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Endotoxemia induced by lipopolysaccharide (LPS) is an extremely severe syndrome identified by global activation of inflammatory responses. Neutrophil extracellular traps (NETs) play an important role in the development of endotoxemia. Histone hypercitrullination catalyzed by peptidylarginine deiminases (PADs) is a key step of NET formation. We have previously demonstrated that simultaneous inhibition of PAD2 and PAD4 with pan-PAD inhibitors can decrease NETosis and improve survival in a mouse model of LPS-induced endotoxic shock. However, the effects of PAD2 specific inhibition during NETosis and endotoxic shock are poorly understood. Therefore, in the present study, we aimed to investigate the effect of the specific PAD2 or PAD4 inhibitor on LPS-induced endotoxic shock in mice. We found that PAD2 inhibition but not PAD4 inhibition improves survival. Also, the levels of proinflammatory cytokines and NETosis were significantly reduced by PAD2 inhibitor. To our knowledge, this study demonstrates for the first time that PAD2 inhibition can reduce NETosis, decrease inflammatory cytokine production, and protect against endotoxin-induced lethality. Our findings provided a novel therapeutic strategy for the treatment of endotoxic shock. [ABSTRACT FROM AUTHOR]

We have found earlier that Tubastatin A (TubA), a selective inhibitor of histone deacetylase 6 (HDAC6), improves survival in a mouse model of lethal cecal ligation and puncture (CLP)-induced sepsis. However, the underlying mechanisms have not been fully established. This study sought to test the hypothesis that TubA could affect both lung and splenic functions. C57BL/6J mice were subjected to CLP, and randomized to receive either TubA (70 mg/kg) dissolved in dimethyl sulfoxide (DMSO), or DMSO alone, 1 h following CLP. Sham animals acted as control. Twenty-four hours later, lung tissue was harvested for pathological examination, and splenic tissue was harvested for bacterial colonization. In a parallel study, the spleen was collected 48 h following CLP, and single cell suspension was prepared. Splenocytes then underwent flow cytometry to analyze the immune cell population. RAW264.7 macrophages were treated with lipopolysaccharide (LPS) with or without the presence of TubA (10 μM) at 37 °C for 3 h to assess the effect on macrophage phagocytosis. We found that acute lung injury secondary to lethal sepsis was attenuated by TubA. Treatment with TubA restored the percentage of B lymphocytes, and significantly increased percentages of innate immune cells and macrophages compared to the vehicle-treated CLP group. Moreover, TubA significantly decreased the bacterial load in the spleen, and improved the phagocytic ability of RAW264.7 murine macrophages in vitro. Such findings may help to explain the beneficial effects of TubA treatment in a model of lethal sepsis, as previously reported. [ABSTRACT FROM AUTHOR]

AlGaInAs electroabsorption-modulated lasers (EMLs) fabricated by identical epitaxial layer technique are demonstrated. The EML device shows an infinite characteristic temperature when the temperature ranges from 20 o C to 30 o C. The integrated modulator has static extinction ratios of larger than 20 dB at a reverse bias voltage of − 2 V. The small signal modulation bandwidth of the modulator is larger than 11 GHz. At 10 Gb/s data modulation, the dynamic extinction ratio is about 9.5 dB in a back to back test configuration. Because only a simple fabrication procedure is needed, our EMLs are promising low cost light sources for optical fiber transmission applications. [ABSTRACT FROM AUTHOR]

Objective: Sepsis causes millions of deaths on a global scale annually. Activation of peptidylarginine deiminase (PAD) enzymes in sepsis causes citrullination of histones, which results in neutrophil extracellular trap formation and sepsis progression. This study evaluates pan-PAD inhibitor, Cl-amidine, in a model of lipopolysaccharide (LPS)-induced endotoxic shock in rabbits. We hypothesized that Cl-amidine would improve survival and attenuate kidney injury. Methods: In the survival model, rabbits were injected injected intravenously with 1 mg/kg of LPS, and then randomly assigned either to receive dimethyl sulfoxide (DMSO; 1 mcL/g) or Cl-amidine (10 mg/kg diluted in 1 mcL/g DMSO). They were then monitored for 14 days to evaluate survival. In the non-survival experiment, the same insult and treatment were administered, however; the animals were euthanized 12 hours after LPS injection for kidney harvest. Acute kidney injury (AKI) scoring was performed by a histopathologist who was blinded to the group assignment. Serial blood samples were also collected and compared. Results: Rabbits that received Cl-amidine had a higher survival (72%) compared with the rabbits that received DMSO (14%; p < 0.05). Cl-amidine-treated rabbits had lower (p < 0.05) histopathologic AKI scores, as well as plasma creatinine and blood urea nitrogen (BUN) levels 12 hours after insult. Conclusions: Pan-PAD inhibitor Cl-amidine improves survival and attenuates kidney injury in LPS-induced endotoxic shock in rabbits. [ABSTRACT FROM AUTHOR]

Immune cell death caused by neutrophil extracellular traps (NETs), referred to as NETosis, can contribute to the pathogenesis of endotoxemia and organ damage. Although the mechanisms by which infection induces NETosis and how that leads to organ dysfunction remain largely unknown, NET formation is often found following citrullination of histone H3 (CitH3) by peptidylarginine deiminase (PAD). We hypothesized that lipopolysaccharide (LPS)-induced activation of PAD and subsequent CitH3-mediated NET formation increases endothelial permeability and pulmonary dysfunction and, therefore, that inhibition of PAD can mitigate damage and improve survival in lethal endotoxemia. Here, we showed that treatment with YW3–56, a PAD2/PAD4 inhibitor, significantly diminished PAD activation, blocked LPS-induced pulmonary vascular leakage, alleviated acute lung injury, and improved survival in a mouse model of lethal LPS-induced endotoxemia. We found CitH3 in the bloodstream 30 min after intraperitoneal injection of LPS (35 mg/kg) into mice. Additionally, CitH3 production was induced in cultured neutrophils exposed to LPS, and NETs derived from these LPS-treated neutrophils increased the permeability of endothelial cells. However, YW3–56 reduced CitH3 production and NET formation by neutrophils following LPS exposure. Moreover, treatment with YW3–56 decreased the levels of circulating CitH3 and abolished neutrophil activation and NET formation in the lungs of mice with endotoxemia. These data suggest a novel mechanism by which PAD-NET-CitH3 can play a pivotal role in pulmonary vascular dysfunction and the pathogenesis of lethal endotoxemia. [ABSTRACT FROM AUTHOR]

Production of innate and adaptive immune cells from hematopoietic stem cells, and maturation of T lymphocytes are effective immune responses to fight severe microbial infection. In sepsis, this emergency myelopoiesis is damaged, leading to failure of bacterial clearance, and excessive stress-induced steroids cause immature T-lymphocyte apoptosis in thymus. We recently found that Cl-amidine, a peptidylarginine deiminase (PAD) inhibitor, improves survival in a mouse model of cecal ligation and puncture (CLP)-induced septic shock. In the present study we investigated how Cl-amidine promotes survival, focusing on protective effects of Cl-amidine on immune response. We confirmed survival-improving effect of Cl-amidine and are the first to explore the role of Cl-amidine in immune response. CLP caused bone marrow (BM) and thymus atrophy, decreased innate immune cells in BM. CLP increased levels of cytokines (IL-1β, IL-6, and TNF-α) and bacteria load in blood/liver. In primary splenocyte culture, lipopolysaccharide increased TNF-α production. In contrast, Cl-amidine attenuated these CLP and lipopolysaccharide-induced alterations. Moreover, Cl-amidine increased circulating monocytes. Collectively, our results demonstrate Cl-amidine plays protective roles by significantly decreasing BM and thymus atrophy, restoring innate immune cells in BM, increasing blood monocytes and blood/liver bacteria clearance, and attenuating pro-inflammatory cytokine production in a murine model of lethal sepsis. [ABSTRACT FROM AUTHOR]