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Leung J, Qu L, Ye Q, Zhong Z. The immune duality of osteopontin and its therapeutic implications for kidney transplantation. Front Immunol 2025; 16:1520777. [PMID: 40093009 PMCID: PMC11906708 DOI: 10.3389/fimmu.2025.1520777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2024] [Accepted: 02/10/2025] [Indexed: 03/19/2025] Open
Abstract
Osteopontin (OPN) is a multifunctional glycoprotein with various structural domains that enable it to perform diverse functions in both physiological and pathological states. This review comprehensively examines OPN from multiple perspectives, including its protein structure, interactions with receptors, interactions with immune cells, and roles in kidney diseases and transplantation. This review explores the immunological duality of OPN and its significance and value as a biomarker and therapeutic target in kidney transplantation. In cancer, OPN typically promotes tumor evasion by suppressing the immune system. Conversely, in immune-related kidney diseases, particularly kidney transplantation, OPN activates the immune system by enhancing the migration and activation of immune cells, thereby exacerbating kidney damage. This immunological duality may stem from different OPN splice variants and the exposure, after cleavage, of different structural domains, which play distinct biological roles in cellular interactions. Additionally, OPN has a significant biological impact posttransplantation and on chronic kidney disease and, highlighting its importance as a biomarker and potential therapeutic target. Future research should further explore the specific mechanisms of OPN in kidney transplantation to improve treatment strategies and enhance patient quality of life.
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Affiliation(s)
- Junto Leung
- Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Provincial Clinical Research Center for Natural Polymer Biological Liver, Wuhan, Hubei, China
| | - Lei Qu
- Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Provincial Clinical Research Center for Natural Polymer Biological Liver, Wuhan, Hubei, China
| | - Qifa Ye
- Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Provincial Clinical Research Center for Natural Polymer Biological Liver, Wuhan, Hubei, China
- The 3rd Xiangya Hospital of Central South University, NHC Key Laboratory of Translational Research on Transplantation Medicine, Changsha, China
| | - Zibiao Zhong
- Zhongnan Hospital of Wuhan University, Institute of Hepatobiliary Diseases of Wuhan University, Transplant Center of Wuhan University, National Quality Control Center for Donated Organ Procurement, Hubei Key Laboratory of Medical Technology on Transplantation, Hubei Provincial Clinical Research Center for Natural Polymer Biological Liver, Wuhan, Hubei, China
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Soysouvanh F, Rousseau D, Bonnafous S, Bourinet M, Strazzulla A, Patouraux S, Machowiak J, Farrugia MA, Iannelli A, Tran A, Anty R, Luci C, Gual P. Osteopontin-driven T-cell accumulation and function in adipose tissue and liver promoted insulin resistance and MAFLD. Obesity (Silver Spring) 2023; 31:2568-2582. [PMID: 37724058 DOI: 10.1002/oby.23868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 09/20/2023]
Abstract
OBJECTIVE This study investigated the contribution of osteopontin/secreted phosphoprotein 1 (SPP1) to T-cell regulation in initiation of obesity-driven adipose tissue (AT) inflammation and macrophage infiltration and the subsequent impact on insulin resistance (IR) and metabolic-associated fatty liver disease (MAFLD) development. METHODS SPP1 and T-cell marker expression was evaluated in AT and liver according to type 2 diabetes and MAFLD in human individuals with obesity. The role of SPP1 on T cells was evaluated in Spp1-knockout mice challenged with a high-fat diet. RESULTS In humans with obesity, elevated SPP1 expression in AT was parallel to T-cell marker expression (CD4, CD8A) and IR. Weight loss reversed AT inflammation with decreased SPP1 and CD8A expression. In liver, elevated SPP1 expression correlated with MAFLD severity and hepatic T-cell markers. In mice, although Spp1 deficiency did not impact obesity, it did improve AT IR associated with prevention of proinflammatory T-cell accumulation at the expense of regulatory T cells. Spp1 deficiency also decreased ex vivo helper T cell, subtype 1 (Th1) polarization of AT CD4+ and CD8+ T cells. In addition, Spp1 deficiency significantly reduced obesity-associated liver steatosis and inflammation. CONCLUSIONS Current findings highlight a critical role of SPP1 in the initiation of obesity-driven chronic inflammation by regulating accumulation and/or polarization of T cells. Early targeting of SPP1 could be beneficial for IR and MAFLD treatment.
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Affiliation(s)
| | | | | | - Manon Bourinet
- Université Côte d'Azur, INSERM, U1065, C3M, Nice, France
| | | | | | - Jean Machowiak
- Université Côte d'Azur, INSERM, U1065, C3M, Nice, France
| | | | | | - Albert Tran
- Université Côte d'Azur, CHU, INSERM, U1065, C3M, Nice, France
| | - Rodolphe Anty
- Université Côte d'Azur, CHU, INSERM, U1065, C3M, Nice, France
| | - Carmelo Luci
- Université Côte d'Azur, INSERM, U1065, C3M, Nice, France
| | - Philippe Gual
- Université Côte d'Azur, INSERM, U1065, C3M, Nice, France
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Onogi Y, Khalil AEMM, Ussar S. Identification and characterization of adipose surface epitopes. Biochem J 2020; 477:2509-2541. [PMID: 32648930 PMCID: PMC7360119 DOI: 10.1042/bcj20190462] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 12/14/2022]
Abstract
Adipose tissue is a central regulator of metabolism and an important pharmacological target to treat the metabolic consequences of obesity, such as insulin resistance and dyslipidemia. Among the various cellular compartments, the adipocyte cell surface is especially appealing as a drug target as it contains various proteins that when activated or inhibited promote adipocyte health, change its endocrine function and eventually maintain or restore whole-body insulin sensitivity. In addition, cell surface proteins are readily accessible by various drug classes. However, targeting individual cell surface proteins in adipocytes has been difficult due to important functions of these proteins outside adipose tissue, raising various safety concerns. Thus, one of the biggest challenges is the lack of adipose selective surface proteins and/or targeting reagents. Here, we discuss several receptor families with an important function in adipogenesis and mature adipocytes to highlight the complexity at the cell surface and illustrate the problems with identifying adipose selective proteins. We then discuss that, while no unique adipocyte surface protein might exist, how splicing, posttranslational modifications as well as protein/protein interactions can create enormous diversity at the cell surface that vastly expands the space of potentially unique epitopes and how these selective epitopes can be identified and targeted.
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Affiliation(s)
- Yasuhiro Onogi
- RG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Ahmed Elagamy Mohamed Mahmoud Khalil
- RG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Siegfried Ussar
- RG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
- Department of Medicine, Technische Universität München, Munich, Germany
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