Small-molecule caspase-1 inhibitor CZL80 terminates refractory status epilepticus via inhibition of glutamatergic transmission.

Status epilepticus (SE), a serious and often life-threatening medical emergency, is characterized by abnormally prolonged seizures. It is not effectively managed by present first-line anti-seizure medications and could readily develop into drug resistance without timely treatment. In this study, we highlight the therapeutic potential of CZL80, a small molecule that inhibits caspase-1, in SE termination and its related mechanisms. We found that delayed treatment of diazepam (0.5 h) easily induces resistance in kainic acid (KA)-induced SE. CZL80 dose-dependently terminated diazepam-resistant SE, extending the therapeutic time window to 3 h following SE, and also protected against neuronal damage. Interestingly, the effect of CZL80 on SE termination was model-dependent, as evidenced by ineffectiveness in the pilocarpine-induced SE. Further, we found that CZL80 did not terminate KA-induced SE in Caspase-1-/- mice but partially terminated SE in IL1R1-/- mice, suggesting the SE termination effect of CZL80 was dependent on the caspase-1, but not entirely through the downstream IL-1ß pathway. Furthermore, in vivo calcium fiber photometry revealed that CZL80 completely reversed the neuroinflammation-augmented glutamatergic transmission in SE. Together, our results demonstrate that caspase-1 inhibitor CZL80 terminates diazepam-resistant SE by blocking glutamatergic transmission. This may be of great therapeutic significance for the clinical treatment of refractory SE.

Chaperone-tip adhesin complex is vital for synergistic activation of CFA/I fimbriae biogenesis.

Colonization factor CFA/I defines the major adhesive fimbriae of enterotoxigenic Escherichia coli and mediates bacterial attachment to host intestinal epithelial cells. The CFA/I fimbria consists of a tip-localized minor adhesive subunit, CfaE, and thousands of copies of the major subunit CfaB polymerized into an ordered helical rod. Biosynthesis of CFA/I fimbriae requires the assistance of the periplasmic chaperone CfaA and outer membrane usher CfaC. Although the CfaE subunit is proposed to initiate the assembly of CFA/I fimbriae, how it performs this function remains elusive. Here, we report the establishment of an in vitro assay for CFA/I fimbria assembly and show that stabilized CfaA-CfaB and CfaA-CfaE binary complexes together with CfaC are sufficient to drive fimbria formation. The presence of both CfaA-CfaE and CfaC accelerates fimbria formation, while the absence of either component leads to linearized CfaB polymers in vitro. We further report the crystal structure of the stabilized CfaA-CfaE complex, revealing features unique for biogenesis of Class 5 fimbriae.

Structural and Functional Insights into PpgL, a Metal-Independent ß-Propeller Gluconolactonase That Contributes to Pseudomonas aeruginosa Virulence.

Biofilm formation is a critical determinant in the pathopoiesis of Pseudomonas aeruginosa It could significantly increase bacterial resistance to drugs and host defense. Thus, inhibition of biofilm matrix production could be regarded as a promising attempt to prevent colonization of P. aeruginosa and the subsequent infection. PpgL, a periplasmic gluconolactonase, has been reported to be involved in P. aeruginosa quorum-sensing (QS) system regulation. However, the detailed function and catalysis mechanism remain elusive. Here, the crystal structure of PpgL is described in the current study, along with biochemical analysis, revealing that PpgL is a typical ß-propeller enzyme with unique metal-independent lactone hydrolysis activity. Consequently, comparative analysis of seven-bladed propeller lactone-catalyzing enzymes and mutagenesis studies identify the critical sites which contribute to the diverse catalytic and substrate recognition functions. In addition, the reduced biofilm formation and attenuated invasion phenotype resulting from deletion of ppgL confirm the importance of PpgL in P. aeruginosa pathogenesis. These results suggest that PpgL is a potential target for developing new agents against the diseases caused by P. aeruginosa.

Mechanistic insights into the allosteric regulation of Pseudomonas aeruginosa aspartate kinase.

In plants and microorganisms, aspartate kinase (AK) catalyzes an initial commitment step of the aspartate family amino acid biosynthesis. Owing to various structural organizations, AKs from different species show tremendous diversity and complex allosteric controls. We report the crystal structure of AK from Pseudomonas aeruginosa (PaAK), a typical α2ß2 hetero-tetrameric enzyme, in complex with inhibitory effectors. Distinctive features of PaAK are revealed by structural and biochemical analyses. Essentially, the open conformation of Lys-/Thr-bound PaAK structure clarifies the inhibitory mechanism of α2ß2-type AK. Moreover, the various inhibitory effectors of PaAK have been identified and a general amino acid effector motif of AK family is described.

Host-derived peptide signals regulate Pseudomonas aeruginosa virulence stress via the ParRS and CprRS two-component systems.

Pseudomonas aeruginosa, a versatile bacterium, has dual significance because of its beneficial roles in environmental soil processes and its detrimental effects as a nosocomial pathogen that causes clinical infections. Understanding adaptability to environmental stress is essential. This investigation delves into the complex interplay of two-component system (TCS), specifically ParRS and CprRS, as P. aeruginosa interprets host signals and navigates stress challenges. In this study, through phenotypic and proteomic analyses, the nuanced contributions of ParRS and CprRS to the pathogenesis and resilience mechanisms were elucidated. Furthermore, the indispensable roles of the ParS and CprS extracellular sensor domains in orchestrating signal perception remain unknown. Structural revelations imply a remarkable convergence of TCS sensors in interacting with host peptides, suggesting evolutionary strategies for bacterial adaptation. This pioneering work not only established links between cationic antimicrobial peptide (CAMP) resistance-associated TCSs and virulence modulation in nosocomial bacteria, but also transcended conventional boundaries. These implications extend beyond clinical resistance, permeating into the realm of soil revitalization and environmental guardianship. As it unveils P. aeruginosa intricacies, this study assumes a mantle of guiding strategies to mitigate clinical hazards, harness environmental advantages, and propel sustainable solutions forward.

TiO2/carbonaceous nanocomposite from titanium-alginate coordination compound.

TiO2-based materials have been developing rapidly as eco-friendly photocatalysts, but the inherent defects limited their application, such as rapid recombination of photogenerated electrons and wide bandgap. To obtain high-efficient TiO2/carbonaceous photocatalysts (TiO2/C), we prepared the nanocomposite by carbonizing titanium alginate coordination compound and studied their photocatalytic performance against methylene blue (MB) under simulated sunlight irradiation. The resultant nanocomposites were characterized by FT-IR, XPS, XRD, SEM-EDS, TG-DTG, UV-DRS, and N2 adsorption-desorption analysis. The carbon mainly existed in the outer layer of TiO2/C composites, contributing to the optical sensibilization. As a result, the degradation efficiency of sample TiO2/C-20 to MB could reach 97.47% within 15 min under simulated sunlight. The samples also possessed high stability, proved by the 0.72% reduction in photodegradation ratio after five cyclic tests. The present study proved the feasibility of preparing photocatalyst from titanium-alginate coordination compound and provided an extensible approach for preparing high-efficiency photocatalysts from a polysaccharide-based coordination compound.

Granulomatous Inflammation of Greater Omentum Caused by a Migrating Fishbone.

Fishbone is the most common ingested gastrointestinal foreign matter and is less than 1% perforate. However, a fishbone penetrating the gastrointestinal tract and causing granulomatous inflammation of the greater omentum with local suppuration is not common. Because of the nonspecific clinical symptoms, gastrointestinal perforation may be manifested only as dull abdominal pain, which is often ignored and timely clinical treatment may be delayed. We report a case of a 61-year male who experienced intermittent right median ventral abdominal pain for half a year. These symptoms were the result of granulomatous inflammation of the greater omentum with local suppuration caused by a migrating fishbone (3.5 cm in length). Finally, the fishbone was removed by exploratory laparotomy. Key Words: Fishbone, Gastrointestinal perforation, Greater omentum, Granulomatous inflammation, Laparotomy.

Nucleotide binding as an allosteric regulatory mechanism for Akkermansia muciniphila ß-N-acetylhexosaminidase Am2136.

ß-N-acetylhexosaminidases (EC3.2.1.52), which belong to the glycosyl hydrolase family GH20, are important enzymes for oligosaccharides modification. Numerous microbial ß-N-acetylhexosaminidases have been investigated for applications in biology, biomedicine and biotechnology. Akkermansia muciniphila is an anaerobic intestinal commensal bacterium which possesses specific ß-N-acetylhexosaminidases for gut mucosal layer colonization and mucin degradation. In this study, we assessed the in vitro mucin glycan cleavage activity of the A. muciniphila ß-N-acetylhexosaminidase Am2136 and demonstrated its ability that hydrolyzing the ß-linkages joining N-acetylglucosamine to a wide variety of aglycone residues, which indicated that Am2136 may be a generalist ß-N-acetylhexosaminidase. Structural and enzyme activity assay experiments allowed us to probe the essential function of the inter-domain interactions in ß23-ß33. Importantly, we revealed that the hydrolysis activity of Am2136 was enhanced by nucleotides. We further speculated that this activation mechanism might be associated with the conformational motions between domain III and IV. To our knowledge, this is the first report of nucleotide effector regulated ß-N-acetylhexosaminidase, to reveal its novel biological functions. These findings contribute to understanding the distinct properties within the GH20 family and lay a certain foundation to develop controllable glycan hydrolyzing catalysts.Abbreviations: OD600 - optical cell densities at 600 nm; LB - Luria-Bertani; IPTG - isopropyl ß-D-1-thiogalactopyranoside; PMSF - phenylmethanesulfonyl fluoride; rmsd - root mean square deviation; GlcNAc - N-acetyl-ß-D-glucosamine; GalNAc - N-acetyl-ß-D-galactosamine; Gal - galactose.

MiR-22-3p Suppresses Cell Migration and Invasion by Targeting PLAGL2 in Breast Cancer.

OBJECTIVE: To investigate the expression of miR-22-3p in breast cancer and the mechanism of targeting PLAGL2 to inhibit the invasion and migration in human breast cancer. STUDY DESIGN: An experimental study. PLACE AND DURATION OF STUDY: Department of Oncology and Department of General Surgery, The People's Hospital of China Three Gorges University, China, from March 2019 to December 2020. METHODOLOGY: The miR-22-3p expression level in 41 paired human primary breast invasive ductal carcinoma tissues and para-cancer tissues was obtained by real-time fluorescence quantitative reverse transcriptase PCR (qRT-PCR). The effect of miR-22-3p on the proliferation of breast cancer cells was detected by growth curve method. Online software TargetScan was used to predict the target genes of miR-22-3p. The prediction results were verified by luciferase reporter gene assay and qRT⁃PCR. RESULTS: MiR-22-3p expression was significantly decreased in the breast cancer tissues than in para⁃carcinoma normal breast tissues (p<0.05). Over-expression of miR-22-3p can inhibit the proliferation of MCF-7 cells significantly. Pleomorphic adenoma gene-like protein 2(PLAGL2) is the predicted target gene of miR-22-3p. MiR-22-3p binds to its predicted target gene PLAGL2-3'UTR. The expression of miR-22-3p was negatively correlated with PLAGL2 in MCF-7 cells. CONCLUSION: MiR-22-3p could suppress the proliferation of breast cancer by targeting PLAGL2. This suggests that miR-22-3p may be a strategy of choice for targeted therapy of breast cancer. Key Words: Breast cancer, MiR-22-3p, PLAGL2, Cell proliferation.

Structural and molecular dynamic studies of Pseudomonas aeruginosa OdaA reveal the regulation role of a C-terminal hinge element.

BACKGROUND: Crotonase superfamily members exhibit great catalytic diversity towards various acyl-CoA substrates. A common CoA moiety binding pattern is usually observed in this family, understanding the substrate-binding mechanism would facilitate the rational engineering of crotonases for improved properties. METHODS: We applied X-ray crystallography to investigate a putative enoyl-CoA hydratase/isomerase OdaA in Pseudomonas aeruginosa. Thermal shift assay (TSA) were performed to explore the binding of OdaA with CoA thioester substrates. Furthermore, we performed molecular dynamics (MD) simulations to elucidate the dynamics of its CoA-binding site. RESULTS: We solved the crystal structures of the apo and CoA-bound OdaA. Thermal shift assay (TSA) showed that CoA thioester substrates bind to OdaA with a different degree. MD simulations demonstrated that the C-terminal alpha helix underwent a structural transition and a hinge region would associate with this conformational change. CONCLUSIONS: TSA in combination with MD simulations elucidate that the dynamics of C-terminal alpha helix in CoA-binding, and a hinge region play an important role in conformational change. GENERAL SIGNIFICANCE: Those results help to extend our knowledge about the nature of crotonases and would be informative for future mechanistic studies and industry applications.

Structural analysis of the sulfatase AmAS from Akkermansia muciniphila.

Akkermansia muciniphila, an anaerobic Gram-negative bacterium, is a major intestinal commensal bacterium that can modulate the host immune response. It colonizes the mucosal layer and produces nutrients for the gut mucosa and other commensal bacteria. It is believed that mucin desulfation is the rate-limiting step in the mucin-degradation process, and bacterial sulfatases that carry out mucin desulfation have been well studied. However, little is known about the structural characteristics of A. muciniphila sulfatases. Here, the crystal structure of the premature form of the A. muciniphila sulfatase AmAS was determined. Structural analysis combined with docking experiments defined the critical active-site residues that are responsible for catalysis. The loop regions I-V were proposed to be essential for substrate binding. Structure-based sequence alignment and structural superposition allow further elucidation of how different subclasses of formylglycine-dependent sulfatases (FGly sulfatases) adopt the same catalytic mechanism but exhibit diverse substrate specificities. These results advance the understanding of the substrate-recognition mechanisms of A. muciniphila FGly-type sulfatases. Structural variations around the active sites account for the different substrate-binding properties. These results will enhance the understanding of the roles of bacterial sulfatases in the metabolism of glycans and host-microbe interactions in the human gut environment.

Impacts of Cultural Diversity on Carbon Emission Effects: From the Perspective of Environmental Regulations.

Cultural diversity is an issue not considered too often in traditional research on the influencing factors of carbon emission reduction to give full play to the effective participation of micro subjects in environmental regulation and to achieve the carbon emission reduction target. Aiming at the cultural diversity of micro subjects, this paper introduces the provincial dynamic index of cultural diversity and, from the perspective of environmental regulation, combines environmental regulation types such as energy regulation, economic regulation, and administrative regulation, to empirically study the impact of cultural difference on carbon emission reduction. We found that cultural diversity had a significant negative impact on carbon emission effects, and there is a one-way Granger causality between the two. Cultural diversity and environmental regulations exerted a synergistic impact on carbon emission effects. Through specific mechanism tests, the intermediary effect of environmental regulations was confirmed. Cultural diversity influenced carbon emission effects through the mediation of environmental regulations. From the perspective of the refined characteristics of different regions, possible cultural diversity in the southern region and regional energy consumption characteristics significantly affected carbon emission effects. On the basis of the conclusions reached in this empirical research, we put forward the following policy suggestions: emphasis should be placed on the function of culture and other non-institutional factors in the practice of environmental regulations; bottom-up environmental protection incentives must be strengthened, and required expression channels should be perfected; the role of various environmental regulations must be given full play in the process of carbon emission reduction.

Structural and biochemical analysis of 1-Cys peroxiredoxin ScPrx1 from Saccharomyces cerevisiae mitochondria.

BACKGROUND: ScPrx1 is a yeast mitochondrial 1-Cys peroxiredoxins (Prx), a type of Prx enzyme which require thiol-containing reducing agents to resolve its peroxidatic cysteine. ScPrx1 plays important role in protection against oxidative stress. Mitochondrial thioredoxin ScTrx3 and glutathione have been reported to be the physiological electron donor for ScPrx1. However, the mechanism underlying their actions, especially the substrate recognition of ScPrx1 requires additional elucidation. METHODS: The structure of ScPrx1 was obtained through crystallization experiments. The oligomeric state of ScPrx1 was monitored by Blue-Native PAGE. Mutations were generated by the QuikChange PCR-based method. The ScPrx1 activity assay was carried out by measuring the change of 340 nm absorption of the NADPH oxidation. RESULTS: ScPrx1 exist as a homodimer in solution. The structure adopts a typical Prx-fold core which is preceded by an N-terminal ß-hairpin and has a C-terminal extension. Mutations (Glu94Ala, Arg198Ala and Trp126) close to the active site could enhance the catalytic efficiency of ScPrx1 while His83Ala and mutations on α4-ß6 region exhibited reduced activity. The biochemical data also show that the deletion or mutations on ScPrx1 C-terminal have 2-4.56 fold increased activity. CONCLUSION: We inferred that conformational changes of ScPrx1 C-terminal segment were important for its reaction, and the α4-ß6 loop regions around the ScPrx1 active sites were important for the catalytic function of ScPrx1. Collectively, these structural features provides a basis for understanding the diverse reductant species usage in different 1-Cys Prxs.

Structural characterization of a Δ3, Δ2-enoyl-CoA isomerase from Pseudomonas aeruginosa: implications for its involvement in unsaturated fatty acid metabolism.

Gene PA4980 from Pseudomonas aeruginosa encodes a putative enoyl-coenzyme A hydratase/isomerase that is associated with the function of the biofilm dispersion-inducing signal molecule cis-2-decenoic acid. To elucidate the role of PA4980 in cis-2-decenoic acid biosynthesis, we reported the crystal structure of its protein product at 2.39 Å. The structural analysis and substrate binding prediction suggest that it acts as a monofunctional enoyl-coenzyme A isomerase, implicating an alternative pathway of the cis-2-decenoic acid synthesis.

Lung Cancer with Concomitant Double Gene Mutation.

A patient presenting with concomitant epidermal growth factor receptor (EGFR) mutation and anaplastic lymphoma kinase (ALK) translocation is very rare. We report a non-small cell lung cancer (NSCLC) patient with concomitant EGFR (exon 19-del) mutation and ALK rearrangement. The positron emission tomography-computed tomography (PET-CT) scan revealed a highly metabolic mass lesion in the left lower lobe, measured 5.0 cm in the largest dimension in the S6 segment. Transbronchial lung biopsy (TBLB) showed the pathological diagnosis of invasive adenocarcinoma. Thus, the patient underwent left lower lobectomy and hilar-mediastina lymph node dissection (pT2N0M0). The tumor harbor an ALK (D5F3 +) rearrangement and EGFR (exon 19-del) mutation. The patient initially received four cycles of chemotherapy (pemetrexed and carboplatin), and achieved partial response (PR).

Structural and functional studies on Pseudomonas aeruginosa DspI: implications for its role in DSF biosynthesis.

DspI, a putative enoyl-coenzyme A (CoA) hydratase/isomerase, was proposed to be involved in the synthesis of cis-2-decenoic acid (CDA), a quorum sensing (QS) signal molecule in the pathogen Pseudomonas aeruginosa (P. aeruginosa). The present study provided a structural basis for the dehydration reaction mechanism of DspI during CDA synthesis. Structural analysis reveals that Glu126, Glu146, Cys127, Cys131 and Cys154 are important for its enzymatic function. Moreover, we show that the deletion of dspI results in a remarkable decreased in the pyoverdine production, flagella-dependent swarming motility, and biofilm dispersion as well as attenuated virulence in P. aeruginosa PA14. This study thus unravels the mechanism of DspI in diffusible signal factor (DSF) CDA biosynthesis, providing vital information for developing inhibitors that interfere with DSF associated pathogenicity in P. aeruginosa.

Author Correction: Structural and functional studies on Pseudomonas aeruginosa DspI: implications for its role in DSF biosynthesis.

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Nedaplatin-Induced Arrhythmia: Retrospective Analysis of Three Cases.

Nedaplatin (NDP) is a second-generation platinum derivative that was developed in Japan. Nowadays, it is being widely used in the management of lung cancer, esophageal cancer, head and neck cancers, especially when cisplatin and carboplatin cannot be tolerated or show drug resistance. To the best of our knowledge, there are few reported cases of NDP-induced bradycardia in the relevant medical literature. The current report presents three patients treated with NDP chemotherapy-induced serious arrhythmias. The three cases developed sinus tachycardia and atrial premature beats, complete left bundle branch block, and bigeminy ventricular premature contraction, in the second, sixth and second cycle, respectively. No one died of cardiac toxicity. These were treated with dexamethasone, 5 mg intravenous injection and diphenhydramine 20 mg, intramuscular injection. The heart rhythm returned to normal in 30 minutes, a day, and four days, respectively.

Primary Merkel Cell Carcinoma on the Cheek: Three Case Reports.

Merkel cell carcinoma (MCC) is a rare aggressive cutaneous neuroendocrine carcinoma that typically arises in sunexposed areas of the skin. Herein, we present three cases of primary MCC of the cheek. Case 1 had multiple nodules and mild swelling on the left cheek and eyelids, the patient did not receive any treatment and died after 10 months. Case 2 presented with nodule on patient's left cheek, which increased gradually. The patient was treated with surgical resection from the tumor edge 0.3 cm and skin flap transplantation, she died after 21 months. Case 3 presented with a nodule without any symptoms on patient's left cheek, she was treated with surgical resection and the left cheek was reconstructed with a free flap of tissue. Outpatient follow-up did not show any recurrence and metastasis. The authors report the clinical, histopathological, therapy, prognosis features of MCC, and reviewed with literature.

Structure-Function Relationship of Aminopeptidase P from Pseudomonas aeruginosa.

PepP is a virulence-associated gene in Pseudomonas aeruginosa, making it an attractive target for anti-P. aeruginosa drug development. The encoded protein, aminopeptidases P (Pa-PepP), is a type of X-prolyl peptidase that possesses diverse biological functions. The crystal structure verified its canonical pita-bread fold and functional tetrameric assembly, and the functional studies measured the influences of different metal ions on the activity. A trimetal manganese cluster was observed at the active site, elucidating the mechanism of inhibition by metal ions. Additionally, a loop extending from the active site appeared to be important for specific large-substrate binding. Based on the structural comparison and bacterial invasion assays, we showed that this non-conserved surface loop was critical for P. aeruginosa virulence. Taken together, these findings can extend our understanding of the catalytic mechanism and virulence-related functions of Pa-PepP and provide a solid foundation for the design of specific inhibitors against pathogenic-bacterial infections.