Galectin-3 enhances extracellular matrix associations and wound healing in monkey corneal epithelium

Abstract

Poor healing of epithelial wounds in cornea is a major clinical problem, leading to persistent epithelial defects and ulceration. The primary cause is poor cell migration over the wound. Carbohydrate-binding protein galectin-3 binds to extracellular matrixes (ECMs) and promotes lamellipodia formation by cross-linking to α3 integrin. Recombinant galectin-3 also facilitates wound healing in the rodent cornea. The purposes of the present experiments were to: (1) establish epithelial wound healing models in monkey corneal explant culture, the models more relevant to human, (2) evaluate the healing effect of galectin-3 in our models, and (3) determine if galectin-3 enhances cell adhesion by interacting with ECMs on corneal surface and their ligand integrins. Monkey corneas with central wounds produced by sodium hydroxide (NaOH) or n-heptanol were incubated with or without recombinant galectin-3. The defected area was stained with sodium fluorescein. Primary isolated corneal epithelial cells from monkey were cultured with or without galectin-3 on plates coated with ECMs or integrins, and the number of adhering cells was counted. Galectin-3 expression in various eye tissues was visualized by immunoblotting. NaOH caused loss of epithelial cells and basement membrane. n-Heptanol removed epithelial cells, but the basement membrane was retained. These corneal defects spontaneously became smaller in a time-dependent manner. Exogenous galectin-3 enhanced wound healing in both NaOH and n-heptanol models. Galectin-3 also enhanced cell adhesion onto the major ECMs found in the basement and Bowman’s membranes and onto integrins. Relatively high levels of galectin-3 were detected in corneal and conjunctival epithelium, but tear fluid contained negligible galactin-3. These results suggested that the enhanced binding of epithelial cells to ECMs and integrins caused by galectin-3 might promote cell migration over wounded corneal surfaces. Since tear fluid contained relatively low levels of galectin-3, exogenous galectin-3 may be a beneficial drug to enhance re-epithelialization in human corneal diseases.

Histological investigation of human glaucomatous eyes: Extracellular fibrotic changes and galectin 3 expression in the trabecular meshwork and optic nerve head

“…The role of Gal3 in promoting fibrosis is an area of active research, and Gal3 has been associated with increased collagen deposition in hepatic, renal, pulmonary and cardiac fibrosis (Li et al, 2014). The ability of galectins to bind to ECM components such as fibronectin, laminins, integrins, and collagens has been reported (Sasaki et al, 1998;Fujii et al, 2015). Gal3 mediated crosslinking of epidermal growth factor and transforming growth factors receptors (Partridge et al, 2004) delayed of receptor endocytosis, thereby maintaining signaling activation.…”

“…The optic nerve and TM express Gal3 in animals (Argueso and Panjwani, 2011;Davis et al, 2014). Extracellular proteins, such as collagens, integrins, and fibronectin, have been shown to bind to Gal3 in the corneal epithelium (Fujii et al, 2015). In TM cells, galectins have been shown to modulate adhesion and cytoskeletal arrangement through their interactions with beta 1 integrin and induction of Rho signaling (Diskin et al, 2009).…”

Evaluation of galectin-1 and galectin-3 as prospective biomarkers in keratoconus

“…In relation to the cornea, administration of recombinant Gal-1 decreases the corneal opacity and lesion scores, influx of inflammatory cells and cytokine release induced by Herpes simplex and Pseudomonas aeruginosa corneal infections in mice, reinforcing its anti-inflammatory role 16 17. However, Gal-3 plays an important role in the corneal re-epithelialisation process demonstrated by in vivo and in vitro corneal healing assays performed in mice18 and monkeys 19. In addition, administration of exogenous Gal-3 in the human keratocyte culture induces MMP-9 release through activation of the CD147 receptor (inductor of the MMP expression) and epithelial disorganisation through the disruption of occlusive junctions 20.…”

Developing a ‘thick skin’: a paradoxical role for mechanical tension in maintaining epidermal integrity?

“…Interestingly, in both animals and plants an important role for these highly modified supra-cellular matrices in maintaining cell layer integrity has been uncovered. For example, in wounded animal epithelia, molecular signals located on the basement membrane are crucial for guiding the migration of cells to replace damaged cells (Fujii et al, 2015). In plants, as discussed above it is clear that the outer cell wall of the epidermis, which is inherited when anticlinal divisions occur, is a vital repository of positional information necessary for the maintenance of epidermal cell identity (ten Hove et al, 2015).…”