Could people living with coeliac disease one day be able to have their cake and eat it, too?

“If the stomach be irretentive of the food and if it pass through undigested and crude, and nothing ascends into the body, we call such persons coeliacs.”

Although coeliac disease is fairly common, affecting about one in 70 people of European descent, it’s still challenging to diagnose and treat. It’s best known for its classic digestive symptoms – diarrhoea and bloating — but it can also manifest in neurological conditions, skin rashes, osteoporosis, infertility and anaemia, or sometimes nothing at all. Children experience failure to thrive, delayed puberty, cognitive and behavioural issues and tooth enamel problems.

“It has such a broad spectrum of symptoms that some people don’t even know they have it,” says Dr Hugh Reid, who’s studying coeliac with his team in the Infection and Immunity group in Monash’s Biomedicine Discovery Institute. “Gastroenterologists think it’s very much underdiagnosed.”

Using the Australian Synchrotron facility, Dr Reid and his team look at how individual protein molecules behave when a coeliac patient ingests gluten. “It’s basically a train wreck.”

First off, gluten contains the amino acid proline. Enzymes in the gastrointestinal tract that break strings of amino acids into smaller fragments, or peptides, can’t chop up proline-heavy proteins very well. “Instead of peptides of just one to a few amino acids long, you can get up to 10 to 20 amino acids on that fragment,” says Reid.

Another thing all coeliac patients have in common is an increased amount of an enzyme called transglutinase 2 (TG2). It transforms one of these amino acids into a version that’s negatively charged, effectively making it “sticky”.

These sticky strings then bind to HLA molecules, specialised protein complexes embedded in the outer surface of our cells. They perform the critical task of scooping up protein fragments and presenting them to T-cells, the roving border patrol of the immune system.

If the receptors on the surface of a T-cell mesh with a peptide on an HLA molecule in just the right way, an alarm goes out and the troops are called in. This is how the immune system distinguishes self from non-self, harmless proteins in food from dangerous bits of bacteria. It’s a complicated system that works astonishingly well – most of the time.

Because there are so many possible combinations of the 20 amino acids, we produce many different HLA molecules to present peptides and many different specialised T-cells to recognise them. Coeliac patients have been dealt a rotten hand here – they have genes that produce one or two HLA versions with a particular affinity for these specific long, sticky strings of gluten residues.

Then, one of their T-cells mistakenly recognises this particular peptide presentation as being harmful, and unleashes a massive inflammatory response that damages the lining of the intestine and produces autoantibodies that can go on to attack other organ systems.

“The thing that makes this extraordinary is that this [peptide presentation] just happens to be the lock that this [T-cell receptor] key fits,” says Reid. “It’s just terribly bad luck.”

Original article 

Rheumatoid arthritis study rated among top by journal

A study by researchers in the Monash Biomedicine Discovery Institute’s (BDI) Infection and Immunity Program has shed light on the structures behind the genetic factor that predisposes people to getting the autoimmune disease rheumatoid arthritis (RA).

The study by first author Dr Yi Tian Ting has been ranked an ‘Editors’ Pick’, among the top-rated papers published by the peer-reviewed ‘Journal of Biological Chemistry’.

“It’s quite an honour to be among the 50 to 100 selected out of 6600 papers published each year,” said Dr Ting, who is profiled in the journal.

“For our article to be recognised among the leading publications that have contributed to this field is always good,” she said.

The researchers investigated the protein MHC Class II, an immune receptor that acts as a sentinel by protecting the body against microbial infection. It does this by presenting small protein molecules from pathogens on its surface, which are subsequently recognised as a threat by cells of the immune system. This in turn leads to an inflammatory response to kill the invading infectious organism.

In autoimmune disease, including rheumatoid arthritis, this can go wrong and the body fails to differentiate between self and foreign protein molecules. In RA, MHC Class II binds to protein molecules from the joint or cartilage that has been modified during inflammation, leading to a damaging auto-immune response.

Although MHC Class II has several subtypes, found in different individuals, certain subtypes are common to RA. This study showed that joint/cartilage-derived protein molecules bound to these RA-associated MHC Class II subtypes in a highly similar way. This makes the binding region common to all a possible target for treatment; a single key that could unlock a common treatment.

The investigators used protein crystallography, a powerful technique allowing them to crystallise the MHC Class II molecule with the bound protein molecules. The crystals were then exposed to radiation at the Australian Synchrotron. The resulting diffraction pattern was used to produce a 3D ‘map’ of the MHC Class II that showed ‘binding pockets’ that might be targeted by potential drugs to prevent the self-proteins from binding.

“Identifying the differences between these subtypes on a molecular basis means that treatment in the future could be more efficient and personalised,” Dr Ting said.

“This may provide insight to why some patients would respond better or worse than others to a particular treatment based on the MHC Class II subtypes they inherited, which are associated with severity and progression of rheumatoid arthritis,” she said.

Currently there is no cure for RA, a complex and debilitating disease.

Dr Ting worked on the paper with senior authors Professor Jamie Rossjohn, Head of the Infection and Immunity Program, and Dr Hugh Reid, Senior Research Fellow, Biochemistry & Molecular Biology, as part of a collaboration with scientists at Janssen Research and Development, part of Johnson & Johnson. The research complements Janssen’s research which includes drug design and patient responses.

Dr Ting said the new Johnson & Johnson Innovation Partnering Office at Monash (JJIPO@MONASH) that opened last fortnight would strengthen the collaboration.

 

Original article

Monash extends collaboration with Janssen on psoriasis prevention

Monash University announced an extension of its collaboration with Janssen Biotech, Inc., one of the Janssen Pharmaceutical Companies of Johnson & Johnson, where researchers will investigate triggers of the immune-mediated disease, psoriasis, and focus on the discovery of potential new treatment approaches to prevent psoriasis.

Professor Jamie Rossjohn, from the Biomedicine Discovery Institute, Faculty of Medicine, will lead the research team at Monash University on the three-year research program.

“We’re delighted to be working alongside Janssen once again in a joint effort to broaden our knowledge around this condition and develop novel treatments for psoriasis,” Professor Rossjohn said.

Original article

Revealed: our cellular guardians

Everyone has a unique identity and awareness of ‘self’ – and this identity has a biological counterpart at the cellular level. This cellular ‘awareness’ is mediated by genes in the human leukocyte antigen (HLA) family, and these genes are the reason, for example, that transplanted organs are rejected unless efforts are made to match HLA types between donor and host.

HLA genes are the ones that vary the most between individuals, and they tag the surface of every cell in our body in a way that denotes precisely who and what we are as biologically individual.

There is, however, another side to these molecules, and it’s been an aspect that has baffled immunologists for decades.

Monash University researcher and Monash Health clinician Professor Richard Kitching explains that, normally, the immune system is trained to not attack ‘self’. Occasionally, this immune ‘tolerance’ breaks down and the result is a painful, life-changing or life-threatening autoimmune disease in which the immune system attacks and damages healthy tissue.

What has baffled immunologists, he says, is that certain HLA gene variants dramatically increase the risk of developing a particular autoimmune disease, while other HLA variants provide impressive levels of protection.

Now, Professor Kitching can explain the HLA effect on disease susceptibility with respect to Goodpasture disease – which was used as the research model – in which the patient’s immune system impairs kidney and lung function.

Even more importantly, the experimental systems developed during this research now provide an opportunity to develop better, cell-based therapies to protect against immune kidney diseases. The findings can also be used to test whether the new cell-based approach is applicable to other autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, Crohn’s disease and multiple sclerosis, he says.

Original article

Sweet success for A/Prof Stephanie Gras

Monash University’s Biomedicine Discovery Institute researcher Associate Professor Stephanie Gras has been honoured with a Georgina Sweet Award for Women in Quantitative Biomedical Science for excellence in the field.

Group leader and Monash Senior Research Fellow in the Department of Biochemistry and Molecular Biology, she was one of three women who won the award, which has a prize of $25,000.

“It’s a great recognition of my career so far and my work in biomedical research, particularly because the award application is reviewed by peers,” Associate Professor Gras said.

“It’s also great to have the opportunity to lead the way for women in science and make sure we can inspire young women to enter science as a career,” she said.

Associate Professor Gras, who is investigating how the immune system can be boosted to counter viruses including influenza and HIV, has several women in her team and plans to use part of the award to ensure they go to conferences next year.

“It gives me the opportunity to snowball the award to make my contribution to supporting women in science,” she said.

 

Original article