bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amino acid substitutions hydrophilizing the core of titin domains cause dilated cardiomyopathy
Authors: Martinez-Martin Ines , Crousilles Audrey , Ochoa Juan Pablo , Velazquez-Carreras Diana , Mortensen Simon A. , Herrero-Galan Elias , Dominguez Fernando , Garcia-Pavia Pablo , de Sancho David , Wilmanns Matthias , Alegre-Cebollada Jorge 
Published: June 2023

ABSTRACTThe underlying genetic defect in most cases of dilated cardiomyopathy (DCM), a common inherited heart disease, remains unknown. Intriguingly, many patients carry single missense variants of uncertain pathogenicity targeting the giant protein titin, a fundamental sarcomere component. To explore the deleterious potential of these variants, we first solved the wild-type and mutant crystal structures of I21, the titin domain targeted by pathogenic variant p.C3575S. Although both structures are remarkably similar, the increase in hydrophilicity of deeply buried position 3575 strongly destabilizes the mutant domain, a scenario supported by molecular dynamics simulations and by biochemical assays that show no disulfide involving C3575. Prompted by these observations, we have found that thousands of similar hydrophilizing variants associate specifically with DCM. Hence, our results imply that titin domain destabilization causes DCM, a conceptual framework that not only informs pathogenicity assessment of gene variants but also points to therapeutic strategies counterbalancing protein destabilization.
Small regulatory RNAs are mediators of theStreptococcus mutansSloR regulon
Authors: Drummond India Y. , DePaolo Alessandra , Krieger Madeline , Driscoll Heather , Eckstrom Korin , Spatafora Grace A. 
Published: June 2023

ABSTRACTDental caries is among the most prevalent chronic infectious diseases worldwide.Streptococcus mutans, the chief causative agent of caries, uses a 25 kDa manganese dependent SloR protein to coordinate the uptake of essential manganese with the transcription of its virulence attributes. Small non-coding RNAs (sRNAs) can either enhance or repress gene expression and reports in the literature ascribe an emerging role for sRNAs in the environmental stress response. Herein, we identify 18-50 nt sRNAs as mediators of theS. mutansSloR and manganese regulons. Specifically, the results of sRNA-seq revealed 56 sRNAs inS. mutansthat were differentially transcribed in the SloR-proficient UA159 and SloR-deficient GMS584 strains, and 109 sRNAs that were differentially expressed in UA159 cells grown in the presence of low versus high manganese. We describe SmsR1532 and SmsR1785 as SloR- and/or manganese-responsive sRNAs that are processed from large transcripts, and that bind SloR directly in their promoter regions. The predicted targets of these sRNAs include regulators of metal ion transport, growth management via a toxin-antitoxin operon, and oxidative stress tolerance. These findings support a role for sRNAs in coordinating intracellular metal ion homeostasis with virulence gene control in an important oral cariogen.IMPORTANCESmall regulatory RNAs (sRNAs) are critical mediators of environmental signaling, particularly in bacterial cells under stress, but their role inStreptococcus mutansis poorly understood.S. mutans,the principal causative agent of dental caries, uses a 25 kDa manganese-dependent protein, called SloR, to coordinate the regulated uptake of essential metal ions with the transcription of its virulence genes. In the present study, we identified and characterize sRNAs that are both SloR- and manganese-responsive. Taken together, this research can elucidate the details of regulatory networks that engage sRNAs in an important oral pathogen, and that can enable the development of an effective anti-caries therapeutic.
The small protein MntS evolved from a signal peptide and acquired a novel function regulating manganese homeostasis inEscherichia coli
Authors: Wright Zachary , Seymour Mackenzie , Paszczak Kalista , Truttmann Taylor , Senn Katherine , Stilp Samuel , Jansen Nickolas , Gosz Magdalyn , Goeden Lindsay , Anantharaman Vivek , Aravind L. , Waters Lauren S. 
Published: June 2023

AbstractSmall proteins (< 50 amino acids) are emerging as ubiquitous and important regulators in organisms ranging from bacteria to humans, where they commonly bind to and regulate larger proteins during stress responses. However, fundamental aspects of small proteins, such as their molecular mechanism of action, downregulation after they are no longer needed, and their evolutionary provenance are poorly understood. Here we show that the MntS small protein involved in manganese (Mn) homeostasis binds and inhibits the MntP Mn transporter. Mn is crucial for bacterial survival in stressful environments, but is toxic in excess. Thus, Mn transport is tightly controlled at multiple levels to maintain optimal Mn levels. The small protein MntS adds a new level of regulation for Mn transporters, beyond the known transcriptional and post-transcriptional control. We also found that MntS binds to itself in the presence of Mn, providing a possible mechanism of downregulating MntS activity to terminate its inhibition of MntP Mn export. MntS is homologous to the signal peptide of SitA, the periplasmic metal-binding subunit of a Mn importer. Remarkably, the homologous signal peptide regions can substitute for MntS, demonstrating a functional relationship between MntS and these signal peptides. Conserved gene-neighborhoods support that MntS evolved from an ancestral SitA, acquiring a life of its own with a distinct function in Mn homeostasis.SignificanceThis study demonstrates that the MntS small protein binds and inhibits the MntP Mn exporter, adding another layer to the complex regulation of Mn homeostasis. MntS also interacts with itself in cells with Mn, which could prevent it from regulating MntP. We propose that MntS and other small proteins might sense environmental signals and shut off their own regulation via binding to ligands (e.g., metals) or other proteins. We also provide evidence that MntS evolved from the signal peptide region of the Mn importer, SitA. Homologous SitA signal peptides can recapitulate MntS activities, showing that they have a second function beyond protein secretion. Overall, we establish that small proteins can emerge and develop novel functionalities from gene remnants.
Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
Authors: Díaz Roberto Efraín , Ecker Andrew K. , Correy Galen J. , Asthana Pooja , Young Iris D. , Faust Bryan , Thompson Michael C. , Seiple Ian B. , Van Dyken Steven J. , Locksley Richard M. , Fraser James S. 
Published: June 2023

AbstractChitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We measured kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high resolution crystal structures of mAMCase in complex with oligomeric GlcNAcn, the building block of chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation.
The ghrelin receptor GHSR has two efficient agonists in an ancient fish species
Authors: Li Hao-Zheng , Wang Ya-Fen , Zheng Yong-Shan , Liu Ya-Li , Xu Zeng-Guang , Guo Zhan-Yun 
Published: June 2023

AbstractThe gastric peptide ghrelin and its receptor GHSR have important functions in energy metabolism. Recently, liver-expressed antimicrobial peptide 2 (LEAP2) was identified as an endogenous antagonist for GHSR. Ghrelin, LEAP2, and GHSR are ubiquitously present from fishes to mammals and are highly conserved in evolution. However, our recent study suggested that GHSRs from the Actinopterygii fishDanio rerio(zebrafish) andLarimichthys crocea(large yellow croaker) have lost their binding to ghrelin, despite binding normally to LEAP2. Do these fish GHSRs use another peptide as their agonist? To answer this question, in the present study, we tested to two fish motilins that are closely related to ghrelin. In ligand binding and activation assays, the fish GHSRs fromD. rerioandL. croceadisplayed no detectable or very low binding to all tested motilins; however, the GHSR from the Sarcopterygii fishLatimeria chalumnae(coelacanth) bound to its motilin with high affinity and was efficiently activated by it. Therefore, it seemed that motilin is not a ligand for GHSR inD. rerioandL. crocea, but is an efficient agonist for GHSR inL. chalumnae, which is known as a ‘living fossil’ and is believed to be one of the closest fish ancestors of tetrapods. The results of present study suggested that in ancient fishes, GHSR had two efficient agonists, ghrelin and motilin; however, this feature might be only preserved in some extant fishes with ancient evolutionary origins. Our present work shed new light on the ligand usage of GHSR in different fish species and in evolution.
Mutant Huntingtin impairs neurodevelopment in human brain organoids through CHCHD2-mediated neurometabolic failure
Authors: Lisowski Pawel , Lickfett Selene , Rybak-Wolf Agnieszka , Le Stephanie , Dykstra Werner , Mlody Barbara , Menacho Carmen , Roth Philipp , Richter Yasmin , Kulka Linda A. M. , Glazar Petar , Wu Haijia , Meierhofer David , Legnini Ivano , Otto Max , Miller Duncan , Neuendorf Nancy , Hahn Tobias , Telugu Narasimha Swamy , Böddrich Annett , Mayatepek Ertan , Diecke Sebastian , Olzscha Heidi , Kirstein Janine , Kühn Ralf , Cambridge Sidney , Rajewsky Nikolaus , Wanker Erich E. , Priller Josef , Metzger Jakob J. , Prigione Alessandro 
Published: June 2023

AbstractExpansion of the glutamine tract (poly-Q) in the protein Huntingtin (HTT) causes the neurodegenerative disorder Huntington’s disease (HD). Emerging evidence suggests that mutant HTT (mHTT) disrupts brain development. To gain mechanistic insights into the neurodevelopmental impact of human mHTT, we engineered induced pluripotent stem cells to introduce a biallelic or monoallelic mutant 70Q expansion or to remove the poly-Q tract of HTT. 70Q introduction caused aberrant development of cerebral organoids with loss of neural progenitor organization. The early neurodevelopmental signature of mHTT highlighted the dysregulation of the protein coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2), a transcription factor involved in mitochondrial integrated stress response. CHCHD2 repression was associated with abnormal mitochondrial morpho-dynamics and elevated resting energy expenditure. Elimination of the poly-Q tract of HTT normalized CHCHD2 expression and mitochondrial defects. Hence, mHTT-mediated disruption of human neurodevelopment is paralleled by aberrant neurometabolic programming mediated by dysregulation of CHCHD2, which could then serve as an early intervention target for HD.
A Pumpless, High-Throughput Microphysiological System Confirms Enteric Innervation of Duodenal Epithelium Strengthens the Barrier Function
Authors: Nichols Kyla N. , Snyder Jessica R. , Koppes Ryan A. , Koppes Abigail N. 
Published: June 2023

AbstractEnteric neurons, diverse in function and great in number, are heavily involved in homeostasis within the small intestine and their dysregulation has been implicated in gastrointestinal disorders and neurodegenerative diseases. Innovations in biofabrication have resulted in advances for in vitro models of the gut, however the majority lack enteric innervation, limiting therapeutic screening and discovery. Here, we present a high-throughput co-cultured microphysiological system (MPS), or organ chip, that supports a primary epithelial monolayer that directly interfaces with a three-dimensional hydrogel containing a primary enteric neuron culture, mimicking the close proximity present in vivo. The acrylic MPS device was fabricated with our established and cost-effective laser cut and assemble method. We have expanded this technology to include up to twelve 3D MPSs per device within the footprint of a traditional well-plate, supporting high-throughput experimentation. The inclusion of this 3D microtissue does not hinder physiologically relevant flow, standard measures of barrier function, and microscopy techniques. The device features gravity-driven flow to induce physiological shear stress on the epithelium culture and provide continuous nutrient presentation. Results show the intestinal and neural tissue maintained expected morphologies over an experimental timeline of ten days. Proximal enteric neurons extend neurites through the 3D hydrogel towards the epithelial monolayer. Barrier function was confirmed with both Transepithelial Electrical Resistance (TEER) and Lucifer Yellow diffusion on-chip. TEER confirmed a significantly more substantial barrier integrity in co-cultures compared to baseline values (1.25-fold) in epithelial cell-only. Lucifer yellow permeability assays performed in parallel supported the TEER results, with an 11.8% lower permeability of the co-cultured group than the epithelium only. The presence of the ENS on chip results in a significant (1.4 fold) reduction in epidermal growth factor (EGF). This is the first high-throughput, innervated gut on a chip device that demonstrates the importance of the autonomic nervous system on EGF expression and possibly epithelial renewal in vitro. Innervation is essential to create more biomimetic and physiologically relevant in vitro models for biological and pharmacological assays.
Persistent biofluid small molecule alterations induced byTrypanosoma cruziinfection are not restored by antiparasitic treatment
Authors: Dean Danya A. , Roach Jarrod , vonBargen Rebecca Ulrich , Xiong Yi , Kane Shelley S. , Klechka London , Wheeler Kate , Sandoval Michael Jimenez , Lesani Mahbobeh , Hossain Ekram , Katemauswa Mitchelle , Schaefer Miranda , Harris Morgan , Barron Sayre , Liu Zongyuan , Pan Chongle , McCall Laura-Isobel 
Published: June 2023

AbstractTable of contents graphicChagas Disease (CD), caused byTrypanosoma cruzi (T. cruzi)protozoa, is a complicated parasitic illness with inadequate medical measures for diagnosing infection and monitoring treatment success. To address this gap, we analyzed changes in the metabolome ofT. cruzi-infected mice via liquid chromatography tandem mass spectrometry analysis of clinically-accessible biofluids: saliva, urine, and plasma. Urine was the most indicative of infection status, across mouse and parasite genotypes. Metabolites perturbed by infection in the urine include kynurenate, acylcarnitines, and threonylcarbamoyladenosine. Based on these results, we sought to implement urine as a tool for assessment of CD treatment success. Strikingly, it was found that mice with parasite clearance following benznidazole antiparasitic treatment had comparable overall urine metabolome to mice that failed to clear parasites. These results match with clinical trial data in which benznidazole treatment did not improve patient outcomes in late-stage disease. Overall, this study provides insights into new small molecule-based CD diagnostic methods and a new approach to assess functional treatment response.
Evaluating the Performance of the Astral Mass Analyzer for Quantitative Proteomics Using Data Independent Acquisition
Authors: Heil Lilian R. , Damoc Eugen , Arrey Tabiwang N. , Pashkova Anna , Denisov Eduard , Petzoldt Johannes , Peterson Amelia C. , Hsu Chris , Searle Brian C. , Shulman Nicholas , Riffle Michael , Connolly Brian , MacLean Brendan X. , Remes Philip M. , Senko Michael W. , Stewart Hamish I. , Hock Christian , Makarov Alexander A. , Hermanson Daniel , Zabrouskov Vlad , Wu Christine C. , MacCoss Michael J. 
Published: June 2023

AbstractWe evaluate the quantitative performance of the newly released Asymmetric Track Lossless (Astral) analyzer. Using data independent acquisition, the Thermo Scientific™ Orbitrap™ Astral™ mass spectrometer quantifies 5 times more peptides per unit time than state-of-the-art Thermo Scientific™ Orbitrap™ mass spectrometers, which have long been the gold standard for high resolution quantitative proteomics. Our results demonstrate that the Orbitrap Astral mass spectrometer can produce high quality quantitative measurements across a wide dynamic range. We also use a newly developed extra-cellular vesicle enrichment protocol to reach new depths of coverage in the plasma proteome, quantifying over 5,000 plasma proteins in a 60-minute gradient with the Orbitrap Astral mass spectrometer.
Social media celebrities' influence on youths' diet behaviors: a gender study based on the AIDA marketing communication model
Authors: Wong Ivan Ho San , Fan Chi Man , Chiu Dickson K.W. , Ho Kevin K.W. 
Published: June 2023

PurposeSocial media celebrities are getting popular in promotions, and more people have experienced social media to receive information on diet and health tips. This research presents a study showing how social media can influence young people's diet behavior through collaboration with social media celebrities.Design/methodology/approachThrough recruiting on various social media and online education forums, this research recruited 196 young Hongkongers to participate in an online survey developed based on the AIDA (Action, Interest, Desire, Attention) marketing communication model on how youths access diet information from social media celebrities in Hong Kong.FindingsHong Kong youths consume diet information from social media celebrities through instant messaging systems, social networking sites and online videos, and, in particular, information on food calories and nutrition. However, sponsorship from vendors would decrease their desire to agree with the messages from social media celebrities. After receiving this information, some participants would follow tips and guides from social media celebrities. However, they seldom share such information. Interestingly, males are more willing to follow these tips and guides.Originality/valueFirst, this study fills the gap of prior research, which did not study much on how social media celebrities contribute to diet promotion to youths in Asia. Second, through the AIDA Model, this study shows how social media can affect the awareness and accessibility of diet information by young Hongkongers, followed by initiating their interest in this topic and retrieving more relevant information. Furthermore, the authors further understand their desire to follow and improve their behavior as promoted by social media influencers and how they practice such behavior. Based on these findings, health-related brands could consider using social media influencers helping to promote their products and services, and these brands could further use social media to secure customer engagement.
Struggling or juggling: work-life balance challenges of Western self-initiated women expatriates in the United Arab Emirates
Authors: Tahir Rizwan 
Published: June 2023

PurposeThis qualitative study is grounded on in-depth interviews with 30 Western women self-initiated expatriate (SIEs) currently living and working in the UAE. When selecting the interviewees, the author used purposeful sampling to ensure a diverse sample of interviewees with respect to nationality, age, gender and occupation.Design/methodology/approachThe present study, drawing on boundary theory, aims to investigate the work–life balance (WLB) of Western women SIEs regarding how these women construct and manage the borders between the non-work and work lives in the United Arab Emirates (UAE).FindingsThe results demonstrate that women SIEs experience conflicts and enrichment during overseas employment. Both directions – the impact flowing from working life to personal life and vice versa – were significant. Different career and life phases appeared to be crucial to these experiences. The study also found that some women SIEs in the UAE experience high pressure in the WLB approaches, which are primarily impacted by the specific work–life environment in the UAE. Mostly, work–life boundaries are culturally and socially induced. Hence, many women SIEs encounter disparities between the robust work–life separations in the home country compared to the host country; women SIEs, therefore, need to relax the boundaries to adapt to the competitive work–life environment in the UAE.Originality/valueThe present study contributes to research on work–life boundary management approaches in local settings, such as UAE, by analyzing cross-cultural and individual dimensions. Moreover, although women are still a minority among SIEs, the number of women is increasing. As prior studies have mainly focused on male SIEs, more research is required focusing specifically on women with overseas jobs. The present study endeavors to fill this research gap.