Abnormal Aquaporin 5 C-terminal Binding Proteins in a Mouse Model of Sjögren’s Syndrome

Abstract

Abstract: : Purpose: Distribution of aquaporin 5 (AQP5) is altered in the lacrimal glands of patients with Sjögren’s syndrome (SS). The purpose of this study was to determine whether AQP5 C-terminal binding proteins in SS caused the abnormal distribution of AQP5 in the apical membrane of lacrimal gland. Methods: The lacrimal glands of 8-week-old male NOD/Shi Jci mice (n=25) used as SS model and male Jcl:ICR mice (n=25) as control of NOD/Shi Jci mice were removed, and homogenized. These homogenates were delivered into through the affinity columns conjugated with synthetic AQP5 C-terminal peptide. The elutions of AQP5 C-terminal binding proteins were analyzed by electrophoresis and protein dye techniques. Results: The pattern of proteins between 59 and 92 kDa in NOD/Shi Jci mice showed a minor difference to that in Jcl:ICR mice. Additionally, the specific proteins of 21 and 17 kDa appeared in NOD/Shi Jci and Jcl:ICR mice, respectively. Conclusions: These detected AQP5 C-terminal binding proteins may perform the stability or instability of AQP5 located in the apical membrane of lacrimal gland. This suggests that abnormal distribution of AQP5 in SS might be related to abnormal AQP5 C-terminal binding proteins.

Keywords: lacrimal gland • cornea: tears/tear film/dry eye • protein purification and characterization