Investigating Rhomboid Regulation of ADAM17 in Psoriasis and Skin Biology

Psoriasis is a common skin condition, affecting 2% of the population in the UK. It appears as red raised patches of skin covered with silvery scales. It occurs as a result of "speeding up" of the usual replacement process of the skin. It can also affect the joints, causing inflammation and discomfort. Psoriasis can have a major impact on patients' quality of life because of the disfiguring appearance of the rash and symptoms of discomfort and itch. It has been associated with depression and suicidal thoughts. More recently, it has been shown that these patients have a higher incidence of cardiovascular disease (heart attacks, high blood pressure and stroke).
Many proteins are thought to regulate the inflammation and proliferation of skin in psoriasis. Although there are several treatments available that target these pathways, they are associated with a number of side effects such as liver and kidney damage as well as an increased risk of developing serious infections including tuberculosis.
Our research aims to look a protein called "ADAM17". This is thought to act as a "gate-keeper" within the cell, controlling the release of a number of other proteins into the blood, which in turn cause inflammation and proliferation. We hope to determine how ADAM 17 is regulated in psoriasis.
Our laboratory is in the unique position of two recent discoveries, which will help this research. We have identified a patient in whom ADAM17 is reduced because of a genetic mutation. Secondly, we isolated a group of patients in whom ADAM 17 is increased in association with inherited oesophageal (gullet) cancer. They have a mutation in a gene called 'iRHOM2'. By using information from these two patients we can explore whether iRHOM2 regulates ADAM17.
Using skin cells from these patients we can create three-dimensional models to mimic skin in the laboratory. We can then look at the release of a number of proteins and markers of inflammation. This can be compared with normal skin cells to understand the importance of this pathway on how skin cells behave.
We also hope to directly examine skin specimens from patients with psoriasis and look at the activity of ADAM17 and how it interacts with other proteins including iRHOM2. Finally, we will use a drug which blocks ADAM17 and apply it to skin cells to see whether blocking this pathway could help psoriasis cells behave more similarly to normal skin cells.
Although these pathways will be investigated in psoriasis, the proteins involved are important in a host of other diseases. These include inflammatory bowel and joint disease and a number of cancers. By understanding this pathway in more detail we hope to identify much needed new targets for future drug development.

Background: Psoriasis is a common inflammatory disease. TNFa is thought to play an important role in its development. ADAM17 is a membrane bound-metalloproteinase whose "sheddase" activity includes the release of soluble TNFa. We hypothesise that the rhomboid protein iRHOM2 plays a role in regulating ADAM17. Aims and Objectives:1.Examine the effect of mutated iRHOM2 on ADAM17 expression and inflammatory cytokines. 2.Localisation and expression of iRHOM2 and ADAM17 in psoriatic skin and effect of TNFa blockade 3.The effect of broad-spectrum ADAM inhbitors on keratinocyte behavior and cytokine expression. Methods:1.Keratinocytes derived from patients with mutant iRHOM2 ("Tylosis with Oesophageal Cancer") will be used to form organotypic models, characterized with a panel of proliferation and expression markers including ADAM17 and TNFa. The effects of "knock-down" of iRHOM2 will be assessed. 2.Skin biopsy specimens taken from untreated psoriasis and repeated after initiation of anti-TNFa drugs and will be stained for ADAM17 and iRHOM2 using immunohistochemistry. RTQ-PCR will be used to assess expression of ADAM17 and iRHOM2. siRNA mediated knockdown of iRHOM2 in immortalized psoriatic cell lines will be performed to study the effects on ADAM17, TNFa, TGFa and EGF expression.3.Broad spectrum ADAM inhibitors will be applied to cultured cells from psoriatic and tylosis lines, to assess the impact on cell behavior, proliferation rates and "scratch assays". Immunohistochemistry and confocal microscopy will be used to determine localisation of iRHOM2 and ADAM17. Scientific opportunities: I will learn cell and molecular biology skills including monolayer and complex cell culture, siRNA, western blotting, RT Q-PCR, immunohistochemistry and confocal microscopy. Medical opportunities: Understanding the regulation of ADAM17 could identify novel targetable pathways for the treatment of psoriasis and other inflammatory diseases and malignancies in which TNFa plays a central role.

Psoriasis is a common inflammatory disease, affecting 2% of the UK population. The economic burden is significant, in the USA this amounts to $11 billion per year. The aim of this research project is to identify much needed novel drug targets in the treatment of psoriasis.
The impact of this research is wide-ranging. By understanding the regulation of ADAM17 by Rhomboid proteins in psoriasis we can potentially improve our understanding of TNFa in a number of inflammatory diseases.
These data may be of interest to drug companies in generating new biological agents, specifically monoclonal antibody therapy in the treatment of psoriasis, inflammatory bowel disease, rheumatoid and psoriatic arthritis and potentially malignancies. Such drugs, if effective could broaden the spectrum of available treatments for patients and ultimately reduced the economic and social burden of psoriasis, improving the quality of life for patients and families affected by this disease.
In order to facilitate public engagement in science, we have a purpose built "Centre of the Cell" education centre exclusively based at our research facility. Clinical fellows are trained to become "Volunteer Science Ambassadors" and spend time discussing their research with visitors and students.
We will work with specific patient groups such as the Psoriasis Association UK to disseminate our work to the patient community.