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Cassano A, Chong AS, Alegre ML. Tregs in transplantation tolerance: role and therapeutic potential. FRONTIERS IN TRANSPLANTATION 2023; 2:1217065. [PMID: 38993904 PMCID: PMC11235334 DOI: 10.3389/frtra.2023.1217065] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/14/2023] [Indexed: 07/13/2024]
Abstract
CD4+ Foxp3+ regulatory T cells (Tregs) are indispensable for preventing autoimmunity, and they play a role in cancer and transplantation settings by restraining immune responses. In this review, we describe evidence for the importance of Tregs in the induction versus maintenance of transplantation tolerance, discussing insights into mechanisms of Treg control of the alloimmune response. Further, we address the therapeutic potential of Tregs as a clinical intervention after transplantation, highlighting engineered CAR-Tregs as well as expansion of donor and host Tregs.
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Affiliation(s)
- Alexandra Cassano
- Department of Medicine, University of Chicago, Chicago, IL, United States
| | - Anita S. Chong
- Department of Surgery, University of Chicago, Chicago, IL, United States
| | - Maria-Luisa Alegre
- Department of Medicine, University of Chicago, Chicago, IL, United States
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Abdeladhim M, Karnell JL, Rieder SA. In or out of control: Modulating regulatory T cell homeostasis and function with immune checkpoint pathways. Front Immunol 2022; 13:1033705. [PMID: 36591244 PMCID: PMC9799097 DOI: 10.3389/fimmu.2022.1033705] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/16/2022] [Indexed: 12/16/2022] Open
Abstract
Regulatory T cells (Tregs) are the master regulators of immunity and they have been implicated in different disease states such as infection, autoimmunity and cancer. Since their discovery, many studies have focused on understanding Treg development, differentiation, and function. While there are many players in the generation and function of truly suppressive Tregs, the role of checkpoint pathways in these processes have been studied extensively. In this paper, we systematically review the role of different checkpoint pathways in Treg homeostasis and function. We describe how co-stimulatory and co-inhibitory pathways modulate Treg homeostasis and function and highlight data from mouse and human studies. Multiple checkpoint pathways are being targeted in cancer and autoimmunity; therefore, we share insights from the clinic and discuss the effect of experimental and approved therapeutics on Treg biology.
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Mittal SK, Cho W, Elbasiony E, Guan Y, Foulsham W, Chauhan SK. Mesenchymal stem cells augment regulatory T cell function via CD80-mediated interactions and promote allograft survival. Am J Transplant 2022; 22:1564-1577. [PMID: 35170213 PMCID: PMC11261724 DOI: 10.1111/ajt.17001] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/25/2022] [Accepted: 02/09/2022] [Indexed: 02/05/2023]
Abstract
Mesenchymal stem cells (MSCs) and regulatory T cells (Tregs) both have been shown to modulate the alloimmune response and promote transplant survival. Mounting evidence suggests that MSCs augment Treg function, but the mechanisms underlying this phenomenon have not been fully deciphered. Here, we identified that MSCs express substantial levels of CD80 and evaluated its immunoregulatory function using in vivo and in vitro experiments. Our in vitro culture assays demonstrated that MSCs induce expression of FoxP3 in Tregs in a contact-dependent manner, and the blockade of CD80 abrogates this FoxP3 induction and Treg-mediated suppression of T cell proliferation. Moreover, supplementation of soluble CD80 significantly upregulated FoxP3 expression. Using a well-characterized murine model of corneal transplantation, we show that silencing CD80 in MSCs diminishes the capacity of MSCs to promote selective graft infiltration of Tregs, promote FoxP3 expression and upregulate suppressive function of Tregs. Consequently, MSCs, following CD80 knockdown, failed to promote corneal allograft survival.
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Affiliation(s)
- Sharad K Mittal
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - WonKyung Cho
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Elsayed Elbasiony
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Yilin Guan
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - William Foulsham
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Sunil K Chauhan
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
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Schönberg A, Hamdorf M, Bock F. Immunomodulatory Strategies Targeting Dendritic Cells to Improve Corneal Graft Survival. J Clin Med 2020; 9:E1280. [PMID: 32354200 PMCID: PMC7287922 DOI: 10.3390/jcm9051280] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/08/2020] [Accepted: 04/21/2020] [Indexed: 12/16/2022] Open
Abstract
Even though the cornea is regarded as an immune-privileged tissue, transplantation always comes with the risk of rejection due to mismatches between donor and recipient. It is common sense that an alternative to corticosteroids as the current gold standard for treatment of corneal transplantation is needed. Since blood and lymphatic vessels have been identified as a severe risk factor for corneal allograft survival, much research has focused on vessel regression or inhibition of hem- and lymphangiogenesis in general. However, lymphatic vessels have been identified as required for the inflammation's resolution. Therefore, targeting other players of corneal engraftment could reveal new therapeutic strategies. The establishment of a tolerogenic microenvironment at the graft site would leave the recipient with the ability to manage pathogenic conditions independent from transplantation. Dendritic cells (DCs) as the central player of the immune system represent a target that allows the induction of tolerogenic mechanisms by many different strategies. These strategies are reviewed in this article with regard to their success in corneal transplantation.
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Affiliation(s)
- Alfrun Schönberg
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (A.S.); (M.H.)
| | - Matthias Hamdorf
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (A.S.); (M.H.)
| | - Felix Bock
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (A.S.); (M.H.)
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50937 Cologne, Germany
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Tahvildari M, Inomata T, Amouzegar A, Dana R. Regulatory T cell modulation of cytokine and cellular networks in corneal graft rejection. CURRENT OPHTHALMOLOGY REPORTS 2018; 6:266-274. [PMID: 31807370 PMCID: PMC6894425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
PURPOSE OF REVIEW Corneal allografts placed in vascularized or inflamed host beds are at increased risk of graft rejection due to the preponderance of activated immune cells in the host bed. Regulatory T cells (Tregs) are master regulators of the adaptive immune response and play a key role in the induction of immune tolerance. The aim of this review is to discuss mechanisms through which Tregs mediate tolerance in corneal transplantation and the novel therapeutic approaches that target Tregs to promote transplant survival. RECENT FINDINGS The inflammatory environment of high-risk allografts not only promotes activation of effector T cells and their infiltration to graft site, but also impairs Treg immunomodulatory function. Recent studies have shown that expansion of Tregs and enhancing their modulatory function significantly improve graft survival. SUMMARY As our understanding of the cellular and molecular pathways in corneal transplantation has deepened, novel therapeutic strategies have been developed to improve allograft survival. In this review, we discuss therapeutic approaches that focus on Tregs to promote corneal allograft survival.
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Affiliation(s)
- Maryam Tahvildari
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
- Kresge Eye Institute, Department of ophthalmology, Wayne State University, Detroit, MI
| | - Takenori Inomata
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
- Juntendo University Faculty of Medicine, Department of Ophthalmology, Tokyo, Japan
- Juntendo University Faculty of Medicine, Department of Strategic Operative Room, Management and Improvement, Tokyo, Japan
| | - Afsaneh Amouzegar
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Reza Dana
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA
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Tahvildari M, Inomata T, Amouzegar A, Dana R. Regulatory T Cell Modulation of Cytokine and Cellular Networks in Corneal Graft Rejection. CURRENT OPHTHALMOLOGY REPORTS 2018. [DOI: 10.1007/s40135-018-0191-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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The Effects of Anti-LAP Monoclonal Antibody Down-regulation of CD4+LAP+ T Cells on Allogeneic Corneal Transplantation in Mice. Sci Rep 2018; 8:8021. [PMID: 29789580 PMCID: PMC5964070 DOI: 10.1038/s41598-018-26235-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/25/2018] [Indexed: 01/28/2023] Open
Abstract
CD4+latency-associated peptide (LAP)+ T cells are a newly discovered T cell subset with suppressive function on immune responses. In this study, we investigate the role of CD4+LAP+ T cells on mice corneal allograft survival by down-regulating their expression using anti-LAP mAb. We show that a blockage of LAP leads to a decrease in the percentage of T cells expressing CD4+Foxp3+, CD4+GARP+, CD4+LAP+ and CD4+IL-10+ in the lymph nodes and spleens of mice undergoing orthotopic penetrating transplantation of corneal allograft, without affecting corneal graft survival. In addition, higher percentages of CD4+IFN-γ+ and CD4+IL-17A+ T cells in the lymph nodes and spleens, as well as TNF, IFN-γ, IL-17A and IL-6 levels in the aqueous humor, significantly increase in mice with rejected corneal grafts. The expression of TGF-β1 decreases in corneal grafts during corneal rejection period. It is therefore possible that anti-LAP mAb can down-regulate the regulatory T cell subsets with its immunosuppressive effects. The rejection of corneal grafts seems to mainly be associated with the up-regulation of Th1 and Th17 cell subsets in peripheral lymph nodes.
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Abstract
PURPOSE To assess the effect of dry eye disease (DED) in graft donors on dendritic cell (DC) maturation, host T-cell sensitization, and corneal allograft rejection. METHODS Corneas of control (healthy donor) and DED mice (C57BL/6) were transplanted onto fully allogeneic naive BALB/c recipients (n = 10 mice/group). Long-term allograft survival was evaluated for 8 weeks. Corneas and draining lymph nodes (dLNs) were harvested at posttransplantation day 14 (n = 5 mice/group). The frequencies of MHCII CD11c DCs in the donor corneas and host dLNs and the frequencies of interferon (IFN)-γ and IL-17 CD4 T cells and Foxp3 expression by Tregs in host dLNs were investigated using flow cytometry. The enzyme-linked immunospot assay was used to assess host T-cell allosensitization through direct and indirect pathways (n = 3/group). RESULTS Recipients of DED donor corneas showed significantly reduced graft survival (10%) compared with control mice (50% survival, P = 0.022), and had significantly increased frequencies of mature DCs in the grafted cornea (DED donor 44.0% ± 0.36% vs. healthy donor 35.4 ± 0.5%; P < 0.0001) and host dLNs (DED donor 25.1% ± 0.66% vs. healthy donor 13.7% ± 1.6%; P = 0.005). Frequencies of IFN-γ and IL-17 T cells were increased in the dLNs of recipients of DED corneas, whereas the expression (mean fluorescence intensity) of Foxp3 in Tregs was decreased significantly in these mice (DED donor 6004 ± 193 vs. healthy donor 6806 ± 81; P = 0.0002). Enzyme-linked immunospot analysis showed that the direct pathway of allosensitization was significantly amplified in recipients of grafts with DED (P = 0.0146). CONCLUSIONS Our results indicate that DED in the donor is a significant risk factor for subsequent corneal allograft rejection.
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Tahvildari M, Amouzegar A, Foulsham W, Dana R. Therapeutic approaches for induction of tolerance and immune quiescence in corneal allotransplantation. Cell Mol Life Sci 2018; 75:1509-1520. [PMID: 29307015 DOI: 10.1007/s00018-017-2739-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 12/12/2017] [Accepted: 12/27/2017] [Indexed: 01/08/2023]
Abstract
The cornea is the most commonly transplanted tissue in the body. Corneal grafts in low-risk recipients enjoy high success rates, yet over 50% of high-risk grafts (with inflamed and vascularized host beds) are rejected. As our understanding of the cellular and molecular pathways that mediate rejection has deepened, a number of novel therapeutic strategies have been unveiled. This manuscript reviews therapeutic approaches to promote corneal transplant survival through targeting (1) corneal lymphangiogenesis and hemangiogenesis, (2) antigen presenting cells, (3) effector and regulatory T cells, and (4) mesenchymal stem cells.
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Affiliation(s)
- Maryam Tahvildari
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.,Kresge Eye Institute, Wayne State University, Detroit, MI, USA
| | - Afsaneh Amouzegar
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - William Foulsham
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Reza Dana
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA.
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Tolerogenic Dendritic Cells on Transplantation: Immunotherapy Based on Second Signal Blockage. J Immunol Res 2015; 2015:856707. [PMID: 26543876 PMCID: PMC4620289 DOI: 10.1155/2015/856707] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/23/2015] [Accepted: 06/29/2015] [Indexed: 12/16/2022] Open
Abstract
Dendritic cells (DCs), the most important professional antigen-presenting cells (APC), play crucial role in both immunity and tolerance. It is well known that DCs are able to mount immune responses against foreign antigens and simultaneously tolerate self-antigens. Since DCs can be modulated depending on the surrounding microenvironment, they can act as a bridge between innate and adaptive immunity. However, the mechanisms that support this dual role are not entirely clear. Recent studies have shown that DCs can be manipulated ex vivo in order to trigger their tolerogenic profile, what can be a tool to be used in clinical trials aiming the treatment of various diseases and the prevention of transplant rejection. In this sense, the blockage of costimulatory molecules on DC, in the attempt of inhibiting the second signal in the immunological synapse, can be considered as one of the main strategies under development. This review brings an update on current therapies using tolerogenic dendritic cells modulated with costimulatory blockers with the aim of reducing transplant rejection. However, although there are current clinical trials using tolerogenic DC to treat allograft rejection, the actual challenge is to modulate these cells in order to maintain a permanent tolerogenic profile.
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Glowacki AJ, Gottardi R, Yoshizawa S, Cavalla F, Garlet GP, Sfeir C, Little SR. Strategies to direct the enrichment, expansion, and recruitment of regulatory cells for the treatment of disease. Ann Biomed Eng 2014; 43:593-602. [PMID: 25245220 DOI: 10.1007/s10439-014-1125-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 09/12/2014] [Indexed: 01/21/2023]
Abstract
Disease and injury perturb the balance of processes associated with inflammation and tissue remodeling, resulting in positive feedback loops, exacerbation of disease and compromised tissue repair. Conversely, under homeostatic healthy conditions, these processes are tightly regulated through the expansion and/or recruitment of specific cell populations, promoting a balanced steady-state. Better understanding of these regulatory processes and recent advances in biomaterials and biotechnology have prompted strategies to utilize cells for the treatment and prevention of disease through regulation of inflammation and promotion of tissue repair. Herein, we describe how cells that regulate these processes can be increased in prevalence at a site of disease or injury. We review several relevant cell therapy approaches as well as new strategies for directing endogenous regulatory cells capable of promoting environmental homeostasis and even the establishment of a pro-regenerative micro-environment. Collectively, these examples may provide a blueprint for next-generation "medicine" that spurs the body's own cells to action and replaces conventional drugs.
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Affiliation(s)
- Andrew J Glowacki
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, USA
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