• 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.
    • 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.
    • THE ROLE OF DENGUE VIRUS NON-STRUCTURAL PROTEIN 1 IN DISEASE PATHOGENESIS

      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.
    • TIMP-2 PHOSPHORYLATION BY EXTRACELLULAR c-SRC REGULATES proMMP-2 ACTIVATION

      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.
    • THE TUMOR SUPPRESSIVE ROLE OF MONOGLYCERIDE LIPASE IN LUNG CANCER

      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.
    • THE TUMOR SUPPRESSOR FOLLICULIN REGULATES GLYCOLYSIS BY SPECIFICALLY BINDING AND INHIBITING LACTATE DEHYDROGENASE-A

      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.
    • A TUMOR SUPPRESSOR FUNCTION FOR PTPN1 IN MYELOPROLIFERATIVE NEOPLASMS

      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.
    • UNDERSTANDING THE CELLULAR AND MOLECULAR MECHANISMS OF CEREBRAL CAVERNOUS MALFORMATION 3 (CCM3)

      Howell, Brian; Mansaray-Storms, Zainab Y. (2016)
      Cerebral cavernous malformation 3 (CCM3) is one of three genes which when mutated plays a role in the neurovascular disease, cerebral cavernous malformation. Through a number of diverse binding partners, CCM3 plays a critical role in modulating several processes including cell survival, migration and vascular development. However, how CCM3 regulates many of these pathways remains unclear. An interaction with Stk25, a serine/threonine kinase with roles in cell polarity suggests CCM3 might play a role in the functions of Stk25. Here we characterize a role for CCM3 in cellular polarity. We identify a function for CCM3 in epithelial polarity through its association with and regulation of the conserved LKB1 signaling pathway. We find that CCM3 associates with STRADα, the regulatory pseudokinase of the LKB1 complex, and is necessary for LKB1-mediated cell polarization. To determine whether this novel association of CCM3 with STRADα and LKB1 pathway plays a role in CCM3-phenotype in endothelial cells, we analyzed the gene expression profiles of endothelial cells deficient in CCM3 protein. We identified changes in gene expression induced by CCM3 knockdown, particularly a significant downregulation in expression of cell adhesion molecules, a dysregulation of extracellular matrix signaling and an activation of p53 signaling pathway. This work defines a novel regulatory role for CCM3 in epithelial cell polarity and provides preliminary insights into downstream signaling pathways affected by the reduction of CCM3 in endothelial cells with potential impact in CCM disease pathogenesis.