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Qin D, Zhang Y, Liu F, Xu X, Jiang H, Su Z, Xia L. Spatiotemporal development and the regulatory mechanisms of cardiac resident macrophages: Contribution in cardiac development and steady state. Acta Physiol (Oxf) 2024; 240:e14088. [PMID: 38230805 DOI: 10.1111/apha.14088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/13/2023] [Accepted: 01/01/2024] [Indexed: 01/18/2024]
Abstract
Cardiac resident macrophages (CRMs) are integral components of the heart and play significant roles in cardiac development, steady-state, and injury. Advances in sequencing technology have revealed that CRMs are a highly heterogeneous population, with significant differences in phenotype and function at different developmental stages and locations within the heart. In addition to research focused on diseases, recent years have witnessed a heightened interest in elucidating the involvement of CRMs in heart development and the maintenance of cardiac function. In this review, we primarily concentrated on summarizing the developmental trajectories, both spatial and temporal, of CRMs and their impact on cardiac development and steady-state. Moreover, we discuss the possible factors by which the cardiac microenvironment regulates macrophages from the perspectives of migration, proliferation, and differentiation under physiological conditions. Gaining insight into the spatiotemporal heterogeneity and regulatory mechanisms of CRMs is of paramount importance in comprehending the involvement of macrophages in cardiac development, injury, and repair, and also provides new ideas and therapeutic methods for treating heart diseases.
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Affiliation(s)
- Demeng Qin
- Institute of Hematological Disease, Jiangsu University, Zhenjiang, China
- International Genome Center, Jiangsu University, Zhenjiang, China
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Fang Liu
- International Genome Center, Jiangsu University, Zhenjiang, China
- Institute of Medical Immunology, Jiangsu University, Zhenjiang, China
| | - Xiang Xu
- Department of Business, Yancheng Blood Center, Yancheng, China
| | - Haiqiang Jiang
- Department of Laboratory Medicine, Jiangyin Hospital of Traditional Chinese Medicine, Wuxi, China
| | - Zhaoliang Su
- International Genome Center, Jiangsu University, Zhenjiang, China
- Institute of Medical Immunology, Jiangsu University, Zhenjiang, China
| | - Lin Xia
- Institute of Hematological Disease, Jiangsu University, Zhenjiang, China
- International Genome Center, Jiangsu University, Zhenjiang, China
- Department of Laboratory Medicine, Affiliated Hospital of Jiangsu University, Zhenjiang, China
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2
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Lieffrig SA, Gyimesi G, Mao Y, Finnemann SC. Clearance phagocytosis by the retinal pigment epithelial during photoreceptor outer segment renewal: Molecular mechanisms and relation to retinal inflammation. Immunol Rev 2023; 319:81-99. [PMID: 37555340 PMCID: PMC10615845 DOI: 10.1111/imr.13264] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/18/2023] [Indexed: 08/10/2023]
Abstract
Mammalian photoreceptor outer segment renewal is a highly coordinated process that hinges on timed cell signaling between photoreceptor neurons and the adjacent retinal pigment epithelial (RPE). It is a strictly rhythmic, synchronized process that underlies in part circadian regulation. We highlight findings from recently developed methods that quantify distinct phases of outer segment renewal in retinal tissue. At light onset, outer segments expose the conserved "eat-me" signal phosphatidylserine exclusively at their distal, most aged tip. A coordinated two-receptor efferocytosis process follows, in which ligands bridge outer segment phosphatidylserine with the RPE receptors αvβ5 integrin, inducing cytosolic signaling toward Rac1 and focal adhesion kinase/MERTK, and with MERTK directly, additionally inhibiting RhoA/ROCK and thus enabling F-actin dynamics favoring outer segment fragment engulfment. Photoreceptors and RPE persist for life with each RPE cell in the eye servicing dozens of overlying photoreceptors. Thus, RPE cells phagocytose more often and process more material than any other cell type. Mutant mice with impaired outer segment renewal largely retain functional photoreceptors and retinal integrity. However, when anti-inflammatory signaling in the RPE via MERTK or the related TYRO3 is lacking, catastrophic inflammation leads to immune cell infiltration that swiftly destroys the retina causing blindness.
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Affiliation(s)
- Stephanie A. Lieffrig
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
| | - Gavin Gyimesi
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
| | | | - Silvia C. Finnemann
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham University, Bronx, NY
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3
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Tajbakhsh A, Gheibihayat SM, Karami N, Savardashtaki A, Butler AE, Rizzo M, Sahebkar A. The regulation of efferocytosis signaling pathways and adipose tissue homeostasis in physiological conditions and obesity: Current understanding and treatment options. Obes Rev 2022; 23:e13487. [PMID: 35765849 DOI: 10.1111/obr.13487] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/14/2022]
Abstract
Obesity is associated with changes in the resolution of acute inflammation that contribute to the clinical complications. The exact mechanisms underlying unresolved inflammation in obesity are not fully understood. Adipocyte death leads to pro-inflammatory adipose tissue macrophages, stimulating additional adipocyte apoptosis. Thus, a complex and tightly regulated process to inhibit inflammation and maintain homeostasis after adipocyte apoptosis is needed to maintain health. In normal condition, a specialized phagocytic process (efferocytosis) performs this function, clearing necrotic and apoptotic cells (ACs) and controlling inflammation. For efficient and continued efferocytosis, phagocytes must internalize multiple ACs in physiological conditions and handle the excess metabolic burden in adipose tissue. In obesity, this control is lost and can be an important hallmark of the disease. In this regard, the deficiency of efferocytosis leads to delayed resolution of acute inflammation and can result in ongoing inflammation, immune system dysfunction, and insulin resistance in obesity. Hence, efficient clearance of ACs by M2 macrophages could limit long-term inflammation and ensue clinical complications, such as cardiovascular disease and diabetes. This review elaborates upon the molecular mechanisms to identify efferocytosis regulators in obesity, and the mechanisms that can improve efferocytosis and reduce obesity-related complications, such as the use of pharmacological agents and regular exercise.
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Affiliation(s)
- Amir Tajbakhsh
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Seyed Mohammad Gheibihayat
- Department of Medical Biotechnology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Neda Karami
- Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Savardashtaki
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran.,Infertility Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Alexandra E Butler
- Research Department, Royal College of Surgeons in Ireland Bahrain, Adliya, 15503, Bahrain
| | - Manfredi Rizzo
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, School of Medicine, University of Palermo, Palermo, Italy
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,School of Medicine, The University of Western Australia, Perth, Western Australia, Australia.,Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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4
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Bellinge JW, Francis RJ, Lee SC, Vickery A, Macdonald W, Gan SK, Chew GT, Phillips M, Lewis JR, Watts GF, Schultz CJ. The effect of Vitamin-K 1 and Colchicine on Vascular Calcification Activity in subjects with Diabetes Mellitus (ViKCoVaC): A double-blind 2x2 factorial randomized controlled trial. J Nucl Cardiol 2022; 29:1855-1866. [PMID: 33825140 DOI: 10.1007/s12350-021-02589-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 02/03/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND There is currently no treatment for attenuating progression of arterial calcification. 18F-sodium fluoride positron emission tomography (18F-NaF PET) locates regions of calcification activity. We tested whether vitamin-K1 or colchicine affected arterial calcification activity. METHODS 154 patients with diabetes mellitus and coronary calcification, as detected using computed tomography (CT), were randomized to one of four treatment groups (placebo/placebo, vitamin-K1 [10 mg/day]/placebo, colchicine [0.5 mg/day]/placebo, vitamin-K1 [10 mg/day]/ colchicine [0.5 mg/day]) in a double-blind, placebo-controlled 2x2 factorial trial of three months duration. Change in coronary calcification activity was estimated as a change in coronary maximum tissue-to-background ratio (TBRmax) on 18F-NaF PET. RESULTS 149 subjects completed follow-up (vitamin-K1: placebo = 73:76 and colchicine: placebo = 73:76). Neither vitamin-K1 nor colchicine had a statistically significant effect on the coronary TBRmax compared with placebo (mean difference for treatment groups 0·00 ± 0·16 and 0·01 ± 0·17, respectively, p > 0.05). There were no serious adverse effects reported with colchicine or vitamin-K1. CONCLUSIONS In patients with type 2 diabetes, neither vitamin-K1 nor colchicine significantly decreases coronary calcification activity, as estimated by 18F-NaF PET, over a period of 3 months. CLINICAL TRIAL REGISTRATION ACTRN12616000024448.
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Affiliation(s)
- Jamie W Bellinge
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Department of Cardiology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Roslyn J Francis
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Department of Nuclear Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Sing Ching Lee
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Department of Cardiology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Alistair Vickery
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Black Swan Health, Perth, Western Australia, Australia
| | - William Macdonald
- Department of Nuclear Medicine, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Seng Khee Gan
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Department of Endocrinology and Diabetes, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Gerard T Chew
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Department of Endocrinology and Diabetes, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Michael Phillips
- Harry Perkins Institute for Medical Research, and Centre for Medical Research, University of Western Australia and, Nedlands, Western Australia, Australia
| | - Joshua R Lewis
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
- Centre for Kidney Research, Children's Hospital Westmead, School of Public Health, University of Sydney, Westmead, New South Wales, Australia
| | - Gerald F Watts
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia
- Cardiometabolic service, Department of Cardiology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Carl J Schultz
- School of Medicine, Faculty of Health and Biomedical Science, University of Western Australia, Royal Perth Hospital Campus, M570, Po Box X2213, Perth, Western Australia, Australia.
- Department of Cardiology, Royal Perth Hospital, Perth, Western Australia, Australia.
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5
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Qian Y, Shang Z, Gao Y, Wu H, Kong X. Liver Regeneration in Chronic Liver Injuries: Basic and Clinical Applications Focusing on Macrophages and Natural Killer Cells. Cell Mol Gastroenterol Hepatol 2022; 14:971-981. [PMID: 35738473 PMCID: PMC9489753 DOI: 10.1016/j.jcmgh.2022.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/28/2022] [Accepted: 07/27/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND & AIMS Liver regeneration is a necessary but complex process involving multiple cell types besides hepatocytes. Mechanisms underlying liver regeneration after partial hepatectomy and acute liver injury have been well-described. However, in patients with chronic and severe liver injury, the remnant liver cannot completely restore the liver mass and function, thereby involving liver progenitor-like cells (LPLCs) and various immune cells. RESULTS Macrophages are beneficial to LPLCs proliferation and the differentiation of LPLCs to hepatocytes. Also, cells expressing natural killer (NK) cell markers have been studied in promoting both liver injury and liver regeneration. NK cells can promote LPLC-induced liver regeneration, but the excessive activation of hepatic NK cells may lead to high serum levels of interferon-γ, thus inhibiting liver regeneration. CONCLUSIONS This review summarizes the recent research on 2 important innate immune cells, macrophages and NK cells, in LPLC-induced liver regeneration and the mechanisms of liver regeneration during chronic liver injury, as well as the latest macrophage- and NK cell-based therapies for chronic liver injury. These novel findings can further help identify new treatments for chronic liver injury, saving patients from the pain of liver transplantations.
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Affiliation(s)
- Yihan Qian
- Central Laboratory, Department of Liver Diseases, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Zhi Shang
- Central Laboratory, Department of Liver Diseases, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yueqiu Gao
- Central Laboratory, Department of Liver Diseases, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hailong Wu
- Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai, China.
| | - Xiaoni Kong
- Central Laboratory, Department of Liver Diseases, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China.
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6
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Anderson SR, Roberts JM, Ghena N, Irvin EA, Schwakopf J, Cooperstein IB, Bosco A, Vetter ML. Neuronal apoptosis drives remodeling states of microglia and shifts in survival pathway dependence. eLife 2022; 11:e76564. [PMID: 35481836 PMCID: PMC9071266 DOI: 10.7554/elife.76564] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/27/2022] [Indexed: 01/13/2023] Open
Abstract
Microglia serve critical remodeling roles that shape the developing nervous system, responding to the changing neural environment with phagocytosis or soluble factor secretion. Recent single-cell sequencing (scRNAseq) studies have revealed the context-dependent diversity in microglial properties and gene expression, but the cues promoting this diversity are not well defined. Here, we ask how interactions with apoptotic neurons shape microglial state, including lysosomal and lipid metabolism gene expression and dependence on Colony-stimulating factor 1 receptor (CSF1R) for survival. Using early postnatal mouse retina, a CNS region undergoing significant developmental remodeling, we performed scRNAseq on microglia from mice that are wild-type, lack neuronal apoptosis (Bax KO), or are treated with CSF1R inhibitor (PLX3397). We find that interactions with apoptotic neurons drive multiple microglial remodeling states, subsets of which are resistant to CSF1R inhibition. We find that TAM receptor Mer and complement receptor 3 are required for clearance of apoptotic neurons, but that Mer does not drive expression of remodeling genes. We show TAM receptor Axl is negligible for phagocytosis or remodeling gene expression but is consequential for microglial survival in the absence of CSF1R signaling. Thus, interactions with apoptotic neurons shift microglia toward distinct remodeling states and through Axl, alter microglial dependence on survival pathway, CSF1R.
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Affiliation(s)
| | | | - Nathaniel Ghena
- Department of Neurobiology, University of UtahSalt Lake CityUnited States
- Interdepartmental Program in Neuroscience, University of UtahSalt Lake CityUnited States
| | - Emmalyn A Irvin
- Department of Neurobiology, University of UtahSalt Lake CityUnited States
| | - Joon Schwakopf
- Department of Neurobiology, University of UtahSalt Lake CityUnited States
| | | | - Alejandra Bosco
- Department of Neurobiology, University of UtahSalt Lake CityUnited States
| | - Monica L Vetter
- Department of Neurobiology, University of UtahSalt Lake CityUnited States
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7
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Jarai BM, Fromen CA. Nanoparticle Internalization Promotes the Survival of Primary Macrophages. ADVANCED NANOBIOMED RESEARCH 2022; 2. [PMID: 35991157 PMCID: PMC9387674 DOI: 10.1002/anbr.202100127] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macrophages, a class of tissue resident innate immune cells, are responsible for sequestering foreign objects through the process of phagocytosis, making them a promising target for immune-modulation via particulate engineering. Here, we report that nanoparticle (NP) dosing and cellular internalization via phagocytosis significantly enhances survival of ex vivo cultures of primary bone marrow-derived, alveolar, and peritoneal macrophages over particle-free controls. The enhanced survival is attributed to suppression of caspase-dependent apoptosis and is linked to phagocytosis and lysosomal signaling. Uniquely, poly(ethylene glycol)-based NP treatment extended cell viability in the absence of macrophage polarization and enhanced expression of pro-survival B cell lymphoma-2 (Bcl-2) protein in macrophages following multiple routes of in vivo administration. The enhanced survival phenomenon is also applicable to NPs of alternative chemistries, indicating the potential universality of this phenomenon with relevant drug delivery particles. These findings provide a framework for extending the lifespan of primary macrophages ex vivo for drug screening, vaccine studies, and cell therapies and has implications for any in vivo particulate immune-engineering applications.
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Affiliation(s)
- Bader M. Jarai
- Department of Chemical and Biomolecular Engineering University of Delaware 150 Academy St. Newark DE 19716 USA
| | - Catherine A. Fromen
- Department of Chemical and Biomolecular Engineering University of Delaware 150 Academy St. Newark DE 19716 USA
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8
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Efferocytosis induces macrophage proliferation to help resolve tissue injury. Cell Metab 2021; 33:2445-2463.e8. [PMID: 34784501 PMCID: PMC8665147 DOI: 10.1016/j.cmet.2021.10.015] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/17/2021] [Accepted: 10/26/2021] [Indexed: 01/01/2023]
Abstract
Apoptotic cell clearance by macrophages (efferocytosis) promotes resolution signaling pathways, which can be triggered by molecules derived from the phagolysosomal degradation of apoptotic cells. We show here that nucleotides derived from the hydrolysis of apoptotic cell DNA by phagolysosomal DNase2a activate a DNA-PKcs-mTORC2/Rictor pathway that increases Myc to promote non-inflammatory macrophage proliferation. Efferocytosis-induced proliferation expands the pool of resolving macrophages in vitro and in mice, including zymosan-induced peritonitis, dexamethasone-induced thymocyte apoptosis, and atherosclerosis regression. In the dexamethasone-thymus model, hematopoietic Rictor deletion blocked efferocytosing macrophage proliferation, apoptotic cell clearance, and tissue resolution. In atherosclerosis regression, silencing macrophage Rictor or DNase2a blocked efferocyte proliferation, apoptotic cell clearance, and plaque stabilization. In view of previous work showing that other types of apoptotic cell cargo can promote resolution in individual efferocytosing macrophages, the findings here suggest that signaling-triggered apoptotic cell-derived nucleotides can amplify this benefit by increasing the number of these macrophages.
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9
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Jarai BM, Stillman Z, Fromen CA. Hydrogel nanoparticle degradation influences the activation and survival of primary macrophages. J Mater Chem B 2021; 9:7246-7257. [PMID: 34226910 PMCID: PMC8446340 DOI: 10.1039/d1tb00982f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effect of nanoparticle (NP) internalization on cell fate has emerged as an important consideration for nanomedicine design, as macrophages and other phagocytes are the primary clearance mechanisms of administered NP formulations. Pro-survival signaling is thought to be concurrent with phagocytosis and recent work has shown increased macrophage survival following lysosomal processing of internalized NPs. These observations have opened the door to explorations of NP physiochemical properties aimed at tuning the NP-driven macrophage survival at the lysosomal synapse. Here, we report that NP-induced macrophage survival and activation is strongly dependent on NP degradation rate using a series of thiol-containing poly(ethylene glycol) diacrylate-based NPs of equivalent size and zeta potential. Rapidly degrading, high thiol-containing NPs allowed for dramatic enhancement of cell longevity that was concurrent with macrophage stimulation after 2 weeks in ex vivo culture. While equivalent NP internalization resulted in suppressed caspase activity across the NP series, macrophage activation was correlated with increasing thiol content, leading to increased lysosomal activity and a robust pro-survival phenotype. Our results provide insight on tuning NP physiochemical properties as design handles for maximizing ex vivo macrophage longevity, which has implications for improving macrophage-based immune assays, biomanufacturing, and cell therapies.
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Affiliation(s)
- Bader M Jarai
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St., Newark, DE 19716, USA.
| | - Zachary Stillman
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St., Newark, DE 19716, USA.
| | - Catherine A Fromen
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St., Newark, DE 19716, USA.
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10
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Rasheed A, Rayner KJ. Macrophage Responses to Environmental Stimuli During Homeostasis and Disease. Endocr Rev 2021; 42:407-435. [PMID: 33523133 PMCID: PMC8284619 DOI: 10.1210/endrev/bnab004] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 12/20/2022]
Abstract
Work over the last 40 years has described macrophages as a heterogeneous population that serve as the frontline surveyors of tissue immunity. As a class, macrophages are found in almost every tissue in the body and as distinct populations within discrete microenvironments in any given tissue. During homeostasis, macrophages protect these tissues by clearing invading foreign bodies and/or mounting immune responses. In addition to varying identities regulated by transcriptional programs shaped by their respective environments, macrophage metabolism serves as an additional regulator to temper responses to extracellular stimuli. The area of research known as "immunometabolism" has been established within the last decade, owing to an increase in studies focusing on the crosstalk between altered metabolism and the regulation of cellular immune processes. From this research, macrophages have emerged as a prime focus of immunometabolic studies, although macrophage metabolism and their immune responses have been studied for centuries. During disease, the metabolic profile of the tissue and/or systemic regulators, such as endocrine factors, become increasingly dysregulated. Owing to these changes, macrophage responses can become skewed to promote further pathophysiologic changes. For instance, during diabetes, obesity, and atherosclerosis, macrophages favor a proinflammatory phenotype; whereas in the tumor microenvironment, macrophages elicit an anti-inflammatory response to enhance tumor growth. Herein we have described how macrophages respond to extracellular cues including inflammatory stimuli, nutrient availability, and endocrine factors that occur during and further promote disease progression.
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Affiliation(s)
- Adil Rasheed
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada.,Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Katey J Rayner
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada.,Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
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11
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Resolution-Associated Lactoferrin Peptides Limit LPS Signaling and Cytokine Secretion from Human Macrophages. Int J Mol Sci 2020; 21:ijms21145166. [PMID: 32708308 PMCID: PMC7404327 DOI: 10.3390/ijms21145166] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 01/01/2023] Open
Abstract
The neutrophil granule protein lactoferrin is cleaved and accumulates in efferocytic macrophages as inflammation is resolved. Two peptides present within a resolution-associated 17 kDa fragment of lactoferrin promote the termination of inflammation in vivo by enhancing murine macrophage reprogramming. Here, we report that these two bioactive tripeptides, phenylalanine-lysine-aspartic acid and phenylalanine-lysine-glutamic acid (FKD and FKE, respectively), inhibit ERK and cJun activation following human macrophage exposure to LPS. In addition, these peptides at low concentrations (1–10 μM) modulate human macrophage reprogramming to an anti-inflammatory/pro-resolving phenotype. This was reflected by inhibition of LPS-induced TNF-α and IL-6 secretion and increased IL-10 levels. Moreover, we found naturally occurring FKE analogs (FKECH and FKECHLA) can recapitulate the activity of the short peptide in regulating macrophage cytokine secretion, whereas a reversed EKF peptide was inert in this respect. Curiously, FKD and FKE also regulated cytokine production by bone marrow-derived mouse macrophages, but in a very different fashion than their effect on human macrophages. Thus, lactoferrin peptides limit pro-inflammatory signaling and cytokine production by LPS-activated human macrophages and thereby enhance the resolution of inflammation.
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12
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Biological profile of monocyte-derived macrophages in coronary heart disease patients: implications for plaque morphology. Sci Rep 2019; 9:8680. [PMID: 31213640 PMCID: PMC6581961 DOI: 10.1038/s41598-019-44847-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 05/24/2019] [Indexed: 02/06/2023] Open
Abstract
The prevalence of a macrophage phenotype in atherosclerotic plaque may drive its progression and/or instability. Macrophages from coronary plaques are not available, and monocyte-derived macrophages (MDMs) are usually considered as a surrogate. We compared the MDM profile obtained from coronary artery disease (CAD) patients and healthy subjects, and we evaluated the association between CAD MDM profile and in vivo coronary plaque characteristics assessed by optical coherence tomography (OCT). At morphological analysis, MDMs of CAD patients had a higher prevalence of round than spindle cells, whereas in healthy subjects the prevalence of the two morphotypes was similar. Compared to healthy subjects, MDMs of CAD patients had reduced efferocytosis, lower transglutaminase-2, CD206 and CD163 receptor levels, and higher tissue factor (TF) levels. At OCT, patients with a higher prevalence of round MDMs showed more frequently a lipid-rich plaque, a thin-cap fibroatheroma, a greater intra-plaque macrophage accumulation, and a ruptured plaque. The MDM efferocytosis correlated with minimal lumen area, and TF levels in MDMs correlated with the presence of ruptured plaque. MDMs obtained from CAD patients are characterized by a morpho-phenotypic heterogeneity with a prevalence of round cells, showing pro-inflammatory and pro-thrombotic properties. The MDM profile allows identifying CAD patients at high risk.
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13
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Iida J, Ishii S, Nakajima Y, Sessler DI, Teramae H, Kageyama K, Maeda S, Anada N, Shibasaki M, Sawa T, Nakayama Y. Hyperglycaemia augments lipopolysaccharide-induced reduction in rat and human macrophage phagocytosis via the endoplasmic stress-C/EBP homologous protein pathway. Br J Anaesth 2019; 123:51-59. [PMID: 31084986 DOI: 10.1016/j.bja.2019.03.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Macrophage phagocytosis constitutes an essential part of the host defence against microbes and the resolution of inflammation. Hyperglycaemia during sepsis is reported to reduce macrophage function, and thus, potentiate inflammatory deterioration. We investigated whether high-glucose concentrations augment lipopolysaccharide-induced reduction in macrophage phagocytosis via the endoplasmic stress-C/EBP homologous protein (CHOP) pathway using animal and laboratory investigations. METHODS Peritoneal macrophages of artificially ventilated male Wistar rats, divided into four groups based on target blood glucose concentrations achieved by glucose administration with or without lipopolysaccharide, were obtained after 24 h. Human macrophages were also cultured in normal or high glucose with or without lipopolysaccharide exposure for 72 h. Changes in the phagocytic activity, intranuclear CHOP expression, and intracellular Akt phosphorylation status of macrophages were evaluated. These changes were also evaluated in human macrophages after genetic knock-down of CHOP by specific siRNA transfection or resolvin D2 treatment. RESULTS Lipopolysaccharide impaired phagocytosis, increased intranuclear expression of CHOP, and inhibited Akt phosphorylation in both rat peritoneal and human macrophages. Hyperglycaemic glucose concentrations augmented these changes. Genetic knock-down of CHOP restored phagocytic ability and Akt phosphorylation in human macrophages. Furthermore, resolvin D2 co-incubation restored the inhibited phagocytosis and Akt phosphorylation along with the inhibition of intranuclear CHOP expression in human macrophages. CONCLUSIONS These findings imply that controlling endoplasmic reticulum stress might provide new strategies for restoring reduced macrophage phagocytosis in sepsis-induced hyperglycaemia.
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Affiliation(s)
- J Iida
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - S Ishii
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Y Nakajima
- Department of Anesthesiology and Critical Care, Kansai Medical University, Osaka, Japan.
| | - D I Sessler
- Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, OH, USA
| | - H Teramae
- Faculty of Teacher Education, Shumei University, Chiba, Japan
| | - K Kageyama
- Department of Anesthesiology and Critical Care, Kansai Medical University, Osaka, Japan
| | - S Maeda
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - N Anada
- Department of Anesthesiology and Critical Care, Kansai Medical University, Osaka, Japan
| | - M Shibasaki
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - T Sawa
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Y Nakayama
- Department of Anesthesiology and Critical Care, Kyoto Prefectural University of Medicine, Kyoto, Japan
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14
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Voices from the dead: The complex vocabulary and intricate grammar of dead cells. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:1-90. [PMID: 31036289 DOI: 10.1016/bs.apcsb.2019.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Of the roughly one million cells per second dying throughout the body, the vast majority dies by apoptosis, the predominant form of regulated cell death in higher organisms. Long regarded as mere waste, apoptotic cells are now recognized as playing a prominent and active role in homeostatic maintenance, especially resolution of inflammation, and in the sculpting of tissues during development. The activities associated with apoptotic cells are continually expanding, with more recent studies demonstrating their ability to modulate such vital functions as proliferation, survival, differentiation, metabolism, migration, and angiogenesis. In each case, the role of apoptotic cells is active, exerting their effects via new activities acquired during the apoptotic program. Moreover, the capacity to recognize and respond to apoptotic cells is not limited to professional phagocytes. Most, if not all, cells receive and integrate an array of signals from cells dying in their vicinity. These signals comprise a form of biochemical communication. As reviewed in this chapter, this communication is remarkably sophisticated; each of its three critical steps-encoding, transmission, and decoding of the apoptotic cell's "message"-is endowed with exquisite robustness. Together, the abundance and intricacy of the variables at each step comprise the vocabulary and grammar of the language by which dead cells achieve their post-mortem voice. The combinatorial complexity of the resulting communication network permits dying cells, through the signals they emit and the responses those signals elicit, to partake of an expanded role in homeostasis, acting as both sentinels of environmental change and agents of adaptation.
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15
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Tajbakhsh A, Gheibi Hayat SM, Butler AE, Sahebkar A. Effect of soluble cleavage products of important receptors/ligands on efferocytosis: Their role in inflammatory, autoimmune and cardiovascular disease. Ageing Res Rev 2019; 50:43-57. [PMID: 30639340 DOI: 10.1016/j.arr.2019.01.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/04/2019] [Accepted: 01/08/2019] [Indexed: 12/17/2022]
Abstract
Efferocytosis, the clearance of apoptotic cells (ACs), is a physiologic, multifaceted and dynamic process and a fundamental mechanism for the preservation of tissue homeostasis by avoiding unwanted inflammation and autoimmune responses through special phagocytic receptors. Defective efferocytosis is associated with several disease states, including cardiovascular disease and impaired immune surveillance, as occurs in cancer and autoimmune disease. A major cause of defective efferocytosis is non-functionality of surface receptors on either the phagocytic cells or the ACs, such as TAM family tyrosine kinase, which turns to a soluble form by cleavage/shedding or alternative splicing. Recently, soluble forms have featured prominently as potential biomarkers, indicative of prognosis and enabling targeted therapy using several commonly employed drugs and inhibitors, such as bleomycin, dexamethasone, statins and some matrix metalloproteinase inhibitors such as TAPI-1 and BB3103. Importantly, to design drug carriers with enhanced circulatory durability, the adaptation of soluble forms of physiological receptors/ligands has been purported. Research has shown that soluble forms are more effective than antibody forms in enabling targeted treatment of certain conditions, such as autoimmune diseases. In this review, we sought to summarize the current knowledge of these soluble products, how they are generated, their interactions, roles, and their potential use as biomarkers in prognosis and treatment related to inflammatory, cardiovascular, and autoimmune diseases.
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Affiliation(s)
- Amir Tajbakhsh
- Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Alexandra E Butler
- Diabetes Research Center, Qatar Biomedical Research Institute, Doha, Qatar
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
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16
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Röszer T. Understanding the Biology of Self-Renewing Macrophages. Cells 2018; 7:cells7080103. [PMID: 30096862 PMCID: PMC6115929 DOI: 10.3390/cells7080103] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/02/2018] [Accepted: 08/08/2018] [Indexed: 12/21/2022] Open
Abstract
Macrophages reside in specific territories in organs, where they contribute to the development, homeostasis, and repair of tissues. Recent work has shown that the size of tissue macrophage populations has an impact on tissue functions and is determined by the balance between replenishment and elimination. Macrophage replenishment is mainly due to self-renewal of macrophages, with a secondary contribution from blood monocytes. Self-renewal is a recently discovered trait of macrophages, which can have a major impact on their physiological functions and hence on the wellbeing of the organism. In this review, I discuss our current understanding of the developmental origin of self-renewing macrophages and the mechanisms used to maintain a physiologically stable macrophage pool.
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Affiliation(s)
- Tamás Röszer
- Institute of Neurobiology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
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17
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Tajbakhsh A, Rezaee M, Kovanen PT, Sahebkar A. Efferocytosis in atherosclerotic lesions: Malfunctioning regulatory pathways and control mechanisms. Pharmacol Ther 2018; 188:12-25. [DOI: 10.1016/j.pharmthera.2018.02.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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18
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Feng L, Vujicic S, Dietrich ME, Litbarg N, Setty S, Antoni A, Rauch J, Levine JS. Repeated exposure of epithelial cells to apoptotic cells induces the specific selection of an adaptive phenotype: Implications for tumorigenesis. J Biol Chem 2018; 293:10245-10263. [PMID: 29769319 DOI: 10.1074/jbc.ra117.001290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 05/08/2018] [Indexed: 11/06/2022] Open
Abstract
The consequences of apoptosis extend beyond the mere death of the cell. We have shown that receptor-mediated recognition of apoptotic target cells by viable kidney proximal tubular epithelial cells (PTECs) inhibits PTEC proliferation, growth, and survival. Here, we tested the hypothesis that continual exposure to apoptotic targets can induce a phenotypic change in responding PTECs, as in other instances of natural selection. In particular, we demonstrate that repeated exposure to apoptotic targets leads to emergence of a PTEC line (denoted BU.MPTSEL) resistant to apoptotic target-induced death. Resistance is exquisitely specific. Not only are BU.MPTSEL responders fully resistant to apoptotic target-induced death (∼85% survival versus <10% survival of nonselected cells) but do so while retaining sensitivity to all other target-induced responses, including inhibition of proliferation and growth. Moreover, the resistance of BU.MPTSEL responders is specific to target-induced apoptosis, as apoptosis in response to other suicidal stimuli occurs normally. Comparison of the signaling events induced by apoptotic target exposure in selected versus nonselected responders indicated that the acquired resistance of BU.MPTSEL cells lies in a regulatory step affecting the generation of the pro-apoptotic protein, truncated BH3 interacting-domain death agonist (tBID), most likely at the level of BID cleavage by caspase-8. This specific adaptation has especial relevance for cancer, in which the prominence and persistence of cell death entail magnification of the post-mortem effects of apoptotic cells. Just as cancer cells acquire specific resistance to chemotherapeutic agents, we propose that cancer cells may also adapt to their ongoing exposure to apoptotic targets.
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Affiliation(s)
- Lanfei Feng
- From the Section of Nephrology, Department of Medicine, and.,the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Snezana Vujicic
- From the Section of Nephrology, Department of Medicine, and.,the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | | | - Natalia Litbarg
- From the Section of Nephrology, Department of Medicine, and.,the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Suman Setty
- Department of Pathology, University of Illinois, Chicago, Illinois 60612
| | - Angelika Antoni
- the Department of Biology, Kutztown University of Pennsylvania, Kutztown, Pennsylvania 19530, and
| | - Joyce Rauch
- the Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada
| | - Jerrold S Levine
- From the Section of Nephrology, Department of Medicine, and .,the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
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19
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Abstract
Within an organism, environmental stresses can trigger cell death, particularly apoptotic cell death. Apoptotic cells, themselves, are potent regulators of their cellular environment, involved primarily in effecting homeostatic control. Tumors, especially, exist in a dynamic balance of cell proliferation and cell death. This special feature of the tumorous microenvironment—namely, the prominence and persistence of cell death—necessarily entails a magnification of the extrinsic, postmortem effects of dead cells. In both normal and malignant tissues, apoptotic regulation is exerted through immune as well as non-immune mechanisms. Apoptotic cells suppress the repertoire of immune reactivities, both by attenuating innate (especially inflammatory) responses and by abrogating adaptive responses. In addition, apoptotic cells modulate multiple vital cell activities, including survival, proliferation (cell number), and growth (cell size). While the microenvironment of the tumor may contribute to apoptosis, the postmortem effects of apoptotic cells feature prominently in the reciprocal acclimatization between the tumor and its environment. In much the same way that pathogens evade the host’s defenses through exploitation of key aspects of innate and adaptive immunity, cancer cells subvert several normal homeostatic processes, in particular wound healing and organ regeneration, to transform and overtake their environment. In understanding this subversion, it is crucial to view a tumor not simply as a clone of malignant cells, but rather as a complex and highly organized structure in which there exists a multidirectional flow of information between the cancer cells themselves and the multiple other cell types and extracellular matrix components of which the tumor is comprised. Apoptotic cells, therefore, have the unfortunate consequence of facilitating tumorigenesis and tumor survival.
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Affiliation(s)
- David S Ucker
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL, United States
| | - Jerrold S Levine
- Department of Medicine, Division of Nephrology, University of Illinois College of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, United States
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20
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Aswad M, Assi S, Schif-Zuck S, Ariel A. CCL5 Promotes Resolution-Phase Macrophage Reprogramming in Concert with the Atypical Chemokine Receptor D6 and Apoptotic Polymorphonuclear Cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2017; 199:1393-1404. [PMID: 28674178 DOI: 10.4049/jimmunol.1502542] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 06/07/2017] [Indexed: 12/16/2023]
Abstract
The engulfment of apoptotic polymorphonuclear cells (PMN) during the resolution of inflammation leads to macrophage reprogramming culminating in reduced proinflammatory and increased anti-inflammatory mediator secretion. The atypical chemokine receptor D6/ACKR2 is expressed on apoptotic PMN and plays an important role in regulating macrophage properties during and after engulfment. In this study, we found that the inflammatory chemokine CCL5 is mostly retained (75%) during the resolution of zymosan A peritonitis in mice. Moreover, this chemokine is secreted by resolution-phase macrophages (2.5 ng/ml) and promotes their reprogramming in vivo in D6+/+ mice (2-fold increase in IL-10/IL-12 ratio) but not their D6-/- counterparts. In addition, CCL5 enhanced macrophage reprogramming ex vivo exclusively when bound to D6+/+ apoptotic PMN. Signaling through p38MAPK and JNK in reprogrammed macrophages was enhanced by CCL5-bound apoptotic PMN (3.6-4 fold) in a D6-dependent manner, and was essential for reprogramming. Thus, CCL5 exerts a novel proresolving role on macrophages when acting in concert with apoptotic PMN-expressed D6.
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Affiliation(s)
- Miran Aswad
- Department of Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; and
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
| | - Simaan Assi
- Department of Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; and
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
| | - Sagie Schif-Zuck
- Department of Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; and
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
| | - Amiram Ariel
- Department of Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel; and
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
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21
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Linton MF, Tao H, Linton EF, Yancey PG. SR-BI: A Multifunctional Receptor in Cholesterol Homeostasis and Atherosclerosis. Trends Endocrinol Metab 2017; 28:461-472. [PMID: 28259375 PMCID: PMC5438771 DOI: 10.1016/j.tem.2017.02.001] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 02/07/2023]
Abstract
The HDL receptor scavenger receptor class B type I (SR-BI) plays crucial roles in cholesterol homeostasis, lipoprotein metabolism, and atherosclerosis. Hepatic SR-BI mediates reverse cholesterol transport (RCT) by the uptake of HDL cholesterol for routing to the bile. Through the selective uptake of HDL lipids, hepatic SR-BI modulates HDL composition and preserves HDL's atheroprotective functions of mediating cholesterol efflux and minimizing inflammation and oxidation. Macrophage and endothelial cell SR-BI inhibits the development of atherosclerosis by mediating cholesterol trafficking to minimize atherosclerotic lesion foam cell formation. SR-BI signaling also helps limit inflammation and cell death and mediates efferocytosis of apoptotic cells in atherosclerotic lesions thereby preventing vulnerable plaque formation. SR-BI is emerging as a multifunctional therapeutic target to reduce atherosclerosis development.
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Affiliation(s)
- MacRae F Linton
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300, USA; Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232-6300, USA.
| | - Huan Tao
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300, USA
| | - Edward F Linton
- Perelman School of Medicine, University of Pennsylvania, Jordan Medical Education Center, 6th Floor, 3400 Civic Center Blvd, Philadelphia, PA 19104-6055, USA
| | - Patricia G Yancey
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-6300, USA.
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22
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Guo Q, Minnier J, Burchard J, Chiotti K, Spellman P, Schedin P. Physiologically activated mammary fibroblasts promote postpartum mammary cancer. JCI Insight 2017; 2:e89206. [PMID: 28352652 DOI: 10.1172/jci.insight.89206] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Women diagnosed with breast cancer within 5 years of childbirth have poorer prognosis than nulliparous or pregnant women. Weaning-induced breast involution is implicated, as the collagen-rich, immunosuppressive microenvironment of the involuting mammary gland is tumor promotional in mice. To investigate the role of mammary fibroblasts, isolated mammary PDGFRα+ cells from nulliparous and postweaning mice were assessed for activation phenotype and protumorigenic function. Fibroblast activation during involution was evident by increased expression of fibrillar collagens, lysyl oxidase, Tgfb1, and Cxcl12 genes. The ability of mammary tumors to grow in an isogenic, orthotopic transplant model was increased when tumor cells were coinjected with involution-derived compared with nulliparous-derived mammary fibroblasts. Mammary tumors in the involution-fibroblast group had increased Ly6C+ monocytes at the tumor border, and decreased CD8+ T cell infiltration and tumor cell death. Ibuprofen treatment suppressed involution-fibroblast activation and tumor promotional capacity, concurrent with decreases in tumor Ly6C+ monocytes, and increases in intratumoral CD8+ T cell infiltration, granzyme levels, and tumor cell death. In total, our data identify a COX/prostaglandin E2 (PGE2)-dependent activated mammary fibroblast within the involuting mammary gland that displays protumorigenic, immunosuppressive activity, identifying fibroblasts as potential targets for the prevention and treatment of postpartum breast cancer.
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Affiliation(s)
- Qiuchen Guo
- Department of Cell, Developmental and Cancer Biology
| | | | | | - Kami Chiotti
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA
| | - Paul Spellman
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, USA.,Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Pepper Schedin
- Department of Cell, Developmental and Cancer Biology.,Young Women's Breast Cancer Translational Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA
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23
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Brophy ML, Dong Y, Wu H, Rahman HNA, Song K, Chen H. Eating the Dead to Keep Atherosclerosis at Bay. Front Cardiovasc Med 2017; 4:2. [PMID: 28194400 PMCID: PMC5277199 DOI: 10.3389/fcvm.2017.00002] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/12/2017] [Indexed: 12/22/2022] Open
Abstract
Atherosclerosis is the primary cause of coronary heart disease (CHD), ischemic stroke, and peripheral arterial disease. Despite effective lipid-lowering therapies and prevention programs, atherosclerosis is still the leading cause of mortality in the United States. Moreover, the prevalence of CHD in developing countries worldwide is rapidly increasing at a rate expected to overtake those of cancer and diabetes. Prominent risk factors include the hardening of arteries and high levels of cholesterol, which lead to the initiation and progression of atherosclerosis. However, cell death and efferocytosis are critical components of both atherosclerotic plaque progression and regression, yet, few currently available therapies focus on these processes. Thus, understanding the causes of cell death within the atherosclerotic plaque, the consequences of cell death, and the mechanisms of apoptotic cell clearance may enable the development of new therapies to treat cardiovascular disease. Here, we review how endoplasmic reticulum stress and cholesterol metabolism lead to cell death and inflammation, how dying cells affect plaque progression, and how autophagy and the clearance of dead cells ameliorates the inflammatory environment of the plaque. In addition, we review current research aimed at alleviating these processes and specifically targeting therapeutics to the site of the plaque.
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Affiliation(s)
- Megan L Brophy
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Karp Family Research Laboratories, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Yunzhou Dong
- Karp Family Research Laboratories, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital , Boston, MA , USA
| | - Hao Wu
- Karp Family Research Laboratories, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital , Boston, MA , USA
| | - H N Ashiqur Rahman
- Karp Family Research Laboratories, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital , Boston, MA , USA
| | - Kai Song
- Karp Family Research Laboratories, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital , Boston, MA , USA
| | - Hong Chen
- Karp Family Research Laboratories, Vascular Biology Program, Harvard Medical School, Boston Children's Hospital , Boston, MA , USA
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24
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Vujicic S, Feng L, Antoni A, Rauch J, Levine JS. Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death. J Vis Exp 2016. [PMID: 28060335 DOI: 10.3791/54980] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cells dying by apoptosis, also referred to as regulated cell death, acquire multiple new activities that enable them to influence the function of adjacent live cells. Vital activities, such as survival, proliferation, growth, and differentiation, are among the many cellular functions modulated by apoptotic cells. The ability to recognize and respond to apoptotic cells appears to be a universal feature of all cells, regardless of lineage or organ of origination. However, the diversity and complexity of the response to apoptotic cells mandates that great care be taken in dissecting the signaling events and pathways responsible for any particular outcome. In particular, one must distinguish among the multiple mechanisms by which apoptotic cells can influence intracellular signaling pathways within viable responder cells, including: receptor-mediated recognition of the apoptotic cell, release of soluble mediators by the apoptotic cell, and/or engagement of the phagocytic machinery. Here, we provide a protocol for identifying intracellular signaling events that are induced in viable responder cells following their exposure to apoptotic cells. A major advantage of the protocol lies in the attention it pays to dissection of the mechanism by which apoptotic cells modulate signaling events within responding cells. While the protocol is specific for a conditionally immortalized mouse kidney proximal tubular cell line (BU.MPT cells), it is easily adapted to cell lines that are non-epithelial in origin and/or derived from organs other than the kidney. The use of dead cells as a stimulus introduces several unique factors that can hinder the detection of intracellular signaling events. These problems, as well as strategies to minimize or circumvent them, are discussed within the protocol. Application of this protocol should aid our expanding knowledge of the broad influence that dead or dying cells exert on their live neighbors, both in health and in disease.
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Affiliation(s)
- Snezana Vujicic
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago; Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center
| | - Lanfei Feng
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago; Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center
| | | | - Joyce Rauch
- Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre
| | - Jerrold S Levine
- Section of Nephrology, Department of Medicine, University of Illinois at Chicago; Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center; Department of Microbiology & Immunology, University of Illinois at Chicago;
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25
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Seoane PI, Rückerl D, Casaravilla C, Barrios AA, Pittini Á, MacDonald AS, Allen JE, Díaz A. Particles from the Echinococcus granulosus laminated layer inhibit IL-4 and growth factor-driven Akt phosphorylation and proliferative responses in macrophages. Sci Rep 2016; 6:39204. [PMID: 27966637 PMCID: PMC5155279 DOI: 10.1038/srep39204] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/11/2016] [Indexed: 12/23/2022] Open
Abstract
Proliferation of macrophages is a hallmark of inflammation in many type 2 settings including helminth infections. The cellular expansion is driven by the type 2 cytokine interleukin-4 (IL-4), as well as by M-CSF, which also controls homeostatic levels of tissue resident macrophages. Cystic echinococcosis, caused by the tissue-dwelling larval stage of the cestode Echinococcus granulosus, is characterised by normally subdued local inflammation. Infiltrating host cells make contact only with the acellular protective coat of the parasite, called laminated layer, particles of which can be ingested by phagocytic cells. Here we report that a particulate preparation from this layer (pLL) strongly inhibits the proliferation of macrophages in response to IL-4 or M-CSF. In addition, pLL also inhibits IL-4-driven up-regulation of Relm-α, without similarly affecting Chitinase-like 3 (Chil3/Ym1). IL-4-driven cell proliferation and up-regulation of Relm-α are both known to depend on the phosphatidylinositol (PI3K)/Akt pathway, which is dispensable for induction of Chil3/Ym1. Exposure to pLL in vitro inhibited Akt activation in response to proliferative stimuli, providing a potential mechanism for its activities. Our results suggest that the E. granulosus laminated layer exerts some of its anti-inflammatory properties through inhibition of PI3K/Akt activation and consequent limitation of macrophage proliferation.
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Affiliation(s)
- Paula I Seoane
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) e Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Dominik Rückerl
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Cecilia Casaravilla
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) e Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Anabella A Barrios
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) e Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Álvaro Pittini
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) e Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - Andrew S MacDonald
- Manchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, Manchester, UK
| | - Judith E Allen
- Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Alvaro Díaz
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) e Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
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Linton MF, Babaev VR, Huang J, Linton EF, Tao H, Yancey PG. Macrophage Apoptosis and Efferocytosis in the Pathogenesis of Atherosclerosis. Circ J 2016; 80:2259-2268. [PMID: 27725526 DOI: 10.1253/circj.cj-16-0924] [Citation(s) in RCA: 145] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Macrophage apoptosis and the ability of macrophages to clean up dead cells, a process called efferocytosis, are crucial determinants of atherosclerosis lesion progression and plaque stability. Environmental stressors initiate endoplasmic reticulum (ER) stress and activate the unfolded protein response (UPR). Unresolved ER stress with activation of the UPR initiates apoptosis. Macrophages are resistant to apoptotic stimuli, because of activity of the PI3K/Akt pathway. Macrophages express 3 Akt isoforms, Akt1, Akt2 and Akt3, which are products of distinct but homologous genes. Akt displays isoform-specific effects on atherogenesis, which vary with different vascular cell types. Loss of macrophage Akt2 promotes the anti-inflammatory M2 phenotype and reduces atherosclerosis. However, Akt isoforms are redundant with regard to apoptosis. c-Jun NH2-terminal kinase (JNK) is a pro-apoptotic effector of the UPR, and the JNK1 isoform opposes anti-apoptotic Akt signaling. Loss of JNK1 in hematopoietic cells protects macrophages from apoptosis and accelerates early atherosclerosis. IκB kinase α (IKKα, a member of the serine/threonine protein kinase family) plays an important role in mTORC2-mediated Akt signaling in macrophages, and IKKα deficiency reduces macrophage survival and suppresses early atherosclerosis. Efferocytosis involves the interaction of receptors, bridging molecules, and apoptotic cell ligands. Scavenger receptor class B type I is a critical mediator of macrophage efferocytosis via the Src/PI3K/Rac1 pathway in atherosclerosis. Agonists that resolve inflammation offer promising therapeutic potential to promote efferocytosis and prevent atherosclerotic clinical events. (Circ J 2016; 80: 2259-2268).
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Affiliation(s)
- MacRae F Linton
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center
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27
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Penberthy KK, Ravichandran KS. Apoptotic cell recognition receptors and scavenger receptors. Immunol Rev 2016; 269:44-59. [PMID: 26683144 DOI: 10.1111/imr.12376] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Phosphatidylserine recognition receptors are a highly diverse set of receptors grouped by their ability to recognize the 'eat-me' signal phosphatidylserine on apoptotic cells. Most of the phosphatidylserine recognition receptors dampen inflammation by inducing the production of anti-inflammatory mediators during the phagocytosis of apoptotic corpses. However, many phosphatidylserine receptors are also capable of recognizing other ligands, with some receptors being categorized as scavenger receptors. It is now appreciated that these receptors can elicit different downstream events for particular ligands. Therefore, how phosphatidylserine recognition receptors mediate specific signals during recognition of apoptotic cells versus other ligands, and how this might help regulate the inflammatory state of a tissue is an important question that is not fully understood. Here, we revisit the work on signaling downstream of the phosphatidylserine recognition receptor BAI1, and evaluate how these and other signaling modules mediate signaling downstream from other receptors, including Stabilin-2, MerTK, and αvβ5. We also propose the concept that phosphatidylserine recognition receptors could be viewed as a subset of scavenger receptors that are capable of eliciting anti-inflammatory responses to apoptotic cells.
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Affiliation(s)
- Kristen K Penberthy
- Department of Microbiology, Immunology, and Cancer Biology, Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
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Chen N, Collier MA, Gallovic MD, Collins GC, Sanchez CC, Fernandes EQ, Bachelder EM, Ainslie KM. Degradation of acetalated dextran can be broadly tuned based on cyclic acetal coverage and molecular weight. Int J Pharm 2016; 512:147-157. [PMID: 27543351 DOI: 10.1016/j.ijpharm.2016.08.031] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/09/2016] [Accepted: 08/15/2016] [Indexed: 01/11/2023]
Abstract
Microparticles (MPs) derived from acid-sensitive biopolymers enable rapid degradation and cargo release under acidic conditions, such as at tumor microenvironments, within lysosomal/phagosomal compartments inside phagocytic cells, or at sites of inflammation. One such acid-sensitive biopolymer, acetalated dextran (Ace-DEX), has tunable degradation rates and pH-neutral degradation byproducts consisting of dextran, acetone, and ethanol. By studying the degradation profiles of Ace-DEX MPs with varying cyclic acetal coverage (CAC) and dextran molecular weight (MW), we concluded that MPs composed of low CAC or high MW polymer degraded the fastest at both pH 7.4 and 5.0. To further understand the properties of this unique polymer, we encapsulated a model drug resiquimod, which is a toll-like receptor (TLR) 7/8 agonist, into Ace-DEX MPs of different polymer CAC and dextran MW. It was observed that resiquimod was released faster from MPs of lower CAC or higher MW. By evaluating the activation of RAW macrophages cultured with different types of resiquimod-loaded Ace-DEX MPs, we found that MPs of lower CAC or higher MW promoted greater nitrite production and resulted in more robust cell activation. Our results indicate we can precisely control the degradation profile, release kinetics, and bioactivity of encapsulated cargos by altering CAC and MW, furthering Ace-DEX MPs' novelty as a drug carrier.
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Affiliation(s)
- Naihan Chen
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA
| | - Michael A Collier
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA
| | - Matthew D Gallovic
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA; Department of Chemical and Biomolecular Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Graham C Collins
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA
| | - Carla C Sanchez
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA
| | - Elizabeth Q Fernandes
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA
| | - Eric M Bachelder
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA
| | - Kristy M Ainslie
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, NC, USA.
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Discovering Molecules That Regulate Efferocytosis Using Primary Human Macrophages and High Content Imaging. PLoS One 2015; 10:e0145078. [PMID: 26674639 PMCID: PMC4686065 DOI: 10.1371/journal.pone.0145078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 11/28/2015] [Indexed: 12/20/2022] Open
Abstract
Defective clearance of apoptotic cells can result in sustained inflammation and subsequent autoimmunity. Macrophages, the “professional phagocyte” of the body, are responsible for efficient, non-phlogistic, apoptotic cell clearance. Controlling phagocytosis of apoptotic cells by macrophages is an attractive therapeutic opportunity to ameliorate inflammation. Using high content imaging, we have developed a system for evaluating the effects of antibody treatment on apoptotic cell uptake in primary human macrophages by comparing the Phagocytic Index (PI) for each antibody. Herein we demonstrate the feasibility of evaluating a panel of antibodies of unknown specificities obtained by immunization of mice with primary human macrophages and show that they can be distinguished based on individual PI measurements. In this study ~50% of antibodies obtained enhance phagocytosis of apoptotic cells while approximately 5% of the antibodies in the panel exhibit some inhibition. Though the specificities of the majority of antibodies are unknown, two of the antibodies that improved apoptotic cell uptake recognize recombinant MerTK; a receptor known to function in this capacity in vivo. The agonistic impact of these antibodies on efferocytosis could be demonstrated without addition of either of the MerTK ligands, Gas6 or ProS. These results validate applying the mechanism of this fundamental biological process as a means for identification of modulators that could potentially serve as therapeutics. This strategy for interrogating macrophages to discover molecules regulating apoptotic cell uptake is not limited by access to purified protein thereby increasing the possibility of finding novel apoptotic cell uptake pathways.
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Patel VA, Massenburg D, Vujicic S, Feng L, Tang M, Litbarg N, Antoni A, Rauch J, Lieberthal W, Levine JS. Apoptotic cells activate AMP-activated protein kinase (AMPK) and inhibit epithelial cell growth without change in intracellular energy stores. J Biol Chem 2015; 290:22352-69. [PMID: 26183782 DOI: 10.1074/jbc.m115.667345] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Indexed: 01/21/2023] Open
Abstract
Apoptosis plays an indispensable role in the maintenance and development of tissues. We have shown that receptor-mediated recognition of apoptotic target cells by viable kidney proximal tubular epithelial cells (PTECs) inhibits the proliferation and survival of PTECs. Here, we examined the effect of apoptotic targets on PTEC cell growth (cell size during G1 phase of the cell cycle). Using a cell culture model, we show that apoptotic cells potently activate AMP-activated protein kinase (AMPK), a highly sensitive sensor of intracellular energy stores. AMPK activation leads to decreased activity of its downstream target, ribosomal protein p70 S6 kinase (p70S6K), and concomitant inhibition of cell growth. Importantly, these events occur without detectable change in intracellular levels of AMP, ADP, or ATP. Inhibition of AMPK, either pharmacologically by compound C or molecularly by shRNA, diminishes the effects of apoptotic targets and largely restores p70S6K activity and cell size to normal levels. Apoptotic targets also inhibit Akt, a second signaling pathway regulating cell growth. Expression of a constitutively active Akt construct partially relieved cell growth inhibition but was less effective than inhibition of AMPK. Inhibition of cell growth by apoptotic targets is dependent on physical interaction between apoptotic targets and PTECs but independent of phagocytosis. We conclude that receptor-mediated recognition of apoptotic targets mimics the effects of intracellular energy depletion, activating AMPK and inhibiting cell growth. By acting as sentinels of environmental change, apoptotic death may enable nearby viable cells, especially nonmigratory epithelial cells, to monitor and adapt to local stresses.
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Affiliation(s)
- Vimal A Patel
- From the Section of Nephrology, Departments of Medicine and the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Donald Massenburg
- From the Section of Nephrology, Departments of Medicine and the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Snezana Vujicic
- From the Section of Nephrology, Departments of Medicine and the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Lanfei Feng
- From the Section of Nephrology, Departments of Medicine and the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Meiyi Tang
- the Section of Nephrology, Department of Medicine, Stony Brook University Medical Center, Stony Brook, New York 11794, the Northport Veterans Affairs Hospital, Northport, New York 11768
| | - Natalia Litbarg
- From the Section of Nephrology, Departments of Medicine and the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612
| | - Angelika Antoni
- the Department of Biology, Kutztown University of Pennsylvania, Kutztown, Pennsylvania 19530, and
| | - Joyce Rauch
- the Division of Rheumatology, Department of Medicine, Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada
| | - Wilfred Lieberthal
- the Section of Nephrology, Department of Medicine, Stony Brook University Medical Center, Stony Brook, New York 11794, the Northport Veterans Affairs Hospital, Northport, New York 11768
| | - Jerrold S Levine
- From the Section of Nephrology, Departments of Medicine and the Section of Nephrology, Department of Medicine, Jesse Brown Veterans Affairs Hospital, Chicago, Illinois 60612, Microbiology and Immunology, University of Illinois, Chicago, Illinois 60612,
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Tao H, Yancey PG, Babaev VR, Blakemore JL, Zhang Y, Ding L, Fazio S, Linton MF. Macrophage SR-BI mediates efferocytosis via Src/PI3K/Rac1 signaling and reduces atherosclerotic lesion necrosis. J Lipid Res 2015; 56:1449-60. [PMID: 26059978 PMCID: PMC4513986 DOI: 10.1194/jlr.m056689] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Indexed: 12/13/2022] Open
Abstract
Macrophage apoptosis and efferocytosis are key determinants of atherosclerotic plaque inflammation and necrosis. Bone marrow transplantation studies in ApoE- and LDLR-deficient mice revealed that hematopoietic scavenger receptor class B type I (SR-BI) deficiency results in severely defective efferocytosis in mouse atherosclerotic lesions, resulting in a 17-fold higher ratio of free to macrophage-associated dead cells in lesions containing SR-BI−/− cells, 5-fold more necrosis, 65.2% less lesional collagen content, nearly 7-fold higher dead cell accumulation, and 2-fold larger lesion area. Hematopoietic SR-BI deletion elicited a maladaptive inflammatory response [higher interleukin (IL)-1β, IL-6, and TNF-α lower IL-10 and transforming growth factor β]. Efferocytosis of apoptotic thymocytes was reduced by 64% in SR-BI−/− versus WT macrophages, both in vitro and in vivo. In response to apoptotic cells, macrophage SR-BI bound with phosphatidylserine and induced Src phosphorylation and cell membrane recruitment, which led to downstream activation of phosphoinositide 3-kinase (PI3K) and Ras-related C3 botulinum toxin substrate 1 (Rac1) for engulfment and clearance of apoptotic cells, as inhibition of Src decreased PI3K, Rac1-GTP, and efferocytosis in WT cells. Pharmacological inhibition of Rac1 reduced macrophage efferocytosis in a SR-BI-dependent fashion, and activation of Rac1 corrected the defective efferocytosis in SR-BI−/− macrophages. Thus, deficiency of macrophage SR-BI promotes defective efferocytosis signaling via the Src/PI3K/Rac1 pathway, resulting in increased plaque size, necrosis, and inflammation.
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Affiliation(s)
- Huan Tao
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Patricia G Yancey
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Vladimir R Babaev
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - John L Blakemore
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Youmin Zhang
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Lei Ding
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Sergio Fazio
- Department of Medicine, Physiology, and Pharmacology, Center of Preventive Cardiology, Oregon Health and Science University, Portland, OR 97239
| | - MacRae F Linton
- Department of Medicine, Atherosclerosis Research Unit, Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232 Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232
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32
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Pattabiraman G, Lidstone EA, Palasiewicz K, Cunningham BT, Ucker DS. Recognition of apoptotic cells by viable cells is specific, ubiquitous, and species independent: analysis using photonic crystal biosensors. Mol Biol Cell 2014; 25:1704-14. [PMID: 24694594 PMCID: PMC4038498 DOI: 10.1091/mbc.e13-11-0700] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Apoptotic recognition is innate and linked to a profound immune regulation (innate apoptotic immunity [IAI]) involving anti-inflammatory and immunosuppressive responses. Many of the molecular and mechanistic details of this response remain elusive. Although immune outcomes can be quantified readily, the initial specific recognition events have been difficult to assess. We developed a sensitive, real-time method to detect the recognition of apoptotic cells by viable adherent responder cells, using a photonic crystal biosensor approach. The method relies on characteristic spectral shifts resulting from the specific recognition and dose-dependent interaction of adherent responder cells with nonadherent apoptotic targets. Of note, the biosensor provides a readout of early recognition-specific events in responder cells that occur distal to the biosensor surface. We find that innate apoptotic cell recognition occurs in a strikingly species-independent manner, consistent with our previous work and inferences drawn from indirect assays. Our studies indicate obligate cytoskeletal involvement, although apoptotic cell phagocytosis is not involved. Because it is a direct, objective, and quantitative readout of recognition exclusively, this biosensor approach affords a methodology with which to dissect the early recognition events associated with IAI and immunosuppression.
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Affiliation(s)
- Goutham Pattabiraman
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612
| | - Erich A Lidstone
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Karol Palasiewicz
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612
| | - Brian T Cunningham
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801Cancer Center, University of Illinois College of Medicine, Chicago, IL 60612
| | - David S Ucker
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612Cancer Center, University of Illinois College of Medicine, Chicago, IL 60612Department of Bioengineering, University of Illinois College of Medicine, Chicago, IL 60612
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33
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Osteal macrophages support physiologic skeletal remodeling and anabolic actions of parathyroid hormone in bone. Proc Natl Acad Sci U S A 2014; 111:1545-50. [PMID: 24406853 DOI: 10.1073/pnas.1315153111] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cellular subpopulations in the bone marrow play distinct and unexplored functions in skeletal homeostasis. This study delineated a unique role of osteal macrophages in bone and parathyroid hormone (PTH)-dependent bone anabolism using murine models of targeted myeloid-lineage cell ablation. Depletion of c-fms(+) myeloid lineage cells [via administration of AP20187 in the macrophage Fas-induced apoptosis (MAFIA) mouse model] reduced cortical and trabecular bone mass and attenuated PTH-induced trabecular bone anabolism, supporting the positive function of macrophages in bone homeostasis. Interestingly, using a clodronate liposome model with targeted depletion of mature phagocytic macrophages an opposite effect was found with increased trabecular bone mass and increased PTH-induced anabolism. Apoptotic cells were more numerous in MAFIA versus clodronate-treated mice and flow cytometric analyses of myeloid lineage cells in the bone marrow showed that MAFIA mice had reduced CD68(+) cells, whereas clodronate liposome-treated mice had increased CD68(+) and CD163(+) cells. Clodronate liposomes increased efferocytosis (clearance of apoptotic cells) and gene expression associated with alternatively activated M2 macrophages as well as expression of genes associated with bone formation including Wnt3a, Wnt10b, and Tgfb1. Taken together, depletion of early lineage macrophages resulted in osteopenia with blunted effects of PTH anabolic actions, whereas depletion of differentiated macrophages promoted apoptotic cell clearance and transformed the bone marrow to an osteogenic environment with enhanced PTH anabolism. These data highlight a unique function for osteal macrophages in skeletal homeostasis.
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Zhang Y, Wang X, Yang H, Liu H, Lu Y, Han L, Liu G. Kinase AKT controls innate immune cell development and function. Immunology 2013; 140:143-52. [PMID: 23692658 DOI: 10.1111/imm.12123] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/13/2013] [Accepted: 05/16/2013] [Indexed: 12/17/2022] Open
Abstract
The critical roles of kinase AKT in tumour cell proliferation, apoptosis and protein synthesis have been widely recognized. But AKT also plays an important role in immune modulation. Recent studies have confirmed that kinase AKT can regulate the development and functions of innate immune cells (neutrophil, macrophage and dendritic cell). Studies have shown that different isoforms of kinase AKT have different effects in regulating immunity-related diseases, mainly through the mammalian target of rapamycin-dependent or -independent pathways. The purpose of this review is to illustrate the immune modulating effects of kinase AKT on innate immune cell development, survival and function.
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Affiliation(s)
- Yan Zhang
- Department of Immunology, Shanghai Medical College, Fudan University, Shanghai, China; Shenyang Agriculture University, Shenyang, China
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35
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Sanz AB, Sanchez-Niño MD, Izquierdo MC, Gonzalez-Espinoza L, Ucero AC, Poveda J, Ruiz-Andres O, Ruiz-Ortega M, Selgas R, Egido J, Ortiz A. Macrophages and recently identified forms of cell death. Int Rev Immunol 2013; 33:9-22. [PMID: 23802146 DOI: 10.3109/08830185.2013.771183] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Recent advances in cell death biology have uncovered an ever increasing range of cell death forms. Macrophages have a bidirectional relationship with cell death that modulates the immune response. Thus, macrophages engulf apoptotic cells and secrete cytokines that may promote cell death in parenchymal cells. Furthermore, the presence of apoptotic or necrotic dead cells in the microenvironment elicits differential macrophage responses. Apoptotic cells elicit anti-inflammatory responses in macrophages. By contrast macrophages may undergo a proinflammatory form of cell death (pyroptosis) in response to damage-associated molecular patterns (DAMPs) released from necrotic cells and also in response to pathogen-associated molecular patterns (PAMPs). Pyroptosis is a recently identified form of cell death that occurs predominantly in subsets of inflammatory macrophages and is associated to the release of interleukin-1β (IL-1β) and IL-18. Deregulation of these processes may result in disease. Thus, failure of macrophages to engulf apoptotic cells may be a source of autoantigens in autoimmune diseases, excessive macrophage release of proapoptotic factors or sterile pyroptosis may contribute to tissue injury and failure of pathogen-induced pyroptosis may contribute to pathogen survival. Ongoing research is exploring the therapeutic opportunities resulting this new knowledge.
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Affiliation(s)
- Ana B Sanz
- 1Laboratory of Nephrology, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid and Fundación Renal Iñigo Alvarez de Toledo, Madrid, Spain
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Bulloj A, Duan W, Finnemann SC. PI 3-kinase independent role for AKT in F-actin regulation during outer segment phagocytosis by RPE cells. Exp Eye Res 2013; 113:9-18. [PMID: 23669303 DOI: 10.1016/j.exer.2013.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/15/2013] [Accepted: 05/01/2013] [Indexed: 12/24/2022]
Abstract
Daily phagocytosis of photoreceptor outer segment fragments (POS) by the retinal pigment epithelium (RPE) is essential for vision. RPE cells use an uptake machinery that is highly similar to the one macrophages use to phagocytose apoptotic cells. In both forms of phagocytosis, particle binding induces phagocyte signaling that is required for F-actin assembly and re-arrangement beneath bound particles. Macrophage binding of apoptotic cells stimulates PI3 kinases (PI3K) and AKT kinases (AKT), which may be downstream of PI3K, and PI3K inhibition decreases engulfment. Here, we used specific inhibitory agents to investigate whether and how PI3K and AKT contribute to RPE phagocytosis. Either PI3K or AKT inhibition eliminated AKT activation by RPE cells in response to POS and increased the numbers of POS bound by RPE cells. Analyzing the quality of bound POS, we found a higher fraction of POS associated with F-actin phagocytic cups and myosin II in RPE receiving AKT inhibitor. In these cells, individual POS also recruited more F-actin and myosin II than POS in control cells. In contrast, PI3K inhibition did not alter frequency of phagocytic cups but individual cups contained less F-actin (but similar levels of myosin II) compared to control cups. Annexin AII, another phagocytic cup protein of RPE cells, associated with bound POS regardless of inhibitor treatment. POS engulfment proceeded normally if cells already carried surface-bound POS when receiving inhibitors. However, PI3K inhibition during POS binding blocked subsequent POS engulfment. In striking contrast, AKT inhibition had no effect on POS engulfment. Taken together, these results suggest distinct regulatory roles of PI3K and AKT during POS phagocytosis by RPE cells.
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Affiliation(s)
- Ayelen Bulloj
- Department of Biological Sciences, Center for Cancer, Genetic Diseases and Gene Regulation, Fordham University, Larkin Hall, 441 East Fordham Road, Bronx, NY 10458, USA
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Boulter L, Lu WY, Forbes SJ. Differentiation of progenitors in the liver: a matter of local choice. J Clin Invest 2013; 123:1867-73. [PMID: 23635784 PMCID: PMC3635730 DOI: 10.1172/jci66026] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The liver is a complex organ that requires multiple rounds of cell fate decision for development and homeostasis throughout the lifetime. During the earliest phases of organogenesis, the liver acquires a separate lineage from the pancreas and the intestine, and subsequently, the liver bud must appropriately differentiate to form metabolic hepatocytes and cholangiocytes for proper hepatic physiology. In addition, throughout life, the liver is bombarded with chemical and pathological insults, which require the activation and correct differentiation of adult progenitor cells. This Review seeks to provide an overview of the complex signaling relationships that allow these tightly regulated processes to occur.
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Affiliation(s)
- Luke Boulter
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom
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38
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Molecular and cellular mechanisms of macrophage survival in atherosclerosis. Basic Res Cardiol 2012; 107:297. [DOI: 10.1007/s00395-012-0297-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/20/2012] [Accepted: 08/26/2012] [Indexed: 01/22/2023]
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39
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Wang X, Lin WJ, Izumi K, Jiang Q, Lai KP, Xu D, Fang LY, Lu T, Li L, Xia S, Chang C. Increased infiltrated macrophages in benign prostatic hyperplasia (BPH): role of stromal androgen receptor in macrophage-induced prostate stromal cell proliferation. J Biol Chem 2012; 287:18376-85. [PMID: 22474290 DOI: 10.1074/jbc.m112.355164] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Infiltrated macrophages may play important roles in the development and progression of benign prostatic hyperplasia (BPH), but the underlying mechanisms remain largely unknown. We found increased macrophages infiltration in human and mouse BPH tissues. By establishing a co-culture transwell system, we found increased migration of macrophages and proliferation of prostate stromal cells during co-culture. Importantly, stromal androgen receptor (AR) could enhance the migration of macrophages and macrophage-mediated stromal cell proliferation. We identified CCL3 as an AR downstream player, and found CCL3 levels were notably increased in human and mouse BPH prostates. Ablation of prostate stromal AR in a mouse BPH model significantly reduced CCL3 expression levels in prostates. Consistently, targeting AR via an AR degradation enhancer, ASC-J9®, or neutralization of CCL3 with an antibody, resulted in suppression of macrophage migration and prostate stromal cell growth. Our study provides mechanistic insights on the regulation of prostate stromal cells by macrophages via stromal AR/CCL3 signaling pathways, which could potentially allow the development of therapeutic approaches for battling BPH with persistent inflammation.
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Affiliation(s)
- Xiaohai Wang
- Department of Pathology, University of Rochester Medical Center, Rochester, New York 14642, USA
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40
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Patel VA, Feng L, Lee DJ, Massenburg D, Pattabiraman G, Antoni A, Schwartz JH, Lieberthal W, Rauch J, Ucker DS, Levine JS. Recognition-dependent signaling events in response to apoptotic targets inhibit epithelial cell viability by multiple mechanisms: implications for non-immune tissue homeostasis. J Biol Chem 2012; 287:13761-77. [PMID: 22396534 DOI: 10.1074/jbc.m112.350843] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Apoptosis allows for the removal of damaged, aged, and/or excess cells without harm to surrounding tissue. To accomplish this, cells undergoing apoptosis acquire new activities that enable them to modulate the fate and function of nearby cells. We have shown that receptor-mediated recognition of apoptotic versus necrotic target cells by viable kidney proximal tubular epithelial cells (PTEC) modulates the activity of several signaling pathways critically involved in regulation of proliferation and survival. Generally, apoptotic and necrotic targets have opposite effects with apoptotic targets inhibiting and necrotic targets stimulating the activity of these pathways. Here we explore the consequences of these signaling differences. We show that recognition of apoptotic targets induces a profound decrease in PTEC viability through increased responder cell death and decreased proliferation. In contrast, necrotic targets promote viability through decreased death and increased proliferation. Both target types mediate their effects through a network of Akt-dependent and -independent events. Apoptotic targets modulate Akt-dependent viability in part through a reduction in cellular β-catenin and decreased inactivation of Bad. In contrast, Akt-independent modulation of viability occurs through activation of caspase-8, suggesting that death receptor-dependent pathways are involved. Apoptotic targets also activate p38, which partially protects responders from target-induced death. The response of epithelial cells varies depending on their tissue origin. Some cell lines, like PTEC, demonstrate decreased viability, whereas others (e.g. breast-derived) show increased viability. By acting as sentinels of environmental change, apoptotic targets allow neighboring cells, especially non-migratory epithelial cells, to monitor and potentially adapt to local stresses.
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Affiliation(s)
- Vimal A Patel
- Section of Nephrology, Department of Medicine, University of Illinois, Chicago, Illinois 60612, USA
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41
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Boulter L, Govaere O, Bird TG, Radulescu S, Ramachandran P, Pellicoro A, Ridgway RA, Seo SS, Spee B, Van Rooijen N, Sansom OJ, Iredale JP, Lowell S, Roskams T, Forbes SJ. Macrophage-derived Wnt opposes Notch signaling to specify hepatic progenitor cell fate in chronic liver disease. Nat Med 2012; 18:572-9. [PMID: 22388089 PMCID: PMC3364717 DOI: 10.1038/nm.2667] [Citation(s) in RCA: 569] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 01/09/2012] [Indexed: 12/14/2022]
Abstract
During chronic injury a population of bipotent hepatic progenitor cells (HPCs) become activated to regenerate both cholangiocytes and hepatocytes. Here we show in human diseased liver and mouse models of the ductular reaction that Notch and Wnt signaling direct specification of HPCs via their interactions with activated myofibroblasts or macrophages. In particular, we found that during biliary regeneration, expression of Jagged 1 (a Notch ligand) by myofibroblasts promoted Notch signaling in HPCs and thus their biliary specification to cholangiocytes. Alternatively, during hepatocyte regeneration, macrophage engulfment of hepatocyte debris induced Wnt3a expression. This resulted in canonical Wnt signaling in nearby HPCs, thus maintaining expression of Numb (a cell fate determinant) within these cells and the promotion of their specification to hepatocytes. By these two pathways adult parenchymal regeneration during chronic liver injury is promoted.
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Affiliation(s)
- Luke Boulter
- Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK
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42
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Herold S, Mayer K, Lohmeyer J. Acute lung injury: how macrophages orchestrate resolution of inflammation and tissue repair. Front Immunol 2011; 2:65. [PMID: 22566854 PMCID: PMC3342347 DOI: 10.3389/fimmu.2011.00065] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 11/08/2011] [Indexed: 12/24/2022] Open
Abstract
Lung macrophages are long living cells with broad differentiation potential, which reside in the lung interstitium and alveoli or are organ-recruited upon inflammatory stimuli. A role of resident and recruited macrophages in initiating and maintaining pulmonary inflammation in lung infection or injury has been convincingly demonstrated. More recent reports suggest that lung macrophages are main orchestrators of termination and resolution of inflammation. They are also initiators of parenchymal repair processes that are essential for return to homeostasis with normal gas exchange. In this review we will discuss cellular cross-talk mechanisms and molecular pathways of macrophage plasticity which define their role in inflammation resolution and in initiation of lung barrier repair following lung injury.
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Affiliation(s)
- Susanne Herold
- Department of Internal Medicine II, University of Giessen Lung Center Giessen, Germany.
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43
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Nagahara Y, Nagamori T, Tamegai H, Hitokuwada M, Yoshimi Y, Ikekita M, Shinomiya T. Inulin stimulates phagocytosis of PMA-treated THP-1 macrophages by involvement of PI3-kinases and MAP kinases. Biofactors 2011; 37:447-54. [PMID: 22038771 DOI: 10.1002/biof.186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 07/30/2011] [Indexed: 11/06/2022]
Abstract
Inulin is a polysaccharide that enhances various immune responses, mainly to T and B cells, natural killer cells, and macrophages in vivo and in vitro. Previous reports describe that inulin activates macrophages indirectly by affecting the alternative complement pathway. In this study, we examined the direct effect of inulin on PMA-treated THP-1 macrophages. Inulin treatment did not stimulate the proliferation of THP-1 macrophages at all. However, inulin treatment significantly increased phagocytosis of the polystyrene beads without the influence of serum. Doses of around 1 mg/mL had the maximal effect, and significant progression of phagocytosis occurred at times treated over 6 h. Inulin augmented phagocytosis not only with polystyrene beads but also with apoptotic cancer cells. The inulin-induced phagocytosis uptake was suppressed in Toll-like receptor (TLR) 4 mutated C3H/HeJ mice peritoneal macrophages. Moreover, inulin-induced THP-1 macrophage TNF-α secretion was inhibited using a blocking antibody specific to TLR4, suggesting that TLR4 is involved in the binding of inulin to macrophages. Furthermore, we used specific kinase inhibitors to assess the involvement of inulin-induced phagocytosis and revealed that phosphoinositide 3-kinase and mitogen-activated protein kinase, especially p38, participated in phagocytosis. These results suggest that inulin affects macrophages directly by involving the TLR4 signaling pathway and stimulating phagocytosis for enhancing immunomodulation.
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Affiliation(s)
- Yukitoshi Nagahara
- Department of Biotechnology, College of Science and Engineering, Tokyo Denki University, Hatoyama, Hiki-gun, Saitama, Japan.
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44
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Antoni A, Patel VA, Fan H, Lee DJ, Graham LH, Rosch CL, Spiegel DS, Rauch J, Levine JS. Macrophages from lupus-prone MRL mice have a conditional signaling abnormality that leads to dysregulated expression of numerous genes. Immunogenetics 2011; 63:291-308. [PMID: 21229240 PMCID: PMC3439499 DOI: 10.1007/s00251-010-0507-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 12/17/2010] [Indexed: 01/06/2023]
Abstract
Macrophages (mϕ) from pre-diseased mice of the major murine inbred models of spontaneous autoimmunity (AI), including multiple lupus-prone strains and the type I diabetes-prone NOD (non-obese diabetic) strain, have identical apoptotic target-dependent abnormalities. This characteristic feature of mϕ from AI-prone mice suggests that abnormal signaling events induced within mϕ following their interaction with apoptotic targets may predispose to AI. Such signaling abnormalities would affect predominantly the processing and presentation of self-antigen (i.e., derived from apoptotic targets), while sparing the processing and presentation of foreign antigen (i.e., derived from non-apoptotic sources). Here, we used DNA microarrays to test the hypothesis that mϕ from AI-prone mice (MRL/MpJ [MRL/+] or MRL/MpJ-Tnfrsf6 ( lpr ) [MRL/lpr]) differentially express multiple genes in comparison to non-AI mϕ (BALB/c), but do so in a largely apoptotic cell-dependent manner. Mϕ were stimulated with lipopolysaccharide, a potent innate stimulus, in the presence or absence of serum (an experimental surrogate for apoptotic targets). In accord with our hypothesis, the number of genes differentially expressed by MRL mϕ was significantly increased in the presence vs. the absence of serum, the apoptotic target surrogate (n = 401 vs. n = 201). Notably, for genes differentially expressed by MRL mϕ in the presence of serum, serum-free culture normalized their expression to a level statistically indistinguishable from that by non-AI mϕ. Comparisons of mϕ from AI-prone NOD and non-AI C57BL/6 mice corroborated these findings. Together, these data support the hypothesis that mϕ from MRL and other AI-prone mice are characterized by a conditional abnormality elicited by serum lipids or apoptotic targets.
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Affiliation(s)
- Angelika Antoni
- Department of Biology, Kutztown University of Pennsylvania, Kutztown, PA 19530, USA
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45
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Pascual-García M, Carbó JM, León T, Matalonga J, Out R, Van Berkel T, Sarrias MR, Lozano F, Celada A, Valledor AF. Liver X receptors inhibit macrophage proliferation through downregulation of cyclins D1 and B1 and cyclin-dependent kinases 2 and 4. THE JOURNAL OF IMMUNOLOGY 2011; 186:4656-67. [PMID: 21398609 DOI: 10.4049/jimmunol.1000585] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Macrophages serve essential functions as regulators of immunity and homeostasis, and their proliferation contributes to pathogenesis of certain disorders. In this report, we show that induction of macrophage proliferation by the growth factor M-CSF is negatively modulated by agonists that activate the nuclear receptor liver X receptor (LXR), both in vitro and in vivo. Both isoforms LXR α and β are involved in the antiproliferative actions of LXR ligands in macrophages. In contrast, M-CSF does not exert negative effects on LXR-mediated gene expression. Treatment with LXR agonists results in the accumulation of macrophages in the G(0)/G(1) phase of the cell cycle without affecting ERK-1/2 phosphorylation. The use of small interfering RNA or genetically modified mice revealed that, in contrast to other cellular models, functional expression of either the cyclin-dependent kinase inhibitor p27KIP1 or the cholesterol transporters ATP-binding cassette A1 or ATP-binding cassette G1 was not required for the antiproliferative effects of LXR agonists in macrophages. Western blot analysis revealed that protein expression of key molecules that regulate progression through the cell cycle, such as cyclins D1 and B1 and cyclin-dependent kinases 2 and 4, was downregulated upon LXR activation. These observations suggest a role for LXR agonists in limiting macrophage proliferative responses associated to pathogenic disorders.
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Affiliation(s)
- Mónica Pascual-García
- Nuclear Receptor Group, Department of Physiology, School of Biology, University of Barcelona, 08028 Barcelona, Spain
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46
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Gregory CD, Pound JD. Cell death in the neighbourhood: direct microenvironmental effects of apoptosis in normal and neoplastic tissues. J Pathol 2010; 223:177-94. [PMID: 21125674 DOI: 10.1002/path.2792] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 09/12/2010] [Accepted: 09/21/2010] [Indexed: 12/24/2022]
Abstract
Here we consider the impact of the physiological cell-death programme on normal tissue homeostasis and on disease pathogenesis, with particular reference to evolution and progression of neoplasia. We seek to describe the direct contributions played by apoptosis in creating the microenvironments of normal and malignant tissues and to discuss the molecular mechanisms underlying the elements of the '3Rs' that define the meaning of apoptosis: recognition, response, and removal. Apoptotic cells elicit responses in other cell types-both phagocytic and non-phagocytic-through short- and long-range signalling modes that range from direct contact to intercellular communication via membrane-bound microparticles. Such cellular responses include migration, proliferation, and differentiation, as well as production of immunomodulatory and anti-inflammatory mediators together with, in the case of phagocytes, engulfment, and breakdown of apoptotic cells. In normal tissues, the removal of apoptotic cells is rapid and typically non-phlogistic. We discuss the importance of this clearance process in tissue homeostasis and the consequences of its failure in disease pathogenesis. Using the typical cell culture environment in vitro as an illustrative example in which apoptosis occurs commonly in the absence of the removal mechanisms, we also discuss the inhibitory effects of persistent apoptotic cells on their otherwise viable neighbours. Since apoptosis is a common and sustained event in high-grade malignancies, we hypothesize on its purposeful role in conditioning the tumour microenvironment. We propose that apoptosis subserves several pro-tumour functions-trophic, anti-inflammatory, and immunomodulatory-and we identify strategies targeting host responses to apoptotic cells as promising modes of future therapies that could be applied to multiple cancer types in which tumour-cell apoptosis is active.
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Affiliation(s)
- Christopher D Gregory
- MRC Centre for Inflammation Research, University of Edinburgh, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
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Patel VA, Lee DJ, Longacre-Antoni A, Feng L, Lieberthal W, Rauch J, Ucker DS, Levine JS. Apoptotic and necrotic cells as sentinels of local tissue stress and inflammation: response pathways initiated in nearby viable cells. Autoimmunity 2009; 42:317-21. [PMID: 19811288 DOI: 10.1080/08916930902832124] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Virtually all cells in the body have the capacity to recognize and respond to dead cells. Viable cells discriminate apo from nec targets via distinct cell surface receptors. Engagement of these receptors induces "recognition-dependent" signaling events in viable responding cells that differ for apo vs. nec targets. Although "engulfment-dependent" signaling events also contribute to the response by viable cells, these events do not differ for apo vs. nec targets. While many signaling events are conserved across diverse cell lineages, other signaling events, especially those involving Akt, demonstrate lineage-specific variation. Whereas apo targets activate Akt in MPhi, they inhibit Akt in kidney epithelial cells. Differences in the responses to dead targets by viable migratory cells, such as MPhi, and viable fixed cells, such as kidney epithelial cells, permit cell-specific adaptations to local environmental change or stress. We propose that dead cells (apo and nec) act as sentinels to alert nearby viable cells to local environmental change or stress.
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Affiliation(s)
- Vimal A Patel
- Section of Nephrology, Department of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
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48
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Patel VA, Lee DJ, Feng L, Antoni A, Lieberthal W, Schwartz JH, Rauch J, Ucker DS, Levine JS. Recognition of apoptotic cells by epithelial cells: conserved versus tissue-specific signaling responses. J Biol Chem 2009; 285:1829-40. [PMID: 19910463 DOI: 10.1074/jbc.m109.018440] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During apoptosis, cells acquire new activities that enable them to modulate the fate and function of interacting phagocytes, particularly macrophages (m). Although the best known of these activities is anti-inflammatory, apoptotic targets also influence m survival and proliferation by modulating proximal signaling events, such as MAPK modules and Akt. We asked whether modulation of these same signaling events extends to epithelial cells, a minimally phagocytic cell type. We used BU.MPT cells, a mouse kidney epithelial cell line, as our primary model, but we also evaluated several epithelial cell lines of distinct tissue origins. Like m, mouse kidney epithelial cells recognized apoptotic and necrotic targets through distinct non-competing receptors, albeit with lower binding capacity and markedly reduced phagocytosis. Also, modulation of inflammatory activity and MAPK-dependent signaling by apoptotic and necrotic targets was indistinguishable in kidney epithelial cells and m. In contrast, modulation of Akt-dependent signaling differed dramatically between kidney epithelial cells and m. In kidney epithelial cells, modulation of Akt was linked to target cell recognition, independently of phagocytosis, whereas in m, modulation was linked to phagocytosis. Moreover, recognition of apoptotic and necrotic targets by kidney epithelial cells elicited opposite responses; apoptotic targets inhibited whereas necrotic targets stimulated Akt activity. These data confirm that nonprofessional phagocytes recognize and respond to dying cells, albeit in a manner partially distinct from m. By acting as sentinels of environmental change, apoptotic and necrotic targets may permit neighboring viable cells, especially non-migratory epithelial cells, to monitor and adapt to local stresses.
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Affiliation(s)
- Vimal A Patel
- Section of Nephrology, Department of Medicine, University of Illinois, Chicago, Illinois 60612, USA
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49
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Jiang JX, Mikami K, Venugopal S, Li Y, Török NJ. Apoptotic body engulfment by hepatic stellate cells promotes their survival by the JAK/STAT and Akt/NF-kappaB-dependent pathways. J Hepatol 2009; 51:139-48. [PMID: 19457567 PMCID: PMC2765371 DOI: 10.1016/j.jhep.2009.03.024] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 02/20/2009] [Accepted: 03/02/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND/AIMS We have previously shown that phagocytosis of apoptotic bodies (AB) by hepatic stellate cells (HSC) is profibrogenic. As HSC survival is central to the progression of liver fibrosis, our goal was to investigate if phagocytosis induces HSC survival. METHODS Apoptosis of phagocytosing HSC was studied in the presence of known apoptotic agents. The JAK/STAT- and PI3K/Akt-dependent pathways, NF-kappaB activation and expression of the anti-apoptotic proteins Mcl-1 and A1 were evaluated. Apoptosis was assessed after blocking A1 by an siRNA approach. RESULTS Phagocytosing HSC were resistant to FasL/cycloheximide or TRAIL-induced apoptosis. Inhibition of the JAK/STAT or PI3K-mediated pathways induced apoptosis of HSC. Phagocytosis induced JAK1/STAT3 phosphorylation, and this was prevented by inhibiting JAK. Translocation of STAT3 to the nucleus was also blocked by JAK inhibition. Mcl-1 expression was upregulated in a JAK-dependent manner. PI3K-dependent phosphorylation of Akt depended on NADPH oxidase activity and superoxide production. NF-kappaB activation and subsequent upregulation of A1 was observed, and A1 inhibition induced apoptosis of HSC. CONCLUSION Phagocytosis of AB promotes HSC survival by two pathways, of which the A1 dependent is more significant. This represents a new mechanism by which engulfment of AB contributes to the propagation of liver fibrosis.
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Affiliation(s)
- Joy X. Jiang
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, UC Davis Medical Center, Sacramento, CA, USA
| | - Kenichiro Mikami
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, UC Davis Medical Center, Sacramento, CA, USA
| | - Senthil Venugopal
- Department of Internal Medicine, Division of Transplant Medicine, UC Davis Medical Center, Sacramento, CA, USA
| | - Yong Li
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, UC Davis Medical Center, Sacramento, CA, USA
| | - Natalie J Török
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, UC Davis Medical Center, Sacramento, CA, USA
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Kirsch T, Woywodt A, Klose J, Wyss K, Beese M, Erdbruegger U, Grossheim M, Haller H, Haubitz M. Endothelial-derived thrombospondin-1 promotes macrophage recruitment and apoptotic cell clearance. J Cell Mol Med 2009; 14:1922-34. [PMID: 19508384 PMCID: PMC3823274 DOI: 10.1111/j.1582-4934.2009.00799.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Rapid apoptotic cell engulfment is crucial for prevention of inflammation and autoimmune diseases and is conducted by special immunocompetent cells like macrophages or immature dendritic cells. We recently demonstrated that endothelial cells (ECs) also participate in apoptotic cell clearance. However, in contrast to conventional phagocytes they respond with an inflammatory phenotype. To further confirm these pro-inflammatory responses human ECs were exposed to apoptotic murine ECs and changes in thrombospondin-1 (TSP-1) expression and in activation of intracellular signalling cascades were determined by real-time qPCR, immunoblotting and immunocytochemistry. Human primary macrophages or monocytic lymphoma cells (U937) were incubated with conditioned supernatant of human ECs exposed to apoptotic cells and changes in activation, migration and phagocytosis were monitored. Finally, plasma levels of TSP-1 in patients with anti-neutrophil cytoplasmic antibody(ANCA)-associated vasculitis (AAV) were determined by ELISA. We provided evidence that apoptotic cells induce enhanced expression of TSP-1 in human ECs and that this increase in TSP-1 is mediated by the mitogen-activated protein kinases (MAPK) ERK1 and 2 and their upstream regulators MEK and B-Raf. We also showed that plasma TSP-1 levels are increased in patients with AAV. Finally, we showed that conditioned supernatant of ECs exposed to apoptotic cells induces pro-inflammatory responses in monocytes or U937 cells and demonstrated that increased TSP-1 expression enhances migration and facilitates engulfment of apoptotic cells by monocyte-derived macrophages or U937 cells. These findings suggest that under pathological conditions with high numbers of uncleared dying cells in the circulation endothelial-derived elevated TSP-1 level may serve as an attraction signal for phagocytes promoting enhanced recognition and clearance of apoptotic cells.
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Affiliation(s)
- Torsten Kirsch
- Division of Nephrology, Department of Internal Medicine, Hannover Medical School, Germany.
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