bluuebunny/crossref_metadata_2025 huggingface dataset:
Low immunogenicity of malaria pre-erythrocytic stages can be overcome by vaccination
Authors: Müller Katja , Gibbins Matthew P. , Reyes-Sandoval Arturo , Hill Adrian V. S. , Draper Simon J. , Matuschewski Kai , Silvie Olivier , Hafalla Julius Clemence R.
Published: September 2020

Vaccine discovery and development critically depends on predictive assays, which prioritise protective antigens. Immunogenicity is considered one important criterion for progression of candidate vaccines to further clinical evaluation, including phase I/II trials. Here, we tested this assumption in an infection and vaccination model for malaria pre-erythrocytic stages. We engineeredPlasmodium bergheiparasites that harbour a well-characterised epitope for stimulation of CD8+ T cells either as an antigen in the circumsporozoite protein (CSP), the surface coat protein of extracellular sporozoites or in the upregulated in sporozoites 4 (UIS4), a major protein associated with the parasitophorous vacuole membrane (PVM) that surrounds the intracellular exo-erythrocytic forms (EEF). We show that the antigen origin results in profound differences in immunogenicity with a sporozoite antigen eliciting robust and superior antigen-specific CD8+ T cell responses, whilst an EEF antigen evokes poor responses. However, despite their contrasting immunogenic properties, both sporozoite and EEF antigens gain access to antigen presentation pathways in hepatocytes, as recognition and targeting by vaccine-induced, antigen-specific effector CD8+ T cells results in high levels of protection when targeting both antigens. Our study is the first demonstration that poor immunogenicity of EEF antigens does not preclude their susceptibility to antigen-specific CD8+ T cell killing. Our findings that antigen immunogenicity is an inadequate predictor of vaccine susceptibility have wide-ranging implications on antigen prioritisation for the design and testing of next-generation pre-erythrocytic malaria vaccines.
Evaluating Inositol phospholipid interactions with Inward Rectifier Potassium Channels and characterising their role in Disease
Authors: Pipatpolkai Tanadet , Corey Robin A. , Proks Peter , Ashcroft Frances M. , Stansfeld Phillip J.
Published: September 2020

Membrane proteins are frequently modulated by specific protein-lipid interactions. The activation of human inward rectifying potassium (hKir) channels by phosphoinositides (PI) has been well characterised. Here, we apply a coarse-grained molecular dynamics free-energy perturbation (CG-FEP) protocol to capture the energetics of binding of PI lipids to hKir channels. By using either a single- or multi-step approach, we establish a consistent value for the binding of PIP2to hKir channels, relative to the binding of the bulk phosphatidylcholine phospholipid. Furthermore, by perturbing amino acid side chains on hKir6.2, we show that the neonatal diabetes mutation E179K increases PIP2affinity, while the congenital hyperinsulinism mutation K67N results in a reduced affinity. We show good agreement with electrophysiological data where E179K exhibits a reduction in neomycin sensitivity, implying that PIP2binds more tightly E179K channels. This illustrates the application of CG-FEP to compare affinities between lipid species, and for annotating amino acid residues.
Structural characterization of LsrK to target quorum sensing and comparison between X-ray and homology model
Authors: Medarametla Prasanthi , Laitinen Tuomo , Poso Antti
Published: September 2020

Quorum sensing is being investigated as an alternative therapeutic strategy in antibacterial drug discovery to combat bacterial resistance. LsrK is an autoinducer-2 kinase, playing a key role in the phosphorylation of autoinducer-2 (AI-2) signalling molecules involved in quorum sensing. Inhibiting LsrK could result in reduced pathogenicity by interfering with the quorum sensing signalling. Previously, we have generated homology models to identify LsrK inhibitors using structure-based virtual screening and successfully found the first class of LsrK inhibitors. While conducting these studies, the crystal structure of LsrK was released providing us an opportunity to inspect the reliability and quality of our models. Structural analysis of crystal structure and homology models revealed the consistencies of constructed models with crystal structure in the structural fold and binding site. Further, binding characteristics and conformational changes are investigated using molecular dynamics. These simulations provided us insights into the protein function and flexibility that need to be considered during the structure-based drug design studies targeting LsrK.
Population stratification in GWAS meta-analysis should be standardized to the best available reference datasets
Authors: Sarmanova Aliya , Morris Tim , Lawson Daniel John
Published: September 2020

Population stratification has recently been demonstrated to bias genetic studies even in relatively homogeneous populations such as within the British Isles. A key component to correcting for stratification in genome-wide association studies (GWAS) is accurately identifying and controlling for the underlying structure present in the sample. Meta-analysis across cohorts is increasingly important for achieving very large sample sizes, but comes with the major disadvantage that each individual cohort corrects for different population stratification. Here we demonstrate that correcting for structure against an external reference adds significant value to meta-analysis. We treat the UK Biobank as a collection of smaller studies, each of which is geographically localised. We provide software to standardize an external dataset against a reference, provide the UK Biobank principal component loadings for this purpose, and demonstrate the value of this with an analysis of the geographically sampled ALSPAC cohort.
Local postsynaptic signalling on slow time scales in reciprocal olfactory bulb granule cell spines matches asynchronous release
Authors: Jodar Tiffany Ona , Lage-Rupprecht Vanessa , Abraham Nixon M. , Rose Christine R. , Egger Veronica
Published: September 2020

In the vertebrate olfactory bulb (OB), axonless granule cells (GC) mediate self- and lateral inhibitory interactions between mitral/tufted cells via reciprocal dendrodendritic synapses. Locally triggered release of GABA from the large reciprocal GC spines occurs on both fast and slow time scales, possibly enabling parallel processing during olfactory perception. Here we investigate local mechanisms for asynchronous spine output.

To reveal the temporal and spatial characteristics of postsynaptic ion transients, we imaged spine and adjacent dendrite Ca2+- and Na+-signals with minimal exogenous buffering by the respective fluorescent indicator dyes upon two-photon uncaging of DNI-glutamate in OB slices from juvenile rats. Both postsynaptic fluorescence signals decayed slowly, with average half durations in the spine head of t1/2_Δ[Ca2+]i~500 ms and t1/2_Δ[Na+]i~1000 ms. We also analysed the kinetics of already existing data of postsynaptic spine Ca2+-signals in response to glomerular stimulation in OB slices from adult mice, either WT or animals with partial GC glutamate receptor deletions (NMDAR: GluN1 subunit; AMPAR: GluA2 subunit). In a large subset of spines the fluorescence signal had a protracted rise time (average time to peak ~400 ms, range 20 ms - >1000 ms). This slow rise was independent of Ca2+entry via NMDARs, since similarly slow signals occurred in ΔGluN1 GCs. Additional Ca2+entry in ΔGluA2 GCs (with AMPARs rendered Ca2+-permeable), however, resulted in larger ΔF/Fs that rose yet more slowly.

Thus GC spines appear to dispose of several local mechanisms to promote asynchronous GABA release, which are reflected in the time course of mitral/tufted cell recurrent inhibition.
Twinfilin1 controls lamellipodial protrusive activity and actin turnover during vertebrate gastrulation
Authors: Devitt Caitlin C. , Lee Chanjae , Cox Rachael M. , Papoulas Ophelia , Alvarado José , Marcotte Edward M. , Wallingford John B.
Published: September 2020

The dynamic control of the actin cytoskeleton is a key aspect of essentially all animal cell movements. Experiments in single migrating cells andin vitrosystems have provided an exceptionally deep understanding of actin dynamics. However, we still know relatively little of how these systems are tuned in cell-type specific ways, for example in the context of collective cell movements that sculpt the early embryo. Here, we provide an analysis of the actin severing and depolymerization machinery during vertebrate gastrulation, with a focus on Twinfilin1. We confirm previous results on the role of Twf1 in lamellipodia and extend those findings by linking Twf1, actin turnover, and cell polarization required for convergent extension during vertebrate gastrulation.
The p97-UBXN1 complex regulates aggresome formation
Authors: Mukkavalli Sirisha , Klickstein Jacob Aaron , Ortiz Betty , Juo Peter , Raman Malavika
Published: September 2020

The recognition and disposal of misfolded proteins are essential for the maintenance of cellular homeostasis. Perturbations in the pathways that promote degradation of aberrant proteins contribute to a variety of protein aggregation disorders broadly termed proteinopathies. It is presently unclear how diverse disease-relevant aggregates are recognized and processed for degradation. The p97 AAA-ATPase in combination with a host of adaptor proteins functions to identify ubiquitylated proteins and target them for degradation by the ubiquitin-proteasome system or through autophagy. Mutations in p97 cause multi-system proteinopathies; however, the precise defects underlying these disorders are unclear given the large number of pathways that rely on p97 function. Here, we systematically investigate the role of p97 and its adaptors in the process of formation of aggresomes which are membrane-less structures containing ubiquitylated proteins that arise upon proteasome inhibition. We demonstrate that p97 mediates both aggresome formation and clearance in proteasome-inhibited cells. We identify a novel and specific role for the p97 adaptor UBXN1 in the process of aggresome formation. UBXN1 is recruited to ubiquitin-positive aggresomes and UBXN1 knockout cells are unable to form a single aggresome, and instead display dispersed ubiquitin aggregates. Furthermore, loss of p97-UBXN1 results in the increase in Huntingtin polyQ aggregates both in mammalian cells as well as in aC.elegansmodel of Huntington’s Disease. Together our work identifies evolutionarily conserved roles for p97 and its adaptor UBXN1 in the disposal of protein aggregates.
The impact of stomatal kinetics on diurnal photosynthesis and water use efficiency under fluctuating light
Authors: Eyland David , van Wesemael Jelle , Lawson Tracy , Carpentier Sebastien
Published: September 2020

Dynamic light conditions require continuous adjustments of stomatal aperture. As stomatal conductance (gs) kinetics are a magnitude slower than photosynthesis (A), they are hypothesized to be key to plant productivity and water use efficiency. Using step-changes in light intensity, we studied the diversity of light-induced gskinetics in relation to stomatal anatomy in five banana genotypes (Musaspp.) and modelled the impact onAand intrinsic water use efficiency (iWUE). Banana generally exhibited a strong limitation ofAby gs, indicating a priority for water saving. Significant genotypic differences in gskinetics and gs-based limitations ofAwere observed. For two contrasting genotypes the impact of differential gskinetics onAandiWUE was further investigated under realistic diurnally fluctuating light conditions and at whole-plant level. Genotype-specific stomatal kinetics observed at the leaf level were corroborated at whole-plant level, suggesting that despite differences in gscontrol at different locations in the leaf and across leaves, genotype-specific responses are still maintained. However, under diurnally fluctuating light conditions gsspeediness had only a momentary impact on the diurnaliWUE and carbon gain. During the afternoon there was a setback in kinetics: the absolute gsand the gsresponses to light were damped, strongly limitingAand the diurnaliWUE. We conclude that the impact of the differential gskinetics on the limitation ofAwas dependent on the target light intensity, the magnitude of change, the gsprior to the intensity change and particularly the time of the day.

One sentence summary

Genotype-specific stomatal rapidity is for the first time validated at whole-plant level, but under fluctuating light the impact of stomatal dynamics depends on other factors like the time of the day.
Dendritic localization of mRNA inDrosophilaMushroom Body Output Neurons
Authors: Mitchell Jessica , Smith Carlas S. , Titlow Josh , Otto Nils , van Velde Pieter , Booth Martin , Davis Ilan , Waddell Scott
Published: September 2020

Memory-relevant neuronal plasticity is believed to require local translation of new proteins at synapses. Understanding this process requires the visualization of the relevant mRNAs within these neuronal compartments. Here we used single-molecule fluorescencein situhybridization (smFISH) to localize mRNAs at subcellular resolution in the adultDrosophilabrain. mRNAs for subunits of nicotinic acetylcholine receptors and kinases could be detected within the dendrites of co-labelled Mushroom Body Output Neurons (MBONs) and their relative abundance showed cell-specificity. Moreover, aversive olfactory learning produced a transient increase in the level ofCaMKIImRNA within the dendritic compartments of the γ5β′2a MBONs. Localization of specific mRNAs in MBONs before and after learning represents a critical step towards deciphering the role of dendritic translation in the neuronal plasticity underlying behavioural change inDrosophila.
Biomechanical Modeling of a Bone Tunnel Enlargement Post ACL Reconstruction
Authors: Borjali Amirhossein , Mohseni Mahdi , Chizari Mahmoud
Published: September 2020

Background

Bone tunnel enlargement is considered as a potential problem following ACL reconstruction and can cause a fixation failure and complicate its revision surgery. This study evaluates post tibial tunnel expansion in ACL reconstruction using an interference screw.

Methods

A series of in-vitro experimental tests on animal bone and tissues were used to simulate post ACL reconstruction. The study believes an unbalanced lateral force can cause a local enlargement on the contact zone inside the tunnel. Grayscale X-ray images were used to assess the screw alignment inside the tunnel.

Results

They showed a slight misalignment between the screw and the tunnel axis as the tendon strands moved along the side of the tunnel, and the screw had partial contact with the tendon and bone along the tunnel. According to the results, increased stress in the tunnel wall causes tunnel enlargement. Although the tunnel created away from the tibial central axis produced a higher strength, it results in higher stress on the wall of the tunnel which can increase the risk of tunnel expansion.

Conclusions

The current study believes the use of an unguided interference screw insertion potentially increases risks of the misaligned fixation and cause a tunnel enlargement. This risk may be controlled by restricting the post-operative rehabilitation.
Redundancy Circuits of the Commissural Pathways in Human and Rhesus Macaque Brains
Authors: Ghulam-Jelani Zulfar , Barrios-Martinez Jessica , Eguiluz-Melendez Aldo , Gomez Ricardo , Anania Yury , Yeh Fang-Cheng
Published: September 2020

It has been hypothesized that the human brain has traded redundancy for efficiency, but the structural existence has not been identified to examine this claim. Here, we report three redundancy circuits of the commissural pathways in primate brains, namely the orbitofrontal, temporal, and occipital redundancy circuits of the anterior commissure and corpus callosum. Each redundancy circuit has two distinctly separated routes connecting a common pair of cortical regions. We mapped their trajectories in human and rhesus macaque brains using individual and population-averaged tractography. The dissection results confirmed the existence of these redundancy circuits connecting the orbitofrontal lobe, amygdala, and visual cortex. The volume analysis showed a significant reduction in the orbitofrontal and occipital redundancy circuits of the human brain, whereas the temporal redundancy circuit had a substantial organizational difference between the human and rhesus macaque. Our overall findings suggest that the human brain is more efficient in the commissural pathway, as shown by the significantly reduced volume of the anterior commissure which serves as the backup connections for the corpus callosum. This reduction of the redundancy circuit may explain why humans are more vulnerable to psychiatric brain disorders stemming from the corpus callosum compared to non-human primates.

Significance

We report and describe the connection routes of three redundancy circuits of the commissural pathways in human and rhesus macaque brains and compare their volumes. Our tractography and dissection studies confirmed that the human brain has smaller redundancy circuits. This is the first time such redundancy circuits of the commissural pathways have been identified, and their differences quantified in human and rhesus macaque to verify the redundancy-efficiency tradeoff hypothesis. The findings provide new insight into the topological organization of the human brain and may help understand the circuit mechanism of brain disorders involving these pathways.
HPM Live μ for a full CLEM workflow
Authors: Heiligenstein Xavier , de Beer Marit , Heiligenstein Jérôme , Eyraud Frédérique , Manet Laurent , Schmitt Fabrice , Lamers Edwin , Lindenau Joerg , Lindert Mariska Kea-te , Salamero Jean , Raposo Graça , Sommerdijk Nico , Belle Martin , Akiva Anat
Published: September 2020

With the development of advanced imaging methods that took place in the last decade, the spatial correlation of microscopic and spectroscopic information - known as multimodal imaging or correlative microscopy (CM) - has become a broadly applied technique to explore biological and biomedical materials at different length scales. Among the many different combinations of techniques, Correlative Light and Electron Microscopy (CLEM) has become the flagship of this revolution.

Where light (mainly fluorescence) microscopy can be used directly for the live imaging of cells and tissues, for almost all applications, electron microscopy (EM) requires fixation of the biological materials. Although sample preparation for EM is traditionally done by chemical fixation and embedding in a resin, rapid cryogenic fixation (vitrification) has become a popular way to avoid the formation of artefacts related to the chemical fixation/embedding procedures. During vitrification, the water in the sample transforms into an amorphous ice, keeping the ultrastructure of the biological sample as close as possible to the native state. One immediate benefit of this cryo-arrest is the preservation of protein fluorescence, allowing multi-step multi-modal imaging techniques for CLEM.

To further explore the potential of cryo-fixation, we developed a high-pressure freezing (HPF) system that allows vitrification under different environmental parameters and applied it in different CLEM workflows. In this chapter, we introduce our novel HPF live μ instrument with a focus on its coupling to a light microscope. We elaborate on the optimization of sample preservation and the time needed to capture a biological event, going from live imaging to cryo-arrest using HPF. We will address the adaptation of HPF to novel correlation workflows related to the forthcoming transition from imaging 2D (cell monolayers) to imaging 3D samples (tissue) and the associated importance of homogeneous deep vitrification. Lastly, we will discuss the potential of our HPM within CLEM protocols especially for correlating live imaging using the Zeiss LSM900 with electron microscopy.
Detecting local changes in chromatin architecture with false discovery control
Authors: Koch Hillary , Yang Tao , Imakaev Maxim , Hardison Ross C. , Li Qunhua
Published: September 2020

Hi-C experiments are a powerful means to describe the organization of chromatin interactions genome-wide. By using Hi-C data to identify differentially organized genomic regions, relationships between this organization, gene expression, and cell identity may be established. However, Hi-C data exhibit a unique and challenging spatial structure, as genomic loci can show strong correlations when they are nearby in 3D space within the nucleus or 1D space along the chromosome. Consequently, the development of methods that can accurately detect differences between Hi-C samples while controlling false discoveries has remained difficult. To meet this need, we introduce a spatial modeling approach based on sliding window statistics. Using polymer simulations, we illustrate the improved power and precision of our method to identify differentially interacting genomic regions. We further demonstrate our method’s ability to reveal biologically meaningful changes in chromatin architecture through two data analyses concerning the loss of architectural and chromatin remodeling proteins.
Selective Optogenetic Stimulation of Glutamatergic, but not GABAergic, Vestibular Nuclei Neurons Induces Immediate and Reversible Postural Imbalance in Mice
Authors: Montardy Q. , Wei M. , Yi T. , Liu X. , Zhou Z. , Lai J. , Besnard S. , Tighilet B. , Chabbert C. , Wang L.
Published: September 2020

Glutamatergic and GABAergic neurons represent the neural components of the medial vestibular nuclei. We assessed the functional role of glutamatergic and GABAergic neuronal pathways arising from the vestibular nuclei (VN) in the maintenance of gait and balance by optogenetically stimulating the VN in VGluT2-cre and GAD2-cre mice. We demonstrate that glutamatergic, but not GABAergic VN neuronal subpopulation is responsible for immediate and strong posturo-locomotor deficits, comparable to unilateral vestibular deafferentation models. During optogenetic stimulation, the support surface dramatically increased in VNVGluT2+mice, and rapidly fell back to baseline after stimulation, whilst it remained unchanged during similar stimulation of VNGAD2+mice. This effect persisted when vestibular compensation was removed. Posturo-locomotor alterations evoked in VNVGluT2+animals were still present immediately after stimulation, while they disappeared 1h later. Overall, these results indicate a fundamental role for VNVGluT2+neurons in balance and posturo-locomotor functions, but not for VNGAD2+neurons, in this specific context. This new optogenetic approach will be useful to characterize the role of the different VN neuronal populations involved in vestibular physiology and pathophysiology.

Highlights

For the first time, Vestibular nuclei were optogenetically stimulated in free-moving animals, to asses for glutamatergic and GABAergic neurons functions in posturo-locomotor behaviors.

Brief optogenetic activation of VNVGluT2+, but not VNGAD2+, induced immediate and strong postural deficit.

Stimulation of VNVGluT2+ neurons provoked an imbalance with continuous effect on locomotion for a short period of time after stimulation.

These results are comparable to the classical vestibular deafferentation models during their peak of deficit, and set optogenetic stimulation as a new model to study vestibular deficits.
Cytotoxic CD4 Development Requires CD4 Effectors to Concurrently Recognize Local Antigen and Encounter Infection-Induced IL-15
Authors: Devarajan Priyadharshini , Vong Allen M. , Castonguay Catherine H. , Silverstein Noah J. , Kugler-Umana Olivia , Bautista Bianca L. , Kelly Karen A. , Luban Jeremy , Swain Susan L.
Published: September 2020

Cytotoxic CD4 T cells (ThCTL) are tissue-resident effectors that enhance viral clearance by MHC-II-restricted cytotoxicity of infected cells. Using a model of influenza A virus (IAV) infection, we identify key factors that drive CD4 effectors to differentiate into lung-resident ThCTL. We find that, to become ThCTL, CD4 effectors must again recognize cognate antigen on antigen presenting cells (APC) within the lung. Different APC subsets can drive this transition, including dendritic cells, B cells, and to a lesser extent non-hematopoietic MHC-II+APC. CD28 co-stimulation is not required and can reduce ThCTL development. In contrast, T follicular helper cells (TFH) that are another specialized CD4 effector subset, require CD28 during this time. Optimal ThCTL generation also requires ongoing infection in the effector phase, that acts independently of antigen presentation. The mechanism involves production of Type I IFN, that induces IL-15 which acts to support further differentiation of CD4 effectors to ThCTL. The multiple spatial, temporal and cellular requirements for ThCTL generation from CD4 effectors described here would be expected to prevent cytotoxic CD4 responses in the lung after pathogen has already been cleared, while ensuring the development of potent lung-restricted ThCTL effectors when pathogen persists.
Inherently confinable split-drive systems inDrosophila
Authors: Terradas Gerard , Buchman Anna B. , Bennett Jared B. , Shriner Isaiah , Marshall John M. , Akbari Omar S. , Bier Ethan
Published: September 2020

CRISPR-based gene drive systems, which copy themselves based on gene conversion mediated by the homology directed repair (HDR) pathway, have potential to revolutionize vector control. However, mutant alleles generated by the competing non-homologous end-joining (NHEJ) pathway that are rendered resistant to Cas9 cleavage can interrupt the spread of genedrive elements. We hypothesized that drives targeting genes essential for viability or reproduction also carrying recoded sequences to restore endogenous gene functionality should benefit from dominantly-acting maternal clearance of NHEJ alleles, combined with recessive Mendelian processes. Here, we test split gene-drive (sGD) systems inDrosophila melanogasterthat were inserted into essential genes required for viability (rab5, rab11, prosalpha2) or fertility (spo11). In single generation crosses, sGDs copy with variable efficiencies and display sex-biased transmission. In multi-generational cage trials, sGD follow distinct drive trajectories reflecting their differential tendencies to induce target chromosome damage or lethal/sterile mosaic phenotypes, leading to inherently confineable drive outcomes.
Role of Epigenetics in Unicellular to Multicellular Transition inDictyostelium
Authors: Wang Simon Yuan , Pollina Elizabeth Ann , Wang I-Hao , Bushnell Henry L. , Takashima Ken , Fritsche Colette , Sabin George , Greer Paul Lieberman , Greer Eric Lieberman
Published: September 2020

The evolution of multicellularity is a critical event that remains incompletely understood. We use the social amoeba,Dictyostelium discoideum,one of the rare organisms that exists in both unicellular and multicellular stages, to examine the role of epigenetics in regulating multicellularity. While transitioning to multicellular states, patterns of H3K4 methylation and H3K27 acetylation significantly change. By combining transcriptomics, epigenomics, chromatin accessibility, and syntenic analyses with other unicellular and multicellular organisms, we identify 52 conserved genes, which are specifically accessible and expressed during multicellular states. We validated that four of these genes, including the H3K27 deacetylasehdaD,are necessary and that an SMC-like gene,smcl1,is sufficient for multicellularity. These results highlight the importance of epigenetics in reorganizing chromatin architecture to facilitate the evolution of multicellularity.

One Sentence Summary

Epigenetic regulation of multicellularity
Transcriptome analysis of a protein-truncating mutation insortilin-related receptor 1associated with early-onset familial Alzheimer’s disease indicates effects on mitochondrial and ribosome function in young-adult zebrafish brains
Authors: Barthelson Karissa , Pederson Stephen , Newman Morgan , Lardelli Michael
Published: September 2020

The early cellular stresses which eventually lead to Alzheimer’s disease (AD) remain poorly understood because we cannot access living, asymptomatic human AD brains for detailed molecular analyses. Sortilin-related receptor 1 (SORL1) encodes a multi-domain receptor protein genetically associated with both rare, early-onset familial AD (EOfAD) and common, sporadic late-onset AD (LOAD). SORL1 has been shown to play a role in the trafficking of the amyloid β A4 precursor protein (APP) which is cleaved proteolytically to form one of the pathological hallmarks of AD, amyloid β (Aβ) peptide. However, the other functions of SORL1 are less well understood. Here, we employed a reverse genetics approach to characterise the effect of an EOfAD mutation inSORL1using zebrafish as a model organism. We performed targeted mutagenesis to generate an EOfAD-like mutation in the zebrafish orthologue ofSORL1, and performed RNA-sequencing on mRNA isolated from a family of fish either heterozygous for the EOfAD-like mutation or their wild type siblings and identified subtle effects on the expression of genes which likely indicate changes in mitochondrial and ribosomal function. These changes appear to be independent of changes to expression of APP-related proteins in zebrafish, and mitochondrial content.
Retromer Combinatorials for Gene-Therapy Across a Spectrum of Neurological Diseases
Authors: Qureshi Yasir H. , Patel Vivek M. , Kannan Suvarnambiga , Waksal Samuel D , Petsko Gregory A. , Small Scott A.
Published: September 2020

Endosomal trafficking is a biological pathway implicated in Alzheimer’s and Parkinson’s disease, and a growing number of other neurological disorders. For this category of diseases, the endosome’s trafficking complex retromer has emerged as a validated therapeutic target. Retromer’s core is a heterotrimeric complex composed of the scaffold protein VPS35 to which VPS26 and VPS29 bind. Unless it is deficient, increasing expression of VPS35 by viral vectors has a limited effect on other trimeric members and on retromer’s overall function. Here we set out to address these constraints and, based on prior insight, hypothesized that co-expressing VPS35 and VPS26 would synergistically interact and elevate retromer’s trimeric expression and function. Neurons, however, are distinct in expressing two VPS26 paralogs, VPS26a and VPS26b, and so to test the hypothesis we generated three novel AAV9 vectors harboring the VPS35, or VPS26a, or VPS26b transgene. First, we optimized their expression in neuroblastoma cell lines, then, in a comprehensive series of neuronal culture experiments, we expressed VPS35, VPS26a, and VPS26b individually and in all possible combinations. Confirming our hypothesis, expressing individual proteins failed to affect the trimer, while VPS35 and VPS26 combinatorials synergized the trimer’s expression. In addition, we illustrate functional synergy by showing that only VPS35 and VPS26 combinatorials significantly increase levels of Sorl1, a key retromer-receptor deficient in Alzheimer’s disease. Collectively, and together with other recent observations, these results suggest a precision-medicine logic when applying retromer gene therapy to a host of neurological disorders, depending on each disorder’s specific retromer-related molecular and anatomical phenotype.
mTOR driven gene transcription is required for cholesterol production in neurons of the developing cerebral cortex
Authors: Schüle Martin , Butto Tamer , Dewi Sri , Schlichtholz Laura , Strand Susanne , Gerber Susanne , Endres Kristina , Schweiger Susann , Winter Jennifer
Published: September 2020

Dysregulated mammalian target of rapamycin (mTOR) activity is associated with various neurodevelopmental disorders ranging from idiopathic autism spectrum disorders to syndromes caused by single gene defects. This suggests that maintaining mTOR activity levels in a physiological range is essential for brain development and functioning. Upon activation, mTOR regulates a variety of cellular processes such as cell growth, autophagy and metabolism. On a molecular level, however, the consequences of mTOR activation in the brain are not well understood.

Low levels of cholesterol are associated with a wide variety of neurodevelopmental disorders. We here describe numerous genes of the sterol/cholesterol biosynthesis pathway to be transcriptionally regulated by mTOR complex 1 (mTORC1) signalingin vitroin primary neurons andin vivoin the developing cerebral cortex of the mouse. We find that these genes are shared targets of the transcription factors SREBP, SP1 and NF-Y. Prenatal as well as postnatal mTORC1 inhibition downregulated expression of these genes which directly translated into reduced cholesterol levels pointing towards a substantial metabolic function of the mTORC1 signaling cascade. Altogether, our results indicate that mTORC1 is an essential transcriptional regulator of the expression of sterol/cholesterol biosynthesis genes in the developing brain. Altered expression of these genes may be an important factor contributing to the pathogenesis of neurodevelopmental disorders associated with dysregulated mTOR signaling.
Shugoshin promotes efficient activation of spindle assembly checkpoint and timely spindle disassembly
Authors: Sane Aakanksha , Sridhar Shreyas , Sanyal Kaustuv , Ghosh Santanu K
Published: September 2020

Shugoshin proteins are evolutionary conserved across eukaryotes with some species-specific cellular functions ensuring the fidelity of chromosome segregation. Shugoshin being present at various subcellular locales, acts as an adaptor to mediate various protein-protein interactions in a spatio-temporal manner. Here, we characterize shugoshin (Sgo1) in the human fungal pathogen,Candida albicans. Interestingly, we discover a novelin vivolocalization of Sgo1 along the length of the mitotic spindle. Further, Sgo1 performs a hitherto unknown function of facilitating timely disassembly of spindle in this organism. We observe that Sgo1 retains its centromeric localization and performs its conserved functions that include regulating the centromeric condensin localization, chromosome passenger complex (CPC) maintenance and sister chromatid biorientation. We identify novel roles of Sgo1 as a spindle assembly checkpoint (SAC) component with functions in maintaining the SAC proteins, Mad2 and Bub1, at the kinetochores, in response to faulty kinetochore-microtubule attachments. These findings provide an excellent evidence of the functional rewiring of shugoshin in maintaining genomic stability.
Similarity of brain activity patterns during learning and subsequent resting state predicts memory consolidation
Authors: Zavecz Z. , Janacsek K. , Simor P. , Cohen M.X. , Nemeth D.
Published: September 2020

Long-term memory depends on memory consolidation that seems to rely on learning-induced changes in the brain activity. Here, we introduced a novel approach analyzing continuous EEG data to study learning-induced changes as well as trait-like characteristics in brain activity underlying consolidation. Thirty-one healthy young adults performed a learning task and their performance was retested after a short (~1h) delay, that enabled us to investigate the consolidation of serial-order and probability information simultaneously. EEG was recorded during a pre- and post-learning rest period and during learning. To investigate the brain activity associated with consolidation performance, we quantified similarities in EEG functional connectivity of learning and pre-learning rest (baseline similarity) as well as learning and post-learning rest (post-learning similarity). While comparable patterns of these two could indicate trait-like similarities, changes in similarity from baseline to post-learning could indicate learning-induced changes, possibly spontaneous reactivation. Individuals with higher learning-induced changes in alpha frequency connectivity (8.5–9.5 Hz) showed better consolidation of serial-order information. This effect was stronger for more distant channels, highlighting the role of long-range centro-parietal networks underlying the consolidation of serial-order information. The consolidation of probability information was associated with learning-induced changes in delta frequency connectivity (2.5–3 Hz) and seemed to be dependent on more local, short-range connections. Beyond these associations with learning-induced changes, we also found substantial overlap between the baseline and post-learning similarity and their associations with consolidation performance, indicating that stable (trait-like) differences in functional connectivity networks may also be crucial for memory consolidation.

Significance statement

We studied memory consolidation in humans by characterizing how similarity in neural oscillatory patterns during learning and rest periods supports consolidation. Previous studies on similarity focused on learning-induced changes (including reactivation) and neglected the stable individual characteristics that are present over resting periods and learning. Moreover, learning-induced changes are predominantly studied invasively in rodents or with neuroimaging or event-related electrophysiology techniques in humans. Here, we introduced a novel approach that enabled us 1) to reveal both learning-induced changes and trait-like individual differences in brain activity and 2) to study learning-induced changes in humans by analyzing continuous EEG. We investigated the consolidation of two types of information and revealed distinct learning-induced changes and trait-like characteristics underlying the different memory processes.
Development of modular school design as a permanent solution for post-disaster reconstruction in Indonesia
Authors: Yatmo Yandi Andri , Atmodiwirjo Paramita , Saginatari Diandra Pandu , Harahap Mochammad Mirza Yusuf
Published: September 2020

Purpose

This paper describes the development and implementation of a modular school building design prototype to support “build back better” after the disaster. The purpose of this paper is to bridge the gap between the two standard practices of post-disaster reconstruction: the quickly temporary construction and the permanent solution with longer time to complete.

Design/methodology/approach

The modular school design prototype was developed based on three design criteria established to achieve a relatively quick construction with good quality as a post-disaster permanent solution. The prototype was implemented in Kerandangan Village, Lombok and evaluated to review its compliance with the design criteria.

Findings

Three design strategies were proposed to respond to the main design criteria: the use of modular units and components, the material durability and availability, and the “plug-and-play” configuration system. Through these strategies, the prototype demonstrated the ability to perform as a permanent solution to be implemented in a short time. The prototype evaluation suggests some possible improvement to ensure a more efficient process and further replicability.

Originality/value

The development of the modular design bridges the gap between temporary and permanent approach for post-disaster school reconstruction. The highlighted criteria and the proposed design strategies contribute to the “build back better” attempt by providing better learning experiences for children through a replicable modular design that could be flexibly adapted to various local contexts.
Public leadership and the wicked problem continuum
Authors: Wexler Mark N. , Oberlander Judy
Published: September 2020

Purpose

This paper examines the relevance of the wicked problem continuum, particularly the emergence of super wicked challenges for public leadership researchers. Contemporary theorizing on public leadership adequately deals with tame challenges, struggles with wicked problems and remains in the dark with regards to the implications of super wicked problems

Design/methodology/approach

The wicked problem continuum provides a typology or set of dilemmas running from tame to wicked through to super wicked problems. These different problem types are treated as if they were on a three-zone continuum in which the difficulty of solving or substantially reducing the problem varies from relatively low to very high.

Findings

We delineate the three-problem contexts in the wicked problem continuum and discuss the ideal type of organization thriving in each zone. We then posit two opposing wicked problem interpretations-taming and wilding- for those interested in public leadership. Taming calls for prudent, results-oriented leaders employing tried and tested practices. Wilding demands leaders who test the status quo by seeking alternatives.

Social implications

On the global leadership agenda, wilding problems—those calling attention to the super wicked zone—are escalating. Despite this, public leaders' training lacks a framework for making sense of these urgent and publicly contentious super wicked problems.

Originality/value

Public policy researchers are beginning to direct attention to super wicked problems such as climate change, and pandemics. This work introduces the wicked problem continuum and demonstrates its pertinence for researchers of public leadership.
Leading in the shadows: understanding administrative leadership in the context of COVID-19 pandemic management in Bangladesh
Authors: Alam M Aslam
Published: September 2020

Purpose

This article aims to examine the COVID-19 pandemic management system in Bangladesh and the role played by various bureaucratic leaders both at national and local levels. Particularly, attention is paid to the interface between the health sector and administrative leaders. The role played by front-line public servants and their superiors are also examined. Also, an attempt is made to encapsulate lessons learned from the crisis and the ways to prepare for the next one.

Design/methodology/approach

This study is based on secondary data and observation by the author as well as insights from the author's 36 years of experience in the Bangladesh bureaucracy. Administrative leadership is conceptualized as bureaucrats appointed to administrative positions and discharging administrative duties both at the national and local levels.

Findings

A disfunctionality in the COVID-19 management system is observed, which is a direct consequence of the administrative leaders' preference for leading from behind. Some structural constraints in the system are also uncovered.

Originality/value

It draws on observations, experiences and insights from the author's long association with the Bangladesh administrative system. Its intended users are researchers and practitioners of public leadership.
Cash holdings: Do they boost or hurt firms’ performance? Evidence from listed non-financial firms in Saudi Arabia
Authors: Alnori Faisal
Published: September 2020

Purpose

The purpose of this paper is to study the relationship between corporate cash holdings and financial performance, both linearly and non-linearly, for listed non-financial firms in Saudi Arabia.

Design/methodology/approach

The data include all listed firms in Saudi Arabia’s primary stock market, excluding banks and insurance companies, over 2005–2016. The source for all data is the Osiris database. In evaluating the association between cash holdings and financial performance, static (i.e. pooled ordinary least squares) and dynamic (i.e. system generalized method of moments) specifications were implemented. Further, to confirm the non-linear linkage between cash reserves and financial performance, a U test was used.

Findings

The findings show that cash holdings play a significant role in firms’ performance; specifically, this relationship is non-linear, exhibiting an inverse U shape, driven by levels of cash reserves. This non-linear relationship verifies the tenets of the trade-off theory of optimum cash level based on the benefits and costs of holding cash.

Research limitations/implications

It is recommended that future studies investigate corporate liquidity and performance among Shariah-compliant firms and their conventional counterparts.

Practical implications

The findings of this study provide useful insights for managers and policymakers on efficient levels of corporate liquidity management.

Social implications

This paper provides further insights for investors on the role of corporate cash holding levels in firm performance.

Originality/value

To the best of the author’s knowledge, this paper is among the first to explore a non-linear relationship between cash holdings and firms’ performance using accounting measures.
Energy performance certificates and house prices: a quantile regression approach
Authors: McCord Michael , Haran Martin , Davis Peadar , McCord John
Published: September 2020

Purpose

A number of studies have investigated the relationship between energy performance certificates (EPCs) and house prices. A majority of studies have tended to model energy performance pricing effects within a traditional hedonic conditional mean estimate model. There has been limited analysis that has accounted for the relationship between EPCs and the effects across the pricing distribution. Moreover, there has been limited research examining the “standard cost improvements EPC score”, or “potential score”. Therefore, this paper aims to quantify and measure the dynamic effects of EPCs on house prices across the price spectrum and account for standardised cost-effective retrofit improvements.

Design/methodology/approach

Existing EPC studies produce one coefficient for the entirety of the pricing distribution, culminating in a single marginal implicit price effect. The approach within this study applies a quantile regression approach to empirically estimate how quantiles of house prices respond differently to unitary changes in the proximal effects of EPCs and structural property characteristics across the conditional distribution of house prices. Using a data set of 1,476 achieved transaction prices, the quantile regression models apply both assessed EPC score and bands and further examine the potential EPC rating for improved energy performance based on an average energy cost improvement.

Findings

The findings show that EPCs are valued differently across the quantiles and that conditional quantiles are asymmetrical. Only property prices in the upper quantiles of the price distribution show significant capitalisation effects with energy performance, and only properties with higher EPC scores display positive significant effects at the higher end of the price distribution. There are also brown discount effects evident for lower-rated properties within F- and G-rated EPC properties at the higher end of the pricing distribution. Moreover, the potential energy efficiency rating (score) also shows increased effects with sales prices and appears to minimise any brown discount effects. The findings imply that energy performance is a complex feature that is not easily “averaged” for valuation effect purposes.

Originality/value

While numerous studies have investigated the pricing effects of EPCs, they have tended to provide a single estimate to determine the relationship with price. This paper extends the traditional analytical insights beyond the conditional mean estimate by examining the quantiles of the relationship between EPCs and house prices to enhance the understanding of this esoteric and complex issue. In addition, this research applies the assessed energy efficiency potential to establish whether effective cost improvements enhance the relationship with sales price and capitalisation effects.