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MBio Jul 2024causes millions of mucosal infections in humans annually. Hyphal overgrowth on mucosal surfaces is frequently associated with tissue damage caused by candidalysin, a...
UNLABELLED
causes millions of mucosal infections in humans annually. Hyphal overgrowth on mucosal surfaces is frequently associated with tissue damage caused by candidalysin, a secreted peptide toxin that destabilizes the plasma membrane of host cells thereby promoting disease and immunopathology. Candidalysin was first identified in strain SC5314, but recent investigations have revealed candidalysin "variants" of differing amino acid sequence in isolates of , and the related species , and , suggesting that sequence variation among candidalysins may be widespread in natural populations of these species. Here, we analyzed gene sequences from 182 . isolates, 10 . isolates, and 78 . isolates and identified 10, 3, and 2 candidalysin variants in these species, respectively. Application of candidalysin variants to epithelial cells revealed differences in the ability to cause cellular damage, changes in metabolic activity, calcium influx, MAPK signalling, and cytokine secretion, while biophysical analyses indicated that variants exhibited differences in their ability to interact with and permeabilize a membrane. This study identifies candidalysin variants with differences in biological activity that are present in medically relevant species.
IMPORTANCE
Fungal infections are a significant burden to health. Candidalysin is a toxin produced by that damages host tissues, facilitating infection. Previously, we demonstrated that candidalysins exist in the related species and , thereby identifying these molecules as a toxin family. Recent genomic analyses have highlighted the presence of a small number of candidalysin "variant" toxins, which have different amino acid sequences to those originally identified. Here, we screened genome sequences of isolates of , , and and identified candidalysin variants in all three species. When applied to epithelial cells, candidalysin variants differed in their ability to cause damage, activate intracellular signaling pathways, and induce innate immune responses, while biophysical analysis revealed differences in the ability of candidalysin variants to interact with lipid bilayers. These findings suggest that intraspecies variation in candidalysin amino acid sequence may influence fungal pathogenicity.
PubMed: 38953356
DOI: 10.1128/mbio.03351-23 -
Endocrinology Jul 2024Neprilysin is a ubiquitous peptidase that can modulate glucose homeostasis by cleaving insulinotropic peptides. While global deletion of neprilysin protects mice against...
Neprilysin is a ubiquitous peptidase that can modulate glucose homeostasis by cleaving insulinotropic peptides. While global deletion of neprilysin protects mice against high fat diet (HFD)-induced insulin secretory dysfunction, strategies to ablate neprilysin in a tissue-specific manner are favored to limit off-target effects. Since insulinotropic peptides are produced in the gut, we sought to determine whether gut-specific neprilysin deletion confers beneficial effects on insulin secretion similar to that of global neprilysin deletion in mice fed HFD. Mice with conditional deletion of neprilysin in enterocytes (NEPGut-/-) were generated by crossing Vil-Cre and floxed neprilysin (NEPfl/fl) mice. Neprilysin activity was almost abolished throughout the gut in NEPGut-/- mice, and was similar in plasma, pancreas and kidney in NEPGut-/- vs control mice. An oral glucose tolerance test was performed at baseline and following 14 weeks of HFD feeding, during which glucose tolerance and glucose-stimulated insulin secretion (GSIS) were assessed. Despite similar body weight gain at 14 weeks, NEPGut-/- displayed lower fasting plasma glucose levels, improved glucose tolerance and increased GSIS compared to control mice. In conclusion, gut-specific neprilysin deletion recapitulates the enhanced GSIS seen with global neprilysin deletion in high-fat-fed mice. Thus, strategies to inhibit neprilysin specifically in the gut may protect against fat-induced glucose intolerance and beta-cell dysfunction.
PubMed: 38953181
DOI: 10.1210/endocr/bqae080 -
Transplantation Direct Jul 2024A prior single-center, retrospective cohort study identified baseline lung allograft dysfunction (BLAD) as a risk factor for death in bilateral lung transplant...
BACKGROUND
A prior single-center, retrospective cohort study identified baseline lung allograft dysfunction (BLAD) as a risk factor for death in bilateral lung transplant recipients. In this multicenter prospective cohort study, we test the association of BLAD with death in bilateral lung transplant recipients, identify clinical risk factors for BLAD, and assess its association with allograft injury on the molecular level.
METHODS
This multicenter, prospective cohort study included 173 bilateral lung transplant recipients that underwent serial pulmonary function testing and plasma collection for donor-derived cell-free DNA at prespecified time points. BLAD was defined as failure to achieve ≥80% predicted for both forced expiratory volume in 1 s and forced vital capacity after lung transplant, on 2 consecutive measurements at least 3 mo apart.
RESULTS
BLAD was associated with increased risk of death (hazard ratio, 1.97; 95% confidence interval [CI], 1.05-3.69; = 0.03) but not chronic lung allograft dysfunction alone (hazard ratio, 1.60; 95% CI, 0.87-2.95; = 0.13). Recipient obesity (odds ratio, 1.69; 95% CI, 1.15-2.80; = 0.04) and donor age (odds ratio, 1.03; 95% CI, 1.02-1.05; = 0.004) increased the risk of developing BLAD. Patients with BLAD did not demonstrate higher log(donor-derived cell-free DNA) levels compared with no BLAD (slope [SE]: -0.0095 [0.0007] versus -0.0109 [0.0007]; = 0.15).
CONCLUSIONS
BLAD is associated with an increased risk of death following lung transplantation, representing an important posttransplant outcome with valuable prognostic significance; however, early allograft specific injury on the molecular level does not increase the risk of BLAD, supporting further mechanistic insight into disease pathophysiology.
PubMed: 38953039
DOI: 10.1097/TXD.0000000000001669 -
Frontiers in Veterinary Science 2024Post-ovulatory aging is a time-dependent deterioration of ovulated oocytes and a major limiting factor reducing the fitness of offspring. This process may lead to the...
INTRODUCTION
Post-ovulatory aging is a time-dependent deterioration of ovulated oocytes and a major limiting factor reducing the fitness of offspring. This process may lead to the activation of cell death pathways like apoptosis in oocytes.
METHODOLOGY
We evaluated oocyte membrane integrity, egg developmental competency, and mRNA abundance of apoptosis-related genes by RT-qPCR. Oocytes from zebrafish were retained at 28.5°C for 24 h post-ovulation (HPO). Viability was assessed using trypan blue (TB) staining. The consequences of in vivo oocyte aging on the developmental competence of progeny were determined by the embryo survival at 24 h post fertilization, hatching, and larval malformation rates.
RESULTS
The fertilization, oocyte viability, and hatching rates were 91, 97, and 65% at 0 HPO and dropped to 62, 90, and 22% at 4 HPO, respectively. The fertilizing ability was reduced to 2% at 8 HPO, while 72% of oocytes had still intact plasma membranes. Among the apoptotic genes (b-cell lymphoma 2), (bcl2-associated agonist of cell death a), (tumor protein p53), (cyclin-dependent kinase 1) studied, mRNA abundance of anti-apoptotic decreased and pro-apoptotic increased at 24 HPO. Furthermore, and mRNA transcripts decreased at 24 HPO compared to 0 HPO.
DISCUSSION
Thus, TB staining did not detect the loss of oocyte competency if caused by aging. TB staining, however, could be used as a simple and rapid method to evaluate the quality of zebrafish oocytes before fertilization. Taken together, our results indicate the activation of cell death pathways in the advanced stages of oocyte aging in zebrafish.
PubMed: 38952806
DOI: 10.3389/fvets.2024.1389070 -
BioRxiv : the Preprint Server For... Jun 2024This study illustrates a vital role for ankyrin-B in lens architecture, growth and function through its involvement in membrane protein and spectrin-actin cytoskeletal...
This study illustrates a vital role for ankyrin-B in lens architecture, growth and function through its involvement in membrane protein and spectrin-actin cytoskeletal organization and stability The transparent ocular lens is essential for vision by focusing light onto the retina. Despite recognizing the importance of its unique cellular architecture and mechanical properties, the molecular mechanisms governing these attributes remain elusive. This study aims to elucidate the role of ankyrin-B (AnkB), a membrane scaffolding protein, in lens cytoarchitecture, growth and function using a conditional knockout (cKO) mouse model. AnkB cKO mouse has no defects in lens morphogenesis, but exhibited changes that supported a global role for AnkB in maintenance of lens clarity, size, cytoarchitecture, and stiffness. Notably, absence of AnkB led to nuclear cataract formation, evident from P16. AnkB cKO lens fibers exhibit progressive disruption in membrane organization of the spectrin-actin cytoskeleton, channel proteins, cell-cell adhesion, shape change, loss and degradation of several membrane proteins (e.g., NrCAM. N-cadherin and aquaporin-0) along with a disorganized plasma membrane and impaired ball-and-socket membrane interdigitations. Furthermore, absence of AnkB led to decreased lens stiffness. Collectively, these results illustrate the essential role for AnkB in lens architecture, growth and function through its involvement in membrane protein and cytoskeletal organization.
PubMed: 38952798
DOI: 10.1101/2024.06.12.598702 -
MedRxiv : the Preprint Server For... Jun 2024The immunometabolic mechanisms underlying variable responses to oral immunotherapy (OIT) in patients with IgE-mediated food allergy are unknown.
BACKGROUND
The immunometabolic mechanisms underlying variable responses to oral immunotherapy (OIT) in patients with IgE-mediated food allergy are unknown.
OBJECTIVE
To identify novel pathways associated with tolerance in food allergy, we used metabolomic profiling to find pathways important for food allergy in multi-ethnic cohorts and responses to OIT.
METHODS
Untargeted plasma metabolomics data were generated from the VDAART healthy infant cohort (N=384), a Costa Rican cohort of children with asthma (N=1040), and a peanut OIT trial (N=20) evaluating sustained unresponsiveness (SU, protection that lasts after therapy) versus transient desensitization (TD, protection that ends immediately afterwards). Generalized linear regression modeling and pathway enrichment analysis identified metabolites associated with food allergy and OIT outcomes.
RESULTS
Compared with unaffected children, those with food allergy were more likely to have metabolomic profiles with altered histidines and increased bile acids. Eicosanoids (e.g., arachidonic acid derivatives) (q=2.4×10 ) and linoleic acid derivatives (q=3.8×10 ) pathways decreased over time on OIT. Comparing SU versus TD revealed differing concentrations of bile acids (q=4.1×10 ), eicosanoids (q=7.9×10 ), and histidine pathways (q=0.015). In particular, the bile acid lithocholate (4.97[1.93,16.14], p=0.0027), the eicosanoid leukotriene B4 (3.21[1.38,8.38], p=0.01), and the histidine metabolite urocanic acid (22.13[3.98,194.67], p=0.0015) were higher in SU.
CONCLUSIONS
We observed distinct profiles of bile acids, histidines, and eicosanoids that vary among patients with food allergy, over time on OIT and between SU and TD. Participants with SU had higher levels of metabolites such as lithocholate and urocanic acid, which have immunomodulatory roles in key T-cell subsets, suggesting potential mechanisms of tolerance in immunotherapy.
KEY MESSAGES
- Compared with unaffected controls, children with food allergy demonstrated higher levels of bile acids and distinct histidine/urocanic acid profiles, suggesting a potential role of these metabolites in food allergy. - In participants receiving oral immunotherapy for food allergy, those who were able to maintain tolerance-even after stopping therapyhad lower overall levels of bile acid and histidine metabolites, with the exception of lithocholic acid and urocanic acid, two metabolites that have roles in T cell differentiation that may increase the likelihood of remission in immunotherapy.
CAPSULE SUMMARY
This is the first study of plasma metabolomic profiles of responses to OIT in individuals with IgE-mediated food allergy. Identification of immunomodulatory metabolites in allergic tolerance may help identify mechanisms of tolerance and guide future therapeutic development.
PubMed: 38952781
DOI: 10.1101/2024.05.31.24308233 -
Frontiers in Molecular Biosciences 2024The study of energy transduction in eukaryotic cells has been divided between Bioenergetics and Physiology, reflecting and contributing to a variety of Bioenergetic...
The study of energy transduction in eukaryotic cells has been divided between Bioenergetics and Physiology, reflecting and contributing to a variety of Bioenergetic myths considered here: 1) ATP production = energy production, 2) energy transduction is confined to mitochondria (plus glycolysis and chloroplasts), 3) mitochondria only produce heat when required, 4) glycolysis is inefficient compared to mitochondria, and 5) mitochondria are the main source of reactive oxygen species (ROS) in cells. These myths constitute a 'mitocentric' view of the cell that is wrong or unbalanced. In reality, mitochondria are the main site of energy dissipation and heat production in cells, and this is an essential function of mitochondria in mammals. Energy transduction and ROS production occur throughout the cell, particularly the cytosol and plasma membrane, and all cell membranes act as two-dimensional energy conduits. Glycolysis is efficient, and produces less heat per ATP than mitochondria, which might explain its increased use in muscle and cancer cells.
PubMed: 38952719
DOI: 10.3389/fmolb.2024.1402910 -
Cureus Jun 2024Multiple myeloma (MM) immunophenotyping (IPT) and measurable residual disease (MRD) monitoring by flow cytometry is a surrogate for progression-free survival and overall...
BACKGROUND
Multiple myeloma (MM) immunophenotyping (IPT) and measurable residual disease (MRD) monitoring by flow cytometry is a surrogate for progression-free survival and overall survival in clinical trials. However, plasma cell enumeration is challenging owing to morphological discrepancies and plasma cell (PC) loss during the sample processing.
METHODS
In (n=87) newly diagnosed MM patients, we evaluated the immunophenotype of PCs at baseline, and for a subset of 35 patients MRD at post-induction was quantified and analyzed for association with outcomes and survival. The software Statistical Package for Social Sciences (SPSS), version 16.0 (SPSS Inc., Chicago, IL, USA) was used for all the statistical analysis.
RESULTS
Immunophenotyping showed strong positive expression of CD56 (83%), CD200 (94%), CD38 (92%), and CD117 (91%) and negative/weak expression of CD19 (83%), CD45 (89%), CD27 (74%), and CD81 (90%) respectively. Negative/weak expression of CD19 was significantly associated with age ≥56 years (p<0.048), with lower albumin (<3.4g/dL, p<0.001). Strong positive CD56 expression was significantly associated with the presence of M-protein (p<0.03). Strong positive CD117 expression was significantly associated with lower albumin (p<0.02). Strong positive CD200 expression was significantly associated with a good response (p<0.02). The median (IQR) value of bone marrow (BM)-MRD% was 0.005 (0.002-0.034). We found that there was no significant difference in the correlation, association, and survival outcomes with MRD%.
CONCLUSION
This study sheds light on the utility of IPT as an invaluable diagnostic tool in disease management. The findings of this study could be important when it comes to modifying the criteria for high-risk diseases and implementing a risk-adapted first therapy in clinical practice.
PubMed: 38952609
DOI: 10.7759/cureus.61504 -
Clinical Transplantation Jul 2024We aimed to evaluate the characteristics, clinical outcomes, and blood product transfusion (BPT) rates of patients undergoing cardiac transplant (CT) while receiving... (Observational Study)
Observational Study
BACKGROUND
We aimed to evaluate the characteristics, clinical outcomes, and blood product transfusion (BPT) rates of patients undergoing cardiac transplant (CT) while receiving uninterrupted anticoagulation and antiplatelet therapy.
METHODS
A retrospective, single-center, and observational study of adult patients who underwent CT was performed. Patients were classified into four groups: (1) patients without anticoagulation or antiplatelet therapy (control), (2) patients on antiplatelet therapy (AP), (3) patients on vitamin K antagonists (AVKs), and (4) patients on dabigatran (dabigatran). The primary endpoints were reoperation due to bleeding and perioperative BPT rates (packed red blood cells (PRBC), fresh frozen plasma, platelets). Secondary outcomes assessed included morbidity and mortality-related events.
RESULTS
Of the 55 patients included, 6 (11%) received no therapy (control), 8 (15%) received antiplatelet therapy, 15 (27%) were on AVKs, and 26 (47%) were on dabigatran. There were no significant differences in the need for reoperation or other secondary morbidity-associated events. During surgery patients on dabigatran showed lower transfusion rates of PRBC (control 100%, AP 100%, AVKs 73%, dabigatran 50%, p = 0.011) and platelets (control 100%, AP 100%, AVKs 100%, dabigatran 69%, p = 0.019). The total intraoperative number of BPT was also the lowest in the dabigatran group (control 5.5 units, AP 5 units, AVKs 6 units, dabigatran 3 units; p = 0.038); receiving significantly less PRBC (control 2.5 units, AP 3 units, AVKs 2 units, dabigatran 0.5 units; p = 0.011). A Poisson multivariate analysis showed that only treatment on dabigatran reduces PRBC requirements during surgery, with an expected reduction of 64.5% (95% CI: 32.4%-81.4%).
CONCLUSIONS
In patients listed for CT requiring anticoagulation due to nonvalvular atrial fibrillation, the use of dabigatran and its reversal with idarucizumab significantly reduces intraoperative BPT demand.
Topics: Humans; Female; Male; Retrospective Studies; Middle Aged; Platelet Aggregation Inhibitors; Anticoagulants; Follow-Up Studies; Heart Transplantation; Prognosis; Blood Transfusion; Risk Factors; Aged; Adult; Dabigatran; Postoperative Complications
PubMed: 38952201
DOI: 10.1111/ctr.15380 -
Immunological Medicine Jul 2024Type I interferons (IFN-Is) play a significant role in systemic lupus erythematosus (SLE) pathogenesis. Double-filtration plasmapheresis (DFPP) is a treatment option for...
Type I interferons (IFN-Is) play a significant role in systemic lupus erythematosus (SLE) pathogenesis. Double-filtration plasmapheresis (DFPP) is a treatment option for SLE; however, its effect on IFN-Is remains unclear. Therefore, we investigated the effects of DFPP on IFN-Is. Plasma from patients with SLE ( = 11) who regularly underwent DFPP was analysed using a cell-based reporter system to detect the bioavailability and inducing activity of IFN-I. The concentration of plasma dsDNA was measured, and western blotting analysis was used to assess the phosphorylation of the STING pathway. A higher IFN-I bioavailability and inducing activity were observed in patients compared to healthy controls, and both parameters decreased after DFPP. The reduction in IFN-I-inducing activity was particularly prominent in patients with high disease activity. Notably, this reduction was not observed in STING-knockout reporter cells. Additionally, plasma dsDNA levels decreased after DFPP treatment, suggesting that inhibition of the STING pathway was responsible for the observed decrease in activity. Western blotting analysis revealed suppression of STING pathway phosphorylation after DFPP. DFPP reduced IFN-I bioavailability and the inducing activity of plasma. This reduction is likely attributable to the inhibition of the STING pathway through the elimination of dsDNA.
PubMed: 38952099
DOI: 10.1080/25785826.2024.2372918