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Microbiology Spectrum Jun 2024The aim of this study was to evaluate the proportion of resistance to a temocillin, tigecycline, ciprofloxacin, and chloramphenicol phenotype called t2c2 that resulted...
The aim of this study was to evaluate the proportion of resistance to a temocillin, tigecycline, ciprofloxacin, and chloramphenicol phenotype called t2c2 that resulted from mutations within the locus among extended-spectrum β-lactamases (ESBL-E) isolated in three intensive care units for 3 years in a French university hospital. Two parallel approaches were performed on all 443 ESBL-E included: (i) the minimal inhibitory concentrations of temocillin, tigecycline, ciprofloxacin, and chloramphenicol were determined and (ii) the genomes obtained from the Illumina sequencing platform were analyzed to determine multilocus sequence types, resistomes, and diversity of several -associated genes including operon. Among the 443 ESBL-E strains included, isolates of ( = 194), ( = 122), and complex () ( = 127) were found. Thirty-one ESBL-E strains (7%), 16 . (13.1%), and 15 (11.8%) presented the t2c2 phenotype in addition to their ESBL profile, whereas no presented these resistances. The t2c2 phenotype was invariably reversible by the addition of Phe-Arg-β-naphthylamide, indicating a role of resistance-nodulation-division pumps in these observations. Mutations associated with the t2c2 phenotype were restricted to RamR, the intergenic region (IR), and AcrR. Mutations in RamR consisted of C- or N-terminal deletions and amino acid substitutions inside its DNA-binding domain or within key sites of protein-substrate interactions. The IR showed nucleotide substitutions involved in the RamR DNA-binding domain. This diversity of sequences suggested that RamR and the IR represent major genetic events for bacterial antimicrobial resistance.IMPORTANCEMorbimortality caused by infectious diseases is very high among patients hospitalized in intensive care units (ICUs). A part of these outcomes can be explained by antibiotic resistance, which delays the appropriate therapy. The transferable antibiotic resistance gene is a well-known mechanism to explain the high rate of multidrug resistance (MDR) bacteria in ICUs. This study describes the prevalence of chromosomal mutations, which led to additional antibiotic resistance among MDR bacteria. More than 12% of and complex strains presented mutations within the locus associated with a dysregulation of an efflux pump called AcrAB-TolC and a porin: OmpF. These dysregulations led to an increase in antibiotic output notably tigecycline, ciprofloxacin, and chloramphenicol associated with a decrease of input for beta-lactam, especially temocillin. Mutations within transcriptional regulators such as locus played a major role in antibiotic resistance dissemination and need to be further explored.
PubMed: 38916360
DOI: 10.1128/spectrum.03548-23 -
Frontiers in Cellular and Infection... 2024Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant , particularly those that are carbapenem resistant. CZA resistance in producing PER, a class A...
INTRODUCTION
Ceftazidime/avibactam (CZA) is indicated against multidrug-resistant , particularly those that are carbapenem resistant. CZA resistance in producing PER, a class A extended-spectrum β-lactamase, has been well documented . However, data regarding clinical isolates are scarce. Our aim was to analyze the contribution of PER to CZA resistance in non-carbapenemase-producing clinical isolates that were ceftazidime and/or carbapenem non-susceptible.
METHODS
Antimicrobial susceptibility was determined through agar dilution and broth microdilution, while gene was screened through PCR. All PER-positive isolates and five PER-negative isolates were analyzed through Whole Genome Sequencing. The mutational resistome associated to CZA resistance was determined through sequence analysis of genes coding for PBPs 1b, 3 and 4, MexAB-OprM regulators MexZ, MexR, NalC and NalD, AmpC regulators AmpD and AmpR, and OprD porin. Loss of gene was induced in a PER-positive isolate by successive passages at 43°C without antibiotics.
RESULTS
Twenty-six of 287 isolates studied (9.1%) were CZA-resistant. Thirteen of 26 CZA-resistant isolates (50%) carried . One isolate carried but was CZA-susceptible. PER-producing isolates had significantly higher MICs for CZA, amikacin, gentamicin, ceftazidime, meropenem and ciprofloxacin than non-PER-producing isolates. All PER-producing isolates were ST309 and their gene was associated to ISCR1, an insertion sequence known to mobilize adjacent DNA. PER-negative isolates were classified as ST41, ST235 (two isolates), ST395 and ST253. PER-negative isolates carried genes for narrow-spectrum β-lactamases and the mutational resistome showed that all isolates had one major alteration in at least one of the genes analyzed. Loss of gene restored susceptibility to CZA, ceftolozane/tazobactam and other β-lactamsin the evolved isolate.
DISCUSSION
PER-3-producing ST309 is a successful multidrug-resistant clone with gene implicated in resistance to CZA and other β-lactams.
Topics: Ceftazidime; Pseudomonas aeruginosa; Azabicyclo Compounds; Microbial Sensitivity Tests; Humans; Drug Combinations; beta-Lactamases; Anti-Bacterial Agents; Pseudomonas Infections; Bacterial Proteins; Drug Resistance, Multiple, Bacterial; Chile; Whole Genome Sequencing; Mutation
PubMed: 38903939
DOI: 10.3389/fcimb.2024.1410834 -
Chemical Science Jun 2024Bacterial membrane porins facilitate the translocation of small molecules while restricting large molecules, and this mechanism remains elusive at the molecular level....
Bacterial membrane porins facilitate the translocation of small molecules while restricting large molecules, and this mechanism remains elusive at the molecular level. Here, we investigate the selective uptake of large cyclic sugars across an unusual passive membrane transporter, CymA, comprising a charged zone and a constricting N terminus segment. Using a combination of electrical recordings, protein mutagenesis and molecular dynamics simulations, we establish substrate translocation across CymA governed by the electrostatic pore properties and conformational dynamics of the constriction segment. Notably, we show that the variation in pH of the environment resulted in reversible modulation of the substrate binding site in the pore, thereby regulating charge-selective transport of cationic, anionic and neutral cyclic sugars. The quantitative kinetics of cyclic sugar translocation across CymA obtained in electrical recordings at different pHs are comparable with molecular dynamics simulations that revealed the transport pathway, energetics and favorable affinity sites in the pore for substrate binding. We further define the molecular basis of cyclic sugar translocation and establish that the constriction segment is flexible and can reside inside or outside the pore, regulating substrate translocation distinct from the ligand-gated transport mechanism. Our study provides novel insights into energy-independent large molecular membrane transport for targeted drug design strategies.
PubMed: 38903220
DOI: 10.1039/d4sc00345d -
BioRxiv : the Preprint Server For... May 2024Treatment of pulmonary disease requires multiple antibiotics including intravenous β-lactams (e.g., imipenem, meropenem). produces a β-lactamase (Bla ) that...
Treatment of pulmonary disease requires multiple antibiotics including intravenous β-lactams (e.g., imipenem, meropenem). produces a β-lactamase (Bla ) that inactivates β-lactam drugs but less efficiently carbapenems. Due to intrinsic and acquired resistance in and poor clinical outcomes, it is critical to understand the development of antibiotic resistance both within the host and in the setting of outbreaks. We compared serial longitudinally collected subsp. isolates from the index case of a CF center outbreak and four outbreak-related strains. We found strikingly high imipenem resistance in the later patient isolates, including the outbreak strain (MIC >512 µg/ml). The phenomenon was recapitulated upon exposure of intracellular bacteria to imipenem. Addition of the β-lactamase inhibitor avibactam abrogated the resistant phenotype. Imipenem resistance was caused by an increase in β-lactamase activity and increased mRNA level. Concurrent increase in transcription of preceding gene indicated upregulation of the entire operon in the resistant strains. Deletion of the porin coincided with the first increase in MIC (from 8 to 32 µg/ml). A frameshift mutation in responsible for the rough colony morphology, and a SNP in ATP-dependent helicase co-occurred with the second increase in MIC (from 32 to 256 µg/ml). Increased Bla expression and enzymatic activity may have been due to altered regulation of the - operon by the mutated HrpA alone, or in combination with other genes described above. This work supports using carbapenem/β-lactamase inhibitor combinations for treating , particularly imipenem resistant strains.
PubMed: 38903073
DOI: 10.1101/2024.05.08.593223 -
Nature Communications Jun 2024Extracellular ATP (eATP) signaling through the P2X7 receptor pathway is widely believed to trigger NLRP3 inflammasome assembly in microglia, potentially contributing to...
Extracellular ATP (eATP) signaling through the P2X7 receptor pathway is widely believed to trigger NLRP3 inflammasome assembly in microglia, potentially contributing to depression. However, the cellular stress responses of microglia to both eATP and stress itself remain largely unexplored. Mitochondria-associated membranes (MAMs) is a platform facilitating calcium transport between the endoplasmic reticulum (ER) and mitochondria, regulating ER stress responses and mitochondrial homeostasis. This study aims to investigate how MAMs influence microglial reaction and their involvement in the development of depression-like symptoms in response to chronic social defeat stress (CSDS). CSDS induced ER stress, MAMs' modifications, mitochondrial damage, and the formation of the IP3R3-GRP75-VDAC1 complex at the ER-mitochondria interface in hippocampal microglia, all concomitant with depression-like behaviors. Additionally, exposing microglia to eATP to mimic CSDS conditions resulted in analogous outcomes. Furthermore, knocking down GRP75 in BV2 cells impeded ER-mitochondria contact, calcium transfer, ER stress, mitochondrial damage, mitochondrial superoxide production, and NLRP3 inflammasome aggregation induced by eATP. In addition, reduced GRP75 expression in microglia of Cx3cr1Hspa9 mice lead to reduce depressive behaviors, decreased NLRP3 inflammasome aggregation, and fewer ER-mitochondria contacts in hippocampal microglia during CSDS. Here, we show the role of MAMs, particularly the formation of a tripartite complex involving IP3R3, GRP75, and VDAC1 within MAMs, in facilitating communication between the ER and mitochondria in microglia, thereby contributing to the development of depression-like phenotypes in male mice.
Topics: Animals; Mitochondria; Depression; Microglia; Mice; Social Defeat; Male; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Stress, Psychological; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Voltage-Dependent Anion Channel 1; Hippocampus; Adenosine Triphosphate; Inflammasomes; Inositol 1,4,5-Trisphosphate Receptors; Calcium; Membrane Proteins; Behavior, Animal; Mitochondria Associated Membranes; HSP70 Heat-Shock Proteins
PubMed: 38890305
DOI: 10.1038/s41467-024-49597-z -
Frontiers in Immunology 2024Aquaporin-4 antibodies (AQP4-Abs) are a diagnostic marker for patients with a demyelinating disease called neuromyelitis optica spectrum disorder (NMOSD). Anti-Argonaute...
Aquaporin-4 antibodies (AQP4-Abs) are a diagnostic marker for patients with a demyelinating disease called neuromyelitis optica spectrum disorder (NMOSD). Anti-Argonaute antibodies (AGO-Abs) present as potential biomarkers of the overlap syndrome between NMOSD and other autoimmune diseases. In this paper, we present the case of an adult woman with numbness, tingling, and burning sensations in her arms and subsequent bilateral internuclear ophthalmoplegia. Brain-cervical-thoracic magnetic resonance imaging (MRI) showed T2 hyperintensities in the dorsal brainstem and around the midbrain aqueduct and longitudinally transverse myelitis with homogeneous enhancement on gadolinium-enhanced MRI. The contemporaneous detection of AQP4- and AGO-Abs led to a definite diagnosis of overlap syndrome of NMOSD with AGO-Abs. The patient was treated with immunosuppressive agents, including corticosteroids and immunoglobulins, and achieved remission. This case highlights a novel phenotype of NMOSD with AGO-Abs overlap syndrome, which presents with relapsing brainstem syndrome and longitudinally extensive myelitis with acute severe neurological involvement. The promising prognosis of the disease could serve as a distinct clinical profile. Broad screening for antibodies against central nervous system autoimmune antigens is recommended in suspected patients with limited or atypical clinical manifestations.
Topics: Humans; Neuromyelitis Optica; Female; Autoantibodies; Aquaporin 4; Adult; Biomarkers; Magnetic Resonance Imaging; Middle Aged; Immunosuppressive Agents
PubMed: 38887290
DOI: 10.3389/fimmu.2024.1366531 -
CNS Neuroscience & Therapeutics Jun 2024The glymphatic system is cerebrospinal fluid-brain tissue fluid exchange flow mediated by aquaporin-4 (AQP4) on the end feet of astrocytes for a system, which is capable... (Review)
Review
The glymphatic system is cerebrospinal fluid-brain tissue fluid exchange flow mediated by aquaporin-4 (AQP4) on the end feet of astrocytes for a system, which is capable of rapidly removing brain metabolites and thus maintaining brain homeostasis, and is known as the central immune system. Dysfunction of the glymphatic system causes accumulation of misfolded and highly phosphorylated proteins (amyloid-β and Tau proteins), which destabilizes the proteins, and the body's neuroinflammatory factors are altered causing aging of the immune system and leading to neurodegenerative diseases. Damage to the glymphatic system and aging share common manifestations, as well as unstudied biological mechanisms that are also linked, such as mitochondria, oxidative stress, chronic inflammation, and sleep. In this paper, we first summarize the structure, function, and research methods of the glymphatic system and the relationship between the glymphatic system and the peripheral immune system, and second, sort out and summarize the factors of the glymphatic system in removing metabolites and resolving aging-related diseases and factors affecting aging, to explore its related biological mechanisms, and moreover, to provide a new way of thinking for treating or intervening aging-related diseases.
Topics: Humans; Glymphatic System; Aging; Animals; Astrocytes; Brain; Aquaporin 4
PubMed: 38887168
DOI: 10.1111/cns.14803 -
Neurology(R) Neuroimmunology &... Jul 2024AQP4 antibody-positive NMOSD (AQP4-NMOSD), MOG antibody-associated disease (MOGAD), and seronegative NMOSD (SN-NMOSD) are neuroautoimmune conditions that have...
BACKGROUND AND OBJECTIVES
AQP4 antibody-positive NMOSD (AQP4-NMOSD), MOG antibody-associated disease (MOGAD), and seronegative NMOSD (SN-NMOSD) are neuroautoimmune conditions that have overlapping clinical manifestations. Yet, important differences exist in these diseases, particularly in B-cell depletion (BCD) efficacy. Yet, the biology driving these differences remains unclear. Our study aims to clarify biological pathways distinguishing these diseases beyond autoantibodies and investigate variable BCD effects through proteomic comparisons.
METHODS
In a retrospective study, 1,463 serum proteins were measured in 53 AQP4-NMOSD, 25 MOGAD, 18 SN-NMOSD, and 49 healthy individuals. To identify disease subtype-associated signatures, we examined serum proteins in patients without anti-CD20 B-cell depletion (NoBCD). We then assessed the effect of BCD treatment within each subtype by comparing proteins between BCD-treated and NoBCD-treated patients.
RESULTS
In NoBCD-treated patients, serum profiles distinguished the 3 diseases. AQP4-NMOSD showed elevated type I interferon-induced chemokines (CXCL9 and CXCL10) and TFH chemokine (CXCL13). MOGAD exhibited increased cytotoxic T-cell proteases (granzyme B and granzyme H), while SN-NMOSD displayed elevated Wnt inhibitory factor 1, a marker for nerve injury. Across all subtypes, BCD-treated patients showed reduction of B-cell-associated proteins. In AQP4-NMOSD, BCD led to a decrease in several inflammatory pathways, including IL-17 signaling, cytokine storm, and macrophage activation. By contrast, BCD elevated these pathways in patients with MOGAD. BCD had no effect on these pathways in SN-NMOSD.
DISCUSSION
Proteomic profiles show unique biological pathways that distinguish AQP4-NMOSD, MOGAD, or SN-NMOSD. Furthermore, BCD uniquely affects inflammatory pathways in each disease type, providing an explanation for the disparate therapeutic response in AQP4-NMOSD and MOGAD.
Topics: Humans; Neuromyelitis Optica; Myelin-Oligodendrocyte Glycoprotein; Female; Middle Aged; Male; Adult; Retrospective Studies; Proteomics; B-Lymphocytes; Aquaporin 4; Autoantibodies; Aged
PubMed: 38885457
DOI: 10.1212/NXI.0000000000200268 -
Cancer Medicine Jun 2024Ovarian cancer is a common gynecological tumor with high malignant potential and poor prognosis. TRIM8, is involved in the development of various tumors, but its precise...
BACKGROUND
Ovarian cancer is a common gynecological tumor with high malignant potential and poor prognosis. TRIM8, is involved in the development of various tumors, but its precise regulatory role in ovarian cancer is still unknown.
AIMS
The aim of this study was to explore the specific mechanism by which TRIM8 regulates ovarian cancer.
MATERIALS AND METHODS
We used bioinformatics analysis to screen for high expression of TRIM8 in ovarian cancer. The expression of TRIM8 in healthy and cancerous ovarian tissues was assessed by immunofluorescence. TRIM8 was silenced or overexpressed in ovarian cancer cell lines, with cell proliferation and migration evaluated by CCK8, transwell and clonal formation assays. The effect of TRIM8 on ovarian cancer cells in vivo was assessed by subcutaneous tumor formation experiments in nude mice. The potential interacting protein VDAC2 was identified by mass spectrometry. The mechanism underlying TRIM8 regulation of VDAC2 was evaluated by co-immunoprecipitation and western blotting.
RESULTS
TRIM8 was overexpressed in ovarian cancer. TRIM8 promoted the proliferation and migration of ovarian cancer cells in vitro and the growth of subcutaneous tumors in mice in vivo. TRIM8 interacted with VDAC2, weakened the stability of the protein, and promoted its polyubiquitination and subsequent degradation. Knockdown of VDAC2 increased the resistance of ovarian cancer cells to iron death, whereas overexpression of VDAC2 attenuated ovarian cancer progression induced by TRIM8 overexpression.
DISCUSSION
TRIM8 promotes ovarian cancer proliferation and migration by targeting VDAC2 for ubiquitination and degradation, these finding may provide new targets for the treatment of ovarian cancer.
CONCLUSION
TRIM8 degraded VDAC2 through the ubiquitination pathway, increased the resistance of ovarian cancer cells to iron death, and promoted the proliferation and migration of ovarian cancer.
Topics: Humans; Female; Ovarian Neoplasms; Cell Proliferation; Ubiquitination; Cell Movement; Animals; Mice; Voltage-Dependent Anion Channel 2; Cell Line, Tumor; Mice, Nude; Proteolysis; Gene Expression Regulation, Neoplastic; Xenograft Model Antitumor Assays
PubMed: 38881325
DOI: 10.1002/cam4.7396 -
Beijing Da Xue Xue Bao. Yi Xue Ban =... Jun 2024To unveil the pathological changes associated with demyelination in schizophrenia (SZ) and its consequential impact on interstitial fluid (ISF) drainage, and to...
OBJECTIVE
To unveil the pathological changes associated with demyelination in schizophrenia (SZ) and its consequential impact on interstitial fluid (ISF) drainage, and to investigate the therapeutic efficacy of ursolic acid (UA) in treating demyelination and the ensuing abnormalities in ISF drainage in SZ.
METHODS
Female C57BL/6J mice, aged 6-8 weeks and weighing (20±2) g, were randomly divided into three groups: control, SZ model, and UA treatment. The control group received intraperitoneal injection (ip) of physiological saline and intragastric administration (ig) of 1% carboxymethylcellulose sodium (CMC-Na). The SZ model group was subjected to ip injection of 2 mg/kg dizocilpine maleate (MK-801) and ig administration of 1% CMC-Na. The UA treatment group underwent ig administration of 25 mg/kg UA and ip injection of 2 mg/kg MK-801. The treatment group received UA pretreatment via ig administration for one week, followed by a two-week drug intervention for all the three groups. Behavioral assessments, including the open field test and prepulse inhibition experiment, were conducted post-modeling. Subsequently, changes in the ISF partition drainage were investigated through fluorescent tracer injection into specific brain regions. Immunofluorescence analysis was employed to examine alterations in aquaporin 4 (AQP4) polarity distribution in the brain and changes in protein expression. Myelin reflex imaging using Laser Scanning Confocal Microscopy (LSCM) was utilized to study modifications in myelin within the mouse brain. Quantitative data underwent one-way ANOVA, followed by TukeyHSD for post hoc pairwise comparisons between the groups.
RESULTS
The open field test revealed a significantly longer total distance [(7 949.39±1 140.55) cm . (2 831.01±1 212.72) cm, < 0.001] and increased central area duration [(88.43±22.06) s . (56.85±18.58) s, =0.011] for the SZ model group compared with the controls. The UA treatment group exhibited signifi-cantly reduced total distance [(2 415.80±646.95) cm . (7 949.39±1 140.55) cm, < 0.001] and increased central area duration [(54.78±11.66) s . (88.43±22.06) s, =0.007] compared with the model group. Prepulse inhibition test results demonstrated a markedly lower inhibition rate of the startle reflex in the model group relative to the controls ( < 0.001 for both), with the treatment group displaying significant improvement ( < 0.001 for both). Myelin sheath analysis indicated significant demyelination in the model group, while UA treatment reversed this effect. Fluorescence tracing exhibited a significantly larger tracer diffusion area towards the rostral cortex and reflux area towards the caudal thalamus in the model group relative to the controls [(13.93±3.35) mm . (2.79±0.94) mm, < 0.001 for diffusion area; (2.48±0.38) mm . (0.05±0.12) mm, < 0.001 for reflux area], with significant impairment of drainage in brain regions. The treatment group demonstrated significantly reduced tracer diffusion and reflux areas [(7.93±2.48) mm . (13.93±3.35) mm, < 0.001 for diffusion area; (0.50±0.30) mm . (2.48±0.38) mm, < 0.001 for reflux area]. Immunofluorescence staining revealed disrupted AQP4 polarity distribution and reduced AQP4 protein expression in the model group compared with the controls [(3 663.88±733.77) μm . (13 354.92±4 054.05) μm, < 0.001]. The treatment group exhibited restored AQP4 polarity distribution and elevated AQP4 protein expression [(11 104.68±3 200.04) μm . (3 663.88±733.77) μm, < 0.001].
CONCLUSION
UA intervention ameliorates behavioral performance in SZ mice, Thus alleviating hyperactivity and anxiety symptoms and restoring sensorimotor gating function. The underlying mechanism may involve the improvement of demyelination and ISF drainage dysregulation in SZ mice.
Topics: Animals; Mice; Triterpenes; Schizophrenia; Mice, Inbred C57BL; Female; Disease Models, Animal; Demyelinating Diseases; Extracellular Fluid; Ursolic Acid; Dizocilpine Maleate; Aquaporin 4
PubMed: 38864135
DOI: 10.19723/j.issn.1671-167X.2024.03.016