the two mutations, called R1788W, is carried by nearly one million Americans. The milder mutation, known as L1622I, is shared by seven percent of the African American population and is about as common as the trait for sickle cell anaemia.

The findings, which were generated in mice, could help identify at-risk individuals who might be able to tip the scales back in their favour by eating better and exercising more.

“This is one of the first examples of a susceptibility gene that would only be manifested through a modern lifestyle,” said Vann Bennett, M.D., Ph.D., senior author of the study and George Barth Geller Professor of Biochemistry, Cell Biology, and Neurobiology at Duke University School of Medicine. “The obesity epidemic really took off in the 1980’s, when sugary sodas and French fries became popular. It’s not like we suddenly changed genetically in 1980, but rather we have carried susceptibility genes that were exacerbated by this new diet. We think our findings are just the beginning, and that there are going to be many genes like this.’

Bennett, who is also an investigator with the Howard Hughes Medical Institute, discovered ankyrin-B more than thirty years ago. He found that ankyrin-B acts as a kind of protein anchor, tethering important proteins to the inside of the cell’s plasma membrane. Since his initial discovery, Bennett and other researchers have implicated defects in ankyrin-B in a wide variety of human afflictions, including irregular heartbeat, autism, muscular dystrophy, aging, and, more recently, diabetes.

Diabetes is quickly becoming one of the greatest threats to public health, as waistlines expand around the world and here in the United States. If the current trends continue, one in three Americans will have diabetes by 2050. Patients with type 1 diabetes do not make enough insulin, the hormone that helps process the glucose that builds up in the bloodstream after a meal. Patients with type 2 diabetes, the form linked to obesity, make insulin but become resistant to its effects.

Several years ago, the Bennett laboratory found evidence that ankyrin-B mutations might play a role in insulin secretion and metabolism. Since then, several studies have uncovered rare ankyrin-B variants that are associated with type 2 diabetes. One mutation, called R1788W, was more common in Caucasians and Hispanics. Another, called L1622I, was found exclusively in African-Americans, a group known to be at a particularly high risk of diabetes. But it was still unclear how these changes in the genetic code could set a course for diabetes.

To get at that answer, Bennett’s MD/PhD student Jane Healy created mouse models that carried these same human genetic variants. She and her colleagues found that animals with two copies of the R1788W mutation made less insulin than normal mice. Despite this shortcoming, their blood glucose levels were normal. So the researchers performed the rodent equivalent of a glucose tolerance test –- commonly used to screen for type 2 diabetes in people — to determine how quickly glucose was cleared from the bloodstream in the mutant mice. To their surprise, the mutant mice metabolized glucose more quickly than normal mice.

“We thought that the main problem in these mice would be with the beta cells that produced and secreted insulin,’ said Healy, co-author of the study and a former trainee in Bennett’s laboratory. “Instead, our most significant finding lay with the target cells, which took up much more glucose than expected.”

Glucose doesn’t enter cells and tissues all on its own, but instead has to rely on a second molecule, called GLUT4 transporter, to gain access. Normally, GLUT4 hangs out in the cell, like a hostess waiting for party guests to arrive. When insulin is present it acts as a kind of doorbell, alerting GLUT4 to spring into action and open the door to let glucose into the cell. When insulin goes away, the GLUT4 transporters close the door, turn around, and go back into the middle of the cell.

However, postdoctoral fellow Damaris Lorenzo, Ph.D., found that wasn’t the case with the mutant mice. After conducting a number of biochemistry experiments, Lorenzo ddiscovered that the mice had lots of GLUT4 on the surface of their muscle and fat cells even when there wasn’t any insulin around. That meant that glucose could flow in without necessarily having to bother with the doorbell.

This open door policy was an advantage when they were young, because it protected the animals from low insulin levels. But when the mice got older — or switched to a particularly high-fat diet — it made the mice fatter and, eventually, led them to become insulin resistant.

The researchers believe that long ago, the R1788W mutation — and the milder L1622I mutation — may have provided an evolutionary advantage. Aging hunter-gatherer types, who weren’t as effective at chasing down their next meal, needed to gain as much fat as possible to avoid starvation. Now that high-fat, high-calorie foods are plentiful in much of the world, these variants put people at increased risk for modern afflictions like obesity and diabetes. Duke University

Despite modern chemoradiation therapy it is still very difficult to give reliable prognoses for malignant gliomas. Surgical removal of the glioma is still the preferred method of treatment. Doctors at Universitätsklinikum Erlangen’s Department of Neurosurgery have now developed a new procedure for analysing radiological imaging scans which makes it possible to predict the course of a disease relatively precisely.

The Friedlein Grading A/B (FGA/B) classification system – named after the physician Katharina Friedlein – is a quick and precise way of determining whether surgical removal is the best possible treatment method for a given tumour. Essentially, the Erlangen-based doctors classify tumours according to their position in the brain in the context of a routine magnetic resonance imaging (MRI) scan. Tumours that are not located in functional brain regions or that are located at a certain distance from such regions are classified as FGA, while tumours that are close to or inside a functional brain region are classified as FGB.

With the FGA/B method it possible to plan the consequences of tumour surgery, which is crucial for the success of the treatment, in a precise, low-risk and quantitative manner. This makes the Friedlein Grading system the first classification system which can be easily applied in clinical practice. ‘There have already been several attempts in medicine to develop such a classification system. However, most approaches were too complicated and were based on academic values only, which made it difficult to use them in clinical practice,’ says PD Dr. Nicolai Savaskan from FAU’s Chair of Neurosurgery. ‘The FGA/B method can be applied on the basis of a standard MRI scan which glioma patients have to undergo anyway and is highly reliable despite being so simple. We hope that our colleagues in neurosurgery departments in smaller hospitals will also be able to use it successfully in everyday clinical practice.’ Universitätsklinikum Erlangen