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Vereertbrugghen A, Pizzano M, Sabbione F, Keitelman IA, Shiromizu CM, Aguilar DV, Fuentes F, de Paiva CS, Giordano M, Trevani A, Galletti JG. An ocular Th1 immune response promotes corneal nerve damage independently of the development of corneal epitheliopathy. J Neuroinflammation 2023; 20:120. [PMID: 37217914 PMCID: PMC10201717 DOI: 10.1186/s12974-023-02800-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 05/09/2023] [Indexed: 05/24/2023] Open
Abstract
Proper sight is not possible without a smooth, transparent cornea, which is highly exposed to environmental threats. The abundant corneal nerves are interspersed with epithelial cells in the anterior corneal surface and are instrumental to corneal integrity and immunoregulation. Conversely, corneal neuropathy is commonly observed in some immune-mediated corneal disorders but not in others, and its pathogenesis is poorly understood. Here we hypothesized that the type of adaptive immune response may influence the development of corneal neuropathy. To test this, we first immunized OT-II mice with different adjuvants that favor T helper (Th)1 or Th2 responses. Both Th1-skewed mice (measured by interferon-γ production) and Th2-skewed (measured by interleukin-4 production) developed comparable ocular surface inflammation and conjunctival CD4+ T cell recruitment but no appreciable corneal epithelial changes upon repeated local antigenic challenge. Th1-skewed mice showed decreased corneal mechanical sensitivity and altered corneal nerve morphology (signs of corneal neuropathy) upon antigenic challenge. However, Th2-skewed mice also developed milder corneal neuropathy immediately after immunization and independently of ocular challenge, suggestive of adjuvant-induced neurotoxicity. All these findings were confirmed in wild-type mice. To circumvent unwanted neurotoxicity, CD4+ T cells from immunized mice were adoptively transferred to T cell-deficient mice. In this setup, only Th1-transferred mice developed corneal neuropathy upon antigenic challenge. To further delineate the contribution of each profile, CD4+ T cells were polarized in vitro to either Th1, Th2, or Th17 cells and transferred to T cell-deficient mice. Upon local antigenic challenge, all groups had commensurate conjunctival CD4+ T cell recruitment and macroscopic ocular inflammation. However, none of the groups developed corneal epithelial changes and only Th1-transferred mice showed signs of corneal neuropathy. Altogether, the data show that corneal nerves, as opposed to corneal epithelial cells, are sensitive to immune-driven damage mediated by Th1 CD4+ T cells in the absence of other pathogenic factors. These findings have potential therapeutic implications for ocular surface disorders.
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Affiliation(s)
- Alexia Vereertbrugghen
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Manuela Pizzano
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Florencia Sabbione
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Irene Angelica Keitelman
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Carolina Maiumi Shiromizu
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Douglas Vera Aguilar
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Federico Fuentes
- Confocal Microscopy Unit, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Cintia S de Paiva
- Department of Ophthalmology, Ocular Surface Center, Cullen Eye Institute, Baylor College of Medicine, Houston, TX, USA
| | - Mirta Giordano
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Analía Trevani
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Jeremías G Galletti
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina.
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Corneal nerves and their role in dry eye pathophysiology. Exp Eye Res 2022; 222:109191. [PMID: 35850173 DOI: 10.1016/j.exer.2022.109191] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/15/2022] [Accepted: 07/11/2022] [Indexed: 12/11/2022]
Abstract
As the cornea is densely innervated, its nerves are integral not only to its structure but also to its pathophysiology. Corneal integrity depends on a protective tear film that is maintained by corneal sensation and the reflex arcs that control tearing and blinking. Furthermore, corneal nerves promote epithelial growth and local immunoregulation. Thus, corneal nerves constitute pillars of ocular surface homeostasis. Conversely, the abnormal tear film in dry eye favors corneal epithelial and nerve damage. The ensuing corneal nerve dysfunction contributes to dry eye progression, ocular pain and discomfort, and other neuropathic symptoms. Recent evidence from clinical studies and animal models highlight the significant but often overlooked neural dimension of dry eye pathophysiology. Herein, we review the anatomy and physiology of corneal nerves before exploring their role in the mechanisms of dry eye disease.
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Modulation of Oxidative Stress and Inflammation in the Aged Lacrimal Gland. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 191:294-308. [PMID: 33159886 DOI: 10.1016/j.ajpath.2020.10.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/05/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022]
Abstract
Inflammation and oxidative stress accompany aging. This study investigated the interplay between oxidative stress and inflammation in the lacrimal gland. C57BL/6 mice were used at 2 to 3, 12, and 24 months of age. Nuclear factor erythroid derived-2-related factor 2 (Nrf2)-/- and corresponding wild-type mice were used at 2 to 3 and 12 to 13 months of age. A separate group of 15.5 to 17 months of age C57BL/6 mice received a diet containing an Nrf2 inducer (Oltipraz) for 8 weeks. Aged C57BL/6 lacrimal glands showed significantly greater lymphocytic infiltration, higher levels of MHC II, IFN-γ, IL-1β, TNF-α, and cathepsin S (Ctss) mRNA transcripts, and greater nitrotyrosine and 4-hydroxynonenal protein. Young Nrf2-/- mice showed an increase in IL-1β, IFN-γ, MHC II, and Ctss mRNA transcripts compared with young wild-type mice and greater age-related changes at 12 to 13 months of age. Oltipraz diet significantly decreased nitrotyrosine and 4-hydroxynonenal and decreased the expression of IL-1β and TNF-α mRNA transcripts, while decreasing the frequency of CD45+CD4+ cells in lacrimal glands and significantly increasing conjunctival goblet cell density compared with a standard diet. The findings provide novel insight into the development of chronic, low-grade inflammation and oxidative stress in age-related dry eye. New therapies targeting oxidative stress pathways will be valuable in treating age-related dry eye.
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