Turning cationic antimicrobial peptide KR-12 into self-assembled nanobiotics with potent bacterial killing and LPS neutralizing activities.

Gram-negative sepsis has become a substantial and escalating global healthcare challenge due to the growing antibiotic resistance crisis and the sluggish development of new antibiotics. LL-37, a unique Cathelicidin species found in humans, exhibits a wide range of bioactive properties, including direct bactericidal effects, inflammation regulation, and LPS neutralization. KR-12, the smallest yet potent peptide fragment of LL-37, has been modified to create more effective antimicrobials. In this study, we designed two myristoylated derivatives of KR-12, referred to as Myr-KR-12N and Myr-KR-12C. These derivatives displayed remarkable ability to spontaneously assemble into nanoparticles when mixed with deionized water. Myristoylated KR-12 derivatives exhibited broad-spectrum and intensified bactericidal activity by disrupting bacterial cell membranes. In particular, Myr-KR-12N showed superior capability to rescue mice from lethal E. coli-induced sepsis in comparison with the conventional antibiotic meropenem. We also confirmed that the myristoylated KR-12 nanobiotic possesses significant LPS binding capacity and effectively reduces inflammation in vitro. In an in vivo context, Myr-KR-12N outperformed polymyxin B in rescuing mice from LPS-induced sepsis. Crucially, toxicological assessments revealed that neither Myr-KR-12N nor Myr-KR-12C nanobiotics induced meaningful hemolysis or caused damage to the liver and kidneys. Collectively, our study has yielded an innovative nanobiotic with dual capabilities of bactericidal action and LPS-neutralization, offering substantial promise for advancing the clinical translation of antimicrobial peptides and the development of novel antibiotics. This addresses the critical need for effective solutions to combat Gram-negative sepsis, a pressing global medical challenge.

Identification of module genes and functional pathway analysis in septic shock subtypes by integrated bioinformatics analysis.

BACKGROUND: The present study aimed to identify the module genes and key gene functions and biological pathways of septic shock (SS) through integrated bioinformatics analysis. METHODS: In the study, we performed batch correction and principal component analysis on 282 SS samples and 79 normal control samples in three datasets, GSE26440, GSE95233 and GSE57065, to obtain a combined corrected gene expression matrix containing 21,654 transcripts. Patients with SS were then divided into three molecular subtypes according to sample subtyping analysis. RESULTS: By analyzing the demographic characteristics of the different subtypes, we found no statistically significant differences in gender ratio and age composition among the three groups. Then, three subtypes of differentially expressed genes (DEGs) and specific upregulated DEGs (SDEGs) were identified by differential gene expression analysis. We found 7361 DEGs in the type I group, 5594 DEGs in the type II group, and 7159 DEGs in the type III group. There were 1698 SDEGs in the type I group, 2443 in the type II group, and 1831 in the type III group. In addition, we analyzed the correlation between the expression data of 5972 SDEGs in the three subtypes and the gender and age of 227 patients, constructed a weighted gene co-expression network, and identified 11 gene modules, among which the module with the highest correlation with gender ratio was MEgrey. The modules with the highest correlation with age composition were MEgrey60 and MElightyellow. Then, by analyzing the differences in module genes among different subgroups of SS, we obtained the differential expression of 11 module genes in four groups: type I, type II, type III and the control group. Finally, we analyzed the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment of all module DEGs, and the GO function and KEGG pathway enrichment of different module genes were different. CONCLUSIONS: Our findings aim to identify the specific genes and intrinsic molecular functional pathways of SS subtypes, as well as further explore the genetic and molecular pathophysiological mechanisms of SS.

Clinical Features and Risk Factors of Mortality in Patients with Posterior Reversible Encephalopathy Syndrome.

Objective: Although the prognosis of posterior reversible encephalopathy syndrome (PRES) is usually favourable and most patients wholly recover, the disorder can result in death in some patients. To date, the data on clinical features and risk factors for death are still lacking; therefore, we aim to investigate the clinical features and long-term prognostic risk factors of PRES in the present study. Methods: The patients with PRES were identified from the First Affiliated Hospital of Zhengzhou University from June 2011 to June 2020. Clinical characteristics, laboratory tests, magnetic resonance imaging examinations, and treatment of all patients were analyzed retrospectively. All patients were followed up by telephone. Finally, the patients were divided into the survival group and death group for prognosis analysis. Results: A total of 92 patients with PRES were included; 84.8% of whom were female, with an average age of 25.4 (5-66) years at the onset of PRES. Epilepsy was the main clinical manifestation (72.8%). The in-hospital mortality rate was 2.17%. The 3-year all-cause survival rate for PRES patients was 86%. In univariate analysis, patients with systemic lupus erythematosus (P = 0.027) and blood transfusion history within 1 month before onset (P = 0.027), need for dialysis (P ≤ 0.001), nephritis (P = 0.010), stroke (P = 0.016), and heart failure (P = 0.016) were associated with death. In multivariate analysis, we found that heart failure (OR = 0.095, 95% CI 0.020 to 0.441) and stroke (OR = 0.033, 95% CI 0.002 to 0.467) were independent risk factors for death in PRES patients, while pregnancy was a protective factor for death in PRES patients (OR = 7.978, 95% CI 1.446 to 44.006). Conclusions: Our results indicate that PRES could be considered as a sign of a very high-risk patient. We also demonstrated that heart failure and stroke were independent risk factors for death in patients with PRES; moreover, pregnancy was a protective factor.

Self-Assembling Myristoylated Human α-Defensin 5 as a Next-Generation Nanobiotics Potentiates Therapeutic Efficacy in Bacterial Infection.

The increasing prevalence of antibacterial resistance globally underscores the urgent need to the update of antibiotics. Here, we describe a strategy for inducing the self-assembly of a host-defense antimicrobial peptide (AMP) into nanoparticle antibiotics (termed nanobiotics) with significantly improved pharmacological properties. Our strategy involves the myristoylation of human α-defensin 5 (HD5) as a therapeutic target and subsequent self-assembly in aqueous media in the absence of exogenous excipients. Compared with its parent HD5, the C-terminally myristoylated HD5 (HD5-myr)-assembled nanobiotic exhibited significantly enhanced broad-spectrum bactericidal activity in vitro. Mechanistically, it selectively killed Escherichia coli ( E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) through disruption of the cell wall and/or membrane structure. The in vivo results further demonstrated that the HD5-myr nanobiotic protected against skin infection by MRSA and rescued mice from E. coli-induced sepsis by lowering the systemic bacterial burden and alleviating organ damage. The self-assembled HD5-myr nanobiotic also showed negligible hemolytic activity and substantially low toxicity in animals. Our findings validate this design rationale as a simple yet versatile strategy for generating AMP-derived nanobiotics with excellent in vivo tolerability. This advancement will likely have a broad impact on antibiotic discovery and development efforts aimed at combating antibacterial resistance.

Sphingosine-1-phosphate Receptor 2 Signaling Promotes Caspase-11-dependent Macrophage Pyroptosis and Worsens Escherichia coli Sepsis Outcome.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Pyroptosis, a type of proinflammatory programmed cell death, drives cytokine storm. Caspase-11-dependent macrophage pyroptosis contributes to mortality during sepsis. Sphingosine-1-phosphate receptor 2 (S1PR2) signaling can amplify interleukin-1ß secretion in endotoxin-induced inflammation. Here, we hypothesized that S1PR2 signaling increases caspase-11-dependent macrophage pyroptosis and worsens Gram-negative sepsis outcome. METHODS: A Gram-negative sepsis model was induced through intraperitoneal injection of Escherichia coli. Primary peritoneal macrophages isolated from wild-type, S1pr2-deficient (S1pr2), or nucleotide-binding oligomerization domain-like receptor protein-3-deficient mice were treated with E. coli. Caspase-11 activation, macrophage pyroptosis, and Ras homolog gene family, member A-guanosine triphosphate levels were assessed in those cells. Additionally, monocyte caspase-4 (an analog of caspase-11) expression and its correlation with S1PR2 expression were determined in patients with Gram-negative sepsis (n = 11). RESULTS: Genetic deficiency of S1PR2 significantly improved survival rate (2/10 [20%] in wild-type vs. 7/10 [70%] in S1pr2, P = 0.004) and decreased peritoneal macrophage pyroptosis (pyroptosis rate: 35 ± 3% in wild-type vs. 10 ± 3% in S1pr2, P < 0.001). Decreased caspase-11 activation in S1PR2 deficiency cells contributed to the reduced macrophage pyroptosis. In addition, RhoA inhibitor abrogated the amplified caspase-11 activation in wild-type or S1PR2-overexpressing cells. In patients with Gram-negative sepsis, caspase-4 increased significantly in monocytes compared to nonseptic controls and was positively correlated with S1PR2 (r = 0.636, P = 0.035). CONCLUSIONS: S1PR2 deficiency decreased macrophage pyroptosis and improved survival in E. coli sepsis. These beneficial effects were attributed to the decreased caspase-11 activation of S1PR2-deficient macrophages. S1PR2 and caspase-11 may be promising new targets for treatment of sepsis.

Effects of catalpol on ATPase and amino acids in gerbils with cerebral ischemia/reperfusion injury.

This study aimed to investigate the effects of catalpol on ATPase and amino acids in gerbils following cerebral ischemia/reperfusion (CI/R) injury. Gerbil model of CI/R was prepared by bilateral common carotid occlusion for 10 min followed by 6 h of reperfusion. Catalpol (5, 10 or 20 mg/kg per day) was injected intraperitoneally for 3 days before the carotid occlusion. Stroke index was measured during the reperfusion. ATPase activity, glutamate (Glu) and aspartate contents in brain tissue homogenate were examined. The results showed that catalpol significantly improved the stroke index compared with sham group (P < 0.05 or P < 0.01). Catalpol markedly increased the activities of Na(+)-K(+)-ATPase and Ca(2+)-ATPase (P < 0.05 or P < 0.01), and significantly decreased the content of Glu in brain tissue (P < 0.05 or P < 0.01). These data suggest that the efficacy of catalpol pretreatment on CI/R injury is associated with the enhancement of ATPase activity and the inhibition of excitatory amino acid toxicity.