O acometimento do câncer na infância é relativamente raro, com taxas relevantes de incidência de alguns tumores, como a leucemia linfoblástica aguda (LLA) e o tumor de Wilms (TW). Embora o câncer seja uma das dez primeiras causas de óbito de crianças e adolescentes e a primeira por doença a partir dos cinco anos, nas últimas décadas o progresso da terapêutica tem possibilitado um declínio nas taxas de mortalidade e expansão dos prazos de sobrevida. Desta forma, o acompanhamento efetivo no enfrentamento da doença passou a buscar análises mais amplas dos efeitos orgânicos tardios da doença e da terapêutica, incluindo as condições psicossociais do sobrevivente, como nas avaliações da qualidade de vida relacionada à saúde (QVRS). No sentido de ampliar o conhecimento e alternativas para o acompanhamento ambulatorial e periódico da condição de sobrevivência, este estudo buscou comparar o impacto na QVRS do sobrevivente adulto, dada a diferença na terapêutica de escolha para a remissão da LLA (quimioterapia) e do TW (cirurgia e quimioterapia), utilizando uma avaliação a distância da QVRS (SF-36, via telefone).Objetivos: Analisar e comparar a QVRS de sobreviventes adultos de LLA e TW, entre si e em relação a participantes sadios, acompanhados no Ambulatório Fora de Terapia do ITACI-HC-FMUSP, através da aplicação alternativa (via telefone) do SF-36.Casuística e Método: 90 participantes, acima de 18 anos. Grupo controle(CTRL) (30 sujeitos, fisicamente saudáveis, com ausência de diagnóstico prévio de câncer, recém-ingressos em curso superior) e Grupos experimentais (60 sobreviventes - Ambulatório Fora de Terapia - ITACI - HCFMUSP): grupo LLA (GLLA) - 30 sobreviventes LLA e grupo TW (GTW) 30 sobreviventes TW. A avaliação foi realizada através da aplicação, via telefone, do SF- 36. Após compilação dos domínios do SF-36, os resultados foram analisados através do teste de qui-quadrado, teste t-independente e teste de ANOVA. Resultados: Os participantes não apresentaram diferença significativa quanto a idade, a maioria eram solteiros, sem filhos e provenientes de São Paulo. O nível mais elevado de escolaridade do CTRL decorreu do critério de inclusão, mas com relevante proporção de sobreviventes no nível superior. Nos sobreviventes não houve diferença significativa de idade de diagnóstico e tempo de fora de terapia. Quanto a QVRS, houve melhores resultados dos sobreviventes masculinos em relação às sobreviventes e participantes CTRL. Especificamente, GLLA e GTW para Vitalidade e GLLA para Aspectos sociais, Saúde mental e Aspectos emocionais, no último aspecto detectada diferença também para as sobreviventes GTW. Nos sobreviventes com diagnóstico tardio (acima 53 meses) o GLLA apresentou melhores resultados na Capacidade funcional. Na percepção da própria saúde, houve diferença para todos os domínios, exceto nos Aspectos sociais e emocionais, estando as diferenças circunscritas a percepções positivas (boa, muito boa e excelente) da própria saúde pelos sobreviventes e controles. Conclusão: Particularmente no período do estudo, para a amostra selecionada e os aspectos analisados pelo SF-36 pode-se inferir que, apesar de algumas diferenças encontradas, os sobreviventes não apresentaram evidências de comprometimento de QVRS. O SF-36 (via telefone) pode ser um recurso de acesso e avaliação de QVRS de sobreviventes sob acompanhamento ambulatorial / The involvement of childhood cancer is relatively rare, with relevant incidence rates of some cancers such as Acute Lymphoblastic Leukemia (ALL) and Wilms Tumor (WT). Although cancer is one of the top ten causes of death in children and adolescents and the first disease from the age of five, in recent decades the therapeutic progress has made possible a decline in mortality rates and expansion of the survival periods. In this way, the effective monitoring in the confrontation of the disease passed to seek broader analyses of later organic effects from disease and therapy, including the psychosocial conditions of survivor, as in evaluations of healthrelated quality of life (HRQoL). In order to increase knowledge and alternatives for monitoring outpatient and periodic survival condition, this study sought to compare the impact on HRQoL of adult survivor, given the difference in the choice therapy for the remission of ALL (chemotherapy) and WT (surgery) using a remote assessment of HRQoL (SF -36 via telephone call). Objectives: Analyze and compare the HRQoL of adult survivors of ALL and WT between themselves and in relation to healthy participants, followed at the Ambulatory outside ITACI - HC - USP therapy , by alternative application ( by phone calls) of the SF - 36 . Methods: 90 participants , above 18 years. Control group (CTRL): (30 subjects, physically healthy, no history of oncological diagnosis, newly joined in higher education) and experimental groups (60 survivors - Outpatient Therapy - ITACI - HCFMUSP ): ALL group ( GALL ) - 30 ALL survivors and WT group ( GWT ) 30 WT survivors. The evaluation was performed by applying SF-36, via telephone calls. After compilation of the SF -36 domains, the results were analyzed through chi - square test, independent t test and ANOVA test. Results: Participants showed no significant difference regarding age, most were single, childless and from Sao Paulo. CTRL highest level of schooling resulted from inclusion criterion but with relevant proportion of survivors at the top level. In survivors there was no significant difference in age of diagnosis and time outside therapy. As for HRQoL there have been better results of male survivors in relation to female survivors and CTRL participants. Specifically GALL and GWT for vitality domain and GALL for social aspects, mental health and emotional aspects. In the last domain, it was detected also difference female survivors GWT. In survivors with late diagnosis (above 53 months) the GALL presented better results in functional capacity. In the perception of their own health, there were differences for all domains except in social and emotional aspects, with differences confined to positive perceptions (good, very good and excellent ) of own health by survivors and controls. Conclusion: Particularly during the study period, for the selected sample and the analyzed aspects by SF -36 can be inferred that, despite some differences, survivors did not show evidence of impairment of HRQoL . The SF -36 (via telephone calls) can be a resource of access HRQoL evaluation of survivors under ambulatory followup

A Leucemia Linfocítica Aguda na infância e adolescência é uma neoplasia de precursores linfóides de natureza heterogênea. Foi a primeira neoplasia disseminada a tornar-se curável pela quimioterapia. No Brasil os estudos cooperativos para o seu tratamento foram iniciados em 1980 com a criação do primeiro protocolo para o tratamento desta leucemia, denominado Grupo Brasileiro para o Tratamento da Leucemia na Infância. Na seqüência destes estudos foram observadas Sobrevidas Livre de Eventos de 50%, 58% e 70% nos protocolos 80, 82 e 85 respectivamente. Durante as décadas de 1980 e 1990, com a divulgação dos excelentes resultados alcançados com os regimes dos protocolos do grupo Berlin Frankfurt Münster, uma série de instituições em nosso País passou a adotá-los. Apesar de termos conhecimento dos dados referentes a evolução dos pacientes protocolados no GBTLI e dos demais estudos divulgados pelas instituições de origem, não tínhamos, porém, uma avaliação epidemiológica nem o conhecimento dos índices de sobrevivência alcançados no estado do Rio Grande do Sul. Neste trabalho foram avaliados 1472 pacientes com LLA, 833 (56,59%) do sexo masculino, 639 (43,41%) do sexo feminino, com idades entre zero e 20 anos, média de 7,40 anos (desvio padrão 5,14) e mediana de 5,70 anos (amplitude 0,06 a 20,76), no período de 1980 a 2008 provenientes deste Estado. Os dados foram colhidos individualmente dos prontuários dos pacientes admitidos nas principais instituições hospitalares que mantém assistência a pacientes pediátricos com neoplasias hematológicas. No presente estudo 487 pacientes (39,40%) foram registrados oficialmente nos protocolos do GBTLI; 678 (54,85%) receberam tratamento baseados nos regimes do grupo BFM e 71 (5,75%) por outros regimes incluindo os tratados segundo o protocolo UKALL. Os casos não foram, no entanto, protocolados e, na grande maioria não foram observados a totalidade dos itens exigidos para os pacientes registrados oficialmente. A sobrevida livre de eventos dos pacientes protocolados foi significativamente superior comparada aos não protocolados, 62,41% ± 2,43% e 53,86% ± 2,04% respectivamente, em cinco anos. De acordo com a faixa etária os pacientes que apresentavam idade de 15 a 19 anos tiveram um índice de SLE de 37,98% ± 4,72% em cinco anos, inferior quando comparado aos de zero a 4 anos e 5 a 9 anos respectivamente: 62,78% ± 2,28% e 62,43% ± 2,84%. Foi observada, na população estudada, uma SG de 63,73% ± 1,49% e SLE de 57,27% ± 1,57%, o que sugere uma discussão para implementar projetos com a finalidade de elevar estes índices de sobrevida. Epidemiologicamente a incidência da LLA com progenitores B seguiu o padrão observado em países desenvolvidos com um pico de freqüência absoluta entre as idades de 2 a 4 anos. Houve diferença significativa entre a população proveniente da região urbana ou rural sendo a SLE em cinco anos de 61,76% ± 1,76% e 49,81% ± 4,28% respectivamente. A SLE e a SG em lactentes e portadores de Síndrome de Down foi inferior aos resultados obtidos em instituições dos países desenvolvidos o que torna aconselhável uma revisão das condições para a assistência destes pacientes. Este estudo teve como finalidade principal retratar a situação passada e a atual do tratamento da LLA na infância e adolescência no Rio Grande do Sul e acumular dados aqui não interpretados e que poderão ser analisados posteriormente / Acute lymphocytic leukemia in childhood and adolescence is a neoplastic disease of lymphoid precursor of heterogeneous nature, being the first disseminated neoplasia to become curable through Chemotherapy. In Brazil, cooperative studies for the treatment of ALL started in 1980 with the creation of the first protocol by the Grupo Brasileiro para o Tratamento da Leucemia na Infância. According to these studies, Event Free Survival of 50%, 58% and 70% in the protocols of 1980, 1982 e 1985 respectively was observed. During the 80s and 90s many Brazilian institutions adopted the protocols motivated by the excellent results achieved by the Berlin Frankfurt Münster group. In spite of the knowledge provided by data related to the evolution of patients protocoled by the GBTLI and other studies published by medical institutions, there was not an epidemiologic evaluation or knowledge of survival indexes achieved in the state of Rio Grande do Sul. In this work, 1472 patients with ALL from the state of Rio Grande do Sul were evaluated. Among the subjects, 833 (56,59%) were male, 639 (43,41%) female, with age range between 0- 20 y average age of 7,40 (standard deviation 5,14) and median 5,70 years old (amplitude 0,06 to 20,76). Data was collected from the medical registers of patients with hematologic neoplasia in medical institutions, which offered pediatric assistance for ALL comprising the period between 1980 until 2008. In the present study, 487 patients (39,40%) were officially registered in the protocols of GBTLI; 678 (54,85%) received treatment based on the regime of the BFM group and 71 (5,75%) were treated according to other regimens (including the UKALL protocol). The cases, however, were not protocoled and, in most cases, the totality of items required for the patients registered officially were not observed. The EFS of the patients protocoled were significantly superior to those who were not protocoled (62,41% ± 2,43% and 53,86% ± 2,04% respectively) in five years. In respect to the age range, the patients which were between 15-20 years had an EFS index of 37,98% ± 4,72% in five years, which is inferior to the index of patients 0-4 years and 5-9 years: 62,78% ± 2,28% e 62,543± 2,84% respectively. An overall survival (OS) of 63,73% ± 1,49% and EFS of 57,27% ± 1,57% was observed in the population studied. These results indicate that a discussion for the implementation of projects, which can increase the indexes of cure, should be carried out. Epidemiologically, the incidence of ALL in B progenitors followed the pattern observed in developed countries with an absolute frequency peak in the age range of 2-4 years. The outcome was superior for patients coming from urban area in comparison to those from rural area. EFS and OS in infant and Down syndrome patients were inferior to the results obtained in developed countries, showing how important it is to review the conditions of the assistance provided to these patients. The objective of this work is to present the development of ALL treatment in childhood and adolescence in the state of Rio Grande do Sul, Brazil, from its beginning until the current days providing data, which can be analyzed and interpreted posteriorly

Cheng, Wai Hang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 76-88). / Abstract also in Chinese. / Acknowledgement --- p.i / 摘要 --- p.iii / List of Abbreviations --- p.iv / List of Figures --- p.vi / List of Tables --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- FE65 --- p.1 / Chapter 1.1.1 --- FE65 Protein Family and Their Structures --- p.2 / Chapter 1.1.1.2 --- PTB domains --- p.5 / Chapter 1.1.2 --- Expression Pattern of FE65 Proteins --- p.6 / Chapter 1.1.3 --- FE65 Family-Transgenic Animals --- p.7 / Chapter 1.1.4 --- Interacting Partners of FE65 --- p.8 / Chapter 1.1.4.1 --- "APP, APLPl and APLP2" --- p.9 / Chapter 1.1.4.2 --- LRP1 and ApoEr2 --- p.10 / Chapter 1.1.4.3 --- c-Abl --- p.11 / Chapter 1.1.4.4 --- Mena and EVL --- p.11 / Chapter 1.1.4.5 --- Tip60 --- p.12 / Chapter 1.1.4.6 --- SET --- p.12 / Chapter 1.1.4.7 --- Estrogen Receptor a --- p.13 / Chapter 1.1.4.8 --- Teashirt --- p.13 / Chapter 1.1.4.9 --- CP2/LSF/LBP1 --- p.13 / Chapter 1.1.4.10 --- Dexra sl --- p.14 / Chapter 1.1.4.11 --- P2X2-receptor subunit --- p.14 / Chapter 1.1.4.12 --- Tau --- p.15 / Chapter 1.1.4.13 --- Notchl --- p.15 / Chapter 1.1.4.14 --- Alcadein --- p.16 / Chapter 1.1.4.15 --- CD95/Fas/Apo -1 ligand --- p.16 / Chapter 1.1.4.16 --- p68 subunit of pre -mRNA cleavage and polyadenylation factor Im (p68 CFIm) --- p.17 / Chapter 1.1.4.17 --- Ataxinl --- p.17 / Chapter 1.1.5.1 --- FE65 as an adaptor protein --- p.20 / Chapter 1.1.5.2 --- FE65 and Alzheimer´ةs disease --- p.20 / Chapter 1.1.5.3 --- Transcriptional / Post-transcriptional regulation --- p.22 / Chapter 1.1.5.4 --- Apoptosis and cell cycle regulation --- p.23 / Chapter 1.1.5.5 --- Neuronal positioning and cell migration --- p.23 / Chapter 1.1.5.6 --- Learning and memory --- p.25 / Chapter 1.2 --- Objectives --- p.26 / Chapter Chapter 2 --- Investigation of the interaction between FE65 and Arf6 --- p.27 / Chapter 2.1 --- Materials --- p.27 / Chapter 2.1.1 --- DNA contructs --- p.27 / Chapter 2.1.2 --- Cell culture --- p.27 / Chapter 2.1.3 --- Immunoblotting --- p.28 / Chapter 2.1.4 --- Miscellaneous --- p.28 / Chapter 2.2 --- Methods --- p.29 / Chapter 2.2.1 --- Preparation of Escherichia coli competent cells --- p.29 / Chapter 2.2.2 --- DNA preparation with Intron Plasmid DNA --- p.30 / Chapter 2.2.3 --- DNA preparation with Macherey-Nagel NucleoBond Xtra Midi --- p.30 / Chapter 2.2.4 --- DNA preparation by the alkaline lysis method --- p.31 / Chapter 2.2.5 --- Spectrophotometric analysis of DNA --- p.32 / Chapter 2.2.6 --- Agarose gel electrophoresis --- p.32 / Chapter 2.2.7 --- Cell culture and transfection --- p.33 / Chapter 2.2.8 --- Bacterial GST-pull down assay --- p.33 / Chapter 2.2.9 --- GST-pull down assay for testing direct interaction between FE65 and Arf6 --- p.34 / Chapter 2.2.10 --- Mammalian GST-pull down assay --- p.35 / Chapter 2.2.11 --- Immunoprecipitation --- p.36 / Chapter 2.2.12 --- SDS-PAGE --- p.36 / Chapter 2.2.13 --- Immunoblotting --- p.39 / Chapter 2.3 --- Results --- p.40 / Chapter 2.3.1 --- Interaction between Arf6 and FE65 --- p.40 / Chapter 2.3.2 --- Determination of the interacting domain of FE65 with Arf6 --- p.43 / Chapter 2.3.3 --- Determination if FE65 and Arf6 interact directly --- p.45 / Chapter Chapter 3 --- Production of Antisera against Arf6 and Immunostaining of FE65-Arf6 --- p.47 / Chapter 3.1 --- Materials --- p.47 / Chapter 3.1.1 --- Protein expression and purification --- p.47 / Chapter 3.1.2 --- Immunization and harvest of antisera --- p.48 / Chapter 3.1.3 --- Immunostaining --- p.48 / Chapter 3.2 --- Methods --- p.48 / Chapter 3.2.1 --- Protein expression and purification --- p.48 / Chapter 3.2.2 --- Bradford assay --- p.50 / Chapter 3.2.3 --- Immunization --- p.50 / Chapter 3.2.4 --- Antibody purification --- p.51 / Chapter 3.2.5 --- Immunostaining --- p.52 / Chapter 3.3 --- Results --- p.53 / Chapter 3.3.1 --- Recombinant Arf6 expression and purification --- p.53 / Chapter 3.3.2 --- Titering of antisera --- p.57 / Chapter 3.3.3 --- Determination of antisera specificity --- p.59 / Chapter Chapter 4 --- Discussion --- p.68 / Chapter Chapter 5 --- Future Perspectives --- p.73 / References --- p.76

This thesis work describes the role of Rab proteins in amyloid processing and clearance in different cell pathways. It also describes an experimental approach used to analyze the expression effects of Rab10 in amyloid beta production. Since the main theory behind neurodegeneration in Alzheimer's disease claims that high levels of amyloid beta 42 (Aβ42) molecules trigger widespread neuronal death, control of Aβ42 has been a main target in Alzheimer's disease research. In addition, several studies show increased levels of particular Rab proteins in Alzheimer's pathogenesis. However, no review consolidates current findings in neurodegeneration of Alzheimer's with Rab protein dysfunction. The first chapter of this thesis aims to address this need by providing a current review of Rab proteins associated with APP and neurodegeneration. The second chapter constitutes an experimental approach used to characterize the effects of Rab10 and Sar1A GTPases in APP and amyloid processing. We found that Rab10 expression does not affect APP production but significantly changes Aβ generation, particularly the toxic Aβ42 and Aβ42:40 ratio. On the other hand, we found no significant effect of Sar1A expression on either APP or amyloid beta generation. These findings partially confirm the work done by Kauwe et al (2015) and provide preliminary evidence for two potential targets for protective effects in neurodegeneration.

Polyketides are natural products with complex chemical structures and immense pharmaceutical potential that are synthesized via secondary metabolic pathways. The in-vitro synthesis of these molecules requires high supply of building blocks such as acetyl Co-enzyme A, and cofactors (adenosine triphosphate (ATP). These precursor and cofactor are synthesized from respective soluble enzymes. Owing to the expensive nature of the enzymes, it is important to immobilize enzymes to improve the process economics by enabling multiple uses of catalyst and improving overall productivity and robustness. The polymer-based particles of nano and submicron size have become attractive material for their role in the life sciences. With the advances in synthetic protocols of the microgels and commercial availability of many of the monomers, it is feasible to tune the properties of the particles as per the process requirement. The core shell microgel with functional shell allows high loading of ligands onto the microgel particles due to increased availability of functional group on the outer surface. The aim of the thesis thus was to study biochemical reactions on the smart microgels support using single (acetyl CoA synthetase (Acs)) and dual (pyruvate kinase (Pk) and L-lactic dehydrogenase (Ldh)) enzyme/s systems. The study indicated that the enzyme immobilization significantly depends on the enzyme, conjugation strategy and the support. The covalent immobilization provides rigidity to the enzyme structure as in case of Acs immobilized on PNIPAm-AEMA microgels but at the same time leads to loss in enzyme activity. Whereas, in the case of covalent immobilization of Ldh on microgel showed improved in enzyme activity. On the other hand adsorption of the enzyme via ionic interaction provide better kinetic profile of enzymes hence the membrane reactor was prepared using PNIPAm-PEI conjugates for acetyl CoA synthesis. The better outcome of work with PNIPAm-PEI resulted in its further evaluation for dual enzyme system. This work is unique in the view that the immobilization strategies were well adapted to immobilize single and dual enzymes to achieve stable bioconjugates for their respective applications in precursor biosynthesis (Acetyl Co enzyme A) and co-factor dependent processes (ACoA and ATP). The positive end results of microgels as the support (particles in solution and as the thin film (membrane)) opens further prospective to explore these systems for other precursor biomolecule production.

No description available.

Die Neubildung von Neuronen persistiert lebenslang in der Subgranularzellschicht des Hippocampus und der Subventrikularzone des Großhirns und wird als adulte Neuroge-nese bezeichnet. Es wird vermutet, dass diese beim erwachsenen Menschen einen rele-vanten Einfluss auf degenerative Veränderungen, verschiedene neurologische Krank-heitsbilder und auf die (Dys-)Funktion des Gedächtnisses hat. Im Tiermodell wurde eine Verringerung der Neurogenese nach chronischer Morphingabe nachgewiesen. Vorarbeiten zeigten einen Zusammenhang zwischen chronischem Heroinmissbrauch und reaktiver Astrogliose, Mikrogliose und einer vermehrten Expression des polysialylated neural cell adhesion molecule im humanen Hippocampus. Daraus leitet sich die Hypothese ab, dass chronischer Heroinmissbrauch, als Modell für eine Abhängigkeitserkrankung, einen Einfluss auf die adulte humane Neurogenese hat. Es wurden in Formalin fixierte Gewebeproben aus dem Hippocampus von Verstorbenen mit einer letalen Heroinintoxikation und mit bekanntem Heroinmissbrauch (n = 20) un-tersucht und mit einer nach Alter und Geschlecht angepassten Kontrollgruppe (n = 28) verglichen. Hierbei wurden spezifische Neurogenesemarker mittels immunhistochemi-scher Methoden angewendet und ausgewertet. Es bestand eine generell sehr geringe zelluläre Proliferationsrate und eine signifikante Reduktion Musashi-1 positiver neuro-naler Vorläuferzellen bei gleichzeitig unveränderter Anzahl Nestin positiver reifender und Calretinin positiver migrierender postmitotischer Neurone. Zudem wurde ein ver-ändertes Calretinin-Expressionsmuster als Hinweis auf eventuelle funktionelle neuronale Defizite bei Drogenabhängigen festgestellt. Der potentielle Einfluss von chronischem Heroinmissbrauch auf die adulte humane Neurogenese wird erstmals gezeigt. Die Ergebnisse weisen auf eine negative Beeinflus-sung im Stadium neuronaler Vorläuferzellen und der Zellfunktion migrierender Neurone in der Fallgruppe im Vergleich zu einer gesunden Kontrollgruppe hin. Diese Hemmung der Neurogenese könnte eine Erklärungsmöglichkeit für kognitive Defizite und Funktionsstörungen des Gedächtnisses infolge chronischen Drogenkonsums bieten und zugleich eine Bedeutung bei der Entstehung von Abhängigkeitserkrankungen haben. Insofern könnte sich hier ein Ansatzpunkt für zukünftige Therapiestrategien derartiger Erkrankungen oder ihrer Folgen bieten.

Die Bildung von Amyloidablagerungen ist ein Kennzeichen der Alzheimerschen Erkrankung. Hauptbestandteil dieser senilen Plaques sind sogenannte A beta Peptide, die durch proteolytische Prozessierung aus einem Vorläufermolekül (APP) gebildet werden. Die vorliegende Arbeit beschreibt die Klonierung des Meerschweinchen - APP. Diese cDNA-Sequenz zeigt auf DNA-Ebene eine Homologie zum Human-APP von ca. 90%, auf Proteinebene beträgt die Identität ca. 97 %. Damit wird ein weiterer experimenteller Beweis für die evolutionäre Konservierung des Amyloidvorläuferproteins in Säugetieren erbracht. APP mRNA wird in Meerschweinchen-Geweben ubiquitär exprimiert. Durch alternatives Spleißen wird ein zum Human-APP im wesentlichen ähnliches Isoformenmuster gebildet: Isoformen, welche eine Proteaseinhibitordomäne enthalten, werden dominierend in peripheren Organen exprimiert, dagegen ist im Zentralnervensystem das APP 695 mit über 60 % der Gesamttranskripte die bevorzugt exprimierte Isoform. Die klonierte cDNA des Meerschweinchen-APP wurde in prokaryontischen wie auch eukaryontischen Zellsystemen exprimiert. Dabei wurde die Eignung einer Anzahl von gegen Human-APP gewonnenen Antikörpern zur Detektion des Meerschweinchen-APP und seiner Prozessierungsprodukte gezeigt. Die Expression der neuronal dominierend exprimierten Isoform APP 695 des Meerschweinchen-APP in humanen Neuroblastom-Zellen zeigte keine Unterschiede hinsichtlich der APP-Prozessierung und A beta-Bildung im direkten Vergleich zu Human-APP 695. Die proteolytische Prozessierung des Proteins wurde durch Detektion der typischen Spaltprodukte in vivo (im Liquor) als auch in einem neu etablierten in vitro-Modell primär kultivierter neuronaler Zellen untersucht. Diese Zellkulturen wurden zunächst immunhistochemisch und biochemisch charakterisiert und als "mixed brain"-Typ mit einem hohen neuronalen Anteil beschrieben. Die Prozessierung des endogenen Meerschweinchen-APP in kultivierten Zellen führt dabei zur Bildung und Akkumulation aggregationsfähiger A beta - Peptide. Zur Detektion dieser Peptide wurde ein sensitiver Nachweis durch Western-Blot etabliert. Es wird damit ein Modellsystem für in vitro-Untersuchungen vorgeschlagen, welches ein Studium der Expression und Prozessierung des Amyloidvorläuferproteins unter angenähert physiologischen Bedingungen ermöglicht. / A beta peptides, the major component of neuritic plaques found in the brains of patients with Alzheimer’s disease, are derived by proteolytic processing from a larger precursor molecule (amyloid precursor protein - APP). A combination of PCR methods was used to clone and sequence APP cDNA from guinea pig (Cavia porcellus). Guinea pig APP exhibits extensive similarities to human APP in terms of primary structure, mRNA expression of differentially spliced isoforms as shown by Northern blot and RT-PCR analysis as well as proteolytic processing to amyloidogenic A beta peptides. In contrast to rat and mouse APP, guinea pig APP - recombinantly expressed in human neuroblastoma-cells - was processed indistinguishable from human APP thus excluding intrinsic sequence-specific factors influencing processing. Further studies were performed using newly established primary cell cultures of guinea pig neurons. Refined methods have been used to detect and characterize major proteolytic processing products of APP in vitro and in vivo. In conclusion, guinea pigs provide a model to study expression and processing of APP that closely resembles the physiological situation in humans and should, therefore, be important in elucidating potential strategies to prevent amyloid formation in Alzheimers Disease.

The venom of cone snails (predatory marine molluscs of the genus Conus) has yielded a rich source of novel neuroactive peptides or “conotoxins”. Conotoxins are bioactive peptides found in the venom duct of Conus spp. Like other neuropeptides, conotoxins are expressed as propeptides that undergo posttranslational proteolytic processing. Peptides derived from propeptides are typically cleaved at a pair of dibasic residues (Lys-Arg, Arg-Arg, Lys-Lys or Arg-Lys) by proteases found in secretory vesicles. However, many precursor peptides contain multiple sets of basic residues, suggesting that highly substrate specific or differentially expressed proteases can determine processing outcomes. As many of the substrate-specific proteases remain unidentified, predicting new bioactive peptides from cDNA sequences is presently difficult, if not impossible. In order to understand more about the substrate specificity of conotoxin substrate-specific proteases a characterisation study of one such endoprotease isolated from the venom duct of Conus textile was undertaken. The C. textile mollusc was chosen as a good source from which to isolate the endoprotease for two reasons; firstly, these cone shells are found in great abundance on the Great Barrier Reef (Queensland, Australia) and are readily obtainable and secondly, a number of conotoxin precursors and their cleavage products have been previously identified in the venom duct. In order to purify the endoprotease an activity-guided fractionation protocol that included a para-nitroanilide (p-NA) substrate assay was developed. The p-NA substrate mimicked the cleavage site of the conotoxin TxVIA, a member of the C. textile O-superfamily of toxins. The protocol included a number of chromatographic techniques including ion exchange, size-exclusion and reverse-phased HPLC and resulted in isolation of an active protease, termed Tex31, to >95% purity. The purification of microgram quantities of Tex31 made it possible to characterise the proteolytic nature of Tex31 and to further characterise the O-superfamily conopeptide propeptide cleavage site specificity. Specificity experiments showed Tex31 requires a minimum of four residues including a leucine in the P4 position (LNKR↓) for efficient substrate processing. The complete sequence of Tex31 was determined from cDNA. A BLAST search revealed Tex31 to have high amino acid sequence similarity to the CAP (abbreviated from CRISP (Cysteine-rich secretory protein), Antigen 5 and PR-1 (pathogenesis-related protein)) superfamily and most closely related to the CRISP family of mammalian and venom proteins that, like Tex31, have a cysteine-rich C-terminal domain. The CAP superfamily is widely distributed in the animal, plant and fungal kingdoms, and is implicated in processes as diverse as human brain tumour growth and plant pathogenesis. This is the first report of a biological role for the N-terminal domain of CAP proteins. A homology model of Tex31 constructed from two PR-1 proteins, Antigen 5 and P14a, revealed the highly conserved and likely catalytic residues, His78, Ser99 and Glu115. These three amino acids fall within a structurally conserved N-terminal domain found in all CAP proteins. It is possible that other CAP proteins are also substrate-specific proteases. With no homology to any known proteases, Tex31 may belong to a new class of protease. The sequence alignment of five Tex31-like proteins cloned from C. marmoreus, C. litteratus, C. arentus, C. planboris, and C. omaria show very high sequence similarity to Tex31 (~80%), but only one weakly conserved serine residue was identified when the conserved residues of the new Tex31-like protein sequences were aligned with members of the CAP superfamily. Future work to identify members of catalytic diad or triad, e.g. by site-directed mutagenesis, will rely on the expression of active recombinant Tex31. In this study neither Escherichia coli nor Pichia pastoris expression systems yielded active recombinant Tex31 protein, possibly due to the number of cysteine residues hindering the expression of correctly folded active Tex31. This study has shown Tex31 to be highly sequence specific in its cleavage site and it is likely that this high substrate specificity has confounded previous attempts to identify the proteolytic nature of other CAP proteins. With the proteolytic nature of one member of the CAP protein family confirmed, it is hoped this important discovery may lead the way to discovering the role of other CAP family members.

19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2117" Guodong Du. 12/19/2004. Report is also available in paper and microfiche from NTIS.