TY - JOUR
T1 - Aldose reductase-mediated induction of epithelium-to-mesenchymal transition (EMT) in lens
AU - Zablocki, Gregory J.
AU - Ruzycki, Philip A.
AU - Overturf, Michelle A.
AU - Palla, Suryanarayana
AU - Reddy, G. Bhanuprakesh
AU - Petrash, J. Mark
N1 - Funding Information:
Funding for this project was provided by grant EY005856 from the National Eye Institute (to JMP) and by a Boyscast Fellowship (to S. Palla) from the Ministry of Science and Technology of India. The authors gratefully acknowledge the assistance of Mike Casey, Theresa Harter, Belinda McMahan, and Sue Penrose in various aspects of the project. Dr. Lixing Reneker (University of Missouri, Columbia) generously provided the α/δ promoter transgene construct used in these studies. The authors wish to dedicate this paper to the memory of Professor Henry Weiner, whose tireless efforts to organize a biennial research conference devoted to carbonyl metabolism helped to launch the careers of countless scientists.
PY - 2011/5/30
Y1 - 2011/5/30
N2 - Cataract is a key factor in the morbidity associated with diabetes. While the pathogenesis of diabetic cataract formation is poorly understood, previous research has identified aldose reductase (ALR2) as a key player. To elucidate a potential role for this enzyme in diabetic cataract formation, we created a series of transgenic mice designed for expression of human ALR2 (AKR1B1) in epithelial and outer cortical fiber cells of the lens. One of the founder lines, designated PAR39, developed an early onset cataract that involved formation of a plaque of cells at the anterior aspect of the lens. These cells appear to separate from the anterior epithelium and undergo a dramatic change that is reminiscent of the epithelial to mesenchymal transition (EMT). We characterized this phenotype in the PAR39 strain by examining rates of cell proliferation and by immunostaining for markers of EMT. Incorporation of the thymidine analog bromodeoxyuridine (BrdU) was used to estimate cell proliferation in two functional areas of the lens epithelium: the mitotically active germinative zone (GZ) and the less proliferative center zone (CZ). Staining cell nuclei with diamido 4′,6-diamidino-2-phenylindole (DAPI) was used to establish a total cell count in the demarcated areas. Lens epithelium in PAR39 transgenic mice demonstrated a decrease in the percentage of BrdU/DAPI staining within the GZ as compared to nontransgenic littermate controls (8.1% vs. 10.9%). A similar decrease in BrdU/DAPI was observed in the CZ (0.6% compared to 3.3%). However, cell density was greater within the GZ of PAR39 mice as compared with nontransgenic controls, while it was not significantly different in the CZ among the two groups. Furthermore, cells associated with the epithelial plaque did not stain positive for BrdU, but were strongly positive for alpha-smooth muscle actin, a classical marker for EMT. These findings suggest that ALR2 over-expression is associated with an alteration in the balance between proliferation and apoptosis of epithelial cells in the mouse lens, and that cells associated with epithelial plaques in the PAR39 lens have features in common with cells undergoing EMT.
AB - Cataract is a key factor in the morbidity associated with diabetes. While the pathogenesis of diabetic cataract formation is poorly understood, previous research has identified aldose reductase (ALR2) as a key player. To elucidate a potential role for this enzyme in diabetic cataract formation, we created a series of transgenic mice designed for expression of human ALR2 (AKR1B1) in epithelial and outer cortical fiber cells of the lens. One of the founder lines, designated PAR39, developed an early onset cataract that involved formation of a plaque of cells at the anterior aspect of the lens. These cells appear to separate from the anterior epithelium and undergo a dramatic change that is reminiscent of the epithelial to mesenchymal transition (EMT). We characterized this phenotype in the PAR39 strain by examining rates of cell proliferation and by immunostaining for markers of EMT. Incorporation of the thymidine analog bromodeoxyuridine (BrdU) was used to estimate cell proliferation in two functional areas of the lens epithelium: the mitotically active germinative zone (GZ) and the less proliferative center zone (CZ). Staining cell nuclei with diamido 4′,6-diamidino-2-phenylindole (DAPI) was used to establish a total cell count in the demarcated areas. Lens epithelium in PAR39 transgenic mice demonstrated a decrease in the percentage of BrdU/DAPI staining within the GZ as compared to nontransgenic littermate controls (8.1% vs. 10.9%). A similar decrease in BrdU/DAPI was observed in the CZ (0.6% compared to 3.3%). However, cell density was greater within the GZ of PAR39 mice as compared with nontransgenic controls, while it was not significantly different in the CZ among the two groups. Furthermore, cells associated with the epithelial plaque did not stain positive for BrdU, but were strongly positive for alpha-smooth muscle actin, a classical marker for EMT. These findings suggest that ALR2 over-expression is associated with an alteration in the balance between proliferation and apoptosis of epithelial cells in the mouse lens, and that cells associated with epithelial plaques in the PAR39 lens have features in common with cells undergoing EMT.
KW - Aldo-keto reductase
KW - Cataract
KW - Diabetes
KW - EMT
KW - Epithelial-to-mesenchymal transition
UR - http://www.scopus.com/inward/record.url?scp=79957576582&partnerID=8YFLogxK
U2 - 10.1016/j.cbi.2011.02.005
DO - 10.1016/j.cbi.2011.02.005
M3 - Article
C2 - 21329682
AN - SCOPUS:79957576582
SN - 0009-2797
VL - 191
SP - 351
EP - 356
JO - Chemico-Biological Interactions
JF - Chemico-Biological Interactions
IS - 1-3
ER -