• CAG-Repeat length in exon 1 of KCNN3 does not influence risk for schizophrenia or bipolar disorder: A meta-analysis of association studies

      Glatt, Stephen J.; Faraone, Stephen V.; Tsuang, Ming T. (Wiley, 2003-07-30)
      Schizophrenia and bipolar disorder both showsomeevidence for genetic anticipation. In addition, significant expansion of anonymous CAG repeats throughout the genome has been detected in both of these disorders. The gene KCNN3, which codes for a small/ intermediate conductance, calcium-regulated potassium channel, contains a highly polymorphic CAG-repeat array in exon 1. Initial evidence for association of both schizophrenia and bipolar disorder with increased CAG-repeat length of KCNN3 has not been consistently replicated. In the present study, we performed several metaanalyses to evaluate the pooled evidence for association with CAG-repeat length of KCNN3 derived from case-control and family-based studies of both disorders. Each group of studies was analyzed under two models, including a test for direct association with repeat length, and a test for association with dichotomized repeat-length groups. No evidence for a linear relationship between disease risk and repeat length was observed, as all pooled odds ratios approximated 1.0. Results of dichotomized allelegroup analyses were more variable, especially for schizophrenia, where case-control studies found a significant association with longer repeats but family-based studies implicated shorter alleles. The results of these meta-analyses demonstrate that the risks for both schizophrenia and bipolar disorder are largely, if not entirely, independent of CAG-repeat length in exon 1 of KCNN3. This study cannot exclude the possibility that some aspect of this polymorphism, such as repeat-length disparity in heterozygotes, influences risk for these disorders. Further, it remains unknown if this polymorphism, or one in linkage disequilibrium with it, contributes to some distinct feature of the disorder, such as symptom severity or anticipation.
    • Can sodium/hydrogen exchange inhibitors be repositioned for treating attention deficit hyperactivity disorder? An in silico approach

      Faraone, Stephen V.; Zhang-James, Yanli (Wiley, 2013-10-17)
      Medications for attention deficit hyperactivity disorder (ADHD) are only partially effective. Ideally, new treatment targets would derive from a known pathophysiology. Such data are not available for ADHD. We combine evidence for new etiologic pathways with bioinformatics data to assess the possibility that existing drugs might be repositioning for treating ADHD. We use this approach to determine if prior data implicating the sodium/hydrogen exchanger 9 gene (SLC9A9) in ADHD implicate sodium/hydrogen exchange (NHE) inhibitors as potential treatments. We assessed the potential for repositioning by assessing the similarity of drug–protein binding profiles between NHE inhibitors and drugs known to treat ADHD using the Drug Repositioning and Adverse Reaction via Chemical–Protein Interactome server. NHE9 shows a high degree of amino acid similarity between NHE inhibitor sensitive NHEs in the region of the NHE inhibitor recognition site defined for NHE1. We found high correlations in drug–protein binding profiles among most ADHD drugs. The drug–protein binding profiles of some NHE inhibitors were highly correlated with ADHD drugs whereas the profiles for a control set of nonsteroidal anti-inflammatory drugs (NSAIDs) were not. Further experimental work should evaluate if NHE inhibitors are suitable for treating ADHD. © 2013 Wiley Periodicals, Inc.
    • CD11C+ T-BET+ B CELLS IN INFECTION AND AUTOIMMUNITY

      Winslow, Gary; Levack, Russell (2020)
      CD11c+ T-bet+ B cells serve crucial roles in both protective immunity and autoimmunity.However, the ontogeny of these cells remains unclear, and strategies to target them in vivo have yet to be identified. Here, we demonstrate that developing CD11c+ T-bet+ B cells received help in the form of IL-21, IFN-γ, and CD40L from a population ofT follicular helper 1(TFH1)cells outside of formal germinal centers (GC). These TFH1cells provided help to developing CD11c+ T-bet+ B cells in two distinct phases: IFN-gwas provided early following infection, and CD40L was provided later. Unlike the TFH1cells, CD11c+ T-bet+ B cells required the GC-associated transcription factor Bcl-6 for their development, but not T-bet. While the CD11c+ B cells that arose in the absence of T-bet appeared nearly identical to their T-bet-competent counterparts,they did not switch to IgG2c. These data support a model where, in the absence of formal GCs, TFH1cells provide GC-like help to developing CD11c+ T-bet+ B cells and while T-bet is not required for the development of these T-bet+ B cells,it is required for appropriate class-switch recombination (CSR). Our work also demonstrates that mature CD11c+ T-bet+ B cells, which arise in both immunity and autoimmunity,wereeliminated following treatment with the adenosine 2a receptor (A2aR) agonist CGS-21680. Depletion of these CD11c+ T-bet+ B cells occurred in a B cell-intrinsic manner and was corelated with improved disease outcome in a mouse model of lupus. Preliminary data indicated that human CD11c+ B cells expressed the A2aR,and these cells were depleted following CGS-21680 treatment in vitro, suggesting that A2aR-agonistadministrationmay also be effective in the treatment of human autoimmune diseaseswhere CD11c+ Bcell play a role. Overall, this work provides novel insight into the development of T-bet+ B cells and identifies the first pharmacological approach to target these cells in vivo.
    • Characteristics of Adults with Attention Deficit Hyperactivity Disorder Plus Substance Use Disorder: The Role of Psychiatric Comorbidity

      Wilens, Timothy E.; Kwon, Anne; Tanguay, Sarah; Chase, Rhea; Moore, Hadley; Faraone, Stephen V.; Biederman, Joseph (Wiley, 2005-01)
      The objective of the study was to investigate the characteristics of adults with Attention Deficit Hyperactivity Disorder (ADHD) or substance use disorder (SUD), especially in the context of comorbid psychiatric disorders. Subjects were adults (n ¼ 78) participating in a controlled family study of ADHD and SUD. Four groups were identified based on a diagnosis of ADHD or SUD: ADHD, SUD, ADHDþSUD, and neither ADHD nor SUD. All diagnoses were determined by structured clinical interview for DSM IV. Rates of psychiatric comorbidity were lowest in the controls, intermediate in the ADHD and SUD groups, and highest in the ADHDþSUD group. Relative to controls, the ADHD, SUD, and ADHDþSUD groups had higher rates of major depression (z ¼ 1.98, p ¼ 0.05), conduct disorder (z ¼ 2.0, p ¼ 0.04), antisocial personality disorder (z ¼ 2.6, p ¼ 0.009), agoraphobia (z ¼ 2.5, p ¼ 0.01) and social phobia (z ¼ 2.7, p ¼ 0.007). Higher rates of psychiatric comorbidity, especially mood and anxiety disorders, exist in subjects with SUDþADHD relative to subjects with SUD, ADHD, or controls. Clinicians need to be attentive to other psychiatric disorders that may occur in the large group of adults with ADHDþSUD.
    • Characterization of Hic-5 in Cancer Associated Fibroblasts: A Role in Extracellular Matrix Deposition and Remodeling

      Turner, Christopher; Goreczny, Gregory (2017)
      Hic-5 (TGFβ1i1) is a focal adhesion scaffold protein that has previously been implicated in many cancer-related processes. However, the contribution of Hic-5 during tumor progression has never been evaluated, in vivo. In Chapter 2 of this thesis, I crossed our Hic-5 knockout mouse with the MMTV-PyMT breast tumor mouse model to assess the role of Hic-5 in breast tumorigenesis. Tumors from the Hic-5 -/-;PyMT mouse exhibited an increased latency and reduced tumor growth. Immunohistochemical analysis of the Hic-5 -/-;PyMT tumors revealed that the tumor cells were less proliferative. However isolated tumor cells exhibit no difference in growth rate. Surprisingly, Hic-5 expression was restricted to the tumor stroma. Further analysis showed that Hic-5 regulates Cancer Associated Fibroblast (CAF) contractility and differentiation which resulted in a reduced ability to deposit and reorganize the extracellular matrix (ECM) in two-and three-dimensions. Furthermore, Hic-5 dependent ECM remodeling supported the ability of tumor cells to metastasize and colonize the lungs.The molecular mechanisms by which CAFs mediate ECM remodeling remains incompletely understood. In Chapter 3 of this thesis, I show that Hic-5 is required to generate fibrillar adhesions, which are specialized structures that are critical for the assembly of fibronectin fibers. Hic-5 was found to promote fibrillar adhesion formation through a newly characterized interaction with tensin1, a scaffold protein that binds to β1 integrin and actin. Furthermore, this interaction was mediated by Src-dependent phosphorylation of Hic-5 in two and three-dimensional matrix environments to prevent β1 integrin internalization and subsequent degradation in the lysosome. This work highlights the importance of the focal adhesion protein, Hic-5 during breast tumorigenesis and provides insight into the molecular machinery driving CAF-mediated ECM remodeling.
    • Characterizing the Role of the Epsilon Subunit in Regulation of the Escherichia coli ATP Synthase.

      Duncan, Thomas; Shah, Naman (2015)
      The F-type ATP synthase is a rotary nanomotor central to cellular energy metabolism in almost all living organisms. In bacteria, the enzyme also plays a role in nutrient uptake and pH regulation underlining its importance. All ATP synthases can be inhibited by ADP, whereas in bacteria, the enzyme is alsoautoinhibitedbyits ε subunit. The inhibition involves a drastic conformationa l change of the C-terminal domain of the ε subunit (εCTD)thatblockscatalytic turnover. Thisregulation by ε is believed to play an important role in maintaining viability of the cell. Recent development in the field of antibiotics has validated ATP synthase as a drug target against pathogenic bacteria. Thus, there is a renewed interest in studying the role of the ε subunit in regulation of the enzyme and exploiting it to develop antimicrobials that can kill pathogenic bacteria. The present work describes advances in our understanding of the regulatory interactions of εCTD in E. coli ATP synthase.In the first approach, we used an optical binding assay to understand the transitions of εCTD between its active and inhibitory conformations.Using different ligands we revealedthe relationship between ADP inhibition and ε inhibition. In the second novel approach, the terminal five amino acids of εCTD were deleted to observe the effects on in vivo and in vitro functions of ATP synthase. The results obtained from these studies advance our understanding of εinhibition inbacteria and also provide a noveltarget within bacterial ATP synthase to obtain antibacterial drugs.
    • The Chemosensory-­Related Consequences of Fetal Ethanol or Fetal Nicotine Exposure: Their Contribution to Postnatal Nicotine Acceptance

      Youngentob, Steven; MANTELLA, NICOLE (2015)
      Human studies demonstrate a predictive association between gestational exposure to alcohol or nicotine and the probabilityoflater nicotine dependence.The flavor qualitiesof both drugsare known to influencetheir earlyacceptance and they share the perceptual attributesof an aversive odor, bitter taste and oral irritation.This dissertationexamined whether there are chemosensory-­‐related consequences offetal: (1) alcohol exposurethat contribute toenhanced nicotine acceptance; or (2)nicotine exposure that also enhances acceptance. The study rationale was drivenby overlappingliteraturesrelated to: (1) the relationship between gestational exposurewith chemosensory stimuli and their postnatal acceptance; (2) lessons learned from prenatal alcohol exposure and its postnatal consequences; and (3) perceptual commonalities between the flavor of alcohol and nicotine.Alcohol studies: rats were alcohol-­‐exposed during gestationvia the dams’ liquid diet. Control damsreceived ad libaccessto an iso-­‐caloric, iso-­‐nutritive diet. Nicotine studies: dams’ were implanted with a mini-­‐osmotic pump containing nicotine.Control animals received either vehicle only or no pump. Behaviorally, we found that fetal alcohol exposed adolescent rats showed anenhanced nicotine odor
    • Comorbidity of ADHD and adult bipolar disorder: A systematic review and meta-analysis

      Schiweck, Carmen; Arteaga-Henriquez, Gara; Aichholzer, Mareike; Edwin Thanarajah, Sharmili; Vargas-Cáceres, Sebastian; Matura, Silke; Grimm, Oliver; Haavik, Jan; Kittel-Schneider, Sarah; Ramos-Quiroga, Josep Antoni; et al. (Elsevier BV, 2021-05)
      Attention-deficit / hyperactivity disorder (ADHD) and Bipolar Disorder (BD) are common mental disorders with a high degree of comorbidity. However, no systematic review with meta-analysis has aimed to quantify the degree of comorbidity between both disorders. To this end we performed a systematic search of the literature in October 2020. In a meta-analysis of 71 studies with 646,766 participants from 18 countries, it was found that about one in thirteen adults with ADHD was also diagnosed with BD (7.95 %; 95 % CI: 5.31-11.06), and nearly one in six adults with BD had ADHD (17.11 %; 95 % CI: 13.05-21.59 %). Substantial heterogeneity of comorbidity rates was present, highlighting the importance of contextual factors: Heterogeneity could partially be explained by diagnostic system, sample size and geographical location. Age of BD onset occurred earlier in patients with comorbid ADHD (3.96 years; 95 % CI: 2.65-5.26, p < 0.001). Cultural and methodological differences deserve attention for evaluating diagnostic criteria and clinicians should be aware of the high comorbidity rates to prevent misdiagnosis and provide optimal care for both disorders.
    • The concept of target features in schizophrenia research

      Tsuang, M. T.; Faraone, Stephen V. (Wiley, 1999-05)
      Target features are clinical or neurobiological characteristics that arc expressions of the underlying predisposition to an illness. They comprise a wide range of phenomena, from thc classic signs and symptoms of psychopathology to sophisticated measures of brain structure and function. For schizophrenia, many target features have been identified. These include eye tracking dysfunction, attentional impairment, allusive thinking, neurological signs, thought disorder, characteristic auditory evoked potentials, neuropsychological impairment, structural brain abnormalities and functional brain abnormalities. In their most pathological forms, thcse features are present among many schizophrenic patients, yet it is their presence among their non-psychotic relatives that shows them to be target features. We discuss the theoretical background for target features, present examples and describe how the discovery of target features has implications I for schizophrenia research.
    • Connexin43 and immunity : macrophage phagocytosis, cardiac calcinosis and autoimmune myocarditis

      Steven Taffet; Aaron Glass (2013)
      Connexin43 (Cx43) is a gap junction protein best known for coupling the cytoplasms of cardiac myocytes and allowing the efficient conduction of action potentials throughout the heart. In addition to the heart, Cx43 is also highly expressed in many immune cells and it has been attributed numerous roles in immunity. One such reported role was in macrophage phagocytosis. The first chapter in this dissertation explored the phagocytic activity of cultured and primary murine macrophages from wild type (WT) and Cx43-deleted (Cx43-/-) macrophages. No difference in phagocytic uptake was observed between the two groups using a series of target particles, indicating that Cx43 is dispensable for phagocytosis in macrophages. Given the spectrum of immune functions in which Cx43 has been ascribed a role, we set out to characterize its effect on a model of autoimmune myocarditis (EAM). Using the area of cardiac inflammatory infiltrate as a correlate of disease severity, we observed the progression of the disease to be independent of Cx43 status utilizing WT and Cx43-heterozygous (Cx43+/-) animals as well as radiation chimeric mice reconstituted with cells from donor WT, Cx43+/- and Cx43-/- mice. Although the severity of EAM did not measurably change when induced in animals with differing levels of Cx43 expression, substantial changes to ventricular Cx43 were noted in diseased hearts. Large foci were observed that completely lacked Cx43 immunofluorescence signal. Areas surrounding these foci exhibited disrupted Cx43 patterns such as internalization and lateralization. Similar alterations to Cx43 were also observed in the BALB/cByJ strain of laboratory mice that develop a spontaneous myocarditic disease. To investigate the electrophysiological ramifications of EAM, especially in the context of Cx43+/- mice, ECGs were recorded from animals over the course of EAM. Significant changes to the QRS interval were noted, including prolongation that was only observed in Cx43+/- animals.
    • Consortium neuroscience of attention deficit/hyperactivity disorder and autism spectrum disorder: The ENIGMA adventure

      Hoogman, Martine; Rooij, Daan; Klein, Marieke; Boedhoe, Premika; Ilioska, Iva; Li, Ting; Patel, Yash; Postema, Merel C.; Zhang‐James, Yanli; Anagnostou, Evdokia; et al. (Wiley, 2020-05-18)
      Neuroimaging has been extensively used to study brain structure and function in individuals with attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) over the past decades. Two of the main shortcomings of the neuroimaging literature of these disorders are the small sample sizes employed and the heterogeneity of methods used. In 2013 and 2014, the ENIGMA-ADHD and ENIGMA-ASD working groups were respectively, founded with a common goal to address these limitations. Here, we provide a narrative review of the thus far completed and still ongoing projects of these working groups. Due to an implicitly hierarchical psychiatric diagnostic classification system, the fields of ADHD and ASD have developed largely in isolation, despite the considerable overlap in the occurrence of the disorders. The collaboration between the ENIGMA-ADHD and -ASD working groups seeks to bring the neuroimaging efforts of the two disorders closer together. The outcomes of case–control studies of subcortical and cortical structures showed that subcortical volumes are similarly affected in ASD and ADHD, albeit with small effect sizes. Cortical analyses identified unique differences in each disorder, but also considerable overlap between the two, specifically in cortical thickness. Ongoing work is examining alternative research questions, such as brain laterality, prediction of case–control status, and anatomical heterogeneity. In brief, great strides have been made toward fulfilling the aims of the ENIGMA collaborations, while new ideas and follow-up analyses continue that include more imaging modalities (diffusion MRI and resting-state functional MRI), collaborations with other large databases, and samples with dual diagnoses.
    • A Controlled Study of Behavioral Inhibition in Children of Parents With Panic Disorder and Depression

      Rosenbaum, Jerrold F.; Biederman, Joseph; Hirshfeld-Becker, Dina R.; Kagan, Jerome; Snidman, Nancy; Friedman, Deborah; Nineberg, Allan; Gallery, Daniel J.; Faraone, Stephen V. (American Psychiatric Association Publishing, 2000-12)
      Objective: “Behavioral inhibition to the unfamiliar” has been proposed as a precursor to anxiety disorders. Children with behavioral inhibition are cautious, quiet, introverted, and shy in unfamiliar situations. Several lines of evidence suggest that behavioral inhibition is an index of anxiety proneness. The authors sought to replicate prior findings and examine the specificity of the association between behavioral inhibition and anxiety. Method: Laboratory-based behavioral observations were used to assess behavioral inhibition in 129 young children of parents with panic disorder and major depression, 22 children of parents with panic disorder without major depression, 49 children of parents with major depression without panic disorder, and 84 children of parents without anxiety disorders or major depression (comparison group). A standard definition of behavioral inhibition based on previous research (“dichotomous behavioral inhibition”) was compared with two other definitions. Results: Dichotomous behavioral inhibition was most frequent among the children of parents with panic disorder plus major depression (29% versus 12% in comparison subjects). For all definitions, the univariate effects of parental major depression were significant (conferring a twofold risk for behavioral inhibition), and for most definitions the effects of parental panic disorder conferred a twofold risk as well. Conclusions: These results suggest that the comorbidity of panic disorder and major depression accounts for much of the observed familial link between parental panic disorder and childhood behavioral inhibition. Further work is needed to elucidate the role of parental major depression in conferring risk for behavioral inhibition in children.
    • Deciphering a hippocampus to hypothalamus feeding circuit via the septal nucleus.

      Yang, Yunlei; Sweeney, Patrick (2017)
      The neural circuits controlling feeding are concentrated in the hypothalamus and hindbrain. These circuits primarily control homeostatic feeding behavior, which can be broadly defined as increasing feeding in response to hunger or decreasing feeding in response to satiety. However, non-homeostatic factors, such as the emotional state of an animal, can also profoundly affect feeding behavior. Therefore, the current thesis project sought to determine how primary emotion centers in the brain influence the known homeostatic feeding circuitry in the hypothalamus. In particular, given that ventral hippocampus (vHPC) and septum are involved in emotional processes, influence feeding behavior, and are anatomically connected to hypothalamic feeding circuitry, this dissertation aimed to determine the cell-types in vHPC and septum that control feeding and to functionally connect these cell-types to the primary feeding circuitry located in the hypothalamus. To accomplish these central aims, chemogenetic and optogenetic approaches were utilized to selectively manipulate neural activity within distinct ventral hippocampal and septal cell types and neural circuits. These approaches were complemented by traditional anterograde and retrograde tracing techniques and chemo/optogenetic circuit mapping approaches to define the neural circuits responsible for vHPC and septal control of feeding behavior. We find that chemogenetic activation of ventral hippocampal glutamate neurons reduces feeding, while inhibition facilitates feeding. We further dissect a functional neural circuit pathway from ventral hippocampus to lateral septum that is sufficient to suppress feeding behavior. Within the septum, both chemo/optogenetic activation of septal GABAergic neurons reduces feeding, while inhibition of these neurons increases food intake. Utilizing optogenetic circuit manipulation approaches, we demonstrate that septal GABAergic neurons reduce feeding, at least in part, by projecting to hyperphagia-inducing GABAergic neurons located within the lateral hypothalamus. Taken together, our findings expand upon the known roles for ventral hippocampus and septum in energy homeostasis by providing the specific cell-types and neural circuits governing vHPC and septal control of feeding behavior. Given the role for ventral hippocampus and septum in emotional processes and energy homeostasis, we propose that the described vHPC and septal circuits represent promising neural circuits for investigating interactions between feeding, emotional state, and motivated behavior.
    • DECIPHERINGGLUTAMATERGIC NEUROTRANSMITTER SPECIFICATION IN THE ZEBRAFISH SPINAL CORD

      Lewis, Kate; Hilinski, William (2016)
      The correct specification of neurotransmitter phenotypes is crucial for properly functioning neuronal circuitry. Neurons specify their neurotransmitter phenotypes via transcription factors that they express as they differentiate. Often, transcription factors that specify neurotransmitter phenotypes are expressed in multiple populations with the same neurotransmitter phenotype. Since, the transcription factors that specify this characteristic are not yet known for all spinal cord glutamatergic populations, we identified additional transcription factors expressed at relatively higher levels in glutamatergic neurons compared to inhibitory neurons. We have functionally tested three of these (Lmx1bb, Skor1a and Skor1b) to determine if they are required for correct spinal, glutamatergic phenotypes. We demonstrate that Lmx1b likely maintains a subset of glutamatergicphenotypes in the spinal cord. In lmx1bb mutant embryos, the number of cells that initially express glutamatergic markers are unchanged but become reduced at 36 h and to a greater degree at 48 h. In contrast, we observe no changes in the total number of dI5 or V0v neurons, which express lmx1bb,nor do we detect elevated levels of apoptosis between 36 h and 48 h in lmx1bb mutants. Lastly, we show that at least some of the cells that lose their glutamatergic neurotransmitter phenotype are likely to be V0v cells.Additionally, we demonstrate that skor1a and skor1b are expressed predominantly by glutamatergic spinal interneurons, many of which are V0v neurons. When skor1a and skor1b are knocked-down, we observe a significant reduction in the number of glutamatergic neurons and no change in the number of inhibitory neurons suggesting that these genesmay be required to specify the glutamatergic neurotransmitter phenotype of a subset of spinal neurons. In parallel studies, it was shown that evx1 and evx2, genes expressed exclusively by V0v spinal neurons, are required to specify the V0v glutamatergic phenotype. Interestingly, we show that lmx1bb, skor1a and skor1b require evx1 and evx2 for their expression. In summary, these results suggest that skor1, skor1b and lmx1bb may function downstream of evx1 and evx2 to specify and/ormaintain the glutamatergic neurotransmitter phenotype ofat least a subset of V0v neurons.
    • Deficient Emotional Self-Regulation and Adult Attention Deficit Hyperactivity Disorder: A Family Risk Analysis

      Surman, Craig B.H.; Biederman, Joseph; Spencer, Thomas; Yorks, Dayna; Miller, Carolyn A.; Petty, Carter R.; Faraone, Stephen V. (American Psychiatric Association Publishing, 2011-06)
      Objective: A growing body of research suggests that deficient emotional self-regulation (DESR) is prevalent and morbid among patients with attention deficit hyperactivity disorder (ADHD). Family studies provide a method of clarifying the co-occurrence of clinical features, but no family studies have yet addressed ADHD and DESR. Method: Participants were 83 probands with and without ADHD and 128 siblings. All were assessed for axis I DSM-IV conditions with structured diagnostic interviews. The authors defined DESR in adult probands and siblings using items from the Barkley Current Behavior Scale. Analyses tested hypotheses about the familial relationship between ADHD and DESR. Results: Siblings of ADHD probands were at elevated risk of having ADHD, irrespective of the presence or absence of DESR in the proband. The risk for DESR was elevated in siblings of ADHD plus DESR probands but not in siblings of ADHD probands. ADHD and DESR cosegregated in siblings. The risk for other psychiatric disorders was similar in siblings of the ADHD proband groups. Conclusions: The pattern of inheritance of ADHD with DESR preliminarily suggests that DESR may be a familial subtype of ADHD. Our data suggest that DESR is not an expression of other axis I DSM-IV disorders or of nonfamilial environmental factors. The authors cannot exclude contribution of non-axis-I DSM-IV disorders to risk for DESR and cannot determine whether the cosegregation of ADHD in DESR within families is a result of genes or familial environmental risk factors. Further investigation of DESR and its correlates and treatment both in and outside the context of ADHD is warranted.
    • Defining the Determinants of the Bok-IP3R Interaction and the Bok Interactome

      Richard Wojcikiewicz; Szczesniak, Laura (2021)
      Bok is a Bcl-2 protein family member that is often grouped with the pro-apoptotic family members Bax and Bak due to high sequence homology and because exogenously overexpressed Bok induces apoptosis by causing mitochondrial outer membrane permeabilization. However, the cellular roles of Bok remain unclear, as Bok KO cell lines and mice have failed to demonstrate a significant phenotype under normal conditions. Our lab discovered that Bok interacts with inositol 1,4,5-trisphosphate receptors (IP3Rs), tetrameric Ca2+ channels found in the ER membrane of mammalian cells that play an integral role in cell signaling. While other Bcl-2 family members have been reported to weakly interact with IP3Rs, the Bok-IP3R interaction is much more efficient, with essentially all cellular Bok constitutively bound to IP3Rs. We have generated full-length IP3R1 mutants that resolve the Bok-binding region to a small, unstructured loop in the cytosolic region of IP3R1 between _ helices 72 and 73. Additional bioinformatic analysis has revealed that the Bok-IP3R interaction is likely dependent upon helical and dynamic determinants within this loop. Interestingly, Bok KO cell lines demonstrate mitochondrial fragmentation and only minor changes in mitochondrial bioenergetics. We have investigated the role of Bok in mitochondrial dynamics through an in vivo proximity labeling technique known as TurboID. A TurboID-Bok fusion protein expressed in Bok KO HeLas has identified several mitochondrial fission proteins through mass spectroscopy analysis, suggesting that Bok acts at mitochondria-ER contact sites to inhibit fission, and this function may be independent of the Bok-IP3R interaction. The results provided from binding studies and proximity labeling have furthered our knowledge of the Bok-IP3R interaction and of Bok itself to better define, or re-define, the role of Bok within the cell. Understanding how and why these interactions occur will help us further understand fundamental cellular processes in health and human disease.
    • Deletion at the SLC1A1 glutamate transporter gene co-segregates with schizophrenia and bipolar schizoaffective disorder in a 5-generation family

      Myles-Worsley, Marina; Tiobech, Josepha; Browning, Sharon R.; Korn, Jeremy; Goodman, Sarah; Gentile, Karen; Melhem, Nadine; Byerley, William; Faraone, Stephen V.; Middleton, Frank A. (Wiley, 2013-01-22)
      Growing evidence for genetic overlap between schizophrenia (SCZ) and bipolar disorder (BPD) suggests that causal variants of large effect on disease risk may cross traditional diagnostic boundaries. Extended multigenerational families with both SCZ and BPD cases can be a valuable resource for discovery of shared biological pathways because they can reveal the natural evolution of the underlying genetic disruptions and their phenotypic expression. We investigated a deletion at the SLC1A1 glutamate transporter gene originally identified as a copy number variant exclusively carried by members of a 5-generation Palauan family. Using an expanded sample of 21 family members, quantitative PCR confirmed the deletion in all seven individuals with psychosis, three “obligate-carrier” parents and one unaffected sibling, while four marry-in parents were non-carriers. Linkage analysis under an autosomal dominant model generated a LOD-score of 3.64, confirming co-segregation of the deletion with psychosis. For more precise localization, we determined the approximate deletion end points using alignment of next-generation sequencing data for one affected deletion-carrier and then designed PCR amplicons to span the entire deletion locus. These probes established that the deletion spans 84,298 bp, thus eliminating the entire promoter, the transcription start site, and the first 59 amino acids of the protein, including the first transmembrane Na2+/dicarboxylate symporter domain, one of the domains that perform the glutamate transport action. Discovery of this functionally relevant SLC1A1 mutation and its co-segregation with psychosis in an extended multigenerational pedigree provides further support for the important role played by glutamatergic transmission in the pathophysiology of psychotic disorders. © 2013 Wiley Periodicals, Inc.
    • Design and Characterization of Proteins Rationally Engineered to Domain Swap by Mutually Exclusive Folding

      Loh, Stewart; Karchin, Joshua Michael (2016)
      Domain swapping is a mechanism for proteins to form dimers and higher order oligomers through the exchange of a section of their 3D structures. The backbone peptides of domain swapped oligomers are intertwined, but their 3D structures remain identical to their monomeric state, except for where they cross-over, termed a hinged region. We have developed a technique to engineer domain swapping interfaces with mutually exclusive folding (MEF). MEF achieves this by inserting a ‘lever’ protein into the surface loops of a host ‘target’ protein to form a target-lever fusion. This target-leveris conformationally strained with the lever and the target in a thermodynamic tug-of-war. When the lever is folded, the long distance between its N- and C-termini stretches apart the target and splits it in half. Conversely, when the target is folded, the short length of the loop where the lever was inserted compresses the lever and unfolds it. Domain swapping provides an escape from this tug-of-war as it allows the split target to refold and bypass the conformational strain. Because the lever is external to the target, adjusting the stability of the lever, through well-established thermodynamic principles, allows the propensity for domain swapping to be modulated without affecting the binding interface. This enables the design of “triggerable” levers which can reversibly induce domain swapping in response to a signal. Further, we can use domain swapping to turn the function of a target domain on and off. Two target-lever constructs are created with functional mutants in the target domain, one N-terminal to the lever and the other one C-terminal to the lever. Individually, both of these mutants are inactive, however if they are mixed and allowed to domain swap, then up to half of the target domains can swap out the functional mutations into the native active form. This bimolecular system in combination with induced domain swapping enables the design of modular bioswitches and biosensors.