Mental retardation in Down syndrome (DS) has been imputed to the decreased brain volume, which is evident starting from the early phases of development. Recent studies in a widely used mouse model of DS, the Ts65Dn mouse, have shown that neurogenesis is severely impaired during the early phases of brain development, suggesting that this defect may be a major determinant of brain hypotrophy and mental retardation in individuals with DS. Recently, it has been found that in the cerebellum of Ts65Dn mice there is a defective responsiveness to Sonic Hedgehog (Shh), a potent mitogen that controls cell division during brain development, suggesting that failure of Shh signaling may underlie the reduced proliferation potency in DS. Based on these premises, we sought to identify the molecular mechanisms underlying derangement of the Shh pathway in neural precursor cells (NPCs) from Ts65Dn mice. We found that the expression levels of the Shh receptor Patched1 (Ptch1) were increased compared to controls both at the RNA and protein level. Partial silencing of Ptch1 expression in trisomic NPCs restored cell proliferation, indicating that proliferation impairment was due to Ptch1 overexpression. We further found that the overexpression of Ptch1 in trisomic NPCs is related to increased levels of AICD, a transcription-promoting fragment of amyloid precursor protein (APP). Increased AICD binding to the Ptch1 promoter favored its acetylated status, thus enhancing Ptch1 expression. Taken together, these data provide novel evidence that Ptch1 over expression underlies derangement of the Shh pathway in trisomic NPCs, with consequent proliferation impairment. The demonstration that Ptch1 over expression in trisomic NPCs is due to an APP fragment provides a link between this trisomic gene and the defective neuronal production that characterizes the DS brain.

La possibilità di indurre stati ipotermici ed ipometabolici come il torpore o l’ibernazione in animali non ibernanti può avere dei risvolti utili nella pratica medica, in quanto permetterebbe di trarre vantaggio dagli effetti benefici dell’ipotermia senza gli effetti compensatori negativi causati dalla risposta omeostatica dell’organismo. Con questo lavoro vogliamo proporre un nuovo approccio, che coinvolge il blocco farmacologico dell’attività dei neuroni nel bulbo rostroventromediale (RVMM), un nucleo troncoencefalico che si è rivelato essere uno snodo chiave nella regolazione della termogenesi attraverso il controllo dell’attività del tessuto adiposo bruno, della vasomozione cutanea e del cuore. Nel nostro esperimento, sei iniezioni consecutive del agonista GABAA muscimolo nel RVMM, inducono uno stato reversibile di profonda ipotermia (21°C al Nadir) in ratti esposti ad una temperatura ambientale di 15°C. Lo stato ipotermico/ipomentabolico prodotto dall’inibizione dei neuroni del RVMM mostra forti similitudini col torpore naturale, anche per quanto concerne le modificazioni elettroencefalografiche osservate durante e dopo la procedura. Come negli ibernati naturali, nei ratti cui viene inibito il controllo della termogenesi si osserva uno spostamento verso le regioni lente delle spettro di tutte le frequenze dello spettro EEG durante l’ipotermia, ed un forte incremento dello spettro EEG dopo il ritorno alla normotermia, in particolare della banda Delta (0,5-4Hz) durante il sonno NREM. Per concludere, questi risultati dimostrano che l’inibizione farmacologica selettiva di un nucleo troncoencefalico chiave nel controllo della termogenesi è sufficiente per indurre uno stato di psuedo-torpore nel ratto, una specie che non presenta stati di torpore spontaneo. Un approccio di questo tipo può aprire nuove prospettive per l’utilizzo in ambito medico dell’ipotermia. / The possibility to mimic hypomethabolic and hypothermic states like torpor or hibernation in non-hibernating animals may be useful in medical practice since the beneficial effects of deep hypothermia could be obtained without the concomitant elicitation of adverse autonomic compensatory responses. Until now, tentatives of induction of such states have been focused on the inhibition of cellular metabolism at systemic level but worked only in animals already able to enter torpor. Here we show a new approach, that involves the pharmacological blockade of the activity of the neurons within the Rostral Ventromedia Medulla (RVMM), a brainstem area that has been shown to be a key thermogenetic relay that controls the brown adipose tissue, the cutaneous blood vessels and the heart. In our experiment, six consecutive injections, aimed to block the thermogenetic drive by the activation of the GABAA receptors in RVMM neurons, induced a reversible deep hypothermia (21°C at nadir) state in free behaving rats exposed to 15°C ambient temperature. The hypothermic/hypometabolic state produced by prolonged inhibition of RVMM neurons strongly resembles the naturally occurring torpor, even in the EEG changes observed during and after the procedure. Like animals that spontaneously show hibernation or torpor, rats with the thermogentic drive blocked show a left-shift of all the EEG frequencies during the hypothermia, and a strong increase in EEG power spectrum after the return to thermoneutrality, in particular in the EEG Delta band (0.5-4.0 Hz) during NREM sleep. In conclusion, these results show that the selective pharmacological inhibition of a key brainstem area of the cold-defence pathway is sufficient in inducing a topor-like state in the rat, a species that does not enter torpor spontaneously. Such an approach may open new perspectives in the use of deep hypothermia in several medical conditions.

This thesis presents SEELF (Sustainable EEL fishery) Index, a methodology for evaluation of European eel (Anguilla anguilla) for the implementation of an effective Eel Management Plan, as defined by EU Regulation No.1100/2007. SEELF uses internal and external indices, age and blood parameters, and selects suitable specimen for restocking; it is also a reliable tool for eel stock management. In fact, SEELF Index, was developed in two versions: SEELF A, to be used in field operations (catch&release, eel status monitoring) and SEELF B to be used for quality control (food production) and research (eel status monitoring). Health status was evaluated also by biomarker analysis (ChE), and data were compared with age of eel. Age determination was performed with otolith reading and fish scale reading and a calibration between the two methods was possible. The study area was the Comacchio lagoon, a brackish coastal lagoon in Italy, well known as an example of suitable environment for eel fishery, where the capability to use the local natural resources has long been a key factor for a successful fishery management. Comacchio lagoon is proposed as an area where an effective EMP can be performed, in agreement with the main features (management of basins, reduction of mortality due to predators,etc.) highlighted for designation of European Restocking Area (ERA). The ERA is a new concept, proposed as a pillar of a new strategy on eel management and conservation. Furthermore, the features of ERAs can be useful in the framework of European Scale Eel Management Plan (ESEMP), proposed as a European scale implementation of EMP, providing a more effectiveness of conservation measures for eel management.

La malattia da reflusso gastroesofageo (GERD) si divide in due categorie: malattia non erosiva (NERD) ed erosiva (ERD). Questi due fenotipi di GERD mostrano caratteristiche patofisiologiche e cliniche differenti. NERD è la forma più comune. Anche se ERD e NERD sono difficili da distinguere a livello clinico, la forma NERD possiede caratteristiche fisiologiche, patofisiologiche, anatomiche, e istologiche uniche. La replicazione cellulare dello strato basale si pensa sia una delle cause implicate nella resistenza della mucosa e nella difesa strutturale dell’epitelio. Diversi studi hanno dimostrato che la proliferazione cellulare è ridotta nella mucosa esofagea esposta ad insulti acidi e peptici cronici, in pazienti GERD, in più uno studio recente ha dimostrato che il recettore per i cannabinoidi CB1 era implicato nella riparazione delle ferite nella mucosa del colon. Sulla base di questi dati abbiamo valutato la presenza del recettore CB1 in biopsie della mucosa esofagea, di pazienti ERD, NERD e di controlli sani, tramite analisi Western Blot, Immunoistochimica e Real-Time PCR, dimostrando per la prima volta la presenza di questo recettore nell’epitelio dell’esofago e una riduzione dei suoi livelli di espressione nei pazienti ERD, camparati con i NERD e con i controlli sani. Successivamente, per chiarire meglio i meccanismi molecolari che caratterizzano ERD e NERD, abbiamo effettuato un analisi proteomica con la tecnica shotgun, la quale ha evidenziato un patter proteico di 33 proteine differenzialmente espresse in pazienti NERD vs ERD, sette delle quali confermate in wester Blot, e quattro in immunoistochimica. Concludendo i nostri risultati hanno confermato che ERD e NERD sono due entità distinte a livello proteico, e hanno proposto dei candidati biomarker per la diagnosi differenziale di ERD e NERD. / Gastroesophageal reflux disease (GERD) falls into one of two categories: non-erosive reflux disease (NERD) or erosive reflux disease (ERD). The two main phenotypes of GERD show different pathophysiological and clinical characteristics. NERD is the most common phenotypic presentation among GERD. Although separation of ERD and NERD on a clinical level is difficult, there are physiological, pathophysiological, anatomical, and even histological characteristics that are unique to NERD. Cell replication of basal layers is hypothesized to be one of the causes implicated in the resistance of the mucosa and structural epithelial defense. Several studies demonstrated that cell proliferation was reduced in esophageal mucosa exposed to chronic acid-peptic insult, in patients with GERD. In addition, a recent study demonstrated that cannabinoid receptor 1 was implicated in colon mucosa wound healing. Based on these findings, we investigated the presence of CB1 receptors in biopsies of esophageal mucosa, collected from GERD patients and healthy subjects. The biopsies were analyzed by Western Blot, Immunoistochemistry and Real-Time PCR. Our results showed, for the first time, the presence of CB1 receptors in human esophageal epithelium. In addition, we demonstrated that the levels of CB1 mRNA and protein in ERD subjects showed a reduction in comparison with NERD patients. In order to elucidate molecular features that characterize NERD an ERD, a shotgun proteomics approach was assessed. The comparison of the protein patterns between NERD and ERD subjects demonstrated a differentially expression of 33 proteins, seven of them were confirmed by Western Blot analysis, and four of them by immunoistochemistry. In conclusion our results confirmed that NERD and ERD disease could be considered two distinct entities of the same pathology, at protein level. This study proposes an array of candidate biomarkers to discriminate between non-erosive and erosive reflux disease.

I microRNA sono una classe di piccole molecole di RNA non codificante che controllano la stabilità di numerosi RNA messaggeri, perciò sono considerati come “master regulator” dell’espressione genica. Ogni tumore è caratterizzato da un profilo di espressione alterato dei microRNA. Il miR-101 è un oncosoppressore represso nei tessuti tumorali ed è candidato come biomarcatore del cancro colon-rettale. È regolato da numerosi eventi fisiologici e patologici, come angiogenesi e carcinogenesi. Gli eventi molecolari coinvolti nella regolazione dell’espressione del miR-101 sono scarsamente conosciuti, poiché è trascritto da due loci genici non caratterizzati. L’obiettivo di questo lavoro è di caratterizzare i geni del miR-101 ed individuarne i regolatori molecolari coinvolti nella cancerogenesi colon-rettale. / MicroRNAs are a class of small, non-coding RNAs that control the stability of many messenger RNAs and serve as “master regulators” of gene expression. The alterations in the expression of microRNAs is a common feature of cancers. The oncosuppressor miR-101 is hardly expressed in tumor samples and is a candidate biomarker in colorectal cancer. It is regulated under a number of physiological and pathological conditions, including angiogenesis and tumors. Little is known about the molecular factor involved in the regulation of miR-101 expression, because it has 2 unknown genetic loci. The aim of this work is the characterization of miR-101 genes and shed light on its molecular regulators involved in colorectal carcinogenesis.

We usually perform actions in a dynamic environment and changes in the location of a target for an upcoming action require both covert shifts of attention and motor planning update. In this study we tested whether, similarly to oculomotor areas that provide signals for overt and covert attention shifts, covert attention shifts modulate activity in cortical area V6A, which provides a bridge between visual signals and arm-motor control. We performed single cell recordings in monkeys trained to fixate straight-ahead while shifting attention outward to a peripheral cue and inward again to the fixation point. We found that neurons in V6A are influenced by spatial attention demonstrating that visual, motor, and attentional responses can occur in combination in single neurons of V6A. This modulation in an area primarily involved in visuo-motor transformation for reaching suggests that also reach-related regions could directly contribute in the shifts of spatial attention necessary to plan and control goal-directed arm movements. Moreover, to test whether V6A is causally involved in these processes, we have performed a human study using on-line repetitive transcranial magnetic stimulation over the putative human V6A (pV6A) during an attention and a reaching task requiring covert shifts of attention and reaching movements towards cued targets in space. We demonstrate that the pV6A is causally involved in attention reorienting to target detection and that this process interferes with the execution of reaching movements towards unattended targets. The current findings suggest the direct involvement of the action-related dorso-medial visual stream in attentional processes, and a more specific role of V6A in attention reorienting. Therefore, we propose that attention signals are used by the V6A to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly appears at an unattended location.

Down syndrome (DS) is a genetic pathology characterized by brain hypotrophy and severe cognitive disability. Although defective neurogenesis is an important determinant of cognitive impairment, a severe dendritic pathology appears to be an equally important factor. It is well established that serotonin plays a pivotal role both on neurogenesis and dendritic maturation. Since the serotonergic system is profoundly altered in the DS brain, we wondered whether defects in the hippocampal development can be rescued by treatment with fluoxetine, a selective serotonin reuptake inhibitor and a widely used antidepressant drug. A previous study of our group showed that fluoxetine fully restores neurogenesis in the Ts65Dn mouse model of DS and that this effect is accompanied by a recovery of memory functions. The goal of the current study was to establish whether fluoxetine also restores dendritic development and maturation. In mice aged 45 days, treated with fluoxetine in the postnatal period P3-P15, we examined the dendritic arbor of newborn and mature granule cells of the dentate gyrus (DG). The granule cells of trisomic mice had a severely hypotrophic dendritic arbor, fewer spines and a reduced innervation than euploid mice. Treatment with fluoxetine fully restored all these defects. Moreover the impairment of excitatory and inhibitory inputs to CA3 pyramidal neurons was fully normalized in treated trisomic mice, indicating that fluoxetine can rescue functional connectivity between the DG and CA3. The widespread beneficial effects of fluoxetine on the hippocampal formation suggest that early treatment with fluoxetine can be a suitable therapy, possibly usable in humans, to restore the physiology of the hippocampal networks and, hence, memory functions. These findings may open the way for future clinical trials in children and adolescents with DS.

La Leucoencefalopatia Megalencefàlica amb Quists subcorticals (MLC) és un tipus rar de leucodistròfia vacuolitzant de progressió lenta, que presenta com a principals característiques clíniques macrocefàlia acusada durant els primers anys de vida, deteriorament de les funcions motores, epilèpsia i retard mental de grau mig. L’any 2001 es va identificar el primer gen responsable de la malaltia en humans denominat MLC1, tot i que existien pacients de MLC que no presentaven mutacions en MLC1 ni lligació amb el seu locus. Això suggeria que hi havia com a mínim un altre gen involucrat en la malaltia. MLC1 codifica per una proteïna de membrana que porta el mateix nom que s’expressa en cèl•lules glials. La funció de MLC1 és desconeguda però estudis bioquímics van mostrar que mutacions en aquesta proteïna provoquen una reducció dels nivells de proteïna a la membrana i una forta retenció al reticle endoplasmàtic. L’objectiu general d’aquesta Tesi és avançar en la comprensió del possible mecanisme d’acció i la funció de la proteïna MLC1 i així aprofundir en el coneixement de la fisiopatologia de la malaltia. Per realitzar aquest objectiu es va seguir l’aproximació experimental d’identificar i analitzar l’interactoma de MLC1. Per poder validar interaccions entre proteïnes de membrana es va utilitzar el mètode PCA de Split-TEV. Es va observar que el mètode no presentava suficient especificitat i per això, es van realitzar una sèrie de modificacions en la tècnica per obtenir una nova variant de la metodologia amb alta sensibilitat i especificitat. Paral•lelament, es van realitzar estudis de genòmica i proteòmica que van permetre obtenir un llistat de proteïnes candidates a interaccionar amb MLC1. Es van seleccionar les proteïnes més interessants i es va validar la interacció amb MLC1 per coimmunolocalització en cultius primaris d’astròcits de rata i pel mètode de Split-TEV. Mitjançant col•laboracions del grup es va realitzar un estudi genètic dels candidats favorables a interaccionar amb MLC1 i així es va identificar a GlialCAM com a segon gen implicat en MLC. GlialCAM és una proteïna amb una estructura similar a les proteïnes d’adhesió que s’expressa en cèl•lules glials. Estudis del grup van descriure a GlialCAM com a subunitat β de MLC1 i subunitat auxiliar del canal de clorur ClC-2, ja que és capaç d’interaccionar i dirigir aquestes proteïnes a les zones de contacte entre cèl•lules i provocar canvis funcional en el canal. El descobriment de GlialCAM va fer focalitzar els objectius de la Tesi en l’estudi d’aquesta proteïna. Es van realitzar estudis d’estructura-funció de GlialCAM mitjançant la utilització de proteïnes quimèriques i la generació de delecions. Aquests estudis van identificar el domini extracel•lular de GlialCAM com a domini responsable de la interacció en cis i en trans de la proteïna. El domini citoplasmàtic es va relacionar amb la localització de la proteïna a les unions cel•lulars i finalment, es van identificar els primers aminoàcids del domini transmembrana de GlialCAM com els responsables dels canvis funcionals de ClC-2. També es van generar i caracteritzar els models knock-down tant de MLC1 com de GlialCAM en cultius primaris d’astròcits de rata. L’estudi d’aquests models i de complementacions dels models amb l’expressió de proteïnes humanes o diferents mutacions de MLC1 i GlialCAM, van permetre descriure GlialCAM com a xaperona necessària per la sortida del reticle endoplasmàtic i la localització de MLC1 a les unions astrocitàries. Estudis funcionals van permetre relacionar MLC1 amb l’activitat VRAC i el control del volum cel•lular i es va identificar com a proteïna responsable de l’aparició de vacuoles astrocitàries en els pacients de MLC. Finalment, es va observar que les mutacions en MLC1 eren capaces d’activar VRAC per se i causaven el defecte en trobar-se retingudes. La coexpressió de GlialCAM amb aquestes mutacions de MLC1 provocava una recuperació de la localització de MLC1 i una disminució del fenotip vacuolitzant astrocitari. Aquest resultat podria ser el principi d’una possible teràpia pels pacients amb MLC basada en l’augment de l’expressió en superfície de les variants mutants de MLC1. / Megalencephalic Leukoencephalopathy with subcortical Cysts (MLC) is a rare type of leukodystrophy characterized by early-onset macrocephaly and delayed-onset neurological deterioration. In 2001 MLC1 was identified as the first gen involved in 75% of human MLC patients. These results suggested that there was at least another gen involved in MLC pathogenesis. MLC1 is a membrane protein with an unknown function that is expressed in glial cells. Biochemical studies showed a decrease of surface expression and retention in the endoplasmatic reticulum in MLC1 mutations. The principal aim of this study is to advance in the knowledge of the MLC pathogenesis and the MLC1 function. To accomplish the study, the group performed the identification and analysis of the MLC1 interactome as experimental approach. The Split-TEV method was used to identify interactions between membrane proteins. However this method showed a low specificity and some modifications were developed to obtain a new variant of Split-TEV method with high sensibility and specificity. At the same time, using genomic and proteomic studies we identified a list of interaction proteins that were candidates to belong to the MLC1 interactome. The interaction candidates were validated by coimmunolocalization in astrocyte primary cultures and by Split-TEV method. A genetic study was performed with the most favourable candidates and GlialCAM was identified as the second gene involved in MLC disease. GlialCAM is a membrane protein with a similar structure to the adhesion proteins that is expressed in glial cells. Biochemical studies identified GlialCAM as a β subunit of MLC1 and as an auxiliary subunit of the ClC-2 chloride channel. The aim of this study was focused then to advance in the knowledge of the GlialCAM protein. We conducted structure-function studies using chimaeric proteins and GlialCAM deletions. These studies identified the extracellular domain of GlialCAM as the responsible domain of the cis and trans protein interaction. The citoplasmatic domain was related to the correct location of the protein in the cell-cell junctions, and the first aminoacids of the transmembrane domain were responsible for the functional changes in ClC-2. Finally, we developed and characterized MLC1 and GlialCAM knock-down models in astrocyte primary cultures. The study of these models and its complementation with MLC1 and GlialCAM human variants or/and MLC1 and GlialCAM mutant variants, identified a new function of GlialCAM as a chaperone needed for MLC1 endoplasmatic reticulum exit and correct localization in astrocytic junctions. Functional studies implicated MLC1 with the VRAC activation and cell volume regulation. Moreover the coexpression of MLC1 mutant variants with GlialCAM caused an increase of surface expression of MLC1 mutant variants and an activation of VRAC function. These results may be the beginning of a possible pharmacological strategy to obtain a therapy for MLC patients.

Les cèl·lules de leucèmia limfocítica crònica (LLC) en sang perifèrica presenten una resistència anòmala a la inducció d'apoptosi, i reben senyals del microentorn cel·lular que afavoreixen la seva supervivència. En un gran percentatge de malalts no s'aconsegueix controlar la malaltia amb les teràpies convencionals, i en molts altres apareixen recaigudes i resistències al tractament, sobretot degudes a alteracions en la via de p53. A més, la majoria de tractaments no són selectius per les cèl·lules tumorals, provocant problemes d'immunosupressió. Per tant, és necessari identificar nous agents amb toxicitat selectiva per les cèl·lules B malignes, que utilitzin mecanismes d'acció diferents als coneguts i que sobrepassin la via de p53.En aquesta tesi doctoral ens vam plantejar estudiar una de les vies de supervivència més alterades en càncer, i que ja havia demostrat que jugava un paper en la supervivència de les cèl·lules de LLC. Així, l'objectiu d'aquesta tesi ha estat caracteritzar la xarxa de PKC/PI3K/Akt, i els efectes de la seva inhibició en les cèl·lules de LLC.En primer lloc, hem comprovat que existeixen dues vies de senyalització convergents en les cèl·lules de LLC. La primera, dependent de PI3K, present de manera basal en les cèl·lules de LLC i activada per factors de supervivència com la IL-4 i el SDF-1alfa; i una segona, dependent de PKC, també present de manera basal en les cèl·lules de LLC i activada per PMA. En aquesta via, PKCbeta juga un paper important en la fosforilació i activació d'Akt.Hem comprovat com la inhibició de la via, amb inhibidors generals de PKC (Bis I), de PI3K, generals (LY294002 i wortmanina) o selectius de les isoformes de classe I, o d'Akt (Akti-1/2 i A-443654), indueix apoptosi en les cèl·lules de LLC. Aquesta inducció de mort cel·lular es dóna inclús en presència de senyals de supervivència (IL-4, SDF-1alfa, PMA) i en pacients amb delecions 17p o mutacions en p53. Això confirma que aquesta via juga un paper clau en la supervivència de les cèl·lules leucèmiques de LLC.A més, les cèl·lules B de LLC són més sensibles a la inhibició d'aquesta via que les cèl·lules T normals, i en alguns casos, inclús que les cèl·lules B normals (com en el cas del tractament amb Akt1-1/2). Aquesta "addició oncogènica" de les cèl·lules tumorals a la via de PI3K/Akt, ja s'ha descrit en altres càncers, on s'ha demostrat que les teràpies contra PI3K/Akt indueixen més mort cel·lular en les cèl·lules amb més activitat de la via, com són les cèl·lules tumorals. Així, una vegada més, comprovem que la via d'Akt és d'especial importància per aquestes cèl·lules leucèmiques, i que la seva inhibició és d'especial interès per aconseguir noves teràpies més selectives, que evitin els efectes secundaris immunosupressors.En conjunt, els resultats obtinguts en aquesta tesi doctoral aporten nous coneixements sobre les vies de supervivència i d'inducció d'apoptosi de les cèl·lules de LLC, i demostren que la inhibició de la via PKC/PI3K/Akt és una prometedora via d'intervenció terapèutica pel tractament de la LLC. / CLL cells from peripheral blood receive signals from the microenvironment that supports their survival and present an anomalous resistance to the induction of apoptosis. One of the survival pathways that have been described to contribute to CLL cells survival is PKC/PI3K/Akt pathway. A high number of patients are resistant to the current therapies, and most of the treatments are not selective for tumoral cells. Thus, new compounds with a different mechanism of action are needed. The main goal of this thesis has been to characterize the PKC/PI3K/Akt pathway, and the effects of its inhibition in CLL cells.First, we proved that CLL cells have two convergent signal transduction pathways to phosphorylate and activate Akt. The first pathway is PI3K-dependent and corresponds to the classical PI3K-Akt pathway described in most models. The second pathway depends on PKCβ, is independent of PI3K, and contributes to the basal-constitutive Akt activity present in B-CLL cells. By using general and specific PKC, PI3K and Akt inhibitors we confirmed that the inhibition of this pathway induces apoptosis in CLL cells. This apoptosis is observed even in the presence of survival pathways and in patients with alterations in p53. We found that B cells from CLL samples were more sensitive to the inhibition of this pathway than T cells from CLL samples, and B or T cells from healthy donors. Most of the current drugs induce apoptosis equally in both B and T cells, leading to immunosuppression. Thus, the differential effect of these inhibitors in B and T lymphocytes is of interest. In conclusion, the results presented in this thesis contribute to increase the knowledge on the survival pathways and the regulation of apoptosis in CLL cells, and suggest that inhibition of PKC/PI3K/Akt might be a new therapeutic option for CLL therapy.

La proteïna SAP18 va ser identificada inicialment en cèl·lules de mamífer com a membre del complex que forma el repressor transcripcional mSin3 i les desacetilases d'histones, proposant així una possible funció d'aquesta proteïna en la regulació de l'estructura de la cromatina. A partir d'aquest treball inicial han aparegut varis articles que descriuen, a diversos organismes models, l'associació de SAP18 amb altres proteïnes proposant-li funcions tan diverses com el control de l'expressió gènica o la regulació de l'apoptosi i del desenvolupament. Tot i aquests treballs, la funció concreta i l'expressió de SAP18 estan poc caracteritzades, i precisament aquests han estat els objectius que ens hem plantejat en aquesta tesis: caracteritzar l'expressió i identificar processos funcionals on participi la proteïna dSAP18 a Drosophila melanogaster. / SAP18 protein was initially identified in mammal cells as a component of the Sin3-HDAC transcriptional repressor complex, suggesting a possible role of this protein in the regulation of chromatin structure. After this first work there have appeared several articles that they describe, in several model organisms the association of SAP18 with other proteins proposing that so many different functions as the control of gene expression or the regulation of apoptosis or the development. Despite this initial work, the specific function and pattern of expression of SAP18 protein are poorly characterized, and these are precisely the goals that we have raised in this thesis: to characterize the expression pattern and to identify functional process where the SAP18 protein is involved in Drosophila melanogaster.