|
1
|
Krovi SH, Kuchroo VK. Activation pathways that drive CD4 + T cells to break tolerance in autoimmune diseases . Immunol Rev 2022; 307:161-190. [PMID: 35142369 PMCID: PMC9255211 DOI: 10.1111/imr.13071] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 12/11/2022]
Abstract
Autoimmune diseases are characterized by dysfunctional immune systems that misrecognize self as non-self and cause tissue destruction. Several cell types have been implicated in triggering and sustaining disease. Due to a strong association of major histocompatibility complex II (MHC-II) proteins with various autoimmune diseases, CD4+ T lymphocytes have been thoroughly investigated for their roles in dictating disease course. CD4+ T cell activation is a coordinated process that requires three distinct signals: Signal 1, which is mediated by antigen recognition on MHC-II molecules; Signal 2, which boosts signal 1 in a costimulatory manner; and Signal 3, which helps to differentiate the activated cells into functionally relevant subsets. These signals are disrupted during autoimmunity and prompt CD4+ T cells to break tolerance. Herein, we review our current understanding of how each of the three signals plays a role in three different autoimmune diseases and highlight the genetic polymorphisms that predispose individuals to autoimmunity. We also discuss the drawbacks of existing therapies and how they can be addressed to achieve lasting tolerance in patients.
Collapse
Affiliation(s)
- Sai Harsha Krovi
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Vijay K Kuchroo
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts, USA
- Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| |
Collapse
|
|
2
|
Zajec A, Trebušak Podkrajšek K, Tesovnik T, Šket R, Čugalj Kern B, Jenko Bizjan B, Šmigoc Schweiger D, Battelino T, Kovač J. Pathogenesis of Type 1 Diabetes: Established Facts and New Insights. Genes (Basel) 2022; 13:genes13040706. [PMID: 35456512 PMCID: PMC9032728 DOI: 10.3390/genes13040706] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/13/2022] [Accepted: 04/13/2022] [Indexed: 01/08/2023] Open
Abstract
Type 1 diabetes (T1D) is an autoimmune disease characterized by the T-cell-mediated destruction of insulin-producing β-cells in pancreatic islets. It generally occurs in genetically susceptible individuals, and genetics plays a major role in the development of islet autoimmunity. Furthermore, these processes are heterogeneous among individuals; hence, different endotypes have been proposed. In this review, we highlight the interplay between genetic predisposition and other non-genetic factors, such as viral infections, diet, and gut biome, which all potentially contribute to the aetiology of T1D. We also discuss a possible active role for β-cells in initiating the pathological processes. Another component in T1D predisposition is epigenetic influences, which represent a link between genetic susceptibility and environmental factors and may account for some of the disease heterogeneity. Accordingly, a shift towards personalized therapies may improve the treatment results and, therefore, result in better outcomes for individuals in the long-run. There is also a clear need for a better understanding of the preclinical phases of T1D and finding new predictive biomarkers for earlier diagnosis and therapy, with the final goal of reverting or even preventing the development of the disease.
Collapse
Affiliation(s)
- Ana Zajec
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Katarina Trebušak Podkrajšek
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Tine Tesovnik
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
| | - Robert Šket
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
| | - Barbara Čugalj Kern
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Barbara Jenko Bizjan
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Darja Šmigoc Schweiger
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Tadej Battelino
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Jernej Kovač
- Division of Paediatrics, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (A.Z.); (K.T.P.); (T.T.); (R.Š.); (B.Č.K.); (B.J.B.); (D.Š.S.); (T.B.)
- Department of Paediatrics, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Correspondence:
| |
Collapse
|