CXCR4 is a chemokine receptor that has been linked to several disease related pathways including: HIV-1 proliferation, autoimmune disorders, inflammatory disease and cancer metastasis. The interaction of the C-X-C chemokine receptor type 4 (CXCR4) with C-X-C chemokine ligand 12 (CXCL12) plays a key role in triggering these disease related pathways. Various antagonists for these receptors have been synthesized and tested, but many are not useful clinically either because of toxicity or poor pharmacokinetics. Some of the most extensive CXCR4 antagonist libraries stem from a class of compounds, p-xylyl-enediamines, which all feature a benzene ring as the core of the compound. This work focuses on the design and synthesis of a new class of compounds that show potential as CXCR4 antagonists by using heterocyclic aromatic rings (2,6-pyridine, 2,5-furan, 2,5-pyrazine and 3,4-thiophene) as the core of the scaffold. After synthesis, these analogues were probed through a variety of assays and techniques by our collaborators in the Shim lab at Emory University including: preliminary binding assays, Matrigel invasion assays, carrageenan mouse paw edema tests, and in silico analysis. In silico analysis also probed 2,5-thiophene-based analogues previously synthesized. This work has produced the beginnings of a new library of CXCR4 antagonists and has identified fifteen hit compounds that are promising leads for further testing and modification.

Cerebral ischaemia, or stroke, is a leading cause of death and disability worldwide. Ischaemic stroke, as a result of arterial occlusion, and subarachnoid haemorrhage (SAH), as a consequence of arterial rupture in the subarachnoid space, are major subtypes of stroke. Treatment options for both are limited, and many therapeutic strategies have failed. In ischaemic stroke, lack of evidence of brain penetration of treatments has been cited as a major weakness and contributing factor to failed clinical trials. In SAH, animal models do not always mimic key pathophysiological hallmarks of the disease, hindering development of new therapeutics. Inflammation is strongly associated with brain injury after cerebral ischaemia and inhibition of the pro-inflammatory cytokine interleukin-1 (IL-1) represents apossible therapeutic target. Therefore, the key objectives of this thesis were; (1) to improve preclinical data on a promising stroke treatment, interleukin-1 receptor antagonist (IL-1Ra), by investigating its pharmacokinetic profile and brain penetration in a rat model of ischaemic stroke, (2) to investigate the endovascular perforation model of SAH in rat, as a tool for the investigation of neuroprotectants, and (3) to examine the role of the inflammatory response in the SAH model and the effects of IL-1Ra. The neuroprotective effect, pharmacokinetic profile and brain penetration of IL-1Ra were assessed after a single subcutaneous (s.c.) dose (100mg/kg) in rats, after transient (90 min) middle cerebral artery occlusion (MCAo). A single s.c. dose of IL-1Ra reduced neuronal damage, resulted in sustained, high concentrations of IL-1Ra in plasma and cerebrospinal fluid and also penetrated brain tissue exclusively in areas of blood brain-barrier (BBB) breakdown. An endovascular perforation model of SAH in rat was investigated and produced widespread multifocal infarcts. In this model, administration of IL-1Ra (s.c.) reduced BBB breakdown, which correlated with injury at 48 h. IL-1_ was expressed in the brain early after SAH in areas associated with haem oxygenase-1 (HO-1) expression, indicating the presence of free haem. Stimulation of primary mouse mixed glial cells in vitro with haem induced expression and release of IL-1 alpha but not IL-1 beta. These data, after MCAo in rat, are the first to show that a single s.c. dose of IL-1Ra rapidly reaches salvageable brain tissue and is neuroprotective. This allows confidence that IL-1Ra is able to confer its protective actions both peripherally and centrally. After experimental SAH, we suggest that haem, a breakdown product of haemoglobin, released from lysed red blood cells in the subarachnoid space, acts as a danger associated molecular pattern (DAMP) driving IL-1- dependent inflammation. These data provide new insights into inflammation after SAH-induced brain injury and suggest IL-1Ra as a candidate treatment for the disease. Overall, these findings strengthen preclinical data supporting IL-1Ra as a neuroprotective therapy for ischaemic stroke, and identify SAH as a new indication for treatment with IL-1Ra.

There has been accumulating scientific evidence, over the last three decades, of the role of inflammatory processes in the development of Alzheimer's disease (AD). Population based studies suggest that plasma levels of inflammatory markers are raised in peripheral blood of people with AD. People on long term use of non-steroidal anti-inflammatory drugs have a lower prevalence of AD. Moreover, both animal and human histopathology studies have reported localization of inflammation in brain areas primarily affected by AD pathology. Areas of increased inflammation can be visualized in vivo by Positron Emission Tomography (PET) scans using the PK11195 ligand that binds with the benzodiazepine receptor sites of activated microglial cells. Cognitive decline in AD has been shown to correlate with levels of microglial activation using PK11195 PET scans. People with amnestic mild cognitive impairment (MCI) are known to be at high risk of developing AD.We aimed to investigate the association between peripheral and central markers of inflammation and cognitive decline in a group of people with amnestic MCI.MCI subjects (n=70) underwent cognitive testing, IL-6 and CRP in peripheral blood were measured and repeated after 1 year. A sub group (n=15) was followed up for another year and central brain microglial activation was measured by PET using PK11195 along with cognitive and peripheral inflammatory marker measurement. The mean CRP and IL-6 levels of the cohort increased over one year but the rise was only significant for CRP. No association was detected between inflammatory markers levels and cognition as measured by a battery of cognitive instruments. Group comparisons of the PET cohort with healthy controls (n=5) showed increased PK11195 binding (mean binding potential) in frontal lobe, temporal lobe, parietal lobe, putamen, occipital lobes and significantly increased binding in posterior cingulate gyrus. This study, to our knowledge, is unique in studying makers of inflammation in amnestic MCI participants both in peripheral blood and brain. The results of this study, in the light of current literature, add to the importance of recognition of inflammatory processes in people at risk of developing AD. The results suggest that CRP levels rise significantly over time and are detectable in peripheral blood by using practically simple laboratory techniques. The results also suggest that activated microglia in amnestic MCI patients can be visualized in vivo by using PK11195 PET scans and show higher levels of activation as compared to healthy controls. These finding could be useful in identifying people with malactivated (pro-inflammatory) microglia as potential targets for prevention/early treatment strategies. Further studies with larger samples sizes and long term follow-up are needed to investigate whether these peripheral and central inflammatory markers could shed light on the aetiology of AD and be useful in monitoring disease progression.

Heart failure patients have dysfunction of the cardiac conduction system that contributes to a high burden of arrhythmias including atrial fibrillation and sudden cardiac death. Heart failure has been associated with the inflammatory response, but it is unknown if inflammation is playing a role in the remodelling of the cardiac conduction system in heart failure. Inflammation has been shown to be present in the myocardium from failing hearts and it is known to have detrimental effects on cardiac function, inducing fibrosis, remodelling of ion channels and even arrhythmias. However, the effect of inflammation on the cardiac conduction system has not been investigated. The aims of this study were to determine if there is an increase of pro-inflammatory cytokines and inflammatory cells in the cardiac conduction system in heart failure. In addition, to identify if there is possible inflammation-associated fibrosis and apoptosis in the cardiac conduction system in heart failure. To test these aims, three models of heart failure were used: a rat model of pulmonary arterial hypertension, a rabbit model of congestive heart failure and a rat model of myocardial infarction. In the rat model of pulmonary arterial hypertension there was a bradycardia, a prolongation of the QT interval, and an increase in the atrioventricular and ventricular refractory periods, suggesting electrical remodelling in these animals. The rats with pulmonary arterial hypertension displayed an increase in pro-inflammatory cytokines such as interleukins 1β and TGFβ in the right side of the heart, including the sinoatrial node and right Purkinje fibres of the cardiac conduction system. In addition, in these areas, there was an increase in components of the extracellular matrix, including fibronectin, collagen I and vimentin. Histology revealed regions of non-myocyte nuclei, only in the right ventricle of the rats with pulmonary arterial hypertension. Immunohistochemistry demonstrated patches of CD68 and vimentin expression (markers for macrophages and fibroblasts, respectively) in the right side of the heart in these animals. TUNEL staining also revealed an increase in apoptosis in the right side of the heart. In the rabbit model of congestive heart failure, the region most affected by inflammation was the right atrium, while few changes were measured in the ventricles or cardiac conduction system. Although these results are surprising, it is suggested that the atria could be more sensitive to the physical stretch produced in this model. In the rat model of myocardial infarction, there were regions of non-myocyte nuclei in the border zone. This region also had increases in pro-inflammatory and fibrosis markers. In conclusion, this work has presented the novel finding that there can be inflammation in the cardiac conduction system in heart failure. This could be contributing to the arrhythmias seen in heart failure patients. This could possibly lead the way to anti-inflammatories as a possible novel therapeutic for heart failure patients.

Intracerebral Haemorrhage (ICH) exhibits the worst mortality and morbidity of any stroke subtype. There are no efficacious treatments for this condition and little improvement in patient outcome has been noted despite advancements in medical science over the previous three decades. Furthermore, current available data is increasingly obsolete as the population suffering the disease burden rapidly ages and develops co-morbidities. It is thought that future therapies for this condition may be able to target neuroinflammatory response triggered by the formation of brain haemorrhage however there is little published evidence that has examined this aspect of ICH pathophysiology. This study therefore examines the current prognosis of a large cohort of patients with ICH to determine the key factors which result in mortality. We find that patients treated at a specialist centre have a surprising and significantly improved survival advantage. Since clinical practice in the United Kindgom is widely influential, the second part of the study focuses on whether the optimal cases are currently being transferred to these centres. The next part of the study then uses MRI/PET brain imaging for the first time in patients with ICH to establish an important link between the processes of neuroinflammation and Blood-Brain-Barrier breakdown. Finally, the concluding part of the thesis presents functional and radiological data from a rat model of ICH in which the inflammatory cascade has been modulated by the use of an antagonist against IL-1. The thesis thus presents a novel and important contribution in our present understanding of the preclinical and clinical disease process.

Neuroinflammation is a major feature of most neurodegenerative conditions, and can leadto the exacerbation of neuronal injury. Inflammatory challenges in the central nervoussystem (CNS) have been shown to activate peripheral immune cells, which subsequentlyinfiltrate into the brain. Concurrently, resident inflammatory cells in the CNS, such asmicroglia, become activated and release inflammatory mediators, including cytokines.The pro-inflammatory cytokine interleukin-1 (IL-1) is a key mediator of neuronal injury.Although two IL-1 agonists exist, IL-1α and IL-1β, the majority of research has focussedon the contribution of IL-1β to neuronal injury. Excitotoxic cell death in the rat brain,induced by striatal injection of the glutamate agonist AMPA, is exacerbated by coadministrationof recombinant IL-1β. To identify possible mediators which facilitate theexacerbation of neuronal injury by IL-1 this study investigated the early peripheral andcentral mediators of inflammation in response to AMPA + IL-1β.Neutrophil infiltration and increased neuronal activity were found to be present at 4h post-AMPA + IL-1β injection, which lead to the induction of microglial IL-1α in the ipsilateralcortex, in the absence of any IL-1β expression. To target the peripheral neutrophil responsean intervention study was performed to inhibit peripheral TNFα, which is thought tomobilise neutrophils. No significant effect of pre-treatment with etanercept, a TNFαinhibitor, was observed on neuronal injury produced in response to AMPA + IL-1β, thougha slight trend for protection was seen. To target the central IL-1α response after AMPA +IL-1β treatment an anti-IL-1α antibody was injected directly into the cerebral cortex, butthis had no effect on AMPA + IL-1β induced cell death. Therefore, using a reductionist invitro approach in organotypic slice cultures haemin, an inducer of endogenous IL-1α, wasused to investigate IL-1α mediated cell death. Haemin induced cell death was shown to beIL-1 dependent and preliminary studies using IL-1αKO mice indicated that IL-1α maypartially mediate this effect. This suggests that in the AMPA + IL-1β paradigm IL-1α is thedominant IL-1 isoform early after AMPA + IL-1β treatment, which can trigger subsequentneuronal cell death, as a result of the additive effects of neutrophil infiltration and highneuronal activity in the cortex. This study highlights the potential therapeutic value ofinhibiting IL-1α expression early following acute neuronal injury.

Inflammation status has been associated with chronic diseases such as Type 2 Diabetes, cardiovascular disease and cancer. Previous studies suggested that healthful dietary patterns and dietary scores may have been associated with reduced concentrations of inflammatory biomarkers. However, studies have been usually conducted among middle- aged and older adults by examining commonly used biomarkers such as C-Reactive Protein (CRP) and Interleukin 6 (IL-6). For the current study, diet quality was measured by applying food frequency data to create the 2010 Dietary Guidelines for Americans Adherence Index (DGAI-2010). Concentrations of inflammatory biomarkers were obtained from fasting blood samples collected at the late-luteal phase of paticipants’ menstrual cycle. We used linear regression to analyze the association between each natural log-transformed inflammatory biomarker concentration and the continuous DGAI-2010 Score among 142 young, healthy women (aged 18-30 years) from the UMass Vitamin D Status Study. We found that as diet quality increased, concentrations of IL-7, IL-12p70, IL-13 and IFN- were significantly lower after adjustment for BMI, age, physical activity, smoking, race/ethnicity, multivitamin use, oral contraceptive use, and total energy intake per day. Following a diet that adheres to the Dietary Guidelines for Americans as a measure of dietary quality is associated with lower inflammation in healthy, normal weight and overweight young women.

<p>Systemic inflammation is one potential mechanism underlying the depression to cardiovascular disease (CVD) relationship. In addition, somatic rather than cognitive/affective symptoms of depression may be more predictive of poorer CVD outcomes due to systemic inflammation. However, the small existing literature in this area has yielded mixed results. Therefore, the present study aimed to examine longitudinal associations between depressive symptom clusters and inflammatory biomarkers implicated in CVD (i.e., interleukin-6, IL-6; and C-reactive protein, CRP) using data from the eIMPACT trial.<b> </b>In addition, race was examined as a moderator given findings from two previous studies. </p> <p>The eIMPACT trial was a phase II, single-center randomized controlled trial comparing 12 months of the eIMPACT intervention to usual primary care for depression. Participants were 216 primary care patients aged ≥ 50 years with a depressive disorder and CVD risk factors but no clinical CVD from a safety net healthcare system (<i>M_age</i> = 58.7 years, 78% female, 50% Black, <i>M</i><i>_education</i> = 12.8 years). Depressive symptoms clusters (i.e., somatic and cognitive/affective clusters) were assessed using the Patient Health Questionnaire-9 (PHQ-9). IL-6 and high-sensitivity CRP were assessed by the local clinical research laboratory using R&D Systems ELISA kits. Change variables were modeled in MPlus using a latent difference score approach. </p> <p>The results of this study were largely null. Very few associations between depressive symptom clusters and inflammatory biomarkers implicated in CVD were observed, and the detected relationships may be due to type I error. Similarly, only one association was observed for race as a moderator, and the detected relationship may be due to type I error. The present findings do not provide strong support for the longitudinal associations between depressive symptom clusters and inflammatory biomarkers implicated in CVD nor the moderating effects of race. However, the present findings do not rule out the possibility of these relationships given important study limitations, such as study design and power. Future prospective cohort studies with multiple waves of data collection are needed to determine the longitudinal associations between depression facets and various inflammatory biomarkers implicated in CVD. In addition, a biologically-based approach to identifying facets of depression – e.g., the endophenotype model – may provide a clearer understanding of the depression-inflammation relationship.</p>

Following the TLR-dependent initiation phase of acute systemic proinflammatory responses such as sepsis, an adaptive phase represses or activates a specific pattern of gene expression until the inflammation resolves. Here, we used the THP-1 sepsis cell model of bacterial LPS/endotoxin tolerance to show that TLR4- induced miR-146a supports the feed-forward adaptive processes that silence transcription and disrupt translation of acute proinflammatory genes. First, we found that miR-146a regulates a pathway that promotes the binding of transcription repressor RelB to the TNF-α promoter, a step known to precede histone and DNA modifications, which generate facultative heterochromatin to silence acute proinflammatory genes. However, once RelB binding occurred, miR-146a inhibition could not reverse compacted chromatin, and endotoxin tolerance persisted. Second, we observed that miR- 146a regulates a pathway that supports assembly of the translation repressor complex of TNF-α by preventing the interaction of the RNA-binding protein effector Ago2 and RBM4. We also determined that once endotoxin tolerance is established, and specific genes have been reprogrammed, transcription and translation disruption can be reversed only by simultaneously depleting RelB and inhibiting miR-146a. Thus, miR-146a induction supports the TLR4-dependent shift from initiation to gene-specific repression at two levels. Our results also imply that therapies designed to reverse endotoxin tolerance as potential therapies for sepsis should be directed at the transcription and translation pathways of reprogramming.

Evidence from many recent studies has linked uncontrolled inflammatory processes to aging and aging-related diseases. Decreased a nuclear receptor subfamily of transcription factors, peroxisome proliferator-activated receptors (PPARs) activity is closely associated with increased levels of inflammatory mediators during the aging process. The anti-inflammatory action of PPARs is substantiated by both in vitro and in vivo studies that signify the importance of PPARs as major players in the pathogenesis of many inflammatory diseases. In this review, we highlight the molecular mechanisms and roles of PPARα, γ in regulation of age-related inflammation. By understanding these current findings of PPARs, we open up the possibility of developing new therapeutic agents that modulate these nuclear receptors to control various inflammatory diseases such as atherosclerosis, vascular diseases, Alzheimer's disease, and cancer.