O acúmulo de lipídeos associado à obesidade, resistência à insulina (RI) e diabetes mellitus tipo 2 (DM2) pode levar ao desenvolvimento de danos renais, e diversos mecanismos podem estar envolvidos neste processo, dentre os quais: 1) redução na atividade da proteína ativada por AMP (AMPK); 2) hiperativação do sistema renina angiotensina (SRA) e consequente aumento na produção de angiotensina II (Ang II). O treinamento físico aeróbio (TFA) promove melhora metabólica significativa, no entanto, pouco se sabe sobre os mecanismos celulares induzidos pelo TFA contra o desenvolvimento de danos renais associados com doenças metabólicas. Sendo assim, o objetivo deste estudo foi avaliar o potencial do TFA para a prevenção de danos renais induzidos por dieta de cafeteria, e a participação do SRA e da proteína AMPK nessa resposta. Para isso, camundongos machos adultos C57BL6/J foram separados em grupos (n=13/grupo) sedentários (SED) alimentados com dieta normocalórica (NO) ou de cafeteria (CAF) (SED-NO e SED-CAF, respectivamente) e treinados (TF) alimentados com dieta NO ou CAF (TF-NO e TF-CAF, respectivamente). O TFA foi realizado a 60% da capacidade máxima, simultaneamente com as dietas durante 8 semanas. A dieta de cafeteria causou maior adiposidade, intolerância à glicose e RI no grupo SED-CAF, enquanto o TFA preveniu esses prejuízos no grupo TF-CAF. Os animais SED-CAF apresentaram 88% de aumento no ritmo de filtração glomerular (RFG), maior deposição lipídica renal e redução do espaço de Bowman comparado ao SED-NO, as quais foram prevenidas no grupo TF-CAF. Não houve alteração no conteúdo de colágeno IV e fibronectina, entretanto o TNF-alfa aumentou em ambos os grupos alimentados com dieta de cafeteria. Houve aumento de 27% da expressão proteica da p-AMPK no grupo TF-CAF, sem diferenças na expressão de t-ACC, p-ACC, PGC1-alfa e SIRT-1. A expressão gênica do SREBP-1 não diferiu entre os grupos, porém a expressão do SREBP-2 aumentou nos grupos SED-CAF e TF-CAF comparado aos grupos SED-NO e TF-NO. No soro, apenas a atividade da ECA2 aumentou nos grupos TF-NO e TF-CAF comparados aos sedentários. No rim, a atividade da ECA aumentou 46% no grupo SED-CAF comparado ao SED-NO, e o TFA foi capaz de prevenir esse aumento. No entanto, a Ang II renal aumentou nos grupos SED-CAF, TF-NO e TF-CAF comparados ao grupo SED-NO. Não houve diferença nos componentes do SRA ECA2/Ang 1-7/Mas renal. Em conclusão, o TFA preveniu os danos renais causados pela dieta de cafeteria, tais como acúmulo de lipídeos nos rins, aumento do RFG e redução do espaço de Bowman, e essa resposta está associada, pelo menos em parte, com a maior ativação da AMPK independente da contribuição do SRA / Lipid accumulation observed in the obesity, insulin resistance (IR) and Diabetes Mellitus type 2 (DM2) may lead to the development of renal damage, and several mechanisms may be involved in this process, such as: 1) reduction in the AMP-activated protein (AMPK) activity; 2) hyperactivation of the renin angiotensin system (RAS) and consequent increase in the production of Angiotensin II (Ang II). Aerobic exercise training (AET) promotes significant metabolic improvement, however, little is known about the cellular mechanisms induced by AET against the development of kidney damage associated with metabolic diseases. Thus, the present study aimed to evaluate the potential of AET to prevent kidney damage induced by cafeteria diet, and the participation of RAS and AMPK protein in this response. Adult male C57BL6/J mice were separated into sedentary (SED) groups fed a normocaloric (NO) or cafeteria (CAF) (SED-NO and SED-CAF, respectively) and trained (TF) fed a NO or CAF diet (TF-NO and TF-CAF, respectively). The AET was performed at 60% of the maximum capacity simultaneously with the diets during 8 weeks. The cafeteria diet induced adiposity increase, glucose intolerance and IR, while AET prevented these changes. Animals SED-CAF increased 88% of glomerular filtration rate (GFR), increased renal lipid deposition and reduced Bowman\'s space compared to SED-NO, which were prevented by AET in the TF-CAF group. There was no change in the collagen IV and fibronectin, however TNF-alpha increased in both cafeteria diet fed groups. There was a 27% increase in the protein p-AMPK expression in the TF-CAF group, with no changes in t-ACC, p-ACC, PGC1-alpha and SIRT-1 expression. The SREBP-1 gene expression did not change among groups, but SREBP-2 gene expression increased in the SED-CAF and TF-CAF groups compared to the SED-NO and TF-NO groups. In the serum, only the activity of ACE 2 increased in TF-NO and TF-CAF groups compared to sedentary groups. In the kidney, ACE activity increased 46% in the SED-CAF group compared to SED-NO, nevertheless the AET was able to prevent this increase. Renal Ang II concentration increased in SED-CAF, TF-NO and TF-CAF groups compared to the SED-NO. No differences were observed in the components of renal RAS ACE2/Ang 1-7/Mas. In conclusion, AET prevented the renal damage caused by cafeteria diet, such as lipid accumulation, increased GFR and reduced Bowman space, and these responses are associated, at least in part, with greater activation of the AMPK protein independent of the RAS contribution

INTRODUÇÃO: O melanoma primário da cavidade oral é uma neoplasia agressiva, rara e originada a partir da proliferação de melanócitos malignos da mucosa. Ele representa aproximadamente de 0,2 a 8% de todos os melanomas. Estudos recentes apontam algumas vias moleculares tem sido encontradas por estarem envolvidas na patogenia dos melanomas. Dentre essas vias destaca-se a via proliferativa da MAPK (mitogen activated protein kinase), esta cascata de sinalização está envolvida no controle do crescimento celular, proliferação e migração, e tem sido relacionada com um papel importante no desenvolvimento e progressão do melanoma cutâneo. OBJETIVOS: Analisar a expressão proteica e mutação pontual dos componentes da via MAPK e correlacionar com os dados clínicos-histológicos. MATERIAL E MÉTODOS: Através da imunoistoquímica avaliar a expressão proteica dos anticorpos RAS; BRAF; MEK1; MEK2; ERK1 e ERK2 em 35 casos de melanomas orais organizados em matriz (TMA: Tissue Microarray) e através de pirosequenciamento avaliar a mutação pontual dos genes BRAF; NRAS; KRAS em 14 casos de melanomas orais. RESULTADOS: Idade dos pacientes entre 9 e 91 anos, sem predileção por sexo, 75% caucasianos, 71,42% acometeram o palato, 80% com aspecto histológico grau III. A análise da expressão proteica foi: RAS (28,57%); BRAF (82,85%); MEK1 (0%); MEK2 (51,43%); ERK1 (20%)e ERK2 (74,28%). Na análise molecular observamos mutações para BRAF (9/14 casos) e NRAS (2/14 casos). CONCLUSÃO: Todos os aspectos da via MAPK necessita de outras elucidações em melanomas de áreas foto-protegidas e melanomas de mucosa e comparando diferentes populações. Entretanto, os resultados deste presente estudo apontam importante alterações na cascata RAS-RAF-MEK-ERK e estes são indicadores de prognóstico ruim em melanomas primários da mucosa oral, independente da exposição solar / BACKGROUND: Primary melanoma of the oral cavity is an aggressive and rare neoplasm and originated from the proliferation of malignant melanocytes of the mucosa. It represents approximately 0.2 to 8% of all melanomas. Recent studies indicate some molecular pathways have been found to be involved in the pathogenesis of melanomas. Among these means there is a proliferative MAPK pathway (\"mitogen activated protein kinase\"), this signaling pathway is involved in controlling cell growth, proliferation and migration, and it has been associated with a role in the development and progression of melanoma skin. OBJECTIVES: To analyze protein expression and mutation of components of the MAPK pathway and to correlate with the clinical, histological data. MATERIALS AND METHODS: Using immunohistochemistry to evaluate the protein expression of RAS, BRAF, MEK1, MEK2, ERK1 and ERK2 antibodies in 35 cases of oral melanomas organized array (TMA: Tissue Microarray) and using pyrosequencing to assess the mutation of the BRAF, NRAS, KRAS in 14 cases of oral melanomas. RESULTS: Age of patients between 9 and 91 years, regardless of gender, 75% Caucasian, 71.42% in palate, 80% with histologic grade III. Analysis of protein expression was: RAS (28.57%); BRAF (82.85%); MEK1 (0%), MEK2 (51.43%); ERK1 (20%) and ERK2 (74.28%). Molecular analysis we found BRAF mutations (9/14 cases) and NRAS (2/14 cases). CONCLUSION: All aspects of the MAPK pathway requires further elucidation in melanomas of photo-protected areas and mucosal melanomas and comparing different populations. However, the results of this study indicate important changes in the cascade RAS-RAF-MEK-ERK and these are indicators of poor prognosis in primary melanomas of the oral mucosa, regardless of sun exposure

O acúmulo de lipídeos associado à obesidade, resistência à insulina (RI) e diabetes mellitus tipo 2 (DM2) pode levar ao desenvolvimento de danos renais, e diversos mecanismos podem estar envolvidos neste processo, dentre os quais: 1) redução na atividade da proteína ativada por AMP (AMPK); 2) hiperativação do sistema renina angiotensina (SRA) e consequente aumento na produção de angiotensina II (Ang II). O treinamento físico aeróbio (TFA) promove melhora metabólica significativa, no entanto, pouco se sabe sobre os mecanismos celulares induzidos pelo TFA contra o desenvolvimento de danos renais associados com doenças metabólicas. Sendo assim, o objetivo deste estudo foi avaliar o potencial do TFA para a prevenção de danos renais induzidos por dieta de cafeteria, e a participação do SRA e da proteína AMPK nessa resposta. Para isso, camundongos machos adultos C57BL6/J foram separados em grupos (n=13/grupo) sedentários (SED) alimentados com dieta normocalórica (NO) ou de cafeteria (CAF) (SED-NO e SED-CAF, respectivamente) e treinados (TF) alimentados com dieta NO ou CAF (TF-NO e TF-CAF, respectivamente). O TFA foi realizado a 60% da capacidade máxima, simultaneamente com as dietas durante 8 semanas. A dieta de cafeteria causou maior adiposidade, intolerância à glicose e RI no grupo SED-CAF, enquanto o TFA preveniu esses prejuízos no grupo TF-CAF. Os animais SED-CAF apresentaram 88% de aumento no ritmo de filtração glomerular (RFG), maior deposição lipídica renal e redução do espaço de Bowman comparado ao SED-NO, as quais foram prevenidas no grupo TF-CAF. Não houve alteração no conteúdo de colágeno IV e fibronectina, entretanto o TNF-alfa aumentou em ambos os grupos alimentados com dieta de cafeteria. Houve aumento de 27% da expressão proteica da p-AMPK no grupo TF-CAF, sem diferenças na expressão de t-ACC, p-ACC, PGC1-alfa e SIRT-1. A expressão gênica do SREBP-1 não diferiu entre os grupos, porém a expressão do SREBP-2 aumentou nos grupos SED-CAF e TF-CAF comparado aos grupos SED-NO e TF-NO. No soro, apenas a atividade da ECA2 aumentou nos grupos TF-NO e TF-CAF comparados aos sedentários. No rim, a atividade da ECA aumentou 46% no grupo SED-CAF comparado ao SED-NO, e o TFA foi capaz de prevenir esse aumento. No entanto, a Ang II renal aumentou nos grupos SED-CAF, TF-NO e TF-CAF comparados ao grupo SED-NO. Não houve diferença nos componentes do SRA ECA2/Ang 1-7/Mas renal. Em conclusão, o TFA preveniu os danos renais causados pela dieta de cafeteria, tais como acúmulo de lipídeos nos rins, aumento do RFG e redução do espaço de Bowman, e essa resposta está associada, pelo menos em parte, com a maior ativação da AMPK independente da contribuição do SRA / Lipid accumulation observed in the obesity, insulin resistance (IR) and Diabetes Mellitus type 2 (DM2) may lead to the development of renal damage, and several mechanisms may be involved in this process, such as: 1) reduction in the AMP-activated protein (AMPK) activity; 2) hyperactivation of the renin angiotensin system (RAS) and consequent increase in the production of Angiotensin II (Ang II). Aerobic exercise training (AET) promotes significant metabolic improvement, however, little is known about the cellular mechanisms induced by AET against the development of kidney damage associated with metabolic diseases. Thus, the present study aimed to evaluate the potential of AET to prevent kidney damage induced by cafeteria diet, and the participation of RAS and AMPK protein in this response. Adult male C57BL6/J mice were separated into sedentary (SED) groups fed a normocaloric (NO) or cafeteria (CAF) (SED-NO and SED-CAF, respectively) and trained (TF) fed a NO or CAF diet (TF-NO and TF-CAF, respectively). The AET was performed at 60% of the maximum capacity simultaneously with the diets during 8 weeks. The cafeteria diet induced adiposity increase, glucose intolerance and IR, while AET prevented these changes. Animals SED-CAF increased 88% of glomerular filtration rate (GFR), increased renal lipid deposition and reduced Bowman\'s space compared to SED-NO, which were prevented by AET in the TF-CAF group. There was no change in the collagen IV and fibronectin, however TNF-alpha increased in both cafeteria diet fed groups. There was a 27% increase in the protein p-AMPK expression in the TF-CAF group, with no changes in t-ACC, p-ACC, PGC1-alpha and SIRT-1 expression. The SREBP-1 gene expression did not change among groups, but SREBP-2 gene expression increased in the SED-CAF and TF-CAF groups compared to the SED-NO and TF-NO groups. In the serum, only the activity of ACE 2 increased in TF-NO and TF-CAF groups compared to sedentary groups. In the kidney, ACE activity increased 46% in the SED-CAF group compared to SED-NO, nevertheless the AET was able to prevent this increase. Renal Ang II concentration increased in SED-CAF, TF-NO and TF-CAF groups compared to the SED-NO. No differences were observed in the components of renal RAS ACE2/Ang 1-7/Mas. In conclusion, AET prevented the renal damage caused by cafeteria diet, such as lipid accumulation, increased GFR and reduced Bowman space, and these responses are associated, at least in part, with greater activation of the AMPK protein independent of the RAS contribution

The mammalian Na+/H+ exchanger isoform 1 (NHE1) is a ubiquitously expressed membrane protein that regulates intracellular pH. In the myocardium, NHE1 has been implicated in ischemia/reperfusion (I/R) and cardiac hypertrophy (CH). Hormonal, autocrine and paracrine stimuli, acidosis, cardiotoxic metabolites released during I/R and CH increases NHE1 protein expression and activity. The involvement of NHE1 in CH and I/R has been further supported with the use of NHE1 inhibitors, which have been beneficial in the prevention/regression of several models of CH and I/R injury. Despite the fact that elevation of NHE1 expression and activity have been demonstrated in several models of heart disease, it was unclear whether elevation of NHE1 protein expression was sufficient to induce a specific cardiac pathology, or whether activation of the protein was required. To understand the direct role of NHE1 in CH and I/R, an in vivo and in vitro gain-of-function model, expressing varying levels and activities of NHE1 were examined. In vivo, our N-line mice expressed wild type NHE1 and our K-line mice expressed constitutively active NHE1. In vitro, neonatal rat ventricular cardiomyocytes were infected with the IRM adenovirus containing wild type NHE1 or the K-IRM adenovirus containing active NHE1. We demonstrated that expression of constitutively active NHE1 promotes CH to a much greater degree than expression of wild type NHE1 alone, both in vivo and in vitro. This NHE1-dependent hypertrophic response occurred independent of signaling pathways involved in CH including, mitogen activated protein kinases, p90 ribosomal S6 kinase, calcineurin and glycogen synthase kinase. The NHE1-dependent hypertrophic effect also occurred independent of gender. In addition, the expression of active NHE1 increased the susceptibility of intact mice to neurohormonal stimulation and progressed the hypertrophic response. When these hearts expressing active NHE1 were subjected to I/R using the ex vivo working heart perfusion model, fatty acid (FA) oxidation and glycolysis rates increased, thus generating greater ATP production rates. This was associated with cardioprotective effects in the myocardium, as well as a more energetically efficient myocardium. Expression of the endoplasmic reticulum (ER) stress response proteins, calreticulin and PDI were also shown to be increased relative to controls, and may contribute to the cardioprotection observed. We demonstrate that active NHE1 induces cardioprotection and alters cardiac metabolism in working hearts subjected to I/R. Overall, our results suggest that expression of active NHE1 has a double edged sword effect, on one side it induces CH while on the other side, it protects the heart against I/R injury.

No description available.

No description available.

Thesis (Ph. D.)--University of Virginia, 2008. / Title from title page. Includes bibliographical references. Also available online through Digital Dissertations.

La protéine kinase activée par AMP (AMPK) est un senseur ubiquitaire du statut énergétique de la cellule eucaryote. Elle est exprimée sous la forme d'un complexe hétérotrimèrique comprenant les sous unités catalytique (α) et régulatrices (β et γ). Ce large complexe protéique (130kDa), fonctionne comme un hub central de la signalisation cellulaire, régulateur du métabolisme énergétique et au-delà. La (dé)régulation de l'AMPK est impliquée dans de nombreuses pathologies et l'AMPK apparait comme une cible de choix pour développer de nouveaux médicaments contre le diabète de type 2. Une fois activée, l'AMPK va restaurer l'homéostasie énergétique en diminuant le métabolisme demandeur d'énergie (anabolisme) et en stimulant le métabolisme produisant le l'énergie (catabolisme). In vivo, l'AMPK est activée par des mécanismes multiples et complexes permettant la fine régulation de son activité lors de différentes situations de stress métaboliques. Premièrement, l'activité de l'AMPK est modulée de manière systémique par phosphorylation et déphosphorylation de la sous unité α (par des kinases et phosphatases en amont respectivement). De plus, l'attachement d'AMP et d'ADP à la sous unité γ augmente la phosphorylation de l'AMPK. Deuxièmement, l'AMPK est activée de manière allostérique par l'AMP qui se lie à sous unité γ lors de chutes du ratio ATP/AMP. Tous ces mécanismes requièrent une communication entre les sous unités α et γ, mais un modèle consensus complet de l'activation de l'AMPK est toujours manquant. Se basant sur différentes études structurales, d'autres et nous-mêmes avons proposé un changement de conformation induit par AMP au sein de l'hétérotrimère AMPK. Afin de mieux élucider ce mécanisme, nous avons tiré profit de ces changements conformationels pour imaginer et créer un hétérotrimère d'AMPK permettant de suivre directement et en temps réel l'état de conformation de l'AMPK par FRET. Une limite importante lors du développement de complexes multiprotéiques est l'augmentation exponentielle de la quantité de travail liée à la modification et la combinaison de nombreux gènes hétérologues lors du remaniement de ces complexes protéiques et de leurs productions. Nous avons utilisé la technologie ACEMBL, qui exploite des techniques de recombinaisons homologues, pour faciliter la révision rapide et itérative de la production et de l'analyse fonctionnelle, après ingénierie, de complexes multi protéiques. Le senseur fluorescent génétiquement codé ainsi crée, et nommé AMPfret, a la propriété de rapporter les changements de conformation induits par les nucléotides ayant lieu au sein de l'AMPK. De plus, les changements de signal FRET corrèlent avec l'activation allostérique de l'AMPK. Le senseur répond à de faible concentrations en AMP (micromolaire) et a démontré la capacité exclusive qu'a l'ATP, et non l'ATP-Mg, à concurrencer l'AMP. De plus, son utilisation a permis une meilleure compréhension du rôle des sites CBS lors de l'activation allostérique. AMPfret peut aussi être considérer comme un outil de choix pour le criblage de molécules ciblant l'AMPK, et pour le monitoring de l'état énergétique intracellulaire. / AMP-activated protein kinase (AMPK) is a ubiquitous sensor of cellular energy and nutrient status in eukaryotic cells. It is expressed as heterotrimeric complexes comprising catalytic (α) and regulatory (β and γ) subunits. This large protein complex (130kDa), conserved from yeast to plants and mammals, functions as a central signaling hub and master regulator of energy metabolism and beyond. (Dys)regulation of AMPK signaling has been implicated in various pathologies. In particular, AMPK emerged as a suitable target to develop novel drugs for type II diabetes. Once activated AMPK will attempt to restore the energy homeostasis by down-regulating energy demanding pathways (anabolism) and up-regulating the energy producing ones (catabolism). AMPK is activated in vivo by multiple, complex mechanisms allowing fine tuning of AMPK activity in different situations of metabolic stress. First, AMPK activity is systemically modulated via activating phosphorylation at the α-subunit (by upstream kinases) and inactivating dephosphorylation (by upstream phosphatases). In addition, AMP and ADP binding to the γ-subunit increase AMPK phosphorylation. Second, AMPK is allosterically activated by AMP binding to the γ-subunit when the ATP/AMP ratio is falling. All these mechanisms require close communication between the γ- and α subunits, but a complete consensus model for AMPK activation is still lacking. We and others have proposed an AMP-induced conformational switch within the full-length heterotrimeric AMPK complex based on different, complementary structural studies. To further elucidate this mechanism, we have profited from these structural rearrangements to imagine and engineer an AMPK complex that allows a direct, real-time readout of the AMPK conformational state by fluorescence resonance energy transfer (FRET). A definite bottleneck in engineering multiprotein complexes is the exponential increase in work-load if several heterologous genes need to be altered, engineered and combined for revised protein complex production experiments. We used the ACEMBL technology which harnesses site-specific and homologous recombination techniques in tandem to facilitate rapid, iterative revision of multi-protein complex expressions after engineering and functional analysis of multiprotein complex. The resulting genetically encoded fluorescent biosensor, named AMPfret, can report conformational changes within the AMPK heterotrimer induced by nucleotide binding and the monitored FRET correlates with AMPK allosteric activation. The sensor responds to low micromolar concentrations of AMP, shows the exclusive ability of ATP, but not Mg-ATP, to compete with AMP, and allows insight into the role of CBS domains for allosteric AMPK activation. It may also be a tool of choice for AMPK targeted drug screening, and reporting the intracellular energy state.

The c-Jun NH2-terminal kinase (JNK) group of kinases include ten members that are created by alternative splicing of transcripts derived from Jnk1, Jnk2 and Jnk3 genes. The JNK1 and JNK2 protein kinases are ubiquitously expressed while JNK3 is expressed in a limited number of tissues. The JNK signaling pathway is implicated in multiple physiological processes including cell transformation. There is growing evidence that JNK signaling is involved in oncogenesis. Nevertheless, the role that JNK plays in malignant transformation is still unclear. The aim of this thesis is to examine the role of JNK in malignant transformation. For this purpose, I used the Bcr/Abl oncogene as a transforming agent. Bcr/Abl is a leukemogenic oncogene that is created by reciprocal translocation between chromosome 9 and 22. The translocation breakpoint is variable and several different Bcr/Abl isoforms have been identified such as Bcr/AblP185 and Bcr/AblP210, whose expression is associated with different types of leukemia. Bcr/Abl activates the JNK signaling pathway in hematopoietic cells and increases AP-1 transcription activity. Furthermore, dominant negative approaches demonstrate that inhibition of c-Jun or JNK prevents Bcr/ Abl-induced cell transformation in vitro. These data implicate the JNK signaling pathway in Bcr/Abl transformation although the role that JNK might have in this process is unclear. Thus, I examined the importance of JNK signaling in Bcr/Abl-induced lymphoid or myeloid transformation. For this purpose I compared Bcr/AblP185- and Bcr/AblP210- induced transformation of wild-type and JNK1-deficient cells using three approaches: in vitro, in vivo and ex vivo. The results obtained with the in vitro approach suggest that both Bcr/AblP185 and Bcr/AblP210 require JNK activity to induce lymphoid transformation. While JNK1-deficiency inhibits Bcr/AblP210 oncogenic potential in lymphoid cells both in vitro and in vivo, pharmacological inhibition of JNK activity (JNK1 and/or JNK2) blocked Bcr/AblP185 induced malignant proliferation in vitro. The differential requirement for JNK observed in the two Bcr/Abl isoforms can be ascribed to the presence in Bcr/AblP210 of the Dbl domain which can activate the JNK pathway in vitro. In the case of Bcr/AblP210, JNK1 is critical for the survival of the ex vivo derived transformed lymphoblasts upon growth factor removal. This result correlates with the fact that mice reconstituted with Bcr/AblP210 transformed Jnk1-l- bone marrow showed normal malignant lymphoid expansion in the bone marrow yet they had reduced numbers of lymphoblast in the bloodstream and lacked peripheral organ infiltration. Thus JNK1 is essential for the survival of the transformed lymphoblast outside the bone marrow microenvironment in Bcr/AblP210induced lymphoid leukemia. Interestingly, while JNK1 is essential for lymphoid transformation, it is dispensable for the proliferation of transformed myeloblasts. Taken together these results indicate that the JNK signaling pathway plays an essential role in the survival of Bcr/AblP210 lymphoblasts and that JNK-deficiency decreases the leukomogenic potential of Bcr/AblP210 in vivo. Thus, cell survival mediated by JNK may contribute to the pathogenesis of proliferative diseases.

The insulin/IGF-1 signaling pathway plays a pivotal role in life span regulation in diverse organisms. In Caenorhabditis elegans, a PI 3-kinase signaling cascade downstream of DAF-2, an ortholog of the mammalian insulin and insulin-like growth factor-1 (IGF-1) receptor, negatively regulates DAF-16/forkhead transcription factor. DAF-16 then regulates a wide variety of genes involved in longevity, stress response, metabolism and development. DAF-16 also receives signals from other pathways regulating life span and development. However, the precise mechanism by which DAF-16 directs multiple functions is poorly understood. First, in Chapter II, we demonstrate that JNK is a novel positive regulator of DAF-16 in both life span regulation and stress resistance. Our genetic analysis suggests that the JNK pathway acts in parallel with the insulin-like signaling pathway to regulate life span and both pathways converge onto DAF-16. We also show that JNK-1 directly interacts with and phosphorylates DAF-16. Moreover, in response to heat stress, JNK-1 promotes the translocation of DAF-16 into thc nucleus. Our findings define a novel interaction between the stress response pathway (JNK) and the master regulator of life span (DAF-16), and provide a mechanism by which JNK regulates longevity and stress resistance. Next, in Chapter III, we focus on the downstream targets of DAF-16. Here, we used a modified chromatin immunoprecipitation (ChIP) method to identify direct target promoters of DAF-16. We cloned 103 target sequences containing consensus DAF-16 binding sites and randomly selected 33 targets for further analysis. The expression of majority of these genes is regulated in a DAF-16-dependent manner. Moreover, inactivation of more than 50% of these genes significantly altered DAF-16-dependent functions such as longevity, fat storage and dauer diapause. Our results show that the ChIP-based cloning strategy leads to greater enrichment of DAF-16 target genes, compared to previous studies using DNA micro array or bioinformatics. We also demonstrate that DAF-16 is recruited to multiple promoters to coordinate regulation of its downstream target genes. In summary, we identified the JNK signaling pathway as a novel input into DAF-16 to adapt animals to the environmental stresses. We also revealed a large number of novel outputs of DAF-16. Taken together, these studies provide insight into the complex regulation by DAF-16 to control diverse biological functions and eventually broaden our understanding of aging.