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Branco ACC, Rogers LM, Aronoff DM. Folate Receptor Beta Signaling in the Regulation of Macrophage Antimicrobial Immune Response: A Scoping Review. Biomed Hub 2024; 9:31-37. [PMID: 38406385 PMCID: PMC10890800 DOI: 10.1159/000536186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 01/05/2024] [Indexed: 02/27/2024] Open
Abstract
Introduction Folate, vitamin B9, is a water-soluble vitamin that is essential to cellular proliferation and division. In addition to the reduced folate carrier, eukaryotic cells take up folate through endocytosis mediated by one of two GPI-anchored folate receptors (FRs), FRα or FRβ. Two other isoforms of FR exist, FRγ and FRδ, neither of which support endocytic activities of FR signaling. FRβ is expressed primarily by monocytes and macrophages and highly expressed on activated macrophages. Macrophage expression of FRβ suggests a role for this receptor in modulating function of these immune sentinels, particularly as they engage in inflammatory processes. Despite several studies suggesting that folates can suppress inflammatory responses of macrophages to proinflammatory stimuli, there appears to be a lack of basic research examining the role of FRβ in modulating macrophage responses to microbial sensing. We therefore conducted a scoping review to assess evidence within the published literature addressing the question, "what is known about the extent to which FRβ regulates macrophage responses to sensing, and responding to, microorganisms?". Methods As a strategy for the study selection, we queried articles indexed in the research database PubMed and the search engine Google Scholar (up until August 12, 2023), including combinations of the research words: macrophage, folate receptor beta, FOLR2. Results We identified 2 relevant articles out of 153 that are worth discussing here, none of which directly addressed our research question. Conclusion There is an unmet need to better define the contribution of FRβ to regulating the macrophage response to microbes.
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Affiliation(s)
- Anna C.C. Castelo Branco
- Division of Infectious Diseases, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Laboratory of Dermatology and Immunodeficiencies (LIM56), Institute of Tropical Medicine, University of São Paulo, São Paulo, Brazil
| | - Lisa M. Rogers
- Division of Infectious Diseases, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - David M. Aronoff
- Division of Infectious Diseases, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
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2
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van der Geest KSM, Sandovici M, Nienhuis PH, Slart RHJA, Heeringa P, Brouwer E, Jiemy WF. Novel PET Imaging of Inflammatory Targets and Cells for the Diagnosis and Monitoring of Giant Cell Arteritis and Polymyalgia Rheumatica. Front Med (Lausanne) 2022; 9:902155. [PMID: 35733858 PMCID: PMC9207253 DOI: 10.3389/fmed.2022.902155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/13/2022] [Indexed: 12/26/2022] Open
Abstract
Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are two interrelated inflammatory diseases affecting patients above 50 years of age. Patients with GCA suffer from granulomatous inflammation of medium- to large-sized arteries. This inflammation can lead to severe ischemic complications (e.g., irreversible vision loss and stroke) and aneurysm-related complications (such as aortic dissection). On the other hand, patients suffering from PMR present with proximal stiffness and pain due to inflammation of the shoulder and pelvic girdles. PMR is observed in 40-60% of patients with GCA, while up to 21% of patients suffering from PMR are also affected by GCA. Due to the risk of ischemic complications, GCA has to be promptly treated upon clinical suspicion. The treatment of both GCA and PMR still heavily relies on glucocorticoids (GCs), although novel targeted therapies are emerging. Imaging has a central position in the diagnosis of GCA and PMR. While [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) has proven to be a valuable tool for diagnosis of GCA and PMR, it possesses major drawbacks such as unspecific uptake in cells with high glucose metabolism, high background activity in several non-target organs and a decrease of diagnostic accuracy already after a short course of GC treatment. In recent years, our understanding of the immunopathogenesis of GCA and, to some extent, PMR has advanced. In this review, we summarize the current knowledge on the cellular heterogeneity in the immunopathology of GCA/PMR and discuss how recent advances in specific tissue infiltrating leukocyte and stromal cell profiles may be exploited as a source of novel targets for imaging. Finally, we discuss prospective novel PET radiotracers that may be useful for the diagnosis and treatment monitoring in GCA and PMR.
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Affiliation(s)
- Kornelis S. M. van der Geest
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Maria Sandovici
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Pieter H. Nienhuis
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Riemer H. J. A. Slart
- Department of Nuclear Medicine and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
- Department of Biomedical Photonic Imaging Group, University of Twente, Enschede, Netherlands
| | - Peter Heeringa
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Elisabeth Brouwer
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - William F. Jiemy
- Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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3
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Herr SA, Gardeen SS, Low PS, Shi R. Targeted delivery of acrolein scavenger hydralazine in spinal cord injury using folate-linker-drug conjugation. Free Radic Biol Med 2022; 184:66-73. [PMID: 35398493 DOI: 10.1016/j.freeradbiomed.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/30/2022] [Accepted: 04/03/2022] [Indexed: 11/26/2022]
Abstract
Oxidative stress has been shown to play a critical pathogenic role in functional loss after spinal cord injury (SCI). As a direct result of oxidative stress, lipid peroxidation-derived aldehydes have emerged as key culprits that sustain secondary injury and contribute significantly to pathological outcomes. Acrolein, a neurotoxin, has been shown to be elevated in SCI and can result in post-SCI neurological deficits. Reducing acrolein has therefore emerged as a novel and effective therapeutic strategy in SCI. Previous studies have revealed that hydralazine, an FDA approved blood pressure lowering medication, when administered after SCI shows strong acrolein scavenging capabilities and significantly improves cellular and behavioral outcomes. However, while effective at scavenging acrolein, hydralazine's blood pressure lowering activity can have a detrimental impact on neurotrauma patients. Here, our goal was to preserve the acrolein scavenging capability while mitigating the effect of hydralazine on blood pressure. We accomplished this using a folate-targeted delivery system to deploy hydralazine to the folate receptor positive inflammatory site of the cord injury. Using a model of rat SCI, we found that this system is effective for targeting the injury site, and that folate targeted hydralazine can scavenge acrolein without significantly impacting blood pressure.
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Affiliation(s)
- Seth A Herr
- Center for Paralysis Research & Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University. Lynn Hall, 625 N Harrison St. West Lafayette, IN, 47907, USA.
| | - Spencer S Gardeen
- Department of Chemistry, College of Science, Purdue University. Drug Discovery Building, 720 Clinic Dr. West Lafayette, IN, 47907, USA.
| | - Philip S Low
- Department of Chemistry, College of Science, Purdue University. Drug Discovery Building, 720 Clinic Dr. West Lafayette, IN, 47907, USA.
| | - Riyi Shi
- Center for Paralysis Research & Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University. Lynn Hall, 625 N Harrison St. West Lafayette, IN, 47907, USA.
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4
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Li X, Wang R, Zhang Y, Han S, Gan Y, Liang Q, Ma X, Rong P, Wang W, Li W. Molecular imaging of tumor-associated macrophages in cancer immunotherapy. Ther Adv Med Oncol 2022; 14:17588359221076194. [PMID: 35251314 PMCID: PMC8891912 DOI: 10.1177/17588359221076194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 01/10/2022] [Indexed: 12/20/2022] Open
Abstract
Tumor-associated macrophages (TAMs), the most abundant inflammatory cell group in the tumor microenvironment, play an essential role in tumor immune regulation. The infiltration degree of TAMs in the tumor microenvironment is closely related to tumor growth and metastasis, and TAMs have become a promising target in tumor immunotherapy. Molecular imaging is a new interdisciplinary subject that combines medical imaging technology with molecular biology, nuclear medicine, radiation medicine, and computer science. The latest progress in molecular imaging allows the biological processes of cells to be visualized in vivo, which makes it possible to better understand the density and distribution of macrophages in the tumor microenvironment. This review mainly discusses the application of targeting TAM in tumor immunotherapy and the imaging characteristics and progress of targeting TAM molecular probes using various imaging techniques.
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Affiliation(s)
- Xiaoying Li
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Ruike Wang
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Yangnan Zhang
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Shuangze Han
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Yu Gan
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Qi Liang
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Xiaoqian Ma
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Pengfei Rong
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Wei Wang
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
| | - Wei Li
- Department of Radiology, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan, People’s Republic of China
- Cell Transplantation and Gene Therapy Institute, The Third Xiangya Hospital, Central South University, Changsha, People’s Republic of China
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Palani S, Miner MWG, Virta J, Liljenbäck H, Eskola O, Örd T, Ravindran A, Kaikkonen MU, Knuuti J, Li XG, Saraste A, Roivainen A. Exploiting Glutamine Consumption in Atherosclerotic Lesions by Positron Emission Tomography Tracer (2S,4R)-4-18F-Fluoroglutamine. Front Immunol 2022; 13:821423. [PMID: 35145523 PMCID: PMC8822173 DOI: 10.3389/fimmu.2022.821423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 01/03/2022] [Indexed: 11/23/2022] Open
Abstract
Increased glutamine metabolism by macrophages is associated with development of atherosclerotic lesions. Positron emission tomography/computed tomography (PET/CT) with a glutamine analog (2S,4R)-4-18F-fluoroglutamine (18F-FGln) allows quantification of glutamine consumption in vivo. Here, we investigated uptake of 18F-FGln by atherosclerotic lesions in mice and compared the results with those obtained using the glucose analog 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG). Uptake of 18F-FGln and 18F-FDG by healthy control mice (C57BL/6JRj) and atherosclerotic low-density lipoprotein receptor-deficient mice expressing only apolipoprotein B100 (LDLR−/−ApoB100/100) was investigated. The mice were injected intravenously with 18F-FGln or 18F-FDG for in vivo PET/CT imaging. After sacrifice at 70 minutes post-injection, tracer uptake was analyzed by gamma counting of excised tissues and by autoradiography of aorta cryosections, together with histological and immunohistochemical analyses. We found that myocardial uptake of 18F-FGln was low. PET/CT detected lesions in the aortic arch, with a target-to-background ratio (SUVmax, aortic arch/SUVmean, blood) of 1.95 ± 0.42 (mean ± standard deviation). Gamma counting revealed that aortic uptake of 18F-FGln by LDLR−/−ApoB100/100 mice (standardized uptake value [SUV], 0.35 ± 0.06) was significantly higher than that by healthy controls (0.20 ± 0.08, P = 0.03). More detailed analysis by autoradiography revealed that the plaque-to-healthy vessel wall ratio of 18F-FGln (2.90 ± 0.42) was significantly higher than that of 18F-FDG (1.93 ± 0.22, P = 0.004). Immunohistochemical staining confirmed that 18F-FGln uptake in plaques co-localized with glutamine transporter SLC7A7-positive macrophages. Collectively these data show that the 18F-FGln PET tracer detects inflamed atherosclerotic lesions. Thus, exploiting glutamine consumption using 18F-FGln PET may have translational relevance for studying atherosclerotic inflammation.
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Affiliation(s)
- Senthil Palani
- Turku PET Centre, University of Turku, Turku, Finland
- *Correspondence: Anne Roivainen, ; Senthil Palani,
| | | | - Jenni Virta
- Turku PET Centre, University of Turku, Turku, Finland
| | - Heidi Liljenbäck
- Turku PET Centre, University of Turku, Turku, Finland
- Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - Olli Eskola
- Turku PET Centre, University of Turku, Turku, Finland
| | - Tiit Örd
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Aarthi Ravindran
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Minna U. Kaikkonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Juhani Knuuti
- Turku PET Centre, University of Turku, Turku, Finland
- Turku PET Centre, Turku University Hospital, Turku, Finland
- InFLAMES Research Flagship Center, University of Turku, Turku, Finland
| | - Xiang-Guo Li
- Turku PET Centre, University of Turku, Turku, Finland
- InFLAMES Research Flagship Center, University of Turku, Turku, Finland
| | - Antti Saraste
- Turku PET Centre, University of Turku, Turku, Finland
- Heart Center, Turku University Hospital and University of Turku, Turku, Finland
| | - Anne Roivainen
- Turku PET Centre, University of Turku, Turku, Finland
- Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku PET Centre, Turku University Hospital, Turku, Finland
- InFLAMES Research Flagship Center, University of Turku, Turku, Finland
- *Correspondence: Anne Roivainen, ; Senthil Palani,
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Li XG, Velikyan I, Viitanen R, Roivainen A. PET radiopharmaceuticals for imaging inflammatory diseases. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00075-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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7
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Functionally Heterogenous Macrophage Subsets in the Pathogenesis of Giant Cell Arteritis: Novel Targets for Disease Monitoring and Treatment. J Clin Med 2021; 10:jcm10214958. [PMID: 34768479 PMCID: PMC8585092 DOI: 10.3390/jcm10214958] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/20/2021] [Accepted: 10/23/2021] [Indexed: 12/19/2022] Open
Abstract
Giant cell arteritis (GCA) is a granulomatous large-vessel vasculitis that affects adults above 50 years of age. In GCA, circulating monocytes are recruited to the inflamed arteries. With cues from the vascular microenvironment, they differentiate into macrophages and play important roles in the pathogenesis of GCA via pro-inflammatory cytokine production and vascular remodeling. However, a deeper understanding of macrophage heterogeneity in GCA pathogenesis is needed to assist the development of novel diagnostic tools and targeted therapies. Here, we review the current knowledge on macrophage heterogeneity and diverse functions of macrophage subsets in the pathogenesis of GCA. We next discuss the possibility to exploit their heterogeneity as a source of novel biomarkers and as targets for nuclear imaging. Finally, we discuss novel macrophage-targeted therapies and future directions for targeting these cells in GCA.
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Preparation and Evaluation of Novel Folate Isonitrile 99mTc Complexes as Potential Tumor Imaging Agents to Target Folate Receptors. Molecules 2021; 26:molecules26154552. [PMID: 34361705 PMCID: PMC8348780 DOI: 10.3390/molecules26154552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/17/2021] [Accepted: 07/26/2021] [Indexed: 11/17/2022] Open
Abstract
In order to seek novel technetium-99m folate receptor-targeting agents, two folate derivatives (CN5FA and CNPFA) were synthesized and radiolabeled to obtain [99mTc]Tc-CN5FA and [99mTc]Tc-CNPFA complexes, which exhibited high radiochemical purity (>95%) without purification, hydrophilicity, and good stability in vitro. The KB cell competitive binding experiments indicated that [99mTc]Tc-CN5FA and [99mTc]Tc-CNPFA had specificity to folate receptor. Biodistribution studies in KB tumor-bearing mice illustrated that [99mTc]Tc-CN5FA and [99mTc]Tc-CNPFA had specific tumor uptake. Compared with [99mTc]Tc-CN5FA, the tumor/muscle ratios of [99mTc]Tc-CNPFA were higher, resulting in a better SPECT/CT imaging background. According to the results, the two 99mTc complexes have potential as tumor imaging agents to target folate receptors.
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Imaging Inflammation with Positron Emission Tomography. Biomedicines 2021; 9:biomedicines9020212. [PMID: 33669804 PMCID: PMC7922638 DOI: 10.3390/biomedicines9020212] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 01/28/2021] [Accepted: 02/12/2021] [Indexed: 12/19/2022] Open
Abstract
The impact of inflammation on the outcome of many medical conditions such as cardiovascular diseases, neurological disorders, infections, cancer, and autoimmune diseases has been widely acknowledged. However, in contrast to neurological, oncologic, and cardiovascular disorders, imaging plays a minor role in research and management of inflammation. Imaging can provide insights into individual and temporospatial biology and grade of inflammation which can be of diagnostic, therapeutic, and prognostic value. There is therefore an urgent need to evaluate and understand current approaches and potential applications for imaging of inflammation. This review discusses radiotracers for positron emission tomography (PET) that have been used to image inflammation in cardiovascular diseases and other inflammatory conditions with a special emphasis on radiotracers that have already been successfully applied in clinical settings.
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