by Hiu Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1991. / Includes bibliographical references. / SUMMARY --- p.1 / INTRODUCTION --- p.4 / LITERATURE REVIEW --- p.8 / Chapter I. --- Nasopharyngeal carcinoma (NPC) --- p.8 / Chapter A. --- Epidemiology of NPC --- p.8 / Chapter B. --- Anatomy of NPC --- p.11 / Chapter C. --- Pathology of NPC --- p.12 / Chapter D. --- Histological classification of NPC --- p.14 / Chapter E. --- Stage classification of NPC --- p.15 / Chapter F. --- Clinical feature of NPC --- p.18 / Chapter G. --- Diagnosis of NPC --- p.19 / Chapter (a) --- Clinical examination / Chapter (b) --- Radiographic examination / Chapter (c) --- Laboratory examination / Chapter (d) --- Biopsy examination / Chapter H. --- Treatment of NPC --- p.21 / Chapter (a) --- Surgery / Chapter (b) --- Chemotherapy / Chapter (c) --- Radiotherapy / Chapter I. --- Prognosis of NPC --- p.23 / Chapter J. --- Etiology of NPC --- p.24 / Chapter (a) --- Dietary factor / Chapter (b) --- Genetic factor / Chapter (c) --- Environmental factor / Chapter (d) --- EBV infection / Chapter (e) --- Others / Chapter II. --- Beta-2 Microglobulin (B2M) --- p.30 / Chapter A. --- Structure and function of B2M --- p.30 / Chapter B. --- Clinical chemistry of B2M --- p.33 / Chapter C. --- B2M and its relationship to immunogenetic system --- p.34 / Chapter D. --- B2M in solid malignancies --- p.35 / Chapter E. --- B2M in hematologic malignancies --- p.36 / Chapter F. --- B2M in non-malignant diseases --- p.38 / Chapter III. --- Epstein - Barr Virus (EBV) --- p.41 / Chapter A. --- Morphology / Chapter B. --- EBV infection --- p.42 / Chapter C. --- EBV and Nasopharyngeal Carcinoma --- p.44 / Chapter D. --- Relationship of EBV to other human disease --- p.46 / Chapter (a) --- The relationship of EBV to IM / Chapter (b) --- The relationship of EBV to BL / Chapter E. --- EBV genome-carrying lymphoid cell lines --- p.50 / Chapter IV. --- TUMOUR ANTIGEN OF SQUEMOUS CELL CARCINOMA --- p.55 / Chapter A. --- The source of TA-4 --- p.55 / Chapter B. --- Characteristics of TA-4 --- p.56 / Chapter C. --- TA-4 in squamous cell carcinoma of uterine cervix --- p.57 / Chapter D. --- TA-4 in other type of squamous cell carcinaoma --- p.58 / MATERIALS AND METHODS / Chapter A. --- Materials --- p.61 / Chapter B. --- Measurement of Beta-2 Microglobulin --- p.63 / Chapter (a) --- Principles / Chapter (b) --- Assay protocol / Chapter (c) --- Reproducibility / Chapter C. --- Detection of EBV antibody titres in human sera --- p.68 / Chapter (a) --- Induction of EA/VCA in Raji/P3HR-1 cell lines / Chapter (b) --- Detection of antibody titres to EA/VCA in human sera / Chapter D. --- Measurement of squamous cell carcinoma associated antigen --- p.75 / RESULTS --- p.79 / Chapter A. --- Diurnal change of serum B2M or TA-4 level --- p.79 / Chapter B. --- The B2M and TA-4 levels in apparently healthy people --- p.81 / Chapter C. --- The usefullness of assay in initial diagnosis and staging --- p.81 / Chapter (a) --- Correlation between serum B2M levels and staging of NPC / Chapter (b) --- Correlation between serum TA-4 levels and staging of NPC / Chapter D. --- Correlation between histological differentiation of NPC and B2M and TA-4 level --- p.91 / Chapter E. --- The usefulness of assay for monitoring the NPC --- p.93 / Chapter (a) --- patients achieved completed remission / Chapter (b) --- patients developed local recurrence / Chapter (c) --- patients developed distant metastases / DISCUSSION --- p.131 / Chapter A. --- Serum B2M in NPC patients --- p.131 / Chapter B. --- Serum TA-4 in NPC ptients --- p.136 / Chapter C. --- EBV antibody titres in NPC patients --- p.137 / Chapter D. --- Conclusion --- p.141 / Chapter E. --- Suggested further study --- p.143 / REFERENCES --- p.146

Thesis (Ph. D.)--University of Missouri--Columbia, 1996. / "December 1996." Typescript. Vita. Includes bibliographical references (leaves [128]-155). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri--Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves : [128]-155). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 196-228).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

La Beta-2-microglobuline est une protéine de 12kDa, impliquée dans une maladie dûe à un mauvais repliement: l'amylose liée à la dialyse. Elle constitue donc un modèle pour la formation de fibrilles amyloides et pour le repliement des protéines. La B2M est un objet à la fois difficile et fructueux à étudier. La production de B2M est complexe et demande une optimisation important pour obtenir une protéine correctement repliée et atteindre des rendements approprié pour des études de RMN et SAXS. Le repliement de la B2M est sensible au solvent, à la température, à la concentration et souvent aux conditions de préparation. Pourtant notre étude, à l'aide de plusieurs méthodes biophysiques, a pu révéler plusieurs faits essentiels de son mécanisme de repliement et de la structure et propriétés des intermédiaires. Un premier résultat est que le repliement et l'oligomérisation sont deux processus concourants. Une découverte majeure est l'existence d'un équilibre monomère oligomère entre deux états I1 et I2 intermédiaires du repliement. Détecté indirectement à l'aide de RMN temps réel comme SOFAST, I2 a été directement charactérisé en SAXS: Il s'agit probablement d'un dimère. Les états intermédiaires de repliement de B2M avaient été pointés comme favorisant la formation de fibrilles: cela s'explique facilement avec l'existence d'un intermédiaire dimérique. Une combinaison de méthodes biophysiques permet la caractérisation de cet équilibre monomère-oligomère. En SAXS, puis confirmé en RMN, la stoichiométrie de l'équilibre est celle d'un monomère-dimère. Des travaux complémentaires utilisant les techniques développées pour cette étude pourront servir à caractériser plus finement cet équilibre. L'étude approfondie du repliement de B2M pousse les techniques biophysiques dans leurs retranchements: la sensibilité et le temps d'acquisition pour la RMN, la polydispersité pour le SAXS. Pourtant dans les deux cas un grand oligomère I3, qui disparait en quelques minutes, a pu être détecté, ce qui fut confirmé par UV-Fluo. La caractérisation d'I3 demandera des dévelopements méthodologiques supplémentaires, ainsi qu'un nouveau plan d'expérience. D'autres méthodes comme la spectrométrie de masse nano-ESI pourraient représenter des sources d'information utiles. S'attaquer aux limites des méthodes biophysiques pousse au développement méthodologique. Ainsi pour étudier la structure et dynamique d'I1, la méthode d'acquisition continue des données a permis l'attribution des résonnances de cette espèce qui a une demi vie de quelques dizaines de minutes. Un échange conformationnel a été découvert pour l'état I1 du mutant W60G, en développant une méthode de relaxation RMN: R2-BEST-TROSY. Les méthodes développées pour cette étude pourront servir des études sur le repliement d'autres protéines, mais aussi dans d'autres contextes où la demi-vie des objets étudiés est courte, comme dans les expérience RMN intracellulaires. Cette étude est évidemment éloignée d'une application directe dans le combat contre les maladies du mauvais repliement des protéines. Pour autant, la découverte d'états intermédiaires oligomériques souligne que l'oligomérisation et le repliement ne devraient pas être étudiés séparément, mais sont des processus liés. Les développements méthodologiques de cette étude pourront aussi être appliqués à d'autres protéines comme à d'autres contexte. Il est donc permis d'espérer que ces questionnements et développements permettront d'avancer vers une meilleure compréhension de ces maladies. / Beta-2-microglobulin is a 12kDa protein, involved in a misfolding disease: dialysis related amyloidosis. It is therefore a model for amyloid fibril formation and protein folding studies. B2M is both a fruitful and difficult object of study. B2M production is complex, requiring optimization to obtain a well folded protein and reach yields suitable to NMR and SAXS studies. B2M folding is highly sensitive on buffer, temperature, concentration and often preparation conditions. Yet our studies, using several biophysical methods, revealed several essential facts of the folding mechanism and of the structure and dynamics of folding intermediates. A first outcome of our studies is that folding and oligomerization are co-existing processes. A major finding is the existence of a monomer-oligomer equilibrium between I1 and I2 folding intermediate states. Indirectly detected using real time NMR methods like SOFAST, I2 was directly detected and characterized using SAXS: I2 is likely to be a dimer. Folding intermediate states of B2M had been shown to favor fibril formation: this is easily explained by the existence of a dimeric folding intermediate state with an important population. A combination of biophysical methods allows the characterization of this monomer-oligomer equilibrium. Using SAXS, and later confirmed by NMR relaxation experiments, stoichiometry is shown to be a monomer-dimer equilibrium. Further work based on the methodology applied to the folding of the W60G-B2M mutant, including a further optimization of the sensitivity of the experiment, will give a sharper picture of the I1-I2 equilibrium for the WT protein, and may provide information on the timescale of the equilibrium. The thorough study of the folding of B2M pushes biophysical methods to their limits: sensitivity and acquisition time for NMR, polydispersity for SAXS. Yet in both cases a large oligomer (I3) that disappears within minutes was detected, and confirmed using UV-fluo. Characterization of I3 will demand further methodological developments, a new experimentation plan including a full dilution scale, or double jump experiments, for example. A question that arises is the comparison of this large oligomer and oligomeric intermediate states that are populated during the formation of fibrils. Other biophysical methods, such as ESI mass spectroscopy, may be an interesting input. Tackling the limits of biophysical methods leads to methodological developments. For example, to study the structure and dynamics of I1, the continuous data acquisition method allowed the assignment of this species that has a half-lifetime of tens of minutes. A conformational exchange was discovered for the I1 state of the W60G-B2M mutant, through the development of a spin relaxation measurement experiment: R2-BEST-TROSY. The methods developed for this study may be later used to study the folding and folding intermediate states of other proteins, such as alpha-lactalbumin , or in other contexts in which the short lifetime of the protein is an issue, as for in-cell NMR experiments. Our studies are of course far from an application or a concrete result in the fight against misfolding diseases such as dialysis related amyloidosis or Parkinson's. But the discovery of oligomeric folding intermediate states underlines that oligomerization (including fibril formation) and folding should not be studied separately, and are processes that are closely related. Methodological developments included in our work can be applied to other proteins as well as other contexts. Hopefully these questionings and developments will constitute a step forward a better understanding of this diseases.

Aims: The purpose of the research was to investigate the benefits of a hereditary colorectal cancer registry in the management of patients and families with Lynch syndrome. In study one, a systematic review was performed to quantify the impact of registration and screening on colorectal cancer (CRC) incidence and mortality, with comparison between familial adenomatous polyposis (FAP) and Lynch syndrome (LS). In study two, a regional Lynch syndrome registry was utilised to evaluate the uptake of predictive testing and colorectal screening among first-degree relatives (FDRs) and investigate novel methods for engaging at-risk relatives, including an enhanced role for the general practitioner (GP). In study three, the registry was used to investigate proposed associations between Lynch syndrome and prostate and bladder cancer. In study four, mismatch repair-deficient (dMMR) CRCs from Lynch syndrome patients and randomised-controlled trials (RCTs) were used to evaluate a novel prognostic biomarker, beta-2 microglobulin (B2M). Methods: An electronic database search was conducted to identify studies describing CRC incidence and/or mortality in FAP or LS, with comparison of either: 1) screened and unscreened patients or 2) patients ‘before and after’ establishment of the registry. Using the Manchester regional Lynch syndrome registry database, the uptake of predictive testing and colorectal screening among FDRs was assessed with Kaplan-Meier analysis. Novel strategies for improving engagement were explored via a patient advisory group discussion and a regional primary care questionnaire. Cases of prostate and bladder cancer in male mutation carriers and their male FDRs were identified, and cumulative and relative risks were calculated, using expected rates from cancer registry data. DNA from 350 dMMR CRC specimens from Lynch syndrome patients and RCTs were tested for B2M mutations using Sanger sequencing, and correlated with clinical outcome. Results: 43 studies were included in the systematic review (33 FAP; 10 Lynch). Registry-based screening was associated with a significant reduction in CRC incidence and in Lynch syndrome, CRC-related mortality was negligible in those undergoing surveillance. 242 Lynch syndrome families were recorded on the Manchester Lynch syndrome registry. 329 of 591 (55.7%) eligible FDRs had undergone predictive testing. Uptake was significantly lower in males and younger age groups (<25 yrs). Compliance with colorectal screening was excellent following a mutation positive predictive test but poor in untested individuals (97.3% vs 35.0%). Eight prostate cancers were identified in 821 male LS mutation carriers and male FDRs. MSH2 mutation carriers had a ten-fold increased risk of prostate cancer (RR 10.41; 95%CI 2.80, 26.65) but no association with bladder cancer was identified. 69/286 (24.1%) of dMMR CRCs contained significant B2M mutations. B2M mutations were associated with complete absence of recurrence (0/39) during follow-up in the QUASAR trial (stage II), compared with 14/77 (18.2%) in wild-type B2M (p=0.005). Conclusion: Studies consistently report that registration and screening result in a reduction of CRC incidence and mortality in FAP and LS (Level 2a evidence, Grade B recommendation). Funding and managerial support for registries should be made available. Uptake of predictive testing and colorectal screening in Lynch syndrome could be substantially improved, particularly among males and younger age groups, but this requires advances in communication with at-risk relatives. It is unlikely that GPs will actively participate without considerable support from genetics services. A trial of PSA screening in MSH2 mutation carriers from 50 years would be appropriate. B2M mutation status has potential clinical utility as a prognostic biomarker in stage II dMMR CRC.

A nefropatia diabética (ND) é uma das principais causas de doença renal terminal. Além da lesão glomerular, o compartimento tubulointersticial é afetado no desenvolvimento da ND, não somente pela proteinúria como pelos efeitos pró-inflamatórios, profibróticos, pró-oxidantes e angiogênicos da hiperglicemia e dos produtos finais de glicação avançada (AGEs). Sabese que as concentrações de marcadores do estresse oxidativo estão aumentadas em pacientes com diabetes mellitus (DM). O sistema tiorredoxina (TXN) é um dos principais sistemas antioxidantes endógenos. A TXN é capaz de interagir com um grande número de fatores de transcrição e proteínas, tal como a Thioredoxin interacting protein (TXNIP) que tem sido reconhecida na patogênese do DM e de suas complicações. Além da TXNIP, a deficiência de tiamina, ou vitamina B1, já foi relatada em modelos experimentais de DM, concomitantemente a um aumento de seu clearance renal. Os transportadores de tiamina 1 (THTR1) e 2 (THTR2) (codificados pelos genes SLC19A2 e SLC19A3, respectivamente) são os responsáveis pela reabsorção de tiamina no túbulo proximal após sua filtração pelo glomérulo. Estudos já demonstraram que a excreção aumentada de tiamina pode ser um fator de risco para o declínio precoce da função renal em pacientes DM. Uma outra proteína de interesse é a beta 2 microglobulina (B2M), expressa em situações que cursam com inflamação, um fenômeno bem caracterizado na tubulopatia diabética. O estudo da ativação intrarenal de vias potencialmente associadas à evolução da ND em humanos é dificultada pela necessidade de biópsia renal. Recentemente o sedimento urinário tem sido utilizado na avaliação das doenças renais, tanto na tentativa de identificar biomarcadores que possam predizer o declínio da função renal, como para o melhor entendimento da patogênese dessa complicação. O objetivo deste trabalho foi estudar a participação dos genesalvo TXNIP, TXN, SLC19A2, SLC19A3 e B2M na patogênese da ND em portadores de DM1. Estudamos o RNA mensageiro (mRNA) do sedimento urinário de pacientes DM1 (n=55), portadores de glomeruloesclerose segmentar e focal (GESF, um modelo de nefropatia não diabética, n=12) e de indivíduos controles (n=11) para avaliação da expressão dos genes-alvo, e sua associação com as manifestações da ND. Também foi extraído mRNA de células linfomononucleares de pacientes DM1 (n=162) e indivíduos controles (n=26) para comparação com os resultados obtidos no sedimento urinário e foram dosadas as concentrações plasmáticas de tiamina em um subgrupos de pacientes DM1 e de indivíduos controles. Além disso, uma linhagem de células renais humanas foi tratada com altas concentrações de glicose e albumina glicada ou não glicada in vitro para avaliar se os AGEs estão implicados na alteração de expressão dos genes-alvos. Como resultado observamos (1) um aumento na expressão de TXNIP e TXN no sedimento urinário de pacientes DM1 com doença renal e associação da expressão de TXNIP com a magnitude do declínio da taxa de filtração glomerular; (2) um aumento na expressão de TXNIP e TXN nas células linfomononucleares dos pacientes DM1; (3) um aumento na expressão de SLC19A2 no sedimento urinário de pacientes DM1 com doença renal; (4) uma diminuição nas concentrações plasmáticas de tiamina nos pacientes DM1 em comparação aos controles; (5) um aumento na expressão de B2M no sedimento urinário de pacientes DM1 com doença renal e (6) um aumento na expressão de TXNIP e B2M nas células renais humanas tratadas concomitantemente com altas concentrações de glicose e albumina glicada. Os resultados do presente estudo sugerem fortemente a participação do sistema TXN e da B2M na etiopatogênese da ND / Diabetic nephropathy (DN) is a major cause of end stage renal disease. Glomerular and tubulointerstitial compartments are affected not only by proteinuria but also by the pro-inflammatory, profibrotic, pro-oxidants and pro-angiogenic effects exerted by hyperglycemia and advanced glycation end products (AGEs) in the development of DN. It is well known that concentrations of oxidative stress markers are increased in patients with diabetes mellitus (DM). The thioredoxin system (TXN) is one of the majors endogenous antioxidant systems; TXN molecule is able to interact with a large number of transcription factors and proteins such as Thioredoxin interacting protein (TXNIP), which has been recognized in the pathogenesis of DM and its complications. Deficiency of thiamine, or B1 vitamin, has been reported in experimental models of DM concomitantly with an increase in its renal clearance. Thiamine transporter 1 (THTR1), encoded by the SLC19A2 gene and Thiamine transporter 2 (THTR2), encoded by the SLC19A3 gene are responsible for thiamine reabsorption in the proximal tubule after glomerular filtration. Studies have shown that increased urinary excretion of thiamine may be a risk predictor for an early decline in kidney function in diabetic patients. Another protein of interest is beta-2-microglobulin (B2M), expressed in situations of inflammation, a well-characterized phenomenon in diabetic tubulopathy. The study of activation or inactivation of intrarenal pathways potentially associated with progression of DN in humans is complicated by the need for renal biopsy. Recently urinary sediment has been used in the evaluation of kidney diseases in an attempt to identify biomarkers that can predict kidney function decline and as a tool for a better understanding of the pathogenesis of this complication. The objective of this work was to study the participation of the target genes TXNIP, TXN, SLC19A2, SLC19A3 and B2M in the pathogenesis of DN in type 1 DM (T1D) patients. We studied the urinary sediment messenger RNA (mRNA) from patients with T1D (n=55); with focal and segmental glomerulosclerosis (FSGS, a non diabetic nephropathy model, n=12) and from control subjects (n=11) to assess the expression of the target genes and their association with the severity of DN. We also studied the mRNA expression of peripheral lymphomononuclear (PLMN) cells from T1D patients (n=162) and control subjects (n=26) in order to compare with the results obtained in the urinary sediment. Plasmatic concentrations of thiamine were also measured in a subgroup of T1D patients and control subjects. In addition, a lineage of human kidney cells was exposed to high glucose concentrations and to glycated and non-glycated albumin to evaluate if AGEs are implicated in the modulation of expression of the target genes. As a result we found that (1) TXNIP and TXN are upregulated in the urinary sediment of T1D patients with kidney disease and TXNIP is associated with the magnitude of glomerular filtration rate decline; (2) TXNIP and TXN are upregulated in PLMN cells from T1D patients; (3) SLC19A2 is upregulated in the urinary sediment of T1D patients with kidney disease; (4) T1D patients present decreased plasmatic thiamine concentrations compared to control subjects; (5) B2M is upregulated in the urinary sediment of T1D patients with kidney disease and (6) TXNIP and B2M are upregulated in human kidney cells exposed concomitantly to high glucose concentrations and glycated albumin. The results of the present study strongly suggest the participation of the TXN system and of B2M in the pathogenesis of DN. Descriptors: diabetes mellitus, diabetic nephropathies, urine, glycosylation end products, advanced, thiamine, thioredoxins, beta 2-microglobulin Diabetic nephropathy (DN) is a major cause of end stage renal disease. Glomerular and tubulointerstitial compartments are affected not only by proteinuria but also by the pro-inflammatory, profibrotic, pro-oxidants and pro-angiogenic effects exerted by hyperglycemia and advanced glycation end products (AGEs) in the development of DN. It is well known that concentrations of oxidative stress markers are increased in patients with diabetes mellitus (DM). The thioredoxin system (TXN) is one of the majors endogenous antioxidant systems; TXN molecule is able to interact with a large number of transcription factors and proteins such as Thioredoxin interacting protein (TXNIP), which has been recognized in the pathogenesis of DM and its complications. Deficiency of thiamine, or B1 vitamin, has been reported in experimental models of DM concomitantly with an increase in its renal clearance. Thiamine transporter 1 (THTR1), encoded by the SLC19A2 gene and Thiamine transporter 2 (THTR2), encoded by the SLC19A3 gene are responsible for thiamine reabsorption in the proximal tubule after glomerular filtration. Studies have shown that increased urinary excretion of thiamine may be a risk predictor for an early decline in kidney function in diabetic patients. Another protein of interest is beta-2-microglobulin (B2M), expressed in situations of inflammation, a well-characterized phenomenon in diabetic tubulopathy. The study of activation or inactivation of intrarenal pathways potentially associated with progression of DN in humans is complicated by the need for renal biopsy. Recently urinary sediment has been used in the evaluation of kidney diseases in an attempt to identify biomarkers that can predict kidney function decline and as a tool for a better understanding of the pathogenesis of this complication. The objective of this work was to study the participation of the target genes TXNIP, TXN, SLC19A2, SLC19A3 and B2M in the pathogenesis of DN in type 1 DM (T1D) patients. We studied the urinary sediment messenger RNA (mRNA) from patients with T1D (n=55); with focal and segmental glomerulosclerosis (FSGS, a non diabetic nephropathy model, n=12) and from control subjects (n=11) to assess the expression of the target genes and their association with the severity of DN. We also studied the mRNA expression of peripheral lymphomononuclear (PLMN) cells from T1D patients (n=162) and control subjects (n=26) in order to compare with the results obtained in the urinary sediment. Plasmatic concentrations of thiamine were also measured in a subgroup of T1D patients and control subjects. In addition, a lineage of human kidney cells was exposed to high glucose concentrations and to glycated and non-glycated albumin to evaluate if AGEs are implicated in the modulation of expression of the target genes. As a result we found that (1) TXNIP and TXN are upregulated in the urinary sediment of T1D patients with kidney disease and TXNIP is associated with the magnitude of glomerular filtration rate decline; (2) TXNIP and TXN are upregulated in PLMN cells from T1D patients; (3) SLC19A2 is upregulated in the urinary sediment of T1D patients with kidney disease; (4) T1D patients present decreased plasmatic thiamine concentrations compared to control subjects; (5) B2M is upregulated in the urinary sediment of T1D patients with kidney disease and (6) TXNIP and B2M are upregulated in human kidney cells exposed concomitantly to high glucose concentrations and glycated albumin. The results of the present study strongly suggest the participation of the TXN system and of B2M in the pathogenesis of DN

A nefropatia diabética (ND) é uma das principais causas de doença renal terminal. Além da lesão glomerular, o compartimento tubulointersticial é afetado no desenvolvimento da ND, não somente pela proteinúria como pelos efeitos pró-inflamatórios, profibróticos, pró-oxidantes e angiogênicos da hiperglicemia e dos produtos finais de glicação avançada (AGEs). Sabese que as concentrações de marcadores do estresse oxidativo estão aumentadas em pacientes com diabetes mellitus (DM). O sistema tiorredoxina (TXN) é um dos principais sistemas antioxidantes endógenos. A TXN é capaz de interagir com um grande número de fatores de transcrição e proteínas, tal como a Thioredoxin interacting protein (TXNIP) que tem sido reconhecida na patogênese do DM e de suas complicações. Além da TXNIP, a deficiência de tiamina, ou vitamina B1, já foi relatada em modelos experimentais de DM, concomitantemente a um aumento de seu clearance renal. Os transportadores de tiamina 1 (THTR1) e 2 (THTR2) (codificados pelos genes SLC19A2 e SLC19A3, respectivamente) são os responsáveis pela reabsorção de tiamina no túbulo proximal após sua filtração pelo glomérulo. Estudos já demonstraram que a excreção aumentada de tiamina pode ser um fator de risco para o declínio precoce da função renal em pacientes DM. Uma outra proteína de interesse é a beta 2 microglobulina (B2M), expressa em situações que cursam com inflamação, um fenômeno bem caracterizado na tubulopatia diabética. O estudo da ativação intrarenal de vias potencialmente associadas à evolução da ND em humanos é dificultada pela necessidade de biópsia renal. Recentemente o sedimento urinário tem sido utilizado na avaliação das doenças renais, tanto na tentativa de identificar biomarcadores que possam predizer o declínio da função renal, como para o melhor entendimento da patogênese dessa complicação. O objetivo deste trabalho foi estudar a participação dos genesalvo TXNIP, TXN, SLC19A2, SLC19A3 e B2M na patogênese da ND em portadores de DM1. Estudamos o RNA mensageiro (mRNA) do sedimento urinário de pacientes DM1 (n=55), portadores de glomeruloesclerose segmentar e focal (GESF, um modelo de nefropatia não diabética, n=12) e de indivíduos controles (n=11) para avaliação da expressão dos genes-alvo, e sua associação com as manifestações da ND. Também foi extraído mRNA de células linfomononucleares de pacientes DM1 (n=162) e indivíduos controles (n=26) para comparação com os resultados obtidos no sedimento urinário e foram dosadas as concentrações plasmáticas de tiamina em um subgrupos de pacientes DM1 e de indivíduos controles. Além disso, uma linhagem de células renais humanas foi tratada com altas concentrações de glicose e albumina glicada ou não glicada in vitro para avaliar se os AGEs estão implicados na alteração de expressão dos genes-alvos. Como resultado observamos (1) um aumento na expressão de TXNIP e TXN no sedimento urinário de pacientes DM1 com doença renal e associação da expressão de TXNIP com a magnitude do declínio da taxa de filtração glomerular; (2) um aumento na expressão de TXNIP e TXN nas células linfomononucleares dos pacientes DM1; (3) um aumento na expressão de SLC19A2 no sedimento urinário de pacientes DM1 com doença renal; (4) uma diminuição nas concentrações plasmáticas de tiamina nos pacientes DM1 em comparação aos controles; (5) um aumento na expressão de B2M no sedimento urinário de pacientes DM1 com doença renal e (6) um aumento na expressão de TXNIP e B2M nas células renais humanas tratadas concomitantemente com altas concentrações de glicose e albumina glicada. Os resultados do presente estudo sugerem fortemente a participação do sistema TXN e da B2M na etiopatogênese da ND / Diabetic nephropathy (DN) is a major cause of end stage renal disease. Glomerular and tubulointerstitial compartments are affected not only by proteinuria but also by the pro-inflammatory, profibrotic, pro-oxidants and pro-angiogenic effects exerted by hyperglycemia and advanced glycation end products (AGEs) in the development of DN. It is well known that concentrations of oxidative stress markers are increased in patients with diabetes mellitus (DM). The thioredoxin system (TXN) is one of the majors endogenous antioxidant systems; TXN molecule is able to interact with a large number of transcription factors and proteins such as Thioredoxin interacting protein (TXNIP), which has been recognized in the pathogenesis of DM and its complications. Deficiency of thiamine, or B1 vitamin, has been reported in experimental models of DM concomitantly with an increase in its renal clearance. Thiamine transporter 1 (THTR1), encoded by the SLC19A2 gene and Thiamine transporter 2 (THTR2), encoded by the SLC19A3 gene are responsible for thiamine reabsorption in the proximal tubule after glomerular filtration. Studies have shown that increased urinary excretion of thiamine may be a risk predictor for an early decline in kidney function in diabetic patients. Another protein of interest is beta-2-microglobulin (B2M), expressed in situations of inflammation, a well-characterized phenomenon in diabetic tubulopathy. The study of activation or inactivation of intrarenal pathways potentially associated with progression of DN in humans is complicated by the need for renal biopsy. Recently urinary sediment has been used in the evaluation of kidney diseases in an attempt to identify biomarkers that can predict kidney function decline and as a tool for a better understanding of the pathogenesis of this complication. The objective of this work was to study the participation of the target genes TXNIP, TXN, SLC19A2, SLC19A3 and B2M in the pathogenesis of DN in type 1 DM (T1D) patients. We studied the urinary sediment messenger RNA (mRNA) from patients with T1D (n=55); with focal and segmental glomerulosclerosis (FSGS, a non diabetic nephropathy model, n=12) and from control subjects (n=11) to assess the expression of the target genes and their association with the severity of DN. We also studied the mRNA expression of peripheral lymphomononuclear (PLMN) cells from T1D patients (n=162) and control subjects (n=26) in order to compare with the results obtained in the urinary sediment. Plasmatic concentrations of thiamine were also measured in a subgroup of T1D patients and control subjects. In addition, a lineage of human kidney cells was exposed to high glucose concentrations and to glycated and non-glycated albumin to evaluate if AGEs are implicated in the modulation of expression of the target genes. As a result we found that (1) TXNIP and TXN are upregulated in the urinary sediment of T1D patients with kidney disease and TXNIP is associated with the magnitude of glomerular filtration rate decline; (2) TXNIP and TXN are upregulated in PLMN cells from T1D patients; (3) SLC19A2 is upregulated in the urinary sediment of T1D patients with kidney disease; (4) T1D patients present decreased plasmatic thiamine concentrations compared to control subjects; (5) B2M is upregulated in the urinary sediment of T1D patients with kidney disease and (6) TXNIP and B2M are upregulated in human kidney cells exposed concomitantly to high glucose concentrations and glycated albumin. The results of the present study strongly suggest the participation of the TXN system and of B2M in the pathogenesis of DN. Descriptors: diabetes mellitus, diabetic nephropathies, urine, glycosylation end products, advanced, thiamine, thioredoxins, beta 2-microglobulin Diabetic nephropathy (DN) is a major cause of end stage renal disease. Glomerular and tubulointerstitial compartments are affected not only by proteinuria but also by the pro-inflammatory, profibrotic, pro-oxidants and pro-angiogenic effects exerted by hyperglycemia and advanced glycation end products (AGEs) in the development of DN. It is well known that concentrations of oxidative stress markers are increased in patients with diabetes mellitus (DM). The thioredoxin system (TXN) is one of the majors endogenous antioxidant systems; TXN molecule is able to interact with a large number of transcription factors and proteins such as Thioredoxin interacting protein (TXNIP), which has been recognized in the pathogenesis of DM and its complications. Deficiency of thiamine, or B1 vitamin, has been reported in experimental models of DM concomitantly with an increase in its renal clearance. Thiamine transporter 1 (THTR1), encoded by the SLC19A2 gene and Thiamine transporter 2 (THTR2), encoded by the SLC19A3 gene are responsible for thiamine reabsorption in the proximal tubule after glomerular filtration. Studies have shown that increased urinary excretion of thiamine may be a risk predictor for an early decline in kidney function in diabetic patients. Another protein of interest is beta-2-microglobulin (B2M), expressed in situations of inflammation, a well-characterized phenomenon in diabetic tubulopathy. The study of activation or inactivation of intrarenal pathways potentially associated with progression of DN in humans is complicated by the need for renal biopsy. Recently urinary sediment has been used in the evaluation of kidney diseases in an attempt to identify biomarkers that can predict kidney function decline and as a tool for a better understanding of the pathogenesis of this complication. The objective of this work was to study the participation of the target genes TXNIP, TXN, SLC19A2, SLC19A3 and B2M in the pathogenesis of DN in type 1 DM (T1D) patients. We studied the urinary sediment messenger RNA (mRNA) from patients with T1D (n=55); with focal and segmental glomerulosclerosis (FSGS, a non diabetic nephropathy model, n=12) and from control subjects (n=11) to assess the expression of the target genes and their association with the severity of DN. We also studied the mRNA expression of peripheral lymphomononuclear (PLMN) cells from T1D patients (n=162) and control subjects (n=26) in order to compare with the results obtained in the urinary sediment. Plasmatic concentrations of thiamine were also measured in a subgroup of T1D patients and control subjects. In addition, a lineage of human kidney cells was exposed to high glucose concentrations and to glycated and non-glycated albumin to evaluate if AGEs are implicated in the modulation of expression of the target genes. As a result we found that (1) TXNIP and TXN are upregulated in the urinary sediment of T1D patients with kidney disease and TXNIP is associated with the magnitude of glomerular filtration rate decline; (2) TXNIP and TXN are upregulated in PLMN cells from T1D patients; (3) SLC19A2 is upregulated in the urinary sediment of T1D patients with kidney disease; (4) T1D patients present decreased plasmatic thiamine concentrations compared to control subjects; (5) B2M is upregulated in the urinary sediment of T1D patients with kidney disease and (6) TXNIP and B2M are upregulated in human kidney cells exposed concomitantly to high glucose concentrations and glycated albumin. The results of the present study strongly suggest the participation of the TXN system and of B2M in the pathogenesis of DN

Orientador: Alexandre Leite Rodrigues de Oliveira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T03:01:25Z (GMT). No. of bitstreams: 1 SabhaJunior_MarioJoseJorge_D.pdf: 14971588 bytes, checksum: 25740c7d964d2a5c4eb70c84cb462b08 (MD5) Previous issue date: 2007 / Resumo: o estabelecimento das redes nervosas que compõem o Sistema Nervoso Central (SNC) é um processo imensamente complexo dependente, não somente da formação de novos pontos de comunicação, as sinapses, mas também da eliminação de sinapses supranumerárias ou incorretas durante o desenvolvimento. Recentemente, foi descrito um mecanismo demonstrando que a ausência da expressão do complexo de histocompatibilidade principal (MHC classe I) no SNC, diminui a remoção de conexões sinápticas extranumerárias durante o desenvolvimento e aumenta a retração sináptica no animal adulto. Interessantemente, a transecção do axônio induz uma extensa retração dos terminais pré-sinápticos da superfície do corpo celular e dendritos dos neurônios axotomizados. No presente trabalho, investigamos as alterações sinaptológicas nos motoneurônios alfa da intumescência lombar em três linhagens de camundongos isogênicos (C57BL/6J, A/J e Balb/cJ), após 1 e 3 semanas da transecção do nervo ciático. Nesse sentido, estudamos a cobertura sináptica dos corpos celulares dos motoneurônios após a lesão. Foram utilizadas medulas espinhais de camundongos machos adultos, as quais foram processadas e analisadas para imunohistoquímica (lH) e microscopia eletrônica de transmissão . (MET). Para IH, foram utilizados anticorpos anti-MHC e anti-sinaptofisina conjugados com anticorpos secundários CY-2 ou CY-3 e analisados em microscópio confocal. Os resultados mostraram aumento significativo da expressão de MHC I na linhagem AIJ, comparativamente à Balb/cJ e C57BL/6J, 1 semana após axotomia. Contudo, mostraram níveis similares de expressão desta molécula 3 semanas após axotomia. Adicionalmente, observamos uma diminuição significativa da expressão de sinaptofisina na linhagem AIJ, após 1 semana da transecção do nervo ciático. Após 3 semanas da lesão nervosa, todas as linhagens, apresentaram níveis similares de expressão de sinaptofisina. Os resultados da MET, após 1 semana da transecção do nervo ciático, mostraram menor cobertura sináptica na linhagem A/J, comparada à Balb/cJ e C57BL/6J. Contudo, 3 semanas após a lesão a linhagem C57BL/6J apresentou menor cobertura sináptica, enquanto AIJ e Balb/cJ recuperam suas aferências. Concluímos que a expressão de MHC I influencia o processo de eliminação sináptica e, possivelmente contribui para o potencial regenerativo dos neurônios axotomizados / Abstract: The wiring of the Central Nervous System (CNS) is an immensely complex process, not only dependent on new communication points, the synapses, but also on the elimination of exuberant or inappropriate synapses during development. Earlier studies have shown that the abscence of class I major histocompatibility complex (class I MHC) in the CNS decreases synaptic elimination during CNS development and increases synaptic retraction in adult. Thus, an axon transection has been shown to induce an extensive detachment of presynaptic terminais from perikarya and dendrites ofaxotomized neurons. In the present work, we investigated synaptological changes in alpha motoneurons from lumbar intumescence in three mice isogenic strains (C57/BL6J, AIJ and Balb/cJ), 1 and 3 weeks after sciatic nerve transection. For this purpose we studied ultrastructurally the synaptic covering of the cell soma of sciatic motoneurons after the lesion. Therefore, spinal cords from adult male mice were processed for transmission electron microscopy (TEM) and imunohistochemistry (IH). For IH, anti-MHC I and anti-synaptofisin antibodies were used, conjugated with CY2 or CY3 secondary antibodies and analyzed with a confocal microscope. The results showed a significant increased expression of MHC I in AIJ strain in comparison to Balb/cJ and C57BL/6J, 1 week after axotomy. Nevertheless, the immunoreactivity levels of this molecule 3 weeks after axotomy did not differ among the studied mice strains. Additionally, a conspicuous decrease of synaptofisin expression in A/J mice was observed 1 week after sciatic transection. Similarly to the MHC I immunolabelirlg, 3 weeks after lesion, ali mice strains showed similar levels of synaptofisin expression. The results from TEM 1 week after lesion showed a lower synaptic covering in AIJ mice in comparison to Balb/cJ and C57BL/6J, although 3 weeks after axotomy C57BL/6J displayed a lower synaptic covering, while AIJ and Balb/cJ strains recovered their afferents, We conclude that the levei of MHC I expression influences the synaptic elimination process and possibly contributes to the regenerative potencial of the axotomized neurons / Doutorado / Anatomia / Doutor em Biologia Celular e Estrutural