Sumin Gu1, Sondip Biswas2, Luis Rodriguez1, Zhen Li1, Yuting Li1, Manuel A Riquelme1, Wen Shi1,3, Ke Wang1, Thomas W White4, Matthew Reilly5, Woo-Kuen Lo2, Jean X Jiang1. 1. Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States. 2. Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, United States. 3. The Second Xiangya Hospital, Central South University, Changsha, China. 4. Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, United States. 5. Department of Biomedical Engineering, The Ohio State University College of Engineering, Columbus, Ohio, United States.
Abstract
Purpose: Connexins and aquaporins play essential roles in maintaining lens homeostasis and transparency and there is a close physical and functional relationship between these two proteins. Aquaporin 0 (AQP0), in addition to its role in water transport in the lens, acts as a cell-cell adhesion molecule. Recently, we showed a new role of connexin (Cx) 50 in mediating cell-cell adhesion. However, the cooperative roles of these two proteins in the lens in vivo have not been reported. Methods: We generated an AQP0/Cx50 double knockout (dKO) mouse model. Light, fluorescence, transmission thin section, and freeze-fracture electron microscopy, as well as wheat germ agglutinin and phalloidin labeling were used to evaluate lens structure. Mechanical properties of lenses were determined by mechanical compression testing. Results: DKO mice exhibited small eyes and lenses with severe cataracts, along with lens posterior defects, including posterior capsule rupture. The dKO mouse lenses had severe structural disruption associated with increased spaces between lens fiber cells when compared with wild-type lenses or lenses deficient in either Cx50 or AQP0. DKO mice also exhibited greater reduction in lens size compared with Cx50 KO mice. Gap-junction plaque size was greatly decreased in cortical fiber cells in dKO mice. Moreover, lens stiffness and elasticity were completely diminished, exhibiting a gelatinous texture in adult dKO mice. Conclusions: This novel mouse model reveals that Cx50 and AQP0 play an important role in mediating cell-cell adhesion function in the lens fiber cells and their deficiency impairs lens fiber organization, integrity, mechanical properties, and lens development.
Purpose: Connexins and aquaporins play essential roles in maintaining lens homeostasis and transparency and there is a close physical and functional relationship between these two proteins. Aquaporin 0 (AQP0), in addition to its role in water transport in the lens, acts as a cell-cell adhesion molecule. Recently, we showed a new role of connexin (Cx) 50 in mediating cell-cell adhesion. However, the cooperative roles of these two proteins in the lens in vivo have not been reported. Methods: We generated an AQP0/Cx50 double knockout (dKO) mouse model. Light, fluorescence, transmission thin section, and freeze-fracture electron microscopy, as well as wheat germ agglutinin and phalloidin labeling were used to evaluate lens structure. Mechanical properties of lenses were determined by mechanical compression testing. Results: DKO mice exhibited small eyes and lenses with severe cataracts, along with lens posterior defects, including posterior capsule rupture. The dKO mouse lenses had severe structural disruption associated with increased spaces between lens fiber cells when compared with wild-type lenses or lenses deficient in either Cx50 or AQP0. DKO mice also exhibited greater reduction in lens size compared with Cx50 KO mice. Gap-junction plaque size was greatly decreased in cortical fiber cells in dKO mice. Moreover, lens stiffness and elasticity were completely diminished, exhibiting a gelatinous texture in adult dKO mice. Conclusions: This novel mouse model reveals that Cx50 and AQP0 play an important role in mediating cell-cell adhesion function in the lens fiber cells and their deficiency impairs lens fiber organization, integrity, mechanical properties, and lens development.
Authors: Guido A Zampighi; Michael Kreman; Salvatore Lanzavecchia; Eric Turk; Sepehr Eskandari; Lorenzo Zampighi; Ernest M Wright Journal: J Mol Biol Date: 2003-01-03 Impact factor: 5.469
Authors: A Shiels; S Bassnett; K Varadaraj; R Mathias; K Al-Ghoul; J Kuszak; D Donoviel; S Lilleberg; G Friedrich; B Zambrowicz Journal: Physiol Genomics Date: 2001-12-21 Impact factor: 3.107
Authors: Francisco J Martinez-Wittinghan; Caterina Sellitto; Thomas W White; Richard T Mathias; David Paul; Daniel A Goodenough Journal: Invest Ophthalmol Vis Sci Date: 2004-10 Impact factor: 4.799
Authors: Susanna Törnroth-Horsefield; Clara Chivasso; Helin Strandberg; Claudia D'Agostino; Carla V T O'Neale; Kevin L Schey; Christine Delporte Journal: Int J Mol Sci Date: 2022-08-25 Impact factor: 6.208
Authors: Jessica B Martin; Kenneth Herman; Nathalie S Houssin; Wade Rich; Matthew A Reilly; Timothy F Plageman Journal: Front Cell Dev Biol Date: 2022-07-06