Substrate elasticity as biomechanical modulator of tissue homeostatic parameters in corneal keratinocytes

This study aimed at identifying putative modulations of tissue homeostatic parameters in corneal keratinocytes in response to biomechanical cues as basis for innovative cornea biomechanical-tailored biomaterials. Since cornea epithelial biomechanics is already described for contacts on nanostructures, we herein analyzed cell response to mechanical substrate elasticity. Therefore, corneal keratinocytes were established on physiologically-relevant elastic substrates of 40 kPa, 130 kPa but also on non-physiological stiff substrates of 1.74 MPa for 3 days. qPCR revealed that changes in gene expression were only marginal between 40 kPa and 130 kPa, while significant modulations were seen on 1.74 MPa substrates for most tissue-innate biomarkers under study. Gene expression fairly coincided with the protein, with differentiation progression biomarkers involucrin and fillagrin being already significantly increased between elasticities of 40 kPa and 130 kPa. Regarding focal adhesions, reinforcement was seen for ß1 integrin and phospho- p125FAK between 40 kPa and 130 kPa, while from 130 kPa to 1.74 MPa actin redistributed and phospho-p125FAK was strikingly up-regulated. These findings suggest elasticity dependence for differentiation progression and focal adhesion dynamics of corneal keratinocytes, supporting the concept of biomechanics governed regulation of tissue homeostasis. Moreover, this concept in turn can be translated into prospective cornea-tailored biomaterials for therapeutic approaches in ophthalmology.