Levels Of Arginase Research Articles

Lactiplantibacillus plantarum Reduced Renal Calcium Oxalate Stones by Regulating Arginine Metabolism in Gut Microbiota.

Renal calcium oxalate (CaOx) stones are a common kidney disease. There are few methods for reducing the formation of these stones. However, the potential of probiotics for reducing renal stones has received increasing interest. We previously isolated a strain of Lactiplantibacillus plantarum N-1 from traditional cheese in China. This study aimed to investigate the effects of N-1 on renal CaOx crystal deposition. Thirty rats were randomly allocated to three groups: control group (ddH2O by gavage), model group [ddH2O by gavage and 1% ethylene glycol (EG) in drinking water], and Lactiplantibacillus group (N-1 by gavage and 1% EG in drinking water). After 4 weeks, compared with the model group, the group treated with N-1 exhibited significantly reduced renal crystals (P < 0.05). In the ileum and caecum, the relative abundances of Lactobacillus and Eubacterium ventriosum were higher in the control group, and those of Ruminococcaceae UCG 007 and Rikenellaceae RC9 were higher in the N-1-supplemented group. In contrast, the relative abundances of Staphylococcus, Corynebacterium 1, Jeotgalicoccus, Psychrobacter, and Aerococcus were higher in the model group. We also predicted that the arginase level would be higher in the ileal microbiota of the model group than in the N-1-supplemented group with PICRUSt2. The arginase activity was higher, while the level of arginine was lower in the ileal contents of the model group than in the N-1-supplemented group. The arginine level in the blood was also higher in the N-1-supplemented group than in the model group. In vitro studies showed that exposure to arginine could reduce CaOx crystal adhesion to renal epithelial HK-2 cells. Our findings highlighted the important role of N-1 in reducing renal CaOx crystals by regulating arginine metabolism in the gut microbiota. Probiotics containing L. plantarum N-1 may be potential therapies for preventing renal CaOx stones.

Study on the serum arginase and nitrate levels in association with Fev1/Fvc ratio in chronic obstructive pulmonary disease

COPD is generally associated with chronic inflammation in peripheral airway and lung parenchyma which finally leads to obstruction of the airways. The diagnostic criteria for COPD is FEV1/FVC ratio which is less than 0.7. Arginase being the key enzyme of urea cycle, is also expressed in extra hepatic tissue including lung in the bronchial epithelial cells and endothelial cells. The main function of arginase here, is to regulate the formation of nitric oxide, indirectly competing for the common substrate L- arginine. The NO forms peroxynitrite on reaction with reactive oxygen species due to oxidative stress. Peoxynitrite is unstable molecule and breaks down to nitrite and nitrate. The present research work was approved by Institutional Ethical committee. Informed consent was obtained from the patients and controls prior to the study. It is a case control study and it included 45 COPD patients between the age group of 40-60 years who attended the outpatient department of pulmonary medicine, Maharajah’s Institute of Medical Sciences, Nellimarla, Vizianagaram. These are labeled cases. 45 normal healthy age and sex matched individuals with normal FEV1/FVC ratio are considered as controls.

High dietary lipid level decreases the immunity and disease resistance of abalone Haliotis discus hannai and affects the perilipin‐2/TLR4, JNK and Keap1/Nrf2 pathways

A 100-day feeding trial was conducted to investigate the influences of dietary lipid levels on the immunity and mechanism in abalone Haliotis discus hannai Ino. Abalones (initial weight: 10.98 ± 0.05 g) were fed with graded levels of dietary lipid, which were 15.73, 23.41, 31.72, 38.25, 46.35, 55.63, 61.70 and 67.19 g/kg. Results showed that compared with the treatment with 38.25 g/kg of dietary lipid, 67.19 g/kg of dietary lipid increased the cumulative mortality of abalone after a challenge with Vibrio parahaemolyticus. Meanwhile, 67.19 g/kg of dietary lipid decreased the activities of lysozyme (LZ) and acid phosphatase (ACP) in serum, and the mRNA levels of β-defensin and mytimacin 6 in hepatopancreas of abalone. The mRNA levels of tumour necrosis factor α (tnfα), activator protein 1 (ap-1), nuclear factor κB (nf-κb), interleukin 1 receptor-associated kinase-4 (irak4), myeloid differentiation primary response protein MyD88 (myd88), toll-like receptor 2 (tlr2), tlr4 and perilipin-2, and the protein level of interleukin-1β (IL-1β), TNFα, NF-κBp65, AP-1, MyD88 and Perilipin-2 in hepatopancreas were up-regulated by 67.19 g/kg of dietary lipid. However, the mRNA levels of arginase and inhibitor of κBα (iκbα) were down-regulated. Besides, 67.19 g/kg of dietary lipid up-regulated the mRNA levels of executor apoptosis-related cysteine peptidase 3 (caspase-3), caspase-7 and B-cell lymphoma protein-2-associated X protein (bax), and the protein levels of caspase-3 and c-Jun N-terminal kinases (JNK) in hepatopancreas. Moreover, high dietary lipid level down-regulated the mRNA levels of copper/zinc superoxide dismutase (cuznsod), manganese superoxide dismutase (mnsod), catalase (cat), glutathione peroxidase (gpx), glutathione-S-transferase (gst) and NF-E2-related factor 2 (nrf2), while up-regulated the mRNA and protein levels of Kelch-like ECH-associated protein 1 (Keap1) in hepatopancreas. It was concluded that a high level (67.19 g/kg) of dietary lipid decreased the immunity of abalone, which might be related to the aggravated inflammation and apoptosis, and decreased anti-oxidative capacity under Perilipin-2/TLRs/MyD88/IRAK4/(NF-κB or AP-1), JNK/Bcl-2/Bax and Keap1/Nrf2 signalling.

CCL2 produced by pancreatic ductal adenocarcinoma is essential for the accumulation and activation of monocytic myeloid-derived suppressor cells.

IntroductionThe development of pancreatic ductal adenocarcinoma (PDAC) is closely tied with the immune system. C‐C motif chemokine ligands (CCL) were proved to lead to immune recruitment and training. Thus, we reckoned CCL2 to be the kernel of immune suppression in PDAC tissues.MethodsWe compared normal pancreatic tissues with PDAC tissues according to The Cancer Genome Atlas (TCGA) and clinical samples. Flow cytometry was used to identify M‐MDSCs. We further demonstrated immune suppression of M‐MDSCs according to proliferation rates of CD8+ T cells/CD4+ T cells. Levels of reactive oxygen species (ROS) and Arginase were also tested by flow cytometry, enzyme‐linked immunosorbent assay, and western blot analysis. We also analyzed the specific mechanisms by cluster analysis after CCL2 stimulating M‐MDSCs.ResultsWe found that CCL2 highly increased in PDAC tissues. CCL2 is positively related to CD33 and CD14, markers of monocytic myeloid‐derived suppressor cells (M‐MDSCs). We have demonstrated that CCL2 recruited M‐MDSCs into PDAC tissues both in vitro and in vivo. M‐MDSCs recruitment is accompanied by sustained immune suppression. Furthermore, we have found that M‐MDSCs impeded T cell proliferation and produced high levels of ROS and Arginase, which can be enhanced by CCL2. Mechanistically, CCL2 stimulated M‐MDSCs led to a significant upregulation of genes, a large part of which accumulated in the mitogen‐activated protein kinase signaling pathway. Treatment of aloesin, MAPK signaling inhibitor, relieved the associated immunosuppressive phenotype induced by CCL2.ConclusionsOur study indicates that PDAC cells produced CCL2, which promoted localized M‐MDSC recruitment and immune suppression, thereby promoting tumor progression.

Gut Microbiota Disorders Promote Inflammation and Aggravate Spinal Cord Injury Through the TLR4/MyD88 Signaling Pathway.

Background: In spinal cord injury (SCI), systemic inflammation and the death of nerve cells in the spinal cord are life threatening. The connection between gut microbiota and signaling pathways has been a hot research topic in recent years. The Toll-like receptor 4/Myeloid differentiation factor 88 (TLR4/MyD88) signaling pathway is closely related to the inflammatory response. This study explored whether the gut microbiota imbalance could affect the TLR4/MyD88 signaling pathway to regulate SCI to provide a new basis for SCI research and treatment.Methods: An SCI model was constructed to study the influence on the injury of gut microbiota. 16S amplicon sequencing was used to identify the diversity and abundance of gut microbes. Fecal microbiota transplantation was performed in mice with SCI. ELISA was used to detect the serum levels of pro-inflammatory and anti-inflammatory factors in mice. Hematoxylin and eosin staining was used to observe SCI in mice. Immunofluorescence was used to detect the rates of loss glial fibrillary acidic protein (GFAP), neuronal nuclear protein (NeuN), and ionized calcium-binding adapter molecule 1 (IBA1) in the spinal cord as indicators of apoptosis. The expression of the TLR4/MyD88 signaling pathway was detected by qRT-PCR and western blotting.Results: Significant differences were observed in the gut microbiota of SCI mice and normal mice. The gut microbiota of SCI mice was imbalanced. The levels of pro-inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 in SCI mice were increased, as was the level of the toxic induced nitric oxide synthase. The levels of anti-inflammatory factors IL-4, transforming growth factor-β, and IL-10 were decreased, as was the level of arginase-1. The apoptosis rates of GFAP, NeuN, and IBA1 were increased. The TLR4/MyD88 signaling pathway was activated. In the SCI group, inflammation increased after fecal transplantation, apoptosis of GFAP, NeuN, and IBA1 increased, and SCI was more serious.Conclusion: The TLR4/MyD88 signaling pathway promotes the death of nerve cells by inducing inflammation. Gut microbiota dysregulation can lead to aggravated SCI by activating the TLR4/MyD88 signaling pathway.

Dysregulated Microglial Cell Activation and Proliferation Following Repeated Antigen Stimulation.

Upon reactivation of quiescent neurotropic viruses antigen (Ag)-specific brain resident-memory CD8+ T-cells (bTRM) may respond to de novo-produced viral Ag through the rapid release of IFN-γ, which drives subsequent interferon-stimulated gene expression in surrounding microglia. Through this mechanism, a small number of adaptive bTRM may amplify responses to viral reactivation leading to an organ-wide innate protective state. Over time, this brain-wide innate immune activation likely has cumulative neurotoxic and neurocognitive consequences. We have previously shown that HIV-1 p24 Ag-specific bTRM persist within the murine brain using a heterologous prime-CNS boost strategy. In response to Ag restimulation, these bTRM display rapid and robust recall responses, which subsequently activate glial cells. In this study, we hypothesized that repeated challenges to viral antigen (Ag) (modeling repeated episodes of viral reactivation) culminate in prolonged reactive gliosis and exacerbated neurotoxicity. To address this question, mice were first immunized with adenovirus vectors expressing the HIV p24 capsid protein, followed by a CNS-boost using Pr55Gag/Env virus-like particles (HIV-VLPs). Following the establishment of the bTRM population [>30 days (d)], prime-CNS boost animals were then subjected to in vivo challenge, as well as re-challenge (at 14 d post-challenge), using the immunodominant HIV-1 AI9 CD8+ T-cell epitope peptide. In these studies, Ag re-challenge resulted in prolonged expression of microglial activation markers and an increased proliferative response, longer than the challenge group. This continued expression of MHCII and PD-L1 (activation markers), as well as Ki67 (proliferative marker), was observed at 7, 14, and 30 days post-AI9 re-challenge. Additionally, in vivo re-challenge resulted in continued production of inducible nitric oxide synthase (iNOS) with elevated levels observed at 7, 14 and 30 days post re-challenge. Interestingly, iNOS expression was significantly lower among challenged animals when compared to re-challenged groups. Furthermore, in vivo specific Ag re-challenge produced lower levels of arginase (Arg)-1 when compared with the challenged group. Taken together, these results indicate that repeated Ag-specific stimulation of adaptive immune responses leads to cumulative dysregulated microglial cell activation.

Positive effects of roflumilast on behavior, neuroinflammation, and white matter injury in mice with global cerebral ischemia.

Inhibition of phosphodiesterase 4 (PDE4) is a promising pharmacological strategy for the treatment of cerebral ischemic conditions. To increase the relevance and increase the translational value of preclinical studies, it is important to conduct experiments using different animal species and strains, different animal models, and to evaluate long-term functional outcomes after cerebral ischemia. In the present study, the effects of the selective PDE4 inhibitor roflumilast were evaluated in vivo and in vitro. Balb/c mice were subjected to bilateral common carotid artery occlusion (BCCAO) and tested during 21 days in multiple behavioral tasks to investigate the long-term effects of roflumilast on functional recovery. The effects of roflumilast were also investigated on hippocampal cell loss, white matter injury, and expression of neuroinflammatory markers. Roflumilast prevented cognitive and emotional deficits induced by BCCAO in mice. Roflumilast also prevented neurodegeneration and reduced the white matter damage in the brain of ischemic animals. Besides, roflumilast decreased Iba-1 (microglia marker) levels and increased Arginase-1 (Arg-1; microglia M2 phenotype marker) levels in the hippocampus of these mice. Likewise, roflumilast suppressed inducible nitric oxide synthase (microglia M1 phenotype marker) expression and increased Arg-1 levels in a primary mouse microglia culture. These findings support evidence that PDE4 inhibition by roflumilast might be beneficial in cerebral ischemic conditions. The neuroprotective effects of roflumilast appear to be mediated by a decrease in neuroinflammation.

Severe COVID-19 Is Characterized by an Impaired Type I Interferon Response and Elevated Levels of Arginase Producing Granulocytic Myeloid Derived Suppressor Cells.

COVID-19 ranges from asymptomatic in 35% of cases to severe in 20% of patients. Differences in the type and degree of inflammation appear to determine the severity of the disease. Recent reports show an increase in circulating monocytic-myeloid-derived suppressor cells (M-MDSC) in severe COVID 19 that deplete arginine but are not associated with respiratory complications. Our data shows that differences in the type, function and transcriptome of granulocytic-MDSC (G-MDSC) may in part explain the severity COVID-19, in particular the association with pulmonary complications. Large infiltrates by Arginase 1+ G-MDSC (Arg+G-MDSC), expressing NOX-1 and NOX-2 (important for production of reactive oxygen species) were found in the lungs of patients who died from COVID-19 complications. Increased circulating Arg+G-MDSC depleted arginine, which impaired T cell receptor and endothelial cell function. Transcriptomic signatures of G-MDSC from patients with different stages of COVID-19, revealed that asymptomatic patients had increased expression of pathways and genes associated with type I interferon (IFN), while patients with severe COVID-19 had increased expression of genes associated with arginase production, and granulocyte degranulation and function. These results suggest that asymptomatic patients develop a protective type I IFN response, while patients with severe COVID-19 have an increased inflammatory response that depletes arginine, impairs T cell and endothelial cell function, and causes extensive pulmonary damage. Therefore, inhibition of arginase-1 and/or replenishment of arginine may be important in preventing/treating severe COVID-19.

INFLUENCE OF NITRIC OXIDE, HYDROGEN SULFIDE, MARKERS OF ANTIOXIDANT HOMEOSTASIS AND BONE METABOLISM OF ORAL FLUID ON THE DENTAL HEALTH OF CHILDREN WITH MILD IODINE DEFICIENCY, LATENT IRON DEFICIENCY AND ASSOCIATED MICROELEMENTOSIS

The article analyzes the metabolism of nitric oxide (NO), hydrogen sulfide (H2S), markers of antioxidant protection, bone metabolism of oral fluid and features of dental status in children with mild iodine deficiency (МІD), latent iron deficiency and combined (LID); a combination of trace elements was examined.&#x0D; As a result of the study (age group from 6 to 11 years) under the conditions of МІD in boys there was an increase in the level of NO2, NO2- + NO3-, and in girls - peroxynitrite in the oral fluid. In schoolchildren with LІD changes in the studied parameters were less pronounced (in the oral fluid increased NO2 concentration regardless of gender and increased peroxynitrite content only in girls). Under conditions of combined micronutrient imbalance in the oral fluid levels of NO2 increased, the amount of NO2- and NO3-, peroxynitrite, regardless of gender, and girls, in addition, levels of arginase decreased. Such changes were observed against the background of weakening of antioxidant protection of oral fluid. In particular, acid phosphatase (АсР) was activated under the conditions of LD in boys against the background of alkaline phosphatase (АР) inhibition and reduction of total calcium levels in oral fluid. The same tendency was observed in girls of this group, in addition, they found inhibition of superoxide dismutase (SOD) activity of oral fluid. Under the conditions of LІD, regardless of gender, KF activation was observed against the background of АсР suppression (in boys), decrease in SOD activity (in girls). The most pronounced changes were observed in the oral fluid of children with combined iodine and iron deficiency: increased activity of АР regardless of gender, glutathione peroxidase (GP), LF in girls, inhibition of АсР activity in boys, decreased total calcium regardless of gender. The level of ionized calcium in the oral fluid increased only in girls.&#x0D; In children aged 12 to 18 years under the conditions of МІD, an increase in the concentration of peroxynitrite in the oral fluid regardless of gender and a decrease in arginase levels were found only in girls. In the oral fluid of boys with LІD found a decrease in L-arginine, in girls - and an increase in L-arginine, NO2 concentration on the background of a decrease in arginase and peroxynitrite. In high school students with combined microelements, regardless of gender, the content of peroxynitrite in the oral fluid and a decrease in the level of L-arginine in boys and an increase in arginase in girls. In this group, a significant increase in the concentration of H2S in schoolgirls, which can perform a protective function in oxidative stress or impaired blood supply, attracts attention. The results of the level of total, ionized calcium and phosphatase activity indicate an increase in the resorptive process in periodontal tissues in all experimental groups.&#x0D; During the dental examination, a high level of caries prevalence, a decrease in the level of hygiene, and a higher PMA index were found in older schoolchildren with a combination of microelements. The poorer level of dental health among boys concerning girls attracts attention, which can be explained by the better level of care and daily rehabilitation of the oral cavity in girls.&#x0D; Thus, under the conditions of preclinical microelements the indicators of NO metabolism change, the antioxidant reserve of oral fluid decreases, and markers of bone metabolism are disturbed. Such biochemical changes in the composition of oral fluid are compared with indicators of dental status.

Arginase, a Possible Therapeutic Target in Prostate Cancer

With increasing populations, the prevalence of prostate cancer increases. In the future, a significant public health crisis can be recognized in the present incidence of prostate cancer. In order to counter this, markers should be established for the advanced diagnosis and treatment of the illness prognosis. The cells dominate our immune system and grow into a detectable tumour, causing cancer. At this stage in the body, several processes are dominated, governed and deregulated by the tumour. In most cases, immune response undertakes measures by limiting the availability of Arginine. In this context it is fascinating to examine how the levels of Arginine fluctuate with the severity of the disease and the levels of Arginase and NO. Substances and methods: In 25 beginning phases and 25 advanced stage of the prostate cancer patients and compared to 25 healthy controls, 5 ml of the blood were taken and tested for serum levels of Arginina, and nitric oxide. A substantial reduction in arginine (p&lt;0.001) found was detected. In Arginase and levels a substantial increase (p&lt;0.001) was detected. Conclusion: Increased Arginase levels are linked to the illness progression and the result lowers as Arginase uses most phases. Therefore, Arginase inhibition can be promising therapeutic target in prostate cancer.

Immunosuppressive effects and mechanisms of three myeloid-derived suppressor cells subsets including monocytic-myeloid-derived suppressor cells, granulocytic-myeloid-derived suppressor cells, and immature-myeloid-derived suppressor cells.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immune cells of myeloid lineage. Recent reports have suggested that human MDSC are divided into three subsets: monocytic MDSC (M-MDSC), granulocytic MDSC (G-MDSC), and immature MDSC (I-MDSC). However, the characteristics of each human MDSC subset still remain unclear. To evaluate the immunosuppressive effects and mechanisms, we first performed a T-cell suppression assay using cells obtained from healthy donor peripheral blood samples. The levels of immune inhibitory molecules in the culture supernatant of each MDSC subset were measured to reveal the T-cell suppressive mechanisms. Then, we compared these results with the results from cells obtained from cancer patient blood samples. Finally, we investigated the difference in the frequency of each MDSC subset between the healthy donors and the cancer patients. Although M-MDSC and G-MDSC suppressed T-cell activation, I-MDSC had no T-cell suppressive effect. We found that the culture supernatant of M-MDSC and G-MDSC contained high levels of interleukin-1 receptor antagonist (IL-1RA) and arginase, respectively, in both healthy donors and cancer patients. No inhibitory molecules were detected in the culture supernatant of I-MDSC. The population of functional MDSC (M-MDSC and G-MDSC) in the total MDSC was significantly increased in cancer patients compared with that in healthy donors. Although M-MDSC and G-MDSC, which released IL-1RA and arginase, respectively, suppressed T-cell activation, I-MDSC did not have an immunosuppressive effect. The population of functional MDSC was increased in cancer patients compared with that in healthy donors.

Abstract 297: Innovation in delivering synthetically challenging bicyclic arginase inhibitors to enhance immunotherapy

Abstract Arginase overexpression has been associated with poor survival rates in advanced cancer patients treated with Keytruda. High levels of Arginase may lead to a depletion of arginine within the tumor microenvironment, inhibiting the immune response. Thus, arginase inhibition has the potential to greatly enhance immunotherapy treatment. Discovering novel arginase inhibitors was met with several challenges including analyzing/purifying extremely polar chemical matter without chromophores, synthetically challenging space, and poor bioavailability of compounds with ClogP less than minus two. Cross-functional collaborations and innovations rapidly overcame these challenges. Structural chemistry and modeling guided the design of novel arginase inhibitors. Analytical and purification groups developed innovative analytical/purification methods. Novel technologies including ReatIR and Vapourtec flow system, provided key intermediates to enable chartering into synthetically challenging space. Through creative cyclization strategies and active transport strategy to improve bioavailability, the team ultimately delivered a diverse set of potent and extremely synthetically challenging arginase inhibitors to study the potential of arginase inhibition. Preliminary in vivo evaluation showed single agent efficacy in an EMT6 model. These arginase inhibitors have the potential to enhance immunotherapy. Citation Format: Derun Li, Hongjun Zhang, Thomas W. Lyons, Theodore A. Martinot, Abdelghani Achab, Min lu, Lisa M. Nogle, Spencer McMinn, Matthew J. Mitcheltree, Matthew Childers, Qinglin Pu, Symon Gathiaka, Anand Palani, Kalyan Chakravarthy, Amy D. DeCastro, Jennifer O'Neil, Roshi Afshar, Nicole C. Walsh, Peter W. Fan, Mangeng Cheng, Richard Miller, Amy Doty, Rachel Palte, Hai-Young Kim, Josep Saurí, Adam Beard, Christopher Brynczka, Christian Fischer. Innovation in delivering synthetically challenging bicyclic arginase inhibitors to enhance immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 297.

Residual biomass from surfactin production is a source of arginase and adsorbed surfactin that is useful for environmental remediation.

Lipopeptides are important secondary metabolites produced by microbes. They find applications in environmental decontamination and in the chemical, pharmaceutical and food industries. However, their production is expensive. In the present work we propose three strategies to lower the production costs of surfactin. First, the coproduction of surfactin and arginase in a single growth. Second, extract the fraction of surfactin that adsorbs to the biomass and is removed from the growth medium through centrifugation. Third, use microbial biomass for the remediation of organic and inorganic contaminants. The coproduction of surfactin and arginase was evaluated by factorial design experiments using the LB medium supplemented with arginine. The best conditions for surfactin production were 22h of growth at 37°C using LB supplemented with arginine 7.3g/L. Almost similar conditions were found to produce highest levels of arginase, 24h and 6.45g/L arginine. Decontamination of phenol and copper from artificial samples was attained by treatment with residues from lipopeptide production. Thus, cell suspensions and wash-waters used to extract surfactin from the biomass. Cell suspensions were used to successfully remove hydroquinone. Cell suspensions and wash-waters containing surfactin were successfully used to recover copper from solution. Specific monitoring methods were used for phenol and metal solutions, respectively a biosensor based on tyrosinase and either atomic absorption flame ionization spectrometry or absorbance coupled to the Arduino™ platform. Therefore, we report three alternative strategies to lower the production costs in lipopeptide production, which include the effective recovery of copper and phenol from contaminated waters using residues from surfactin production. Sustainable and profitable production of surfactin can be achieved by a coproduction strategy of lipopeptides and enzymes. Lipopeptides are collected in the supernatant and enzymes in the biomass. In addition, lipopeptides that coprecipitate with biomass can be recovered by washing. Lipopeptide wash-waters find applications in remediation and cells can also be used for environmental decontamination.

IL-23 reshapes kidney resident cell metabolism and promotes local kidney inflammation.

Interstitial kidney inflammation is present in various nephritides in which serum interleukin 23 (IL-23) is elevated. Here we showed that murine and human renal tubular epithelial cells (TECs) expressing the IL-23 receptor (IL-23R) responded to IL-23 by inducing intracellular calcium flux, enhancing glycolysis, and upregulating calcium/calmodulin kinase IV (CaMK4), which resulted in suppression of the expression of the arginine-degrading enzyme arginase 1 (ARG1), thus increasing in situ levels of free L-arginine. Limited availability of arginine suppressed the ability of infiltrating T cells to proliferate and produce inflammatory cytokines. TECs from humans and mice with nephritis expressed increased levels of IL-23R and CaMK4 but reduced levels of ARG1. TEC-specific deletion of Il23r or Camk4 suppressed inflammation, whereas deletion of Arg1 exacerbated inflammation in different murine disease models. Finally, TEC-specific delivery of a CaMK4 inhibitor specifically curbed renal inflammation in lupus-prone mice without affecting systemic inflammation. Our data offer the first evidence to our knowledge of the immunosuppressive capacity of TECs through a mechanism that involves competitive uptake of arginine and signify the importance of modulation of an inflammatory cytokine in the function of nonlymphoid cells, which leads to the establishment of an inflammatory microenvironment. New approaches to treat kidney inflammation should consider restoring the immunosuppressive capacity of TECs.

Mesenchymal Stromal Cells From Emphysematous Donors and Their Extracellular Vesicles Are Unable to Reverse Cardiorespiratory Dysfunction in Experimental Severe Emphysema.

Although bone marrow-derived mesenchymal stromal cells (BM-MSCs) from patients with chronic obstructive pulmonary disease (COPD) appear to be phenotypically and functionally similar to BM-MSCs from healthy sources in vitro, the impact of COPD on MSC metabolism and mitochondrial function has not been evaluated. In this study, we aimed to comparatively characterize MSCs from healthy and emphysematous donors (H-MSCs and E-MSCs) in vitro and to assess the therapeutic potential of these MSCs and their extracellular vesicles (H-EVs and E-EVs) in an in vivo model of severe emphysema. For this purpose, C57BL/6 mice received intratracheal porcine pancreatic elastase once weekly for 4 weeks to induce emphysema; control animals received saline under the same protocol. Twenty-four hours after the last instillation, animals received saline, H-MSCs, E-MSCs, H-EVs, or E-EVs intravenously. In vitro characterization demonstrated that E-MSCs present downregulation of anti-inflammatory (TSG-6, VEGF, TGF-β, and HGF) and anti-oxidant (CAT, SOD, Nrf2, and GSH) genes, and their EVs had larger median diameter and lower average concentration. Compared with H-MSC, E-MSC mitochondria also exhibited a higher respiration rate, were morphologically elongated, expressed less dynamin-related protein-1, and produced more superoxide. When co-cultured with alveolar macrophages, both H-MSCs and E-MSCs induced an increase in iNOS and arginase-1 levels, but only H-MSCs and their EVs were able to enhance IL-10 levels. In vivo, emphysematous mice treated with E-MSCs or E-EVs demonstrated no amelioration in cardiorespiratory dysfunction. On the other hand, H-EVs, but not H-MSCs, were able to reduce the neutrophil count, the mean linear intercept, and IL-1β and TGF-β levels in lung tissue, as well as reduce pulmonary arterial hypertension and increase the right ventricular area in a murine model of elastase-induced severe emphysema. In conclusion, E-MSCs and E-EVs were unable to reverse cardiorespiratory dysfunction, whereas H-EVs administration was associated with a reduction in cardiovascular and respiratory damage in experimental severe emphysema.

Inhibition of KCa3.1 Channels Suppresses Atrial Fibrillation via the Attenuation of Macrophage Pro-inflammatory Polarization in a Canine Model With Prolonged Rapid Atrial Pacing.

Aims: To investigate the role of KCa3. 1 inhibition in macrophage pro-inflammatory polarization and vulnerability to atrial fibrillation (AF) in a canine model with prolonged rapid atrial pacing.Materials and Methods: Twenty beagle dogs (weighing 8–10 kg) were randomly assigned to a sham group (n = 6), pacing group (n = 7) and pacing+TRAM-34 group (n = 7). An experimental model of AF was established by rapid pacing. TRAM-34 was administered to the Pacing+TRAM-34 group by slow intravenous injection (10 mg/kg), 3 times each day. After 7 days of pacing, the electrophysiology was measured in vivo. The levels of interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), CD68, c-Fos, p38, and NF-κB p65 in both atriums were measured by Western blotting, and the levels of inducible nitric oxide synthase (iNOS) and arginase1 (Arg-1) were measured by real-time PCR. Macrophage and KCa3.1 in macrophage in the atrium were quantized following double labeled immunofluorescent.Results: Greater inducibility of AF, an extended duration of AF and lower atrial effective refractory period (AERP) were observed in the pacing group compared with those in the sham group. Both CD68-labeled macrophage and the expression of KCa3.1 in macrophage were elevated in the pacing group and inhibited by TRAM-34, led to higher iNOS expression, lower Arg-1 expression, elevated levels of IL-1β, MCP-1, and TNF-α in the atria, which could be reversed by TRAM-34 treatment (all P < 0.01). KCa3.1 channels were possibly activated via the p38/AP-1/NF-κB signaling pathway.Conclusions: Inhibition of KCa3.1 suppresses vulnerability to AF by attenuating macrophage pro-inflammatory polarization and inflammatory cytokine secretion in a canine model with prolonged rapid atrial pacing.

Possible contribution of hepatocyte secretion to the elevation of plasma exosomal arginase-1 in high-fat diet-fed mice

AimsThe elevation of arginase in vascular tissues decreases nitric oxide production, which is considered as an early step of atherosclerosis in obesity. Previously, we found that arginase-1, one of arginase isozymes, was elevated in the blood plasma of obese adults. The purpose of this study is to elucidate the mechanism by which obesity increases arginase-1 levels in the blood. Main methodsC57/BL6J male mice fed a high-fat diet (HFD) for 12 weeks were analyzed for factors related to nitric oxide/arginine metabolism and plasma exosomes. To explore the arginase secretory organs, the protein expression levels were analyzed in several organs. To further investigate the relationship between exosomal arginase-1 in plasma, blood glucose levels and arginase-1 in the liver, HepG2 (the human hepatoma cell line) was analyzed after treatment with high glucose. Key findingsThe increase in arginase activity in the plasma of HFD-fed mice was positively corelated with blood glucose levels and was accompanied by an increase in exosomal arginase-1 levels. Among the organs that highly express arginase, the liver of HFD-fed mice showed a significant increase in arginase-1. The expression of arginase-1 in exosomes and total lysates of HepG2 cells were increased by high glucose exposure. SignificanceIncreased exosomal arginase-1 in plasma contributes to increased plasma arginase activity in obesity. The liver is a candidate organ for the secretion of exosomal arginase-1 into plasma, and the p38 pathway induced by high glucose levels may be involved.

Citrulline Recycling Supports Nitric Oxide Biosynthesis in Mouse PAM212 Keratinocytes

Nitric oxide synthases generate nitric oxide and citrulline from arginine using NADPH and molecular oxygen as co-substrates. In most mammalian cells, arginine is an essential amino acid and limiting extracellular supplies of this amino acid can reduce nitric oxide biosynthesis. This can occur during inflammation and injury where a variety of factors can reduce available arginine including high levels of tissue arginase. In cells and tissue containing urea cycle enzymes, arginine can be synthesized from citrulline. Thus, in a rate limiting step, argininosuccinate synthetase catalyzes the conversion of citrulline and aspartate to argininosuccinate which is then metabolized to arginine via argininosuccinate lyase. In earlier studies we reported that, in response to γ-interferon, PAM212 keratinocytes readily produce nitric oxide in an arginine-dependent manner via an inducible form of nitric oxide synthase. Citrulline is formed in the cells during this process while arginine is metabolized. In the present studies we determined if citrulline was taken up by PAM212 keratinocytes and utilized for nitric oxide biosynthesis. We found that citrulline effectively supported nitric oxide production; approximately 10-fold higher concentrations of citrulline were required to produce nitric oxide when compared to arginine. Both citrulline and arginine were taken up by PAM212 keratinocytes; at equimolar concentrations (50 µM), more arginine than citrulline was taken up by the cells. However, at higher concentrations, uptake of these amino acids was saturable; the apparent Km and Vmax for arginine uptake was 170 µM and 1.2 nmol/106 cells/min, respectively, and citrulline uptake was 850 µM and 0.7 nmol/106 cells/min, respectively. Nitric oxide production supported by citrulline was inhibited by the nitric oxide synthase inhibitors, N-monomethylarginine, N-nitroarginine and N-nitroarginine benzyl ester. Each of these compounds also inhibited citrulline uptake into keratinocytes. Citrulline is known to be taken up by the L amino acid transporter, and nitric oxide synthase inhibitors compete with this transporter for uptake into keratinocytes. When pulse-labeled with 14C-citrulline, approximately 17% to 25% of the label accumulated as 14C-arginine in cytoplasmic pools of PAM212 cells demonstrating that these cells contain arginosuccinate synthetase/lyase activity. Nitric oxide synthase inhibitors had no effect on citrulline recycling in the cells. These data indicate citrulline can be used for nitric oxide biosynthesis in PAM212 keratinocytes. Citrulline is less efficient than arginine in supporting nitric oxide production due to limited uptake and slow conversion to arginine. In PAM212 keratinocytes, nitric oxide synthase inhibitors have multiple modes of action: inhibition of uptake of citrulline and nitric oxide synthase activity.

Comparing the Protective Effects of Curcumin and Ursodeoxycholic Acid after Ethanol-Induced Hepatotoxicity in Rat Liver.

Alcohol consumption can cause hepatitis and long-term cirrhosis of the liver. The aim of this study was to evaluate the protective effects of curcumin (CUR) and ursodeoxycholic acid (UDCA) alone and together in the prevention and treatment of liver damage caused by overuse of ethanol. Adult Wistar rats were divided into 8 groups of 5, including the control group and various combinations of ethanol, CUR and UDCA groups. Twenty-eight days after the oral treatment, serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and Arginase I (ArgI) as well as serum levels of Albumin (Alb), total protein (TP) and Blood Urea Nitrogen (BUN) were measured, and liver tissue was evaluated histopathologically. The solo administration of CUR, UDCA and CUR+UDCA had no effect on the blood parameters and liver tissue compared to the control group (p>0.05). The solo administration of CUR and UDCA in ethanol-treated rats significantly reduced ALT, AST, ALP, GGT, ArgI and BUN levels (p<0.05), while the solo administration increased Alb and TP levels compared to the ethanol group (p<0.05). In these groups, a significant decrease in cell necrosis and local inflammation of hepatocytes was observed, and the liver damage was mild. However, co-administration of ethanol, CUR and UDCA made significantly greater decrease in ALT, AST, ALP, GGT, ArgI and BUN levels (p>0.05), while the co-administration greatly increased Alb and TP levels compared to the ethanol group (p<0.05). Histopathologically, a decrease in structural changes in liver tissue and inflammation was observed, resulting in the improvement of liver tissue. The solo administration of CUR and UDCA could reduce ethanol-induced liver damage in rats and improve liver's serum and blood parameters. However, the coadministration of CUR and UDCA has a greater efficacy.

A Study of Arginase Expression in Chronic Non-healing Wounds.

Arginase expression has been recently shown to increase in numerous disease states like neurodegeneration, inflammation, and malignancies. Although it has been found to be functionally important in various disease pathologies, little is known about its role in wound healing. Here, we look at the expression of arginase and its isoforms in chronic non-healing wounds and also study the expression of nitric oxide synthase (NOS) and oxidative stress enzymes in them. Wound tissues and blood samples were collected at the time of index presentation and follow-up from 61 chronic non-healing wound cases. The expression patterns of arginase isoenzymes, NOS, superoxide dismutases (SOD), lactic acid dehydrogenase (LDH), and catalase were examined by using enzyme-linked immunosorbent assay, immunohistochemistry, and western blot analysis at the transcript and protein level. We reported a significant decrease of serum arginase levels in chronic nonhealing wounds in the progress of wound healing. Interestingly, tissue arginase levels were found to be increased with improved wound condition at follow-up. Tissue NOS, LDH, and catalase activity were also found to be increased with the progress of healing, whereas SOD levels were downregulated. Our findings reported increased expression at the transcript level of arginase-I and arginase-II in chronic non-healing wounds for the first time. In conclusion, we observed decreased serum arginase levels in completely healed patients as compared to non-healed cases. Our study findings support the hypothesis that inhibition of the activity of arginase delays wound healing. Arginase and iNOS may also find their place in the future as possible biomarkers for wound healing.