Natalia Y Kedishvili

University of Alabama at Birmingham, Birmingham, Alabama, United States

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Publications (61)209.6 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: (2E,4E,6Z,8Z)-8-(3',4'-Dihydro-1'(2H)-naphthalen-1'-ylidene)-3,7-dimethyl-2,3,6-octatrienoinic acid (UAB30) is currently undergoing clinical evaluation as a novel cancer prevention agent. In efforts to develop even more highly potent rexinoids that prevent breast cancer without toxicity, we further explore here the structure-activity relationship of two separate classes of rexinoids. UAB30 belongs to the class II rexinoids and possesses a 9Z-tetraenoic acid chain bonded to a tetralone ring, whereas the class I rexinoids contain the same 9Z-tetraenoic acid chain bonded to a di-substituted cyclohexenyl ring. Among the twelve Class I and Class II rexinoids evaluated, the Class I rexinoid 11 is most effective in preventing breast cancers in an in-vivo rat model alone or in combination with tamoxifen. Rexinoid 11 also reduces the size of established tumors and exhibits a therapeutic effect. However, 11 induces hypertriglyceridemia at its effective dose. On the other hand rexinoid 10 does not increase triglyceride levels while being effective in the in vivo chemoprevention assay. X-ray studies of four rexinoids bound to the ligand binding domain of the retinoid X receptor reveal key structural aspects that enhance potency as well as those that enhance the synthesis of lipids.
    Journal of Medicinal Chemistry 09/2015; DOI:10.1021/acs.jmedchem.5b00829 · 5.45 Impact Factor
  • Olga V. Belyaeva · Chenbei Chang · Michael C. Berlett · Natalia Y. Kedishvili
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    ABSTRACT: Vertebrate enzymes that belong to the 16C family of short-chain dehydrogenases/reductases (SDR16C) were shown to play an essential role in the control of retinoic acid (RA) levels during development. To trace the evolution of enzymatic function of SDR16C family, and to examine the origins of the pathway for RA biosynthesis from vitamin A, we identified putative SDR16C enzymes through the extensive search of available genome sequencing data in a subset of species representing major metazoan phyla. The phylogenetic analysis revealed that enzymes from protostome, non-chordate deuterostome and invertebrate chordate species are found in three clades of SDR16C family containing retinoid active enzymes, which are retinol dehydrogenase 10 (RDH10), retinol dehydrogenases E2 (RDHE2) and RDHE2-similar, and dehydrogenase reductase (SDR family) member 3 (DHRS3). For the initial functional analysis, we cloned RDH10- and RDHE2-related enzymes from the early developmental stages of a non-chordate deuterostome, green sea urchin Lytechinus variegatus, and an invertebrate chordate, sea squirt Ciona intestinalis. In situ hybridization revealed that these proteins are expressed in a pattern relevant to development, while assays performed on proteins expressed in mammalian cell culture showed that they possess retinol-oxidizing activity as their vertebrate homologs. The existence of invertebrate homologs of DHRS3 was inferred from the analysis of phylogeny and cofactor-binding residues characteristic of preference for NADP(H). The presence of invertebrate homologs in the DHRS3 group of SDR16C is interesting in light of the complex mutually activating interaction, which we have recently described for human RDH10 and DHRS3 enzymes. Further functional analysis of these homologs will establish whether this interaction evolved to control retinoid homeostasis only in vertebrates, or is also conserved in pre-vertebrates.
    Chemico-Biological Interactions 11/2014; 234. DOI:10.1016/j.cbi.2014.10.026 · 2.58 Impact Factor
  • Mark K Adams · Olga V Belyaeva · Lizhi Wu · Natalia Y Kedishvili
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    ABSTRACT: The retinoic acid inducible Dehydrogenase Reductase 3 (DHRS3) is thought to function as a retinaldehyde reductase that controls the levels of all trans retinaldehyde, the immediate precursor for bioactive all trans retinoic acid. However, the weak catalytic activity of DHRS3 and the lack of changes in retinaldehyde conversion to retinol and retinoic acid in the cells overexpressing DHRS3 undermine its role as a physiologically important all trans retinaldehyde reductase. This study demonstrates that DHRS3 requires the presence of Retinol Dehydrogenase 10 (RDH10) in order to display its full catalytic activity. The RDH10 activated DHRS3 acts as a robust high affinity all trans retinaldehyde specific reductase that effectively converts retinaldehyde back to retinol, decreasing the rate of retinoic acid biosynthesis. In turn, the retinol dehydrogenase activity of RDH10 is reciprocally activated by DHRS3. At E13.5, DHRS3-null embryos have ~4 fold lower levels of retinol and retinyl esters, but only slightly elevated levels of retinoic acid. The membrane associated retinaldehyde reductase and retinol dehydrogenase activities are decreased by ~4 fold and ~2 fold, respectively, in Dhrs3(-/-) embryos, and Dhrs3(-/-) mouse embryonic fibroblasts exhibit reduced metabolism of both retinaldehyde and retinol. Neither RDH10 nor DHRS3 has to be itself catalytically active to activate each other. The transcripts encoding DHRS3 and RDH10 are colocalized at least in some tissues during development. The mutually activating interaction between the two related proteins may represent a highly sensitive and conserved mechanism for precise control over the rate of retinoic acid biosynthesis.
    Journal of Biological Chemistry 04/2014; 289(21). DOI:10.1074/jbc.M114.552257 · 4.57 Impact Factor
  • Natalia Y Kedishvili
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    ABSTRACT: All-trans-retinoic acid is the most biologically potent derivative of vitamin A that regulates numerous physiological processes. The concentration of retinoic acid in the cells is tightly regulated, but the exact mechanisms responsible for this regulation are not yet completely understood, largely because the enzymes involved in the biosynthesis of retinoic acid have not yet been fully defined. Recent studies using in vitro and in vivo models suggest that several members of the short-chain dehydrogenase/reductase superfamily of proteins are essential for retinoic acid biosynthesis and the maintenance of retinoic acid homeostasis. However, the exact roles of some of these recently identified enzymes are yet to be characterized. The properties of the known contributors to retinoid metabolism have now been better defined and allow for more detailed understanding of their interactions with retinoid binding proteins and other retinoid enzymes. At the same time, further studies are needed to clarify the interactions between the cytoplasmic and membrane-bound proteins involved in the processing of hydrophobic retinoid metabolites. This review summarizes the current state of knowledge on the roles of various biosynthetic and catabolic enzymes in the regulation of retinoic acid homeostasis and outlines the remaining questions in the field.
    The Journal of Lipid Research 04/2013; 54(7). DOI:10.1194/jlr.R037028 · 4.42 Impact Factor
  • Olga V Belyaeva · Seung-Ah Lee · Mark K Adams · Chenbei Chang · Natalia Y Kedishvili
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    ABSTRACT: The enzymes responsible for the rate-limiting step in retinoic acid biosynthesis, the oxidation of retinol to retinaldehyde, during embryogenesis and in adulthood have not been fully defined. Here, we report that a novel member of the short chain dehydrogenase/reductase superfamily, frog sdr16c5, acts as a highly active retinol dehydrogenase (rdhe2) that promotes retinoic acid biosynthesis when expressed in mammalian cells. In vivo assays of rdhe2 function show that overexpression of rdhe2 in frog embryos leads to posteriorization and induction of defects resembling those caused by retinoic acid toxicity. Conversely, antisense morpholino-mediated knockdown of endogenous rdhe2 results in phenotypes consistent with retinoic acid deficiency, such as defects in anterior neural tube closure, microcephaly with small eye formation, disruption of somitogenesis, and curved body axis with bent tail. Higher doses of morpholino induce embryonic lethality. Analyses of retinoic acid levels using either endogenous retinoic acid-sensitive gene hoxd4 or retinoic acid reporter cell line both show that the levels of retinoic acid are significantly decreased in rdhe2 morphants. Taken together, these results provide strong evidence that Xenopus rdhe2 functions as a retinol dehydrogenase essential for frog embryonic development in vivo. Importantly, the retinol oxidizing activity of frog rdhe2 is conserved in its mouse homologs, suggesting that rdhe2-related enzymes may represent the previously unrecognized physiologically relevant retinol dehydrogenases that contribute to retinoic acid biosynthesis in higher vertebrates.
    Journal of Biological Chemistry 01/2012; 287(12):9061-71. DOI:10.1074/jbc.M111.336727 · 4.57 Impact Factor
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    Seung-Ah Lee · Olga V Belyaeva · Natalia Y Kedishvili
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    ABSTRACT: Retinol dehydrogenase 12 (RDH12) is a microsomal enzyme that catalyzes the reduction of all-trans-retinaldehyde to all-trans-retinol when expressed in cells. Mutations in RDH12 cause severe retinal degeneration; however, some of the disease-associated RDH12 mutants retain significant catalytic activity. Our previous study (Lee et al., 2010 [9]) demonstrated that the catalytically active T49M and I51N variants of RDH12 undergo accelerated degradation through the ubiquitin-proteosome system, which results in reduced levels of these proteins in the cells. Here, we investigated whether the stabilization of T49M or I51N RDH12 protein levels through the inhibition of proteosome activity or improved folding could rescue their retinaldehyde reductase activity. For the T49M variant, the inhibition of proteosome activity resulted in an increased level of T49M protein in the microsomal fraction. The higher level of the T49M variant in microsomes correlated with the higher microsomal retinaldehyde reductase activity. T49M-expressing living cells treated with the inhibitors of proteosome activity or with dimethyl sulfoxide exhibited an increase in the conversion of retinaldehyde to retinol, consistent with the recovery of functional RDH12 protein. On the other hand, accumulation of the I51N variant in the microsomes did not result in higher retinaldehyde reductase activity of the microsomes or cells. These results provide a proof of concept that, at least in the case of the T49M variant, the prevention of accelerated degradation could lead to restoration of its function in the cells. This finding justifies further search for more efficient and clinically relevant compounds for stabilizing the T49M variant activity.
    Chemico-biological interactions 05/2011; 191(1-3):55-9. DOI:10.1016/j.cbi.2011.01.001 · 2.58 Impact Factor
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    ABSTRACT: Introduction.
    Chemico-biological interactions 03/2011; 191(1-3):1. DOI:10.1016/j.cbi.2011.03.002 · 2.58 Impact Factor
  • Seung-Ah Lee · Olga V Belyaeva · Lizhi Wu · Natalia Y Kedishvili
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    ABSTRACT: Retinoic acid is essential for skin growth and differentiation, and its concentration in skin is controlled tightly. In humans, four different members of the short-chain dehydrogenase/reductase (SDR) superfamily of proteins were proposed to catalyze the rate-limiting step in the biosynthesis of retinoic acid (the oxidation of retinol to retinaldehyde). Epidermis contains at least three of these enzymes, but their relative importance for retinoic acid biosynthesis and regulation of gene expression during growth and differentiation of epidermis is not known. Here, we investigated the effect of the four human SDRs on retinoic acid biosynthesis, and their impact on growth and differentiation of keratinocytes using organotypic skin raft culture model of human epidermis. The results of this study demonstrate that ectopic expression of retinol dehydrogenase 10 (RDH10, SDR16C4) in skin rafts dramatically increases proliferation and inhibits differentiation of keratinocytes, consistent with the increased steady-state levels of retinoic acid and activation of retinoic acid-inducible genes in RDH10 rafts. In contrast, SDRs with dual retinol/sterol substrate specificity, namely retinol dehydrogenase 4 (RoDH4, SDR9C8), RoDH-like 3α-hydroxysteroid dehydrogenase (RL-HSD, SDR9C6), and RDH-like SDR (RDHL, SDR9C4) do not affect the expression of retinoic acid-inducible genes but alter the expression levels of several components of extracellular matrix. These results reveal essential differences in the metabolic contribution of RDH10 versus retinol/sterol dehydrogenases to retinoic acid biosynthesis and provide the first evidence that non-retinoid metabolic products of retinol/sterol dehydrogenases affect gene expression in human epidermis.
    Journal of Biological Chemistry 02/2011; 286(15):13550-60. DOI:10.1074/jbc.M110.181065 · 4.57 Impact Factor
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    Seung-Ah Lee · Olga V Belyaeva · Natalia Y Kedishvili
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    ABSTRACT: Mutations in retinol dehydrogenase 12 (RDH12) cause severe retinal degeneration. However, some of the disease-associated RDH12 mutants retain significant catalytic activity, indicating the existence of additional pathophysiological mechanisms. This study demonstrates that the catalytically active T49M and I51N mutants undergo accelerated degradation, which results in their reduced cellular levels. Inhibition of proteasome leads to significant accumulation of ubiquitylated T49M and I51N. Furthermore, the degree of ubiquitylation strongly correlates with the half-lives of the proteins. These results suggest that the accelerated degradation of RDH12 mutants by the ubiquitin-proteasome system contributes to the pathophysiology and phenotypic variability associated with mutations in the RDH12 gene.
    FEBS letters 12/2009; 584(3):507-10. DOI:10.1016/j.febslet.2009.12.009 · 3.17 Impact Factor
  • Olga V. Belyaeva · Seung-Ah Lee · Oleg V. Kolupaev · Natalia Y. Kedishvili
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    ABSTRACT: BackgroundIn chordates, retinoid metabolism is an important target of short-chain dehydrogenases/reductases (SDRs). It is not known whether SDRs play a role in retinoid metabolism of protostomes, such as Drosophila melanogaster.MethodsDrosophila genome was searched for genes encoding proteins with ∼ 50% identity to human retinol dehydrogenase 12 (RDH12). The corresponding proteins were expressed in Sf9 cells and biochemically characterized. Their phylogenetic relationships were analyzed using PHYLIP software.ResultsA total of six Drosophila SDR genes were identified. Five of these genes are clustered on chromosome 2 and one is located on chromosome X. The deduced proteins are 300 to 406 amino acids long and are associated with microsomal membranes. They recognize all-trans-retinaldehyde and all-trans-3-hydroxyretinaldehyde as substrates and prefer NADPH as a cofactor. Phylogenetically, Drosophila SDRs belong to the same branch of the SDR superfamily as human RDH12, indicating a common ancestry early in bilaterian evolution, before a protostome–deuterostome split.ConclusionsSimilarities in the substrate and cofactor specificities of Drosophila versus human SDRs suggest conservation of their function in retinoid metabolism throughout protostome and deuterostome phyla.General significanceThe discovery of Drosophila retinaldehyde reductases sheds new light on the conversion of β-carotene and zeaxantine to visual pigment and provides a better understanding of the evolutionary roots of retinoid-active SDRs.
    Biochimica et Biophysica Acta 10/2009; 1790(10-1790):1266-1273. DOI:10.1016/j.bbagen.2009.06.002 · 4.66 Impact Factor
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    Biophysical Journal 02/2009; 96(3):613-. DOI:10.1016/j.bpj.2008.12.3244 · 3.97 Impact Factor
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    X Parés · J Farrés · N Kedishvili · G Duester
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    ABSTRACT: Retinoic acid (RA), the most active retinoid, is synthesized in two steps from retinol. The first step, oxidation of retinol to retinaldehyde, is catalyzed by cytosolic alcohol dehydrogenases (ADHs) of the medium-chain dehydrogenase/reductase (MDR) superfamily and microsomal retinol dehydrogenases (RDHs) of the short-chain dehydrogenase/reductase (SDR) superfamily. The second step, oxidation of retinaldehyde to RA, is catalyzed by several aldehyde dehydrogenases. ADH1 and ADH2 are the major MDR enzymes in liver retinol detoxification, while ADH3 (less active) and ADH4 (most active) participate in RA generation in tissues. Several NAD(+)- and NADP(+)-dependent SDRs are retinoid active. Their in vivo contribution has been demonstrated in the visual cycle (RDH5, RDH12), adult retinoid homeostasis (RDH1) and embryogenesis (RDH10). K(m) values for most retinoid-active ADHs and RDHs are close to 1 microM or lower, suggesting that they participate physiologically in retinol/retinaldehyde interconversion. Probably none of these enzymes uses retinoids bound to cellular retinol-binding protein, but only free retinoids. The large number of enzymes involved in the two directions of this step, also including aldo-keto reductases, suggests that retinaldehyde levels are strictly regulated.
    Cellular and Molecular Life Sciences CMLS 12/2008; 65(24):3936-49. DOI:10.1007/s00018-008-8591-3 · 5.81 Impact Factor
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    ABSTRACT: Short-chain dehydrogenases/reductases (SDR) constitute one of the largest enzyme superfamilies with presently over 46,000 members. In phylogenetic comparisons, members of this superfamily show early divergence where the majority have only low pairwise sequence identity, although sharing common structural properties. The SDR enzymes are present in virtually all genomes investigated, and in humans over 70 SDR genes have been identified. In humans, these enzymes are involved in the metabolism of a large variety of compounds, including steroid hormones, prostaglandins, retinoids, lipids and xenobiotics. It is now clear that SDRs represent one of the oldest protein families and contribute to essential functions and interactions of all forms of life. As this field continues to grow rapidly, a systematic nomenclature is essential for future annotation and reference purposes. A functional subdivision of the SDR superfamily into at least 200 SDR families based upon hidden Markov models forms a suitable foundation for such a nomenclature system, which we present in this paper using human SDRs as examples.
    Chemico-biological interactions 12/2008; 178(1-3):94-8. DOI:10.1016/j.cbi.2008.10.040 · 2.58 Impact Factor
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    ABSTRACT: Throughout adulthood, Bruch membrane (BrM) accumulates esterified cholesterol (EC) associated with abundant 60- to 80-nm-diameter lipoprotein-like particles (LLP), putative apolipoprotein B (apoB) lipoproteins secreted by the retinal pigment epithelium (RPE). In the present study, neutral lipid, phospholipids, and retinoid components of human BrM-LLP were assayed. Particles isolated from paired choroids of human donors were subjected to comprehensive lipid profiling (preparative liquid chromatography [LC] gas chromatography [GC]), thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), Western blot analysis, and negative stain electron microscopy. Results were compared to plasma lipoproteins isolated from normolipemic volunteers and to conditioned medium from RPE-J cells supplemented with palmitate to induce particle synthesis and secretion. EC was the largest component (32.4+/-7.9 mol%) of BrM-LLP lipids. EC was 11.3-fold more abundant than triglyceride (TG), unlike large apoB lipoproteins in plasma. Of the fatty acids (FA) esterified to cholesterol, linoleate (18:2n6) was the most abundant (41.7+/-4.7 mol%). Retinyl ester (RE) was detectable at picomolar levels in BrM-LLP. Notably scarce in any BrM-LLP lipid class was the photoreceptor-abundant FA docosahexaenoate (DHA, 22:6n3). RPE-J cells synthesized apoB and numerous EC-rich spherical particles. BrM-LLP composition resembles plasma LDL more than it does photoreceptors. An EC-rich core is possible for newly synthesized lipoproteins as well as those processed in plasma. Abundant EC could contribute to a transport barrier in aging and lesion formation in age-related maculopathy (ARM). Analysis of BrM-LLP composition has revealed new aspects of retinal cholesterol and retinoid homeostasis.
    Investigative ophthalmology & visual science 10/2008; 50(2):870-7. DOI:10.1167/iovs.08-2376 · 3.40 Impact Factor
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    Seung-Ah Lee · Olga V Belyaeva · Natalia Y Kedishvili
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    ABSTRACT: The mRNA encoding a putative human enzyme named Epidermal Retinol Dehydrogenase 2 (RDH-E2) was found to be significantly elevated in psoriatic skin [Y. Matsuzaka, K. Okamoto, H. Tsuji, T. Mabuchi, A. Ozawa, G. Tamiya, H. Inoko, Identification of the hRDH-E2 gene, a novel member of the SDR family, and its increased expression in psoriatic lesion, Biochem. Biophys. Res. Commun. 297 (2002) 1171-1180]. This finding led the authors to propose that RDH-E2 may be involved in the pathogenesis of psoriasis through its potential role in retinoic acid biosynthesis and stimulation of keratinocyte proliferation. However, enzymatic activity for RDH-E2 has never been demonstrated. RDH-E2 is a member of the short-chain dehydrogenase/reductase (SDR) superfamily of proteins, and is most closely related to the group of SDRs comprised of both NAD(+)- and NADP(+)-dependent enzymes with activities toward retinoid and steroid substrates. In this study, we began the characterization of RDH-E2 protein in order to determine whether it might play a role in retinoic acid biosynthesis. The results of this study show that, similarly to other SDR-type retinol dehydrogenases, RDH-E2 appears to be associated with the membranes of endoplasmic reticulum. Furthermore, RDH-E2 expressed in Sf9 insect cells as a fusion to the C-terminal His(6)-tag and purified using Ni(2+)-affinity chromatography recognizes all-trans-retinol and all-trans-retinaldehyde as substrates and exhibits a strong preference for NAD(+)/NADH as cofactors. Specific activity of RDH-E2 toward all-trans-retinoids is much lower than that of other retinoid-active SDRs, such as human RoDH4 or RDH10. The preference for NAD(+) suggests that RDH-E2 is likely to function in the oxidative direction in vivo, further supporting its potential role in the oxidation of retinol to retinaldehyde for retinoic acid biosynthesis in human keratinocytes.
    Chemico-biological interactions 10/2008; 178(1-3):182-7. DOI:10.1016/j.cbi.2008.09.019 · 2.58 Impact Factor
  • Olga V Belyaeva · Mary P Johnson · Natalia Y Kedishvili
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    ABSTRACT: Human retinol dehydrogenase 10 (RDH10) was implicated in the oxidation of all-trans-retinol for biosynthesis of all-trans-retinoic acid, however, initial assays suggested that RDH10 prefers NADP(+) as a cofactor, undermining its role as an oxidative enzyme. Here, we present evidence that RDH10 is, in fact, a strictly NAD(+)-dependent enzyme with multisubstrate specificity that recognizes cis-retinols as well as all-trans-retinol as substrates. RDH10 has a relatively high apparent K(m) value for NAD(+) (~100 microm) but the lowest apparent K(m) value for all-trans-retinol (~0.035 microm) among all NAD(+)-dependent retinoid oxidoreductases. Due to its high affinity for all-trans-retinol, RDH10 exhibits a greater rate of retinol oxidation in the presence of cellular retinol-binding protein type I (CRBPI) than human microsomal RoDH4, but like RoDH4, RDH10 does not recognize retinol bound to CRBPI as a substrate. Consistent with its preference for NAD(+), RDH10 functions exclusively in the oxidative direction in the cells, increasing the levels of retinaldehyde and retinoic acid. Targeted small interfering RNA-mediated silencing of endogenous RDH10 or RoDH4 expression in human cells results in a significant decrease in retinoic acid production from retinol, identifying both human enzymes as physiologically relevant retinol dehydrogenases. The dual cis/trans substrate specificity suggests a dual physiological role for RDH10: in the biosynthesis of 11-cis-retinaldehyde for vision as well as the biosynthesis of all-trans-retinoic acid for differentiation and development.
    Journal of Biological Chemistry 08/2008; 283(29):20299-308. DOI:10.1074/jbc.M800019200 · 4.57 Impact Factor
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    Seung-Ah Lee · Olga V Belyaeva · Natalia Y Kedishvili
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    ABSTRACT: Mutations in human Retinol Dehydrogenase 12 (RDH12) are known to cause photoreceptor cell death but the physiological function of RDH12 in photoreceptors remains poorly understood. In vitro, RDH12 recognizes both retinoids and medium-chain aldehydes as substrates. Our previous study suggested that RDH12 protects cells against toxic levels of retinaldehyde and retinoic acid [S.A. Lee, O.V. Belyaeva, I.K. Popov, N.Y. Kedishvili, Overproduction of bioactive retinoic acid in cells expressing disease-associated mutants of retinol dehydrogenase 12, J. Biol. Chem. 282 (2007) 35621-35628]. Here, we investigated whether RDH12 can also protect cells against highly reactive medium-chain aldehydes. Analysis of cell survival demonstrated that RDH12 was protective against nonanal but not against 4-hydroxynonenal. At high concentrations, nonanal inhibited the activity of RDH12 towards retinaldehyde, suggesting that nonanal was metabolized by RDH12. 4-Hydroxynonenal did not inhibit the RDH12 retinaldehyde reductase activity, but it strongly inhibited the activities of lecithin:retinol acyl transferase and aldehyde dehydrogenase, resulting in decreased levels of retinyl esters and retinoic acid and accumulation of unesterified retinol. Thus, the results of this study showed that RDH12 is more effective in protection against retinaldehyde than against medium-chain aldehydes, and that medium-chain aldehydes, especially 4-hydroxynonenal, severely disrupt cellular retinoid homeostasis. Together, these findings provide a new insight into the effects of lipid peroxidation products and the impact of oxidative stress on retinoid metabolism.
    Biochimica et Biophysica Acta 07/2008; 1782(6):421-5. DOI:10.1016/j.bbadis.2008.03.004 · 4.66 Impact Factor
  • Seung-Ah Lee · Olga V. Belyaeva · Natalia Y. Kedishvili
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    Olga V Belyaeva · Olga V Korkina · Anton V Stetsenko · Natalia Y Kedishvili
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    ABSTRACT: Retinol dehydrogenase 13 (RDH13) is a recently identified short-chain dehydrogenase/reductase related to microsomal retinoid oxidoreductase RDH11. In this study, we examined the distribution of RDH13 in human tissues, determined its subcellular localization and characterized the substrate and cofactor specificity of purified RDH13 in order to better understand its properties. The results of this study demonstrate that RDH13 exhibits a wide tissue distribution and, by contrast with other members of the RDH11-like group of short-chain dehydrogenases/reductases, is a mitochondrial rather than a microsomal protein. Protease protection assays suggest that RDH13 is localized on the outer side of the inner mitochondrial membrane. Kinetic analysis of the purified protein shows that RDH13 is catalytically active and recognizes retinoids as substrates. Similar to the microsomal RDHs, RDH11, RDH12 and RDH14, RDH13 exhibits a much lower Km value for NADPH than for NADH and has a greater catalytic efficiency in the reductive than in the oxidative direction. The localization of RDH13 at the entrance to the mitochondrial matrix suggests that it may function to protect mitochondria against oxidative stress associated with the highly reactive retinaldehyde produced from dietary beta-carotene.
    FEBS Journal 02/2008; 275(1):138-47. DOI:10.1111/j.1742-4658.2007.06184.x · 4.00 Impact Factor
  • Seung-Ah Lee · Olga V Belyaeva · Ivan K Popov · Natalia Y Kedishvili
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    ABSTRACT: Retinol dehydrogenase 12 (RDH12) is an NADP(+)-dependent oxidoreductase that in vitro catalyzes the reduction of all-trans-retinaldehyde to all-trans-retinol or the oxidation of retinol to retinaldehyde depending on substrate and cofactor availability. Recent studies have linked the mutations in RDH12 to severe early-onset autosomal recessive retinal dystrophy. The biochemical basis of photoreceptor cell death caused by mutations in RDH12 is not clear because the physiological role of RDH12 is not yet fully understood. Here we demonstrate that, although bi-directional in vitro, in living cells, RDH12 acts exclusively as a retinaldehyde reductase, shifting the retinoid homeostasis toward the increased levels of retinol and decreased levels of bioactive retinoic acid. The retinaldehyde reductase activity of RDH12 protects the cells from retinaldehyde-induced cell death, especially at high retinaldehyde concentrations, and this protective effect correlates with the lower levels of retinoic acid in RDH12-expressing cells. Disease-associated mutants of RDH12, T49M and I51N, exhibit significant residual activity in vitro, but are unable to control retinoic acid levels in the cells because of their dramatically reduced affinity for NADPH and much lower protein expression levels. These results suggest that RDH12 acts as a regulator of retinoic acid biosynthesis and protects photoreceptors against overproduction of retinoic acid from all-trans-retinaldehyde, which diffuses into the inner segments of photoreceptors from illuminated rhodopsin. These results provide a novel insight into the mechanism of retinal degeneration associated with mutations in RDH12 and are consistent with the observation that RDH12-null mice are highly susceptible to light-induced retinal apoptosis in cone and rod photoreceptors.
    Journal of Biological Chemistry 01/2008; 282(49):35621-8. DOI:10.1074/jbc.M706372200 · 4.57 Impact Factor

Publication Stats

2k Citations
209.60 Total Impact Points


  • 2005–2014
    • University of Alabama at Birmingham
      • Department of Biochemistry and Molecular Genetics
      Birmingham, Alabama, United States
  • 2006
    • Autonomous University of Barcelona
      • Department of Biochemistry and Molecular Biology
      Cerdanyola del Vallès, Catalonia, Spain
  • 2002–2004
    • University of Washington Seattle
      Seattle, Washington, United States
  • 1991–2004
    • Indiana University-Purdue University Indianapolis
      • • Department of Biochemistry and Molecular Biology
      • • Department of Medicine
      Indianapolis, Indiana, United States
  • 2000–2003
    • University of Missouri - Kansas City
      • Division of Molecular Biology and Biochemistry
      Kansas City, Missouri, United States
  • 1997
    • Purdue University
      ウェストラファイエット, Indiana, United States
  • 1995
    • The American Society for Biochemistry and Molecular Biology
      Indianapolis, Indiana, United States