Autoimmune diseases and mood-related disorders are among the major plagues of our modern society, as they impair the normal daily life of patients at both social and physical levels. Autoimmunity is caused by the loss of immunological tolerance i.e. the inability of immune cells to make a distinction between self and non-self antigens. Intriguingly, patients suffering from autoimmune diseases also show higher rate of “unjustified” mood disorders, such as depression and anxiety. Recent evidence indicates mood disorders as biomarkers for autoimmunity rather than co-morbidities since their occurrence is unrelated to the time of diagnosis of the autoimmune disease or to the degree of disability. In this thesis I investigated the phenotype of T cell-specific transgenic mice overexpressing Annexin-A1 (AnxA1tg): homeostatic immunomodulatory protein with dual opposite functions in the innate and adaptive immune system. Consistent with the previously observed pro-inflammatory role in T cells, AnxA1tg mice showed higher susceptibility to develop autoimmune diseases like multiple sclerosis and systemic lupus erythematosus. Most interestingly, using a battery of behavioural tests, we showed an increased anxious-like behaviour in AnxA1tg mice compared to wild type. This phenotype was associated with a specific gene pattern in the brain and in T cells as shown by microarray analyses. Adoptive transfer of AnxA1tg-CD4+ T cells into wild-type mice caused an increased anxiety-like behaviour in the recipient animals thus providing first experimental evidence for emotional dysfunction in autoimmunity-prone animals. In conclusion, the results of this study provide novel evidences for the strong link between immune system and CNS. More specifically, our findings highlight a novel function of CD4+ T cells as the drivers of mental and physical wellbeing. Future studies will assess the potential of strategies targeting AnxA1 in T cells as new therapeutic tools for the combined treatment for autoimmunity and associated mental disorders.

A school of literature has shown that Annexin-A1 (Anx-A1) is an endogenous anti-inflammatory protein that exerts a regulatory control over the innate immune system in order to restore homeostasis after an inflammatory reaction. Surprisingly, recent published works have highlighted that Anx-A1 has an alternate role in the adaptive immune system by positively modulating the strength of TCR signalling and biasing helper-subset differentiation. Dendritic cells are a class of innate leukocytes, poised at the environmental interface, that are the essential immune cells responsible in the initiation of T-cell driven responses. These findings provided the foundation for this PhD project, the principal aim of which is to provide a link between the disparate effects of Annexin-A1 in innate and adaptive immunity by investigating the role of endogenous Annexin-A1 in dendritic cell biology and its effector function as an antigen-presenting cell towards T cell activation and differentiation. To address this hypothesis, I cultured bone marrowderived dendritic cells from AnxA1-deficient mice or control littermates and stimulated with LPS (100ng/ml) then compared phenotypic and functional characteristics. My results demonstrate that Anx-A1-/- bone marrow derived dendritic cells show an increased number of CD11c+ cells expressing high levels of some maturation markers such as CD40, CD54 and CD80 and a decreased capacity to take up antigen compared to control Anx-A1+/+ cells. However, analysis of LPS-treated dendritic cells from Anx-A1-/- mice demonstrated a diminished up-regulation of maturation markers, a decreased migratory activity in vivo and an attenuated production of the inflammatory cytokines Interleukin (IL)- 1β, Tumour Necrosis Factor (TNF)-α and IL-12. This defect was resultant of an impaired Nuclear Factor (NF)-κB/DNAbinding activity due to lack of Anx-A1 signalling as demonstrated by the reduced activation of Extracellular-signal Regulated Kinase (ERK) 1/2 and protein kinase B (PKB)/Akt compared to cells from control littermates. As a consequence of these defects, I assessed the antigenpresenting/ T-cell activating capabilities of these DC. Anx-A1-/- DC showed an impaired capacity to stimulate T cell proliferation and differentiation in allogeneic mixed leukocyte reaction. To dissect this biologically relevant phenomenon further, I employed an antigenspecific, T-cell restricted model; a co-culture system of chicken ovalbumin peptide-pulsed, LPS-matured bone marrow-derived DC incubated with transgenic TCR T cells from OT-I/RAG-1-/- (OT-I, OTI/ CD8+) or OT-II/ RAG-1-/- (OT-II, OT-II/CD4+) mice. Peptide-pulsed, LPS-matured AnxA1-/- DC failed to initiate an appropriate T cell activation in both OT-I and OT-II T cells indicated by reduced cell proliferation when compared to T cells co-cultured with peptide6 pulsed, LPS-matured AnxA1+/+ DC. Additionally, comparison of peptide-pulsed, LPS-matured AnxA1-/- DC with AnxA1+/+ DC counterparts detected severely diminished levels of IL-2 from cocultures with OT-I T cells and ablated IFN-γ production from cocultures with both OT-I and OT-II T cells. In conclusion, AnxA1 seems to act as a positive modulator of immunogenic activation of DC, whereby the AnxA1 signal pathway has a probable synergism with the TLR4 signalling cascade. DCderived AxnA1 appears to contribute in promoting T cell activation with a larger influence on OT-I/CD8+ T cells than OT-II/CD4+ T cells. Altogether these findings suggest that inhibition of Anx-A1 expression or function in dendritic cells might represent a useful way to modulate the adaptive immune response and pathogen-induced T cell-driven immune diseases.

Microparticles (MP) are submicron structures produced by all cells upon activation or apoptosis that act as a non-soluble means of communication between cells. They ferry proteins, bioactive lipids, RNA and receptors, as well as ridding cells of redundant organelles and toxins. They have been recently investigated for their pathophysiological role and as potential biomarkers/effectors in many diseases. In severe sepsis, studies of MP so far have produced inconsistent and even conflicting results. In this project, it was demonstrated that cell derived MP subsets vary according to the cause of severe sepsis (community acquired pneumonia (CAP) or faecal peritonitis (FP)), where CAP patients had higher levels of circulating MP. Surprisingly, FP patients MP levels were comparable to healthy volunteers. Further stratification of MP subsets according to their expression of the protein alpha-2-macroglobulin (A2M) has yielded better differentiation between the two diseases. The A2M expressing MP were significantly higher in survivors of community acquired pneumonia sepsis, but there was no similar association in patient with FP. Granulocyte macrophage colony-stimulating factor (GM-CSF) and interferon γ (IFN-γ) are being studied as possible adjuvant therapies in sepsis. They seem to reverse the immune-paresis that ensues after the initial insult. MP produced from whole blood stimulated with GM-CSF and IFN-γ were studied in this project. Both GM-CSF and IFN-γ increased MP expressing A2M over control. These MP elicited a pro-inflammatory phenotype when incubated with neutrophils or endothelial cells which may contribute to the potential benefits of GM-CSF and IFN-γ in severe sepsis.

Studies have demonstrated the immune system to be significantly more plastic than previously believed. Multiple external factors have been shown to influence the immune response including alterations to the host's external environment and psychological status. This thesis details an investigation of this influence; exposing male CD1 mice to a two-week environmental enrichment paradigm then subjecting them to one of a range of inflammatory disease models chosen to assess a specific aspect of their immune function. Enriched animals were found to possess significantly higher numbers of circulating innate leukocytes compared to those animals housed in a standard lab environment. This leukocytosis was found to persist when animals were subject to a model of zymosan-induced peritonitis, where enriched animals presented an enhanced neutrophil and macrophage influx into their peritoneal cavity. Similar results were observed in a model of sepsis induced by caecal ligation and puncture where enriched animals were also found possess an enhanced capacity for systemic bacterial clearance. Across both experiments no changes in inflammatory cytokine expression were observed between enriched and standard environment animals. Genomic and proteomic profiling supported these findings, revealing the increased expression of immune-modulatory genes associated with a heightened immune and moderated inflammatory response. Ex vivo analysis of leukocytes extracted from enriched animals showed they also possessed enhanced phagocytic function and an accompanying reduction in gene expression associated with heightened cytotoxic function. When subject to a model of persistent inflammation induced by sponge implantation, enriched animals again presented heightened leukocyte infiltration to the point of immune insult. This was accompanied with a reduction in the release of pro-inflammatory cytokines and the heightened expression of genes associated with a pro-resolving, wound healing phenotype. This study provides novel insights into the mechanisms by which environmental modulation may influence the immune response and of the potentially immune-protective influence of environmental enrichment.

Omega-3 fatty acids (ω-3 FA, including eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]), are essential polyunsaturated fatty acids which are correlated with lower incidence of chronic diseases. DHA and EPA can be enzymatically converted to resolvins, protectins and maresins, which play important roles in resolution of inflammation. Additionally, ω-3 FA can also directly activate surface receptors, namely the long-chain free fatty acid receptors GPR40 and GPR120, two GPCRs with poorly investigated biology. Using real-time PCR analysis, GPR40 transcript in human neutrophils was detected; the protein expression was also confirmed by flow cytometry and image stream analysis. Expression of GPR40 protein was up-regulated after stimulation with platelet-activating factor (PAF, 10nM) or leukotriene B4 (LTB4, 10nM) for 10 minutes. I utilised the selective agonist GW9508 to investigate the biology of GPR40. Tested on human neutrophils, GW9508 elevated intracellular calcium when applied within the 0.1-10μM range. The up-regulation of GPR40 expression by pro-inflammatory stimuli suggested to us potential regulatory roles for this receptor during inflammation. I then showed that 1 and 10μM GW9508 increased neutrophil chemotaxis in response to the cytokine IL-8 (30ng/ml). In addition, GPR40 activation by GW9508 enhanced phagocytosis of E. coli by human neutrophils by approximately 50% when tested at 0.1 and 1μM. Moreover, GW9508-neutrophil stimulation augmented microvesicle release and delayed apoptosis after stimulation. Finally, I demonstrated that GPR40 is expressed in inflammatory cells isolated from murine arthritic joints, such as neutrophils, macrophages and inflammatory monocytes. KBN-serum induced arthritic mice developed a more severe disease when treated prophylactically with GW9508 (10mg/kg, i.p. treated from day 0, daily), characterized by a higher clinical score and increased oedema when compared to vehicle control mice. Therapeutic intervention with GW9508 at the peak of the disease (day 5) delayed the resolution of arthritis. In summary, the data suggest that activation of GPR40 by GW9508 enhances neutrophil activation, up regulating the pro-inflammatory properties of this cell type, and therefore, exacerbating experimental inflammatory arthritis.

Disease progression in Multiple Sclerosis (MS), an autoimmune disease of the CNS, is widely accepted to be due to persistent myelin loss (demyelination) coinciding with lost nerve cells and nerve fibres (neuroaxonal loss). Current treatments are immunomodulatory and do not address the neuroaxonal or demyelinating pathology of the disease. It is hypothesised that a lack of growth factors within the CNS may result in the failure of remyelination. Therefore, biologics such as recombinant therapeutic proteins used for gene therapy offer a promising therapeutic intervention to the progressive stages of the disease. However, due to the short half-lives of these therapeutics and their pleiotropic effects, there is cause for concern over their safety and efficacy. Using LAP technology (the fusion of the therapeutic protein with the latent associated peptide [LAP] of TGFβ), the half-life of the therapeutic protein can be increased and can be targeted to sites of inflammation and disease. This study aimed to investigate the potential neuroprotective, remyelinating and anti-inflammatory effects of latent versions of the growth factors erythropoietin (EPO), insulin-like growth factor 1 (IGF1) and transforming growth factor beta (TGF) respectively. Firstly, using molecular cloning techniques, these growth factors were individually fused and linked to the LAP of TGF via a matrix metalloproteinase (MMP) cleavage site resulting in three latent growth factors. Secondly, these latent growth factors were shown to be expressed, and to be biologically active in vitro when released by MMP cleavage. Finally, syngeneic fibroblasts were engineered to express the latent growth factors. It was found that, in CREAE, the fibroblasts engineered to produce latent TGF significantly reduced the disease clinical score as compared to controls whilst latent EPO produced by transduced fibroblasts failed to exert a statistically significant effect on disease progression. Nonetheless, this study demonstrates the feasibility of the latency platform technology to generate latent therapeutics with the ability to act as an intervention to disease progression in MS.

G–Protein Coupled Receptors are one of the most important targets in drug development, making up over 60% of drug targets. Recent studies have implicated a role of Regulator of G–Protein Signaling (RGS) proteins in the development and progression of pathologies, including some cancers. RGS17, the most–recently identified family member of the RZ family of RGS proteins, has been implicated in the growth, proliferation, metastasis and migration of prostate tumors as well as small–cell and non–small cell lung cancers. In neoplastic tumor tissues RGS17 is up–regulated 13 fold over patient–matched normal tissues in prostate cancer. Studies have shown that RGS17 RNAi knockdown inhibits colony formation and decreases tumorigenesis in nude mice. Based on these findings, this thesis explores the research undertaken to develop small molecule inhibitors of the RGS17: Gαo protein: protein interaction. In this thesis, we implemented AlphaScreen® technology to develop a high–throughput screening method for interrogating small molecule libraries for inhibitors of RGS17. Chapter 3 focuses on the initial results of the AlphaScreen® in 384–well format. The screen utilizes a measurement of the Gα: RGS17 protein: protein interaction (PPI) and with an excellent Z–score exceeding 0.73, a signal to noise ratio >70 and a screening time of 1,100 compounds per hour. Chapter 3 presents the development, validation and initial high–throughput screening for inhibitors of Gα: RGS17 interaction as well as preliminary characterization of the RL series of hits. In this pilot screen the NCI Diversity Set II was interrogated, yielding 35 initial hits of which 16 were confirmed after screening against controls. The 16 compounds exhibited IC50 <10 ΜM in dose–response experiments for inhibiting the Gα: RGS17 interaction. Four exhibited IC50 values <6 ΜM while inhibiting the Gα: RGS17 interaction >50% when compared to a biotinylated GST control (TrueHits). Compounds RL–1 and RL–2 were confirmed by flow cytometry protein interaction assay (FCPIA) while RL–3 and RL–4 were unable to disrupt this PPI in FCPIA. All four compounds were tested using the differential scanning fluorimetry (DSF) method, which is based on energetic coupling between ligand binding and protein unfolding and found compounds RL–1 to RL–4 all slightly increased protein stability upon ligand binding. Chapter 4 focuses on the miniaturization and optimization of AlphaScreen® to a 1536–well format and screening of the MicroSource SPECTRUM and NDL3000 small molecule libraries. This increased throughput 11–fold and decreased our working volumes from 45 ΜL to 10 ΜL, which reduced reagent cost. After optimization, we retained in an excellent Z–factor ≥0.70 with S/N>5.77 and increased the screening rate to more than 12,000 compounds per hour. In this format, the initial screening of the SPECTRUM and NDL3000 libraries was completed and filtered the initial hits by counter screening and PAINs filtering as well as developing four powerful orthogonal assays for the characterization of potential lead molecules. Chapter 6 focuses on the future directions, which include the screening the in–house 50,000 compound library in the University of Iowa HTS Core facility as well as the development of cell based assays to determine the activity of these leads in the cellular milieu. These screens are the first step to developing novel pharmacophores for further optimization of structure with the focus on RGS17 activity in enzymatic, whole cell, xenograft and whole animal models as well as providing new avenues for the development of anticancer therapies.