bluuebunny/crossref_metadata_2025 huggingface dataset:
Elf1 promotes Rad26’s interaction with lesion-arrested Pol II for transcription-coupled repair
Authors: Sarsam Reta D , Xu Jun , Lahiri Indrajit , Gong Wenzhi , Oh Juntaek , Zhou Zhen , Chong Jenny , Hao Nan , Li Shisheng , Wang Dong , Leschziner Andres E.
Published: September 2023

Transcription-coupled nucleotide excision repair (TC-NER) is a highly conserved DNA repair pathway that removes bulky lesions in the transcribed genome. Cockayne syndrome B protein (CSB), or its yeast ortholog Rad26, has been known for decades to play important roles in the lesion-recognition steps of TC-NER. Another conserved protein ELOF1, or its yeast ortholog Elf1, was recently identified as a core transcription-coupled repair factor. How Rad26 distinguishes between RNA polymerase II (Pol II) stalled at a DNA lesion or other obstacles and what role Elf1 plays in this process remains unknown. Here, we present cryo-EM structures of Pol II-Rad26 complexes stalled at different obstacles that show that Rad26 uses a universal mechanism to recognize a stalled Pol II but interacts more strongly with a lesion-arrested Pol II. A cryo-EM structure of lesion-arrested Pol II-Rad26 bound to Elf1 revealed that Elf1 induces new interactions between Rad26 and Pol II when the complex is stalled at a lesion. Biochemical and genetic data support the importance of the interplay between Elf1 and Rad26 in TC-NER initiation.
Overexpression of Rheb, a positive Tor regulator, reveals principles of rod outer segment size control
Authors: Gilliam Larissa , Willoughby John J , Annan William , White Diana , Jensen Abbie M
Published: September 2023

The outer segment of retinal rod photoreceptors is a highly modified cilium with the typical ciliary microtubular axoneme but additionally there are hundreds of densely packed, stacked, discrete intramembranous discs containing phototransduction machinery. The outer segment is continuously regenerated or renewed throughout the life of the animal through the combined processes of proximal growth and distal shedding. Since the pioneering experiments decades ago that demonstrated the process of rod outer segment renewal very little research has been directed towards understanding mechanistic principles of renewal and homeostasis, and many important questions remain unaddressed. The rod outer segment is a prime example of tight size control that is amenable to experimental and computational analyses. This study uses zebrafish molecular genetics with high resolution imaging, quantitative analyses, and computational modeling to uncover principles that regulate rod outer segment homeostatic length control. By genetically increasing rod outer segment growth, we show that outer segments lengthen and shedding does not accelerate to offset this added growth.
Intrinsic and extrinsic factors regulate FtsZ function inCaulobacter crescentus
Authors: Barrows Jordan M , Anderson Ashley S , Talavera-Figueroa Barbara K , Goley Erin D
Published: September 2023

Bacterial cell division is crucial for replication and requires careful coordination via a complex set of proteins collectively known as the divisome. The tubulin-like GTPase FtsZ is the master regulator of this process and serves to recruit downstream divisome proteins and regulate their activities. Upon arrival at mid-cell, FtsZ associates with the membrane via anchoring proteins and exhibits treadmilling motion, driven by its GTP binding and hydrolysis activities. Treadmilling is proposed to play a role in Z-ring condensation, as well as in distribution and regulation of peptidoglycan (PG) cell wall remodeling enzymes. FtsZ polymer superstructure and dynamics are central to its function, yet their regulation is incompletely understood. We sought to address these gaps in knowledge by modulating intrinsic and extrinsic regulators of FtsZ and evaluating their effectsin vitroand in cells, alone and in combination. To do this, we leveraged the cell cycle control features ofCaulobacter crescentus.We observed thatCaulobacterFtsZ variants that abrogate GTP hydrolysis impact FtsZ dynamics and Z-ring positioning, with little to no effect on Z-ring structure or constriction. Production of an FtsZ variant lacking its disordered C-terminal linker (ΔCTL) resulted in aberrant Z-ring dynamics and morphology, misregulated PG metabolism, and cell lysis. Combining ΔCTL and GTPase mutations was additive, suggesting they each act independently to control the Z-ring. Modulating levels of FtsA resulted in formation of multiple Z-rings that failed to constrict, suggesting roles in regulating both FtsZ superstructure and the activity of downstream divisome components. Collectively, our results indicate that GTP hydrolysis serves primarily to position the Z-ring at mid-cell, the CTL regulates both Z-ring structure and downstream signaling, and FtsA contributes to all aspects of FtsZ assembly and function. The additive effects of these elements are required to support robust and efficient cell division.
Potential of Ilhéus virus to emerge
Authors: Plante Kenneth S. , Plante Jessica A. , Azar Sasha R. , Shinde Divya P. , Scharton Dionna , Versiani Alice F. , Oliveira da Silva Natalia Ingrid , Strange Taylor , Sacchetto Lívia , Fokam Eric B. , Rossi Shannan L. , Weaver Scott C. , Marques Rafael E. , Nogueira Mauricio L. , Vasilakis Nikolaos
Published: September 2023

Ilhéus virus (ILHV)(Flaviviridae: Orthoflavivirus) is an arthropod-borne virus (arbovirus) endemic to Central and South America and the Caribbean. First isolated in 1944, most of our knowledge derives from surveillance and seroprevalence studies. These efforts have detected ILHV in a broad range of mosquito and vertebrate species, including humans, but laboratory investigations of pathogenesis and vector competence have been lacking. Here, we develop several immune intact murine models that closely recapitulate human neuroinvasive disease with strain- and age-specific virulence, as well as a uniformly lethal immunocompromised model. Replication kinetics in several vertebrate and invertebrate cell lines demonstrate that ILHV is capable of replicating to high titers in a wide variety of potential host and vector species. Lastly, vector competence studies provide strong evidence for efficient infection of and potential transmission byAedesspecies mosquitoes, despite ILHV’s phylogenetically clustering withCulexvectored flaviviruses, suggesting ILHV is poised for emergence in the neotropics.

Teaser

Murine models of ILHV mimic human disease, andAedesspecies of mosquitoes are highly susceptible to infection and dissemination.
Influence of FTDP-17 mutants on circular Tau RNAs
Authors: Margvelani Giorgi , Welden Justin R. , Maquera Andrea Arizaca , Van Eyk Jennifer E. , Murray Christopher , Miranda Sardon Sandra C. , Stamm Stefan
Published: September 2023

At least 53 mutations in the microtubule associated protein tau gene (MAPT) have been identified that cause frontotemporal dementia. 47 of these mutations are localized between exons 7 and 13. They could thus affect the formation of circular RNAs (circRNAs) from the MAPT gene that occur through backsplicing from exon 12 to either exon 10 or exon 7. We analyzed representative mutants and found that five FTDP-17 mutations increase the formation of 12➔7 circRNA and three different mutations increase the amount of 12➔10 circRNA. CircRNAs are translated after undergoing adenosine to inosine RNA editing, catalyzed by ADAR enzymes. We found that the interferon induced ADAR1-p150 isoform has the strongest effect on circTau RNA translation. ADAR1-p150 activity had a stronger effect on circTau RNA expression and strongly decreased 12➔7 circRNA, but unexpectedly increased 12➔10 circRNA. In both cases, ADAR-activity strongly promoted translation of circTau RNAs. Unexpectedly, we found that the 12➔7 circTau protein interacts with eukaryotic initiation factor 4B (eIF4B), which is reduced by four FTDP-17 mutations located in the second microtubule domain. These are the first studies of the effect of human mutations on circular RNA formation and translation. They show that point mutations influence circRNA expression levels, likely through changes in the secondary pre-mRNA structures. The effect of the mutations is surpassed by editing of the circular RNAs, leading to their translation. Thus, circular RNAs and their editing status should be considered when analyzing FTDP-17 mutations.

Highlights

47/53 known FTDP-17 mutations are located in regions that could influence generation of circular RNAs from the MAPT gene

Circular Tau RNAs are translated after adenosine to inosine RNA editing, most effectively caused by ADAR1-p150

FTDP-17 mutations influence both circTau RNA and circTau protein expression levels

CircTau protein expression levels do not correlate with circTau RNA expression levels

CircTau proteins bind to eukaryotic initiation factor 4B, which is antagonized by FTDP-17 mutations in exon 10

Graphic Abstract
Negative allosteric modulation of the µ-opioid receptor
Authors: O’Brien Evan S. , Rangari Vipin Ashok , Daibani Amal El , Eans Shainnel O. , White Betsy , Wang Haoqing , Shiimura Yuki , Kumar Kaavya Krishna , Appourchaux Kevin , Huang Weijiao , Zhang Chensong , Mathiesen Jesper M. , Che Tao , McLaughlin Jay P. , Majumdar Susruta , Kobilka Brian K.
Published: September 2023

The µ-opioid receptor (µOR) is a well-established target for analgesia, yet conventional opioid receptor agonists cause serious adverse effects, notably addiction and respiratory depression, which have led to the present opioid overdose epidemic. µOR negative allosteric modulators (NAMs) may serve as powerful tools in preventing opioid overdose deaths, but promising chemical scaffolds remain elusive. We screened a large DNA-encoded chemical library against inactive µOR, counter-screening with active, G-protein and agonist bound receptor to “steer” selections toward functional negative allosteric modulators. We discovered a NAM compound with high and selective enrichment to inactive µOR; the molecule potently blocks the activity of orthosteric agonists and enhances the affinity of the key opioid overdose reversal molecule, naloxone. It accomplishes this by binding to a site on the extracellular vestibule proximal to naloxone, stabilizing a unique inactive conformation of the extracellular portions of the second and seventh transmembrane helices. The NAM perturbs orthosteric ligand kinetics in therapeutically desirable ways and works cooperatively with low doses of naloxonein vivoto inhibit morphine-induced antinociception, respiratory depression and conditioned place preference while minimizing withdrawal behaviors. Our results provide detailed structural insights into the mechanism of a negative allosteric modulator for the µOR and demonstrate how it can be exploitedin vivo.
Mass spectrometry and split luciferase complementation assays reveal the MecA protein interactome ofStreptococcus mutans
Authors: Qin Hua , Anderson David , Zou Zhengzhong , Higashi Dustin , Borland Christina , Kreth Jens , Merritt Justin
Published: September 2023

MecA is a highly conserved adaptor protein encoded by prokaryotes from theBacillotaphylum. MecA mutants exhibit similar pleiotropic defects in a variety of organisms, although most of these phenotypes currently lack a mechanistic basis. MecA mediates ClpCP-dependent proteolysis of its substrates, but only several such substrates have been reported in the literature and there are suggestions that proteolysis-independent regulatory mechanisms may also exist. Here, we provide the first comprehensive characterization of the MecA interactome and further assess its regulatory role in Clp-dependent proteolysis. Untargeted coimmunoprecipitation assays coupled with mass spectrometry revealed that the MecA ortholog from the oral pathobiontStreptococcus mutanslikely serves as a major protein interaction network hub by potentially complexing with >100 distinct protein substrates, most of which function in highly conserved metabolic pathways. The interactome results were independently verified using a newly developed prokaryotic split luciferase complementation assay (SLCA) to detect MecA protein-protein interactionsin vivo. In addition, we further develop a new application of SLCA to supportin vivomeasurements of MecA relative protein binding affinities. SLCA results were independently verified using targeted coimmunoprecipitation assays, suggesting the general utility of this approach for prokaryotic protein-protein interaction studies. Our results indicate that MecA indeed regulates its interactome through both Clp-dependent proteolysis as well as through an as yet undefined proteolysis-independent mechanism that may affect more than half of its protein interactome. This suggests a significant aspect of MecA regulatory function still has yet to be discovered.
No evidence for a causal contribution of bioavailable testosterone to ADHD in sex-combined and sex-specific two-sample Mendelian randomization studies
Authors: Dinkelbach Lars , Peters Triinu , Grasemann Corinna , Hebebrand Johannes , Hinney Anke , Hirtz Raphael
Published: September 2023

The higher prevalence of attention-deficit/hyperactivity disorder (ADHD) in males raises the question of whether testosterone is implicated in ADHD risk. However, cross-sectional studies did not identify an association between ADHD and testosterone levels. Mendelian randomization (MR) studies can overcome limitations inherent to association studies, especially of reverse causation and residual confounding. In the current study, sex-combined and sex-specific two-sample MR analyses were conducted to address whether testosterone has a causal influence on ADHD risk. Sex-combined as well as sex-specific target-genetic variants for bioavailable testosterone were derived from a large genome-wide association study (GWAS) on up to 382,988 adult white European UK Biobank study participants. In our sex-specific analyses for ADHD, including data from 14,154 males and 4,945 females (17,948 and 16,246 controls respectively), no association between bioavailable testosterone and ADHD risk were found, neither in males (inverse-variance weighted (IVW): beta=0.09, 95%-CI [-0.10, 0.27]) nor in females (IVW: beta=-0.01, 95%-CI [-0.20, 0.19]). However, in the sex-combined analysis, including 38,691 cases and 186,843 controls, genetically predicted bioavailable testosterone was associated with ADHD risk (IVW: beta=0.24, 95%-CI [0.09, 0.39). The inclusion of birth weight and/or SHBG as additional variables in multivariable MR analyses did not alter this result. However, when correcting for potential BMI-driven pleiotropy by a multivariable MR study, all effect estimates for testosterone showed non-significant results. Taken together, no robust evidence for a causal effect of bioavailable testosterone on the risk for ADHD was found.
Dietary sulfur amino acid restriction in humans with overweight and obesity: a translational randomized controlled trial
Authors: Olsen Thomas , Stolt Emma , Øvrebø Bente , Elshorbagy Amany , Tore Elena C. , Lee-Ødegård Sindre , Troensegaard Hannibal , Johannessen Hanna , Doeland Beate , Vo Anna A. D. , Dahl Anja F. , Svendsen Karianne , Thoresen Magne , Refsum Helga , Rising Russell , Barvíková Kristýna , van Greevenbroek Marleen , Kožich Viktor , Retterstøl Kjetil , Vinknes Kathrine J.
Published: September 2023

Dietary sulfur amino acid restriction (SAAR) improves metabolic health in animals, but in humans, SAAR has not been investigated in translational clinical trials. In this study, we investigated the effect of dietary SAAR on body weight, body composition, resting metabolic rate, gene expression profiles in white adipose tissue (WAT), and an extensive blood biomarker profile in 59 humans with overweight and obesity in a double-blind, randomized controlled trial (ClinicalTrials.gov:NCT04701346). Participants were randomized to a plant-based diet low (∼2 g/d, SAAR) or high (∼5.6 g/d, control group) in sulfur amino acids. The diets were provided in full to the participants. After 8 weeks of intervention, SAAR led to a ∼20 % greater weight loss compared to controls (β (95 % CI) -1.14 (-2.04, -0.25) kg, p = 0.012). Despite greater weight loss, resting metabolic rate remained similar between groups. Furthermore, SAAR decreased serum leptin, and increased ketone bodies compared to controls. In WAT, 20 genes were upregulated whereas 24 genes were downregulated (FDR < 5 %) in the SAAR group compared to controls. Generally applicable gene set enrichment analyses revealed that processes associated with ribosomes were upregulated, whereas processer related to structural components were downregulated. In conclusion, our study shows that SAAR leads to weight loss and metabolic benefits. Further research SAAR is needed to investigate the therapeutic potential for metabolic conditions in humans.
Dendrite: A Structured, Accessible, and Queryable Pathology Search Database for Streamlined Experiment Planning
Authors: Lu Yunrui , Hamilton Robert , Greenberg Jack , Srinivasan Gokul , Shah Parth , Preum Sarah , Pettus Jason , Vaickus Louis , Levy Joshua
Published: September 2023

Pathology reports contain vital information, yet a significant portion of this data remains underutilized in electronic medical record systems due to the unstructured and varied nature of reporting. Although synoptic reporting has introduced reporting standards, the majority of pathology text remains free-form, necessitating additional processing to enable accessibility for research and clinical applications. This paper presents Dendrite, a web application designed to enhance pathology research by providing intelligent search capabilities and streamlining the creation of study cohorts. Leveraging expert knowledge and natural language processing algorithms, Dendrite converts free-form pathology reports into structured formats, facilitating easier querying and analysis. Using a custom Python script, Dendrite organizes pathology report data, enabling record linkages, text searches, and structured drop-down menus for information filtering and integration. A companion web application enables data exploration and export, showcasing its potential for further analysis and research. Dendrite, derived from existing laboratory information systems, outperforms existing implementations in terms of speed, responsiveness, and flexibility. With its efficient search functionality and support for clinical research and quality improvement efforts in the pathology field, Dendrite proves to be a valuable tool for pathologists. Future enhancements encompass user management integration, integration of natural language processing and machine learning to enhance structured reporting capabilities and seamless integration of Dendrite with the vast repository of genomics and imaging data.
WITHDRAWN: Prenatal exposure to wildfire-related PM2.5and respiratory infections by age 1 year: A population-based case-control analysis of critical developmental windows
Authors: Lan Qingyi , Weinberger Kate , Luke Sabrina , Lavigne Eric , Weichenthal Scott , Henderson Sarah B.
Published: September 2023

Withdrawal Statement

The authors have withdrawn this manuscript because they identified major flaws in their methods, and after re-analysis, their previous conclusion could not be supported. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.
Orientation tests and long-term movement phenology establish the red admiralVanessa atalantaas an applicable model for navigation research in migratory butterflies
Authors: Pakhomov Alexander , Jansons Roberts , Shapoval Nazar , Cellarius Fyodor , Shapoval Anatoly , Lindecke Oliver
Published: September 2023

Animal migrations are disappearing globally, while insect populations are on alarming declines. Both ecosystem degradations, influenced by unpredictable impacts of climate change, are also exacerbated by human activities such as intensified land use and various forms of environmental pollution. Butterfly migrations may serve as sensitive indicator phenomena of these broader environmental changes. While the transcontinental journeys of one of the most famous Lepidopteran species, the North American monarch butterfly,Danaus plexippus, are documented in depth, they are a geographically restricted phenomenon. Comprehensive studies from other areas and on other migratory butterflies like the European red admiral,Vanessa atalanta, are notably sparse. In addition, the details of their navigational capacities and how they might be affected by the aforementioned changes remain largely enigmatic. Against this backdrop, we seek to establish the red admiral as a model for insect movement phenology and navigation behaviour which both might be impacted by environmental changes. Employing a combination of orientation tests, utilizing flight-simulators and free-flight trials during late summer, together with a 23-year study on movement phenology at a coastal migration flyway, the Baltic Sea coast, we offer broad insights into red admiral migration. In our experiments, butterflies exhibited a southwestern orientation on the Courish Spit and chose a south-southeastern trajectory in free-flight trials after translocation at the Latvian Baltic Sea coast. Directional records from decades-long trapping data, based on more than 16,000 individuals, match these findings. Nevertheless, we also found reverse movements to occur under some circumstances. At the same time, the observed estimated median dates of red admiral passages did change by one day only between decades, however, generally more butterflies were recorded in recent years. Our data thus suggest a certain degree of adaptability in the butterflies’ movement behaviour, indicating an innate migration schedule, possibly supported by a flexible navigational capacity. As the world is facing biodiversity loss at a high rate, long-term monitorings of indicator species become important. By establishing the red admirals as a model for butterfly migration, we expect insights into broader movement patterns and navigational strategies in Lepidoptera negotiating human-dominated environments, filling a crucial gap in our current understanding of these interdependent aspects of insect biology.
Progesterone induces meiosis through two obligate co-receptors with PLA2 activity
Authors: Nader Nancy , Assaf Lama , Zarif Lubna , Halama Anna , Yadav Sharan , Dib Maya , Attarwala Nabeel , Chen Qiuying , Suhre Karsten , Gross Steven S. , Machaca Khaled
Published: September 2023

The steroid hormone progesterone (P4) regulates multiple aspects of reproductive and metabolic physiology. Classical P4 signaling operates through nuclear receptors that regulate transcription. In addition, P4 signals through membrane P4 receptors (mPRs) in a rapid nongenomic modality. Despite the established physiological importance of P4 nongenomic signaling, the details of its signal transduction cascade remain elusive. Here, usingXenopusoocyte maturation as a well- established physiological readout of nongenomic P4 signaling, we identify the lipid hydrolase ABHD2 (α/β hydrolase domain-containing protein 2) as an essential mPRβ co-receptor to trigger meiosis. We show using functional assays coupled to unbiased and targeted cell-based lipidomics that ABHD2 possesses a phospholipase A2 (PLA2) activity that requires mPRβ. This PLA2 activity bifurcates P4 signaling by inducing clathrin-dependent endocytosis of mPRβ, resulting in the production of lipid messengers that are G-protein coupled receptors agonists. Therefore, P4 drives meiosis by inducing an ABHD2 PLA2 activity that requires both mPRβ and ABHD2 as obligate co-receptors.

Significance Statement

Nongenomic progesterone signaling is important for many physiological functions yet the details of its signaling remain elusive. Here we define the early signaling steps downstream of membrane progesterone receptor β (mPRβ) duringXenopusoocyte meiosis. We show that progesterone requires two cell membrane receptors to work in unison to signal. The co-receptor complex possesses lipase activity that produces lipid messenger and induces receptor endocytosis to trigger meiosis progression. Our findings have broad physiological implications because nongenomic progesterone signaling operates in many tissues and regulates reproduction and metabolism.
Accelerated physiology and increased energy expenditure in animals and humans with mitochondrial defects: A meta-analysis
Authors: Sercel Alexander J. , Sturm Gabriel , Shaulson Evan D. , Gallagher Dympna , St-Onge Marie-Pierre , Kempes Christopher P. , Pontzer Herman , Hirano Michio , Picard Martin
Published: September 2023

Mitochondria are key energy transforming organelles in mammalian cells. However, how defects in oxidative phosphorylation (OxPhos) and other mitochondrial functions influence whole-body energy expenditure (EE) has not been rigorously studied. Cellular and organismal responses to OxPhos defects likely involve a combination of functionaldownregulationto conserve energy and compensatoryupregulationof stress responses. If the energy cost of compensatory responses exceeds the potential energy savings of functional downregulation, as recent work suggests, the result would be an increase in total EE. To address the hypothesis that OxPhos defects increase the energetic cost of living, we performed a meta-analysis of available studies reporting EE in animal models with mitochondrial gene defects. Of all reported experimental conditions (n = 91, from 29 studies), 51% reported a >10% elevation in EE relative to control animals, compared to 11% reporting <10% reduction in EE (p<0.0001, Chi-square). Of the experimental conditions where locomotor activity was also quantified, 39% showed that OxPhos-deficient animals had elevated EE despite reduced locomotor activity, which would be expected to decrease EE. To extend this finding in humans, we re-analyzed a high-quality clinical and multi-omics dataset (Sharma et al. 2021) of mitochondrial disease patients with the m.3243A>G mutation. This analysis similarly indicates an upregulation of energetically costly physiological, immune, and metabolic parameters in people with OxPhos deficiency. These results suggest that animals and humans with mitochondrial defects must expend more energy to sustain life, a state clinically calledhypermetabolism. High-quality human energetics studies are needed to understand the magnitude, mechanisms, and modifiability of hypermetabolism in mitochondrial disorders.
Parallel G-quadruplex folds via multiple paths involving G-tract stacking and structuring from coil ensemble
Authors: Pokorná Pavlína , Mlýnský Vojtěch , Bussi Giovanni , Šponer Jiří , Stadlbauer Petr
Published: September 2023

G-quadruplexes (G4s) are non-canonical nucleic acid structures that fold through complex processes. Characterization of G4 folding landscape contributes to comprehending G4 roles in gene regulation but is challenging for experiments and computations. Here we investigate the folding of a three-quartet parallel DNA G4 with (GGGA)3GGG sequence using all-atom explicit-solvent enhanced-sampling molecular dynamics (MD) simulations. We suggest an early formation of guanine stacks in the G-tracts, which behave as semi-rigid blocks in the folding process. The parallel G4 folding is initiated by the formation of a collapsed compact coil-like ensemble. Structuring of the G4 from the coil then proceeds via various cross-like, hairpin, slip-stranded, and two-quartet ensembles and can bypass the G-triplex structure. While parallel G-hairpins are extremely unstable when isolated, they are more stable inside the coil structure. Folding of parallel G4 does not appear to involve any salient intermediates and, instead, it is an extremely multiple-pathway process. On the methodology side, we show that the AMBER DNA force field predicts the folded G4 to be less stable than the unfolded ensemble, uncovering substantial force-field issues. Overall, we provide unique atomistic insights into the folding landscape of parallel-stranded G4 but also reveal limitations of the state-of-the-art MD techniques.
Faa1 membrane binding drives positive feedback in autophagosome biogenesis via fatty acid activation
Authors: Baumann Verena , Achleitner Sonja , Tulli Susanna , Schuschnig Martina , Klune Lara , Martens Sascha
Published: September 2023

Autophagy serves as a stress response pathway by mediating the degradation of cellular material within lysosomes. In autophagy this material is encapsulated in double membrane vesicles termed autophagosomes, which form from precursors referred to as phagophores. Phagophores grow by lipid influx from the endoplasmic reticulum into Atg9-positive compartments and local lipid synthesis provides lipids for their expansion. How phagophore nucleation and expansion are coordinated with lipid synthesis is unclear. Here, we show that Faa1, an enzyme activating fatty acids, is directly recruited to Atg9 vesicles. We further show that Faa1 binds to negatively charged membranes. We define the membrane binding surface in Faa1 and show that membrane binding is required for its enzymatic activity. In cells, membrane binding by Faa1 is required for its recruitment to phagophores and promotes autophagosome biogenesis. Our results suggest a positive feedback loop coupling phagophore nucleation and expansion to lipid synthesis.

Baumann, Achleitner, Tulli et al. dissect Faa1 function and recruitment during autophagy. They discover that Faa1 directly binds membranes via a positively charged surface. This is a prerequisite for Faa1’s enzymatic activity sustaining autophagosome biogenesis.
Engineering the ADDobody protein scaffold for generation of high-avidity ADDomer super-binders
Authors: Buzas Dora , Sun Huan , Toelzer Christine , Yadav Sathish K. N. , Borucu Ufuk , Gautam Gunjan , Gupta Kapil , Bufton Josh , Capin Julien , Sessions Richard B. , Garzoni Frederic , Berger Imre , Schaffitzel Christiane
Published: September 2023

Adenovirus-derived dodecamer (ADDomer) nanoparticles comprise 60 copies of Adenovirus penton base protein (PBP). ADDomer is thermostable, rendering the storage, transport and deployment of ADDomer-based therapeutics independent of a cold-chain. To expand the scope of ADDomer nanoparticles for new applications, we engineered ADDobodies. ADDobodies represent the crown domain of the PBP, genetically separated from its multimerization domain. We inserted heterologous sequences into hyper-variable loops in the crown domain. The resulting ADDobodies were expressed at high yields inEscherichia coli,are monomeric and maintain thermostability. We solved the X-ray structure of an ADDobody prototype validating our design. We demonstrated that ADDobodies can be used to select a specific binder against a target inin vitroselection experiments using ribosome display, with an enrichment factor of ∼104-fold in one selection round. We show that ADDobodies can be converted back into ADDomers by genetically reconnecting the selected ADDobody with the PBP multimerization domain from a different species, giving rise to a multivalent nanoparticle, called Chimera, confirmed by a 2.2 Å structure determined by cryogenic electron microscopy (cryo-EM). Chimera comprises 60 binding sites, resulting in ultra-high, picomolar avidity to the target.
A role for APP in the development of astrocyte morphological complexity
Authors: Saint-Martin Margaux , Goda Yukiko
Published: September 2023

The amyloid precursor protein (APP), whose proteolytic cleavage gives rise to amyloid-βpeptide, has been extensively studied for its role in Alzheimer’s disease, but its physiological function remains less understood. In neurons, APP and its two homologs, the amyloid precursor-like protein 1 (APLP1) and 2 (APLP2), are present in the synaptic compartment and promote synaptogenesis. Over recent years, astrocytes, an abundant glial cell in the brain, have attracted much attention for their role in regulating synapse formation and function. Although APP is also found in astrocytes, its role in these cells remains largely unexplored. Here we have sought to investigate the expression and function of APP in rodent astrocytesin vitroandin vivo. We find that APP along with its family members, APLP1 and APLP2, are expressed in astrocytesin vitroandin vivo. In primary hippocampal cultures, shRNA-mediated knockdown of astrocytic APP, APLP1 or APLP2 compromises astrocyte morphological elaboration to varying degrees. We have then focused on APP to characterize its role in astrocyte development in the intact brain. We show that astrocytic APP shapes the morphological complexity of astrocyte processesin vivoand may also modulate postsynaptic assembly. Our results highlight a role of astrocytic APP and possibly of APLPs that could potentially impact neuronal functions.
NAD+depletion and altered mitochondrial function are key to the establishment of placental dysfunction in an inflammatory-driven subclass of preeclampsia
Authors: Jahan Fahmida , Vasam Goutham , Cariaco Yusmaris , Nik-Akhtar Abolfazl , Green Alex , Menzies Keir J. , Bainbridge Shannon A.
Published: September 2023

Preeclampsia (PE) is a pregnancy associated hypertensive disease. It is one of the major causes of pregnancy-related maternal/perinatal adverse health outcomes, with a lack of highly effective preventative strategies and/or therapeutic interventions. Our group has previously identified distinct subclasses of pathophysiology underlying a PE diagnosis, one of which exhibits heightened immune activation at the gestational parent-fetal interface, identified as inflammatory-driven PE. In non-pregnant populations, chronic inflammation is associated with reduced cellular availability of NAD+, a vitamin B3-derived metabolite involved in energy metabolism and mitochondrial function. Interestingly, specifically in placentas from women with inflammatory-driven PE, we observed increased activity of NAD+-consuming PARP enzymes and reduced NAD+content. Moreover, these placentas had decreased expression of several mitochondrial oxidative phosphorylation (OXPHOS) proteins and evidence of oxidative damage. This human data was supported by cell culture findings, which likewise demonstrated increased PARP activity, coupled to decreased mitochondrial respiration rates and decreased invasive function of cultured HTR8 human trophoblast cells, following inflammatory induction by TNF-α. Importantly, these adverse inflammatory effects were attenuated by boosting cellular NAD+levels with nicotinamide riboside (NR). Finally, using an LPS-induced rodent model of inflammatory-driven PE, we demonstrated that NR administration (200mg/kg/day) from gestational day (GD) 1-19 could prevent the development of maternal hypertension and fetal/placental growth restriction, improve placental mitochondrial function, reduce placental inflammation and oxidative stress. Thus, this study demonstrates the critical role of NAD+metabolism in maintaining healthy placental function and identifies NAD+boosting as a promising preventative strategy for the inflammatory-driven subclass of PE.

One sentence summary

Boosting NAD+levels prevent inflammatory-driven preeclampsia by improving placental mitochondrial function.
A frequency peak at 3.1 kHz obtained from the spectral analysis of the cochlear implant electrocochleography noise
Authors: Herrada Javiera , Medel Vicente , Dragicevic Constantino , Maass Juan C. , Stott Carlos E. , Delano Paul H.
Published: September 2023

Introduction

The functional evaluation of auditory-nerve activity in spontaneous conditions has remained elusive in humans. In animals, the frequency analysis of the round-window electrical noise recorded by means of electrocochleography yields a frequency peak at around 900 to 1000 Hz, which has been proposed to reflect auditory-nerve spontaneous activity. Here, we studied the spectral components of the electrical noise obtained from cochlear implant electrocochleography in humans.

Methods

We recruited adult cochlear implant recipients from the Clinical Hospital of the Universidad de Chile, between the years 2021 and 2022. We used the AIM System from Advanced Bionics® to obtain single trial electrocochleography signals from the most apical electrode in cochlear implant users. We performed a protocol to study spontaneous activity and auditory responses to 0.5 and 2 kHz tones

Results

Twenty subjects including 12 females, with a mean age of 57.9 ± 12.6 years (range between 36 and 78 years) were recruited. The electrical noise of the single trial cochlear implant electrocochleography signal yielded a reliable peak at 3.1 kHz in 55% of the cases (11 out of 20 subjects), while an oscillatory pattern that masked the spectrum was observed in seven cases. In the other two cases, the single-trial noise was not classifiable. Auditory stimulation at 0.5 kHz and 2.0 kHz did not change the amplitude of the 3.1 kHz frequency peak.

Conclusion

We found two main types of noise patterns in the frequency analysis of the single-trial noise from cochlear implant electrocochleography, including a peak at 3.1 kHz that might reflect auditory-nerve spontaneous activity, while the oscillatory pattern probably corresponds to an artifact.
Oligomeric states of an Influenza-encoded PB1-F2 viroporin
Authors: Jamal Sehrish , Moin Syed Tarique , Haider Shozeb
Published: September 2023

Influenza Viruses have always been a major health concern due to their highly contagious nature. The PB1-F2 viroporin encoded by the influenza A virus is known to be a pro-apoptotic protein involved in cell death induction of the host immune cells. The structural arrangement and the mode of action of PB1-F2 viroporin have not been fully understood. In this study, we report on the most probable oligomeric structural existences of PB1-F2, investigated by Molecular Dynamics Simulations with improved sampling of conformational states. The simulations provide a channel framework to study the mitochondrial membrane permeation pathway which could initiate the leakage of mitochondrial contents like cytochrome C and induce apoptosis. The structural attributes of the oligomeric states were rigorously evaluated by comparing the experimental reports. Our results reveal a tetrameric form as the preferable state in the lipid environment. This further fulfills the ion transportation criteria by providing a less energetic barrier to ions/water molecules crossing the membrane.
What is the prevalence of orthostatic hypotension in an Australasian emergency department population?
Authors: Clemensen Ellie , Lau Gabriel T , Popovic Gordana
Published: September 2023

Objective

Orthostatic hypotension (OH) is associated with increased morbidity and there is limited research on the prevalence in the Australian ED population. The aim was to determine the prevalence of OH in an Australian ED population. Secondary outcomes included any associations of OH with symptoms, presenting complaints, patient demographics, or hospital admission, and the timing of OH findings.

Methods

Patients presenting to a regional Australasian ED underwent orthostatic measurements at 1, 3 and 5 min of standing following 5 min of supine bed rest. OH was defined as a drop in systolic and/or diastolic blood pressure by ≥20 and ≥10 mmHg, respectively.

Results

Of the 312 patients who were enrolled in the study, 69 (22.1%, 95% confidence interval 17.7–27.2%) had OH and 76.8% of cases were detected after 3 min of standing. There was evidence of difference in the prevalence of OH with age (P < 0.001). Similarly, there was evidence of a difference in supine systolic and diastolic blood pressure measurements (P = 0.012 and P < 0.001, respectively) between orthostatic and normotensive subjects. No association was found with OH and hospital admission, presenting complaints or comorbid medical illnesses.

Conclusions

In this single Australian ED population, there was a high prevalence of OH (22.1%) with most cases detected within 3 min of standing. A higher‐powered study across multiple sites would better substantiate these findings.
Genomics, transcriptomics, and peptidomics of the greater wax moth Galleria mellonella neuropeptides and their expression in response to lead stress
Authors: Luo Li‐Lin , Lin Yang , Linghu Jun‐Hong , Gong Wei , Luo Yuan‐Hong , Liu Man , Jin Dao‐Chao , Smagghe Guy , Liu Tong‐Xian , Gui Shun‐Hua , Yi Tian‐Ci
Published: September 2023

Neuropeptides are crucial in regulation of a rich variety of developmental, physiological, and behavioral functions throughout the life cycle of insects. Using an integrated approach of multiomics, we identified neuropeptide precursors in the greater wax moth Galleria mellonella, which is a harmful pest of honeybee hives with a worldwide distribution. Here, a total of 63 and 67 neuropeptide precursors were predicted and annotated in the G. mellonella genome and transcriptome, in which 40 neuropeptide precursors were confirmed in the G. mellonella peptidome. Interestingly, we identified 12 neuropeptide precursor genes present in G. mellonella but absent in honeybees, which may be potential novel pesticide target sites. Honeybee hives were contaminated with heavy metals such as lead, enabling its bioaccumulation in G. mellonella bodies through the food chain, we performed transcriptome sequencing to analyze the effects of Pb stress on the mRNA expression level of G. mellonella neuropeptide precursors. After treatment by Pb, the expression of neuropeptide F1 was found to be significantly downregulated, implying that this neuropeptide might be associated with responding to the heavy metal stress in G. mellonella. This study comprehensively identified neuropeptide precursors in G. mellonella, and discussed the effects of heavy metals on insect neuropeptides, with the example of G. mellonella. The results are valuable for future elucidation of how neuropeptides regulate physiological functions in G. mellonella and contribute to our understanding of the insect's environmental plasticity and identify potential new biomarkers to assess heavy metal toxicity in insects.
Alcohol and cannabis dual use among Black adults: Associations with alcohol use, use‐related problems, and race‐based discrimination
Authors: Buckner Julia D. , Zvolensky Michael J. , Scherzer Caroline R.
Published: September 2023

Background and Objectives

Black adults who drink alcohol appear at risk for poor alcohol‐related outcomes, yet little research has examined whether cannabis use among those who consume alcohol (alcohol‐cannabis dual use) is related to worse alcohol‐related consequences, as observed in predominantly White samples. Further, it may be that experiencing more race‐based discrimination may be related to using multiple substances to cope with such experiences; however, no known studies have examined the impact of race‐based discrimination on alcohol‐cannabis dual use.

Methods

Participants were 270 Black undergraduates who endorsed past‐month drinking, 112 of whom endorsed alcohol‐cannabis dual use.

Results

The dual use group reported heavier drinking, more drinking‐related problems, and more race‐based microaggressions (but not overt racism) than the alcohol‐only group.

Conclusions

The use of cannabis among Black young adults who drink alcohol was related to heavier drinking and more alcohol‐related problems. Further, experiencing more microaggressions may place these individuals at risk for using multiple substances, presumably to cope with these experiences.

Scientific Significance

Considering models suggesting that the dual use of cannabis may result in less alcohol use, the current study highlights that for Black adults who consume alcohol, cannabis dual use is related to heavier drinking and more alcohol‐related problems, which can inform intervention and treatment efforts.
Opioid and benzodiazepine misuse in the United States: The impact of socio‐demographic characteristics
Authors: Haider Mohammad Rifat , Jayawardhana Jayani
Published: September 2023

Background and Objectives

In 2021, drug overdose deaths in the United States reached a new record of 107,622. Misuse of opioids and benzodiazepines accounts for a large portion of drug overdose deaths. However, the effects of socio‐demographic characteristics on misuse of opioids and benzodiazepines are not evident. Thus, this study examines the socio‐demographic characteristics associated with misuse of opioids and benzodiazepines among adults in the United States.

Methods

Data from 2015–2019 National Survey on Drug Use and Health was utilized in the multinomial logistic regression analysis and included 202,935 adults ages ≥18 years.

Results

During 2015–2019, 3.3% of the adults misused opioids, 1.2% misused benzodiazepines, and 0.9% misused both drugs in the preceding year of the survey. Those who were younger, bisexual, non‐Hispanic White, had a history of delinquency in the past year, had alcohol dependence/abuse, marijuana dependence/abuse, nicotine dependence and use, and experienced major depressive episodes were more likely to misuse opioids, benzodiazepines, or both.

Conclusion and Scientific Significance

A large portion of US adults are misusing opioids, benzodiazepines, and both drugs. Specifically, bisexual individuals experience higher odds of opioid misuse, benzodiazepine misuse and misuse of both drugs compared with heterosexuals, while males are experiencing lower odds of benzodiazepine misuse compared with females. Individuals aged 26–49 experience the highest odds of opioid misuse, though misuse of both drugs was higher among the 18–25 age group. Findings underscore the use of targeted preventive measures to reduce misuse of these drugs among at‐risk populations identified in this study.
Where Motivated Reasoning Withers and Looms Large: Fear and Partisan Reactions to the COVID‐19 Pandemic
Authors: Mehlhaff Isaac D. , Ryan Timothy J. , Hetherington Marc J. , MacKuen Michael B.
Published: September 2023

Contemporary American politics has been largely characterized by hyperpartisanship and polarization, with partisan‐motivated reasoning a thematic concern. Theories of emotions in politics suggest that anxiety might interrupt partisan heuristics and encourage citizens to reason more evenhandedly—but in what domains and to what extent? We use original panel data to assess how anxiety about becoming seriously ill from COVID‐19 interacted with partisan attachments to shape political judgment during the COVID‐19 pandemic. The structure of our data allows us to assess large‐scale implications of politically relevant emotions in ways that so far have not been possible. We find large effects on policy attitudes: Republicans who were afraid of getting sick rejected signals from copartisan leaders by supporting mask mandates and the like. Effects on vote choice for Republicans were muted in comparison, but fear's large effect on independents may have been pivotal.