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Zhou L, Ho BM, Chan HYE, Tong Y, Du L, He JN, Ng DSC, Tham CC, Pang CP, Chu WK. Emerging Roles of cGAS-STING Signaling in Mediating Ocular Inflammation. J Innate Immun 2023; 15:739-750. [PMID: 37778330 PMCID: PMC10616671 DOI: 10.1159/000533897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/28/2023] [Indexed: 10/03/2023] Open
Abstract
Cyclic GMP-AMP (cGAMP) synthase (cGAS), a sensor of cytosolic DNA, recognizes cytoplasmic nucleic acids to activate the innate immune responses via generation of the second messenger cGAMP and subsequent activation of the stimulator of interferon genes (STINGs). The cGAS-STING signaling has multiple immunologic and physiological functions in all human vital organs. It mediates protective innate immune defense against DNA-containing pathogen infection, confers intrinsic antitumor immunity via detecting tumor-derived DNA, and gives rise to autoimmune and inflammatory diseases upon aberrant activation by cytosolic leakage of self-genomic and mitochondrial DNA. Disruptions in these functions are associated with the pathophysiology of various immunologic and neurodegenerative diseases. Recent evidence indicates important roles of the cGAS-STING signaling in mediating inflammatory responses in ocular inflammatory and inflammation-associated diseases, such as keratitis, diabetic retinopathy, age-related macular degeneration, and uveitis. In this review, we summarize the recently emerging evidence of cGAS-STING signaling in mediating ocular inflammatory responses and affecting pathogenesis of these complex eye diseases. We attempt to provide insightful perspectives on future directions of investigating cGAS-STING signaling in ocular inflammation. Understanding how cGAS-STING signaling is modulated to mediate ocular inflammatory responses would allow future development of novel therapeutic strategies to treat ocular inflammation and autoimmunity.
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Affiliation(s)
- Linbin Zhou
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Bo Man Ho
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Hoi Ying Emily Chan
- Medicine Programme Global Physician-Leadership Stream, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Yan Tong
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Lin Du
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Jing Na He
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Danny Siu-Chun Ng
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Clement C. Tham
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR
- Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
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Mölzer C, Heissigerova J, Wilson HM, Kuffova L, Forrester JV. Immune Privilege: The Microbiome and Uveitis. Front Immunol 2021; 11:608377. [PMID: 33569055 PMCID: PMC7868421 DOI: 10.3389/fimmu.2020.608377] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/04/2020] [Indexed: 02/03/2023] Open
Abstract
Immune privilege (IP), a term introduced to explain the unpredicted acceptance of allogeneic grafts by the eye and the brain, is considered a unique property of these tissues. However, immune responses are modified by the tissue in which they occur, most of which possess IP to some degree. The eye therefore displays a spectrum of IP because it comprises several tissues. IP as originally conceived can only apply to the retina as it contains few tissue-resident bone-marrow derived myeloid cells and is immunologically shielded by a sophisticated barrier – an inner vascular and an outer epithelial barrier at the retinal pigment epithelium. The vascular barrier comprises the vascular endothelium and the glia limitans. Immune cells do not cross the blood-retinal barrier (BRB) despite two-way transport of interstitial fluid, governed by tissue oncotic pressure. The BRB, and the blood-brain barrier (BBB) mature in the neonatal period under signals from the expanding microbiome and by 18 months are fully established. However, the adult eye is susceptible to intraocular inflammation (uveitis; frequency ~200/100,000 population). Uveitis involving the retinal parenchyma (posterior uveitis, PU) breaches IP, while IP is essentially irrelevant in inflammation involving the ocular chambers, uveal tract and ocular coats (anterior/intermediate uveitis/sclerouveitis, AU). Infections cause ~50% cases of AU and PU but infection may also underlie the pathogenesis of immune-mediated “non-infectious” uveitis. Dysbiosis accompanies the commonest form, HLA-B27–associated AU, while latent infections underlie BRB breakdown in PU. This review considers the pathogenesis of uveitis in the context of IP, infection, environment, and the microbiome.
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Affiliation(s)
- Christine Mölzer
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Jarmila Heissigerova
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
| | - Heather M Wilson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Lucia Kuffova
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Eye Clinic, Aberdeen Royal Infirmary, Aberdeen, United Kingdom
| | - John V Forrester
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
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Yoon CH, Choi HJ, Kim MK. Corneal xenotransplantation: Where are we standing? Prog Retin Eye Res 2021; 80:100876. [PMID: 32755676 PMCID: PMC7396149 DOI: 10.1016/j.preteyeres.2020.100876] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/23/2020] [Accepted: 06/04/2020] [Indexed: 02/08/2023]
Abstract
The search for alternatives to allotransplants is driven by the shortage of corneal donors and is demanding because of the limitations of the alternatives. Indeed, current progress in genetically engineered (GE) pigs, the introduction of gene-editing technology by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9, and advanced immunosuppressants have made xenotransplantation a possible option for a human trial. Porcine corneal xenotransplantation is considered applicable because the eye is regarded as an immune-privileged site. Furthermore, recent non-human primate studies have shown long-term survival of porcine xenotransplants in keratoplasty. Herein, corneal immune privilege is briefly introduced, and xenogeneic reactions are compared with allogeneic reactions in corneal transplantation. This review describes the current knowledge on special issues of xenotransplantation, xenogeneic rejection mechanisms, current immunosuppressive regimens of corneal xenotransplantation, preclinical efficacy and safety data of corneal xenotransplantation, and updates of the regulatory framework to conduct a clinical trial on corneal xenotransplantation. We also discuss barriers that might prevent xenotransplantation from becoming common practice, such as ethical dilemmas, public concerns on xenotransplantation, and the possible risk of xenozoonosis. Given that the legal definition of decellularized porcine cornea (DPC) lies somewhere between a medical device and a xenotransplant, the preclinical efficacy and clinical trial data using DPC are included. The review finally provides perspectives on the current standpoint of corneal xenotransplantation in the fields of regenerative medicine.
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Affiliation(s)
- Chang Ho Yoon
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea; Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea
| | - Hyuk Jin Choi
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea; Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea; Department of Ophthalmology, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Republic of Korea
| | - Mee Kum Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea; Laboratory of Ocular Regenerative Medicine and Immunology, Seoul Artificial Eye Center, Seoul National University Hospital Biomedical Research Institute, Seoul, Republic of Korea.
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4
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I-a lowCD11b high DC Regulates the Immune Response in the Eyes of Experimental Autoimmune Uveitis. Mediators Inflamm 2020; 2020:6947482. [PMID: 32256194 PMCID: PMC7085850 DOI: 10.1155/2020/6947482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 12/30/2019] [Indexed: 12/23/2022] Open
Abstract
Regulatory dendritic cells (DCreg) have been reported to be a negative regulator in the immune response. These cells are widely distributed in the liver, spleen, and lung. However, the status and function of DCreg in the eyes and disease are still not very clear. Herein, we found that the number of I-alowCD11bhigh DC increased in the eye and spleen at the recovery stage of experimental autoimmune uveitis (EAU), which is a mouse model for autoimmune uveitis. These cells expressed lower levels of CD80, CD86, and CD54 than the mature DCs and expressed interleukin 10 (IL-10), indoleamine 2,3-dioxygenase (IDO), and transforming growth factor beta (TGF-β) as well. Moreover, these DCreg can regulate the development of EAU by promoting CD4+CD25+Foxp3+ regulatory T cells. The increased interferon-gamma (IFN-γ) in the aqueous humor of EAU participates in inducing DCreg to alleviate the symptom of EAU. Furthermore, DCreg was found to exist in the eyes of normal mice. Aqueous humor, containing a certain concentration of IL-10, TGF-β, prostaglandin E2 (PGE2), IDO, and nitric oxide (NO), induced the tolerance of DCreg in normal eyes. It can be concluded that DCreg exists in the eyes and plays a protective role in inflamed eyes. These DCreg induced by IFN-γ might be used as a strategy to develop therapy for EAU management.
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Gu R, Ding X, Tang W, Lei B, Jiang C, Xu G. A Synthesized Glucocorticoid- Induced Leucine Zipper Peptide Inhibits Retinal Müller Cell Gliosis. Front Pharmacol 2018; 9:331. [PMID: 29681857 PMCID: PMC5897418 DOI: 10.3389/fphar.2018.00331] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/21/2018] [Indexed: 12/23/2022] Open
Abstract
Purpose: The anti-inflammatory activities of protein glucocorticoid-induced leucine zipper (GILZ) have been demonstrated in vivo and in vitro. Here, we examined the potential effect of a synthetic peptide derived from the leucine zipper motif and proline-rich region of GILZ on suppressing inflammatory responses in primary cultured rat Müller cells. Methods: Peptides were selected from amino acids 98–134 of the GILZ protein (GILZ-p). Solid-phase peptide synthesis was used to generate the cell-penetrating peptide TAT, which was bound to the amino terminus of GILZ-p. Primary cultured retinal Müller cells were stimulated with lipopolysaccharide (LPS) alone or in combination with different concentrations of GILZ-p, and the interaction of GILZ-p with nuclear factor (NF)-κB p65 in Müller cells was investigated by western blotting, immunoprecipitation, and immunofluorescence. The expression of the Müller cell gliosis marker glial fibrillary acidic protein (GFAP), functional protein aquaporin (AQP)-4, and the inflammatory cytokines interleukin (IL)-1β, tumor necrosis factor (TNF) α, intercellular adhesion molecule (ICAM)-1, and monocyte chemoattractant protein (MCP)-1 was measured by Western Blotting. The concentration of those cytokines in culture medium was measured by using Enzyme-Linked Immunosorbent Assay. Results: The synthesized GILZ-p, which was water-soluble, entered cells and bound with NF-κB p65, inhibiting p65 nuclear translocation. GILZ-p inhibited the LPS-induced expression of GFAP, IL-1β, TNFα, ICAM-1, and MCP-1 in Müller cells and prevented the LPS-induced downregulation of AQP4. Conclusions: These results indicate that GILZ-p interacted with NF-κB p65 and suppressed p65 nuclear translocation, thereby inhibiting inflammatory cytokine release and Müller cell gliosis.
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Affiliation(s)
- Ruiping Gu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Xinyi Ding
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Wenyi Tang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Boya Lei
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Chen Jiang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
| | - Gezhi Xu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,Key Laboratory of Myopia of State Health Ministry, Fudan University, Shanghai, China
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6
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Ho P, Chen YY. Synthetic Biology in Immunotherapy and Stem Cell Therapy Engineering. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Patrick Ho
- University of California; Department of Chemical and Biomolecular Engineering; 420 Westwood Plaza, Boelter Hall 5532, Los Angeles CA 90095 USA
| | - Yvonne Y. Chen
- University of California; Department of Chemical and Biomolecular Engineering; 420 Westwood Plaza, Boelter Hall 5532, Los Angeles CA 90095 USA
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Eslani M, Putra I, Shen X, Hamouie J, Tadepalli A, Anwar KN, Kink JA, Ghassemi S, Agnihotri G, Reshetylo S, Mashaghi A, Dana R, Hematti P, Djalilian AR. Cornea-Derived Mesenchymal Stromal Cells Therapeutically Modulate Macrophage Immunophenotype and Angiogenic Function. Stem Cells 2018; 36:775-784. [PMID: 29341332 DOI: 10.1002/stem.2781] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 12/12/2022]
Abstract
Macrophages are crucial drivers of inflammatory corneal neovascularization and thus are potential targets for immunomodulatory therapies. We hypothesized that therapeutic use of cornea-derived mesenchymal stromal cells (cMSCs) may alter the function of macrophages. We found that cMSCs can modulate the phenotype and angiogenic function of macrophages. In vitro, cMSCs induce apoptosis of macrophages while preferentially promoting a distinct CD14hi CD16hi CD163hi CD206hi immunophenotype that has significantly reduced angiogenic effects based on in vitro angiogenesis assays. In vivo, application of cMSCs to murine corneas after injury leads to reduced macrophage infiltration and higher expression of CD206 in macrophages. Macrophages cocultured ("educated") by cMSCs express significantly higher levels of anti-angiogenic and anti-inflammatory factors compared with control macrophages. In vivo, injured corneas treated with cMSC-educated macrophages demonstrate significantly less neovascularization compared with corneas treated with control macrophages. Knocking down the expression of pigment epithelial derived factor (PEDF) in cMSCs significantly abrogates its modulating effects on macrophages, as shown by the reduced rate of apoptosis, decreased expression of sFLT-1/PEDF, and increased expression of vascular endothelial growth factor-A in the cocultured macrophages. Similarly, cMSCs isolated from PEDF knockout mice are less effective compared with wild-type cMSCs at inhibiting macrophage infiltration when applied to wild-type corneas after injury. Overall, these results demonstrate that cMSCs therapeutically suppress the angiogenic capacity of macrophages and highlight the role of cMSC secreted PEDF in the modulation of macrophage phenotype and function. Stem Cells 2018;36:775-784.
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Affiliation(s)
- Medi Eslani
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Ilham Putra
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xiang Shen
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Judy Hamouie
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Asha Tadepalli
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Khandaker N Anwar
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - John A Kink
- Department of Medicine and University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Samaneh Ghassemi
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Gaurav Agnihotri
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Sofiya Reshetylo
- Department of Medicine and University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Alireza Mashaghi
- Faculty of Mathematics and Natural Sciences, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Reza Dana
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Peiman Hematti
- Department of Medicine and University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Ali R Djalilian
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
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Eslani M, Putra I, Shen X, Hamouie J, Afsharkhamseh N, Besharat S, Rosenblatt MI, Dana R, Hematti P, Djalilian AR. Corneal Mesenchymal Stromal Cells Are Directly Antiangiogenic via PEDF and sFLT-1. Invest Ophthalmol Vis Sci 2017; 58:5507-5517. [PMID: 29075761 PMCID: PMC5661382 DOI: 10.1167/iovs.17-22680] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose To evaluate the angiogenic properties of corneal derived mesenchymal stromal cells (Co-MSC). Methods Co-MSCs were extracted from human cadaver, and wild-type (C57BL/6J) and SERPINF1−/− mice corneas. The MSC secretome was collected in a serum-free medium. Human umbilical vein endothelial cell (HUVEC) tube formation and fibrin gel bead assay (FIBA) sprout formation were used to assess the angiogenic properties of Co-MSC secretome. Complete corneal epithelial debridement was used to induce corneal neovascularization in wild-type mice. Co-MSCs embedded in fibrin gel was applied over the debrided cornea to evaluate the angiogenic effects of Co-MSCs in vivo. Immunoprecipitation was used to remove soluble fms-like tyrosine kinase-1 (sFLT-1) and pigment epithelium-derived factor (PEDF, SERPINF1 gene) from the Co-MSC secretome. Results Co-MSC secretome significantly inhibited HUVECs tube and sprout formation. Co-MSCs from different donors consistently contained high levels of antiangiogenic factors including sFLT-1 and PEDF; and low levels of the angiogenic factor VEGF-A. In vivo, application of Co-MSCs to mouse corneas after injury prevented the development of corneal neovascularization. Removing PEDF or sFLT-1 from the secretome significantly diminished the antiangiogenic effects of Co-MSCs. Co-MSCs isolated from SERPINF1−/− mice had significantly reduced antiangiogenic effects compared to SERPINF1+/+ (wild-type) Co-MSCs. Conclusions These results illustrate the direct antiangiogenic properties of Co-MSCs, the importance of sFLT-1 and PEDF, and their potential clinical application for preventing pathologic corneal neovascularization.
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Affiliation(s)
- Medi Eslani
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Ilham Putra
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Xiang Shen
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Judy Hamouie
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Neda Afsharkhamseh
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Soroush Besharat
- Department of Medicine and University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Mark I Rosenblatt
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Reza Dana
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Peiman Hematti
- Department of Medicine and University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Ali R Djalilian
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
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Mesenchymal stem cell therapy to promote corneal allograft survival: current status and pathway to clinical translation. Curr Opin Organ Transplant 2017; 21:559-567. [PMID: 27801687 DOI: 10.1097/mot.0000000000000360] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE OF REVIEW This article reviews the literature on the therapeutic potential of mesenchymal stem cells (MSCs) to prolong corneal allograft survival. RECENT FINDINGS To date, only small numbers studies have investigated the MSC ability to modulate corneal allograft survival. Most reports have shown positive results, which is encouraging, however as different MSC-application strategies (time point of injection, cell number/number of injections, route of injection, MSC source, MSC licensing) have been employed in various animal models it is difficult to compare and validate the results. The MSC ability to promote graft survival has been attributed to their modulation of the recipient immune system, altering the Th1/Th2 balance, expanding Foxp3 regulatory T cells, polarizing macrophages and inhibiting intra-graft infiltration of antigen presenting cells. More in depth analysis is required to elucidate the mechanism of MSC-immunomodulation in vivo. SUMMARY MSCs have shown the potential to modulate corneal allograft rejection in various models using MSCs from different species. In particular for high-risk patients with poor prognosis MSC therapy might be a promising approach to promote corneal allograft survival. First-in-man clinical trials with MSC will hopefully shed new light on MSC-mediated immunomodulation in vivo and contribute to the restoration of vision in patients receiving corneal allografts.
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Klaska IP, Muckersie E, Martin-Granados C, Christofi M, Forrester JV. Lipopolysaccharide-primed heterotolerant dendritic cells suppress experimental autoimmune uveoretinitis by multiple mechanisms. Immunology 2016; 150:364-377. [PMID: 27859049 PMCID: PMC5290303 DOI: 10.1111/imm.12691] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 11/01/2016] [Accepted: 11/08/2016] [Indexed: 12/14/2022] Open
Abstract
Exposure of bone‐marrow‐derived dendritic cells (BMDC) to high‐dose ultrapure lipopolysaccharide for 24 hr (LPS‐primed BMDC) enhances their potency in preventing inter‐photoreceptor retinoid binding protein: complete Freund's adjuvant‐induced experimental autoimmune uveoretinitis (EAU). LPS‐primed BMDC are refractory to further exposure to LPS (= endotoxin tolerance), evidenced here by decreased phosphorylation of TANK‐binding kinase 1, interferon regulatory factor 3 (IRF3), c‐Jun N‐terminal kinase and p38 mitogen‐activated protein kinase as well as impaired nuclear translocation of nuclear factor κB (NF‐κB) and IRF3, resulting in reduced tumour necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), IL‐12 and interferon‐β secretion. LPS‐primed BMDC also show reduced surface expression of Toll‐like receptor‐4 and up‐regulation of CD14, followed by increased apoptosis, mediated via nuclear factor of activated T cells (NFATc)‐2 signalling. LPS‐primed BMDC are not only homotolerant to LPS but are heterotolerant to alternative pathogen‐associated molecular pattern ligands, such as mycobacterial protein extract (Mycobacterium tuberculosis). Specifically, while M. tuberculosis protein extract induces secretion of IL‐1β, TNF‐α and IL‐6 in unprimed BMDC, LPS‐primed BMDC fail to secrete these cytokines in response to M. tuberculosis. We propose that LPS priming of BMDC, by exposure to high doses of LPS for 24 hr, stabilizes their tolerogenicity rather than promoting immunogenicity, and does so by multiple mechanisms, namely (i) generation of tolerogenic apoptotic BMDC through CD14:NFATc signalling; (ii) reduction of NF‐κB and IRF3 signalling and downstream pro‐inflammatory cytokine production; and (iii) blockade of inflammasome activation.
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Affiliation(s)
- Izabela P Klaska
- Institute of Ophthalmology, University College London, London, UK
| | | | | | - Maria Christofi
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - John V Forrester
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK.,Lions Eye Institute, University of Western Australia, Perth, WA, Australia
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Yu T, Rajendran V, Griffith M, Forrester JV, Kuffová L. High-risk corneal allografts: A therapeutic challenge. World J Transplant 2016; 6:10-27. [PMID: 27011902 PMCID: PMC4801785 DOI: 10.5500/wjt.v6.i1.10] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/03/2015] [Accepted: 12/04/2015] [Indexed: 02/05/2023] Open
Abstract
Corneal transplantation is the most common surgical procedure amongst solid organ transplants with a high survival rate of 86% at 1-year post-grafting. This high success rate has been attributed to the immune privilege of the eye. However, mechanisms originally thought to promote immune privilege, such as the lack of antigen presenting cells and vessels in the cornea, are challenged by recent studies. Nevertheless, the immunological and physiological features of the cornea promoting a relatively weak alloimmune response is likely responsible for the high survival rate in “low-risk” settings. Furthermore, although corneal graft survival in “low-risk” recipients is favourable, the prognosis in “high-risk” recipients for corneal graft is poor. In “high-risk” grafts, the process of indirect allorecognition is accelerated by the enhanced innate and adaptive immune responses due to pre-existing inflammation and neovascularization of the host bed. This leads to the irreversible rejection of the allograft and ultimately graft failure. Many therapeutic measures are being tested in pre-clinical and clinical studies to counter the immunological challenge of “high-risk” recipients. Despite the prevailing dogma, recent data suggest that tissue matching together with use of systemic immunosuppression may increase the likelihood of graft acceptance in “high-risk” recipients. However, immunosuppressive drugs are accompanied with intolerance/side effects and toxicity, and therefore, novel cell-based therapies are in development which target host immune cells and restore immune homeostasis without significant side effect of treatment. In addition, developments in regenerative medicine may be able to solve both important short comings of allotransplantation: (1) graft rejection and ultimate graft failure; and (2) the lack of suitable donor corneas. The advances in technology and research indicate that wider therapeutic choices for patients may be available to address the worldwide problem of corneal blindness in both “low-risk” and “high-risk” hosts.
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