Protective effect and mechanism of nanoantimicrobial peptide ND-C14 against Streptococcus pneumoniae infection.

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is a common pathogen that causes bacterial pneumonia. However, with increasing bacterial resistance, there is an urgent need to develop new drugs to treat S. pneumoniae infections. Nanodefensin with a 14-carbon saturated fatty acid (ND-C14) is a novel nanoantimicrobial peptide designed by modifying myristic acid at the C-terminus of human α-defensin 5 (HD5) via an amide bond. However, it is unclear whether ND-C14 is effective against lung infections caused by S. pneumoniae. METHODS: In vitro, three groups were established, including the control group, and the HD5 and ND-C14 treatment groups. A virtual colony-count assay was used to evaluate the antibacterial activity of HD5 and ND-C14 against S. pneumoniae. The morphological changes of S. pneumoniae treated with HD5 or ND-C14 were observed by scanning electron microscopy. In vivo, mice were divided into sham, vehicle, and ND-C14 treatment groups. Mice in the sham group were treated with 25 µL of phosphate-buffered saline (PBS). Mice in the vehicle and ND-C14 treatment groups were treated with intratracheal instillation of 25 µL of bacterial suspension with 2×108 CFU/mL (total bacterial count: 5×106 CFU), and then the mice were given 25 µL PBS or intratracheally injected with 25 µL of ND-C14 (including 20 µg or 50 µg), respectively. Survival rates were evaluated in the vehicle and ND-C14 treatment groups. Bacterial burden in the blood and bronchoalveolar lavage fluid were counted. The lung histology of the mice was assessed. A propidium iodide uptake assay was used to clarify the destructive effect of ND-C14 against S. pneumoniae. RESULTS: Compared with HD5, ND-C14 had a better bactericidal effect against S. pneumoniae because of its stronger ability to destroy the membrane structure of S. pneumoniae in vitro. In vivo, ND-C14 significantly delayed the death time and improved the survival rate of mice infected with S. pneumoniae. ND-C14 reduced bacterial burden and lung tissue injury. Moreover, ND-C14 had a membrane permeation effect on S. pneumoniae, and its destructive ability increased with increasing ND-C14 concentration. CONCLUSION: The ND-C14 may improve bactericidal effects on S. pneumoniae both in vitro and in vivo.

RNA-seq revealed the anti-pyroptotic effect of suramin by suppressing NLRP3/caspase-1/GSDMD pathway in LPS-induced MH-S alveolar macrophages.

BACKGROUND: Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), acting as one common sepsis-associated organ injury, induces uncontrolled and self-amplifies pulmonary inflammation. Given the lack of clinically effective approaches, the mortality rate of it still remains high. Suramin(SUR), as an antiparasitic drug initially, was found to ameliorate sepsis associated ALI in our previous work. However, the underlying mechanism of its protective effects has not been clarified. Pyroptosis, categorized as an inflammatory form of programmed cell death, could aggravate lung inflammatory responses via inducing alveolar macrophages (AM) pyroptosis. METHODS: MH-S AM cell line was stimulated with or without lipopolysaccharide (LPS) or suramin, and the differential expression genes (DEGs) were excavated using RNA sequencing (RNA-seq). To identify the regulatory roles of these genes, pyroptosis-related genes (PRGs), GO/KEGG and GSEA analysis were conducted. We also performed WB, qRTPCR and ELISA to validate the RNA-seq results and further expound the protective effect of suramin. RESULTS: 624 DEGs were identified between control (CON) and lipopolysaccharide (LPS) groups, and enrichment analysis of these genes revealed significantly enriched pathways that related to immune system and signal transduction. Meanwhile, 500 DEGs were identified in LPS/SUR+LPS group. In addition to the pathways mentioned above, IL-17 pathway and C-type lectin receptor signaling pathway were also enriched. All 6 pathways were connected with pyroptosis. Concurrently, the "DESeq2" R package was used to identify differentially expressed PRGs. Nod1, Nod2, interleukin (IL)-1b, IL-6, tumor necrosis factor (TNF), NLRP3 were upregulated under LPS stimulation. Then, in SUR+LPS group, Nod2, IL-6, IL-1b, NLRP3 were downregulated. The validation results of WB, qRT-PCR, and ELISA showed: the protein and mRNA expression levels of NLRP3, caspase-1, GSDMD and the concentrations of IL-1b, IL-18 were decreased when treated with suramin and LPS. CONCLUSION: Suramin could inhibit NLRP3/caspase-1/GSDMD canonical pyroptosis pathway in LPS-induced MH-S alveolar macrophages.

Optimized potassium application rate increases foxtail millet grain yield by improving photosynthetic carbohydrate metabolism.

Photosynthetic carbohydrate metabolism is an important biochemical process related to crop production and quality traits. Potassium (K) critically contributes to the process of photosynthetic carbon assimilation and carbohydrate metabolism. We explored the effects of potassium fertilization on physiological mechanisms including carbohydrate metabolism in foxtail millet and its yield. Field experiments were performed using two foxtail millet (Setaria italica L.) cultivars: 1) Jingu 21 (low-K sensitive); and 2) Zhangza 10 (low-K tolerant). Effect of five different potassium fertilizer (K2O) rates (0, 60, 120, 180, and 240 kg·hm-2) were tested in two consecutive years, 2020 and 2021. We found that potassium application significantly increases the K content, dry matter accumulation and yield. Jingu 21 and Zhangza 10 had maximum yields at 180 kg·hm-2 K application, which were 29.91% and 31.51% larger than without K application, respectively. Excessive K application (K240) did not further improve their yields. The suitable K fertilizer application of Jingu 21 and Zhangza 10 are 195.25-204.27 and 173.95-175.87 kg·K2O·hm-2, respectively. The net photosynthetic rate (Pn), ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco), phosphoenolpyruvate carboxylase (PEPC), and fructose-1,6-bisphosphatase (FBPase) were positively correlated with the potassium content. Potassium application improved the availability of carbon sources for carbohydrate synthesis. Compared with the K0 treatment, variations in the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SuSy) in potassium-treated Jingu 21 (K60, K120, K180, and K240) were 17.94%-89.93% and 22.48%-182.10%, respectively, which were greater than those of Zhangza 10 (11.34%-71.12% and 16.18%-109.13%, respectively) and indicate that Jingu 21 is more sensitive to potassium application. The sucrose contents in the Jingu 21 and Zhangza 10 grains were 0.97%-1.15% and 1.04%-1.23%, respectively. The starch contents were 28.99%-37.75% and 24.81%-34.62%, respectively. The sucrose: ratio of Jingu 21 was smaller than that of Zhangza 10, indicating that Jingu 21 utilized nutrients better than Zhangza 10. Stepwise regression and path analysis showed that leaf and grain SuSy activity, by coordinating the source-sink relationship, have the greatest direct effect on Jingu 21 yield, whereas leaf SuSy activity, by promoting the generation of photosynthates at the source leaf, plays a leading role in Zhangza 10 yield increase. In conclusion, optimized K application can increase foxtail millet grain yield by improving photosynthesis and promoting carbohydrate accumulation and distribution.

LncRNA UCA1 epigenetically suppresses APAF1 expression to mediate the protective effect of sevoflurane against myocardial ischemia-reperfusion injury.

Myocardial ischemia-reperfusion injury (MI/RI) is a leading cause of death globally. Whereas some long noncoding RNAs (lncRNAs) are known to participate in the progression of MI/RI, the role of urothelial carcinoma associated 1 (UCA1) in conjunction with sevoflurane treatment remains largely unknown. H9C2 cardiomyocytes were subjected to hypoxia/reoxygenation (H/R) to establish an in vitro MI/RI model, and sevoflurane was then added. Cell viability, apoptosis, SOD activity, and MDA levels were measured. Levels of inflammatory cytokines and methylation of apoptosis protease-activating factor 1 (APAF1) were determined. Interactions among lncRNA UCA1, enhancer of zeste homologue 2 (EZH2), DNA methyltransferase-1 (DNMT1), and APAF1 were analyzed. After H/R treatment, the viability of H9C2 cardiomyocytes decreased and apoptosis rate, oxidative stress factor levels, inflammatory cytokine levels, and apoptosis-related protein levels all increased. Sevoflurane treatment reversed these changes. LncRNA UCA1 knockdown attenuated the therapeutic effect of sevoflurane on H/R-treated cardiomyocytes, and silencing of APAF1 reversed this role of UCA1 knockdown. Moreover, lncRNA UCA1 recruited DNMT1 through EZH2, thus promoting methylation of the APAF1 promoter region. LncRNA UCA1 recruits DNMT1 to promote methylation of the APAF1 promoter through EZH2, thus strengthening the protective effect of sevoflurane on H/R-induced cardiomyocyte injury.

The impact of pain and opioids use on survival in cancer patients: Results from a population-based cohort study and a meta-analysis.

The study aimed to explore whether cancer-related pain and opioids use are associated with the survival of cancer patients, and perform a cohort study and a meta-analysis to quantify the magnitude of any association.A retrospective cohort study was performed to analyze the impact of pain level, and opioids use on cancer-specific survival (CSS) in advanced cancer patients. Patients and relevant medical records were selected from the registry of the Radiation and chemotherapy division of Ningbo First Hospital between June 2013 and October 2017. Hazard ratios (HRs) and 95% confidential intervals (CIs) for CSS by opioids use were calculated by univariate and multivariate Cox regression analyses. The systematic review included relevant studies published before October 2018. The combined HRs and 95% CIs for overall survival (OS) and progression-free survival (PFS) were calculated using random-effect models.A total of consecutive 203 cancer patients were included in the cohort study. Kaplan-Meier curves indicate a negative association between CSS and cancer-related pain or opioids requirement, but less evidence of an association with the dose of opioids use. Multivariate models revealed that the pain level and opioids requirement were associated with shorter CSS, after adjusting for significant covariates. The results of the meta-analysis indicated that postoperative opioids use had a poor effect on PFS, and opioids use for cancer-related pain was associated with poor OS in cancer patients, while intraoperative opioids use was not associated with cancer survival.We concluded that cancer-related pain and opioids requirements are associated with poor survival in advanced cancer patients, and postoperative opioids use and opioids use for cancer-related pain may have an adverse effect on the survival of cancer patients.

Inverse Correlation Between Plasma Sphingosine-1-Phosphate and Ceramide Concentrations in Septic Patients and Their Utility in Predicting Mortality.

INTRODUCTION: The aim of this study was to investigate the correlation between plasma sphingosine-1-phosphate (S1P) and ceramide concentrations in sepsis, and the possible mechanisms for altered expression. METHODS: Plasma S1P and ceramide concentrations were measured by HPLC-ESI-MS/MS. HLA-DR (human leukocyte antigen-DR) expression on peripheral blood mononuclear cells was examined by flow cytometry. Platelet sphingosine kinases 1/2 (SphK1/2) mRNA expression, protein content, and enzyme activities were determined by qRT-PCR, western blot, and commercial enzyme assay kits, respectively. RESULTS: Compared with healthy and ICU controls, septic patients had significantly decreased plasma S1P but increased ceramide concentrations (P < 0.05). S1P concentration was negatively associated with the ceramide concentration in the septic patients (r = -0.36, P < 0.05). Linear regression analysis found that plasma S1P and ceramide were linked not only to sequential (sepsis-related) organ failure assessment (SOFA) score but also the HLA-DR expression on circulating monocytes. An receiver operating characteristic analysis, including S1P, ceramide, SOFA score and HLA-DR, showed integrated analysis of S1P and ceramide as the better powerful predictors of septic lethality with area under the curve value of 0.95. More importantly, we found the platelet SphKs activities and the expression levels of SphK1 were significantly decreased in septic patients (P < 0.05). Linear regression analysis revealed platelet SphKs activity was positively associated with the plasma S1P concentration of the septic patients (r = -0.41, P = 0.02). CONCLUSIONS: Integrated analysis of plasma S1P and ceramide predict septic mortality with high accuracy. The decreased platelet SphK1 expression and subsequent reduced SphKs activity might be responsible for the decreased plasma S1P levels during sepsis.

Upregulation of miR-137 protects anesthesia-induced hippocampal neurodegeneration.

PURPOSE: Ketamine is commonly used in pediatric anesthesia but may cause neurodegeneration in young brains. The aim of the study is to use an animal model to characterize the role of microRNA 137 (miR-137) in ketamine-induced neurodegeneration in neonatal hippocampus. METHODS: Young Sprague-Dawley Rats (1 month old) was systemically administrated with ketamine (75 mg/kg) for 3 days. TUNEL assay was used to assess the ketamine-induced neurodegeneration of hippocampal CA1 neurons, quantitative real-time PCR (qRT-PCR) to assess the expression of miR-137 and Morris water maze test (MWM) to assess the damaged memory function. Alternatively, lentivirus over-expressing miR-137 was injected into hippocampus before ketamine administration, and the subsequent effects of miR-137 upregulation on ketamine-induced hippocampal neurodegeneration and memory dysfunction were investigated. Furthermore, the direct downstream target of miR-137, CDC42, was down-regulated by siRNA injection into hippocampus. The effects of CDC42 inhibition on hippocampal apoptosis and memory function were also investigated. RESULTS: Excessive ketamine treatment resulted in severe apoptosis in hippocampal CA1 neurons, downregulation of miR-137 in hippocampus and significant long-term memory dysfunction. Conversely, pre-treatment of overexpressing miR-137 protected hippocampal neurodegeneration and memory loss. The molecular target of miR-137, CDC42 was down-regulated by ketamine in hippocampus. Knocking down hippocampal CDC42 exerted an apoptotic effect on hippocampal neurons and memory loss, similar to the effect of ketamine treatment. CONCLUSIONS: Our results demonstrated that miR-137 played an important role in regulating ketamine induced hippocampal neurodegeneration, possibly through CDC42.