Desiccating Stress–Induced Chemokine Expression in the Epithelium Is Dependent on Upregulation of NKG2D/RAE-1 and Release of IFN-γ in Experimental Dry Eye

Abstract

The Th1-associated chemokines CXCL-9, CXCL-10, CXCL-11 coordinate migration of CXCR3+Th1 cells. The objective of this study was to evaluate the role of the innate immune system in stimulating chemokine expression in an experimental model of dry eye and bridge the gap between innate and adaptive immunity. Desiccating stress (DS) induced very early (six hours) expression and production of Th1-associated chemokine in cornea and conjunctiva of C57BL/6 and recombination activating gene 1 (RAG1) knock out (KO) strains, demonstrating that chemokine expression does not require innate T cells. We then demonstrated that activating the innate immune system prior to adoptive transfer of T cells to RAG1KO increased disease severity. Interestingly, lack of induction of chemokines CXCL-9, CXCL-10, CXCL-11 in IFN-γKO mice, provided evidence that their expression requires IFN-γ for induction. Treatment of RAG1KO mice with anti-NK1.1 prevented the increase of CXCL9, CXCL10, and CXCL11 in response to DS, compared to isotype controls. Additionally, DS increased the expression of NKG2D in the conjunctiva. The expression of the NKG2D ligand, RAE-1, also increased at the ocular surface at both the protein and gene level. Neutralization of NKG2D at the ocular surface decreased the expression of CXCL-9, CXCL-10, CXCL-11 and IFN-γ. In summary, upregulation of CXCL9, CXCL-10, and CXCL-11 expression in experimental dry eye is T cell independent, requiring IFN-γ-producing NKG2D+ NK cells that are activated in response to DS induced stress signals. This work provides insight about the events that trigger the initial immune response in dry eye pathology.

Regulation Roles of MICA and NKG2D in Human Renal Cancer Cells

“…Approximately 90% of RCC lesions express MHC class I antigens, in recent years, some highly diversified MHCI-related molecules MICA/B are major ligands of NKG2D and are often expressed in tumor cells. NK cells can recognize tumor cells that have down-regulated MHC class I Ag expression (Wang et al, 2014;Coursey et al, 2014). Through NKG2D, NK cells may identify the target cells structures, such as MHC class I chain-related molecule A (MICA) and MICB, that normally are not expressed or are present in very low density but become up-regulated in transformed cells.…”

“…The cytolytic activity of NK cells against tumor cell lines was recognized very early and it is now becoming evident that several characteristics of tumor cells may induce NK cell-mediated antitumor reactivity (Doubrovina et al, 2003 ;Coursey et al, 2014;Wang et al, 2014). NKG2D is an activating receptor of natural killer cells newly discovered in recent years, which is thought to play an important role in tumor immune surveillance (Lanier, 2001;Matusali et al, 2013;Cho et al, 2014).…”

Improvement of Outcome Measures of Dry Eye by a Novel Integrin Antagonist in the Murine Desiccating Stress Model

“…3,16,18,[27][28][29] The expression of many cytokines and chemokines is increased in the cornea and conjunctiva, resulting in elevated levels in the tear film. In this study, topical GW559090 inhibited the expression of IL-1a, MMP-9, CXCL9, and TGFb1 in the corneal epithelium, and of TGFb1 in the conjunctiva.…”

“…These genes were chosen since they are highly inducible by DS. 3,8,16,18,20 Both experimental groups and the untreated, nonstressed control group had similar expression levels of the housekeeping gene, HPRT-1. Experimental groups were calibrated to nonstressed control.…”

“…3,18,19 We investigated the expression of IL-1a, TGF-b1, MMP-9, and CXCL9 in cornea and conjunctiva using mice that were treated topically with GW559090 at 30 mg/mL during 5 days of DS and compared to vehicle-dosed mice. These genes were chosen since they are highly inducible by DS.…”