ABSTRACT The morphological premalignant changes in prostate epithelium such as high grade prostatic intraepithelial neoplasia (HGPIN) precede invasive prostate cancer (PC) by several decades. The overall aim of this project was to identify patterns of gene expression in HGPIN and early PC which increase our understanding of the early biology of PC and identify genes and pathways that correlate with an aggressive phenotype. A comprehensive tissue cohort of premalignant prostate lesions was collected in a tissue microarray (TMA) platform that was utilised for high-throughput validation of target genes. Using this unique resource, the expression of the tumour suppressor gene PTEN was assessed using immunohistochemistry in an initial candidate gene approach based on mouse models implicating PTEN in carcinogenesis. No significant difference in expression of PTEN was detected in premalignant and benign epithelium. A transcript profiling approach was undertaken by integrating laser capture microdissection, linear RNA amplification and oligonucleotide microarrays to perform a screen of matched patient samples of normal, HGPIN and PC cells. The expression patterns of two genes encoding secreted proteins, neuropeptide Y (NPY) and macrophage inhibitory cytokine (MIC-1) were validated using immunohistochemistry on TMAs representing the progression model of early PC. Increased expression of these proteins in PC was confirmed to occur early in the disease process and altered expression of NPY and MIC-1 was associated with worse clinical outcome. Further analysis of global gene expression patterns using a structured network knowledge base identified a notable aberration in the expression of extracellular matrix and extracellular matrix associated proteins in HGPIN and provided novel evidence for the role of this class of molecules in the development of PC. In summary, contrary to current dogma based on work in animal models, altered PTEN expression is unlikely to represent an important event in the development of malignancy in the human prostate. In contrast, the expression patterns and prognostic value of NPY and MIC-1 in HGPIN support their further evaluation as biomarkers for the development and progression of PC. The aberrant expression of genes and networks of genes detected in HGPIN will assist in further identification of biological pathways which may be targeted in therapeutic strategies against the development and progression of PC.

ABSTRACT The morphological premalignant changes in prostate epithelium such as high grade prostatic intraepithelial neoplasia (HGPIN) precede invasive prostate cancer (PC) by several decades. The overall aim of this project was to identify patterns of gene expression in HGPIN and early PC which increase our understanding of the early biology of PC and identify genes and pathways that correlate with an aggressive phenotype. A comprehensive tissue cohort of premalignant prostate lesions was collected in a tissue microarray (TMA) platform that was utilised for high-throughput validation of target genes. Using this unique resource, the expression of the tumour suppressor gene PTEN was assessed using immunohistochemistry in an initial candidate gene approach based on mouse models implicating PTEN in carcinogenesis. No significant difference in expression of PTEN was detected in premalignant and benign epithelium. A transcript profiling approach was undertaken by integrating laser capture microdissection, linear RNA amplification and oligonucleotide microarrays to perform a screen of matched patient samples of normal, HGPIN and PC cells. The expression patterns of two genes encoding secreted proteins, neuropeptide Y (NPY) and macrophage inhibitory cytokine (MIC-1) were validated using immunohistochemistry on TMAs representing the progression model of early PC. Increased expression of these proteins in PC was confirmed to occur early in the disease process and altered expression of NPY and MIC-1 was associated with worse clinical outcome. Further analysis of global gene expression patterns using a structured network knowledge base identified a notable aberration in the expression of extracellular matrix and extracellular matrix associated proteins in HGPIN and provided novel evidence for the role of this class of molecules in the development of PC. In summary, contrary to current dogma based on work in animal models, altered PTEN expression is unlikely to represent an important event in the development of malignancy in the human prostate. In contrast, the expression patterns and prognostic value of NPY and MIC-1 in HGPIN support their further evaluation as biomarkers for the development and progression of PC. The aberrant expression of genes and networks of genes detected in HGPIN will assist in further identification of biological pathways which may be targeted in therapeutic strategies against the development and progression of PC.

ABSTRACT The morphological premalignant changes in prostate epithelium such as high grade prostatic intraepithelial neoplasia (HGPIN) precede invasive prostate cancer (PC) by several decades. The overall aim of this project was to identify patterns of gene expression in HGPIN and early PC which increase our understanding of the early biology of PC and identify genes and pathways that correlate with an aggressive phenotype. A comprehensive tissue cohort of premalignant prostate lesions was collected in a tissue microarray (TMA) platform that was utilised for high-throughput validation of target genes. Using this unique resource, the expression of the tumour suppressor gene PTEN was assessed using immunohistochemistry in an initial candidate gene approach based on mouse models implicating PTEN in carcinogenesis. No significant difference in expression of PTEN was detected in premalignant and benign epithelium. A transcript profiling approach was undertaken by integrating laser capture microdissection, linear RNA amplification and oligonucleotide microarrays to perform a screen of matched patient samples of normal, HGPIN and PC cells. The expression patterns of two genes encoding secreted proteins, neuropeptide Y (NPY) and macrophage inhibitory cytokine (MIC-1) were validated using immunohistochemistry on TMAs representing the progression model of early PC. Increased expression of these proteins in PC was confirmed to occur early in the disease process and altered expression of NPY and MIC-1 was associated with worse clinical outcome. Further analysis of global gene expression patterns using a structured network knowledge base identified a notable aberration in the expression of extracellular matrix and extracellular matrix associated proteins in HGPIN and provided novel evidence for the role of this class of molecules in the development of PC. In summary, contrary to current dogma based on work in animal models, altered PTEN expression is unlikely to represent an important event in the development of malignancy in the human prostate. In contrast, the expression patterns and prognostic value of NPY and MIC-1 in HGPIN support their further evaluation as biomarkers for the development and progression of PC. The aberrant expression of genes and networks of genes detected in HGPIN will assist in further identification of biological pathways which may be targeted in therapeutic strategies against the development and progression of PC.

Pancreatic islet beta cell failure causes type 2 diabetes in humans. To identify transcriptomic changes in type 2 diabetic islets, the Innovative Medicines Initiative for Diabetes: Improving beta-cell function and identification of diagnostic biomarkers for treatment monitoring in Diabetes (IMIDIA) consortium (www.imidia.org) established a comprehensive, unique multicentre biobank of human islets and pancreas tissues from organ donors and metabolically phenotyped pancreatectomised patients (PPP).

L’apport de fer est essentiel pour la plupart des organismes vivants, incluant la majorité des bactéries pathogènes. Cependant, le fer libre est toxique : il est lié à des protéines de stockage et de transport (e.g. ferritine, hémoprotéines…) et voit son homéostasie finement régulée. Afin d’extraire le fer de ces protéines, les bactéries utilisent divers systèmes tels que des protéines de surface ou encore des sidérophores. Bacillus cereus est une bactérie Gram-positive sporulante, pathogène opportuniste chez l’homme, 2ème cause en France de toxi-infection alimentaire collective. Chez B. cereus, la protéine de surface IlsA et le sidérophore bacillibactine (BB) sont impliqués dans l’acquisition du fer de la ferritine exogène et elles sont importantes pour l’infection de l’insecte modèle Galleria mellonella. Mes travaux présentaient deux parties : tout d’abord, l’étude de l’import du complexe BB-Fe3+ dans la cellule par FeuA, protéine de liaison de ce complexe à la surface de la bactérie, souligne le rôle central du couple BB-FeuA. La délétion des gènes codants pour ces deux molécules limite l’acquisition par B. cereus du fer de la ferritine, de l’hème, de l’hémoglobine et du fer inorganique in vitro. En revanche, elle présente un phénotype de virulence in vivo comparable à la souche de référence dans le cas d’injection intra-hémocœlique de larves de G. mellonella. Ce résultat surprenant suggère un probable rétrocontrôle sur l’expression de facteurs de virulence lorsque B. cereus ne produit ni BB ni FeuA, et se trouve par conséquent fortement carencé en fer. Le second volet de mes travaux s’intéresse à l’expression des gènes liés à l’homéostasie du fer in vivo, au cours de l’infection de l’intestin de larves de G. mellonella axéniques. Nous avons choisi une approche de type microgénomique, en prélevant les échantillons par microdissection laser, sur de façon à prélever de petits échantillons dans une zone définie, puis en analysant l’expression de quelques gènes ciblés par RT-qPCR et ddPCR à 3h et 16h post ingestion. Nos résultats montrent que : i) la colonisation intestinale de G. mellonella est impactée lorsque B. cereus est dépourvu du couple BB-FeuA ; ii) ilsA est exprimé lors de l’infection intestinale ; iii) les gènes ciblés impliqués dans l’homéostasie du fer sont activés dès le début de l’infection, suggérant un rôle dans l’adaptation et la pathogénicité ; iv) une faible modulation de l’expression est observée entre les deux temps. Ces travaux ouvrent de nouvelles connaissances fondamentales sur l’homéostasie du fer et des perspectives quant à l’utilisation de nouvelles techniques pour l’étude in situ des interactions hôte-pathogène. / Iron acquisition is essential for most living organisms, including many pathogenic bacteria. However, free iron is toxic: it is bound into storage or transport proteins (e.g. ferritin, hemoproteins…) and iron homeostasis is tightly regulated. To scavenge iron from these sources, bacteria possess several systems to acquire the bound iron, by surface proteins or siderophores. Bacillus cereus is a sporeforming Gram-positive bacterium, opportunistic human pathogen, 2nd cause of food-borne disease in France. It has been demonstrated that the B. cereus surface protein IlsA and the siderophore bacillibactin (BB) are involved in iron acquisition from ferritin and that these two molecules are important for infection of the insect model G. mellonella. My thesis project focused on two parts: first the study of the BB-Fe3+ complex import into the cell by the siderophore binding protein FeuA highlights the central role of both BB and FeuA. The deletion of the genes encoding for these two molecules limits iron acquisition by B. cereus from ferritin, heme, hemoglobin and inorganic iron in vitro. On the other hand, the virulence phenotype during intra-haemocelic infection of G. mellonella is similar to the Wild-type strain. These results suggest a possible feedback on the expression of virulence factor genes when B. cereus is unable to synthetize both BB and FeuA, and therefore are under high stress. The second part of my work focused on the expression of genes involved in iron homeostasis in vivo, during gut infection of germ-free larvae of G. mellonella. We chose to perform a microgenomic approach, using laser-capture microdissection to get small samples in targeted areas, and then analysing the expression of chosen genes by RT-qPCR and ddPCR at two time points post ingestion The results show that : i) the colonisation of G. mellonella gut is impacted when B. cereus is deprived of both BB and FeuA ; ii) ilsA is expressed during gut infection ; iii) iron homeostasis is involved in adaptation and pathogenicity from the early step of infection of the insect gut ; iv) only weak gene expression modulation occured between the two timepoints This work gives new fundamental knowledge about B. cereus iron homeostasis, and highlights the use of new techniques regarding the in situ study of host-pathogen interactions.

Obwohl B-Zellen in der Pathogenese der Rheumatoide Arthritis (RA) eine wichtige Rolle spielen, ist über ihre Aktivierung und Differenzierung im Synovialgewebe (SG) nicht viel bekannt. Ein Merkmal von RA ist das Auftreten von Autoantikörpern (auto-AK). Trotz dessen sind bisher kaum Daten über den Einfluss des SG auf die auto-AK-Produktion und die Frequenz autoreaktiver synovialer B-Zellen bekannt. Diese Arbeit beschäftigt sich mit der Charakterisierung der synovialen B-Zell-Antwort und der Spezifität synovialer B-Lymphozyten. Dazu wurden B- und Plasmazellen (PC) aus dem Synovialgewebe von RA-Patienten mittels Mikrodissektion und Durchflusszytometrie isoliert und ihr Immunglobulin(Ig)-Repertoire bestimmt. Die Analyse der VH-Gene zeigte, dass sowohl naive als auch Gedächtnis-B-Zellen in das SG einwandern können. Ein Vergleich der VDJ-Rearrangements aus B-Zellen und PC belegte, dass hauptsächlich Gedächtnis-B-Zellen Antigen-abhängig aktiviert werden, klonal expandieren und zu PC differenzieren. Dabei können aktivierte B-Zellen ihre Ig-Klasse wechseln. Im Gegensatz dazu wurden nur rudimentäre Anzeichen somatischer Hypermutation nachgewiesen. Um die Spezifität synovialer B-Lymphozyten zu ermitteln, wurden rekombinante AK aus synovialen B-Zellen und PC generiert. Der Polyreaktivitätstest zeigte, dass naive B-Zellen aus dem SG einen hohen Anteil polyreaktiver Zellen besitzen. Im Gegensatz dazu ist die Frequenz von autoreaktiven Gedächtnis-B-Zellen und PC gegenüber naiven B-Zellen erhöht. Daneben konnten auch spezifische AK gegen bakterielle Antigene (insbesondere gegen Parodontitis-auslösende Bakterien) und gegen das Auto-Ag MCV identifiziert werden. Eine Affinitätsmessung des MCV-spezifischen Auto-AK zeigte, dass im SG sezernierte Auto-AK eine sehr hohe Affinität erreichen können. Die hier gewonnenen Daten verdeutlichen, dass B-Lymphozyten entscheidend an der Aufrechterhaltung oder gar Entstehung von RA beteiligt sind / Although B cells have an important impact on the pathogenesis of Rheumatoid arthritis (RA) still surprisingly little is known about their activation and differentiation within the inflamed synovial tissue (ST). A hallmark of RA is the presence of auto-antibodies (auto-Ab). However, still little is known about the frequency of self reactive synovial lymphocytes and it is unclear to which extent the inflamed ST contributes to auto-Ab production. These thesis deals with the characterization of the synovial B cell response and the specificity of synovial B lymphocytes. B and plasma cells (PC) from RA patients were isolated either by Laser Capture Microdissection or by FACS and their immunoglobulin(Ig)-repertoire was determined. The analysis of the VH-genes revealed that both naïve and memory B cells can immigrate the ST. A comparison of VDJ-rearrangements of B cells and PC showed that in ST without ectopic germinal centres mainly memory B cells become activated, expand clonally and differentiate into PC. During this process B cells can switch their Ig-class but do only hypermutate slightly. To determine the specificity of synovial B lymphocytes, recombinant Ab from synovial B cells and PC were generated. The polyreactivity assay showed that particularly naïve B cells were polyreactive. In contrast, the frequency of autoreactive memory B cells and PC was much higher than that of naïve B cells. In addition, Ab specific for bacterial antigens (especially for periodontal bacterias) and for the autoantigen MCV were identified. The affinity measurement of the MCV-specific autoantibody revealed that auto-Ab secreted in the ST can exhibit very high affinities. The data presented here show that B cells seem to play an important role in the maintenance and possibly the development of RA.

The subplate layer of the cerebral cortex is comprised of a heterogeneous population of cells and contains some of the earliest-generated neurons. Subplate plays a fundamental role in cortical development. In the embryonic brain, subplate cells contribute to the guidance and areal targeting of corticofugal and thalamic axons. At later stages, these cells are involved in the maturation and plasticity of the cortical circuitry and the establishment of functional modules. In my thesis, I aimed to further characterize the embryonic murine subplate by establishing a gene expression profile of this population at embryonic day 15.5 (E15.5) using laser capture microdissection combined with microarrays. I found over 250 transcripts with presumed higher expression in the subplate at E15.5. Using quantitative RT-PCR, in situ hybridization and immunohistochemistry, I have confirmed specific expression in the E15.5 subplate for 13 selected genes which have not been previously associated with this compartment. In the reeler mutant, the expression pattern of a majority of these genes was shifted in accordance with the altered position of subplate cells. These genes belong to several functional groups and likely contribute to the maturation and electrophysiological properties of subplate cells and to axonal growth and guidance. The roles of two selected genes - cadherin 10 (Cdh10) and Unc5 homologue c (Unc5c) - were explored in more detail. Preliminary results suggest an involvement of Cdh10 in subplate layer organization while Unc5c could mediate the waiting period of subplate corticothalamic axons in the internal capsule. Finally, I compared the expression of a selection of subplate-specific genes (subplate markers) between mouse and rat and found some surprising species differences. Confirmed subplate markers were used to monitor subplate injury in a rat model of preterm hypoxiaischemia and it appeared that deep cortical layers including subplate showed an increased vulnerability over upper layers. Further characterization of subplate-specific genes will allow us to broaden our understanding of molecular mechanisms underlying subplate properties and functions in normal and pathological development.

A Esclerose Lateral Amiotrófica (ELA) é a doença neurodegenerativa do neurônio motor que acomete indivíduos adultos e promove a perda progressiva das funções motoras. A evolução é rápida (2 a 5 anos) e culmina na morte por complicações e falência dos músculos respiratórios. Descrições recentes sugerem a contribuição de tipos celulares não neuronais, particularmente o astrócito e a microglia, para a morte do neurônio motor. O camundongo transgênico SOD1G93A, que carrega a SOD1 humana mutada, foi utilizado neste trabalho. Estudos comportamentais apontaram alterações motoras importantes no animal transgênico a partir de 90 dias de vida e permitiram selecionar, então, as idades pré-sintomáticas de 40 dias e 80 dias para os estudos moleculares. A análise da expressão gênica nos animais transgênicos e selvagens destas duas idades foi realizada por microarray utilizando-se a plataforma que contém o genoma completo do camundongo e detectou 492 e 1105 transcritos diferencialmente expressos nos animais de 40 e 80 dias, respectivamente. Estes resultados foram validados por PCR quantitativa (qPCR). As análises bioinformáticas dos resultados identificaram 17 e 11 vias moleculares super-representadas nas idades de 40 dias e 80 dias, respectivamente. Destas, as vias endocitose, sinapse glutamatérgica, proteólise mediada por ubiquitina, via de sinalização de quimiocina, fosforilação oxidativa, processamento e apresentação de antígeno e junção oclusiva foram comuns a ambas as idades. Ainda, as vias sinapse glutamatérgica e fagossomo foram sugeridas como potencialmente mais importantes em animais transgênicos de 40 dias e 80 dias, respectivamente. Transcritos específicos foram analisados em amostras enriquecidas de células (astrócito, microglia e neurônio motor) microdissecadas a laser do corno anterior da medula espinal dos animais. Os transcritos Cxcr4, Slc1a2 e Ube2i foram avaliados por qPCR nas amostras enriquecidas de astrócitos dos animais de 40 dias, enquanto que Cxcr4 e Slc17a6 foram avaliados nas amostras de neurônios motores dos animais desta idade. Cxcr4 apresentou expressão diminuída nos astrócitos transgênicos e aumentada nos neurônios destes animais. Slc1a2, Ube2i e Slc17a6 estavam aumentados nos tipos celulares estudados nos animais transgênicos. Tap2 e Tuba1a foram avaliados nas amostras enriquecidas de microglias dos animais de 80 dias e mostraram-se aumentados nas amostras dos transgênicos. Finalmente, Akt1 apresentou expressão diminuída nos neurônios motores microdissecados dos animais transgênicos em comparação aos selvagens. Os resultados sugerem que alterações na sinalização glutamatérgica podem exercer papel essencial em fases pré-sintomáticas mais precoces da doença (40 dias), enquanto que em fases pré-clínicas mais próximas ao aparecimento dos sintomas (80 dias), as respostas mais importantes parecem estar relacionadas à neuroimmunomodulação. Dessa forma, este trabalho aponta para novas perspectivas para o estudo da ELA / Amyotrophic Lateral Sclerosis (ALS) is an adult onset motor neuron neurodegenerative disease that leads to the progressive loss of muscular functions. It is a fast progression disorder (2 to 5 years) culminating in death by respiratory failure. Recent findings suggest that non neuronal cell types, especially astrocytes and microglia, might contribute to the neuronal death. The transgenic mouse SOD1G93A, carring human mutant SOD1, was used in this study. Behavioral studies pointed to the onset of the clinical symptoms occurring at 90 days in the animal model, thus, allowing the selection of the pre-symptomatic ages of 40 and 80 days to the molecular studies. Gene expression analysis of transgenic mice and their non-transgenic littermates at those ages was performed by using a microarray platform containing the whole mouse genome and has detected 492 and 1105 differentially expressed genes at 40 days and 80 days old mice, respectively. These results were validated by quantitative PCR (qPCR). Bioinformatic analysis of the results identified 17 and 11 over-represented molecular pathways at 40 days and 80 days, respectively. Of these, endocytosis, glutamatergic synapse, ubiquitin-mediated proteolysis, chemokine signaling pathway, oxidative phosphorylation, antigen processing and presentation and also tight junction were common to both ages. Furthermore, glutamatergic synapse and fagosome were suggested as potentially more important at 40 and 80 days, respectively. Specific transcripts were analyzed on enriched samples of cells (astrocytes, microglia and motor neuron) obtained by laser microdissection from the ventral horn of mouse spinal cord. The transcripts Cxcr4, Slc1a2 and Ube2i were evaluated by qPCR in enriched samples of astrocytes of the 40 days old mice, and Cxcr4 and Slc17a6 were analyzed in motor neuron samples at this age. Cxcr4 has been found decreased in astrocytes from transgenic mice and increased in the motor neurons of these animals. Slc1a2, Ube2i and Slc17a6 have increased in the cell type in which they were evaluated in the transgenic mice. Tap2 and Tuba1a were evaluated at microglia enriched samples of 80 days old mice and were found to be increased. Finally, Akt1 has decreased in enriched samples of motor neurons from 80 days old mice. The results suggest that glutamatergic signaling might play essential role in early stages of the disease (40 days), while in phases closer to the appearance of the symptoms (80 days), the neuroimmunomodulation takes place. Thus, this study points to new perspectives for ALS study

A Esclerose Lateral Amiotrófica (ELA) é a doença neurodegenerativa do neurônio motor que acomete indivíduos adultos e promove a perda progressiva das funções motoras. A evolução é rápida (2 a 5 anos) e culmina na morte por complicações e falência dos músculos respiratórios. Descrições recentes sugerem a contribuição de tipos celulares não neuronais, particularmente o astrócito e a microglia, para a morte do neurônio motor. O camundongo transgênico SOD1G93A, que carrega a SOD1 humana mutada, foi utilizado neste trabalho. Estudos comportamentais apontaram alterações motoras importantes no animal transgênico a partir de 90 dias de vida e permitiram selecionar, então, as idades pré-sintomáticas de 40 dias e 80 dias para os estudos moleculares. A análise da expressão gênica nos animais transgênicos e selvagens destas duas idades foi realizada por microarray utilizando-se a plataforma que contém o genoma completo do camundongo e detectou 492 e 1105 transcritos diferencialmente expressos nos animais de 40 e 80 dias, respectivamente. Estes resultados foram validados por PCR quantitativa (qPCR). As análises bioinformáticas dos resultados identificaram 17 e 11 vias moleculares super-representadas nas idades de 40 dias e 80 dias, respectivamente. Destas, as vias endocitose, sinapse glutamatérgica, proteólise mediada por ubiquitina, via de sinalização de quimiocina, fosforilação oxidativa, processamento e apresentação de antígeno e junção oclusiva foram comuns a ambas as idades. Ainda, as vias sinapse glutamatérgica e fagossomo foram sugeridas como potencialmente mais importantes em animais transgênicos de 40 dias e 80 dias, respectivamente. Transcritos específicos foram analisados em amostras enriquecidas de células (astrócito, microglia e neurônio motor) microdissecadas a laser do corno anterior da medula espinal dos animais. Os transcritos Cxcr4, Slc1a2 e Ube2i foram avaliados por qPCR nas amostras enriquecidas de astrócitos dos animais de 40 dias, enquanto que Cxcr4 e Slc17a6 foram avaliados nas amostras de neurônios motores dos animais desta idade. Cxcr4 apresentou expressão diminuída nos astrócitos transgênicos e aumentada nos neurônios destes animais. Slc1a2, Ube2i e Slc17a6 estavam aumentados nos tipos celulares estudados nos animais transgênicos. Tap2 e Tuba1a foram avaliados nas amostras enriquecidas de microglias dos animais de 80 dias e mostraram-se aumentados nas amostras dos transgênicos. Finalmente, Akt1 apresentou expressão diminuída nos neurônios motores microdissecados dos animais transgênicos em comparação aos selvagens. Os resultados sugerem que alterações na sinalização glutamatérgica podem exercer papel essencial em fases pré-sintomáticas mais precoces da doença (40 dias), enquanto que em fases pré-clínicas mais próximas ao aparecimento dos sintomas (80 dias), as respostas mais importantes parecem estar relacionadas à neuroimmunomodulação. Dessa forma, este trabalho aponta para novas perspectivas para o estudo da ELA / Amyotrophic Lateral Sclerosis (ALS) is an adult onset motor neuron neurodegenerative disease that leads to the progressive loss of muscular functions. It is a fast progression disorder (2 to 5 years) culminating in death by respiratory failure. Recent findings suggest that non neuronal cell types, especially astrocytes and microglia, might contribute to the neuronal death. The transgenic mouse SOD1G93A, carring human mutant SOD1, was used in this study. Behavioral studies pointed to the onset of the clinical symptoms occurring at 90 days in the animal model, thus, allowing the selection of the pre-symptomatic ages of 40 and 80 days to the molecular studies. Gene expression analysis of transgenic mice and their non-transgenic littermates at those ages was performed by using a microarray platform containing the whole mouse genome and has detected 492 and 1105 differentially expressed genes at 40 days and 80 days old mice, respectively. These results were validated by quantitative PCR (qPCR). Bioinformatic analysis of the results identified 17 and 11 over-represented molecular pathways at 40 days and 80 days, respectively. Of these, endocytosis, glutamatergic synapse, ubiquitin-mediated proteolysis, chemokine signaling pathway, oxidative phosphorylation, antigen processing and presentation and also tight junction were common to both ages. Furthermore, glutamatergic synapse and fagosome were suggested as potentially more important at 40 and 80 days, respectively. Specific transcripts were analyzed on enriched samples of cells (astrocytes, microglia and motor neuron) obtained by laser microdissection from the ventral horn of mouse spinal cord. The transcripts Cxcr4, Slc1a2 and Ube2i were evaluated by qPCR in enriched samples of astrocytes of the 40 days old mice, and Cxcr4 and Slc17a6 were analyzed in motor neuron samples at this age. Cxcr4 has been found decreased in astrocytes from transgenic mice and increased in the motor neurons of these animals. Slc1a2, Ube2i and Slc17a6 have increased in the cell type in which they were evaluated in the transgenic mice. Tap2 and Tuba1a were evaluated at microglia enriched samples of 80 days old mice and were found to be increased. Finally, Akt1 has decreased in enriched samples of motor neurons from 80 days old mice. The results suggest that glutamatergic signaling might play essential role in early stages of the disease (40 days), while in phases closer to the appearance of the symptoms (80 days), the neuroimmunomodulation takes place. Thus, this study points to new perspectives for ALS study

No description available.