The KCNE1 and KCNE3 type I transmembrane-spanning β-subunits assemble with the KCNQ1 voltage-gated K+ channel to afford membrane-embedded complexes with dramatically different properties. Assembly with KCNE1 produces the very slowly activating and deactivating IKs current that shapes the repolarization phase of cardiac action potentials. Genetic mutations in KCNQ1 or KCNE1 that reduce IKs current cause long QT syndrome and predispose affected individuals to potentially fatal cardiac arrhythmias. In contrast, complexes formed between KCNQ1 and KCNE3 produce rapidly activating and mostly voltage-independent currents, properties that are essential for function in K+ recycling and Cl−secretion in gastrointestinal epithelia. This thesis addresses how these two homologous accessory peptides impart their distinctive effects on KCNQ1 channel gating by examining two important protein regions: 1) a conserved C-terminal motif in the β-subunits themselves, and 2) the voltage sensing domain of KCNQ1 channels. Sequences in both the transmembrane domain and C-terminus of KCNE1 and KCNE3 have been identified as contributing to the divergent modulatory effects that these β-subunits exert. The homology of transmembrane-abutting C-terminal residues within the KCNE family and the presence of long QT-causing mutations in this region highlight its importance. A bipartite model of modulation was proposed that suggests the transmembrane domain of KCNE1 is passive, allowing the C-terminal domain to control modulation. Chapter II builds on this model by investigating the effect of mutating specific amino acids in the KCNE1 C-terminal domain. Point mutants that produce ‘high impact’ perturbations in gating were shown to cluster in a periodic fashion, suggesting an alpha-helical secondary structure that is kinked by a conserved proline residue and interacts with the Q1 channel complex. In Chapter III, the voltage sensing domain of Q1 channels is examined in the presence of either KCNE1 or KCNE3. To determine the influence of these two peptides on voltage sensing, the position of the S4 voltage sensor was monitored using cysteine accessibility experiments. In the slowly opening KCNQ1/KCNE1 complexes, voltage sensor activation appears to occur much faster than the onset of current, suggesting that slow channel activation is not due to slowly moving voltage sensors. KCNE3, on the other hand, shifts the voltage sensor equilibrium to favor the active state, producing open channels even at negative voltages. Taken together, these findings provide mechanistic detail to illustrate how two homologous peptides radically alter the gating properties of the same K+ channel and present a structural scaffold to map protein-protein interactions.

The body of work presented here is a compendium of the multiple steps required for an investigator initiated trial of an existing medication (Valproic Acid- VPA) for a new indication (Retinitis Pigmentosa – RP). The chapters are listed in logical and chronological order of the process. In order to access patient records an expedited Institutional Review Board (IRB) application for retrospective chart review was submitted (Chapter 1). These records enabled the statistical analysis which not only laid the framework for the trial design, but also became the basis for two manuscripts (Chapter 2). Protocol development informed by the preliminary human studies (Chapter 3) was an instrumental part of the Investigational New Drug (IND) application (Chapter 3.5). This protocol along with the extensive case report forms that detail the intended data to be collected are included in the IND application. Because the Phase II clinical trial proposed attempting to identify the specific RP mutations of the subjects utilizing a National Eye Institute (NEI) study that enabled free genotyping services, two IRB applications were submitted (Chapter 3.6). The first was for approval of the NEI genotyping protocol, the second involved the VPA intervention. Two very different sources of funding for this trial were attempted (Chapter 4) – the NIH via the Challenge Grant mechanism and a private eye disease foundation (Foundation Fighting Blindness). In Chapter 5 I detail the alternate study designs that were considered and developed for this trial (and ultimately abandoned). Finally, in Chapter 6, I formally detail my suggestions to aid in the development of a comprehensive investigator initiated core facility at UMMMC. The goal of this project was two-fold. The first was to learn the entire process of trial and protocol design both from a Umass Institutional perspective as well as from the perspective of the FDA. The second goal was the very real prospect of helping patients with a blinding disease. This work was successful on both counts. IRB approval was received for all the submitted applications. The complexity and uniqueness of many aspects of these submissions culminated in a comprehensive learning experience. The process of working with the Umass Research Pharmacy as well as developing the industry contacts and know-how to develop a workable and financially feasible placebo were both particularly important learning experiences. FDA approval of the IND submission was also received, and the process of pre-communication and delving into the considerable and ever-changing rules and regulations resulted in an extensive and valuable knowledge base. While the practicality of funding has limited the ability of this trial to move forward at this point, given the extensive framework laid by this body of work, we are actively pursuing other opportunities. The third outcome of this work, while not as intentional, was the considerable process of determining the specific competencies and infrastructure that exist at UMMMC to enable investigator initiated drug intervention studies. While this institution is clearly moving rapidly in the direction of translational research, the many needs of these studies are often only clearly understood when the process is specifically undertaken. In completing the approval of this Phase II clinical trial, I was not only able to better understand and define the existing capabilities of UMMMC for this kind of research, I was able to add to that infrastructure when the existing knowledge or skill set was not available. In this manner, I was able to inform and guide many of the support personnel who guided me and have become a part of the strategic direction of UMMMC towards clinical translational research.

Many steps go into developing a clinical viral gene therapy. The course starts with appropriate disease selection and moves through the many hurdles of in-vitro testing, animal model validation and proof-of-concept studies, all the way through pre-clinical large animal studies. In this thesis, I propose to outline the process of developing a translation pathway for a gene therapy using recombinant adeno-associated virus (rAAV). I will expand on this outline using data that I have generated during the course of my Ph.D. that ranges from animal model validation all the way through pre-clinical vector stability studies. Two disease models will be discussed throughout this thesis, Cockayne Syndrome (CS) and Alpha-1 Antitrypsin Deficiency (AATD). Cockayne Syndrome is a rare autosomal recessive genetic disorder involving mutations in either the CSA or CSB gene, leading to defects in DNA repair. Clinically this presents as progressive degeneration of the central nervous system, retina, cardiovascular system, and cochlea, which leads to mental retardation, post-natal growth defects, ocular abnormalities, and shortened life expectancy. Alpha-1 antitrypsin is a serine protease inhibitor largely produced in the liver that mainly functions to inhibit neutrophil elastase within the lung. AATD leads to an increased risk of emphysema, with shortened life expectancy, and also results in accumulations of mutant AAT polymers in the liver, sometimes leading to liver failure. Using these two disease models I will outline the upstream and downstream pre-clinical work as well as the transition to clinical trials of a rAAV based gene therapy.

Congenital Adrenal Hyperplasia (CAH) encompasses several disorders related to disruptions in the adrenal steroid production pathway. These disruptions may cause virilization of the external female sex organs, incorrect gender assignment, precocious puberty, and in the most severe form, may cause life-threatening salt wasting and adrenal crisis if not detected and treated early in the newborn period. 17α-Hydroxyprogesterone (17-OHP) is the primary target for immunofluorescence detection of CAH from dried blood spots in newborn screening (NBS). Unfortunately, current immunoassay techniques for the detection of CAH suffer from high false positive rates. The primary factors contributing to false positive determinations can include the natural increase of 17-OHP due to stress stimuli as well as cross-reactivity of the immunoassay antibody with other hormones and endogenous compounds in blood. Analysis of the adrenal steroid profile and corresponding analyte ratios using high performance liquid chromatography (HPLC)or ultra-high pressure liquid chromatography (UHPLC)combined with tandem mass spectrometry (MS/MS) has been shown to be a sensitive and selective technique for the significant reduction of the false positive reporting rate for CAH in newborn screening. In working toward optimization, validation, and implementation of an HPLC-MS/MS steroid profile for use by Virginia’s Newborn Screening laboratory as a 2nd tier analysis for CAH screening, a commercially-available core-shell HPLC column with a biphenyl stationary phase was determined to offer adequate retention and selectivity to achieve baseline resolution of isobaric target analytes under rapid reversed phase gradient conditions. Method linearity, precision, and accuracy were assessed using enriched dried blood spot materials. Double-blinded analyses of over 300 newborn dried blood spot specimens were used to determine clinical sensitivity and specificity of the assay, which is projected to substantially reduce the false positive reporting rate for CAH screening while meeting target sample turnaround times.

Purpose: The purpose of this study was to determine the usefulness of SBAR-cued web-based communication skills training and address study participants' perceptions of the training. Specific Aims: Evaluate the usefulness and accuracy of participants to answer prompts of SBAR-cued communication responses. Describe individuals' perspectives of the acceptability of using SBAR patient-HCP communication simulation to better prepare for ED visits during a SCC. Framework: This study was guided by The Theory of Self-Care Management for Sickle Cell Disease (SCMSCD). Design: A secondary analysis was conducted using a qualitative descriptive approach. Inter-rater reliability (IRR) of qualitative data was used to evaluate the usefulness and accuracy of participants to answer prompts of SBAR-cued communication responses. Content analysis was also utilized to describe individuals' perspectives of the acceptability of using SBAR patient-HCP communication simulation to better prepare for ED visits during a SCC. Results: IRR between raters ranged from 64%-94% with predominant themes of (1) Patient-Provider Communication and Interaction, (2) Patients want to be Heard and Believed, (3) Accuracy of the ED Experience and Incorporating the Uniqueness of each Patient and (4) Overall Usefulness of the Video Trainer emerging. Conclusions: This secondary analysis supported how SBAR can be effectively used to assist patients in a SCC to communicate with their HCP. Participants' responses indicated the training module facilitated communication between patients and HCPs.

Histone lysine methylation is an important epigenetic mark for regulation of gene expression and chromatin organization. Setdb1 (Set domain, bifurcate 1), one of the histone lysine methyltransferases, specifically methylates histone H3 at lysine 9 (H3K9) and participates in transcriptional repression and heterochromatin formation. The major task of my thesis work was to investigate the epigenetic roles of Setdb1 in regulating brain functions. I started my thesis work by examining Setdb1 expression pattern during mouse brain development. The most robust signal of Setdb1 was detected in the fetal brains at embryonic day 12.5, with a ubiquitous distribution in all the proliferative zones, as well as the cortical plate and other regions comprised of postmitotic neurons. The expression of Setdb1 decreased as the brain developed, and this down-regulation profile was correlated to neuronal maturation as examined in a primary culture model of mouse cortical neurons. I then generated CK-Setdb1 transgenic mice, in which a myc-tagged full length mouse Setdb1 was constantly expressed in postmitotic neurons under the control of the CaMK II alpha promoter (CK). The expression of mycSetdb1 was detected in NeuN positive cells throughout most forebrain regions including cerebral cortex, striatum and hippocampus. A sustained increase of Setdb1 in CK-Setdb1 transgenics was verified at both mRNA and protein levels. Furthermore, an increase of H3K9 trimethylation was detected at major satellite DNA repeats in CK-Setdb1forebrains, which indicated that transgene-expressed mycSetdb1 was functionally active in adult brains. The behavioral phenotype of CK-Setdb1 transgenics was examined by using two separate founder lines. Gross neurological functions including body weight, locomotion activity, motor coordination, and breeding behavior were generally normal in CK-Setdb1 mice. CK-Setdb1 mice were further subjected to behavioral paradigms related to mood and cognitive functions. Intriguingly, as compared to the littermate controls, CK-Setdb1 mice represent a lower level of depression as indicated by decreased total immobility in two different behavioral despair tests. Moreover, CK-Setdb1 mice showed an accelerated extinction in the learned helplessness paradigm after a delayed interval (7 days), indicating a faster recovery from an established status of despair. The potential confounding factors, like memory deficits, were ruled out as CK-Setdb1 mice showed normal or even improved performances in different memory-related paradigms. Anxiety scores and stimulant drug response were normal in CK-Setdb1mice. Taken together, these findings suggested that a specific antidepressant-like phenotype was elicited by the over-expression of Setdb1 in adult mice forebrains. To further study the molecular mechanism underlying Setdb1-associated antidepressant-like behavioral changes, I screened for Setdb1-binding sites in a genome-scale by ChIP-on-chip using a tiling microarray from Affymetrix. Unexpectedly, Setdb1 showed a very restricted binding profile with a high specificity towards ionotropic glutamate receptor genes including the NMDA receptor 2B subunit gene Grin2b, which is a new target for the treatment for major depression. An increase of H3K9 dimethylation at Setdb1-binding site on Grin2b locus was detected in CK-Setdb1 hippocampus, which was correlated to a decrease of Grin2b expression as well as an accelerated desensitization of NMDA receptor. Furthermore, Chromosome Conformation Capture (3C) on Grin2b locus revealed a repressive chromatin loop structure, which tethered the distal Setdb1-binding site (~ 32 Kb downstream of transcriptional start site (TSS)) to a proximal intronic region (~12 Kb downstream of TSS) that is enriched for the binding of KAP1, a well-studied Setdb1-interacting transcriptional corepressor. Taken together, our data indicated that Setdb1 repressed Grin2b expression via H3K9 hypermethylation and higher-order chromatin loop formation, which may contribute to the antidepressant-like phenotype we observed in CK-Setdb1mice. The second part of my thesis work was to investigate the role of Setdb1 in the animal model of a neurodevelopmental disorder - Rett syndrome (RTT). Loss-of-function mutations of the gene encoding methyl-CpG binding protein 2 (MECP2) is the primary cause of RTT. There is an overlap between Setdb1- and Mecp2-associated repressive chromatin machineries, which both include histone deacetylase complex, H3K9 methyltransferase, DNA methyltransferase and heterochromatin protein 1 (HP1). Moreover, in contrast to Setdb1, which is downregulated during the cortical neuronal differentiation, Mecp2 is upregulated and the expression level is positively correlated to neuronal maturation. Therefore, we hypothesized that there is a functional redundancy between Setdb1 and Mecp2, and the up-regulation of Setdb1 in mature neurons will compensate for brain deficiency due to the loss of Mecp2. To test this hypothesis, I crossed CK-Setdb1 transgenic mice with nestincre-Mecp2 conditional knockout mice (Mecp2-/y). The behavior changes of CK-Setdb1/Mecp2-/y mice, including body weight, locomotion, motor coordination, and life span, were then compared to Mecp2-/y mice. No significant improvements in behaviors or survival were observed from CK-Setdb1/Mecp2-/y mice. Because the activation of CK promoter is limited to defined population of postmitotic neurons in forebrain, I tested our hypothesis by generating another strain of Setdb1 overexpression mice – tauSetdb1, in which the expression of mycSetdb1 is under the control of an endogenous pan-neuronal active promoter Tau. However, the introduction of tauSetdb1 also failed to rescue Mecp2 deficiency. The life span of tauSetdb1/ Mecp2-/y was even shorter as compared to Mecp2-/y mice (Kaplan-Meier, p=0.07). In conclusion, up-regulation of Setdb1 in adult brain was not sufficient to rescue Mecp2deficiency in the mouse model of RTT. One of the most challenges to study neuronal dysfunctions in brain diseases is the cellular heterogeneity of central nervous system. Current techniques for chromatin studies, including chromatin immunoprecipitation (ChIP) assays, usually lack of single cell resolution and are unable to examine the neurobiological changes in defined cell populations. In the third part of my thesis work, I developed a modified protocol to isolate neuronal nuclei from brain homogenates via Fluorescence-Activated Cell Sorting (FACS). In general, total nuclei was extracted from frozen brains, neuronal nuclei were then immuno-tagged with NeuN and sorted via FACS. Besides the NeuN labeling-FACS protocol, I also generated CK-H2BeGFP transgenic mice, in which a histone H2B-eGFP (enhanced green fluorescent protein) fusion protein was expressed in the nuclei of postmitotic neurons in mouse forebrain. Nuclei extracted from CKH2BeGFP brain were directly applied for FACS sorting. By using this protocol, we routinely got around 6-8 x106neuronal nuclei from one adult mouse forebrain, which was sufficient for ChIP applications followed by single gene PCR and microarray studies. In conclusion, our protocol permits large-scale studies of chromatin modifications or any other nuclei events in defined cell populations from distinct brain regions. Taken together, my dissertation work will lead to a better understanding of the epigenetic roles of histone H3K9 methyltransferase Setdb1 in brain functions, and may provide new targets for the therapeutic treatment of major depression.

Werner syndrome (WS) is an autosomal recessive disorder associated with premature aging and cancer predisposition. WS cells show increased genomic instability and are hypersensitive to DNA-damaging agents. WS is caused by mutations of the WRN gene. WRN protein is a member of RecQ DNA helicase family. In addition to a conserved 3’–5’ helicase activity, the WRN protein contains unique 3’–5’ exonuclease activity. WRN recognizes specific DNA structures as substrates that are intermediates of DNA metabolism. WRN physically and functionally interacts with many other proteins that function in telomere maintenance, DNA replication, and DNA repair. The function of WRN is regulated by post–translational modifications that include phosphorylation, acetylation, and sumoylation. SIRT1 is a NAD-dependent histone deacetylase (HDAC) that deacetylates histones and a numbers of cellular proteins. SIRT1 regulates the functions of many proteins, which are important for apoptosis, cell proliferation, cellular metabolism, and DNA repair. SIRT1 is also regulated by other proteins or molecules from different levels to activate or inhibit its deacetylase activity. In this study, we found that SIRT1 interacts with and deacetylates WRN. We further identified the major acetylation sites at six lysine residues of the WRN protein and made a WRN acetylation mutant for functional analysis. We found that WRN acetylation increases its protein stability. Deacetylation of WRN by SIRT1 reverses this effect. CREB-binding protein (CBP) dramatically increased the half-life of wild-type WRN, while this increase was abrogated with the WRN acetylation mutant. We further found that WRN stability is regulated by the ubiquitination pathway, and that WRN acetylation by CBP dramatically reduces its ubiquitination level. We also found that acetylation of WRN decreases its helicase and exonuclease activities, and that SIRT1 reverses this effect. Acetylation of WRN alters its nuclear distribution. Down-regulation of SIRT1 increases WRN acetylation level and prevents WRN protein translocating back to nucleolus after DNA damage. Importantly, we found that WRN protein is strongly acetylated and stabilized in response to mitomycin C (MMC) treatment. H1299 cells that were stably expressing WRN acetylation mutant display significantly higher sensitivity to MMC than the cells expressing wild-type WRN. Taken together, these data demonstrated that acetylation pathway plays an important role in regulating WRN function in response to DNA damage. A model has been proposed based on our discoveries.

Recent developments in neurobiology make it clear that glia play fundamental and active roles, in the adult and in development. Many hereditary cognitive disorders have been linked to developmental defects, and in at least two cases, Rett Syndrome and Fragile X Mental Retardation, glia are important in pathogenesis. However, most studies of developmental disorders, in particular intellectual disability, focus on neuronal defects. An example is intellectual disability caused by mutations in ACSL4, a metabolic enzyme that conjugates long-chain fatty acids to Coenzyme A (CoA). Depleting ACSL4 in neurons is associated with defects in dendritic spines, a finding replicated in patient tissue, but the etiology of this disorder remains unclear. In a genetic screen to discover genes necessary for visual function, I identified the Drosophila homolog of ACSL4, Acsl, as a gene important for the magnitude of neuronal transmission, and found that it is required in glia. I determined that Acsl is required in a specific subtype of glia in the Drosophila optic lobe, and that depletion of Acsl from this population causes morphological defects. I demonstrated that Acsl is required in development, and that the phenotype can be rescued by human ACSL4. Finally, I discovered that ACSL4 is expressed in astrocytes in the mouse hippocampus. This study is highly significant for understanding glial biology and neurodevelopment. It provides information on the role of glia in development, substantiates a novel role for Acsl in glia, and advances our understanding of the potential role that glia play in the pathogenesis of intellectual disability.

Recent studies have shown elevated neuroinflammation in a large subset of individuals diagnosed with schizophrenia. A pro-inflammatory cytokine, tumor necrosis factor-alpha (TNFα), has been directly linked to this neuroinflammation. This study examined the effects of two TNFα modulators (PD2024 and PD340) produced by our collaborators at P2D Bioscience, Inc., to alleviate auditory sensorimotor gating deficits and reduce microglial cell activation present in the polyinosinic:polycytidylic (Poly I:C) rodent model of schizophrenia. Auditory sensorimotor gating was assessed using prepulse inhibition and microglial activation was examined and quantified using immunohistochemistry and confocal microscopy, respectively. Both PD2024 and PD340 alleviated auditory sensorimotor gating deficits and reduced microglia activation and thereby demonstrated the ability to treat both the behavioral and neuroinflammatory aspects of the disorder. These results are significant and suggest that neural TNFα is a potential pharmacological target for the treatment of schizophrenia.

The gut microbiota and its metabolites have vast impacts on the human digestive system, immune system, and health outcomes. Short chain volatile fatty acids (SCVFAs) present in feces can be representative of the interactions of the microbiota present in the gut. Low microbiota diversity in the human gut is highly associated with obesity and adverse health outcomes. Furthermore, the maternal microbiome has a direct impact on neonatal microbiota through various pathways such as environment, skin flora, breast milk composition, and vaginal secretions. This study is aimed to further understand the associations between various factors (maternal adiposity, gestational time, length of life, delivery mode, and race/ethnicity ) and neonatal microbiome and its metabolites, SCFA. Data (pre-pregnancy BMI, gestational time, length of life at time of sample collection, delivery mode, race/ethnicity, SCVFA profiles, fecal fermentation profiles, and 16s rRNA sequences, n=75) was obtained from 75 mother-infant dyads. Qiagen CLC Genomics Workbench was used to process 16s RNA data, generate quantitative and qualitative measures of alpha and beta diversity, and generate an analysis of the composition of microbiomes for differential abundances. Multiple metrics were analyzed for alpha and beta diversity and no significant differences were found for acetic acid (A), propionic acid (P), butyric acid (B), or APB combined. Shannon diversity index, a measure of Alpha diversity, showed no significant difference between groups in each subset. BMI differences were significant for no c-section vs. c-section and Black vs. White race/ethnicity. There were no significant differences found in PERMANOVA, a measure of beta diversity, or found in differential abundances among the groups.