Browsing by Subject "Macrophages"
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Item 12-Lipoxygenase governs the innate immune pathogenesis of islet inflammation and autoimmune diabetes(The American Society for Clinical Investigation, 2021-07-22) Kulkarni, Abhishek; Pineros, Annie R.; Walsh, Melissa A.; Casimiro, Isabel; Ibrahim, Sara; Hernandez-Perez, Marimar; Orr, Kara S.; Glenn, Lindsey; Nadler, Jerry L.; Morris, Margaret A.; Tersey, Sarah A.; Mirmira, Raghavendra G.; Anderson, Ryan M.; Pediatrics, School of MedicineMacrophages and related myeloid cells are innate immune cells that participate in the early islet inflammation of type 1 diabetes (T1D). The enzyme 12-lipoxygenase (12-LOX) catalyzes the formation of proinflammatory eicosanoids, but its role and mechanisms in myeloid cells in the pathogenesis of islet inflammation have not been elucidated. Leveraging a model of islet inflammation in zebrafish, we show here that macrophages contribute significantly to the loss of β cells and the subsequent development of hyperglycemia. The depletion or inhibition of 12-LOX in this model resulted in reduced macrophage infiltration into islets and the preservation of β cell mass. In NOD mice, the deletion of the gene encoding 12-LOX in the myeloid lineage resulted in reduced insulitis with reductions in proinflammatory macrophages, a suppressed T cell response, preserved β cell mass, and almost complete protection from the development of T1D. 12-LOX depletion caused a defect in myeloid cell migration, a function required for immune surveillance and tissue injury responses. This effect on migration resulted from the loss of the chemokine receptor CXCR3. Transgenic expression of the gene encoding CXCR3 rescued the migratory defect in zebrafish 12-LOX morphants. Taken together, our results reveal a formative role for innate immune cells in the early pathogenesis of T1D and identify 12-LOX as an enzyme required to promote their prodiabetogenic phenotype in the context of autoimmunity.Item Abnormalities in Osteoclastogenesis and Decreased Tumorigenesis in Mice Deficient for Ovarian Cancer G Protein-Coupled Receptor 1(PLOS, 2009-05-29) Li, Hui; Wang, Dongmei; Singh, Lisam Shanjukumar; Berk, Michael; Tan, Haiyan; Zhao, Zhenwen; Steinmetz, Rosemary; Kirmani, Kashif; Wei, Gang; Xu, Yan; Obstetrics and Gynecology, School of MedicineOvarian cancer G protein-coupled receptor 1 (OGR1) has been shown to be a proton sensing receptor in vitro. We have shown that OGR1 functions as a tumor metastasis suppressor gene when it is over-expressed in human prostate cancer cells in vivo. To examine the physiological functions of OGR1, we generated conditional OGR1 deficient mice by homologous recombination. OGR1 deficient mice were viable and upon gross-inspection appeared normal. Consistent with in vitro studies showing that OGR1 is involved in osteoclastogenesis, reduced osteoclasts were detected in OGR1 deficient mice. A pH-dependent osteoclasts survival effect was also observed. However, overall abnormality in the bones of these animals was not observed. In addition, melanoma cell tumorigenesis was significantly inhibited in OGR1 deficient mice. OGR1 deficient mice in the mixed background produced significantly less peritoneal macrophages when stimulated with thioglycolate. These macrophages also showed altered extracellular signal-regulated kinases (ERK) activation and nitric oxide (NO) production in response to lipopolysaccharide. OGR1-dependent pH responses assessed by cAMP production and cell survival in macrophages or brown fat cells were not observed, presumably due to the presence of other proton sensing receptors in these cells. Our results indicate that OGR1's role in osteoclastogenesis is not strong enough to affect overall bone development and its role in tumorigenesis warrants further investigation. The mice generated can be potentially used for several disease models, including cancers or osteoclast-related diseases.Item Activin B Promotes Hepatic Fibrogenesis(2019-08) Wang, Yan; Dai, Guoli; Berbari, Nicolas; Yaden, Benjamin; Liangpunsakul, Suthat; Skalnik, David G.Liver fibrosis is a common consequence of various chronic liver diseases. Although transforming growth factor β 1 (TGFβ1) expression is known to be associated with liver fibrosis, the reduced clinical efficacy of TGFβ1 inhibition or the inefficiency to completely prevent liver fibrosis in mice with liver-specific knockout of TGF receptor II suggests that other factors can mediate liver fibrogenesis. As a TGFβ superfamily ligand, activin A signaling modulates liver injury by prohibiting hepatocyte proliferation, mediating hepatocyte apoptosis, promoting Kupffer cell activation, and inducing hepatic stellate cell (HSC) activation in vitro. However, the mechanism of action and in vivo functional significance of activin A in liver fibrosis models remain uncertain. Moreover, whether activin B, another ligand structurally related to activin A, is involved in liver fibrogenesis is not yet known. This study aimed to investigate the role of activin A and B in liver fibrosis initiation and progression. The levels of hepatic and circulating activin B and A were analyzed in patients with various chronic liver diseases, including end-stage liver diseases (ESLD), non-alcoholic steatohepatitis (NASH), and alcoholic liver disease (ALD). In addition, their levels were measured in mouse carbon tetrachloride (CCl4), bile duct ligation (BDL), and ALD liver injury models. Mouse primary hepatocytes, RAW264.7 cells, and LX-2 cells were used as in vitro models of hepatocytes, macrophages, and HSCs, respectively. The specificity and potency of anti-activin B monoclonal antibody (mAb) and anti-activin A mAb were evaluated using Smad2/3 luciferase assay. Activin A, activin B, or their combination were immunologically inactivated by the neutralizing mAbs in mice with progressive or established liver fibrosis induced by CCl4 or with developing cholestatic liver fibrosis induced by BDL surgery. In patients with ESLD, NASH, and ALD, increases in hepatic and circulating activin B, but not activin A, were associated with liver fibrosis, irrespective of etiology. In mice with CCl4-, BDL-, or alcohol-induced liver injury, activin B was persistently elevated in the liver and circulation, whereas activin A showed only transient increases. Activin B was expressed and secreted mainly by the hepatocytes and other cells, including cholangiocytes, activated HSCs, and immune cells. Exogenous administration of activin B promoted hepatocyte injury, activated macrophages to release cytokines, and induced a pro-fibrotic expression profile and septa formation in HSCs. Co-treatment of activin A and B interdependently activated the chemokine (C-X-C motif) ligand 1 (CXCL1)/inducible nitric oxide synthase (iNOS) pathway in macrophages and additively upregulated connective tissue growth factor expression in HSCs. Activin B and A had redundant, unique, and interactive effects on the transcripts related to HSC activation. The neutralization of activin B attenuated the development of liver fibrosis and improved liver function in mice with CCl4- or BDL-induced liver fibrosis and largely reversed the already established liver fibrosis in the CCl4 mouse model. These effects were improved by the administration of additional anti-activin A antibody. Combination of both antibodies also inhibited hepatic and circulating inflammatory cytokine production in the BDL mouse model. In conclusion, activin B is a potential circulating biomarker and potent promotor of liver fibrosis. Its levels in the liver and circulation increase significantly in both acute and chronic states of liver injury. Activin B might additively or interdependently cooperate with activin A, which directly acts on multiple liver cell populations during liver injury and fibrosis, as the combination of both proteins increases pro-inflammatory and pro-fibrotic responses in vitro. In addition, the neutralization of both activin A and activin B in vivo enhances the preventive and reversible effects of liver injury and fibrosis compared to that when activin B alone is neutralized. Our data reveal a novel target of liver fibrosis and the mechanism of activin B-mediated initiation of this process by damaging hepatocytes and activating macrophages and HSCs. Our findings show that activin B promotes hepatic fibrogenesis, and that targeting of activin B has anti-inflammatory and anti-fibrotic effects, which ameliorate liver injury by preventing or regressing liver fibrosis. Antagonizing either activin B alone or in combination with activin A prevents and regresses liver fibrosis in multiple animal studies, paving way for future clinical studies.Item Altered Macrophage Function Associated with Crystalline Lung Inflammation in Acid Sphingomyelinase Deficiency(American Thoracic Society, 2021) Poczobutt, Joanna M.; Mikosz, Andrew M.; Poirier, Christophe; Beatman, Erica L.; Serban, Karina A.; Gally, Fabienne; Cao, Danting; McCubbrey, Alexandra L.; Cornell, Christina F.; Schweitzer, Kelly S.; Berdyshev, Evgeny V.; Bronova, Irina A.; Paris, François; Petrache, Irina; Medicine, School of MedicineDeficiency of ASM (acid sphingomyelinase) causes the lysosomal storage Niemann-Pick disease (NPD). Patients with NPD type B may develop progressive interstitial lung disease with frequent respiratory infections. Although several investigations using the ASM-deficient (ASMKO) mouse NPD model revealed inflammation and foamy macrophages, there is little insight into the pathogenesis of NPD-associated lung disease. Using ASMKO mice, we report that ASM deficiency is associated with a complex inflammatory phenotype characterized by marked accumulation of monocyte-derived CD11b+ macrophages and expansion of airspace/alveolar CD11c+ CD11b− macrophages, both with increased size, granularity, and foaminess. Both the alternative and classical pathways were activated, with decreased in situ phagocytosis of opsonized (Fc-coated) targets, preserved clearance of apoptotic cells (efferocytosis), secretion of Th2 cytokines, increased CD11c+/CD11b+ cells, and more than a twofold increase in lung and plasma proinflammatory cytokines. Macrophages, neutrophils, eosinophils, and noninflammatory lung cells of ASMKO lungs also exhibited marked accumulation of chitinase-like protein Ym1/2, which formed large eosinophilic polygonal Charcot-Leyden–like crystals. In addition to providing insight into novel features of lung inflammation that may be associated with NPD, our report provides a novel connection between ASM and the development of crystal-associated lung inflammation with alterations in macrophage biology.Item Animal Models of Alcoholic Liver Disease: Pathogenesis and Clinical Relevance(Ingenta, 2017-07-07) Gao, Bin; Xu, Ming-Jiang; Bertola, Adeline; Wang, Hua; Zhou, Zhou; Liangpunsakul, Suthat; Medicine, School of MedicineAlcoholic liver disease (ALD), a leading cause of chronic liver injury worldwide, comprises a range of disorders including simple steatosis, steatohepatitis, cirrhosis, and hepatocellular carcinoma. Over the last five decades, many animal models for the study of ALD pathogenesis have been developed. Recently, a chronic-plus-binge ethanol feeding model was reported. This model induces significant steatosis, hepatic neutrophil infiltration, and liver injury. A clinically relevant model of high-fat diet feeding plus binge ethanol was also developed, which highlights the risk of excessive binge drinking in obese/overweight individuals. All of these models recapitulate some features of the different stages of ALD and have been widely used by many investigators to study the pathogenesis of ALD and to test for therapeutic drugs/components. However, these models are somewhat variable, depending on mouse genetic background, ethanol dose, and animal facility environment. This review focuses on these models and discusses these variations and some methods to improve the feeding protocol. The pathogenesis, clinical relevance, and translational studies of these models are also discussed.Item Assessment of folate receptor-β expression in human neoplastic tissues(Impact Journals, LLC, 2015-06-10) Shen, Jiayin; Putt, Karson S.; Visscher, Daniel W.; Murphy, Linda; Cohen, Cynthia; Singhal, Sunil; Sandusky, George; Feng, Yang; Dimitrov, Dimiter S.; Low, Philip S.; Department of Pathology & Laboratory Medicine, IU School of MedicineOver-expression of folate receptor alpha on cancer cells has been frequently exploited for delivery of folate-targeted imaging and therapeutic agents to tumors. Because limited information exists on expression of the beta isoform of the folate receptor in human cancers (FR-β), we have evaluated the immunohistochemical staining pattern of FR-β in 992 tumor sections from 20 different human cancer types using a new anti-human FR-β monoclonal antibody. FR-β expression was shown to be more pronounced in cells within the stroma, primarily macrophages and macrophage-like cells than cancer cells in every cancer type studied. Moreover, FR-β expression in both cancer and stromal cells was found to be statistically more prominent in females than males. A significant positive correlation was also observed between FR-β expression on stromal cells and both the stage of the cancer and the presence of lymph node metastases. Based on these data we conclude FR-β may constitute a good target for specific delivery of therapeutic agents to activated macrophages and that accumulation of FR-β positive macrophages in the stroma could serve as a useful indicator of a tumor's metastatic potential.Item Blocking porcine sialoadhesin improves extracorporeal porcine liver xenoperfusion with human blood(Wiley, 2013-07) Waldman, Joshua P.; Vogel, Thomas; Burlak, Christopher; Coussios, Constantin; Dominguez, Javier; Friend, Peter; Rees, Michael A.; Surgery, School of MedicineBACKGROUND: Patients in fulminant hepatic failure currently do not have a temporary means of support while awaiting liver transplantation. A potential therapeutic approach for such patients is the use of extracorporeal perfusion with porcine livers as a form of "liver dialysis". During a 72-h extracorporeal perfusion of porcine livers with human blood, porcine Kupffer cells bind to and phagocytose human red blood cells (hRBC) causing the hematocrit to decrease to 2.5% of the original value. Our laboratory has identified porcine sialoadhesin expressed on Kupffer cells as the lectin responsible for binding N-acetylneuraminic acid on the surface of the hRBC. We evaluated whether blocking porcine sialoadhesin prevents the recognition and subsequent destruction of hRBCs seen during extracorporeal porcine liver xenoperfusion. METHODS: Ex vivo studies were performed using wild type pig livers perfused with isolated hRBCs for 72-h in the presence of an anti-porcine sialoadhesin antibody or isotype control. RESULTS: The addition of an anti-porcine sialoadhesin antibody to an extracorporeal porcine liver xenoperfusion model reduces the loss of hRBC over a 72-h period. Sustained liver function was demonstrated throughout the perfusion. CONCLUSIONS: This study illustrates the role of sialoadhesin in mediating the destruction of hRBCs in an extracorporeal porcine liver xenoperfusion model.Item CD45 Phosphatase Inhibits STAT3 Transcription Factor Activity in Myeloid Cells and Promotes Tumor-Associated Macrophage Differentiation(Elsevier, 2016-02-16) Kumar, Vinit; Cheng, Pingyan; Condamine, Thomas; Mony, Sridevi; Languino, Lucia R.; McCaffrey, Judith C.; Hockstein, Neil; Guarino, Michael; Masters, Gregory; Penman, Emily; Denstman, Fred; Xu, Xiaowei; Altieri, Dario C.; Du, Hong; Yan, Cong; Gabrilovich, Dmitry I.; Department of Pathology and Laboratory Medicine, IU School of MedicineRecruitment of monocytic myeloid-derived suppressor cells (MDSCs) and differentiation of tumor-associated macrophages (TAMs) are the major factors contributing to tumor progression and metastasis. We demonstrated that differentiation of TAMs in tumor site from monocytic precursors was controlled by downregulation of the activity of the transcription factor STAT3. Decreased STAT3 activity was caused by hypoxia and affected all myeloid cells but was not observed in tumor cells. Upregulation of CD45 tyrosine phosphatase activity in MDSCs exposed to hypoxia in tumor site was responsible for downregulation of STAT3. This effect was mediated by the disruption of CD45 protein dimerization regulated by sialic acid. Thus, STAT3 has a unique function in the tumor environment in controlling the differentiation of MDSC into TAM, and its regulatory pathway could be a potential target for therapy.Item Cell-intrinsic lysosomal lipolysis is essential for macrophage alternative activation(Nature Publishing Group, 2014-09) Huang, Stanley Ching-Cheng; Everts, Bart; Ivanova, Yulia; O'Sullivan, David; Nascimento, Marcia; Smith, Amber M.; Beatty, Wandy; Love-Gregory, Latisha; Lam, Wing Y.; O'Neill, Christina M.; Yan, Cong; Du, Hong; Abumrad, Nada A.; Urban, Joseph F.; Artyomov, Maxim N.; Pearce, Erika L.; Pearce, Edward J.; Department of Pathology & Laboratory Medicine, IU School of MedicineAlternative (M2) macrophage activation driven through interleukin 4 receptor α (IL-4Rα) is important for immunity to parasites, wound healing, the prevention of atherosclerosis and metabolic homeostasis. M2 polarization is dependent on fatty acid oxidation (FAO), but the source of fatty acids to support this metabolic program has not been clear. We show that the uptake of triacylglycerol substrates via CD36 and their subsequent lipolysis by lysosomal acid lipase (LAL) was important for the engagement of elevated oxidative phosphorylation (OXPHOS), enhanced spare respiratory capacity (SRC), prolonged survival and expression of genes that together define M2 activation. Inhibition of lipolysis suppressed M2 activation during infection with a parasitic helminth, and blocked protective responses against this pathogen. Our findings delineate a critical role for cell-intrinsic lysosomal lipolysis in M2 activation.Item Chlamydia muridarum infection of macrophages elicits bactericidal nitric oxide production via reactive oxygen species and cathepsin B(IAI, 2015-08) Rajaram, Krithika; Nelson, David E.; Department of Microbiology and Immunology, IU School of MedicineThe ability of certain species of Chlamydia to inhibit the biogenesis of phagolysosomes permits their survival and replication within macrophages. The survival of macrophage-adapted chlamydiae correlates with the multiplicity of infection (MOI), and optimal chlamydial growth occurs in macrophages infected at an MOI of ≤1. In this study, we examined the replicative capacity of Chlamydia muridarum in the RAW 264.7 murine macrophage cell line at different MOIs. C. muridarum productively infected these macrophages at low MOIs but yielded few viable elementary bodies (EBs) when macrophages were infected at a moderate (10) or high (100) MOI. While high MOIs caused cytotoxicity and irreversible host cell death, macrophages infected at a moderate MOI did not show signs of cytotoxicity until late in the infectious cycle. Inhibition of host protein synthesis rescued C. muridarum in macrophages infected at a moderate MOI, implying that chlamydial growth was blocked by activated defense mechanisms. Conditioned medium from these macrophages was antichlamydial and contained elevated levels of interleukin 1β (IL-1β), IL-6, IL-10, and beta interferon (IFN-β). Macrophage activation depended on Toll-like receptor 2 (TLR2) signaling, and cytokine production required live, transcriptionally active chlamydiae. A hydroxyl radical scavenger and inhibitors of inducible nitric oxide synthase (iNOS) and cathepsin B also reversed chlamydial killing. High levels of reactive oxygen species (ROS) led to an increase in cathepsin B activity, and pharmacological inhibition of ROS and cathepsin B reduced iNOS expression. Our data demonstrate that MOI-dependent TLR2 activation of macrophages results in iNOS induction via a novel ROS- and cathepsin-dependent mechanism to facilitate C. muridarum clearance.