Increase of Claudin-5, ICAM-1 and eNOS expressions in human brain endothelial cells by ammonium chloride

Abstract

Abstract Objectives Lysosomal dysfunction could lead to a failure in the degradation process of waste materials, especially for the elimination of aggregated, misfolded and senescence proteins or organelles. Human brain endothelial cells (HBECs) are a part of the blood-brain barrier and any disruption of lysosomal functions could affect the cellular functions of the HBECs. Protein expression studies on the cells could give an insight to associate lysosomal dysfunction on HBECs homeostasis. The aim of this study was to measure the cellular changes via the expression of several proteins such as Claudin-5, which is a tight junction protein; intracellular adhesion molecule 1 (ICAM-1), an inflammatory marker and endothelial nitric oxide synthase (eNOS), which provides nitric oxide (NO) for vasodilation. These components are important in maintaining homeostasis as the imbalance could lead to endothelial impairment linked brain related disorders such as neurodegenerative disease. Methods HBECs were treated with 10 mM ammonium chloride, which is a lysosome inhibitor for 1 h. The protein lysates were collected and subjected for ICAM-1 and Claudin-5 measurement by capillary immunoassay instrument, while eNOS by ELISA. Results Claudin-5 and ICAM-1 expression significantly increased (p<0.05). The ELISA results showed eNOS increment (p<0.001) compared to control. Lysosome inhibitor could be associated with accumulation of organelles that can stimulates inflammation and initial cellular responses. Conclusions Inhibition of lysosome by the inhibitor increases protein expressions related with endothelial function.