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Slominski RM, Chen JY, Raman C, Slominski AT. Photo-neuro-immuno-endocrinology: How the ultraviolet radiation regulates the body, brain, and immune system. Proc Natl Acad Sci U S A 2024; 121:e2308374121. [PMID: 38489380 PMCID: PMC10998607 DOI: 10.1073/pnas.2308374121] [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] [Indexed: 03/17/2024] Open
Abstract
Ultraviolet radiation (UVR) is primarily recognized for its detrimental effects such as cancerogenesis, skin aging, eye damage, and autoimmune disorders. With exception of ultraviolet B (UVB) requirement in the production of vitamin D3, the positive role of UVR in modulation of homeostasis is underappreciated. Skin exposure to UVR triggers local responses secondary to the induction of chemical, hormonal, immune, and neural signals that are defined by the chromophores and extent of UVR penetration into skin compartments. These responses are not random and are coordinated by the cutaneous neuro-immuno-endocrine system, which counteracts the action of external stressors and accommodates local homeostasis to the changing environment. The UVR induces electrical, chemical, and biological signals to be sent to the brain, endocrine and immune systems, as well as other central organs, which in concert regulate body homeostasis. To achieve its central homeostatic goal, the UVR-induced signals are precisely computed locally with transmission through nerves or humoral signals release into the circulation to activate and/or modulate coordinating central centers or organs. Such modulatory effects will be dependent on UVA and UVB wavelengths. This leads to immunosuppression, the activation of brain and endocrine coordinating centers, and the modification of different organ functions. Therefore, it is imperative to understand the underlying mechanisms of UVR electromagnetic energy penetration deep into the body, with its impact on the brain and internal organs. Photo-neuro-immuno-endocrinology can offer novel therapeutic approaches in addiction and mood disorders; autoimmune, neurodegenerative, and chronic pain-generating disorders; or pathologies involving endocrine, cardiovascular, gastrointestinal, or reproductive systems.
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Affiliation(s)
- Radomir M. Slominski
- Departments of Genetics, the University of Alabama at Birmingham, Birmingham, AL35294
| | - Jake Y. Chen
- Department of Biomedical Informatics and Data Science, the University of Alabama at Birmingham, Birmingham, AL35294
- Comprehensive Cancer Center, Cancer Chemoprevention Program, University of Alabama at Birmingham, Birmingham, AL35294
| | - Chander Raman
- Department of Dermatology, the University of Alabama at Birmingham, Birmingham, AL35294
| | - Andrzej T. Slominski
- Comprehensive Cancer Center, Cancer Chemoprevention Program, University of Alabama at Birmingham, Birmingham, AL35294
- Department of Dermatology, the University of Alabama at Birmingham, Birmingham, AL35294
- Veteran Administration Medical Center, Birmingham, AL35294
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2
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Frommeyer TC, Gilbert MM, Brittain GV, Wu T, Nguyen TQ, Rohan CA, Travers JB. UVB-Induced Microvesicle Particle Release and Its Effects on the Cutaneous Microenvironment. Front Immunol 2022; 13:880850. [PMID: 35603177 PMCID: PMC9120817 DOI: 10.3389/fimmu.2022.880850] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/04/2022] [Indexed: 12/14/2022] Open
Abstract
Ultraviolet B radiation (UVB) has profound effects on human skin that results in a broad spectrum of immunological local and systemic responses and is the major cause of skin carcinogenesis. One important area of study in photobiology is how UVB is translated into effector signals. As the skin is exposed to UVB light, subcellular microvesicle particles (MVP), a subtype of bioactive extracellular vesicles, are released causing a variety of local and systemic immunological effects. In this review, we highlight keratinocyte MVP release in keratinocytes in response to UVB. Specifically, Platelet-activating factor receptor agonists generated by UVB result in MVP released from keratinocytes. The downstream effects of MVP release include the ability of these subcellular particles to transport agents including the glycerophosphocholine-derived lipid mediator Platelet-activating factor (PAF). Moreover, even though UVB is only absorbed in the epidermis, it appears that PAF release from MVPs also mediates systemic immunosuppression and enhances tumor growth and metastasis. Tumor cells expressing PAF receptors can use this mechanism to evade chemotherapy responses, leading to treatment resistance for advanced cancers such as melanoma. Furthermore, novel pharmacological agents provide greater insight into the UVB-induced immune response pathway and a potential target for pharmacological intervention. This review outlines the need to more clearly elucidate the mechanism linking UVB-irradiation with the cutaneous immune response and its pathological manifestations. An improved understanding of this process can result in new insights and treatment strategies for UVB-related disorders from carcinogenesis to photosensitivity.
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Affiliation(s)
- Timothy C. Frommeyer
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
| | - Michael M. Gilbert
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
| | - Garrett V. Brittain
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
| | - Tongfan Wu
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
| | - Trang Q. Nguyen
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
| | - Craig A. Rohan
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
- Department of Dermatology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
- Department of Medicine, Dayton Veterans Administration Medical Center, Dayton, OH, United States
| | - Jeffrey B. Travers
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
- Department of Dermatology, Boonshoft School of Medicine at Wright State University, Dayton, OH, United States
- Department of Medicine, Dayton Veterans Administration Medical Center, Dayton, OH, United States
- *Correspondence: Jeffrey B. Travers,
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3
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Vieyra-Garcia PA, Wolf P. A deep dive into UV-based phototherapy: Mechanisms of action and emerging molecular targets in inflammation and cancer. Pharmacol Ther 2020; 222:107784. [PMID: 33316286 DOI: 10.1016/j.pharmthera.2020.107784] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023]
Abstract
UV-based phototherapy (including psoralen plus UVA (PUVA), UVB and UVA1) has a long, successful history in the management of numerous cutaneous disorders. Photoresponsive diseases are etiologically diverse, but most involve disturbances in local (and occasionally systemic) inflammatory cells and/or abnormalities in keratinocytes that trigger inflammation. UV-based phototherapy works by regulating the inflammatory component and inducing apoptosis of pathogenic cells. This results in a fascinating and complex network of simultaneous events-immediate transcriptional changes in keratinocytes, immune cells, and pigment cells; the emergence of apoptotic bodies; and the trafficking of antigen-presenting cells in skin-that quickly transform the microenvironment of UV-exposed skin. Molecular elements in this system of UV recognition and response include chromophores, metabolic byproducts, innate immune receptors, neurotransmitters and mediators such as chemokines and cytokines, antimicrobial peptides, and platelet activating factor (PAF) and PAF-like molecules that simultaneously shape the immunomodulatory effects of UV and their interplay with the microbiota of the skin and beyond. Phototherapy's key effects-proapoptotic, immunomodulatory, antipruritic, antifibrotic, propigmentary, and pro-prebiotic-promote clinical improvement in various skin diseases such as psoriasis, atopic dermatitis (AD), graft-versus-host disease (GvHD), vitiligo, scleroderma, and cutaneous T-cell lymphoma (CTCL) as well as prevention of polymorphic light eruption (PLE). As understanding of phototherapy improves, new therapies (UV- and non-UV-based) are being developed that will modify regulatory T-cells (Treg), interact with (resident) memory T-cells and /or utilize agonists and antagonists as well as antibodies targeting soluble molecules such as cytokines and chemokines, transcription factors, and a variety of membrane-associated receptors.
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Affiliation(s)
- Pablo A Vieyra-Garcia
- Department of Dermatology, Medical University of Graz, Auenbruggerplatz 8, Graz A-8036, Austria.
| | - Peter Wolf
- Department of Dermatology, Medical University of Graz, Auenbruggerplatz 8, Graz A-8036, Austria.
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Lordan R, Tsoupras A, Zabetakis I. The Potential Role of Dietary Platelet-Activating Factor Inhibitors in Cancer Prevention and Treatment. Adv Nutr 2019; 10:148-164. [PMID: 30721934 PMCID: PMC6370273 DOI: 10.1093/advances/nmy090] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/11/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
Cancer is the second leading cause of mortality worldwide. The role of unresolved inflammation in cancer progression and metastasis is well established. Platelet-activating factor (PAF) is a key proinflammatory mediator in the initiation and progression of cancer. Evidence suggests that PAF is integral to suppression of the immune system and promotion of metastasis and tumor growth by altering local angiogenic and cytokine networks. Interactions between PAF and its receptor may have a role in various digestive, skin, and hormone-dependent cancers. Diet plays a critical role in the prevention of cancer and its treatment. Research indicates that the Mediterranean diet may reduce the incidence of several cancers in which dietary PAF inhibitors have a role. Dietary PAF inhibitors such as polar lipids have demonstrated inhibitory effects against the physiological actions of PAF in cancer and other chronic inflammatory conditions in vitro and in vivo. In addition, experimental models of radiotherapy and chemotherapy demonstrate that inhibition of PAF as adjuvant therapy may lead to more favorable outcomes. Although promising, there is limited evidence on the potential benefits of dietary PAF inhibitors on cancer prevention or treatment. Therefore, further extensive research is required to assess the effects of various dietary factors and PAF inhibitors and to elucidate the mechanisms in prevention of cancer progression and metastasis at a molecular level.
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Affiliation(s)
- Ronan Lordan
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Alexandros Tsoupras
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Ioannis Zabetakis
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
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Riaz MS, Kaur A, Shwayat SN, Behboudi S, Kishore U, Pathan AA. Direct Growth Inhibitory Effect of Platelet Activating Factor C-16 and Its Structural Analogs on Mycobacteria. Front Microbiol 2018; 9:1903. [PMID: 30258409 PMCID: PMC6143801 DOI: 10.3389/fmicb.2018.01903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/27/2018] [Indexed: 12/14/2022] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, is one of the leading causes of human deaths due to a single infectious agent. M. tuberculosis infection of the host initiates a local inflammatory response, resulting in the production of a range of inflammatory factors at the site of infection. These inflammatory factors may come in direct contact with M. tuberculosis and immune cells to activate different signaling pathways. One such factor produced in excess during inflammation is a phospholipid compound, Platelet Activating Factor C-16 (PAF C-16). In this study, PAF C-16 was shown to have a direct inhibitory effect on the growth of Mycobacterium bovis BCG (M. bovis BCG) and Mycobacterium smegmatis (M. smegmatis) in a dose- and time-dependent manner. Use of a range of PAF C-16 structural analogs, including the precursor form Lyso-PAF, revealed that small modifications in the structure of PAF C-16 did not alter its mycobacterial growth inhibitory properties. Subsequent experiments suggested that the attachment of aliphatic carbon tail via ether bond to the glycerol backbone of PAF C-16 was likely to play a vital role in its growth inhibition ability against mycobacteria. Fluorescence microscopy and flow cytometry using Propidium iodide (PI) indicated that PAF C-16 treatment had a damaging effect on the cell membrane of M. bovis BCG and M. smegmatis. Furthermore, the growth inhibitory effect of PAF C-16 was partially mitigated by treatment with membrane-stabilizing agents, α-tocopherol and Tween-80, which further suggests that the growth inhibitory effect of PAF C-16 was mediated through bacterial cell membrane damage.
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Affiliation(s)
- Muhammad S Riaz
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom.,Department of Biotechnology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Anuvinder Kaur
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
| | - Suha N Shwayat
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
| | - Shahriar Behboudi
- The Pirbright Institute, Pirbright, United Kingdom.,Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, United Kingdom
| | - Uday Kishore
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
| | - Ansar A Pathan
- College of Health and Life Sciences, Division of Biosciences, Brunel University London, Uxbridge, United Kingdom
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6
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Kim KY. Anti-inflammatory and ECM gene expression modulations of β-eudesmol via NF-κB signaling pathway in normal human dermal fibroblasts. BIOMEDICAL DERMATOLOGY 2018. [DOI: 10.1186/s41702-017-0014-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chen H, Wang J, Liu Z, Yang H, Zhu Y, Zhao M, Liu Y, Yan M. Mitochondrial DNA depletion causes decreased ROS production and resistance to apoptosis. Int J Mol Med 2016; 38:1039-46. [PMID: 27499009 PMCID: PMC5029958 DOI: 10.3892/ijmm.2016.2697] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 06/14/2016] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial DNA (mtDNA) depletion occurs frequently in many diseases including cancer. The present study was designed in order to examine the hypothesis that mtDNA‑depleted cells are resistant to apoptosis and to explore the possible mechanisms responsible for this effect. Parental human osteosarcoma 143B cells and mtDNA‑deficient (Rho˚ or ρ˚) 206 cells (derived from 143B cells) were exposed to different doses of solar-simulated ultraviolet (UV) radiation. The effects of solar irradiation on cell morphology were observed under both light and fluorescence microscopes. Furthermore, apoptosis, mitochondrial membrane potential (MMP) disruption and reactive oxygen species (ROS) production were detected and measured by flow cytometry. In both cell lines, apoptosis and ROS production were clearly increased, whereas MMP was slightly decreased. However, apoptosis and ROS production were reduced in the Rho˚206 cells compared with the 143B cells. We also performed western blot analysis and demonstrated the increased release of cytosolic Cyt c from mitochondria in the 143B cells compared with that in the Rho˚206 cells. Thus, we concluded that Rho˚206 cells exhibit more resistance to solar‑simulated UV radiation‑induced apoptosis at certain doses than 143B cells and this is possibly due to decreased ROS production.
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Affiliation(s)
- Hulin Chen
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
| | - Junling Wang
- Gynecologic Department of Guangzhou Hospital of Integrated Traditional and West Medicine, Guangzhou, Guangdong 510800, P.R. China
| | - Zhongrong Liu
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
| | - Huilan Yang
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
| | - Yingjie Zhu
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
| | - Minling Zhao
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
| | - Yan Liu
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
| | - Miaomiao Yan
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command (Liuhuaqiao Hospital), Guangzhou, Guangdong 510010, P.R. China
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8
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Yan M, Liu Z, Yang H, Li C, Chen H, Liu Y, Zhao M, Zhu Y. Luteolin decreases the UVA‑induced autophagy of human skin fibroblasts by scavenging ROS. Mol Med Rep 2016; 14:1986-92. [PMID: 27430964 PMCID: PMC4991762 DOI: 10.3892/mmr.2016.5517] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 04/22/2016] [Indexed: 11/06/2022] Open
Abstract
Luteolin (LUT) is a flavone, which is universally present as a constituent of traditional Chinese herbs, and certain vegetables and spices, and has been demonstrated to exhibit potent radical scavenging and cytoprotective properties. Although LUT has various beneficial effects on health, the effects of LUT on the protection of skin remain to be fully elucidated. The present study investigated whether LUT can protect human skin fibroblasts (HSFs) from ultraviolet (UV) A irradiation. It was found that, following exposure to different doses of UVA irradiation, the HSFs exhibited autophagy, as observed by fluorescence and transmission electron microscopy, and reactive oxygen species (ROS) bursts, analyzed by flow cytometry, to differing degrees. Following incubation with micromolar concentrations of LUT, ROS production decreased and autophagy gradually declined. In addition, the expression of hypoxia-inducible factor-1α and the classical autophagy-associated proteins, LC3 and Beclin 1 were observed by western blotting. Western blot analysis showed that the expression levels of HIF-1α, LC3-II and Beclin 1 gradually decreased in the UVA-irradiated HSFs following treatment with LUT. These data indicated that UVA-induced autophagy was mediated by ROS, suggesting the possibility of resistance against UV by certain natural antioxidants, including LUT.
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Affiliation(s)
- Miaomiao Yan
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Zhongrong Liu
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Huilan Yang
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Cuihua Li
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Hulin Chen
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Yan Liu
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Minling Zhao
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
| | - Yingjie Zhu
- Department of Dermatology, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, Guangdong 510010, P.R. China
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9
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Damiani E, Ullrich SE. Understanding the connection between platelet-activating factor, a UV-induced lipid mediator of inflammation, immune suppression and skin cancer. Prog Lipid Res 2016; 63:14-27. [PMID: 27073146 DOI: 10.1016/j.plipres.2016.03.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/16/2016] [Accepted: 03/31/2016] [Indexed: 01/08/2023]
Abstract
Lipid mediators of inflammation play important roles in several diseases including skin cancer, the most prevalent type of cancer found in the industrialized world. Ultraviolet (UV) radiation is a complete carcinogen and is the primary cause of skin cancer. UV radiation is also a potent immunosuppressive agent, and UV-induced immunosuppression is a well-known risk factor for skin cancer induction. An essential mediator in this process is the glyercophosphocholine 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine commonly referred to as platelet-activating factor (PAF). PAF is produced by keratinocytes in response to diverse stimuli and exerts its biological effects by binding to a single specific G-protein-coupled receptor (PAF-R) expressed on a variety of cells. This review will attempt to describe how this lipid mediator is involved in transmitting the immunosuppressive signal from the skin to the immune system, starting from its production by keratinocytes, to its role in activating mast cell migration in vivo, and to the mechanisms involved that ultimately lead to immune suppression. Recent findings related to its role in regulating DNA repair and activating epigenetic mechanisms, further pinpoint the importance of this bioactive lipid, which may serve as a critical molecular mediator that links the environment (UVB radiation) to the immune system and the epigenome.
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Affiliation(s)
- Elisabetta Damiani
- Dipartimento di Scienze della Vita e dell'Ambiente, Universita' Politecnica delle Marche, Ancona, Italy
| | - Stephen E Ullrich
- Department of Immunology and The Center for Cancer Immunology Research, The University of Texas Graduate School for Biomedical Sciences at Houston, The University of Texas, MD Anderson Cancer Center, Houston, TX, USA
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Sahu RP. Expression of the platelet-activating factor receptor enhances benzyl isothiocyanate-induced apoptosis in murine and human melanoma cells. Mol Med Rep 2015; 12:394-400. [PMID: 25695262 PMCID: PMC4438923 DOI: 10.3892/mmr.2015.3371] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 11/20/2014] [Indexed: 02/04/2023] Open
Abstract
Melanoma cells often express platelet-activating factor receptor (PAF-R), which has been demonstrated to increase metastatic behavior. However, the effect of PAF-R on the responsiveness of melanoma to naturally occurring cytotoxic agents remains to be elucidated. The present study aimed to determine the relative cytotoxicity and mechanism of benzyl isothiocyanate (BITC), a component of cruciferous vegetables, in melanoma cells expressing PAF-R. To evaluate the importance of PAF-R signaling in melanoma cell growth, PAF-R-negative murine B16F10 cells were transduced with a retrovirus containing the cDNA for PAF-R to generate cells stably expressing PAF-R (B16-PAF-R) or an empty vector (MSCV) to generate PAF-R-deficient B16-MSCV control cells. Activation of PAF-R, using the PAF-R agonist, 1-hexadecyl-2-N-methylcarbamoyl-3-glycerophosphocholine, induced an increase in the proliferation of B16-PAF-R cells compared with the B16-MSCV cells. Reverse transcription quantitative polymerase chain reaction revealed the presence of functional PAF-R in human melanoma SK23MEL cells, but not in SK5MEL cells. The present study investigated the effect of BITC treatments on the survival of murine and human melanoma cells, in the presence or absence of functional PAF-R. The results revealed that treatment with BITC decreased the survival rate of the PAF-R-positive and negative murine and human melanoma cells. However, the expression of PAF-R substantially augmented BITC-mediated cytotoxicity in the PAF-R-positive cells at lower concentrations compared with the PAF-R-negative cells. In order to determine the underlying mechanism, flow cytometric analysis was used, which demonstrated a significant increase in the generation of reactive oxygen species (ROS) in the B16-PAF-R cells compared with the B16-MSCV cells, which enhanced apoptosis by BITC, as measured by increased caspase-3/7 luminescence. Notably, the BITC-mediated decreased cell survival rate, increased ROS and increased apoptosis in the B16-PAF-R cells were significantly attenuated by the antioxidant, vitamin C, indicating ROS involvement. Additionally, the WEB2086 PAF-R antagonist, inhibited the BITC-mediated enhancement of apoptosis in the B16-PAF-R cells, indicating a role for PAF-R-signaling in the BITC-mediated effects. These findings indicated that the selectivity of BITC towards PAF-R in melanoma offers a promising chemopreventive agent for PAF-R-positive melanoma treatment.
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Affiliation(s)
- Ravi Prakash Sahu
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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11
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Abstract
The ultraviolet (UV) radiation contained in sunlight is a powerful immune suppressant. While exposure to UV is best known for its ability to cause skin cancer, it is also associated with protection against a range of autoimmune diseases, particularly multiple sclerosis (MS). Although the precise mechanism by which sunlight affords protection from MS remains to be determined, some have hypothesised that UV immunosuppression explains the "latitude-gradient effect" associated with MS. By stimulating the release of soluble factors in exposed skin, UV activates immune suppressive pathways that culminate in the induction of regulatory cells in distant tissues. Each and every one of the immune suppressive cells and molecules activated by UV exposure are potential targets for treating and preventing MS. A thorough understanding of the mechanisms involved is therefore required if we are to realise the therapeutic potential of photoimmunology.
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Affiliation(s)
- Felix Marsh-Wakefield
- Cellular Photoimmunology Group, Discipline of Infectious Diseases and Immunology, Sydney Medical School, University of Sydney, Camperdown, Australia.,Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.,Discipline of Dermatology, Bosch Institute, Sydney Medical School, University of Sydney, Camperdown, Australia
| | - Scott N Byrne
- Cellular Photoimmunology Group, Discipline of Infectious Diseases and Immunology, Sydney Medical School, University of Sydney, Camperdown, Australia. .,Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia. .,Discipline of Dermatology, Bosch Institute, Sydney Medical School, University of Sydney, Camperdown, Australia. .,Infectious Diseases and Immunology, Level 5 (East), The Charles Perkins Centre Hub (D17), University of Sydney, Camperdown, NSW, 2006, Australia.
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12
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13
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Platelet-activating factor induces proliferation in differentiated keratinocytes. Mol Cell Biochem 2013; 384:83-94. [PMID: 23975504 DOI: 10.1007/s11010-013-1784-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 08/09/2013] [Indexed: 10/26/2022]
Abstract
Increased levels of platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) are found in several inflammatory dermatoses, but PAF's exact role in epidermis is uncertain. In order to better understand the physiological consequences of excess PAF production in epidermis, we examined the gene regulatory effects of PAF short-term stimulation in differentiated HaCaT keratinocytes by transcriptional profiling. Even though PAF induces COX2 expression, we found that PAF regulates only few genes associated with inflammation in differentiated keratinocytes. Rather, we show that natural PAF rapidly regulates genes involved in proliferation, (anti)-apoptosis and migration, all sub-processes of re-epithelialization and wound healing. Moreover, profiling of phosphorylated kinases, cellular wound-scratch experiments, resazurin assay and flow cytometry cell cycle phase analysis all support a role for PAF in keratinocyte proliferation and epidermal re-epithelialization. In conclusion, these results suggest that PAF acts as an activator of proliferation and may, therefore, function as a connector between inflammation and proliferation in differentiated keratinocytes.
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14
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Shin MH, Park R, Nojima H, Kim HC, Kim YK, Chung JH. Atomic hydrogen surrounded by water molecules, H(H2O)m, modulates basal and UV-induced gene expressions in human skin in vivo. PLoS One 2013; 8:e61696. [PMID: 23637886 PMCID: PMC3634861 DOI: 10.1371/journal.pone.0061696] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 03/12/2013] [Indexed: 01/16/2023] Open
Abstract
Recently, there has been much effort to find effective ingredients which can prevent or retard cutaneous skin aging after topical or systemic use. Here, we investigated the effects of the atomic hydrogen surrounded by water molecules, H(H2O)m, on acute UV-induced responses and as well as skin aging. Interestingly, we observed that H(H2O)m application to human skin prevented UV-induced erythema and DNA damage. And H(H2O)m significantly prevented UV-induced MMP-1, COX-2, IL-6 and IL-1β mRNA expressions in human skin in vivo. We found that H(H2O)m prevented UV-induced ROS generation and inhibited UV-induced MMP-1, COX-2 and IL-6 expressions, and UV-induced JNK and c-Jun phosphorylation in HaCaT cells. Next, we investigated the effects of H(H2O)m on intrinsically aged or photoaged skin of elderly subjects. In intrinsically aged skin, H(H2O)m application significantly reduced constitutive expressions of MMP-1, IL-6, and IL-1β mRNA. Additionally, H(H2O)m significantly increased procollagen mRNA and also decreased MMP-1 and IL-6 mRNA expressions in photoaged facial skin. These results demonstrated that local application of H(H2O)m may prevent UV-induced skin inflammation and can modulate intrinsic skin aging and photoaging processes. Therefore, we suggest that modifying the atmospheric gas environment within a room may be a new way to regulate skin functions or skin aging.
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Affiliation(s)
- Mi Hee Shin
- Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea
- Laboratory of Cutaneous Aging Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Korea
| | - Raeeun Park
- R&D Team, Samsung Electronics CO., LTD, Suwon, Korea
| | - Hideo Nojima
- R&D Team, Samsung Electronics CO., LTD, Suwon, Korea
| | | | - Yeon Kyung Kim
- Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea
- Laboratory of Cutaneous Aging Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Korea
| | - Jin Ho Chung
- Department of Dermatology, Seoul National University College of Medicine, Seoul, Korea
- Laboratory of Cutaneous Aging Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
- Institute of Human-Environment Interface Biology, Medical Research Center, Seoul National University, Seoul, Korea
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15
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Petho G, Reeh PW. Sensory and signaling mechanisms of bradykinin, eicosanoids, platelet-activating factor, and nitric oxide in peripheral nociceptors. Physiol Rev 2013; 92:1699-775. [PMID: 23073630 DOI: 10.1152/physrev.00048.2010] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Peripheral mediators can contribute to the development and maintenance of inflammatory and neuropathic pain and its concomitants (hyperalgesia and allodynia) via two mechanisms. Activation or excitation by these substances of nociceptive nerve endings or fibers implicates generation of action potentials which then travel to the central nervous system and may induce pain sensation. Sensitization of nociceptors refers to their increased responsiveness to either thermal, mechanical, or chemical stimuli that may be translated to corresponding hyperalgesias. This review aims to give an account of the excitatory and sensitizing actions of inflammatory mediators including bradykinin, prostaglandins, thromboxanes, leukotrienes, platelet-activating factor, and nitric oxide on nociceptive primary afferent neurons. Manifestations, receptor molecules, and intracellular signaling mechanisms of the effects of these mediators are discussed in detail. With regard to signaling, most data reported have been obtained from transfected nonneuronal cells and somata of cultured sensory neurons as these structures are more accessible to direct study of sensory and signal transduction. The peripheral processes of sensory neurons, where painful stimuli actually affect the nociceptors in vivo, show marked differences with respect to biophysics, ultrastructure, and equipment with receptors and ion channels compared with cellular models. Therefore, an effort was made to highlight signaling mechanisms for which supporting data from molecular, cellular, and behavioral models are consistent with findings that reflect properties of peripheral nociceptive nerve endings. Identified molecular elements of these signaling pathways may serve as validated targets for development of novel types of analgesic drugs.
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Affiliation(s)
- Gábor Petho
- Pharmacodynamics Unit, Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, Pécs, Hungary
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16
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Byrne SN, Beaugie C, O'Sullivan C, Leighton S, Halliday GM. The immune-modulating cytokine and endogenous Alarmin interleukin-33 is upregulated in skin exposed to inflammatory UVB radiation. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:211-22. [PMID: 21703403 DOI: 10.1016/j.ajpath.2011.03.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 02/08/2011] [Accepted: 03/14/2011] [Indexed: 10/18/2022]
Abstract
The cellular and molecular mechanisms by which UV radiation modulates inflammation and immunity while simultaneously maintaining skin homeostasis is complex and not completely understood. Similar to the effects of UV, IL-33 has potent immune-modulating properties that are mediated by the downstream induction of cytokines and chemokines. We have discovered that exposure of mice in vivo or human skin samples ex vivo to inflammatory doses of UVB induced IL-33 expression within the epidermal and dermal skin layers. Using a combination of murine cell lines and primary human cells, we demonstrate that both UV and the oxidized lipid platelet activating factor induce IL-33 expression in keratinocytes and dermal fibroblasts. Highlighting the significance of these results, we found that administering IL-33 to mice in vivo suppressed the induction of Th1-mediated contact hypersensitivity responses. This may have consequences for skin cancer growth because UV-induced squamous cell carcinomas that evade immunological destruction were found to express significantly higher levels of IL-33. Finally, we demonstrate that dermal mast cells and skin-infiltrating neutrophils closely associate with UV-induced IL-33-expressing fibroblasts. Our results therefore identify and support a role for IL-33 as an important early danger signal produced in response to inflammation-inducing UV radiation.
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Affiliation(s)
- Scott Napier Byrne
- Cellular Immunology Group, Department of Infectious Diseases and Immunology, Sydney Medical School, University of Sydney, New South Wales, Australia.
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17
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Puebla-Osorio N, Miyahara Y, Coimbatore S, Limón-Flores AY, Kazimi N, Ullrich SE, Zhu C. Induction of B-cell lymphoma by UVB radiation in p53 haploinsufficient mice. BMC Cancer 2011; 11:36. [PMID: 21269511 PMCID: PMC3041776 DOI: 10.1186/1471-2407-11-36] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 01/26/2011] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The incidence of non-Hodgkin's lymphoma has increased over recent years. The exact etiology of lymphoma remains unknown. Ultraviolet light exposure has been associated with the development of internal lymphoid malignancies and some reports suggest that it may play a role in the development of lymphoma in humans. Here we describe the characterization and progression of lymphoma in p53 heterozygous mice exposed to UVB irradiation. METHODS UVB-irradiated p53+/- mice developed enlargement of the spleen. Isolated spleen cells were transplanted into Rag deficient hosts. The UV-induced tumor cells were analyzed by flow cytometry. The tumor cells were tagged with GFP to study their metastatic potential. SKY and karyotypic analysis were carried out for the detection of chromosomal abnormalities. Functional assays included in vitro class switch recombination assay, immunoglobulin rearrangement assay, as well as cytokine profiling. RESULTS UVB-exposed mice showed enlargement of the spleen and lymph nodes. Cells transplanted into Rag deficient mice developed aggressive tumors that infiltrated the lymph nodes, the spleen and the bone marrow. The tumor cells did not grow in immune competent syngeneic C57Bl/6 mice yet showed a modest growth in UV-irradiated B6 mice. Phenotypic analysis of these tumor cells revealed these cells are positive for B cell markers CD19+, CD5+, B220+, IgM+ and negative for T cell, NK or dendritic cell markers. The UV-induced tumor cells underwent robust in vitro immunoglobulin class switch recombination in response to lipopolysaccharide. Cytogenetic analysis revealed a t(14;19) translocation and trisomy of chromosome 6. These tumor cells secret IL-10, which can promote tumor growth and cause systemic immunosuppression. CONCLUSION UV-irradiated p53+/- mice developed lymphoid tumors that corresponded to a mature B cell lymphoma. Our results suggest that an indirect mechanism is involved in the development of internal tumors after chronic exposure to UV light. The induction of B cell lymphoma in UV-irradiated p53 heterozygous mice may provide a useful model for lymphoma development in humans.
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Affiliation(s)
- Nahum Puebla-Osorio
- Department of Immunology and the Center for Cancer Immunology Research, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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18
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Kaneko K, Travers JB, Matsui MS, Young AR, Norval M, Walker SL. cis-Urocanic Acid Stimulates Primary Human Keratinocytes Independently of Serotonin or Platelet-Activating Factor Receptors. J Invest Dermatol 2009; 129:2567-73. [DOI: 10.1038/jid.2009.129] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Sreevidya CS, Fukunaga A, Khaskhely NM, Masaki T, Ono R, Nishigori C, Ullrich SE. Agents that reverse UV-Induced immune suppression and photocarcinogenesis affect DNA repair. J Invest Dermatol 2009; 130:1428-37. [PMID: 19829299 DOI: 10.1038/jid.2009.329] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
UV exposure induces skin cancer, in part, by inducing immune suppression. Repairing DNA damage, neutralizing the activity of cis-urocanic acid, and reversing oxidative stress abrogate UV-induced immune suppression and skin cancer induction, suggesting that DNA, UCA, and lipid photo-oxidation serve as UV photoreceptors. What is not clear is whether signaling through each of these different photoreceptors activates independent pathways to induce biological effects or whether there is a common checkpoint where these pathways converge. Here, we show that agents known to reverse photocarcinogenesis and photoimmune suppression, such as platelet-activating factor (PAF) and serotonin (5-HT) receptor antagonists, regulate DNA repair. Pyrimidine dimer repair was accelerated in UV-irradiated mice injected with PAF and 5-HT receptor antagonists. Nucleotide excision repair (NER), as measured by unscheduled DNA synthesis, was accelerated by PAF and 5-HT receptor antagonists. Injecting PAF and 5-HT receptor antagonists into UV-irradiated Xeroderma pigmentosum complementation group A-deficient mice, which lack the enzymes responsible for NER, did not accelerate photoproduct repair. Similarly, UV-induced formation of 8-oxo-deoxyguanosine was reduced by PAF and 5-HT receptor antagonists. We conclude that PAF and 5-HT receptor antagonists accelerate DNA repair caused by UV radiation, which prevents immune suppression and interferes with photocarcinogenesis.
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Affiliation(s)
- Coimbatore S Sreevidya
- Department of Immunology and the Center for Cancer Immunology Research, The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
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20
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Yao Y, Wolverton JE, Zhang Q, Marathe GK, Al-Hassani M, Konger RL, Travers JB. Ultraviolet B radiation generated platelet-activating factor receptor agonist formation involves EGF-R-mediated reactive oxygen species. THE JOURNAL OF IMMUNOLOGY 2009; 182:2842-8. [PMID: 19234179 DOI: 10.4049/jimmunol.0802689] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recent studies have implicated the lipid mediator platelet-activating factor (PAF) in UVB-mediated systemic immunosuppression known to be a major cause for skin cancers. Previously, our group has demonstrated that UVB irradiation triggers the production of PAF and oxidized glycerophosphocholines that act as PAF-receptor (PAF-R) agonists. The present studies explored the mechanisms by which UVB generates PAF-R agonists. UVB irradiation of human epidermal KB cells resulted in both increased levels of reactive oxygen species (ROS) and PAF-R agonistic activity. Pretreatment of KB cells with antioxidants vitamin C and N-acetylcysteine or the pharmacological inhibitor PD168393 specific for the epidermal growth factor receptor all inhibited UVB-induced ROS as well as PAF-R agonists, yet had no effect on fMLP-mediated PAF-R agonist production. In addition, in vivo production of PAF-R agonists from UVB-irradiated mouse skin was blocked by both systemic vitamin C administration and topical PD168393 application. Moreover, both vitamin C and PD168393 abolished UVB-mediated but not the PAF-R agonist 1-hexadecyl-2-N-methylcarbamoyl glycerophosphocholine-mediated immunosuppression as measured by the inhibition of delayed type contact hypersensitivity to the chemical dinitrofluorobenzene. These studies suggest that UVB-induced systemic immunosuppression is due to epidermal growth factor receptor-mediated ROS which results in PAF-R agonist formation.
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Affiliation(s)
- Yongxue Yao
- Department of Dermatology, and the Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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21
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Fukunaga A, Khaskhely NM, Sreevidya CS, Byrne SN, Ullrich SE. Dermal dendritic cells, and not Langerhans cells, play an essential role in inducing an immune response. THE JOURNAL OF IMMUNOLOGY 2008; 180:3057-64. [PMID: 18292528 DOI: 10.4049/jimmunol.180.5.3057] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Langerhans cells (LCs) serve as epidermal sentinels of the adaptive immune system. Conventional wisdom suggests that LCs encounter Ag in the skin and then migrate to the draining lymph nodes, where the Ag is presented to T cells, thus initiating an immune response. Platelet-activating factor (PAF) is a phospholipid mediator with potent biological effects. During inflammation, PAF mediates recruitment of leukocytes to inflammatory sites. We herein tested a hypothesis that PAF induces LC migration. Applying 2,4-dinitro-1-fluorobenzene (DNFB) to wild-type mice activated LC migration. In contrast, applying DNFB to PAF receptor-deficient mice or mice injected with PAF receptor antagonists failed to induce LC migration. Moreover, after FITC application the appearance of hapten-laden LCs (FITC+, CD11c+, Langerin+) in the lymph nodes of PAF receptor-deficient mice was significantly depressed compared with that found in wild-type mice. LC chimerism indicates that the PAF receptor on keratinocytes but not LCs is responsible for LC migration. Contrary to the diminution of LC migration in PAF receptor-deficient mice, we did not observe any difference in the migration of hapten-laden dermal dendritic cells (FITC+, CD11c+, Langerin-) into the lymph nodes of PAF receptor-deficient mice. Additionally, the contact hypersensitivity response generated in wild-type or PAF receptor-deficient mice was identical. Finally, dermal dendritic cells, but not LCs isolated from the draining lymph nodes after hapten application, activated T cell proliferation. These findings suggest that LC migration may not be responsible for the generation of contact hypersensitivity and that dermal dendritic cells may play a more important role.
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Affiliation(s)
- Atsushi Fukunaga
- Department of Immunology and Center for Cancer Immunology Research, M.D. Anderson Cancer Center, University of Texas, Houston, TX 77030, USA
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22
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Involvement of platelet-activating factor in ultraviolet B-induced hyperalgesia. J Invest Dermatol 2008; 129:167-74. [PMID: 18580961 DOI: 10.1038/jid.2008.181] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ultraviolet B (UVB) radiation causes cutaneous inflammation. One important clinical consequence of UVB-induced inflammation is increased pain or hyperalgesia, which is likely mediated by enhanced sensitivity of cutaneous sensory neurons. Previous studies have demonstrated that UVB radiation generates the lipid mediator, platelet-activating factor (PAF), as well as oxidized phospholipids that act as PAF-mimetics. These substances exert effects through the PAF receptor (PAF-R). This study was designed to assess whether PAF-R is involved in UVB-induced hyperalgesia. Intradermal injection of carbamoyl PAF (CPAF; 1-hexadecyl-2-N-methylcarbamoyl glycerophosphocholine) resulted in an enhanced response to mechanical stimuli in wild-type mice but not in PAF-R knockout (KO) mice. There was no significant change in paw withdrawal to noxious thermal stimuli in either genotype after intradermal injection of CPAF. Exposure of the hind paw to 1,500 J m(-2) UVB radiation caused an increased sensitivity to both mechanical and thermal stimulation in wild-type mice but not in PAF-R KO mice. The thermal hyperalgesia caused by UVB irradiation was inhibited in mice that lacked PAF-R in bone marrow-derived cells. These data demonstrate that the PAF-R is important for UVB-induced hyperalgesia. Further investigation of the role of PAF-R signaling in UVB-induced hyperalgesia could provide better understanding of the pathological processes initiated by UVB-induced skin damage.
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23
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Sreevidya CS, Khaskhely NM, Fukunaga A, Khaskina P, Ullrich SE. Inhibition of photocarcinogenesis by platelet-activating factor or serotonin receptor antagonists. Cancer Res 2008; 68:3978-84. [PMID: 18483284 DOI: 10.1158/0008-5472.can-07-6132] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The UV radiation in sunlight is the primary cause of nonmelanoma skin cancer. Moreover, UV exposure induces immune suppression. Early steps in the cascade of events leading to immune suppression are the binding of UV-induced platelet-activating factor (PAF) to its receptor and the binding of cis-urocanic acid, a photoreceptor for UVB radiation, to the serotonin (5-HT(2A)) receptor. Here, we tested the hypothesis that blocking the binding of PAF and 5-HT(2A) to their receptors would also block skin cancer induction. Hairless mice were injected with PAF or serotonin receptor antagonists and then exposed to solar-simulated UV radiation. We noted a significant and substantial decrease in skin cancer incidence in mice treated with the PAF or 5-HT(2A) receptor antagonists. Also, the PAF and/or serotonin receptor antagonists blocked skin cancer progression. The PAF and serotonin receptor antagonists worked in a synergistic fashion to block skin cancer induction. We also measured the effect that injecting PAF and 5-HT(2A) receptor antagonists had on UV-induced skin damage after a single UV exposure. We noted a significant decrease in UV-induced hypertrophy, sunburn cell formation, and apoptosis when the mice were injected with PAF and/or 5-HT(2A) receptor antagonists. These data indicate that treating UV-irradiated mice with PAF and 5-HT(2A) receptor antagonists blocks skin cancer induction in vivo, in part by reversing UV-induced damage to the skin and by preventing the induction of immune suppression.
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Affiliation(s)
- Coimbatore S Sreevidya
- Department of Immunology and the Center for Cancer Immunology Research, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
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24
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Bossi O, Gartsbein M, Leitges M, Kuroki T, Grossman S, Tennenbaum T. UV irradiation increases ROS production via PKCδ signaling in primary murine fibroblasts. J Cell Biochem 2008; 105:194-207. [DOI: 10.1002/jcb.21817] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Oxidized glycerophosphocholines as biologically active mediators for ultraviolet radiation-mediated effects. Prostaglandins Other Lipid Mediat 2008; 87:1-8. [PMID: 18555720 DOI: 10.1016/j.prostaglandins.2008.04.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 04/21/2008] [Accepted: 04/22/2008] [Indexed: 10/22/2022]
Abstract
Ultraviolet light radiation (UVR) has profound effects upon human skin. Yet, the exact targets for UVR are unclear. Inasmuch as UVR is a known pro-oxidative stressor, one potential target for UVR could be oxidatively modified glycerophosphocholines (GPC). Importantly, recent studies demonstrate that these oxidized GPCs (ox-GPC) are potent agonists for the platelet-activating factor receptor and peroxisome proliferator-activated receptor gamma. This review discusses these new biologically active lipids and their down-stream receptor targets that provide a unique system of biosensors for detecting and responding to UVR photo-oxidation.
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26
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Mechanisms of Korean red ginseng and herb extracts(KTNG0345) for anti-wrinkle activity. J Ginseng Res 2008. [DOI: 10.5142/jgr.2008.32.1.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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27
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Melnikova VO, Villares GJ, Bar-Eli M. Emerging roles of PAR-1 and PAFR in melanoma metastasis. CANCER MICROENVIRONMENT 2008; 1:103-11. [PMID: 19308689 PMCID: PMC2654348 DOI: 10.1007/s12307-008-0002-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 01/10/2008] [Indexed: 12/21/2022]
Abstract
Melanoma growth, angiogenesis and metastatic progression are strongly promoted by the inflammatory tumor microenvironment due to high levels of cytokine and chemokine secretion by the recruited inflammatory and stromal cells. In addition, platelets and molecular components of procoagulant pathways have been recently emerging as critical players of tumor growth and metastasis. In particular, thrombin, through the activity of its receptor protease-activated receptor-1 (PAR-1), regulates tumor cell adhesion to platelets and endothelial cells, stimulates tumor angiogenesis, and promotes tumor growth and metastasis. Notably, in many tumor types including melanoma, PAR-1 expression directly correlates with their metastatic phenotype and is directly responsible for the expression of interleukin-8, matrix metalloproteinase-2 (MMP-2), vascular endothelial growth factor, platelet-derived growth factor, and integrins. Another proinflammatory receptor–ligand pair, platelet-activating factor (PAF) and its receptor (PAFR), have been shown to act as important modulators of tumor cell adhesion to endothelial cells, angiogenesis, tumor growth and metastasis. PAF is a bioactive lipid produced by a variety of cells from membrane glycerophospholipids in the same reaction that releases arachidonic acid, and can be secreted by platelets, inflammatory cells, keratinocytes and endothelial cells. We have demonstrated that in metastatic melanoma cells, PAF stimulates the phosphorylation of cyclic adenosine monophosphate response element-binding protein (CREB) and activating transcription factor 1 (ATF-1), which results in overexpression of MMP-2 and membrane type 1-MMP (membrane type 1-MMP). Since only metastatic melanoma cells overexpress CREB/ATF-1, we propose that metastatic melanoma cells are better equipped than their non-metastatic counterparts to respond to PAF within the tumor microenvironment. The evidence supporting the hypothesis that the two G-protein coupled receptors, PAR-1 and PAFR, contribute to the acquisition of the metastatic phenotype of melanoma is presented and discussed.
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Affiliation(s)
- Vladislava O Melnikova
- Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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28
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Melnikova V, Bar-Eli M. Inflammation and melanoma growth and metastasis: the role of platelet-activating factor (PAF) and its receptor. Cancer Metastasis Rev 2008; 26:359-71. [PMID: 17721743 DOI: 10.1007/s10555-007-9092-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
An inflammatory tumor microenvironment fosters tumor growth, angiogenesis and metastatic progression. Platelet-activating factor (PAF) is an inflammatory biolipid produced from membrane glycerophospholipids. Through the activity of its G-protein coupled receptor, PAF triggers a variety of pathological reactions including tumor neo-angiogenesis. Several groups have demonstrated that inhibiting PAF-PAF receptor pathway at the level of a ligand or receptor results in an effective inhibition of experimental tumor growth and metastasis. In particular, our group has recently demonstrated that PAF receptor antagonists can effectively inhibit the metastatic potential of human melanoma cells in nude mice. Furthermore, we showed that PAF stimulated the phosphorylation of CREB and ATF-1 in metastatic melanoma cells, which resulted in overexpression of MMP-2 and MT1-MMP. Our data indicate that PAF acts as a promoter of melanoma metastasis in vivo. Since only metastatic melanoma cells overexpress CREB/ATF-1, we propose that these cells are better equipped to respond to PAF within the tumor microenvironment when compared to their non-metastatic counterparts.
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Affiliation(s)
- Vladislava Melnikova
- Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, P.O. Box 173, Houston, TX 77030, USA
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29
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Rockel N, Esser C, Grether-Beck S, Warskulat U, Flögel U, Schwarz A, Schwarz T, Yarosh D, Häussinger D, Krutmann J. The osmolyte taurine protects against ultraviolet B radiation-induced immunosuppression. THE JOURNAL OF IMMUNOLOGY 2007; 179:3604-12. [PMID: 17785795 DOI: 10.4049/jimmunol.179.6.3604] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Organic osmolytes, such as taurine, are involved in cell volume homeostasis and cell protection. Epidermal keratinocytes possess an osmolyte strategy, i.e., they take up taurine upon hyperosmotic stress and express the corresponding transporter TAUT. UVB irradiation also triggers taurine uptake and TAUT expression in this cell type. We therefore asked whether taurine plays a role in photoprotection. By using a TAUT-deficient mouse model, lack of taurine in the skin was found to cause a significantly higher sensitivity to UVB-induced immunosuppression. This was not due to an increased generation or decreased repair of UVB-induced DNA photoproducts in the skin of these animals. Instead, decreased skin taurine levels were associated with an increased formation of the soluble immunosuppressive molecule platelet-activating factor (PAF) from the membranes of UVB-irradiated epidermal cells. Blocking PAF activity in taut-deficient mice with a PAF receptor antagonist abrogated their increased sensitivity to UVB-induced immunosuppression. Moreover, taut -/- mice were more sensitive to PAF-mediated immunosuppression than taut +/+ mice. These data suggest that taurine uptake by epidermal cells prevents undue PAF formation, and thereby photoimmunosuppression. Thus, similar to nucleotide excision repair, taurine uptake is critically involved in photoprotection of the skin.
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Affiliation(s)
- Nicole Rockel
- Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Düsseldorf, Germany
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30
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Augmentation of UVB radiation-mediated early gene expression by the epidermal platelet-activating factor receptor. J Invest Dermatol 2007; 128:455-60. [PMID: 17928889 DOI: 10.1038/sj.jid.5701083] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
UVB radiation (UVB) is a known inducer of many biological changes in human skin, and triggers the production of glycerophosphocholines that act as platelet-activating factor (PAF) agonists. To gain a better insight into the role of the epidermal PAF receptor (PAF-R) in UVB-mediated gene expression, Affymetrix oligonucleotide microarrays were used to compare mRNA expression in the PAF-R-negative epithelial cell line KB-expressing PAF-Rs (KBP) with that in KB cells transduced with a vector control (KBM). Total RNA was isolated from KB cells 1 hour after treatment with a PAF-R agonist or UVB irradiation. Treatment of KBP with PAF agonist resulted in altered expression of 220 genes, including cytokines and growth factors. UVB irradiation of KB cells resulted in an increased expression of genes in both cell types. A panel of genes including cytokines CCL20 (MIP3alpha) and tumor necrosis factor-alpha (TNF-alpha) were upregulated selectively in KBP cells and are also selectively upregulated in response to PAF agonist. Consistent with these in vitro findings, UVB irradiation resulted in increased levels of epidermal CCL20 and TNF-alpha mRNA in wild-type over PAF-R-deficient mice in vivo. These studies provide evidence that the epidermal PAF-R can modulate UVB-mediated early gene expression.
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Abstract
The ultraviolet (UV) radiation in sunlight induces skin cancer development. Skin cancer is the most common form of human neoplasia. Estimates suggest that in excess of 1.5 million new cases of skin cancer (www.cancer.org/statistics) will be diagnosed in the United States this year. Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer, and the cost of treating skin cancer in the United States (both melanoma and non-melanoma skin cancer) is estimated to be in excess of $2.9 billion a year. In addition to causing skin cancer, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. Recent studies in my laboratory have focused on understanding the initial molecular events that induce immune suppression. We made two novel observations: first UV-induced keratinocyte-derived platelet activating factor plays a role in the induction of immune suppression. Second, cis-urocanic acid, a skin-derived immunosuppressive compound mediates immune suppression by binding to serotonin receptors on target cells. Recent findings suggest that blocking the binding of these compounds to their receptors not only inhibits UV-induced immune suppression but it also interferes with skin cancer induction.
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Affiliation(s)
- Stephen E Ullrich
- Department of Immunology and the Center for Cancer Immunology Research, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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32
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Landis M, Yi Q, Hyatt AM, Travers AR, Lewis DA, Travers JB. Involvement of P38 MAP kinase in the augmentation of UVB-mediated apoptosis via the epidermal platelet-activating factor receptor. Arch Dermatol Res 2007; 299:263-6. [PMID: 17437119 DOI: 10.1007/s00403-007-0753-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 03/06/2007] [Indexed: 10/23/2022]
Abstract
Platelet-activating factor (PAF) is a group of phosphocholines with various biological effects, which are mediated by the PAF receptor (PAF-R). Our previous studies have demonstrated that ultraviolet B radiation (UVB) is a potent stimulus for PAF production, and that the presence of the PAF-R on epithelial cells results in an augmentation of UVB-induced apoptosis. Inasmuch as PAF-R activation results in numerous signal transduction pathways, the present study was designed to characterize the signal transduction pathway responsible for PAF-R-mediated enhanced UVB-induced cytotoxicity. Using a model system of PAF-R-negative and -positive epithelioid KB cells, we demonstrate that inhibitors of p38 MAP kinase block the augmentation of UVB-mediated apoptosis seen in PAF-R-positive KB cells. In contrast, pharmacological and/or molecular inhibition of other pathways linked to PAF-R activation including ERK MAP kinase and NFkappaB do not affect PAF-R-mediated cytotoxicity. This study demonstrates the important role that p38 MAP kinase plays in PAF-R-mediated augmentation of UVB cytotoxicity.
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Affiliation(s)
- Megan Landis
- Department of Dermatology, H. B. Wells Center for Pediatric Research, James Whitcomb Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Walterscheid JP, Nghiem DX, Kazimi N, Nutt LK, McConkey DJ, Norval M, Ullrich SE. Cis-urocanic acid, a sunlight-induced immunosuppressive factor, activates immune suppression via the 5-HT2A receptor. Proc Natl Acad Sci U S A 2006; 103:17420-5. [PMID: 17085585 PMCID: PMC1859944 DOI: 10.1073/pnas.0603119103] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exposure to UV radiation induces skin cancer and suppresses the immune response. To induce immune suppression, the electromagnetic energy of UV radiation must be absorbed by an epidermal photoreceptor and converted into a biologically recognizable signal. Two photoreceptors have been recognized: DNA and trans-urocanic acid (UCA). Trans-UCA is normally found in the outermost layer of skin and isomerizes to the cis isomer upon exposure to UV radiation. Although UCA was identified as a UV photoreceptor years ago, and many have documented its ability to induce immune suppression, its exact mode of action remains elusive. Particularly vexing has been the identity of the molecular pathway by which cis-UCA mediates immune suppression. Here we provide evidence that cis-UCA binds to the serotonin [5-hydroxytryptamine (5-HT)] receptor with relatively high affinity (Kd = 4.6 nM). Anti-cis-UCA antibody precipitates radiolabeled 5-HT, and the binding is inhibited by excess 5-HT and/or excess cis-UCA. Similarly, anti-5-HT antibody precipitates radiolabeled cis-UCA, and the binding is inhibited by excess 5-HT or excess cis-UCA. Calcium mobilization was activated when a mouse fibroblast line, stably transfected with the human 5-HT2A receptor, was treated with cis-UCA. Cis-UCA-induced calcium mobilization was blocked with a selective 5-HT2A receptor antagonist. UV- and cis-UCA-induced immune suppression was blocked by antiserotonin antibodies or by treating the mice with 5-HT2A receptor antagonists. Our findings identify cis-UCA as a serotonin receptor ligand and indicate that the immunosuppressive effects of cis-UCA and UV radiation are mediated by activation of the 5-HT2A receptor.
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Affiliation(s)
- Jeffrey P. Walterscheid
- *Department of Immunology and Center for Cancer Immunology Research and
- Graduate School of Biomedical Sciences, University of Texas, Houston, TX 77030; and
| | - Dat X. Nghiem
- *Department of Immunology and Center for Cancer Immunology Research and
- Graduate School of Biomedical Sciences, University of Texas, Houston, TX 77030; and
| | - Nasser Kazimi
- *Department of Immunology and Center for Cancer Immunology Research and
| | - Leta K. Nutt
- Department of Cancer Biology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
- Graduate School of Biomedical Sciences, University of Texas, Houston, TX 77030; and
| | - David J. McConkey
- Department of Cancer Biology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
- Graduate School of Biomedical Sciences, University of Texas, Houston, TX 77030; and
| | - Mary Norval
- Medical Microbiology, University of Edinburgh Medical School, Edinburgh EH8 9AG, Scotland
| | - Stephen E. Ullrich
- *Department of Immunology and Center for Cancer Immunology Research and
- Graduate School of Biomedical Sciences, University of Texas, Houston, TX 77030; and
- To whom correspondence should be addressed at:
Department of Immunology/Unit 902, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030. E-mail:
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Matsumura Y, Byrne SN, Nghiem DX, Miyahara Y, Ullrich SE. A role for inflammatory mediators in the induction of immunoregulatory B cells. THE JOURNAL OF IMMUNOLOGY 2006; 177:4810-7. [PMID: 16982922 PMCID: PMC1579249 DOI: 10.4049/jimmunol.177.7.4810] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
UV exposure suppresses the immune response to a variety of microbial, fungal, and viral Ags. In addition, UV radiation is a complete carcinogen and the immune suppression induced by UV radiation is a major risk factor for skin cancer induction. In this study, we examined the mechanisms underlying the induction of immune suppression and tolerance induction by UV radiation. Transferring lymph nodes cells from UV-irradiated, FITC-sensitized mice into normal recipients transferred immune tolerance. Contrary to expectations, the cell responsible was an FITC(+), IL-10-secreting, CD19(+), B220(+) B cell. Because the lipid mediator of inflammation, platelet-activating factor (PAF) is released by UV-irradiated keratinocytes and is essential for the induction of immune suppression, we determined its role in tolerance induction. When UV-irradiated mice were injected with PCA 4248, a selective PAF receptor (PAFR) antagonist, transfer of tolerance was suppressed. However, immune suppression was not transferred when FITC(+) cells from the draining lymph nodes of UV-irradiated, PAFR-deficient donor mice were injected into the recipients. Because PCA 4248 also blocks serotonin receptor binding, we measured the effect that blocking both serotonin and PAFR binding has on the transfer of immune suppression. Only when both PAF and serotonin binding were blocked could we inhibit tolerance induction. These data identify a novel function for PAF and serotonin in modulating immune function, the activation of immunoregulatory B cells.
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Affiliation(s)
- Yumi Matsumura
- Department of Immunology and Center for Cancer Immunology Research, University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030; and
| | - Scott N. Byrne
- Department of Immunology and Center for Cancer Immunology Research, University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030; and
| | - Dat X. Nghiem
- Department of Immunology and Center for Cancer Immunology Research, University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030; and
- Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, TX 77225
| | - Yasuko Miyahara
- Department of Immunology and Center for Cancer Immunology Research, University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030; and
| | - Stephen E. Ullrich
- Department of Immunology and Center for Cancer Immunology Research, University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030; and
- Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, TX 77225
- Address correspondence and reprint requests to Dr. Stephen E. Ullrich, Department of Immunology-902, University of Texas, M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030. E-mail address:
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Wolf P, Nghiem DX, Walterscheid JP, Byrne S, Matsumura Y, Matsumura Y, Bucana C, Ananthaswamy HN, Ullrich SE. Platelet-activating factor is crucial in psoralen and ultraviolet A-induced immune suppression, inflammation, and apoptosis. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:795-805. [PMID: 16936256 PMCID: PMC1579250 DOI: 10.2353/ajpath.2006.060079] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Psoralen plus UVA (PUVA) is used as a very effective treatment modality for various diseases, including psoriasis and cutaneous T-cell lymphoma. PUVA-induced immune suppression and/or apoptosis are thought to be responsible for the therapeutic action. However, the molecular mechanisms by which PUVA acts are not well understood. We have previously identified platelet-activating factor (PAF), a potent phospholipid mediator, as a crucial substance triggering ultraviolet B radiation-induced immune suppression. In this study, we used PAF receptor knockout mice, a selective PAF receptor antagonist, a COX-2 inhibitor (presumably blocking downstream effects of PAF), and PAF-like molecules to test the role of PAF receptor binding in PUVA treatment. We found that activation of the PAF pathway is crucial for PUVA-induced immune suppression (as measured by suppression of delayed type hypersensitivity to Candida albicans) and that it plays a role in skin inflammation and apoptosis. Downstream of PAF, interleukin-10 was involved in PUVA-induced immune suppression but not inflammation. Better understanding of PUVA's mechanisms may offer the opportunity to dissect the therapeutic from the detrimental (ie, carcinogenic) effects and/or to develop new drugs (eg, using the PAF pathway) that act like PUVA but have fewer side effects.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Apoptosis/radiation effects
- Candida albicans/immunology
- Candidiasis/drug therapy
- Candidiasis/immunology
- Candidiasis/pathology
- Combined Modality Therapy/methods
- Female
- Ficusin/pharmacology
- Humans
- Hypersensitivity, Delayed/drug therapy
- Hypersensitivity, Delayed/immunology
- Hypersensitivity, Delayed/pathology
- Immune Tolerance/drug effects
- Immune Tolerance/immunology
- Immune Tolerance/radiation effects
- Immunosuppression Therapy/methods
- Inflammation/drug therapy
- Inflammation/immunology
- Inflammation/pathology
- Interleukin-10/immunology
- Lymphoma, T-Cell, Cutaneous/drug therapy
- Lymphoma, T-Cell, Cutaneous/immunology
- Lymphoma, T-Cell, Cutaneous/pathology
- Male
- Mice
- Mice, Knockout
- PUVA Therapy/adverse effects
- PUVA Therapy/methods
- Platelet Activating Factor/immunology
- Platelet Membrane Glycoproteins/deficiency
- Platelet Membrane Glycoproteins/immunology
- Psoriasis/drug therapy
- Psoriasis/immunology
- Psoriasis/pathology
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/immunology
- Signal Transduction/drug effects
- Signal Transduction/immunology
- Signal Transduction/radiation effects
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Affiliation(s)
- Peter Wolf
- Research Unit for Photodermatology, Department of Dermatology, Medical University Graz, Auenbrugger Platz 8, A-8036 Graz, Austria.
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Heon Seo K, Ko HM, Kim HA, Choi JH, Jun Park S, Kim KJ, Lee HK, Im SY. Platelet-activating factor induces up-regulation of antiapoptotic factors in a melanoma cell line through nuclear factor-kappaB activation. Cancer Res 2006; 66:4681-6. [PMID: 16651419 DOI: 10.1158/0008-5472.can-05-3186] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this study, we investigated the influence of platelet-activating factor (PAF) on the induction of apoptosis-regulating factors in B16F10 melanoma cells. PAF increased the expression of mRNA and the protein synthesis of antiapoptotic factors, such as Bcl-2 and Bcl-xL, but did not increase the expression of the proapoptotic factor, Bax. A selective nuclear factor-kappaB (NF-kappaB) inhibitor, parthenolide, inhibited the effects of PAF. Furthermore, PAF inhibited etoposide-induced increases in caspase-3, caspase-8, and caspase-9 activities, as well as cell death. p50/p65 heterodimer increased the mRNA expression of Bcl-2 and Bcl-xL and decreased etoposide-induced caspase activities and cell death. In an in vivo model in which Matrigel was injected s.c., PAF augmented the growth of B16F10 cells and attenuated etoposide-induced inhibition of B16F10 cells growth. These data indicate that PAF induces up-regulation of antiapoptotic factors in a NF-kappaB-dependent manner in a melanoma cell line, therefore suggesting that PAF may diminish the cytotoxic effect of chemotherapeutic agents.
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Affiliation(s)
- Kook Heon Seo
- Department of Biological Sciences, The Institute of Basic Sciences, Chonnam National University, Kwangju, Republic of Korea
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37
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Norval M. The mechanisms and consequences of ultraviolet-induced immunosuppression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2006; 92:108-18. [PMID: 16564073 DOI: 10.1016/j.pbiomolbio.2006.02.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Exposure to ultraviolet radiation (UVR) can result in immune suppression to antigens encountered within a few days of the irradiation. The process leading to the down-regulation in immune responses is complex. It is initiated by several photoreceptors located in the skin surface, namely DNA, trans-urocanic acid and membrane components. The absorption of UVR by these chromophores then leads to the release of a wide range of mediators that can affect antigen presenting cells locally or systemically. The final steps include the generation of antigen-specific T cells capable of regulating immunity. The consequences of the UV-induced changes in the skin immune system for the control of skin cancers, infectious diseases including vaccination, and autoimmune diseases are considered. Finally, the effects of active vitamin D, synthesised in the epidermis following UVR, are discussed in the context of the skin immune response.
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Affiliation(s)
- Mary Norval
- Medical Microbiology, University of Edinburgh Medical School, Teviot Place, Edinburgh EH8 9AG, Scotland, UK.
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38
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Marathe GK, Johnson C, Billings SD, Southall MD, Pei Y, Spandau D, Murphy RC, Zimmerman GA, McIntyre TM, Travers JB. Ultraviolet B Radiation Generates Platelet-activating Factor-like Phospholipids underlying Cutaneous Damage. J Biol Chem 2005; 280:35448-57. [PMID: 16115894 DOI: 10.1074/jbc.m503811200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ultraviolet B light (UVB) causes cutaneous inflammation and cell death, but the agents responsible are not defined. These studies examined the role of the platelet-activating factor (PAF) signaling system in UVB-mediated effects. Expression of the PAF receptor in the PAF receptor-negative epidermoid cell line KB augmented apoptosis in response to UVB irradiation. Overexpression of the PAF receptor in primary human keratinocytes also enhanced UVB-mediated apoptosis in vitro, and it enhanced apoptosis in an in vivo model of human keratinocytes grafted onto severe combined immune-deficient (SCID) mice. To define the mechanism by which UVB activates the PAF receptor, we used mass spectrometry to demonstrate significant amounts of the C4 PAF analogs 1-alkyl-2-(butanoyl and butenoyl)-sn-glycero-3-phosphocholine, as well as native PAF in an epidermal cell line after UVB irradiation. Supplementing the cells with the precursor phospholipid 1-hexadecyl-2-arachidonoyl-sn-glycero-3-phosphocholine (HAPC) increased the amount of C4 PAF analogs recovered after UVB exposure. We irradiated HAPC directly and found, even in the absence of a photosensitizer, fragmentation to C4-PAF receptor ligands. We conclude UVB photo-oxidizes cellular phospholipids, creating PAF analogs that stimulate the PAF receptor to induce further PAF synthesis and apoptosis. PAF signaling may participate in the cutaneous inflammation that occurs during photo-aggravated dermatoses.
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Affiliation(s)
- Gopal K Marathe
- Human Molecular Biology and Genetics Program, University of Utah, Salt Lake City 84112-5330, USA.
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39
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Kumei Y, Morita S, Nakamura H, Akiyama H, Katano H, Shimokawa H, Ohya K. Platelet-activating factor receptor signals in rat osteoblasts during spaceflight. Ann N Y Acad Sci 2005; 1030:116-20. [PMID: 15659787 DOI: 10.1196/annals.1329.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The platelet-activating factor (PAF) is a lipid mediator. The G-protein-coupled receptor of PAF (PAF-R) is activated by inflammatory and stressful conditions in numerous cell types. PAF/PAF-R is involved in apoptotic and antiapoptotic processes. We examined microgravity effects on the expression of PAF-R and second messengers in rat osteoblasts. The PAF-R signals are transmitted via arachidonic acid, phospholipase C (PLC), protein kinase C (PKC), and mitogen-activated protein kinase. Rat osteoblasts were cultured for 4 and 5 days aboard a space shuttle and solubilized on board. PAF-R gene expression in flight cultures increased to 2-6-fold higher than in ground controls. Gene expression of the G-protein alpha subunit Galphaq in flight cultures increased to 3-fold and higher than in ground controls. It is known that Galphaq stimulates the effecter PLCbeta, activating PKC. The mRNA levels of PKCdelta and PKCtheta in flight cultures were increased to 2-5-fold higher than in ground controls. The PKCalpha mRNA level in flight cultures was increased to 3-fold higher than in ground controls on the 4th day. Gene expression of catalytic and regulatory subunits of protein kinase A was suppressed in flight cultures. PKCdelta and PKCtheta are novel PKCs that can be target substrates of caspases. The PAF-R gene may act as a mechano-sensitive gene that is involved in the apoptotic and antiapoptotic processes of osteoblasts under microgravity.
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Affiliation(s)
- Yasuhiro Kumei
- Department of Hard Tissue Engineering, Graduate School of Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
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40
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Owen JS, Baker PRS, O'Flaherty JT, Thomas MJ, Samuel MP, Wooten RE, Wykle RL. Stress-induced platelet-activating factor synthesis in human neutrophils. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1733:120-9. [PMID: 15863359 DOI: 10.1016/j.bbalip.2004.12.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 11/29/2004] [Accepted: 12/28/2004] [Indexed: 11/22/2022]
Abstract
Platelet-activating factor (1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine; PAF) is a potent inflammatory mediator produced by cells in response to physical or chemical stress. The mechanisms linking cell injury to PAF synthesis are unknown. We used liquid chromatography-tandem mass spectrometry to investigate stress-induced PAF synthesis in human neutrophils. PAF synthesis induced by extracellular pH 5.4 correlated with the activation of a stress-activated kinase, p38 mitogen-activated protein kinase (MAPK), and was blocked by the p38 MAPK inhibitor SB 203580. A key enzyme of PAF synthesis, acetyl-CoA:lysoPAF acetyltransferase, which we have previously shown is a target of p38 MAPK, was also activated in an SB 203580-sensitive fashion. Another MAPK pathway, extracellular signal-regulated kinase-1/2 (ERK-1/2), was also activated. Surprisingly, the pharmacological blockade of the ERK-1/2 pathway with PD 98059 did not block, but rather enhanced, PAF accumulation. Two unexpected actions of PD 98059 may underlie this phenomenon: an augmentation of stress-induced p38 MAPK phosphorylation and an inhibition of PAF catabolism. The latter effect did not appear to be due to a direct inhibition of PAF acetylhydrolase. Finally, similar results were obtained using another form of cellular stress, hypertonic sodium chloride. These data are consistent with a model in which stress-induced PAF accumulation is regulated positively by p38 MAPK and negatively by ERK-1/2. Such a model contrasts with the PAF accumulation induced by other forms of stimulation, which we and others have found is up-regulated by both p38 MAPK and ERK-1/2.
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Affiliation(s)
- John S Owen
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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41
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Bonin F, Ryan SD, Migahed L, Mo F, Lallier J, Franks DJ, Arai H, Bennett SAL. Anti-apoptotic Actions of the Platelet-activating Factor Acetylhydrolase I α2 Catalytic Subunit. J Biol Chem 2004; 279:52425-36. [PMID: 15456758 DOI: 10.1074/jbc.m410967200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet-activating factor (PAF) is an important mediator of cell loss following diverse pathophysiological challenges, but the manner in which PAF transduces death is not clear. Both PAF receptor-dependent and -independent pathways are implicated. In this study, we show that extracellular PAF can be internalized through PAF receptor-independent mechanisms and can initiate caspase-3-dependent apoptosis when cytosolic concentrations are elevated by approximately 15 pM/cell for 60 min. Reducing cytosolic PAF to less than 10 pM/cell terminates apoptotic signaling. By pharmacological inhibition of PAF acetylhydrolase I and II (PAF-AH) activity and down-regulation of PAF-AH I catalytic subunits by RNA interference, we show that the PAF receptor-independent death pathway is regulated by PAF-AH I and, to a lesser extent, by PAF-AH II. Moreover, the anti-apoptotic actions of PAF-AH I are subunit-specific. PAF-AH I alpha1 regulates intracellular PAF concentrations under normal physiological conditions, but expression is not sufficient to reduce an acute rise in intracellular PAF levels. PAF-AH I alpha2 expression is induced when cells are deprived of serum or exposed to apoptogenic PAF concentrations limiting the duration of pathological cytosolic PAF accumulation. To block PAF receptor-independent death pathway, we screened a panel of PAF antagonists (CV-3988, CV-6209, BN 52021, and FR 49175). BN 52021 and FR 49175 accelerated PAF hydrolysis and inhibited PAF-mediated caspase 3 activation. Both antagonists act indirectly to promote PAF-AH I alpha2 homodimer activity by reducing PAF-AH I alpha1 expression. These findings identify PAF-AH I alpha2 as a potent anti-apoptotic protein and describe a new means of pharmacologically targeting PAF-AH I to inhibit PAF-mediated cell death.
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Affiliation(s)
- Fanny Bonin
- Neural Regeneration Laboratory, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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42
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Darst M, Al-Hassani M, Li T, Yi Q, Travers JM, Lewis DA, Travers JB. Augmentation of chemotherapy-induced cytokine production by expression of the platelet-activating factor receptor in a human epithelial carcinoma cell line. THE JOURNAL OF IMMUNOLOGY 2004; 172:6330-5. [PMID: 15128823 DOI: 10.4049/jimmunol.172.10.6330] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In addition to their known cytotoxic effects, chemotherapeutic agents can trigger cytokine production in tumor cells. Moreover, many chemotherapeutic agents are potent pro-oxidative stressors. Although the lipid mediator platelet-activating factor (PAF) is synthesized in response to oxidative stress, and many epidermal carcinomas express PAF receptors (PAF-R) linked to cytokine production, it is not known whether PAF is involved in chemotherapeutic agent-induced cytokine production. These studies examined the role of the PAF system in chemotherapy-mediated cytokine production using a model system created by retroviral-mediated transduction of the PAF-R-negative human epidermal carcinoma cell line KB with the human PAF-R. The presence of the PAF-R in KB cells resulted in augmentation of the production of cytokines IL-8 and TNF-alpha induced by the chemotherapeutic agents etoposide and mitomycin C. These effects were specific for the PAF-R, as expression of the G protein-coupled receptor for fMLP did not affect chemotherapeutic agent-induced cytokine production. Moreover, ablation of the native PAF-R in the epithelial cell line HaCaT using an inducible antisense PAF-R strategy inhibited etoposide-induced cytokine production. Oxidative stress and the transcription factor NF-kappaB were found to be involved in this augmentative effect, because it was mimicked by the oxidant tert-butyl-hydroperoxide, which was blocked both by antioxidants and by inhibition of the NFkappaB pathway using a super-repressor IkappaBM mutant. These studies provide evidence for a novel pathway by which the epidermal PAF-R can augment chemotherapy-induced cytokine production through an NF-kappaB-dependent process.
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MESH Headings
- Adjuvants, Immunologic/biosynthesis
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/physiology
- Antineoplastic Agents/antagonists & inhibitors
- Antineoplastic Agents/pharmacology
- Antioxidants/pharmacology
- Carcinoma, Squamous Cell/drug therapy
- Carcinoma, Squamous Cell/immunology
- Carcinoma, Squamous Cell/metabolism
- Chromans/pharmacology
- Cytokines/antagonists & inhibitors
- Cytokines/biosynthesis
- Etoposide/antagonists & inhibitors
- Etoposide/pharmacology
- Humans
- Interleukin-8/antagonists & inhibitors
- Interleukin-8/biosynthesis
- Interleukin-8/genetics
- KB Cells
- Mitomycin/pharmacology
- NF-kappa B/physiology
- Oxidative Stress/drug effects
- Phospholipid Ethers/pharmacology
- Platelet Membrane Glycoproteins/biosynthesis
- Platelet Membrane Glycoproteins/deficiency
- Platelet Membrane Glycoproteins/genetics
- Platelet Membrane Glycoproteins/physiology
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/biosynthesis
- Receptors, G-Protein-Coupled/biosynthesis
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/physiology
- Signal Transduction/drug effects
- Signal Transduction/immunology
- Tetradecanoylphorbol Acetate/pharmacology
- Transduction, Genetic
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Affiliation(s)
- Marc Darst
- Department of Dermatology, H. B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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43
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Stafforini DM, McIntyre TM, Zimmerman GA, Prescott SM. Platelet-activating factor, a pleiotrophic mediator of physiological and pathological processes. Crit Rev Clin Lab Sci 2004; 40:643-72. [PMID: 14708958 DOI: 10.1080/714037693] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Platelet-activating factor (PAF) is a potent proinflammatory phospholipid with diverse pathological and physiological effects. This bioactive phospholipid mediates processes as diverse as wound healing, physiological inflammation, apoptosis, angiogenesis, reproduction and long-term potentiation. Recent progress has demonstrated the participation of MAP kinase signaling pathways as modulators of the two critical enzymes, phospholipase A2 and acetyltransferase, involved in the remodeling pathway of PAF biosynthesis. The unregulated production of structural analogs of PAF by non-specific oxidative reactions has expanded this superfamily of signaling molecules to include "PAF-like" lipids whose mode of action is identical to that of authentic PAF. The action of members of this family is mediated by the PAF receptor, a G protein-coupled membrane-spanning molecule that can engage multiple signaling pathways in various cell types. Inappropriate activation of this signaling pathway is associated with many diseases in which inflammation is thought to be one of the underlying features. Inactivation of all members of the PAF superfamily occurs by a unique class of enzymes, the PAF acetylhydrolases, that have been characterized at the molecular level and that terminate signals initiated by both regulated and unregulated PAF production.
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Affiliation(s)
- Diana M Stafforini
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112-5550, USA.
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Heck DE, Gerecke DR, Vetrano AM, Laskin JD. Solar ultraviolet radiation as a trigger of cell signal transduction. Toxicol Appl Pharmacol 2004; 195:288-97. [PMID: 15020191 DOI: 10.1016/j.taap.2003.09.028] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Accepted: 09/12/2003] [Indexed: 10/26/2022]
Abstract
Ultraviolet light radiation in sunlight is known to cause major alterations in growth and differentiation patterns of exposed human tissues. The specific effects depend on the wavelengths and doses of the light, and the nature of the exposed tissue. Both growth inhibition and proliferation are observed, as well as inflammation and immune suppression. Whereas in the clinical setting, these responses may be beneficial, for example, in the treatment of psoriasis and atopic dermatitis, as an environmental toxicant, ultraviolet light can induce significant tissue damage. Thus, in the eye, ultraviolet light causes cataracts, while in the skin, it induces premature aging and the development of cancer. Although ultraviolet light can damage many tissue components including membrane phospholipids, proteins, and nucleic acids, it is now recognized that many of its cellular effects are due to alterations in growth factor- and cytokine-mediated signal transduction pathways leading to aberrant gene expression. It is generally thought that reactive oxygen intermediates are mediators of some of the damage induced by ultraviolet light. Generated when ultraviolet light is absorbed by endogenous photosensitizers in the presence of molecular oxygen, reactive oxygen intermediates and their metabolites induce damage by reacting with cellular electrophiles, some of which can directly initiate cell signaling processes. In an additional layer of complexity, ultraviolet light-damaged nucleic acids initiate signaling during the activation of repair processes. Thus, mechanisms by which solar ultraviolet radiation triggers cell signal transduction are multifactorial. The present review summarizes some of the mechanisms by which ultraviolet light alters signaling pathways as well as the genes important in the beneficial and toxic effects of ultraviolet light.
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Affiliation(s)
- Diane E Heck
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, NJ 08854, USA
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Lu J, Caplan MS, Saraf AP, Li D, Adler L, Liu X, Jilling T. Platelet-activating factor-induced apoptosis is blocked by Bcl-2 in rat intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2004; 286:G340-50. [PMID: 14512286 DOI: 10.1152/ajpgi.00182.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Plateletactivating factor (PAF) is a key mediator in pathogenesis of inflammatory bowel diseases (IBDs) but mechanisms of PAF-induced mucosal injury are poorly understood. To determine whether apoptosis and the Bcl-2-family of apoptosis regulatory gene products play a role in PAF-induced mucosal injury, we stably and conditionally overexpressed bcl-2 in rat small intestinal epithelial cells-6 under the control of a lactose-inducible promoter. Western blot analysis and immuno-histochemistry were used to verify inducible Bcl-2 and to analyze Bcl-2 and a proapoptotic member of the Bcl-2 family, Bax, subcellular distribution. DNA fragmentation was quantified by ELISA, caspase activity was measured by using fluorogenic peptide substrates, and mitochondrial membrane potential was assayed by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) and fluorescence digital imaging. Bcl-2 expression was highly inducible by lactose analog isopropyl-beta-(d)-thiogalactoside (IPTG) and was localized predominantly to mitochondria. In the absence of bcl-2 overexpression and after treatment with PAF, Bax translocated to mitochondria, and mitochondrial membrane potential collapsed within 1 h, followed by caspase-3 activation, which peaked at 6 h with an ensuing DNA fragmentation maximizing at 18 h. After IPTG-induction of bcl-2 expression, PAF failed to induce DNA fragmentation, caspase-3 activation, Bax translocation, or a collapse of mitochondrial membrane potential. These data are the first to show that PAF can activate apoptotic machinery in enterocytes via a mechanism involving Bax translocation and collapse of mitochondrial membrane potential and that both of these events are under control by bcl-2 expression levels. A better understanding of the role of PAF and Bcl-2 family of apoptosis regulators in epithelial cell death might aid design of better therapeutic or preventive strategies for IBDs.
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Affiliation(s)
- Jing Lu
- Department of Pediatrics, Northwestern University, Feinberg School of Medicine, 2650 Ridge Ave., Evanston, IL 60201, USA
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Li T, Southall MD, Yi Q, Pei Y, Lewis D, Al-Hassani M, Spandau D, Travers JB. The epidermal platelet-activating factor receptor augments chemotherapy-induced apoptosis in human carcinoma cell lines. J Biol Chem 2003; 278:16614-21. [PMID: 12601006 DOI: 10.1074/jbc.m211287200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most chemotherapeutic agents exert their cytotoxic effects in part through the induction of apoptosis. In addition, many chemotherapeutic agents are potent pro-oxidative stressors. Although the lipid mediator platelet-activating factor (PAF) is synthesized in response to oxidative stress, and many epidermal carcinomas express PAF receptors, it is not known whether PAF is involved in chemotherapeutic agent-induced apoptosis. These studies examined the role of the PAF system in chemotherapy-mediated cytotoxicity using model systems created by retroviral mediated transduction of the PAF receptor-negative human epidermal carcinoma cell line KB with the human PAF receptor (PAF-R) and ablation of the endogenous PAF-R in the carcinoma cell line HaCaT with a retroviral mediated inducible antisense PAF-R vector. The presence of the PAF-R in these models resulted in an augmentation of apoptosis induced by chemotherapeutic agents etoposide and mitomycin C but not by tumor necrosis factor-related apoptosis-inducing ligand or by C(2) ceramide. Oxidative stress and the transcription factor nuclear factor kappaB (NF-kappaB) are found to be involved in this augmentative effect because it was blocked by antioxidants and inhibition of the NF-kappaB pathway using a super-repressor form of inhibitor B. These studies provide evidence for a novel pathway whereby the epidermal PAF-R can augment chemotherapy-induced apoptotic effects through an NF-kappaB-dependent process.
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Affiliation(s)
- Tao Li
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Lewis DA, Zweig B, Hurwitz SA, Spandau DF. Inhibition of erbB receptor family members protects HaCaT keratinocytes from ultraviolet-B-induced apoptosis. J Invest Dermatol 2003; 120:483-8. [PMID: 12603863 DOI: 10.1046/j.1523-1747.2003.12060.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the human epidermis, the cells most at risk for the development of cancer due to sunlight exposure are the keratinocytes. In animal models, ultraviolet-B is a complete carcinogen, capable of inducing and promoting the development of malignant cells. A key element of ultraviolet-B-induced carcinogenesis is the ability of ultraviolet-B to induce the expression of a number of cellular proteins and activate growth factor receptor tyrosine kinases, including the erbB receptor family. Keratinocytes express the erbB1 (also called EGF-R, HER1), the erbB2 (also known as neu or HER2), and the erbB3 (HER3) subtypes. In general, activation of the erbB receptor family leads to a cellular proliferative response. In certain instances, however, activation of an erbB receptor can induce differentiation, cell cycle arrest, and even apoptosis. The inhibition of tyrosine kinase activity in rodent models and human skin has been shown to inhibit some ultraviolet-B response pathways. We have shown that the inhibition of erbB receptors, by both pharmaceutical and immunologic means, will inhibit ultraviolet-B-induced apoptosis in the HaCaT human keratinocyte cell line. This inhibition was specific for the erbB receptor family and specific for ultraviolet-B-induced apoptosis. These results suggest that, in certain instances, ultraviolet-B-induced apoptotic signaling requires erbB family receptor activity.
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Affiliation(s)
- Davina A Lewis
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A
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Sakamoto H, Tosaki T, Nakagawa Y. Overexpression of phospholipid hydroperoxide glutathione peroxidase modulates acetyl-CoA, 1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase activity. J Biol Chem 2002; 277:50431-8. [PMID: 12397078 DOI: 10.1074/jbc.m204190200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The synthesis of platelet-activating factor (PAF) by -stimulated RBL-2H3 cells was significantly suppressed by overexpression of phospholipid hydroperoxide glutathione peroxidase (PHGPx). When the cells overexpressing PHGPx (L9 cells) were pretreated with diethyl maleate, which reduces PHGPx activity, PAF synthesis upon stimulation rose to levels seen in mock-transfected cells (S1 cells). Hydroperoxide levels, which are reduced in L9 cells, are involved in regulating PAF synthesis, because the addition of hydroperoxyeicosatetraenoic acid increased PAF production in -stimulated L9 cells to control cell levels. The activity of acetyl-CoA:1-O-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase, which is involved in the last step of PAF synthesis, is also reduced in L9 cells. p38 kinase inhibitors block acetyltransferase activity in normal -stimulated cells, suggesting that p38 kinase is involved in regulating acetyltransferase activity. Recombinant active p38 kinase activates acetyltransferase, whereas alkaline phosphatase reverses this, suggesting p38 kinase directly phosphorylates acetyltransferase. p38 kinase phosphorylation is blocked in L9 cells, indicating that high hydroperoxide levels are needed for the activation of p38 kinase. Thus, intracellular hydroperoxide levels participate in regulating p38 kinase phosphorylation, which in turn controls the activation of acetyltransferase and thus the synthesis of PAF. These observations suggest that PHGPx is an important component of the mechanisms regulating inflammation.
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Affiliation(s)
- Hikaru Sakamoto
- School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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Marques M, Pei Y, Southall MD, Johnston JM, Arai H, Aoki J, Inoue T, Seltmann H, Zouboulis CC, Travers JB. Identification of platelet-activating factor acetylhydrolase II in human skin. J Invest Dermatol 2002; 119:913-9. [PMID: 12406338 DOI: 10.1046/j.1523-1747.2002.01859.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Platelet-activating factor acetylhydrolases are a family of specialized phospholipase A2 enzymes. They serve an anti-inflammatory function by converting the proinflammatory autocoid, PAF, into biologically inactive lyso-PAF, by the removal of the sn-2 acetyl group of this glycerophospholipid. Similarly, platelet-activating factor acetylhydrolases can also degrade oxidatively modified sn-2 polyunsaturated-fatty-acid-containing phospholipids, which are toxic to cells. Platelet-activating factor acetylhydrolase II is a recently cloned member of this family of specialized phospholipases. Consistent with a potential role of this intracellular enzyme in protecting membrane phospholipids against oxidative stress, platelet-activating factor acetylhydrolase II has been shown to translocate from cytosol to membranes in response to pro-oxidative stressors, and overexpression of this enzyme decreases the cytotoxic effects of these agents. The objective of this study was to assess whether platelet-activating factor acetylhydrolase II is involved in protecting skin against oxidative stress. Platelet-activating factor acetylhydrolase II protein was demonstrated in human skin by immunohistochemistry, with the highest levels of the enzyme found in sebaceous glands and lesser amounts in epidermal keratinocytes. Treatment of epidermal cells with t-butylhydroperoxide or ultraviolet B radiation resulted in platelet-activating factor acetylhydrolase II translocation from cytosol to membranes. To assess the role of this enzyme in epidermal function, a recombinant retroviral strategy was used to overexpress platelet-activating factor acetylhydrolase II in the human keratinocyte-derived cell line HaCaT. Overexpression of platelet-activating factor acetylhydrolase II protected HaCaT cells against apop tosis induced by oxidative stressors t-butylhydroperoxide and ultraviolet B radiation. Similar levels of apoptosis, however, were seen in both control and platelet-activating-factor-acetylhydrolase-II-over expressing HaCaT cells in response to C2 ceramide. These studies demonstrate the presence of platelet-activating factor acetylhydrolase II in a restricted pattern in human skin, and provide evidence that this specialized phospholipase is involved in protecting this organ against oxidative stress through the degradation of oxidatively modified bioactive phospholipids.
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Affiliation(s)
- Mariangela Marques
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202, U.S.A
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Marques SA, Dy LC, Southall MD, Yi Q, Smietana E, Kapur R, Marques M, Travers JB, Spandau DF. The platelet-activating factor receptor activates the extracellular signal-regulated kinase mitogen-activated protein kinase and induces proliferation of epidermal cells through an epidermal growth factor-receptor-dependent pathway. J Pharmacol Exp Ther 2002; 300:1026-35. [PMID: 11861812 DOI: 10.1124/jpet.300.3.1026] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Platelet-activating factor (PAF) is a lipid mediator that has been implicated in a variety of keratinocyte functions. Keratinocytes express the specific receptor for PAF (PAF-R), a seven-transmembrane G-protein-coupled receptor. Although PAF-R-dependent stimulation of numerous signal transduction pathways has been shown in a variety of cell types, to date there has been no analysis of PAF-R signal transduction in human epidermal cells. There is also contradictory evidence that PAF acts as either a suppressor or activator of keratinocyte proliferation. Using a model system created by retroviral-mediated transduction of the PAF-R into the PAF-R-negative epidermal cell line KB, we now demonstrate that the activation of the epidermal PAF-R results in the activation of both the extracellular signal-regulated kinase (ERK) and p38, but not the jun N-terminal kinase mitogen-activated protein (MAP) kinase pathways. Additionally, we show that the activation of the PAF-R stimulates the replication of epidermal cells. The activation of the ERK signal transduction pathway, as well as the PAF-dependent increase in cell proliferation, was dependent on the transactivation of the epidermal growth factor receptor (EGF-R). PAF-R-induced transactivation of the EGF-R was blocked by pharmacologic inhibitors of matrix metalloproteinases, of heparin-binding epidermal growth factor (HB-EGF), and specific inhibitors of the EGF-R tyrosine kinase. Activation of p38 MAP kinase by the PAF-R was not dependent on EGF-R activation and represents a distinct pathway of PAF-R-mediated signal transduction. In summary, these studies provide a mechanism whereby the PAF-R can exert proliferative effects through the activation of the EGF-R.
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Affiliation(s)
- Silvio A Marques
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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