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Roe K. Pathogen regulatory RNA usage enables chronic infections, T-cell exhaustion and accelerated T-cell exhaustion. Mol Cell Biochem 2023; 478:2505-2516. [PMID: 36941498 PMCID: PMC10027582 DOI: 10.1007/s11010-023-04680-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 02/15/2023] [Indexed: 03/23/2023]
Abstract
Pathogens evade or disable cellular immune defenses using regulatory ribonucleic acids (RNAs), including microRNAs and long non-coding RNAs. Pathogenic usage of regulatory RNA enables chronic infections. Chronic infections, using host regulatory RNAs and/or creating pathogenic regulatory RNAs against cellular defenses, can cause T-cell exhaustion and latent pathogen reactivations. Concurrent pathogen infections of cells enable several possibilities. A first pathogen can cause an accelerated T-cell exhaustion for a second pathogen cellular infection. Accelerated T-cell exhaustion for the second pathogen weakens T-cell targeting of the second pathogen and enables a first-time infection by the second pathogen to replicate quickly and extensively. This can induce a large antibody population, which may be inadequately targeted against the second pathogen. Accelerated T-cell exhaustion can explain the relatively short median and average times from diagnosis to mortality in some viral epidemics, e.g., COVID-19, where the second pathogen can lethally overwhelm individuals' immune defenses. Alternatively, if an individual survives, the second pathogen could induce a very high titer of antigen-antibody immune complexes. If the antigen-antibody immune complex titer quickly becomes very high, it can exceed the immune system's phagocytic capability in immuno-deficient individuals, resulting in a Type III hypersensitivity immune reaction. Accelerated T-cell exhaustion in immuno-deficient individuals can be a fundamental cause of several hyperinflammatory diseases and autoimmune diseases. This would be possible when impaired follicular helper CD4+ T-cell assistance to germinal center B-cell somatic hypermutation, affinity maturation and isotype switching of antibodies results in high titers of inadequate antibodies, and this initiates a Type III hypersensitivity immune reaction with proteinase releases which express or expose autoantigens.
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Roe K. Accelerated T-cell exhaustion: its potential role in autoimmune disease and hyperinflammatory disease pathogenesis. Hum Cell 2023; 36:866-869. [PMID: 36478089 PMCID: PMC9735067 DOI: 10.1007/s13577-022-00839-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
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Inostroza-Nieves Y, Rivera A, Romero JR. Blockade of endothelin-1 receptor B regulates molecules of the major histocompatibility complex in sickle cell disease. Front Immunol 2023; 14:1124269. [PMID: 36926339 PMCID: PMC10011151 DOI: 10.3389/fimmu.2023.1124269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/16/2023] [Indexed: 03/08/2023] Open
Abstract
Major Histocompatibility Complex (MHC) molecules have been proposed to play a role in Sickle Cell Disease (SCD) pathophysiology. Endothelial cells express MHC molecules following exposure to cytokines. SCD is characterized, in part, by vascular endothelial cell activation, increased oxidative stress, sickle cell adhesion, and excess levels of endothelin-1 (ET-1) contributing to vaso-occlusive crises. ET-1 activates endothelial cells, induces oxidative stress and inflammation, and alters erythrocyte volume homeostasis. However, the role of ET-1 on MHC regulation in SCD is unclear. We first studied two sickle transgenic knockout mouse models of moderate to severe disease phenotype, βS-Antilles and Berkeley (BERK) mice. We observed significant increases in H2-Aa mRNA levels in spleens, lungs, and kidneys from transgenic sickle mice when compared to transgenic knockout mice expressing human hemoglobin A (HbA). Mice treated for 14 days with ET-1 receptor antagonists significantly reduced H2-Aa mRNA levels. We characterized the effect of ET-1 on MHC class II expression in the human endothelial cell line EA.hy926. We observed dose-dependent increases in the expression of MHC class II (HLA-DRA) and MHC transcription factor (CIITA) that were significantly blocked by treatment with BQ788, a selective blocker of ET-1 type B receptors. Chromatin immunoprecipitation studies in EA.hy926 cells showed that ET-1 increased Histone H3 acetylation of the HLA-DRA promoter, an event blocked by BQ788 treatment. These results implicate ET-1 as a novel regulator of MHC class II molecules and suggest that ET-1 receptor blockade represents a promising therapeutic approach to regulate both immune and vascular responses in SCD.
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Affiliation(s)
- Yaritza Inostroza-Nieves
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA, United States.,Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA, United States.,Department of Biochemistry and Pharmacology, San Juan Bautista School of Medicine, Caguas, Puerto Rico
| | - Alicia Rivera
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA, United States.,Department of Pathology, Harvard Medical School, Boston, MA, United States.,Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States
| | - José R Romero
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA, United States
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