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Host cystathionine-γ lyase derived hydrogen sulfide protects against Pseudomonas aeruginosa sepsis.

ABSTRACT: Hydrogen sulfide (H2S) has recently been recognized as a novel gaseous transmitter with several anti-inflammatory properties. The role of host- derived H2S in infections by Pseudomonas aeruginosa was investigated in clinical and mouse models. H2S concentrations and survival was assessed in septic patients with lung infection. Animal experiments using a model of severe systemic multidrug-resistant P. aeruginosa infection were performed using mice with a constitutive knock-out of cystathionine-γ lyase (Cse) gene (Cse-/-) and wild-type mice with a physiological expression (Cse+/+). Experiments were repeated in mice after a) treatment with cyclophosphamide; b) bone marrow transplantation (BMT) from a Cse+/+ donor; c) treatment with H2S synthesis inhibitor aminooxyacetic acid (ΑΟΑΑ) or propargylglycine (PAG) and d) H2S donor sodium thiosulfate (STS) or GYY3147. Bacterial loads and myeloperoxidase activity were measured in tissue samples. The expression of quorum sensing genes (QS) was determined in vivo and in vitro. Cytokine concentration was measured in serum and incubated splenocytes. Patients survivors at day 28 had significantly higher serum H2S compared to non-survivors. A cut- off point of 5.3 μΜ discriminated survivors with sensitivity 92.3%. Mortality after 28 days was 30.9% and 93.7% in patients with H2S higher and less than 5.3 μΜ (p = 7 x 10-6). In mice expression of Cse and application of STS afforded protection against infection with multidrug-resistant P. aeruginosa. Cyclophosphamide pretreatment eliminated the survival benefit of Cse+/+ mice, whereas BMT increased the survival of Cse-/- mice. Cse-/- mice had increased pathogen loads compared to Cse+/+ mice. Phagocytic activity of leukocytes from Cse-/- mice was reduced but was restored after H2S supplementation. An H2S dependent down- regulation of quorum sensing genes of P.aeruginosa could be demonstrated in vivo and in vitro. Endogenous H2S is a potential independent parameter correlating with the outcome of P. aeruginosa. H2S provides resistance to infection by MDR bacterial pathogens.

SUBMITTER: Renieris G

PROVIDER: S-EPMC8051778 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Traditionally, hydrogen sulfide (H2S) was simply considered as a toxic and foul smelling gas, but recently H2S been brought into the spot light of cardiovascular research and development. Since the 1990s, H2S has been mounting evidence of physiological properties such as immune modification, vascular relaxation, attenuation of oxidative stress, inflammatory mitigation, and angiogenesis. H2S has since been recognized as the third physiological gaseous signaling molecule, along with CO and NO [65,66]. H2S is produced endogenously through several key enzymes, including cystathionine β-lyase (CBE), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (MST)/cysteine aminotransferase (CAT). These specific enzymes are expressed accordingly in various organ systems and CSE is the predominant H2S-producing enzyme in the cardiovascular system. The cystathionine γ-lyase (CSE)/H2S pathway has demonstrated various cardioprotective effects, including anti-atherosclerosis, anti-hypertension, pro-angiogenesis, and attenuation of myocardial ischemia-reperfusion injury. CSE exhibits its anti-atherosclerotic effect through 3 mechanisms, namely reduction of chemotactic factor inter cellular adhesion molecule-1 (ICAM-1) and CX3CR1, inhibition of macrophage lipid uptake, and induction of smooth muscle cell apoptosis via MAPK pathway. The CSE/H2S pathway's anti-hypertensive properties are demonstrated via aortic vasodilation through several mechanisms, including the direct stimulation of KATP channels of vascular smooth muscle cells (VSMCs), induction of MAPK pathway, and reduction of homocysteine buildup. Also, CSE/H2S pathway plays an important role in angiogenesis, particularly in increased endothelial cell growth and migration, and in increased vascular network length. In myocardial ischemia-reperfusion injuries, CSE/H2S pathway has shown a clear cardioprotective effect by preserving mitochondria function, increasing antioxidant production, and decreasing infarction injury size. However, CSE/H2S pathway's role in inflammation mitigation is still clouded, due to both pro and anti-inflammatory results presented in the literature, depending on the concentration and form of H2S used in specific experiment models.

Project description:BackgroundHydrogen sulfide (H2S), produced by the activity of cystathionine-gamma-lyase (CSE), is a key mediator of inflammation in sepsis. The liver sinusoidal endothelial cells (LSECs) are important target and mediator of sepsis. The aim of this study was to investigate the role of CSE-derived H2S on inflammation and LSECs fenestrae in caecal-ligation and puncture (CLP)-induced sepsis using CSE KO mice.MethodsSepsis was induced by CLP, and mice (C57BL/6J, male) were sacrificed after 8 hours. Liver, lung, and blood were collected and processed to measure CSE expression, H2S synthesis, MPO activity, NF-?B p65, ERK1/2, and cytokines/chemokines levels. Diameter, frequency, porosity and gap area of the liver sieve were calculated from scanning electron micrographs of the LSECs.ResultsAn increased CSE expression and H2S synthesizing activity in the liver and lung of wild-type mice following CLP-induced sepsis. This was associated with an increased liver and lung MPO activity, and increased liver and lung and plasma levels of the pro-inflammatory cytokines TNF-?, IL-6, and IL-1?, and the chemokines MCP-1 and MIP-2?. Conversely, CSE KO mice had less liver and lung injury and reduced inflammation following CLP-induced sepsis as evidenced by decreased levels of H2S synthesizing activity, MPO activity, and pro-inflammatory cytokines/chemokines production. Extracellular-regulated kinase (ERK1/2) and nuclear factor-?B p65 (NF-?B) became significantly activated after the CLP in WT mice but not in CSE KO mice. In addition, CLP-induced damage to the LSECs, as indicated by increased defenestration and gaps formation in the LSECs compared to WT sham control. CSE KO mice showed decreased defenestration and gaps formation following sepsis.ConclusionsMice with CSE (an H2S synthesising enzyme) gene deletion are less susceptible to CLP-induced sepsis and associated inflammatory response through ERK1/2-NF-?B p65 pathway as evidenced by reduced inflammation, tissue damage, and LSECs defenestration and gaps formation.

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Host cystathionine-γ lyase derived hydrogen sulfide protects against Pseudomonas aeruginosa sepsis.

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