Agmatine protects against zymosan-induced acute lung injury in mice by inhibiting NF-κB-mediated inflammatory response

Biogenic Amine Content Analysis of Three Chicken-Based Dry Pet Food Formulations

The pet food market is constantly expanding, and more and more attention is paid to the feeding of pets. Dry foods stand out and are often preferred due to their long shelf life, ease of administration, and low cost. In this context, dry foods are formulated from fresh meats, meat meals, or a mix of the two. These raw materials are often meat not fit for human consumption; they might be subject to contamination and proliferation of microorganisms which, by degrading the organic component, can lead to the formation of undesirable by-products such as biogenic amines. These nitrogenous compounds obtained by decarboxylation of amino acids can therefore be found in high-protein foods, and their ingestion in large quantities can cause intoxication and be harmful. This study aims at analyzing the possible presence of biogenic amines in three different formulations of chicken-based kibbles for pets: one obtained from fresh meat, one from meat meal, and one from a mix of the two. This study is also focused on the presence of free amino acids as they represent the key substrate for decarboxylating enzymes. Mass spectrometry (Q-TOF LC/MS) was used to analyze the presence of biogenic amines and free amino acids. The results show that fresh-meat-based products have a lower content of biogenic amines, and at the same time a higher quantity of free amino acids; on the contrary, meat-meal- and mix-based products have a greater quantity of biogenic amines and a lower concentration of free amino acids, suggesting that there has been a higher microbial proliferation as proved by the total aerobic mesophilic bacteria counts. It is therefore clear that fresh-meat-based kibbles are to be preferred when they are used for preparing dry pet food due to the lowest concentration of biogenic amines.

Agmatine Mitigates Inflammation-Related Oxidative Stress in BV-2 Cells by Inducing a Pre-Adaptive Response

Neuroinflammation and microglial activation, common components of most neurodegenerative diseases, can be imitated in vitro by challenging microglia cells with Lps. We here aimed to evaluate the effects of agmatine pretreatment on Lps-induced oxidative stress in a mouse microglial BV-2 cell line. Our findings show that agmatine suppresses nitrosative and oxidative burst in Lps-stimulated microglia by reducing iNOS and XO activity and decreasing O₂^- levels, arresting lipid peroxidation, increasing total glutathione content, and preserving GR and CAT activity. In accordance with these results, agmatine suppresses inflammatory NF-kB, and stimulates antioxidant Nrf2 pathway, resulting in decreased TNF, IL-1 beta, and IL-6 release, and reduced iNOS and COX-2 levels. Together with increased ARG1, CD206 and HO-1 levels, our results imply that, in inflammatory conditions, agmatine pushes microglia towards an anti-inflammatory phenotype. Interestingly, we also discovered that agmatine alone increases lipid peroxidation end product levels, induces Nrf2 activation, increases total glutathione content, and GPx activity. Thus, we hypothesize that some of the effects of agmatine, observed in activated microglia, may be mediated by induced oxidative stress and adaptive response, prior to Lps stimulation.

Fucoxanthin, a Marine Xanthophyll Isolated From Conticribra weissflogii ND-8: Preventive Anti-Inflammatory Effect in a Mouse Model of Sepsis

Background: Fucoxanthin (FX), a xanthophyll pigment which occurs in marine brown algae with remarkable biological properties, has been proven to be safe for consumption by animals. Although FX has various pharmacological effects including anti-inflammatory, anti-tumor, anti-obesity, antioxidant, anti-diabetic, anti-malarial, and anti-lipid, in vivo protective effect against sepsis has not been reported. In this study, we aimed at evaluation the efficacy of the FX in a model of sepsis mouse. Methods: FX was successfully isolated from Conticribra weissflogii ND-8 for the first time. The FX was identified by thin-layer chromatography (TLC), high-performance liquid chromatography-mass spectrometry (HPLC-MS), and nuclear magnetic resonance (NMR). Animals were randomly divided into 9 groups, including Sham group (mouse received an intraperitoneal injection of normal saline 1.0 ml/kg), FX-treated (0.1-1.0 ml/kg), Lipopolysaccharide (LPS)-treated (20 mg/kg), FX+LPS-treated (0.1-10.0 mg/kg and 20 mg/kg, respectively), and urinastatin groups (10⁴ U/kg). Nuclear factor (NF)-κB activation could be potential treatment for sepsis. NF-κB signaling components were determined by western-blotting. IL-6, IL-1β, TNF-α production, and NF-κB activation were evaluated by ELISA and immunofluorescent staining in vitro. Results: FX was found to decrease the expression of inflammatory cytokines including IL-6, IL-1β, and TNF-α, in a prophylactic manner in the LPS-induced sepsis mouse model. Meanwhile, FX significantly inhibits phosphorylation of the NF-κB signaling pathway induced by LPS at the cellular level and reduces the nuclear translocation of NF-κB. The IC₅₀ for suppressing the expression of NF-κB was 11.08 ± 0.78 μM in the THP1-Lucia™ NF-κB cells. Furthermore, FX also inhibits the expression of inflammatory factors in a dose-dependent manner with the IC₅₀ inhibition of IL-6 production was 2.19 ± 0.70 μM in Raw267.4 macrophage cells. It is likely that the molecules with the ability of targeting NF-κB activation and inflammasome assembly, such as fucoxanthin, are interesting subjects to be used for treating sepsis.

Anti-inflammatory Property of Imperatorin on Alveolar Macrophages and Inflammatory Lung Injury

Imperatorin is one of the furanocoumarin derivatives and exists in many medicinal herbs with anticancer, antiviral, antibacterial, and antihypertensive activities. In this study, we examined the anti-inflammatory effects of imperatorin on inflammation-associated lung diseases. Imperatorin reduced iNOS and COX-2 expression and also IL-6 and TNFα production enhanced by zymosan. Imperatorin also inhibited the signaling pathways of JAK/STAT and NF-κB. Moreover, in vivo study also revealed that zymosan-induced immune cell infiltration, pulmonary fibrosis, and edema were relieved by imperatorin in mice. We found that imperatorin exerts anti-inflammatory effects that are associated with amelioration of lung inflammation, edema, and rapid fibrosis. Studies on alveolar macrophages also reveal that imperatorin reduced the production of pro-inflammatory mediators and cytokines and inhibited pro-inflammatory JAK1/STAT3 and NF-κB signaling pathways. These results indicate that imperatorin may be a potential anti-inflammatory agent for inflammatory-associated lung diseases.

Agmatine accumulation by Pseudomonas aeruginosa clinical isolates confers antibiotic tolerance and dampens host inflammation

PURPOSE

In the cystic fibrosis (CF) airways, Pseudomonas aeruginosa undergoes diverse physiological changes in response to inflammation, antibiotic pressure, oxidative stress and a dynamic bioavailable nutrient pool. These include loss-of-function mutations that result in reduced virulence, altered metabolism and other phenotypes that are thought to confer a selective advantage for long-term persistence. Recently, clinical isolates of P. aeruginosa that hyperproduce agmatine (decarboxylated arginine) were cultured from individuals with CF. Sputum concentrations of this metabolite were also shown to correlate with disease severity. This raised the question of whether agmatine accumulation might also confer a selective advantage for P. aeruginosa during chronic colonization of the lung.

METHODOLOGY AND RESULTS

We screened a library of P. aeruginosa CF clinical isolates and found that ~5 % of subjects harboured isolates with an agmatine hyperproducing phenotype. Agmatine accumulation was a direct result of mutations in aguA, encoding the arginine deiminase that catalyses the conversion of agmatine into various polyamines. We also found that agmatine hyperproducing isolates (aguA-) had increased tolerance to the cationic antibiotics gentamicin, tobramycin and colistin relative to their chromosomally complemented strains (aguA+). Finally, we revealed that agmatine diminishes IL-8 production by airway epithelial cells in response to bacterial infection, with a consequent decrease in neutrophil recruitment to the murine airways in an acute pneumonia model.

CONCLUSION

These data highlight a potential new role for bacterial-derived agmatine that may have important consequences for the long-term persistence of P. aeruginosa in the CF airways.

So-Cheong-Ryoung-Tang Attenuates Pulmonary Inflammation Induced by Cigarette Smoke in Bronchial Epithelial Cells and Experimental Mice

So-Cheong-Ryoung-Tang is a traditionally used herbal formula for the treatment of pulmonary diseases in China, Korea, and Japan. We investigated the protective effects of So-Cheong-Ryong-Tang water extract (SCWE) in cigarette smoke concentrate (CSC) stimulated human airway epithelial cell line NCI-H292 and mice exposed cigarette smoke (CS) and lipopolysaccharide (LPS). In the CSC-stimulated NCI-H292 cells, SCWE inhibited proinflammatory cytokines in a concentration-dependent manner, as evidenced by a reduction in their mRNA levels. Also, SCWE significant reduced inducible nitric oxide synthase (iNOS) expression and nuclear factor kappa B (NF-κB) phosphorylation in CSC-stimulated cells. The mice were exposed to CS for 1 h per day (a total of eight cigarettes per day) for 7 days and received LPS intranasally on day 5. The mice were administered a dose of SCWE (100 and 200 mg/kg) 1 h before CS exposure. In in vivo, SCWE decreased the inflammatory cell count and reduced the expression of the proinflammatory cytokines in the broncho-alveolar lavage fluid (BALF) compared with CS and LPS exposed mice. SCWE attenuated inflammatory cell infiltration in airway induced by CS and LPS exposure, and this decrease was accompanied by a reduction in the expression levels of iNOS and MMP-9 in lung tissue. The extract also inhibited the phosphorylation of inhibitor of kappa B alpha (IκBα) and NF-κB induced by CS and LPS exposure in lung tissue. These results suggest that SCWE may effectively inhibit airway inflammatory responses induced by CS and LPS exposure via the NF-κB pathway. Therefore, SCWE may be a potential treatment for airway inflammatory diseases, such as chronic obstructive pulmonary disease (COPD).

Neuroprotective effect of agmatine (decarboxylated l-arginine) against oxidative stress and neuroinflammation in rotenone model of Parkinson's disease

Parkinson's disease (PD) is the second most common age-related neurodegenerative disease after Alzheimer's disease, characterized by loss of dopaminergic neurons in substantia nigra pars compacta, accompanied by motor and nonmotor symptoms. The neuropathological hallmarks of PD are well reported, but the etiology of the disease is still undefined; several studies assume that oxidative stress, mitochondrial defects, and neuroinflammation play vital roles in the progress of the disease. The current study was established to investigate the neuroprotective effect of agmatine on a rotenone (ROT)-induced experimental model of PD. Adult male Sprague Dawley rats were subcutaneously injected with ROT at a dose of 2 mg/kg body weight for 35 days. Agmatine was injected intraperitoneally at 50 and 100 mg/kg body weight, 1 h prior to ROT administration. ROT-treated rats that received agmatine showed better performance on beam walking and an elevated number of rears within the cylinder test. In addition, agmatine reduced midbrain malondialdehyde as an indication of lipid peroxidation, pro-inflammatory cytokines including tumor necrosis factor alpha and interleukin-1β, and glial fibrillary acidic protein. Moreover, agmatine was responsible for preventing loss of tyrosine hydroxylase-positive neurons. In conclusion, our study showed that agmatine possesses a dose-dependent neuroprotective effect through its antioxidant and anti-inflammatory activities. These findings need further clinical investigations of agmatine as a promising neuroprotective agent for the future treatment of PD.

[Exogenous agmatine inhibits lipopolysaccharide-induced activation and dysfunction of human umbilical vein endothelial cells]

OBJECTIVE

To investigate whether exogenous agmatine inhibits lipopolysaccharide (LPS)-induced activation and dysfunction of human umbilical vein endothelial cells (HUVECs) by modulating nuclear factor-κB (NF-κB) and MAPK signal pathways and the production of reactive oxygen species (ROS).

METHODS

Cultured HUVECs were treated with agmatine at the optimized concentration of 1.0 mmolγL, LPS (10 µgγmL), and LPS + agmatine, with or without pretreatment with the inhibitors of NF-κB (PDTC), p38 (SB203580), and ERK (PD98059) for 1 h. The levels of soluble vascular cell adhesion molecule 1 (VCAM-1), soluble intercellular adhesion molecule 1 (sICAM-1), soluble E-selectin and monocyte chemoattractant protein 1 (MCP-1) in the supernatant were determined using ELISA, and their mRNA expressions, along with heme oxygenase-1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO-1), were assessed using real-time PCR. ROS production in the cells was determined using 2, 7-dichlorofluoresce in diacetate (DCFH-DA) as the fluorescence probe. The protein expressions of VCAM-1, ICAM-1, p65, phospho-p65 (p-p65), IκBα, p-IκBα, ERK, p-ERK, p38, p-p38, JNK, and p-JNK were detected using Western blotting.

RESULTS

LPS stimulation for 6 and 24 h significantly increased the levels of sVCAM-1, sICAM-1, sE-selectin and MCP-1 in the supernatant, intracellular ROS production, and the mRNA expressions of these molecules (P<0.05). Intervention with 1 mmolγL agmatine, similar with pretreatment with p38, ERK and NF-κB inhibitors, obviously inhibited such effects of LPS in HUVECs (P<0.05). Agmatine significantly up-regulated the mRNA expression of HO-1 (P<0.05), inhibited LPS-induced phosphorylation of p38, ERK, nuclear p65 and cytoplasmic IκBα, and up-regulated the protein expression of cytoplasmic IκBα.

CONCLUSION

Agmatine inhibits LPS-induced activation and dysfunction of HUVECs by modulating NF-κB and MAPK signal pathways to down-regulate the expressions of adhesion molecules and chemokines and by up-regulating the expression of HO-1 to reduce ROS production.

[Exogenous agmatine inhibits lipopolysaccharide-induced activation and dysfunction of human umbilical vein endothelial cells]

OBJECTIVE

To investigate whether exogenous agmatine inhibits lipopolysaccharide (LPS)-induced activation and dysfunction of human umbilical vein endothelial cells (HUVECs) by modulating nuclear factor-κB (NF-κB) and MAPK signal pathways and the production of reactive oxygen species (ROS).

METHODS

Cultured HUVECs were treated with agmatine at the optimized concentration of 1.0 mmolγL, LPS (10 µgγmL), and LPS + agmatine, with or without pretreatment with the inhibitors of NF-κB (PDTC), p38 (SB203580), and ERK (PD98059) for 1 h. The levels of soluble vascular cell adhesion molecule 1 (VCAM-1), soluble intercellular adhesion molecule 1 (sICAM-1), soluble E-selectin and monocyte chemoattractant protein 1 (MCP-1) in the supernatant were determined using ELISA, and their mRNA expressions, along with heme oxygenase-1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO-1), were assessed using real-time PCR. ROS production in the cells was determined using 2, 7-dichlorofluoresce in diacetate (DCFH-DA) as the fluorescence probe. The protein expressions of VCAM-1, ICAM-1, p65, phospho-p65 (p-p65), IκBα, p-IκBα, ERK, p-ERK, p38, p-p38, JNK, and p-JNK were detected using Western blotting.

RESULTS

LPS stimulation for 6 and 24 h significantly increased the levels of sVCAM-1, sICAM-1, sE-selectin and MCP-1 in the supernatant, intracellular ROS production, and the mRNA expressions of these molecules (P<0.05). Intervention with 1 mmolγL agmatine, similar with pretreatment with p38, ERK and NF-κB inhibitors, obviously inhibited such effects of LPS in HUVECs (P<0.05). Agmatine significantly up-regulated the mRNA expression of HO-1 (P<0.05), inhibited LPS-induced phosphorylation of p38, ERK, nuclear p65 and cytoplasmic IκBα, and up-regulated the protein expression of cytoplasmic IκBα.

CONCLUSION

Agmatine inhibits LPS-induced activation and dysfunction of HUVECs by modulating NF-κB and MAPK signal pathways to down-regulate the expressions of adhesion molecules and chemokines and by up-regulating the expression of HO-1 to reduce ROS production.

MicroRNA‑146a/Toll‑like receptor 4 signaling protects against severe burn‑induced remote acute lung injury in rats via anti‑inflammation

The present study investigated the preventive effects of microRNA (miR)‑146a against severe burn‑induced remote acute lung injury (ALI) in rats and the underlying mechanism. The surface area of the skin was immersed in 100˚C water for 5‑10 sec on the dorsal surface. The expression level of miR‑146a was significantly downregulated in rats with burn‑induced ALI. Downregulation of miR‑146a increased inflammation, and inducible nitric oxide synthase (iNOS) and cyclooxygenase‑2 (COX‑2) expression in a model of ALI in vitro via the promotion of the Toll‑like receptor (TLR)4/nuclear factor (NF)‑κB signaling pathway. In addition, the overexpression of miR‑146a reduced inflammation, and iNOS and COX‑2 protein expression in the model of ALI in vitro via the suppression of the TLR4/NF‑κB signaling pathway. A TLR4 inhibitor reduced the function of anti‑miR‑146a on inflammation in the model of ALI. Collectively, the results of the present study demonstrated the preventive effects of miR‑146a against severe burn‑induced remote ALI in rats through the anti‑inflammatory‑regulated TLR4/NF‑κB signaling pathway.

Paracoccidioides brasiliensis presents metabolic reprogramming and secretes a serine proteinase during murine infection

Paracoccidoides brasiliensis and Paracoccidioides lutzii, the etiologic agents of paracoccidioidomycosis, cause disease in healthy and immunocompromised persons in Latin America. We developed a method for harvesting P. brasiliensis yeast cells from infected murine lung to facilitate in vivo transcriptional and proteomic profiling. P. brasiliensis harvested at 6 h post-infection were analyzed using RNAseq and LC-MS^E. In vivo yeast cells had 594 differentially expressed transcripts and 350 differentially expressed proteins. Integration of transcriptional and proteomic data indicated that early in infection (6 h), P. brasiliensis yeast cells underwent a shift in metabolism from glycolysis to β-oxidation, upregulated detoxifying enzymes to defend against oxidative stress, and repressed cell wall biosynthesis. Bioinformatics and functional analyses also demonstrated that a serine proteinase was upregulated and secreted in vivo. To our knowledge this is the first study depicting transcriptional and proteomic data of P. brasiliensis yeast cells upon 6 h post-infection of mouse lung.

Agmatine Reduces Lipopolysaccharide-Mediated Oxidant Response via Activating PI3K/Akt Pathway and Up-Regulating Nrf2 and HO-1 Expression in Macrophages

Macrophages are key responders of inflammation and are closely related with oxidative stress. Activated macrophages can enhance oxygen depletion, which causes an overproduction of reactive oxygen species (ROS) and leads to further excessive inflammatory response and tissue damage. Agmatine, an endogenous metabolite of L-arginine, has recently been shown to have neuroprotective effects based on its antioxidant properties. However, the antioxidant effects of agmatine in peripheral tissues and cells, especially macrophages, remain unclear. In this study we explored the role of agmatine in mediating antioxidant effects in RAW 264.7 cells and studied its antioxidant mechanism. Our data demonstrate that agmatine is an activator of Nrf2 signaling that markedly enhances Nrf2 nuclear translocation, increases nuclear Nrf2 protein level, up-regulates the expression of the Nrf2 downstream effector HO-1, and attenuates ROS generation induced by Lipopolysaccharide (LPS). We further demonstrated that the agmatine-induced activation of Nrf2 is likely through the PI3K/Akt pathway. LY294002, a specific PI3K/Akt inhibitor, abolished agmatine-induced HO-1 up-regulation and ROS suppression significantly. Inhibiting HO-1 pathway significantly attenuated the antioxidant effect of agmatine which the products of HO-1 enzymatic activity contributed to. Furthermore, the common membrane receptors of agmatine were evaluated, revealing that α2-adrenoceptor, I1-imidazoline receptor or I2-imidazoline receptor are not required by the antioxidant properties of agmatine. Taken together, our findings revealed that agmatine has antioxidant activity against LPS-induced ROS accumulation in RAW 264.7 cells involving HO-1 expression induced by Nrf2 via PI3K/Akt pathway activation.