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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 -
MBio Jul 2024Nasopharyngeal carriage of staphylococci spreads potentially pathogenic strains into (peri)oral regions and increases the chance of cross-infections. Some laboratory...
UNLABELLED
Nasopharyngeal carriage of staphylococci spreads potentially pathogenic strains into (peri)oral regions and increases the chance of cross-infections. Some laboratory strains can also move rapidly on hydrated agar surfaces, but the biological relevance of these observations is not clear. Using soft-agar [0.3% (wt/vol)] plate assays, we demonstrate the rapid surface dispersal of (peri)oral isolates of and and closely related laboratory strains in the presence of mucin glycoproteins. Mucin-induced dispersal was a stepwise process initiated by the passive spreading of the growing colonies followed by their rapid branching (dendrites) from the colony edge. Although most spreading strains used mucin as a growth substrate, dispersal was primarily dependent on the lubricating and hydrating properties of the mucins. Using JE2 as a genetically tractable representative, we demonstrate that mucin-induced dendritic dispersal, but not colony spreading, is facilitated by the secretion of surfactant-active phenol-soluble modulins (PSMs) in a process regulated by the quorum-sensing system. Furthermore, the dendritic dispersal of JE2 colonies was further stimulated in the presence of surfactant-active supernatants recovered from the most robust (peri)oral spreaders of and . These findings suggest complementary roles for lubricating mucins and staphylococcal PSMs in the active dispersal of potentially pathogenic strains from perioral to respiratory mucosae, where gel-forming, hydrating mucins abound. They also highlight the impact that interspecies interactions have on the co-dispersal of with other perioral bacteria, heightening the risk of polymicrobial infections and the severity of the clinical outcomes.
IMPORTANCE
Despite lacking classical motility machinery, nasopharyngeal staphylococci spread rapidly in (peri)oral and respiratory mucosa and cause cross-infections. We describe laboratory conditions for the reproducible study of staphylococcal dispersal on mucosa-like surfaces and the identification of two dispersal stages (colony spreading and dendritic expansion) stimulated by mucin glycoproteins. The mucin type mattered as dispersal required the surfactant activity and hydration provided by some mucin glycoproteins. While colony spreading was a passive mode of dispersal lubricated by the mucins, the more rapid and invasive form of dendritic expansion of and required additional lubrication by surfactant-active peptides (phenol-soluble modulins) secreted at high cell densities through quorum sensing. These results highlight a hitherto unknown role for gel-forming mucins in the dispersal of staphylococcal strains associated with cross-infections and point at perioral regions as overlooked sources of carriage and infection by staphylococci.
PubMed: 38953351
DOI: 10.1128/mbio.01562-24 -
Zhongguo Yi Xue Ke Xue Yuan Xue Bao.... Jun 2024Alzheimer's disease (AD) is a severe threat to human health and one of the three major causes of human death.Double-stranded RNA-dependent protein kinase (PKR) is an... (Review)
Review
Alzheimer's disease (AD) is a severe threat to human health and one of the three major causes of human death.Double-stranded RNA-dependent protein kinase (PKR) is an interferon-induced protein kinase involved in innate immunity.In the occurrence and development of AD,PKR is upregulated and continuously activated.On the one hand,the activation of PKR triggers an integrated stress response in brain cells.On the other hand,it indirectly upregulates the expression of β-site amyloid precursor protein cleaving enzyme 1 and facilitates the accumulation of amyloid-β protein (Aβ),which could activate PKR activator to further activate PKR,thus forming a sustained accumulation cycle of Aβ.In addition,PKR can promote Tau phosphorylation,thereby reducing microtubule stability in nerve cells.Inflammation in brain tissue,neurotoxicity resulted from Aβ accumulation,and disruption of microtubule stability led to the progression of AD and the declines of memory and cognitive function.Therefore,PKR is a key molecule in the development and progression of AD.Effective PKR detection can aid in the diagnosis and prediction of AD progression and provide opportunities for clinical treatment.The inhibitors targeting PKR are expected to control the activity of PKR,thereby controlling the progression of AD.Therefore,PKR could be a target for the development of therapeutic drugs for AD.
Topics: Alzheimer Disease; Humans; eIF-2 Kinase; Amyloid beta-Peptides; tau Proteins; Phosphorylation; Brain; Amyloid beta-Protein Precursor
PubMed: 38953267
DOI: 10.3881/j.issn.1000-503X.15792 -
Zhongguo Yi Xue Ke Xue Yuan Xue Bao.... Jun 2024Objective To explore the relationship between the expression levels of microRNA-155 (miR-155) and suppressor of cytokine signaling 1 (SOCS1) in the colonic mucosal...
[Correlations Between the Expression of MicroRNA-155 and Suppressor of Cytokine Signaling 1 in Colonic Mucosal Tissue and Disease Severity in Patients With Ulcerative Colitis].
Objective To explore the relationship between the expression levels of microRNA-155 (miR-155) and suppressor of cytokine signaling 1 (SOCS1) in the colonic mucosal tissue of patients with ulcerative colitis (UC) and the severity of the disease.Methods A total of 130 UC patients admitted to the Second Affiliated Hospital of Hebei North University from September 2021 to June 2023 were selected.According to the modified Mayo score system,the patients were assigned into an active stage group (=85) and a remission stage group (=45).According to the modified Truelove and Witts classification criteria,the UC patients at the active stage were assigned into a mild group (=35),a moderate group (=30),and a severe group (=20).A total of 90 healthy individuals who underwent colonoscopy for physical examination or those who had normal colonoscopy results after single polypectomy and excluded other diseases were selected as the control group.The colonic mucosal tissues of UC patients with obvious lesions and the colonic mucosal tissue 20 cm away from the anus of the control group were collected.The levels of miR-155 and SOCS1 mRNA in tissues were determined by fluorescence quantitative PCR,and the expression of SOCS1 protein in tissues was determined by immunohistochemistry.The correlations of the levels of miR-155 and SOCS1 mRNA in the colonic mucosal tissue with the modified Mayo score of UC patients were analyzed.The values of the levels of miR-155 and SOCS1 mRNA in predicting the occurrence of severe illness in the UC patients at the active stage were evaluated.Results Compared with the control group and the remission stage group,the active stage group showed up-regulated expression level of miR-155,down-regulated level of SOCS1 mRNA,and decreased positive rate of SOCS1 protein in the colonic mucosal tissue (all <0.001).The expression level of miR-155 and modified Mayo score in colonic mucosal tissues of UC patients at the active stage increased,while the mRNA level of SOCS1 was down-regulated as the disease evolved from being mild to severe (all <0.001).The modified Mayo score was positively correlated with the miR-155 level and negative correlated with the mRNA level of SOCS1 in colonic mucosal tissues of UC patients (all <0.001).The high miR-155 level (=2.762,95%=1.284-5.944,=0.009),low mRNA level of SOCS1 (=2.617,95%=1.302-5.258,=0.007),and modified Mayo score≥12 points (=3.232,95%=1.450-7.204,=0.004) were all risk factors for severe disease in the UC patients at the active stage.The area under curve of miR-155 combined with SOCS1 mRNA in predicting severe illness in the UC patients at the active stage was 0.920.Conclusions The expression levels of miR-155 and SOCS1 mRNA were correlated with the disease severity in the UC patients at the active stage.The combination of the two indicators demonstrates good performance in predicting the occurrence of severe illness in UC patients at the active stage.
Topics: Humans; MicroRNAs; Colitis, Ulcerative; Suppressor of Cytokine Signaling 1 Protein; Intestinal Mucosa; Severity of Illness Index; Colon; Female; Male; Middle Aged; Adult
PubMed: 38953257
DOI: 10.3881/j.issn.1000-503X.15863 -
Indian Journal of Ophthalmology Jul 2024
Topics: Humans; Angiogenesis Inhibitors; Vascular Endothelial Growth Factor A; Visual Acuity; Intravitreal Injections; Diabetic Retinopathy; Macular Edema; Bevacizumab; Ranibizumab; Treatment Outcome; Tomography, Optical Coherence
PubMed: 38953138
DOI: 10.4103/IJO.IJO_40_24 -
Indian Journal of Ophthalmology Jul 2024
Topics: Humans; Intravitreal Injections; Administration, Oral; Central Serous Chorioretinopathy; Rifampin; Vascular Endothelial Growth Factor A; Propranolol; Angiogenesis Inhibitors; Adrenergic beta-Antagonists
PubMed: 38953136
DOI: 10.4103/IJO.IJO_3022_23 -
Infection and Drug Resistance 2024The emergence of multidrug-resistant () and the decline of effective antibiotics lead to the urgent need for new antibacterial agents. The aim of this study is to...
INTRODUCTION
The emergence of multidrug-resistant () and the decline of effective antibiotics lead to the urgent need for new antibacterial agents. The aim of this study is to investigate the therapeutic effect of antimicrobial peptides against gentamicin-resistant (RT) and to screen effective antimicrobial peptides.
METHODS
In this study, the RT strains were induced by gradient gentamicin, and the RT strains were selected by detecting the expression levels of efflux pump genes, porin genes, and biofilm formation genes of the strains combined with their effects on the cells. Then the effects of four antimicrobial peptides on the efflux pump activity, biofilm formation level and cell condition after infection were detected to explore the effects of antimicrobial peptides on RT strains. Finally, the RT strain was used to induce a mouse model of pneumonia, and the four antimicrobial peptides were used to treat pneumonia mice for in vivo experiments. The pathological changes in lung tissues in each group were detected to explore the antimicrobial peptide with the most significant effect on the RT strain in vivo.
RESULTS
The results showed that the minimal inhibitory concentrations of the RT strains (strain C and strain I) were significantly higher than those of the wild-type strain, and the expression of efflux pump, porin and biofilm formation genes was significantly increased. The antimicrobial peptides could effectively inhibit the biofilm formation and efflux pump protein function of the RT strains. In addition, the antimicrobial peptides showed promising antibacterial effects both in vitro and .
DISCUSSION
Our study provided a theoretical basis for the treatment of gentamicin resistant infection with antimicrobial peptides, and found that KLA was significantly superior to LL37, Magainin I, KLA and Dermaseptin (10 μg/mL in cells, 50 μg in mice).
PubMed: 38953095
DOI: 10.2147/IDR.S462653 -
Frontiers in Immunology 2024Hereditary angioedema (HAE) is a rare disease characterized by localized and self-limited angioedema (AE) attacks. A local increase of bradykinin (BK) mediates AE...
BACKGROUND
Hereditary angioedema (HAE) is a rare disease characterized by localized and self-limited angioedema (AE) attacks. A local increase of bradykinin (BK) mediates AE attacks in HAE, however the role of inflammation in HAE has been poorly explored We aim to analyze the role of inflammatory mediators in HAE patients during AE attacks.
METHODS
Patients with a confirmed HAE diagnosis due to C1 inhibitor deficiency (HAE-C1INH) or patients gene mutations (HAE-FXII) attending to our outpatient clinic between November-2019 and May-2022 were included. Demographic and clinical characteristics were analyzed. Blood samples were collected both during symptom-free periods (baseline) and during HAE attacks, and acute phase reactants (APR), such as serum amyloid A (SAA), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-Dimer and white blood cells were measured.
RESULTS
Seventy-eight patients were enrolled in the study, with a predominant representation of women (76%, n=59), and a mean age of 47.8 years (range 6-88). Among them, 67% (n=52) of patients had HAE-C1INH (46 classified as type 1 and 6 as type 2) while 33% (n=26) had HAE-FXII. During attack-free periods, the majority of patients exhibited normal levels of SAA, ESR, D-dimer, ACE and WCC. However, in a subset of patients (16% for SAA, 18% for ESR, and 14.5% for D-dimer), elevations were noted at baseline. Importantly, during HAE attacks, significant increases were observed in SAA in 88% of patients (p< 0.0001 vs. baseline), in ESR in 65% (p= 0.003 baseline) and D-dimer in 71% (p=0.001 . baseline) of the patients. A comparison between baseline and acute attack levels in 17 patients revealed significant differences in SAA AA (p<0. 0001), ESR (p<0.0001) and D-dimer (p= 0.004). No significant differences were observed in CRP (p=0.7), ACE (p=0.67) and WCC (p=0.54). These findings remained consistent regardless of HAE type, disease activity or location of angioedema.
CONCLUSION
The systemic increase in APR observed during HAE attacks suggests that inflammation extends beyond the localized edematous area. This finding underscores the potential involvement of inflammatory pathways in HAE and highlights the need for further investigation into their role in the pathophysiology of HAE.
Topics: Humans; Female; Male; Adult; Angioedemas, Hereditary; Middle Aged; Biomarkers; Aged; Inflammation; Adolescent; Child; Young Adult; Aged, 80 and over; Complement C1 Inhibitor Protein; Serum Amyloid A Protein; Factor XII; Blood Sedimentation; Inflammation Mediators; Fibrin Fibrinogen Degradation Products
PubMed: 38953032
DOI: 10.3389/fimmu.2024.1400526 -
Frontiers in Immunology 2024Equine asthma (EA) is a common lower airway disease in horses, but whether its pathogenesis is allergic is ambiguous. Extrinsic stimuli like hay dust induce acute...
INTRODUCTION
Equine asthma (EA) is a common lower airway disease in horses, but whether its pathogenesis is allergic is ambiguous. Extrinsic stimuli like hay dust induce acute exacerbation of clinical signs and sustained local neutrophilic inflammation in susceptible horses. is an EA stimulus, but it is unclear if it merely acts as an IgE-provoking allergen. We aimed to comprehensively analyze immunoglobulin (Ig) isotypes in EA, elucidating their binding to different antigens, and their quantities systemically in serum and locally in bronchoalveolar lavage fluid (BALF).
METHODS
Serum and BALF from healthy horses (HE, = 18) and horses with mild-moderate asthma (MEA, = 20) or severe asthma (SEA, = 24) were compared. Ig isotype (IgG1, IgG3/5, IgG4/7, IgG6, IgA, and IgE) binding to nine antigens ( lysate, and recombinant Asp f 1, Asp f 7, Asp f 8, dipeptidyl-peptidase 5, class II aldolase/adducin domain protein, glucoamylase, beta-hexosaminidase, and peptide hydrolase) was compared by enzyme-linked immunosorbent assays. Total Ig isotype contents were determined by bead-based assays.
RESULTS
MEA and SEA differed from HE but hardly from each other. Compared to HE, asthmatic horses showed increased anti- binding of IgG (BALF and serum) and IgA (BALF). Serum and BALF IgE binding and total IgE contents were similar between HE and EA. Single antigens, as well as lysate, yielded similar Ig binding patterns. Serum and BALF IgG1 binding to all antigens was increased in SEA and to several antigens in MEA. Serum IgG4/7 binding to two antigens was increased in SEA. BALF IgA binding to all antigens was increased in SEA and MEA. Total BALF IgG1 and IgG4/7 contents were increased in SEA, and serum IgG4/7 content was increased in MEA compared to HE. Yet, total isotype contents differentiated EA and HE less clearly than antigen-binding Ig.
DISCUSSION
immunogenicity was confirmed without identification of single dominant antigens here. provoked elevated BALF IgG1 and IgA binding, and these isotypes appear relevant for neutrophilic EA, which does not support allergy. BALF Ig isotype differentiation beyond IgE is crucial for a comprehensive analysis of immune responses to fungi in EA pathogenesis.
Topics: Animals; Horses; Aspergillus fumigatus; Bronchoalveolar Lavage Fluid; Asthma; Immunoglobulin G; Immunoglobulin A; Horse Diseases; Antigens, Fungal; Male; Neutrophils; Female; Immunoglobulin E; Antibodies, Fungal
PubMed: 38953030
DOI: 10.3389/fimmu.2024.1406794 -
Frontiers in Immunology 2024Human Herpesvirus 6B (HHV-6B) impedes host immune responses by downregulating class I MHC molecules (MHC-I), hindering antigen presentation to CD8+ T cells....
INTRODUCTION
Human Herpesvirus 6B (HHV-6B) impedes host immune responses by downregulating class I MHC molecules (MHC-I), hindering antigen presentation to CD8+ T cells. Downregulation of MHC-I disengages inhibitory receptors on natural killer (NK) cells, resulting in activation and killing of the target cell if NK cell activating receptors such as NKG2D have engaged stress ligands upregulated on the target cells. Previous work has shown that HHV-6B downregulates three MHC-like stress ligands MICB, ULBP1, and ULBP3, which are recognized by NKG2D. The U20 glycoprotein of the related virus HHV-6A has been implicated in the downregulation of ULBP1, but the precise mechanism remains undetermined.
METHODS
We set out to investigate the role of HHV-6B U20 in modulating NK cell activity. We used HHV-6B U20 expressed as a recombinant protein or transduced into target cells, as well as HHV-6B infection, to investigate binding interactions with NK cell ligands and receptors and to assess effects on NK cell activation. Small-angle X-ray scattering was used to align molecular models derived from machine-learning approaches.
RESULTS
We demonstrate that U20 binds directly to ULBP1 with sub-micromolar affinity. Transduction of U20 decreases NKG2D binding to ULBP1 at the cell surface but does not decrease ULBP1 protein levels, either at the cell surface or in toto. HHV-6B infection and soluble U20 have the same effect. Transduction of U20 blocks NK cell activation in response to cell-surface ULBP1. Structural modeling of the U20 - ULBP1 complex indicates some similarities to the m152-RAE1γ complex.
Topics: Humans; Killer Cells, Natural; Herpesvirus 6, Human; GPI-Linked Proteins; NK Cell Lectin-Like Receptor Subfamily K; Lymphocyte Activation; Protein Binding; Viral Proteins; Glycoproteins; Intracellular Signaling Peptides and Proteins
PubMed: 38953028
DOI: 10.3389/fimmu.2024.1363156