Russell Matthews; Sinha, Ashis (2021)
      The complex organization and trajectory of development of the central nervous system (CNS) depends not only on cell-cell interactions but also on interactions of cells with the extracellular environment. The extracellular environment in the CNS contains an organized network of proteins, glycans and glycoproteins and comprises what is called the CNS extracellular matrix (ECM). Components of this ECM are dynamically regulated not just during development but are also involved in various neurobiological processes in the adult. They are implicated in normal nervous system physiology as well as in nervous system disease and pathology. A complete understanding of the CNS therefore, requires an understanding of the composition, structure and function of the neural ECM also. Our laboratory focuses on a specialized substructure of the neural ECM, called perineuronal nets (PNNs). PNNs are conspicuous structures within the neural ECM and are thought to be key regulators of neuronal plasticity. Traditionally their role has been demonstrated in regulating forms of plasticity seen during development, but recent work has implicated PNNs in other forms of learning and plasticity across various brain regions as well. Interest in these structures has been further peaked by studies linking their alterations to a variety of neurological and neuropsychiatric diseases such as Alzheimer's disease and schizophrenia. However, despite this growing interest in PNNs, the mechanisms by which they modulate neural functions are poorly understood. The limited mechanistic understanding of PNN function is derived primarily from the fact that there are no existing models, tools or techniques that specifically target them without also disrupting the surrounding neural ECM. Therefore, a rigorous investigation of PNN function to date has not been possible. Our inability to specifically target PNNs is driven by an incomplete of understanding of their molecular composition and structure. While PNNs comprise of many known ECM components which are broadly expressed in the CNS ECM, PNNs appear clearly distinct from their surroundings. They are highly ordered and stable and show a regular organization and geometry not present in the diffuse neural ECM. The exact molecular mechanisms by which various PNN components come together and aggregate on the cell surface to form these structures however, is not iii clearly known. The primary goal of our laboratory has therefore been to determine the molecular structure, composition and formation of PNNs. Through our work described in chapters 2 and 3 of this thesis, we were able to develop a new model of PNN structure. In our proposed model, PNN components are bound to the cell surface by two distinct types of interactions, one dependent on the classical HA scaffold of PNNs and the other mediated by a complex formed by the ECM glycoprotein tenascin-R (TNR) and the chondroitin sulfate proteoglycan receptor protein tyrosine phosphatase zeta (RPTPz). Our work also allowed us to provide evidence that PNN components are immobilized on the neuronal surface by a GPI-linked mechanism. We identify the GPI-linked protein contactin-1 (CNTN1) as a key receptor molecule for PNNs. To our knowledge, this is the first ever identified receptor for PNNs. We feel that our findings presented here give us important insight into PNN structure and represent the initial important steps in understanding the formation of this unique ECM subcompartment.

      Knox, Barry; ZHUO, XINMING (2013)
      Rod photoreceptors are a group of specialized retinal neurons that convert light into a neuronal signal in low light condition. The phototransduction function of rodsrequires expression of a group of rod genes. The homeostasis of these genes is primarily regulated by a photoreceptor regulatory network, which contains two major retina-specific transcription factors, neural retina leucine zipper (Nrl) and cone-rod homeobox(Crx). Nrl and Crx synergistically activate the expression of several phototransduction genes, most notably rhodopsin. Base on the studies done in cell culture, the synergy is theconsequence of interaction of Nrl and Crx. However, the interaction of Nrl and Crx has not been studied in live rods. The goal of thesis is to develop methods that can be used for studying Nrl and Crx interaction in live rods.In order to study Nrl and Crx in live rods without altering cell fate and inducing cell degeneration, I developed a novel inducible system, G3U, which can regulate gene expression in live rods. In this chapter, we investigated the characters of G3U by using rhodopsin-mCherry as a reporter and monitoring the induction response in transgenic Xenopus. The results of live rod imaging suggest that the inducible system has negligible background expression before induction and significant fold increase of expression after induction. Moreover, the induction response of G3U is reproducible in rods. These findings suggest that G3U system is a good candidate for expressing Nrl and Crx temporally in rods. In the second part of my thesis, I developed a flow cytometry based FRET method, FC-FRET, to study Nrl and Crx interaction in live cells. This method allows non-invasively analysis of protein-protein interaction in large population of live cells in a very short time. Furthermore, researchers will be able to analyze the concentration effect of FRET conveniently. In this study, I investigated the orientation of Nrl-Nrl, Crx-Crx and Nrl-Crx interactions. Our studies revealed that the Nrl-Nrl homodimer has a head-to-head and tail-to-tai l conformation. Both the Crx-Crx and the Nrl-Crx dimers have a head-to-head conformation in interacting complex. I also performed structure-function studies on both Nrl and Crx and classified the role of their different domains in the interactions. In addition to the known Nrl basic leucine zipper domain (b-ZIP) and Crx homeobox domain (HD), we found that the Nrl extended homology domain (EHD) plays an important role in the Nrl-Crx interaction. Two methods presented in this thesis are my major achievement during my graduate studies. The G3U inducible can be used to generate transgenic animals carrying inducible Nrl and Crx in rods. These transgenic animals allow researchers to study the interaction of Nrl and Crx in live rods by FC-FRET assay.

      Viczian, Andrea; Keshvani, Caezaan (2013)
      Age related macular degeneration results in loss ofconephotoreceptors. Studies have not been able to efficientlytransplant cone cells, possiblydue to their limited numbersand lack of information about their development in the mammalian retina.Our lab has discoveredthat BMP signal inhibition is important for eye developmentin the frogas well as generating retinal cone photoreceptorsin mouse embryonic stem cell cultures. The frog, Xenopus laevis,can grow eyeswithin a few days; it is also amenable to transplantation and genetic alteration. In this study, two small molecule BMP inhibitors, LDN193189 and Dorsomorphin, causedshortened tails(dorsalized) phenotypein Xenopusembryos as well asexpansionofthe neural plate in neural stage embryos. This suggests that these chemical inhibitors can be used in place of the standard BMP antagonist, Noggin, in cell culture experiments. Mouse embryonic stem cell cultures treated with Noggin have been used to generate retinal progenitors that generate cone photoreceptorsin our lab. In order to further study cones indetail,we needed to enrich the population of cone photoreceptors from retinal progenitors by marking these cells in-­‐vitro. We generated stable mouse embryonic stem cells expressing a promoter that drives expression in rod/cone progenitor cells upstream from the mCherry fluorescent protein. This construct also contained aubiquitous promoterdriving an antibiotic resistance genefor antibiotic selection. In future studies, these stable ES celllines could be used to differentiate into rod/cone progenitors selected specifically by FAC sorting. Small molecule BMP inhibitors could be used in place of Noggin and analyzed in the generation of conecells.
    • Substance Use among ADHD Adults: Implications of Late Onset and Subthreshold Diagnoses

      Faraone, Stephen V.; Wilens, Timothy E.; Petty, Carter; Antshel, Kevin; Spencer, Thomas; Biederman, Joseph (Wiley, 2007-01)
      Diagnosing ADHD in adults is difficult when the diagnostician cannot establish an onset prior to the DSM-IV criterion of age seven or if the number of symptoms does not achieve the DSM threshold for diagnosis. These diagnostic issues are an even larger concern for clinicians faced with adults with substance use disorders (SUD). The present study compared four groups of adults: full ADHD subjects who met all DSM-IV criteria for childhood onset ADHD, late onset ADHD subjects who met all criteria except the age at onset criterion, subthreshold ADHD subjects who did not meet full symptom criteria, and nonADHD subjects who did not meet any of the above criteria. Diagnoses were by the Structured Clinical Interview for DSM-IV, and the Drug Use Severity Index (DUSI) was used for self-report of substance use. Cigarette and marijuana use was significantly greater in all ADHD groups relative to non-ADHD controls. Although usage rates of other drugs failed to reach significance, the ADHD groups were more likely to have used each drug (except alcohol) compared with the non-ADHD group. The late onset and full ADHD groups were more likely to have endorsed ever having a problem due to use of cigarettes, alcohol, or marijuana and reported more trouble resisting use of drugs or alcohol. The full ADHD group was more likely than the other groups to have reported ‘‘getting high’’ as their reason for using their preferred drug. Adults with ADHD have elevated rates of substance use and related impairment. Data about late onset ADHD provides further support for the idea that the DSM-IV age at onset criterion is too stringent. In contrast, subthreshold ADHD seems to be a milder form of the disorder, or perhaps a heterogeneous group of true ADHD cases and false positives.
    • Substance Use Disorders in High-Risk Adolescent Offspring

      Milberger, Stephen V. Faraone, Jose, Sharon (Wiley, 1999-01)
      Objective: To examine the risk for substance use disorders (SUD) in offspring of SUD parents who were not selected due to referral to SUD treatment centers. Method: The original sample was ascertained through two groups of index children: 140 ADHD probands and 120 non-ADHD comparison probands. These groups had 174 and 129 biological siblings and 279 and 240 parents, respectively. Results: We found that: 1) parental SUD was associated with SUD and all SUD subtypes in the offspring; 2) parental alcohol use disorders were associated with alcohol use disorders in the offspring as well as co-occurring alcohol and drug use disorders but not drug use disorders alone in the offspring; and 3) drug use disorders in the parents were associated with drug use disorders but not alcohol use disorders in the offspring. Conclusions: These findings suggest that alcoholism and drug abuse may breed true from parents to their offspring, but further work with larger samples is needed to confirm this idea. Our findings also suggest a possible common diathesis that is expressed as comorbid alcohol and drug use in the offspring of alcoholic parents. If confirmed, these findings may be useful for the development of preventive and early intervention strategies for adolescents at high risk for SUD based on parental history of SUD.
    • T Cell Factor-1 (TCF-1) Regulates Mature Alloactivated T Cells to Separate GVHD From GVL

      Mobin Karimi; Harris, Rebecca (2021)
      Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment used for patients with cancer or other hematological malignancies. However, widespread use of this treatment is hindered by development of graft-versus-host disease (GVHD), a life-threatening complication of allo-HSCT. Mature donor T cells in the graft mediate GVHD, but also help kill residual malignant cells in the patient by the graft-versus-leukemia (GVL) effect. Depletion of mature T cells from the graft eliminates this beneficial anti-tumor response. Mature T cells are also needed for proper stem cell engraftment. Therefore, current work has focused on how to modulate T cell signaling and function to separate GVHD from GVL. T Cell Factor-1 (TCF-1) is a T cell developmental transcription factor that is also important in some contexts for T cell activation. The role of TCF-1 in alloactivated mature T cells is completely unknown. To examine the role of TCF-1 in this context, a mouse model of allo-HSCT leading to GVHD/GVL was used to study T cells from mice with a T cell-specific deletion of TCF-1. This work showed that loss of TCF-1 separates GVHD from GVL, with reduced disease severity and persistence yet maintained GVL effects. TCF-1 affects alloactivated T cell phenotypes and suppressive profiles, as well as the major T cell functions (proliferation, migration, and cytokine/cytotoxic mediator production). TCF-1 also controls alloactivated T cell survival, apoptosis, and gene expression programs. The regulation of these functions and programs by TCF-1 is distinct in CD4 versus CD8 T cells. TCF-1 also controls two unique T cell subsets - stem-like CXCR5+ CD8+ T cells, and CD25- noncanonical Tregs. Therefore, TCF-1, or these two unique T cell types, may be a therapeutic target to improve allo-HSCT outcomes by separating GVHD from GVL effects. Expansion of CD25- Tregs during TCF-1 deficiency may also be useful for treatment of other T cell-mediated disorders as well.
    • Targeting SHIP paralogs to promote microglial effector function in the CNS

      Thomas, Stephen J.; Pedicone, Chiara (2022-06)
      The two SH2-containing inositol 5'-phosphatases , SHIP1 (INPP5D) and SHIP2 (INPPL1), play an essential role in modulation of cellular signaling by transforming the PI3K product PI(3,4,5)P3 into PI(3,4)P2. PI3K signaling triggers activation of downstream signaling cascades that drive survival, effector functions, differentiation, and proliferation. SHIP1 can also mask the cytoplasmic tails of key receptors or their adaptor proteins such as DAP12, thus preventing PI3K recruitment to Trem2, a critical receptor for microglial function. Several GWAS studies correlated single nucleotide polymorphisms (SNPs) in INPP5D with Alzheimer's Disease (AD). However, it remains unclear whether these SNPs are deleterious or protective in AD and how they alter SHIP1 protein expression. SHIP2 overexpression has also been correlated with AD, suggesting that both SHIP1 and SHIP2 might be therapeutic targets. To study how SHIP1 and SHIP2 modulate microglial functions we used small molecule inhibitors and agonists of these enzymes. In our initial study we found that both SHIP paralogs are expressed in murine microglia and that Pan- SHIP1/2 inhibition increases lysosomal size and enhances microglial phagocytosis of Ab1-42 fibrils and dead neurons using both flow cytometry and confocal microscopy. Our lead Pan-SHIP1/2 inhibitor, K161, showed Blood Brain Barrier penetration as detected in the cerebral cortex of treated mice with mass spectrometry. K161 treatment of WT mice showed no difference in microglial frequency or lysosomal content in vivo; however, we observed a significant 2 increase in Ab1-42 and dead neurons phagocytosis ex vivo in microglia in K161- treated mice versus controls. Subsequently, we discovered a novel and highly potent SHIP1 selective agonist (K306) via artificial intelligence guided computational screening. We found that K306 can reduce the release of inflammatory cytokines in macrophages and microglial cells stimulated with LPS or Ab1-42. Interestingly, K306 didn't alter microglial phagocytic uptake of cargo, but did promote degradation of phagocytosed lipid-laden cargo - defining a novel role of SHIP1 in degradation of lipid cargo in microglia. These results highlight the importance of SHIP1 and SHIP2 in microglial biology and their modulation as therapeutics in different stages of neurodegenerative disease where microglia play a major role, such as AD.
    • Targeting wild-type and mutant p53 for cancer treatment

      Stewart N Loh; Blayney, Alan John (2021)
    • Targetingof PIM1 KinaseinMyeloproliferative NeoplasmsInduced by JAK2V617F

      Mohi, Golam; Stuver, Matthew (2017)
      Myeloproliferative neoplasms (MPNs) arestem cell-derivedblood disorders. The most common mutation found in MPN patients is the JAK2V617Fmutation. JAK2 is anon-receptor tyrosine kinase involved in STAT signaling. The JAK2V617F mutation is asingle amino acid substitution of a phenylalanine for valine, whichcauses JAK2 to be constitutively activated. This mutation can cause ahematopoietic transformation. Eventuallythis transformationcan lead to the development of one of thethree different Philadelphia-negative MPN diseases: Polycythemia Vera (PV), Essential Thrombocythemia (ET), and Primary Myelofibrosis (PMF). The JAK2V617F mutationhas been identified in 95% PVpatients,and 50-60% ofETand PMF patients.A JAK1/2 inhibitor (ruxolitinib) has been approved for MF and PV patients and,though it provides initial benefits, it is not effective enough to causelong-termremission in patients. This creates a critical need to identify new therapeutic targets for MPN patients. We found that PIM1 levels were significantly increased inMPN patients, as well asour JAK2V617F mouse modelof MPN.We observedthatknockdown of PIM1 caused a significant decrease in proliferationof JAK2V617F expressing cells. We also found that PIM1 knockdownhad no effect on the proliferation of hematopoietic cells not expressing JAK2V617F, leading us to believe PIM1 is only required in JAK2V617F mediated proliferation. Pharmacological inhibition of PIM kinases,using TP-3654,(kindly provided by Tolero pharmaceuticals)also led to a significant decrease in proliferation of JAK2V617F-expressing cells, but had no effect on cellslacking the mutation. We also found thatthePIM inhibitor,TP-3654,workssynergistically with ruxolitinibto achieve an even greater decrease in proliferation. We found that using the combination of ruxolitiniband TP-3654,we could use both drugs at lower concentrations andachieve an even greater decrease in proliferation and an increase apoptosis. Furthermore,we found that inhibition of PIM kinasesusing TP-3654can resensitize ruxolitinib-resistant cells to ruxolitinibtreatment.These important findingsshow that PIM1 plays animportantrolein the proliferation of hematopoietic cells expressing the JAK2V617F mutation, but is dispensable for the maintenance of cells lacking the mutation. We also found that targeting PIM kinases with TP-3654,significantly decreasedthe proliferation, and increaseapoptosisactivationof JAK2V617Fexpressing cells. We also showedthat TP-3654 and ruxolitinibcan work synergistically. Lastly, we showed that inhibition of PIM kinases,using TP-3654,caused ruxolitinib-resistant cells tobecome resensitized toruxolitinib. These findings helpedus come to the conclusionthatPIM1 kinase, is an importanttherapeutictargetin JAK2V617F-induced MPNs.

      King, Christine; Endy, Timothy; Barbachano-Guerrero, Arturo (2020)
      Dengue virus (DENV) causes an estimated 390 million infections worldwide annually, with severe forms of disease marked by vascular leakage and an over reactive inflammatory response. Endothelial cells (EC) are directly responsible for vascular homeostasis and are highly responsive to circulating mediators but are not commonly infected. Mast cells (MC) are potent cells of the innate immune system that play an important role in EC biology and inflammatory responses. DENV encodes 10 proteins; with only one, the non-structural protein 1 (NS1), secreted from infected cells and accumulating in the blood of patients.NS1 has been implicated in the pathogenesis of vascular permeability, but the mechanism is not completely understood. Using a complementary array of in vitroassays and disease relevant ECs and MCs, we described the possible roles for NS1 in dengue disease pathogenesis. Using microscopy and immunoblotting we observed that ECs internalize NS1 into endosomes, where it accumulates and is degraded overtime. Transcriptome and pathway analysis defined changes in global gene expression in ECs that are associated with cell dysfunction. We observed that NS1 induced an increase in multicellular rearrangements and a decrease in barrier function in ECs. We demonstrated that NS1-dependent activation of the p38 MAPK pathway controls the changes in EC permeability in vitro. Further, we discovered iiithat ECs and MCs respond to NS1 by secreting a specific array of proinflammatory cytokines and chemokines that may contribute to the cytokine storm in dengue disease. Finally, we found that NS1 internalization can mediate the uptake of bound antibodies into ECs. Together, these results suggest a vasoactive and proinflammatory role for DENV NS1 that may participate in the development of severe symptoms in dengue disease. The observed functions of NS1 could lead to the discovery of new therapeutic targets in dengue disease.

      Bourboulia, Dimitra; Sánchez Pozo, Javier (2018)
      Matrix metalloproteinases (MMPs) are secreted zinc-dependent endopeptidases that are involved in many extracellular biological processes due to their matrix-degrading function. The majority of theseenzymes are released intothe extracellular space in their inactive form and require activation. The tissue inhibitors of metalloproteinases (TIMPs) are also secreted proteins and mainly function to inhibit all members of the MMP family. Interestingly, TIMP-2 also participates in the activationprocessof proMMP-2. Although the interaction between TIMP-2 and proMMP-2 has been known for decades, the molecular signal that triggersthis association has only recently beendetermined. Studies in our lab haveshown that TIMP-2 is tyrosine phosphorylatedby the c-Srctyrosinekinase. Also, phosphorylation of TIMP-2 Tyr90is essential for its interaction with proMMP-2in vivo. Our hypothesis is that c-Src-mediated TIMP-2 phosphorylation happens outside the cell. Here, wedemonstratethat TIMP-2 and c-Src are secreted through different secretory pathways and that TIMP-2 phosphorylation takes place in the extracellular space. Our workalso showsthatextracellularc-Srcisactive, reinforcing the fact that phosphorylation can happen extracellularly. We also hypothesize that extracellular c-Src plays a critical role in facilitating TIMP-2:proMMP-2 interaction. We first confirmed thatTIMP-2 and proMMP-2 endogenously interact only in cells containing endogenous c-Src. This interaction,as well as TIMP-2 phosphorylation,was blocked by treating cells with acustom-made anti-c-Src polyclonal antibody (pAb)that targets amino acids 84-110. We also showthat ananti-c-Src antibody that targets the first 79 amino acids does not inhibit TIMP-2 phosphorylation and interaction with proMMP-2. Therefore, since TIMP-2:proMMP-2 complex formation promotes proMMP-2 activation, we hypothesize that c-Src is an essential player in this process. Our data showsthatthe non-phosphorylatable TIMP-2Tyr90mutant does not promote proMMP-2 activation. Furthermore, pretreatment with the anti-c-Src pAbblockedTIMP-2-mediated proMMP-2 activation, whereasthe anti-c-Src mAb6 did not affect proMMP-2 activation. Overall, these findings provide further evidence that secreted c-Src-mediated TIMP-2 phosphorylation occurs in the extracellular space, where thesecretedkinase is also active. Moreover, c-Src is essential for TIMP-2:proMMP-2 complex formation as well as proMMP-2 activation.
    • A trancriptomics based approach reveals the functional consequences of RNase MRP RNA mutations in yeast.

      Schmitt, Mark; Shafiuddin, Md (2018)
      RNase MRP is a eukaryotic ribonucleoprotein complex involved in multiple cellular functions that includes ribosomal RNA processing, primer generation for mitochondrial DNA replication and degradation of cell cycle related mRNAs. In Saccharomyces cerevisiae, the RNA component of RNase MRP is encoded by NME1. We have performed random deletion mutagenesis of RNase MRP RNA gene and isolated a mutation, nme1-91, that causes temperature sensitive growth defect on glycerol media. RNA analysis of nme1-91 showed that this mutant is mildly deficient in the 5.8S rRNA processing function of RNase MRP. Growth analysis and northern blotting of RNase MRP RNA mutations generated based on nme1-91 allele suggested that 3’-end nucleotide sequences of the nme1-91 allele contribute to its phenotype. Highcopy suppression screen identified tRNA modification gene NCS6 as a suppressor of nme1-91. Additionally, primary mode of suppression by NCS6 was found to be non-mitochondrial since NCS6 partially suppressed the nme1-91 phenotype on fermentable carbon source. Strains carrying a deletion of NCS6 in combination with nme1-91 showed a synthetic sick phenotype. Polysome profile analysis of nme1-91 revealed that 80S monosomal fraction accumulates in this mutant. Differential gene expression analysis of nme1-91 by RNAseq indicated that rRNA processing and cell cycle related genes become mis-regulated due to this mutation. A similar high-throughput sequencing based approach was also employed to investigate the transcriptional basis of positive genetic interactions between components of RNase MRP and nonsense-mediated decay pathway. A yeast strain bearing the nme1-P6 mutation in the RNA component of RNase MRP exhibits temperature-sensitive growth defect. This phenotype can be suppressed by deletion of NMD components. Differential gene expression analysis identified several mis-regulated biological processes in nme1-P6 and Δupf1 strains. Comparative transcriptomic analysis suggested that suppression of nme1-P6 phenotype by Δupf1 is accompanied by large shift in gene expression pattern towards Δupf1 strain. Moreover, the majority of direct targets of NMD were not down-regulated in nme1-P6 indicating that the effect of NMD on nme1-P6 might be due to increased degradation on mRNAs that are not targeted by NMD in normal conditions. Taken together, these results show that mutations of RNase MRP RNA can modulate diverse biological processes.
    • Transcriptome-wide gene expression in a rat model of attention deficit hyperactivity disorder symptoms: Rats developmentally exposed to polychlorinated biphenyls

      Sazonova, Nadezhda A.; DasBanerjee, Tania; Middleton, Frank A.; Gowtham, Sriharsha; Schuckers, Stephanie; Faraone, Stephen V. (Wiley, 2011-09-14)
      Polychlorinated biphenyls (PCB) exposure in rodents provides a useful model for the symptoms of Attention deficit hyperactivity disorder (ADHD). The goal of this study is to identify genes whose expression levels are altered in response to PCB exposure. The brains from 48 rats separated into two age groups of 24 animals each (4 males and 4 females for each PCB exposure level (control, PCB utero, and PCB lactational)) were harvested at postnatal days 23 and 35, respectively. The RNA was isolated from three brain regions of interest and was analyzed for differences in expression of a set of 27,342 transcripts. Two hundred seventy-nine transcripts showed significant differential expression due to PCB exposure mostly due to the difference between PCB lactational and control groups. The cluster analysis applied to these transcripts revealed that significant changes in gene expression levels in PFC area due to PCB lactational exposure. Our pathway analyses implicated 27 significant canonical pathways and 38 significant functional pathways. Our transcriptomewide analysis of the effects of PCB exposure shows that the expression of many genes is dysregulated by lactational PCB exposure, but not gestational exposure and has highlighted biological pathways that might mediate the effects of PCB exposure on ADHD-like behaviors seen in exposed animals. Our work should further motivate studies of fatty acids in ADHD, and further suggests that another potentially druggable pathway, oxidative stress,may play a role in PCB inducedADHD behaviors
    • Traumatic Brain Injury and Schizophrenia in Members of Schizophrenia and Bipolar Disorder Pedigrees

      Malaspina, Dolores; Goetz, Raymond R.; Friedman, Jill Harkavy; Kaufmann, Charles A.; Faraone, Stephen V.; Tsuang, Ming; Cloninger, C. Robert; Nurnberger, John I.; Blehar, Mary C. (American Psychiatric Association Publishing, 2001-03)
      Objective: Schizophrenia following a traumatic brain injury could be a phenocopy of genetic schizophrenia or the consequence of a gene-environment interaction. Alternatively, traumatic brain injury and schizophrenia could be spuriously associated if those who are predisposed to develop schizophrenia have greater amounts of trauma for other reasons. The authors investigated the relationship between traumatic brain injury and psychiatric diagnoses in a large group of subjects from families with at least two biologically related first-degree relatives with schizophrenia, schizoaffective disorder, or bipolar disorder. Method: The Diagnostic Interview for Genetic Studies was used to determine history of traumatic brain injury and diagnosis for 1,275 members of multiplex bipolar disorder pedigrees and 565 members of multiplex schizophrenia pedigrees. Results: Rates of traumatic brain injury were significantly higher for those with a diagnosis of schizophrenia, bipolar disorder, and depression than for those with no mental illness. However, multivariate analysis of within-pedigree data showed that mental illness was related to traumatic brain injury only in the schizophrenia pedigrees. Independent of diagnoses, family members of those with schizophrenia were more likely to have had traumatic brain injury than were members of the bipolar disorder pedigrees. The members of the schizophrenia pedigrees also failed to show the gender difference for traumatic brain injury (more common in men than in women) that was expected and was present in the bipolar disorder pedigrees. Subjects with a schizophrenia diagnosis who were members of the bipolar disorder pedigrees (and thus had less genetic vulnerability to schizophrenia) were less likely to have had traumatic brain injury (4.5%) than were subjects with schizophrenia who were members of the schizophrenia pedigrees (and who had greater genetic vulnerability to schizophrenia) (19.6%). Conclusions: Members of the schizophrenia pedigrees, even those without a schizophrenia diagnosis, had greater exposure to traumatic brain injury compared to members of the bipolar disorder pedigrees. Within the schizophrenia pedigrees, traumatic brain injury was associated with a greater risk of schizophrenia, consistent with synergistic effects between genetic vulnerability for schizophrenia and traumatic brain injury. Posttraumatic-braininjury schizophrenia in multiplex schizophrenia pedigrees does not appear to be a phenocopy of the genetic disorder.
    • Treatment of nonpsychotic relatives of patients with schizophrenia: Six case studies

      Tsuang, Ming T.; Stone, William S.; Tarbox, Sarah I.; Faraone, Stephen V. (Wiley, 2002-11-27)
      There is growing support for the notion that the genetic liability for schizophrenia could be manifested in brain dysfunction, even without the full manifestations of schizophrenia [Meehl, 1962, 1989; Seidman, 1997; Faraone et al., 2001]. This liability is characterized clinically by neurologic, neurobiological, psychiatric, neuropsychological, and psychosocial impairments in nonpsychotic, first-degree relatives of people with schizophrenia and includes eye tracking dysfunction [Levy et al., 1994], allusive thinking [Catts et al., 1993], neurologic signs [Erlenmeyer-Kimling et al., 1982], biochemical abnormalities [Callicott et al., 1998], char acteristic auditory evoked potentials [Friedman and Squires-Wheeler, 1994], neuroimaging assessed brain abnormalities [Seidman et al., 1997], and neuropsycho logical impairment [Kremen et al., 1994]. Paul Meehl introduced the term ‘‘schizotaxia’’ in 1962 to describe the genetic predisposition to schizophrenia [Meehl, 1962], and we have modified the concept to take account of subsequent research [Faraone et al., 2000]. The concept of schizotaxia raises at least three fundamental issues: 1) What is the conceptual basis of schizotaxia? 2) Is it a valid syndrome? and 3) perhaps most importantly from the point of view of the eventual prevention of schizo phrenia, is it treatable? In this paper, we review the model of schizotaxia by focusing first on its nature and extent. We then describe preliminary research criteria for its diagnosis in nonpsychotic relatives of schizo phrenic patients, followed by a presentation of our initial attempts to treat schizotaxia. Finally, prospects for the future focus on the need to validate the proposed syndrome further and on the clinical implications of treating schizotaxia.

      Huang, Ying; Liu, Renyan (2017)
      Monoglyceride lipase (MGL) is a serine hydrolase that hydrolyzes 2-monoglycerides and produces fatty acid and glycerol. Our previous studies showed that there was MGL deficiency in the majority of human lung, breast, and colorectal cancer tissues as compared with normal tissues. Further studies suggested that MGL was a potential tumor-suppressor in the development of colorectal cancer. However, paradoxical findings about the role of MGL in tumorigenesis have been reported. It is therefore important to further elucidate the function of MGL in tumorigenesis. To that end, we generated MGL-knockout mouse and found that MGL knockout led to tumor formation in multiple organs/tissues of mice. Particularly, the major findings were lung adenocarcinomas. In cultured cells, MGL deletion enhanced cell proliferation and induced cellular transformation. Further molecular studies demonstrated that MGL suppressed EGFR signaling, NF-κB activity, and COX-2 expression. Deficiency of MGL may lead to over-activation of EGFR, NF-κB, and COX-2, and therefore contribute to tumorigenesis. We also found that MGL over-expression induced remarkable cancer cell apoptosis, and increased cleavage of caspase-8, caspase-9, caspase-3 and PARP. MGLinduced apoptosis thus involves both the intrinsic mitochondria-mediated and extrinsic death receptor-initiated apoptosis pathways. Most importantly, our data indicated that MGL interacted with a potent inhibitor of apoptosis, XIAP, and significantly reduced XIAP protein stability, which may unleash caspase-9 and caspase-3 from XIAP inhibition and thereby promote apoptosis. Some additional findings about MGL showed that MGL localization to lipid droplets was important for its regulation of cell growth and pro-tumorigenic signaling while MGL’s lipase activity is dispensable for these effects. We identified Asp-115 (D115) of MGL as the most important amino acid residue in mediating MGL localization to lipid droplets. We also found that MGL deficiency promotes lipid droplet formation and cellular lipid accumulation, which potentially promotes cancer cell survival under stressful conditions. Overall, our in vitro and in vivo data strongly support the notion that MGL is a tumor suppressor. The molecular findings about MGL may have revealed certain targets for personalized cancer therapy in the context of MGL deficiency and they also implicate potential roles of MGL in inflammation, immunity, and metabolism.

      Mollapour, Mehdi; Woodford, Mark R. (2021)
      Folliculin (FLCN) is tumor suppressor protein whose function remains a topic of debate. Germline mutations in FLCN predispose affected individuals to develop Birt-Hogg-Dubé syndrome, which is characterized by facial fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax, and renal cell carcinoma. These kidney tumors exhibit an elevated glycolytic phenotype even in the presence of oxygen, an observation commonly known as the “Warburg effect.” This phenomenon is driven by the activity of lactate dehydrogenase-A (LDHA), the enzyme responsible for the interconversion of pyruvate and lactate in the terminal step of glycolysis. Our work herein shows that FLCN is a specific intracellular inhibitor of LDHA. Biochemical and biophysical analyses mapped the interaction and inhibition of LDHA activity to an unstructured loop in FLCN positioned between the amino and carboxy-terminal domains. Characterization of a minimal 10-amino acid FLCN-derived peptide demonstrated that it was sufficient to both bind and inhibit LDHA activity in vitro. Further, treatment of FLCN-deficient cells with this FLCN-derived peptide is sufficient to suppress glycolysis. Interestingly, evaluated cancer cell lines derived from solid tumors of the lung, breast, prostate, bladder, and colon also demonstrate dysregulation of LDHA activity and dissociation of FLCN-LDHA interaction. Previous work has shown that inhibition of LDHA in cancer cells leads to apoptosis. Accordingly, treatment of these cell lines with the FLCN-peptide results in apoptosis, suggesting a potential therapeutic intervention. Taken together, inhibition of LDHA by the tumor suppressor FLCN provides a mechanistic explanation for the endogenous regulation of glycolysis.

      Mohi, Golam; JOBE, FATOUMATA (2016)
      Myeloproliferative neoplasms (MPNs) are a class of clonally-derived hematologic malignancies characterized by uncontrolled proliferation of myeloid lineage cells. Theyare classified into Philadelphiachromosome-positive (Ph+)MPNs, consisting of chronic myelogenous leukemia (CML), and Philadelphiachromosome-negative (Ph-)MPNs, consisting of polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis(PMF).The JAK2V617F mutation is the most common abnormality in Ph-MPNs, occurring in ~95% of PV patients, 55% of ET patients and 65% of PMF patients. JAK2V617F mutation results in constitutive activation of the JAK2 tyrosine kinase. Deletion of chromosome 20q (20q-) is a common chromosomal abnormality in myeloid neoplasms, including about 24%of MFcases. The 20q-lesion can coexist with JAK2V617Fmutation in MPN and MDS/MPN. The PTPN1gene is located on human chromosome 20q, within the commonly deleted region. PTPN1 is a tyrosine phosphatase and a known negative regulator of JAK-STAT signaling. The role of PTPN1 loss in the pathogenesis of MPNs and the mechanism by which loss of PTPN1 might contribute to various MPN phenotypes remains elusive. The goalsof this dissertation were to determine the effects of PTPN1 deficiency alone and in JAK2V617F-induced MPNs in vivo. To determine the mechanism by which PTPN1 mediates its tumor suppressor function using hematopoietic cells andassessment of PTPN1 status in 20q-MPN patients.Using conditional knock-out PTPN1 mouse model, we show that deletion of PTPN1 causes an MPN-like phenotype, characterized by increased WBC and NE counts and splenomegaly, compared to control mice. We also show that loss of PTPN1 causesfibrosis in older mice. PTPN1 knockdown significantly increased cell proliferation and activation of JAK2, MAPK and AKT signaling, whereas over expression in JAK2V617F-expressing cells attenuated cytokine-independent cell proliferation and signaling. Our data revealed a cooperative effect between PTPN1 deficiency and JAK2V617F expression in mice as shown by enhanced severity of theMPN phenotype and transformation to MF. Cell autonomous BMT revealed that the effects of PTPN1 deficiency are cell autonomous.Taken together, our results suggest a novel tumor suppressor function for PTPN1 in MPNs.
    • A Twin Study of Sexual Behavior in Men

      Lyons, Michael J.; Koenen, Karestan C.; Buchting, Francisco; Meyer, Joanne M.; Eaves, Lindon; Toomey, Rosemary; Eisen, Seth A.; Goldberg, Jack; Faraone, Stephen V.; Ban, Rachel J.; et al. (Springer Science and Business Media LLC, 2004-04)
      The role of genetic and environmental influences on age of initiation of first sexual relations and engaging in sexual activity with multiple partners (10 or more partners in 1 year) was investigated in male twins (N = 6, 744) from the Vietnam Era Twin Registry. Individual differences in both types of sexual behaviors were heritable, but only age of onset of sexual relations was significantly influenced by the environment shared by the twins. There was a moderate negative correlation between age of initiation of sexual relations and the multiple partners variable; initiating sexual relations earlier was associated with a higher probability of having multiple partners. The additive genetic influence on age of initiation also influenced the multiple partners variable. The substantial unique environmental influences on each variable were uncorrelated with each other. The data suggest that the observed association between age of initiation of sexual relations and having multiple partners is due to genetic influences common to both behaviors.