1
|
Allen JN, Dey A, Cai J, Zhang J, Tian Y, Kennett M, Ma Y, Liang TJ, Patterson AD, Hankey-Giblin PA. Metabolic Profiling Reveals Aggravated Non-Alcoholic Steatohepatitis in High-Fat High-Cholesterol Diet-Fed Apolipoprotein E-Deficient Mice Lacking Ron Receptor Signaling. Metabolites 2020; 10:metabo10080326. [PMID: 32796650 PMCID: PMC7464030 DOI: 10.3390/metabo10080326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/13/2022] Open
Abstract
Non-alcoholic steatohepatitis (NASH) represents the progressive sub-disease of non-alcoholic fatty liver disease that causes chronic liver injury initiated and sustained by steatosis and necroinflammation. The Ron receptor is a tyrosine kinase of the Met proto-oncogene family that potentially has a beneficial role in adipose and liver-specific inflammatory responses, as well as glucose and lipid metabolism. Since its discovery two decades ago, the Ron receptor has been extensively investigated for its differential roles on inflammation and cancer. Previously, we showed that Ron expression on tissue-resident macrophages limits inflammatory macrophage activation and promotes a repair phenotype, which can retard the progression of NASH in a diet-induced mouse model. However, the metabolic consequences of Ron activation have not previously been investigated. Here, we explored the effects of Ron receptor activation on major metabolic pathways that underlie the development and progression of NASH. Mice lacking apolipoprotein E (ApoE KO) and double knockout (DKO) mice that lack ApoE and Ron were maintained on a high-fat high-cholesterol diet for 18 weeks. We observed that, in DKO mice, the loss of ligand-dependent Ron signaling aggravated key pathological features in steatohepatitis, including steatosis, inflammation, oxidation stress, and hepatocyte damage. Transcriptional programs positively regulating fatty acid (FA) synthesis and uptake were upregulated in the absence of Ron receptor signaling, whereas lipid disposal pathways were downregulated. Consistent with the deregulation of lipid metabolism pathways, the DKO animals exhibited increased accumulation of FAs in the liver and decreased level of bile acids. Altogether, ligand-dependent Ron receptor activation provides protection from the deregulation of major metabolic pathways that initiate and aggravate non-alcoholic steatohepatitis.
Collapse
Affiliation(s)
- Joselyn N. Allen
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
| | - Adwitia Dey
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
| | - Jingwei Cai
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
| | - Jingtao Zhang
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
| | - Yuan Tian
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
| | - Mary Kennett
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
| | - Yanling Ma
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD 20814, USA; (Y.M.); (T.J.L.)
| | - T. Jake Liang
- Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD 20814, USA; (Y.M.); (T.J.L.)
| | - Andrew D. Patterson
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
- Correspondence: (A.D.P.); (P.A.H.-G.); Tel.: +1-814-867-4565; (A.D.P.); +1-814-863-0128 (P.A.H.-G.)
| | - Pamela A. Hankey-Giblin
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA 16802, USA; (J.N.A.); (A.D.); (J.C.); (J.Z.); (Y.T.); (M.K.)
- Correspondence: (A.D.P.); (P.A.H.-G.); Tel.: +1-814-867-4565; (A.D.P.); +1-814-863-0128 (P.A.H.-G.)
| |
Collapse
|
2
|
Wang Z, Vaughan TY, Zhu W, Chen Y, Fu G, Medrzycki M, Nishio H, Bunting ST, Hankey-Giblin PA, Nusrat A, Parkos CA, Wang D, Wen R, Bunting KD. Gab2 and Gab3 Redundantly Suppress Colitis by Modulating Macrophage and CD8 + T-Cell Activation. Front Immunol 2019; 10:486. [PMID: 30936879 PMCID: PMC6431666 DOI: 10.3389/fimmu.2019.00486] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/22/2019] [Indexed: 12/13/2022] Open
Abstract
Inflammatory Bowel Disease (IBD) is a multi-factorial chronic inflammation of the gastrointestinal tract prognostically linked to CD8+ T-cells, but little is known about their mechanism of activation during initiation of colitis. Here, Grb2-associated binding 2/3 adaptor protein double knockout mice (Gab2/3−/−) were generated. Gab2/3−/− mice, but not single knockout mice, developed spontaneous colitis. To analyze the cellular mechanism, reciprocal bone marrow (BM) transplantation demonstrated a Gab2/3−/− hematopoietic disease-initiating process. Adoptive transfer showed individual roles for macrophages and T-cells in promoting colitis development in vivo. In spontaneous disease, intestinal intraepithelial CD8+ but much fewer CD4+, T-cells from Gab2/3−/− mice with rectal prolapse were more proliferative. To analyze the molecular mechanism, reduced PI3-kinase/Akt/mTORC1 was observed in macrophages and T-cells, with interleukin (IL)-2 stimulated T-cells showing increased pSTAT5. These results illustrate the importance of Gab2/3 collectively in signaling responses required to control macrophage and CD8+ T-cell activation and suppress chronic colitis.
Collapse
Affiliation(s)
- Zhengqi Wang
- Division of Hem/Onc/BMT, Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, GA, United States
| | - Tamisha Y Vaughan
- Division of Hem/Onc/BMT, Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, GA, United States
| | - Wandi Zhu
- Division of Hem/Onc/BMT, Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, GA, United States
| | - Yuhong Chen
- BloodCenter of Wisconsin, Milwaukee, WI, United States
| | - Guoping Fu
- BloodCenter of Wisconsin, Milwaukee, WI, United States
| | - Magdalena Medrzycki
- Division of Hem/Onc/BMT, Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, GA, United States
| | - Hikaru Nishio
- Department of Pathology, Emory University, Atlanta, GA, United States
| | - Silvia T Bunting
- Department of Pathology, Children's Healthcare of Atlanta, Atlanta, GA, United States
| | - Pamela A Hankey-Giblin
- Department of Veterinary Science, Pennsylvania State University, University Park, PA, United States
| | - Asma Nusrat
- Department of Pathology, Emory University, Atlanta, GA, United States.,Department of Pathology, University of Michigan, Ann Arbor, MI, United States
| | - Charles A Parkos
- Department of Pathology, Emory University, Atlanta, GA, United States.,Department of Pathology, University of Michigan, Ann Arbor, MI, United States
| | - Demin Wang
- BloodCenter of Wisconsin, Milwaukee, WI, United States
| | - Renren Wen
- BloodCenter of Wisconsin, Milwaukee, WI, United States
| | - Kevin D Bunting
- Division of Hem/Onc/BMT, Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University, Atlanta, GA, United States
| |
Collapse
|
3
|
Allen J, Zhang J, Quickel MD, Kennett M, Patterson AD, Hankey-Giblin PA. Ron Receptor Signaling Ameliorates Hepatic Fibrosis in a Diet-Induced Nonalcoholic Steatohepatitis Mouse Model. J Proteome Res 2018; 17:3268-3280. [PMID: 30091925 DOI: 10.1021/acs.jproteome.8b00379] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Liver fibrosis is commonly observed in the terminal stages of nonalcoholic steatohepatitis (NASH) and with no specific and effective antifibrotic therapies available, this disease is a major global health burden. The MSP/Ron receptor axis has been shown to have anti-inflammatory properties in a number of mouse models, due at least in part, to its ability to limit pro-inflammatory responses in tissue-resident macrophages and hepatocytes. In this study, we established the role of the Ron receptor in steatohepatitis-induced hepatic fibrosis using Ron ligand domain knockout mice on an apolipoprotein E knockout background (DKO). After 18 weeks of high-fat high-cholesterol feeding, loss of Ron activation resulted in exacerbated NASH-associated steatosis which is precedent to hepatocellular injury, inflammation and fibrosis. 1H nuclear magnetic resonance (NMR)-based metabolomics identified significant changes in serum metabolites that can modulate the intrahepatic lipid pool in hepatic steatosis. Serum from DKO mice had higher concentrations of lipids, VLDL/LDL and pyruvate, whereas glycine levels were reduced. Parallel to the aggravated steatohepatitis, increased accumulation of collagen, inflammatory immune cells and collagen producing-myofibroblasts were seen in the livers of DKO mice. Gene expression profiling revealed that DKO mice exhibited elevated expression of genes encoding Ron receptor ligand MSP, collagens, ECM remodeling proteins and pro-fibrogenic cytokines in the liver. Our results demonstrate the protective effects of Ron receptor activation on NASH-induced hepatic fibrosis.
Collapse
Affiliation(s)
- Joselyn Allen
- Department of Veterinary and Biomedical Sciences , The Pennsylvania State University , University Park , Pennsylvania United States
| | - Jingtao Zhang
- Department of Veterinary and Biomedical Sciences , The Pennsylvania State University , University Park , Pennsylvania United States
| | - Michael D Quickel
- Department of Veterinary and Biomedical Sciences , The Pennsylvania State University , University Park , Pennsylvania United States
| | - Mary Kennett
- Department of Veterinary and Biomedical Sciences , The Pennsylvania State University , University Park , Pennsylvania United States
| | - Andrew D Patterson
- Department of Veterinary and Biomedical Sciences , The Pennsylvania State University , University Park , Pennsylvania United States
| | - Pamela A Hankey-Giblin
- Department of Veterinary and Biomedical Sciences , The Pennsylvania State University , University Park , Pennsylvania United States
| |
Collapse
|
4
|
Fraser JW, Dey A, Nettleford SK, Zhao L, Hankey-Giblin PA, Prabhu KS, Xiong N, Paulson RF. GDF15 and BMP4 co-regulate stress erythropoiesis cmaintain erythroid homeostasis and resolve inflammation during infection. The Journal of Immunology 2018. [DOI: 10.4049/jimmunol.200.supp.47.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Bone marrow steady state erythropoiesis maintains erythrocyte homeostasis. However, during inflammation it is unable to generate sufficient erythrocytes as pro-inflammatory cytokines inhibit medullary output. At these times extra-medullary stress erythropoiesis (SE) predominates. SE utilizes progenitors and signals that are distinct from the steady state. Using a model of sterile inflammation, we have recently shown that the inflammatory signals that suppress steady state erythropoiesis activate SE. While we have demonstrated an important role for SE in maintaining erythroid homeostasis during inflammation, the potential for SE to directly influence inflammation remains largely unexplored. We report the first study to demonstrate the importance of SE in the context of a bona fide infection using the model pathogen Citrobacter rodentium. We observed that infection rapidly induces SE in the spleen, however mice mutant for either of the two key signals (BMP4 and GDF15) that regulate SE exhibited compromised recovery following infection. Inflammation was significantly increased while FoxP3+ regulatory T-cells (Tregs) were decreased in these mice. In vitro, induction of Tregs was defective when naïve CD4+ T cells from mutant mice were used. The addition of BMP4 or GDF15 into these cultures rescued Treg induction. These data suggest a new model that includes a more extensive interplay between erythroid homeostasis and the immune response. In this model Treg induction, like the activation of SE, depends on the action of both BMP4 and GDF15. Thus, BMP4 and GDF15 may function together during the critical period immediately following inflammation to synchronously maintain both erythroid homeostasis and regulate inflammation in vivo.
Collapse
|
5
|
Allen JN, Kennett M, Patterson A, Hankey-Giblin PA. Loss of MSP-dependent Ron receptor signaling exacerbates liver fibrosis in a high fat high cholesterol diet-induced ApoE KO mouse model. The Journal of Immunology 2018. [DOI: 10.4049/jimmunol.200.supp.42.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
Liver fibrosis marks the turning point of non-alcoholic steatohepatitis and with no specific and effective anti-fibrotic therapies available, this disease is a major global health burden. Here, we established the novel role of the Ron receptor in mitigating liver fibrosis. For 18 weeks, apolipoprotein E (ApoE KO) and ApoE x Ron double knockout (DKO) mice were fed a fat and cholesterol-rich diet. Livers from DKO animals exhibited increased accumulation of sirius red-stained collagen. Immunohistochemistry of αSMA revealed that DKO livers had increased activation of collagen-producing hepatic stellate cells. In agreement with this, DKO livers exhibited higher expression of pro-fibrogenic molecules, PDGF, CTGF, and TGFβ. Additionally, DKO mice exhibited increased hepatic expression of collagens (Types 1, 3, and 4) and ECM remodeling proteins (MMP-2 and TIMP-1). The expression of pro-fibrogenic inflammatory cytokines (TNFα and IL-12b), receptors (TLR-4), and chemokines (MIP-2, CCL2, and CCL5) were significantly higher in DKO livers. DKO livers also exhibited increased infiltration of F4/80+ Kupffer cells, which are well-known to mediate the majority of cytokine and chemokine expression in fibrotic livers. Ron also attenuated several risk factors of liver fibrosis including insulin resistance, steatosis, hepatocellular damage, and inflammation. Despite lifestyle changes and pharmacotherapies for treating etiologies of liver fibrosis, the disrupted liver homeostasis often remains and requires effective treatments. Investigating the protective functions of Ron offers a pharmacological target for resolving the steatohepatitis spectrum.
Collapse
|
6
|
Dey A, Allen JN, Fraser JW, Snyder LM, Tian Y, Zhang L, Paulson RF, Patterson A, Cantorna MT, Hankey-Giblin PA. Neuroprotective Role of the Ron Receptor Tyrosine Kinase Underlying Central Nervous System Inflammation in Health and Disease. Front Immunol 2018; 9:513. [PMID: 29616029 PMCID: PMC5868034 DOI: 10.3389/fimmu.2018.00513] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/27/2018] [Indexed: 12/19/2022] Open
Abstract
Neurodegeneration is a critical problem in aging populations and is characterized by severe central nervous system (CNS) inflammation. Macrophages closely regulate inflammation in the CNS and periphery by taking on different activation states. The source of inflammation in many neurodegenerative diseases has been preliminarily linked to a decrease in the CNS M2 macrophage population and a subsequent increase in M1-mediated neuroinflammation. The Recepteur D'Origine Nantais (Ron) is a receptor tyrosine kinase expressed on tissue-resident macrophages including microglia. Activation of Ron by its ligand, macrophage-stimulating protein, attenuates obesity-mediated inflammation in the periphery. An in vivo deletion of the ligand binding domain of Ron (Ron-/-) promotes inflammatory (M1) and limits a reparative (M2) macrophage activation. However, whether or not this response influences CNS inflammation has not been determined. In this study, we demonstrate that in homeostasis Ron-/- mice developed an inflammatory CNS niche with increased tissue expression of M1-associated markers when compared to age-matched wild-type (WT) mice. Baseline metabolic analysis of CNS tissue indicates exacerbated levels of metabolic stress in Ron-/- CNS. In a disease model of multiple sclerosis, experimental autoimmune encephalomyelitis, Ron-/- mice exhibit higher disease severity when compared to WT mice associated with increased CNS tissue inflammation. In a model of diet-induced obesity (DIO), Ron-/- mice exhibit exacerbated CNS inflammation with decreased expression of the M2 marker Arginase-1 (Arg-1) and a robust increase in M1 markers compared to WT mice following 27 weeks of DIO. Collectively, these results illustrate that activation of Ron in the CNS could be a potential therapeutic approach to treating various grades of CNS inflammation underlying neurodegeneration.
Collapse
Affiliation(s)
- Adwitia Dey
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Joselyn N Allen
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - James W Fraser
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Lindsay M Snyder
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Yuan Tian
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States.,CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, University of Chinese Academy of Sciences, Wuhan, China
| | - Limin Zhang
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Robert F Paulson
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Andrew Patterson
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Margherita T Cantorna
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Pamela A Hankey-Giblin
- Center for Molecular Immunology and Infectious Diseases, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, United States
| |
Collapse
|
7
|
Allen JN, Dey A, Nissly R, Fraser J, Yu S, Balandaram G, Peters JM, Hankey-Giblin PA. Isolation, Characterization, and Purification of Macrophages from Tissues Affected by Obesity-related Inflammation. J Vis Exp 2017. [PMID: 28447981 DOI: 10.3791/55445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Obesity promotes a chronic inflammatory state that is largely mediated by tissue-resident macrophages as well as monocyte-derived macrophages. Diet-induced obesity (DIO) is a valuable model in studying the role of macrophage heterogeneity; however, adequate macrophage isolations are difficult to acquire from inflamed tissues. In this protocol, we outline the isolation steps and necessary troubleshooting guidelines derived from our studies for obtaining a suitable population of tissue-resident macrophages from mice following 18 weeks of high-fat (HFD) or high-fat/high-cholesterol (HFHCD) diet intervention. This protocol focuses on three hallmark tissues studied in obesity and atherosclerosis including the liver, white adipose tissues (WAT), and the aorta. We highlight how dualistic usage of flow cytometry can achieve a new dimension of isolation and characterization of tissue-resident macrophages. A fundamental section of this protocol addresses the intricacies underlying tissue-specific enzymatic digestions and macrophage isolation, and subsequent cell-surface antibody staining for flow cytometric analysis. This protocol addresses existing complexities underlying fluorescent-activated cell sorting (FACS) and presents clarifications to these complexities so as to obtain broad range characterization from adequately sorted cell populations. Alternate enrichment methods are included for sorting cells, such as the dense liver, allowing for flexibility and time management when working with FACS. In brief, this protocol aids the researcher to evaluate macrophage heterogeneity from a multitude of inflamed tissues in a given study and provides insightful troubleshooting tips that have been successful for favorable cellular isolation and characterization of immune cells in DIO-mediated inflammation.
Collapse
Affiliation(s)
- Joselyn N Allen
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University;
| | - Adwitia Dey
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University
| | - Ruth Nissly
- Microscopy and Cytometry Facility, The Huck Institutes of Life Sciences, Pennsylvania State University
| | - James Fraser
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University
| | - Shan Yu
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University
| | - Gayathri Balandaram
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University
| | - Jeffrey M Peters
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University
| | | |
Collapse
|
8
|
Yu S, Allen JN, Dey A, Zhang L, Balandaram G, Kennett MJ, Xia M, Xiong N, Peters JM, Patterson A, Hankey-Giblin PA. The Ron Receptor Tyrosine Kinase Regulates Macrophage Heterogeneity and Plays a Protective Role in Diet-Induced Obesity, Atherosclerosis, and Hepatosteatosis. J I 2016; 197:256-65. [DOI: 10.4049/jimmunol.1600450] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022]
|
9
|
Dey A, Snyder L, Weaver V, Cantorna MT, Hankey-Giblin PA. The Ron receptor tyrosine kinase regulates inflammatory response in an experimental model of multiple sclerosis. The Journal of Immunology 2016. [DOI: 10.4049/jimmunol.196.supp.188.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Abstract
In the experimental autoimmune encephalitis (EAE) murine model of multiple sclerosis (MS), both central nervous system (CNS)-resident macrophages (microglia) and infiltrating monocyte-derived macrophages contribute to disease progression. The Ron receptor tyrosine kinase is expressed on tissue resident macrophages including microglia and is involved in regulating inflammatory responses. An in vivo deletion of Ron (Ron KO) promotes inflammatory macrophage activation (M1) and limits a reparative macrophage phenotype (M2). Herein we investigated whether Ron expression plays a critical role in regulating disease progression in EAE. Ron KO mice exhibit delayed onset of EAE (day 14) compared to Wild-Type (WT) (day 10), however Ron KO mice exhibit greater peak severity at onset. Ron KO mice display T-cell mediated peripheral inflammation, as demonstrated by the significant increase in the secretion of interferon gamma (IFNγ) but not IL-17 and IL-10. At day 14, cultured lymph node cells from Ron KO mice exhibit increased expression of M1-macrophage mediated biomarkers iNOS, COX-2, IL-6, IL12B, IL1β and TNF-α. A likely cause of this increased inflammatory response can in part be attributed to a T-cell mediated increase in IFNγ. Furthermore, CNS tissues from Ron KO mice at day 14 have increased gene expression of hallmark inflammatory biomarkers iNOS, IL12B and COX-2. The results indicate an interplay between the innate and adaptive immune system in fostering an M1-macrophage mediated inflammatory state, as the underlying factor for the observed increase in disease severity in Ron KO mice. Maintenance of Ron expressing macrophages could then be a potential therapeutic approach to treating MS symptoms.
Collapse
|
10
|
Feaga HA, Quickel MD, Hankey-Giblin PA, Keiler KC. Human Cells Require Non-stop Ribosome Rescue Activity in Mitochondria. PLoS Genet 2016; 12:e1005964. [PMID: 27029019 PMCID: PMC4814080 DOI: 10.1371/journal.pgen.1005964] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/07/2016] [Indexed: 12/04/2022] Open
Abstract
Bacteria use trans-translation and the alternative rescue factors ArfA (P36675) and ArfB (Q9A8Y3) to hydrolyze peptidyl-tRNA on ribosomes that stall near the 3' end of an mRNA during protein synthesis. The eukaryotic protein ICT1 (Q14197) is homologous to ArfB. In vitro ribosome rescue assays of human ICT1 and Caulobacter crescentus ArfB showed that these proteins have the same activity and substrate specificity. Both ArfB and ICT1 hydrolyze peptidyl-tRNA on nonstop ribosomes or ribosomes stalled with ≤6 nucleotides extending past the A site, but are unable to hydrolyze peptidyl-tRNA when the mRNA extends ≥14 nucleotides past the A site. ICT1 provided sufficient ribosome rescue activity to support viability in C. crescentus cells that lacked both trans-translation and ArfB. Likewise, expression of ArfB protected human cells from death when ICT1 was silenced with siRNA. These data indicate that ArfB and ICT1 are functionally interchangeable, and demonstrate that ICT1 is a ribosome rescue factor. Because ICT1 is essential in human cells, these results suggest that ribosome rescue activity in mitochondria is required in humans. Ribosomes can stall during protein synthesis on truncated or damaged mRNAs that lack a stop codon. In bacteria, these “non-stop” ribosomes are rescued by trans-translation or by an alternative rescue factor, ArfA or ArfB. Most eukaryotes do not have trans-translation, but mammals have a homolog of ArfB named ICT1. ICT1 is targeted to mitochondria, and is essential in human cells. Here, we show that human ICT1 and ArfB from the bacterium Caulobacter crescentus have the same biochemical activity and specificity. We also demonstrate that ICT1 and ArfB are functionally interchangeable in both bacteria and human cells. Collectively, this work demonstrates a new essential function in human cells—rescue of mitochondrial non-stop translation complexes.
Collapse
Affiliation(s)
- Heather A. Feaga
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Michael D. Quickel
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Pamela A. Hankey-Giblin
- Department of Veterinary and Biomedical Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kenneth C. Keiler
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
11
|
Dey A, Allen J, Hankey-Giblin PA. Ontogeny and polarization of macrophages in inflammation: blood monocytes versus tissue macrophages. Front Immunol 2015; 5:683. [PMID: 25657646 PMCID: PMC4303141 DOI: 10.3389/fimmu.2014.00683] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/17/2014] [Indexed: 12/23/2022] Open
Abstract
The explosion of new information in recent years on the origin of macrophages in the steady-state and in the context of inflammation has opened up numerous new avenues of investigation and possibilities for therapeutic intervention. In contrast to the classical model of macrophage development, it is clear that tissue-resident macrophages can develop from yolk sac-derived erythro-myeloid progenitors, fetal liver progenitors, and bone marrow-derived monocytes. Under both homeostatic conditions and in response to pathophysiological insult, the contribution of these distinct sources of macrophages varies significantly between tissues. Furthermore, while all of these populations of macrophages appear to be capable of adopting the polarized M1/M2 phenotypes, their respective contribution to inflammation, resolution of inflammation, and tissue repair remains poorly understood and is likely to be tissue- and disease-dependent. A better understanding of the ontology and polarization capacity of macrophages in homeostasis and disease will be essential for the development of novel therapies that target the inherent plasticity of macrophages in the treatment of acute and chronic inflammatory disease.
Collapse
Affiliation(s)
- Adwitia Dey
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University , University Park, PA , USA ; Graduate Program in Physiology, The Pennsylvania State University , University Park, PA , USA
| | - Joselyn Allen
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University , University Park, PA , USA ; Graduate Program in Immunology and Infectious Disease, The Pennsylvania State University , University Park, PA , USA
| | - Pamela A Hankey-Giblin
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University , University Park, PA , USA ; Graduate Program in Physiology, The Pennsylvania State University , University Park, PA , USA ; Graduate Program in Immunology and Infectious Disease, The Pennsylvania State University , University Park, PA , USA
| |
Collapse
|