bluuebunny/crossref_metadata_2025 huggingface dataset:
TRPV4 couples with NCX1 to mediate glucose‐dependent glucagon‐like peptide‐1 release and improve glucose homeostasis
Authors: Chen Xiongying , Chu Fenglan , Sunchen Sijin , Li Junhui , Zhang Mengting , Xu Feng , Dong Hui
Published: November 2024

Although glucose, as a secretagogue of intestinal hormone, can stimulate glucagon‐like peptide 1 (GLP‐1) release, it has not been fully elucidated how glucose triggers GLP‐1 release from enteroendocrine cells (EECs). Here, we investigated the regulatory mechanisms of glucose‐induced Ca2+‐dependent GLP‐1 release from EECs. STC‐1 cells that possess many features of native intestinal EECs were used. The expression of TRPV4 channels and Na+/Ca2+ exchanger 1 (NCX1) in STC‐1 was analysed by immunocytochemistry. Calcium and sodium imaging, and patch clamp were applied, and GLP‐1 was detected using quantitative PCR, western blot and enzyme‐linked immunosorbent assays. Glucose markedly induced Na+ and Ca2+ signalling in STC‐1 cells. The glucose‐induced Ca2+ signalling was significantly attenuated by selective blockers of the voltage‐gated Ca2+ channels (VGCC), ryanodine receptors and InsP3 receptors. Most importantly, glucose‐induced Ca2+ signalling was significantly attenuated by the selective blockers of TRPV4 and NCX1. Moreover, the physical and functional couplings of TRPV4 and NCX1 were demonstrated in STC‐1 cells, and they promoted glucose‐mediated Ca2+ signalling to upregulate expression and release of GLP‐1 via Ca2+‐sensitive PKCα. Finally, the selective TRPV4 activator improved glucose tolerance in an oral glucose tolerance test in mice, but the selective blockers of TRPV4 and NCX1 attenuated glucose‐induced intestinal GLP‐1 release. We demonstrate a coupling of TRPV4 and NCX1 in EECs to regulate glucose‐stimulated intestinal GLP‐1 release via a novel TRPV4/NCX1/Ca2+/PKCα axis. Targeting this axis may provide new therapeutic potentials for glycometabolic diseases.

image

Key points

Glucagon‐like peptide 1 (GLP‐1) secreted primarily from intestinal L cells in response to meals plays a critical role in maintaining glucose homeostasis.

Physical and functional couplings of TRPV4 and NCX1 are pivotal in glucose‐stimulated GLP‐1 release via a novel TRPV4/NCX1/Ca2+/PKCα axis.

Since this axis is involved in glucose homeostasis, our findings may provide new potential drug targets for prevention/treatment of glycometabolic diseases.
Integrated responses of the SIP syncytium generate a major motility pattern in the colon
Authors: Koh Sang Don , Lee Ji Yeon , Ryoo Seung‐Bum , Drumm Bernard T. , Kim Hyun Jin , Baker Sal A. , Sanders Kenton M.
Published: November 2024

The peristaltic reflex has been a central concept in gastrointestinal motility; however, evidence was published recently suggesting that post‐stimulus responses that follow inhibitory neural responses provide the main propulsive force in colonic motility. This new concept was based on experiments on proximal colon where enteric inhibitory neural inputs are mainly nitrergic. However, the nature of inhibitory neural inputs changes from proximal to distal colon where purinergic inhibitory regulation dominates. In spite of the transition from nitrergic to purinergic regulation, post‐stimulus responses and propulsive contractions were both blocked by antagonists of a conductance (ANO1) exclusive to interstitial cells of Cajal (ICC). How purinergic neurotransmission, transduced by PDGFRα+ cells, can influence ANO1 in ICC is unknown. We compared neural responses in proximal and distal colon. Post‐stimulus responses were blocked by inhibition of nitrergic neurotransmission in proximal colon, but P2Y1 receptor antagonists were more effective in distal colon. Ca2+ entry through voltage‐dependent channels (CaV3) enhances Ca2+ release in ICC. Thus, we reasoned that hyperpolarization caused by purinergic responses in PDGFRα+ cells, which are electrically coupled to ICC, might decrease inactivation of CaV3 channels and activate Ca2+ entry into ICC via anode‐break upon cessation of inhibitory responses. Post‐stimulus responses in distal colon were blocked by MRS2500 (P2Y1 receptor antagonist), apamin (SK channel antagonist) and NNC55‐0396 (CaV3 antagonist). These compounds also blocked propagating contractions in mid and distal colon. These data provide the first clear demonstration that integration of functions in the smooth muscle–ICC–PDGFRα+ cell (SIP) syncytium generates a major motility behaviour.

image

Key points

Propagating propulsive contractions initiated by the enteric nervous system are a major motility behaviour in the colon. A major component of contractions, necessary for propulsive contractions, occurs at cessation of enteric inhibitory neurotransmission (post‐stimulus response) and is generated by interstitial cells of Cajal (ICC), which are electrically coupled to smooth muscle cells.

The nature of enteric inhibitory neurotransmission shifts from proximal colon, where it is predominantly due to nitric oxide, to distal colon, where it is predominantly due to purine neurotransmitters.

Different cells transduce nitric oxide and purines in the colon. ICC transduce nitric oxide, but another type of interstitial cell, PDGFRα+ cells, transduces input from purinergic neurons.

However, the post‐stimulus responses in proximal and distal colon are still generated in ICC.

This paper explores how integrated behaviours of ICC, PDGFRα+ cells and smooth muscle cells accomplish propulsive motility in the colon.
Maladaptive cardiomyocyte calcium handling in adult offspring of hypoxic pregnancy: protection by antenatal maternal melatonin
Authors: Lock Mitchell C. , Patey Olga V. , Smith Kerri L. M. , Niu Youguo , Jaggs Ben , Trafford Andrew W. , Giussani Dino A. , Galli Gina L. J.
Published: November 2024

Chronic fetal hypoxia is one of the most common complications of pregnancy and can programme cardiac abnormalities in adult offspring including ventricular remodelling, diastolic dysfunction and sympathetic dominance. However, the underlying mechanisms at the level of the cardiomyocyte are unknown, preventing the identification of targets for therapeutic intervention. Therefore, we aimed to link echocardiographic data with cardiomyocyte function to reveal cellular mechanism for cardiac dysfunction in rat offspring from hypoxic pregnancy. Further, we investigated the potential of maternal treatment with melatonin as antenatal antioxidant therapy. Wistar rats were randomly allocated into normoxic (21% O2) or hypoxic (13% O2) pregnancy with or without melatonin treatment (5 µg/ml; normoxic melatonin in the maternal drinking water from gestational day 6 to 20 (term = 22 days). After delivery, male and female offspring were maintained to adulthood (16 weeks). Cardiomyocytes were isolated from the left and right ventricles, and calcium (Ca2+) handling was investigated in field‐stimulated myocytes. Systolic and diastolic function was negatively impacted in male and female offspring of hypoxic pregnancy demonstrating biventricular systolic and diastolic dysfunction and compensatory increases in cardiac output. Ca2+ transients from isolated cardiomyocytes in offspring of both sexes in hypoxic pregnancy displayed diastolic dysfunction with a reduced rate of [Ca2+]i recovery. Cardiac and cardiomyocyte dysfunction in male and female adult offspring was ameliorated by maternal antenatal treatment with melatonin in hypoxic pregnancy. Therefore, cardiomyocyte Ca2+ mishandling provides a cellular mechanism explaining functional deficits in hearts of male and female offspring in pregnancies complicated by chronic fetal hypoxia.

image

Key points

This study identified significant changes in Ca2+ handling within cardiomyocytes isolated from offspring of hypoxic pregnancy including reduced systolic Ca2+ transients, impaired diastolic recovery of [Ca2+]i and a greater increase in systolic [Ca2+]i amplitude to β‐adrenergic stimulation.

These changes in cardiomyocyte Ca2+ handling help to explain dysregulation of biventricular systolic and diastolic dysfunction determined by echocardiography.

The data show protection against maladaptive cardiomyocyte calcium handling and thereby improvement in cardiac function in adult offspring of hypoxic pregnancy treated with melatonin with doses lower than those recommended for overcoming jet lag in humans.

Melatonin treatment alone in healthy pregnancy did cause some alterations in cardiac structure. Therefore, maternal treatment with melatonin should only be given to pregnancies affected by chronic fetal hypoxia.
Forecasting High Cycle and Very High Cycle Fatigue Through Enhanced Strain-Energy Based Fatigue Life Prediction
Authors: Celli Dino , Sheridan Luke , George Tommy , Warner Justin , Smith Lucas
Published: November 2024

This study applies a novel strain-energy based fatigue life prediction method to low cycle fatigue (LCF) data additive manufactured (AM) Inconel 718 round dog-bones, specifically focusing on cycles to failure less than 105. The objective is to forecast high cycle fatigue (HCF, 106–107) and very high cycle fatigue (VHCF >107), aiming to approximate stress versus cycles to failure (SN) behavior and the inherent variability in the fatigue life of the material system. This tool is motivated by the need to characterize an expanding and diverse array of materials produced by additive manufacturing methods, process parameter modifications, and optimizations, which can significantly impact fatigue life and overall structural reliability. The fatigue life prediction method achieves this by generating a fatigue life distribution as a function of stress amplitude. Bayesian statistical inference and stochastic sampling techniques are employed iteratively for each test data point, incorporating stress, cycles to failure, and total strain-energy dissipated leading to fatigue failure. Experimental LCF fatigue data are acquired using a standard axial servohydraulic load frame equipped with an axial extensometer for strain and strain-energy data collection. HCF and VHCF data is generated utilizing an ultrasonic fatigue test frame capable of cycling at 20 kHz. The fatigue data obtained from both servohydraulic and ultrasonic fatigue testing are presented and compared. The energy-based fatigue life prediction framework, utilizing only LCF data, is deployed to forecast HCF and VHCF fatigue behavior for AM Inconel 718 fatigue. The HCF and VHCF data generated are then used to validate the forecasts generated from the novel energy-based fatigue life prediction method. Comparisons are made against Random Fatigue Limit curve estimations to assess the effectiveness and accuracy of the proposed methodology.
Effects of Prematch Travel and Training on Physical and Technical Performance in International Football Matches
Authors: Clements Ewan , Ehrmann Fabian , Clark Andrew , Jones Mark , McCall Alan , Duffield Rob
Published: November 2024

Purpose: This study examined the relationship of prematch travel and in-camp training on ensuing physical and technical match performance of footballers (soccer) competing for a national team. Methods: Match running and technical performance data were obtained from 68 national-team footballers competing in international matches (N = 108). Match performance data were aligned with the confirmed travel durations, time-zone change, travel direction, and time between arrival and kickoff for the travel to the match. In addition, in-camp training load from the 3 days prior to national-team matches was also collated. Linear mixed models assessed relationships between travel and training measures with physical and technical match performance outcomes. Results: Travel variables explained little variance in outcomes (R2 = .02–.16). Traveling eastward was associated with an increase in total (P = .042) and very high-speed distance (P = .030) in matches and a 5% decrease in pass accuracy (P = .012). Greater time-zone difference was associated with increased match decelerations (P = .027), while arriving later for matches was associated with increased total (P = .041) tackles. Increases in training high-speed distance were associated with increases in match high-speed distance (P = .004) and number of decelerations (P < .001). An increase in training total distance was associated with a decrease in match decelerations (P = .002). Conclusions: Prematch travel appeared to have minimal effects on physical and technical performance in this national team. Training loads prior to matches may have some relationship with match running performance, and, thus, readiness to train should be a priority for athletes arriving in national-team camps.
Coaching Behaviors in Goalball: Perceptions of Athletes With Visual Impairments
Authors: De Luna-Vazquez Wellington , Shapiro Deborah R. , Moreno Anthony
Published: November 2024

Goalball is a Paralympic team sport designed specifically for people with visual impairments. This study aimed to investigate goalball athletes’ perceptions of the coaching behaviors of their coaches. A total of 35 goalball athletes (12 female, 23 male) participated in the study, completing the Coaching Behavior Scale for Sport comprised of 47-items across seven constructs: physical training and conditioning, technical skills, mental preparation, goal setting, competition strategies, personal rapport, and negative personal rapport. Descriptive statistics for each subscale were calculated across different demographic groups. Negative personal rapport had the highest mean among all constructs (M = 6.30, SD = .59) and goal setting being the lowest (M = 4.32, SD = 1.64). A Mann–Whitney U test compared mean differences between age, gender, training frequency, and prior coaching experience. No statistically significant differences were found between groups. The findings showed positive perceptions toward coaches’ behaviors, with frequent engagement identified in areas of personal rapport, competition strategies, and technical skills. However, athletes perceived physical training and goal setting as areas of less involvement from their coaches. This suggests a disconnection in coaches’ engagement with athletes’ objective-setting processes and physical preparation. Future research directions and limitations were also discussed.
Understanding Parental Involvement in Irish Dance
Authors: Rouquette Olivier Y. , Cahalan Róisín , Knight Camilla J.
Published: November 2024

The overall aim of the present study was to understand how dancers’ perception and parents’ own perceptions of parents’ responsiveness and competence support were associated with dancers’ self-perceptions and thriving. In total, 64 dancers and 91 parents for a total of 52 matching dyads participated in the study. Dancers were aged 7–24 years, trained on average 4.17 times/weeks, and were involved in Irish dancing for an average of 9.71 years. Participants completed self-reported questionnaires assessing their perceived responsiveness, competence support, self-perceptions, and thriving. Main analyses consisted of mediations performed with structural equation modeling. Results demonstrate that dancers’ perceptions of their parents’ responsiveness and competence support are associated with their self-perceptions and thriving. Responsiveness and competence support of their second parent was more strongly associated with thriving than responsiveness and competence support of the main parent. Parents’ own perceptions of competence support were positively associated with dancers’ thriving.
How Medial Tibial Stress Syndrome Is Affected by Alignment, Range of Motion, Strength, and Gait Biomechanics: A Systematic Review and Meta-Analysis
Authors: Lee Inje , Jeon Hyung Gyu , Ha Sunghe , Jeong Heeseong , Lee Sae Yong
Published: November 2024

Context: Medial tibial stress syndrome (MTSS) is a common chronic injury of the lower-extremity in the physically active population. However, the risk factors for MTSS remain unclear. Objective: This study identified the risk factors for MTSS and established the continuum model of lower-extremity alignments, range of motion, muscular strength, and gait kinematics affecting each other and MTSS development. Evidence Acquisition: Online databases including PubMed, CINAHL, SPORTDiscus, and Web of Science were used to retrieve studies related to risk factors for MTSS. The study eligibility criteria were studies that used the MTSS definition of the Yates and White criteria, or included participants with MTSS, except for stress fracture and compartment syndrome. A total of 2099 papers were retrieved during the initial search stage. After screening, based on eligibility criteria and cross-reference, 21 papers were included in this study. Data on lower-extremity alignments, range of motion, muscular strength, and gait biomechanics were extracted as outcome variables for this meta-analysis. Publication bias was assessed using funnel plots and Egger’s regression analysis. Evidence Synthesis: Foot posture index (standardized mean difference [SMD] = 1.23; 95% CI, 0.02–2.43), intercondylar interval (SMD = 0.29; 95% CI, 0.10–0.48), inversion range of motion (SMD = 0.37; 95% CI, 0.10–0.63), eversion strength (SMD = 0.37; 95% CI, 0.10–0.65), and dynamic arch height change during walking (SMD = 1.05; 95% CI, 0.49–1.60) were significant risk factors for MTSS. Egger’s regression analysis revealed asymmetry in several variables, which indicates publication bias. The trim-and-fill method was applied to these variables. A comparison between the SMD and adjusted SMD showed that the variables had minimal impacts on the meta-analysis. Conclusions: Based on our results, health care professionals should assess the significant risk factors in patients before participation in physical activities and treat them to prevent and rehabilitate MTSS.
Comparing Vibration Foam Rolling and Static Stretching for Enhancing Muscle Recovery in Professional Male Soccer Players: A Counterbalanced Crossover Study
Authors: Corredoira Francisco J. , Lorenzo-Martínez Miguel , Carrera Samuel , Costa Pablo B. , Rey Ezequiel
Published: November 2024

Context: Professional soccer players frequently experience fatigue due to the demanding nature of the sport. In this context, effective recovery strategies are essential for maintaining performance. Static stretching (SS) is commonly used in soccer, but its efficacy is debated. Vibration foam rolling (VFR) is a novel recovery technique that has not been extensively studied in soccer. Objective: This research aimed to investigate the acute effects of VFR (3 sets of 45 s of rolling and 15 s of rest between sets) and SS (3 sets of 45 s and 15 s of rest between sets) on muscle contractile properties in professional soccer players. Design: Eighteen players participated in this counterbalanced crossover study. Settings: After a 1-week washout period between sessions, the subjects completed the 2 condition trials (VFR or SS) in counterbalanced order following a training session, which had a duration of 77 min and a total distance of 6500 m covered. Main Outcome Measures: Muscle contractile properties of the rectus femoris were assessed with tensiomyography before training (pre), immediately after training (post 1), and postrecovery intervention (post 2). Tensiomyography parameters included maximal radial muscle-belly displacement and contraction time and velocity. Data were analyzed using repeated-measures analysis of variance. Results: There were no significant differences in the training load between groups during the training sessions (P > .05). Results showed that maximal radial muscle-belly displacement (P = .004) and contractiontime (P = .007) significantly decrease from pre (before training) to post 1 (after training). No significant main effects for group were obtained for all the variables (P > .05). However, both VFR and SS interventions effectively restored maximal radialmuscle-belly displacement (P = .011) and contraction time (P = .008) from post 1 (after) to post 2 (postrecovery intervention), suggesting reduced muscular stiffness. Contraction velocity remained unchanged after both interventions (P > .05). Conclusions: Therefore, these interventions could offer valuable advantages for posttraining neuromuscular acute recovery in professional soccer players.
Hemochromatosis neural archetype reveals iron disruption in motor circuits
Authors: Loughnan Robert , Ahern Jonathan , Boyle Mary , Jernigan Terry L. , Hagler Donald J. , Iversen John R. , Frei Oleksandr , Smith Diana M. , Andreassen Ole , Zaitlen Noah , Sugrue Leo , Thompson Wesley K. , Dale Anders , Schork Andrew J. , Fan Chun Chieh
Published: November 2024

Our understanding of brain iron regulation and its disruption in disease is limited. Excess iron affects motor circuitry, contributing to Parkinson’s disease (PD) risk. The molecular mechanisms regulating central iron levels, beyond a few well-known genes controlling peripheral iron, remain unclear. We generated scores based on the archetypal brain iron accumulation observed in magnetic resonance imaging scans of individuals with excessive dietary iron absorption and hemochromatosis risk. Genome-wide analysis revealed that this score is highly heritable, identifying loci associated with iron homeostasis, and driven by peripheral iron levels. Our score predicted gait abnormalities and showed a U-shaped relationship with PD risk, identifying individuals with threefold increased risk. These results establish a hormetic relationship between brain iron and PD risk, where central iron levels are strongly determined by genetics via peripheral iron. This framework combining forward and reverse genetics is a powerful study design to understand genomic drivers underlying high dimensional phenotypes.
Acoustic virtual 3D scaffold for direct-interacting tumor organoid–immune cell coculture systems
Authors: Shan Han , Chen Maike , Zhao Shuang , Wei Xiongwei , Zheng Mingde , Li Yixin , Lin Qibo , Jiang Zixi , Chen Ziyan , Fei Chunlong , Li Zhaoxi , Chen Zeyu , Chen Xiang
Published: November 2024

Three-dimensional (3D) cell culture has revolutionized life sciences, particularly in organoid technologies. Traditional bioscaffold materials, however, complicate the detachment of tumor organoids and hamper the routine use of organoid–immune cell cocultures. Here, we show an acoustic virtual 3D scaffold (AV-Scaf) method to achieve 3D tumor organoid culture, enabling a direct-interacting tumor organoid–immune cell coculture system. The self-organization process of tumor cells is facilitated by a vortex acoustic field, which enables the cell bioassembly and ion channel activation. This approach can significantly enhance the influx of calcium ions, thereby accelerating intercellular interactions of cellular assemblies. We established scaffold-free melanoma and breast cancer organoids using AV-Scaf and cocultured melanoma organoids with T cells. We found that our coculture system resulted in a high activation state of T cells, characterized by notable up-regulation of granzyme B (2.82 to 17.5%) and interferon-γ (1.36 to 16%). AV-Scaf offers an efficient method for tumor organoid–immune cell studies, advancing cancer research and immunotherapy development.
GGNBP2 regulates MDA5 sensing triggered by self double-stranded RNA following loss of ADAR1 editing
Authors: Heraud-Farlow Jacki E. , Taylor Scott R. , Chalk Alistair M. , Escudero Adriana , Hu Shi-Bin , Goradia Ankita , Sun Tao , Li Qin , Nikolic Iva , Li Jin Billy , Fidalgo Miguel , Guallar Diana , Simpson Kaylene J. , Walkley Carl R.
Published: November 2024

Adenosine-to-inosine (A-to-I) editing of double-stranded RNA (dsRNA) by ADAR1 is an essential modifier of the immunogenicity of cellular dsRNA. The role of MDA5 in sensing unedited cellular dsRNA and the downstream activation of type I interferon (IFN) signaling are well established. However, we have an incomplete understanding of pathways that modify the response to unedited dsRNA. We performed a genome-wide CRISPR screen and showed that GGNBP2, CNOT10, and CNOT11 interact and regulate sensing of unedited cellular dsRNA. We found that GGNBP2 acts between dsRNA transcription and its cytoplasmic sensing by MDA5. GGNBP2 loss prevented induction of type I IFN and autoinflammation after the loss of ADAR1 editing activity by modifying the subcellular distribution of endogenous A-to-I editing substrates and reducing cytoplasmic dsRNA load. These findings reveal previously undescribed pathways to modify diseases associated with
ADAR
mutations and may be determinants of response or resistance to small-molecule ADAR1 inhibitors.
Interaction of the
Wolbachia
surface protein with a novel pro-viral protein from
Aedes aegypti
Authors: Hussain Mazhar , Qi Zhi , Asgari Sassan
Published: November 2024

Dengue virus (DENV) and other flaviviruses are prevented from replicating in mosquitoes by
Wolbachia
. To date, several reports have appeared that highlight multiple molecular and cellular pathways involved in the blocking mechanism, which underlines the complicated nature of the mechanism. Here, we developed a hypothesis on whether
Wolbachia
proteins interact with pro-viral host proteins by using a unique approach to study the antiviral mechanism based on
Wolbachia
-host protein-protein interaction. We selected
Wolbachia
surface protein (WSP) for co-immunoprecipitation because of its abundance and possible secretion. We first confirmed WSP’s secretion in mosquito cells and found two host proteins,
Ae. aegypti
serine-threonine kinase (STK) and synaptic vesicle membrane (SVM) protein VAT-1, and one
Wolbachia
protein (
w
GroEL) interacting with WSP. We examined the role of
STK
and
SVM
genes in relation to DENV replication in
Ae. aegypti
mosquitoes and mosquito cell lines with and without
Wolbachia
. In DENV-infected Aag2 cells, the expression of
SVM
and
STK
was significantly increased. However, although these genes were induced in
Wolbachia
-infected Aag2 cells, they were downregulated after DENV infection. Silencing of
STK
, but not
SVM
, reduced DENV replication in Aag2 cells and mosquitoes. Conversely, RNA activation of
STK
, by utilizing promoter induction via short activating oligos, resulted in higher DENV replication in
Wolbachia
-infected and uninfected cell lines. Overall, our findings suggest that
STK
is a pro-viral gene, and
Wolbachia
WSP binds to STK, possibly making it less accessible for DENV replication.

IMPORTANCE

Wolbachia
is an endosymbiotic bacterium that blocks the replication of arboviruses in transinfected
Aedes aegypti
mosquitoes. In this study, we focused on identifying the potential interaction of
Wolbachia
proteins with the host pro-viral proteins. For this, we embarked on identifying the interacting proteins with a major
Wolbachia
protein, WSP, which is both structural and also secreted into the host cells. An
Ae. aegypti
STK was identified, which is induced in DENV and
Wolbachia
-infected cells. Silencing or induction of the gene led to reduced and increased DENV replication
in vitro
. Consistently, knocking down the gene in mosquitoes resulted in decreased virus replication. We hypothesize that WSP may sequester STK, which is pro-viral, contributing to
Wolbachia
virus blocking.
The
Vibrio
type VI secretion system induces intestinal macrophage redistribution and enhanced intestinal motility
Authors: Ngo Julia S. , Amitabh Piyush , Sokoloff Jonah G. , Trinh Calvin , Wiles Travis J. , Guillemin Karen , Parthasarathy Raghuveer
Published: November 2024

Intestinal microbes, whether resident or transient, influence the physiology of their hosts, altering both the chemical and the physical characteristics of the gut. An example of the latter is the human pathogen
Vibrio cholerae’s
ability to induce strong mechanical contractions, discovered in zebrafish. The underlying mechanism has remained unknown, but the phenomenon requires the actin crosslinking domain (ACD) of
Vibrio
’s type VI secretion system (T6SS), a multicomponent protein syringe that pierces adjacent cells and delivers toxins. By using a zebrafish-native
Vibrio
and imaging-based assays of host intestinal mechanics and immune responses, we find evidence that macrophages mediate the connection between the T6SS ACD and intestinal activity. Inoculation with
Vibrio
gives rise to strong, ACD-dependent, gut contractions whose magnitude resembles those resulting from genetic depletion of macrophages.
Vibrio
also induces tissue damage and macrophage activation, both ACD-dependent, recruiting macrophages to the site of tissue damage and away from their unperturbed positions near enteric neurons that line the midgut and regulate intestinal motility. Given known crosstalk between macrophages and enteric neurons, our observations suggest that macrophage redistribution forms a key link between
Vibrio
activity and intestinal motility. In addition to illuminating host-directed actions of the widespread T6SS protein apparatus, our findings highlight how localized bacteria-induced injury can reshape neuro-immune cellular dynamics to impact whole-organ physiology.

IMPORTANCE

Gut microbes, whether beneficial, harmful, or neutral, can have dramatic effects on host activities. The human pathogen
Vibrio cholerae
can induce strong intestinal contractions, though how this is achieved has remained a mystery. Using a zebrafish-native
Vibrio
and live imaging of larval fish, we find evidence that immune cells mediate the connection between bacteria and host mechanics. A piece of
Vibrio
’s type VI secretion system, a syringe-like apparatus that stabs cellular targets, induces localized tissue damage, activating macrophages and drawing them from their normal residence near neurons, whose stimulation of gut contractions they dampen, to the damage site. Our observations reveal a mechanism in which cellular rearrangements, rather than bespoke biochemical signaling, drives a dynamic neuro-immune response to bacterial activity.
Genomic insights into the alphaproteobacterium
Georhizobium
sp. MAB10 revealed a pathway of Mn(II) oxidation-coupled anoxygenic photoautotrophy: a novel understanding of the biotic process in deep-sea ferromanganese nodule formation
Authors: Xu Xiuli , Zhang Litao , Song Fuhang , Zhang Guoliang , Ma Linlin , Yang Na
Published: November 2024

Under light conditions, Mn(II) facilitates the photoautotrophic growth of
Georhizobium
sp. MAB10, a strain derived from deep-sea ferromanganese nodules, along with the generation of dark Mn oxides (β-MnO
2
). This study investigated the genetic basis of Mn(II) oxidation-coupled anoxygenic photoautotrophy using genome sequencing and biochemical assays of strain MAB10. Preliminary results indicated the presence of genes encoding a functional pheophytin-quinone-type photosynthetic reaction center and a putative key enzyme for Mn(II) oxidation, namely FtsP/CotA-like multicopper oxidase GE001273. Under light conditions, Mn(II) significantly reduced the respiration rate and elevated the intracellular NADH/NAD
total
ratio. This suggested that Mn(II)-derived electrons entered the cyclic photophosphorylation, partially replacing the oxidative phosphorylation for ATP production and enhancing the electron flow to complex I for NADH generation.
In vitro
enzymatic studies confirmed that GE001273 was a catalyst for Mn(II) oxidation in the outer membrane. Comprehensive genomic analyses of respiration and carbon and nitrogen metabolism revealed the high ecophysiological flexibility of strain MAB10 during Mn(II) oxidation-coupled anoxygenic photoautotrophy in deep-sea habitats. These analyses provided insights into bacterial Mn(II) oxidation-coupled anoxygenic photoautotrophy during microorganism-mediated deep-sea ferromanganese nodule formation.

IMPORTANCE

Microorganisms are believed to participate in the biotic process of deep-sea ferromanganese nodule formation [Mn(II) oxidation]. Despite the multitude of studies and reviews focusing on the details of Mn(II) oxidation catalyzed by diverse heterotrophs, the mechanistic roles of manganese chemolithotrophs from ferromanganese nodules remain unclear. We demonstrate that strain
Georhizobium
sp. MAB10 can utilize Mn(II)-derived electrons for photoautotrophic growth, with concomitant generation of dark β-MnO
2
type Mn oxides under near-infrared light condition. This study uses genomic and biochemical assays to explore the genetic basis of Mn(II) oxidation-coupled anoxygenic photoautotrophy. The comprehensive analyses of respiration and carbon and nitrogen metabolism further elucidated the high ecophysiological flexibility of strain MAB10 in deep-sea habits. These findings expand our understanding of the role of chemolithotrophs in deep-sea ferromanganese nodule formation and justify further investigations into the molecular basis for Mn(II) oxidation-coupled anoxygenic photoautotrophy.
Overexpressing the ClpC AAA+ unfoldase accelerates developmental cycle progression in
Chlamydia trachomatis
Authors: Jensen Aaron A. , Firdous Saba , Lei Lei , Fisher Derek J. , Ouellette Scot P.
Published: November 2024

Chlamydia
is an obligate intracellular bacterium that undergoes a complex biphasic developmental cycle, alternating between the smaller, infectious, non-dividing elementary body (EB) and the larger, non-infectious but dividing reticulate body. Due to the differences between these functionally and morphologically distinct forms, we hypothesize protein degradation is essential to chlamydial differentiation. The bacterial Clp system, consisting of an ATPase unfoldase (e.g., ClpX or ClpC) and a proteolytic component (e.g., ClpP), is critical for the physiology of bacteria through its recognition, and usually degradation, of specific substrates. We observed by transmission electron microscopy that overexpression of wild-type ClpC, but not an ATPase mutant isoform, in
Chlamydia
increased glycogen accumulation within the vacuolar niche of the bacteria earlier in the developmental cycle than typically observed. This suggested ClpC activity may increase the expression of EB-associated genes. Consistent with this, targeted RT-qPCR analyses demonstrated a significant increase in several EB-associated gene transcripts earlier in development. These effects were not observed with overexpression of the ATPase mutant of ClpC, providing strong evidence that the activity of ClpC drives secondary differentiation. By analyzing the global transcriptional response to ClpC overexpression using RNA sequencing, we observed a shift to earlier expression of canonical late developmental cycle genes and other EB-associated genes. Finally, we directly linked overexpression of ClpC with earlier production of infectious chlamydiae. Conversely, disrupting normal ClpC function with an ATPase mutant caused a delay in developmental cycle progression. Overall, these findings provide the first mechanistic insight for initiation of secondary differentiation in
Chlamydia
.

IMPORTANCE

Chlamydia
species are obligate intracellular bacteria that require a host cell in which to complete their unique developmental cycle.
Chlamydia
differentiates between an infectious but non-replicating form, the elementary body, and a non-infectious but replicating form, the reticulate body. The signals that drive differentiation events are not characterized. We hypothesize that proteases are essential for mediating differentiation by allowing remodeling of the proteome as the organism transitions from one functional form to another. We previously reported that the
C
aseino
l
ytic
p
rotease (Clp) system is essential for chlamydial growth. Here, we reveal a surprising function for ClpC, an unfoldase, in driving production of infectious chlamydiae during the chlamydial developmental cycle.
Development of a metabolome-based respiratory infection prognostic during COVID-19 arrival
Authors: Robinson John I. , Marks Laura R. , Hinton Andrew L. , O'Halloran Jane A. , Goss Charles W. , Mucha Peter J. , Henderson Jeffrey P.
Published: November 2024

In a new respiratory virus pandemic, optimizing allocation of scarce medical resources becomes an urgent challenge. Infection prognosis takes on particular importance when allocating scarce antiviral antibodies and drugs, which are most effective when administered before the onset of severe disease. During arrival of the COVID-19 pandemic to the United States in 2020, we conducted a prognostic biomarker discovery and validation effort based upon metabolomic profiling with a liquid-chromatography-mass spectrometer (LC-MS) type used clinically for rapid toxicology. We obtained urine specimens from 163 patients presenting for evaluation. We obtained LC-MS profiles in the initial cohort and used machine learning methods to define a simplified urine metabolomic signature associated with respiratory failure or death by 90 days. This signature was composed of three metabotypes linked to intestinal microbiome metabolism and anticonvulsant use, with a receiver-operator characteristic area under the curve (ROC AUC) of 89.4%. Blinded application of this signature to the subsequent validation cohort yielded a ROC AUC of 81.2%. A model trained on the two baseline metabotypes present before intubation exhibited similar performance in the validation cohort. This study demonstrates the plausibility and promise of rapid metabolome-based prognostic discovery and validation in the opening wave of a pandemic. The approach used here could be used to inform therapeutic and resource allocation decisions early in a future epidemic.

IMPORTANCE

In a new respiratory virus pandemic, the ability to identify patients at greatest risk for severe disease is essential to direct scarce medical resources to those most likely to benefit from them. Tools to predict disease severity are best developed early in a pandemic, but laboratory-based resources to develop these may be limited by available technology and by infection precautions. Here, we show that an accessible metabolic profiling approach could identify a prognostic signature of severe disease in the initial wave of COVID-19, when patients presenting for care often exceeded the available doses of convalescent plasma and remdesivir. In a future pandemic, this approach, alongside efforts to identify clinical disease severity predictors, could improve patient outcomes and facilitate therapeutic trials by identifying individuals at high risk for severe disease.
Whole-genome sequence of
Psychrobacter
sp. strain AH5, isolated from salted bluespot mullet (
Valamugil seheli
)
Authors: Al-Harbi Ahmed H.
Published: November 2024

Herein is reported the whole-genome sequence of
Psychrobacter
sp. strain AH5 that was isolated from salted bluespot mullet (
Valamugil seheli
). The genome assembly comprises a total of 3,241,797 bp with a GC content of 43.73% and encodes 2,541 protein-coding genes.
Enhancing pathogens detection in suspected geriatric bloodstream infections using Nanopore-targeted sequencing
Authors: Zhao Menghui , Ouyang Yan , Mei Junchi , Liu Hang
Published: November 2024

Bloodstream infections (BSIs) are a critical concern for elderly patients, where prompt and accurate diagnosis is vital for effective treatment. Traditional blood culture methods suffer from delayed results and susceptibility to false-negatives. Nanopore-targeted sequencing (NTS) offers rapid pathogen detection and reporting, presenting a promising alternative. However, the application of NTS for diagnosing suspected BSIs in geriatric patients remains insufficiently studied. We conducted a retrospective cohort study from January 2022 to January 2024, including 198 geriatric patients suspected of BSIs. We utilized NTS to detect pathogen characteristics and compared the effectiveness and consistency of NTS with simultaneous blood culture testing for pathogen detection. NTS demonstrated a pathogen detection rate of 61.1%. The most common bacterial pathogens were
Escherichia coli
and
Staphylococcus aureus
(each 7.7%), while
Candida albicans
was the most prevalent fungal pathogen (30%). Mixed-bacterial infections were detected in 21.7% of NTS-positive cases, and concurrent bacterial–fungal infections were observed in 9.92% of these cases. NTS-positive patients had higher rates of comorbidities, elevated inflammatory markers, and worse prognoses compared to NTS-negative patients. NTS exhibited a significantly higher pathogen detection rate and faster turnaround time than blood culture (78.1% vs 42.2%,
P
< 0.001), with an agreement rate of 65.6%. The elderly BSI patients frequently involve multiple or mixed infections and correlate with poorer prognoses. NTS provides a faster and more sensitive diagnostic alternative to traditional blood culture, potentially improving clinical outcomes and guiding more effective treatment strategies. This study highlights the need for further research to validate the routine clinical integration of NTS for managing BSIs in geriatric populations.

IMPORTANCE

Bloodstream infections (BSIs) in elderly patients pose substantial diagnostic and therapeutic challenges due to the limitations of traditional blood culture methods, which are hampered by slow turnaround times and false-negatives. Nanopore-targeted sequencing (NTS) emerges as a significant advancement, offering rapid and accurate pathogen detection directly from blood samples. This study demonstrates that NTS provides a higher detection rate and faster results than conventional blood cultures, crucial for the timely management of BSIs in geriatric patients, who often present with multiple or mixed infections and have poorer clinical outcomes. The findings underscore the potential of NTS to enhance diagnostic accuracy and speed, informing more effective treatment strategies and improving overall patient outcomes. Further research is essential to establish NTS as a routine diagnostic tool in the clinical management of BSIs in the elderly.
Sedimentary record of oceanic plateau accretion: Revisiting the Eocene to Miocene stratigraphy of the northern Olympic Peninsula, Washington (USA)
Authors: Donaghy Erin E. , Eddy Michael P. , Ridgway Kenneth D. , Ickert Ryan B.
Published: November 2024

Oceanic plateaus are common in modern oceanic basins and will ultimately collide with continental subduction zones. Despite the frequency of these events, complete sedimentary records of oceanic plateau collision and accretion have remained limited to only a few Cenozoic examples with excellent exposure and tectonic context. Our study focuses on building a stratigraphic record of plateau collision using the sedimentary strata deposited on the Siletzia oceanic plateau, which accreted to the Pacific Northwest at ca. 50 Ma. By combining previously published provenance and stratigraphic data with new lithofacies and geologic mapping, measured stratigraphic sections, conglomerate clast counts, and U-Pb zircon geochronology, we were able to divide the strata of the northern Olympic Peninsula in Washington, USA, into precollisional, syn-collisional, and postcollisional stages. Precollisional strata include early Eocene deep-marine hemipelagic to pelagic mudstones of the Aldwell Formation that were deposited directly on Siletzia basalts. These strata were deformed during collision and are separated from the overlying syn-collisional middle Eocene sandstone and conglomerate of the marine (?) Lyre Formation by an angular unconformity. Postcollisional strata were deposited by submarine fans and include interbedded sandstone and siltstone of the Hoko River and Makah formations. These units initially record the filling of isolated trench-slope basins by late Eocene time before eventual integration into an Oligocene regional forearc basin as the accreted Siletzia plateau began to subside. Our chronostratigraphy permits the correlation of basin strata across tectonic domains and provides more general insight into how forearc sedimentary systems evolve following the accretion of a young, buoyant oceanic plateau.
Clinical utility of novel diabetes subgroups in predicting vascular complications and mortality: up to 25 years of follow-up of the HUNT Study
Authors: Bjarkø Vera Vik , Haug Eirin Beate , Langhammer Arnulf , Ruiz Paz Lopez-Doriga , Carlsson Sofia , Birkeland Kare I , Berg Tore Julsrud , Sørgjerd Elin Pettersen , Lyssenko Valeriya , Åsvold Bjørn Olav
Published: November 2024

Introduction

Cluster analysis has previously revealed five reproducible subgroups of diabetes, differing in risks of diabetic complications. We aimed to examine the clusters’ predictive ability for vascular complications as compared with established risk factors in a general adult diabetes population.

Research design and methods

Participants from the second (HUNT2, 1995–1997) and third (HUNT3, 2006–2008) surveys of the Norwegian population-based Trøndelag Health Study (HUNT Study) with adult-onset diabetes were included (n=1899). To identify diabetes subgroups, we used the same variables (age at diagnosis, body mass index, HbA1c, homeostasis model assessment estimates of beta cell function and insulin resistance, and glutamic acid decarboxylase antibodies) and the same data-driven clustering technique as in previous studies. We used Cox proportional hazards models to investigate associations between clusters and risks of vascular complications and mortality. We estimated the C-index and R2to compare predictive abilities of the clusters to those of established risk factors as continuous variables. All models included adjustment for age, sex, diabetes duration and time of inclusion.

Results

We reproduced five subgroups with similar key characteristics as identified in previous studies. During median follow-up of 9–13 years (differing between outcomes), the clusters were associated with different risks of vascular complications and all-cause mortality. However, in prediction models, individual established risk factors were at least as good predictors as cluster assignment for all outcomes. For example, for retinopathy, the C-index for the model including clusters (0.65 (95% CI 0.63 to 0.68)) was similar to that of HbA1c (0.65 (95% CI 0.63 to 0.68)) or fasting C-peptide (0.66 (95% CI 0.63 to 0.68)) alone. For chronic kidney disease, the C-index for clusters (0.74 (95% CI 0.72 to 0.76)) was similar to that of triglyceride/high-density lipoprotein ratio (0.74 (95% CI 0.71 to 0.76)) or fasting C-peptide (0.74 (95% CI 0.72 to 0.76)), and baseline estimated glomerular filtration rate yielded a C-index of 0.76 (95% CI 0.74 to 0.78).

Conclusions

Cluster assignment did not provide better prediction of vascular complications or all-cause mortality compared with established risk factors.
Malnutrition and associated risk factors in orphanages in Punjab, Pakistan: an analytical study
Authors: Farid Muhammad Farhan , Rehman Alfur , Khaliq Ahmad Mujtaba , Ali Naveed , Tareq Ahmad Hussen
Published: November 2024

Background

Children living in orphanages face an increased susceptibility to malnutrition due to inadequate nutrition and psychological factors, in comparison to children who stay with their parents. A considerable proportion of institutionalised children remain unreported, and there is a dearth of information regarding the nutritional status of these children in Pakistan. This study set out to evaluate the status of malnutrition in the orphanages of Social Welfare Department Punjab.

Methodology

A multicentre analytical cross-sectional study was conducted from 12 December 2021 to 30 June 2022, with 255 study participants (aged 6–18 years) in seven orphanages (4 girls, 3 boys) out of 12 orphanages of government of Punjab. Anthropometric measurements were taken using standardised measuring instruments, and data were collected using structured questionnaire. Subjects were classed as malnourished based on body mass index for age and height for age reference growth charts of WHO 2007. Binary logistic regression was used to identify potential risk factors of malnutrition in orphanages.

Results

The study identified 36.1% malnourished children, of whom, 65.2% were orphans and 34% destitute children. The study reported 9.4% moderately underweight, 2.4% severely underweight, 4.3% overweight and 1.2% obese children and adolescents. The study established 17.6% moderately stunted, and 7.1% severely stunted children. Age at admission to orphanages (9–13 years) and lack of milk and meat consumption were identified as significant predictors of malnutrition in institutionalised children of Punjab.

Conclusion

Central Punjab had the highest malnutrition rate compared to North and South Punjab. Micronutrient deficiencies were more pronounced in South Punjab orphanages. Effective prevention of malnutrition requires early assessment of malnutritional risk in Pakistani orphanages.