Vitamin A derivative all-trans-retinoic acid regulates the expression of over 530 different genes. Consequently, the levels of retinoic acid during embryogenesis are controlled in a spatially and temporally precise manner. However, the molecular mechanisms underlying this regulation are not yet fully understood. The long-term objective of this project is to determine the role of short-chain dehydrogenases/reductases (SDRs) in the regulation of retinoic acid biosynthesis in health and disease. Recently, we have identified a new member of the SDR superfamily of proteins in frogs, rdhe 2, that is highly active as an all-trans-retinol dehydrogenase and is critical for embryonic development in Xenopus laevis. Importantly, there appears to be a functional equivalent of the frog rdhe2 in mammals, which exhibits an all-trans-retinol dehydrogenase activity and is expressed during early embryonic development. We propose that this novel enzyme, named RDH-E2S, is essential for retinoic acid biosynthesis in mammals during embryogenesis and, possibly, in adulthood. To test this hypothesis, we will characterize the catalytic properties of mammalian RDH-E2S and determine its contribution to retinoic acid biosynthesis in vivo using genetically modified mouse model (Specific Aim 1). Our preliminary studies indicate that silencing of retina short-chain dehydrogenase/reductase 1 (retSDR1) gene expression in human cells results in significant increase in the levels of both retinoic acid and retinaldehyde, which translates into dramatic upregulation of retinoic acid-responsive genes. This finding suggests that the rate of retinoic acid biosynthesis is determined by the relative activities of retinol dehydrogenases and retinaldehyde reductases, which together control the levels of retinoic acid precursor, retinaldehyde. To test this hypothesis, we propose to characterize the catalytic properties of retSDR1 and to determine its role in the regulation of retinoic acid levels in vivo using genetically modified mice, human skin organ culture, and Xenopus laevis in vitro model of early embryonic development (Specific Aim 2). These studies will fill the gaps in our understanding of the mechanisms responsible for the maintenance of retinoic acid homeostasis by providing new information regarding the roles of potentially important components of the retinoid regulatory system. The results of these studies will be important for understanding the pathophysiology of disorders associated with disruptions of retinoid homeostasis, such as fetal alcohol syndrome, alcoholic liver disease, carcinogenesis, and diabetes.
All-trans-retinoic acid is the most potent of the biologically active derivatives of vitamin A, which regulates the expression of over 530 different genes. We have identified two members of the short-chain dehydrogenase/reductase superfamily of proteins that may be very important for the biosynthesis and regulation of retinoic acid levels during development as well as adulthood. The results of the proposed studies will provide information important for understanding the pathophysiology of disorders associated with disruptions of retinoid homeostasis, such as fetal alcohol syndrome, alcoholic liver disease, carcinogenesis, and diabetes.
|Adams, Mark K; Belyaeva, Olga V; Wu, Lizhi et al. (2014) The retinaldehyde reductase activity of DHRS3 is reciprocally activated by retinol dehydrogenase 10 to control retinoid homeostasis. J Biol Chem 289:14868-80|
|Belyaeva, Olga V; Lee, Seung-Ah; Adams, Mark K et al. (2012) Short chain dehydrogenase/reductase rdhe2 is a novel retinol dehydrogenase essential for frog embryonic development. J Biol Chem 287:9061-71|
|Lee, Seung-Ah; Belyaeva, Olga V; Wu, Lizhi et al. (2011) Retinol dehydrogenase 10 but not retinol/sterol dehydrogenase(s) regulates the expression of retinoic acid-responsive genes in human transgenic skin raft culture. J Biol Chem 286:13550-60|
|Lee, Seung-Ah; Belyaeva, Olga V; Kedishvili, Natalia Y (2011) Evidence that proteosome inhibitors and chemical chaperones can rescue the activity of retinol dehydrogenase 12 mutant T49M. Chem Biol Interact 191:55-9|
|Lee, Seung-Ah; Belyaeva, Olga V; Kedishvili, Natalia Y (2010) Disease-associated variants of microsomal retinol dehydrogenase 12 (RDH12) are degraded at mutant-specific rates. FEBS Lett 584:507-10|
|Lee, Seung-Ah; Belyaeva, Olga V; Kedishvili, Natalia Y (2009) Biochemical characterization of human epidermal retinol dehydrogenase 2. Chem Biol Interact 178:182-7|
|Belyaeva, Olga V; Lee, Seung-Ah; Kolupaev, Oleg V et al. (2009) Identification and characterization of retinoid-active short-chain dehydrogenases/reductases in Drosophila melanogaster. Biochim Biophys Acta 1790:1266-73|
|Wang, Lan; Li, Chuan-Ming; Rudolf, Martin et al. (2009) Lipoprotein particles of intraocular origin in human Bruch membrane: an unusual lipid profile. Invest Ophthalmol Vis Sci 50:870-7|
|Belyaeva, Olga V; Johnson, Mary P; Kedishvili, Natalia Y (2008) Kinetic analysis of human enzyme RDH10 defines the characteristics of a physiologically relevant retinol dehydrogenase. J Biol Chem 283:20299-308|
|Lee, Seung-Ah; Belyaeva, Olga V; Kedishvili, Natalia Y (2008) Effect of lipid peroxidation products on the activity of human retinol dehydrogenase 12 (RDH12) and retinoid metabolism. Biochim Biophys Acta 1782:421-5|
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