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Robert A Harris - One of the best experts on this subject based on the ideXlab platform.
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Pyruvate Dehydrogenase Kinase 4 deficiency attenuates cisplatin induced acute kidney injury
Kidney International, 2017Co-Authors: Chang Joo Oh, Robert A Harris, Nam Ho Jeoung, Jae-han Jeon, Sungmi Park, Youngkeun Choi, Chaemyeong Ha, Mi Sun Choe, Hee Seok Kweon, Keungyu ParkAbstract:Clinical prescription of cisplatin, one of the most widely used chemotherapeutic agents, is limited by its side effects, particularly tubular injury–associated nephrotoxicity. Since details of the underlying mechanisms are not fully understood, we investigated the role of Pyruvate Dehydrogenase Kinase (PDK) in cisplatin-induced acute kidney injury. Among the PDK isoforms, PDK4 mRNA and protein levels were markedly increased in the kidneys of mice treated with cisplatin, and c-Jun N-terminal Kinase activation was involved in cisplatin-induced renal PDK4 expression. Treatment with the PDK inhibitor sodium dichloroacetate (DCA) or genetic knockout of PDK4 attenuated the signs of cisplatin-induced acute kidney injury, including apoptotic morphology of the kidney tubules along with numbers of TUNEL-positive cells, cleaved caspase-3, and renal tubular injury markers. Cisplatin-induced suppression of the mitochondrial membrane potential, oxygen consumption rate, expression of electron transport chain components, cytochrome c oxidase activity, and disruption of mitochondrial morphology were noticeably improved in the kidneys of DCA-treated or PDK4 knockout mice. Additionally, levels of the oxidative stress marker 4-hydroxynonenal and mitochondrial reactive oxygen species were attenuated, whereas superoxide dismutase 2 and catalase expression and glutathione synthetase and glutathione levels were recovered in DCA-treated or PDK4 knockout mice. Interestingly, lipid accumulation was considerably attenuated in DCA-treated or PDK4 knockout mice via recovered expression of peroxisome proliferator-activated receptor-α and coactivator PGC-1α, which was accompanied by recovery of mitochondrial biogenesis. Thus, PDK4 mediates cisplatin-induced acute kidney injury, suggesting that PDK4 might be a therapeutic target for attenuating cisplatin-induced acute kidney injury.
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overexpression of Pyruvate Dehydrogenase Kinase 4 in heart perturbs metabolism and exacerbates calcineurin induced cardiomyopathy
American Journal of Physiology-heart and Circulatory Physiology, 2008Co-Authors: Guixiang Zhao, Nam Ho Jeoung, Shawn C Burgess, Kimberly A Rosaaenstowe, Takeshi Inagaki, Shuaib Latif, John M Shelton, John Mcanally, Rhonda Basselduby, Robert A HarrisAbstract:The heart adapts to changes in nutritional status and energy demands by adjusting its relative metabolism of carbohydrates and fatty acids. Loss of this metabolic flexibility such as occurs in diabetes mellitus is associated with cardiovascular disease and heart failure. To study the long-term consequences of impaired metabolic flexibility, we have generated mice that overexpress Pyruvate Dehydrogenase Kinase (PDK)4 selectively in the heart. Hearts from PDK4 transgenic mice have a marked decrease in glucose oxidation and a corresponding increase in fatty acid catabolism. Although no overt cardiomyopathy was observed in the PDK4 transgenic mice, introduction of the PDK4 transgene into mice expressing a constitutively active form of the phosphatase calcineurin, which causes cardiac hypertrophy, caused cardiomyocyte fibrosis and a striking increase in mortality. These results demonstrate that cardiac-specific overexpression of PDK4 is sufficient to cause a loss of metabolic flexibility that exacerbates cardiomyopathy caused by the calcineurin stress-activated pathway.
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role of Pyruvate Dehydrogenase Kinase isoenzyme 4 pdhk4 in glucose homoeostasis during starvation
Biochemical Journal, 2006Co-Authors: Nam Ho Jeoung, Pengfei Wu, Jerzy Jaskiewicz, Mandar Joshi, Cheryl B Bock, Anna A Depaoliroach, Robert A HarrisAbstract:The PDC (Pyruvate Dehydrogenase complex) is strongly inhibited by phosphorylation during starvation to conserve substrates for gluconeogenesis. The role of PDHK4 (Pyruvate Dehydrogenase Kinase isoenzyme 4) in regulation of PDC by this mechanism was investigated with PDHK4−/− mice (homozygous PDHK4 knockout mice). Starvation lowers blood glucose more in mice lacking PDHK4 than in wild-type mice. The activity state of PDC (percentage dephosphorylated and active) is greater in kidney, gastrocnemius muscle, diaphragm and heart but not in the liver of starved PDHK4−/− mice. Intermediates of the gluconeogenic pathway are lower in concentration in the liver of starved PDHK4−/− mice, consistent with a lower rate of gluconeogenesis due to a substrate supply limitation. The concentration of gluconeogenic substrates is lower in the blood of starved PDHK4−/− mice, consistent with reduced formation in peripheral tissues. Isolated diaphragms from starved PDHK4−/− mice accumulate less lactate and Pyruvate because of a faster rate of Pyruvate oxidation and a reduced rate of glycolysis. BCAAs (branched chain amino acids) are higher in the blood in starved PDHK4−/− mice, consistent with lower blood alanine levels and the importance of BCAAs as a source of amino groups for alanine formation. Non-esterified fatty acids are also elevated more in the blood of starved PDHK4−/− mice, consistent with lower rates of fatty acid oxidation due to increased rates of glucose and Pyruvate oxidation due to greater PDC activity. Up-regulation of PDHK4 in tissues other than the liver is clearly important during starvation for regulation of PDC activity and glucose homoeostasis.
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regulation of Pyruvate Dehydrogenase Kinase expression by peroxisome proliferator activated receptor α ligands glucocorticoids and insulin
Diabetes, 2002Co-Authors: Boli Huang, Pengfei Wu, Melissa M Bowkerkinley, Robert A HarrisAbstract:Pyruvate Dehydrogenase Kinase (PDK) catalyzes phosphorylation and inactivation of the Pyruvate Dehydrogenase complex (PDC). Two isoforms of this mitochondrial Kinase (PDK2 and PDK4) are induced in a tissue-specific manner in response to starvation and diabetes. Inactivation of PDC by increased PDK activity promotes gluconeogenesis by conserving three-carbon substrates. This helps maintain glucose levels during starvation, but is detrimental in diabetes. Factors that regulate PDK2 and PDK4 expression were examined in Morris hepatoma 7800 C1 cells. The peroxisome proliferator−activated receptor-α (PPAR-α) agonist WY-14,643 and the glucocorticoid dexamethasone increased PDK4 mRNA levels. Neither compound affected the half-life of the PDK4 message, suggesting that both increase gene transcription. Fatty acids caused an increase in the PDK4 message comparable to that induced by WY-14,643. Insulin prevented and reversed the stimulatory effects of dexamethasone on PDK4 gene expression, but was less effective against the stimulatory effects of WY-14,643 and fatty acids. Insulin also decreased the abundance of the PDK2 message. The findings suggest that decreased levels of insulin and increased levels of fatty acids and glucocorticoids promote PDK4 gene expression in starvation and diabetes. The decreased level of insulin is likely responsible for the increase in PDK2 mRNA level in starvation and diabetes.
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structure of Pyruvate Dehydrogenase Kinase novel folding pattern for a serine protein Kinase
Journal of Biological Chemistry, 2001Co-Authors: Nicklaus C Steussy, Kirill M. Popov, Robert A Harris, Melissa M Bowkerkinley, Robert B Sloan, Jean A HamiltonAbstract:Abstract The structure of mitochondrial Pyruvate Dehydrogenase Kinase isozyme 2 is of interest because it represents a family of serine-specific protein Kinases that lack sequence similarity with all other eukaryotic protein Kinases. Similarity exists instead with key motifs of prokaryotic histidine protein Kinases and a family of eukaryotic ATPases. The 2.5-A crystal structure reported here reveals that Pyruvate Dehydrogenase Kinase isozyme 2 has two domains of about the same size. The N-terminal half is dominated by a bundle of four amphipathic α-helices, whereas the C-terminal half is folded into an α/β sandwich that contains the nucleotide-binding site. Analysis of the structure reveals this C-terminal domain to be very similar to the nucleotide-binding domain of bacterial histidine Kinases, but the catalytic mechanism appears similar to that of the eukaryotic serine Kinases and ATPases.
Nam Ho Jeoung - One of the best experts on this subject based on the ideXlab platform.
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Pyruvate Dehydrogenase Kinase 4 deficiency attenuates cisplatin induced acute kidney injury
Kidney International, 2017Co-Authors: Chang Joo Oh, Robert A Harris, Nam Ho Jeoung, Jae-han Jeon, Sungmi Park, Youngkeun Choi, Chaemyeong Ha, Mi Sun Choe, Hee Seok Kweon, Keungyu ParkAbstract:Clinical prescription of cisplatin, one of the most widely used chemotherapeutic agents, is limited by its side effects, particularly tubular injury–associated nephrotoxicity. Since details of the underlying mechanisms are not fully understood, we investigated the role of Pyruvate Dehydrogenase Kinase (PDK) in cisplatin-induced acute kidney injury. Among the PDK isoforms, PDK4 mRNA and protein levels were markedly increased in the kidneys of mice treated with cisplatin, and c-Jun N-terminal Kinase activation was involved in cisplatin-induced renal PDK4 expression. Treatment with the PDK inhibitor sodium dichloroacetate (DCA) or genetic knockout of PDK4 attenuated the signs of cisplatin-induced acute kidney injury, including apoptotic morphology of the kidney tubules along with numbers of TUNEL-positive cells, cleaved caspase-3, and renal tubular injury markers. Cisplatin-induced suppression of the mitochondrial membrane potential, oxygen consumption rate, expression of electron transport chain components, cytochrome c oxidase activity, and disruption of mitochondrial morphology were noticeably improved in the kidneys of DCA-treated or PDK4 knockout mice. Additionally, levels of the oxidative stress marker 4-hydroxynonenal and mitochondrial reactive oxygen species were attenuated, whereas superoxide dismutase 2 and catalase expression and glutathione synthetase and glutathione levels were recovered in DCA-treated or PDK4 knockout mice. Interestingly, lipid accumulation was considerably attenuated in DCA-treated or PDK4 knockout mice via recovered expression of peroxisome proliferator-activated receptor-α and coactivator PGC-1α, which was accompanied by recovery of mitochondrial biogenesis. Thus, PDK4 mediates cisplatin-induced acute kidney injury, suggesting that PDK4 might be a therapeutic target for attenuating cisplatin-induced acute kidney injury.
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inhibition of Pyruvate Dehydrogenase Kinase 2 protects against hepatic steatosis through modulation of tricarboxylic acid cycle anaplerosis and ketogenesis
Diabetes, 2016Co-Authors: Younghoon Go, Ji Yun Jeong, Nam Ho Jeoung, Keungyu Park, Jae-han Jeon, Youngkeun Choi, Chaemyeong Ha, Hyeonji Kang, Bo Yoon Park, So Young ParkAbstract:Hepatic steatosis is associated with increased insulin resistance and tricarboxylic acid (TCA) cycle flux, but decreased ketogenesis and Pyruvate Dehydrogenase complex (PDC) flux. This study examined whether hepatic PDC activation by inhibition of Pyruvate Dehydrogenase Kinase 2 (PDK2) ameliorates these metabolic abnormalities. Wild-type mice fed a high-fat diet exhibited hepatic steatosis, insulin resistance, and increased levels of Pyruvate, TCA cycle intermediates, and malonyl-CoA but reduced ketogenesis and PDC activity due to PDK2 induction. Hepatic PDC activation by PDK2 inhibition attenuated hepatic steatosis, improved hepatic insulin sensitivity, reduced hepatic glucose production, increased capacity for β-oxidation and ketogenesis, and decreased the capacity for lipogenesis. These results were attributed to altered enzymatic capacities and a reduction in TCA anaplerosis that limited the availability of oxaloacetate for the TCA cycle, which promoted ketogenesis. The current study reports that increasing hepatic PDC activity by inhibition of PDK2 ameliorates hepatic steatosis and insulin sensitivity by regulating TCA cycle anaplerosis and ketogenesis. The findings suggest PDK2 is a potential therapeutic target for nonalcoholic fatty liver disease.
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correction corrigendum Pyruvate Dehydrogenase Kinase 4 promotes vascular calcification via smad1 5 8 phosphorylation
Scientific Reports, 2016Co-Authors: Ji Yun Jeong, Nam Ho Jeoung, Chang Joo Oh, Sungmi Park, Youngkeun Choi, Ji Yeon Do, Younghoon Go, Je Yong Choi, Chaemyeong Ha, Huengsik ChoiAbstract:Vascular calcification, a pathologic response to defective calcium and phosphate homeostasis, is strongly associated with cardiovascular mortality and morbidity. In this study, we have observed that Pyruvate Dehydrogenase Kinase 4 (PDK4) is upregulated and Pyruvate Dehydrogenase complex phosphorylation is increased in calcifying vascular smooth muscle cells (VSMCs) and in calcified vessels of patients with atherosclerosis, suggesting that PDK4 plays an important role in vascular calcification. Both genetic and pharmacological inhibition of PDK4 ameliorated the calcification in phosphate-treated VSMCs and aortic rings and in vitamin D3-treated mice. PDK4 augmented the osteogenic differentiation of VSMCs by phosphorylating SMAD1/5/8 via direct interaction, which enhances BMP2 signaling. Furthermore, increased expression of PDK4 in phosphate-treated VSMCs induced mitochondrial dysfunction followed by apoptosis. Taken together, our results show that upregulation of PDK4 promotes vascular calcification by increasing osteogenic markers with no adverse effect on bone formation, demonstrating that PDK4 is a therapeutic target for vascular calcification.
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Pyruvate Dehydrogenase Kinase 4 promotes vascular calcification via smad1 5 8 phosphorylation
Scientific Reports, 2015Co-Authors: Ji Yun Jeong, Chang Joo Oh, Sungmi Park, Youngkeun Choi, Ji Yeon Do, Younghoon Go, Chaemyung Ha, Je Yong Choi, Nam Ho JeoungAbstract:Vascular calcification, a pathologic response to defective calcium and phosphate homeostasis, is strongly associated with cardiovascular mortality and morbidity. In this study, we have observed that Pyruvate Dehydrogenase Kinase 4 (PDK4) is upregulated and Pyruvate Dehydrogenase complex phosphorylation is increased in calcifying vascular smooth muscle cells (VSMCs) and in calcified vessels of patients with atherosclerosis, suggesting that PDK4 plays an important role in vascular calcification. Both genetic and pharmacological inhibition of PDK4 ameliorated the calcification in phosphate-treated VSMCs and aortic rings and in vitamin D3-treated mice. PDK4 augmented the osteogenic differentiation of VSMCs by phosphorylating SMAD1/5/8 via direct interaction, which enhances BMP2 signaling. Furthermore, increased expression of PDK4 in phosphate-treated VSMCs induced mitochondrial dysfunction followed by apoptosis. Taken together, our results show that upregulation of PDK4 promotes vascular calcification by increasing osteogenic markers with no adverse effect on bone formation, demonstrating that PDK4 is a therapeutic target for vascular calcification.
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transcriptional regulation of Pyruvate Dehydrogenase Kinase
Diabetes & Metabolism Journal, 2012Co-Authors: Ji Yun Jeong, Nam Ho Jeoung, Keungyu ParkAbstract:The Pyruvate Dehydrogenase complex (PDC) activity is crucial to maintains blood glucose and ATP levels, which largely depends on the phosphorylation status by Pyruvate Dehydrogenase Kinase (PDK) isoenzymes. Although it has been reported that PDC is phosphorylated and inactivated by PDK2 and PDK4 in metabolically active tissues including liver, skeletal muscle, heart, and kidney during starvation and diabetes, the precise mechanisms by which expression of PDK2 and PDK4 are transcriptionally regulated still remains unclear. Insulin represses the expression of PDK2 and PDK4 via phosphorylation of FOXO through PI3K/Akt signaling pathway. Several nuclear hormone receptors activated due to fasting or increased fat supply, including peroxisome proliferator-activated receptors, glucocorticoid receptors, estrogen-related receptors, and thyroid hormone receptors, also participate in the up-regulation of PDK2 and PDK4; however, the endogenous ligands that bind those nuclear receptors have not been identified. It has been recently suggested that growth hormone, adiponectin, epinephrine, and rosiglitazone also control the expression of PDK4 in tissue-specific manners. In this review, we discuss several factors involved in the expressional regulation of PDK2 and PDK4, and introduce current studies aimed at providing a better understanding of the molecular mechanisms that underlie the development of metabolic diseases such as diabetes.
Ji Yun Jeong - One of the best experts on this subject based on the ideXlab platform.
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inhibition of Pyruvate Dehydrogenase Kinase 2 protects against hepatic steatosis through modulation of tricarboxylic acid cycle anaplerosis and ketogenesis
Diabetes, 2016Co-Authors: Younghoon Go, Ji Yun Jeong, Nam Ho Jeoung, Keungyu Park, Jae-han Jeon, Youngkeun Choi, Chaemyeong Ha, Hyeonji Kang, Bo Yoon Park, So Young ParkAbstract:Hepatic steatosis is associated with increased insulin resistance and tricarboxylic acid (TCA) cycle flux, but decreased ketogenesis and Pyruvate Dehydrogenase complex (PDC) flux. This study examined whether hepatic PDC activation by inhibition of Pyruvate Dehydrogenase Kinase 2 (PDK2) ameliorates these metabolic abnormalities. Wild-type mice fed a high-fat diet exhibited hepatic steatosis, insulin resistance, and increased levels of Pyruvate, TCA cycle intermediates, and malonyl-CoA but reduced ketogenesis and PDC activity due to PDK2 induction. Hepatic PDC activation by PDK2 inhibition attenuated hepatic steatosis, improved hepatic insulin sensitivity, reduced hepatic glucose production, increased capacity for β-oxidation and ketogenesis, and decreased the capacity for lipogenesis. These results were attributed to altered enzymatic capacities and a reduction in TCA anaplerosis that limited the availability of oxaloacetate for the TCA cycle, which promoted ketogenesis. The current study reports that increasing hepatic PDC activity by inhibition of PDK2 ameliorates hepatic steatosis and insulin sensitivity by regulating TCA cycle anaplerosis and ketogenesis. The findings suggest PDK2 is a potential therapeutic target for nonalcoholic fatty liver disease.
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correction corrigendum Pyruvate Dehydrogenase Kinase 4 promotes vascular calcification via smad1 5 8 phosphorylation
Scientific Reports, 2016Co-Authors: Ji Yun Jeong, Nam Ho Jeoung, Chang Joo Oh, Sungmi Park, Youngkeun Choi, Ji Yeon Do, Younghoon Go, Je Yong Choi, Chaemyeong Ha, Huengsik ChoiAbstract:Vascular calcification, a pathologic response to defective calcium and phosphate homeostasis, is strongly associated with cardiovascular mortality and morbidity. In this study, we have observed that Pyruvate Dehydrogenase Kinase 4 (PDK4) is upregulated and Pyruvate Dehydrogenase complex phosphorylation is increased in calcifying vascular smooth muscle cells (VSMCs) and in calcified vessels of patients with atherosclerosis, suggesting that PDK4 plays an important role in vascular calcification. Both genetic and pharmacological inhibition of PDK4 ameliorated the calcification in phosphate-treated VSMCs and aortic rings and in vitamin D3-treated mice. PDK4 augmented the osteogenic differentiation of VSMCs by phosphorylating SMAD1/5/8 via direct interaction, which enhances BMP2 signaling. Furthermore, increased expression of PDK4 in phosphate-treated VSMCs induced mitochondrial dysfunction followed by apoptosis. Taken together, our results show that upregulation of PDK4 promotes vascular calcification by increasing osteogenic markers with no adverse effect on bone formation, demonstrating that PDK4 is a therapeutic target for vascular calcification.
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Pyruvate Dehydrogenase Kinase 4 Promotes Vascular Calcification via SMAD1/5/8 Phosphorylation
Scientific Reports, 2015Co-Authors: Ji Yun Jeong, Chang Joo Oh, Sungmi Park, Youngkeun Choi, Ji Yeon, Younghoon GoAbstract:Vascular calcification, a pathologic response to defective calcium and phosphate homeostasis, is strongly associated with cardiovascular mortality and morbidity. In this study, we have observed that Pyruvate Dehydrogenase Kinase 4 (PDK4) is upregulated and Pyruvate Dehydrogenase complex phosphorylation is increased in calcifying vascular smooth muscle cells (VSMCs) and in calcified vessels of patients with atherosclerosis, suggesting that PDK4 plays an important role in vascular calcification. Both genetic and pharmacological inhibition of PDK4 ameliorated the calcification in phosphate-treated VSMCs and aortic rings and in vitamin D3-treated mice. PDK4 augmented the osteogenic differentiation of VSMCs by phosphorylating SMAD1/5/8 via direct interaction, which enhances BMP2 signaling. Furthermore, increased expression of PDK4 in phosphate-treated VSMCs induced mitochondrial dysfunction followed by apoptosis. Taken together, our results show that upregulation of PDK4 promotes vascular calcification by increasing osteogenic markers with no adverse effect on bone formation, demonstrating that PDK4 is a therapeutic target for vascular calcification.
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Pyruvate Dehydrogenase Kinase 4 promotes vascular calcification via smad1 5 8 phosphorylation
Scientific Reports, 2015Co-Authors: Ji Yun Jeong, Chang Joo Oh, Sungmi Park, Youngkeun Choi, Ji Yeon Do, Younghoon Go, Chaemyung Ha, Je Yong Choi, Nam Ho JeoungAbstract:Vascular calcification, a pathologic response to defective calcium and phosphate homeostasis, is strongly associated with cardiovascular mortality and morbidity. In this study, we have observed that Pyruvate Dehydrogenase Kinase 4 (PDK4) is upregulated and Pyruvate Dehydrogenase complex phosphorylation is increased in calcifying vascular smooth muscle cells (VSMCs) and in calcified vessels of patients with atherosclerosis, suggesting that PDK4 plays an important role in vascular calcification. Both genetic and pharmacological inhibition of PDK4 ameliorated the calcification in phosphate-treated VSMCs and aortic rings and in vitamin D3-treated mice. PDK4 augmented the osteogenic differentiation of VSMCs by phosphorylating SMAD1/5/8 via direct interaction, which enhances BMP2 signaling. Furthermore, increased expression of PDK4 in phosphate-treated VSMCs induced mitochondrial dysfunction followed by apoptosis. Taken together, our results show that upregulation of PDK4 promotes vascular calcification by increasing osteogenic markers with no adverse effect on bone formation, demonstrating that PDK4 is a therapeutic target for vascular calcification.
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transcriptional regulation of Pyruvate Dehydrogenase Kinase
Diabetes & Metabolism Journal, 2012Co-Authors: Ji Yun Jeong, Nam Ho Jeoung, Keungyu ParkAbstract:The Pyruvate Dehydrogenase complex (PDC) activity is crucial to maintains blood glucose and ATP levels, which largely depends on the phosphorylation status by Pyruvate Dehydrogenase Kinase (PDK) isoenzymes. Although it has been reported that PDC is phosphorylated and inactivated by PDK2 and PDK4 in metabolically active tissues including liver, skeletal muscle, heart, and kidney during starvation and diabetes, the precise mechanisms by which expression of PDK2 and PDK4 are transcriptionally regulated still remains unclear. Insulin represses the expression of PDK2 and PDK4 via phosphorylation of FOXO through PI3K/Akt signaling pathway. Several nuclear hormone receptors activated due to fasting or increased fat supply, including peroxisome proliferator-activated receptors, glucocorticoid receptors, estrogen-related receptors, and thyroid hormone receptors, also participate in the up-regulation of PDK2 and PDK4; however, the endogenous ligands that bind those nuclear receptors have not been identified. It has been recently suggested that growth hormone, adiponectin, epinephrine, and rosiglitazone also control the expression of PDK4 in tissue-specific manners. In this review, we discuss several factors involved in the expressional regulation of PDK2 and PDK4, and introduce current studies aimed at providing a better understanding of the molecular mechanisms that underlie the development of metabolic diseases such as diabetes.
Emma L Kaplan - One of the best experts on this subject based on the ideXlab platform.
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anilides of r trifluoro 2 hydroxy 2 methylpropionic acid as inhibitors of Pyruvate Dehydrogenase Kinase
Journal of Medicinal Chemistry, 2000Co-Authors: Gregory Raymond Bebernitz, Thomas Daniel Aicher, Christine C Vinluan, Suraj Shivappa Shetty, James L Stanton, Douglas C Knorr, Robert J Strohschein, Leonard Brand, Wei H Wang, Emma L KaplanAbstract:The optimization of a series of anilide derivatives of (R)-3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid as inhibitors of Pyruvate Dehydrogenase Kinase (PDHK) is described that started from N-phenyl-3,3,3-trifluoro-2-hydroxy-2-methylpropanamide 1 (IC50 = 35 ± 1.4 μM). It was found that small electron-withdrawing groups on the ortho position of the anilide, i.e., chloro, acetyl, or bromo, increased potency 20−40-fold. The oral bioavailability of the compounds in this series is optimal (as measured by AUC) when the anilide is substituted at the 4-position with an electron-withdrawing group (i.e., carboxyl, carboxyamide, and sulfoxyamide). N-(2-Chloro-4-isobutylsulfamoylphenyl)-(R)-3,3,3-trifluoro-2-hydroxy-2-methylpropionamide (10a) inhibits PDHK in the primary enzymatic assay with an IC50 of 13 ± 1.5 nM, enhances the oxidation of [14C]lactate into 14CO2 in human fibroblasts, lowers blood lactate levels significantly 2.5 and 5 h after oral doses as low as 30 μmol/kg, and increases the ex vivo activity of...
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secondary amides of r 3 3 3 trifluoro 2 hydroxy 2 methylpropionic acid as inhibitors of Pyruvate Dehydrogenase Kinase
Journal of Medicinal Chemistry, 2000Co-Authors: Thomas Daniel Aicher, Christine C Vinluan, Suraj Shivappa Shetty, James L Stanton, Douglas C Knorr, Leonard Brand, Robert C Anderson, Gary M Coppola, Donald M Sperbeck, Emma L KaplanAbstract:N‘-Methyl-N-(4-tert-butyl-1,2,5,6-tetrahydropyridine)thiourea, SDZ048-619 (1), is a modest inhibitor (IC50 = 180 μM) of Pyruvate Dehydrogenase Kinase (PDHK). In an optimization of the N-methylcarbothioamide moiety of 1, it was discovered that amides with a small acyl group, in particular appropriately substituted amides of (R)-3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid, are inhibitors of PDHK. Utilizing this acyl moiety, herein is reported the rationale leading to the optimization of a series of acylated piperazine derivatives. Methyl substitution of the piperazine at the 2- and 5-positions (with S and R absolute stereochemistry) markedly increased the potency of the lead compound (>1000-fold). Oral bioavailability of the compounds in this series is good and is optimal (as measured by AUC) when the 4-position of the piperazine is substituted with an electron-poor benzoyl moiety. (+)-1-N-[2,5-(S,R)-Dimethyl-4-N-(4-cyanobenzoyl)piperazine]-(R)-3,3,3-trifluoro-2-hydroxy-2-methylpropanamide (14e) inhibi...
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triterpene and diterpene inhibitors of Pyruvate Dehydrogenase Kinase pdk
Bioorganic & Medicinal Chemistry Letters, 1999Co-Authors: Thomas Daniel Aicher, Robert E Damon, Judit Koletar, Christine C Vinluan, Leonard J Brand, Suraj Shivappa Shetty, Emma L Kaplan, William R MannAbstract:Several oximes of triterpenes with a 17-β hydroxyl and abietane derivatives are inhibitors of Pyruvate Dehydrogenase Kinase (PDK) activity. The oxime 12 and dehydroabietyl amine 2 exhibit a blood glucose lowering effect in the diabetic ob/ob mouse after a single oral dose of 100 μmol/kg. However, the mechanism of the blood glucose lowering effect is likely unrelated to PDK inhibition.
Kirill M. Popov - One of the best experts on this subject based on the ideXlab platform.
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Allosteric coupling in Pyruvate Dehydrogenase Kinase 2.
Biochemistry, 2008Co-Authors: Alla Klyuyeva, Alina Tuganova, Kirill M. PopovAbstract:Mitochondrial Pyruvate Dehydrogenase Kinase 2 (PDHK2) phosphorylates the Pyruvate Dehydrogenase multienzyme complex (PDC) and thereby controls the rate of oxidative decarboxylation of Pyruvate. The activity of PDHK2 is regulated by a variety of metabolites such as Pyruvate, NAD + , NADH, CoA, and acetyl-CoA. The inhibitory effect of Pyruvate occurs through the unique binding site, which is specific for Pyruvate and its synthetic analogue dichloroacetate (DCA). The effects of NAD + , NADH, CoA, and acetyl-CoA are mediated by the binding site that recognizes the inner lipoyl-bearing domain (L2) of the dihydrolipoyl transacetylase (E2). Both allosteric sites are separated from the active site of PDHK2 by more than 20 A. Here we show that mutations of three amino acid residues located in the vicinity of the active site of PDHK2 (R250, T302, and Y320) make the Kinase resistant to the inhibitory effect of DCA, thereby uncoupling the active site from the allosteric site. In addition, we provide evidence that substitutions of R250 and T302 can partially or completely uncouple the L2-binding site. Based on the available structural data, R250, T302, and Y320 stabilize the “open” and “closed” conformations of the built-in lid that controls the access of a nucleotide into the nucleotide-binding cavity. This strongly suggests that the mobility of ATP lid is central to the allosteric regulation of PDHK2 activity serving as a conformational switch required for communication between the active site and allosteric sites in the Kinase molecule.
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Amino Acid Residues Responsible for the Recognition of Dichloroacetate by Pyruvate Dehydrogenase Kinase 2
FEBS Letters, 2007Co-Authors: Alla Klyuyeva, Alina Tuganova, Kirill M. PopovAbstract:Dichloroacetate (DCA) is a promising anticancer and antidiabetic compound targeting the mitochondrial Pyruvate Dehydrogenase Kinase (PDHK). This study was undertaken in order to map the DCA-binding site of PDHK2. Here, we present evidence that R114, S83, I157 and, to some extent, H115 are essential for DCA binding. We also show that Y80 and D117 are required for the communication between the DCA-binding site and active site of PDHK2. These observations provide important insights into the mechanism of DCA action that may be useful for the design of new, more potent therapeutic compounds.
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Role of protein-protein interactions in the regulation of Pyruvate Dehydrogenase Kinase activity.
Biochemical Journal, 2005Co-Authors: Alina Tuganova, Kirill M. PopovAbstract:The transacetylase component (E2) of PDC (Pyruvate Dehydrogenase complex) plays a critical role in the regulation of PDHK (Pyruvate Dehydrogenase Kinase) activity. The present study was undertaken to investigate further the molecular mechanism by which E2 modulates the activity of PDHK. In agreement with the earlier results, it was found that the inner L2 (lipoyl-bearing domain 2) of E2 expressed with or without the C-terminal hinge region had little, if any, effect on the Kinase activity, indicating a lack of direct allosteric effect of L2 on PDHK. In marked contrast, significant activation of PDHK was observed with the construct consisting of L2 and the E1BD (E1-binding domain) of E2 (L2-E1BD didomain) suggesting that co-localization and/or mutual orientation of PDHK and E1, facilitated by E2 binding, largely account for the activation of PDHK by the transacetylase component. Isothermal titration calorimetry and glutathione S-transferase pull-down assays established that binding of adenyl nucleotides to the PDHK molecule facilitated the release of L2 domain. In contrast, binding of the L2 domain caused a significant decrease in the affinity of PDHK for ATP. The cross-talk in binding of adenyl nucleotides and the L2 domain to PDHK may indicate the existence of a highly integrated mechanism whereby the exchange of lipoyl-bearing domains presented to PDHK by E2 is coupled with ADP/ATP exchange.
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Formation of functional heterodimers by isozymes 1 and 2 of Pyruvate Dehydrogenase Kinase.
Biochimica et Biophysica Acta, 2003Co-Authors: Igor Boulatnikov, Kirill M. PopovAbstract:Abstract Pyruvate Dehydrogenase Kinase (PDK) is a mitochondrial enzyme responsible for regulation of the Pyruvate Dehydrogenase complex and, consequently, aerobic oxidation of carbohydrate fuels in general. In mammals, there are four genetically and biochemically distinct forms of PDK that are expressed in a tissue-specific manner (PDK1, PDK2, PDK3, and PDK4). These protein Kinases have been shown to function as dimers, but the possibility of heterodimerization between various isozyme subunits has not yet been investigated. Here, we demonstrate that two members of the PDK family, PDK1 and PDK2, form heterodimeric species when coexpressed in the same Escherichia coli cell. The heterodimeric Kinase produced in vivo was purified to near homogeneity by affinity chromatography. The purified Kinase was stable and was not subjected to reassortment of the subunits. The heterodimeric Kinase was catalytically active and was clearly distinct from homodimeric PDK1 or PDK2 with respect to kinetic parameters, site specificity and regulation. These data strongly suggest that heterodimerization between PDK1 and PDK2 adds another level of diversity to this protein family in addition to that which arises from gene multiplicity.
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structure of Pyruvate Dehydrogenase Kinase novel folding pattern for a serine protein Kinase
Journal of Biological Chemistry, 2001Co-Authors: Nicklaus C Steussy, Kirill M. Popov, Robert A Harris, Melissa M Bowkerkinley, Robert B Sloan, Jean A HamiltonAbstract:Abstract The structure of mitochondrial Pyruvate Dehydrogenase Kinase isozyme 2 is of interest because it represents a family of serine-specific protein Kinases that lack sequence similarity with all other eukaryotic protein Kinases. Similarity exists instead with key motifs of prokaryotic histidine protein Kinases and a family of eukaryotic ATPases. The 2.5-A crystal structure reported here reveals that Pyruvate Dehydrogenase Kinase isozyme 2 has two domains of about the same size. The N-terminal half is dominated by a bundle of four amphipathic α-helices, whereas the C-terminal half is folded into an α/β sandwich that contains the nucleotide-binding site. Analysis of the structure reveals this C-terminal domain to be very similar to the nucleotide-binding domain of bacterial histidine Kinases, but the catalytic mechanism appears similar to that of the eukaryotic serine Kinases and ATPases.
