Advanced Glycation End Products and Receptor (RAGE) Promote Wound Healing of Human Corneal Epithelial Cells

Abstract

PURPOSE.We used a human corneal epithelial cell (HCE) line to determine the involvement of the advanced glycation end products (AGEs) / receptor for AGEs (RAGE) couple in corneal epithelium wound healing. METHODS.After wounding, HCE cells were exposed to two major RAGE ligands (HMGB1 and AGEs), and wound healing was evaluated using the in vitro scratch assay. Following wound healing, the HCE cells were used to study the influence of the RAGE ligands on HCE proliferation, invasion, and migration. Activation of the nuclear factor (NF)-κB signaling pathway by the AGEs/RAGE couple was tested using a luciferase reporter assay. Functional transcriptional regulation by this pathway was confirmed by quantification of expression of the connexin 43 target gene. For each experiment, specific RAGE involvement was confirmed by small interfering RNA treatments. RESULTS.AGEs treatment at a dose of 100 μg/mL significantly improved the wound healing process in a RAGE-dependent manner by promoting cell migration, whereas HMGB1 had no effect. No significant influence of the AGEs/RAGE couple was observed on cell proliferation and invasion. However, this treatment induced an early activation of the NF-κB pathway and positively regulated the expression of the target gene, connexin 43, at both the mRNA and protein levels. CONCLUSIONS.Our results demonstrate that the RAGE pathway is activated by AGEs treatment and is involved in the promotion of corneal epithelial wound healing. This positive action is observed only during the early stages of wound healing, as illustrated by the quick activation of the NF-κB pathway and induction of connexin 43 expression.

Dysregulation of Receptor for Advanced Glycation End Products (RAGE) Expression as a Biomarker of Keratoconus

“…A variety of tissues and cells express this pattern recognition receptor: vascular endothelial, bronchial, and pulmonary cells, vascular smooth muscle cells, neurons, and many others [ 29 , 31 ]. The involvement of the RAGE pathway in corneal epithelial wound healing, as well as diseases of conjunctiva and retina and trabecular meshwork, has been demonstrated previously [ 35 – 41 , 43 ]. The activation of fl-RAGE stimulates NF- κ B, a transcription factor residing at the inactive state in the cytosol of cells, which can modulate the expression of proinflammatory cytokines, vasoconstrictive and prothrombotic products, and adhesion molecules [ 29 ].…”

“…Expression of RAGE, described in several human tissues, is upregulated in response to its natural and historical ligand, i.e., advanced glycation end products (AGEs), but also HMGB1 and S100 proteins that are well-known in aseptic inflammation and oxidative stress of diabetes patients, atherosclerosis, pulmonary and auto-immune diseases, cancer, and chronic neurodegenerative like Alzheimer's disease [ 30 – 34 ]. In ophthalmology, we recently demonstrated the implications of RAGE in the first steps of corneal epithelial wound healing [ 35 ].…”

The receptor for advanced glycation end-products enhances lung epithelial wound repair: An in vitro study

“…There is growing evidence supporting the involvement of RAGE pathway in mechanisms of cell and tissue repair after injury. Indeed, the AGE/RAGE axis promotes wound healing of human corneal epithelial cells [36] and HMGB1/RAGE axis promotes keratinocyte healing in vitro [15], with improved healing of diabetic human and mouse skin [37]. In addition, HMGB1 improves scratch wound healing of human bronchial epithelial cells via toll-like receptor (TLR)-4 and RAGE-mediated increase in extracellular matrix synthesis and modulation of cell-matrix adhesion [31].…”

RAGE against the Machine: Can Increasing Our Understanding of RAGE Help Us to Battle SARS-CoV-2 Infection in Pregnancy?

“…This genotype is characterized by lower sRAGE levels and higher risk factors for CVD, which has implicated it in diabetes and autoimmune diseases, such as Kawasaki disease [ 25 ]. Thus, abnormal upregulation and sRAGE activation are indicative of disease development and inflammatory and immune responses in the body [ 28 , 103 , 152 , 153 ]. Generally, increased levels of membrane-bound RAGE are associated with disease pathogenesis/injury because the ligands bound to fl-RAGE are able to transduce that signal intracellularly and stimulate the nuclear translocation of NF-κB, thus producing inflammation.…”