Human Immunodeficiency Virus type I genome consists of two identical RNA molecules that are non-covalently linked to form a dimer. HIV-1 immature and mature genomic RNA (gRNA) dimers were found in protease defective (PR -) and wild type virions, respectively, and the 5'untranslated region (5' UTR) was shown to play key roles during the genome dimerization process; but the dimerization mechanism still remains to be clarified My research project is to characterize the dimerization process and the role of 5' UTR in genome dimerization in virions produced by tissue culture cells. I'll firstly show the dimer maturation processes of HIV-1 gRNA isolated from newly released to grown-up (≥10h old) wild type, PR-, and SL1 defective (DeltaIDS) virions respectively. The results showed that HIV-1 gRNA dimer maturation process was protease-dependent and involved multiple steps: from low to high dimerization level and dimer thermostability, and from low dimer mobility to intermediate and high mobility. PR- virions did not freeze gRNA conformation in the primordial nascent state and gRNA changed from monomeric in newly released virions to half dimeric in grown-up virions, which showed that genome was packaged in the form of monomeric RNA or fragile dimers, more thermolabile than immature dimers in grown-up PR- virions. DeltaDIS inhibited gRNA dimerization by about 50% in newly released virions, though grown-up DeltaDIS gRNA was fully dimeric, which indicated that the DIS played the initiation role in gRNA dimerization in HIV-1 virions. The gRNA dimerization rate in PR- or DeltaDIS virions was much slower than that in wild type virions. These results show for the first time the whole process of dimer maturation after virion release, the gRNA conformation rearrangement in PR- virions, and the initiation role of the DIS in HIV-1 virions. Next, I'll provide a rather systematic search for the contribution of different regions in 5' UTR to HIV-1 gRNA dimerization by studying selected mutations singly or together with defective SL1. The results showed that the 5'trans-activation response element (5'TAR) was directly involved in gRNA dimerization, and a long distance base-pairing interaction between a sequence in U5 region (nts105-1l5) and another around the initiation codon of the gag gene (nts334-344) was structurally contributive to gRNA dimerization. Deletions of sequences around the 3'end of Primer Binding Site (PBS) stem-loop moderately decreased gRNA dimerization level. Other sequences in 5' UTR except DIS/SL1, which was previously known to play important roles, didn't show any systematic role. Here the results suggested that the absence of inhibition on gRNA dimerization level with defective DIS might be the compensation of the direct role of 5'TAR; and wild type-like dimerization level of DeltaTAR must be the direct contribution of the DIS.

Heart failure represents an important cause of death in Western Countries. The pathophysiology of heart failure is mainly associated with abnormalities in intracellular calcium control. We previously showed that Egr-1 negatively regulates expression of sodium-calcium exchanger (NCX) in vivo and in vitro. Here we tested the hypothesis that Egr-1 regulates expression of calcium storage proteins in the sarco-endoplasmic reticulum (SER), calsequestrin (CSQ) and/or ER, calreticulin (CRT) directly or indirectly via Egr-1:NFAT (nuclear factor of activated T-cells) formation. Secondarily, we hypothesized that this will reduce calcium mobilization. We found that undifferentiated 1293F cells, overexpressing Egr-1, have reduced CSQ compared to control H9c2 cells. We demonstrated that Egr-1 negatively regulates CSQ but not CRT expression. The Egr-1 mediated decrease in CSQ is linked to decreased calcium availability. Repression is by a novel NAB-independent (NGFI-A binding protein) activity localized to a.a. region 1-307. We conclude that Egr-1-mediated reductions in calcium storage protein expression alter calcium availability for cardiac contraction/relaxation.

Paediatric human immunodeficiency virus (HIV) infection has become a major socio-economic health problem in recent years as the number of HIV-1 infected children steadily increases. The majority of these infants are infected through mother-to-child transmission, with the frequency of vertical transmission varying between 12,9% and 65%. In order to implement appropriate management and possible treatment of these infected neonates, it is essential to have reliable laboratory tests for the early diagnosis of an HIV infection. At the time that this study was initiated, the diagnosis of HIV-1 infection in the Groote Schuur Hospital Virology Laboratory depended almost exclusively on serological assays. Such assays are of limited value for infants under 18 months of age, as maternal lgG antibody to HIV-1 is transferred via the placenta and may persist in the baby for up to 18 months. Available lgG antibody tests do not distinguish reliably between passively acquired maternal antibody and that produced by the infant itself. A valuable method of establishing the presence of true infection is provided by the polymerase chain reaction (PCR) technique which allows the identification, and subsequent exponential amplification of low levels of specific viral nucleic acid using specific oligonucleotide primers. A major aim of this study was to develop and instigate a (PCR) assay for the early diagnosis of HIV infection in infected infants. This was successfully achieved by the adaptation and optimization of an existing standard PCR protocol to suit the specific needs of a routine diagnostic service. Preliminary requirements involved the selection of primers and probes and establishing optimal parameters for: ionic strength, Taq DNA polymerase concentration, primer concentration, deoxynucleotide triphosphate concentration, and hybridization conditions for most efficient functioning of the test. The devised method entailed the extraction of proviral DNA from peripheral blood mononuclear cells, amplification of HIV-1 specific sequences by PCR, and identification by Southern blot hybridization with digoxigenin (DIG)-labelled probes. Thereafter the efficacy of the assay was tested on 45 infants (under 15 months of age) all born to seropositive mothers and therefore at risk for HIV infection. Forty-two of these infants had antibodies to HIV-1 and the remaining 3 were seronegative. The latter 3 also tested negative for HIV proviral DNA when PCR was performed, using at least 2 different HIV-1 primer pairs and their respective DIG-labelled probes. However, 27 (64%) of the 42 seropositive infants were also HIV-PCR positive and the remaining 15 (36%) seropositive infants were negative for HIV proviral DNA. Positive PCR tests correlated well with clinical data indicative of active HIV-1 infection for the majority of infants in the neonatal period, although it could not provide proof of infection in newborn babies (less than 1 week of age). The development of an in-house PCR protocol specific for HIV-1 has not only provided a valuable diagnostic assay for neonatal infection, but has also given insight into the parameters required for high sensitivity and the stringent precautionary measures that need to be applied to avoid contamination problems. The second part of this study was devoted to DNA sequence analysis of cloned HIV isolates from an infected mother and her 3-month-old infant. Nucleotide sequence variation between isolates of HIV-1 has been well documented. Examination of the third variable region (particularly the V3- loop) in the env gene of HIV-1 of our mother-infant pair confirmed this variation and provided the first genetic epidemiological data of this nature in the local community. Proviral DNA from both mother and baby was amplified using V3-specific degenerate primers and cloned. Clones containing the insert DNA were 2 identified by colony-blot hybridization. Their nucleotide and amino acid sequences were analyzed by using various computer programs. The degree of similarity between variants from the mother and infant in this study differed to a large extent from previous studies. The virus population harboured by the mother displayed highly homogeneous V3 sequences (1,04% variation) compared to the isolates from her 3-month-old infant, which showed a higher degree (1,8%) of heterogeneity. Phylogenetic analysis of the different isolates from mother and infant demonstrated that an HIV-1 subtype C virus was the infectious agent. This classification was confirmed by the characteristic amino-acid sequence of the tetrapeptide motif of the V3 loop present in the isolates from both mother and infant as well as the absence of a potential N-linked glycosylation site proximal to the first cysteine of the V3 loop, which is characteristic of subtype C viruses. Based on the amino acids present at positions 306 and 320 of the V3 loop, it could also be concluded that isolates from both the mother and her baby were consistent with the non-syncytium inducing (NSI) phenotype of HIV-1, thus indicating that, contrary to popular belief, NSI variants can be responsible for initiating infection. Data obtained from these genetic investigations of variants involved in vertical transmission of HIV-1 can form a useful basis for future comparative studies.

No description available.

No description available.

Gene expression profiles obtained by means of semi-quantitative RT-PCR showed that both PPP1R1B and PPP1R3C were frequently silenced in multiple carcinomas. Bisulfite treated tumor DNA was subjected to Methylation-specific PCR (MSP) using primers flanking across the ∼130bp CpG island of the promoter of the particular gene of interest. It was revealed that PPP1R1B and PPP1R3C gene silencing in the carcinoma cell lines were due to promoter CpG island hypermethylation. Such claim was further confirmed by bisulfite genomic sequencing (BGS). Treatment with 5' azacytidine and TSA restored PPP1R1B and PPP1R3C expression in carcinoma cells through demethylating the hypermethylated promoter. In terms of cancer growth inhibition, ectopic expression of PPP1R1B and PPP1R3C could significantly inhibit the proliferation of carcinoma cell lines by 40--50% and 50--60%, respectively, according to the result of anchorage-dependent colony formation assay. / Overall, we believed that PPP1R1B and PPP1R3C are the putative tumor suppressor genes in which their expression silencing through promoter CpG island hypermethylation may be strongly linked to the development of cancer. / Protein Phosphatase 1 regulatory subunits are a family of small molecules which define the substrate specificity and subcellular localization of protein phosphatase-1 upon their interactions. Downregulation of Protein Phosphatase 1 regulatory subunits were often associated with tumor initiation and progression, for example, ASPP family (PPP1R13A and PPP1R13B). In the present study, PPP1R1B and PPP1R3C were identified in which their tumor suppressor functions had been investigated. / Reduction in the level of p-ser473 Akt and p-ser552 beta-catenin could be observed when PPP1R1B expression was restored in respective carcinoma cells. In addition, the transcription activity of AP-1 decreased in the presence of full-length PPP1R1B expression as determined by Dual-Luciferase reporter assay system. Ectopic expression of PPP1R3C increased the amount of inactive pSer9-GSK-3beta as shown in the western blot analysis and a concomitant increased in p53 level was observed in colorectal carcinoma HCT116 cells. Transcription activity of NF-kappaB in HCT116 cells was increased but decreased in KYSE150 cells (ESCC) in the presence of PPP1R3C expression. Subcellular localization study using the GFP-fusion protein revealed that PPP1R1B protein was distributed throughout the cytoplasm while PPP1R3C protein was mainly localized around the nuclear membrane. / Leung, Ching Hei. / Adviser: Tak Cheung Chan. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 160-183). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Poon Cho Sun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 83-91). / Abstract also in Chinese. / ACKNOWLEDGEMENT --- p.v / ABSTRACT --- p.vi / LIST OF ABBREVIATIONS --- p.x / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Literature review --- p.5 / Chapter 2.1 --- Epidemiology and aetiology of cervical cancer --- p.5 / Chapter 2.1.1 --- Incidence and mortality --- p.5 / Chapter 2.1.2 --- Aetiology --- p.6 / Chapter 2.1.2.1 --- Oral contraceptive pills and cervical cancer --- p.7 / Chapter 2.1.2.2 --- Human papilloma virus (HPV) and cervical cancer --- p.7 / Chapter 2.1.2.3 --- Immunity and cervical cancer --- p.8 / Chapter 2.1.2.4 --- Socio-economic differences and cervical cancer --- p.9 / Chapter 2.1.2.5 --- Smoking and cervical cancer --- p.9 / Chapter 2.1.2.6 --- Male role and cervical cancer --- p.9 / Chapter 2.1.2.7 --- Nutrition and cervical cancer --- p.10 / Chapter 2.2 --- Oncogenes and tumour suppressor genes --- p.10 / Chapter 2.2.1 --- Oncogene --- p.10 / Chapter 2.2.2 --- Tumour suppressor gene --- p.13 / Chapter 2.2.3 --- Alterations of oncogene in cervical cancer --- p.16 / Chapter 2.2.4 --- Alterations of tumour suppressor genes in cervical cancer --- p.18 / Chapter 2.3 --- Alterations of chromosome 1 in cervical cancer --- p.19 / Chapter 2.3.1 --- Cytogenetic tudy --- p.19 / Chapter 2.3.2 --- Molecular genetic study --- p.21 / Chapter 2.4 --- Loss of heterozygosity (LOH) --- p.21 / Chapter Chapter 3 --- Materials and methods --- p.24 / Chapter 3.1 --- Materials --- p.24 / Chapter 3.1.1 --- Patients --- p.24 / Chapter 3.1.2 --- Specimens --- p.24 / Chapter 3.1.2.1 --- Blood samples --- p.24 / Chapter 3.1.2.2 --- Tumour tissue specimens --- p.24 / Chapter 3.1.3 --- Chemicals and reagents --- p.25 / Chapter 3.1.3.1 --- Chemicals --- p.25 / Chapter 3.1.3.2 --- Reagents --- p.27 / Chapter 3.1.3.3 --- Markers --- p.29 / Chapter 3.1.4 --- Major equipment --- p.33 / Chapter 3.2 --- Methodology --- p.33 / Chapter 3.2.1 --- DNA extraction --- p.33 / Chapter 3.2.2 --- DNA amplification --- p.35 / Chapter 3.2.2.1 --- Validation of PCR primers and optimisation of PCR condition --- p.35 / Chapter 3.2.2.2 --- End labelling of the primer by (γ-32p)ATP --- p.35 / Chapter 3.2.2.3 --- PCR for LOH detection --- p.36 / Chapter 3.2.2.4 --- Electrophoresis --- p.37 / Chapter 3.2.2.5 --- Gel dry and radioautography --- p.38 / Chapter 3.2.2.6 --- PCR analysis of the D1S80 and D1S76 loci --- p.39 / Chapter 3.3 --- Determination of Loss of heterozygosity (LOH) --- p.39 / Chapter 3.4 --- Statistical analysis --- p.40 / Chapter Chapter 4 --- Results --- p.41 / Chapter 4.1 --- LOH analysis in cervical cancer --- p.41 / Chapter 4.2 --- LOH and age in cervical cancer --- p.60 / Chapter 4.3 --- LOH and pathological grade in cervical cancer --- p.62 / Chapter 4.4 --- LOH and clinical stage in cervical cancer --- p.64 / Chapter 4.5 --- LOH and clinical status in cervical cancer --- p.66 / Chapter Chapter 5 --- Discussion --- p.68 / Chapter 5.1 --- Microsatellite markers --- p.69 / Chapter 5.2 --- PCR condition --- p.70 / Chapter 5.3 --- LOH in cervical cancer --- p.72 / Chapter 5.4 --- Correlation of LOH with clinico-pathologic characteristics of cervical cancer --- p.76 / Chapter 5.4.1 --- LOH and age --- p.78 / Chapter 5.4.2 --- LOH and clinical stage --- p.78 / Chapter 5.4.3 --- LOH and pathologic grade --- p.79 / Chapter 5.4.4 --- LOH and clinical status --- p.79 / Chapter Chapter 6 --- Conclusion --- p.80 / Chapter Chapter 7 --- References --- p.83

Os craniofaringiomas são os tumores mais frequentes da região hipotálamohipofisária na faixa etária pediátrica. Apesar de serem histologicamente benignos, sua tendência infiltrativa e seu comportamento agressivo resultam em significante morbimortalidade. Histologicamente podem ser divididos em dois subtipos: adamantinomatosos e papilíferos. A patogênese dos craniofaringiomas é pouco compreendida. Mutações no gene CTNNB1, que codifica a proteína beta-catenina, são a única alteração molecular conhecida até o momento implicada na tumorigênese dos craniofaringiomas adamantinomatosos. Tais mutações afetam o sítio de degradação da beta-catenina, que passa a se acumular no citoplasma e no núcleo, ativando excessivamente a via de sinalização WNT, através da ligação aos fatores de transcrição da família LEF/TCF, levando a tumorigênese. Recentemente foi descoberto um novo mecanismo de determinação da linhagem celular hipofisária regulado pela beta-catenina, através do qual ela interage diretamente com o PROP1 para determinar a diferenciação celular hipofisária. De acordo com esse modelo, o complexo protéico PROP1/beta- catenina atua simultaneamente como repressor do HESX1 e ativador do PIT1, dependendo dos co-fatores associados. Pacientes com mutações germinativas inativadoras no PROP1 desenvolvem hipopituitarismo e podem apresentar aumento hipofisário com imagens de ressonância nuclear magnética (RNM) da região selar muitas vezes semelhantes àquelas dos craniofaringiomas, com hiperssinal em T1. Por outro lado, camundongos com expressão persistente do Prop1 exibem defeitos na regulação da proliferação celular hipofisária, incluindo cistos da bolsa de Rathke, hiperplasia adenomatosa e tumores, sugerindo que mutações com ganho de função no PROP1 também poderiam contribuir para a patogênese de tumores hipofisários em seres humanos. A semelhança entre as imagens de RNM dos pacientes com craniofaringiomas e daqueles com aumento hipofisário devido a mutações inativadoras no PROP1, e o fato de que camundongos transgênicos com expressão persistente do Prop1 apresentam aumento da susceptibilidade a tumores hipofisários, deram base a nossa hipótese de que uma desregulação na expressão do PROP1 em humanos poderia estar envolvida na patogênese dos craniofaringiomas adamantinomatosos. Esse trabalho teve como objetivo avaliar a presença de mutação somática no exon 3 do CTNNB1 e avaliar a expressão desse gene e do gene PROP1 em craniofaringiomas adamantinomatosos. Foram obtidas 14 amostras desse tipo de tumor por meio da ressecção terapêutica. As amostras foram submetidas à extração do RNA e posterior transcrição reversa para obtenção de cDNA. A partir do cDNA foi realizada PCR e sequenciamento do exon 3 do CTNNB1 em todas as amostras. Porém, a avaliação por PCR em tempo real foi realizada apenas em 12 amostras, devido à qualidade inadequada de 2 amostras para submissão a essa metodologia. Foram encontradas mutações missense, em heterozigose em 9 das 14 amostras, sendo 5 previamente descritas e 2 ainda não descritas em craniofaringiomas adamantinomatosos. Hiperexpressão do CTNNB1 foi encontrada em 7 amostras, sendo 5 com mutação e 2 sem mutação no CTNNB1.A hiperexpressão variou de 2,5 a 6,2 vezes maior que o pool de hipófise normal. Contudo, a expressão do PROP1 foi indetectável em todas as amostras. Concluímos que o aumento da expressão do CTNNB1 presente em 58% das amostras sugere o envolvimento também da hiperexpressão desse gene na etiopatogenia do craniofaringioma adamantinomatoso, enquanto a ausência de expressão do PROP1 afasta a participação desse gene na etiopatogenia do craniofaringioma adamantinomatoso / Craniopharyngiomas are the the commonest tumors to involve the hypothalamo-pituitary regions in childhood population. Histologically they are benign, and can be divided in two primary subtypes: the adamantinomatous and the papillary. Although histologically benign, their infiltrative tendency and aggressive behavior can result in great morbidity. The pathogenesis of craniopharyngiomas is poorly understood. To date, beta-catenin gene (CTNNB1) mutations have been identified only in the adamantinomatous subtype. These mutations affect the degradation target box of beta-catenin that accumulates in the cytoplasm and the nucleus increasing the transcriptional activity of WNT pathway through interaction with the transcription factors of LEF/TCF family, leading to tumorigenesis. Recently, an interaction between beta-catenin and PROP1 was described as a new mecanism for beta-catenindependent regulation of pituitary cell-lineage determination. According to this novel model, the PROP1/beta-catenin proteic complex would act as a binary switch to simultaneously repress the transcription factor HESX1 and to activate expression of transcription factor PIT1, depending on the associated cofactors. Patients with loss-of-function mutations in PROP1 present combined pituitary hormonal deficiency generally associated with pituitary enlargement and the magnetic resonance imaging (MRI) of the sellar region in these patients sometimes resembles that of the craniopharyngiomas, with T1 hyperintense signal. On the other hand, transgenic mice with persistent Prop1 expression exhibit defects consistent with misregulation of pituitary cell proliferation, including adenomatous hyperplasia with formation of Rathke\'s cleft cysts and tumors suggesting that misregulation of PROP1 expression in human could contribute to pathogenesis of pituitary tumors. The similarity between the MRI images of craniopharyngiomas patients and that of patients with loss-of-function mutations in PROP1, associated with the fact that transgenic mice with persistent Prop1 expression exhibit increased susceptibility to pituitary tumors gave rise to our hypothesis that a misregulation of PROP1 expression could be involved in the pathogenesis of adamantinomatous craniopharyngiomas. The aim of this study was to analyze the presence of somatic mutations in exon 3 of CTNNB1 and the expression pattern of this gene and the PROP1 gene in adamantinomatous craniopharyngiomas. Fourteen samples were obtained from therapeutic surgery and submitted to RNA extraction and reverse transcription in order to produce the cDNA. The cDNA was used as a template to CTNNB1 exon 3 PCR reaction followed by direct sequencing of all samples. However, the real-time RT-PCR analysis was realized only in 12 samples, since 2 of them had an insufficient quality for this method. Missence, heterozygous mutations were found in 9 out of 14 samples; five were previously described and 2 not yet described in adamantinomatous craniopharyngiomas. Overexpression of CTNNB1 was found in 7 samples, which them 5 with CTNNB1 mutation 2 whitout. The overexpression ranged from 2.5 to 6.2 fold more than pituitary normal pool. However, the PROP1 expression was undetectable in all the samples. We could conclude that the amount of 58% CTNNB1 overexpressed samples suggest also a role of this overexpression in the pathogenesis of adamantinomatous craniopharingiomas, while the undetectable levels of PROP1 exclude a role of this gene in the pathogenesis of adamantinomatous craniopharingiomas

Os craniofaringiomas são os tumores mais frequentes da região hipotálamohipofisária na faixa etária pediátrica. Apesar de serem histologicamente benignos, sua tendência infiltrativa e seu comportamento agressivo resultam em significante morbimortalidade. Histologicamente podem ser divididos em dois subtipos: adamantinomatosos e papilíferos. A patogênese dos craniofaringiomas é pouco compreendida. Mutações no gene CTNNB1, que codifica a proteína beta-catenina, são a única alteração molecular conhecida até o momento implicada na tumorigênese dos craniofaringiomas adamantinomatosos. Tais mutações afetam o sítio de degradação da beta-catenina, que passa a se acumular no citoplasma e no núcleo, ativando excessivamente a via de sinalização WNT, através da ligação aos fatores de transcrição da família LEF/TCF, levando a tumorigênese. Recentemente foi descoberto um novo mecanismo de determinação da linhagem celular hipofisária regulado pela beta-catenina, através do qual ela interage diretamente com o PROP1 para determinar a diferenciação celular hipofisária. De acordo com esse modelo, o complexo protéico PROP1/beta- catenina atua simultaneamente como repressor do HESX1 e ativador do PIT1, dependendo dos co-fatores associados. Pacientes com mutações germinativas inativadoras no PROP1 desenvolvem hipopituitarismo e podem apresentar aumento hipofisário com imagens de ressonância nuclear magnética (RNM) da região selar muitas vezes semelhantes àquelas dos craniofaringiomas, com hiperssinal em T1. Por outro lado, camundongos com expressão persistente do Prop1 exibem defeitos na regulação da proliferação celular hipofisária, incluindo cistos da bolsa de Rathke, hiperplasia adenomatosa e tumores, sugerindo que mutações com ganho de função no PROP1 também poderiam contribuir para a patogênese de tumores hipofisários em seres humanos. A semelhança entre as imagens de RNM dos pacientes com craniofaringiomas e daqueles com aumento hipofisário devido a mutações inativadoras no PROP1, e o fato de que camundongos transgênicos com expressão persistente do Prop1 apresentam aumento da susceptibilidade a tumores hipofisários, deram base a nossa hipótese de que uma desregulação na expressão do PROP1 em humanos poderia estar envolvida na patogênese dos craniofaringiomas adamantinomatosos. Esse trabalho teve como objetivo avaliar a presença de mutação somática no exon 3 do CTNNB1 e avaliar a expressão desse gene e do gene PROP1 em craniofaringiomas adamantinomatosos. Foram obtidas 14 amostras desse tipo de tumor por meio da ressecção terapêutica. As amostras foram submetidas à extração do RNA e posterior transcrição reversa para obtenção de cDNA. A partir do cDNA foi realizada PCR e sequenciamento do exon 3 do CTNNB1 em todas as amostras. Porém, a avaliação por PCR em tempo real foi realizada apenas em 12 amostras, devido à qualidade inadequada de 2 amostras para submissão a essa metodologia. Foram encontradas mutações missense, em heterozigose em 9 das 14 amostras, sendo 5 previamente descritas e 2 ainda não descritas em craniofaringiomas adamantinomatosos. Hiperexpressão do CTNNB1 foi encontrada em 7 amostras, sendo 5 com mutação e 2 sem mutação no CTNNB1.A hiperexpressão variou de 2,5 a 6,2 vezes maior que o pool de hipófise normal. Contudo, a expressão do PROP1 foi indetectável em todas as amostras. Concluímos que o aumento da expressão do CTNNB1 presente em 58% das amostras sugere o envolvimento também da hiperexpressão desse gene na etiopatogenia do craniofaringioma adamantinomatoso, enquanto a ausência de expressão do PROP1 afasta a participação desse gene na etiopatogenia do craniofaringioma adamantinomatoso / Craniopharyngiomas are the the commonest tumors to involve the hypothalamo-pituitary regions in childhood population. Histologically they are benign, and can be divided in two primary subtypes: the adamantinomatous and the papillary. Although histologically benign, their infiltrative tendency and aggressive behavior can result in great morbidity. The pathogenesis of craniopharyngiomas is poorly understood. To date, beta-catenin gene (CTNNB1) mutations have been identified only in the adamantinomatous subtype. These mutations affect the degradation target box of beta-catenin that accumulates in the cytoplasm and the nucleus increasing the transcriptional activity of WNT pathway through interaction with the transcription factors of LEF/TCF family, leading to tumorigenesis. Recently, an interaction between beta-catenin and PROP1 was described as a new mecanism for beta-catenindependent regulation of pituitary cell-lineage determination. According to this novel model, the PROP1/beta-catenin proteic complex would act as a binary switch to simultaneously repress the transcription factor HESX1 and to activate expression of transcription factor PIT1, depending on the associated cofactors. Patients with loss-of-function mutations in PROP1 present combined pituitary hormonal deficiency generally associated with pituitary enlargement and the magnetic resonance imaging (MRI) of the sellar region in these patients sometimes resembles that of the craniopharyngiomas, with T1 hyperintense signal. On the other hand, transgenic mice with persistent Prop1 expression exhibit defects consistent with misregulation of pituitary cell proliferation, including adenomatous hyperplasia with formation of Rathke\'s cleft cysts and tumors suggesting that misregulation of PROP1 expression in human could contribute to pathogenesis of pituitary tumors. The similarity between the MRI images of craniopharyngiomas patients and that of patients with loss-of-function mutations in PROP1, associated with the fact that transgenic mice with persistent Prop1 expression exhibit increased susceptibility to pituitary tumors gave rise to our hypothesis that a misregulation of PROP1 expression could be involved in the pathogenesis of adamantinomatous craniopharyngiomas. The aim of this study was to analyze the presence of somatic mutations in exon 3 of CTNNB1 and the expression pattern of this gene and the PROP1 gene in adamantinomatous craniopharyngiomas. Fourteen samples were obtained from therapeutic surgery and submitted to RNA extraction and reverse transcription in order to produce the cDNA. The cDNA was used as a template to CTNNB1 exon 3 PCR reaction followed by direct sequencing of all samples. However, the real-time RT-PCR analysis was realized only in 12 samples, since 2 of them had an insufficient quality for this method. Missence, heterozygous mutations were found in 9 out of 14 samples; five were previously described and 2 not yet described in adamantinomatous craniopharyngiomas. Overexpression of CTNNB1 was found in 7 samples, which them 5 with CTNNB1 mutation 2 whitout. The overexpression ranged from 2.5 to 6.2 fold more than pituitary normal pool. However, the PROP1 expression was undetectable in all the samples. We could conclude that the amount of 58% CTNNB1 overexpressed samples suggest also a role of this overexpression in the pathogenesis of adamantinomatous craniopharingiomas, while the undetectable levels of PROP1 exclude a role of this gene in the pathogenesis of adamantinomatous craniopharingiomas

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease, with poor prognosis and no cure. Substantial evidence implicates inflammation and associated oxidative stress as a potential mechanism for ALS, especially in patients carrying the SOD1 mutation and, therefore, lacking anti-oxidant defense. The brain is particularly vulnerable to oxidation due to the abundance of polyunsaturated fatty acids, such as docosahexaenoic acid (DHA), which can give rise to several oxidized metabolites. Accumulation of a DHA peroxidation product, CarboxyEthylPyrrole (CEP) is dependent on activated inflammatory cells and myeloperoxidase (MPO), and thus marks areas of inflammation-associated oxidative stress. At the same time, generation of an alternative inactive DHA peroxidation product, ethylpyrrole, does not require cell activation and MPO activity. While absent in normal brain tissues, CEP is accumulated in the central nervous system (CNS) of ALS patients, reaching particularly high levels in individuals carrying a SOD1 mutation. ALS brains are characterized by high levels of MPO and lowered anti-oxidant activity (due to the SOD1 mutation), thereby aiding CEP generation and accumulation. Due to DHA oxidation within the membranes, CEP marks cells with the highest oxidative damage. In all ALS cases CEP is present in nearly all astrocytes and microglia, however, only in individuals carrying a SOD1 mutation CEP marks >90% of neurons, thereby emphasizing an importance of CEP accumulation as a potential hallmark of oxidative damage in neurodegenerative diseases.