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1.
Hepatol Commun ; 1(4): 311-325, 2017 06.
Article in English | MEDLINE | ID: mdl-29404461

ABSTRACT

CAT-2003 is a novel conjugate of eicosapentaenoic acid (EPA) and niacin designed to be hydrolyzed by fatty acid amide hydrolase to release EPA inside cells at the endoplasmic reticulum. In cultured liver cells, CAT-2003 blocked the maturation of sterol regulatory element-binding protein (SREBP)-1 and SREBP-2 proteins and decreased the expression of multiple SREBP target genes, including HMGCR and PCSK9. Consistent with proprotein convertase subtilisin/kexin type 9 (PCSK9) reduction, both low-density lipoprotein receptor protein at the cell surface and low-density lipoprotein particle uptake were increased. In apolipoprotein E*3-Leiden mice fed a cholesterol-containing western diet, CAT-2003 decreased hepatic inflammation and steatosis as evidenced by fewer inflammatory cell aggregates in histopathologic sections, decreased nuclear factor kappa B activity in liver lysates, reduced inflammatory gene expression, reduced intrahepatic cholesteryl ester and triglyceride levels, and decreased liver mass. Plasma PCSK9 was reduced and hepatic low-density lipoprotein receptor protein expression was increased; plasma cholesterol and triglyceride levels were lowered. Aortic root segments showed reduction of several atherosclerotic markers, including lesion size, number, and severity. CAT-2003, when dosed in combination with atorvastatin, further lowered plasma cholesterol levels and decreased hepatic expression of SREBP target genes. Conclusion: SREBP inhibition is a promising new strategy for the prevention and treatment of diseases associated with abnormal lipid metabolism, such as atherosclerosis and nonalcoholic steatohepatitis. (Hepatology Communications 2017;1:311-325).

2.
J Med Chem ; 59(3): 1217-31, 2016 Feb 11.
Article in English | MEDLINE | ID: mdl-26784936

ABSTRACT

This report describes the synthesis and preliminary biological characterization of novel fatty acid niacin conjugates and fatty acid salicylate conjugates. These molecular entities were created by covalently linking two bioactive molecules, either niacin or salicylic acid, to an omega-3 fatty acid. This methodology allows the simultaneous intracellular delivery of two bioactives in order to elicit a pharmacological response that could not be replicated by administering the bioactives individually or in combination. The fatty acid niacin conjugate 5 has been shown to be an inhibitor of the sterol regulatory element binding protein (SREBP), a key regulator of cholesterol metabolism proteins such as PCSK9, HMG-CoA reductase, ATP citrate lyase, and NPC1L1. On the other hand, the fatty acid salicylate conjugate 11 has been shown to have a unique anti-inflammatory profile based on its ability to modulate the NF-κB pathway through the intracellular release of the two bioactives.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemistry , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Fatty Acids/chemistry , Niacin/chemistry , Niacin/pharmacology , Salicylic Acid/chemistry , Salicylic Acid/pharmacology , Administration, Oral , Animals , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Cell Line , Dogs , Dose-Response Relationship, Drug , Hep G2 Cells , Humans , Hydrolysis , Liver/drug effects , Liver/metabolism , Mice , Molecular Structure , NF-kappa B/antagonists & inhibitors , NF-kappa B/metabolism , Niacin/administration & dosage , Rats , Rats, Sprague-Dawley , Salicylic Acid/administration & dosage , Sterol Regulatory Element Binding Protein 1/antagonists & inhibitors , Sterol Regulatory Element Binding Protein 1/metabolism , Sterol Regulatory Element Binding Protein 2/antagonists & inhibitors , Sterol Regulatory Element Binding Protein 2/metabolism , Structure-Activity Relationship , Tissue Distribution
3.
BMC Med Res Methodol ; 12: 31, 2012 Mar 19.
Article in English | MEDLINE | ID: mdl-22429514

ABSTRACT

BACKGROUND: Sample sizes for obstetrical trials are often based on the opinion of investigators about clinically important effect size. We surveyed Canadian obstetricians to investigate clinically important effect sizes required before introducing new treatments into practice to prevent preterm birth. METHODS: Questionnaires were mailed to practicing obstetricians, asking the magnitude of pregnancy prolongation required to introduce treatments into practice. The three prophylactic treatments were of increasing invasiveness: vaginal progesterone, intramuscular progesterone, and cervical cerclage. We also asked about the perceived most relevant outcome measures for obstetrical trials and current obstetrical practice in preterm birth prevention. RESULTS: 544/1293(42.1%) completed questionnaires were received. The majority of respondents required one or two weeks' increase in length of gestation before introducing vaginal (372,77.1%), and intramuscular progesterone(354,67.9%). At least three weeks increase was required before introducing prophylactic cervical cerclage(326,62.8%). Clinicians who already used a treatment required a smaller difference before introducing it into practice. Decreasing neonatal morbidity was cited as the most important outcome for obstetrical trials (349,72.2%). CONCLUSION: Obstetricians would require a larger increase in treatment effect before introducing more invasive treatments into practice. Although infant morbidity was perceived as a more important outcome, clinicians appeared willing to change practice on the basis of prolongation of pregnancy, a surrogate outcome. We found that there is not a single minimum clinically important treatment effect that will influence all practising clinicians: rather the effect size that will influence physicians is affected by the nature of the treatment, the reported outcome measure and the clinician's own current clinical practice.


Subject(s)
Obstetrics/standards , Physicians/psychology , Practice Patterns, Physicians' , Premature Birth/prevention & control , Administration, Intravaginal , Canada , Cerclage, Cervical/methods , Clinical Trials as Topic , Decision Making , Evidence-Based Medicine , Female , Humans , Injections, Intramuscular , Physicians/statistics & numerical data , Pregnancy , Pregnancy Outcome , Pregnancy, Multiple , Pregnancy, Prolonged/prevention & control , Premature Birth/drug therapy , Progesterone/administration & dosage , Progesterone/therapeutic use , Randomized Controlled Trials as Topic/methods , Randomized Controlled Trials as Topic/statistics & numerical data , Research Design , Sample Size , Surveys and Questionnaires
4.
Neurourol Urodyn ; 30(3): 390-4, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21284021

ABSTRACT

OBJECTIVE: To estimate the incidence of stress urinary incontinence (SUI) following vaginal repair of pelvic organ prolapse (POP) in preoperatively continent women and to evaluate the impact of the problem. METHODS: Women were eligible if they had undergone vaginal repairs for any degree or type of POP with no anti-incontinence procedure between July 1, 2004 and June 30, 2006, and had been continent preoperatively, as defined by a negative cough stress test with or without reduction of prolapse. Demographic, preoperative, operative, and postoperative data were retrieved from hospital charts. The incidence of postoperative SUI (POSUI) and its quality of life (QoL) impact were assessed by mailed questionnaire. The POSUI endpoint was defined by the report of SUI symptoms on the mailed questionnaire and/or affirmation of postoperative treatment for SUI. RESULTS: Forty-two out of 100 respondents reported POSUI within the 2-year average follow-up period. Twelve of 37 symptomatic women (32%) were moderately or greatly bothered by their symptoms. The QoL impact score was generally low but was statistically greater in women with POSUI compared to those with no POSUI (13 vs. 3, P=0.0006). CONCLUSION: The risk of POSUI following vaginal repairs of POP may be higher than previously reported and approximately one-third of women are bothered by these symptoms. These findings deserve further investigation.


Subject(s)
Pelvic Organ Prolapse/surgery , Urinary Incontinence, Stress/epidemiology , Urologic Surgical Procedures/adverse effects , Adult , Aged , Aged, 80 and over , Alberta , Female , Humans , Incidence , Middle Aged , Pelvic Organ Prolapse/physiopathology , Pelvic Organ Prolapse/psychology , Quality of Life , Retrospective Studies , Risk Assessment , Risk Factors , Surveys and Questionnaires , Time Factors , Treatment Outcome , Urinary Bladder/physiopathology , Urinary Incontinence, Stress/etiology , Urinary Incontinence, Stress/physiopathology , Urinary Incontinence, Stress/psychology
5.
Neurourol Urodyn ; 30(4): 572-7, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21268100

ABSTRACT

AIMS: Urodynamic studies (UDS) are complex, invasive and may be emotionally and physically distressing. Inadequate information may heighten distress. Prior to UDS, our patients receive written and verbal information, yet concerns remains that some women may not be adequately informed. This study examined how informed women believe they are to undergo UDS in our clinic. METHODS: This was a before-after questionnaire-based study. Data were collected from a convenience sample of 200 women prior to UD testing, and within 3 days of completion. Participants rated their level of agreement/disagreement with the following statements: I understand why I am having the test; I have been given enough information about the test; I understand what the test will involve. Women also reported their perceived levels of distress (anxiety, embarrassment, and discomfort). RESULTS: One hundred fifty-one women returned both pre- and post-UD questionnaires. Most (88.9%) had read the information sheet and agreed that they understood the indications for the testing (78.1%). Fewer agreed that they understood what the tests would involve (68.2%), or that they had been given enough information about the test (64.9%). The overall distress score (anxiety, embarrassment, and discomfort) was 6 (IQR 5-7; possible range 3-9). CONCLUSIONS: Urodynamic testing remains an invasive yet prevalent form of urogynecological assessment. One-third of our patients may not understand what UD testing involves and may not feel adequately informed about the tests. Additional research to explore informational needs is important.


Subject(s)
Health Knowledge, Attitudes, Practice , Patient Education as Topic , Urinary Incontinence, Stress/diagnosis , Urodynamics , Anxiety/psychology , Female , Humans , Surveys and Questionnaires , Urinary Incontinence, Stress/psychology , Women
6.
Female Pelvic Med Reconstr Surg ; 17(4): 174-9, 2011 Jul.
Article in English | MEDLINE | ID: mdl-22453847

ABSTRACT

OBJECTIVE: : This study aimed to determine the midterm efficacy of porcine small intestine submucosa for paravaginal repairs of anterior vaginal prolapse. METHODS: : One hundred five women underwent repairs between 2003 and 2006 and met our inclusion criteria. Women were invited to return for a pelvic examination and to fill out validated questionnaires. Objective failure was defined as anterior prolapse recurrence at or beyond the hymen. RESULTS: : Fifty-nine women (56%) were available for follow-up. Median age of patients was 60 years (range, 26-80 years) and 83% had a parity of 2 or more. Ninety-seven percent of patients had a preoperative prolapse stage of 2 or more. Follow-up ranged from 1 to 5 years (median, 27.5 months; interquartile range, 14.5). The most common postoperative complication was transient voiding dysfunction (23.7%). Objective cure rate was 68.8%. A positive change in bladder, vaginal, and bowel symptoms (a little better, much better, or very much better) was reported by 69.5%, 59.3%, and 25.5% of women, respectively. Thirty-one women (52.5%) were sexually active at postoperative follow-up. Only 4 women (6.8%) were not sexually active because of pelvic symptoms. Dyspareunia was reported by 8.3% of the 48 women who returned for a clinic follow-up. Twenty-four women (40.7%) were not sexually active postoperatively, for reasons unrelated to their surgeries. CONCLUSIONS: : Vaginal paravaginal repair using porcine xenograft is a safe procedure whose long-term efficacy needs further evaluation through prospective trials.

7.
Am J Physiol Endocrinol Metab ; 298(3): E419-28, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19996381

ABSTRACT

Chronic inflammation is an important etiology underlying obesity-related disorders such as insulin resistance and type 2 diabetes, and recent findings indicate that the macrophage can be the initiating cell type responsible for this chronic inflammatory state. The mammalian silent information regulator 2 homolog SIRT1 modulates several physiological processes important for life span, and a potential role of SIRT1 in the regulation of insulin sensitivity has been shown. However, with respect to inflammation, the role of SIRT1 in regulating the proinflammatory pathway within macrophages is poorly understood. Here, we show that knockdown of SIRT1 in the mouse macrophage RAW264.7 cell line and in intraperitoneal macrophages broadly activates the JNK and IKK inflammatory pathways and increases LPS-stimulated TNFalpha secretion. Moreover, gene expression profiles reveal that SIRT1 knockdown leads to an increase in inflammatory gene expression. We also demonstrate that SIRT1 activators inhibit LPS-stimulated inflammatory pathways, as well as secretion of TNFalpha, in a SIRT1-dependent manner in RAW264.7 cells and in primary intraperitoneal macrophages. Treatment of Zucker fatty rats with a SIRT1 activator leads to greatly improved glucose tolerance, reduced hyperinsulinemia, and enhanced systemic insulin sensitivity during glucose clamp studies. These in vivo insulin-sensitizing effects were accompanied by a reduction in tissue inflammation markers and a decrease in the adipose tissue macrophage proinflammatory state, fully consistent with the in vitro effects of SIRT1 in macrophages. In conclusion, these results define a novel role for SIRT1 as an important regulator of macrophage inflammatory responses in the context of insulin resistance and raise the possibility that targeting of SIRT1 might be a useful strategy for treating the inflammatory component of metabolic diseases.


Subject(s)
Inflammation/metabolism , Insulin Resistance/genetics , Insulin/metabolism , Macrophage Activation/genetics , Macrophages/metabolism , Sirtuin 1/metabolism , Animals , Cells, Cultured , Gene Expression , Male , Mice , Rats , Rats, Zucker , Signal Transduction
8.
BMC Pregnancy Childbirth ; 9: 50, 2009 Oct 30.
Article in English | MEDLINE | ID: mdl-19874628

ABSTRACT

BACKGROUND: The rate of caesarean sections is increasing worldwide, yet medical literature informing women with uncomplicated pregnancies about relative risks and benefits of elective caesarean section (CS) compared with vaginal delivery (VD) remains scarce. A decision board may address this gap, providing systematic evidence-based information so that patients can more fully understand their treatment options. The objective of our study was to design and pre-test a decision board to guide clinical discussions and enhance informed decision-making related to delivery approach (CS or VD) in uncomplicated pregnancy. METHODS: Development of the decision board involved two preliminary studies to determine women's preferred mode of risk presentation and a systematic literature review for the most comprehensive presentation of medical risks at the time (VD and CS). Forty women were recruited to pre-test the tool. Eligible subjects were of childbearing age (18-40 years) but were not pregnant in order to avoid raising the expectation among pregnant women that CS was a universally available birth option. Women selected their preferred delivery approach and completed the Decisional Conflict Scale to measure decisional uncertainty before and after reviewing the decision board. They also answered open-ended questions reflecting what they had learned, whether or not the information had helped them to choose between birth methods, and additional information that should be included. Descriptive statistics were used to analyse sample characteristics and women's choice of delivery approach pre/post decision board. Change in decisional conflict was measured using Wilcoxon's sign rank test for each of the three subscales. RESULTS: The majority of women reported that they had learned something new (n = 37, 92%) and that the tool had helped them make a hypothetical choice between delivery approaches (n = 34, 85%). Women wanted more information about neonatal risks and personal experiences. Decisional uncertainty decreased (p < 0.001) and perceived effectiveness of decisions increased (p < 0.001) post-intervention. CONCLUSION: Non-pregnant women of childbearing age were positive about the decision board and stated their hypothetical delivery choices were informed by risk presentation, but wanted additional information about benefits and experiences. This study represents a preliminary but integral step towards ensuring women considering delivery approaches in uncomplicated pregnancies are fully informed.


Subject(s)
Cesarean Section , Choice Behavior , Decision Support Techniques , Informed Consent , Patient Preference , Pregnancy/psychology , Adolescent , Adult , Female , Humans , Patient Education as Topic , Patient Participation , Young Adult
9.
Health Expect ; 12(3): 288-300, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19754692

ABSTRACT

OBJECTIVES: To explore women's goals and goal attainment for the conservative and surgical treatment of stress urinary incontinence (SUI), and to examine the feasibility of Goal Attainment Scaling (GAS) as an outcome measure in this population. BACKGROUND: Despite the range of treatments for SUI, little is known about the outcomes patients consider important. Current instruments measure the impact of SUI on the ability to live a 'normal' life without addressing what normal looks like for the patient. Patient-generated measures that address what a patient aims to achieve may fill this gap. DESIGN: A mixed-methods exploratory design combined semi-structured interviews with validated questionnaires and individualized rating of goal achievement. SETTING AND PARTICIPANTS PARTICIPANTS: with SUI (n = 18) were interviewed in their homes prior to initiation of treatment and 3-6 months afterwards. MAIN VARIABLES: Participants reported individualized goals pre-treatment and rated goal attainment after surgical and conservative therapy. Quality of life impact and change were measured using short forms of the Incontinence Impact Questionnaire and Urinary Distress Inventory. RESULTS: Women expressed a median of four highly individualized treatment-related goals but goal achievement following conservative treatment was poor. GAS was not feasible as an outcome measure; women readily identified personal goals but could not independently identify graded levels of attainment for each goal. CONCLUSIONS: Although further work is needed to examine the most feasible, valid, and reliable method of measuring goal achievement in research, asking patients with UI to identify pre-treatment goals may provide useful information to guide treatment-related decision making.


Subject(s)
Goals , Urinary Incontinence, Stress/prevention & control , Urinary Incontinence, Stress/psychology , Achievement , Feasibility Studies , Female , Humans , Interviews as Topic , Middle Aged , Patient-Centered Care , Pilot Projects , Quality of Life , Statistics, Nonparametric , Surveys and Questionnaires
10.
Int Urogynecol J Pelvic Floor Dysfunct ; 20(10): 1243-52, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19517050

ABSTRACT

INTRODUCTION AND HYPOTHESIS: This study investigated changes in participant knowledge, symptoms, and condition-specific quality of life after a 2.5-h nurse-ran workshop on pelvic floor health. METHODS: Data were collected prospectively on a convenience cohort of 51 women who completed questionnaires before, immediately after, and 3 months after the workshop. RESULTS: Participant response rate for questionnaire completion at 3 months was 83%. The median preworkshop knowledge score was 28/39 and median scores immediately postworkshop and at 3 months were 36/39 and 33/39. Knowledge scores were significantly higher immediately postworkshop (p < 0.01) and 3 months post (p < 0.01) when compared with knowledge scores preworkshop. Symptom and quality-of-life scores significantly improved from baseline to 3 months (Pelvic Floor Impact Questionnaire: mean difference = 14.2, p = 0.005, 95% confidence interval (CI) 4.7-23.8; Pelvic Floor Distress Inventory: mean difference = 17.4, p < 0.001, 95% CI 8.3-26.5). CONCLUSION: Women's knowledge, symptoms, and quality-of-life scores significantly improved at 3 months compared to baseline preworkshop scores.


Subject(s)
Health Knowledge, Attitudes, Practice , Patient Education as Topic , Pelvic Organ Prolapse , Quality of Life , Urinary Incontinence , Aged , Female , Humans , Learning , Middle Aged , Outcome Assessment, Health Care , Surveys and Questionnaires
11.
J Biol Chem ; 284(36): 24394-405, 2009 Sep 04.
Article in English | MEDLINE | ID: mdl-19535340

ABSTRACT

SIRT3 is a major mitochondrial NAD(+)-dependent protein deacetylase playing important roles in regulating mitochondrial metabolism and energy production and has been linked to the beneficial effects of exercise and caloric restriction. SIRT3 is emerging as a potential therapeutic target to treat metabolic and neurological diseases. We report the first sets of crystal structures of human SIRT3, an apo-structure with no substrate, a structure with a peptide containing acetyl lysine of its natural substrate acetyl-CoA synthetase 2, a reaction intermediate structure trapped by a thioacetyl peptide, and a structure with the dethioacetylated peptide bound. These structures provide insights into the conformational changes induced by the two substrates required for the reaction, the acetylated substrate peptide and NAD(+). In addition, the binding study by isothermal titration calorimetry suggests that the acetylated peptide is the first substrate to bind to SIRT3, before NAD(+). These structures and biophysical studies provide key insight into the structural and functional relationship of the SIRT3 deacetylation activity.


Subject(s)
Acetate-CoA Ligase/chemistry , Mitochondrial Proteins/chemistry , NAD/chemistry , Peptides/chemistry , Sirtuins/chemistry , Acetate-CoA Ligase/metabolism , Acetylation , Humans , Mitochondria/enzymology , Mitochondrial Proteins/metabolism , Peptides/metabolism , Protein Binding/physiology , Protein Structure, Quaternary , Sirtuin 3 , Sirtuins/metabolism , Structure-Activity Relationship
12.
FASEB J ; 23(9): 2810-9, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19376817

ABSTRACT

Inappropriate elevation of matrix metalloproteinase-9 (MMP9) is reported to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). The object of this study was to identify the molecular mechanism underlying this increase of MMP9 expression, and here we show that oxidative stress-dependent reduction of a protein deacetylase, SIRT1, known as a putative antiaging enzyme, causes elevation of MMP9 expression. A sirtuin inhibitor, splitomycin, and SIRT1 knockdown by RNA interference led an increase in MMP9 expression in human monocytic U937 cells and in primary sputum macrophages, which was detected by RT-PCR, Western blot, activity assay, and zymography. In fact, the SIRT1 level was significantly decreased in peripheral lungs of patients with COPD, and this increase was inversely correlated with MMP9 expression and MMP9 promoter activation detected by a chromatin immunoprecipitation assay. H(2)O(2) reduced SIRT1 expression and activity in U937 cells; furthermore, cigarette smoke exposure also caused reduction of SIRT1 expression in lung tissue of A/J mice, with concomitant elevation of MMP9. Intranasal treatment of a selective and novel SIRT1 small molecule activator, SRT2172, blocked the increase of MMP9 expression in the lung as well as pulmonary neutrophilia and the reduction in exercise tolerance. Thus, SIRT1 is a negative regulator of MMP9 expression, and SIRT1 activation is implicated as a novel therapeutic approach to treating chronic inflammatory diseases, in which MMP9 is abundant.


Subject(s)
Matrix Metalloproteinase 9/metabolism , Sirtuins/physiology , Animals , Cell Line , Gene Expression Regulation , Humans , Hydrogen Peroxide , Inflammation , Lung/pathology , Macrophages , Matrix Metalloproteinase 9/analysis , Matrix Metalloproteinase 9/genetics , Mice , Monocytes , Oxidative Stress , Promoter Regions, Genetic , Pulmonary Disease, Chronic Obstructive/metabolism , Pulmonary Disease, Chronic Obstructive/pathology , Sirtuin 1 , Sirtuins/analysis , Sirtuins/genetics , Smoke/adverse effects , Nicotiana
13.
Nature ; 458(7241): 1056-60, 2009 Apr 23.
Article in English | MEDLINE | ID: mdl-19262508

ABSTRACT

AMP-activated protein kinase (AMPK) is a metabolic fuel gauge conserved along the evolutionary scale in eukaryotes that senses changes in the intracellular AMP/ATP ratio. Recent evidence indicated an important role for AMPK in the therapeutic benefits of metformin, thiazolidinediones and exercise, which form the cornerstones of the clinical management of type 2 diabetes and associated metabolic disorders. In general, activation of AMPK acts to maintain cellular energy stores, switching on catabolic pathways that produce ATP, mostly by enhancing oxidative metabolism and mitochondrial biogenesis, while switching off anabolic pathways that consume ATP. This regulation can take place acutely, through the regulation of fast post-translational events, but also by transcriptionally reprogramming the cell to meet energetic needs. Here we demonstrate that AMPK controls the expression of genes involved in energy metabolism in mouse skeletal muscle by acting in coordination with another metabolic sensor, the NAD+-dependent type III deacetylase SIRT1. AMPK enhances SIRT1 activity by increasing cellular NAD+ levels, resulting in the deacetylation and modulation of the activity of downstream SIRT1 targets that include the peroxisome proliferator-activated receptor-gamma coactivator 1alpha and the forkhead box O1 (FOXO1) and O3 (FOXO3a) transcription factors. The AMPK-induced SIRT1-mediated deacetylation of these targets explains many of the convergent biological effects of AMPK and SIRT1 on energy metabolism.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Energy Metabolism , NAD/metabolism , Sirtuins/metabolism , Acetylation , Aminoimidazole Carboxamide/analogs & derivatives , Animals , Cell Line , Energy Metabolism/genetics , Enzyme Activation , Forkhead Box Protein O1 , Forkhead Box Protein O3 , Forkhead Transcription Factors/genetics , Gene Expression Regulation , Genes, Mitochondrial/genetics , Male , Mice , Muscle, Skeletal/cytology , Muscle, Skeletal/enzymology , Muscle, Skeletal/metabolism , Mutation , Oxygen Consumption , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , Phosphorylation , Ribonucleotides , Sirtuin 1 , Trans-Activators/genetics , Trans-Activators/metabolism , Transcription Factors , Transcription, Genetic
14.
Bioorg Med Chem Lett ; 19(8): 2350-3, 2009 Apr 15.
Article in English | MEDLINE | ID: mdl-19303289

ABSTRACT

SIRT1 is an NAD(+)-dependent protein deacetylase that appears to produce beneficial effects on metabolic parameters such as glucose and insulin homeostasis. Activation of SIRT1 by resveratrol (1) has been shown to modulate insulin resistance, increase mitochondrial content and prolong survival in lower organisms and in mice on a high fat diet. Herein, we describe the identification and SAR of a series of oxazolo[4,5-b]pyridines as novel small molecule activators of SIRT1 which are structurally unrelated to and more potent than resveratrol.


Subject(s)
Oxazoles/chemical synthesis , Oxazoles/metabolism , Pyridines/chemical synthesis , Pyridines/metabolism , Sirtuins/metabolism , Animals , Bridged Bicyclo Compounds, Heterocyclic/chemical synthesis , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Enzyme Activation/drug effects , Enzyme Activation/physiology , Humans , Mice , Mice, Transgenic , Oxazoles/pharmacology , Pyridines/pharmacology , Rats , Rats, Zucker , Sirtuin 1 , Sirtuins/agonists , Structure-Activity Relationship
15.
BMC Syst Biol ; 3: 31, 2009 Mar 10.
Article in English | MEDLINE | ID: mdl-19284563

ABSTRACT

BACKGROUND: Calorie restriction (CR) produces a number of health benefits and ameliorates diseases of aging such as type 2 diabetes. The components of the pathways downstream of CR may provide intervention points for developing therapeutics for treating diseases of aging. The NAD+-dependent protein deacetylase SIRT1 has been implicated as one of the key downstream regulators of CR in yeast, rodents, and humans. Small molecule activators of SIRT1 have been identified that exhibit efficacy in animal models of diseases typically associated with aging including type 2 diabetes. To identify molecular processes induced in the liver of mice treated with two structurally distinct SIRT1 activators, SIRT501 (formulated resveratrol) and SRT1720, for three days, we utilized a systems biology approach and applied Causal Network Modeling (CNM) on gene expression data to elucidate downstream effects of SIRT1 activation. RESULTS: Here we demonstrate that SIRT1 activators recapitulate many of the molecular events downstream of CR in vivo, such as enhancing mitochondrial biogenesis, improving metabolic signaling pathways, and blunting pro-inflammatory pathways in mice fed a high fat, high calorie diet. CONCLUSION: CNM of gene expression data from mice treated with SRT501 or SRT1720 in combination with supporting in vitro and in vivo data demonstrates that SRT501 and SRT1720 produce a signaling profile that mirrors CR, improves glucose and insulin homeostasis, and acts via SIRT1 activation in vivo. Taken together these results are encouraging regarding the use of small molecule activators of SIRT1 for therapeutic intervention into type 2 diabetes, a strategy which is currently being investigated in multiple clinical trials.


Subject(s)
Caloric Restriction , Enzyme Activation/genetics , Models, Genetic , Signal Transduction/genetics , Sirtuins/metabolism , Animals , Enzyme Activation/drug effects , Gene Expression Profiling , Heterocyclic Compounds, 4 or More Rings/chemistry , Heterocyclic Compounds, 4 or More Rings/pharmacology , Mice , Microarray Analysis , Molecular Structure , Resveratrol , Signal Transduction/drug effects , Sirtuin 1 , Stilbenes/chemistry , Stilbenes/pharmacology
16.
Bioorg Med Chem Lett ; 19(5): 1416-20, 2009 Mar 01.
Article in English | MEDLINE | ID: mdl-19181526

ABSTRACT

A series of triamide derivatives bearing a benzothiazole core is shown to be potent microsomal triglyceride transfer protein (MTP) inhibitors. In order to minimize liver toxicity, these compounds have been optimized to have activity only in the enterocytes and have limited systemic bioavailability. Upon oral administration, selected analogs within this series have been further demonstrated to reduce food intake along with body weight and thereby improve glucose homeostasis and insulin sensitivity in a 28-day mice diet-induced obesity (DIO) model.


Subject(s)
Benzothiazoles/chemistry , Carrier Proteins/antagonists & inhibitors , Drug Discovery , Enterocytes/metabolism , Animals , Benzothiazoles/pharmacology , Benzothiazoles/therapeutic use , Carrier Proteins/metabolism , Cell Line, Tumor , Enterocytes/drug effects , Humans , Male , Mice , Mice, Inbred C57BL , Obesity/drug therapy , Obesity/metabolism , Rats , Rats, Sprague-Dawley
17.
J Med Chem ; 52(5): 1275-83, 2009 Mar 12.
Article in English | MEDLINE | ID: mdl-19199480

ABSTRACT

A series of imidazo[1,2-b]thiazole derivatives is shown to activate the NAD(+)-dependent deacetylase SIRT1, a potential new therapeutic target to treat various metabolic disorders. This series of compounds was derived from a high throughput screening hit bearing an oxazolopyridine core. Water-solubilizing groups could be installed conveniently at either the C-2 or C-3 position of the imidazo[1,2-b]thiazole ring. The SIRT1 enzyme activity could be adjusted by modifying the amide portion of these imidazo[1,2-b]thiazole derivatives. The most potent analogue within this series, namely, compound 29, has demonstrated oral antidiabetic activity in the ob/ob mouse model, the diet-induced obesity (DIO) mouse model, and the Zucker fa/fa rat model.


Subject(s)
Enzyme Activators/chemical synthesis , Hypoglycemic Agents/chemical synthesis , Imidazoles/chemical synthesis , Quinoxalines/chemical synthesis , Sirtuin 1/metabolism , Thiazoles/chemical synthesis , Animals , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Type 2/drug therapy , Enzyme Activators/chemistry , Enzyme Activators/pharmacology , Hypoglycemic Agents/chemistry , Hypoglycemic Agents/pharmacology , Imidazoles/chemistry , Imidazoles/pharmacology , Mice , Quinoxalines/chemistry , Quinoxalines/pharmacology , Rats , Rats, Zucker , Structure-Activity Relationship , Thiazoles/chemistry , Thiazoles/pharmacology
18.
Protein Sci ; 18(3): 514-25, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19241369

ABSTRACT

SIRT3 is a key mitochondrial protein deacetylase proposed to play key roles in regulating mitochondrial metabolism but there has been considerable debate about its actual size, the sequences required for activity, and its subcellular localization. A previously cloned mouse SIRT3 has high sequence similarity with the C-terminus of human SIRT3 but lacks an N-terminal mitochondrial targeting sequence and has no detectable deacetylation activity in vitro. Using 5' rapid amplification of cDNA ends, we cloned the entire sequence of mouse SIRT3, as well as rat and rabbit SIRT3. Importantly, we find that full-length SIRT3 protein localizes exclusively to the mitochondria, in contrast to reports of SIRT3 localization to the nucleus. We demonstrate that SIRT3 has no deacetylation activity in vitro unless the protein is truncated, consistent with human SIRT3. In addition, we determined the inhibition constants and mechanism of action for nicotinamide and a small molecule SIRT3 inhibitor against active mouse SIRT3 and show that the mechanisms are different for the two compounds with respect to peptide substrate and NAD(+). Thus, identification and characterization of the actual SIRT3 sequence should help resolve the debate about the nature of mouse SIRT3 and identify new mechanisms to modulate enzymatic activity.


Subject(s)
Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Protein Sorting Signals , Sirtuins/genetics , Sirtuins/metabolism , Tissue Distribution/genetics , Amino Acid Sequence , Animals , Base Sequence , Cells, Cultured , Cloning, Molecular , Heterocyclic Compounds, 4 or More Rings/metabolism , Mice , Mitochondria/metabolism , Mitochondrial Proteins/antagonists & inhibitors , Mitochondrial Proteins/chemistry , Molecular Sequence Data , Niacinamide/metabolism , Rabbits , Rats , Recombinant Fusion Proteins/antagonists & inhibitors , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Sequence Alignment , Sirtuin 3 , Sirtuins/antagonists & inhibitors , Sirtuins/chemistry
19.
Mol Cell Biol ; 29(5): 1363-74, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19103747

ABSTRACT

SIRT1 is a prominent member of a family of NAD(+)-dependent enzymes and affects a variety of cellular functions ranging from gene silencing, regulation of the cell cycle and apoptosis, to energy homeostasis. In mature adipocytes, SIRT1 triggers lipolysis and loss of fat content. However, the potential effects of SIRT1 on insulin signaling pathways are poorly understood. To assess this, we used RNA interference to knock down SIRT1 in 3T3-L1 adipocytes. SIRT1 depletion inhibited insulin-stimulated glucose uptake and GLUT4 translocation. This was accompanied by increased phosphorylation of JNK and serine phosphorylation of insulin receptor substrate 1 (IRS-1), along with inhibition of insulin signaling steps, such as tyrosine phosphorylation of IRS-1, and phosphorylation of Akt and ERK. In contrast, treatment of cells with specific small molecule SIRT1 activators led to an increase in glucose uptake and insulin signaling as well as a decrease in serine phosphorylation of IRS-1. Moreover, gene expression profiles showed that SIRT1 expression was inversely related to inflammatory gene expression. Finally, we show that treatment of 3T3-L1 adipocytes with a SIRT1 activator attenuated tumor necrosis factor alpha-induced insulin resistance. Taken together, these data indicate that SIRT1 is a positive regulator of insulin signaling at least partially through the anti-inflammatory actions in 3T3-L1 adipocytes.


Subject(s)
Inflammation , Insulin Resistance , Insulin/physiology , Sirtuins/physiology , 3T3-L1 Cells , Adipocytes , Animals , Glucose/metabolism , Glucose Transporter Type 4/metabolism , Insulin/metabolism , Mice , RNA Interference , Signal Transduction , Sirtuin 1
20.
Cell Metab ; 8(5): 347-58, 2008 Nov.
Article in English | MEDLINE | ID: mdl-19046567

ABSTRACT

The NAD(+)-dependent deacetylase SIRT1 controls metabolic processes in response to low nutrient availability. We report the metabolic phenotype of mice treated with SRT1720, a specific and potent synthetic activator of SIRT1 that is devoid of direct action on AMPK. SRT1720 administration robustly enhances endurance running performance and strongly protects from diet-induced obesity and insulin resistance by enhancing oxidative metabolism in skeletal muscle, liver, and brown adipose tissue. These metabolic effects of SRT1720 are mediated by the induction of a genetic network controlling fatty acid oxidation through a multifaceted mechanism that involves the direct deacetylation of PGC-1alpha, FOXO1, and p53 and the indirect stimulation of AMPK signaling through a global metabolic adaptation mimicking low energy levels. Combined with our previous work on resveratrol, the current study further validates SIRT1 as a target for the treatment of metabolic disorders and characterizes the mechanisms underlying the therapeutic potential of SIRT1 activation.


Subject(s)
Heterocyclic Compounds, 4 or More Rings/pharmacology , Lipid Metabolism/drug effects , Metabolic Diseases/metabolism , Obesity/metabolism , Sirtuins/metabolism , Acetylation , Animals , Diet , Dietary Fats/administration & dosage , Energy Metabolism , Heterocyclic Compounds, 4 or More Rings/therapeutic use , Insulin Resistance/physiology , Male , Metabolic Diseases/drug therapy , Mice , Mice, Inbred C57BL , Motor Activity/drug effects , Obesity/drug therapy , Oxidation-Reduction , Physical Conditioning, Animal , Sirtuin 1 , Sirtuins/agonists , Sirtuins/genetics
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