bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coatomer protein complex I is required for efficient secretion of dengue virus non-structural protein 1
Authors: Johnson Stephen M. , Centofanti Siena M. , Bracho Gustavo , Beard Michael R. , Carr Jillian M. , Eyre Nicholas S. 
Published: October 2024

ABSTRACTSecreted non-structural protein 1 (sNS1) is an important orthoflavivirus pathogenic factor that can induce vascular leakage; a key symptom of severe dengue disease. Given the role of sNS1 in dengue pathogenesis, defining the molecular mechanisms of NS1 secretion may contribute towards development of NS1-targeting antiviral therapies. To this end, we performed a customised membrane-trafficking siRNA screen to identify human host factors involved in NS1 secretion. Our screen identified COPA, COPB2, and COPG1 as the top-ranking hits. These proteins are three of the seven subunits of the coatomer protein complex I (COPI) that coat transport vesicles that operate within the early secretory pathway, implicating COPI machinery as being involved in NS1 secretion. Validation studies employing host gene knockdown in dengue virus (DENV)-infected cells confirmed that COPI components are required for efficient NS1 secretion but are dispensable for infectious virus egress. Similar reductions in NS1 secretion were observed when COPI components were depleted in cells infected with West Nile virus Kunjin subtype (WNV/KUNV), indicating that the molecular mechanisms exploited to achieve NS1 secretion may be a conserved feature within the Orthoflavivirus genus. Heterologous expression of wildtype and pathogenic COPI variants in DENV NS1-NS5 polyprotein expressing cells resulted in altered NS1 secretion profiles, suggesting that allelic variants and altered expression levels of COPI components may indirectly influence the severity of dengue disease. The identification of COPI components as important determinants of NS1 secretion efficiency may aid in the identification of novel targets for anti-orthoflaviviral therapies.IMPORTANCEOver half of the world’s population is at risk of infection with mosquito-borne pathogenic orthoflaviviruses such as DENV. Although the secreted form of the viral NS1 protein has been identified as a major determinant of the pathogenic effects of DENV and related orthoflaviviruses, the exact mechanisms involved in NS1 secretion are poorly understood. Here we interrogated host factors involved in secretion of NS1 from infected cells using a customised membrane trafficking siRNA screen. This revealed 3 components of the COPI complex that regulates vesicular transport in the early secretory pathway as important factors in NS1 secretion. The involvement of COPI components in NS1 secretion was further validated using wildtype DENV and WNV/KUNV infection, overexpression approaches and chemical inhibition studies. Together, this study demonstrates the importance of COPI machinery in NS1 secretion and suggests that exploitation of this machinery in NS1 secretion may represent a future target of antiviral drug development.
A preserved neural code for temporal order between memory formation and recall in the human medial temporal lobe
Authors: Khazali Mohammad Farhan , Brandt Armin , Reinacher Peter C. , Kahana Michael , Jacobs Joshua , Schulze-Bonhage Andreas , Kunz Lukas 
Published: October 2024

AbstractTemporal memory enables us to remember the temporal order of events happening in our life. The human medial temporal lobe (MTL) appears to contain neural representations supporting temporal memory formation, but the cellular mechanisms that preserve temporal order information for recall are largely unknown. Here, we examined whether human MTL neuronal activity represents the temporal position of events during memory formation and recall, using invasive single and multi-unit recordings in human epilepsy patients (n = 19). Participants freely navigated a virtual environment in order to explore and remember locations and temporal positions of objects. During each exploration period, they sequentially encountered two or three different objects, placed in different locations. This allowed us to examine single- and multi-unit neuronal firing rates (FR) as a function of the temporal position the objects were presented in. We found that a significant number of multi-units and single-units in various MTL regions including the hippocampus showed selectivity to the temporal position of objects during the exploration period. During recall, patients were asked to indicate which one of two objects from the same trial was found latter. Neural firing rates during recall showed a selectivity supporting recall of temporal positions. Interestingly, most of the selective single-units that stayed selective during encoding and recall preserved their temporal position preference. Our results thus suggest that neuronal activity in the human MTL contains a preserved neural code for temporal order in memory formation and recall.
Region-specific spreading depolarization drives aberrant post-ictal behavior
Authors: Mitlasóczki Bence , Gómez Adrián Gutiérrez , Kamali Midia , Babushkina Natalia , Baues Mayan , Kück Laura , Haubrich André Nathan , Tamiolakis Theodoros , Breuer Annika , Granak Simon , Schwering-Sohnrey Merlin , Gerhauser Ingo , Baumgärtner Wolfgang , Ewell Laura , Opitz Thoralf , Pitsch Julika , Musall Simon , Surges Rainer , Mormann Florian , Beck Heinz , Wenzel Michael 
Published: October 2024

SummaryConfusion, aphasia, and unaware wandering are prominent post-ictal symptoms regularly observed in temporal lobe epilepsy (TLE)1. Despite the potentially life-threatening nature of the immediate post-ictal state2, its neurobiological underpinnings remain understudied3. We provide evidence in mice and humans that seizure-associated focal spreading depolarization (sSD) is a pathoclinical key factor in epilepsy. Using two-photon or widefield imaging (hippocampus, neocortex), field potential and single unit recordings, and behavioral assessment in mice, we first studied seizures during viral encephalitis, and subsequently established an optogenetic approach to dissociate hippocampal seizures and SD. We find region-specific occurrence of sSD that displays distinct spatial trajectories to preceding seizures, and show that seizure-related and isolated hippocampal SD promptpost-ictal wandering. This clinically relevant locomotor phenotype occurred in the absence of hippocampal SD progression to the neocortex. Finally, we confirm sSD existence in human epilepsy, in a patient cohort with refractory focal epilepsy, via Behnke-Fried electrode recordings. In this cohort, sSD displayed a similar temporomesial propensity as in mice. This work uncovers sSD as a previously underrecognized pathoclinical entity underlying postictal behavioral abnormalities in epilepsy. Our results carry wide-reaching ramifications for epilepsy research and neurology, and challenge current EEG-standards.
Perforation of the host cell plasma membrane duringToxoplasma gondiiinvasion requires rhoptry exocytosis
Authors: Male Frances , Kegawa Yuto , Blank Paul S. , Jiménez-Munguía Irene , Sidik Saima M. , Valleau Dylan , Lourido Sebastian , Lebrun Maryse , Zimmerberg Joshua , Ward Gary E. 
Published: October 2024

AbstractToxoplasma gondiiis an obligate intracellular parasite, and the delivery of effector proteins from the parasite into the host cell during invasion is critical for invasion itself and for parasite virulence. The effector proteins are released from specialized apical secretory organelles known as rhoptries. While much has been learned recently about the structure and composition of the rhoptry exocytic machinery and the function of individual rhoptry effector proteins that are exocytosed, virtually nothing is known about how the released proteins are translocated across the host cell plasma membrane. Previous electrophysiology experiments reported an unanticipated observation that invasion byT. gondiiis preceded by a transient increase in host cell plasma membrane conductance. Here, we confirm this electrophysiological observation and propose that the conductance transient represents a parasite-induced perforation in the host cell plasma membrane through which rhoptry proteins are delivered. As a first step towards testing this hypothesis, and to provide higher throughput than patch clamp electrophysiology, we developed an alternative assay to detect the perforation. This assay utilizes high-speed, multi-wavelength fluorescence imaging to enable simultaneous visualization of host cell perforation and parasite invasion. Using this assay, we interrogated a panel of mutant parasites conditionally depleted of key invasion-related proteins. Parasites lacking signaling proteins involved in triggering rhoptry secretion (e.g., CLAMP) or components of the rhoptry exocytic machinery (e.g., Nd9, RASP2) are defective in their ability to induce the perforation. These data are consistent with a model in which the perforating agents that disrupt host cell membrane integrity during invasion – and may thereby provide the conduit for delivery of rhoptry effector proteins – are stored within the rhoptries themselves and released upon contact with the host cell.
A Small-molecule Antagonist Radiotracer for Positron Emission Tomography Imaging of the Mu Opioid Receptor
Authors: Plakas Konstantinos , Hsieh Chia-Ju , Guarino Dinahlee Saturnino , Hou Catherine , Chia Wai-Kit , Young Anthony , Schmitz Alexander , Ho Yi-Pei , Weng Chi-Chang , Lee Hsiaoju , Li Shihong , Graham Thomas J.A. , Mach Robert H. 
Published: October 2024

AbstractThe opioid crisis is a catastrophic health emergency catalyzed by the misuse of opioids that target and activate the mu opioid receptor. Traditional radioligands used to study the mu opioid receptor are often tightly regulated owing to their abuse and respiratory depression potential. In the present study, we sought to design and characterize a library of 24 non-agonist ligands for the mu opioid receptor. Ligands were evaluated for the binding affinity, intrinsic activity, and predicted blood-brain barrier permeability. Several ligands demonstrated single-digit nM binding affinity for the mu opioid receptor while also demonstrating selectivity over the delta and kappa opioid receptors. The antagonist behavior of1Aand3Aat the mu opioid receptor indicate that these ligands would likely not induce opioid-dependent respiratory depression. Therefore, these ligands can enable a safer means to interrogate the endogenous opioid system. Based on binding affinity, selectivity, and potential off-target binding, [11C]1Awas prepared via metallophotoredox of the aryl-bromide functional group to [11C]methyl iodide. The nascent radiotracer demonstrated brain uptake in a rhesus macaque model and accumulation in the caudate and putamen. Naloxone was able to reduce [11C]1Abinding, though the interactions were not as pronounced as naloxone’s ability to displace [11C]carfentanil. These results suggest that GSK1521498 and related congeners are amenable to radioligand design and can offer a safer way to query opioid neurobiology.
DNA polymerase η is regulated by mutually exclusive mono-ubiquitination and mono-NEDDylation
Authors: Moreno Natália Cestari , Korchak Emilie J. , Latancia Marcela Teatin , D’Orlando Dana A. , Adegbenro Temidayo , Bezsonova Irina , Woodgate Roger , Ashton Nicholas W. 
Published: October 2024

ABSTRACTDNA polymerase eta (Pol η) is a Y-family translesion polymerase responsible for synthesizing new DNA across UV-damaged templates. It is recruited to replication forks following mono-ubiquitination of the PCNA DNA clamp. This interaction is mediated by PCNA-interacting protein (PIP) motifs within Pol η, as well as by its C-terminal ubiquitin-binding zinc finger (UBZ) domain. Previous work has suggested that Pol η itself is mono-ubiquitinated at four C-terminal lysine residues, which is dependent on prior ubiquitin-binding by its UBZ domain. Here, we show that Pol η can be modified at the same lysine residues by the ubiquitin-like protein, NEDD8. Like ubiquitination, this modification is driven by non-covalent interactions between NEDD8 and the UBZ domain. While only a small proportion of Pol η is mono-NEDDylated under normal conditions, these levels rapidly increase by inhibiting the COP9 signalosome, suggesting that mono-NEDDylation is maintained under strong negative regulation. Finally, we provide data to support that mono-ubiquitination is important for Pol η foci formation and suggest that NEDDylation disrupts this process. These results reveal a new mechanism of Pol η regulation by ubiquitin-like proteins.
Synergistic Role of Amino Acids in Enhancing mTOR Activation Through Lysosome Positioning
Authors: Kolaczkowski Oralia M. , Goodson Baley A. , Montenegro Vazquez Valeria , Jia Jingyue , Qadir Bhat Aadil , Kim Tae-Hyung , Pu Jing 
Published: October 2024

AbstractLysosome positioning, or lysosome cellular distribution, is critical for lysosomal functions in response to both extracellular and intracellular cues. Amino acids, as essential nutrients, have been shown to promote lysosome movement toward the cell periphery. Peripheral lysosomes are involved in processes such as lysosomal exocytosis, cell migration, and metabolic signaling—functions that are particularly important for cancer cell motility and growth. However, the specific types of amino acids that regulate lysosome positioning, their underlying mechanisms, and their connection to amino acid-regulated metabolic signaling remain poorly understood. In this study, we developed a high-content imaging system for unbiased, quantitative analysis of lysosome positioning. We examined the 15 amino acids present in cell culture media and found that 10 promoted lysosome redistribution toward the cell periphery to varying extents, with aromatic amino acids showing the strongest effect. This redistribution was mediated by promoting outward transport through SLC38A9-BORC-kinesin 1/3 axis and simultaneously reducing inward transport via inhibiting the recruitment of Rab7 and JIP4 onto lysosomes. When examining the effects of amino acids on mTOR activation—a central regulator of cell metabolism—we found that the amino acids most strongly promoting lysosome dispersal, such as phenylalanine, did not activate mTOR on their own. However, combining phenylalanine with arginine, which activates mTOR without affecting lysosome positioning, synergistically enhanced mTOR activity. This synergy was lost when lysosomes failed to localize to the cell periphery, as observed in kinesin 1/3 knockout (KO) cells. Furthermore, breast cancer cells exhibited heightened sensitivity to phenylalanine-induced lysosome dispersal compared to noncancerous breast cells. Inhibition of LAT1, the amino acid transporter responsible for phenylalanine uptake, reduced peripheral lysosomes and impaired cancer cell migration and proliferation, highlighting the importance of lysosome positioning in these coordinated cellular activities. In summary, amino acid-regulated lysosome positioning and mTOR signaling depend on distinct sets of amino acids. Combining lysosome-dispersing amino acids with mTOR-activating amino acids synergistically enhances mTOR activation, which may be particularly relevant in cancer cells.
Entrepreneurial potential in digital transformation: scale development using item response theory
Authors: Prando Lidia Tiggemann , Schmitt Jeovani , Mendonça Anny Key de Souza , Rosa Fabrícia S. , Lunkes Rogério João , Bornia Antonio Cezar , Andrade Dalton Francisco de 
Published: October 2024

PurposeThis study aims to develop a scale using item response theory (IRT) to assess the entrepreneurial potential for digital transformation in Brazilian companies.Design/methodology/approachIRT was used to develop a scale for entrepreneurial potential in digital transformation. This scale was constructed from a questionnaire, covering the domains: (1) data-driven culture, (2) openness to knowledge and adaptation to change, (3) connectivity and (4) creativity and innovation. The questionnaire was administered to a sample of 216 entrepreneurs from small business enterprise (SBE) and startups in Brazil.FindingsA questionnaire was developed and validated to assess the latent trait of entrepreneurial potential within the context of digital transformation. Additionally, a three-level scale of entrepreneurial potential was established: low (level I), intermediate (level II) and high (level III). The interpretation of this scale provides valuable information on which domains, such as data-driven culture, innovation, among others, can be enhanced to improve the potential of entrepreneur for digital transformation.Research limitations/implicationsThe sample was limited to small Brazilian companies and startups, which may restrict the applicability of the results to other business or geographic contexts. Additionally, the items evaluated in the scale may not fully capture all nuances of entrepreneurial potential for digital transformation. Future research should consider including new items that cover a broader range of entrepreneurial characteristics.Practical implicationsThe findings of this study have significant practical implications for the Brazilian entrepreneurial ecosystem, the entrepreneurs themselves, public policy makers and entrepreneurship support institutions. These results can guide digital transformation strategies, adjustments in public policies and investments, thereby promoting economic development and innovation in the country.Originality/valueThis study stands out for using IRT as a robust methodology to develop an interpretative scale to assess entrepreneurial potential in the digital transformation era. By focusing on Brazilian SBEs and startups, the study offers an original contribution on how these companies are handling the challenges of digitalization and identifying areas for improvement to further promote digital transformation among entrepreneurs.
Impact of collective knowledge on individual research competence: exploring the mediating influence of knowledge management processes
Authors: Rani Shiva , Devi Elangbam Binodini 
Published: October 2024

PurposeThe purpose of the current study is to investigate the impact of collective knowledge on individual research competence. Further, the study investigates the mediation effect of the knowledge management process (KMP).Design/methodology/approachThe cross-sectional study adopts a quantitative conclusive research design. The study collects data specifically from academicians of Uttarakhand higher education institutions (HEIs). The study uses random sampling because the list of faculty members is uploaded on the website of the university portal. The author directly sends the questionnaire to the email of the respondents and uses social media platforms. For the data analysis, the study used SMART-PLS 4.0.FindingsThe findings of the study reveal that KM infrastructure (KMI) and KM strategy directly impact KMP. The study also reveals that the KMP significantly impacts individual research competence. The current study also finds partial mediation support among KMI, KMP and individual research competence, and between KM strategy, KMP and individual research competence.Research limitations/implicationsThe current study uses a cross-sectional research design, future studies may include the longitudinal design to measure the effect of KM elements on individual research competence. The current study includes the data from the Uttarakhand region only, and it is difficult to generalize the results specifically to other states.Practical implicationsThe study emphasizes the importance of KM system development, a supportive KMI and a balanced KM strategy in HEIs.Originality/value Investigating collective knowledge’s impact on individual research competence, this study unveils mediation in KMP. Future research can broaden horizons by using the model.
AR atmospherics and virtual social presence impacts on customer experience and customer engagement behaviours
Authors: Zeng Ni , Ryding Daniella , Vignali Gianpaolo , Pantano Eleonora 
Published: October 2024

PurposeFew studies have examined technology-enhanced atmospheres for strengthening customer experience and brand engagement in physical store settings. This study builds on the social presence theory to test for the first time the moderating effects of virtual social presence on customer responses, through AR adoption in-store. Our study aims to understand the impact of technology-enhanced in-store atmospherics (TEISAs) with emphasis on AR elements and virtual social presence on customer experience and engagement behaviours (CEBs) in luxury settings.Design/methodology/approachHypotheses are developed and a survey using 566 responses were collected using Qualtrics. T-tests, two-way ANOVA and structural equation modelling were used for analysis of CEBs. Moreover, using PLS-SEM, we test whether virtual social presence moderates this relationship in a cross-country context; Britain and China, two of the largest economies for luxury growth.FindingsThe findings demonstrate that TEISAs have a positive impact on emotion and perceived value, with virtual social presence moderating this relationship. The cross-cultural comparison results show that the impact of TEISAs on emotion and perceived value is stronger for British than for Chinese millennials.Originality/valueOur model is the first to incorporate technology into various store atmospherics, to employ virtual social presence as a new moderator, and to provide empirical evidence on the effects of AR on customer experience and CEBs in the real-time luxury retail environment. This study is also the first to consider virtual social presence on social media as a moderating variable.
The dynamic relationship between ASEAN+6 exchange rates and stock markets: application of the ARDL model
Authors: Chancharat Surachai , Suwannapak Suthasinee 
Published: October 2024

PurposeThis study investigates the short- and long-run relationship between stock prices and exchange rates in the Association of Southeast Asian Nations (ASEAN)+6 markets. In the short run, support is found for both the theory of a goods market where exchange rates influence stock returns and portfolio balance theory, where stock returns influence exchange rates.Design/methodology/approachThe co-integration approach of linear and nonlinear augmented autoregressive distributed lag (ARDL) models was applied to daily data from 2 January 2017 to 30 June 2023.FindingsThe findings provide evidence that the goods market theory is supported solely in Indonesia and Singapore, while the portfolio balance theory is supported for Australia, China, India and Malaysia.Practical implicationsPolicymakers and investors should seriously consider the importance of the study findings. The results show that all ASEAN+6 countries experience a short-term interaction between the two markets. This illustrates that exchange rates and stock price movements play vital roles in other markets. Stakeholders, particularly policymakers, should be aware of this critical relationship.Originality/valueThis is the first study to dynamically examine how the ASEAN+6 framework influences currency rates and stock markets.