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Increased Expression of Indoleamine 2,3-Dioxygenase (IDO) in Vogt-Koyanagi-Harada (VKH) Disease May Lead to a Shift of T Cell Responses Toward a Treg Population. Inflammation 2021; 43:1780-1788. [PMID: 32435912 DOI: 10.1007/s10753-020-01252-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Previous studies have pointed out that indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme initiating tryptophan metabolism, plays a role in the regulation of the immune system. This project was designed to investigate the potential role of IDO in monocyte-derived dendritic cells (moDCs) obtained from active Vogt-Koyanagi-Harada (VKH) disease patients. In this study, we found that the IDO mRNA expression and enzyme activity were increased in active VKH patients as compared with healthy controls and patients in remission. To investigate the role of IDO in immune regulation, an effective inhibitor 1-methyl-L-tryptophan (1-MT) was used to suppress its activity in DCs. The results showed that inhibition of IDO with 1-MT significantly decreased the expression of DC marker CD86. IDO inhibition did not affect the cytokine production of IL-6, IL-1β, TNF-α, IL-10, and TGF-β in DCs. Downregulation of IDO in DCs also led to the reduction of regulatory T (Treg) cells and an increased CD4+ T cell proliferation. Treatment with 1-MT did not affect the phosphorylation of the MAPK pathway in DCs. In general, our study suggests that IDO may play an important role in the pathogenesis of VKH disease by regulating DC and CD4+ T cell function. Tryptophan deficiency and kynurenine accumulation may account for the complicated effects of IDO. Further research is needed to study the precise tryptophan metabolites that may limit immune responses in VKH disease.
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Rochet E, Argy N, Greigert V, Brunet J, Sabou M, Marcellin L, de-la-Torre A, Sauer A, Candolfi E, Pfaff AW. Type I ROP16 regulates retinal inflammatory responses during ocular toxoplasmosis. PLoS One 2019; 14:e0214310. [PMID: 30901349 PMCID: PMC6430381 DOI: 10.1371/journal.pone.0214310] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/11/2019] [Indexed: 11/18/2022] Open
Abstract
Ocular toxoplasmosis (OT), mostly retinochorioditis, is a major feature of infection with the protozoan parasite Toxoplasma gondii. The pathophysiology of this infection is still largely elusive; especially mouse models are not yet well developed. In contrast, numerous in vitro studies showed the highly Toxoplasma strain dependent nature of the host-parasite interactions. Some distinct polymorphic virulence factors were characterized, notably the rhoptry protein ROP16. Here, we studied the strain-dependent pathophysiology in our OT mouse model. Besides of two wild type strains of the canonical I (RH, virulent) and II (PRU, avirulent) types, we used genetically engineered parasites, RHΔROP16 and PRU ROP16-I, expressing the type I allele of this virulence factor. We analyzed retinal integrity, parasite proliferation and retinal expression of cytokines. PRU parasites behaved much more virulently in the presence of a type I ROP16. In contrast, knockout of ROP16 in the RH strain led to a decrease of intraocular proliferation, but no difference in retinal pathology. Cytokine quantification in aqueous humor showed strong production of Th1 and inflammatory markers following infection with the two strains containing the ROP16-I allele. In strong contrast, immunofluorescence images showed that actual expression of most cytokines in retinal cells is rapidly suppressed by type I strain infection, with or without the involvement of its homologous ROP16 allele. This demonstrates the particular immune privileged situation of the retina, which is also revealed by the fact that parasite proliferation is nearly exclusively observed outside the retina. In summary, we further developed a promising OT mouse model and demonstrated the specific pathology in retinal tissues.
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Affiliation(s)
- Elise Rochet
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
| | - Nicolas Argy
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
| | - Valentin Greigert
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
| | - Julie Brunet
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
- Service de Parasitologie et Mycologie Médicale, Hôpitaux Universitaires de Strasbourg, Centre National de Référence de la Toxoplasmose, Pôle Sérologie, Strasbourg, France
| | - Marcela Sabou
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
- Service de Parasitologie et Mycologie Médicale, Hôpitaux Universitaires de Strasbourg, Centre National de Référence de la Toxoplasmose, Pôle Sérologie, Strasbourg, France
| | - Luc Marcellin
- Service de Pathologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Alejandra de-la-Torre
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
- Grupo NeURos, Unidad de Inmunología, Universidad del Rosario, Escuela de Medicina y Ciencias de la Salud, Bogotá, Colombia
| | - Arnaud Sauer
- Service d’Ophtalmologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Ermanno Candolfi
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
- Service de Parasitologie et Mycologie Médicale, Hôpitaux Universitaires de Strasbourg, Centre National de Référence de la Toxoplasmose, Pôle Sérologie, Strasbourg, France
| | - Alexander W. Pfaff
- Institut de Parasitologie et Pathologie Tropicale, EA, Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
- Service de Parasitologie et Mycologie Médicale, Hôpitaux Universitaires de Strasbourg, Centre National de Référence de la Toxoplasmose, Pôle Sérologie, Strasbourg, France
- * E-mail:
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hCMV-Mediated Immune Escape Mechanisms Favor Pathogen Growth and Disturb the Immune Privilege of the Eye. Int J Mol Sci 2019; 20:ijms20040858. [PMID: 30781494 PMCID: PMC6413209 DOI: 10.3390/ijms20040858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/05/2019] [Accepted: 02/12/2019] [Indexed: 12/15/2022] Open
Abstract
Human retinal pigment epithelial (hRPE) cells are important for the establishment and maintenance of the immune privilege of the eye. They function as target cells for human cytomegalovirus (hCMV), but are able to restrict viral replication. hCMV causes opportunistic posterior uveitis such as retinitis and chorioretinitis. Both mainly occur in severely immunocompromised patients and rarely manifest in immunocompetent individuals. In this study, hRPE cells were infected with hCMV in vitro and activated with proinflammatory cytokines. The enzymatic activities of indoleamine 2,3-dioxygenase-1 (IDO1) and inducible nitric oxide synthase (iNOS) were determined. The antimicrobial capacity of both molecules was analyzed in co-infection experiments using Staphylococcus aureus (S. aureus) and Toxoplasmagondii (T. gondii), causing uveitis in patients. We show that an hCMV infection of hRPE cells blocks IDO1 and iNOS mediated antimicrobial defense mechanisms necessary for the control of S. aureus and T. gondii. hCMV also inhibits immune suppressive effector mechanisms in hRPE. The interferon gamma-induced IDO1 dependent immune regulation was severely blocked, as detected by the loss of T cell inhibition. We conclude that an active hCMV infection in the eye might favor the replication of pathogens causing co-infections in immunosuppressed individuals. An hCMV caused blockade of IDO1 might weaken the eye’s immune privilege and favor the development of post-infectious autoimmune uveitis.
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Zhao Z, Liang Y, Liu Y, Xu P, Flamme-Wiese MJ, Sun D, Sun J, Mullins RF, Chen Y, Cai J. Choroidal γδ T cells in protection against retinal pigment epithelium and retinal injury. FASEB J 2017; 31:4903-4916. [PMID: 28729290 DOI: 10.1096/fj.201700533r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 07/05/2017] [Indexed: 12/17/2022]
Abstract
γδ T cells located near the epithelial barrier are integral components of local inflammatory and innate immune responses. We have previously reported the presence of choroidal γδ T cells in a model of chronic degeneration of the retinal pigment epithelium (RPE). The goals of the current study were to further define the functions of choroidal γδ T cells and to explore the underlying mechanisms of their action. Our data demonstrate that choroidal γδ T cells are activated by RPE injury in response to NaIO3 treatment, and that they express genes that encode immunosuppressive cytokines, such as IL-4 and IL-10. γδ-T-cell-deficient mice developed profound RPE and retinal damage at doses that caused minimal effects in wild-type mice, and adoptive transfer of γδ T cells prevented sensitization. Intravitreal injection of IL-4 and IL-10 ameliorated RPE toxicity that was induced by NaIO3Ex vivo coculture of γδ T cells with RPE explants activated the production of anti-inflammatory cytokines via an aryl hydrocarbon receptor (AhR)-dependent mechanism. AhR deficiency abolished the protective effects of γδ T cells after adoptive transfer. Collectively, these findings define important roles for choroid γδ T cells in maintaining tissue homeostasis in the outer retina.-Zhao, Z., Liang, Y., Liu, Y., Xu, P., Flamme-Wiese, M. J., Sun, D., Sun, J., Mullins, R. F., Chen, Y., Cai, J. Choroidal γδ T cells in protection against retinal pigment epithelium and retinal injury.
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Affiliation(s)
- Zhenyang Zhao
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Yin Liu
- Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Pei Xu
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Miles J Flamme-Wiese
- Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, USA
| | - Deming Sun
- Doheny Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - Jiaren Sun
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Robert F Mullins
- Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, USA
| | - Yan Chen
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Jiyang Cai
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA;
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YAN FENG, HE JIN, TANG LI, KONG YI, SHI YUHUA, CHEN SUIHUA, HUANG ZHENPING. Transforming growth factor-β2 increases the capacity of retinal pigment epithelial cells to induce the generation of regulatory T cells. Mol Med Rep 2015; 13:1367-72. [DOI: 10.3892/mmr.2015.4666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 10/26/2015] [Indexed: 11/05/2022] Open
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