White Bars Research Articles

Maintenance of phenotypic variation: repeatability, heritability and size-dependent processes in a wild brook trout population.

Phenotypic variation in body size can result from within-cohort variation in birth dates, among-individual growth variation and size-selective processes. We explore the relative effects of these processes on the maintenance of wide observed body size variation in stream-dwelling brook trout (Salvelinus fontinalis). Based on the analyses of multiple recaptures of individual fish, it appears that size distributions are largely determined by the maintenance of early size variation. We found no evidence for size-dependent compensatory growth (which would reduce size variation) and found no indication that size-dependent survival substantially influenced body size distributions. Depensatory growth (faster growth by larger individuals) reinforced early size variation, but was relatively strong only during the first sampling interval (age-0, fall). Maternal decisions on the timing and location of spawning could have a major influence on early, and as our results suggest, later (>age-0) size distributions. If this is the case, our estimates of heritability of body size (body length = 0.25) will be dominated by processes that generate and maintain early size differences. As a result, evolutionary responses to environmental change that are mediated by body size may be largely expressed via changes in the timing and location of reproduction.

Intracranial hemorrhage after high-dose methylprednisolone in a child with acute immune thrombocytopenic purpura

Dear Editor, Severe hemorrhage in children with immune thrombocytopenic purpura (ITP) is rare and occurs in 3% of patients [1]. Intracranial hemorrhage (ICH), the most feared bleeding complication, has an estimated incidence of 0.1–0.5% [1–3]. Mortality rate of ICH is high and varies from 24–57% [2–4]. We report a patient with acute ITP who developed fatal ICH shortly after starting high-dose methylprednisolone. A 5-year-old girl with an unremarkable medical and family history presented to her pediatrician with acute onset of bruising and petechiae. Physical examination revealed no other abnormalities. Blood pressure was 112/60 mmHg. Laboratory studies showed an isolated trombocytopenia of 1 × 109/L (Table 1). She was diagnosed with acute ITP and managed conservatively. Four days after presentation, she developed large ecchymoses and epistaxis causing anemia. Intravenous immunoglobulins (IVIg; 0.8 g/kg once) and packed red cells were administered (Fig. 1). Platelet count remained low (1 × 109/L) and mucosal bleeding continued. The girl was referred to our department for further management. We saw a pale, tachycardic girl with multiple ecchymoses and active mucosal bleeding from nose and mouth. Hemoglobin was 7.4 g/dL and platelet count 2 × 109/L. After a second gift of IVIg, prednisone 2 mg/kg/day, an erythrocyte transfusion and a large dose of platelets (ten donor units), platelet count rose to 21 × 109/L, hemoglobin stabilized and the clinical condition of our patient improved dramatically. However, 36 h later, profuse mucosal bleeding from nose and mouth recurred at a platelet count of 1 × 109/L. We started high-dose methylprednisolone (15 mg/kg) together with another platelet transfusion. Shortly after starting the methylprednisolone infusion, she complained of severe headache and instantly developed generalized seizures. Blood pressure at that moment was elevated: 170/90 mmHg. Computed tomography (CT) showed extensive bifrontal ICH. Unfortunately, our patient died of progressive herniation caused by massive cerebral edema, despite continuous platelet transfusions and intensive care management. Autopsy was not performed. Table 1 Results of laboratory studies in our patient Fig. 1 Overview of platelet counts and interventions in our patient. i = IVIg; white bar = prednisone 2 mg/kg/day; white arrow = high-dose methylprednisolone infusion; black circle = platelet transfusion; black diamond = erythrocyte transfusion. ... The main reason for clinicians to treat children with acute ITP and minor bleeding symptoms is to raise platelet counts in order to prevent severe bleeding complications and in particular ICH. The question is whether treatment really prevents these bleeding complications. The majority of children with severe bleeding or ICH described in literature developed these complications despite prior therapy [1–5]. Why do some patients develop ICH despite therapy? Apart from known risk factors like head trauma, use of non-steroidal anti-inflammatory drugs, intracranial arteriovenous malformation, and bleeding beyond petechiae and ecchymoses [2, 3], there are some other possible explanations. Patients may suffer from refractory ITP and remain severely thrombocytopenic despite therapy, leaving them at risk for bleeding complications [6]. However, there is also a possibility of either causing or worsening ICH due to adverse effects of drug therapy. In our patient, the temporal relationship between starting methylprednisolone and development of headache and ICH remains remarkable. A sudden rise in blood pressure, a known adverse effect of high-dose methylprednisolone, could have initiated or worsened ICH. In conclusion, this report shows that treatment of ITP cannot always prevent ICH and may even be involved in initiating or worsening ICH.

The conserved factor DE-ETIOLATED 1 cooperates with CUL4-DDB1DDB2to maintain genome integrity upon UV stress

Plants and many other eukaryotes can make use of two major pathways to cope with mutagenic effects of light, photoreactivation and nucleotide excision repair (NER). While photoreactivation allows direct repair by photolyase enzymes using light energy, NER requires a stepwise mechanism with several protein complexes acting at the levels of lesion detection, DNA incision and resynthesis. Here we investigated the involvement in NER of DE-ETIOLATED 1 (DET1), an evolutionarily conserved factor that associates with components of the ubiquitylation machinery in plants and mammals and acts as a negative repressor of light-driven photomorphogenic development in Arabidopsis. Evidence is provided that plant DET1 acts with CULLIN4-based ubiquitin E3 ligase, and that appropriate dosage of DET1 protein is necessary for efficient removal of UV photoproducts through the NER pathway. Moreover, DET1 is required for CULLIN4-dependent targeted degradation of the UV-lesion recognition factor DDB2. Finally, DET1 protein is degraded concomitantly with DDB2 upon UV irradiation in a CUL4-dependent mechanism. Altogether, these data suggest that DET1 and DDB2 cooperate during the excision repair process.

Ameliorative effect of NAP on laser-induced retinal damage

NAP is the smallest active element of activity-dependent neuroprotective protein (ADNP) in the non-myelinated neural tissue. This study evaluated the neuroprotective effect of NAP in reducing the spread of laser-induced retinal damage in rat. Laser lesions were created in 72 DA pigmented rats. Two groups were treated by one intravenous or intravitreal injection of NAP immediately after exposure to laser. Two control groups were similarly administered saline injection. Histological and morphometrical evaluations of the lesions were preformed 3, 20 and 60 days after photocoagulation. After intravitreal treatment with NAP, a significant reduction in the diameter of the laser-induced lesions was found 3 days after photocoagulation (p < 0.001) but not after 20 and 60 days while the systemic treatment significantly reduced lesion diameter 20 and 60 days after photocoagulation (p = 0.001). Significant difference in photoreceptor cell loss was found in eyes treated intravitreally only 3 days after photocoagulation (p = 0.002). In the systemically treated animals such effect was found only after 20 and 60 days (p < 0.001). Treatment with NAP ameliorates laser-induced retinal lesions. Intravitreal treatment had an early short-term effect while the effect of systemic administration was delayed and prolonged. This treatment may be of clinical significance in reducing laser-induced retinal injuries in humans.

Long-term Retinal Function and Structure Rescue Using Capsid Mutant AAV8 Vector in the rd10 Mouse, a Model of Recessive Retinitis Pigmentosa

The retinal degeneration 10 (rd10) mouse is a well-characterized model of autosomal recessive retinitis pigmentosa (RP), which carries a spontaneous mutation in the β subunit of rod cGMP-phosphodiesterase (PDEβ). Rd10 mouse exhibits photoreceptor dysfunction and rapid rod photoreceptor degeneration followed by cone degeneration and remodeling of the inner retina. Here, we evaluate whether gene replacement using the fast-acting tyrosine-capsid mutant AAV8 (Y733F) can provide long-term therapy in this model. AAV8 (Y733F)-smCBA-PDEβ was subretinally delivered to postnatal day 14 (P14) rd10 mice in one eye only. Six months after injection, spectral domain optical coherence tomography (SD-OCT), electroretinogram (ERG), optomotor behavior tests, and immunohistochemistry showed that AAV8 (Y733F)-mediated PDEβ expression restored retinal function and visual behavior and preserved retinal structure in treated rd10 eyes for at least 6 months. This is the first demonstration of long-term phenotypic rescue by gene therapy in an animal model of PDEβ-RP. It is also the first example of tyrosine-capsid mutant AAV8 (Y733F)-mediated correction of a retinal phenotype. These results lay the groundwork for the development of PDEβ-RP gene therapy trial and suggest that tyrosine-capsid mutant AAV vectors may be effective for treating other rapidly degenerating models of retinal degeneration.

MiRNAs control insulin content in pancreatic β-cells via downregulation of transcriptional repressors

MicroRNAs (miRNAs) were shown to be important for pancreas development, yet their roles in differentiated β-cells remain unclear. Here, we show that miRNA inactivation in β-cells of adult mice results in a striking diabetic phenotype. While islet architecture is intact and differentiation markers are maintained, Dicer1-deficient β-cells show a dramatic decrease in insulin content and insulin mRNA. As a consequence of the change in insulin content, the animals become diabetic. We provide evidence for involvement of a set of miRNAs in regulating insulin synthesis. The specific knockdown of miR-24, miR-26, miR-182 or miR-148 in cultured β-cells or in isolated primary islets downregulates insulin promoter activity and insulin mRNA levels. Further, miRNA-dependent regulation of insulin expression is associated with upregulation of transcriptional repressors, including Bhlhe22 and Sox6. Thus, miRNAs in the adult pancreas act in a new network that reinforces insulin expression by reducing the expression of insulin transcriptional repressors.

A loss‐of‐function variant of the antiviral molecule MAVS is associated with a subset of systemic lupus patients

Dysregulation of the antiviral immune response may contribute to autoimmune diseases. Here, we hypothesized that altered expression or function of MAVS, a key molecule downstream of the viral sensors RIG-I and MDA-5, may impair antiviral cell signalling and thereby influence the risk for systemic lupus erythematosus (SLE), the prototype autoimmune disease. We used molecular techniques to screen non-synonymous single nucleotide polymorphisms (SNPs) in the MAVS gene for functional significance in human cell lines and identified one critical loss-of-function variant (C79F, rs11905552). This SNP substantially reduced expression of type I interferon (IFN) and other proinflammatory mediators and was found almost exclusively in the African-American population. Importantly, in African-American SLE patients, the C79F allele was associated with low type I IFN production and absence of anti-RNA-binding protein autoantibodies. These serologic associations were not related to a distinct, functionally neutral, MAVS SNP Q198K. Hence, this is the first demonstration that an uncommon genetic variant in the MAVS gene has a functional impact upon the anti-viral IFN pathway in vivo in humans and is associated with a novel sub-phenotype in SLE. This study demonstrates the utility of functional data in selecting rare variants for genetic association studies, allowing for fewer comparisons requiring statistical correction and for alternate lines of evidence implicating the particular variant in disease.

Membrane surface charge dictates the structure and function of the epithelial Na+/H+exchanger

The Na(+)/H(+) exchanger NHE3 plays a central role in intravascular volume and acid-base homeostasis. Ion exchange activity is conferred by its transmembrane domain, while regulation of the rate of transport by a variety of stimuli is dependent on its cytosolic C-terminal region. Liposome- and cell-based assays employing synthetic or recombinant segments of the cytosolic tail demonstrated preferential association with anionic membranes, which was abrogated by perturbations that interfere with electrostatic interactions. Resonance energy transfer measurements indicated that segments of the C-terminal domain approach the bilayer. In intact cells, neutralization of basic residues in the cytosolic tail by mutagenesis or disruption of electrostatic interactions inhibited Na(+)/H(+) exchange activity. An electrostatic switch model is proposed to account for multiple aspects of the regulation of NHE3 activity.

Intra-arterial Targeted Islet-specific Expression of Sirt1 Protects β Cells From Streptozotocin-induced Apoptosis in Mice

Gene therapy provides a promising approach to curing diabetes. However, an effective route for islet-specific targeting has yet to be established. Toward this end, the pancreatic blood circulation system in Balb/c mice was determined by the injection of rhodamine-containing beads. The efficiency of islet targeting was then measured by the injection of adenoviral vectors carrying a green fluorescence gene via the celiac trunk (C.T.). The results showed that >95% of islets and about 60% of β cells within the pancreatic body and tail could be labeled 3 days after surgery. α-Cell labeling was not as efficient, whereas labeling of nonendocrine tissues was barely detectable. For proof of principle, adenoviral vectors carrying a Sirtuin transgene were injected similarly to test the islet protection effect in the streptozotocin (STZ)-induced type 1 diabetic model. The results demonstrated that overexpression of Sirtuin in STZ-treated mice reduced the level of β-cell death and extent of glucose intolerance. This study reports on efficient islet-specific targeting by using adenoviral injection. This procedure could be invaluable to the treatment of diabetes and the study of islet biology.

A Computational Model for Cued Infant Learning

A Computational Model for Cued Infant Learning

S51 Thioredoxin modifies MIF release from human monocytes following stimulation with LTA and LPS

RationaleThioredoxin (Trx) is a 12-kDa ubiquitous redox-active thiol (-SH) protein. Plasma levels of Trx are raised in numerous medical and surgical conditions associated with oxidative stress and inflammation such as...

Metabolic regulation of Drosophila apoptosis through inhibitory phosphorylation of Dronc

Apoptosis ensures tissue homeostasis in response to developmental cues or cellular damage. Recently reported genome-wide RNAi screens have suggested that several metabolic regulators can modulate caspase activation in Drosophila. Here, we establish a previously unrecognized link between metabolism and Drosophila apoptosis by showing that cellular NADPH levels modulate the initiator caspase Dronc through its phosphorylation at S130. Depletion of NADPH removed this inhibitory phosphorylation, resulting in the activation of Dronc and subsequent cell death. Conversely, upregulation of NADPH prevented Dronc-mediated apoptosis upon DIAP1 RNAi or cycloheximide treatment. Furthermore, this CaMKII-mediated phosphorylation of Dronc hindered Dronc activation, but not its catalytic activity. Blockade of NADPH production aggravated the death-inducing activity of Dronc in specific neurons, but not in the photoreceptor cells of the eyes of transgenic flies; similarly, non-phosphorylatable Dronc was more potent than wild type in triggering specific neuronal apoptosis. Our observations reveal a novel regulatory circuitry in Drosophila apoptosis, and, as NADPH levels are elevated in cancer cells, also provide a genetic model to understand aberrations in cancer cell apoptosis resulting from metabolic alterations.

Orientation-specific control of attention

Many studies have shown that an irrelevant distractor matched to a target-defining color captures attention involuntarily, thus violating either temporal or spatial control of attention. However, whether an irrelevant orientation-matched distractor can capture attention is still unknown. We used a variant of a spatial blink task to examine whether an irrelevant distractor possessing the sought-for target orientation can capture attention. The general method is illustrated in figure 1. Participants were presented with a sequence of letters at fixation, each of which was contained within a gray bar and oriented at the same angle as the gray bar. One-half of the participants were asked to identify the sole target letter in the letter sequence oriented 45° clockwise from vertical. The other half of the participants searched for a letter oriented 45° counterclockwise from vertical. Six peripheral bars flanked the central letters either shortly before or after the appearance of the target letter. We found that six white vertical bars in the periphery did not impair target performance compared to no peripheral bars at all. However, a peripheral orientation singleton that matched the target orientation captured attention and severely impaired central target identification. More surprisingly, a peripheral orientation singleton that was perpendicular to the target orientation also captured attention and produced a similar impairment in performance as the orientation-matched distractor. And this effect was not due to stimulus-driven saliency of the orientation singleton because a horizontal singleton did not capture attention in this task. The results indicate that orientation-based modulation of attention is not as perfectly selective as color-based selection. Orientations that match the target or are perpendicular to it are both able to capture attention. Our results also are consistent with recent findings showing that a proportion of V2 and V3 neurons in monkeys have bimodal orientation tuning curves with two peaks 90° apart.

Corrigendum

CorrigendumCorrigendumPublished Online:01 Jul 2010https://doi.org/10.1152/physiolgenomics.zh7-3492-corr.2010Original articleMoreSectionsPDF (202 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Volume 41, March 2010Sanderson LM, Boekschoten MV, Desvergne B, Müller M, and Kersten S. Transcriptional profiling reveals divergent roles of PPARα and PPARβ/δ in regulation of gene expression in mouse liver. Physiol Genomics 41: , 2010. First published December 15, 2009; doi:10.1152/physiolgenomics.00127.2009; http://physiolgenomics.physiology.org/cgi/content/full/41/1/42.During production errors were introduced into Fig. 7. The y-axes in panel B should read “plasma βHBA (mM)”. In panel D, there are two asterisks over the righthand-most black bar where there should be only one. In panel E, an extra asterisk appears near the y-axis label for the righthand graph (over the word “glucose”). A corrected version of Fig. 7 appears below.Fig. 7.Similarities and differences in plasma and liver metabolic parameters between PPARα−/− and PPARβ/δ−/− mice. Plasma and liver metabolites were analyzed in fed and fasted wild type, PPARα−/−, and PPARβ/δ−/− mice. A: plasma free fatty acids; B: plasma β-hydroxybutyrate; C: plasma triglycerides; D: plasma cholesterol; E: plasma glucose; F: liver triglycerides; G: liver glycogen. White bars, fed state; black bars, fasted state; n = 5 per group. *Significantly different from corresponding wild-type mice according to student t-test (P < 0.05).Download figureDownload PowerPointThis article has no references to display. Download PDF Previous Back to Top FiguresReferencesRelatedInformationRelated ArticlesTranscriptional profiling reveals divergent roles of PPARα and PPARβ/δ in regulation of gene expression in mouse liver 01 Mar 2010Physiological Genomics More from this issue > Volume 42Issue 2July 2010Pages 317-317 Copyright & PermissionsCopyright © 2010 the American Physiological Societyhttps://doi.org/10.1152/physiolgenomics.zh7-3492-corr.2010History Published online 1 July 2010 Published in print 1 July 2010 Metrics

A Highly Toxic Cellular Prion Protein Induces a Novel, Nonapoptotic Form of Neuronal Death

Several different deletions within the N-terminal tail of the prion protein (PrP) induce massive neuronal death when expressed in transgenic mice. This toxicity is dose-dependently suppressed by coexpression of full-length PrP, suggesting that it results from subversion of a normal physiological activity of cellular PrP. We performed a combined biochemical and morphological analysis of Tg(DeltaCR) mice, which express PrP carrying a 21-aa deletion (residues 105-125) within a highly conserved region of the protein. Death of cerebellar granule neurons in Tg(DeltaCR) mice is not accompanied by activation of either caspase-3 or caspase-8 or by increased levels of the autophagy marker, LC3-II. In electron micrographs, degenerating granule neurons displayed a unique morphology characterized by heterogeneous condensation of the nuclear matrix without formation of discrete chromatin masses typical of neuronal apoptosis. Our data demonstrate that perturbations in PrP functional activity induce a novel, nonapoptotic, nonautophagic form of neuronal death whose morphological features are reminiscent of those associated with excitotoxic stress.

Ribosomal 18 S RNA Processing by the IGF-I-responsive WDR3 Protein Is Integrated with p53 Function in Cancer Cell Proliferation

Insulin-like growth factor-I (IGF-I) signaling is strongly associated with cell growth and regulates the rate of synthesis of the rRNA precursor, the first and the key stage of ribosome biogenesis. In a screen for mediators of IGF-I signaling in cancer, we recently identified several ribosome-related proteins, including NEP1 (nucleolar essential protein 1) and WDR3 (WD repeat 3), whose homologues in yeast function in ribosome processing. The WDR3 gene and its locus on chromosome 1p12-13 have previously been linked with malignancy. Here we show that IGF-I induces expression of WDR3 in transformed cells. WDR3 depletion causes defects in ribosome biogenesis by affecting 18 S rRNA processing and also causes a transient down-regulation of precursor rRNA levels with moderate repression of RNA polymerase I activity. Suppression of WDR3 in cells expressing functional p53 reduced proliferation and arrested cells in the G(1) phase of the cell cycle. This was associated with activation of p53 and sequestration of MDM2 by ribosomal protein L11. Cells lacking functional p53 did not undergo cell cycle arrest upon suppression of WDR3. Overall, the data indicate that WDR3 has an essential function in 40 S ribosomal subunit synthesis and in ribosomal stress signaling to p53-mediated regulation of cell cycle progression in cancer cells.

Deregulation of oncogene-induced senescence and p53 translational control in X-linked dyskeratosis congenita

Defects in ribosome biogenesis and function are present in a growing list of human syndromes associated with cancer susceptibility. One example is X-linked dyskeratosis congenita (X-DC) in which the DKC1 gene, encoding for an enzyme that modifies ribosomal RNA, is found to be mutated. How ribosome dysfunction leads to cancer remains poorly understood. A critical cellular response that counteracts cellular transformation is oncogene-induced senescence (OIS). Here, we show that during OIS, a switch between cap- and internal ribosome entry site (IRES)-dependent translation occurs. During this switch, an IRES element positioned in the 5'untranslated region of p53 is engaged and facilitates p53 translation. We further show that in DKC1(m) cells, p53 IRES-dependent translation is impaired during OIS ex vivo and on DNA damage in vivo. This defect in p53 translation perturbs the cellular response that counteracts oncogenic insult. We extend these findings to X-DC human patient cells in which similar impairments in p53 IRES-dependent translation are observed. Importantly, re-introduction of wild-type DKC1 restores p53 expression in these cells. These results provide insight into the basis for cancer susceptibility in human syndromes associated with ribosome dysfunction.

Lipid droplet analysis in caveolin-deficient adipocytes: alterations in surface phospholipid composition and maturation defects

Caveolins form plasmalemnal invaginated caveolae. They also locate around intracellular lipid droplets but their role in this location remains unclear. By studying primary adipocytes that highly express caveolin-1, we characterized the impact of caveolin-1 deficiency on lipid droplet proteome and lipidome. We identified several missing proteins on the lipid droplet surface of caveolin-deficient adipocytes and showed that the caveolin-1 lipid droplet pool is organized as multi-protein complexes containing cavin-1, with similar dynamics as those found in caveolae. On the lipid side, caveolin deficiency did not qualitatively alter neutral lipids in lipid droplet, but significantly reduced the relative abundance of surface phospholipid species: phosphatidylserine and lysophospholipids. Caveolin-deficient adipocytes can form only small lipid droplets, suggesting that the caveolin-lipid droplet pool might be involved in lipid droplet size regulation. Accordingly, we show that caveolin-1 concentration on adipocyte lipid droplets positively correlated with lipid droplet size in obese rodent models and human adipocytes. Moreover, rescue experiments by caveolin- green fluorescent protein in caveolin-deficient cells exposed to fatty acid overload demonstrated that caveolin-coated lipid droplets were able to grow larger than caveolin-devoid lipid droplets. Altogether, these data demonstrate that the lipid droplet-caveolin pool impacts on phospholipid and protein surface composition of lipid droplets and suggest a functional role on lipid droplet expandability.

RasGRP1 Is Essential for Ras Activation by the Tumor Promoter 12-O-Tetradecanoylphorbol-13-acetate in Epidermal Keratinocytes

RasGRP1 is a guanine nucleotide exchange factor for Ras that binds with high affinity to diacylglycerol analogs like the phorbol esters. Recently, we demonstrated a role for RasGRP1 in skin carcinogenesis and suggested its participation in the action of tumor-promoting phorbol esters like 12-O-tetradecanoylphorbol-13-acetate (TPA) on Ras pathways in epidermal cells. Given the importance of Ras in carcinogenesis, we sought to discern whether RasGRP1 was a critical pathway in Ras activation, using a RasGRP1 knockout (KO) mouse model to examine the response of keratinocytes to TPA. In contrast to the effect seen in wild type keratinocytes, Ras(GTP) levels were barely detected in RasGRP1 KO cells even after 60 min of exposure to phorbol esters. The lack of response was rescued by enforced expression of RasGRP1. Furthermore, small hairpin RNA-induced silencing of RasGRP1 abrogated the effect of TPA on Ras. Analysis of Ras isoforms showed that both H-Ras and N-Ras depended on RasGRP1 for activation by TPA, whereas activation of K-Ras could not be detected. Although RasGRP1 was dispensable for ERK activation in response to TPA, JNK activation was reduced in the KO keratinocytes. Notably, TPA-induced phosphorylation of JNK2, but not JNK1, was reduced by RasGRP1 depletion. These data identify RasGRP1 as a critical molecule in the activation of Ras by TPA in primary mouse keratinocytes and suggest JNK2 as one of the relevant downstream targets. Given the role of TPA as a skin tumor promoter, our findings provide additional support for a role for RasGRP1 in skin carcinogenesis.

Erratum to: Trans Fatty Acid‐Induced NF‐κB Activation Does Not Induce Insulin Resistance in Cultured Murine Skeletal Muscle Cells

In error, an incorrect version of Fig. 2a was published. They-axis of Fig. 2a was erroneously labeled, whereas the description in the text contained the correct data. The correct version of Fig. 2a is displayed below. These changes do not impact the interpretation of the data. NF-κB transcriptional activity and insulin sensitivity in skeletal muscle cells after incubation with geometric and positional C18:1 or C18:2 isomers. C2C12 myoblasts stably transfected with the 6κB-TK-luciferase construct were differentiated for 5 days and incubated with 400 μmol/l of the indicated FAs for 24 h (a). Lysates were prepared for assessment of luciferase activity. Values were corrected for protein content and expressed as fold-induction over control. Alternatively, 5 days differentiated L6-GLUT4myc myotubes were incubated with and without the indicated fatty acids (200 μmol/l, 16 h). Nuclear extracts were prepared and assessed for RelA DNA binding activity to a consensus NF-κB oligonucleotide by EMSA (b). Relative DNA binding activity was determined by phosphor-imager analysis and expressed as fold induction. Furthermore, 2-deoxyglucose uptake (c) and GLUT4 translocation (d) were measured after stimulation with 25 nmol/l insulin for 15 min in 5 days differentiated L6-GLUT4myc myotubes. Data are expressed as percentage of insulin-stimulated glucose uptake or GLUT4 translocation in absence of FA. Basal and insulin-stimulated conditions are represented by the white and black bars, respectively. *p < 0.05 versus control. #p < 0.05 versus insulin-stimulated control. Data shown are representative examples of three independent experiments