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miR-141/200c contributes to ethanol-mediated hepatic glycogen metabolism. Mol Metab 2024; 84:101942. [PMID: 38642890 PMCID: PMC11060962 DOI: 10.1016/j.molmet.2024.101942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 04/15/2024] [Indexed: 04/22/2024] Open
Abstract
OBJECTIVE Hepatic glucose metabolism is profoundly perturbed by excessive alcohol intake. miR-141/200c expression is significantly induced by chronic ethanol feeding. This study aimed at identifying the role of miR-141/200c in glucose homeostasis during chronic ethanol exposure. METHODS WT and miR-141/200c KO mice were fed a control or an ethanol diet for 30 days, followed by a single binge of maltose dextrin or ethanol, respectively. Untargeted metabolomics analysis of hepatic primary metabolites was performed along with analyses for liver histology, gene expression, intracellular signaling pathways, and physiological relevance. Primary hepatocytes were used for mechanistic studies. RESULTS miR-141/200c deficiency rewires hepatic glucose metabolism during chronic ethanol feeding, increasing the abundance of glucose intermediates including G6P, an allosteric activator for GS. miR-141/200c deficiency replenished glycogen depletion during chronic ethanol feeding accompanied by reduced GS phosphorylation in parallel with increased expression of PP1 glycogen targeting subunits. Moreover, miR-141/200c deficiency prevented ethanol-mediated increases in AMPK and CaMKK2 activity. Ethanol treatment reduced glycogen content in WT-hepatocytes, which was reversed by dorsomorphin, a selective AMPK inhibitor, while KO-hepatocytes displayed higher glycogen content than WT-hepatocytes in response to ethanol treatment. Furthermore, treatment of hepatocytes with A23187, a calcium ionophore activating CaMKK2, lowered glycogen content in WT-hepatocytes. Notably, the suppressive effect of A23187 on glycogen deposition was reversed by dorsomorphin, demonstrating that the glycogen depletion by A23187 is mediated by AMPK. KO-hepatocytes exhibited higher glycogen content than WT-hepatocytes in response to A23187. Finally, miR-141/200c deficiency led to improved glucose tolerance and insulin sensitivity during chronic ethanol feeding. CONCLUSIONS miR-141/200c deficiency replenishes ethanol-mediated hepatic glycogen depletion through the regulation of GS activity and calcium signaling coupled with the AMPK pathway, improving glucose homeostasis and insulin sensitivity. These results underscore miR-141/200c as a potential therapeutic target for the management of alcohol intoxication.
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SerpinA3N deficiency attenuates steatosis and enhances insulin signaling in male mice. J Endocrinol 2023; 256:e220073. [PMID: 36625462 PMCID: PMC9930402 DOI: 10.1530/joe-22-0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 01/10/2023] [Indexed: 01/11/2023]
Abstract
Aberrant hepatic lipid metabolism is the major cause of non-alcoholic fatty liver disease (NAFLD) and is associated with insulin resistance and type 2 diabetes. Serine (or cysteine) peptidase inhibitor, clade A, member 3N (SerpinA3N) is highly expressed in the liver; however, its functional role in regulating NAFLD and associated metabolic disorders are not known. Male wildtype and hepatocyte Serpina3N knockout (HKO) mice were fed a control diet, methionine- and choline-deficient diet or high-fat high-sucrose diet to induce NAFLD and markers of lipid metabolism and glucose homeostasis were assessed. SerpinA3N protein was markedly induced in mice with fatty livers. Hepatic deletion of SerpinA3N attenuated steatosis which correlated with altered lipid metabolism genes, increased fatty acid oxidation activity and enhanced insulin signaling in mice with NAFLD. Additionally, SerpinA3N HKO mice had reduced epididymal white adipose tissue mass, leptin, and insulin levels, improved glucose tolerance, and enhanced insulin sensitivity which was associated with elevated insulin-like growth factor binding protein-1 (IGFBP1) and activation of the leptin receptor (LEPR)-STAT3 signaling pathway. Our findings provide a novel insight into the functional role of SerpinA3N in regulating NAFLD and glucose homeostasis.
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The Novel Hooked Kirschner Wire Technique for Ulna Coronoid Process Fractures. Clin Orthop Surg 2023; 15:127-134. [PMID: 36778994 PMCID: PMC9880501 DOI: 10.4055/cios22148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/11/2022] [Accepted: 07/11/2022] [Indexed: 11/05/2022] Open
Abstract
Background The aim of this study was to introduce a novel technique to improve the ease of fixing of even small fragments of the coronoid process and report the clinical outcomes of this method. Methods Forty-nine patients with ulnar coronoid process fractures fixed using the hooked Kirschner wire (K-wire) technique at our hospital from 2007 to 2019 were reviewed. Radiological features and fracture union were assessed using simple radiographs. Functional outcomes of the treated elbows were evaluated at the final follow-up visit using the Mayo Elbow Performance Score (MEPS). Results All patients were examined at a mean follow-up of 17.7 months (range, 6-62 months). We observed bony union in patients at a mean of 10.9 weeks (range, 6-22 weeks). The mean flexion and extension ranges of the elbow were 132.0° (range, 106° -151°) and 4.5° (range, -20° to 30°), respectively. The mean pronation and supination ranges of the forearm were 81.1° (range, 60°-90°) and 88.3° (range, 60°-120°), respectively. The mean arc of the elbow was 127.4° (range, 78°-160°). All patients were evaluated using the MEPS at the final follow-up visit, with a mean score of 96.9 points (range, 80-100 points). One case of coronoid nonunion was observed and re-fixation was performed. One case of infection was observed and also treated with additional surgery. Three patients complained of ulnar nerve symptoms and 1 patient underwent surgical release for tardy ulnar nerve palsy. Conclusions Despite its limitations, the hooked K-wire technique was a useful method for even smaller coronoid process fractures. K-wires were also a useful temporary intraoperative fixation method and could provide permanent fixation.
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MicroRNA-200c coordinates HNF1 homeobox B and apolipoprotein O functions to modulate lipid homeostasis in alcoholic fatty liver disease. J Biol Chem 2022; 298:101966. [PMID: 35460694 PMCID: PMC9127369 DOI: 10.1016/j.jbc.2022.101966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 02/04/2023] Open
Abstract
Hepatic steatosis is an initial manifestation of alcoholic liver disease. An imbalance of hepatic lipid processes including fatty acid uptake, esterification, oxidation, and triglyceride secretion leads to alcoholic fatty liver (AFL). However, the precise molecular mechanisms underlying the pathogenesis of AFL remain elusive. Here, we show that mice deficient in microRNAs (miRs)-141 and -200c display resistance to the development of AFL. We found that miR-200c directly targets HNF1 homeobox B (Hnf1b), a transcriptional activator for microsomal triglyceride transfer protein (Mttp), as well as apolipoprotein O (ApoO), an integral component of the mitochondrial contact site and cristae organizing system complex. We show that expression of these miRs is significantly induced by chronic ethanol exposure, which is accompanied by reduced HNF1B and APOO levels. Furthermore, miR-141/200c deficiency normalizes ethanol-mediated impairment of triglyceride secretion, which can be attributed to the restored levels of HNF1B and MTTP, as well as phosphatidylcholine abundance. Moreover, we demonstrate that miR-141/200c deficiency restores ethanol-mediated inhibition of APOO expression and mitochondrial dysfunction, improving mitochondrial antioxidant defense capacity and fatty acid oxidation. Taken together, these results suggest that miR-200c contributes to the modulation of lipid homeostasis in AFL disease by cooperatively regulating Hnf1b and ApoO functions.
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Abstract
Background: The risk of cardiovascular disease in type 1 diabetes remains extremely high, despite marked advances in blood glucose control and even the widespread use of cholesterol synthesis inhibitors. Thus, a deeper understanding of insulin regulation of cholesterol metabolism, and its disruption in type 1 diabetes, could reveal better treatment strategies. Methods: To define the mechanisms by which insulin controls plasma cholesterol levels, we knocked down the insulin receptor, FoxO1, and the key bile acid synthesis enzyme, CYP8B1. We measured bile acid composition, cholesterol absorption, and plasma cholesterol. In parallel, we measured markers of cholesterol absorption and synthesis in humans with type 1 diabetes treated with ezetimibe and statins in a double-blind crossover study. Results: Mice with hepatic deletion of the insulin receptor showed marked increases in 12α-hydroxylated bile acids (12HBAs), cholesterol absorption, and plasma cholesterol. This phenotype was entirely reversed by hepatic deletion of FoxO1. FoxO1 is inhibited by insulin, and required for the production of 12HBAs, which promote intestinal cholesterol absorption and suppress hepatic cholesterol synthesis. Knockdown of Cyp8b1 normalized 12HBA levels and completely prevented hypercholesterolemia in mice with hepatic deletion of the insulin receptor (n=5-30) as well as mouse models of type 1 diabetes (n=5-22). In parallel, the cholesterol absorption inhibitor, ezetimibe, normalized cholesterol absorption and LDL-cholesterol in patients with type 1 diabetes as well as, or better than, the cholesterol synthesis inhibitor, simvastatin (n=20). Conclusions: Insulin, by inhibiting FoxO1 in the liver, reduces 12HBAs, cholesterol absorption, and plasma cholesterol levels. Thus, type 1 diabetes leads to a unique set of derangements in cholesterol metabolism, with increased absorption rather than synthesis. These derangements are reversed by ezetimibe, but not statins, which are currently the first line of lipid-lowering treatment in type 1 diabetes. Taken together, these data suggest that a personalized approach to lipid lowering in type 1 diabetes may be more effective and highlight the need for further studies specifically in this group of patients.
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MiR-200c-3p targets SESN1 and represses the IL-6/AKT loop to prevent cholangiocyte activation and cholestatic liver fibrosis. J Transl Med 2022; 102:485-493. [PMID: 34880414 PMCID: PMC9042705 DOI: 10.1038/s41374-021-00710-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 01/06/2023] Open
Abstract
Cholestasis causes ductular reaction in the liver where the reactive cholangiocytes not only proliferate but also gain a neuroendocrine-like phenotype, leading to inflammatory cell infiltration and extracellular matrix deposition and contributing to the development and progression of cholestatic liver fibrosis. This study aims to elucidate the role of miR-200c in cholestasis-induced biliary liver fibrosis and cholangiocyte activation. We found that miR-200c was extremely abundant in cholangiocytes but was reduced by cholestasis in a bile duct ligation (BDL) mouse model; miR-200c was also decreased by bile acids in vitro. Phenotypically, loss of miR-200c exacerbated cholestatic liver injury, including periductular fibrosis, intrahepatic inflammation, and biliary hyperplasia in both the BDL model and the 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) model. We identified sestrin 1 (SESN1) as a target of miR-200c. Sesn1-/--BDL mice showed mitigation of cholestatic liver injury. On a molecular level, the pro-proliferative IL-6/AKT feedback loop was activated in Mir200c-/- livers but was inhibited in Sesn1-/- livers upon cholestasis in mice. Furthermore, rescuing expression of miR-200c by the adeno-associated virus serotype 8 ameliorated BDL-induced liver injury in Mir200c-/- mice. Taken together, this study demonstrates that miR-200c restrains the proliferative and neuroendocrine-like activation of cholangiocytes by targeting SESN1 and inhibiting the IL-6/AKT feedback loop to protect against cholestatic liver fibrosis. Our findings provide mechanistic insights regarding biliary liver fibrosis, which may help to reveal novel therapeutic targets for the treatment of cholestatic liver injury and liver fibrosis.
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A Potential Role for SerpinA3N in Acetaminophen-Induced Hepatotoxicity. Mol Pharmacol 2021; 99:277-285. [PMID: 33436521 DOI: 10.1124/molpharm.120.000117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/31/2020] [Indexed: 10/25/2022] Open
Abstract
Acetaminophen (APAP) is a commonly used pain and fever reliever but is also the most frequent cause of drug-induced liver injury. The mechanism pertaining acetaminophen toxicity has been well documented, whereas mechanisms of hepatotoxicity are not well established. Serine (or cysteine) peptidase inhibitor, clade A, member 3N (SerpinA3N), a serine protease inhibitor, is synthesized in the liver but the role of SerpinA3N in relation to APAP-induced liver injury is not known. Wild-type and hepatocyte-specific SerpinA3N knockout (HKO) mice were injected intraperitoneally with a single dose of PBS or APAP (400 mg/kg) for 12 hours, and markers of liver injury, cell death, and inflammation were assessed. SerpinA3N expression was highly induced in mice with APAP overdose. SerpinA3N HKO mice had diminished liver injury and necrosis as shown by lower alanine aminotransferase and interleukin-6 levels, accompanied by suppressed inflammatory cytokines and reduced neutrophil infiltration. The reduced oxidative stress was associated with enhanced antioxidant enzyme capabilities. Taken together, hepatocyte SerpinA3N deficiency reduced APAP-induced liver injury by ameliorating inflammation and modulating the 5' AMP-activated protein kinase-unc-51-like autophagy activating kinase 1 signaling pathway. Our study provides novel insights into a potential role for SerpinA3N in APAP-induced liver injury. SIGNIFICANCE STATEMENT: Our studies indicate that serine (or cysteine) peptidase inhibitor, clade A, member 3N (SerpinA3N) may have a pathophysiological role in modulating acetaminophen (APAP)-induced liver injury. More specifically, mice with hepatic deletion of SerpinA3N suppressed inflammation and liver injury to reduce APAP-induced hepatotoxicity. Controlling the inflammatory response offers possible approaches for novel therapeutics; therefore, understanding the pathophysiological role of SerpinA3N in inducing liver injury may add to the development of more efficacious treatments.
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PDK4-Deficiency Reprograms Intrahepatic Glucose and Lipid Metabolism to Facilitate Liver Regeneration in Mice. Hepatol Commun 2020; 4:504-517. [PMID: 32258946 PMCID: PMC7109344 DOI: 10.1002/hep4.1484] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/10/2020] [Indexed: 12/29/2022] Open
Abstract
Liver regeneration requires intrahepatic and extrahepatic metabolic reprogramming to meet the high hepatic bioenergy demand for liver cell repopulation. This study aims to elucidate how pyruvate dehydrogenase kinase 4 (PDK4), a critical regulator of glucose and lipid metabolism, coordinates metabolic regulation with efficient liver growth. We found that hepatic Pdk4 expression was elevated after two-thirds partial hepatectomy (PHx). In Pdk4 -/- PHx mice, the liver/body weight ratio was more rapidly restored, accompanied by more aggressive hepatic DNA replication; however, Pdk4 -/- mice developed more severe hypoglycemia. In Pdk4 -/- PHx livers, the pro-regenerative insulin signaling was potentiated, as demonstrated by early peaking of the phosphorylation of insulin receptor, more remarkable induction of the insulin receptor substrate proteins, IRS1 and IRS2, and more striking activation of Akt. The hepatic up-regulation of CD36 contributed to the enhanced transient regeneration-associated steatosis in Pdk4 -/- PHx mice. Notably, CD36 overexpression in mice promoted the recovery of liver/body weight ratio and elevated intrahepatic adenosine triphosphate after PHx. CD36 expression was transcriptionally suppressed by FOXO1 (forkhead box protein O1), which was stabilized and translocated to the nucleus following AMPK (adenosine monophosphate-activated protein kinase) activation. PHx remarkably induced AMPK activation, which became incompetent to respond in Pdk4 -/- livers. Moreover, we defined that PDK4-regulated AMPK activation directly depended on intracellular adenosine monophosphate in vitro and in regenerative livers. Conclusion: PDK4 inhibition reprograms glucose and lipid metabolism to promote liver regeneration by enhancing hepatic insulin/Akt signaling and activating an AMPK/FOXO1/CD36 regulatory axis of lipid. These findings may lead to potential therapeutic strategies to prevent hepatic insufficiency and liver failure.
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Genome-Wide Analysis for Identifying FOXO Protein-Binding Sites. Methods Mol Biol 2019; 1890:193-203. [PMID: 30414155 DOI: 10.1007/978-1-4939-8900-3_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Forkhead box O (FOXO) proteins comprise a superfamily of transcription factors that play important roles in controlling various biological processes. Transcriptional control constitutes a crucial component in regulating complex biological processes. The identification of cis-regulatory elements is essential to understand the regulatory mechanism of gene expression. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) is widely used to identify the cis-regulatory elements of transcription factors and other DNA-binding proteins on a genome-wide level. It is a powerful tool to analyze the regulatory networks underlying the biological processes. Here, we describe a detailed protocol for preparing ChIP-seq samples that are used for sequencing and subsequent data analyses.
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Application of 3D Fast Spin-Echo T1 Black-Blood Imaging in the Diagnosis and Prognostic Prediction of Patients with Leptomeningeal Carcinomatosis. AJNR Am J Neuroradiol 2018; 39:1453-1459. [PMID: 30002052 DOI: 10.3174/ajnr.a5721] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/23/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Contrast-enhanced 3D fast spin-echo T1 black-blood imaging selectively suppresses the signal of blood flow and could provide a higher contrast-to-noise ratio compared with contrast-enhanced 3D ultrafast gradient recalled echo (contrast-enhanced gradient recalled echo) and 2D spin-echo T1WI (contrast-enhanced spin-echo). The purpose of our study was to evaluate whether black-blood imaging can improve the diagnostic accuracy for leptomeningeal carcinomatosis compared with contrast-enhanced gradient recalled-echo and contrast-enhanced spin-echo and, furthermore, to determine whether the grade of leptomeningeal carcinomatosis evaluated on black-blood imaging is a significant predictor of progression-free survival. MATERIALS AND METHODS Leptomeningeal carcinomatosis (n = 78) and healthy (n = 31) groups were enrolled. Contrast-enhanced gradient recalled-echo, contrast-enhanced spin-echo, and black-blood imaging were separately reviewed, and a diagnostic rating (positive, indeterminate, or negative) and grading of leptomeningeal carcinomatosis were assigned. The diagnostic accuracies of the 3 imaging sequences were compared in terms of leptomeningeal carcinomatosis detection. The Kaplan-Meier and the Cox proportional hazards model analyses were performed to determine the relationship between the leptomeningeal carcinomatosis grade evaluated on black-blood imaging and progression-free survival. RESULTS Black-blood imaging showed a significantly higher sensitivity (97.43%) than contrast-enhanced gradient recalled-echo (64.1%) and contrast-enhanced spin-echo (66.67%) (P < .05). In terms of specificities, we did not find any significant differences among contrast-enhanced gradient recalled-echo (90.32%), contrast-enhanced spin-echo (90.32%), and black-blood imaging (96.77%) (P > .05). A Cox proportional hazards model identified the time to metastasis, Karnofsky Performance Scale status, and a combination of the leptomeningeal carcinomatosis grade with a linear pattern as independent predictors of progression-free survival (P < .05). CONCLUSIONS Black-blood imaging can improve the diagnostic accuracy and predict progression-free survival in patients with leptomeningeal carcinomatosis.
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Long noncoding RNA H19 interacts with polypyrimidine tract-binding protein 1 to reprogram hepatic lipid homeostasis. Hepatology 2018; 67:1768-1783. [PMID: 29140550 PMCID: PMC5906152 DOI: 10.1002/hep.29654] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/08/2017] [Accepted: 11/09/2017] [Indexed: 12/13/2022]
Abstract
UNLABELLED H19 is an imprinted long noncoding RNA abundantly expressed in embryonic liver and repressed after birth. We show that H19 serves as a lipid sensor by synergizing with the RNA-binding polypyrimidine tract-binding protein 1 (PTBP1) to modulate hepatic metabolic homeostasis. H19 RNA interacts with PTBP1 to facilitate its association with sterol regulatory element-binding protein 1c mRNA and protein, leading to increased stability and nuclear transcriptional activity. H19 and PTBP1 are up-regulated by fatty acids in hepatocytes and in diet-induced fatty liver, which further augments lipid accumulation. Ectopic expression of H19 induces steatosis and pushes the liver into a "pseudo-fed" state in response to fasting by promoting sterol regulatory element-binding protein 1c protein cleavage and nuclear translocation. Deletion of H19 or knockdown of PTBP1 abolishes high-fat and high-sucrose diet-induced steatosis. CONCLUSION Our study unveils an H19/PTBP1/sterol regulatory element-binding protein 1 feedforward amplifying signaling pathway to exacerbate the development of fatty liver. (Hepatology 2018;67:1768-1783).
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FoxO1 Is Required for Most of the Metabolic and Hormonal Perturbations Produced by Hepatic Insulin Receptor Deletion in Male Mice. Endocrinology 2018; 159:1253-1263. [PMID: 29300910 PMCID: PMC5802805 DOI: 10.1210/en.2017-00870] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/21/2017] [Indexed: 12/16/2022]
Abstract
Insulin coordinates the complex response to feeding, affecting numerous metabolic and hormonal pathways. Forkhead box protein O1 (FoxO1) is one of several signaling molecules downstream of insulin; FoxO1 drives gluconeogenesis and is suppressed by insulin. To determine the role of FoxO1 in mediating other actions of insulin, we studied mice with hepatic deletion of the insulin receptor, FoxO1, or both. We found that mice with deletion of the insulin receptor alone showed not only hyperglycemia but also a 70% decrease in plasma insulin-like growth factor 1 and delayed growth during the first 2 months of life, a 24-fold increase in the soluble leptin receptor and a 19-fold increase in plasma leptin levels. Deletion of the insulin receptor also produced derangements in fatty acid metabolism, with a decrease in the expression of the lipogenic enzymes, hepatic diglycerides, and plasma triglycerides; in parallel, it increased expression of the fatty acid oxidation enzymes. Mice with deletion of both insulin receptor and FoxO1 showed a much more modest phenotype, with normal or near-normal glucose levels, growth, leptin levels, hepatic diglycerides, and fatty acid oxidation gene expression; however, lipogenic gene expression remained low. Taken together, these data reveal the pervasive role of FoxO1 in mediating the effects of insulin on not only glucose metabolism but also other hormonal signaling pathways and even some aspects of lipid metabolism.
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YAP suppresses gluconeogenic gene expression through PGC1α. Hepatology 2017; 66:2029-2041. [PMID: 28714135 PMCID: PMC6082140 DOI: 10.1002/hep.29373] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/25/2017] [Accepted: 07/12/2017] [Indexed: 12/19/2022]
Abstract
UNLABELLED Cell growth and proliferation are tightly coupled to metabolism, and dissecting the signaling molecules which link these processes is an important step toward understanding development, regeneration, and cancer. The transcriptional regulator Yes-associated protein 1 (YAP) is a key regulator of liver size, development, and function. We now show that YAP can also suppress gluconeogenic gene expression. Yap deletion in primary hepatocytes potentiates the gluconeogenic gene response to glucagon and dexamethasone, whereas constitutively active YAP suppresses it. The effects of YAP are mediated by the transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator 1. YAP inhibits its ability to bind to and activate transcription from the promoters of its gluconeogenic targets, and the effects of YAP are blunted upon its knockdown. In vivo, constitutively active YAP lowers plasma glucose levels and increases liver size. CONCLUSION YAP appears to reprogram cellular metabolism, diverting substrates away from the energy-consuming process of gluconeogenesis and toward the anabolic process of growth. (Hepatology 2017;66:2029-2041).
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Loss of miR-141/200c ameliorates hepatic steatosis and inflammation by reprogramming multiple signaling pathways in NASH. JCI Insight 2017; 2:96094. [PMID: 29093267 DOI: 10.1172/jci.insight.96094] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/26/2017] [Indexed: 12/12/2022] Open
Abstract
Accumulation of lipid droplets and inflammatory cell infiltration is the hallmark of nonalcoholic steatohepatitis (NASH). The roles of noncoding RNAs in NASH are less known. We aim to elucidate the function of miR-141/200c in diet-induced NASH. WT and miR-141/200c-/- mice were fed a methionine and choline deficient (MCD) diet for 2 weeks to assess markers of steatosis, liver injury, and inflammation. Hepatic miR-141 and miR-200c RNA levels were highly induced in human patients with NASH fatty liver and in WT MCD mice. miR-141/200c-/- MCD mice had reduced liver weights and triglyceride (TG) levels, which was associated with increased microsomal TG transfer protein (MTTP) and PPARα but reduced SREBP1c and FAS expression. Inflammation was attenuated and F4/80 macrophage activation was suppressed in miR-141/200c-/- mice, as evidenced by decreased serum aminotransferases and IL-6 and reduced hepatic proinflammatory, neutrophil, and profibrotic genes. Treatment with LPS in BM-derived macrophages isolated from miR-200c/141-/- mice polarized macrophages toward the M2 antiinflammatory state by increasing Arg1 and IL-10 levels while decreasing the M1 marker iNOS. In addition, elevated phosphorylated AMPK (p-AMPK), p-AKT, and p-GSK3β and diminished TLR4 and p-mTOR/p-4EBP1 proteins were observed. Lipidomics and metabolomics revealed alterations of TG and phosphatidylcholine (PC) lipid species by miR-141/200c deficiency. In summary, miR-141/200c deficiency diminished NASH-associated hepatic steatosis and inflammation by reprogramming lipid and inflammation signaling pathways.
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Mobile nucleic acid amplification testing (mobiNAAT) for Chlamydia trachomatis screening in hospital emergency department settings. Sci Rep 2017; 7:4495. [PMID: 28674410 PMCID: PMC5495747 DOI: 10.1038/s41598-017-04781-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 05/22/2017] [Indexed: 11/30/2022] Open
Abstract
Management of curable sexually-transmitted infections (STI) such as Chlamydia can be revolutionized by highly sensitive nucleic acid testing that is deployable at the point-of-care (POC). Here we report the development of a mobile nucleic acid amplification testing (mobiNAAT) platform utilizing a mobile phone and droplet magnetofluidics to deliver NAAT in a portable and accessible format. By using magnetic particles as a mobile substrate for nucleic acid capture and transport, fluid handling is reduced to particle translocation on a simple magnetofluidic cartridge assembled with reagents for nucleic acid purification and amplification. A mobile phone user interface operating in tandem with a portable Bluetooth-enabled cartridge-processing unit facilitates process integration. We tested 30 potentially Chlamydia trachomatis (CT)-infected patients in a hospital emergency department and confirmed that mobiNAAT showed 100% concordance with laboratory-based NAAT. Concurrent evaluation by a nontechnical study coordinator who received brief training via an embedded mobile app module demonstrated ease of use and reproducibility of the platform. This work demonstrates the potential of mobile nucleic acid testing in bridging the diagnostic gap between centralized laboratories and hospital emergency departments.
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Comparison of short wrist transverse open and limited open techniques for carpal tunnel release: a randomized controlled trial of two incisions. J Hand Surg Eur Vol 2016; 41:143-7. [PMID: 26353946 DOI: 10.1177/1753193415603968] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 07/10/2015] [Indexed: 02/03/2023]
Abstract
UNLABELLED The purpose of this randomized controlled trial was to compare outcomes of limited open and short wrist transverse techniques in patients with carpal tunnel syndrome. In a single centre randomized controlled trial, 84 patients with idiopathic carpal tunnel syndrome were randomized before surgery to limited open or short wrist transverse open carpal tunnel release. The patients were evaluated at 6 weeks, 3 months, 6 months, and 1 and 2 years after surgery. At every follow-up, the Brigham and Women's Carpal Tunnel Questionnaire scores, scar discomfort, and subjective patient satisfaction were evaluated. Two years after surgery, five patients were lost to follow-up. The groups had similar Brigham and Women's Carpal Tunnel Questionnaire Symptom Severity and Functional Status scores and subjective satisfaction scores. The incidence of scar discomfort was not significantly different between the two groups on serial postoperative follow-up. Short wrist transverse open release surgery showed similar early postoperative symptoms and subjective and functional outcomes to limited open release. LEVEL OF EVIDENCE II.
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Comparison of short wrist transverse open and limited open techniques for carpal tunnel release: a randomized controlled trial of two incisions. THE JOURNAL OF HAND SURGERY, EUROPEAN VOLUME 2015. [PMID: 26353946 DOI: 10.1177/1753193415603968.] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED The purpose of this randomized controlled trial was to compare outcomes of limited open and short wrist transverse techniques in patients with carpal tunnel syndrome. In a single centre randomized controlled trial, 84 patients with idiopathic carpal tunnel syndrome were randomized before surgery to limited open or short wrist transverse open carpal tunnel release. The patients were evaluated at 6 weeks, 3 months, 6 months, and 1 and 2 years after surgery. At every follow-up, the Brigham and Women's Carpal Tunnel Questionnaire scores, scar discomfort, and subjective patient satisfaction were evaluated. Two years after surgery, five patients were lost to follow-up. The groups had similar Brigham and Women's Carpal Tunnel Questionnaire Symptom Severity and Functional Status scores and subjective satisfaction scores. The incidence of scar discomfort was not significantly different between the two groups on serial postoperative follow-up. Short wrist transverse open release surgery showed similar early postoperative symptoms and subjective and functional outcomes to limited open release. LEVEL OF EVIDENCE II.
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002.6 A low-cost mobile naat platform for chlamydia trachomatis. Br J Vener Dis 2015. [DOI: 10.1136/sextrans-2015-052270.90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Role of Insulin in the Regulation of Proprotein Convertase Subtilisin/Kexin Type 9. Arterioscler Thromb Vasc Biol 2015; 35:1589-96. [PMID: 26023080 DOI: 10.1161/atvbaha.115.305688] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Proprotein convertase subtilisin/kexin type 9 (PCSK9), which binds the low-density lipoprotein receptor and targets it for degradation, has emerged as an important regulator of serum cholesterol levels and cardiovascular disease risk. Although much work is currently focused on developing therapies for inhibiting PCSK9, the endogenous regulation of PCSK9, particularly by insulin, remains unclear. The objective of these studies was to determine the effects of insulin on PCSK9 in vitro and in vivo. APPROACH AND RESULTS Using rat hepatoma cells and primary rat hepatocytes, we found that insulin increased PCSK9 expression and increased low-density lipoprotein receptor degradation in a PCSK9-dependent manner. In parallel, hepatic Pcsk9 mRNA and plasma PCSK9 protein levels were reduced by 55% to 75% in mice with liver-specific knockout of the insulin receptor; 75% to 88% in mice made insulin-deficient with streptozotocin; and 65% in ob/ob mice treated with antisense oligonucleotides against the insulin receptor. However, antisense oligonucleotide-mediated knockdown of insulin receptor in lean, wild-type mice had little effect. In addition, we found that fasting was able to reduce PCSK9 expression by 80% even in mice that lack hepatic insulin signaling. CONCLUSIONS Taken together, these data indicate that although insulin induces PCSK9 expression, it is not the sole or even dominant regulator of PCSK9 under all conditions.
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An Anterosuperior Deltoid Splitting Approach for Plate Fixation of Proximal Humeral Fractures. Clin Shoulder Elb 2015. [DOI: 10.5397/cise.2015.18.1.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Imbalance between neutrophil elastase and its inhibitor α1-antitrypsin in obesity alters insulin sensitivity, inflammation, and energy expenditure. Cell Metab 2013; 17:534-48. [PMID: 23562077 PMCID: PMC3646573 DOI: 10.1016/j.cmet.2013.03.005] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 01/02/2013] [Accepted: 03/11/2013] [Indexed: 12/15/2022]
Abstract
The molecular mechanisms involved in the development of obesity and related complications remain unclear. Here, we report that obese mice and human subjects have increased activity of neutrophil elastase (NE) and decreased serum levels of the NE inhibitor α1-antitrypsin (A1AT, SerpinA1). NE null (Ela2(-/-)) mice and A1AT transgenic mice were resistant to high-fat diet (HFD)-induced body weight gain, insulin resistance, inflammation, and fatty liver. NE inhibitor GW311616A reversed insulin resistance and body weight gain in HFD-fed mice. Ela2(-/-) mice also augmented circulating high molecular weight (HMW) adiponectin levels, phosphorylation of AMP-activated protein kinase (AMPK), and fatty acid oxidation (FAO) in the liver and brown adipose tissue (BAT) and uncoupling protein (UCP1) levels in the BAT. These data suggest that the A1AT-NE system regulates AMPK signaling, FAO, and energy expenditure. The imbalance between A1AT and NE contributes to the development of obesity and related inflammation, insulin resistance, and liver steatosis.
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Development of a droplet-vitrification protocol for cryopreservation of Rubia akane (Nakai) hairy roots using a systematic approach. CRYO LETTERS 2012; 33:506-517. [PMID: 23250410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A systematic approach using a set of 13 treatments was applied to develop a droplet-vitrification protocol for Rubia akane hairy roots, based on their responses to preculture, loading, dehydration and cooling/rewarming steps. The roots were very sensitive to osmotic stress induced by both preculture in liquid sucrose-enriched medium (up to 0.5 M sucrose) and by dehydration with highly concentrated vitrification solutions (VSs). Loading was necessary before dehydration of explants with VS, and the composition of the loading solution (LS) significantly affected their post-cryopreservation regeneration. Due to high sensitivity of roots to both chemical cytotoxicity and osmotic stress produced by VSs, cryoprotection with alternative VSs, i.e. B5-80 percent (40 percent glycerol + 40 percent sucrose, w/v) at room temperature for 15 min or with A3-70 percent (29.2 percent glycerol + 11.7 percent DMSO + 11.7 percent EG + 17.4 percent sucrose, w/v) at 0 degree C for 20 min ensured the highest post-cryopreservation regeneration. However, when using these solutions, endothermic peaks (enthalpies) with -2.9 and -5.8 J per gram fresh weight, respectively, were recorded by differential scanning calorimetry (DSC) during the rewarming phase. Droplet-vitrification using foil strips showed higher post-cryopreservation regeneration (86 percent) compared with vitrification in cryovials (59 percent), possibly due to the higher cooling and rewarming rates achieved with droplet-vitrification. The developed protocol was applied to hairy roots of five other species with minor modifications in explant type, the duration of the last subculture before explant excision, and the dehydration duration with VS B5-80 percent.
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Genome-wide analysis of FoxO1 binding in hepatic chromatin: potential involvement of FoxO1 in linking retinoid signaling to hepatic gluconeogenesis. Nucleic Acids Res 2012; 40:11499-509. [PMID: 23066095 PMCID: PMC3526316 DOI: 10.1093/nar/gks932] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The forkhead transcription factor FoxO1 is a critical regulator of hepatic glucose and lipid metabolism, and dysregulation of FoxO1 function has been implicated in diabetes and insulin resistance. We globally identified FoxO1 occupancy in mouse hepatic chromatin on a genome-wide level by chromatin immunoprecipitation coupled with high-throughput DNA sequencing (ChIP-seq). To establish the specific functional significance of FoxO1 against other FoxO proteins, ChIP-seq was performed with chromatin from liver-specific FoxO1 knockout and wild-type mice. Here we identified 401 genome-wide FoxO1-binding locations. Motif search reveals a sequence element, 5′ GTAAACA 3′, consistent with a previously known FoxO1-binding site. Gene set enrichment analysis shows that the data from FoxO1 ChIP-seq are highly correlated with the global expression profiling of genes regulated by FoxO1, demonstrating the functional relevance of our FoxO1 ChIP-seq study. Interestingly, gene ontology analysis reveals the functional significance of FoxO1 in retinoid metabolic processes. We show here that FoxO1 directly binds to the genomic sites for the genes in retinoid metabolism. Notably, deletion of FoxO1 caused a significantly reduced induction of Pck1 and Pdk4 in response to retinoids. As Pck1 and Pdk4 are downstream targets of retinoid signaling, these results suggest that FoxO1 plays a potential role in linking retinoid metabolism to hepatic gluconeogenesis.
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Cryopreservation of Kalopanax septemlobus embryogenic callus using vitrification and droplet-vitrification. CRYO LETTERS 2012; 33:402-410. [PMID: 23224373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A cryopreservation protocol has been developed for embryogenic callus cultures of castor aralia (Kalopanax septemlobus), a deciduous tree which is widely used in oriental medicine and in landscape design. Three preculture treatments, four loading and six vitrification solutions were tested in a vitrification procedure. Preculture of embryogenic callus (EC) with high sucrose concentrations (up to 0.7 M) showed no effect on regrowth after cryopreservation. Loading for 20 min at ambient temperature improved regrowth of cryopreserved EC by 70-75 percent compared with non-loaded samples, regardless of the composition of the loading solution. Among vitrification solutions, the highest regrowth of 95-100 percent after cryopreservation was obtained after incubation of EC in a vitrification solution A3-80 percent comprising (w/v) 33.3 percent glycerol + 13.3 percent DMSO + 13.3 percent EG + 20.1 percent sucrose for 40 min at 0°C. Profiling of crystallization and recrystallization events using differential scanning calorimetry (DSC) confirmed that freezing injury was minimized in samples after loading and cryoprotection with this vitrification solution. Unlike many other papers, the droplet-vitrification protocol did not produce higher post-cryopreservation regrowth of Kalopanax EC, compared with the vitrification procedure. When samples are sufficiently cryoprotected during VS treatment, vitrification using cryovials may be preferred, since droplet-vitrification is more complex and requires skilled personnel. Cryopreserved callus grew rapidly and produced numerous somatic embryos, which developed similarly to embryos obtained from non-cryopreserved samples.
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Cryobanking of Korean allium germplasm collections: results from a 10 year experience. CRYO LETTERS 2012; 33:45-57. [PMID: 22434122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper reviews a 10-year experience in establishing a cryopreserved Allium germplasm collection at the genebank of the National Agrobiodiversity Center, Republic of Korea. A systematic approach to Allium cryopreservation included: 1. revealing the most critical factors that affected regeneration after cryostorage; 2. understanding the mechanisms of cryoprotection by analyzing the thermal behavior of explants and cryoprotectant solutions using DSC and influx/efflux of cryoprotectants using HPLC; 3. assessing genetic stability of regenerants; and 4. revealing the efficiency of cryotherapy. Bulbil primordia, i.e. asexual bulbs formed on unripe inflorescences, proved to be the most suitable material for conservation of bolting varieties due to high post-cryopreservation regrowth and lower microbial infection level, followed by apical shoot apices from single bulbs and cloves. A total of 1,158 accessions of garlic as well as some Allium species have been cryopreserved during 2005-2010 using the droplet-vitrification technique with a mean regeneration percentage of 65.9 percent after cryostorage. These results open the door for large-scale implementation of cryostorage and for simplifying international exchange for clonal Allium germplasm.
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Pyogenic Arthritis of the Shoulder in Patient with Infective Endocarditis -A Case Report-. Clin Shoulder Elb 2010. [DOI: 10.5397/cise.2010.13.1.106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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FGF15/FGFR4 integrates growth factor signaling with hepatic bile acid metabolism and insulin action. J Biol Chem 2009; 284:11110-20. [PMID: 19237543 DOI: 10.1074/jbc.m808747200] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The current studies show FGF15 signaling decreases hepatic forkhead transcription factor 1 (FoxO1) activity through phosphatidylinositol (PI) 3-kinase-dependent phosphorylation. The bile acid receptor FXR (farnesoid X receptor) activates expression of fibroblast growth factor (FGF) 15 in the intestine, which acts through hepatic FGFR4 to suppress cholesterol-7alpha hydroxylase (CYP7A1) and limit bile acid production. Because FoxO1 activity and CYP7A1 gene expression are both increased by fasting, we hypothesized CYP7A1 might be a FoxO1 target gene. Consistent with recently reported results, we show CYP7A1 is a direct target of FoxO1. Additionally, we show that the PI 3-kinase pathway is key for both the induction of CYP7A1 by fasting and the suppression by FGF15. FGFR4 is the major hepatic FGF receptor isoform and is responsible for the hepatic effects of FGF15. We also show that expression of FGFR4 in liver was decreased by fasting, increased by insulin, and reduced by streptozotocin-induced diabetes, implicating FGFR4 as a primary target of insulin regulation. Because insulin and FGF both target the PI 3-kinase pathway, these observations suggest FoxO1 is a key node in the convergence of FGF and insulin signaling pathways and functions as a key integrator for the regulation of glucose and bile acid metabolism.
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Selective binding of sterol regulatory element-binding protein isoforms and co-regulatory proteins to promoters for lipid metabolic genes in liver. J Biol Chem 2008; 283:15628-37. [PMID: 18413311 PMCID: PMC2414284 DOI: 10.1074/jbc.m800391200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 04/11/2008] [Indexed: 11/06/2022] Open
Abstract
Mice were subjected to different dietary manipulations to selectively alter expression of hepatic sterol regulatory element-binding protein 1 (SREBP-1) or SREBP-2. mRNA levels for key target genes were measured and compared with the direct binding of SREBP-1 and -2 to the associated promoters using isoform specific antibodies in chromatin immunoprecipitation studies. A diet supplemented with Zetia (ezetimibe) and lovastatin increased and decreased nuclear SREBP-2 and SREBP-1, respectively, whereas a fasting/refeeding protocol dramatically altered SREBP-1 but had modest effects on SREBP-2 levels. Binding of both SREBP-1 and -2 increased on promoters for 3-hydroxy-3-methylglutaryl-CoA reductase, fatty-acid synthase, and squalene synthase in livers of Zetia/lovastatin-treated mice despite the decline in total SREBP-1 protein. In contrast, only SREBP-2 binding was increased for the low density lipoprotein receptor promoter. Decreased SREBP-1 binding during fasting and a dramatic increase upon refeeding indicates that the lipogenic "overshoot" for fatty-acid synthase gene expression known to occur during high carbohydrate refeeding can be attributed to a similar overshoot in SREBP-1 binding. SREBP co-regulatory protein recruitment was also increased/decreased in parallel with associated changes in SREBP binding, and there were clear distinctions for different promoters in response to the dietary manipulations. Taken together, these studies reveal that there are alternative molecular mechanisms for activating SREBP target genes in response to the different dietary challenges of Zetia/lovastatin versus fasting/refeeding. This underscores the mechanistic flexibility that has evolved at the individual gene/promoter level to maintain metabolic homeostasis in response to shifting nutritional states and environmental fluctuations.
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Peroxisome proliferator-activated receptor-gamma coactivator-1alpha activation of CYP7A1 during food restriction and diabetes is still inhibited by small heterodimer partner. J Biol Chem 2008; 283:15089-96. [PMID: 18385139 DOI: 10.1074/jbc.m710452200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cholesterol 7alpha-hydroxylase (CYP7A1) catalyzes the rate-limiting step in the classic pathway of hepatic bile acid biosynthesis from cholesterol. During fasting and in type I diabetes, elevated levels of peroxisome proliferator-activated receptor gamma-coactivator-1alpha (PGC-1alpha) induce expression of the Cyp7A1 gene and overexpression of PGC-1alpha in hepatoma cells stimulates bile acid synthesis. Using Ad-PGC-1alpha-RNA interference to induce acute disruption of PGC-1alpha in mice, here we show that PGC-1alpha is necessary for fasting-mediated induction of CYP7A1. Co-immunoprecipitation and promoter activation studies reveal that the induction of CYP7A1 is mediated by direct interaction between PGC-1alpha and the AF2 domain of liver receptor homolog-1 (LRH-1). In contrast, the very similar PGC-1beta could not substitute for PGC-1alpha. We also show that transactivation of PGC-1alpha and LRH-1 is repressed by the small heterodimer partner (SHP). Treatment of mice with GW4064, a synthetic agonist for farnesoid X receptor, induced SHP expression and decreased both the recruitment of PGC-1alpha to the Cyp7A1 promoter and the fasting-induced expression of CYP7A1 mRNA. These data suggest that PGC-1alpha is an important co-activator for LRH-1 and that SHP targets the interaction between LRH-1 and PGC-1alpha to inhibit CYP7A1 expression. Overall, these studies provide further evidence for the important role of PGC-1alpha in bile acid homeostasis and suggest that pharmacological targeting of farnesoid X receptor in vivo can be used to reverse the increase in CYP7A1 associated with adverse metabolic conditions.
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Two uniquely arranged thyroid hormone response elements in the far upstream 5' flanking region confer direct thyroid hormone regulation to the murine cholesterol 7alpha hydroxylase gene. Nucleic Acids Res 2006; 34:3853-61. [PMID: 16899449 PMCID: PMC1557806 DOI: 10.1093/nar/gkl506] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cholesterol 7α hydroxlyase (CYP7A1) is a key enzyme in cholesterol catabolism to bile acids and its activity is important for maintaining appropriate cholesterol levels. The murine CYP7A1 gene is highly inducible by thyroid hormone in vivo and there is an inverse relationship between thyroid hormone and serum cholesterol. Eventhough gene expression has been shown to be upregulated, whether the induction was mediated through a direct effect of thyroid hormone on the CYP7A1 promoter has never been established. Using gene targeted mice, we show that either of the two TR isoforms are sufficient to maintain normal hepatic CYP7A1 expression but a loss of both results in a significant decrease in expression. We also identified two new functional thyroid hormone receptor-binding sites in the CYP7A1 5′ flanking sequence located 3 kb upstream from the transcription start site. One site is a DR-0, which is an unusual type of TR response element, and the other consists of only a single recognizable half site that is required for TR/retinoid X receptor (RXR) binding. These two independent TR-binding sites are closely spaced and both are required for full induction of the CYP7A1 promoter by thyroid hormone, although the DR-0 site was more crucial.
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A simple promoter containing two Sp1 sites controls the expression of sterol-regulatory-element-binding protein 1a (SREBP-1a). Biochem J 2005; 386:161-8. [PMID: 15462672 PMCID: PMC1134778 DOI: 10.1042/bj20041514] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mammalian gene for SREBP-1 (sterol-regulatory-element-binding protein 1) contains two promoters that control the production of two proteins, SREBP-1a and -1c, and each contains a unique N-terminal transcriptional activation domain, but they are otherwise identical. The relative level of each mRNA varies from tissue to tissue and they respond differently to regulatory stimuli. SREBP-1c is more abundantly expressed in liver, where its level is also regulated by insulin and liver X receptor activators, and it is also autoregulated by SREBPs. In contrast, SREBP-1a mRNA levels are relatively low and constant in different tissues and few studies have specifically analysed its pattern of expression and regulation. In the present study, we show that the promoter for SREBP-1a is contained in a very small promoter-proximal region containing two Sp1 sites. The small and relatively simple structure for its promoter provides an explanation for the low level of SREBP-1a expression. Additionally, since Sp1 has been implicated in the modest regulation of several genes by insulin, its involvement in the expression of the SREBP-1a promoter provides an explanation for the modest insulin regulation observed in animal experiments.
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Abstract
Cholesterol 7-alpha-hydroxylase (CYP7A1) is the key enzyme that commits cholesterol to the neutral bile acid biosynthesis pathway and is highly regulated. In the current studies, we have uncovered a role for the transcriptional co-activator PGC-1alpha in CYP7A1 gene transcription. PGC-1alpha plays a vital role in adaptive thermogenesis in brown adipose tissue and stimulates genes important to mitochondrial function and oxidative metabolism. It is also involved in the activation of hepatic gluconeogenesic gene expression during fasting. Because the mRNA for CYP7A1 was also induced in mouse liver by fasting, we reasoned that PGC-1alpha might be an important co-activator for CYP7A1. Here we show that PGC-1alpha and CYP7A1 are also co-induced in livers of mice in response to streptozotocin induced diabetes. Additionally, infection of cultured HepG2 cells with a recombinant adenovirus expressing PGC-1alpha directly activates CYP7A1 gene expression and increases bile acid biosynthesis as well. Furthermore, we show that PGC-1alpha activates the CYP7A1 promoter directly in transient transfection assays in cultured cells. Thus, PGC-1alpha is a key activator of CYP7A1 and bile acid biosynthesis and is likely responsible for the fasting and diabetes dependent induction of CYP7A1. PGC-1alpha has already been shown to be a critical activator of several other oxidative processes including adaptive thermogenesis and fatty acid oxidation. Our studies provide further evidence of the fundamental role played by PGC-1alpha in oxidative metabolism and define PGC-1alpha as a link between diabetes and bile acid metabolism.
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Thyroid hormone regulation and cholesterol metabolism are connected through Sterol Regulatory Element-Binding Protein-2 (SREBP-2). J Biol Chem 2003; 278:34114-8. [PMID: 12829694 DOI: 10.1074/jbc.m305417200] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
High affinity uptake of serum-derived low density lipoprotein (LDL) cholesterol is accomplished through the LDL receptor in the liver. In mammals, thyroid hormone depletion leads to decreased LDL receptor expression and elevated serum cholesterol. The clinical association in humans has been known since the 1920s; however, a molecular explanation has been lacking. LDL receptor levels are subject to negative feedback regulation by cellular cholesterol through sterol regulatory element-binding protein-2 (SREBP-2). Here we demonstrate that the SREBP-2 gene is regulated by thyroid hormone and that increased SREBP-2 nuclear protein levels in hypothyroid animals results in thyroid hormone-independent activation of LDL receptor gene expression and reversal of the associated hypercholesterolemia. This occurs without effects on other thyroid hormone-regulated genes. Thus, we propose that the decreased LDL receptor and increased serum cholesterol associated with hypothyroidism are secondary to the thyroid hormone effects on SREBP-2. These results suggest that hypercholesterolemia associated with hypothyroidism can be reversed by agents that directly increase SREBP-2. Additionally, these results indicate that mutations or drugs that lower nuclear SREBP-2 would cause hypercholesterolemia.
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Abstract
The cytosolic PEPCK gene is a model gene for assessing retinoid regulation of liver-specific genes encoding enzymes of carbohydrate metabolism. In vivo, we have demonstrated that the PEPCK gene is inhibited by vitamin A deficiency. Specifically, under conditions of food deprivation, induction of the PEPCK gene is inhibited in the vitamin A deficient mouse. Inhibition of the PEPCK gene by vitamin A deficiency is reversed by all-trans or 9-cis retinoic acid (RA) treatment. In a transgenic mouse model, a -460 and -355 bp PEPCK promoter fragment confers susceptibility to inhibition by vitamin A deficiency and responsiveness to all-trans RA treatment. However, there is a differential effect of 9-cis RA on the PEPCK promoter; the -460 fragment confers responsiveness to 9-cis RA, but the -355 fragment does not. Taken together, these results indicate that the PEPCK retinoic acid response element (RARE)1 is required for 9-cis RA induction-but not all-trans RA induction-of the PEPCK gene. In order to determine if vitamin A deficiency alters specific localized expression of the PEPCK gene in the periportal cells of the liver, the effect of vitamin A status on PEPCK localization in the liver was also measured. The PEPCK transgenes were expressed specifically in the periportal region of the liver acinus and although vitamin A deficiency caused a decrease in PEPCK transgene mRNA levels in periportal cells, it did not alter the periportal cell-specific pattern of expression. Retinoid treatment induced PEPCK transgene mRNA levels in the same population of cells, however, the -355 bp PEPCK promoter fragment did not respond to 9-cis RA treatment. In order to determine the nuclear transcription factor(s) responsible for retinoid regulation of the PEPCK gene in the liver, we investigated retinoic acid receptor (RAR)alpha and beta and the retinoid X receptor (RXR)alpha-the major retinoid receptors in liver-in terms of expression and the ability of the receptors to bind the PEPCK RAREs. Vitamin A deficiency significantly decreased hepatic RAR beta, but not RAR alpha or RXR alpha mRNA levels. In situ hybridization showed that RAR alpha, RAR beta and RXR alpha mRNAs were localized in the periportal region, however, immunohistochemistry showed that RAR alpha and RXR alpha were distributed evenly across the liver acinus, whereas only RAR beta levels were higher in periportal cells. The binding of nuclear receptors to PEPCK RARE1, RARE2 and RARE3 indicates a complex pattern of retinoid receptor and orphan nuclear receptor binding.
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Abstract
Allele frequency and forensic parameters for eleven STR loci were surveyed in a random sample from the Korean population.
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Abstract
We have developed four multiplex genotyping systems (GeneKin Y-STR multiplexes) using silver staining with allelic ladders for ten Y-chromosome STR markers (DYS19, DYS385, DYS388, DYS389I/II, DYS390, DYS391, DYS392, DYS393 and DXYS156Y), with a view towards the application of rapid and simple genotyping assay methods for DNA profiling. The GeneKin Y-STR multiplexes developed have followed the published nomenclature and ISFG guidelines for STR analysis. Allele and haplotype frequencies at these Y-STRs loci were analysed by PCR amplification using the GeneKin Y-STR multiplexes, followed by denaturing polyacrylamide gel electrophoresis in 316 unrelated males in the Korean population. A total of 295 different haplotypes were found, 279 of them being unique. Gene diversity ranged from 0.4026 at DYS391 to 0.9606 at DYS385. The haplotype diversity value (which is the same as the discrimination index) calculated from all ten loci combined was 0.9995, which is informative. Our results revealed that a set of ten Y-STRs can discriminate between most of the male individuals in the Korean population (discrimination capacity: 93.35%). The Y-STR multiplexes thus provide useful information for forensic analysis and paternity tests and can also be of great benefit for providing information not normally available from autosomal DNA systems.
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Diffraction by a subwavelength-sized aperture in a metal plane. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2001; 18:1477-1486. [PMID: 11444539 DOI: 10.1364/josaa.18.001477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present an experimental study on the diffraction of light by an aperture small compared with the wavelength. The aperture is illuminated by laser light guided in a metal-clad tapered optical fiber. We investigate different orientations of the aperture in the plane: normal to the cleaved plane, oblique to the cleaved plane, and off-center. We measure the far-field, two-dimensional intensity distributions of the diffracted light as functions of angle coordinates theta and phi in a full half-space for various polarization states and analyze the patterns by using low-order multipole fields. We also examine the near- and far-field effects of placing small periodic corrugations near the aperture, focusing on the role of surface-wave excitations. We measure the near-field intensity distributions near the aperture with a near-field scanning optical microscope and discuss their relation to the far-field diffracted fields.
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Abstract
Allele and haplotype frequencies of seven Y-chromosome STR loci were determined from a sample of 330 unrelated males in the Korean population.
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Y chromosomal DNA variation in east Asian populations and its potential for inferring the peopling of Korea. J Hum Genet 2000; 45:76-83. [PMID: 10721667 DOI: 10.1007/s100380050015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have examined variations of five polymorphic loci (DYS287, DXYS5Y, SRY465, DYS19, and DXYS156Y) on the Y chromosome in samples from a total of 1260 males in eight ethnic groups of East Asia. We found four unique haplotypes constructed from three biallelic markers in these samples of East Asians. The Japanese population was characterized by a relatively high frequency of either the haplotype I-2b (-/Y2/T) or II-1 (+/Y1/C). These dual patterns of the distribution of Y chromosomes (I-2b/II-1) were also found in Korea, although they were present at relatively low frequencies. The haplotype II-1 was present in Northeast Asian populations (Chinese, Japanese, Koreans, and Mongolians) only, except for one male from the Thai population among the Southeast Asian populations (Indonesians, Philippines, Thais, and Vietnamese). The Japanese were revealed to have the highest frequency of this haplotype (27.5%), followed by Koreans (2.9%), Mongolians (2.6%), and mainland Chinese (2.2%). In contrast, the frequency of the haplotype I-2b was found to be 17.1% in the Japanese, 9.5% in Indonesian, 6.3% in Korean, 3.8% in Vietnamese, and 2.7% in Thai samples. These findings suggested that the chromosomes of haplotype I-2b were likely derived from certain areas of Northeast Asia, the region closest to Southeast Asia. Phylogenetic analysis using the neighbor-joining tree also reflected a general distinction between Southeast and Northeast Asian populations. The phylogeny revealed a closer genetic relationship between Japanese and Koreans than to the other surveyed Asian populations. Based on the result of the dual patterns of the haplotype distribution, it is more likely that the population structure of Koreans may not have evolved from a single ancient population derived from Northeast Asians, but through dual infusions of Y chromosomes entering Korea from two different waves of East Asians.
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Multipole analysis of the radiation from near-field optical probes. OPTICS LETTERS 2000; 25:171-173. [PMID: 18059819 DOI: 10.1364/ol.25.000171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We experimentally and theoretically analyze the radiation emitted from subwavelength-sized apertures in near-field optical probes. By decomposing the experimentally obtained radiation patterns into vector spherical waves, we describe the fields in terms of a series of multipole sources. We fit polarization-resolved angular intensity distributions, measured as far as 150 degrees from the normal, with dipole, quadrupole, and octupole radiation. We find that the magnetic and the electric dipole components are dominant but that the interference terms between dipoles and higher-order poles are not negligible. This result can be used as the basis for understanding near-field optical interactions and images.
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Abstract
Diffracted fields from 100-nm aperture near-field scanning optical microscopy (NSOM) probes and uncoated tapered fibres are measured and analysed. Using a solid angle scanner, the two-dimensional intensity distribution and polarization state of the diffracted light are resolved experimentally. Polarization analyses show that circularly polarized input light does not maintain its polarization state for all diffraction angles, and is completely filtered into linearly polarized light at large polar diffraction angles. This drastic decomposition originates from the vector nature of light diffracted by the sub-wavelength aperture. There is a fundamental difficulty in generating circularly polarized light near the aperture of NSOM probes owing to polarization-dependent diffraction in the near-field regime. This is illustrated by the Bethe-Bouwkamp model using circularly polarized input light.
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Abstract
The Y Alu polymorphic (YAP) element (DYS287) and the Y-linked tetranucleotide microsatellite locus DYS19 were examined in samples from a total of 455 unrelated males in the Korean population. The frequency of the YAP allele was found to be 1.3% (6/455) in the Korean population. These results are consistent with previous reports that showed the YAP element to be absent in most Asian populations, with the exception of the high frequency of the YAP allele in the Japanese population. All five common alleles at the DYS19 locus were identified in this study, The C allele was the most frequent (197/455), followed by the D (119/455), B (78/455), E (41/455), and A (20/455) alleles. Seven combination haplotypes (DYS287/DYS19) were found, and the mean combination haplotype diversity in the Korean population appeared to be 0.71. Based on results of these two loci, Japanese and Korean populations may share some common genetic structure that could reflect recent gene flow and some amount of admixture of Y chromosomes between these two populations.
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Noncollimated bidirectional shearing interferometer for measuring a long radius of curvature. APPLIED OPTICS 1997; 36:5317-5320. [PMID: 18259348 DOI: 10.1364/ao.36.005317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A method for measuring a long radius of curvature with a modified half-aperture bidirectional shearing interferometer is described. A plane mirror of the interferometer is replaced with a test mirror, and the incident beam is decollimated by shifting of the source to equalize the widths of the bidirectional shearing fringes reflected from the plane and test mirrors. This method can be applied to concave and convex surfaces.
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Vitamin A regulates genes involved in hepatic gluconeogenesis in mice: phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. J Nutr 1997; 127:1274-8. [PMID: 9202079 DOI: 10.1093/jn/127.7.1274] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We examined the effects of vitamin A deficiency and all-trans retinoic acid (RA) supplementation on regulation of three important genes in hepatic gluconeogenesis: the genes for phosphoenolpyruvate carboxykinase (PEPCK), fructose-1,6-bisphosphatase (Fru-1,6-P2ase) and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (6-PF-2-K/Fru-2,6-P2ase). Mice were made vitamin A deficient in the second generation by initiating a vitamin A-deficient diet on d 10 of gestation. At 7 wk of age, vitamin A-deficient mice were treated with all-trans RA or vehicle alone and killed for RNA analysis. In liver, vitamin A deficiency resulted in PEPCK mRNA levels that were 74% lower and 6-PF-2-K/Fru-2,6-P2ase mRNA levels that were 42% lower than the respective mRNA measured in control mice. The Fru-1,6-P2ase mRNA abundance was not affected by vitamin A deficiency. The decrease in hepatic PEPCK and 6-PF-2-K/Fru-2,6-P2ase mRNA levels was reversed by treatment with all-trans RA within 3 h of administration. In mice fed the control diet, food deprivation for 15 h resulted in PEPCK mRNA levels that were 3.5-fold higher, Fru-1,6-P2ase mRNA levels that were 2-fold higher, and 6-PF-2-K/Fru-2,6-P2ase mRNA levels that were 3.4-fold higher than in fed mice. Vitamin A-deficient mice did not respond to food deprivation with induced PEPCK mRNA levels, whereas 6-PF-2-K/Fru-2,6-P2ase and Fru-1,6-P2ase mRNA levels were induced. The pattern of 6-PF-2-K/Fru-2,6-P2ase mRNA abundance with vitamin A deficiency and food deprivation was complex and different from that for either PEPCK or Fru-1,6-P2ase transcripts. The cAMP-responsiveness of the PEPCK gene in vitamin A-deficient mice was tested. Vitamin A deficiency caused a significant reduction in cAMP stimulation of PEPCK mRNA levels in liver. These results in the whole animal indicate that vitamin A regulation of the hepatic PEPCK gene is physiologically important; without adequate vitamin A nutriture, stimulation of the PEPCK gene by food deprivation or cAMP treatment is inhibited in the liver.
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Abstract
We prospectively examined 45 patients with serial echocardiography to measure left ventricular end-diastolic volume index within 1 week and at 6 weeks after infarction. Left ventricular volume increased in patients with Q-wave infarction but not in those with non-Q or in control patients without recent infarction. Peak creatine phosphokinase levels were greater in Q-wave infarction compared with those in non-Q-wave infarction. There was a strong correlation between the change in the left ventricular end-diastolic index and the peak creatine phosphokinase level. After correcting for infarct size, there was still a difference between the two groups. Our data indicate that ventricular remodeling does not occur in non-Q-wave as opposed to Q-wave infarcts, and this may be related both to the limited amount of myocardial necrosis and to the nontransmural extent of the necrosis.
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Effects of vitamin A deficiency and retinoic acid treatment on expression of a phosphoenolpyruvate carboxykinase-bovine growth hormone gene in transgenic mice. Biochem Biophys Res Commun 1995; 213:706-14. [PMID: 7646527 DOI: 10.1006/bbrc.1995.2188] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Vitamin A regulation of specific promoter domains of the phosphoenolpyruvate carboxykinase (PEPCK) gene was tested in a PEPCK/bovine growth hormone (bGH) transgenic mouse model. Vitamin A deficiency causes a significant decrease in hepatic bGH mRNA when expression is driven by either a 533-base-pair (bp) PEPCK promoter fragment (from position -460 to +73) or a 428-bp PEPCK promoter fragment (from position -355 to +73). Treatment of vitamin A deficient transgenic mice with all-trans retinoic acid (RA) increases bGH mRNA levels above those measured with the deficiency. Hepatic retinoic acid receptor (RAR)beta mRNA levels also change with vitamin A deficiency and supplementation, but not RAR alpha mRNA levels. These results indicate that all-trans RA plays a physiologic role in regulating expression of a gluconeogenic gene in liver.
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Abstract
It has been known that the vestibular system is concerned with feelings of dizziness or vertigo. The vestibulo-thalamic pathway has also been described previously. However, there has been no confirmative report so far regarding the pathway through the internal capsule to the cortex. We have experienced 13 patients with symptoms of dizziness and/or vertigo whose lesions are located only around the internal capsule, mainly at the posterior limb and/or the genu. It is suggestive that fibers with dizziness may pass through a part of the internal capsule, probably through some part of the posterior limb and/or the genu.
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