La conductivité hydraulique foliaire (KF) est une composante majeure du transport d’eau dans toute la plante. Dans les feuilles de noyer, la KF est stimulée à la lumière et est étroitement liée à l’accroissement du taux des transcrits d’aquaporines JrPIP2s. Par ailleurs, la corrélation entre la stimulation de la KF et des transcrits d’aquaporines à la lumière, n’est pas générale et dépend de l’espèce. Ici, nous étudions cette corrélation chez cinq espèces forestières (Juglans regia, Fagus sylvitica, Quercus robur, Salix alba et Populus tremula) différant par leur réponse à la lumière. Nous démontrons seulement chez le noyer (Juglans regia), la contribution des deux familles d’aquaporines PIP1s et PIP2s. Afin de mieux comprendre le rôle des JrPIP1s et JrPIP2 dans la réponse à la lumière, nous avons isolé 8 nouvelles isoformes dans les feuilles de noyer et nous avons étudié leurs profils d’expression sur une cinétique lumière. Toutes les isoformes étudiées sont accumulées à la lumière et réprimées à l’obscurité. De plus, la KF est dépendante de la qualité de lumière. Elle est réduite de 65% en absence de lumière bleue. Cette diminution serait liée à l’inhibition des transcrits d’aquaporines. Afin de caractériser les mécanismes moléculaires précoces impliqués dans la modulation de KF par la lumière, l’approche globale cDNA-AFLP a été menée sur des feuilles de noyer sous différentes conditions d’éclairement. Nous obtenons 12000 transcrits différentiels dérivés (TDFs) générés par les 128 couples d’amorces. Parmi les 187 séquences obtenues, 93 d’entre elles ont une fonction putative. Leur classification fonctionnelle montre que les gènes relatifs à la régulation cellulaire représentent environ 58% des TDFs identifiés. Les feuilles exposées à la lumière, montrent des changements dans les voies de : signalisation calcique, protéolyse, trafic vésiculaire et l’expression de divers facteurs de transcription et protéines de régulation. Pour mieux comprendre le rôle potentiel de la signalisation calcique dans la modulation de la KF par la lumière, nous avons étudié l’effet d’un inhibiteur des canaux calciques [LaCl3] et d’un antagoniste de calmoduline [W7] sur la KF et les transcrits des 10 JrPIPs. Comparées aux feuilles témoins, les inhibiteurs calciques provoquent une réduction de la KF et de la majorité des JrPIPs étudiées à la lumière. Nos résultats confirment l’implication du complexe Ca2+ /calmoduline dans la transduction du signal lumineux responsable de la stimulation de la KF et des transcrits d’aquaporines chez le noyer. / Leaf hydraulic conductance (Kleaf) takes a significant part in plant water relations. In walnut leaves, Kleaf was stimulated by light and tightly related to accumulation of JrPIP2s aquaporin transcripts. However, the light effect on Kleaf value is not systematically related to aquaporin regulation. Here we investigated the relationship between light, Kleaf and transcript levels of aquaporin in five species (Juglans regia, Fagus sylvitica, Quercus robur, Salix alba and Populus tremula) differing by the response of their Kleaf to light. Only for walnut leaves, we showed that light-increased Kleaf value is closely related to higher stimulation of both PIP1s and PIP2s aquaporins. To further investigate the involvement of aquporins (JrPIP1s and JrPIP2) in the light Kleaf modulation, 8 new full length aquaporins have been identified in walnut leaves and their expression pattern was monitored. All the aquaporin tested was turned up to be upregulated under light condition and downregulated under darkness. Moreover, we showed that the Kleaf response to light is quality-dependant, since it was reduced of 65% in the absence of blue light. Interstingly, this Kleaf reduction was correlated with a high downregulation of almost all aquaporins tested. To give an insight into the early molecular events involved in the light-induced Kleaf regulation, a large-scale transcriptomic analysis consisting of the cDNA-AFLP procedure was carried out on walnut leaves, kept at different light conditions. We obtained a total of 12,000 transcript-derived fragments (TDFs) by cDNA-AFLP with 128 primer pairs. Reliable sequences were obtained for 187 of these TDFs, and functions were attributed to 93 TDFs through BLAST searches in GenBank databases. Most of the 93 TDFs corresponded to genes encoding proteins involved in cellular regulation (58%). Leaves exposed to light showed changes in the Ca2+-signaling pathway, the ubiquitin-proteasome pathway, vesicle trafficking process and the expression of multiple transcription factors and protein regulators. To progress in understanding of a potential role for calcium signalling in light-modulated Kleaf, Kleaf values and transcript accumulation of 10 JrPIPs were monitored in leaves perfused with either a blocker of calcium channels [LaCl3] or a CaM antagonist [W7]. Compared to control, these Ca2+ -effectors led to a significant reduction in Kleaf and transcripts accumulation of almost all JrPIPs under light conditions. Our results indicate that Ca2+ /calmodulin complex may transduce the light signal required for stimulation of Kleaf and its correlated aquaporin expression.

An exceptionally important stress response of Pseudomonas putida strains to toxic chemicals is the induction of efflux pumps that extrude solvents, as well as other toxicants, into the surrounding medium. However, the bacterial tolerance mechanisms are still not fully understood, thus in this thesis metabolomic approaches were used to detect and identify metabolites involved in P. putida DOT-T1E tolerance to abiotic stresses, in particular focussing on the role of efflux pumps. To elucidate any metabolome alterations several strains of P. putida, including the wild type DOT-T1E, and the efflux pump knockouts DOT-T1E-PS28 and DOT-T1E-18, were challenged with different levels of propranolol. Fourier-transform infrared (FT-IR) spectroscopy, which provided a rapid, high-throughput metabolic fingerprint of P. putida strains, was used to investigate any phenotypic changes resulting from exposure to propranolol. FT-IR data illustrated phenotypic changes associated with the presence of propranolol within the cell that could be assigned to the bacterial protein components. To complement this phenotypic fingerprinting approach metabolic profiling on the same samples was performed using gas chromatography mass spectrometry (GC-MS) to identify metabolites of interest during growth of bacteria following this toxic perturbation with propranolol. GC-MS revealed significant changes in ornithine levels which can be directly linked to bacterial tolerance mechanisms, and alterations in the levels of several other metabolites which were also modified in response to propranolol exposure. Moreover, the effect of the organic solvent toluene was also investigated using the same approach. Examination of FT-IR data indicated that protein and fatty acids were the most affected components of P. putida strains due to the presence of toluene within the cell. Moreover, application of GC-MS allowed for the identification and quantification of several metabolites which were differentially produced or consumed in the presence of toluene. To investigate the role of efflux pumps in P. putida DOT-T1E, several analytical techniques were employed including Raman spectroscopy, gas and liquid chromatography to identify and quantify the level of propranolol or toluene in P. putida cells. These analyses showed that propranolol and toluene accumulated in the mutant P. putida DOT-T1E-18 (lacking the TtgABC pump) at higher levels in comparison with the levels found in the wild-type DOT-T1E and the mutant DOT-T1E-PS28 (lacking the TtgGHI pump), indicating the key role of efflux pumps in solvent tolerance. Furthermore, the effect of Mg2+ and Ca2+ on the stabilisation of the toluene tolerance of P. putida DOT-T1E strains was examined in order to elucidate whether divalent cations interact with efflux pumps or other resistant mechanisms to improve solvent tolerance. FT-IR analysis suggested that the influence of divalent cations on the stabilisation of the toluene tolerance could be due to the contribution of metal ions towards other tolerance mechanisms such as lipopolysaccharide (LPS) instead of enhancing the activity of efflux pumps. In conclusion, this thesis presents evidence that phenotypic fingerprinting and metabolic profiling approaches in combination with chemometric methods can generate valuable information on phenotypic responses occurring within microbial cultures subjected to abiotic stress.

Chez les mammifères, le glutamate est un neuromédiateur bien connu au niveau du système nerveux central et plus récemment un rôle immunomodulateur lui a été reconnu. Le glutamate est le ligand de récepteurs ionotopiques (iGluRs) qui sont des récepteurs-canaux perméables à divers cations dont le calcium (non-selective cation channels, NSCC). Chez Arabidopsis thaliana, une famille de 20 gènes de iGluRs homologues des iGluRs de mammifères a été identifiée et leur implication dans divers processus biologiques est suggérée. Dans ce travail où nous utilisons des suspensions de cellules de tabac (Nicotiana tabacum var Xanthi), divers arguments suggèrent que ces iGluR sont fonctionnels dans le tabac : influx de calcium et élévation rapide et transitoire de la concentration en calcium cytosolic libre en réponse à l’addition de glutamate, inhibition de ces effets par 4 antagonistes de iGluRs animaux (compétitifs ou non compétitifs), désensibilisation, et pH dépendance des effets. Pour la première fois chez les plantes nous montrons que le glutamate induit la production de NO très vraisemblablement via l’activation de iGluRs. De plus, nous démontrons que ce(s) iGluRs sont impliqués dans le mode d’action, via les flux de calcium, de la cryptogéine une protéine de 10 kDa de Phytophthora cryptogea, éliciteur des réactions de défense chez le tabac. Néanmoins, à ce niveau, les iGluRs ne sont pas impliqués dans la plupart des événements calcium-dépendants induits par la cryptogéine dont l’activation des MAPKs et de canaux anioniques, la production de H2O2 (activation de la NADPH-oxydase) et la réponse hypersensible. En revanche, ils sont tout ou partiellement responsables de la production de NO décrite pour la première fois par le passé en réponse à la cryptogéine. Ces résultats suggèrent que différents types de canaux calciques activés par divers médiateurs, génèrent, via le calcium, des messages spécifiques décodés par des protéines associées à chacun de ces types de canaux et impliquées dans des réponses biologiques différentes. Dans le mode d’action de la cryptogéine, nous démontrons que l’activation des iGluRs est possible grâce à l’exocytose de glutamate dans l’apoplaste, induite par la cryptogéine. Ainsi, ce travail est la première démonstration du rôle de iGluRs potentiels dans la défense chez les plantes et de leur implication dans la production de NO. Nos résultats sont un argument supplémentaire à la conservation des mécanismes de la défense dans le monde vivant et posent le problème du rôle du glutamate dans la signalisation chez les plantes. / Glutamate is recognized as the primary excitatory neurotransmitter in the mammalian central nervous system (CNS) but recent studies have shown that glutamate has an important additional immunomodulator role. Glutamate is the ligand of ionotropic glutamate receptors (iGluRs), which are non-selective cation channels (NSCC), permeable to calcium. In plants, animal iGluR homologs were found that were involved in many developmental processes. Here we demonstrate the involvement of putative iGluRs in calcium signalling in response to cryptogein which is a 10 kDa protein secreted by the oomycete Phytophthora cryptogea and is an elicitor of defence in tobacco. Using transformed tobacco cell suspensions expressing aequorin in the cytosol or in the nucleus, our results have shown that glutamate induces a strong and transient [Ca2+]cyt elevation without [Ca2+]nuc changes. Glutamate-induced [Ca2+]cyt elevation was a result of calcium influx from the extracellular medium and was inhibited by different GluR inhibitors. This data suggest the presence of functional calcium channels of GluRs-type in tobacco. Nevertheless, glutamate does not induce some of the calcium-dependent characteristic events of the defence pathways, which are H2O2 production, MAPK activation and hypersensitive response, but promoted NO production. Further, Ca2+ influx,[Ca2+]cyt elevation and NO production induced by cryptogein were shown to be partially inhibited by the glutamate receptor inhibitors, suggesting that cryptogein treatment could activate a calcium channel of the GluR-type leading to plant defense signalling through NO production. We have also demonstrated that cryptogein induces an efflux of glutamate in the apoplast by the process of exocytosis thus activating the GluRs in tobacco. This is the first demonstration for a potential GluR(s) involvement in plant defense signalling, furthermore by mechanisms that showed homology with glutamate effect on neuronal cells.

Indiana University-Purdue University Indianapolis (IUPUI) / Protein-protein interactions play a crucial role in a wide range of biological processes. Research on the design and synthesis of small molecules to modulate these proteinprotein interactions can lead to new targets and drugs to modulate their function. In Chapter one, we discuss the design and synthesis of small molecules to probe a proteinprotein interaction in a voltage-gated Ca2+ channel. Virtual screening identified a compound (BTT-3) that contained a 3,4-dihydro-3,4’-pyrazole core. This compound had modest biological activity when tested in a fluorescence polarization (FP) assay. The synthetic route to BTT-3 consisted of six steps. In addition, analogs of BTT-3 were made for a structure-activity study to establish the importance of a carboxylate moiety. We also synthesized a biotinylated benzophenone photo-affinity probe and linked it to BTT-3 to identify additional protein targets of the compound. In Chapter two, small-molecule antagonists targeting uPA-uPAR protein-protein interaction are presented. A total of 500 commercially-available compounds were previously identified by virtual screening and tested by a FP assay. Three classes of compounds were found with biological activity. The first class of compounds contains pyrrolidone core structures represented by IPR- 1110, the second class has a novel pyrrolo[3,4-c]pyrazole ring system, represented by xv IPR-1283 and the last series had compounds with a 1,2-disubstituted 1,2- dihydropyrrolo[3,4-b]indol-3(4H)-one core structure, represented by IPR-540. Each of these three compounds were synthesized and assessed by FP and ELISA assays. A binding mode of IPR-1110 with uPA was subsequently proposed. Based on this binding mode, another 61 IPR-1110 derivatives were synthesized by us to illustrate the SAR activity. Analogs of the other two series were also synthesized.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20633号 / 工博第4371号 / 新制||工||1679(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 森 泰生, 教授 浜地 格, 教授 跡見 晴幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24485号 / 医博第4927号 / 新制||医||1063(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 江藤 浩之, 教授 湊谷 謙司, 教授 大鶴 繁 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DGAM

According to the centers for disease control and prevention (CDC) and the world healthorganization (WHO), heart disease and immune related diseases such as diabetes and cancer areamong the leading causes of death around the world. Thus, the regulation of the function ofimmune cell plays a key role in health and disease. Calcium (Ca2+) ions play a critical role inimmune cell activation, function and in a robust immune response. Defects in Ca2+ signalinginfluences the development of cardiac disease, Alzheimer disease, immune cell metabolism,muscle dysfunction, and cancer. Each immune cell is unique in its activation and function,making it relevant to understand how activation of each type of immune cell is regulated. Herewe describe the role of the nBMP2 protein in macrophage activation and function and the role ofthe CD5 co-receptor in helper T cell activation and function.The nuclear bone morphogenetic protein 2 (nBMP2) is the nuclear variant of the bonemorphogenetic protein 2 (BMP2), a growth factor important in heart development, neurogenesis,bone, cartilage and muscle development. To better understand the function of nBMP2, transgenicnBMP2 mutant mice were generated. These mice have a slow muscle relaxation and cognitivedeficit caused in part by abnormal Ca2+ mobilization. Mutant nBMP2 mice also have an impairedsecondary immune response to systemic bacterial challenge. Here we have further characterizedmacrophage activation and function from mutant nBMP2 mice before and after bacterialinfection. We describe how nBMP2 influences the Ca2+ mobilization response and phagocytosisin macrophages, revealing a novel role of the nBMP2 protein in immune cell regulation.CD5 is a surface marker on T cells, thymocytes, and the B1 subset of B cells. CD5 isknown to play an important role during thymic development of T cells. CD5 functions as anegative regulator of T cell receptor (TCR) signaling and fine tunes the TCR signaling response.Here we describe our characterization of CD5 regulation of Ca2+ signaling in naïve helper Tcells. We also outline our findings examining how CD5-induced changes in helper T cellactivation influence other biological processes such as immune cell metabolism, the diversity ofthe gut microbiome, and cognitive function and behavior. Thus, this work elucidates theinfluence of the CD5 co-receptor on the functional outcomes in multiple systems when CD5 isaltered.

AMP-activated protein kinase (AMPK) is known as a pivotal cellular energy sensor, mediating the adaptation to low energy levels by deactivating anabolic processes and activating catabolic processes in order to restore the cellular ATP supply when the cellular AMP/ATP ratio is increased. Besides this well-known role, it has also been shown to exert protective effects under hypoxia. While an insufficient supply with oxygen might easily deplete cellular energy levels, i.e., ATP concentration, manifold other mechanisms have been suggested and are heavily disputed regarding the activation of AMPK under hypoxia independently from cellular AMP concentrations. However, an activation of AMPK preceding energy depletion could induce a timely adaptation reaction preventing more serious damage. A connection between AMPK and the master regulator of hypoxic adaptation via gene transcription, hypoxia-inducible factor (HIF), has also been taken into account, orchestrating their concerted protective action. This review will summarize the current knowledge on mechanisms of AMPK activation under hypoxia and its interrelationship with HIF.

Insects maintain blood (haemolymph) Ca2+ concentrations within a narrow range in order to support the health of internal tissues and organs. The Malpighian (renal) tubules play a primary role in haemolymph Ca2+ homeostasis by sequestering excess Ca2+ within calcified biomineral deposits (Ca-rich granules) often located within type I (principal) tubule cells. Using the classic Ramsay assay, the scanning ion-selective microelectrode technique (SIET), and modifications of these two electrophysiological techniques, this thesis begins to unravel the sites and mechanisms of Ca2+ transport by the Malpighian tubules isolated from eight insects, representing seven orders. A segment-specific pattern of Ca2+ flux was observed along the length of the Malpighian tubules isolated from D. melanogaster, A. aegypti and A. domesticus and was uniform along the length in the remaining species. The majority (≥ 90%) of Ca2+ entering the tubule cells is sequestered within intracellular calcium stores in Ca2+-transporting segments of D. melanogaster and A. domesticus tubules, consistent with the presence of Ca-rich storage granules in these tubule segments. In addition, this thesis provides the first measurements of basolateral Ca2+ flux across single principal and secondary tubule cells of T. ni, where Ca2+ uptake occurs only across principal cells. Perhaps the most important finding of this thesis is that increasing fluid secretion through manipulation of intracellular levels of cAMP or Ca2+ in isolated tubules of A. domesticus had opposite effects on tubule Ca2+ transport. The adenylyl cyclase-cAMP-PKA pathway promotes Ca2+ sequestration whereas both 5-hydroxytryptamine and thapsigargin inhibited sequestration. In contrast, tubules of the remaining species were generally insensitive to cAMP or thapsigargin and v rates of tubule Ca2+ transport were often very low. The presence of Ca-rich granules in the cells of the midgut in several of the species with low rates of tubule Ca2+ transport provide evidence for a putative role of the midgut in haemolymph Ca2+ homeostasis. Taken together, these results suggest that the principal cells of the Malpighian tubules contribute to haemolymph calcium homeostasis through neuroendocrine regulated sequestration of excess Ca2+ during periods of high dietary calcium intake. Sequestration of dietary Ca2+ by the midgut may reduce Ca2+ entry into the haemolymph and therefore Ca2+ sequestration by the Malpighian tubules need not be so rapid. Finally, reversible tubule Ca2+ transport may allow internal reserves of Ca2+ (Ca-rich granules) to be returned to the haemolymph allowing insects to survive prolong periods of Ca2+ deficiency (i.e. overwintering). / Thesis / Doctor of Philosophy (PhD) / This thesis contributes to our understanding of how insects regulate the calcium content of their blood (haemolymph). Using electrophysiological techniques with improved spatial resolution (from millimeters to micrometers) this thesis sought to determine the sites, mechanisms and regulation of Ca2+ transport by insect Malpighian (renal) tubules in order to gain insights into the role of Ca-rich granules (similar to those identified in early stages of human kidney stone formation i.e. nephrolithiasis) within these tissues. Using eight insect species this thesis demonstrates that the Malpighian tubules act as dynamic Ca2+ stores that appear to be under neuroendocrine control: actively taking up Ca2+ through calcium entry channels, where the majority (≥ 90%) of excess haemolymph Ca2+ is sequestered within intracellular stores (Ca-rich granules) during period of excess dietary calcium and passively releasing Ca2+ back to the haemolymph during periods of metamorphosis or calcium deficiency (i.e. overwintering).

L'enzynle HSD3B2 humaine et la protéine STAR de souris encodées par les gènes HSD3B2 et Star, respectivement, sont retrouvées principalement au niveau des gonades et surrénales. L'importance de STAR comme transporteur du cholestérol et de HSD3B2 comme enzyme de la stéroïdogenèse est lnise en évidence par des mutations de ces gènes causant une hyperplasie congénitale des surrénales, un pseudohermaphrodisme mâle et une insuffisance des surrénales. Un rôle pour la famille de récepteurs nucléaires orphelins NUR 77 dans la stéroïdogenèse a été considéré. En effet, NUR77 est présent dans les gonades et surrénales où son expression est fortement et rapidement induite par des horlnones qui activent certains gènes impliqués dans la stéroïdogenèse. De plus, les profils d'expression de Nur77 et des gènes RSD3B2 et Star sont corrélés. Lors de cette thèse, j'ai démontré que les promoteurs HSD3B2 et Star constituent des nouvelles cibles de NUR77. Des éléments de réponse localisés à -130 pb et -95 pb des promoteurs HSD3B2 et Star respectivement, sont essentiels et suffisants pour conférer une réponse dépendante de NUR77, et la mutation de ces élélnents . diminue leurs activités basale et homlono-dépendante dans les cellules stéroïdogéniques. Dans les cellules de Leydig, un réduction de l'expression de Nur77 par siARN réduit l'induction de l'expression de Star par l'AMPc. Également, NUR77 coopère avec des co activateurs de la famille SRC et avec des membres de la famille AP-1 dans la régulation des promoteurs RSD3B2 et Star, respectivement. De plus, le dexaméthasone, un glucocorticoïde synthétique, inhibe l'activation de Star en diminuant le recrutement de NUR77, et non SF-I, à la région proximale du promoteur Star, donnant un argument moléculaire à la suppression causée par le stress de la production de testostérone dans le testicule. J'ai démontré que la voie de signalisation des CaMK est requise pour l'expression de STAR et NUR77 en réponse à l'AMPc dans les cellules de Leydig. Ainsi, CaMKI est spécifiquement exprimé dans les cellules de Leydig. Enfin, je démontre que CaMKI coopère avec NUR 77 et MEF2 pour activer les promoteurs Star et Nur77, respectivement, dans ces cellules. Ainsi, l'identification de NUR 77 comme régulateur important des promoteurs HS1J3B2 et Star et de son mécanisme d'action aident à mieux défénir la spécificité tissulaire et la régulation hormonale de ces gènes dans les cellules de Leydig en plus de soulever un rôle pour CaMKI dans ce processus.