Altered miRNA processing disrupts brown/white adipocyte determination and associates with lipodystrophy

miRNAs are important regulators of biological processes in many tissues, including the differentiation and function of brown and white adipocytes. the endoribonuclease dicer is a major component of the miRNA-processing pathway, and in adipose tissue, levels of dicer have been shown to decrease with age, increase with caloric restriction, and influence stress resistance. Here, we demonstrated that mice with a fat-specific KO of dicer develop a form of lipodystrophy that is characterized by loss of intra-abdominal and subcutaneous white fat, severe insulin resistance, and enlargement and whitening of interscapular brown fat. Additionally, KO of dicer in cultured brown preadipocytes promoted a white adipocyte-like phenotype and reduced expression of several miRNAs. Brown preadipocyte whitening was partially reversed by expression of miR-365, a miRNA known to promote brown fat differentiation; however, introduction of other miRNAs, including miR-346 and miR-362, also contributed to reversal of the loss of the dicer phenotype. Interestingly, fat samples from patients with HIV-related lipodystrophy exhibited a substantial downregulation of dicer mRNA expression. Together, these findings indicate the importance of miRNA processing in white and brown adipose tissue determination and provide a potential link between this process and HIV-related lipodystrophy.NIHEllison FoundationJoslin Diabetes and Endocrinology Research Center coresMary K. Iacocca ProfessorshipAcademy of FinlandSigrid Juselius FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Harvard Univ, Sch Med, Joslin Diabet Ctr, Sect Integrat Physiol & Metab, Boston, MA 02115 USAUniversidade Federal de São Paulo, Dept Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Program Mol Biol, São Paulo, BrazilAstraZeneca R&D, Cardiovasc & Metab Dis iMed, Molndal, SwedenUniv Helsinki, Dept Med, Helsinki, FinlandMinerva Fdn, Inst Med Res, Helsinki, FinlandUniv Massachusetts, Sch Med, Program Mol Med, Worcester, MA USAMassachusetts Gen Hosp, Program Nutr Metab, Boston, MA 02114 USAHarvard Univ, Sch Med, Boston, MA USAUniversidade Federal de São Paulo, Dept Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Program Mol Biol, São Paulo, BrazilNIH: DK082659NIH: DK033201NIH: AI060354NIH: DK040561NIH: U24-DK093000Joslin Diabetes and Endocrinology Research Center cores: DK036836FAPESP: 2010/52557-0Web of Scienc

Serum microRNA array analysis identifies miR-140-3p, miR-33b-3p and miR-671-3p as potential osteoarthritis biomarkers involved in metabolic processes.

Background: MicroRNAs (miRNAs) in circulation have emerged as promising biomarkers. In this study, we aimed to identify a circulating miRNA signature for osteoarthritis (OA) patients and in combination with bioinformatics analysis to evaluate the utility of selected differentially expressed miRNAs in the serum as potential OA biomarkers. Methods: Serum samples were collected from 12 primary OA patients, and 12 healthy individuals were screened using the Agilent Human miRNA Microarray platform interrogating 2549 miRNAs. Receiver Operating Characteristic (ROC) curves were constructed to evaluate the diagnostic performance of the deregulated miRNAs. Expression levels of selected miRNAs were validated by quantitative real-time PCR (qRT-PCR) in all serum and in articular cartilage samples from OA patients (n = 12) and healthy individuals (n = 7). Bioinformatics analysis was used to investigate the involved pathways and target genes for the above miRNAs. Results: We identified 279 differentially expressed miRNAs in the serum of OA patients compared to controls. Two hundred and five miRNAs (73.5%) were upregulated and 74 (26.5%) downregulated. ROC analysis revealed that 77 miRNAs had area under the curve (AUC) > 0.8 and p < 0.05. Bioinformatics analysis in the 77 miRNAs revealed that their target genes were involved in multiple signaling pathways associated with OA, among which FoxO, mTOR, Wnt, pI3K/akt, TGF-β signaling pathways, ECM-receptor interaction, and fatty acid biosynthesis. qRT-PCR validation in seven selected out of the 77 miRNAs revealed 3 significantly downregulated miRNAs (hsa-miR-33b-3p, hsa-miR-671-3p, and hsa-miR-140-3p) in the serum of OA patients, which were in silico predicted to be enriched in pathways involved in metabolic processes. Target-gene analysis of hsa-miR-140-3p, hsa-miR-33b-3p, and hsa-miR-671-3p revealed that InsR and IGFR1 were common targets of all three miRNAs, highlighting their involvement in regulation of metabolic processes that contribute to OA pathology. Hsa-miR-140-3p and hsa-miR-671-3p expression levels were consistently downregulated in articular cartilage of OA patients compared to healthy individuals. Conclusions: A serum miRNA signature was established for the first time using high density resolution miR-arrays in OA patients. We identified a three-miRNA signature, hsa-miR-140-3p, hsa-miR-671-3p, and hsa-miR-33b-3p, in the serum of OA patients, predicted to regulate metabolic processes, which could serve as a potential biomarker for the evaluation of OA risk and progression.Peer reviewedFinal Published versio

Design and Study of Pillared Graphenes and Nanoporous Carbon Materials for Energy, Environmental and Catalytic Applications

Nanoporous materials have been exploited since antiquity in a plethora of applications due to their controllable pore size, diverse geometries, surface properties and their ability to interact with molecules and atoms or adsorb/release them. Being amongst the most abundant elements on earth and present in a variety of forms, carbon is an excellent candidate material for applications that can pave the way for a greener, waste-free, and less energy- and resource-demanding future and new forms of porous carbon have an important role to play in this context. Porosity in materials can be obtained in many ways; in this PhD project the focus lay on porous carbons resulting from carbonization, chemical etching, template synthesis and activation, or ‘Parthenon like’ structures. The latter were constructed through the intercalation of robust organic and/or inorganic pillars between graphene sheets in order to keep the layers apart and create interconnected void spaces with a well-defined size and chemical affinity. Towards this aim, two new composites, on where a silica network was created in the interlayer space of organically modified graphene oxide, and another one where graphene oxide was pillared with silsesquioxanes, were tested as CO2 sorbents. We also explored the ability of copper-enriched porous carbon cuboids to capture H2S gas and showed how hierarchical porous carbons with high specific surface areas and pore volumes can be produced making use of sugar and coffee wastes

Organ specificity of template activity of mammalian chromatin

Cell differentiation is correlated with, the differential activity of genes in a given cell (and by implication in a functionally defined mixture of cell types, i.e. a tissue). One of the topics of major Importance in differentiation is concerned with the proportion of the genome which is active in RNA synthesis, i.e. the relative amount of genomic information which brings about the morphological changes characteristic of adult tissues. The template specificity of isolated chromatins in supporting RNA synthesis t/as studied in order to clarify the relationship between genomic expression and organ specificity. The molecular hybridization technique was used for RNAs transcribed vitro from several mouse chromatins. This technique provides a sensitive method for distinguishing between various populations of RNA molecules. It was found first that different populations of RNA molecules examined are not only distinguishable but also show large differences among them and second, that only a part of the genome was active in transcription. By competition experiments it was found that the RNAs produced by chromatin in a cell-free RNA system were similar to RNAs isolated from the whole homologous tissue. This provides evidence that the template specificity associated with chromosomes in vivo is retained by isolated chromatin. A particular feature of this study is the high degree of reproducibility of the hybridisation values for each tissue and the dissimilarities displayed by the different tissues. When DNA from mouse kidney was used as template in a cell free system and the RNA produced was annealed, then the amount of hybridisation was almost three times greater than the hybridization which occurred when chromatin was used as template. From these results it appears that many of the genes in animal somatic cells, which are considered as being in a completely differentiated state, are in fact inactive in supporting RNA synthesis, the inactivation pattern of the genome in such cells being distinctive for each tissue. The mechanisms which control cell division in mammalian organs are not understood. Various experimental models have been used to study this problem. The cases under investigation include in vivo models, i.e. induction by folic acid of RNA synthesis in mouse kidneys and the appearance of new species of RNA in mouse kidneys after the ligature of one ureter. Studies have been made on the effect of folio acid administration in stimulating changes in the vitro RNA synthesis such that new kinds of RNA molecules appear in mouse kidney at specific times after the treatment. The ability of kidney chromatin in supporting RNA synthesis has been studied in untreated (control) and treated animals. It was found that folic acid changes profoundly the template activity of the isolated chromatin from mouse kidneys, RNA transcribed from chromation at early stages hybridizes with twice as much DNA as RNA transcribed from normal chromatin. By competition experiments it was confirmed that the cell free system produces the same RNA species as are found vivo which indicates that the integrity of the chromatin is maintained during isolation. Furthermore, the experiments showed that new kinds of RNA molecules are transcribed from kidney chromatin after the early hours of folate. The transcriptional activity of the genome eventually falls to the control level after two days. Another method for stimulating the appearance of new species of RNA in mouse kidneys is to ligate one ureter. The template activity of chromatin from the ligated kidney has been investigated from aero hours until 48 hours. The maximum hybridization efficiency (twice the control) is exhibited at 36 hours while RNA transcribed from chromatin isolated at early stages hybridizes with as much DNA as RNA transcribed from normal chromatin. The purpose of these experiments has been to compare the template activity of chromatin isolated at various times after the ligature of one ureter with those obtained after folic acid treatment in mice and to determine if the same control mechanism operates in both phenomena. The relationship between these two systems is discussed

Advances in fluorescent carbon dots for biomedical applications

Carbon Dots are an emerging class of carbon-based nanoparticles, which since their discovery have attracted tremendous attention because of their exceptional fluorescent, chemical and mechanical properties as well as high photostability and biocompatibility. This unique combination of outstanding characteristics, together with the ease with which they can be synthesized, qualify carbon dots as highly promising materials for applications in electronics and biology, in particular, for biosensing, bioimaging, biotherapy and drug delivery. In this review, we present some of the most recent applications of carbon dots in biology and medicine, concentrating on their fluorescence properties, biocompatibility and efficiency; we also discuss how improvements could prompt their use in human studies. We illustrate how carbon dots, prepared through several facile and cost-effective methods by either the bottom-up or the top-down route, can be used for imaging cells and bacteria and as sensing probes of metal cations. Moreover, we explain how their astonishing versatility has given rise to new biotherapy methods especially in the field of cancer theranostics

the case of early handling

Οι εξωγενείς παρεμβάσεις στα πρώιμα στάδια της ζωής μελετώνται σε τρωκτικά για να διερευνηθεί ποιά είναι η επίδρασή τους κατά την ενηλικίωση. Ο πρώιμος χειρισμός (early handling / EH) είναι μια παρέμβαση της πρώιμης ζωής που περιλαμβάνει τον σύντομο και επαναλαμβανόμενο αποχωρισμό των νεογνών από τη μητέρα τους τις πρώτες ημέρες μετά τη γέννηση και έχει αποδειχθεί ότι επάγει ευεργετικά αποτελέσματα στην ενήλικη ζωή. Ωστόσο, το ποιές είναι οι επιδράσεις του ΕΗ σε ένα υπόβαθρο υψηλού άγχους και το πώς τα μιτοχόνδρια ρυθμίζουν αυτές τις επιδράσεις δεν έχουν διερευνηθεί. Για να μελετήσουμε αυτά τα ερωτήματα, χρησιμοποιήσαμε ένα μοντέλο ποντικιών υψηλού (ΗΑΒ) και φυσιολογικού άγχους (ΝΑΒ). Προηγούμενα πειράματα του εργαστηρίου έδειξαν ότι το EH επάγει αγχολυτικά αποτελέσματα σε ενήλικα αρσενικά ΗΑΒ ποντίκια και αλλάζει τα επίπεδα mRNA γονιδίων στον προμετωπιαίο φλοιό που σχετίζονται με τη μιτοχονδριακή δυναμική, η οποία αφορά στις διαδικασίες της μιτοχονδριακής βιογένεσης, σχάσης, σύντηξης και μιτοφαγίας. Στόχος στην παρούσα διατριβή ήταν να συνεχίσουμε τον μοριακό χαρακτηρισμό των επιδράσεων EH στα μιτοχόνδρια, τόσο στον προμετωπιαίο φλοιό αλλά και στον υποθάλαμο και τον ιππόκαμπο, περιοχές που εμπλέκονται σε εγκεφαλικά δίκτυα που ρυθμίζουν το άγχος. Χρησιμοποιώντας Western blot, qRT-PCR, δοκιμασίες ολικής αντιοξειδωτικής ικανότητας και καρβονυλίωσης, ανακαλύψαμε ότι το EH δεν επηρεάζει το οξειδωτικό στρες και την οξειδωτική φωσφορυλίωση σε καμία από τις μελετηθείσες εγκεφαλικές περιοχές, αλλά αυξάνει την έκφραση γλυκολυτικών ενζύμων στον υποθάλαμο. Επίσης, το EH αυξάνει τα επίπεδα πρωτεϊνών της μιτοχονδριακής δυναμικής στον υποθάλαμο καθώς και τα επίπεδα mRNA γονιδίων σχετιζόμενων με μιτοχονδριακή δυναμική. Τέλος, τα επίπεδα καρβονυλίωσης στον προμετωπιαίο φλοιό αλλά και η αντιοξειδωτική ικανότητα στον ιππόκαμπο συσχετίζονται με τη σχετική με το άγχος συμπεριφορά. Τα αποτελέσματά μας αναδεικνύουν τον ρόλο των μιτοχονδρίων και της μιτοχονδριακής δυναμικής στην επαγόμενη από το ΕΗ αγχόλυση στα HAB αρσενικά ποντίκια και μπορούν να συνεισφέρουν στην ανακάλυψη νέων θεραπευτικών στόχων για την αντιμετώπιση των διαταραχών άγχους.Early life manipulations are studied in rodents to disentangle how they shape later life outcomes. Early Handling (EH) is an early life intervention consisting of the brief and repeated separation of the pups from their mother during the first days after birth, which has been shown to exert beneficial effects in adulthood. However, which are the EH effects in a high anxiety background and how brain mitochondria regulate these effects have not been yet investigated. To address these questions, we applied EH in mice of high (HAB) and normal (NAB) anxiety-related behavior. Previous experiments from our lab showed that EH induces anxiolysis in HAB adult male mice and alters prefrontal cortex mRNA levels of key players of mitochondrial dynamics, which includes the molecular machinery of mitochondrial biogenesis, fission, fusion and mitophagy. The aim of this thesis was to expand the molecular characterization of EH in the prefrontal cortex but also in hypothalamus and hippocampus, which are brain regions involved in anxiety neurocircuits. Using Western blots, qRT- PCRs, total antioxidant capacity (TAC) and carbonylation assays, we discovered that EH exerts no effect on oxidative stress or oxidative phosphorylation in all brain regions studied, but increases glycolytic enzyme expression in the hypothalamus. Furthermore, we found that EH increases mitochondrial dynamics protein levels in the hypothalamus as well as mRNA levels of mitochondrial dynamics-related genes. Finally, carbonylation levels in the prefrontal cortex and TAC in the hippocampus correlate with anxiety-related behavior. Our results highlight the role of mitochondria and mitochondrial dynamics in the EH-induced anxiolysis in HAB male mice in a brain region-specific manner and can contribute to the discovery of candidate therapeutic targets for the treatment of anxiety disorders.109 σ

Η ενδυνάμωση της κοινωνικής συνείδησης των μαθητών μέσω των πολιτιστικών εκδηλώσεων στο Δημοτικό Σχολείο

Η σύγχρονη εκπαίδευση έχει ως βασικό σκοπό να προετοιμάσει τους μαθητές ώστε να είναι σε θέση να αντιδρούν γρήγορα και να ανταπεξέρχονται στις επιταγές των καιρών ως ενεργοί και δυναμικοί πολίτες, με δημοκρατικό ήθος, ηθική και γνωστική αυτονομία. Αντικείμενο της παρούσας εργασίας αποτελεί η διερεύνηση του τρόπου με τον οποίο η εκπαίδευση, και πιο συγκεκριμένα οι πολιτιστικές εκδηλώσεις στο σχολείο μπορούν να συμβάλλουν στην ενδυνάμωση της κοινωνικής συνείδησης των μαθητών. Οι υγιείς αλληλεπιδραστικές σχέσεις ανάμεσα στα μέλη της κοινωνίας έχουν δώσει τη θέση τους σε σχέσεις ακραίου ανταγωνισμού, οι οποίες συχνά επεκτείνονται και στο χώρο του σχολείου. Η ανάγκη για συνειδητοποίηση ότι αποτελούμε μέλη ενός αδιάσπαστου συνόλου, καθώς και η αντίληψη πως η συλλογική δράση είναι η απάντηση στα σύγχρονα κοινωνικά, πολιτικά και οικονομικά παγκόσμια προβλήματα, μας οδήγησε στην επιλογή του συγκεκριμένου θέματος. Οι σχολικές εορταστικές εκδηλώσεις, χάρη στη μεγάλη θεματολογική τους ποικιλία, την αυξημένη παιδαγωγική τους αξία, την αξιοποίηση του θεάτρου και των άλλων μορφών τέχνης, αλλά και τη συμμετοχή των μαθητών στις ομάδες εργασίας, αποδεικνύονται ισχυρό εργαλείο κοινωνικής και πολιτικής διαπαιδαγώγησης στα χέρια του εκπαιδευτικού.Modern education’s primary objective is to prepare students to be able to react effectively and respond to the actual imperatives as active and dynamic citizens with a democratic mindset, moral and cognitive autonomy. The purpose of this paper is to investigate how education, and especially cultural events in school, can help to strengthen the students&apos; social consciousness. Healthy interactive relationships between members of a society have been replaced by extreme competition, which often extends within the school. The need of realizing that we are members of an inseparable whole, as well as the notion that collective action is the answer to current social, political and economic world problems, has led to the choice of this particular subject. The school celebrations, thanks to their increased pedagogical value, the use of theater and other forms of art, as well as the participation of pupils in working groups, prove to be powerful tools of social and political education in the hands of the teacher

H₂S removal by copper enriched porous carbon cuboids

Hydrogen sulfide (H2S) removal by adsorption from gas streams is crucial to prevent the environmental and industrial damage it causes. Amongst the nanostructures considered excellent candidates as sorbents, porous carbon has been studied extensively over the last years. In the present work we present a synthetic procedure for three high potential sorbents based on carbon cuboids, namely a low-surface-area copper-rich structure, a highly porous aggregate without metal addition, and lastly the same porous carbon decorated with copper. The properties and performance as catalysts of these three sorbents were evaluated by powder X-ray diffraction, X-ray photoelectron spectroscopy, thermal analysis, scanning electron microscopy with energy dispersive X-ray analysis, surface area determination through N2 adsorption and desorption, as well as by H2S adsorption measurements

Highly Efficient Remediation of Chloridazon and Its Metabolites:The Case of Graphene Oxide Nanoplatelets

The contamination of aqueous environments by aromatic pollutants has become a global issue. Chloridazon, a herbicide considered as harmless to the ecosystem, has been widely used in recent decades and has accumulated, together with its degradation products desphenyl-chloridazon and methyl-desphenyl-chloridazon, to a non-negligible level in surface water and groundwater. To respond to the consequent necessity for remediation, in this work, we study the adsorption of chloridazon and its metabolites by graphene oxide and elucidate the underlying mechanism by X-ray photoelectron spectroscopy. We find a high adsorption capacity of 67 g kg-1for chloridazon and establish that bonding of chloridazon to graphene oxide is mainly due to hydrophobic interaction and hydrogen bonding. These findings demonstrate the potential of graphene-based materials for the remediation of chloridazon and its metabolites from aqueous environments