Indiana University-Purdue University Indianapolis (IUPUI) / Neurofibromatosis type 2 (NF2) is an autosomal dominant cancer predisposition in which loss of heterozygosity at the NF2 gene locus leads to the development of tumors of neural crest derived origin, most commonly bilateral vestibular schwannomas. There are currently no FDA approved chemotherapeutic agents for treatment in patients with NF2. Development of therapeutic agents has been hampered by our incomplete knowledge of how Merlin, the protein product of the NF2 gene, functions as a tumor suppressor. In order develop a deeper understanding for how loss of Merlin leads to oncogenic transformation in Schwann cells we have developed a genetically engineered mouse model (GEMM) of Neurofibromatosis Type 2 in which functional expression of Merlin is lost in Schwann cell precursors. In parallel studies utilizing these mice, we have sought to understand the pathophysiology driving tumor formation in Merlin deficient Schwann cells. In Chapter 1, we explore the role of Merlin as a negative regulator of the Group A p21 activated kinases, PAK1 and PAK2. We demonstrate that PAK1, a previously well established oncogene in solid tumors and Merlin binding partner, is hyperactivated in Merlin deficient schwannomas. Through therapeutic interventions and genetic manipulations we demonstrate that inhibition of PAK1 was capable of reducing tumor formation and alleviating sensorineural hearing loss in our NF2 GEMM. In Chapter 2, we investigate the role of NF-kB inducing kinase (NIK) and NF-kB signaling in the formation and growth of Merlin deficient Schwann cell tumors. Prior work in our lab as well as by others demonstrated elevated NF-kB signaling in Merlin deficient Schwann cell tumors. We observed accumulation of a catalytically active fragment of NF-kB inducing kinase and present data that accumulation of a 55Kd constitutively active fragment of NIK is sufficient trigger wild type Schwann cells to form tumors. In vivo however, Schwann cell intrinsic expression of NIK is not required for tumor formation or growth. / 2 years (2021-05-24)

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Indiana University-Purdue University Indianapolis (IUPUI) / Communication is a vital tool used by humans to share information, coordinate behavior, and survive. However, the ability to communicate can become disrupted or remain absent in individuals with neurodevelopmental disorders: two prominent examples include autism spectrum disorders and developmental language disorders, found in nearly 2% and 10% of the population, respectively. Communication disorders are devastating to the autonomy and quality of life of affected individuals, but clinical solutions are limited due to the complex and often unknown neural etiology underlying these conditions. One known disorder with high incidence of disrupted communication is Neurofibromatosis type 1, the genetic disease caused by heterozygosity of the Ras GTPase-activating protein-coding gene NF1. Mice heterozygous for their ortholog of this gene (Nf1+/-) have been shown to recapitulate neuropsychiatric conditions seen in patients. Using a courtship trial paradigm as a model for testing communication, I have demonstrated that Nf1+/- male mice showed deficits in both courtship and non-courtship social behavior as well as a decrease in the number and duration of ultrasonic vocalizations (USVs). Immediate early gene (IEG) immunohistochemistry (IHC) in neurons of courtship-relevant brain regions revealed the Shell of the Nucleus Accumbens (NAcS) as a dysfunctional brain region in Nf1+/- mice compared to WT male mice following courtship trial. Optogenetic targeting of the Nucleus Accumbens (NAc) restored courtship social behaviors and USV number, but not USV duration or non-courtship gestural social behaviors, in Nf1+/- males. This study contributes to a preclinical foundation for understanding etiology of communication disorders in patients.

Neurofibromatosis Type II (NF2) is a neurological disorder arising from mutations in the rif2 gene. NF2 is characterized by formation of bilateral vestibular schwannomas. These tumors arise from Schwann cells, the myelin-forming glia in nerves. Schwannoma cells lose the characteristic bipolar, spindle morphology and assume a round fibroblast-like phenotype. Phenotypic de-differentiation of schwannomas has been attributed to increased levels of Cdc42/Rac-GTP and activation of downstream pathways. The n/2 gene encodes the tumor suppressor called merlin. It is targeted to the plasma membrane by direct binding to paxillin at paxillin-binding domain 1, encoded by exon 2 of the nj2 gene. At the plasma membrane, merlin associates with B1-integrin and erbB2/3 receptors and actin regulating proteins. We hypothesize that merlin modulates actin polymerization, and thus cell shape, by controlling the activity of actin filament regulating proteins. We developed an in vitro model ofNF2 using ad-ere ( ad-Cre) viral mediated deletion of nj2 exon 2 in primary mouse Schwann cells. Within 5 days of ad-Cre infection, merlin levels fall to 40% of normal levels in Schwann cells. Moreover, the expressed merlin protein has the expected lower molecular weight and does not target to the plasma membrane. Schwann cells expressing this mutant merlin lose their characteristic bipolar shape. We tested the activation levels of2 candidate Cdc42/Rac dependent-actin regulating proteins in these cells. Using immunofluorescence, we found that the activity of these proteins increased dramatically within 4 days of n/2 inactivation. This increase in activity was then confirmed with western blotting. We conclude that the function of these actin-filament regulating proteins could contribute to changes in morphology associated with schwannoma formation in NF2.

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Made available in DSpace on 2016-01-26T12:51:35Z (GMT). No. of bitstreams: 1 helenicebianchibolini_tese.pdf: 2235516 bytes, checksum: 0e1ddb1957f1b10e0d67a793c7e4a245 (MD5) Previous issue date: 2010-10-27 / The practical problem observed referred to the clinical symptoms of NF1, involving intellectual performance and psychosocial characteristics of their carriers. This sends us to the NF1-intelligence interface. Objective: To identify and compare indices of intelligence and their frequencies in patients with NF1, attended at CEPAN. Methods and Casuistry: Medical records were used in research, semi-structured interview, the Wechsler Scales and Test Progressive Matrices Scale-General. Were applied indidually, to the 77 subjects, of which 30 patients with NF1, 17 family members, and 30 non- carriers between 2006 and 2010. The data were treated qualitative-quantitative. Results: The socioeconomic and cultural rights did not differ between subjects. Minors (<20 ) and larger (>20 ) time spent in the execution of Test Progressive Matrices Sacale-General were relatives of patients with NF1 and most were using medication. Mean correct responses were lower in patients with NF1, they had one and two symptoms that bothered when they were diagnosed, currently, the troubled portability three, four and two symptoms. Patients with NF1 had their first symptoms identified with more than five years age, they had relatives suffering from NF1 1st and/or 2nd degrees of relatedness (vertical transmission). They had mild MR and moderate, and learning disabilities. The subjects of this investigation showed TIQ; VIQ; TIQ/Gc; IOP/Gv; IVP/Gt average and below average; although the ability Reasoning/ Fluid Intelligence Gf category V. Conclusions: The subjects of this investigation have average and average lower, with limited sustainability. There are differences in intellectual performance among them: relatives of patients with NF1 are superior to the carriers and no- carriers are superior to both. There are mental retardation, learning disabilities, difficulties visual-perceptual-motor, memory impairments, and speech in written and spoken language in patients with NF1. There are no correlations between TIQ/Gc; IMO/Gsm; ICV/Gc; IOP/Gv; IVP/Gt and number of symptoms. There is no correlation between IQ, intellectual level, types, numbers, uncomfortable symptoms and age of onset of symptoms. / O problema prático observado, referiu-se aos sintomas clínicos de NF1, que envolviam o desempenho intelectual e as características psicossociais de seu portador, remetendo-nos à interface inteligência Neurofibromatose 1-NF1. Objetivo: Identificar e comparar os índices de inteligência e suas frequências em portadores de NF 1 atendidos no CEPAN. Casuística e Métodos: Utilizou-se pesquisa em prontuários; entrevista semi-estruturada; as Escalas de Wechsler e Testes de Matrizes Progressivas - Escala Geral, aplicados individualmente a 77 sujeitos, dos quais 30 portadores de NF1, 17 seus familiares e 30 não-portadores, entre 2006 e 2010. Os dados receberam tratamento quali-quantitativo. Resultados: As características socioeconômicas e culturais não diferiram entre os sujeitos Os tempos menores (<20 ) e maiores (>20 ) gastos na execução do Raven - Escala Geral foram de familiares e portadores de NF1, que mais faziam uso de medicação. As médias de acertos de portadores de NF1 foram as menores; possuíam 1 e 2 sintomas que os incomodavam quando foram diagnosticados; atualmente, era a portabilidade de 3, 4 e 2 sintomas que os incomodavam; primeiros sintomas identificados com mais de 5 anos; possuíam parentes portadores de NF1 de 1º e/ou 2º graus de parentesco (transmissão vertical); apresentaram RM leve e moderada; e distúrbio de aprendizagem (QI>70) em portadores de NF1. Os sujeitos dessa investigação apresentaram quocientes de inteligência e índices fatoriais médios e médio-inferiores; a capacidade Raciocínio/ Inteligência Fluida Gf encontrou-se comprometida-categoria V. Conclusões: Os sujeitos da investigação possuem inteligência média e média inferior, porém com dificuldade de sustentabilidade. Há diferenças de desempenho intelectual: familiares de portadores de NF1 são superiores aos portadores de NF1; e não portadores são superiores a ambos. Há retardo mental, distúrbio de aprendizagem, disfunção no desenvolvimento da linguagem dificuldades viso-motoras e perceptuais, deficiências de memória e de expressão na linguagem escrita e verbal em portadores de NF1; ausência de correlação entre QIT/Gc; IMO/Gsm; ICV/Gc; IOP/ Gv; IVP/ Gt e número de sintomas; e ausência de relação entre QI; nível intelectual; tipos; números; incômodos de sintomas e faixa etária do aparecimento dos primeiros sintomas.

<p>Microarray-based comparative genomic hybridization (array-CGH) has emerged as a versatile platform with a wide range of applications in molecular genetics. This thesis focuses on the development of array-CGH with a specific aim to approach disease-related questions through improved strategies in array construction and enhanced resolution of analysis. In <b>paper I</b>, we applied an array covering 11 Mb of 22q, encompassing the <i>NF2</i> locus, for deletion detection in sporadic schwannoma. Hemizygous deletions and tumor heterogeneity were identified. Array-CGH was established as a reliable platform for detection of DNA dosage alterations. <b>Paper II</b> described the construction of the<i> NF2</i> gene-specific microarray for high-resolution scanning of deletions in the <i>NF2</i> locus. We report a novel PCR-based non-redundant strategy for microarray fabrication, which considerably improved the sensitivity and reliability of deletion detection. <b>Paper III</b> reported the first tiling-path array comprehensively covering a human chromosome. The usefulness of the 22q-array was demonstrated by applying it to detect DNA dosage-alterations in 22q-associated disorders. In <b>paper IV</b>, we optimized array-CGH protocols for deletion detection in 22q11 deletion-syndrome. We showed that genomic and cDNA clones are not optimal for analysis of 22q11 locus and that PCR-based non-redundant strategy is reliable for deletion detection in such regions. In <b>paper V</b>, we utilized the 22q-array for understanding the genetic basis of schwannomatosis. Two commonly deleted regions were identified within the <i>IGL</i> and the <i>GSTT1/CABIN1</i> loci. Further investigations using high-resolution arrays, bioinformatic analysis and mutational screening were performed. Missense mutations, specific to the schwannomatosis- and NF2 samples, were identified in the <i>CABIN1 </i>gene. <b>Paper VI</b> described the first array-CGH study for comprehensive and high-resolution profiling of deletions spanning the 17q11 locus. Both typical and atypical deletions were identified in NF1 samples. Bioinformatic analysis revealed novel segmental duplications, which can potentially mediate 17q11 deletions.</p>