Effects of NR1 splicing on NR1/NR3B-type excitatory glycine receptors

BACKGROUND: N-methyl-D-aspartate receptors (NMDARs) are the most complex of ionotropic glutamate receptors (iGluRs). Subunits of this subfamily assemble into heteromers, which – depending on the subunit combination – may display very different pharmacological and electrophysiological properties. The least studied members of the NMDAR family, the NR3 subunits, have been reported to assemble with NR1 to form excitatory glycine receptors in heterologous expression systems. The heterogeneity of NMDARs in vivo is in part conferred to the receptors by splicing of the NR1 subunit, especially with regard to proton sensitivity. RESULTS: Here, we have investigated whether the NR3B subunit is capable of assembly with each of the eight functional NR1 splice variants, and whether the resulting receptors share the unique functional properties described for NR1-1a/NR3. We provide evidence that functional excitatory glycine receptors formed regardless of the NR1 isoform, and their pharmacological profile matched the one reported for NR1-1a/NR3: glycine alone fully activated the receptors, which were insensitive to glutamate and block by Mg(2+). Surprisingly, amplitudes of agonist-induced currents showed little dependency on the C-terminally spliced NR1 variants in NR1/NR3B diheteromers. Even more strikingly, NR3B conferred proton sensitivity also to receptors containing NR1b variants – possibly via disturbing the "proton shield" of NR1b splice variants. CONCLUSION: While functional assembly could be demonstrated for all combinations, not all of the specific interactions seen for NR1 isoforms with coexpressed NR2 subunits could be corroborated for NR1 assembly with NR3. Rather, NR3 abates trafficking effects mediated by the NR1 C terminus as well as the N-terminally mediated proton insensitivity. Thus, this study establishes that NR3B overrides important NR1 splice variant-specific receptor properties in NR1/NR3B excitatory glycine receptors

Neuropatia uditiva: incidenza e caratteristiche cliniche in neonati a rischio

INTRODUZIONE La neuropatia uditiva (NU), entità nosografica di recente individuazione, costituisce un’importante causa di ipoacusia di grado variabile dal lieve al severo, ad insorgenza sia nella primissima infanzia che nell’età giovanile, raramente nell’anziano. È riconducibile ad alterazioni di alcune componenti della via uditiva, tra cui le cellule cocleari ciliate interne (le esterne sono caratteristicamente risparmiate), le loro sinapsi con le fibre afferenti del nervo acustico o il nervo acustico stesso. L’eziologia, fatta eccezione per le forme riconducibili a mutazioni del gene OTOF (codificante per l’otoferlina, una proteina espressa dalle cellule ciliate interne cocleari), è stata posta in relazione con differenti fattori di rischio. In particolare, diversi studi hanno evidenziato una maggiore incidenza di NU tra i neonati ricoverati in UTIN o esposti, in epoca perinatale, a particolari condizioni quali iperbilirubinemia, anossia, patologie infettive, farmaci ~ 239 ~ ototossici. MATERIALI E METODI Dato il caratteristico profilo audiologico la diagnosi necessita della registrazione contemporanea delle OAEs (presenti in quanto integre le cellule ciliate esterne) e delle risposte ABR che risultano alterate, desincronizzate o addirittura irriconoscibili. Si rileva anche l’assenza del riflesso stapediale, sia ipsi che controlateralmente. RISULTATI Il nostro studio ha rilevato, in un campione di 110 bambini ricoverati in UTIN per un periodo > 5 giorni, 15 soggetti con deficit uditivo, tra i quali sono stati individuati 4 casi (26,6%) con profilo audiologico compatibile con diagnosi di NU.Gli autori descrivono le caratteristiche audiologiche ed eziologiche legate a suddetti pazienti paragonando l’incidenza della neuropatia uditiva in UTIN, il grado della sordità, la mono-bilateralità, i fattori di rischio e l’iter riabilitativo più idoneo con i dati riportati in letteratura. CONCLUSIONI La neuropatia uditiva, essendo causa di ipoacusia, può compromettere lo sviluppo del linguaggio e necessita di una diagnosi tempestiva per poter adottare le opportune misure riabilitative. In considerazione della necessità di esecuzione contemporanea di OAEs e dell’ABR ai fini di una corretta diagnosi, oltre che dei costi associati a quest’ultima metodica si raccomanda la valutazione dei potenziali evocati uditivi nei neonati ricoverati in UTIN e nei soggetti esposti a fattori di rischio più frequentemente associati a NU

Epidemiologia, aspetti genetici e clinici nei neonati con familiarità per ipoacusia: esperienza di un centro di terzo livello

INTRODUZIONE Rilievo frequente nei soggetti affetti da ipoacusia neurosensoriale (SNHL) è un' anamnesi familiare positiva per sordità, correlata a mutazioni genetiche, non sempre facilmente individuate, responsabili del deficit uditivo. L'eziologia genetica costituisce complessivamente il 50-60% di tutte le cause di sordità. Si distinguono forme sindromiche e non sindromiche, queste ultime classificabili secondo le differenti modalità di trasmissione. Nel 50-80% dei casi è riscontrabile una mutazione interessante il gene della connessina 26 (GJB2) localizzato sul cromosoma 13 che oramai è noto, codifica per una proteina chiamata in causa nei processi di trasduzione dello stimolo sonoro. La medesima funzione appare essere svolta dalla connessina 30 (GJB6), e dalla connessina 31 (GJB3). Nei soggetti con ipoacusia di origine genetica si osserva un'ampia variabilit¨¤ nel profilo audiologico e nel decorso clinico in relazione ai geni coinvolti e al tipo di mutazione. Infatti è riscontrabile una perdita uditiva di grado variabile dal moderato al profondo, presente già alla nascita o insorta in epoche successive, a progressione clinica variabile. MATERIALI E METODI Il ruolo di primo piano che rivestono i fattori genetici nello sviluppo di ipoacusia si evince dai risultati relativi alla nostra casistica, costituita da 412 bambini (con età al momento della diagnosi compresa tra 1 e 6 mesi) esposti a fattori di rischio per SNHL in epoca prenatale e perinatale. RISULTATI In 41 casi (9,95% della popolazione in esame) è stata identificata una storia familiare di ipoacusia e tra questi, in 15 soggetti (36,7%) è stata evidenziata una perdita uditiva. L'analisi statistica ha rilevato una differenza significativa tra i soggetti esposti e non esposti a tale fattore (x2=28,56 e p<0,0001) confermando quanto già descrtitto in letteratura ossia che la una storia familiare di ipoacusia costituisce di per se un fattore di rischio indipendente per sordità. La perdita uditiva è risultata essere nel 100% dei casi di tipo neurosensoriale ed a sede cocleare, prevalentemente di grado profondo (con un valore medio di 100,69¡À16.46 dB HL), interessante entrambi gli orecchi (93.33%). Tutti i soggetti identificati come sordi sono stati sottoposti ad indagine genetica ed in alcuni casi è stato possibile, risalire alle mutazioni responsabili di tale quadro patologico (prevalentemente a carico del gene GJB2). CONCLUSIONI Considerata l'elevata incidenza, il ruolo che svolge tra i fattori di rischio nel determinismo della sordità, la frequente gravità del deficit uditivo ad essa associato, la familiarità necessita di una particolare attenzione mediante un'accurata anamnesi e un counselling genetico finalizzato a riconoscere precocemente tale condizione e l'eventuale ipoacusia ad essa associata. Ciò consente,soprattutto nelle forme ad insorgenza preverbale, l'attuazione di quei presidi riabilitativi e quindi un corretto sviluppo linguistico, cognitivo e, in definitiva, sociale del bambino

Bend but don’t break: a case study on the cultural entrepreneurial process in the publishing industry

Research on cultural industries has attracted considerable interest on cultural entrepreneurs as agents in complex interaction with multiple and evolving contexts. The study aims to capture the complexity and intensity of these relationships, exploring entrepreneurship as a journey driven by cultural and social dynamics on one side, and economic needs on the other. The investigation is an inductive inquiry carried out through an in-depth analysis of a single revelatory case in the publishing industry. Focusing on the relational process through which the entrepreneur and the context are co-created, the paper analyzes the entrepreneurial journey through the identification of three major stages: Divergence, Identity construction, and Institutionalization

Residues at the tip of the pore loop of NR3B-containing NMDA receptors determine Ca2+ permeability and Mg2+ block

<p>Abstract</p> <p>Background</p> <p>Members of the complex N-methyl-D-aspartate receptor (NMDAR) subfamily of ionotropic glutamate receptors (iGluRs) conventionally assemble from NR1 and NR2 subunits, the composition of which determines receptor properties. Hallmark features of conventional NMDARs include the requirement for a coagonist, voltage-dependent block by Mg²⁺, and high permeability for Ca²⁺. Both Mg²⁺sensitivity and Ca²⁺permeability are critically dependent on the amino acids at the N and N+1 positions of NR1 and NR2. The recently discovered NR3 subunits feature an unprecedented glycine-arginine combination at those critical sites within the pore. Diheteromers assembled from NR1 and NR3 are not blocked by Mg²⁺and are not permeable for Ca²⁺.</p> <p>Results</p> <p>Employing site-directed mutagenesis of receptor subunits, electrophysiological characterization of mutants in a heterologous expression system, and molecular modeling of the NMDAR pore region, we have investigated the contribution of the unusual NR3 N and N+1 site residues to the unique functional characteristics of receptors containing these subunits. Contrary to previous studies, we provide evidence that both the NR3 N and N+1 site amino acids are critically involved in mediating the unique pore properties. Ca²⁺permeability could be rescued by mutating the NR3 N site glycine to the NR1-like asparagine. Voltage-dependent Mg²⁺block could be established by providing an Mg²⁺coordination site at either the NR3 N or N+1 positions. Conversely, "conventional" receptors assembled from NR1 and NR2 could be made Mg²⁺insensitive and Ca²⁺impermeable by equipping either subunit with the NR3-like glycine at their N positions, with a stronger contribution of the NR1 subunit.</p> <p>Conclusions</p> <p>This study sheds light on the structure-function relationship of the least characterized member of the NMDAR subfamily. Contrary to previous reports, we provide evidence for a critical functional involvement of the NR3 N and N+1 site amino acids, and propose them to be the essential determinants for the unique pore properties mediated by this subunit.</p

BEND BUT DON’T BREAK: A CASE STUDY ON THE CO-CREATING STRATEGY OF A CULTURAL ENTREPRENEURIAL PROCESS

Cultural entrepreneurship dynamics have attracted considerable interest of management scholars in the last years. Research in this field has so far focused the level of analysis on the cultural entrepreneur as individual or network agency, without extensively examining a broader concept of collective agency. By investigating the case study of a three-dimensional entrepreneur in the field of the publishing industry that acts as a bookseller, as an independent publisher and as a cultural mediator, the study explores the actual possibilities of cultural entrepreneurship. We developed content analysis of three corpora of documents, tracing the evolving of the narratives in the entrepreneurial journey. Our findings position the cultural entrepreneurship on the level of a recursive collective co- creation narrative between the entrepreneur himself and different stakeholders over time. In a journey of continuous experimentation, the cultural entrepreneur evolves to a cultural mediator, in order to overcome the duality between his cultural and economic aspirations through the immersion in the social context where he works and through the use of the book as a cultural and social artifact

REBALANCING DISRUPTIVE BUSINESS OF MULTINATIONAL CORPORATIONS AND GLOBAL VALUE CHAINS WITHIN DEMOCRATIC AND INCLUSIVE CITIZENSHIP PROCESSES- REVIEW WORKING PAPER

The purpose of this working paper is to conduct a comprehensive review of existing literature that explores the relationship between business organizations and democracy. This review draws from various fields, including management, business ethics, sociology, international law, and other relevant disciplines for this Project and has several objectives. Firstly, it aims to provide insight into prior research on how democratic institutions regulate economic actors and how these actors, particularly large multinational corporations (MNCs), resist such regulation. Additionally, it examines how these economic actors develop behaviors and economic models that pose challenges to democratic governance, such as business-related human rights violations. In the initial part of the review, we delve into the historical and contemporary aspects of the relationship between business and democracy. Furthermore, the report explores how companies can contribute to shaping a more democratic future by addressing gaps in governance, especially in cases where populist governments fail to protect the rights of their citizens. It also considers the development of alternative business models, such as social enterprises and cross-sector partnerships. Moreover, it looks into how businesses can actively engage in democratic governance and promote principles of participation. The final section of the working paper involves a bibliometric analysis, including co authorship, co-citation, and keyword co-occurrence maps. This analysis is based on key references used by team members in their literature reviews and is designed to examine the connections that exist among various strands of research that support the research questions of the Rebalance Project

The genome of the emerging barley pathogen Ramularia collo-cygni

Background Ramularia collo-cygni is a newly important, foliar fungal pathogen of barley that causes the disease Ramularia leaf spot. The fungus exhibits a prolonged endophytic growth stage before switching life habit to become an aggressive, necrotrophic pathogen that causes significant losses to green leaf area and hence grain yield and quality. Results The R. collo-cygni genome was sequenced using a combination of Illumina and Roche 454 technologies. The draft assembly of 30.3 Mb contained 11,617 predicted gene models. Our phylogenomic analysis confirmed the classification of this ascomycete fungus within the family Mycosphaerellaceae, order Capnodiales of the class Dothideomycetes. A predicted secretome comprising 1053 proteins included redox-related enzymes and carbohydrate-modifying enzymes and proteases. The relative paucity of plant cell wall degrading enzyme genes may be associated with the stealth pathogenesis characteristic of plant pathogens from the Mycosphaerellaceae. A large number of genes associated with secondary metabolite production, including homologs of toxin biosynthesis genes found in other Dothideomycete plant pathogens, were identified. Conclusions The genome sequence of R. collo-cygni provides a framework for understanding the genetic basis of pathogenesis in this important emerging pathogen. The reduced complement of carbohydrate-degrading enzyme genes is likely to reflect a strategy to avoid detection by host defences during its prolonged asymptomatic growth. Of particular interest will be the analysis of R. collo-cygni gene expression during interactions with the host barley, to understand what triggers this fungus to switch from being a benign endophyte to an aggressive necrotroph

Distinct pharmacological and functional properties of NMDA receptors in mouse cortical astrocytes

Background and purpose Astrocytes of the mouse neocortex express functional NMDA receptors which are not blocked by Mg2+ions. However, study of the pharmacological profile of glial NMDARs and their subunit composition is far from complete. Experimental approach In the present study we tested the sensitivity of NMDA receptor-mediated currents in the cortical astrocytes and neurons to the novel GluN2C/D subunit-selective antagonist UBP141. We also examined the action of memantine, an antagonist reported to have substantially different affinities for GluN2A/B and GluN2C/D-containing receptors in physiological concentrations of extracellular Mg2+ . Key results UBP141 had a strong inhibitory action on NMDA receptor-mediated transmembrane currents in the cortical layer II/III astrocytes with an IC50 of 2.29 μM and a modest inhibitory action on NMDA-responses in the pyramidal neurons with IC50 of 19.8 μM. Astroglial and neuronal NMDA receptors exhibited different sensitivities to memantine with corresponding IC50 of 2.19 and 10.8 μM, respectively. Consistent with pharmacological differences between astroglial and neuronal NMDA receptors, NMDA receptors in astrocytes showed lower Ca2+-permeability than neuronal ones with PCa/PNa ratio of 3.4. Conclusions and Implications The combination of biophysical and pharmacological properties of astrocytic NMDA receptors strongly suggests they have tri-heteromeric structure composed of GluN1, GluN2C/D and GluN3 subunits. Dramatic difference between astroglial and neuronal NMDA receptors in their sensitivity to UBP141 and memantine may enable selective modulation of astrocytic signalling that could be very helpful for elucidating the mechanisms of neuron-glia communications. Our results may also provide a clue for development novel therapeutic agents specifically targeting glial signalling

Creative Work and Entrepreneurial Creativity

Questions of how entrepreneurs exploit opportunities to create value are a big part of the discourse on creative work in contemporary societies (Alvarez et al., 2013). Entrepreneurs often build their creative journey by forming social bonds of opportunities (Daskalaki, 2010) that are meant to help creative work, but also constitute challenges to creative freedom (Montanari et al., 2016). This second aspect is not explored enough in studies on entrepreneurial venturing (Lingo, 2020), and a deeper analysis of the ambivalence of relational bonds may foster a better understanding of today’s entrepreneurial creativity in practice. Does the construction of ties with different actors and motivations necessarily go in the same direction in terms of creativity or can they contrast? How is the contrast solved? These questions are significant as entrepreneurs often experience that financial bonds highly limit their creative work, and vice versa that creative work is played not totally taking into account economic concerns. This is particularly true for entrepreneurs in the CCIs for the dual nature of their work (Lampel et al., 2000), based on the balance between the production of cultural and symbolic meanings for society (Jones &amp; Townley, 2016) and economic wealth (Lounsbury &amp; Glynn, 2001). Among those, small and micro cultural entrepreneurs are exposed to higher uncertainty than others, but they are also recognized as the most diffused and important drivers of European cultural variety, if in the last year they were conferred specific attention through resilience policies (as done in Italy for the independent publishing sector). We thus propose an inductive inquiry (Glaser &amp; Strauss, 1967) carried out through an in-depth analysis of a single revelatory case (Siggelkow, 2007; Yin, 2009), that well represents the ambivalence of the creative process of small entrepreneurs in the CCIs. Our multifaceted venture was born in the mainland of Venice in 2006 with the mission to become a cultural reality dedicated to narrative and theatrical languages for young audiences. Funded as a social cooperative by a group of artists, the company moved through a sequence of changes where both its inner configuration and its external context were shaped by the dynamics of bonds and ties with a number of local actors, such as schools and universities, public and private institutions, and the 1 Corresponding author: Monica Calcagno, Ca’ Foscari University, Fondamenta S. Giobbe, Cannaregio 873, Venice, [email protected]. municipality of Venice. From time to time, these unstable bonds constituted opportunities for entrepreneurial creativity and financial sustainability, while at the same were perceived by the entrepreneur as new obstacles to overcome. As a result, the entrepreneurial journey was configured as a continuous process of transformation where the opportunity of today had become the obstacle of tomorrow, regenerating the urgency of the entrepreneurial venture as a process of dynamic search for new (un)stable positions