Expression Of Arginase Research Articles

IL-9 responsive macrophages utilize Arginase 1 to enhance lung tumor growth

Abstract In cancer, the immunosuppressive function of myeloid cells that support tumor progression is controlled by secreted factors in the tumor microenvironment. In the tumor microenvironment, arginine and arginine-derived metabolites have been demonstrated to be crucial factors in tumor development. Within macrophages, arginine metabolism influences the polarization of macrophages and therefore, tumor growth by eliciting an anti-tumoral or pro-tumoral phenotype. Interleukin 9 (IL-9) is a pleiotropic cytokine that signals through the IL-9 receptor (IL-9R) and can function as a positive or negative regulator in tumor immunity. Recently, our lab has demonstrated that IL-9 signaling promotes tumor progression in the lung by expanding pulmonary interstitial macrophage populations and inducing Arginase 1 (ARG1), an enzyme associated with pro-tumoral macrophage function, activity. However, the mechanism by which IL-9R/ARG1+ interstitial macrophages promote tumor development remains unknown. Here, using a B16F10 model of metastatic lung cancer, we demonstrate that knockdown of ARG1 using macrophage targeting Arg1siRNA containing nanoparticles results in altered pulmonary T-cell and macrophage proportions. Moreover, attenuation of IL-9 signaling and ARG1 expression in macrophages impacts arginine and arginine-derived metabolite concentration in lung tissue and BAL fluid which correlates with decreases in CD4+ T Cell exhaustion marker expression and a concomitant reduction in PDL1 expression on pulmonary interstitial macrophages in tumor-bearing mice. Thus, our work suggests that the IL-9R/ARG1 axis in macrophages is sufficient to alter arginine in the tumor microenvironment and promote tumor growth.

Assessing the Role of the VCAM1-VLA4 Interaction in Macrophage Polarization in Pulmonary Metastatic Osteosarcoma

Abstract Macrophages are key members of the innate immune system involved in phagocytosis, antigen presentation and other immunological functions. Macrophages are also important players in response to tumor. Their polarization states determine the role that they play in the tumor microenvironment (TME) and are generally regarded as M1-like and M2-like tumor associated macrophages (TAMs). Subsequently, the TME influences how macrophages function in that environment. Osteosarcoma is an aggressive solid tumor and about 20% of patients present with lung metastasis at the time of diagnosis. Pulmonary metastatic osteosarcoma has a low 5-year survival rate of less than 20%. The ability for osteosarcoma to metastasize to the lungs is due, in part, by the expression of Vascular Cell Adhesion Molecule 1 (VCAM1) on its surface. However, it is not well-known how expression of this protein contributes to tumor metastasis. We speculate that the binding interaction between VCAM1 and its integrin α4β1 (VLA4) has some role in this process. Recently, our lab has obtained preliminary data suggesting one of the methods osteosarcomas use to shape macrophages into a pro-tumor (M2-like) phenotype is through the interaction between VCAM1 on its surface and the VLA4 integrin on macrophages. Our data shows that this interaction upregulates expression of the enzyme Arginase 1, (Arg1) a well-accepted marker of M2-polarized macrophages. We speculate that this phenomenon may be, in part, regulated by the protein, suppressor of cytokine signaling 1 (SOCS1), as it inhibits the phosphorylation of the transcription factor, signal transducer and activator of transcription 1 (STAT1); thus, allowing STAT3 to phosphorylate and upregulate M2-associated genes such as Arg1. St Baldricks Foundation, Keira Kilbane Foundation, Steven G. AYA Cancer Research Fund, Theresa G. & Stuart F. Kline Family Foundation

Engineering amino acid uptake or catabolism promotes CAR T-cell adaption to the tumor environment.

Cancer cells take up amino acids from the extracellular space to drive cell proliferation and viability. Similar mechanisms are applied by immune cells, resulting in the competition between conventional T cells, or indeed chimeric antigen receptor (CAR) T cells and tumor cells, for the limited availability of amino acids within the environment. We demonstrate that T cells can be re-engineered to express SLC7A5 or SLC7A11 transmembrane amino acid transporters alongside CARs. Transporter modifications increase CAR T-cell proliferation under low tryptophan or cystine conditions with no loss of CAR cytotoxicity or increased exhaustion. Transcriptomic and phenotypic analysis reveals that downstream, SLC7A5/SLC7A11-modified CAR T cells upregulate intracellular arginase expression and activity. In turn, we engineer and phenotype a further generation of CAR T cells that express functional arginase 1/arginase 2 enzymes and have enhanced CAR T-cell proliferation and antitumor activity. Thus, CAR T cells can be adapted to the amino acid metabolic microenvironment of cancer, a hitherto recognized but unaddressed barrier for successful CAR T-cell therapy.

Arginase Inhibition Mitigates Bortezomib-Exacerbated Cardiotoxicity in Multiple Myeloma.

Multiple myeloma (MM) is associated with increased cardiovascular morbidity and mortality, while MM therapies also result in adverse cardiac effects. Endothelial dysfunction and impaired nitric oxide (NO) pathway is their possible mediator. Since MM is associated with increased arginase expression, resulting in the consumption of ʟ-arginine, precursor for NO synthesis, our aim was to test if cardiotoxicity mediated by MM and MM therapeutic, bortezomib (a proteasome inhibitor), can be ameliorated by an arginase inhibitor through improved endothelial function. We used a mouse Vĸ*MYC model of non-light chain MM. Cardiac function was assessed by echocardiography. MM resulted in progressive left ventricular (LV) systolic dysfunction, and bortezomib exacerbated this effect, leading to significant impairment of LV performance. An arginase inhibitor, OAT-1746, protected the heart against bortezomib- or MM-induced toxicity but did not completely prevent the effects of the MM+bortezomib combination. MM was associated with improved endothelial function (assessed as NO production) vs. healthy controls, while bortezomib did not affect it. OAT-1746 improved endothelial function only in healthy mice. NO plasma concentration was increased by OAT-1746 but was not affected by MM or bortezomib. Bortezomib exacerbates MM-mediated LV systolic dysfunction in a mouse model of MM, while an arginase inhibitor partially prevents it. Endothelium does not mediate either these adverse or beneficial effects. This suggests that proteasome inhibitors should be used with caution in patients with advanced myeloma, where the summation of cardiotoxicity could be expected. Therapies aimed at the NO pathway, in particular arginase inhibitors, could offer promise in the prevention/treatment of cardiotoxicity in MM.

Protein Phosphatase 2A Regulates Phenotypic and Metabolic Alteration of Microglia Cells in HFD-Associated Vascular Dementia Mice via TNF-α/Arg-1 Axis.

Protein phosphatase 2A (PP2A), the activity of which is dictated by the composition of its regulatory subunit, is strongly related to the progression of neurodegenerative disease. The potential role of PP2A on the phenotypic transition of microglial cells under obese conditions is poorly explored. An understanding of the role of PP2A and identification of regulatory subunits contributing to microglial phenotypic transitions in obese condition may serve as a therapeutic target for obesity-associated neurodegeneration. C57BL/6 mice were exposed to obese-associated vascular dementia conditions by performing unilateral common carotid artery occlusion on obese mice of microglial polarization and PP2A activity using flow cytometry, real-time PCR, western blotting, and immunoprecipitation enzymatic assay, followed identifications of PP2A regulatory subunits using LCMS and RT-PCR. Chronic HFD feeding significantly increased the populations of infiltrated macrophages, showing a high percentage of CD86+ in VaD mice, and the expression of pro-inflammatory cytokines, and we observed that PP2A modulates metabolic reprogramming of microglia by regulating OXPHOS/ECAR activity. Using Co-IP and LCMS, we identified the six specific regulatory subunits, namely PPP2R2A, PPP2R2D, PPP2R5B, PPP2R5C, PPP2R5D, and PPP2R5E, that are associated with microglial-activation during obesity-associated-VaD. Interestingly, pharmacological up-regulation of PP2A more significantly suppressed the expression of TNF-alpha than other pro-inflammatory-cytokines and increased the expression of Arginase-1, suggesting that PP2A modulates microglial-phenotypic transitions through TNF-α/Arg-1 axis.Our present findings demonstrate microglial polarization in HFD associated with VaD, and point towards atherapeutic target by providing specific PP2A regulatory-subunits implicated in microglial activation during obesity-related-vascular-dementia.

Abstract 2470: ARG1 is potential prognostic biomarker for development of distant metastatic endometrial cancer in mice with Pten deficiency

Abstract Endometrial cancer is the most common gynecologic malignancy. The most common histological type is endometrioid endometrial cancer (EEC). While the majority of patients present with early-stage and low-grade EEC 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 EEC is a critical barrier. We have developed a genetically engineered mouse model for metastatic EEC that implicates coexistent Pten and Mig-6 mutations in EEC. Pten mutation in the uterus is not sufficient for distant metastasis, but mice with concurrent ablation of Mig-6 and Pten develop distant metastasis. 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 including ovarian carcinoma, colorectal cancer, and neuroblastoma. In the present study, ARG1 expression was evaluated with immunohistochemistry in endometrial hyperplasia and cancer of mice with Pten mutation as well as Pten and Mig-6 double mutations. Our immunostaining analysis revealed that the expression of ARG1 in early stage of EEC from mice deficient in Mig-6 and Pten mutations significantly increased compared to Pten mutation in the uterus. High levels of ARG1 are associated with distant metastatic endometrial cancer. The results demonstrate that a high level of ARG1 is associated with poor prognosis in association with EEC of mouse. ARG1 has the potential to identify patients that require additional treatment at an early stage of endometrial cancer. Citation Format: Jae-Wook Jeong, Dinh Tran, Valery Rozen, Tae Hoon Kim, Jung-Yoon Yoo. ARG1 is potential prognostic biomarker for development of distant metastatic endometrial cancer in mice with Pten deficiency [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2470.

Abstract 4128: AJ17 potentiates agonist CD40 antibody efficacy and attenuates agonist CD40 induced PD-L1 expression and associated toxicity in murine tumor models

Abstract Agonist CD40 antibody (αCD40) has shown excellent anti-tumor efficacy in both pre and early clinical studies. However, in clinics, αCD40 has failed to prove its potential as αCD40 is associated with dose-limiting toxicity due to cytokine release syndrome (CRS), grade 3 to 4 hematological and liver toxicities. In addition, αCD40 induces immune checkpoint proteins (PD-L1, CTLA-4) which makes the tumor microenvironment (TME) immunosuppressive. In this context, this study investigates the therapeutic efficacy of a novel combination of αCD40 and AJ17, a small molecule inhibitor of receptor tyrosine kinase. Combination treatment showed a significant delay in the tumor growth and improved overall survival in mice bearing B16-F10 melanoma and 4T1 orthotopic tumor by increasing the population of CD8+ T cells and lowering the expression of PD-L1, Foxp3+, and arginase in both tumor and spleen. Most interestingly, AJ17 lowered the in vivo toxicity associated with αCD40 monotherapy by lowering the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and IL-6 in serum. In conclusion, this combination can be further explored in clinics to improve the in vivo anti-tumor efficacy of αCD40 while lowering the associated toxicity. Citation Format: Vidit Gaur, Anjali Barnwal, Bushra Ateeq, Jayanta Bhattacharyya. AJ17 potentiates agonist CD40 antibody efficacy and attenuates agonist CD40 induced PD-L1 expression and associated toxicity in murine tumor models. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4128.

Abstract 4427: Cucurbitacin B: A promising drug candidate for targeting tumor immunosuppressive cells

Abstract Immunotherapy has emerged as a major breakthrough in cancer treatment. However, it showed only a marginal response in pancreatic and liver cancers. Thus, novel strategies are highly desirable to take full advantage of immunotherapy in the treatment of these cancers. One of the critical factors that influence the efficacy of immunotherapy is the increased infiltration of myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAM) into tumors that alter the immune landscape and serve as facilitators of tumor proliferation, metastatic growth, and immunotherapy resistance. Thus, we believe that selecting a potent molecule that has the ability to suppress the function or revert the phenotypes of TAM and MDSCs will have a more significant impact in enhancing tumor immunotherapy response. Cucurbitacin B (Cuc B) is a potent inhibitor of Stat3, CSF-1R, and PI3Kγ and has shown its chemopreventive and therapeutic effects against various cancers but is limitedly explored for its application in modulating tumor immune response. In this study, we investigated the molecular effects and underlying molecular mechanisms of Cuc B on TAM and MDSCs. Cuc B significantly (P<0.01) decreased the expression of M2 markers (Arginase I, YM1 FIZZ1, PPARγ and TGFβ in M2 polarized BMDMs and increased M1 markers (NOS2, IL-6, and CD11C) compared to IL-4 alone treatment group. It has been demonstrated that TAMs secrete PDL-1 which neutralizes the function of T-cells. Cuc B treatment significantly (P<0.001) decreased PDL-1 expression in IL-4-treated RAW264.7 cells. Surprisingly, we observed that Cuc B treatment abolished the protein levels of PI3Kγ in IL-4 treated macrophages as determined by confocal microscopy and Western blot analysis. Cuc B treatment of bone marrow-derived MDSCs significantly (P<0.01) decreased the expression of Arginase-1, IL-10, PDL-1, and Stat3. We observed that IL-4-treated BMDMs inhibited phagocytic capacity which was significantly restored upon Cuc B treatment. We observed that Cuc B is a more potent molecule than a pharmacological inhibitor of PI3Kγ (IPI-549) in suppressing key signaling components of TAM and MDSCs. We are performing in vivo study to investigate Cuc B potential to enhance checkpoint blockade immunotherapy response in clinically relevant mouse models of cancer. These results suggest that Cuc B is a novel therapeutic agent which has the potential to suppress or revert TAMs and MDSCs phenotypes. Cuc B may be used as an adjuvant drug molecule in combination with PD1 or CTLA-4 antibodies for improving immunotherapy response against less responsive tumors. Citation Format: Emmanuel B. Anning, Mudassier Ahmad, Sahir Alvi, Carlos Parez, Mehdi Chaib, Divyam Bansal, Dae Kim, Subhash Chauhan, Taha Merghoub, Bilal Hafeez. Cucurbitacin B: A promising drug candidate for targeting tumor immunosuppressive cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4427.

Neutralization of NET-associated human ARG1 enhances cancer immunotherapy.

Myeloid cells can restrain antitumor immunity by metabolic pathways, such as the degradation of l-arginine, whose concentrations are regulated by the arginase 1 (ARG1) enzyme. Results from preclinical studies indicate the important role of arginine metabolism in pancreatic ductal adenocarcinoma (PDAC) progression, suggesting a potential for clinical application; however, divergent evolution in ARG1 expression and function in rodents and humans has restricted clinical translation. To overcome this dichotomy, here, we show that neutrophil extracellular traps (NETs), released by spontaneously activated neutrophils isolated from patients with PDAC, create a microdomain where cathepsin S (CTSS) cleaves human (h)ARG1 into different molecular forms endowed with enhanced enzymatic activity at physiological pH. NET-associated hARG1 suppresses T lymphocytes whose proliferation is restored by either adding a hARG1-specific monoclonal antibody (mAb) or preventing CTSS-mediated cleavage, whereas small-molecule inhibitors are not effective. We show that ARG1 blockade, combined with immune checkpoint inhibitors, can restore CD8+ T cell function in ex vivo PDAC tumors. Furthermore, anti-hARG1 mAbs increase the frequency of adoptively transferred tumor-specific CD8+ T cells in tumor and enhance the effectiveness of immune checkpoint therapy in humanized mice. Thus, this study shows that extracellular ARG1, released by activated myeloid cells, localizes in NETs, where it interacts with CTSS that in turn cleaves ARG1, producing major molecular forms endowed with different enzymatic activity at physiological pH. Once exocytosed, ARG1 activity can be targeted by mAbs, which bear potential for clinical application for the treatment of PDAC and require further exploration.

Pharmacological blockade of HDAC3 accelerates diabetic wound healing by regulating macrophage activation

AimsHere, we report the effect of histone deacetylase 3 (HDAC3) inhibition associated with macrophage activation, IL-1β expression, angiogenesis and wound healing in diabetic mice. Main methodsTo determine the expression of HDAC3 in diabetic mice wounds, hyperglycemia was induced in C57BL/6 mice with streptozotocin followed by induction of 6 mm wounds. To understand the effect of HDAC3 selective inhibitor, BG45, wound tissues were isolated for analysing M1/M2 markers expression, immune cells infiltration, angiogenesis and healing factors expression. CD11b+F4/80+ cells were sorted from the wound tissues and analysed for the expression of M1/M2 markers using RT-qPCR and flow cytometer. In cell based assays, HDAC3 expression was measured in macrophages stimulated with high glucose (HG) plus LPS. Macrophages treated with BG45 and HG + LPS were analysed for the expression of pro-IL-1β, mature IL-1β, oxidative stress and pro-inflammatory (M1) and anti-inflammatory (M2) factors. Key findingsHDAC3 was found to be upregulated in impaired diabetic mice wounds and in macrophages stimulated with HG + LPS. Topical application of BG45 loaded gel accelerated the wound healing in diabetic mice and was evident by improved expression of Collagen-1A, IL-10, TGF-β, and angiogenesis (CD31, VEGF). BG45 treatment decreased the expression of IL-1β, TNF-α, and IL-6 (M1 phenotype), reduced oxidative stress and promoted the expression of Arginase-1 and YM1/2 (M2 phenotype) in macrophages treated with HG + LPS. BG45 also improved the expression of CD11b+F4/80+CD206+ cells in wound tissues and reduced expression of inflammatory markers. SignificanceHDAC3 is upregulated in diabetic mice wounds and HDAC3 selective inhibitor promotes the wound healing by regulating macrophage activation, angiogenesis and IL-1β.

Tamoxifen Modulates the Immune Landscape of the Tumour Microenvironment: The Paired Siglec-5/14 Checkpoint in Anti-Tumour Immunity in an In Vitro Model of Breast Cancer.

Since the role of sialome-Siglec axis has been described as a regulatory checkpoint of immune homeostasis, the promotion of stimulatory or inhibitory Siglec-related mechanisms is crucial in cancer progression and therapy. Here, we investigated the effect of tamoxifen on the sialic acid-Siglec interplay and its significance in immune conversion in breast cancer. To mimic the tumour microenvironment, we used oestrogen-dependent or oestrogen-independent breast cancer cells/THP-1 monocytes transwell co-cultures exposed to tamoxifen and/or β-estradiol. We found changes in the cytokine profiles accompanied by immune phenotype switching, as measured by the expression of arginase-1. The immunomodulatory effects of tamoxifen in THP-1 cells occurred with the altered SIGLEC5 and SIGLEC14 genes and the expression of their products, as confirmed by RT-PCR and flow cytometry. Additionally, exposure to tamoxifen increased the binding of Siglec-5 and Siglec-14 fusion proteins to breast cancer cells; however, these effects appeared to be unassociated with oestrogen dependency. Our results suggest that tamoxifen-induced alterations in the immune activity of breast cancer reflect a crosstalk between the Siglec-expressing cells and the tumour's sialome. Given the distribution of Siglec-5/14, the expression profile of inhibitory and activatory Siglecs in breast cancer patients may be useful in the verification of therapeutic strategies and predicting the tumour's behaviour and the patient's overall survival.

HIF-1α-Overexpressing Mesenchymal Stem Cells Attenuate Colitis by Regulating M1-like Macrophages Polarization toward M2-like Macrophages

A modified mesenchymal stem cell (MSC) transplantation is a highly effective and precise treatment for inflammatory bowel disease (IBD), with a significant curative effect. Thus, we aim to examine the efficacy of hypoxia-inducible factor (HIF)-1α-overexpressing MSC (HIF-MSC) transplantation in experimental colitis and investigate the immunity regulation mechanisms of HIF-MSC through macrophages. A chronic experimental colitis mouse model was established using 2,4,6-trinitrobenzene sulfonic acid. HIF-MSC transplantation significantly attenuated colitis in weight loss rate, disease activity index (DAI), colon length, and pathology score and effectively rebuilt the local and systemic immune balance. Macrophage depletion significantly impaired the benefits of HIF-MSCs on mice with colitis. Immunofluorescence analysis revealed that HIF-MSCs significantly decreased the number of M1-like macrophages and increased the number of M2-like macrophages in colon tissues. In vitro, co-culturing with HIF-MSCs significantly decreased the expression of pro-inflammatory factors, C-C chemokine receptor 7 (CCR-7), and inducible nitric oxide synthase (INOS) and increased the expression of anti-inflammatory factors and arginase I (Arg-1) in induced M1-like macrophages. Flow cytometry revealed that co-culturing with HIF-MSCs led to a decrease in the proportions of M1-like macrophages and an increase in that of M2-like macrophages. HIF-MSCs treatment notably upregulated the expression of downstream molecular targets of phosphatidylinositol 3-kinase-γ (PI3K-γ), including HIF-1α and p-AKT/AKT in the colon tissue. A selected PI3K-γ inhibitor, IPI549, attenuated these effects, as well as the effect on M2-like macrophage polarization and inflammatory cytokines in colitis mice. In vitro, HIF-MSCs notably upregulated the expression of C/EBPβ and AKT1/AKT2, and PI3K-γ inhibition blocked this effect. Modified MSCs stably overexpressed HIF-1α, which effectively regulated macrophage polarization through PI3K-γ. HIF-MSC transplantation may be a potentially effective precision therapy for IBD.

Inhibiting efferocytosis reverses macrophage-mediated immunosuppression in the leukemia microenvironment.

Previous studies show that the spleen and bone marrow can serve as leukemia microenvironments in which macrophages play a significant role in immune evasion and chemoresistance. We hypothesized that the macrophage driven tolerogenic process of efferocytosis is a major contributor to the immunosuppressive leukemia microenvironment and that this was driven by aberrant phosphatidylserine expression from cell turnover and cell membrane dysregulation. Since MerTK is the prototypic efferocytosis receptor, we assessed whether the MerTK inhibitor MRX2843, which is currently in clinical trials, would reverse immune evasion and enhance immune-mediated clearance of leukemia cells. We found that inhibition of MerTK decreased leukemia-associated macrophage expression of M2 markers PD-L1, PD-L2, Tim-3, CD163 and Arginase-1 compared to vehicle-treated controls. Additionally, MerTK inhibition led to M1 macrophage repolarization including elevated CD86 and HLA-DR expression, and increased production of T cell activating cytokines, including IFN-β, IL-18, and IL-1β through activation of NF-κB. Collectively, this macrophage repolarization had downstream effects on T cells within the leukemia microenvironment, including decreased PD-1+Tim-3+ and LAG3+ checkpoint expression, and increased CD69+CD107a+ expression. These results demonstrate that MerTK inhibition using MRX2843 altered the leukemia microenvironment from tumor-permissive toward immune responsiveness to leukemia and culminated in improved immune-mediated clearance of AML.

Mollugin ameliorates murine allergic airway inflammation by inhibiting Th2 response and M2 macrophage activation

Mollugin, isolated from Rubia cordifolia L, is a pharmacological compound with anti-inflammatory activity. This study aimed to investigate whether mollugin protects mice against shrimp tropomyosin (ST)-induced allergic airway inflammation. Mice were sensitized with ST combined with Al(OH)3 administered intraperitoneally (i.p.) once weekly for 3 wk followed by ST challenge for 5 d. Mice were i.p.-administered daily with mollugin for 7 d. Results showed that mollugin attenuated ST-induced infiltration of eosinophils and epithelial mucus secretion in the lung tissues and suppressed lung eosinophil peroxidase activity. Additionally, mollugin lowered the Th2 cytokine, IL-4 and IL-5, production and downregulated the mRNA levels of Il-4, Il-5, Il-13, eotaxin, Ccl-17, Muc5ac, arginase-1, Ym-1, and Fizz-1 in the lung tissues. Network pharmacology was employed to predict core targets, and the molecular docking approach was used to verify the compound targets. The results of the molecular docking study of mollugin into p38 MAPK or poly(ADP-ribose) polymerase 1 (PARP1) binding sites revealed that its mechanism was possibly similar to that of SB203580 (a p38 MAPK inhibitor) or olaparib (a PARP1 inhibitor). Immunohistochemistry analysis revealed that mollugin mitigated ST-induced elevation of arginase-1 expression and macrophage levels in the lungs and bronchoalveolar lavage fluid, respectively. Furthermore, arginase-1 mRNA level and phosphorylation of p38 MAPK were inhibited in IL-4-stimulated peritoneal macrophages. In ST-stimulated mouse primary splenocytes, mollugin notably inhibited IL-4 and IL-5 production and downregulated PARP1 and PAR protein expression. According to our findings, mollugin ameliorated allergic airway inflammation by inhibiting Th2 response and macrophage polarization.

Arginase 1 is a key driver of immune suppression in pancreatic cancer.

An extensive fibroinflammatory stroma rich in macrophages is a hallmark of pancreatic cancer. In this disease, it is well appreciated that macrophages are immunosuppressive and contribute to the poor response to immunotherapy; however, the mechanisms of immune suppression are complex and not fully understood. Immunosuppressive macrophages are classically defined by the expression of the enzyme Arginase 1 (ARG1), which we demonstrated is potently expressed in pancreatic tumor-associated macrophages from both human patients and mouse models. While routinely used as a polarization marker, ARG1 also catabolizes arginine, an amino acid required for T cell activation and proliferation. To investigate this metabolic function, we used a genetic and a pharmacologic approach to target Arg1 in pancreatic cancer. Genetic inactivation of Arg1 in macrophages, using a dual recombinase genetically engineered mouse model of pancreatic cancer, delayed formation of invasive disease, while increasing CD8+ T cell infiltration. Additionally, Arg1 deletion induced compensatory mechanisms, including Arg1 overexpression in epithelial cells, namely Tuft cells, and Arg2 overexpression in a subset of macrophages. To overcome these compensatory mechanisms, we used a pharmacological approach to inhibit arginase. Treatment of established tumors with the arginase inhibitor CB-1158 exhibited further increased CD8+ T cell infiltration, beyond that seen with the macrophage-specific knockout, and sensitized the tumors to anti-PD1 immune checkpoint blockade. Our data demonstrate that Arg1 drives immune suppression in pancreatic cancer by depleting arginine and inhibiting T cell activation.

The GLP-1 receptor agonist exenatide ameliorates neuroinflammation, locomotor activity, and anxiety-like behavior in mice with diet-induced obesity through the modulation of microglial M2 polarization and downregulation of SR-A4.

Obesity is associated with multiple comorbidities, such as metabolic abnormalities and cognitive dysfunction. Moreover, accumulating evidence indicates that neurodegenerative disorders are associated with chronic neuroinflammation. GLP-1 receptor agonists (RAs) have been extensively studied as a treatment for type 2 diabetes. Emerging evidence has demonstrated a protective effect of GLP-1 RAs on neurodegenerative disease, which is independent of its glucose-lowering effects. In this study, we aimed to examine the effects of a long-acting GLP-1 RA, exenatide, on high-fat diet (HFD)-induced neuroinflammation and related brain function impairment. First, mice treated with exenatide exhibited significantly reduced HFD-increased body weight and blood glucose. In an open field test, exenatide treatment ameliorated the reduction in local motor activity and anxiety in HFD-fed mice. Moreover, HFD induced astrogliosis, microgliosis, and upregulation of IL-1β, IL-6 and TNF-α in hippocampus and cortex. Exenatide treatment reduced HFD-induced astrogliosis and IL-1β and TNF-α expressions. Moreover, exenatide increased phosphor-ERK and M2-type microglia marker arginase-1 expression in the hippocampus and cortex. In addition, we found that scavenger receptor-A4 protein expression was induced by HFD and was subsequently inhibited by exenatide. SR-A4 knockout reversed the locomotor activity impairment but not the anxiety behavior caused by HFD consumption. SR-A4 knockout also reduced HFD-induced neuroinflammation, as shown by the reduced expression of GFAP and IBA-1 compared with that in wild-type control mice. These results demonstrate that exenatide decreases HFD-increased neuroinflammation and promotes anti-inflammatory M2 differentiation. The inhibition of SR-A4 by exenatide exerts anti-inflammatory activity.

Effects of interleukin-4-modified gold nanozymes on the full-thickness skin defects in diabetic mice

Effects of interleukin-4-modified gold nanozymes on the full-thickness skin defects in diabetic mice

Licochalcone E, a β-Amyloid Aggregation Inhibitor, Regulates Microglial M1/M2 Polarization via Inhibition of CTL1-Mediated Choline Uptake.

Alzheimer's disease (AD) is thought to be a series of neuroinflammatory diseases caused by abnormal deposits of amyloid-β (Aβ) and tau protein in the brain as part of its etiology. We focused on Aβ aggregation and M1 and M2 microglial polarity in microglia to search for novel therapeutic agents. It has been reported that the inhibition of choline uptake via choline transporter-like protein 1 (CTL1) in microglia preferentially induces M2 microglial polarity. However, the role of the choline transport system on the regulation of microglial M1/M2 polarity in AD is not fully understood. Licochalcones (Licos) A-E, flavonoids extracted from licorice, have been reported to have immunological anti-inflammatory effects, and Lico A inhibits Aβ aggregation. In this study, we compared the efficacy of five Licos, from Lico A to E, at inhibiting Aβ1-42 aggregation. Among the five Licos, Lico E was selected to investigate the relationship between the inhibition of choline uptake and microglial M1/M2 polarization using the immortalized mouse microglial cell line SIM-A9. We newly found that Lico E inhibited choline uptake and Aβ1-42 aggregation in SIM-A9 cells in a concentration-dependent manner, suggesting that the inhibitory effect of Lico E on choline uptake is mediated by CTL1. The mRNA expression of tumor necrosis factor (TNF-α), a marker of M1 microglia, was increased by Aβ1-42, and its effect was inhibited by choline deprivation and Lico E in a concentration-dependent manner. In contrast, the mRNA expression of arginase-1 (Arg-1), a marker of M2 microglia, was increased by IL-4, and its effect was enhanced by choline deprivation and Lico E. We found that Lico E has an inhibitory effect on Aβ aggregation and promotes polarity from M1 to M2 microglia via inhibition of the CTL1 function in microglia. Thus, Lico E may become a leading compound for a novel treatment of AD.

Effect of CDK8/19 inhibition on IL-4-induced arginase-1 expression in macrophages.

Effect of CDK8/19 inhibition on IL-4-induced arginase-1 expression in macrophages.

Amelioration of DSS-induced colitis in mice by TNF-α-stimulated mesenchymal stem cells derived from feline adipose tissue via COX-2/PGE2 activation.

Mesenchymal stem cells (MSCs) have been investigated as therapeutic agents for inflammatory bowel disease (IBD). Stimulation of MSCs with pro-inflammatory cytokines is an approach to enhance their immunomodulatory effects. However, further investigation is required to support their application in immune-mediated disorders and companion animals. This study aimed to assess the therapeutic effect of tumor necrosis factor (TNF)-α-stimulated feline adipose tissue-derived MSCs (fAT-MSCs) in a dextran sulfate sodium (DSS)-induced colitis mouse model. Colitis mice was made by drinking water with 3% DSS and fAT-MSCs were injected intraperitoneally. Colons were collected on day 10. The severity of the disease was evaluated and compared. Raw 264.7 cells were cultured with the conditioned medium to determine the mechanism, using quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. TNF-α-stimulated fAT-MSCs more improved severity of DSS-induced colitis in disease activity, colon length, histologic score, and inflammatory cytokine. In sectionized colon tissues, the group comprising TNF-α-stimulated fAT-MSCs had higher proportion of CD11b+CD206+ macrophages than in the other groups. In vitro, TNF-α-stimulation increased cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) secretion from fAT-MSCs. The conditioned medium from TNF-α-stimulated fAT-MSCs enhanced the expression of interleukin-10 and arginase-1 in LPS-activated Raw 264.7 cells. These results represent that TNF-α-stimulated fat-mscs ameliorate the inflamed colon more effectively. Furthermore, we demonstrated that the effectiveness was interlinked with the COX-2/PGE2 pathway.