Aldo-Keto Reductases in the Eye
Shun Ping HuangPalla SuryanarayanaPhilip A. RuzyckiRoss Arjun VarmaTheresa M. HarterG. Bhanuprakash ReddyJ. Mark Petrash
27
Citation
19
Reference
10
Related Paper
Citation Trend
Abstract:
Aldose reductase (AKR1B1) is an NADPH-dependent aldo-keto reductase best known as the rate-limiting enzyme of the polyol pathway. Accelerated glucose metabolism through this pathway has been implicated in diabetic cataract and retinopathy. Some human tissues contain AKR1B1 as well as AKR1B10, a closely related member of the aldo-keto reductase gene superfamily. This opens the possibility that AKR1B10 may also contribute to diabetic complications. The goal of the current study was to characterize the expression profiles of AKR1B1 and AKR1B10 in the human eye. Using quantitative reverse transcriptase-PCR and immunohistochemical staining, we observed expression of both AKR genes in cornea, iris, ciliary body, lens, and retina. Expression of AKR1B1 was the highest in lens and retina, whereas AKR1B10 was the highest in cornea. Lenses from transgenic mice designed for overexpression of AKR1B10 were not significantly different from nontransgenic controls, although a significant number developed a focal defect in the anterior lens epithelium following 6 months of experimentally induced diabetes. However, lenses from AKR1B10 mice remained largely transparent following longterm diabetes. These results indicate that AKR1B1 and AKR1B10 may have different functional properties in the lens and suggest that AKR1B10 does not contribute to the pathogenesis of diabetic cataract in humans.Keywords:
Polyol pathway
Aldo-keto reductase
Aldo-keto reductase 1 member B1 (AKR1B1) is pathogenically involved in diabetic complications by driving glucose flux through polyol pathway; a variety of AKR1B1 inhibitors has been developed for the treatment of diabetic complications and a body of invaluable preclinical and clinical data have been collected through decades efforts. Recent studies have shown that some AKR1B1 inhibitors demonstrate strong inhibitory activity to aldo-keto reductase family 1 member B10 (AKR1B10), a protein identical to AKR1B1, in vitro and in cancer cells. AKR1B1 and AKR1B10 are overexpressed in human tumors, such as liver, breast, and lung cancer, and may play a critical role in the development and progression of cancer through carbonyl detoxification, retinoic acid homeostatic regulation, and lipid metabolic control, as well as the activation of tobacco smoke carcinogens. Therefore, AKR1B1 inhibitors may represent a novel class of antitumor agents; and the clinical data assembled in diabetic clinics would greatly assist the transition of these inhibitors to cancer clinics. This article summaries the current understanding of the expression and function of AKR1B1 and AKR1B10 in human cancers and reviews the patents and papers of AKR1B1 inhibitors. Authors opinions concerning the current and future development of AKR1B1 and/or AKR1B10-specific inhibitors are discussed.
Aldo-keto reductase
Polyol pathway
Aldehyde Reductase
Cite
Citations (42)
Aldose reductase (AR) is an NADPH-dependent reductase, which acts on a variety of hydrophilic as well as hydrophobic aldehydes. It is currently defined as the first enzyme in the so-called polyol pathway, in which glucose is transformed into sorbitol by AR and then to fructose by an NAD+-dependent dehydrogenase. An exaggerated flux of glucose through the polyol pathway (as can occur in diabetes) with the subsequent accumulation of sorbitol, was originally proposed as the basic event in the aethiology of secondary diabetic complications. For decades this has meant targeting the enzyme for a specific and strong inhibition. However, the ability of AR to reduce toxic alkenals and alkanals, which are products of oxidative stress, poses the question of whether AR might be better classified as a detoxifying enzyme, thus raising doubts as to the unequivocal advantages of inhibiting the enzyme. This paper provides evidence of the possibility for an effective intervention on AR activity through an intra-site differential inhibition. Examples of a new generation of aldose reductase "differential" inhibitors (ARDIs) are presented, which can preferentially inhibit the reduction of either hydrophilic or hydrophobic substrates. Some selected inhibitors are shown to preferentially inhibit enzyme activity on glucose or glyceraldehyde and 3-glutathionyl-4-hydroxy-nonanal, but are less effective in reducing 4-hydroxy-2-nonenal. We question the efficacy of D, L-glyceraldehyde, the substrate commonly used in in vitro inhibition AR studies, as an in vitro reference AR substrate when the aim of the investigation is to impair glucose reduction.
Polyol pathway
Aldehyde Reductase
Glyceraldehyde
Sorbitol dehydrogenase
Aldo-keto reductase
Cite
Citations (52)
Aldose reductase (AKR1B1) is an NADPH-dependent aldo-keto reductase best known as the rate-limiting enzyme of the polyol pathway. Accelerated glucose metabolism through this pathway has been implicated in diabetic cataract and retinopathy. Some human tissues contain AKR1B1 as well as AKR1B10, a closely related member of the aldo-keto reductase gene superfamily. This opens the possibility that AKR1B10 may also contribute to diabetic complications. The goal of the current study was to characterize the expression profiles of AKR1B1 and AKR1B10 in the human eye. Using quantitative reverse transcriptase-PCR and immunohistochemical staining, we observed expression of both AKR genes in cornea, iris, ciliary body, lens, and retina. Expression of AKR1B1 was the highest in lens and retina, whereas AKR1B10 was the highest in cornea. Lenses from transgenic mice designed for overexpression of AKR1B10 were not significantly different from nontransgenic controls, although a significant number developed a focal defect in the anterior lens epithelium following 6 months of experimentally induced diabetes. However, lenses from AKR1B10 mice remained largely transparent following longterm diabetes. These results indicate that AKR1B1 and AKR1B10 may have different functional properties in the lens and suggest that AKR1B10 does not contribute to the pathogenesis of diabetic cataract in humans.
Polyol pathway
Aldo-keto reductase
Cite
Citations (27)
Aldehyde Reductase
Polyol pathway
Aldo-keto reductase
Cite
Citations (15)
Aldose reductase (AR, ALR2) is a member of the aldo-keto reductase superfamily. It is the first and rate-limiting enzyme of the polyol pathway. AR plays an essential role in the development of diabetic complications. It is designated as the most legitimate target for managing diabetic complications. One of the key challenges to the successful development of target-specific AR inhibitors is target selectivity. In this research, target-specific drug-like ALR2 inhibito
Polyol pathway
Aldehyde Reductase
Aldo-keto reductase
Limiting
Drug candidate
Drug Development
Drug target
Cite
Citations (0)
Aldehyde Reductase
Polyol pathway
Sorbinil
Aldo-keto reductase
IC50
Docking (animal)
Cite
Citations (50)
Aldehyde Reductase
Polyol pathway
Aldo-keto reductase
Cite
Citations (57)
Increased flux of glucose via the polyol pathway, oxidative stress and ischaemia lead to the upregulation of the aldose reductase (AR), the key enzyme of the polyol pathway. This adversely affects the organism and can in part be reduced by inhibition of the enzyme.In this study, we examined the effect of the HMG-CoA-reductase inhibitor atorvastatin on the expression of aldose reductase (AR, AKR1B1), aldehyde reductase (AldR, AKR1A1) and small intestine reductase (SIR, AKR1B10) in human umbilical vein endothelial cells (HUVEC) and human proximal tubular epithelial cells (PTEC) by RT-PCR.In HUVEC, atorvastatin reduces the expression of aldehyde reductase and aldose reductase compared with control medium (-20% and -12% respectively, P < 0.05), while small intestine reductase is not expressed. In PTEC no regulation of aldehyde reductase and aldose reductase by atorvastatin could be measured, while the expression of small intestine reductase was reduced by 37% compared with control medium (P < 0.05). The reduction observed was not abolished by the addition of mevalonic acid.The reduction of members of the aldo-keto-reductase family by atorvastatin is a novel way to influence the polyol pathway and a new pleiotropic effect of atorvastatin.
Aldehyde Reductase
Polyol pathway
Sorbinil
Aldo-keto reductase
Cite
Citations (7)
Polyol pathway
Aldo-keto reductase
Monosaccharide
Cite
Citations (2)
Polyol pathway
Aldehyde Reductase
Aldo-keto reductase
Cite
Citations (191)