Modulation of rhodopsin gene expression and signaling mechanisms evoked by endothelins in goldfish and murine pigment cell lines

Endothelins (ETs) and sarafotoxins (SRTXs) belong to a family of vasoconstrictor peptides, which regulate pigment migration and/or production in vertebrate pigment cells. The teleost Carassius auratus erythrophoroma cell line, GEM-81, and Mus musculus B16 melanocytes express rhodopsin, as well as the ET receptors, ETB and ETA, respectively. Both cell lines are photoresponsive, and respond to light with a decreased proliferation rate. For B16, the doubling time of cells kept in 14-h light (14L):10-h darkness (10D) was higher compared to 10L:14D, or to DD. The doubling time of cells kept in 10L:14D was also higher compared to DD. Using real-time PCR, we demonstrated that SRTX S6c (12-h treatment, 100 pM and 1 nM; 24-h treatment, 1 nM) and ET-1 (12-h treatment, 10 and 100 pM; 24- and 48-h treatments, 100 pM) increased rhodopsin mRNA levels in GEM-81 and B16 cells, respectively. This modulation involves protein kinase C (PKC) and the mitogen-activated protein kinase cascade in GEM-81 cells, and phospholipase C, Ca2+, calmodulin, a Ca2+/calmodulin-dependent kinase, and PKC in B16 cells. Cells were kept under constant darkness throughout the gene expression experiments. These results show that rhodopsin mRNA levels can be modulated by SRTXs/ETs in vertebrate pigment cells. It is possible that SRTX S6c binding to the ETB receptors in GEM-81 cells, and ET-1 binding to ETA receptors in B16 melanocytes, although activating diverse intracellular signaling mechanisms, mobilize transcription factors such as c-Fos, c-Jun, c-Myc, and neural retina leucine zipper protein. These activated transcription factors may be involved in the positive regulation of rhodopsin mRNA levels in these cell lines.

Mapping and signaling of neural pathways involved in the regulation of hydromineral homeostasis

Several forebrain and brainstem neurochemical circuitries interact with peripheral neural and humoral signals to collaboratively maintain both the volume and osmolality of extracellular fluids. Although much progress has been made over the past decades in the understanding of complex mechanisms underlying neuroendocrine control of hydromineral homeostasis, several issues still remain to be clarified. The use of techniques such as molecular biology, neuronal tracing, electrophysiology, immunohistochemistry, and microinfusions has significantly improved our ability to identify neuronal phenotypes and their signals, including those related to neuron-glia interactions. Accordingly, neurons have been shown to produce and release a large number of chemical mediators (neurotransmitters, neurohormones and neuromodulators) into the interstitial space, which include not only classic neurotransmitters, such as acetylcholine, amines (noradrenaline, serotonin) and amino acids (glutamate, GABA), but also gaseous (nitric oxide, carbon monoxide and hydrogen sulfide) and lipid-derived (endocannabinoids) mediators. This efferent response, initiated within the neuronal environment, recruits several peripheral effectors, such as hormones (glucocorticoids, angiotensin II, estrogen), which in turn modulate central nervous system responsiveness to systemic challenges. Therefore, in this review, we shall evaluate in an integrated manner the physiological control of body fluid homeostasis from the molecular aspects to the systemic and integrated responses.

Global microRNA profiles and signaling pathways in the development of cardiac hypertrophy

Hypertrophy is a major predictor of progressive heart disease and has an adverse prognosis. MicroRNAs (miRNAs) that accumulate during the course of cardiac hypertrophy may participate in the process. However, the nature of any interaction between a hypertrophy-specific signaling pathway and aberrant expression of miRNAs remains unclear. In this study, Spague Dawley male rats were treated with transverse aortic constriction (TAC) surgery to mimic pathological hypertrophy. Hearts were isolated from TAC and sham operated rats (n=5 for each group at 5, 10, 15, and 20 days after surgery) for miRNA microarray assay. The miRNAs dysexpressed during hypertrophy were further analyzed using a combination of bioinformatics algorithms in order to predict possible targets. Increased expression of the target genes identified in diverse signaling pathways was also analyzed. Two sets of miRNAs were identified, showing different expression patterns during hypertrophy. Bioinformatics analysis suggested the miRNAs may regulate multiple hypertrophy-specific signaling pathways by targeting the member genes and the interaction of miRNA and mRNA might form a network that leads to cardiac hypertrophy. In addition, the multifold changes in several miRNAs suggested that upregulation of rno-miR-331*, rno-miR-3596b, rno-miR-3557-5p and downregulation of rno-miR-10a, miR-221, miR-190, miR-451 could be seen as biomarkers of prognosis in clinical therapy of heart failure. This study described, for the first time, a potential mechanism of cardiac hypertrophy involving multiple signaling pathways that control up- and downregulation of miRNAs. It represents a first step in the systematic discovery of miRNA function in cardiovascular hypertrophy.

Imbalanced expression of functional surface molecules in regulatory and effector T cells in systemic lupus erythematosus

Regulatory T (TREG) cells play an important role in maintaining immune tolerance and avoiding autoimmunity. We analyzed the expression of membrane molecules in TREG and effector T cells in systemic lupus erythematosus (SLE). TREG and effector T cells were analyzed for the expression of CTLA-4, PD1, CD28, CD95, GITR, HLA-DR, OX40, CD40L, and CD45RO in 26 patients with active disease, 31 with inactive disease, and 26 healthy controls. TREG cells were defined as CD25+/highCD127Ø/lowFoxP3+, and effector T cells were defined as CD25+CD127+FoxP3Ø. The ratio of TREG to effector T cells expressing GITR, PD1, HLA-DR, OX40, CD40L, and CD45RO was determined in the three groups. The frequency of TREG cells was similar in patients with SLE and controls. However, SLE patients had a decreased frequency of CTLA-4+TREG and CD28+TREG cells and an increased frequency of CD40L+TREG cells. There was a decrease in the TREG/effector-T ratio for GITR+, HLA-DR+, OX40+, and CD45RO+ cells, and an increased ratio of TREG/effector-T CD40L+ cells in patients with SLE. In addition, CD40L+TREG cell frequency correlated with the SLE disease activity index (P=0.0163). In conclusion, our findings showed several abnormalities in the expression of functionally critical surface molecules in TREG and effector T cells in SLE that may be relevant to the pathogenesis of this disease.

Networking Notch : regulation of Notch traffic and signaling crosstalk

Utvecklingen av flercelliga organismer är en mångfacetterad process som kräver kommunikation celler emellan. Under utvecklingen av en organism måste cellerna göra vissa val, vilket bestämmer riktningen för deras fortsatta utveckling. Utgående från dessa val erhåller cellerna egenskaper som är karaktäristiska för olika celltyper. Notch-signalräckan är en viktig reglerare av valet mellan olika cellöden. Notch-signalräckan aktiveras när Notch-receptorer som uttrycks på ytan av en cell binder till Notch-ligander som uttrycks på ytan av en annan närliggande cell. Denna avhandling belyser mekanismerna som reglerar omsättningen av såväl Notch-receptorer som -ligander till och från cellmembranen, samt ökar förståelsen för hur dessa mekanismer påverkar Notch-medierade cellöden i stamceller. Internalisering av Notch receptorer anses nödvändigt för fullständig aktivering av Notch-signalvägen. De bakomliggande molekylära mekanismerna är dock fortfarande oklara. Vi har upptäckt att atypiskt protein kinas Cζ (aPKCζ) reglerar internaliseringen av Notch-receptorer. aPKCζ fosforylerar Notch, vilket leder till receptorns internalisering, men effekten är beroende av receptorns signaleringsstatus. Vi visar att aPKCζ reglerar Notch-signaleringen och styr både neuroners och muskelcellers differentiering. Ytterligare har vi analyserat samspelet mellan cellskelettet och Notch-signalvägen. Våra resultat visar att intermediärfilamenten, en del av cellskelettet, är viktiga reglerare av Notch-signaleringen både under neuronal och vaskulär utveckling. Intermediärfilamenten vimentin och GFAP reglerar uttrycket av Notch-ligander vid cellmembranen i hjärnans stödceller, astrocyterna, och påverkar därmed neuronala stamcellers cellödesbeslut. Vimentin är även viktigt reglerare av Notch-signalräckan vid angiogenesen. Celler som saknar vimentin uppvisar avvikande Notch-signalering emedan möss som saknar vimentin påvisar en fördröjd utveckling av vaskulaturen under embryonalstadiet. ------------------------------------------------- Monisoluisten organismien kehittyminen on monimutkainen prosessi, joka vaatii viestintää solujen välillä. Kehittymisen aikana solut joutuvat tiettyjen valintojen eteen, mitkä tulevat määrittämään niiden erilaistumisen suunnan. Solut omaksuvat solutyypille ominaisia ominaisuuksia näihin valintoihin perustuen Notch-signalointireitti säätelee solujen erilaistumista eri suuntiin. Notch-signalointireitti aktivoituu, kun Notch-reseptori yhden solun pinnalla sitoo Notch-ligandin toisen, viereisen solun solukalvolla. Tutkimukseni lisää tuntemusta Notch-reseptoreiden ja ligandien solun sisäisestä liikennöinnistä ja sitä säätelevistä mekanismeista, sekä tämän säätelyn vaikutuksista kantasulojen erilaistumiseen. Notch-signalointireitin aktivoituminen vaatii reseptoreiden ja ligandien sisäistämisen solukalvolta, mutta taustalla olevat ja sisäistymistä säätelevät mekanismit ovat vielä epäselviä. Tutkimukseni osoittaa, että atyyppinen proteiinikinaasi Cζ (aPKCζ) säätelee Notch-reseptoreiden endosytoosia. Endosytoosin lopputulos riippuu siitä onko reseptori aktivoitunut ligandin välityksellä vai ei. Tuloksemme osoittavat aPKCζ säätelevän Notch-signalointia ja kontrolloivan sekä hermosolujen, että lihassolujen erilaistumista. Analysoimme myös Notch-signaloinnin ja solun tukirangan vuorovaikutuksia. Välikokoiset filamentit, jotka ovat osa tukirankaa, säätelevät Notch-signalointia neuronaalisen erilaistumisen sekä verisuonten uudismuodostumisen aikana. Vimentiini ja GFAP ovat välikokoisia säikeitä, jotka säätelevät Notch-ligandien ekspressiota astrosyyttien, eli aivojen hermotukisolujen solukalvolla. Vimentiini säätelee myös Notch-signalointireittiä angiogeneesin aikana. Vimentiiniä vailla olevilla soluilla ilmenee heikentynyttä Notch-signalointia, joka voidaan liittää hiirillä ilmenevään vimenttiinin puutteesta johtuvaan viivästyneeseen verisuonien kehitykseen.

Helsinki hub – new traffic flows and business networks

This thesis is the Logistics Development Forum's assignment and the work dealing with the development of the Port of Helsinki as part of Helsinki hub. The Forum aims to develop logistics efficiency through public-private co-operation and development of the port is clearly dependent on both factors. Freight volumes in the Port of Helsinki are the biggest single factor in hub and, therefore, the role of the port of the entire hub development is strong. The aim is to look at how the port will develop as a result of changes in the foreign trade of Finland and the Northern European logistics trends in 25 years time period. Work includes the current state analysis and scenario work. The analyses are intended to find out, which trends are the most important in the port volume development. The change and effect of trends is examined through scenarios based on current state. Based on the work, the structure of Finnish export industry and international demand are in the key role in the port volume development. There is significant difference between demands of Finnish exporting products in different export markets and the development between the markets has different impacts on the port volumes by mass and cargo type. On the other hand, the Finnish economy is stuck in a prolonged recession and competition between ports has become a significant factor in the individual port's volume development. Ecological valuesand regulations have changed the competitive landscape and maritime transport emissions reductions has become an important competitive factor for short routes in the Baltic Sea, such as in the link between Helsinki and Tallinn.

Credibility and Signaling in Disinflation- a Cross Country Examination

This paper develops a model of money demand where the opportunity cost of holding money is subject to regime changes. The regimes are fully characterized by the mean and variance of inflation and are assumed to be the result of alternative government policies. Agents are unable to directly observe whether government actions are indeed consistent with the inflation rate targeted as part of a stabilization program but can construct probability inferences on the basis of available observations of inflation and money growth. Government announcements are assumed to provide agents with additional, possibly truthful information regarding the regime. This specification is estimated and tested using data from the Israeli and Argentine high inflation periods. Results indicate the successful stabilization program implemented in Israel in July 1985 was more credible than either the earlier Israeli attempt in November 1984 or the Argentine programs. Government’s signaling might substantially simplify the inference problem and increase the speed of learning on the part of the agents. However, under certain conditions, it might increase the volatility of inflation. After the introduction of an inflation stabilization plan, the welfare gains from a temporary increase in real balances might be high enough to induce agents to raise their real balances in the short-term, even if they are uncertain about the nature of government policy and the eventual outcome of the stabilization attempt. Statistically, the model restrictions cannot be rejected at the 1% significance level.

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Entrepreneurship, ties and relational networks: the case of a public-private cross-border tourism product

The thesis aims to understand the processes of entrepreneurship that try to create businesses or products with a high degree of complexity. This complexity comes from the fact that these products or initiatives can only be viable with the concurrence of a large number of heterogeneous actors (public, private, from different regions, etc..) which interact in a relational context. A case with these characteristics is the Camí dels Bons Homes. The thesis analyzes the evolution of the relational network from the point of view of its structure and content of its links. The results show and explain the observed changes in the network structure and the changes in the ties content. This analysis of the content of ties contributes to a new systematization and operationalization of ties’ content. Moreover this analysis takes in account negative ties, a less discussed issue in literature.