scholarly journals Antimicrobial peptide LL-37 ameliorates a murine sepsis model via the induction of microvesicle release from neutrophils

2020 ◽  
Vol 26 (7) ◽  
pp. 565-579 ◽  
Author(s):  
Yumi Kumagai ◽  
Taisuke Murakami ◽  
Kuwahara-Arai ◽  
Toshiaki Iba ◽  
Johannes Reich ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Ex Vivo ◽  
Protective Action ◽  
Bacterial Load ◽  
Cecal Ligation ◽  
Mouse Bone Marrow ◽  
Cecal Ligation And Puncture ◽  
Sepsis Survivors ◽  
Antibacterial Potential

Sepsis is a life-threatening disease caused by systemic dys-regulated inflammatory response to infection. We previously revealed that LL-37, a human cathelicidin antimicrobial peptide, improves the survival of cecal ligation and puncture septic mice. Ectosomes, microvesicles released from neutrophils, are reported to be elevated in sepsis survivors; however, the functions of ectosomes in sepsis remain largely unknown. Therefore, we herein elucidated the protective action of LL-37 on sepsis, by focusing on LL-37-induced ectosome release in a cecal ligation and puncture model. The results demonstrated the enhancement of ectosome levels by LL-37 administration, accompanied by a reduction of bacterial load. Importantly, ectosomes isolated from LL-37-injected cecal ligation and puncture mice contained higher amounts of antimicrobial proteins/peptides and exhibited higher antibacterial activity, compared with those from PBS-injected cecal ligation and puncture mice, suggesting that LL-37 induces the release of ectosomes with antibacterial potential in vivo. Actually, LL-37 stimulated mouse bone-marrow neutrophils to release ectosomes ex vivo, and the LL-37-induced ectosomes possessed antibacterial potential. Furthermore, administration of LL-37-induced ectosomes reduced the bacterial load and improved the survival of cecal ligation and puncture mice. Together these observations suggest LL-37 induces the release of antimicrobial ectosomes in cecal ligation and puncture mice, thereby reducing the bacterial load and protecting mice from lethal septic conditions.

scholarly journals The Equine Antimicrobial Peptide eCATH1 Is Effective against the Facultative Intracellular Pathogen Rhodococcus equi in Mice

2013 ◽  
Vol 57 (10) ◽  
pp. 4615-4621 ◽  
Author(s):  
Margot Schlusselhuber ◽  
Riccardo Torelli ◽  
Cecilia Martini ◽  
Matthias Leippe ◽  
Vincent Cattoir ◽  
...  
Keyword(s):  
Body Weight ◽  
Antimicrobial Peptide ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Bacterial Load ◽  
Intracellular Localization ◽  
Rhodococcus Equi ◽  
Histopathological Analysis ◽  
Bacterial Cells

ABSTRACTRhodococcus equi, the causal agent of rhodococcosis, is a major pathogen of foals and is also responsible for severe infections in immunocompromised humans. Of great concern, strains resistant to currently used antibiotics have emerged. As the number of drugs that are efficientin vivois limited because of the intracellular localization of the bacterium inside macrophages, new active but cell-permeant drugs will be needed in the near future. In the present study, we evaluated, byin vitroandex vivoexperiments, the ability of the alpha-helical equine antimicrobial peptide eCATH1 to kill intracellular bacterial cells. Moreover, the therapeutic potential of the peptide was assessed in experimental rhodococcosis induced in mice, while thein vivotoxicity was evaluated by behavioral and histopathological analysis. The study revealed that eCATH1 significantly reduced the number of bacteria inside macrophages. Furthermore, the bactericidal potential of the peptide was maintainedin vivoat doses that appeared to have no visible deleterious effects for the mice even after 7 days of treatment. Indeed, daily subcutaneous injections of 1 mg/kg body weight of eCATH1 led to a significant reduction of the bacterial load in organs comparable to that obtained after treatment with 10 mg/kg body weight of rifampin. Interestingly, the combination of the peptide with rifampin showed a synergistic interaction in bothex vivoandin vivoexperiments. These results emphasize the therapeutic potential that eCATH1 represents in the treatment of rhodococcosis.

scholarly journals Protective Role of Coenzyme Q10 in Acute Sepsis-Induced Liver Injury in BALB/c Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Qian-wei Li ◽  
Qin Yang ◽  
Hong-Yang Liu ◽  
Yu-ling Wu ◽  
Yu-Hua Hao ◽  
...  
Keyword(s):  
Liver Injury ◽  
Coenzyme Q10 ◽  
Cecal Ligation ◽  
Protective Role ◽  
Hepatic Tissue ◽  
Control Group ◽  
Cecal Ligation And Puncture ◽  
Sequestosome 1

Sepsis increases the risk of the liver injury development. According to the research works, coenzyme Q10 exhibits hepatoprotective properties in vivo as well as in vitro. Current work aimed at investigating the protective impacts of coenzyme Q10 against liver injury in septic BALB/c mice. The male BALB/c mice were randomly segregated into 4 groups: the control group, the coenzyme Q10 treatment group, the puncture and cecal ligation group, and the coenzyme Q10+cecal ligation and puncture group. Cecal ligation and puncture was conducted after gavagaging the mice with coenzyme Q10 during two weeks. Following 48 h postcecal ligation and puncture, we estimated hepatic biochemical parameters and histopathological changes in hepatic tissue. We evaluated the expression of factors associated with autophagy, pyroptosis, and inflammation. Findings indicated that coenzyme Q10 decreased the plasma levels in alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase in the cecal ligation and puncture group. Coenzyme Q10 significantly inhibited the elevation of sequestosome-1, interleukin-1β, oligomerization domain-like receptor 3 and nucleotide-binding, interleukin-6, and tumor necrosis factor-α expression levels; coenzyme Q10 also increased beclin 1 levels. Coenzyme Q10 might be a significant agent in the treatment of liver injury induced by sepsis.

scholarly journals BMX Represses Thrombin-PAR1–Mediated Endothelial Permeability and Vascular Leakage During Early Sepsis

2020 ◽  
Vol 126 (4) ◽  
pp. 471-485 ◽  
Author(s):  
Zhao Li ◽  
Mingzhu Yin ◽  
Haifeng Zhang ◽  
Weiming Ni ◽  
Richard W. Pierce ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cecal Ligation ◽  
Endothelial Permeability ◽  
Vascular Leakage ◽  
Lung Epithelial Cells ◽  
Negative Regulator ◽  
Cecal Ligation And Puncture ◽  
Early Sepsis

Rationale: BMX (bone marrow kinase on the X chromosome) is highly expressed in the arterial endothelium from the embryonic stage to the adult stage in mice. It is also expressed in microvessels and the lymphatics in response to pathological stimuli. However, its role in endothelial permeability and sepsis remains unknown. Objective: We aimed to delineate the function of BMX in thrombin-mediated endothelial permeability and the vascular leakage that occurs with sepsis in cecal ligation and puncture models. Methods and Results: The cecal ligation and puncture model was applied to WT (wild type) and BMX-KO (BMX global knockout) mice to induce sepsis. Meanwhile, the electric cell-substrate impedance sensing assay was used to detect transendothelial electrical resistance in vitro and, the modified Miles assay was used to evaluate vascular leakage in vivo. We showed that BMX loss caused lung injury and inflammation in early cecal ligation and puncture–induced sepsis. Disruption of BMX increased thrombin-mediated permeability in mice and cultured endothelial cells by 2- to 3-fold. The expression of BMX in macrophages, neutrophils, platelets, and lung epithelial cells was undetectable compared with that in endothelial cells, indicating that endothelium dysfunction, rather than leukocyte and platelet dysfunction, was involved in vascular permeability and sepsis. Mechanistically, biochemical and cellular analyses demonstrated that BMX specifically repressed thrombin-PAR1 (protease-activated receptor-1) signaling in endothelial cells by directly phosphorylating PAR1 and promoting its internalization and deactivation. Importantly, pretreatment with the selective PAR1 antagonist SCH79797 rescued BMX loss-mediated endothelial permeability and pulmonary leakage in early cecal ligation and puncture–induced sepsis. Conclusions: Acting as a negative regulator of PAR1, BMX promotes PAR1 internalization and signal inactivation through PAR1 phosphorylation. Moreover, BMX-mediated PAR1 internalization attenuates endothelial permeability to protect vascular leakage during early sepsis.

Activation of Notch Signaling Mediates Ex Vivo Expansion of Multilineage, Engrafting Murine Hematopoietic Progenitors From Embryonic Sources.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2321-2321
Author(s):  
Brandon K Hadland ◽  
Barbara Varnum-Finney ◽  
Irwin D. Bernstein
Keyword(s):  
Notch Signaling ◽  
Ex Vivo ◽  
Fetal Liver ◽  
Signal Pathways ◽  
Mouse Bone Marrow ◽  
Human Cord Blood ◽  
Hematopoietic Stem ◽  
Notch Activation

Abstract Abstract 2321 An important goal in the application of pluripotent stem cells (PSC) for therapeutic purposes is the derivation of hematopoietic stem and progenitor cells (HSPC) capable of efficient engraftment in vivo. Fundamental to achieving this goal is improved understanding of key signal pathways required to establish, maintain and expand HSPCs from embryonic sources. Ex vivo activation of Notch signaling in mouse bone marrow and human cord blood-derived HSC can facilitate expansion of rapidly engrafting multilineage progenitors, which has recently been translated for therapeutic purposes. In contrast, similar expansion of engrafting progenitors has not been successful from PSC. This prompted us to evaluate whether embryonic-derived HSPC have capacity to respond to ligand-induced Notch signaling ex vivo, and whether Notch activation could promote expansion of engrafting progenitors from these embryonic sources. We have examined the effects of ex vivo activation of Notch receptors by immobilized, exogenous Notch ligands on highly enriched populations of embryonic HSC and HSC precursors (pre-HSC) at various developmental stages. We find that activation of Notch by the ligand Delta1 within HSC/pre-HSC isolated from embryonic aorta-gonad-mesonephros (AGM) promotes expansion of progenitors with erythromyeloid colony forming potential and T/B-lymphoid potential in vitro, with concurrent expression of surface phenotypes resembling fetal liver-stage HSC. Furthermore, Notch activation in embryonic HSPC also mediates expansion of progenitors with rapidly engrafting myeloid and lymphoid capacity in irradiated mouse models. Our results demonstrate that embryonic stage HSPC have capacity to expand in response to Notch activation, and thus further studies comparing AGM- and PSC-derived hematopoietic precursors are needed to elucidate differences that may account for failure to expand HSPC from PSC. Disclosures: Bernstein: Seattle Genetics, Inc.: Consultancy.

scholarly journals DAP12 (KARAP) amplifies inflammation and increases mortality from endotoxemia and septic peritonitis

2005 ◽  
Vol 202 (3) ◽  
pp. 363-369 ◽  
Author(s):  
Isaiah R. Turnbull ◽  
Jonathan E. McDunn ◽  
Toshiyuki Takai ◽  
R. Reid Townsend ◽  
J. Perren Cobb ◽  
...  
Keyword(s):  
Septic Shock ◽  
Cytokine Production ◽  
Ex Vivo ◽  
Cecal Ligation ◽  
Wild Type ◽  
Macrophage Response ◽  
Cytokine Levels ◽  
Septic Peritonitis ◽  
Microbial Products

DAP12 (KARAP) is a transmembrane signaling adaptor for a family of innate immunoreceptors that have been shown to activate granulocytes and monocytes/macrophages, amplifying production of inflammatory cytokines. Contrasting with these data, recent studies suggest that DAP12 signaling has an inhibitory role in the macrophage response to microbial products (Hamerman, J.A., N.K. Tchao, C.A. Lowell, and L.L. Lanier. 2005. Nat. Immunol. 6:579–586). To determine the in vivo role for DAP12 signaling in inflammation, we measured the response of wild-type (WT) and DAP12−/− mice to septic shock. We show that DAP12−/− mice have improved survival from both endotoxemia and cecal ligation and puncture–induced septic shock. As compared with WT mice, DAP12−/− mice have decreased plasma cytokine levels and a decreased acute phase response during sepsis, but no defect in the recruitment of cells or bacterial control. In cells isolated after sepsis and stimulated ex vivo, DAP12 signaling augments lipopolysaccharide-mediated cytokine production. These data demonstrate that, during sepsis, DAP12 signaling augments the response to microbial products, amplifying inflammation and contributing to mortality.

scholarly journals Beneficial effect of STAT3 decoy oligodeoxynucleotide transfection on organ injury and mortality in mice with cecal ligation and puncture-induced sepsis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Samar Imbaby ◽  
Naoyuki Matsuda ◽  
Kengo Tomita ◽  
Kohshi Hattori ◽  
Sailesh Palikhe ◽  
...  
Keyword(s):  
Critical Role ◽  
Cecal Ligation ◽  
High Mobility ◽  
Organ Injury ◽  
Cecal Ligation And Puncture ◽  
Signal Transducers ◽  
Significant Survival ◽  
Upstream Kinase ◽  
Stat3 Decoy

Abstract Sepsis is a major clinical challenge with unacceptably high mortality. The signal transducers and activators of transcription (STAT) family of transcription factors is known to activate critical mediators of cytokine responses, and, among this family, STAT3 is implicated to be a key transcription factor in both immunity and inflammatory pathways. We investigated whether in vivo introduction of synthetic double-stranded STAT3 decoy oligodeoxynucleotides (ODNs) can provide benefits for reducing organ injury and mortality in mice with cecal ligation and puncture (CLP)-induced polymicrobial sepsis. We found that STAT3 was rapidly activated in major end-organ tissues following CLP, which was accompanied by activation of the upstream kinase JAK2. Transfection of STAT3 decoy ODNs downregulated pro-inflammatory cytokine/chemokine overproduction in CLP mice. Moreover, STAT3 decoy ODN transfection significantly reduced the increases in tissue mRNAs and proteins of high mobility group box 1 (HMGB1) and strongly suppressed the excessive elevation in serum HMGB1 levels in CLP mice. Finally, STAT3 decoy ODN administration minimized the development of sepsis-driven major end-organ injury and led to a significant survival advantage in mice after CLP. Our results suggest a critical role of STAT3 in the sepsis pathophysiology and the potential usefulness of STAT3 decoy ODNs for sepsis gene therapy.

scholarly journals Extracellular Tyrosyl-tRNA Synthetase Is a Potent Stimulator of Thrombocytopoiesis

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1476-1476
Author(s):  
Sachiko Kanaji ◽  
Taisuke Kanaji ◽  
My-Nuong Vo ◽  
Alessandro Zarpellon ◽  
Ryan Shapiro ◽  
...  
Keyword(s):  
Research Funding ◽  
Ex Vivo ◽  
Trna Synthetase ◽  
Mouse Bone Marrow ◽  
Dependent Manner ◽  
Hematopoietic Stem ◽  
Platelet Production ◽  
Equity Ownership

Abstract Aminoacyl-tRNA synthetases (aaRSs) are enzymes with a key role in the first step of protein synthesis by catalyzing the esterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. During evolution, eukaryotic aaRSs have acquired additional domains and motifs conferring non-canonical functions beyond translation, such as expressing multiple cytokine activities. Repurposing aaRSs often requires an activation step and the first reported example was for human tyrosyl-tRNA synthetase (YRS), which is abundant in platelets and released from their α-granules upon thrombin or arachidonic acid stimulation. As shown by previous work, activated YRS (YRSACT) - created by natural proteolysis, alternative splicing, or rational mutagenesis - can express the activity of different cytokines. In the current study, we demonstrate that recombinant YRSACT rendered active by the gain-of-function mutation Tyr341Ala exhibits a previously unrecognized role in megakaryocytopoiesis and thrombocytopoiesis. When administered in vivo in C57BL/6 wild type (WT) mice, recombinant YRSACT caused platelet increase both under baseline conditions as well as in a model of immune-mediated thrombocytopenia in which mice are made thrombocytopenic by injection of rat anti-mouse glycoprotein (GP) Ib monoclonal IgG. When WT mouse bone marrow (BM) cells were cultured ex vivo for 3 days, YRSACT treatment increased the number of megakaryocytes by 3.0-fold, particularly of megakaryocytes with 16N ploidy. This effect was independent of thrombopoietin (TPO) signaling because YRSACT could support the expansion of c-mpl-/- (TPO receptor knock-out) mouse megakaryocytes. YRSACT had no effect on purified mouse CD41+ or Sca1+ hematopoietic progenitor cells, indicating that YRS-dependent stimulation likely required the contribution of other cells present in BM cultures. When mouse BM cells were stimulated with different doses of YRSACT, the number of F4/80+ monocyte/macrophages as well as of megakaryocytes increased in a dose-dependent manner. Mechanistic analysis revealed YRSACT targets the Toll-like receptor (TLR) pathway signaling through MyD88 in monocyte/macrophages, thereby enhancing release of cytokines that influence megakaryocyte development. In vitro binding assay showed that YRSACT is capable of binding to TLR2 and TLR4. The effect of YRSACT was attenuated in the BM cells derived from TLR2-/- mice and was abolished in MyD88-/- mice. Among the cytokines with synthesis induced by YRSACT, IL-6 plays a pivotal role in megakaryocyte development. Thus, we tested the effect of YRSACT on megakaryocytes obtained by culturing BM cell derived from IL-6-/- mice and found that no effect was apparent. The stimulatory effect of YRSACT on megakaryocytopoiesis was confirmed with human CD41+ megakaryocyte progenitors differentiated from CD34+ hematopoietic stem cells derived from peripheral blood. In conclusion, we have documented a previously unrecognized activity of YRSACT that results in enhanced megakaryocytopoiesis and platelet production. These studies document a mechanistically distinct aaRS-directed hematological activity that highlights new potential approaches to stimulating platelet production for treating thrombocytopenia and for improving ex vivo preparation of platelet concentrates for transfusion. Disclosures Belani: aTyr Pharma: Consultancy, Equity Ownership, Patents & Royalties. Do:aTyr Pharma: Employment, Equity Ownership, Patents & Royalties. Yang:aTyr Pharma: Consultancy, Patents & Royalties, Research Funding. Schimmel:aTyr Pharma: Consultancy, Equity Ownership, Patents & Royalties, Research Funding.

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