Cyclosporine-A induces endoplasmic reticulum stress and influences pro-apoptotic factors in human gingival fibroblasts

Cyclosporine-A (CsA) induces gingival overgrowth. Cyclosporine's anti-apoptotic activity in human gingival fibroblast is due to desensitization of mitochondrial permeability transition pore (MPTP) and augmentation of anti-apoptotic, Bcl2. Alternative mechanisms of apoptosis exist involving enzymes like calcium-dependent Calpain and signaling events related to apoptosis, like Glycogen synthase kinase 3 beta (GSK3 beta) and protein kinase A (PKA). Cyclosporine-A in renal tubular cells induces endoplasmic reticulum stress (ER stress) which has not been explored in gingival overgrowth. Hence, this study was carried out to assess the influence of Cyclosporine-on ER stress and on the alternate anti-apoptotic mechanisms. Human gingival fibroblasts were treated with CsA, and expression of ER stress markers, such as binding immunoglobulin protein and CCAAT/enhancer-binding protein homologous protein (CHOP), MPTP, and expression of Calpain & GSK3 beta/PKA were estimated. The results showed CsA-added fibroblast significantly increasing the expression of Endoplasmic reticulum stress markers. Contrary to usual ER stress outcome of apoptosis, we observed Cyclosporine's antiapoptotic action in spite of augmented ER stress markers. We conclude that CsA's independent action on different organelles may alter the conventional outcome of ER stress.