Institut de Biomedicina de la Universitat de Barcelona

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable childhood behavioral disorder affecting 5% of children and 2.5% of adults. Common genetic variants contribute substantially to ADHD susceptibility, but no variants have been robustly associated with ADHD. We report a genome-wide association meta-analysis of 20,183 individuals diagnosed with ADHD and 35,191 controls that identifies variants surpassing genome-wide significance in 12 independent loci, finding important new information about the underlying biology of ADHD. Associations are enriched in evolutionarily constrained genomic regions and loss-of-function intolerant genes and around brain-expressed regulatory marks. Analyses of three replication studies: a cohort of individuals diagnosed with ADHD, a self-reported ADHD sample and a meta-analysis of quantitative measures of ADHD symptoms in the population, support these findings while highlighting study-specific differences on genetic overlap with educational attainment. Strong concordance with GWAS of quantitative population measures of ADHD symptoms supports that clinical diagnosis of ADHD is an extreme expression of continuous heritable traits.

Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.

Attention-deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder with a major genetic component. Here, we present a genome-wide association study meta-analysis of ADHD comprising 38,691 individuals with ADHD and 186,843 controls. We identified 27 genome-wide significant loci, highlighting 76 potential risk genes enriched among genes expressed particularly in early brain development. Overall, ADHD genetic risk was associated with several brain-specific neuronal subtypes and midbrain dopaminergic neurons. In exome-sequencing data from 17,896 individuals, we identified an increased load of rare protein-truncating variants in ADHD for a set of risk genes enriched with probable causal common variants, potentially implicating SORCS3 in ADHD by both common and rare variants. Bivariate Gaussian mixture modeling estimated that 84-98% of ADHD-influencing variants are shared with other psychiatric disorders. In addition, common-variant ADHD risk was associated with impaired complex cognition such as verbal reasoning and a range of executive functions, including attention.

Identification of chemical compounds with specific biological activities is an important step in both chemical biology and drug discovery. When the structure of the intended target is available, one approach is to use molecular docking programs to assess the chemical complementarity of small molecules with the target; such calculations provide a qualitative measure of affinity that can be used in virtual screening (VS) to rank order a list of compounds according to their potential to be active. rDock is a molecular docking program developed at Vernalis for high-throughput VS (HTVS) applications. Evolved from RiboDock, the program can be used against proteins and nucleic acids, is designed to be computationally very efficient and allows the user to incorporate additional constraints and information as a bias to guide docking. This article provides an overview of the program structure and features and compares rDock to two reference programs, AutoDock Vina (open source) and Schrödinger's Glide (commercial). In terms of computational speed for VS, rDock is faster than Vina and comparable to Glide. For binding mode prediction, rDock and Vina are superior to Glide. The VS performance of rDock is significantly better than Vina, but inferior to Glide for most systems unless pharmacophore constraints are used; in that case rDock and Glide are of equal performance. The program is released under the Lesser General Public License and is freely available for download, together with the manuals, example files and the complete test sets, at http://rdock.sourceforge.net/

Attention-deficit/hyperactivity disorder (ADHD) is highly heritable and the most common neurodevelopmental disorder in childhood. In recent decades, it has been appreciated that in a substantial number of cases the disorder does not remit in puberty, but persists into adulthood. Both in childhood and adulthood, ADHD is characterised by substantial comorbidity including substance use, depression, anxiety, and accidents. However, course and symptoms of the disorder and the comorbidities may fluctuate and change over time, and even age of onset in childhood has recently been questioned. Available evidence to date is poor and largely inconsistent with regard to the predictors of persistence versus remittance. Likewise, the development of comorbid disorders cannot be foreseen early on, hampering preventive measures. These facts call for a lifespan perspective on ADHD from childhood to old age. In this selective review, we summarise current knowledge of the long-term course of ADHD, with an emphasis on clinical symptom and cognitive trajectories, treatment effects over the lifespan, and the development of comorbidities. Also, we summarise current knowledge and important unresolved issues on biological factors underlying different ADHD trajectories. We conclude that a severe lack of knowledge on lifespan aspects in ADHD still exists for nearly every aspect reviewed. We encourage large-scale research efforts to overcome those knowledge gaps through appropriately granular longitudinal studies.

Clear cell renal cell carcinoma (ccRCC) is histologically defined by its lipid and glycogen-rich cytoplasmic deposits. Alterations in the VHL tumor suppressor stabilizing the hypoxia-inducible factors (HIFs) are the most prevalent molecular features of clear cell tumors. The significance of lipid deposition remains undefined. We describe the mechanism of lipid deposition in ccRCC by identifying the rate-limiting component of mitochondrial fatty acid transport, carnitine palmitoyltransferase 1A (CPT1A), as a direct HIF target gene. CPT1A is repressed by HIF1 and HIF2, reducing fatty acid transport into the mitochondria, and forcing fatty acids to lipid droplets for storage. Droplet formation occurs independent of lipid source, but only when CPT1A is repressed. Functionally, repression of CPT1A is critical for tumor formation, as elevated CPT1A expression limits tumor growth. In human tumors, CPT1A expression and activity are decreased versus normal kidney; and poor patient outcome associates with lower expression of CPT1A in tumors in TCGA. Together, our studies identify HIF control of fatty acid metabolism as essential for ccRCC tumorigenesis.

Parkinson's disease (PD) is associated with the degeneration of ventral midbrain dopaminergic neurons (vmDAns) and the accumulation of toxic α-synuclein. A non-cell-autonomous contribution, in particular of astrocytes, during PD pathogenesis has been suggested by observational studies, but remains to be experimentally tested. Here, we generated induced pluripotent stem cell-derived astrocytes and neurons from familial mutant LRRK2 G2019S PD patients and healthy individuals. Upon co-culture on top of PD astrocytes, control vmDAns displayed morphological signs of neurodegeneration and abnormal, astrocyte-derived α-synuclein accumulation. Conversely, control astrocytes partially prevented the appearance of disease-related phenotypes in PD vmDAns. We additionally identified dysfunctional chaperone-mediated autophagy (CMA), impaired macroautophagy, and progressive α-synuclein accumulation in PD astrocytes. Finally, chemical enhancement of CMA protected PD astrocytes and vmDAns via the clearance of α-synuclein accumulation. Our findings unveil a crucial non-cell-autonomous contribution of astrocytes during PD pathogenesis, and open the path to exploring novel therapeutic strategies aimed at blocking the pathogenic cross talk between neurons and glial cells.

The intestine is fundamental in controlling human health. Intestinal epithelial and immune cells are continuously exposed to millions of microbes that greatly impact on intestinal epithelial barrier and immune function. This microbial community, known as gut microbiota, is now recognized as an important partner of the human being that actively contribute to essential functions of the intestine but also of distal organs. In the gut ecosystem, bidirectional microbiota-host communication does not involve direct cell contacts. Both microbiota and host-derived extracellular vesicles (EVs) are key players of such interkingdom crosstalk. There is now accumulating body of evidence that bacterial secreted vesicles mediate microbiota functions by transporting and delivering into host cells effector molecules that modulate host signalling pathways and cell processes. Consequently, vesicles released by the gut microbiota may have great influence on health and disease. Here we review current knowledge on microbiota EVs and specifically highlight their role in controlling host metabolism, intestinal barrier integrity and immune training.

Here we report that in skeletal muscle cells the contribution to insulin resistance and inflammation of two common dietary long-chain fatty acids depends on the channeling of these lipids to distinct cellular metabolic fates. Exposure of cells to the saturated fatty acid palmitate led to enhanced diacylglycerol levels and the consequent activation of the protein kinase C/nuclear factor kappaB pathway, finally resulting in enhanced interleukin 6 secretion and down-regulation of the expression of genes involved in the control of the oxidative capacity of skeletal muscle (peroxisome proliferator-activated receptor (PPAR)gamma-coactivator 1alpha) and triglyceride synthesis (acyl-coenzyme A: diacylglycerol acyltransferase 2). In contrast, exposure to the monounsaturated fatty acid oleate did not lead to these changes. Interestingly, co-incubation of cells with palmitate and oleate reversed both inflammation and impairment of insulin signaling by channeling palmitate into triglycerides and by up-regulating the expression of genes involved in mitochondrial beta-oxidation, thus reducing its incorporation into diacylglycerol. Our findings support a model of cellular lipid metabolism in which oleate protects against palmitate-induced inflammation and insulin resistance in skeletal muscle cells by promoting triglyceride accumulation and mitochondrial beta-oxidation through PPARalpha- and protein kinase A-dependent mechanisms.

Chronic kidney disease (CKD) remains a major epidemiological, clinical, and biomedical challenge. During CKD, renal tubular epithelial cells (TECs) present a persistent inflammatory and profibrotic response. Fatty acid oxidation (FAO), the main source of energy for TECs, is reduced in kidney fibrosis and contributes to its pathogenesis. To determine whether gain of function in FAO (FAO-GOF) could protect from fibrosis, we generated a conditional transgenic mouse model with overexpression of the fatty acid shuttling enzyme carnitine palmitoyl-transferase 1A (CPT1A) in TECs. Cpt1a-knockin (CPT1A-KI) mice subjected to 3 models of renal fibrosis (unilateral ureteral obstruction, folic acid nephropathy [FAN], and adenine-induced nephrotoxicity) exhibited decreased expression of fibrotic markers, a blunted proinflammatory response, and reduced epithelial cell damage and macrophage influx. Protection from fibrosis was also observed when Cpt1a overexpression was induced after FAN. FAO-GOF restored oxidative metabolism and mitochondrial number and enhanced bioenergetics, increasing palmitate oxidation and ATP levels, changes that were also recapitulated in TECs exposed to profibrotic stimuli. Studies in patients showed decreased CPT1 levels and increased accumulation of short- and middle-chain acylcarnitines, reflecting impaired FAO in human CKD. We propose that strategies based on FAO-GOF may constitute powerful alternatives to combat fibrosis inherent to CKD.

Druggability predictions are important to avoid intractable targets and to focus drug discovery efforts on sites offering better prospects. However, few druggability prediction tools have been released and none has been extensively tested. Here, a set of druggable and nondruggable cavities has been compiled in a collaborative platform ( http://fpocket.sourceforge.net/dcd ) that can be used, contributed, and curated by the community. Druggable binding sites are often oversimplified as closed, hydrophobic cavities, but data set analysis reveals that polar groups in druggable binding sites have properties that enable them to play a decisive role in ligand recognition. Finally, the data set has been used in conjunction with the open source fpocket suite to train and validate a logistic model. State of the art performance was achieved for predicting druggability on known binding sites and on virtual screening experiments where druggable pockets are retrieved from a pool of decoys. The algorithm is free, extremely fast, and can effectively be used to automatically sieve through massive collections of structures ( http://fpocket.sourceforge.net ).

Many of the comorbidities of obesity, including type 2 diabetes and cardiovascular diseases, are related to the low-grade chronic inflammation of white adipose tissue. Under white adipocyte stress, local infiltration of immune cells and enhanced production of pro-inflammatory cytokines together reduce metabolic flexibility and lead to insulin resistance in obesity. Whereas white adipocytes act in energy storage, brown and beige adipocytes specialize in energy expenditure. Brown and beige activity protects against obesity and associated metabolic disorders, such as hyperglycaemia and hyperlipidaemia. Compared to white fat, brown adipose tissue depots are less susceptible to developing local inflammation in response to obesity; however, strong obesogenic insults ultimately induce a locally pro-inflammatory environment in brown fat. This condition directly alters the thermogenic activity of brown fat by impairing its energy expenditure mechanism and uptake of glucose for use as a fuel substrate. Pro-inflammatory cytokines also impair beige adipogenesis, which occurs mainly in subcutaneous adipose tissue. There is evidence that inflammatory processes occurring in perivascular adipose tissues alter their brown-versus-white plasticity, impair the extent of browning in these depots and favour the local release of vasculature damaging signals. In summary, the targeting of brown and beige adipose tissues by pro-inflammatory signals and the subsequent impairment of their thermogenic and metabolite draining activities appears to represent obesity-driven disturbances that contribute to metabolic syndrome and cardiovascular alterations in obesity.

BACKGROUND: Adverse childhood experiences have been described as one of the major environmental risk factors for depressive disorder. Similarly, the deleterious impact of early traumatic experiences on depression seems to be moderated by individual genetic variability. Serotonin transporter (5-HTT) and brain-derived neurotrophic factor (BDNF) modulate the effect of childhood adversity on adult depression, although inconsistencies across studies have been found. Moreover, the gene x environment (GxE) interaction concerning the different types of childhood adversity remains poorly understood. The aim of this study was to analyse the putative interaction between the 5-HTT gene (5-HTTLPR polymorphism), the BDNF gene (Val66Met polymorphism) and childhood adversity in accounting for adult depressive symptoms. METHOD: A sample of 534 healthy individuals filled in self-report questionnaires of depressive symptomatology [the Symptom Check List 90 Revised (SCL-90-R)] and different types of childhood adversities [the Childhood Trauma Questionnaire (CTQ)]. The 5-HTTLPR polymorphism (5-HTT gene) and the Val66Met polymorphism (BDNF gene) were genotyped in the whole sample. RESULTS: Total childhood adversity (beta=0.27, p<0.001), childhood sexual abuse (CSA; beta=0.17, p<0.001), childhood emotional abuse (beta=0.27, p<0.001) and childhood emotional neglect (beta=0.22, p<0.001) had an impact on adult depressive symptoms. CSA had a greater impact on depressive symptoms in Met allele carriers of the BDNF gene than in the Val/Val group (F=5.87, p<0.0001), and in S carriers of the 5-HTTLPR polymorphism (5-HTT gene) (F=5.80, p<0.0001). CONCLUSIONS: Childhood adversity per se predicted higher levels of adult depressive symptoms. In addition, BDNF Val66Met and 5-HTTLPR polymorphisms seemed to moderate the effect of CSA on adult depressive symptoms.

SIRT3 is a member of the sirtuin family of protein deacetylases that is preferentially localized to mitochondria. Prominent among the proteins targeted by SIRT3 are enzymes involved in energy metabolism processes, including the respiratory chain, tricarboxylic acid cycle, fatty acid β-oxidation and ketogenesis. Through these actions, SIRT3 controls the flow of mitochondrial oxidative pathways and, consequently, the rate of production of reactive oxygen species. In addition, SIRT3-mediated deacetylation activates enzymes responsible for quenching reactive oxygen species, and thereby exerts a profound protective action against oxidative stress-dependent pathologies, such as cardiac hypertrophy and neural degeneration. SIRT3 also plays a role in multiple additional metabolic processes, from acetate metabolism to brown adipose tissue thermogenesis, often by controlling mitochondrial pathways through the deacetylation of target enzymes. In general, SIRT3 activity and subsequent control of enzymes involved in energy metabolism is consistent with an overall role of protecting against age-related diseases. In fact, experimental and genetic evidence has linked SIRT3 activity with increased lifespan. In the coming years, the identification of drugs and nutrients capable of increasing SIRT3 expression or modulating SIRT3 activity can be expected to provide promising strategies for ameliorating the metabolic syndrome and other oxidative stress-related diseases that appear preferentially with aging, such as cancer, cardiac dysfunction and neural degeneration.

Nutrient deprivation or starvation frequently correlates with amino acid limitation. Amino acid starvation initiates a signal transduction cascade starting with the activation of the kinase GCN2 (general control non-derepressible 2) phosphorylation of eIF2 (eukaryotic initiation factor 2), global protein synthesis reduction and increased ATF4 (activating transcription factor 4). ATF4 modulates a wide spectrum of genes involved in the adaptation to dietary stress. The hormone FGF21 (fibroblast growth factor 21) is induced during fasting in liver and its expression induces a metabolic state that mimics long-term fasting. Thus FGF21 is critical for the induction of hepatic fat oxidation, ketogenesis and gluconeogenesis, metabolic processes which are essential for the adaptive metabolic response to starvation. In the present study, we have shown that FGF21 is induced by amino acid deprivation in both mouse liver and cultured HepG2 cells. We have identified the human FGF21 gene as a target gene for ATF4 and we have localized two conserved ATF4-binding sequences in the 5' regulatory region of the human FGF21 gene, which are responsible for the ATF4-dependent transcriptional activation of this gene. These results add FGF21 gene induction to the transcriptional programme initiated by increased levels of ATF4 and offer a new mechanism for the induction of the FGF21 gene expression under nutrient deprivation.

In drug discovery, it is essential to identify binding sites on protein surfaces that drug-like molecules could exploit to exert a biological effect. Both X-ray crystallography and NMR experiments have demonstrated that organic solvents bind precisely at these locations. We show that this effect is reproduced using molecular dynamics with a binary solvent. Furthermore, analysis of the simulations give direct access to interaction free energies between the protein and small organic molecules, which can be used to detect binding sites and to predict the maximal affinity that a drug-like molecule could attain for them. On a set of pharmacologically relevant proteins, we obtain good predictions for druggable sites as well as for protein-protein and low affinity binding sites. This is the first druggability index not based on surface descriptors and, being independent of a training set, is particularly indicated to study unconventional targets such as protein-protein interactions or allosteric binding sites.

Nissle 1917 (EcN) is a probiotic strain with proven efficacy in inducing and maintaining remission of ulcerative colitis. However, the microbial factors that mediate these beneficial effects are not fully known. Gram-negative bacteria release outer membrane vesicles (OMVs) as a direct pathway for delivering selected bacterial proteins and active compounds to the host. In fact, vesicles released by gut microbiota are emerging as key players in signaling processes in the intestinal mucosa. In the present study, the dextran sodium sulfate (DSS)-induced colitis mouse model was used to investigate the potential of EcN OMVs to ameliorate mucosal injury and inflammation in the gut. The experimental protocol involved pre-treatment with OMVs for 10 days before DSS intake, and a 5-day recovery period. Oral administration of purified EcN OMVs (5 μg/day) significantly reduced DSS-induced weight loss and ameliorated clinical symptoms and histological scores. OMVs treatment counteracted altered expression of cytokines and markers of intestinal barrier function. This study shows for the first time that EcN OMVs can mediate the anti-inflammatory and barrier protection effects previously reported for this probiotic in experimental colitis. Remarkably, translation of probiotics to human healthcare requires knowledge of the molecular mechanisms involved in probiotic-host interactions. Thus, OMVs, as a non-replicative bacterial form, could be explored as a new probiotic-derived therapeutic approach, with even lower risk of adverse events than probiotic administration.

The genetic basis of autism spectrum disorder (ASD) is known to consist of contributions from de novo mutations in variant-intolerant genes. We hypothesize that rare inherited structural variants in cis-regulatory elements (CRE-SVs) of these genes also contribute to ASD. We investigated this by assessing the evidence for natural selection and transmission distortion of CRE-SVs in whole genomes of 9274 subjects from 2600 families affected by ASD. In a discovery cohort of 829 families, structural variants were depleted within promoters and untranslated regions, and paternally inherited CRE-SVs were preferentially transmitted to affected offspring and not to their unaffected siblings. The association of paternal CRE-SVs was replicated in an independent sample of 1771 families. Our results suggest that rare inherited noncoding variants predispose children to ASD, with differing contributions from each parent.

Regeneration and tissue repair allow damaged or lost body parts to be replaced. After injury or fragmentation of Drosophila imaginal discs, regeneration leads to the development of normal adult structures. This process is likely to involve a combination of cell rearrangement and compensatory proliferation. However, the detailed mechanisms underlying these processes are poorly understood. We have established a system to allow temporally restricted induction of cell death in situ. Using Gal4/Gal80 and UAS-rpr constructs, targeted ablation of a region of the disc could be performed and regeneration monitored without the requirement for microsurgical manipulation. Using a ptc-Gal4 construct to drive rpr expression in the wing disc resulted in a stripe of dead cells in the anterior compartment flanking the anteroposterior boundary, whereas a sal-Gal4 driver generated a dead domain that includes both anterior and posterior cells. Under these conditions, regenerated tissues were derived from the damaged compartment, suggesting that compartment restrictions are preserved during regeneration. Our studies reveal that during regeneration the live cells bordering the domain in which cell death was induced first display cytoskeletal reorganisation and apical-to-basal closure of the epithelium. Then, proliferation begins locally in the vicinity of the wound and later more extensively in the affected compartment. Finally, we show that regeneration of genetically ablated tissue requires JNK activity. During cell death-induced regeneration, the JNK pathway is activated at the leading edges of healing tissue and not in the apoptotic cells, and is required for the regulation of healing and regenerative growth.

Peroxisome proliferator activated receptor-γ co-activator-1α (PGC-1α) is a transcriptional co-activator that coordinately regulates the expression of distinct sets of metabolism-related genes in different tissues. Here we show that PGC-1α expression is reduced in skeletal muscles from mice lacking the sirtuin family deacetylase SIRT1. Conversely, SIRT1 activation or overexpression in differentiated C2C12 myotubes increased PGC-1α mRNA expression. The transcription-promoting effects of SIRT1 occurred through stimulation of PGC-1α promoter activity and were enhanced by co-transfection of myogenic factors, such as myocyte enhancer factor 2 (MEF2) and, especially, myogenic determining factor (MyoD). SIRT1 bound to the proximal promoter region of the PGC-1α gene, an interaction potentiated by MEF2C or MyoD, which also interact with this region. In the presence of MyoD, SIRT1 promoted a positive autoregulatory PGC-1α expression loop, such that overexpression of PGC-1α increased PGC-1α promoter activity in the presence of co-expressed MyoD and SIRT1. Chromatin immunoprecipitation showed that SIRT1 interacts with PGC-1α promoter and increases PGC-1α recruitment to its own promoter region. Immunoprecipitation assays further showed that SIRT1-PGC-1α interactions are enhanced by MyoD. Collectively, these data indicate that SIRT1 controls PGC-1α gene expression in skeletal muscle and that MyoD is a key mediator of this action. The involvement of MyoD in SIRT1-dependent PGC-1α expression may help to explain the ability of SIRT1 to drive muscle-specific gene expression and metabolism. Autoregulatory control of PGC-1α gene transcription seems to be a pivotal mechanism for conferring a transcription-activating response to SIRT1 in skeletal muscle. Peroxisome proliferator activated receptor-γ co-activator-1α (PGC-1α) is a transcriptional co-activator that coordinately regulates the expression of distinct sets of metabolism-related genes in different tissues. Here we show that PGC-1α expression is reduced in skeletal muscles from mice lacking the sirtuin family deacetylase SIRT1. Conversely, SIRT1 activation or overexpression in differentiated C2C12 myotubes increased PGC-1α mRNA expression. The transcription-promoting effects of SIRT1 occurred through stimulation of PGC-1α promoter activity and were enhanced by co-transfection of myogenic factors, such as myocyte enhancer factor 2 (MEF2) and, especially, myogenic determining factor (MyoD). SIRT1 bound to the proximal promoter region of the PGC-1α gene, an interaction potentiated by MEF2C or MyoD, which also interact with this region. In the presence of MyoD, SIRT1 promoted a positive autoregulatory PGC-1α expression loop, such that overexpression of PGC-1α increased PGC-1α promoter activity in the presence of co-expressed MyoD and SIRT1. Chromatin immunoprecipitation showed that SIRT1 interacts with PGC-1α promoter and increases PGC-1α recruitment to its own promoter region. Immunoprecipitation assays further showed that SIRT1-PGC-1α interactions are enhanced by MyoD. Collectively, these data indicate that SIRT1 controls PGC-1α gene expression in skeletal muscle and that MyoD is a key mediator of this action. The involvement of MyoD in SIRT1-dependent PGC-1α expression may help to explain the ability of SIRT1 to drive muscle-specific gene expression and metabolism. Autoregulatory control of PGC-1α gene transcription seems to be a pivotal mechanism for conferring a transcription-activating response to SIRT1 in skeletal muscle. Peroxisome proliferator activated receptor-γ co-activator-1α (PGC-1α) 2The abbreviations used are: PGC-1αperoxisome proliferator activated receptor-γco-activator-1αUCP1uncoupling protein 1UCP3uncoupling protein 3NAMnicotinamideChIPchromatin immunoprecipitationMyoDmyogenic determining factorPPARγperoxisome proliferator activated receptor-γGFPgreen fluorescent proteinCMVcytomegalovirusMEF2myocyte enhancer factor 2. 2The abbreviations used are: PGC-1αperoxisome proliferator activated receptor-γco-activator-1αUCP1uncoupling protein 1UCP3uncoupling protein 3NAMnicotinamideChIPchromatin immunoprecipitationMyoDmyogenic determining factorPPARγperoxisome proliferator activated receptor-γGFPgreen fluorescent proteinCMVcytomegalovirusMEF2myocyte enhancer factor 2. is a transcriptional co-activator that is recognized as a master controller of the expression of genes involved in metabolic regulation. PGC-1α exerts differential effects on metabolism in different tissues. In brown adipose tissue, PGC-1α increases the expression of uncoupling protein 1 and genes involved in mitochondrial oxidative pathways. In the liver, PGC-1α induces the expression of genes involved in gluconeogenesis and the metabolic response to starvation. In skeletal muscle, PGC-1α expression is rapidly induced by exercise in vivo (1Pilegaard H. Saltin B. Neufer P.D. Diabetes. 2003; 52: 657-662Crossref PubMed Scopus (121) Google Scholar), a response considered to be a mechanism for modulating metabolic flux in response to decreased ATP levels (2Russell A.P. Feilchenfeldt J. Schreiber S. Praz M. Crettenand A. Gobelet C. Meier C.A. Bell D.R. Kralli A. Giacobino J.P. Dériaz O. Diabetes. 2003; 52: 2874-2881Crossref PubMed Scopus (368) Google Scholar). Chronic exercise also increases PGC-1α expression in association with fiber-type switching toward the more oxidative and high endurance type IIa and type I fibers. The fiber-type switch promoted by PGC-1α is characterized by increased mitochondrial density and function, increased oxidative metabolism, increased expression of myofibrillar proteins characteristic of type I and type IIa muscle fibers and a switch in substrate fuel usage (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar). Furthermore, greater levels of PGC-1α are found in oxidative fibers compared with glycolytic fibers, even in a rested state (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar). Moreover, PGC-1α gene transcription is positively controlled by myogenic transcription factors, such as MyoD and MEF2 (4Chang J.H. Lin K.H. Shih C.H. Chang Y.J. Chi H.C. Chen S.L. Endocrinology. 2006; 147: 3093-3106Crossref PubMed Scopus (24) Google Scholar, 5Handschin C. Rhee J. Lin J. Tarr P.T. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7111-7116Crossref PubMed Scopus (574) Google Scholar, 6Czubryt M.P. McAnally J. Fishman G.I. Olson E.N. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 1711-1716Crossref PubMed Scopus (335) Google Scholar).The action of PGC-1α is modulated by post-translation modifications (7Handschin C. Spiegelman B.M. Endocr. Rev. 2006; 27: 728-735Crossref PubMed Scopus (865) Google Scholar, 8Jäger S. Handschin C. St-Pierre J. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2007; 104: 12017-12022Crossref PubMed Scopus (1749) Google Scholar) such as acetylation (see below), or as a consequence of a strong transcriptional regulation of the PGC-1α gene by hormonal and metabolic stimuli that result in changes in PGC-1α levels, and therefore PGC-1α activity. Depending on the tissue and cell type, PGC-1α gene expression is regulated by cAMP-mediated pathways, peroxisome proliferator activated receptor-γ (PPARγ) and -β/δ (PPARβ/δ) activation, as well as the calcium-calmodulin pathway (7Handschin C. Spiegelman B.M. Endocr. Rev. 2006; 27: 728-735Crossref PubMed Scopus (865) Google Scholar).SIRT1 is a member of the sirtuin family of protein deacetylases, which have a major role in metabolic regulation. SIRT1 deacetylates histones as well as transcription factors and co-regulators and thereby controls regulatory protein activity and, ultimately, gene expression. The deacetylase activity of SIRT1 is controlled by the NAD+/NADH ratio, thus SIRT1 is considered to act as a sensor of the metabolic status of the cell and mediates adaptive gene expression in response to metabolic changes.SIRT1 has been reported to exert negative control of myogenesis through deacetylation and subsequent repression of MyoD, particularly in association with the high NAD+ levels characteristic of myoblasts (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar) and under conditions of glucose restriction (10Fulco M. Cen Y. Zhao P. Hoffman E.P. McBurney M.W. Sauve A.A. Sartorelli V. Dev. Cell. 2008; 14: 661-673Abstract Full Text Full Text PDF PubMed Scopus (605) Google Scholar). Moreover, SIRT1 represses the expression of metabolic genes such as uncoupling protein 3 (ucp3), which is a direct target of MyoD regulation (11Amat R. Solanes G. Giralt M. Villarroya F. J. Biol. Chem. 2007; 282: 34066-34076Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar, 12Solanes G. Pedraza N. Iglesias R. Giralt M. Villarroya F. FASEB J. 2000; 14: 2141-2143Crossref PubMed Scopus (48) Google Scholar). Recent studies have also revealed that SIRT1 deacetylates PGC-1α in skeletal muscle, a modification that is associated with up-regulation of the fatty acid oxidation gene program in skeletal muscle (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar). of mice with SIRT1 or increases PGC-1α in an in PGC-1α activity and transcription of PGC-1α target In to SIRT1 have also been reported to PGC-1α levels M. C. Z. H. Lerin C. F. N. J. P. P. B. M. Puigserver P. J. Cell. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, M. C. A. P.D. C. J. 2008; Full Text Full Text PDF PubMed Scopus Google the we the role of SIRT1 in PGC-1α gene expression in skeletal muscle that SIRT1 increases PGC-1α gene an that PGC-1α autoregulatory and the interaction of SIRT1 with myogenic transcription The direct control of PGC-1α gene and thus PGC-1α levels and by SIRT1 may be a key in the regulatory that metabolic changes to adaptive gene expression in skeletal this we have a pathway in which SIRT1 action positively regulated PGC-1α gene transcription in skeletal muscle. a in which SIRT1 interacts with and deacetylates its activity on its own promoter through interactions with MyoD. The result is a positive autoregulatory to in the control of muscle metabolism, the effects of SIRT1 on PGC-1α gene expression of muscle gene transcription regulation by that SIRT1 positively regulates PGC-1α gene expression in with MyoD is a of SIRT1 represses the action of MyoD on its target as by (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar). in the of the PGC-1α gene, the positive of SIRT1 is to a of the transcriptional and the of positive autoregulatory by PGC-1α indicate that which has been reported to effects of SIRT1 on gene transcription (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar), have an role in the control of the PGC-1α gene The of a autoregulatory and the that PGC-1α activity is increased by deacetylation by SIRT1 (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar) are with the positive of SIRT1 on the transcriptional regulatory MyoD and the transcription of MyoD target gene, in which PGC-1α exert positive effects (11Amat R. Solanes G. Giralt M. Villarroya F. J. Biol. Chem. 2007; 282: 34066-34076Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar), is by SIRT1. Moreover, the of its own gene promoter has been reported and to be by E. Iglesias R. B. Villarroya F. Giralt M. 2007; PubMed Scopus Google Scholar, E. O. P. M. Iglesias R. Giralt M. Villarroya F. Endocrinology. 2006; 147: PubMed Scopus Google Scholar) or the myogenic factor MEF2C C. Rhee J. Lin J. Tarr P.T. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7111-7116Crossref PubMed Scopus (574) Google Scholar, 6Czubryt M.P. McAnally J. Fishman G.I. Olson E.N. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 1711-1716Crossref PubMed Scopus (335) Google Scholar), as also found in the In of the be that muscle genes that are of positive activation by MyoD and PGC-1α be positively regulated by SIRT1. data this SIRT1 seems to the gene and F. a positive target of myogenic factors and PGC-1α (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar, A. J. PubMed Scopus Google Scholar).The transcriptional control of PGC-1α gene expression by SIRT1 adaptive gene expression in response to metabolic stimuli by PGC-1α expression and, PGC-1α target mechanism be to the action reported by in which SIRT1 has to PGC-1α target genes by thereby its activity. SIRT1 the that its be to act through enhanced expression and enhanced activity of to control a of genes in skeletal muscle, oxidative metabolism, and to the of oxidative in muscle. that the expression levels of PGC-1α (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar, M. Chen M. FASEB J. 2002; PubMed Scopus Google Scholar) and SIRT1 M. H. Z. S. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar) are increased in oxidative muscle fibers to glycolytic fibers are with the restriction has been reported to the in skeletal muscle oxidative FASEB J. PubMed Scopus Google Scholar, J. Biol. Sci. Sci. 2006; PubMed Scopus Google Scholar). The of PGC-1α by SIRT1 and subsequent of mitochondrial oxidative metabolism to this positive of In we that SIRT1 controls PGC-1α gene expression in skeletal muscle and MyoD is a key mediator of this action. The involvement of myogenic factors in SIRT1 action on PGC-1α may a mechanism to help explain SIRT1 muscle-specific adaptive changes in gene expression and metabolism. Peroxisome proliferator activated receptor-γ co-activator-1α (PGC-1α) 2The abbreviations used are: PGC-1αperoxisome proliferator activated receptor-γco-activator-1αUCP1uncoupling protein 1UCP3uncoupling protein 3NAMnicotinamideChIPchromatin immunoprecipitationMyoDmyogenic determining factorPPARγperoxisome proliferator activated receptor-γGFPgreen fluorescent proteinCMVcytomegalovirusMEF2myocyte enhancer factor 2. 2The abbreviations used are: PGC-1αperoxisome proliferator activated receptor-γco-activator-1αUCP1uncoupling protein 1UCP3uncoupling protein 3NAMnicotinamideChIPchromatin immunoprecipitationMyoDmyogenic determining factorPPARγperoxisome proliferator activated receptor-γGFPgreen fluorescent proteinCMVcytomegalovirusMEF2myocyte enhancer factor 2. is a transcriptional co-activator that is recognized as a master controller of the expression of genes involved in metabolic regulation. PGC-1α exerts differential effects on metabolism in different tissues. In brown adipose tissue, PGC-1α increases the expression of uncoupling protein 1 and genes involved in mitochondrial oxidative pathways. In the liver, PGC-1α induces the expression of genes involved in gluconeogenesis and the metabolic response to starvation. In skeletal muscle, PGC-1α expression is rapidly induced by exercise in vivo (1Pilegaard H. Saltin B. Neufer P.D. Diabetes. 2003; 52: 657-662Crossref PubMed Scopus (121) Google Scholar), a response considered to be a mechanism for modulating metabolic flux in response to decreased ATP levels (2Russell A.P. Feilchenfeldt J. Schreiber S. Praz M. Crettenand A. Gobelet C. Meier C.A. Bell D.R. Kralli A. Giacobino J.P. Dériaz O. Diabetes. 2003; 52: 2874-2881Crossref PubMed Scopus (368) Google Scholar). Chronic exercise also increases PGC-1α expression in association with fiber-type switching toward the more oxidative and high endurance type IIa and type I fibers. The fiber-type switch promoted by PGC-1α is characterized by increased mitochondrial density and function, increased oxidative metabolism, increased expression of myofibrillar proteins characteristic of type I and type IIa muscle fibers and a switch in substrate fuel usage (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar). Furthermore, greater levels of PGC-1α are found in oxidative fibers compared with glycolytic fibers, even in a rested state (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar). Moreover, PGC-1α gene transcription is positively controlled by myogenic transcription factors, such as MyoD and MEF2 (4Chang J.H. Lin K.H. Shih C.H. Chang Y.J. Chi H.C. Chen S.L. Endocrinology. 2006; 147: 3093-3106Crossref PubMed Scopus (24) Google Scholar, 5Handschin C. Rhee J. Lin J. Tarr P.T. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7111-7116Crossref PubMed Scopus (574) Google Scholar, 6Czubryt M.P. McAnally J. Fishman G.I. Olson E.N. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 1711-1716Crossref PubMed Scopus (335) Google Scholar). peroxisome proliferator activated uncoupling protein 1 uncoupling protein 3 immunoprecipitation myogenic determining factor peroxisome proliferator activated receptor-γ fluorescent protein myocyte enhancer factor 2. peroxisome proliferator activated uncoupling protein 1 uncoupling protein 3 immunoprecipitation myogenic determining factor peroxisome proliferator activated receptor-γ fluorescent protein myocyte enhancer factor 2. The action of PGC-1α is modulated by post-translation modifications (7Handschin C. Spiegelman B.M. Endocr. Rev. 2006; 27: 728-735Crossref PubMed Scopus (865) Google Scholar, 8Jäger S. Handschin C. St-Pierre J. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2007; 104: 12017-12022Crossref PubMed Scopus (1749) Google Scholar) such as acetylation (see below), or as a consequence of a strong transcriptional regulation of the PGC-1α gene by hormonal and metabolic stimuli that result in changes in PGC-1α levels, and therefore PGC-1α activity. Depending on the tissue and cell type, PGC-1α gene expression is regulated by cAMP-mediated pathways, peroxisome proliferator activated receptor-γ (PPARγ) and -β/δ (PPARβ/δ) activation, as well as the calcium-calmodulin pathway (7Handschin C. Spiegelman B.M. Endocr. Rev. 2006; 27: 728-735Crossref PubMed Scopus (865) Google Scholar). SIRT1 is a member of the sirtuin family of protein deacetylases, which have a major role in metabolic regulation. SIRT1 deacetylates histones as well as transcription factors and co-regulators and thereby controls regulatory protein activity and, ultimately, gene expression. The deacetylase activity of SIRT1 is controlled by the NAD+/NADH ratio, thus SIRT1 is considered to act as a sensor of the metabolic status of the cell and mediates adaptive gene expression in response to metabolic SIRT1 has been reported to exert negative control of myogenesis through deacetylation and subsequent repression of MyoD, particularly in association with the high NAD+ levels characteristic of myoblasts (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar) and under conditions of glucose restriction (10Fulco M. Cen Y. Zhao P. Hoffman E.P. McBurney M.W. Sauve A.A. Sartorelli V. Dev. Cell. 2008; 14: 661-673Abstract Full Text Full Text PDF PubMed Scopus (605) Google Scholar). Moreover, SIRT1 represses the expression of metabolic genes such as uncoupling protein 3 (ucp3), which is a direct target of MyoD regulation (11Amat R. Solanes G. Giralt M. Villarroya F. J. Biol. Chem. 2007; 282: 34066-34076Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar, 12Solanes G. Pedraza N. Iglesias R. Giralt M. Villarroya F. FASEB J. 2000; 14: 2141-2143Crossref PubMed Scopus (48) Google Scholar). Recent studies have also revealed that SIRT1 deacetylates PGC-1α in skeletal muscle, a modification that is associated with up-regulation of the fatty acid oxidation gene program in skeletal muscle (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar). of mice with SIRT1 or increases PGC-1α in an in PGC-1α activity and transcription of PGC-1α target In to SIRT1 have also been reported to PGC-1α levels M. C. Z. H. Lerin C. F. N. J. P. P. B. M. Puigserver P. J. Cell. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, M. C. A. P.D. C. J. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar). In the we the role of SIRT1 in PGC-1α gene expression in skeletal muscle that SIRT1 increases PGC-1α gene an that PGC-1α autoregulatory and the interaction of SIRT1 with myogenic transcription The direct control of PGC-1α gene and thus PGC-1α levels and by SIRT1 may be a key in the regulatory that metabolic changes to adaptive gene expression in skeletal muscle. this we have a pathway in which SIRT1 action positively regulated PGC-1α gene transcription in skeletal muscle. a in which SIRT1 interacts with and deacetylates its activity on its own promoter through interactions with MyoD. The result is a positive autoregulatory to in the control of muscle metabolism, the effects of SIRT1 on PGC-1α gene expression of muscle gene transcription regulation by that SIRT1 positively regulates PGC-1α gene expression in with MyoD is a of SIRT1 represses the action of MyoD on its target as by (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar). in the of the PGC-1α gene, the positive of SIRT1 is to a of the transcriptional and the of positive autoregulatory by PGC-1α indicate that which has been reported to effects of SIRT1 on gene transcription (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar), have an role in the control of the PGC-1α gene The of a autoregulatory and the that PGC-1α activity is increased by deacetylation by SIRT1 (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar) are with the positive of SIRT1 on the transcriptional regulatory MyoD and the transcription of MyoD target gene, in which PGC-1α exert positive effects (11Amat R. Solanes G. Giralt M. Villarroya F. J. Biol. Chem. 2007; 282: 34066-34076Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar), is by SIRT1. Moreover, the of its own gene promoter has been reported and to be by E. Iglesias R. B. Villarroya F. Giralt M. 2007; PubMed Scopus Google Scholar, E. O. P. M. Iglesias R. Giralt M. Villarroya F. Endocrinology. 2006; 147: PubMed Scopus Google Scholar) or the myogenic factor MEF2C C. Rhee J. Lin J. Tarr P.T. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7111-7116Crossref PubMed Scopus (574) Google Scholar, 6Czubryt M.P. McAnally J. Fishman G.I. Olson E.N. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 1711-1716Crossref PubMed Scopus (335) Google Scholar), as also found in the In of the be that muscle genes that are of positive activation by MyoD and PGC-1α be positively regulated by SIRT1. data this SIRT1 seems to the gene and F. a positive target of myogenic factors and PGC-1α (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar, A. J. PubMed Scopus Google Scholar).The transcriptional control of PGC-1α gene expression by SIRT1 adaptive gene expression in response to metabolic stimuli by PGC-1α expression and, PGC-1α target mechanism be to the action reported by in which SIRT1 has to PGC-1α target genes by thereby its activity. SIRT1 the that its be to act through enhanced expression and enhanced activity of to control a of genes in skeletal muscle, oxidative metabolism, and to the of oxidative in muscle. that the expression levels of PGC-1α (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar, M. Chen M. FASEB J. 2002; PubMed Scopus Google Scholar) and SIRT1 M. H. Z. S. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar) are increased in oxidative muscle fibers to glycolytic fibers are with the restriction has been reported to the in skeletal muscle oxidative FASEB J. PubMed Scopus Google Scholar, J. Biol. Sci. Sci. 2006; PubMed Scopus Google Scholar). The of PGC-1α by SIRT1 and subsequent of mitochondrial oxidative metabolism to this positive of In we that SIRT1 controls PGC-1α gene expression in skeletal muscle and MyoD is a key mediator of this action. The involvement of myogenic factors in SIRT1 action on PGC-1α may a mechanism to help explain SIRT1 muscle-specific adaptive changes in gene expression and metabolism. In this we have a pathway in which SIRT1 action positively regulated PGC-1α gene transcription in skeletal muscle. a in which SIRT1 interacts with and deacetylates its activity on its own promoter through interactions with MyoD. The result is a positive autoregulatory In to in the control of muscle metabolism, the effects of SIRT1 on PGC-1α gene expression of muscle gene transcription regulation by SIRT1. The that SIRT1 positively regulates PGC-1α gene expression in with MyoD is a of SIRT1 represses the action of MyoD on its target as by (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar). in the of the PGC-1α gene, the positive of SIRT1 is to a of the transcriptional and the of positive autoregulatory by PGC-1α indicate that which has been reported to effects of SIRT1 on gene transcription (9Fulco M. Schiltz R.L. Iezzi S. King M.T. Zhao P. Kashiwaya Y. Hoffman E. Veech R.L. Sartorelli V. Mol. Cell. 2003; 12: 51-62Abstract Full Text Full Text PDF PubMed Scopus (503) Google Scholar), have an role in the control of the PGC-1α gene The of a autoregulatory and the that PGC-1α activity is increased by deacetylation by SIRT1 (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar) are with the positive of SIRT1 on the transcriptional regulatory MyoD and the transcription of MyoD target gene, in which PGC-1α exert positive effects (11Amat R. Solanes G. Giralt M. Villarroya F. J. Biol. Chem. 2007; 282: 34066-34076Abstract Full Text Full Text PDF PubMed Scopus (69) Google Scholar), is by SIRT1. Moreover, the of its own gene promoter has been reported and to be by E. Iglesias R. B. Villarroya F. Giralt M. 2007; PubMed Scopus Google Scholar, E. O. P. M. Iglesias R. Giralt M. Villarroya F. Endocrinology. 2006; 147: PubMed Scopus Google Scholar) or the myogenic factor MEF2C C. Rhee J. Lin J. Tarr P.T. Spiegelman B.M. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 7111-7116Crossref PubMed Scopus (574) Google Scholar, 6Czubryt M.P. McAnally J. Fishman G.I. Olson E.N. Proc. Natl. Acad. Sci. U.S.A. 2003; 100: 1711-1716Crossref PubMed Scopus (335) Google Scholar), as also found in the In of the be that muscle genes that are of positive activation by MyoD and PGC-1α be positively regulated by SIRT1. data this SIRT1 seems to the gene and F. a positive target of myogenic factors and PGC-1α (13Gerhart-Hines Z. Rodgers J.T. Bare O. Lerin C. Kim S.H. Mostoslavsky R. Wu Z. Puigserver P. J. 2007; PubMed Scopus Google Scholar, A. J. PubMed Scopus Google Scholar). The transcriptional control of PGC-1α gene expression by SIRT1 adaptive gene expression in response to metabolic stimuli by PGC-1α expression and, PGC-1α target mechanism be to the action reported by in which SIRT1 has to PGC-1α target genes by thereby its activity. SIRT1 the that its be to act through enhanced expression and enhanced activity of to control a of genes in skeletal muscle, oxidative metabolism, and to the of oxidative in muscle. that the expression levels of PGC-1α (3Lin J. Wu H. Tarr P.T. Zhang C.Y. Wu Z. Boss O. Michael L.F. Puigserver P. Isotani E. Olson E.N. Lowell B.B. Bassel-Duby R. Spiegelman B.M. Nature. 2002; 418: 797-801Crossref PubMed Scopus (2018) Google Scholar, M. Chen M. FASEB J. 2002; PubMed Scopus Google Scholar) and SIRT1 M. H. Z. S. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar) are increased in oxidative muscle fibers to glycolytic fibers are with the restriction has been reported to the in skeletal muscle oxidative FASEB J. PubMed Scopus Google Scholar, J. Biol. Sci. Sci. 2006; PubMed Scopus Google Scholar). The of PGC-1α by SIRT1 and subsequent of mitochondrial oxidative metabolism to this positive of In we that SIRT1 controls PGC-1α gene expression in skeletal muscle and MyoD is a key mediator of this action. The involvement of myogenic factors in SIRT1 action on PGC-1α may a mechanism to help explain SIRT1 muscle-specific adaptive changes in gene expression and metabolism. M. B. and P. Puigserver for expression and F. for