Effects of transient plasma membrane disruptions on control and diabetic corneal cells.

Transient plasma membrane disruptions (TPMDs) are mechanically induced membrane injuries that initiate cellular repair and signaling responses. Although TPMDs have recently been identified in corneal cells, their physiological consequences and the effects of diabetes on TPMD-mediated responses remain poorly understood. The aim of this study was to examine the effects of TPMDs on calcium signaling, apoptosis, proliferation, and collagen expression in corneal epithelial and stromal cells and determined how these responses are influenced by diabetes. TPMDs were induced in cultured human corneal epithelial cells (HCECs) and stromal cells (HCSCs) and in ex vivo mouse corneas using laser-mediated membrane disruption or glass bead rolling. TPMD-induced calcium wave (TPMD Ca++Wv) propagation, apoptosis, proliferation, and collagen protein expression were quantified in non-diabetic and diabetic cells. Diabetes significantly altered TPMD-induced calcium signaling, reducing TPMD Ca++Wv responses in diabetic HCSCs and mouse corneal epithelial cells while enhancing TPMD Ca++Wv propagation in diabetic mouse corneal stromal cells. TPMDs increased apoptosis in most corneal cell types and stimulated proliferation in HCECs and HCSCs. TPMDs also altered stromal collagen expression, increasing collagen levels in non-diabetic cells but reducing collagen expression in diabetic cells. These findings demonstrate that TPMDs regulate multiple processes involved in corneal homeostasis and that diabetes substantially modifies these responses, potentially contributing to diabetic keratopathy.