Μαθηματική μοντελοποίηση και προσομοιώση της διεργασίας της αεροποίησης πλάσματος για τη διαχείρηση αποβλήτων με ταυτόχρονη ανάκτηση ενέργειας

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Παραγωγή και Διαχείρηση Ενέργειας

Corticotropin-releasing hormone exerts direct effects on neuronal progenitor cells: implications for neuroprotection

Neurogenesis during embryonic and adult life is tightly regulated by a network of transcriptional, growth and hormonal factors. Emerging evidence indicates that activation of the stress response, via the associated glucocorticoid increase, reduces neurogenesis and contributes to the development of adult diseases.As corticotrophin-releasing hormone (CRH) or factor is the major mediator of adaptive response to stressors, we sought to investigate its involvement in this process. Accordingly, we found that CRH could reverse the damaging effects of glucocorticoid on neural stem/progenitor cells (NS/PCs), while its genetic deficiency results in compromised proliferation and enhanced apoptosis during neurogenesis. Analyses in fetal and adult mouse brain revealed significant expression of CRH receptors in proliferating neuronal progenitors. Furthermore, by using primary cultures of NS/PCs, we characterized the molecular mechanisms and identified CRH receptor-1 as the receptor mediating the neuroprotective effects of CRH. Finally, we demonstrate the expression of CRH receptors in human fetal brain from early gestational age, in areas of active neuronal proliferation. These observations raise the intriguing possibility for CRH-mediated pharmacological applications in diseases characterized by altered neuronal homeostasis, including depression, dementia, neurodegenerative diseases, brain traumas and obesity

Hypothalamus proteomics from mouse models with obesity and anorexia reveals therapeutic targets of appetite regulation

Objective: This study examined the proteomic profile of the hypothalamus in mice exposed to a high-fat diet (HFD) or with the anorexia of acute illness. This comparison could provide insight on the effects of these two opposite states of energy balance on appetite regulation.Methods: Four to six-week-old male C56BL/6J mice were fed a normal (control 1 group; n=7) or a HFD (HFD group; n=10) for 8 weeks. The control 2 (n=7) and lipopolysaccharide (LPS) groups (n=10) were fed a normal diet for 8 weeks before receiving an injection of saline and LPS, respectively. Hypothalamic regions were analysed using a quantitative proteomics method based on a combination of techniques including iTRAQ stable isotope labeling, orthogonal two-dimensional liquid chromatography hyphenated with nanospray ionization and high-resolution mass spectrometry. Key proteins were validated with quantitative PCR.Results: Quantitative proteomics of the hypothalamous regions profiled a total of 9249 protein groups (q<0.05). Of these, 7718 protein groups were profiled with a minimum of two unique peptides for each. Hierachical clustering of the differentiated proteome revealed distinct proteomic signatures for the hypothalamus under the HFD and LPS nutritional conditions. Literature research with in silico bioinformatics interpretation of the differentiated proteome identified key biological relevant proteins and implicated pathways. Furthermore, the study identified potential pharmacologic targets. In the LPS groups, the anorexigen pro-opiomelanocortin was downregulated. In mice with obesity, nuclear factor-?B, glycine receptor subunit alpha-4 (GlyR) and neuropeptide Y levels were elevated, whereas serotonin receptor 1B levels decreased.Conclusions: High-precision quantitative proteomics revealed that under acute systemic inflammation in the hypothalamus as a response to LPS, homeostatic mechanisms mediating loss of appetite take effect. Conversely, under chronic inflammation in the hypothalamus as a response to HFD, mechanisms mediating a sustained ‘perpetual cycle’ of appetite enhancement were observed. The GlyR protein may constitute a novel treatment target for the reduction of central orexigenic signals in obesity

Study of the role of BM88 protein in the commitment of cells to the neuronal lineage

BM88 is a neuron-specific protein widely expressed in the cells of the mammalian central and peripheral nervous system. Its biochemical characterization revealed that it is an integral membrane protein, located at the membranes of intracellular organelles (mitochondria, endoplasmic reticulum) with the bulk of the protein facing towards the cytoplasm. In the adult central nervous system BM88 is expressed in neurons but it is not detected in glial cells. During development, BM88 is initially expressed at the onset of neurogenesis in the rat brain, its levels rise with age and remain high in the adult. In vitro functional studies of BM88 over-expression in neuroblastoma cells suggest that BM88 is implicated in cell cycle exit and the initiation of differentiation towards a neuronal phenotype. These findings prompted us to study the expression of BM88 during neurogenesis and neuronal differentiation in vivo in order to investigate its role in brain development. For this reason, we have chosen as a model of study the developing rodent telencephalon. Initially, we investigated the distribution of BM88 protein in the developing cortex. To this end, we performed double-labeling experiments in sections from developing rat brain at embryonic days E14 and E18 using antibodies to BM88 and markers of the cell cycle such as cyclin D1 (G2/M phase marker) and bromo-2-deoxyuridine (BrdU), a thymidine analogue that is incorporated in DNA during its replication (S phase marker). The findings from these experiments revealed that BM88 protein is expressed in differentiated neurons, as well as in actively proliferating progenitor cells of the developing cortex of the rat and the mouse. We next sought to investigate whether BM88 is expressed during neurogenesis specifically in progenitor cells of the neuronal or glial lineage of telencephalon. To this end we performed double and triple-labeling experiments with antibodies to BM88 and to markers of the neuronal or glial lineages, in combination with markers of the cell cycle. We observed that BM88 protein is expressed exclusively in neuronal progenitors, but not in the proliferating or differentiated cells of the glial lineage. The above results were also supported by the fact that BM88 protein was detected in neuroepithelial “radial glial” cells that are which constitute the majority of neuronal progenitors in the cortex during embryonic days E14-E18. A subpopulation of these cells will turn into glial progenitors only after embryonic day E18 and during the early postnatal period. Moreover, we developed an experimental protocol that allowed us to mark a cohort of progenitor cells that exit the cell cycle in synchrony, using two different markers of the S phase of the cell cycle. Thus, we could observe in vivo, during a period of 12 to 24 hours, the migration and differentiation of a synchronized group of neural progenitor cells. The results from this experiment lead us to the conclusion that the expression of BM8 protein is associated with final asymmetric cell divisions that mark the onset of neurogenesis in the cortex and the generation of post-mitotic neurons. Thus, it appears that the expression of BM88 in neuronal progenitor cells drives them to exit from the cell cycle.Η πρωτεΐνη ΒΜ88 είναι νευροειδική πρωτεΐνη με ευρεία κατανομή σε κύτταρα του κεντρικού και περιφερικού νευρικού συστήματος των θηλαστικών. O βιοχημικός χαρακτηρισμός του μορίου έδειξε ότι πρόκειται για διαμεμβρανική πρωτεΐνη που εντοπίζεται κυρίως στις μεμβράνες ενδοκυττάριων οργανιδίων (μιτοχόνδρια, ενδοπλασματικό δίκτυο) ενώ το μεγαλύτερο τμήμα του μορίου της προσανατολίζεται προς το κυτταρόπλασμα. Στο ενήλικο κεντρικό νευρικό σύστημα η πρωτεΐνη ΒΜ88 εκφράζεται σε νευρώνες ενώ δεν ανιχνεύεται σε γλοιοκύτταρα. Αναπτυξιακά, η έκφραση της πρωτεΐνης ΒΜ88 ανιχνεύεται κατά την έναρξη της νευρογένεσης στον εγκέφαλο του αρουραίου ενώ τα επίπεδα της έκφρασή της αυξάνονται με την ηλικία και παραμένουν υψηλά στο ενήλικο ζώο. Λειτουργικά πειράματα in vitro υπερέκφρασης της πρωτεΐνης ΒΜ88 συσχετίζουν τη δράση του μορίου με την έξοδο των κυττάρων από τον κυτταρικό κύκλο και την έναρξη της διαδικασίας διαφοροποίησής τους προς νευρωνικό φαινότυπο. Τα παραπάνω δεδομένα μας ώθησαν να μελετήσουμε την έκφραση της πρωτεΐνης ΒΜ88 κατά τη διαδικασία της νευρογένεσης και της διαφοροποίησης των νευρώνων in vivo, έτσι ώστε να διερευνήσουμε το ρόλο της κατά την ανάπτυξη του εγκεφάλου. Για το σκοπό αυτό επιλέξαμε ως σύστημα μελέτης τον αναπτυσσόμενο φλοιό του τελεγκεφάλου των τρωκτικών. Αρχικά χαρτογραφήθηκε η έκφραση της πρωτεΐνης ΒΜ88 στο φλοιό του αναπτυσσόμενου τελεγκεφάλου κατά την εμβρυϊκή ηλικία Ε14-Ε18 και πραγματοποιήθηκαν πειράματα διπλού ανοσοφθορισμού με αντισώματα έναντι της πρωτεΐνης ΒΜ88 καθώς και μαρτύρων του κυτταρικού πολλαπλασιασμού όπως είναι η κυκλίνη D1 (μάρτυρας της φάσης G2/M του κυτταρικού κύκλου) και το ανάλογο της θυμιδίνης, βρωμο-2-δεοξυουριδίνη (BrdU), που ενσωματώνεται στο DNA κατά τη φάση της αντιγραφής του (φάση S του κυτταρικού κύκλου). Τα αποτελέσματα αυτών των πειραμάτων έδειξαν ότι η πρωτεΐνη ΒΜ88 εκφράζεται τόσο στους διαφοροποιημένους νευρώνες, όσο και σε ενεργά πολλαπλασιαζόμενα προγονικά κύτταρα στη κοιλιακή ζώνη του αναπτυσσόμενου φλοιού του αρουραίου και του ποντικού. Κατόπιν, διερευνήσαμε αν η πρωτεΐνη ΒΜ88 εκφράζεται κατά την περίοδο της νευρογένεσης ειδικά, σε προγονικά κύτταρα της γενεαλογίας των νευρώνων ή αν εκφράζεται και σε πρόδρομα κύτταρα της γλοιϊκής γενεαλογίας του τελεγκεφάλου. Για το σκοπό αυτό πραγματοποιήθηκαν διπλές και τριπλές ανοσοϊστοχημικές χρώσεις με αντισώματα έναντι της πρωτεΐνης ΒΜ88 καθώς και έναντι νευρωνικών ή γλοιΐκών μαρτύρων, σε συνδυασμό με αντισώματα έναντι μαρτύρων του κυτταρικού πολλαπλασιασμού. Παρατηρήθηκε ότι η πρωτεΐνη ΒΜ88 εκφράζεται αποκλειστικά και μόνο σε κύτταρα της νευρωνικής γενεαλογίας και όχι σε πολλαπλασιαζόμενα ή διαφοροποιημένα κύτταρα της γλοιϊκής γενεαλογίας. Τα παραπάνω αποτελέσματα επιβεβαιώθηκαν από το γεγονός ότι η έκφραση της πρωτεΐνης ΒΜ88 προσδιορίστηκε και σε νευροεπιθηλιακά κύτταρα του τύπου της «ακτινωτής γλοίας» που σύμφωνα με την τρέχουσα αντίληψη, αποτελούν την πλειοψηφία του πληθυσμού των πρόδρομων νευρογενετικών κυττάρων του φλοιού κατά την εμβρυϊκή ηλικία Ε14-Ε18. Αργότερα μόνο, ένας υποπληθυσμός αυτών των κυττάρων αυτά θα αποτελέσει προδρόμους της γλοιϊκής γενεαλογίας, και συγκεκριμένα μετά τη 18η εμβρυϊκή ημέρα έως και τις πρώτες ημέρες μετά τη γέννηση

Neural stem cells respond to stress hormones: distinguishing beneficial from detrimental stress

Neural stem cells (NSCs), the progenitors of the nervous system, control distinct, position-specific functions and are critically involved in the maintenance of homeostasis in the brain. The responses of these cells to various stressful stimuli are shaped by genetic, epigenetic, and environmental factors via mechanisms that are age and developmental stage-dependent and still remain, to a great extent, elusive. Increasing evidence advocates for the beneficial impact of the stress response in various settings, complementing the extensive number of studies on the detrimental effects of stress, particularly in the developing brain. In this review, we discuss suggested mechanisms mediating both the beneficial and detrimental effects of stressors on NSC activity across the lifespan. We focus on the specific effects of secreted factors and we propose NSCs as a “sensor,” capable of distinguishing among the different stressors and adapting its functions accordingly. All the above suggest the intriguing hypothesis that NSCs are an important part of the adaptive response to stressors via direct and indirect, specific mechanisms

Φωτοκαταλυτική οξείδωση οργανικών πτητικών ενώσεων σε αέρια φάση

64 σ.Η συγκεκριμένη διπλωματική εργασία πραγματεύεται τη διαχείριση των οργανικών πτητικών ενώσεων εφαρμόζοντας την τεχνική της φωτοκαταλυτικής οξείδωσης. Η διαπιστωμένη τοξικότητα και η επικινδυνότητα των οργανικών πτητικών ενώσεων, έχει εισαγάγει την ανάγκη αντιμετώπισης και διαχείρισής τους. Οι μέθοδοι που έχουν προταθεί για τη διαχείριση και καταστροφή των οργανικών πτητικών ενώσεων ποικίλλουν. Η φωτοκαταλυτική οξείδωση είναι μία τέτοια μέθοδος, η οποία καθίσταται ελκυστική λόγω του μειωμένου κόστους της. Τα πειράματα διενεργήθηκαν σε δακτυλιοειδή αντιδραστήρα με ανακύκλωση, συνεχούς έργου και συνθήκες περιβάλλοντος. Η παρασκευή των καταλυτών έγινε στο εργαστήριο και οι χρησιμοποιούμενοι καταλύτες είναι οι TiO2-P25, TiO2-Pt, TiO2-Ce, TiO2-Fe, isopropoxide ενώ ως αντιπροσωπευτικές ενώσεις VOCs χρησιμοποιήθηκαν το τολουόλιο, αιθυλοβενζόλιο, βενζόλιο, m-ξυλόλιο. Ο στόχος των πειραμάτων ήταν πρώτον η αποτελεσματικότητα της αντίδρασης των ενώσεων σε συγκεντρώσεις έως 40ppm, και δεύτερον η αποδοτικότητα των χρησιμοποιηθέντων καταλυτών. Σύμφωνα με τα πειραματικά αποτελέσματα και βασιζόμενοι στους ειδικούς ρυθμούς των αντιδράσεων, οι καταλύτες κατατάσσονται TiO2-Ce> TiO2-P25> TiO2-Pt > TiO2-Fe> isopropoxide με υψηλότερο επιτευκτέo ειδικό ρυθμό για την ένωση του αιθυλοβενζολίου k=101.29 ppmv*min-1. Αντίστοιχα η σύγκριση των ενώσεων για συγκέντρωση 10ppmv οδήγησε στο συμπέρασμα ότι φωτοκαταλυτική οξείδωση καθίσταται ικανή μέθοδος οξείδωσης για την ακόλουθη σειρά ενώσεων ξυλόλιο> βενζόλιο> τολουόλιο> αιθυλοβενζόλιο Οι υψηλότεροι μέγιστοι ρυθμοί επιτεύχθηκαν με τη χρήση TiO2-Ce για το αιθυλοβενζόλιο και το βενζόλιο και είναι αντίστοιχα 29,044 και 19,445 ppmv/min, ενώ οι σταθερές ρόφησης για όλες σχεδόν τις ενώσεις είναι KA<1 Τέλος προτείνονται μελλοντικά πειράματα ώστε να εξερευνηθεί περαιτέρω η φωτοκαταλυτική οξείδωση.This thesis deals with the management of volatile organic compounds by applying the technique of photocatalytic oxidation. The occurrence and toxicity of hazardous volatile organic compounds, has introduced the need to address and manage them. The methods have been proposed for the management and destruction of volatile organic compounds vary. The photocatalytic oxidation is one such method, which is attractive because of its lower cost. The experiments were performed in annular reactor with recycle, continuous work and environmental conditions. The preparation of the catalysts was in the laboratory and used catalysts are TiO2-P25, TiO2-Pt, TiO2-Ce, TiO2-Fe, isopropoxide and as representative compounds VOCs used toluene, ethylbenzene, benzene, m-xylene. The aim of the experiments was the first effective reaction of the compounds at concentrations up to 40ppm, and secondly the efficiency of the used catalysts. According to the experimental results and based on specific rates of reactions, the catalysts are classified TiO2-Ce> TiO2-P25> TiO2-Pt> TiO2-Fe> isopropoxide with higher epitefkteo special rate for the union of aithylovenzoliou k = 101.29 ppmv * min-1. Similarly the comparison of compounds at a concentration 10ppmv revealed that photocatalytic oxidation method is capable of oxidizing the following series of compounds xylene> benzene> toluene> ethylbenzene The higher maximum rates were achieved by using TiO2-Ce for ethylbenzene and benzene and are respectively 29.044 and 19,445 ppmv / min, while the adsorption constants for nearly all compounds are KA <1 Finally, proposed future experiments to further explore the photocatalytic oxidation.Κωνσταντίνα Σ. Κουτμάν

BM88 is an early marker of proliferating precursor cells that will differentiate into the neuronal lineage.

Progression of progenitor cells towards neuronal differentiation is tightly linked with cell cycle control and the switch from proliferative to neuron-generating divisions. We have previously shown that the neuronal protein BM88 drives neuroblastoma cells towards exit from the cell cycle and differentiation into a neuronal phenotype in vitro. Here, we explored the role of BM88 during neuronal birth, cell cycle exit and the initiation of differentiation in vivo. By double- and triple-labelling with the S-phase marker BrdU or the late G2 and M-phase marker cyclin B1, antibodies to BM88 and markers of the neuronal or glial cell lineages, we demonstrate that in the rodent forebrain, BM88 is expressed in multipotential progenitor cells before terminal mitosis and in their neuronal progeny during the neurogenic interval, as well as in the adult. Further, we defined at E16 a cohort of proliferative progenitors that exit S phase in synchrony, and by following their fate for 24&nbsp;h we show that BM88 is associated with the dynamics of neuron-generating divisions. Expression of BM88 was also evident in cycling cortical radial glial cells, which constitute the main neurogenic population in the cerebral cortex. In agreement, BM88 expression was markedly reduced and restricted to a smaller percentage of cells in the cerebral cortex of the Small eye mutant mice, which lack functional Pax6 and exhibit severe neurogenesis defects. Our data show an interesting correlation between BM88 expression and the progression of progenitor cells towards neuronal differentiation during the neurogenic interval

Corticotropin-releasing hormone exerts direct effects on neuronal progenitor cells: Implications for neuroprotection

Neurogenesis during embryonic and adult life is tightly regulated by a network of transcriptional, growth and hormonal factors. Emerging evidence indicates that activation of the stress response, via the associated glucocorticoid increase, reduces neurogenesis and contributes to the development of adult diseases.As corticotrophin-releasing hormone (CRH) or factor is the major mediator of adaptive response to stressors, we sought to investigate its involvement in this process. Accordingly, we found that CRH could reverse the damaging effects of glucocorticoid on neural stem/progenitor cells (NS/PCs), while its genetic deficiency results in compromised proliferation and enhanced apoptosis during neurogenesis. Analyses in fetal and adult mouse brain revealed significant expression of CRH receptors in proliferating neuronal progenitors. Furthermore, by using primary cultures of NS/PCs, we characterized the molecular mechanisms and identified CRH receptor-1 as the receptor mediating the neuroprotective effects of CRH. Finally, we demonstrate the expression of CRH receptors in human fetal brain from early gestational age, in areas of active neuronal proliferation. These observations raise the intriguing possibility for CRH-mediated pharmacological applications in diseases characterized by altered neuronal homeostasis, including depression, dementia, neurodegenerative diseases, brain traumas and obesity. © 2013 Macmillan Publishers Limited

Detrimental effects of adolescent escalating low-dose Δ9-tetrahydrocannabinol leads to a specific bio-behavioural profile in adult male rats

Background and Purpose: Adolescent cannabis use is associated with adult psychopathology. When Δ9-tetrahydrocannabinol (THC), mainly in high doses, is administered to adolescence rats there are also long lasting effects in adults. This study aims to determine the specific adult bio-behavioural profile after adolescent low-dose THC, which better mirrors adolescent recreational cannabis use. Experimental Approach: Adolescent male Sprague–Dawley rats were treated with escalating low-dose of THC. In adulthood, they were evaluated for their spontaneous locomotion, sensorimotor gating, higher order and spatial cognitive functions. Dopaminergic activity and cannabinoid receptor expression were measured in distinct brain regions. Hippocampal neurogenic activity of neural stem cells was determined and protein levels of neuroplasticity-related biomarkers were quantified. Adolescent low-dose THC exposure increased spontaneous open-field activity, without affecting prepulse inhibition and attentional set-shifting performance. Region-specific dopaminergic alterations and CB1 receptor up-regulation in the prefrontal cortex were observed. Impaired spatial memory, as assessed with the object location task and Morris water maze test, was associated with significantly decreased proliferative activity (SOX2-positive cells), neurogenic potential (decreased doublecortin-positive cells) in the adult hippocampus and defective neuroplasticity, including reduced BDNF expression in the hippocampus and prefrontal cortex. Key Results: Our findings reveal the adverse impact of adolescent low-dose THC on the psychomotor profile, dopaminergic neurotransmission, compensatory cannabinoid receptor response, cognition-related neurobiological and behavioural functions. Conclusion and Implications: Our adolescent low-dose THC animal model does not induce tangible psychotic-like effects, such as those reported in high-dose THC studies, but it impairs cognitive functions and points to hippocampal vulnerability and disrupted neurogenesis. © 2021 The British Pharmacological Societ

Hypothalamus proteomics from mouse models with obesity and anorexia reveals therapeutic targets of appetite regulation

OBJECTIVE: This study examined the proteomic profile of the hypothalamus in mice exposed to a high-fat diet (HFD) or with the anorexia of acute illness. This comparison could provide insight on the effects of these two opposite states of energy balance on appetite regulation. METHODS: Four to six-week-old male C56BL/6J mice were fed a normal (control 1 group; n = 7) or a HFD (HFD group; n = 10) for 8 weeks. The control 2 (n = 7) and lipopolysaccharide (LPS) groups (n = 10) were fed a normal diet for 8 weeks before receiving an injection of saline and LPS, respectively. Hypothalamic regions were analysed using a quantitative proteomics method based on a combination of techniques including iTRAQ stable isotope labeling, orthogonal two-dimensional liquid chromatography hyphenated with nanospray ionization and high-resolution mass spectrometry. Key proteins were validated with quantitative PCR. RESULTS: Quantitative proteomics of the hypothalamous regions profiled a total of 9249 protein groups (q &lt; 0.05). Of these, 7718 protein groups were profiled with a minimum of two unique peptides for each. Hierachical clustering of the differentiated proteome revealed distinct proteomic signatures for the hypothalamus under the HFD and LPS nutritional conditions. Literature research with in silico bioinformatics interpretation of the differentiated proteome identified key biological relevant proteins and implicated pathways. Furthermore, the study identified potential pharmacologic targets. In the LPS groups, the anorexigen pro-opiomelanocortin was downregulated. In mice with obesity, nuclear factor-kappa B, glycine receptor subunit alpha-4 (GlyR) and neuropeptide Y levels were elevated, whereas serotonin receptor 1B levels decreased. CONCLUSIONS: High-precision quantitative proteomics revealed that under acute systemic inflammation in the hypothalamus as a response to LPS, homeostatic mechanisms mediating loss of appetite take effect. Conversely, under chronic inflammation in the hypothalamus as a response to HFD, mechanisms mediating a sustained `perpetual cycle&apos; of appetite enhancement were observed. The GlyR protein may constitute a novel treatment target for the reduction of central orexigenic signals in obesity