Popeye-domain-containing proteins modulate the voltage-gated cardiac sodium channel Nav1. 5

iScience

Published On 2024/4/9

Popeye-domain-containing proteins (POPDC) are predominantly expressed in the heart and skeletal muscle, modulating the K2P potassium channel TREK-1 in a cAMP-dependent manner. POPDC1 and POPDC2 variants cause cardiac conduction disorders with or without muscular dystrophy. Searching for POPDC2-modulated ion channels using a functional co-expression screen in Xenopus oocytes, we found POPDC proteins to modulate the cardiac sodium channel Nav1.5. POPDC proteins downregulate Nav1.5 currents in a cAMP-dependent manner by reducing the surface expression of the channel. POPDC2 and Nav1.5 are both expressed in different regions of the murine heart and consistently POPDC2 co-immunoprecipitates with Nav1.5 from native cardiac tissue. Strikingly, the knock-down of popdc2 in embryonic zebrafish caused an increased upstroke velocity and overshoot of cardiac action potentials …

Journal

iScience

Published On

2024/4/9

Authors

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Position

Professor in Cardiovascular Sciences Institute of Cardiovascular Sciences

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55

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34

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0

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0

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0

Citation(since 2020)

0

Cited By

0

Research Interests

cardiology

arrhythmias

cardiomyopathy

translational research

inherited cardiac conditions

University Profile Page

Thomas Brand

Thomas Brand

Imperial College London

Position

Developmental Dynamics

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41

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21

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0

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0

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0

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0

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0

Research Interests

Heart Development

Sinus Node

cyclic AMP signalling

University Profile Page

Aytug K Kiper

Aytug K Kiper

Philipps-Universität Marburg

Position

Institute for Physiology and Pathophysiology AG Decher

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16

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15

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0

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0

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0

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0

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0

Research Interests

Electrophysiology

Ion channels

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Other Articles from authors

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Biomedicines

Endurance Training Provokes Arrhythmogenic Right Ventricular Cardiomyopathy Phenotype in Heterozygous Desmoglein-2 Mutants: Alleviation by Preload Reduction

Desmoglein-2 mutations are detected in 5–10% of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Endurance training accelerates the development of the ARVC phenotype, leading to earlier arrhythmic events. Homozygous Dsg2 mutant mice develop a severe ARVC-like phenotype. The phenotype of heterozygous mutant (Dsg2mt/wt) or haploinsufficient (Dsg20/wt) mice is still not well understood. To assess the effects of age and endurance swim training, we studied cardiac morphology and function in sedentary one-year-old Dsg2mt/wt and Dsg20/wt mice and in young Dsg2mt/wt mice exposed to endurance swim training. Cardiac structure was only occasionally affected in aged Dsg20/wt and Dsg2mt/wt mice manifesting as small fibrotic foci and displacement of Connexin 43. Endurance swim training increased the right ventricular (RV) diameter and decreased RV function in Dsg2mt/wt mice but not in wild types. Dsg2mt/wt hearts showed increased ventricular activation times and pacing-induced ventricular arrhythmia without obvious fibrosis or inflammation. Preload-reducing therapy during training prevented RV enlargement and alleviated the electrophysiological phenotype. Taken together, endurance swim training induced features of ARVC in young adult Dsg2mt/wt mice. Prolonged ventricular activation times in the hearts of trained Dsg2mt/wt mice are therefore a potential mechanism for increased arrhythmia risk. Preload-reducing therapy prevented training-induced ARVC phenotype pointing to beneficial treatment options in human patients.

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Frontiers in Cardiovascular Medicine

Overexpression of VEGFα as a biomarker of endothelial dysfunction in aortic tissue of α-GAL-Tg/KO mice and its upregulation in the serum of patients with Fabry’s disease

Introduction Fabry's disease is an X-linked lysosomal storage disorder caused by reduced activity of α-galactosidase A (GAL), leading to premature death on account of renal, cardiac, and vascular organ failure. Accumulation of the GAL substrate globotriaosylceramide (Gb3) in endothelial and smooth muscle cells is associated with early vascular cell damage, suggesting endothelial dysfunction as a driver of cardiorenal organ failure. Here, we studied the vascular expression of the key angiogenic factors, VEGFα and its antagonist angiostatin, in Fabry α-GAL-Tg/KO mice and determined circulating VEGFα and angiostatin serum levels in patients with Fabry’s disease and healthy controls. Methods Cryopreserved aortic vessels from six α-GAL-Tg/KO and six wild-type (WT) mice were obtained and VEGFα and angiostatin levels were determined by performing Western blot analysis. VEGFα expression was visualized by an immunohistochemical staining of paraffin aortic rings. In addition, VEGFα and angiostatin serum levels were measured by using an enzyme-linked immunosorbent assay in 48 patients with genetically verified Fabry's disease (50% male) and 22 healthy controls and correlated with disease severity markers such as lyso-Gb3, albuminuria, NTproBNP, high-sensitive troponin T (hsTNT), and myocardial wall thickness. Results It was found that there was a significant increase in VEGFα protein expression (1.66 ± 0.35 vs. 0.62 ± 0.16, p = 0.0009) and a decrease in angiostatin expression (0.024 ± 0.007 vs. 0.053 ± 0.02, p = 0.038) in aortic lysates from α-GAL-Tg/KO compared with that from WT mice. Immunohistochemical …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Cardiovascular Research

Blood-based cardiometabolic phenotypes in atrial fibrillation and their associated risk: EAST-AFNET 4 biomolecule study

Background Atrial fibrillation (AF) and concomitant cardiometabolic disease processes interact and combine to lead to adverse events such as stroke, heart failure, myocardial infarction, and cardiovascular death. Circulating biomolecules provide quantifiable proxies for cardiometabolic disease processes. Their role in defining subphenotypes of AF is not known. Methods and results This prespecified analysis of the EAST-AFNET4 biomolecule study assigned patients to clusters using polytomous variable latent class analysis (poLCA) based on baseline concentrations of thirteen precisely-quantified biomolecules potentially reflecting ageing, cardiac fibrosis, metabolic dysfunction, oxidative stress, cardiac load, endothelial dysfunction, and inflammation. In each cluster, rates of cardiovascular death, stroke, or hospitalization for heart failure or acute coronary syndrome, the primary …

Thomas Brand

Thomas Brand

Imperial College London

Genes

POPDC1 Variants Cause Atrioventricular Node Dysfunction and Arrhythmogenic Changes in Cardiac Electrophysiology and Intracellular Calcium Handling in …

Popeye domain-containing (POPDC) proteins selectively bind cAMP and mediate cellular responses to sympathetic nervous system (SNS) stimulation. The first discovered human genetic variant (POPDC1S201F) is associated with atrioventricular (AV) block, which is exacerbated by increased SNS activity. Zebrafish carrying the homologous mutation (popdc1S191F) display a similar phenotype to humans. To investigate the impact of POPDC1 dysfunction on cardiac electrophysiology and intracellular calcium handling, homozygous popdc1S191F and popdc1 knock-out (popdc1KO) zebrafish larvae and adult isolated popdc1S191F hearts were studied by functional fluorescent analysis. It was found that in popdc1S191F and popdc1KO larvae, heart rate (HR), AV delay, action potential (AP) and calcium transient (CaT) upstroke speed, and AP duration were less than in wild-type larvae, whereas CaT duration was greater. SNS stress by β-adrenergic receptor stimulation with isoproterenol increased HR, lengthened AV delay, slowed AP and CaT upstroke speed, and shortened AP and CaT duration, yet did not result in arrhythmias. In adult popdc1S191F zebrafish hearts, there was a higher incidence of AV block, slower AP upstroke speed, and longer AP duration compared to wild-type hearts, with no differences in CaT. SNS stress increased AV delay and led to further AV block in popdc1S191F hearts while decreasing AP and CaT duration. Overall, we have revealed that arrhythmogenic effects of POPDC1 dysfunction on cardiac electrophysiology and intracellular calcium handling in zebrafish are varied, but already present in early development …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Europace

Disturbed atrial metabolism, shear stress, and cardiac load contribute to atrial fibrillation after ablation: AXAFA biomolecule study

Aims Different disease processes can combine to cause atrial fibrillation (AF). Their contribution to recurrent AF after ablation in patients is not known. Cardiovascular processes associated with recurrent AF after AF ablation were determined by quantifying biomolecules related to inflammation, metabolism, proliferation, fibrosis, shear stress, atrial pressure, and others in the AXAFA biomolecule study. Methods and results Twelve circulating cardiovascular biomolecules (ANGPT2, BMP10, CA125, hsCRP, ESM1, FABP3, FGF23, GDF15, IGFBP7, IL6, NT-proBNP, and hsTnT) were quantified in plasma samples obtained prior to a first AF ablation using high-throughput, high-precision assays. Cox regression was used to identify biomolecules associated with recurrent AF during the first 3 months after AF ablation. In 433 patients (64 years [58, 70]; 33% women), baseline …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

ESC Heart Failure

Multimodal characterization of dilated cardiomyopathy: Geno‐And Phenotyping of PrImary Cardiomyopathy (GrAPHIC)

Aims Cardiomyopathies (CMPs) are a heterogeneous group of diseases that are defined by structural and functional abnormalities of the cardiac muscle. Dilated cardiomyopathy (DCM), the most common CMP, is defined by left ventricular dilation and impaired contractility and represents a common cause of heart failure. Different phenotypes result from various underlying genetic and acquired causes with variable effects on disease development and progression, prognosis, and response to medical treatment. Current treatment algorithms do not consider these different aetiologies, due to lack of insights into treatable drivers of cardiac failure in patients with DCM. Our study aims to precisely phenotype and genotype the various subtypes of DCM and hereby lay the foundation for individualized therapy. Methods and results The Geno‐ And Phenotyping of PrImary Cardiomyopathy (GrAPHIC) is a currently ongoing …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Europace

Longer and better lives for patients with atrial fibrillation: the 9th AFNET/EHRA consensus conference

Aims Recent trial data demonstrate beneficial effects of active rhythm management in patients with atrial fibrillation (AF) and support the concept that a low arrhythmia burden is associated with a low risk of AF-related complications. The aim of this document is to summarize the key outcomes of the 9th AFNET/EHRA Consensus Conference of the Atrial Fibrillation NETwork (AFNET) and the European Heart Rhythm Association (EHRA). Methods and results Eighty-three international experts met in Münster for 2 days in September 2023. Key findings are as follows: (i) Active rhythm management should be part of the default initial treatment for all suitable patients with AF. (ii) Patients with device-detected AF have a low burden of AF and a low risk of stroke. Anticoagulation prevents some strokes and also increases major but non-lethal bleeding. (iii) More research is needed to …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Biomedicines

Structural Progression in Patients with Definite and Non-Definite Arrhythmogenic Right Ventricular Cardiomyopathy and Risk of Major Adverse Cardiac Events

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare inherited disease characterised by early arrhythmias and structural changes. Still, there are limited echocardiography data on its structural progression. We studied structural progression and its impact on the occurrence of major adverse cardiovascular events (MACE). In this single-centre observational cohort study, structural progression was defined as the development of new major or minor imaging 2010 Task Force Criteria during follow-up. Of 101 patients, a definite diagnosis of ARVC was made in 51 patients, while non-definite ‘early’ disease was diagnosed in 50 patients. During 4 years of follow-up (IQR: 2–6), 23 (45%) patients with a definite diagnosis developed structural progression while only 1 patient in the non-definite (early) group gained minor imaging Task Force Criteria. Male gender was strongly associated with structural progression (62% of males progressed structurally, while 88% of females remained stable). Patients with structural progression were at higher risk of MACE (64% of patients with MACE had structural progression). Therefore, the rate of structural progression is an essential factor to be considered in ARVC studies.

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Atrial fibrillation in the young: consider heritable conditions like short QT syndrome

When atrial fibrillation (AF) is diagnosed as the cause of palpitations or fainting in a young person, it is so 1 unusual that we may find an inherited cardiac condition if we look for it, and even a rare one. While long 2 QT syndrome is well known in the cardiovascular community, short QT syndrome (SQTS) was only 3 described at the beginning of the millennium and is rare. This heritable cardiac condition can lead to atrial 4 fibrillation at an early age and can be complicated by ventricular arrhythmias and sudden death. It is 5 currently defined by a short QT interval in the ECG of< 320 ms alone or< 360 ms in combination with a 6 family history of SQTS, aborted cardiac arrest in the absence of heart disease or another pathogenic 7 variant1. SQTS was primarily associated with gain of function pathological variants in the repolarizing 8 potassium channel genes (KCNH2, KCNQ1, KCNJ21, 2) and more recently with loss of …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Scientific Data

Publisher Correction: High resolution optical mapping of cardiac electrophysiology in pre-clinical models

Publisher Correction: High resolution optical mapping of cardiac electrophysiology in pre-clinical models - PMC Back to Top Skip to main content NIH NLM Logo Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation Search PMC Full-Text Archive Search in PMC Advanced Search User Guide Journal List Sci Data v.11; 2024 PMC10796748 Other Formats PDF (618K) Actions Cite Collections Share Permalink Copy RESOURCES Similar articles Cited by other articles Links to NCBI Databases Journal List Sci Data v.11; 2024 PMC10796748 As a library, NLM provides access to scientific literature. Inclusion in an NLM database does not imply endorsement of, or agreement with, the contents by NLM or the National Institutes of Health. Learn more: PMC Disclaimer | PMC Copyright Notice Logo of sdata Sci Data. 2024; 11: 93. Published online 2024 Jan 18. doi: 10.1038/s41597-024-02941-w …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

The Journal of Physiology

Reduced plakoglobin increases the risk of sodium current defects and atrial conduction abnormalities in response to androgenic anabolic steroid abuse

Abstract Androgenic anabolic steroids (AAS) are commonly abused by young men. Male sex and increased AAS levels are associated with earlier and more severe manifestation of common cardiac conditions, such as atrial fibrillation, and rare ones, such as arrhythmogenic right ventricular cardiomyopathy (ARVC). Clinical observations suggest a potential atrial involvement in ARVC. Arrhythmogenic right ventricular cardiomyopathy is caused by desmosomal gene defects, including reduced plakoglobin expression. Here, we analysed clinical records from 146 ARVC patients to identify that ARVC is more common in males than females. Patients with ARVC also had an increased incidence of atrial arrhythmias and P wave changes. To study desmosomal vulnerability and the effects of AAS on the atria, young adult male mice, heterozygously deficient for plakoglobin (Plako+/−), and wild type (WT) littermates were …

Thomas Brand

Thomas Brand

Imperial College London

Plant Disease

Multi-Year Field Plantings Evaluating Boxwood Cultivars for Susceptibility to the Blight Pathogens (Calonectria spp.) in Northern Germany

Two multiyear field trials were conducted to evaluate boxwood cultivars for their susceptibility to the blight pathogens Calonectria pseudonaviculata and C. henricotiae in northern Germany. Fifteen cultivars were included in the first trial from 2007 to 2012, and 46 cultivars were included in the second trial from 2014 to 2017. Both trials were done in a naturally infested field that was supplemented with infected plant tissue added to the soil before planting. Each cultivar had three replicate hedge sections with 10 plants per section, and they were assessed annually for blight severity expressed as proportion of leaves blighted and fallen. Blight severity varied significantly among years (P < 0.0001) and cultivars (P < 0.05) within each trial. In the first trial, mean severity ranged from 0.03 to 0.11 for the most resistant cultivars and 0.35 to 0.96 for the most susceptible ones. Similarly, in the second trial, mean severity ranged …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Europace

Familial atrial fibrillation mutation M1875T-SCN5A increases early sodium current and dampens the effect of flecainide

Aims Atrial fibrillation (AF) is the most common cardiac arrhythmia. Pathogenic variants in genes encoding ion channels are associated with familial AF. The point mutation M1875T in the SCN5A gene, which encodes the α-subunit of the cardiac sodium channel Nav1.5, has been associated with increased atrial excitability and familial AF in patients. Methods and results We designed a new murine model carrying the Scn5a-M1875T mutation enabling us to study the effects of the Nav1.5 mutation in detail in vivo and in vitro using patch clamp and microelectrode recording of atrial cardiomyocytes, optical mapping, electrocardiogram, echocardiography, gravimetry, histology, and biochemistry. Atrial cardiomyocytes from newly generated adult Scn5a-M1875T+/− mice showed a selective increase in the early (peak) cardiac sodium current, larger action potential amplitude, and a …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

Europace

Heart Failure, Female Sex, and Atrial Fibrillation Are the Main Drivers of Human Atrial Cardiomyopathy: Results From the CATCH ME Consortium

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): CATCH ME: Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly Background Atrial cardiomyopathy is emerging as independent prognostic factor in cardiovascular disease. Fibrotic remodeling, cardiomyocyte hypertrophy and a reduction in capillary density are histological hallmarks of atrial cardiomyopathy. The contribution of etiological factors to atrial cardiomyopathy has not been robustly quantified. Purpose To quantify the relation between histological features of atrial cardiomyopathy and the clinical profile of patients. Methods We examined left (LA, n=91) and right (RA, n=75) atrial appendages sampled from a European cohort of patients undergoing cardiac surgery. Quantification of …

Larissa Fabritz, CL Fabritz, FL Fabritz

Larissa Fabritz, CL Fabritz, FL Fabritz

University of Birmingham

173 Progression of arrhythmogenic right ventricular cardiomyopathy (arvc) and risk of major adverse cardiac events

Background In patients with Arrhythmogenic right ventricular cardiomyopathy (ARVC, also called "Arrhythmogenic Cardiomyopathy"), it is a challenge to predict those at greatest risk of major adverse cardiac events (MACE). Our hypothesis is that risk of arrhythmia may be preceded by change in ventricular structure and function.Purpose To assess the association between change in ventricular structure and function over time and risk of (MACE) in ARVC.Methods 101 definite and non-definite ARVC patients (defined as per Revised task force criteria (TFC)) were included with at least two sequential echocardiography and ECGs between 2010 and 2022. Structural progression was defined as development of new 2010 TFC on echocardiography during follow-up. MACE were defined as ventricular fibrillation (VF), sustained ventricular tachycardia (Sus VT), appropriate implantable cardio-defibrillator (ICD) therapy …

Aytug K Kiper

Aytug K Kiper

Philipps-Universität Marburg

Communications Biology

Cloxyquin activates hTRESK by allosteric modulation of the selectivity filter

The TWIK-related spinal cord K+ channel (TRESK, K2P18.1) is a K2P channel contributing to the maintenance of membrane potentials in various cells. Recently, physiological TRESK function was identified as a key player in T-cell differentiation rendering the channel a new pharmacological target for treatment of autoimmune diseases. The channel activator cloxyquin represents a promising lead compound for the development of a new class of immunomodulators. Identification of cloxyquin binding site and characterization of the molecular activation mechanism can foster the future drug development. Here, we identify the cloxyquin binding site at the M2/M4 interface by mutational scan and analyze the molecular mechanism of action by protein modeling as well as in silico and in vitro electrophysiology using different permeating ion species (K+ / Rb+). In combination with kinetic analyses of channel inactivation, our …

Thomas Brand

Thomas Brand

Imperial College London

Gesunde Pflanzen

First Report on Colletotrichum sansevieriae Causing Anthracnose of Sansevieria trifasciata in Germany

Sansevieria species are valued in Europe as potted houseplants because of their modest maintenance requirements and low susceptibility to diseases and pests. Water-soaked leaf spots that eventually coalesced into large, drying lesions were observed on Sansevieria trifasciata freshly imported from Costa Rica. A Colletotrichum was isolated from the fungal fruiting bodies that developed on these necroses. It was confidently determined to be C. sansevieriae based on the host plant and microbiological as well as molecular biology test results. This is the first detection of C. sansevieriae in Germany.

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Iscience

TOP1 and R-loops facilitate transcriptional DSBs at hypertranscribed cancer driver genes

DNA double-stranded breaks (DSBs) pose a significant threat to genomic integrity, and their generation during essential cellular processes like transcription remains poorly understood. In this study, we employ several techniques to map DSBs, R-loops, and topoisomerase 1 cleavage complex (TOP1cc) to comprehensively investigate the interplay between transcription, DSBs, topoisomerase 1 (TOP1), and R-loops. Our findings reveal the presence of DSBs at highly expressed genes enriched with TOP1 and R-loops. Remarkably, transcription-associated DSBs at these loci are significantly reduced upon depletion of R-loops and TOP1, uncovering the pivotal roles of TOP1 and R-loops in transcriptional DSB formation. By elucidating the intricate interplay between TOP1cc trapping, R-loops, and DSBs, our study provides insights into the mechanisms underlying transcription-associated genomic instability. Moreover …

Nicholas M. Blauch

Nicholas M. Blauch

Carnegie Mellon University

Iscience

Visual word processing engages a hierarchical, distributed, and bilateral cortical network

Although the Visual Word Form Area (VWFA) in left temporal cortex is considered the pre-eminent region in visual word processing, other regions are also implicated. We examined the entire text-selective circuit, using functional MRI. Ten regions of interest (ROIs) per hemisphere were defined, which, based on clustering, grouped into early vision, high-level vision, and language clusters. We analyzed the responses of the ROIs and clusters to words, inverted words, and consonant strings using univariate, multivariate, and functional connectivity measures. Bilateral modulation by stimulus condition was evident, with a stronger effect in left hemisphere regions. Last, using graph theory, we observed that the VWFA was equivalently connected with early visual and language clusters in both hemispheres, reflecting its role as a mediator in the circuit. Although the individual ROIs and clusters bilaterally were flexibly altered …

Carmen G Feijoo

Carmen G Feijoo

Universidad Andrés Bello

Iscience

Definitive hematopoiesis is dispensable to sustain erythrocytes and macrophages during zebrafish ontogeny

In all organisms studied, from flies to humans, blood cells emerge in several sequential waves and from distinct hematopoietic origins. However, the relative contribution of these ontogenetically distinct hematopoietic waves to embryonic blood lineages and to tissue regeneration during development is yet elusive. Here, using a lineage-specific "switch and trace" strategy in the zebrafish embryo, we report that the definitive hematopoietic progeny barely contributes to erythrocytes and macrophages during early development. Lineage tracing further shows that ontogenetically distinct macrophages exhibit differential recruitment to the site of injury based on the developmental stage of the organism. We further demonstrate that primitive macrophages can solely maintain tissue regeneration during early larval developmental stages after selective ablation of definitive macrophages. Our findings highlight that the …

Graeme C. Hays

Graeme C. Hays

Deakin University

iScience

A pulse check for trends in sea turtle numbers across the globe

Population declines of vertebrates are common, but rebuilding marine life may be possible. We assessed trends in sea turtle numbers globally, building 61 time series of abundance extending beyond 2015, representing monitoring in >1200 years. Increases were widespread with significant upward trends, no significant change, and significant downward trends in 28, 28, and 5 time series, respectively. For example, annual nest numbers increased between 1980 and 2018 from around 4,000 to 16,000 for green turtles at Aldabra (Seychelles, Indian Ocean) and between 2008 and 2020 from around 500 to 35,000 for loggerhead turtles in Sal (Cape Verde, north Atlantic). However, conservation concerns remain. Major populations may experience declines, such as loggerhead turtles in Oman, while previous upward trends can be reversed, as with green turtles nesting at Tortuguero (Costa Rica, Caribbean). Further …

Hailiang Mei

Hailiang Mei

Universiteit Leiden

Iscience

Oleic acid triggers metabolic rewiring of T cells poising them for T helper 9 differentiation

T cells are the most common immune cells in atherosclerotic plaques, and the function of T cells can be altered by fatty acids. Here, we show that pre-exposure of CD4+ T cells to oleic acid, an abundant fatty acid linked to cardiovascular events, upregulates core metabolic pathways and promotes differentiation into interleukin-9 (IL-9)-producing cells upon activation. RNA sequencing of non-activated T cells reveals that oleic acid upregulates genes encoding key enzymes responsible for cholesterol and fatty acid biosynthesis. Transcription footprint analysis links these expression changes to the differentiation toward TH9 cells, a pro-atherogenic subset. Spectral flow cytometry shows that pre-exposure to oleic acid results in a skew toward IL-9+-producing T cells upon activation. Importantly, pharmacological inhibition of either cholesterol or fatty acid biosynthesis abolishes this effect, suggesting a beneficial role for …

Kah Chun Lau

Kah Chun Lau

California State University, Northridge

Iscience

First-principles study of MXene properties with varying hydrofluoric acid concentration

With varying hydrofluoric acid (HF) concentrations under three etching conditions, we presented a comparative study of the effects of both the ordered and randomly ternary mixed terminated Ti3C2Tx surfaces with a wide variation of O/OH/F stoichiometry on the thermodynamic stability and electronic properties. Regardless of the HF concentration, an OH-rich surface is found to be thermodynamically stable and the electrical conductivity of Ti3C2Tx is substantially affected by the OH concentration. The charge density difference and electron localization function demonstrated a significant electron localization at the hydroxyl group on the O/OH/F mixed terminated surface, which could yield a locally induced dipole on the surface that renders favorable reaction sites on the functionalized surface. In addition, a large tunability in the work function (ΔΦ ∼ 3.5 eV) is predicted for Ti3C2Tx. These findings provide a pathway for …

Parinita Agrawal

Parinita Agrawal

National Institute of Technology, Rourkela

iScience

Kuragel: A biomimetic hydrogel scaffold designed to promote corneal regeneration

Cornea-related injuries are the most common cause of blindness worldwide. Transplantation remains the primary approach for addressing corneal blindness, though the demand for donor corneas outmatches the supply by millions. Tissue adhesives employed to seal corneal wounds have shown inefficient healing and incomplete vision restoration. We have developed a biodegradable hydrogel – Kuragel, with the ability to promote corneal regeneration. Functionalized gelatin and hyaluronic acid form photo-crosslinkable hydrogel with transparency and compressive modulus similar to healthy human cornea. Kuragel composition was tuned to achieve sufficient adhesive strength for sutureless integration to host tissue, with minimal swelling post-administration. Studies in the New Zealand rabbit mechanical injury model affecting corneal epithelium and stroma demonstrate that Kuragel efficiently promotes re …

Olof Eriksson

Olof Eriksson

Uppsala Universitet

Iscience

Non-invasive PET imaging of liver fibrogenesis using a RESCA-conjugated Affibody molecule

Non-invasive assessment of fibrogenic activity, rather than fibrotic scars, could significantly improve the management of fibrotic diseases and the development of anti-fibrotic drugs. This study explores the potential of an Affibody molecule (Z09591) labeled with the Al(18)F-RESCA method as a tracer for the non-invasive detection of fibrogenic cells. Z09591 was functionalized with the restrained complexing agent (RESCA) chelator for direct labeling with [18F]Al-F. In vivo PET/MRI scans on U-87 tumor-bearing mice exhibited high selectivity of the resulting radiotracer, [18F]AlF-RESCA-Z09591, for PDGFRβ, with minimal non-specific background uptake. Evaluation in a mouse model with carbon tetrachloride-induced fibrotic liver followed by a disease regression phase, revealed the radiotracer's high affinity and specificity for fibrogenic cells in fibrotic livers (standardized uptake value (SUV) 0.43±0.05), with uptake …

Lee Wetzler

Lee Wetzler

Boston University

Iscience

Characterizing adjuvants’ effects at murine immunoglobulin repertoire level

Generating large-scale, high-fidelity sequencing data is challenging and, furthermore, not much has been done to characterize adjuvants' effects at the repertoire level. Thus, we introduced an IgSeq pipeline that standardized library prep protocols and data analysis functions for accurate repertoire profiling. We then studied systemically effects of CpG and Alum on the Ig heavy chain repertoire using the ovalbumin (OVA) murine model. Ig repertoires of different tissues (spleen and bone marrow) and isotypes (IgG and IgM) were examined and compared in IGHV mutation, gene usage, CDR3 length, clonal diversity, and clonal selection. We found Ig repertoires of different compartments exhibited distinguishable profiles at the non-immunized steady state, and distinctions became more pronounced upon adjuvanted immunizations. Notably, Alum and CpG effects exhibited different tissue- and isotype-preferences. The …