• Rab4acontrol over metabolism and mTOR drives disease progression in Systemic Lupus Erythematosus

      Perl, Andras; Huang, Nick (2020-05-15)
      Endosomal trafficking is key to intercellular communication and metabolic regulation of immunological development. Rab4a, an endosomal trafficker, is elevated in lupus T cells and polymorphisms of the Rab4a gene have been linked to disease susceptibility. Here, we report the constitutive activation of Rab4a increases susceptibility and severity to lupus nephritis in the genetic SLE1.2.3. model of lupus and is corrected by the deletion of Rab4a in T cells. Alternatively, in a pristane model of induced autoimmunity, the deletion of Rab4a in T cells magnifies the pulmonary manifestations of diffuse alveolar hemorrhage that is otherwise protected by the constitutive activation of Rab4a. Rab4a mediates these changes through control over mTOR, mitochondrial function and homeostasis, and immunological development. In particular, inactivation of Rab4a in T cells reduces expression of activation signals, mitochondrial mass and electrochemical potential. Alterations to Rab4a activity drives the aberrant development and function of anti-inflammatory regulatory T cells and pro-inflammatory double-negative T cells. These data provide new insights into the regulation of metabolism and immunological development through endosomal trafficking. As such, the targeting of Rab4a is a novel therapeutic approach in the treatment of autoimmune diseases such as lupus, which has lacked new targeted therapeutics for more than half a century.
    • RASD2, MYH9, and CACNG2 Genes at Chromosome 22q12 Associated with the Subgroup of Schizophrenia with Non-Deficit in Sustained Attention and Executive Function

      Liu, Yu-Li; Fann, Cathy Shen-Jang; Liu, Chih-Min; Chen, Wei J.; Wu, Jer-Yuarn; Hung, Shuen-Iu; Chen, Chun-Houh; Jou, Yuh-Shan; Liu, Shi-Kai; Hwang, Tzung-Jeng; et al. (Elsevier BV, 2008-11)
      Background: In a previous linkage study of schizophrenia that included Taiwanese samples, the marker D22S278 (22q12.3) was significantly linked to schizophrenia (p .001). Methods: We conducted fine mapping of the implicated genomic region, with 47 validated single nucleotide polymorphism (SNP) markers around 1 Mb of D22S278, in a Taiwanese sample of 218 pedigrees with at least 2 siblings affected with schizophrenia. We examined the association of these SNPs and their haplotypes with schizophrenia and with subgroups defined by the presence and absence of deficits in sustained attention as assessed by undegraded and degraded continuous performance tests (CPTs). We also examined subgroups defined by deficits in categories achieved in the Wisconsin Card Sort Test (WCST). Results: Three of five candidate vulnerability genes (RASD2, APOL5, MYH9, EIF3S7, and CACNG2), which had marginally significant associations with schizophrenia, had significant associations with schizophrenic patients who did not have deficits in sustained attention on the undegraded CPT (RASD2 gene SNP rs736212; p .0008 with single locus analysis) and the degraded CPT (MYH9 gene haplotype 1-1-1-1 of SNP rs3752463 - rs1557540 - rs713839 - rs739097; p .0059 with haplotype analysis). We also found a significant association for patients who showed no deficits in executive function as measured by categories achieved in the WCST (CACNG2 gene haplotype 2-1-1-1 of SNP rs2267360 - rs140526 - rs1883987 - rs916269; p .0163 with haplotype analysis). Conclusions: The genes RASD2, MYH9, and CACNG2 might be vulnerability genes for neuropsychologically defined subgroups of schizophrenic patients.
    • Rational Design of Protein-Based Biosensors Using Engineered Binding-Induced Conformational Switches

      Loh, Stewart; ZHENG, HUIMEI (2014)
      Biosensor development continues to be driven by the growing need to accurately detect and monitor analytes with many biotechnology, clinical, agriculture, and military applications. With their well-established capacity for molecular recognition, proteins are the go-to choice of binding elements in many conventional sensor designs. Switchable proteins offer the potential of integrating analyte binding and signal transduction within a single molecule, thus reducing the need for complex and expensive detection equipment and opening the door to miniaturization and in vivo applications. The principal challenge is that the majority of natural binding proteins do not undergo a large-scale change in conformation upon target binding. This work describes two complementary protein design strategies for the rational conversion of ordinary binding proteins into ligand induced conformational switches for biosensing purposes. In the first approach, we applied the Alternate Frame Folding (AFF) mechanism to the human sulfiredoxin (hSrx) and the fibronectin (FN3) monobody scaffold towards the creation of an ATP biosensor and a customizable biosensor platform, respectively. In a second novel approach, the Protein Fragment Exchange (FREX) mechanism was demonstrated in a proof-of principle study that converts the FN3 scaffold into a biosensor, capable of genetic encoding and application in mammalian cells. While these designs were based on well established principles of protein folding and thermodynamics, the results obtained from these studies also offer important insights regarding protein sequence-structure-function relationships.
    • Reading from an Electronic Reading Device versus Hardcopy Text

      Hue, Jennifer E. (2013-06-24)
      The use of electronic reading devices has become more prevalent. Many individuals of all ages are using personal electronic readers (e.g., Kindle, Nook, E-Reader) in place of hardcopy printed materials. Previous work in our laboratory has demonstrated that symptoms when reading from a computer screen are significantly greater than those experienced when reading printed text. Accordingly, the aim of the present study was to examine both symptoms and task performance when reading from a Kindle e-reading device, and to compare the findings with those from hardcopy, printed materials.
    • Reconstitution and Characterization of RNA Polymerase I Upstream Activating Factor.

      Knutson, Bruce; Smith, Marissa (2018)
      RNA polymerase I (Pol I) transcription of the ribosomal DNA (rDNA) is the first and one of the most critical steps in ribosome biosynthesis. Pol I transcription initiation is coordinated by four Pol I factors that include the Upstream Activating Factor (UAF), TATA-binding protein (TBP), Core Factor (CF), and Rrn3. These factors work together to recruit Pol I to the rDNApromoter and to initiate transcription.UAF is a six-subunit complex composed of Rrn9, Rrn5, Uaf30, Rrn10, and histones H3 and H4.To investigate the importance of each UAF subunit in UAF complex formation and complex integrity, we developed a recombinant Escherichia coli-based system to coexpress and purify transcriptionally active UAF complex. Here, we found that no single subunit is required for UAF assembly, including histones H3 and H4. We also demonstrate that histone H3 is able to interact with each UAF-specific subunit. Last, wedetermined the stoichiometry of the subunits of the UAF complex, revealing there are two copies of histoneH3 and one copy of the remaining UAF subunits, including histone H4. Together, our results provide a new model suggesting that UAF contains a hybrid H3–H4 tetramer-like subcomplex.The results from this thesiswill help to reveal key mechanisms in Pol Itranscription activation.
    • Redesigning Adirondack Adventures: Analyzing Crowd Culture to Develop Social Media Marketing Strategies

      McFadden, Hannah (2016-12-01)
      The purpose of this thesis is to analyze present day crowd culture to better understand consumer behaviors and engagement to help redesign the brand and marketing strategy for Adirondack Adventures, a small white water rafting business in upstate New York. With small businesses struggling to take full advantage of social media platforms and the potential they offer, consumers and potential customers are left disengaged and consequently uninterested. By researching the correlation between Web 2.0 technology and the emergence of crowd culture it is my goal to develop a social media marketing strategy for Adirondack Adventures that will help establish their brand, increase their exposure, and grow their customer base to become a top competitor in their industry.
    • REELIN SIGNALING COORDINATES DENDRITICINITIATION AND CELLULAR POSITIONING BY NEURITESTABILIZATION

      Olson, Eric; O’Dell, Ryan (2015)
      The laminar organization characteristic of the adult mammalian neocortex is a product of the precise coordination of neuronal proliferation, migration, and differentiation. Among these processes, the biological signals controlling apical dendrite initiation and targeting are not completely understood.The secreted ligand Reelin is a largeextracellular matrix glycoprotein localized to the axonal plexus of themarginal zone, and mutations areassociated with severe disruptions in cellular organization in laminated brain regions. Although the Reelin signaling pathway has been traditionally describedas a modulator of neuronal migration, recent evidence suggests Reelin controlsneuronal orientation and subsequent dendritogenesis into the overlying marginal zoneduring a period of early cortical development known as preplate splitting.To explicitly characterize how Reelin coordinates the transition between migration and dendritogenesis and controls polarized apical dendrite initiation and growth, an ex uteroexplant model of early cortical developmentwas used for fixed tissue and multiphoton live imaging analysis. Our investigations revealed the apical dendrite of cortical neurons emerges via direct transformation of the leading process during terminal translocation.Both throughoutand after this migratory phase, the dendriticarbor demonstrated significant increases in growth and branching, typically initiatedafter leading process entryinto the Reelin-rich marginal zone.In the absence of Reelin signaling, mutant cortices demonstrated a significant proportion of neurons that successfully translocated, but showed unstable arbors and marginal zone avoidance after migration arrest. Application of exogenous Reelin protein rescued dendritekinetics and polarity within4 hours, resultinginthe retraction of tangentially orienteddendritessimultaneous with the extension of a highly branched,apicallyoriented primary process. These findings suggesta precise role of Reelin signaling in early cortical development in proper neuronal polarization and stabledendrite outgrowth into the marginal zone, an area otherwiseexclusionary for dendrites. Furthermore, it is suggested that appropriate dendritic arbor elaborationinto the marginal zone may not only promote terminal translocation, but also definesthe final position of migration arrest.Thisbody of work thus offers an important advancement in understanding Reelin’s role in polarized dendritic outgrowth and the subsequent knock-on effectsassociated withperturbationsof this signaling pathway.
    • Reelin Signaling in Oligodendrocyte Progenitor Cell Migration

      Osterhout, Donna; BHATTI, HARNEET (2016)
      Oligodendroglial progenitor cells (OPCs) are the precursors to the myelinating oligodendrocytes in the central nervous system (CNS). These cells are produced in the ventral neuroepithelium at later stages of cortical development, migrating into the cortex where they contact axons and differentiate, ultimately forming a myelin membrane. During the process of differentiation, OPCs undergo significant morphological changes, extending many processes which will make contact with axons. Once in contact with an axon, the oligodendrocyte process expands and begins to form the myelin membrane which will ensheathe the axon. Reelin is a highly conserved secretory glycoprotein, which has acritical role in directing neuronal migration. Reelin orchestrates the proper cortical layer formation and neuronal organization during brain development. In the absence of Reelin, the cerebral crotex is disorganized, with inverted cortical layers, generating devastating biological effects. Reelin acts through several cellular receptors, activating numerous downstream effectors and complex signaling cascades. If elements of the Reelin signalling pathway are disrupted,similar defects in migration can occur.Oligodendroglial cells, from the early progenitor cells to the mature myelinating cells secrete Reelin, but also express a receptor for Reelin and criticalelements of the intracellular Reelin signaling pathways. It is not known if these cells canrespond to Reelin. In this thesis, we examined the effects of Reelin on oligodendroglial cells, using both in vitroand in vivomethods. We demostrate a potentialrole for Reelin in modulating oligodendrocyte migration, but also identify a novel aspect ofReelin signalling in the biology of oligodendroglia.
    • REGULATION AND FUNCTION OF TUMOR SUPPRESSOR ECRG2 IN RELATION TO DNA DAMAGE AND MICROTUBULE DYNAMICS IN HUMAN MALIGNANCIES

      Huang, Ying; Patel, Harsh (2020)
      phageal Cancer-Related Gene 2 (ECRG2) is a novel tumor suppressor which is frequently mutated or downregulated in multiple human cancers. Previous studies have demonstrated that ECRG2 inhibits growth of cancer cells by inducing apoptotic death. However, the molecular basis of its regulation and involvement in DNA damage response remain to be elucidated. The function of tumor suppressor p53 in cellular response to stress conditions, such as DNA damage, has been well-established. In the present study, we report for the first time, that ECRG2 is a novel pro-apoptotic transcriptional target of p53 and ECRG2 expression is induced by DNA damage in a p53-dependent manner. Moreover, we demonstrate that disruption of ECRG2 leads to reduced apoptosis and improved survival following the treatment with DNA damage-inducing anticancer agent despite p53 activation in cancer cells. Significantly, we characterized a natural variant in ECRG2promoter (rs3214447) that is found in the genomes of ~38.5% of world population and showed that ECRG2 promoter with rs3214447 variant is defective in responding to p53 and DNA damage. Thus, ECRG2 is an important executor of p53-mediated apoptosis in response to DNA damage. We also report a novel biological function of ECRG2 and demonstrate that ECRG2 interacts with and stabilizes microtubules. ECRG2 was shown to protect the microtubules against the destabilization induced by cold and nocodazole treatment. In addition, we show that ECRG2 increases acetylation of microtubules, which is associated with more stable microtubules. Importantly, we demonstrate that ECRG2 disruption give rise to increased cell proliferation by elevated activation of Akt. Taken together, our findings ascribe a novel function to ECRG2 in the regulation of microtubule dynamics and cancer cell proliferation. ECRG2-mediated tumor suppressor activities elucidated in this dissertation are clinically significant. Our database analyses reveal that cancer patients with lower ECRG2expression in their tumors had poor prognosis and reduced disease-free survival as compared to their counterparts. These observations suggest that loss of ECRG2 expression and function confers survival advantage to cancer cells. Collectively, this dissertation highlights novel aspects of ECRG2 regulation and function in cancer cell sensitivity to DNA damage-inducing anticancer therapy, microtubule dynamics and cell proliferation.
    • REGULATION OF CELLULAR BIOENERGETICS IN CNS DEMYELINATING DISEASE

      Massa, Paul T.; Minchenberg, Scott (2017)
      Multiple Sclerosis (MS) is a debilitating neurological disease characterized by sclerotic inflammatory demyelination of the white matter tracts in the central nervous system (CNS). There is no “cure” for MS but rather disease modifying treatments that decrease relapse rates and slow disease progression. Due to the lack of insight into the pathogenesis of MS, animal models have been developed to study demyelination in the CNS. Two widely used models of demyelination are experimental autoimmune encephalomyelitis (EAE), and Theiler’s murine encephalomyelitis virus (TMEV). Our studies focused on TMEV mediated demyelination, which was dependent on the expression of the protein tyrosine phosphate SHP-1. SHP-1 is a major negative regulator of cytokine/growth factor signaling and a global deficiency triggers an acute macrophage mediated demyelination in C3H mice. SHP-1 deficient mice are also highly susceptible to systemic inflammation and dysmyelination. Our overall goal was to identify how SHP-1 is mediating susceptibility to inflammatory demyelination. We first demonstrated that SHP-1 deficient oligodendrocytes had increased reactive oxygen species (ROS) production resulting in downregulation of myelin gene expression and oxidation of myelin, a common finding in MS patients. To determine a source of the ROS we investigated how SHP-1 controls metabolic pathways as ROS production is tightly linked to metabolism. To determine how SHP-1 impacts bioenergetics, oligodendrocyte glycolytic and mitochondrial metabolism were quantified using the Seahorse XFe96 analyzer. We determined that SHP-1 enhances oligodendrocyte metabolism, which correlates with its ability to suppress STAT1 activity in oligodendrocytes. We corroborated these results via activation of STAT1 in oligodendrocytes with the proinflammatory cytokine IFN-γ recapitulating the metabolic defects in SHP-1 deficient oligodendrocytes. Based the role of SHP-1 in oligodendrocyte bioenergetics and the importance of macrophage-derived cytokine production during demyelination; we investigated a role for SHP-1 in macrophage bioenergetics. In macrophages, enhanced glycolysis drives activation and proinflammatory cytokine production. TMEV infection specifically induced glycolysis in GM-CSF-derived macrophages lacking SHP-1. This finding may explain why SHP-1 confers susceptibility to macrophage-mediated demyelination after TMEV infection. Overall we demonstrate a novel role for SHP-1 in controlling oligodendrocyte and macrophage bioenergetics that is highly relevant in expanding our understanding of CNS demyelinating disease.
    • RELN AS A CANDIDATE GENE FOR AUTISM SPECTRUM DISORDER (ASD)

      Howell, Brian; Lammert, Dawn (2017)
      Autism spectrum disorder (ASD) affects approximately 1 in 45 people, and is characterized by deficits in social communication and repetitive behaviors. Sequencing advancements have enabled the identification of numerous candidate genes, but precisely how these genes contribute to ASD remains largely unknown. RELNis consistently implicated as a candidate gene for autism. The encoded secreted glycoprotein, Reelin is important for proper brain developmental and postnatal synapse function. Here we examine the molecular and cellular consequences of the de novo RELNmutation R2290C. This mutation falls in a conserved arginine-amino acid-arginine (RXR) motif that is found within the Reelin subrepeat structure. Several other ASD patient mutations fall with in this consensus and all examined reduce Reelin secretion. Based on this we tested two hypothesis: (1) that the mutations reduce Reelin signaling and (2) that they have a gain-of-function consequence, such as ER stress. Using an engineered cell line with a heterozygous RELNR2290C mutation and the RELN Orleans (Orl) mouse line that produces nearly full length Reelin that is defective for secretion, we found evidence for both increased Dab1 and increased PDIA1 expression. Since, like most genes implicated in ASD RELNlikely acts in a multifactorial manner, we investigated whether second site mutations might contribute to ASD-related behaviors. Towards this end we crossed the heterozygous Orl and Shank3b mice to model two hits that are present in at least one ASD proband. We found that the resulting double heterozygousmice had impaired socialization and altered ultrasonic vocalizations. Furthermore, forebrain and cerebellar lysates showed increased PSD-95, identifying a potentially common mechanism and therapeutic target for ASD. These studies are the first to investigate the biological relevance of RELNcoding mutations in ASD.
    • Report from the second international meeting of the attention deficit hyperactivity disorder Molecular Genetics Network

      Faraone, Stephen V. (Wiley, 2001)
      Given evidence from twin, family, and adoption studies of genetic influence on attention deficit hyperactivity disorder (ADHD), a growing number of researchers have initiated molecular genetics studies to explore the influence of specific genes on this condition. In 1999, these investigators convened to discuss ways of sharing information and facilitating collaborations across research sites. Enthusiastic response to this first conference prompted an even larger group of investigators to come together this year. This recent meeting, held in London, began with a presentation of Hypescheme, an operational criteria checklist developed in an effort to promote the reliable communication of diagnostic and other relevant clinical information related to ADHD. The benefits and limitations of Hypescheme, as well as the continued challenges to collaboration, were discussed. A new ADHD-specific rating scale, developed to be of use in genetic analyses, was also presented. Focus then turned to collaborative projects proposed by investigators and practical suggestions regarding joint data analyses projects. Finally, new data from individual sites were presented. Because the mode of inheritance of ADHD is likely to be complex, efforts to collaborate and cross-validate findings remain an important priority for researchers studying the molecular genetics of this disorder. © 2001 Wiley-Liss, Inc.
    • Representational State Transfer as a Web Service

      Desai, Dhruv; Sengupta, Sam; Adviser; Novillo, Jorge; Reviewer; Andriamanalimanana, Bruno; Reviewer (2015-12-01)
      This report is a study on Representational State Transfer architectural style and its usefulness for implementing web service. This report will highlight the differences in perceiving REST as an architectural style and as a web service. This document will also discuss web services in general and highlight important differences between the different web services in programming languages. The goal of this report is to clarify the term REST as an architectural style which has proved to be a popular choice for implementing a web service rather than REST being termed as a web service and compare Web Services based on its performance in a Java Application.
    • Research Paper And Video Project About Music Technology Evolution And Its Effects On Artist Revenue and Consumer Listening

      Stam, Kathryn; Thesis Advisor; Lizardi, Ryan; Second Reader; Lazar, Neer (2021-06)
      In this paper I will try to show how the technology that changed over time affected both artists and music consumers. The theory from some of the literature I found is that disruptions in music technology also had many economic impacts to both artists and their audience. In the literature it is suggested that streaming rectified the revenue hit that was derived from the ill effects of digital piracy. In this paper and in the accompanying video that can be found here - https://drive.google.com/file/d/15IIBwwFLZqpnfqPl_pqmR YsAHgfjMuiN/view?usp=sharing I will describe the evolution of the technological changes and show that these advances also had the same exponential curve in change very similar to the changes that occurred in print although the ability to record sound arrived thousands of years after the ability to record letters and words. However, at some point the technological changes created the same kind of disruptions - meaning the ability to record sound and transport it and listen to it in various ways. This created markets and economic advancements that were not there before - again similar in many ways to technological changes in other fields. Later in this paper I will focus on the last few years of these changes with an emphasis on streaming technologies. This in my opinion a change that is still ongoing and was transformational in the way revenue distribution came back after a very tough time that included a breakdown in the established industry and the piracy that affected it during this crisis. Another theory is that the instant gratification of on demand technology that gives consumers exactly what they want when they want it was also solved with streaming music services. The literature that I chose to cite and that I based my research on was primarily from trade magazines and industry news. These articles paint a picture of a changing landscape in the music industry and also talk about some of my ideas that led me to research and write this paper.
    • Revisiting the factor structure for positive and negative symptoms: evidence from a large heterogeneous group of psychiatric patients

      Toomey, R; Kremen, W S; simpson, J C; Samson, J A; Seidman, L J; Lynons, M J; Faraone, Stephen V.; Tsuang, M T (American Psychiatric Association Publishing, 1997-03)
      O bjective: The factor structures of individual positive and negative symptoms as well as global ratings were examined in a diagnostically heterogeneous group of subjects. Method: Subjects were identified through a clinical and family study of patients with major psychoses at a VA medical center and evaluated with the Scale for the Assessment of N egative Symptoms and the Scale for the Assessment of Positive Symptoms. For the examination of global-level factor structures (N =630), both principal-component analysis and factor analysis with orthogonal rotation were used. Factor analysis was used for the examination of item-level factor structures as well (N =549). Results: The principal-component analysis of global ratings revealed three factors: negative symptoms, positive symptoms, and disorganization. The factor analysis of global ratings revealed a negative symptom factor and a positive symptom factor. The itemlevel factor analysis revealed two negative symptom factors (diminished expression and disordered relating), two positive symptom factors (bizarre delusions and auditory hallucinations), and a disorganization factor. Conclusions: The generation of additional meaningful factors at the item level suggests that important information about symptoms is lost when only global ratings are viewed. Future work should explore clinical and pathological correlates of the more differentiated item-level symptom dimensions
    • Risk variants and polygenic architecture of disruptive behavior disorders in the context of attention-deficit/hyperactivity disorder

      Demontis, Ditte; Walters, Raymond K.; Rajagopal, Veera M.; Waldman, Irwin D.; Grove, Jakob; Als, Thomas D.; Dalsgaard, Søren; Ribasés, Marta; Bybjerg-Grauholm, Jonas; Bækvad-Hansen, Maria; et al. (Springer Science and Business Media LLC, 2021-01-25)
      Attention-Deficit/Hyperactivity Disorder (ADHD) is a childhood psychiatric disorder often comorbid with disruptive behavior disorders (DBDs). Here, we report a GWAS meta-analysis of ADHD comorbid with DBDs (ADHD + DBDs) including 3802 cases and 31,305 controls. We identify three genome-wide significant loci on chromosomes 1, 7, and 11. A meta-analysis including a Chinese cohort supports that the locus on chromosome 11 is a strong risk locus for ADHD + DBDs across European and Chinese ancestries (rs7118422, P = 3.15×10−10, OR= 1.17). We find a higher SNP heritability for ADHD + DBDs (h2 SNP = 0.34) when compared to ADHD without DBDs (h2 SNP = 0.20), high genetic correlations between ADHD + DBDs and aggressive (rg = 0.81) and anti-social behaviors (rg = 0.82), and an increased burden (polygenic score) of variants associated with ADHD and aggression in ADHD + DBDs compared to ADHD without DBDs. Our results suggest an increased load of common risk variants in ADHD + DBDs compared to ADHD without DBDs, which in part can be explained by variants associated with aggressive behavior.
    • Risk variants and polygenic architecture of disruptive behavior disorders in the context of attention-deficit/hyperactivity disorder

      Demontis, Ditte; Walters, Raymond K.; Rajagopal, Veera M.; Waldman, Irwin D.; Grove, Jakob; Als, Thomas D.; Dalsgaard, Søren; Ribasés, Marta; Bybjerg-Grauholm, Jonas; Bækvad-Hansen, Maria; et al. (Springer Science and Business Media LLC, 2021-01-25)
      Attention-Deficit/Hyperactivity Disorder (ADHD) is a childhood psychiatric disorder often comorbid with disruptive behavior disorders (DBDs). Here, we report a GWAS meta-analysis of ADHD comorbid with DBDs (ADHD + DBDs) including 3802 cases and 31,305 controls. We identify three genome-wide significant loci on chromosomes 1, 7, and 11. A meta-analysis including a Chinese cohort supports that the locus on chromosome 11 is a strong risk locus for ADHD + DBDs across European and Chinese ancestries (rs7118422, P = 3.15×10-10, OR = 1.17). We find a higher SNP heritability for ADHD + DBDs (h2SNP = 0.34) when compared to ADHD without DBDs (h2SNP = 0.20), high genetic correlations between ADHD + DBDs and aggressive (rg = 0.81) and anti-social behaviors (rg = 0.82), and an increased burden (polygenic score) of variants associated with ADHD and aggression in ADHD + DBDs compared to ADHD without DBDs. Our results suggest an increased load of common risk variants in ADHD + DBDs compared to ADHD without DBDs, which in part can be explained by variants associated with aggressive behavior.
    • ROLE OF BMP AND ACTIVIN/NODALSIGNALING REPRESSION IN RETINALPROGENITOR CELL SPECIFICATION ANDCONE PHOTORECEPTOR GENESIS

      Viczian, Andrea; Wong, Kimberly (2017)
      Eye formation begins with the specification of the eye field from the anteriorneural plate during the transition from gastrulation to neuralization. The morphogeneticgradients formed by BMP and Activin/Nodal ligands organize the body axis andregulate intracellular signals to bias the cell lineages.Therefore, to understand theextracellular signaling mechanisms governing eye field specification, we looked closerat the mechanisms responsible for neuralization. This project takes advantage of thedevelopmental accessibility of theXenopus laevisembryo to investigate the role ofBMP and Activin/Nodal signaling pathways during early eye development.Nogginis a secreted BMP antagonist and is sufficient to induce formation of ectopic retinaltissue. My results presented in Chapter 2 show that intracellular repression of BMP-Smad1/5/8 and Activin/Nodal-Smad2/3 signaling was sufficient to replicate the retina-promoting activity of Noggin and efficiently drive pluripotentXenopusprimitive ectodermto a retinal progenitor cell fate. Furthermore, my work presented in Chapter 3 suggeststhat repression of BMP and Activin/Nodal in the anterior neural plate allows the anteriorneural patterning transcription factor, Otx2, to directly activate expression of the earliesteye field transcription factor,tbx3. This study elucidates the initial step by which theanterior neural plate is patterned to specify the eye field. We next translated our findings to mouse embryonic stem cell culture (Chapter 4). We observed that mouse embryonic stemcells can be efficiently directed towards retinal progenitor cells by first converting themto an early primitive ectoderm-like state, followed by simultaneous repression of BMPand Activin/Nodal and activation of FGF signaling. After differentiation, we observedthat photoreceptor genesis is synchronized, resulting in 96% of aggregates expressingmarkers for cone photoreceptors after 9 days. This differentiation protocol is more efficientand quicker than previously published mouse stem cell protocols. Optimizing treatmentconditions resulted in up to 62% of cells expressing the cone/rod photoreceptor marker,CRX. This study was the first to show that photoreceptor-like cells can be generated frommouse pluripotent stem cells as efficiently as published human pluripotent stem cell reports,but with a shorter culture period. These studies will provide the basis of future work todetermine the underlying molecular mechanism driving retinal differentiation.
    • Role of RPTPzeta/phosphacan in the neural extracellular matrix

      Matthews, Rick; Eill, Geoffrey (2020)
      The mammalian brain is the most structurally and functionally complex system in biology. In order to carry out diverse functions such as thought and cognition, neurons in the brain must properly differentiate, make millions of functional interconnections, and incredibly be able to maintain those interconnections while retaining plasticity and the ability to learn throughout its lifetime. In order for neurons to carry out these complex functions, they must have an intricate relationshipwith their extracellular environment, which provides numerous molecules, such as growth factors and neurotransmitters, and physical cues to initiate critical downstream signaling cascades. In the central nervous system (CNS), the neural extracellular matrix (ECM) largely organizes this extracellular environment, and as such, is implicated in a multitude of neuronal functions. Not only can it serve as a physical barrier, the neural ECM is shown to regulate neuronal cell differentiation, migration, synaptogenesis, and maintain the mature state by restricting plasticity and neurite outgrowth. Of particular import, a subset of the neural ECM, the perineuronal net (PNN), is implicated to regulate neuronal plasticity in the CNS. PNNs were historically believed to be critical for restricting experience dependent plasticity in the brain but more recently shown to regulate several forms of learning and memory, in addition to multiple neurological diseases. However, despite these implicated functions, PNNs comprise only a fraction of the total ECM in the CNS. A majority of the neural ECM is derived from the diffuse ECM, a structure that is ubiquitously expressed throughout the CNS. As the diffuse ECM is very similar in molecular composition and structure to PNNs, it is difficult to specifically target PNNs for functional and mechanistic studies.As such, a better toolset is needed to differentiate the contributions ivbetween PNNs and the diffuse ECM in regulating plasticity and learning and memory. To develop thistoolset, there is a great need to better understand PNN molecular composition and structure. Therefore, the purpose of this work was to provide critical insight into the molecular composition and structure of PNNs soas to better understand its function in the CNS. In Chapter 2, using multiple ECM genetic knockout models, we show compelling evidence of an additional PNN anchor that importantlylays the groundworkforfuture functional studies. Specifically, we suggestchondroitin sulfate proteoglycan (CSPG) phosphacan, secreted isoform of receptor protein tyrosine phosphatase zeta (RPTPζ), iscritical for PNN structure as it partially anchors PNNs to the neuronal surface through cooperation with tenascin-R. Additionally, as the neural ECM is involved in numerous neurological diseases, in Chapter 3, we investigated the function of major ECM component, RPTPζ, in a group of O-mannosyl related congenital muscular dystrophy with associated brain abnormalities (CMD). Our data suggest a possible role of RPTPζ in proper cortical lamination in a CMD mouse model. Interestingly, we found evidence of a novel O-mannosyl substrate in the developing brain that could critically contribute to the underlying deficits of CMD. In conclusion, the neural ECM, once previously disregarded in the field, is becoming a novel source to understand mature mammalian brain function and disease, but more work is needed to better differentiate the specific roles of its substructures.