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Macrophages polarize into alternatively activated M2 macrophages through interleukin (IL)-4, and they express high levels of arginase-1, which promotes anti-inflammatory responses. Several studies have confirmed the anti-inflammatory effects of cyclin-dependent kinase (CDK) 8/19 inhibition, and hence, numerous CDK8/19 inhibitors, such as BRD6989, have been developed. However, the effects of CDK8/19 inhibitors on arginase-1 expression in macrophages have not yet been elucidated. This study investigated the effects of CDK8/19 inhibitor on arginase-1 expression in IL-4-activated macrophages. The results showed that BRD6989 increased arginase-1 expression transcriptionally in murine peritoneal macrophages and the murine macrophage cell line RAW264.7 in an IL-4-dependent manner. In addition, the results indicated that BRD6989 enhances signal transducer and activator of transcription (STAT) 6 phosphorylation. Meanwhile, BRD6989 exhibited the capability to activate p38 mitogen-activated protein kinase (MAPK） even in the absence of IL-4 stimulation. Moreover, we observed that a p38 MAPK inhibitor suppressed the BRD6989-induced increase in arginase-1 expression. Besides, BRD6989 increased the surface expression of CD206, an M2 macrophage marker. Thus, this study demonstrated for the first time that CDK8/19 inhibition increases arginase-1 expression, suggesting that this mechanism involves the activation of STAT6 and p38 MAPK. This finding implies that CDK8/19 inhibition may facilitate the production of anti-inflammatory M2 macrophages., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Neutrophilia occurs in patients infected with SARS-CoV-2 (COVID-19) and is predictive of poor outcomes. Here, we link heterogenous neutrophil populations to disease severity in COVID-19. We identified neutrophils with features of cellular aging and immunosuppressive capacity in mild COVID-19 and features of neutrophil immaturity and activation in severe disease. The low-density neutrophil (LDN) number in circulating blood correlated with COVID-19 severity. Many of the divergent neutrophil phenotypes in COVID-19 were overrepresented in the LDN fraction and were less detectable in normal-density neutrophils. Functionally, neutrophils from patients with severe COVID-19 displayed defects in neutrophil extracellular trap formation and reactive oxygen species production. Soluble factors secreted by neutrophils from these patients inhibited T cell proliferation. Neutrophils from patients with severe COVID-19 had increased expression of arginase-1 protein, a feature that was retained in convalescent patients. Despite this increase in intracellular expression, there was a reduction in arginase-1 release by neutrophils into serum and culture supernatants. Furthermore, neutrophil-mediated T cell suppression was independent of arginase-1. Our results indicate the presence of dysfunctional, activated, and immature neutrophils in severe COVID-19.

Urea cycle impairment and its relationship to obesity and inflammation remained elusive, partly due to the dramatic clinical presentation of classical urea cycle defects. We generated mice with hepatocyte-specific arginase 2 deletion (Arg2 LKO ) and revealed a mild compensated urea cycle defect. Stable isotope tracing and respirometry revealed hepatocyte urea and TCA cycle flux defects, impaired mitochondrial oxidative metabolism, and glutamine anaplerosis despite normal energy and glucose homeostasis during early adulthood. Yet during middle adulthood, chow- and diet-induced obese Arg2 LKO mice develop exaggerated glucose and lipid derangements, which are reversible by replacing the TCA cycle oxidative substrate nicotinamide adenine dinucleotide. Moreover, serum-based hallmarks of urea, TCA cycle, and mitochondrial derangements predict incident fibroinflammatory liver disease in 106,606 patients nearly a decade in advance. The data reveal hierarchical urea-TCA cycle control via ARG2 to drive oxidative metabolism. Moreover, perturbations in this circuit may causally link urea cycle compromise to fibroinflammatory liver disease., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Ammonia is a prevalent aquatic pollutant that disrupts cellular functions and energy metabolism in fish, posing significant environmental and health threats. This research investigates the critical role of arginase 2 (ARG2) in mitigating ammonia toxicity in fish cells and its implications in adapting to nitrogen metabolism under high ammonia exposure. Through a CRISPR-Cas9 engineered ARG2 knockdown (KD) in the Epithelioma Papulosum Cyprini (EPC) cell line, we first investigated the biochemical responses of ARG2 KD and wild-type (WT) EPC cells to ammonia stress (NH 4 Cl treatment), showing diminished urea production and decreased cell viability in ARG2 KD cells. Subsequently, single-cell Raman spectroscopy analysis revealed that ARG2 KD cells exhibited profound metabolic shifts, including changes in protein, nucleic acids, lipid and sugar levels, showing the adjusting role of ARG2 in the balance of carbohydrate and nitrogen metabolism. Furthermore, the upregulated responses of various amino acids, such as glutamine, arginine, alanine, glutamic acid, glycine, histidine, phenylalanine and valine, in WT cells after NH 4 Cl treatment diminished in ARG2 KD cells except for the decrease in aspartic acid, indicating a switching effect of ARG2 in nitrogen metabolism under ammonia stress. This study highlights ARG2's essential role in ammonia detoxification and emphasizes ARG2's protective function and its importance in metabolism, shedding light on the adaptive mechanisms fish cells deploy against high ammonia environments. These insights contribute to deep understanding of aquatic organisms' molecular responses to environmental ammonia pollution, offering potential strategies for their protection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

High-altitude environments present extreme conditions characterized by low barometric pressure and oxygen deficiency, which can disrupt brain functioning and cause edema formation. The objective of the present study is to investigate several biomolecule expressions and their role in the development of High Altitude Cerebral Edema in a rat model. Specifically, the study focuses on analyzing the changes in total arginase, nitric oxide, and lipid peroxidation (MDA) levels in the brain following acute hypobaric hypoxic exposure (7620 m, SO 2 =8.1 %, for 24 h) along with the histopathological assessment. The histological examination revealed increased TNF-α activity, and an elevated number of mast cells in the brain, mainly in the hippocampus and cerebral cortex. The research findings demonstrated that acute hypobaric hypoxic causes increased levels of apoptotic cells, shrinkage, and swelling of neurons, accompanied by the formation of protein aggregation in the brain parenchyma. Additionally, the level of nitric oxide and MDA was found to have increased (p<0.0001), however, the level of arginase decreased indicating active lipid peroxidation and redox imbalance in the brain. This study provides insights into the pathogenesis of HACE by evaluating some biomolecules that play a pivotal role in the inflammatory response and the redox landscape in the brain. The findings could have significant implications for understanding the neuronal dysfunction and the pathological mechanisms underlying HACE development., Competing Interests: Declaration of Competing Interest The authors declared no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

M2-like macrophages promote tumor growth and cancer immune evasion. This study used an in vitro model to investigate how hypoxia and tumor metabolism affect macrophage polarization. Liver cancer cells (HepG2 and VX2) and macrophages (THP1) were cultured under hypoxic (0.1% O 2 ) and normoxic (21% O 2 ) conditions with varying glucose levels (2 g/L or 4.5 g/L). Viability assays and extracellular pH (pHe) measurements were conducted over 96 hours. Macrophages were exposed to the tumor-conditioned medium (TCM) from the cancer cells, and polarization was assessed using arginase and nitrite assays. GC-MS-based metabolic profiling quantified TCM meta-bolites and correlated them with M2 polarization. The results showed that pHe in TCMs decreased more under hypoxia than normoxia ( p < 0.0001), independent of glucose levels. The arginase assay showed hypoxia significantly induced the M2 polarization of macrophages (control group: p = 0.0120, 0.1% VX2-TCM group: p = 0.0149, 0.1% HepG2-TCM group: p < 0.0001, 0.1% VX2-TCM HG group: p = 0.0001, and 0.1% HepG2-TCM HG group: p < 0.0001). TCMs also induced M2 polarization under normoxic conditions, but the strongest M2 polarization occurred when both tumor cells and macrophages were incubated under hypoxia with high glucose levels. Metabolomics revealed that several metabolites, particularly lactate, were correlated with hypoxia and M2 polarization. Under normoxia, elevated 2-amino-butanoic acid (2A-BA) strongly correlated with M2 polarization. These findings suggest that targeting tumor hypoxia could mitigate immune evasion in liver tumors. Lactate drives acidity in hypoxic tumors, while 2A-BA could be a therapeutic target for overcoming immunosuppression in normoxic conditions.

Despite the immune system's role in the detection and eradication of abnormal cells, cancer cells often evade elimination by exploitation of various immune escape mechanisms. Among these mechanisms is the ability of cancer cells to upregulate amino acid-metabolizing enzymes, or to induce these enzymes in tumor-infiltrating immunosuppressive cells. Amino acids are fundamental cellular nutrients required for a variety of physiological processes, and their inadequacy can severely impact immune cell function. Amino acid-derived metabolites can additionally dampen the anti-tumor immune response by means of their immunosuppressive activities, whilst some can also promote tumor growth directly. Based on their evident role in tumor immune escape, the amino acid-metabolizing enzymes glutaminase 1 (GLS1), arginase 1 (ARG1), inducible nitric oxide synthase (iNOS), indoleamine 2,3-dioxygenase 1 (IDO1), tryptophan 2,3-dioxygenase (TDO) and interleukin 4 induced 1 (IL4I1) each serve as a promising target for immunotherapeutic intervention. This review summarizes and discusses the involvement of these enzymes in cancer, their effect on the anti-tumor immune response and the recent progress made in the preclinical and clinical evaluation of inhibitors targeting these enzymes., Competing Interests: Author YG was employed by Oncolines B.V., (Copyright © 2024 Grobben.)

The mechanisms underlying endothelial dysfunction in Type 1 and Type 2 diabetes (T1DM and T2DM) are unresolved. The red blood cells (RBCs) with increased arginase activity induce endothelial dysfunction in T2DM, but the implications of RBCs and the role of arginase inhibition in T1DM are unexplored. We aimed to investigate the differences in endothelial function in patients with T1DM and T2DM, with focus on RBCs and arginase. Thirteen patients with T1DM and twenty-six patients with T2DM, matched for HbA1c and sex were included. In vivo endothelium-dependent and -independent vasodilation (EDV and EIDV) were assessed by venous occlusion plethysmography before and after administration of an arginase inhibitor. RBCs were co-incubated with rat aortic segments for 18h followed by evaluation of endothelium-dependent (EDR) and -independent relaxation (EIDR) in isolated organ chambers. In vivo EDV, but not EIDV, was significantly impaired in patients with T2DM compared with patients with T1DM. Arginase inhibition resulted in improved EDV only in T2DM. RBCs from patients with T2DM induced impaired EDR but not EIDR in isolated aortic segments, whereas RBCs from patients with T1DM did not affect EDR nor EIDR. The present study demonstrates markedly impaired EDV in patients with T2DM in comparison with T1DM. In addition, it highlights the divergent roles of RBCs and arginase in mediating endothelial dysfunction in T1DM and T2DM. While endothelial dysfunction is mediated via RBCs and arginase in T2DM, these phenomena are not prominent in T1DM thereby indicating distinct differences in underlying mechanisms., (© 2024 The Author(s).)

The infectivity of Leishmania is determined by its ability to invade and evade host and its thriving capacity within the macrophage. Our study revealed the role of Leishmania donovani mevalonate kinase (MVK), an enzyme of mevalonate pathway in visceral leishmaniasis pathogenesis. Peritoneal exudate cells (PEC)-derived macrophages from BALB/c mice were infected with wild type (WT), MVK over expressing (MVK OE) and knockdown (KD) parasites and MVK OE parasites were found to be more infective than WT and MVK KD parasites. Incubation of macrophages with MVK OE parasites declined inducible nitric oxide synthase (iNOS) expression as well as nitric oxide (NO) production, both by 2 times in comparison to WT parasites. Moreover, ∼3 fold increase in Arginase1 expression indicated that MVK might induce polarization of macrophage towards M2, favouring the survival of parasite within the macrophages. Post 24 h infection of the macrophages with mutant strains, the levels of different cytokines (TNF-α, IL-12, IL-10 and IFN-γ) were measured. Infection of macrophages with MVK OE parasites showed an increase in the level of anti-inflammatory cytokine: IL-10 while infection with MVK KD parasites exhibited an increase in the level of pro-inflammatory cytokines: TNF-α, IL-12, and IFN-γ. Hence, Leishmania donovani mevalonate kinase (LdMVK) modulates macrophage functions and has a significant role in pathogenesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Declarations of interest: none., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Spermidine suppress oxidative stress and is involved in various disease pathogenesis including ulcerative colitis (UC). Arginase 2 (ARG2) plays a central role in the synthesis of spermidine. This study aimed to clarify the effect of endogenously produced spermidine on colitis., Methods: The physiological role of ARG2 and spermidine was investigated using Arg2-deficient mice with reduced spermidine. Immunohistochemical staining of the rectum was used to analyze ARG2 expression and spermidine levels in healthy controls and UC patients., Results: In mice with dextran sulfate sodium-induced colitis, ARG2 and spermidine levels were increased in the rectal epithelium. Spermidine protects colonic epithelial cells from oxidative stress and Arg2 knockdown cells reduced antioxidant activity. Organoids cultured from the small intestine and colon of Arg2-deficient mice both were more susceptible to oxidative stress. Colitis was exacerbated in Arg2-deficient mice compared to wild-type mice. Supplementation with spermidine result in comparable severity of colitis in both wild-type and Arg2-deficient mice. In the active phase of UC, rectal ARG2 expression and spermidine accumulation were increased compared to remission. ARG2 and spermidine levels were similar in healthy controls and UC remission patients., Conclusions: ARG2 produces spermidine endogenously in the intestinal epithelium and has a palliative effect on ulcerative colitis. ARG2 and spermidine are potential novel therapeutic targets for UC., (© 2024. Japanese Society of Gastroenterology.)

Venous leg ulcers (VLUs) pose a growing healthcare challenge due to aging, obesity, and sedentary lifestyles. Despite various treatments available, addressing the complex nature of VLUs remains difficult. In this context, this study investigates repurposing boronated drugs to inhibit arginase 1 activity for VLU treatment. The molecular docking study conducted by Schrodinger GLIDE targeted the binuclear manganese cluster of arginase 1 enzyme (2PHO). Further, the ligand-protein complex was subjected to molecular dynamic studies at 500 ns in Gromacs-2019.4. Trajectory analysis was performed using the GROMACS simulation package of protein RMSD, RMSF, RG, SASA, and H-Bond. The docking study revealed intriguing results where the tavaborole showed a better docking score (-3.957 Kcal/mol) compared to the substrate L-arginine (-3.379 Kcal/mol) and standard L-norvaline (-3.141 Kcal/mol). Tavaborole interaction with aspartic acid ultimately suggests that the drug molecule binds to the catalytic site of arginase 1, potentially influencing the enzyme's function. The dynamics study revealed the compounds' stability and compactness of the protein throughout the simulation. The RMSD, RMSF, SASA, RG, inter and intra H-bond, PCA, FEL, and MMBSA studies affirmed the ligand-protein and protein complex flexibility, compactness, binding energy, van der waals energy, and solvation dynamics. These results revealed the stability and the interaction of the ligand with the catalytic site of arginase 1 enzyme, triggering the study towards the VLU treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The mitochondrial enzyme arginase-2 (Arg-2) is implicated in the pathophysiology of contrast-induced acute kidney injury (CI-AKI). Therefore, Arg-2 represents a candid target for CI-AKI prevention. Here, layer-by-layer (LbL) assembled renal-targeting polymeric nanoparticles are developed to efficiently deliver small interfering RNA (siRNA), knockdown Arg-2 expression in renal tubules, and prevention of CI-AKI is evaluated. First, near-infrared dye-loaded poly(lactic-co-glycolic acid) (PLGA) anionic cores are electrostatically coated with cationic chitosan (CS) to facilitate the adsorption and stabilization of Arg-2 siRNA. Next, nanoparticles are coated with anionic hyaluronan (HA) to provide protection against siRNA leakage and shielding against early clearance. Sequential electrostatic layering of CS and HA improves loading capacity of Arg-2 siRNA and yields LbL-assembled nanoparticles. Renal targeting and accumulation is enhanced by modifying the outermost layer of HA with a kidney targeting peptide (HA-KTP). The resultant kidney-targeting and siRNA loaded nanoparticles (PLGA/CS/HA-KTP siRNA) exhibit proprietary accumulation in kidneys and proximal tubular cells at 24 h post-tail vein injection. In iohexol-induced in vitro and in vivo CI-AKI models, PLGA/CS/HA-KTP siRNA delivery alleviates oxidative and nitrification stress, and rescues mitochondrial dysfunction while reducing apoptosis, thereby demonstrating a robust and satisfactory therapeutic effect. Thus, PLGA/CS/HA-KTP siRNA nanoparticles offer a promising candidate therapy to protect against CI-AKI., (© 2024 Wiley‐VCH GmbH.)

Myeloid-derived suppressor cells (MDSCs), the negative immune regulators, have been demonstrated to be involved in immune responses to a variety of pathological conditions, such as tumors, chronic inflammation, and infectious diseases. However, the roles and mechanisms underlying the expansion of MDSCs in malaria remain unclear. In this study, the phenotypic and functional characteristics of splenic MDSCs during Plasmodium yoelii NSM infection are described. Furthermore, we provide compelling evidence that the sera from P. yoelii-infected C57BL/6 mice containing excess IL-6 and granulocyte-macrophage colony-stimulating factor promote the accumulation of MDSCs by inducing Bcl2 expression. Serum-induced MDSCs exert more potent suppressive effects on T cell responses than control MDSCs within both in vivo P. yoelii infection and in vitro serum-treated bone marrow cells experiments. Serum treatment increases the MDSC inhibitory effect, which is dependent on Arg1 expression. Moreover, mechanistic studies reveal that the serum effects are mediated by JAK/STAT3 signaling. By inhibiting STAT3 phosphorylation with the JAK inhibitor JSI-124, effects of serum on MDSCs are almost eliminated. In vivo depletion of MDSCs with anti-Gr-1 or 5-fluorouracil significantly reduces the parasitemia and promotes Th1 immune response in P. yoelii-infected C57BL/6 mice by upregulating IFN-γ expression. In summary, this study indicates that P. yoelii infection facilitates the accumulation and function of MDSCs by upregulating the expression of Bcl2 and Arg1 via JAK/STAT3 signaling pathway in vivo and in vitro. Manipulating the JAK/STAT3 signaling pathway or depleting MDSCs could be promising therapeutic interventions to treat malaria., (Copyright © 2024 by The American Association of Immunologists, Inc.)

This study aimed to investigate the effects of the n-hexane fraction of the ethanolic seed extract of PG (NFESEPG) on hypertension induced by Nω-nitro-L-arginine methyl ester (L-NAME) in rats. Specifically, the study examined the impact of NFESEPG on blood pressure, oxidative stress markers, NO concentration, angiotensin-converting enzyme (ACE) and arginase activities, and cardiac biomarkers in hypertensive rats. The study involved collecting, identifying, and processing the PG plant to obtain the ethanolic seed extract. The extract was then partitioned with solvents to isolate the n-hexane fraction. Hypertension was induced in rats by oral administration of L-NAME for 10 days, while concurrent treatment with NFESEPG at two doses (200 and 400 mg/kg/day) was administered orally. Blood pressure was measured using a noninvasive tail-cuff method, and various biochemical parameters were assessed. Treatment with both doses of NFESEPG significantly reduced systolic and diastolic blood pressure in L-NAME-induced hypertensive rats. Additionally, NFESEPG administration increased NO concentration and decreased ACE and arginase activities, malondialdehyde (MDA) levels, and cardiac biomarkers in hypertensive rats. The findings indicate that NFESEPG effectively lowered blood pressure in hypertensive rats induced by L-NAME, potentially through mechanisms involving the modulation of oxidative stress, NO bioavailability, and cardiac biomarkers. These results suggest the therapeutic potential of NFESEPG in managing hypertension and related cardiovascular complications., (© 2024 The Author(s). Cell Biochemistry and Function published by John Wiley & Sons Ltd.)

Background: Cellular therapy has emerged as a promising strategy to minimize the use of conventional immunosuppressive drugs and ultimately induce long-term graft survival. Myeloid-derived suppressor cells (MDSCs) can be used for immunosuppressive treatment of solid organ transplants., Methods: Granular macrophage colony-stimulating factor (GM-CSF) and bexarotene, an X receptor-selective retinoid, were used for in vitro MDSC induction. Cell phenotypes were detected using flow cytometry, while mRNA was detected via real-time PCR. A mouse skin transplantation model was used to verify the inhibitory effects of this treatment., Results: The combination of GM-CSF and bexarotene-induced MDSC differentiation. MDSCs induce immune tolerance by inhibiting T-cell proliferation, influencing cytokine secretion, and inducing T-cell transformation into Treg cells. Combination treatment significantly up-regulated Arg-1 expression in MDSCs. The Arg-1 inhibitor nor-NOHA neutralized the immunosuppressive activity of MDSCs, suggesting the involvement of Arg-1 in MDSC-mediated immunosuppression. GM-CSF and bexarotene-induced MDSCs prolong graft survival in mouse skin transplants, exhibiting in vivo immunosuppressive effects., Conclusions: A new method for inducing MDSCs is presented. The combination of GM-CSF and bexarotene induces MDSCs with remarkable regulatory functions. Adoptive transfer of the induced MDSCs extended allograft survival. These results suggest that MDSCs can potentially be used in future clinical transplants to inhibit rejection, reduce adverse events, and induce operative tolerance., Competing Interests: Declaration of competing interest All authors disclosed no relevant relationships., (Copyright © 2024. Published by Elsevier Inc.)

Neuroinflammation has been gaining attention as one of the potential causes of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis in recent years. The suppression of excessive proinflammatory responses is expected to be a target for the treatment and prevention of neurodegenerative diseases. Collapsin response mediator protein 4 (CRMP4) is involved in cytoskeleton-associated axonal guidance in the developing brain. Recently, the involvement of CRMP4 in several pathological conditions, including inflammation induced by lipopolysaccharide (LPS), a widely used inflammatory molecule, has been reported. However, the role of CRMP4 in LPS-induced inflammation in vivo remains largely unknown. In this study, we generated microglia-specific CRMP4 knockout mice for the first time and examined the role of CRMP4 in an LPS-induced brain inflammation model. We found that microglia after LPS injection in substantia nigra was significantly reduced in Crmp4 -/- mice compared to Crmp4 +/+ mice. The increased expression of IL-10 in striatum samples was downregulated in Crmp4 -/- mice. A significant reduction in Iba1 expression was also observed in microglia-specific Crmp4 knockout mice compared with that in control mice. In contrast, the expression of IL-10 did not change in these mice, whereas arginase 1 (Arg1) expression was significantly suppressed. These results demonstrate the involvement of CRMP4 in LPS-induced inflammation in vivo, that CRMP4 suppresses microglial proliferation in a cell-autonomous manner., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Macrophages are one of the important immune cells, which play important roles in innate and adaptive immune. However, the roles of macrophages in food allergy are not thoroughly understood. To investigate the roles of macrophages during food allergy, we focused on the relationship between macrophage polarization and allergic responses induced by tropomyosin (TM) in the present study. Arg 1 and CD206 expressions in the TM group were significantly higher than those of the PBS group, while iNOS and TNF-α expressions were no obvious difference, moreover, the morphology of macrophages stimulated by TM was similar to that of M2 macrophages. These results indicated macrophages were mainly polarized toward M2 phenotypes in vitro. The antibodies, mMCP-1, histamine and cytokines, revealed that macrophages could participate in food allergy, and macrophage polarization was associated with changes in allergic-related factors. The cytokine levels of M2 phenotypes were significantly higher than those of M1 phenotypes in peripheral blood. The mRNA expressions and protein levels of Arg1 and iNOS in the jejunum and peritoneal cells indicated that M2 phenotypes were the major macrophage in these tissues compared with M1 phenotypes. Hence, macrophage polarization plays an important role in food allergy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: L. arginase refers to the enzyme arginase found in the genus Lactobacillus, it plays a crucial role in the urea cycle, and has implications in various biological applications. This study aimed to purify arginase from Pseudomonas aeruginosa, isolated from soil, and apply it as an anticancer., Methodology: 28 soil samples of P. aeruginosa were collected from different places of Baghdad, and rice lands in Najaf and Diwaniyah governorates. Different standard laboratory and biochemical assays, and Vitik system were used in diagnosis and growth of arginase enzyme under certain pH, temperature, incubation period., Results: The purified enzyme was precipitated by ammonium sulfite (60-80%), dialyses bag 8000-1000KD, ion exchange by DEAE cellulose and sephadex G100 in gel filtration. Cytotoxicity of arginase against breast t cancer AJM-13 and rat embryo fibroblast REF normal cell line was evaluated for (48 and 72 hours). The inhibition rate increased in the low concentration of abnormal cell (AMJ-13) while decreased in the normal cell (REF), this study takes different concentration (0.392-12.5mg/mL), and low concentration (1562-0.048 mg/mL), the result in high concentration was IR 54.7% during 72 hours for AJM-13 and 14.3% for REF in the same time, while the low concentration was IR 91% in the 1562 mg/mL in the AMJ-13, and 51% in ERF, LD50 of arginase enzyme was 0.781 mg/mL that 41% during 72 hours for ERF, its save to normal cells., Conclusions: Arginase enzyme, at low concentrations, may have an inhibitory effect on cancer cells, and simultaneously, protect normal cell lines., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2024 Zainab Abbas Abd, Zaid Raad Abbas, Aqeel Mohammad Majeed.)

Small synthetic oligodeoxynucleotides (ODNs) can mimic microbial nucleic acids by interacting with receptor systems and promoting immunostimulatory activities. Nevertheless, some ODNs can act differently on the plasmacytoid dendritic cell (pDC) subset, shaping their immunoregulatory properties and rendering them suitable immunotherapeutic tools in several clinical settings for treating overwhelming immune responses. We designed HIV-1-derived, DNA- and RNA-based oligonucleotides (gag, pol, and U5 regions) and assessed their activity in conferring a tolerogenic phenotype to pDCs in skin test experiments. RNA-but not DNA-oligonucleotides are capable of inducing tolerogenic features in pDCs. Interestingly, sensing the HIV-1-derived single-stranded RNA-gag oligonucleotide (RNA-gag) requires both TLR3 and TLR7 and the engagement of the TRIF adaptor molecule. Moreover, the induction of a suppressive phenotype in pDCs by RNA-gag is contingent upon the induction and activation of the immunosuppressive enzyme Arginase 1. Thus, our data suggest that sensing of the synthetic RNA-gag oligonucleotide in pDCs can induce a suppressive phenotype in pDCs, a property rendering RNA-gag a potential tool for therapeutic strategies in allergies and autoimmune diseases.

Hepatitis C virus (HCV) is an oncogenic virus that causes chronic liver disease in more than 80% of patients. During the last decade, efficient direct-acting antivirals were introduced into clinical practice. However, clearance of the virus does not reduce the risk of end-stage liver diseases to the level observed in patients who have never been infected. So, investigation of HCV pathogenesis is still warranted. Virus-induced changes in cell metabolism contribute to the development of HCV-associated liver pathologies. Here, we studied the impact of the virus on the metabolism of polyamines and proline as well as on the urea cycle, which plays a crucial role in liver function. It was found that HCV strongly suppresses the expression of arginase, a key enzyme of the urea cycle, leading to the accumulation of arginine, and up-regulates proline oxidase with a concomitant decrease in proline concentrations. The addition of exogenous proline moderately suppressed viral replication. HCV up-regulated transcription but suppressed protein levels of polyamine-metabolizing enzymes. This resulted in a decrease in polyamine content in infected cells. Finally, compounds targeting polyamine metabolism demonstrated pronounced antiviral activity, pointing to spermine and spermidine as compounds affecting HCV replication. These data expand our understanding of HCV's imprint on cell metabolism.

Bacteria-enhanced inducible nitric oxide synthase (iNOS) overproduces nitric oxide (NO) leading to mitochondrial and cellular damage. In mammals, arginase (ARG), the enzyme consuming the same substrate l-arginine with iNOS, was believed to inhibit iNOS activity by competing the substrate. But in fish, this conception has been widely challenged. In this study, the gene expression using real-time quantitative PCR (RT-qPCR) technology showed that when stimulated by Aeromonas hydrophila (A. hydrophila), grass carp (gc) iNOS was up-regulated in head kidney monocytes/macrophages (M0/MФ), and its changes were not detected in the whole tissue of liver or spleen, showing a high degree of cell-specific expression pattern. At the same time, gcARG2 had a high basal expression in tissues and was up-regulated by A. hydrophila stimulation. Next, phthalaldehyde-primaquine reaction was first used in the determination of intracellular urea in fish cells. It was found that the induced gcARG2 led to an increase in the intracellular urea content. Moreover, urea and NO production in M0/MФ were increased in a substrate dose-dependent manner from 30 to 100 μM of l-arginine and reached the highest yield at 300 and 3000 μM of l-arginine, respectively. Furthermore, head kidney M0/MФ was cultured in RPMI1640 medium containing physiological concentration (500 μM) of l-arginine to evaluate the effect of ARG. Under A. hydrophila stimulation, treatment with the arginase inhibitor S-(2-boronoethyl)-l-cysteine (BEC) showed that inhibition of arginase could further enhance the NO production stimulated by A. hydrophila. This in turn led to a cumulation in peroxynitrite (ONOO-) content and an injury of the mitochondrial membrane potential. Our study showed for the first time that fish ARG in head kidney M0/MФ can limit excessive production of NO and harmful products by iNOS to maintain mitochondrial and cellular homeostasis., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Endometrial cancer (EC) is the most common gynecologic malignancy. While the majority of patients present with early-stage and low-grade EC and have an excellent prognosis, a subset has metastatic disease at presentation or develops distant recurrence after initial treatment of the primary. However, the lack of prognostic biomarkers for metastatic EC is a critical barrier. Arginase 1 (ARG1) regulates the last step of the urea cycle, and an increase in ARG1 has been correlated as a poor prognostic factor in a variety of cancers. In the present study, ARG1 expression was evaluated as a potential prognostic marker for metastatic EC in endometrial hyperplasia and cancer of mice with Pten mutation as well as Pten and Mig-6 double mutations. While Pten mutation in the uterus is not sufficient for distant metastasis, mice with concurrent ablation of Mig-6 and Pten develop distant metastasis. Our immunostaining and RT-qPCR analysis revealed that the expression of ARG1 in early stage of EC as well as endometrial hyperplasia from mice deficient in Mig-6 and Pten mutations significantly increased compared to Pten mutation in the uterus. The results suggest that a high level of ARG1 is associated with poor prognosis in association with EC of mouse., (© 2024. The Author(s), under exclusive licence to Society for Reproductive Investigation.)

Myeloid-derived suppressor cells (MDSCs) are implicated in the regulation of immune responses closely associated with poor clinical outcomes in cancer. However, the MDSC subtypes in non-Hodgkin's lymphoma (NHL) have not been systematically investigated. So, we investigated the percentage of MDSC subsets in 78 newly diagnosed NHL patients by flow cytometry. The results showed that all MDSC subsets increased in NHL patients compared with healthy donors. Notably, MDSCs, monocytic MDSCs, and CD14 + CD66b + MDSCs significantly increased in NHL patients compared with those with lymphadenitis donors. polymorphonuclear MDSCs (PMN-MDSCs), early-stage MDSCs (e-MDSCs), and the International Prognostic Index were independent risk factors for poor clinical efficacy and were involved in constructing the nomogram for predicting clinical efficacy. Progression-free survival (PFS) was significantly shorter in patients with high level of MDSC subsets, and PMN-MDSCs emerged as an independent prognostic factor for PFS. PMN-MDSCs, e-MDSCs, and the International Prognostic Index were involved in constructing the nomogram for predicting PFS. Patients with a higher percentage of MDSCs, PMN-MDSCs, e-MDSCs, and CD14 + CD66b + MDSCs experienced a shorter overall survival compared with those with lower percentages. In addition, research on mechanisms found that T cell function was suppressed and mediated by the expansion of MDSCs via involving arginase-1 and interleukin-10 in vitro and in vivo. In conclusion, our study demonstrates that the increased circulating MDSC subsets predict poor clinical efficacy and prognosis in NHL, potentially involving T cell suppression through MDSC subset expansion. These findings indicate the potential of MDSC subsets as comprehensive diagnostic, prognostic biomarkers, and therapeutic targets for NHL., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Leukocyte Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Leishmaniasis is a disease caused by a protozoan of the genus Leishmania, affecting millions of people, mainly in tropical countries, due to poor social conditions and low economic development. First-line chemotherapeutic agents involve highly toxic pentavalent antimonials, while treatment failure is mainly due to the emergence of drug-resistant strains. Leishmania arginase (ARG) enzyme is vital in pathogenicity and contributes to a higher infection rate, thus representing a potential drug target. This study helps in designing ARG inhibitors for the treatment of leishmaniasis. Py-CoMFA (3D-QSAR) models were constructed using 34 inhibitors from different chemical classes against ARG from L. (L.) amazonensis (LaARG). The 3D-QSAR predictions showed an excellent correlation between experimental and calculated pIC 50 values. The molecular docking study identified the favorable hydrophobicity contribution of phenyl and cyclohexyl groups as substituents in the enzyme allosteric site. Molecular dynamics simulations of selected protein-ligand complexes were conducted to understand derivatives' interaction modes and affinity in both active and allosteric sites. Two cinnamide compounds, 7g and 7k, were identified, with similar structures to the reference 4h allosteric site inhibitor. These compounds can guide the development of more effective arginase inhibitors as potential antileishmanial drugs., (© 2024. The Author(s).)

β -Glucan is the main component of the cell wall of pathogen-associated molecular patterns (PAMPs) including various yeast, fungi, or certain bacteria. Previous reports demonstrated that β -glucan was widely investigated as a potent immunomodulators to stimulate innate and adaptive immune responses, which indicated that it could be recommended as an effective adjuvant in immunotherapy. However, the detailed effects of β -glucan on neonatal immunity are still largely unknown. Here, we found that β -glucan did not affect the frequencies and numbers of myeloid cells in the spleen and bone marrow from neonates. Functional assay revealed that β -glucan from neonates compromised the immunosuppressive function of immature myeloid cells, which were myeloid-derived suppressor cells (MDSCs). Flow cytometry or gene expression analysis revealed that β -glucan-derived polymorphonuclear (PMN)-MDSCs produced lower level of reactive oxygen species (ROS) and arginase-1 ( Arg1 ) in neonatal mice. Furthermore, β -glucan administration significantly decreased the frequency and ROS level of PMN-MDSCs in vitro. These observations suggest that β -glucan facilitates the maturation of myeloid cells in early life, which may contribute to its beneficial effects against immune disorders later in life., Competing Interests: The authors declare that they have no conflict of interest., (Copyright © 2024 Yingying Chen et al.)

Elevation of arginase enzyme activity in the lung contributes to the pathogenesis of various chronic inflammatory diseases and infections. Inhibition of arginase expression and activity is able to alleviate those effects. Here, we investigated the immunomodulatory effect of arginase inhibitor in C. neoformans infection. In the pulmonary cryptococcosis model that was shown to recapitulate human infection, we found arginase expression was excessively induced in the lung during the late stage of infection. To inhibit the activity of arginase, we administered a specific arginase inhibitor, nor-NOHA, during C. neoformans infection. Inhibition of arginase reduced eosinophil infiltration and level of IL-13 secretion in the lungs. Whole lung transcriptome RNA-sequencing analysis revealed that treatment with nor-NOHA resulted in shifting the Th2-type gene expression patterns induced by C. neoformans infection to the Th1-type immune profile, with higher expression of cytokines Ifng, Il6, Tnfa, Csf3, chemokines Cxcl9 and Cxcl10 and transcription factor Stat1. More importantly, mice treated with arginase inhibitor had more infiltrating brain leukocytes and enhanced gene expression of Th1-associated cytokines and chemokines that are known to be essential for protection against C. neoformans infection. Inhibition of arginase dramatically attenuated spleen and brain infection, with improved survival. Taken together, these studies demonstrated that inhibiting arginase activity induced by C. neoformans infection can modulate host immune response by enhancing protective type-1 immune response during C. neoformans infection. The inhibition of arginase activity could be an immunomodulatory target to enhance protective anti-cryptococcal immune responses., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The association between tuberculous fibrosis and lung cancer development has been reported by some epidemiological and experimental studies; however, its underlying mechanisms remain unclear, and the role of macrophage (MФ) polarization in cancer progression is unknown. The aim of the present study was to investigate the role of M2 Arg-1 + MФ in tuberculous pleurisy-assisted tumorigenicity in vitro and in vivo., Methods: The interactions between tuberculous pleural effusion (TPE)-induced M2 Arg-1 + MФ and A549 lung cancer cells were evaluated. A murine model injected with cancer cells 2 weeks after Mycobacterium bovis bacillus Calmette-Guérin pleural infection was used to validate the involvement of tuberculous fibrosis to tumor invasion., Results: Increased CXCL9 and CXCL10 levels of TPE induced M2 Arg-1 + MФ polarization of murine bone marrow-derived MФ. TPE-induced M2 Arg-1 + MФ polarization facilitated lung cancer proliferation via autophagy signaling and E-cadherin signaling in vitro. An inhibitor of arginase-1 targeting M2 Arg-1 + MФ both in vitro and in vivo significantly reduced tuberculous fibrosis-induced metastatic potential of lung cancer and decreased autophagy signaling and E-cadherin expression., Conclusion: Tuberculous pleural fibrosis induces M2 Arg-1 + polarization, and M2 Arg-1 + MФ contribute to lung cancer metastasis via autophagy and E-cadherin signaling. Therefore, M2 Arg-1 + tumor associated MФ may be a novel therapeutic target for tuberculous fibrosis-induced lung cancer progression., (© 2024. The Author(s).)

Neuregulin receptor degradation protein 1 (Nrdp1) is a ring finger E3 ubiquitin ligase involved in some inflammation through ubiquitination, including macrophage polarization following cerebral hemorrhage. However, there is limited understanding regarding the mechanisms through which Nrdp1 modulates macrophage polarization and the potential impact of this modulation on neurological function. Using stereotactic injection and adenoviral transfection techniques, the corresponding animal models were constructed through injecting adenovirus, saline, or blood into the mouse striatum at different periods of time in this research. The alteration in the ratio of various M1/M2 phenotype-associated markers (e.g., CD86, CD206, IL-6, IL-10, etc.) was evaluated through immunohistochemistry, immunofluorescence, western blotting, and elisa assays. Additionally, neurological function scores and behavioral tests were utilized to evaluate changes in neurological function in mice after cerebral hemorrhage. Our results show that overexpression of Nrdp1 promotes the expression of a variety of M2 macrophage-associated markers and enhance transcriptional activity of arginase-1 (Arg1) protein through ubiquitination for early regulation M2 macrophage polarization. Additionally, Nrdp1 promotes hematoma absorption, increases IL-10 expression, inhibits inducible nitric oxide synthase (iNOS), IL-6, and TNF-α production, alleviates neurological impairment and brain edema, and accelerates functional recovery. These findings suggest that modulating macrophage polarization through Nrdp1 could be a therapeutic strategy for neurofunctional impairment in cerebral hemorrhage., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Cystic echinococcosis (CE) is a zoonotic disease, caused by Echinococcus granulosus sensu lato (E. granulosus s. l.), which posed significant public health concern globally. E. granulosus s. l. annexin B18 (EgANXB18) acts as a secretory protein, exerting a crucial influence in mediating host-parasite interactions. Recombinant annexin B18 (rEgANXB18) was expressed by Escherichia coli and the immunoreactivity was assessed by western blotting. The binding affinity between rEgANXB18 and total protein of RAW264.7 cells was assessed by ELISA. The impact of rEgANXB18 on the metabolic activity of RAW264.7 cells was assayed by Cell Counting Kit-8 assay. The mRNA levels of polarization markers (inducible nitrous oxide synthase (iNOS) and arginase 1 (Arg1)) and key cellular factors (IL-1β，IL-6，IL-10 and TNFα) were evaluated by qRT-PCR. rEgANXB18 was successfully expressed and recognized by E. granulosus s.l. infected canine sera, as well as could bind to the total protein of RAW264.7 cells. Additionally, rEgANXB18 could promote metabolic activity at 5, 10, 20, and 40 μg/mL while no significant impact on metabolic activity was observed at 80 μg/mL. Co-culture RAW264.7 cells with rEgANXB18 resulted in significantly upregulation of the transcript levels of polarization markers iNOS and Arg1. Moreover, rEgANXB18 significantly upregulated the transcript levels of IL-1β, IL-6, TNFα, and IL-10, while dose-effect relationship was observed in IL-1β, IL-6, and IL-10. Our results indicated that EgANXB18 showed the potential to regulate immune response of macrophages by shifting the cell polarization and cytokine profile, thereby promoting the parasitism of CE., Competing Interests: Declaration of competing interest The authors declare no competing interests. All authors have approved the submission of this manuscript. The results have not been previously published and are not being considered for publication in another journal., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Substances of silver nanoparticles dialyzed through a 13 kDa membrane, synthesized in a medium of humic ligands modified with hydroquinone and 2-hydroxynaphthoquinone from PowHumus brown coal, specifically enhance the M2 properties of peritoneal macrophages due to inhibition of NO synthase and significant activation of arginase, thus enhancing anti-inflammatory properties of cells. In small, but effective concentrations, they do not have cytotoxic properties and do not contain pyrogenic impurities. The studied humates are able to influence the mechanisms of immune response formation and are an effective means for correcting inflammation and regeneration., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

Pancreatic ductal adenocarcinoma is a highly metastatic disease and macrophages support liver metastases. Efferocytosis, or engulfment of apoptotic cells by macrophages, is an essential process in tissue homeostasis and wound healing, but its role in metastasis is less well understood. Here, we found that the colonization of the hepatic metastatic site is accompanied by low-grade tissue injury and that efferocytosis-mediated clearance of parenchymal dead cells promotes macrophage reprogramming and liver metastasis. Mechanistically, progranulin expression in macrophages is necessary for efficient efferocytosis by controlling lysosomal acidification via cystic fibrosis transmembrane conductance regulator and the degradation of lysosomal cargo, resulting in LXRα/RXRα-mediated macrophage conversion and upregulation of arginase 1. Pharmacological blockade of efferocytosis or macrophage-specific genetic depletion of progranulin impairs macrophage conversion, improves CD8 + T cell functions, and reduces liver metastasis. Our findings reveal how hard-wired functions of macrophages in tissue repair contribute to liver metastasis and identify potential targets for prevention of pancreatic ductal adenocarcinoma liver metastasis., (© 2024. The Author(s).)

Objectives: This study aims to evaluate the neuroprotective effect of caffeic acid (CAF) against cadmium chloride (CdCl 2 ) in rats via its effect on memory index as well as on altered enzymatic activity in the brain of CdCl 2 -induced neurotoxicity., Methods: The experimental rats were divided into seven groups (n=6 rats per group) of healthy rats (group 1), CdCl 2 -induced (CD) (3 mg/kg BW) rats (group 2), CD rats + Vitamin C (group 3), CD rats + CAF (10 and 20 mg/kg BW respectively) (group 4 & 5), and healthy rat + CAF (10 and 20 mg/kg BW respectively) (group 6 & 7). Thereafter, CdCl 2 and CAF were administered orally to the experimental rats in group 2 to group 5 on daily basis for 14 days. Then, the Y-maze test was performed on the experimental rats to ascertain their memory index., Results: CdCl 2 administration significantly altered cognitive function, the activity of cholinesterase, monoamine oxidase, arginase, purinergic enzymes, nitric oxide (NOx), and antioxidant status of Cd rats (untreated) when compared with healthy rats. Thereafter, CD rats treated with vitamin C and CAF (10 and 20 mg/kg BW) respectively exhibited an improved cognitive function, and the observed altered activity of cholinesterase, monoamine oxidase, arginase, purinergic were restored when compared with untreated CD rats. Also, the level of brain NOx and antioxidant status were significantly (p<0.05) enhanced when compared with untreated CD rats. In the same vein, CAF administration offers neuro-protective effect in healthy rats vis-à-vis improved cognitive function, reduction in the activity of some enzymes linked to the progression of cognitive dysfunction, and improved antioxidant status when compared to healthy rats devoid of CAF., Conclusions: This study demonstrated the neuroprotective effect of CAF against CdCl 2 exposure and in healthy rats., (© 2024 Walter de Gruyter GmbH, Berlin/Boston.)

Indoleamine 2,3-dioxygenase (IDO) and arginase-1 (ARG1) are amino acid-metabolizing enzymes, frequently highly expressed in cancer. Their expression may deplete essential amino acids, lead to immunosuppression, and promote cancer growth. Still, their expression patterns, prognostic significance, and spatial localization in the colorectal cancer microenvironment are incompletely understood. Using a custom 10-plex immunohistochemistry assay and supervised machine learning-based digital image analysis, we characterized IDO and ARG1 expression in monocytic cells, granulocytes, mast cells, and tumor cells in 833 colorectal cancer patients. We evaluated the prognostic value and spatial arrangement of IDO- and ARG1-expressing myeloid and tumor cells. IDO was mainly expressed not only by monocytic cells but also by some tumor cells, whereas ARG1 was predominantly expressed by granulocytes. Higher density of IDO + monocytic cells was an independent prognostic factor for improved cancer-specific survival both in the tumor center (P trend  = .0002; hazard ratio [HR] for the highest ordinal category Q4 [vs Q1], 0.51; 95% CI, 0.33-0.79) and the invasive margin (P trend  = .0015). Higher density of granulocytes was associated with prolonged cancer-specific survival in univariable models, and higher FCGR3 + ARG1 + neutrophil density in the tumor center also in multivariable analysis (P trend  = .0020). Granulocytes were, on average, located closer to tumor cells than monocytic cells. Furthermore, IDO + monocytic cells and ARG1 - granulocytes were closer than IDO - monocytic cells and ARG1 + granulocytes, respectively. The mRNA expression of the IDO1 gene was assessed in myeloid and tumor cells using publicly available single-cell RNA sequencing data for 62 colorectal cancers. IDO1 was mainly expressed in monocytes and dendritic cells, and high IDO1 activity in monocytes was associated with enriched immunostimulatory pathways. Our findings provided in-depth information about the infiltration patterns and prognostic value of cells expressing IDO and/or ARG1 in the colorectal cancer microenvironment, highlighting the significance of host immune response in tumor progression., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background and Purpose: While HCC is an inflammation-associated cancer, CRLM develops on permissive healthy liver microenvironment. To evaluate the immune aspects of these two different environments, peripheral blood-(PB), peritumoral-(PT) and tumoral tissues-(TT) from HCC and CRLM patients were evaluated., Methods: 40 HCC and 34 CRLM were enrolled and freshly TT, PT and PB were collected at the surgery. PB-, PT- and TT-derived CD4 + CD25 + Tregs, M/PMN-MDSC and PB-derived CD4 + CD25 - T-effector cells (Teffs) were isolated and characterized. Tregs' function was also evaluated in the presence of the CXCR4 inhibitor, peptide-R29, AMD3100 or anti-PD1. RNA was extracted from PB/PT/TT tissues and tested for FOXP3, CXCL12, CXCR4, CCL5, IL-15, CXCL5, Arg-1, N-cad, Vim, CXCL8, TGFβ and VEGF-A expression., Results: In HCC/CRLM-PB, higher number of functional Tregs, CD4 + CD25 hi FOXP3 + was detected, although PB-HCC Tregs exert a more suppressive function as compared to CRLM Tregs. In HCC/CRLM-TT, Tregs were highly represented with activated/ENTPD-1 + Tregs prevalent in HCC. As compared to CRLM, HCC overexpressed CXCR4 and N-cadherin/vimentin in a contest rich in arginase and CCL5. Monocytic MDSCs were highly represented in HCC/CRLM, while high polymorphonuclear MDSCs were detected only in HCC. Interestingly, the function of CXCR4-PB-Tregs was impaired in HCC/CRLM by the CXCR4 inhibitor R29., Conclusion: In HCC and CRLM, peripheral blood, peritumoral and tumoral tissues Tregs are highly represented and functional. Nevertheless, HCC displays a more immunosuppressive TME due to Tregs, MDSCs, intrinsic tumor features (CXCR4, CCL5, arginase) and the contest in which it develops. As CXCR4 is overexpressed in HCC/CRLM tumor/TME cells, CXCR4 inhibitors may be considered for double hit therapy in liver cancer patients., (© 2023. The Author(s).)

Liver cancer, the sixth most common cancer globally and the second-leading cause of cancer-related deaths, presents a critical public health threat. Diagnosis often occurs in advanced stages of the disease, aligning incidence with fatality rates. Given that established treatments, such as stereotactic body radiation therapy and transarterial radioembolization, face accessibility and affordability challenges, the emerging focus on cancer cell metabolism, particularly arginine (Arg) depletion, offers a promising research avenue. Arg-depleting enzymes show efficacy against Arg-auxotrophic cancers, including hepatocellular carcinoma (HCC). Thus, in this review, we explore the limitations of current therapies and highlight the potential of Arg depletion, emphasizing various Arg-hydrolyzing enzymes in clinical development., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Helicobacter pylori infection is one of the main causes of gastric cancer. thioredoxin-1 (Trx1) and arginase (RocF) expressed by H. pylori were found to be closely related to its pathogenicity. However, whether Trx1 and RocF can be used in clinical screening of highly pathogenic H. pylori and the pathogenesis of trx1 high expressing H. pylori remain still unknown., Materials and Methods: We investigated the expression level of H. pylori trx1 and H. pylori rocF in human gastric antrum tissues using reverse transcription and quantitative real-time PCR (RT-qPCR) and clarified the clinical application value of trx1 and rocF for screening highly pathogenic H. pylori. The pathogenic mechanism of Trx1 were further explored by RNA-seq of GES-1 cells co-cultured with trx1 high or low expressing H. pylori. Differentially expressed genes and signaling pathways were validated by RT-qPCR, Enzyme-linked immunosorbent assay (ELISA), western blot, immunohistochemistry and immunofluorescence. We also assessed the adherence of trx1 high and low expressing H. pylori to GES-1 cells., Results: We found that H. pylori trx1 and H. pylori rocF were more significantly expressed in the gastric cancer and peptic ulcer group than that in the gastritis group and the parallel diagnosis of H. pylori trx1 and H. pylori rocF had high sensitivity. The trx1 high expressing H. pylori had stronger adhesion ability to GES-1 cells and upregulated the interleukin (IL) 23A/nuclear factor κappaB (NF-κB)/IL17A, IL6, IL8 pathway., Conclusions: H. pylori trx1 and H. pylori rocF can be used in clinical screening of highly pathogenic H. pylori and predicting the outcome of H. pylori infection. The trx1 high expressing H. pylori has stronger adhesion capacity and promotes the development of gastric diseases by upregulating the activation of NF-κB signaling pathway., (© 2024 The Authors. Helicobacter published by John Wiley & Sons Ltd.)

Arginine, a semi-essential amino acid, is critical for cell growth. Typically, de novo synthesis of arginine is sufficient to support cellular processes, however, it becomes vital for cancer cells that are unable to synthesise arginine due to enzyme deficiencies. Targeting this need, arginine depletion with enzymes such as arginase (ARG) has emerged as a potential cancer therapeutic strategy. Studies have proposed using high dose insulin to induce a state of hypoaminoacidaemia in the body, thereby further reducing circulating arginine levels. However, the mitogenic and metabolic properties of insulin could potentially counteract the therapeutic effects of ARG. Our study examined the combined impact of insulin and ARG on breast, lung, and ovarian cell lines, focusing on cell proliferation, metabolism, apoptosis, and autophagy. Our results showed that the influence of insulin on ARG uptake varied between cell lines but failed to promote the proliferation of ARG-treated cells or aid recovery post-ARG treatment. Moreover, insulin was largely ineffective in altering ARG-induced metabolic changes and did not prevent apoptosis. In vitro, at least, these findings imply that insulin does not offer a growth or survival benefit to cancer cells being treated with ARG., (© 2024. The Author(s).)

We investigated the polarisation of CD68+ macrophages and perforin and granulysin distributions in kidney lymphocyte subsets of children with IgA vasculitis nephritis (IgAVN). Pro-inflammatory macrophage (M)1 (CD68/iNOS) or regulatory M2 (CD68/arginase-1) polarisation; spatial arrangement of macrophages and lymphocytes; and perforin and granulysin distribution in CD3+ and CD56+ cells were visulaised using double-labelled immunofluorescence. In contrast to the tubules, iNOS+ cells were more abundant than the arginase-1+ cells in the glomeruli. CD68+ macrophage numbers fluctuated in the glomeruli and were mostly labelled with iNOS. CD68+/arginase-1+ cells are abundant in the tubules. CD56+ cells, enclosed by CD68+ cells, were more abundant in the glomeruli than in the tubuli, and co-expressed NKp44. The glomerular and interstitial/intratubular CD56+ cells express perforin and granulysin, respectively. The CD3+ cells did not express perforin, while a minority expressed granulysin. Innate immunity, represented by M1 macrophages and CD56+ cells rich in perforin and granulysin, plays a pivotal role in the acute phase of IgAVN.

Background: Arginase 1 (Arg1) encodes a key enzyme that catalyzes the metabolism of arginine to ornithine and urea. In our recent study, we found that knockdown of Arg1 in the lungs of fetal mice induces apoptosis of epithelial cells and dramatically delays initiation of labor. As the most abundant internal mRNA modification, N 6 -methyladenosine (m 6 A) has been found to play important roles in lung development and cellular differentiation. However, if the knockdown of Arg1 affects the RNA m6A modification in fetal lungs remains unknown., Methods: In the current study, the RNA m6A levels and the expression of RNA m6A related enzymes were validated in 13.0 dpc fetal lungs that Arg1 was knocked down by adeno-associated virus carrying Arg1-shRNA, using western blot, immunofluorescence, and RT-qPCR., Results: No statistical differences were found in the expression of methyltransferase, demethylases, and binding proteins in the fetal lungs between AAV-shArg1-injected mice and AAV-2/9-injected mice. Besides, there is no significant change of overall RNA m6A level in fetal lungs from AAV-shArg1-injected mice, compared with that from AAV-2/9-injected mice., Conclusions: These results indicate that arginase 1 does not affect RNA m6A methylation in mouse fetal lung, and the mechanisms other than RNA m6A modification underlying the effects of Arg1 knockdown on the fetal lung development and their interaction with labor initiation need to be further explored., (© 2024 Wiley Periodicals LLC.)

L-Arginine metabolism plays a crucial role in determining the M1/M2 polarization of macrophages. The M1 macrophages express inducible nitric oxide synthase (iNOS), while the M2 macrophages express arginase 1 and metabolize arginine into nitric oxide and urea, respectively. The tumor microenvironment promotes M2 macrophage polarization and consequently switches the metabolic fate of arginine from nitric oxide towards urea production. Importantly, infiltration of M2 macrophages or tumor-associated macrophages (TAMs) has been correlated with poor prognosis of various cancer types. Melatonin is well reported to have antitumor and immunomodulatory properties. However, whether and how it impacts the polarization of TAMs has not been elucidated. Considering the crucial role of arginine metabolism in macrophage polarization, we were interested to know the fate of L-arginine in TAMs and whether it can be reinstated by melatonin or not. We used a murine model of Dalton's lymphoma and established an in vitro model of TAMs. For TAMs, we used the ascitic fluid of tumor-bearing hosts to activate the macrophages in the presence and absence of lipopolysaccharide (LPS). In these groups, L-arginine metabolism was evaluated, and then the effect of melatonin was assessed in these groups, wherein the metabolic fate of arginine as well as the expression of iNOS and arginase 1 were checked. Furthermore, in the in vivo system of the tumor-bearing host, the effect of melatonin was assessed. The in vitro model of TAMs showed a Th2 cytokine profile, reduced phagocytic activity, and increased wound healing ability. Upon investigating arginine metabolism, we observed high urea levels with increased activity and expression of arginase 1 in TAMs. Furthermore, we observed reduced levels of LPS-induced nitric oxide in TAMs; however, their iNOS expression was comparable. With melatonin treatment, urea level decreased significantly, while the reduction in nitric oxide level was not as significant as observed in its absence in TAMs. Also, melatonin significantly reduced arginase activity and expression at the transcriptional and translational levels, while iNOS expression was affected only at the translational level. This effect was further investigated in the in vivo system, wherein melatonin treatment reversed the metabolic fate of arginine, from urea towards nitric oxide, within the tumor microenvironment. This effect was further correlated with pro-apoptotic tumor cell death in the in vivo system. Our results reinforced the immunomodulatory role of melatonin and offered a strong prospect for activating the anti-tumor immune response in cancer conditions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Triptolide (TPT) is widely used in the treatment of rheumatoid arthritis (RA). However, its regulatory mechanisms are not fully understood. This study demonstrated that Myeloid-derived suppressor cells (MDSCs) were expanded in both RA patients and arthritic mice. The frequency of MDSCs was correlated with RA disease severity and T helper 17 (Th17) responses. MDSCs from RA patients promoted the polarization of Th17 cells in vitro, which could be substantially attenuated by blocking arginase-1 (Arg-1). TPT inhibited the differentiation of MDSCs, particularly the monocytic MDSCs (M-MDSCs) subsets, as well as the expression of Arg-1 in a dose dependent manner. Alongside, TPT treatment reduced the potential of MDSCs to promote the polarization of IL-17 + T cell in vitro. Consistently, TPT immunotherapy alleviated adjuvant-induced arthritis (AIA) in a mice model, and reduced the frequency of MDSCs, M-MDSCs and IL-17 + T cells simultaneously. The presented data suggest a pathogenic role of MDSCs in RA and may function as a novel and effective therapeutic target for TPT in RA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: L-arginase, is a powerful anticancer that hydrolyzes L-arginine to L-ornithine and urea. This enzyme is widely distributed and expressed in organisms like plants, fungi, however very scarce from bacteria. Our study is based on isolating, purifying, and screening the marine bacteria that can produce arginase., Results: The highest arginase producing bacteria will be identified by using microbiological and molecular biology methods as Bacillus licheniformis OF2. Characterization of arginase is the objective of this study. The activity of enzyme was screened, and estimated beside partial sequencing of arginase gene was analyzed. In silico homology modeling was applied to generate the protein's 3D structure, and COACH and COFACTOR were applied to determine the protein's binding sites and biological annotations based on the I-TASSER structure prediction. The purified enzyme was undergone an in vitro anticancer test., Conclusions: L-arginase demonstrated more strong anti-cancer cells with an IC50 of 21.4 ug/ml in a dose-dependent manner. L-arginase underwent another investigation for its impact on the caspase 7 and BCL2 family of proteins (BCL2, Bax, and Bax/Bcl2). Through cell arrest in the G1/S phase, L-arginase signals the apoptotic cascade, which is supported by a flow cytometry analysis of cell cycle phases., (© 2024. The Author(s).)

Three neo-clerodane diterpenoids, including two new tinocordifoliols A (1) and B (2) and one known tinopanoid R (3), were isolated from the ethyl acetate-soluble fraction of the 70% ethanol extract of Tinospora cordifolia stems. The structures were elucidated by various spectroscopic methods, including one dimensional (1D) and 2D-NMR, high resolution-electrospray ionization (HR-ESI)-MS, and electronic circular dichroism (ECD) data. The T. cordifolia extract and all isolated compounds 1-3 possessed arginase I inhibitory activities. Among them, 3 exhibited moderate competitive inhibition of human arginase I (IC 50  = 61.9 µM). Furthermore, docking studies revealed that the presence of a β-substituted furan in 3 may play a key role in the arginase I inhibitory activities.

Introduction: The muscarinic M3 receptor antagonist, tiotropium, has a bronchodilatory effect on asthma patients. Additionally, tiotropium inhibits allergic airway inflammation and remodeling in a murine asthma model. However, the underlying mechanisms of this M3 receptor antagonist remain unclear. Therefore, we investigated the effect of muscarinic M3 receptor blockage on M2 macrophage development during allergic airway inflammation., Methods: BALB/c mice were sensitized and challenged with ovalbumin to develop a murine model of allergic airway inflammation mimicking human atopic asthma. During the challenge phase, mice were treated with or without tiotropium. Lung cells were isolated 24 h after the last treatment and gated using CD68-positive cells. Relm-α and Arginase-1 (Arg1) (M2 macrophage markers) expression was determined by flow cytometry. Mouse bone marrow mononuclear cell-derived macrophages (mBMMacs) and human peripheral blood mononuclear cells (PBMCs)-derived macrophages were stimulated with IL-4 and treated with a muscarinic M3 receptor antagonist in vitro., Results: The total cells, eosinophils, and IL-5 and IL-13 levels in BAL fluids were markedly decreased in the asthma group treated with tiotropium compared to that in the untreated asthma group. The Relm-α and Arg1 expression in macrophages was reduced considerably in the asthma group treated with tiotropium compared to that in the untreated asthma group, suggesting that the development of M2 macrophages was inhibited by muscarinic M3 receptor blockage. Additionally, muscarinic M3 receptor blockage in vitro significantly inhibited M2 macrophage development in both mBMMacs- and PBMCs-derived macrophages., Conclusions: Muscarinic M3 receptor blockage inhibits M2 macrophage development and prevents allergic airway inflammation. Moreover, muscarinic M3 receptors might be involved in the differentiation of immature macrophages into M2 macrophages., (© 2024 S. Karger AG, Basel.)

Background & Aims: Restoring hepatic and peripheral insulin sensitivity is critical to prevent or reverse metabolic syndrome and type 2 diabetes. Glucose homeostasis comprises in part the complex regulation of hepatic glucose production and insulin-mediated glucose uptake and oxidation in peripheral tissues. We previously identified hepatocyte arginase 2 (Arg2) as an inducible ureahydrolase that improves glucose homeostasis and enhances glucose oxidation in multiple obese, insulin-resistant models. We therefore examined structure-function determinants through which hepatocyte Arg2 governs systemic insulin action and glucose oxidation., Methods: To do this, we generated mice expressing wild-type murine Arg2, enzymatically inactive Arg2 (Arg2 H160F ) and Arg2 lacking its putative mitochondrial targeting sequence (Arg2 Δ1-22 ). We expressed these hepatocyte-specific constructs in obese, diabetic (db/db) mice and performed genetic complementation analyses in hepatocyte-specific Arg2-deficent (Arg2 LKO ) mice., Results: We show that Arg2 attenuates hepatic steatosis, independent of mitochondrial localization or ureahydrolase activity, and that enzymatic arginase activity is dispensable for Arg2 to augment total body energy expenditure. In contrast, mitochondrial localization and ureahydrolase activity were required for Arg2-mediated reductions in fasting glucose and insulin resistance indices. Mechanistically, Arg2 Δ1-22 and Arg2 H160F failed to suppress glucose appearance during hyperinsulinemic-euglycemic clamping. Quantification of heavy-isotope-labeled glucose oxidation further revealed that mistargeting or ablating Arg2 enzymatic function abrogates Arg2-induced peripheral glucose oxidation., Conclusion: We conclude that the metabolic effects of Arg2 extend beyond its enzymatic activity, yet hepatocyte mitochondrial ureahydrolysis drives hepatic and peripheral oxidative metabolism. The data define a structure-based mechanism mediating hepatocyte Arg2 function and nominate hepatocyte mitochondrial ureahydrolysis as a key determinant of glucose oxidative capacity in mammals., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Amino acid L-arginine (Arg), usually presented in food products and biological liquids, can serve both as a useful indicator of food quality and an important biomarker in medicine. The biosensors based on Arg-selective enzymes are the most promising devices for Arg assay. In this research, three types of amperometric biosensors have been fabricated. They exploit arginine oxidase (ArgO), recombinant arginase I (ARG)/urease, and arginine deiminase (ADI) coupled with the ammonium-chelating redox-active nanoparticles. Cadmium-copper nanoparticles (nCdCu) as the most effective nanochelators were used for the development of ammonium chemosensors and enzyme-coupled Arg biosensors. The fabricated enzyme/nCdCu-containing bioelectrodes show wide linear ranges (up to 200 µM), satisfactory storage stabilities (14 days), and high sensitivities (A⋅M -1 ⋅m -2 ) to Arg: 1650, 1700, and 4500 for ADI-, ArgO- and ARG/urease-based sensors, respectively. All biosensors have been exploited to estimate Arg content in commercial juices. The obtained data correlate well with the values obtained by the reference method. A hypothetic scheme for mechanism of action of ammonium nanochelators in electron transfer reaction on the arginine-sensing electrodes has been proposed., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Objective. The study was performed to elucidate whether nicotinamide (NAm) can attenuate the diabetes-induced liver damage by correction of ammonia detoxifying function and disbalance of NAD-dependent processes in diabetic rats. Methods. After four weeks of streptozotocin-induced diabetes, Wistar male rats were treated for two weeks with or without NAm. Urea concentration, arginase, and glutamine synthetase activities, NAD+ levels, and NAD+/NADH ratio were measured in cytosolic liver extracts. Expression of parp-1 gene in the liver was estimated by quantitative polymerase chain reaction and PARP-1 cleavage evaluated by Western blotting. Results. Despite the blood plasma lipid peroxidation products in diabetic rats were increased by 60%, the activity of superoxide dismutase (SOD) was reduced. NAm attenuated the oxidative stress, but did not affect the enzyme activity in diabetic rats. In liver of the diabetic rats, urea concentration and arginase activity were significantly higher than in the controls. The glutamine synthetase activity was decreased. Decline in NAD+ level and cytosolic NAD+/NADH ratio in the liver of diabetic rats was observed. Western blot analysis demonstrated a significant up-regulation of PARP-1 expression accompanied by the enzyme cleavage in the diabetic rat liver. However, no correlation was seen between mRNA expression of parp-1 gene and PARP-1 protein in the liver of diabetic rats. NAm markedly attenuated PARP-1 cleavage induced by diabetes, but did not affect the parp-1 gene expression. Conclusions. NAm counteracts diabetes-induced impairments in the rat liver through improvement of its detoxifying function, partial restoration of oxidative stress, NAD+ level, normalization of redox state of free cytosolic NAD+/NADH-couples, and prevention of PARP-1 cleavage., (© 2023 Tamara Kuchmerovska et al., published by Sciendo.)

Background: Interferon (IFN)-γ and interleukin (IL)-4 are considered to be important factors to regulate immune responses. Although the effects of IFN-γ or IL-4 on macrophage functions are well established, their cooperative action is not fully understood., Objective: Inducible nitric oxide synthase (iNOS) or arginase (Arg)-1 is a representative marker of M1 or M2 macrophages and plays a role in the acceleration or suppression of inflammatory responses. In the present study, we examined the effect of simultaneous treatment with IFN-γ and IL-4 on macrophage expression of iNOS and Arg-1 using the murine macrophage cell line RAW264.7., Methods: Protein production and mRNA expression of iNOS and Arg-1 were measured using immunoblotting and reverse transcription-polymerase chain reaction. Cell surface expression of CD86 and programmed death ligand (PD-L) 2 was analyzed using flow cytometry., Results: IFN-γ or IL-4 increased iNOS or Arg-1 protein production, respectively. Of note, IL-4 combined with IFN-γ synergistically increased Arg-1 protein production, whereas IL-4 inhibited IFN-γ-induced iNOS production. This phenomenon was consistent with the mRNA levels. In addition, IL-4 combined with IFN-γ synergistically increased cell surface expression of PD-L2, which is involved in T cell suppression, whereas IL-4 completely inhibited IFN-γ-induced expression of CD86, which is responsible for T cell activation., Conclusions: In the present study, we found the synergy of IFN-γ and IL-4 in Arg-1 and PD-L2 expression. Thus, macrophages highly expressing Arg-1 and PD-L2 may be induced by both IFN-γ and IL-4 at the inflammatory site, and might play a role in the regulation of inflammatory immune responses.

Introduction: The implication of arginase enzyme in Human Papillomavirus (HPV) infections has not been clearly elucidated. The present study investigates whether HPV infection is correlated with changes in plasmatic arginase activity and cervical ARG1 and ARG2 mRNA expression among infected women negative for intraepithelial lesions (NIL)., Materiel and Methods: The present study included 300 women. The plasmatic arginase activity was evaluated by a colorimetric assay. Cervical HPV was detected by real-time PCR. The circulating viral load and ARG1 and ARG2 mRNA expression quantification were performed by quantitative real-time PCR., Results: A significant increase in plasma arginase activity and ARG1 and ARG2 mRNA expression levels in cervical cells was observed among HPV-positive women compared to the HPV-negative group. The highest levels were significantly associated with oncogenic HPV, and increased arginase activity was associated with a high HPV circulating viral load. Moreover, the highest levels of arginase activity were observed in oncogenic HPV-positive inflammatory smears., Discussion: These data suggest that HPV could modulate arginase activity and expression, which may restrict arginine bioavailability and inhibit this amino acid's antiviral properties., Conclusion: Our findings revealed that arginase activity and isoform gene expression were upregulated in women with HPV infection, particularly the oncogenic HPV types.