Corneal Epithelium–Derived Netrin-1 Alleviates Dry Eye Disease via Regulating Dendritic Cell Activation

Abstract

Purpose To investigate the expression of corneal epithelium–derived netrin-1 (NTN-1) and its immunoregulatory function in dry eye disease (DED) using a DED mouse model. Methods We generated DED mouse models with desiccating stress under scopolamine treatment. RNA sequencing was performed to identify differentially expressed genes (DEGs) in the corneal epithelium of DED mice. NTN-1 expression was analyzed via real-time PCR, immunofluorescence staining, and immunoblotting. The DED mice were then treated with recombinant NTN-1 or neutralizing antibodies to investigate the severity of the disease, dendritic cell (DC) activation, and inflammatory cytokine expression. Results A total of 347 DEGs (292 upregulated and 55 downregulated) were identified in the corneal epithelium of DED mice: corneal epithelium–derived NTN-1 expression was significantly decreased in DED mice compared to that in control mice. Topical recombinant NTN-1 application alleviated the severity of the disease, accompanied by restoration of tear secretion and goblet cell density. In addition, NTN-1 decreased the number of DCs, inhibited the activation of the DCs and Th17 cells, and reduced the expression of inflammatory factors in DED mice. In contrast, blocking endogenous NTN-1 activity with an anti–NTN-1 antibody aggravated the disease, enhanced DC activation, and upregulated the inflammatory factors in the conjunctivae of DED mice. Conclusions We identified decreased NTN-1 expression in the corneal epithelium of DED mice. Our findings elucidate the role of NTN-1 in alleviating DED and impeding DC activation, thereby indicating its therapeutic potential in suppressing ocular inflammation in DED.

Suppression of NLRP3/Caspase-1/GSDMD Mediated Corneal Epithelium Pyroptosis Using Melatonin-Loaded Liposomes to Inhibit Benzalkonium Chloride-Induced Dry Eye Disease

“…Notably, the drug was mainly distributed in the epithelium of the cornea, which may benefit DED therapy as the DED was characterized by the abnormal corneal epithelium. 50

Figure 5 The effects of TAT modification on the retention of drugs in the cornea. ( a ) The changes of MT contents in the cornea, and ( b ) the calculated area under the curve (AUCs).

…”

Ocular surface immune cell diversity in dry eye disease

“…[ 10 , 43 - 53 ] Numerous in vivo studies have confirmed similar altered status of DCs in cornea, conjunctiva and lacrimal gland, and its plausible contribution or mechanism to disease pathogenesis in DED. [ 54 - 60 ] The clinical relevance of DCs can be appreciated with its strong association with DED clinical parameters in patients and the mechanistic studies in the animal models of DED. As illustrated in Fig.…”

“…T cell subsets that were investigated in animal models of DED include CD4+ T cells,[ 70 , 76 , 82 - 84 ] CD8+ T cells,[ 76 ] central memory T cells,[ 85 ] effector memory T cells,[ 85 ] Th1 cells,[ 38 , 86 - 88 ] Th2 cells,[ 89 ] Th17 cells,[ 38 , 60 , 88 , 90 - 92 ] and T regulatory cells – Tregs. [ 38 , 39 , 86 , 90 , 91 ] Increase in ocular surface CD4+ T cells,[ 70 , 76 , 82 - 84 ] CD8+ T cells,[ 76 ] Th1 cells,[ 86 , 87 ] and Th17 cells,[ 60 , 88 , 90 - 92 ] and a decrease in the ocular surface Tregs,[ 86 , 90 ] have been observed in various DED animal models. Contrary to the observations made in a human study,[ 81 ] a decrease in naïve T cells and central memory, along with an increase in effector memory T cells in the eye tissues of DED animals.…”

“…Topical administration of netrin-1,[ 60 ] PEDF,[ 61 ] COX-2 inhibitor,[ 57 ] and TRPV1 channel blockade[ 65 ] have shown suppression of DC activation, maturation, migration, related ocular surface inflammation, and DED severity. Treatment with resolvin,[ 70 ] PEDF,[ 68 ] CCR7 blockade,[ 67 ] or IL-20 blockade[ 69 ] resulted in the reduction of ocular surface infiltration of macrophages, migration of macrophages to lymph nodes, ocular surface inflammation and DED severity in animal models.…”

“…Anti-TNF,[ 82 ] polyphenols – quercetin and resveratrol,[ 83 ] diquafosol sodium,[ 87 ] dexamethasone,[ 74 ] cyclosporine,[ 106 ] voclosporin, a calcineurin inhibitor,[ 94 ] GW559090, a α4β1 integrin antagonist,[ 73 ] resolvin,[ 70 ] and IL-17 blockade[ 80 ] treatments reduced ocular surface infiltration and activation of T cells in DED animal models. Lifitegrast,[ 105 ] CCL20 neutralization,[ 107 ] erxian decoction,[ 90 ] rebamipide,[ 91 ] and netrin-1[ 60 ] were reported to reduce the infiltration and trafficking of Th17 subsets on to the ocular surface and restored normal ocular surface parameters in various animal models of DED. Studies have also shown the beneficial regulation of Th17 and Treg cells in DED models.…”