Our group is a drug discovery lab currently working on the development of a novel Fc gamma receptor IIa inhibitors. FcgRIIa is a low affinity receptor for Fc portion of immunoglobulin G (IgG) and is implicated in a variety of conditions that are still mainly untreatable, such as rheumatoid arthritis, lupus, immune thrombocytopenia, sepsis. FcgRIIa is widely expressed by human innate immune cells, and is the only Fc gamma receptor found on human platelets.
Mainly over-stimulation of the FcgRIIa receptor in these conditions that leads to the progression of the disease. For example, in sepsis the platelets get activated via FcgRIIa in response to bacteria present in the blood, which results in thrombocytopenia and disseminated immune coagulopathy. This causes, not only internal haemorrhage but also formation of blood clots that block peripheral blood vessels leading to sepsis-associated limb loss, heart attacks and/or strokes. Using a targeted approach, such as pharmacophore modelling, our group has developed a small molecule compound that effectively blocks FcgRIIa-mediated platelet aggregation in vitro. In agreement with the chosen targeted approach, this compound was shown to bind to the FcgRIIa directly and possesses specificity for the FcgRII subgroup of the Fcg receptors.
Ultimately, this compound has a great potential to be used for treatment of other FcgRIIa-mediated auto-immune conditions, such as rheumatoid arthritis, lupus and an array of immune thrombocytopenia conditions.
Prof Dermot Cox, Dr Tatiana Devine and Padraig Norton
Cystic Fibrosis (CF) is a progressive, genetic disease that causes persistent lung infections and limits the ability to breathe over time. CF is caused by mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene which encodes a chloride channel responsible for helping conduct chloride and other ions across epithelial membranes. Loss of functional CFTR channel disrupts ionic homeostasis resulting in mucus production that clogs the lungs and results in a vicious cycle of chronic infection/inflammation. There are almost 2,000 different variants in the CFTR gene and 70 % of CF patients contain a mutation at position 508, which results in the loss of Phe508 and disruption of the folding pathway of CFTR. ΔF508 CFTR is a trafficking mutant that is retained in the endoplasmic reticulum (ER) and unable to reach the plasma membrane and function correctly as a chloride channel. The Coppinger research lab is focused on understanding the basic mechanisms of CF disease with a focus on the ΔF508 mutation and translating these findings into diagnostics/therapies. We are particularly interested in two areas of research 1. Using basic science technologies to identify novel signalling pathways in CF to discover new CFTR corrector therapies in ΔF508 CF models. We have recently discovered the PI3K/Akt/mTOR signalling pathway to be dysregulated in CF models and a possible therapeutic avenue worth further exploration in CF. Additionally, we are interested in 2. Investigating how diminished ΔF508 CFTR activity leads to heightened inflammatory cell recruitment and CF airway pathogenesis. Exosomes are nanovesicles (40–100 nm) actively secreted by cells and are crucial mediators of intercellular communications. We hypothesised that exosomes may be released from ΔF508 CF patient bronchial cells/fluids and play a role in regulating immune cell function. Preliminary data has confirmed this hypothesis and also indicated exosomal signatures may possibly serve as markers of disease progression in CF. These studies are in collaboration between several groups at the National Children’s Research Centre, Royal College of Surgeons in Ireland, Beaumont Hospital University College Dublin, Cystic Fibrosis Unit, St Vincent’s Hospital.
Last week was another superb week for circadian research in the Molecular and Cellular Therapeutics Department. The Curtis Laboratory published our first big paper on the immune body clock in Nature Communications. This study originated back in 2013. I was still a postdoc in Prof. Luke O’Neills laboratory at Trinity College and was intrigued by some of the studies that showed that multiple sclerosis (MS) was affected by the circadian disruption. A key study showed that teenagers who work shift work before the age of 18 are more susceptible to multiple sclerosis in later life. I wondered if we would see any differences in multiple sclerosis if we disturbed the immune body clock. I approached Prof. Kingston Mills also at Trinity College, who is one of the world leaders of multiple sclerosis and has a key mouse model that recapitulates certain features of MS, called experimental autoimmune encephalomyelitis (EAE). The first experiment we conducted was to see if a mouse which does not have the molecular clock in macrophages was more susceptible to disease, and low and behold it was! This project was driven by one of the most talented researchers that I have ever had the pleasure of working with, Dr. Caroline Sutton, who is a senior postdoctoral fellow in Prof. Mills lab. This project is a great example of collaboration between multiple labs, Mills, O’Neill and my own new group here at RCSI.
And if that wasn’t enough! We also hosted the circadian expert Prof. Qing-jun Meng for our second institutional seminar series on Thursday. Prof. Meng is a world expert on clocks in the musculoskeletal system at University of Manchester. I met Qing-jun in 2013, and have followed his research intensely. He has made seminal discoveries on the impact of the clock on cartilage and invertebral disk function and how this leads to diseases of ageing, such as osteoarthritis and lower back pain. He had the audience enthralled for an hour with his rhythmic images of cells glowing with 24-hour rhythms, and his use of Google searches. It was an absolute pleasure to have Qing-jun with us for the day, and I hope that we can have him back again in the near future.
Some news features on the article can be found here:
Dr Justyna Surowka, Medical University of Lublin, Lublin, Poland
(Current Erasmus Post-doc with the O’Connor group) presented “Assessment of chosen immune cell populations in patients with ovarian cancer”
Despite the decades of studies on developing new therapeutic strategies, ovarian cancer remains one of the malignancies with the highest mortality rate. Therefore, new therapies, among them immunotherapy, are in demand. Recently, Kurman and Shih proposed a new classification of ovarian cancer. It is based on molecular and histopathological differences between tumors and divides them into two subtypes: type I and type II ovarian cancer. However, there are no studies exploring functions of an immune system in those types of ovarian cancer. We demonstrated that each type of ovarian cancer can induce a unique phenotype of dendritic cells and differentiation of Tregs, both associated with immunosuppressive function, which may be an obstacle while developing effective anticancer dendritic cell vaccination.
Dr Sudipto Das presented “Dissecting the epigenome of metastatic colorectal cancer”
The talk highlighted the experimental and analytical pipelines that have been established in the lab in order to develop single-base pair resolution DNA methylation maps derived from difficult-to-handle FFPE (Formalin Fixed Paraffin Embedded) tissue. We next applied these optimized approaches to primary tumour samples derived from 58 metastatic colorectal cancer (mCRC) patients and 10 matched normal samples, with an aim to unravel the methylation alterations across both conventional gene regulatory regions such as promoters as well as alternative regulatory elements such as enhancers of protein-coding and non-coding genes. Intriguingly, we have now identified a DNA methylation specific signature consisting of 377 differentially methylated loci that differentiates tumour and normal and in parallel provides us with three distinctive clinical clusters, which show a significant overlap with prognostically relevant consensus molecular sub-types of CRC. However, further work is warranted to ascertain the precise function of the signature as well as their role in predicting patient response to treatment.
The second part of the talk detailed about the ongoing genomics focused on “n-of-1” genomic studies which essentially involves atypical cancer presentation in patients, with the idea of understanding the biology of such unusual clinical phenotypes and moreover to identify any potential therapeutic targets.
As some of you know, I have joined RCSI as a StAR research lecturer in June. My plan is to establish a lab on ‘MechanoVascular Biology and Microscopy’. What do I mean by this?
The first part ‘MechanoVascular Biology’ sets the scope. I am interested in how cells in the cardiovascular system use mechanical forces to achieve their tasks. As mechanical and chemical cell functions are tightly related, both play important roles in health and disease. Most research has focused on one or the other aspect, but not both. The novel research field of ‘mechanobiology’ takes an integrative approach to better understand how physical forces co-regulate chemical processes on the molecular level. In my previous work at ETH Zurich, I have studied how fibroblasts sense matrix stiffness and respond to it. Here at RCSI, I want to study platelets in the context of thrombosis and, over the years, investigate their interplay with endothelial cells.
The second part ‘Microscopy’ highlights one of the major working horses in my lab. Following the credo ‘seeing is believing’, watching cells can tell you a lot about how they do things. I use microscopy to test hypothesis but also to discover unexpected behaviour. Over the years, I have developed several new microscopy techniques to look at sub-second dynamic processes, directly measure cellular tractions, or determine the nanoscale architecture of multi-protein structures. These are great tools to better understand how the processes starting from platelet activation and ending with the consolidation of the thrombus are regulated in space and time. For this we will use in vitro models, but I am keen to move in the future towards in vivo imaging.
By now, you may have noticed from my scientific viewpoint and my enthusiasm for technology that my background is in physics. I studied physics with a specialization on biophysics at the Technical University Munich. My PhD work at the Max Planck Institute of Biochemistry focused on electrical stimulation of neurons with extracellular electrodes. After a short postdoc at the Ludwig Maximilians University Munich where I studied bi-molecular binding kinetics in living cells, I moved to ETH Zurich in Switzerland. That’s where I have started with mechanobiology and super-resolution fluorescence microscopy, which I know bring over to RCSI.
A long way is lying ahead of me to cross the bridge towards clinical research. I look forward to having many inspiring discussions with you, already thank you for the ones we had so far, and hope that I can make a valuable contribution to the research here at RCSI!
Looking forward to seeing you at MCT Research Talks on 16th October 2017 at 12.00 TR4!
Dr Rebecca Coll is a Research-Industry Fellow at the University of Queensland, studying innate immunity and novel anti-inflammatory drugs. Rebecca received her PhD in Immunology in 2013 under the supervision of Professor Luke O’Neill at Trinity College Dublin and moved to Associate Professor Kate Schroder’s group at the Institute for Molecular Bioscience in UQ in 2014. Over the last five years, her research has focused on inflammasomes – protein complexes at the heart of inflammation and disease – and how these complexes can be targeted therapeutically to prevent damaging inflammation.
Rebecca led the biological characterisation of MCC950, a small molecule inhibitor of the NLRP3 inflammasome and an exciting prospect as a new therapy for treating patients with NLRP3-mediated diseases. In 2016, Rebecca received the Research Australia Discovery Award for her work on MCC950.
The main challenge in treating high-risk neuroblastoma is to combat tumour metastasis and development of resistance to multiple chemotherapeutic drugs. In the native tissue, cancer cells are surrounded by a three-dimensional (3D) microenvironment which provides biological and physical support and determines disease initiation, progression, patient prognosis and response to treatment. The conventional two-dimensional (2D) cell culture lacks this feature resulting in discrepancies between in vitro and in vivo results. Current neuroblastoma studies employ either 2D cell culture systems or murine models or alternatively a mix of both.
In collaboration with Dr Caroline Curtin and Prof Fergal O’Biren (TERG), we decided to bridge the gap between 2D culture and in vivo tumours in neuroblastoma research by developing a tissue-engineered cell culture model of neuroblastoma. This project is supported by a pilot grant from Neuroblastoma UK.
To understand what signalling pathways are activated in 2D, 3D and in vivo neuroblastoma models, we decided to look closer at the differences between conventional 2D neuroblastoma cells and their xenografts. This way we hope to find those targets that are activated in both tumour microenvironment and the 3D tissue engineered models. Ciara and Larissa have begun this search by profiling xenograft samples with a panel of antibodies. Ciara became particularly fascinated by the elevated levels of c-jun, TCF1 and LEF1 in cisplatin-resistant neuroblastoma xenografts suggesting that the development of cisplatin resistance in neuroblastoma may be accompanied by activation of the wnt/b-catenin pathway in vivo. Larissa identified that cisplatin-resistant neuroblastoma cells secrete chromogranin A (CgA) at levels higher that cisplatin-sensitive cells. CgA levels also correlated with increased vascularisation and volume of murine orthotopic neuroblastoma xenografts. Altogether it suggests that CgA can be used as a marker of neuroblastoma cell growth both in vitro and in vivo.
Research talks were presented by Sheila Zarros, Tatyana Devine, Afnan Ali and Padraig Norton. Tatyana and Sheila were talking about challenges in thecharacterisation of novel FCγRIIa inhibitors.
Fc receptors are a widely distributed family of receptors that mediate cellular responses to antibodies or immunoglobulins (Ig). The Fc gamma receptor II, FcgRII (also known as CD32) is a low-affinity receptor for Fc portion of immunoglobulin G (IgG) and has two isoforms FcgRIIa and b. Fcg RIIa is widely expressed by human innate immune cells and is the only Fc gamma receptor found on human platelets.
Our group and others have demonstrated the significance of this receptor in the activation of platelets by bacteria, suggesting that it could be an important target in the treatment of sepsis. Its implications in rheumatoid arthritis, cancer pathogenesis, allergic reactions and flu virus-induced thrombocytopenia were also demonstrated.
Our project is focused on characterisation of novel small molecule compounds designed for targeting FcgRIIa receptor’s IgG binding site to inhibit bacteria-induced platelet aggregation in primary human plasma and investigation of their interactions with the FcgRIIa using surface plasmon resonance technology.
Afnan Ali reported on the role of the Fc gamma Receptor IIa (FcγRIIa) in platelet activation. Platelets express the FcγRIIa and this receptor has been identified as a key receptor in bacterial activation of platelets leading to thrombocytopenia and platelet activation. The aim of this study was to identify drugs that could be re-purposed for the treatment of sepsis and immune-mediated thrombocytopenia. We identified 42 drugs predicted to inhibit binding of IgG1 to the FcγRIIa using virtual high throughput screening. This included 20 antibacterial agents, 3 anti-fungals, 3 antiviral agents, 7 antineoplastics and 3 immunosuppressives. A selection of drugs were tested for inhibition of platelet adhesion to IgG, S. aureus-induced platelet aggregation and assessed for platelet activation. This work has identified multiple drugs that have potential to be to be repositioned for thrombocytopenia, sepsis and autoimmune disorders, as well as providing a possible mechanism of action to explain the immunosuppressive effects of some anti-neoplastics and immunosuppressive drugs.
Prof. Eric S. G. Shaqfeh, Qin M. Qi, Departments of Chemical and of Mechanical Engineering, Stanford University
The inhomogeneous center-of-mass distribution of red blood cells and platelets normal to the flow direction in small vessels plays a significant role in hemostasis, drug delivery and microfluidics. Under pressure-driven flow in channels, the migration of deformable red blood cells at steady state is characterised by a concentration peak at the channel center and a cell-free layer or Fahraeus-Lindqvist layer near the vessel wall.
Rigid particles such as platelets, however, “marginate” and thus develop a near-wall excess concentration. This margination controls the time it takes for the initial stages of platelet binding and clotting in response to trauma.
In this talk, we investigate the time-dependent concentration distribution of red blood cells and platelets in pressure-driven flow by developing and solving a Boltzmann model, advection-diffusion equation for both species. From a fluid mechanics point of view, deformability-induced hydrodynamic lift and shear-induced diffusion are essential mechanisms for the cross-flow particle migration and margination. The governing equation for the distribution of red blood cells includes both lift flux away from the wall and shear-induced diffusion due to cell-cell “collisions”. On the other hand, the governing transport equation for platelets includes shear-induced diffusion from cell-platelet “collisions” and platelet-platelet “collisions”. We demonstrate that these predictions are in good agreement with full boundary element simulations of the margination process and we also compare directly to experimental results. We then examine, within this model and our full boundary element simulations, the time evolution and “entrance length” for red blood cell migration and platelet margination. The resulting complete model can serve as a fast and computationally efficient alternative to large-scale simulation with the application, for example, as a real-time computational tool for microfluidic blood assay systems.
Cardiovascular disease (CVD) is the leading cause of death and disability in the world (approx. 1.9 million deaths per year within the EU). Platelet’s play a key role in this process and hence is why antiplatelet therapy such as aspirin is effective in reducing its incidences. Platelet function testing has a role in identifying those that are at high risk of a CVD related event (example a heart attack) and also identifying those patients that do not respond to their medication. There are a number of platelet function tests on the market however these tests suffer from a number of disadvantages such as expense, high sample volume, requirement for trained lab personal and single drug test capability.
My current research under the supervision of Prof. Dermot Kenny (RCSI) and Dr. Niamh Gilmartin (DCU and DIT) is to work alongside our multi-disciplinary team to produce a cost effective, rapid, small sample volume platelet function assay which can detect the effect of multiple antiplatelet drugs in a single patient blood sample. The project is known as the Platelet Monitoring Biochip (PMB). The PMB device consists of 6 micron sized fibrinogen dots, which are micro contact printed to a Zeonor (plastic) surface, a bright-field imaging system and a custom designed platelet analysis software. Blood is added to the device and rocked for 30 minutes to allow platelets to adhere to the fibrinogen dots. The device has 3 channels, a control (no agonist well), an adenosine diphosphate (ADP) well and an Arachidonic acid (AA) well which can be used to detect P2Y12 platelet inhibition and aspirin effect simultaneously. The PMB device provides a fast, easy and low cost way to determine the effectively of antiplatelet therapy against multiple agonists in whole blood. The device is currently in operation in RCSI Beaumont.