Inflammation Alters Histone Methylation in the Central Nervous System: Implications for Neuropsychiatric Disease: A Dissertation

Maternal infection during pregnancy is associated with increased risk of both schizophrenia and autism in offspring. Based on this observation, the maternal immune activation mouse model was developed, in which pregnant rodents are treated with immune-activating agents and the brains and behavior of the adult offspring studied. This model has been found to recapitulate a variety of molecular, cellular, and behavioral abnormalities observed in both schizophrenia and autism. However, despite the abundant evidence provided by these studies that prenatal exposure to inflammation alters brain development and function later in life, the molecular mechanisms by which inflammation mediates these effects remains unclear. It has been suggested that other prenatal risk factors for neuropsychiatric disease may alter brain development, in part, via epigenetic mechanisms such as DNA methylation and histone modification. However, a link between inflammation and epigenetic modification in brain has not been established. Therefore, the focus of my thesis was to examine the effect of inflammation on the histone modification, trimethylated histone H3 lysine 4 (H3K4me3), which has been implicated in both normal brain development and in schizophrenia. In Chapter II, I describe experiments examining the effect of a specific, cytokine, interleukin-6 (IL-6), on H3K4me3 in rat forebrain culture. I show that IL-6 treatment results in altered levels of H3K4me3 at multiple gene promoters, frequently in conjunction with altered mRNA expression levels, and demonstrate that a subset of these alterations appear to be dependent on signaling via the signal transducer and activator of transcription 3 (Stat3) pathway. Furthermore, some of the genes affected by IL-6 also showed altered H3K4me3 levels in autism postmortem brain. Though a direct link still remains to be established, this observation suggests that epigenetic changes observed in neuropsychiatric disease may have been induced by prenatal exposure to inflammation. In Chapter III, I describe in vivo experiments employing the maternal immune activation (MIA) mouse model to examine the effects of prenatal inflammation on H3K4me3 in the brain of the offspring, at both fetal and adult stages. I found that immune activation resulted in increased levels of IL-6 protein in fetal brain, working memory deficits in the adult offspring, and subtle changes in H3K4me3 levels in fetal and adult brain. Taken together, these findings demonstrate that an environmental risk factor for schizophrenia and autism—namely, inflammation—is capable of inducing robust and widespread histone modifications in a model of the central nervous system and smaller changes in vivo. This suggests that prenatal exposure to inflammation in human populations may lead to increased susceptibility for neuropsychiatric disorders, in part, by altering chromatin modifications in developing brain

DNA methylation changes in schizophrenia and bipolar disorder

The etiology of the major psychotic disorders, including schizophrenia and bipolar disorder, remains poorly understood. Postmortem brain studies have revealed altered expression of multiple mRNAs, affecting neurotransmission, metabolism, myelination and other functions. Epigenetic mechanisms could be involved, because for a limited number of genes, the alterations of mRNA levels have been linked to inverse DNA methylation changes at sites of the corresponding promoters. However, results from independent studies have been inconsistent, and when expressed in quantitative terms, disease-related methylation changes appear to be comparatively subtle. A recent study identified approximately 100 loci with altered CpG methylation in schizophrenia or bipolar disorder, the majority of which were gender-specific. Additional work will be necessary to clarify the origin and timing of these methylation changes in psychosis and to determine the specific cell types affected in the diseased brain

A simple method for improving the specificity of anti-methyl histone antibodies

Antibodies differentiating between the mono-, di- and trimethylated forms of specific histone lysine residues are a critical tool in epigenome research, but show variable specificity, potentially limiting comparisons across studies and between samples. Using trimethyl histone H3 lysine 4 (H3K4me3)-a mark enriched at transcription start sites (TSS) of active genes-as an example, we describe how simple co-incubation with synthetic peptide of the K4me2 modification leads to increased specificity for K4me3 and a much sharper peak distribution proximal to TSS following chromatin immunoprecipitation and massively parallel sequencing (ChIP-Seq)

Setdb1 histone methyltransferase regulates mood-related behaviors and expression of the NMDA receptor subunit NR2B

Histone methyltransferases specific for the histone H3-lysine 9 residue, including Setdb1 (Set domain, bifurcated 1)/Eset/Kmt1e are associated with repressive chromatin remodeling and expressed in adult brain, but potential effects on neuronal function and behavior remain unexplored. Here, we report that transgenic mice with increased Setdb1 expression in adult forebrain neurons show antidepressant-like phenotypes in behavioral paradigms for anhedonia, despair, and learned helplessness. Chromatin immunoprecipitation in conjunction with DNA tiling arrays (ChIP-chip) revealed that genomic occupancies of neuronal Setdb1 are limited t

Clinically Relevant Drug Interactions with Monoamine Oxidase Inhibitors.

Monoamine oxidase inhibitors (MAOI) are a class of drugs that were originally developed for the treatment of depression but have since been expanded to be used in management of affective and neurological disorders, as well as stroke and aging-related neurocognitive changes. Ranging from irreversible to reversible and selective to non-selective, these drugs target the monoamine oxidase (MAO) enzyme and prevent the oxidative deamination of various monoamines and catecholamines such as serotonin and dopamine, respectively. Tyramine is a potent releaser of norepinephrine (NE) and is found in high concentrations in foods such as aged cheeses and meats. Under normal conditions, NE is unable to accumulate to toxic levels due to the presence of MAO-A, an enzyme that degrades neurotransmitters, including NE. When MAO-A is inhibited, the capacity to handle tyramine intake from the diet is significantly reduced causing the brain to be vulnerable to overstimulation of postsynaptic adrenergic receptors with as little as 8-10 mg of tyramine ingested and can result in life-threatening blood pressure elevations. In addition to adverse reactions with certain foods, both older and newer MAOIs can negatively interact with both sympathomimetic and serotonergic drugs. In general, patients on a MAOI want to avoid two types of medications: those that can elevate blood pressure via sympathomimetic actions (e.g., phenylephrine and oxymetazoline) and those that can increase serotonin levels via 5-HT reuptake inhibition (e.g., dextromethorphan, chlorpheniramine, and brompheniramine). Illicit drugs that stimulate the central nervous system such as ecstasy (MDMA, 3,4-methylenedioxymethamphetamine) act as serotonin releasers. Patient involvement is also crucial to ensure any interaction within the healthcare setting includes making other providers aware of a MAOI prescription as well as avoiding certain OTC medications that can interact adversely with MAOIs

Identifying cell enriched miRNAs in kidney injury and repair

Small noncoding RNAs, miRNAs (miRNAs), are emerging as important modulators in the pathogenesis of kidney disease, with potential as biomarkers of kidney disease onset, progression, or therapeutic efficacy. Bulk tissue small RNA-sequencing (sRNA-Seq) and microarrays are widely used to identify dysregulated miRNA expression but are limited by the lack of precision regarding the cellular origin of the miRNA. In this study, we performed cell-specific sRNA-Seq on tubular cells, endothelial cells, PDGFR-β+ cells, and macrophages isolated from injured and repairing kidneys in the murine reversible unilateral ureteric obstruction model. We devised an unbiased bioinformatics pipeline to define the miRNA enrichment within these cell populations, constructing a miRNA catalog of injury and repair. Our analysis revealed that a significant proportion of cell-specific miRNAs in healthy animals were no longer specific following injury. We then applied this knowledge of the relative cell specificity of miRNAs to deconvolute bulk miRNA expression profiles in the renal cortex in murine models and human kidney disease. Finally, we used our data-driven approach to rationally select macrophage-enriched miR-16-5p and miR-18a-5p and demonstrate that they are promising urinary biomarkers of acute kidney injury in renal transplant recipients

Biomolecular Detection employing the Interferometric Reflectance Imaging Sensor (IRIS)

The sensitive measurement of biomolecular interactions has use in many fields and industries such as basic biology and microbiology, environmental/agricultural/biodefense monitoring, nanobiotechnology, and more. For diagnostic applications, monitoring (detecting) the presence, absence, or abnormal expression of targeted proteomic or genomic biomarkers found in patient samples can be used to determine treatment approaches or therapy efficacy. In the research arena, information on molecular affinities and specificities are useful for fully characterizing the systems under investigation

A governance model for integrated primary/ secondary care for the health-reforming first world: results of a systematic review

Internationally, key health care reform elements rely on improved integration of care between the primary and secondary sectors. The objective of this systematic review is to synthesise the existing published literature on elements of current integrated primary/secondary health care. These elements and how they have supported integrated healthcare governance are presented.A systematic review of peer-reviewed literature from PubMed, MEDLINE, CINAHL, the Cochrane Library, Informit Health Collection, the Primary Health Care Research and Information Service, the Canadian Health Services Research Foundation, European Foundation for Primary Care, European Forum for Primary Care, and Europa Sinapse was undertaken for the years 2006-2012. Relevant websites were also searched for grey literature. Papers were assessed by two assessors according to agreed inclusion criteria which were published in English, between 2006-2012, studies describing an integrated primary/secondary care model, and had reported outcomes in care quality, efficiency and/or satisfaction.Twenty-one studies met the inclusion criteria. All studies evaluated the process of integrated governance and service delivery structures, rather than the effectiveness of services. They included case reports and qualitative data analyses addressing policy change, business issues and issues of clinical integration. A thematic synthesis approach organising data according to themes identified ten elements needed for integrated primary/secondary health care governance across a regional setting including: joint planning; integrated information communication technology; change management; shared clinical priorities; incentives; population focus; measurement - using data as a quality improvement tool; continuing professional development supporting joint working; patient/community engagement; and, innovation.All examples of successful primary/secondary care integration reported in the literature have focused on a combination of some, if not all, of the ten elements described in this paper, and there appears to be agreement that multiple elements are required to ensure successful and sustained integration efforts. Whilst no one model fits all systems these elements provide a focus for setting up integration initiatives which need to be flexible for adapting to local conditions and settings