Cytokine genetics and expression : implications of an immunogenetic pathogenesis in autism spectrum disorders.

Autism Spectrum Disorder (ASD) is an idiopathic pervasive neurodevelopmental disorder associated with various neuropathologies and immunological dysfunctions. Cytokines are regulatory proteins that facilitate communication between the immune and central nervous systems and mediate inflammation, immunity, and hemopoiesis. Previous literature demonstrates that cytokine expression is altered systemically and in the central nervous system of individuals diagnosed with ASD when compared to matched neurotypical controls. Here it is proposed that cytokines are crucial mediators in autism pathogenesis. The central hypothesis of this research posits that an underlying genetic susceptibility in cytokine genes is triggered by environmental exigencies (e.g., stress, infection, ultrasound, hypoxia, pollutant or chemical exposure) during prenatal development. This hypothesis proposes that the convergence of these scenarios during vulnerable periods of neurodevelopment ultimately culminates in the autism phenotype. To test whether cytokines are crucial mediators in autism pathogenesis, the DNA sequences of 22 single nucleotide polymorphisms (SNPs) within 13 cytokine genes were genotyped in a cohort of autistic patients and controls. Three SNP frequencies for both pro-inflammatory [IL1R(+1970)] and anti-inflammatory [IL4(-590) and IL4(-33)] cytokine genes were found to be significantly associated with autism incidence. Next, cytokine mRNA profiles were investigated in post-mortem cortical tissue of eight autistic subjects and eight matched controls. Transcriptional profiling of cytokine genes in five post-mortem cortical regions corresponding to Brodmann Areas 4, 9, 17, 22 and 46 indicated heterogeneous expression of cytokine (TNF-a, IL-6, TGFß-l, IL-1ß) and chemokine (IL-8) transcripts in autistic subjects, but these alterations did not reach statistical significance or reflect values of cortical cytokine translational patterns established in previous literature. Finally, it was shown that systemic cytokine translational expression in the blood plasma of children diagnosed with autism disorder was not modulated with intravenous glutathione administration. These findings indicate that cytokines play an important role in ASD pathogenesis and reveal possible molecular mechanisms that warrant future investigation in etiological research. They also show that the antioxidant agent glutathione, which ostensibly alters cytokine expression at the intracellular level, does not affect systemic cytokine expression or ameliorate behavioral outcome when administered exogenously

Activation of the pro-resolving receptor Fpr2 attenuates inflammatory microglial activation

Poster number: P-T099 Theme: Neurodegenerative disorders & ageing Activation of the pro-resolving receptor Fpr2 reverses inflammatory microglial activation Authors: Edward S Wickstead - Life Science & Technology University of Westminster/Queen Mary University of London Inflammation is a major contributor to many neurodegenerative disease (Heneka et al. 2015). Microglia, as the resident immune cells of the brain and spinal cord, provide the first line of immunological defence, but can become deleterious when chronically activated, triggering extensive neuronal damage (Cunningham, 2013). Dampening or even reversing this activation may provide neuronal protection against chronic inflammatory damage. The aim of this study was to determine whether lipopolysaccharide (LPS)-induced inflammation could be abrogated through activation of the receptor Fpr2, known to play an important role in peripheral inflammatory resolution. Immortalised murine microglia (BV2 cell line) were stimulated with LPS (50ng/ml) for 1 hour prior to the treatment with one of two Fpr2 ligands, either Cpd43 or Quin-C1 (both 100nM), and production of nitric oxide (NO), tumour necrosis factor alpha (TNFα) and interleukin-10 (IL-10) were monitored after 24h and 48h. Treatment with either Fpr2 ligand significantly suppressed LPS-induced production of NO or TNFα after both 24h and 48h exposure, moreover Fpr2 ligand treatment significantly enhanced production of IL-10 48h post-LPS treatment. As we have previously shown Fpr2 to be coupled to a number of intracellular signaling pathways (Cooray et al. 2013), we investigated potential signaling responses. Western blot analysis revealed no activation of ERK1/2, but identified a rapid and potent activation of p38 MAP kinase in BV2 microglia following stimulation with Fpr2 ligands. Together, these data indicate the possibility of exploiting immunomodulatory strategies for the treatment of neurological diseases, and highlight in particular the important potential of resolution mechanisms as novel therapeutic targets in neuroinflammation. References Cooray SN et al. (2013). Proc Natl Acad Sci U S A 110: 18232-7. Cunningham C (2013). Glia 61: 71-90. Heneka MT et al. (2015). Lancet Neurol 14: 388-40

Neurobiological mechanisms of hallucinations in schizophrenia

All perception is a construct of the brain. Yet occasionally, sensory constructions emerge without origin in the physical world and are experienced as hallucinations. Hallucinations occur transdiagnostically, cross-culturally, and in all sensory modalities. They are common in people with schizophrenia, presenting in 60-80% of patients. Despite over 20 years of active neuroimaging research on hallucinations, the neural systems supporting these anomalous perceptual experiences remain disputed. This dissertation investigates the neurobiology of hallucinations, integrating research across structural and functional magnetic resonance imaging (MRI) to elucidate how hallucinations, chiefly in the context of schizophrenia, are supported by the brain, drawing on MRI indices of neurodevelopment. I introduce the phenomenon of hallucinations and motivate the utility of MRI for studying hallucinations. Considering their prevalence in other medical conditions, I conduct a meta-analysis and systematic review of the structural brain basis of hallucinations across diagnoses, primarily schizophrenia spectrum disorders and Parkinson’s disease. This illustrated distinct neuroanatomical organizations of grey matter associated with hallucinations that occur in neurodevelopmental compared to neurodegenerative disorders, which I hypothesise constitute at least two distinct mechanisms. Focussing on the neurodevelopmental mechanism characterized by fronto-temporal and insular grey matter reductions, I turn to the contribution of cortical sulcation, a product of second and third trimester neurodevelopmental processes, which has been robustly implicated in schizophrenia pathology, and, more recently, in hallucinations. Sulcal patterns derived from structural MRI provide a proxy in adulthood for early brain development. I studied two independent datasets of patients with schizophrenia who underwent clinical assessment and 3T MRI from the United Kingdom and Shanghai, China, stratified into those with and without hallucinations, and healthy controls from Shanghai. I first replicate the finding that left hemisphere paracingulate sulcus (PCS) length is reduced in patients who experience hallucinations, then demonstrate similar associations for superior temporal sulcus depth. Length and depth alterations occurred with focal deviations in sulcal geometry. The interindividual and interhemispheric variability of the PCS necessitated the development of semi-automated methods to characterize its morphology and validation to a manual protocol. I used structural covariance networks of the local gyrification index to investigate how specific sulcal deviations relate to global neurodevelopmental coordination, demonstrating that hallucinations correspond to increased covariance within and between salience and auditory networks. Hypothesizing structure-function relationships, I analyse resting-state functional MRI data from the same datasets described, finding significant interactions between PCS length and hallucinations status, but no main effects. There were no effects of hallucination status on salience and auditory network connectivity or in graph theoretical measures of connectivity, suggesting that resting-state connectivity is not a trait marker for hallucinations. Together, the discovery of neurodevelopmental alterations contributing to hallucinations provides mechanistic insight into the pathological consequences of prenatal origins. The interaction of sulcal alterations and hallucination status are associated with connectivity, which may have a role in the pathophysiology of hallucinations. I provide clear predictions and recommendations for future research.Gates Cambridge Scholarshi

Evaluating the Therapeutic Effect of an Hsp90 Inhibitor in Mouse Models of Alzheimer’s Disease

The excessive accumulation of amyloid peptides (Aβ) represents one major pathological hallmark of Alzheimer’s disease (AD), which is most notably characterized by synaptic dysfunction. Strategies targeting heat shock protein 90 (Hsp90) inhibition have been widely investigated in the treatment of cancer for over two decades. Its application in the treatment of neurodegenerative diseases however, has emerged more recently in the last decade. The role of the Hsp90 chaperone in clearing misfolded protein aggregates has been well established (in vitro only), but its function in synaptic activity remains elusive. In our study, we utilized a widely used Hsp90 inhibitor, 17-AAG (17-allylamino-17- desmethoxygeldanamycin), to show that 17-AAG not only induces a heat shock-like response, but also regulates (likely at the transcriptional level as modeled by qRT-PCR) select proteins enriched in the synapse, such as Post-synaptic density 95 (PSD95), synapsin I, and brain-derived neurotrophic factor (BDNF), among others. Confocal imaging demonstrated rescued dendritic spines with 17-AAG treatment after Aβ challenge in neuronal culture models. The functionality of these changes in the synapse was further confirmed by memory improvement in contextual fear conditioning tests. This work implied a potential strategy in using Hsp90 inhibitors to treat AD. Nevertheless, it must be noted that 17-AAG has limited feasibility in therapy due to its poor CNS-permeability. In order to test the hypothesis inspired and encouraged by the initial 17-AAG experimental results, we instead used a similar compound with favorable CNS-permeability. OS47720, a radicicol derivative Hsp90 inhibitor, produced comparable effects to those of 17- AAG in inducing heat shock-like responses and promoting synaptic protein expression. Electrophysiology studies on coherence demonstrated enhancement of neuronal activity within the cortical hippocampal network. Most importantly, chronic 0S47720 administration for three months and six months in early and middle symptomatic AD mouse model (Tg2576) both rescued memory deficits without obvious systemic toxicity. OS47720, as an Hsp90 inhibitor, was the first reported compound to display therapeutic effects after long-term treatment in an AD animal model. Post-mortem studies revealed elevation in protein expression of heat shock proteins, synaptic proteins, and BDNF following treatment, without affecting Aβ load and neuroinflammation. Downregulation of heat shock factor 1 (HSF1) by either a pharmacological inhibitor or a virus-delivered shRNA abolished OS47720’s effects on memory improvement against Aβ toxicity. Overexpressing HSF1 partially improved memory. Together with the notion that HSF1-regulated BDNF mRNA, this implicated an HSF1-mediated mechanism at the transcriptional level of synaptic genes. Importantly, these observable effects bypassed several important signaling pathways, including the survival Protein kinase B (PKB or AKT) pathway which is an underlying mechanism of most neuroprotective drugs. These findings revealed a novel function of Hsp90 inhibition in regulating synaptic gene expression and synaptic activity, further supporting the potential of using Hsp90 inhibitors in treating neurodegenerative diseases such as AD

Developing metabolomics for a systems biology approach to understand Parkinson's disease

Neurodegenerative diseases, including Parkinson’s disease (PD), are increasing in prevalence due to the aging population. Despite extensive study, these diseases are still not fully understood and the lack of personalised treatment options that can target the cause of the diseases, rather than the symptoms, has led to a greater demand for improved disease understanding, therapies and diagnostic procedures. In this thesis, we use systems biology approaches to construct disease-specific models intended for biomarker discovery, therapeutic treatment strategy identification and drug repurposing in PD. Systems biology is a mathematical field of research that analyses biological systems via construction of a computational model using experimental data. This is achieved by integration of omics data, including genomics, proteomics, transcriptomics and metabolomics. A specific approach used to identify the physico- and biochemical bounds within a biological system is constraint-based modelling, which requires the input of absolute quantitative metabolomics data. To improve our absolute quantitative coverage of the metabolome, we developed and improved new quantitative metabolomics methods using a targeted mass spectrometry workflow to obtain data intended to be integrated into constraint-based metabolic models for the study of PD. The research was financially supported by the SysMedPD project, which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 668738.Analytical BioScience

Brain structure and function in Huntington's disease gene carriers far from predicted disease onset

Whilst there are currently no available disease modifying therapies for Huntington’s Disease (HD), recent progress in huntingtin-lowering strategies hold great promise. Initiating therapies early in the disease course will be important and a complete characterisation of the premanifest period will help inform when to initiate disease modifying therapies and the biomarkers that may be useful in such trials. Previous research has characterised the premanifest period up to approximately 15 years from predicted onset, but even at this early stage the disease process is already underway as evidenced by striatal and white matter atrophy, reductions in structural connectivity within brain networks, rising biofluid biomarkers of neuronal dysfunction, elevations in psychiatric symptoms and emerging subtle cognitive impairments. In order to understand how early neurodegeneration can be detected and which measures are most sensitive to the early disease processes, we need to look even earlier in the disease course. This thesis documents the recruitment and analysis of the HD Young Adult Study: a premanifest cohort further from predicted clinical onset than previously studied with an average of 24 years prior to predicted onset. Differences between gene carriers and controls were examined across a range of imaging, cognitive, neuropsychiatric and biofluid measures. The structural and functional brain connectivity in this cohort is then investigated in further detail. By providing a detailed characterisation of brain structure and function in the early premanifest period along with the most sensitive biomarkers at this stage, this work will inform future treatment strategies that may seek to delay the onset of functional impairments in HD

Senescence

The book "Senescence" is aimed to describe all the phenomena related to aging and senescence of all forms of life on Earth, i.e. plants, animals and the human beings. The book contains 36 carefully reviewed chapters written by different authors, aiming to describe the aging and senescent changes of living creatures, i.e. plants and animals