Autocalibration based on dilution of a single concentrated standard is used for the determination of silicate in sea water by the modified molybdenum blue method

The silicate (Si) molybdenum blue method was modified by combining oxalate and ascorbic acid into a single reagent and was used for determining Si in sea water samples. The first step of this automated assay protocol was designed to perform either a calibration by a single Si standard prepared in deionized (DI) water, or to dilute samples in the range of 0-160 μM Si to fit into 0-20 μM Si calibration range using a 20 cm flow cell. By designing the assay protocol to function in batch mode, the influence of salinity on calibration was eliminated, thus making the method suitable for analysis of samples collected in the open ocean, coastal areas, or rivers. Reproducibility and accuracy of this method were evaluated by analysis of certified sea water reference materials. Phosphate (P) does not interfere significantly if the Si:P ratio is 4:1 or larger. The limit of detection was 514 nM Si, r.s.d. 2.1 %, sampling frequency 40 s/h, reagent consumption 700 μL/sample, and using deionized water as the carrier solution.

SOX4 reversibly induces phenotypic changes by suppressing the epithelial marker genes in human keratinocytes

BACKGROUND

SOX4 is a transcription factor belonging to the SOX (Sry-related High Mobility Group [HMG] box) family and plays a pivotal role in various biological processes at various stages of life. SOX4 is also expressed in the skin in adults and has been reported to be involved in wound healing, tumor formation, and metastasis.

METHODS AND RESULTS

In this study, we investigated the role of SOX4 in keratinocyte phenotypic changes. We generated a SOX4-overexpressing keratinocyte cell line that expresses SOX4 in a doxycycline (DOX)-inducible manner. DOX treatment induced a change from a paving stone-like morphology to a spindle-like morphology under microscopic observation. Comprehensive gene analysis by RNA sequencing revealed increased expression of genes related to anatomical morphogenesis and cell differentiation as well as decreased expression of genes related to epithelial formation and keratinization, suggesting that SOX4 induced EMT-like phenotype in keratinocytes. Differentially expressed genes (DEGs) obtained by RNA-seq were confirmed using qRT-PCR. DOX-treated TY-1 SOX4 showed a decrease in the epithelial markers (KRT15, KRT13, KRT5, and CLDN1) and an increase in the mesenchymal marker FN1. Protein expression changes by Western blotting also showed a decrease in the epithelial marker proteins keratin 15, keratin 13, and claudin 1, and an increase in the mesenchymal marker fibronectin. Removal of DOX from DOX-treated cells also restored the epithelial and mesenchymal markers altered by SOX4.

CONCLUSION

Our results indicate that SOX4 reversibly induces an EMT-like phenotype in human keratinocytes via suppression of epithelial marker genes.

SNAI2 is induced by transforming growth factor-β1, but is not essential for epithelial-mesenchymal transition in human keratinocyte HaCaT cells

Epithelial-mesenchymal transition (EMT) is a cellular process in which epithelial cells lose their epithelial traits and shift to the mesenchymal phenotype, and is associated with various biological events, such as embryogenesis, wound healing and cancer progression. The transcriptional program that promotes phenotype switching is dynamically controlled by transcription factors during EMT, including Snail (SNAI1), twist family bHLH transcription factor (TWIST) and zinc finger E-box binding homeobox 1 (ZEB1). The present study aimed to investigate the molecular mechanisms underlying EMT in squamous epithelial cells. Western blot analysis and immunocytochemical staining identified Slug (SNAI2) as a transcription factor that is induced during transforming growth factor (TGF)-β1-mediated EMT in the human keratinocyte cell line HaCaT. The effect of SNAI2 overexpression and knockdown on the phenotypic characteristics of HaCaT cells was evaluated. Filamentous actin staining and western blot analysis revealed that the overexpression of SNAI2 did not induce the observed EMT-related phenotypic changes. In addition, SNAI2 knockdown demonstrated almost no impact on the EMT phenotypes induced by TGF-β1. Notably, DNA microarray analysis followed by comprehensive bioinformatics analysis revealed that the differentially expressed genes upregulated by TGF-β1 were significantly enriched in cell adhesion and extracellular matrix binding, whereas the genes downregulated in response to TGF-β1 were significantly enriched in the cell cycle. No enriched gene ontology term and biological pathways were identified in the differentially expressed gene sets of SNAI2-overexpressing cells. In addition, the candidates for master transcription factors regulating the TGF-β1-induced EMT were identified using transcription factor enrichment analysis. In conclusion, the results of study demonstrated that SNAI2 does not play an essential role in the EMT of HaCaT cells and identified candidate transcription factors that may be involved in EMT-related gene expression induced by TGF-β1. These findings may enhance the understanding of molecular events in EMT and contribute to the development of a novel therapeutic approach against EMT in cancers and wound healing.

Analysis of existence of multidrug-resistant H58 gene in Salmonella enterica serovar Typhi isolated from typhoid fever patients in Makassar, Indonesia

The surveillance of multidrug-resistant (MDR) H58 typhoid is highly important, especially in endemic areas. MDR strain detection is needed by using a simple PCR technique that only uses a pair of primers. This is conducted considering the detection of Salmonella Typhi strains that have been carried out so far are only using antimicrobial sensitivity tests to determine microbial resistance phenotypically and to determine genotypically using complex molecular techniques. We aimed to analyse the existence of Salmonella Typhi MDR H58 in patients with typhoid fever in Makassar, Indonesia. A total of 367 blood samples of typhoid fever patients were collected from April 2018 until April 2019. The blood sample was cultured, then confirmed via simple PCR. All of the confirmed samples were tested for susceptibility against antibiotics and molecularly analysed for MDR H58 existence using a simple PCR technique. We found 7% (27/367) of the samples to be positive by both blood culture and PCR. All 27 isolates were found to be sensitive to sulfamethoxazole/trimethoprim. The lowest drug sensitivities were to amoxicillin, at one (3.7%) of 27 isolates, and ampicillin, at 13 (48.1%) of 27 isolates. Salmonella Typhi H58 PCR results showed that one (3.7%) of 27 isolates carried a positive fragment of 993 bp that led to the H58 strain, since the deletion flanks this fragment. The isolate was also found to be resistant to amoxicillin and fluoroquinolone according to a sensitivity test. Further molecular analysis needs to be conducted to examine the single isolate that carried the 933 bp fragment.

The effect of anti-tuberculosis drugs therapy on mRNA efflux pump gene expression of Rv1250 in Mycobacterium tuberculosis collected from tuberculosis patients

Efflux pumps are transmembrane proteins that vigorously participate in extruding a wide range of substrates, including drugs, outside the bacterial cell. We aimed to investigate the mRNA expression level of the Rv1250 efflux pump gene in Mycobacterium tuberculosis isolated from individuals with tuberculosis who received drug therapy, at the 1st, 3rd and 5th months, and newly diagnosed patients with tuberculosis who will receive drug therapy (0 month). The study was a multiple cross-sectional longitudinal design—50 different M. tuberculosis isolates and a reference strain H37Rv were subcultured in LJ medium and confirmed by multiplex PCR for identification of M. tuberculosis and collected for RNA extraction. Total bacterial mRNA was analysed using real-time quantitative PCR to evaluate mRNA quantification gene expression. There were differences in the level of Rv1250 mRNA expression between sensitive (n = 11) and resistant (n = 40) groups of 5.961 ± 0.414 and 10.192 ± 1.978, respectively (fold changes; p < 0.05). There were significant differences of expression level among M. tuberculosis-resistant groups (p < 0.05) specifically 7.573 ± 0.424 for 0-month drug therapy (n = 10), 9.438 ± 0.644 for 1st month drug therapy (n = 10), 11.057 ± 0.262 for 3rd month drug therapy (n = 10) and 12.701 ± 0.460 for 5th month drug therapy (n = 10). We assume that the extent of Rv1250 gene expression in M. tuberculosis clinical isolates is a result of the exposure to antimicrobials during treatment, which affect the basic expression of the efflux pump Rv1250 gene.

Online survey of genital and urinary symptoms among Japanese women aged between 40 and 90 years

OBJECTIVE

The purpose of this survey was to assess the prevalence of genital and urinary tract symptoms among Japanese women with declining estrogen levels.

METHODS

A health-related questionnaire survey was conducted among women in their 40s or older to inquire about their genital, intercourse-related, and urinary symptoms and concern over their symptoms.

RESULTS

Of the consecutive 10,000 respondents recruited, 4488 (44.9%) reported having symptoms: 3546 (79.0%) expressed concern over their symptoms. Furthermore, 2173 women (21.7%) had incontinence, 1999 (20.0%) had urinary frequency, 1648 (16.5%) had itching, and 1560 (15.6%) reported odor; these were followed by looseness, dryness, and burning. Of the 2518 (25.2%) sexually active women, 518 (20.6%) reported having dyspareunia and more reported having urinary symptoms than genital symptoms. Of the symptomatic respondents, 33.1% had genital symptoms alone, 28.4% had urinary symptoms alone, and 38.4% had both. More sexually active women had genital symptoms, while more sexually inactive women had urinary symptoms.

CONCLUSIONS

Genital and urinary symptoms were shown to be common and coexist in a considerable proportion of the respondents, highlighting the pathology of genitourinary syndrome of menopause. Again, dyspareunia and lower urinary tract symptoms were shown to be quite common among postmenopausal women.

PLXNA2 identified as a candidate gene by genome-wide association analysis for mandibular prognathism in human chondrocytes

In a previous genome-wide association study, plexin A2 (PLXNA2) was suggested as one of the candidate genes for mandibular prognathism. PLXNA2 encodes plexin A2, a member of the plexin-A family of semaphorin co-receptors. Semaphorin 3A (sema3A) exerts an osteoprotective effect. However, to the best of our knowledge, there have been no previous studies examining the role of sema3A or plexin A2 on human chondrocytes. The objectives of the present study were to examine the function of sema3A and its receptor, plexin A2, in human chondrocytes. Normal human chondrocytes were cultured in media with either a high (100 ng/ml) or a low (1 ng/ml) concentration of sema3A, or without sema3A as a control. Cells and extracellular matrices were assayed for concentrations of protein and parathyroid hormone-related peptide receptor 1 (PTH-R1) using a bicinchoninic acid assay and an enzyme immunoassay, respectively. At culture day 7, the high and low concentrations of exogenous sema3A significantly increased the protein content compared with the control (P=0.0008 and 0.00002, respectively). At culture day 14, a high concentration of exogenous sema3A significantly increased the protein content and decreased the concentration of PTH-R1 compared with the control (P=0.002). The present study revealed novel results that exogenous sema3A suppresses the expression of PTH-R1 in human proliferative chondrocytes and suggested that sema3A may affect human chondrocytes via its receptor, plexin A2.

Peptidylarginine deiminase is involved in maintaining the cornified oral mucosa of rats

BACKGROUND AND OBJECTIVE

Epithelial cells derived from different regions exhibit marked differences in their differentiation capacity, allowing them to provide a suitable protective barrier. We aimed to clarify the role of peptidylarginine deiminase (PAD) in modifying the key epidermal proteins filaggrin (FLG) and keratin 1 (K1) during stratification of the rat palate and buccal mucosa.

MATERIAL AND METHODS

We performed immunofluorescence, immunoblotting, PAD activity assays and 2-dimensional electrophoresis, and developed an organotypic culture model.

RESULTS

PAD1 expression was highest in the palate, whereas PAD2, PAD3 and PAD4 expression was highest in the skin, suggesting the tissue-specific expression of PAD isozymes that leads to differences in calcium dependency. Immunoblotting showed that the FLG monomer, as well as its degradation products and precursor (proFLG), were most abundantly expressed in the skin but had low expression in the palate, whereas only faint proFLG expression was detected in the buccal mucosa. FLG and K1 were colocalized with PAD1 and were likely to be citrullinated in the cornified layers of the skin; this colocalization was not detected on the palatal surface, and dot-like presence of proFLG that might be citrullinated and that of PAD1 were found in the granules of the palate. Organotypic models derived from the rat palate revealed that PAD inhibition reduced the breakdown of FLG, increased its association with K1 together with epithelial compaction, and decreased permeability in a dye permeability assay. Conversely, PAD stimulation had the opposite effects.

CONCLUSION

Citrullination is likely a protein modification that plays an important role in maintaining the structure and function of oral cornified mucosa in a way that is distinctly different from that of the skin.

TRPV2 channel inhibitors attenuate fibroblast differentiation and contraction mediated by keratinocyte-derived TGF-β1 in an in vitro wound healing model of rats

BACKGROUND

Keratinocytes release several factors that are involved in wound contracture and scar formation. We previously reported that a three-dimensional reconstruction model derived from rat skin represents a good wound healing model.

OBJECTIVE

We characterized the role of transient receptor potential (TRP) channels in the release of transforming growth factor (TGF)-β1 from keratinocytes and the differentiation of fibroblasts to identify possible promising pharmacological approaches to prevent scar formation and contractures.

METHODS

The three-dimensional culture model was made from rat keratinocytes seeded on a collagen gel in which dermal fibroblasts had been embedded.

RESULTS

Among the TRP channel inhibitors tested, the TRPV2 inhibitors SKF96365 and tranilast attenuated most potently keratinocyte-dependent and - independent collagen gel contraction due to TGF-β signaling as well as TGF-β1 release from keratinocytes and α-smooth muscle actin production in myofibroblasts. Besides the low amounts detected in normal dermis, TRPV2 mRNA and protein levels were increased after fibroblasts were embedded in the gel. TRPV2 was also expressed in the epidermis and keratinocyte layers of the model. Both inhibitors and TRPV2 siRNA attenuated the intracellular increase of Ca²⁺ induced by the TRPV agonist 2-aminoethoxydiphenyl borate in TGF-β1-pretreated fibroblasts.

CONCLUSION

This is the first study to show that compounds targeting TRPV2 channels ameliorate wound contraction through the inhibition of TGF-β1 release and the differentiation of dermal fibroblasts in a culture model.

Keratin 13 gene is epigenetically suppressed during transforming growth factor-β1-induced epithelial-mesenchymal transition in a human keratinocyte cell line

Epithelial-mesenchymal transition (EMT) is a biological event in which epithelial cells lose their polarity and cell-cell adhesions and concomitantly acquire mesenchymal traits, and is thought to play an important role in pathological processes such as wound healing and cancer progression. In this study, we evaluated transforming growth factor (TGF)-β1-treated human keratinocyte HaCaT cells as an in vitro model of EMT. HaCaT cells were changed into an elongated fibroblast-like morphology, which is indicative of EMT in response to TGF-β1. Phalloidin staining demonstrated the formation of actin stress fibers in TGF-β1-treated cells. Quantitative RT-PCR analysis revealed that TGF-β1 increased the mRNA levels of EMT transcription factors (SNAI2, TWIST1, and ZEB1) and mesenchymal markers (CDH2, VIM, and FN1), while it decreased the transcripts of epithelial phenotypic genes (CLDN1, OCLN, KRT5, KRT15, KRT13, and TGM1). Furthermore, we found that KRT13 was drastically suppressed through the reduction of RNA polymerase II occupancy of its promoter, which was accompanied by a decrease in active histone marks (H3K4me3 and H3K27ac) and an increase in a repressive mark (H3K27me3) during EMT. These findings indicate that the TGF-β1-induced EMT program regulates a subset of epithelial and mesenchymal marker genes, and that KRT13 is transcriptionally suppressed through the modulation of the chromatin state at the KRT13 promoter in HaCaT cells.

Loss of Interdependent Binding by the FoxO1 and FoxA1/A2 Forkhead Transcription Factors Culminates in Perturbation of Active Chromatin Marks and Binding of Transcriptional Regulators at Insulin-sensitive Genes

FoxO1 binds to insulin response elements located in the promoters of insulin-like growth factor-binding protein 1 (IGFBP1) and glucose-6-phosphatase (G6Pase), activating their expression. Insulin-mediated phosphorylation of FoxO1 promotes cytoplasmic translocation, inhibiting FoxO1-mediated transactivation. We have previously demonstrated that FoxO1 opens and remodels chromatin assembled from the IGFBP1 promoter via a highly conserved winged helix motif. This finding, which established FoxO1 as a "pioneer" factor, suggested a model whereby FoxO1 chromatin remodeling at regulatory targets facilitates binding and recruitment of additional regulatory factors. However, the impact of FoxO1 phosphorylation on its ability to bind chromatin and the effect of FoxO1 loss on recruitment of neighboring transcription factors at its regulatory targets in liver chromatin is unknown. In this study, we demonstrate that an amino acid substitution that mimics insulin-mediated phosphorylation of a serine in the winged helix DNA binding motif curtails FoxO1 nucleosome binding. We also demonstrate that shRNA-mediated loss of FoxO1 binding to the IGFBP1 and G6Pase promoters in HepG2 cells significantly reduces binding of RNA polymerase II and the pioneer factors FoxA1/A2. Knockdown of FoxA1 similarly reduced binding of RNA polymerase II and FoxO1. Reduction in acetylation of histone H3 Lys-27 accompanies loss of FoxO1 and FoxA1/A2 binding. Interdependent binding of FoxO1 and FoxA1/A2 possibly entails cooperative binding because FoxO1 and FoxA1/A2 facilitate one another's binding to IGFPB1 promoter DNA. These results illustrate how transcription factors can nucleate transcriptional events in chromatin in response to signaling events and suggest a model for regulation of hepatic glucose metabolism through interdependent FoxO/FoxA binding.

3-Deazaneplanocin A suppresses aggressive phenotype-related gene expression in an oral squamous cell carcinoma cell line

In tumor tissues, alterations of gene expression caused by aberrant epigenetic modifications confer phenotypic diversity on malignant cells. Although 3-deazaneplanocin A (DZNep) has been shown to reactivate tumor suppressor genes in several cancer cells, it remains unclear whether DZNep attenuates the malignant phenotypes of oral squamous cell carcinoma (OSCC) cells. In this study, we investigated the effect of DZNep on the expression of genes related to aggressive phenotypes, such as epithelial-mesenchymal transition, in OSCC cells. We found that DZNep reduced the cellular levels of polycomb group proteins (EZH2, SUZ12, BMI1, and RING1A) and the associated trimethylation of Lys27 on histone H3 and monoubiquitination of Lys119 on histone H2A in the poorly differentiated OSCC cell line SAS. Immunocytochemical staining demonstrated that DZNep induced the reorganization of filamentous actin and the membrane localization of E-cadherin associated with cell-cell adhesions. We also found an inhibitory effect of DZNep on cell proliferation using a WST assay. Finally, quantitative RT-PCR analysis demonstrated that genes involved in the aggressive phenotypes (TWIST2, EGFR, ACTA2, TGFB1, WNT5B, and APLIN) were down-regulated, whereas epithelial phenotype genes (CDH1, CLDN4, IVL, and TGM1) were up-regulated in SAS cells treated with DZNep. Collectively, our findings suggest that DZNep reverses the aggressive characteristics of OSCC cells through the dynamic regulation of epithelial plasticity via the reprogramming of gene expression patterns.

Integrin α6β4 and TRPV1 channel coordinately regulate directional keratinocyte migration

The directional migration of epithelial cells is crucial for wound healing. Among integrins, a family of cell adhesion receptors, integrin β4 has been assumed to be a promigratory factor, in addition to its role in stable adhesion. In turn, Ca(2+) signaling is also a key coordinator of migration. Keratinocytes reportedly express transient receptor potential vanilloid channels (TRPV1); however, the function of these channels as a regulator of intracellular Ca(2+) level in cell migration has remained uncharacterized. In the present study, we investigated the role of TRPV1 in directional migration related to integrin β4 using a scratch wound assay on a confluent monolayer sheet of murine keratinocytes (Pam212 cells). Double immunofluorescence staining revealed the de novo expression of integrin β4 and TRPV1 in migrating cells at the wound edge in response to scratch wounding, and both expression levels were almost matched. Epidermal growth factor (EGF) not only promoted keratinocyte migration, but also caused the further up-regulation of both integrin β4 and TRPV1. In addition, the knockdown of the integrin β4 or TRPV1 gene significantly impeded wound closure. The TRPV1 agonist capsaicin significantly promoted migration, while a selective TRPV1 antagonist inhibited it. The gene knockdown of TRPV1 inhibited the expression of the integrin β4 gene and that of β4 protein in migrating cells. These findings suggest that TRPV1 may stimulate directional migration directly by eliciting a Ca(2+) signal or indirectly via integrin β4 expression.

Epigenetic alterations of the keratin 13 gene in oral squamous cell carcinoma

Background

Epigenetic modifications play important roles in the regulation of gene expression determining cellular phenotype as well as various pathologies such as cancer. Although the loss of keratin 13 (KRT13) is reportedly linked to malignant transformation of oral epithelial cells, the molecular mechanisms through which KRT13 is repressed in oral squamous cell carcinoma (OSCC) remain unclear. The aim of this study is to identify the epigenetic alterations of the KRT13 gene in OSCCs.

Methods

We investigated KRT13 expression levels and chromatin modifications of the KRT13 promoter in the three OSCC cell lines (HSC4, HSC3, and SAS). The expression levels of KRT13 protein and mRNA were analyzed by western blotting and quantitative reverse-transcription polymerase chain reaction, respectively, and the localization of KRT13 protein was detected by immunofluorescence. DNA methylation and histone modifications in the KRT13 promoter were determined by bisulfite sequencing and chromatin immunoprecipitation (ChIP), respectively. For the pharmacological depletion of Polycomb repressive complex 2 (PRC2), cells were treated with 3-deazaneplanocin A (DZNep).

Results

KRT13 expression was transcriptionally silenced in the HSC3 and SAS cells and post-transcriptionally repressed in the HSC4 cells, while the KRT13 promoter was hypermethylated in all of the three OSCC cell lines. ChIP analysis revealed that PRC2-mediated trimethylation of Lys 27 on histone H3 (H3K27me3) was increased in the KRT13 promoter in the HSC3 and SAS cells. Finally, we demonstrated that the treatment of SAS cells with DZNep reactivated the transcription of KRT13 gene.

Conclusions

Our data provide mechanistic insights into the epigenetic silencing of KRT13 genes in OSCC cells and might be useful for the development of diagnostic markers and novel therapeutic approaches against OSCCs.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-988) contains supplementary material, which is available to authorized users.

Impact of psm-mec in the mobile genetic element on the clinical characteristics and outcome of SCCmec-II methicillin-resistant Staphylococcus aureus bacteraemia in Japan

Over-expression of alpha-phenol-soluble modulins (PSMs) results in high virulence of community-associated methicillin-resistant Staphylococcus aureus (MRSA). The psm-mec gene, located in the mobile genetic element SCCmec-II, suppresses PSMαs production. Fifty-two patients with MRSA bacteraemia were enrolled. MRSA isolates were evaluated with regard to the psm-mec gene sequence, bacterial virulence, and the minimum inhibitory concentration (MIC) of vancomycin and teicoplanin. Fifty-one MRSA isolates were classified as SCCmec-II, and 10 had one point mutation in the psm-mec promoter. We compared clinical characteristics and outcomes between mutant MRSA and wild-type MRSA. Production of PSMα3 in mutant MRSA was significantly increased, but biofilm formation was suppressed. Wild-type MRSA caused more catheter-related bloodstream infections (30/41 vs. 3/10, p 0.0028), whereas mutant MRSA formed more deep abscesses (4/10 vs. 3/41, p 0.035). Bacteraemia caused by mutant MRSA was associated with reduced 30-day mortality (1/10 vs. 13/41, p 0.25), although this difference was not significant. The MIC90 of teicoplanin was higher for wild-type MRSA (1.5 mg/L vs. 1 mg/L), but the MIC of vancomycin was not different between the two groups. The 30-day mortality of MRSA with a high MIC of teicoplanin (≥1.5 mg/L) was higher than that of strains with a lower MIC (≤0.75 mg/L) (6/10 vs. 6/33, p 0.017). Mutation of the psm-mec promoter contributes to virulence of SCCmec-II MRSA, and the product of psm-mec may determine the clinical characteristics of bacteraemia caused by SCCmec-II MRSA, but it does not affect mortality.

Proteolytic and non-proteolytic activation of keratinocyte-derived latent TGF-β1 induces fibroblast differentiation in a wound-healing model using rat skin

Transforming growth factor-β1 (TGF-β1) reportedly causes the differentiation of fibroblasts to myofibroblasts during wound healing. We investigated the mechanism underlying the activation of latent TGF-β1 released by keratinocytes in efforts to identify promising pharmacological approaches for the prevention of hypertrophic scar formation. A three-dimensional collagen gel matrix culture was prepared using rat keratinocytes and dermal fibroblasts. Stratified keratinocytes promoted the TGF receptor-dependent increase in α-smooth muscle actin (α-SMA) immunostaining and mRNA levels in fibroblasts. Latent TGF-β1 was found to be localized suprabasally and secreted. α-SMA expression was inhibited by an anti-αv-integrin antibody and a matrix metalloproteinase (MMP) inhibitor, GM6001. In a two-dimensional fibroblast culture, α-SMA expression depended on the production of endogenous TGF-β1 and required αv-integrin or MMP for the response to recombinant latent TGF-β1. In keratinocyte-conditioned medium, MMP-dependent latent TGF-β1 secretion was detected. Applying this medium to the fibroblast culture enhanced α-SMA production. This effect was decreased by GM6001, the anti-αv-integrin antibody, or the preabsorption of latent TGF-β1. These results indicate that keratinocytes secrete latent TGF-β1, which is liberated to fibroblasts over distance and is activated to produce α-SMA with the aid of a positive-feedback loop. MMP inhibition was effective for targeting both keratinocytes and fibroblasts in this model.

CLCA splicing isoform associated with adhesion through β1-integrin and its scaffolding protein: specific expression in undifferentiated epithelial cells

We previously found that a rat CLCA homologue (rCLCA-f) modulates Ca(2+)-dependent Cl(-) transport in the ductal cells of the rat submandibular gland. CLCA proteins have been shown to be multifunctional, with roles in, for example, cell adhesion. Here, we describe the mRNA and protein expressions of a splicing isoform of rat rCLCA (rCLCA-t). This isoform is a 514-amino acid protein containing a C-terminal 59-amino acid that is distinct from the rCLCA-f sequence. Immunohistochemistry revealed rCLCA-t to be located in the basal cells of the rat submandibular gland excretory duct and the stratum basale of rat epidermis, whereas rCLCA-f was detected in cells during the process of differentiation. In a heterologous expression system, rCLCA-t was found to be a membrane protein present predominantly in the perinuclear region, and not to be either present on the cell surface or secreted. rCLCA-t failed to enhance ionomycin-induced Cl(-) conductance (unlike rCLCA-f). When compared with rCLCA-f, it weakened cell attachment to a greater extent and in a manner that was evidently modulated by intracellular Ca(2+), protein kinase C, and β(1)-integrin. rCLCA-t was found to associate with RACK1 (receptor for activated C kinase) and to reduce expression of mature β(1)-integrin. Treatment of rat skin with rCLCA-t siRNA increased the expression of β(1)-integrin in the stratum basale of the epidermis. These results are consistent with cell-specific splicing of rCLCA mRNA playing a role in the modulation of the adhesive potential of undifferentiated epithelial cells.

Phylogenetic relationships in the coral family acroporidae, reassessed by inference from mitochondrial genes

Phylogenetic relationships within the dominant reef coral family Acroporidae were inferred from the mitochondrial genes cytochrome b and ATPase 6. The rate of nucleotide substitution in the genes gave proper resolution to deduce genetic relationships between the genera in this family. The molecular phylogeny divided this family into three major lineages: the genera Astreopora, Montipora and Acropora. The genus Anacropora was included in the same clade as the genus Montipora, suggesting its recent speciation from Montipora. The subgenus Isopora was significantly distant from the subgenus Acropora. Taken together with morphological and reproductive differences, we propose that these two subgenera be classified as independent genera. The divergence times deduced from the genetic distances were consistent with the fossil record for the major genera. The results also suggest that the extant reef corals speciated and expanded very recently, probably after the Miocene, from single lineage which survived repeated extinction by climate changes during the Cenozoic era.

Anks4b, a novel target of HNF4α protein, interacts with GRP78 protein and regulates endoplasmic reticulum stress-induced apoptosis in pancreatic β-cells

Mutations of the HNF4A gene cause a form of maturity-onset diabetes of the young (MODY1) that is characterized by impairment of pancreatic β-cell function. HNF4α is a transcription factor belonging to the nuclear receptor superfamily (NR2A1), but its target genes in pancreatic β-cells are largely unknown. Here, we report that ankyrin repeat and sterile α motif domain containing 4b (Anks4b) is a target of HNF4α in pancreatic β-cells. Expression of Anks4b was decreased in both βHNF4α KO islets and HNF4α knockdown MIN6 β-cells, and HNF4α activated Anks4b promoter activity. Anks4b bound to glucose-regulated protein 78 (GRP78), a major endoplasmic reticulum (ER) chaperone protein, and overexpression of Anks4b enhanced the ER stress response and ER stress-associated apoptosis of MIN6 cells. Conversely, suppression of Anks4b reduced β-cell susceptibility to ER stress-induced apoptosis. These results indicate that Anks4b is a HNF4α target gene that regulates ER stress in β-cells by interacting with GRP78, thus suggesting that HNF4α is involved in maintenance of the ER.

Voltage-gated K+ channel KCNQ1 regulates insulin secretion in MIN6 β-cell line

KCNQ1, located on 11p15.5, encodes a voltage-gated K(+) channel with six transmembrane regions, and loss-of-function mutations in the KCNQ1 gene cause hereditary long QT syndrome. Recent genetic studies have identified that single nucleotide polymorphisms located in intron 15 of the KCNQ1 gene are strongly associated with type 2 diabetes and impaired insulin secretion. In order to understand the role of KCNQ1 in insulin secretion, we introduced KCNQ1 into the MIN6 mouse β-cell line using a retrovirus-mediated gene transfer system. In KCNQ1 transferred MIN6 cells, both the density of the KCNQ1 current and the density of the total K(+) current were significantly increased. In addition, insulin secretion by glucose, pyruvate, or tolbutamide was significantly impaired by KCNQ1-overexpressing MIN6 cells. These results suggest that increased KCNQ1 protein expression limits insulin secretion from pancreatic β-cells by regulating the potassium channel current.

Acetylation curtails nucleosome binding, not stable nucleosome remodeling, by FoxO1

Transcriptional activity of FoxO factors is controlled through the actions of multiple growth factors signaling through protein kinase B, whereby phosphorylation of FoxO factors inhibits FoxO-mediated transactivation by promoting nuclear export. Phosphorylation of FoxO factors is enhanced by p300-mediated acetylation, which decreases their affinity for DNA. The negative effect of acetylation on FoxO DNA binding, together with nuclear FoxO mobility, is eliminated by over-expression of the de-acetylase Sirt1, suggesting that acetylation mobilizes FoxO factors in chromatin for inducible gene expression. Here, we show that acetylation significantly curtails the affinity of FoxO1 for its binding sites in nucleosomal DNA but has no effect on either stable nucleosome binding or remodeling by this factor. We suggest that, while acetylation provides a first, essential step toward mobilizing FoxO factors for inducible gene repression, additional mechanisms exist for overcoming their inherent capacity to stably bind and remodel nuclear chromatin.

Oral squamous cell carcinomas stimulate osteoclast differentiation

Matrix metalloproteinases (MMPs) play important roles in the invasion and metastasis to soft tissues of carcinomas including, oral squamous cell carcinomas (SCCs). Although, osteoclastic bone resorption is an important step in bone involvement in a variety of malignancies, the mechanism of bone involvement of oral SCC remains unclear. Once cancer cells arrest in bone, the bone is a storehouse of a variety of cytokines and growth factors and thus provides an extremely fertile environment for cell growth. The bone-invasive oral cancer cell line, BHY, transcriptionally expressed detectable levels of TGF-beta, IL-1beta, IL-8, parathyroid hormone-related protein (PTHrP) and vascular endothelial growth factor (VEGF) mRNAs and failed to express GM-CSF, IL-6, and TNF-alpha. Furthermore, the BHY-conditioned medium greatly upregulated IL-6 and RANKL/ODF mRNA expression in osteoblasts, suggesting a potential indirect stimulation of osteoclastogenesis via the osteogenic lineage. Seven out of eleven patients with carcinomas of the lower alveolus and gingiva showing infiltrative bone involvement expressed PTHrP mRNA. These data suggest that the occurrence of PTHrP may be an indication of developing oral malignant carcinomas.

Is there an increased risk of TB relapse in patients treated with fixed-dose combination drugs in Indonesia?

SETTING

South Sulawesi Province, Republic of Indonesia.

OBJECTIVE

To compare relapse rates among tuberculosis (TB) patients treated with fixed-dose combination drugs (FDCs) and patients treated with the same regimen using loose drugs.

METHODOLOGY

Between 1999 and 2001, new smear-positive TB patients were randomly allocated to treatment with four-drug FDCs or loose drugs to study differences in treatment outcomes. Although it was not in the original study design, in 2004-2005 we performed a follow-up study by home visit of cured patients. We conducted an interview and tried to collect a sputum sample from each patient. If the patient was absent or had died, a proxy interview was conducted. The sputum samples were examined by microscopy and culture.

RESULTS

The overall relapse rate was 7.0% in patients who were able to produce a sputum sample. Relapse appeared to be more frequent in the FDC group compared to the loose drug group (10.1% vs. 2.7%, P = 0.074).

CONCLUSION

This is the first documented long-term follow-up study of patients treated with four-drug FDCs. There is an indication that treatment of new sputum smear-positive TB patients with FDCs provides an increased risk of relapse compared to treatment with loose drugs. The long-term results of treatment with FDCs should be carefully evaluated in other settings.

Serum levels of interferon-gamma, tumour necrosis factor-alpha, soluble interleukin-6R and soluble cell activation markers for monitoring response to treatment of leprosy reactions

Identifying pathogen and host-related laboratory parameters are essential for the early diagnosis of leprosy reactions. The present study aimed to clarify the validity of measuring the profiles of serum cytokines [interleukin (IL)-4, IL-6, IL-10, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha], the soluble IL-6 receptor (sIL-6R), soluble T cell (sCD27) and macrophage (neopterin) activation markers and Mycobacterium leprae-specific anti-PGL-I IgM antibodies in relation to the leprosy spectrum and reactions. Serum samples from 131 Indonesian leprosy patients (82 non-reactional leprosy patients and 49 reactional) and 112 healthy controls (HC) from the same endemic region were investigated. Forty-four (89.8%) of the reactional patients had erythema nodosum leprosum (ENL) while only five (10.2%) had reversal reaction (RR). Follow-up serum samples after corticosteroid treatment were also obtained from 17 of the patients with ENL and one with RR. A wide variability in cytokine levels was observed in the patient groups. However, IFN-gamma and sIL-6R were elevated significantly in ENL compared to non-ENL patients. Levels of IFN-gamma, TNF-alpha and sIL-6R declined significantly upon corticosteroid treatment of ENL. Thus, although the present study suggests limited applicability of serial measurement of IFN-gamma, TNF-alpha and sIL-6R in monitoring treatment efficacy of ENL, reactions it recommends a search for a wider panel of more disease-specific markers in future studies.

An increased incidence of Enterobacter cloacae in a cardiovascular ward

Routine surveillance in a cardiovascular ward showed that the incidence of Enterobacter cloacae isolated from sputum and oropharyngeal cultures in June 2004 increased to 27.6% (8/29) compared to 5.5% (12/219) from the rest of the hospital during the same period (OR=13.2; 95% CI 2.97-58.7; P<0.05). While an increase in E. cloacae pneumonia was not verified, an investigation was undertaken by the infection control team to prevent an outbreak. The estimate of relative risk for E. cloacae infection was based on a case-control study which measured exposure to intubation, history of a stay in the intensive care unit (ICU) and oral care between patients with E. cloacae and those negative for E. cloacae. An odds ratio of 13.2 suggested cross-contamination via the transoesophageal echocardiography (TOE) probe in the ICU prior to transfer to the cardiovascular ward. Pulsed-field gel electrophoresis and antibiogram patterns were also consistent with this hypothesis. Intervention was undertaken in the form of enforcing the disinfection of TOE probes using a 0.55% phtharal solution and the use of a single-use sheath to protect the probe from recontamination. Following intervention, the incidence rate returned to previous levels. This report illustrates the limitations in the effectiveness of current nosocomial surveillance strategies due to the retrospective nature of analysis. Improved surveillance methods such as data-mining tools specifically applicable to the institution, patient population, region and country are needed to increase the sensitivity of detecting unrecognized outbreaks, including cross-contamination.

Adenovirus E1A negatively regulates E1AF, an ets family of the protein

E1AF was first identified as a transcription factor that binds to enhancer motifs of the adenovirus E1A gene and is thought to be a human homologue of mouse PEA3, one of the ets oncoprotein families. Here we show the effect of E1A on the gene expression and function of E1AF. E1A repressed the activity of E1AF promoter, and the N-terminal region of E1A, which is involved in the oncogenic activity of E1A, was essential for this repression. The ability as a transcription factor of E1AF, as well as those of the other PEA3 subfamily members ER81 and ERM, was also repressed by E1A via the same oncogenic domain. Furthermore, E1AF repressed the transformation activity of E1A cooperating with E1B, whereas the other ets family Ets-1 enhanced this activity. These results suggest that E1AF is one of the targets of E1A.

Molecular characterization of the zinc finger transcription factor, Osterix

Osterix was identified as a transcription factor expressing, in osteoblasts, required for bone formation. However, the molecular mechanisms of the gene regulation by Osterix remain elusive. In this study, we examined the transactivation property of Osterix by using the Gal4 fusion system reporter assay. We identified the transactivation domain of Osterix, which contains high proline and glycine residues and has an activation property in mammalian and yeast cells. The GST-pull down analysis revealed that the basal transcription factor, TF-IIB, but not TBP, binds to the transactivation domain. Furthermore, we found that Osterix interacts with chromatin remodeling factor, Brg-1, through its C-terminal zinc finger domain in vivo and in vitro. These findings suggest that Osterix possesses functional domains which associate with transcription mediated factors and functions as a transcriptional activator in the nucleus.

Does incineration turn infectious waste aseptic?

Incineration of infectious waste is considered to be biologically safe. We performed basic experiments to confirm that bacillus spores are killed by incineration in a muffle furnace. Biological samples containing 10(6) spores of Bacillus stearothermophilus were placed in stainless steel Petri dishes and then into hot furnaces. The furnace temperature and duration of incineration were 300 degrees C for 15 min, 300 degrees C for 30 min, 500 degrees C for 15 min, 500 degrees C for 30 min and 1100 degrees C for 3 min. We confirmed that all spores of B. stearothermophilus were killed at each of these settings. The effect of incineration seems to be equivalent to that of sterilization, based on the satisfactory sterilization assurance level of 10(-6).

Evaluation of a fully automated system (RAISUS) for rapid identification and antimicrobial susceptibility testing of Staphylococci

RAISUS is a system for rapid bacterial identification and antimicrobial susceptibility testing. RAISUS and VITEK showed 97.8% and 75.9% agreement in identification of 45 Staphylococcus aureus strains and 58 coagulase-negative staphylococci (CoNS), respectively, and RAISUS and CLSI (formerly NCCLS) methods showed 87.2% and 87.9% agreement in the MICs for S. aureus and CoNS, respectively. RAISUS provided these data within 3.75 h, suggesting its utility for clinical bacteriological laboratories.

Thypedin, the multi copy precursor for the hydra peptide pedin, is a β-thymosin repeat-like domain containing protein

Pedin, a peptide of 13 amino acids, stimulates foot formation in hydra, one of the simplest metazoan animals. Here, we show that the corresponding transcripts are 3.8 kb in size encoding a precursor protein with a size of about 110 kDa, which contains 13 copies of the peptide. Interestingly, the deduced amino acid sequence of the precursor comprises 27 copies of a beta-thymosin-like repeat domain. Hence, we named the precursor protein thypedin. Pedin transcripts are present along the body axis of the animal with slightly higher abundance in the foot to bud region and in the head. Pedin is expressed mainly in epithelial cells of the ectoderm and endoderm. During budding it is present in the evaginating bud. The early appearance of transcripts during phases of cell-fate specification like budding indicates that pedin may be involved in differentiation processes in hydra. This is confirmed by the fact that pedin stimulates bud outgrowth. Thymosin-repeat containing proteins are well known for their regulatory influence on actin polymerisation. Here we show the first indirect evidence that thypedin may be able to interact with actin as well. Since actin polymerisation and depolymerisation processes are known to take place during morphogenetic processes, these findings may hint at new aspects of the function of pedin and its precursor in pattern formation in hydra.

Acetylation of Foxo1 alters its DNA-binding ability and sensitivity to phosphorylation

The FOXO family of forkhead transcription factors plays a key role in a variety of biological processes, including metabolism, cell proliferation, and oxidative stress response. We previously reported that Foxo1, a member of the FOXO family, is regulated through reversible acetylation catalyzed by histone acetyltransferase cAMP-response element-binding protein (CREB)-binding protein (CBP) and NAD-dependent histone deacetylase silent information regulator 2, and that the acetylation at Lys-242, Lys-245, and Lys-262 of Foxo1 attenuates its transcriptional activity. However, the molecular mechanism by which acetylation modulates Foxo1 activity remains unknown. Here, we show that the positive charge of these lysines in Foxo1 contributes to its DNA-binding, and acetylation at these residues by CBP attenuates its ability to bind cognate DNA sequence. Remarkably, we also show that acetylation of Foxo1 increases the levels of its phosphorylation at Ser-253 through the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, and this effect was overridden on the acetylation-deficient Foxo1 mutant. Furthermore, in in vitro kinase reactions, the association of wild-type Foxo1 and its target DNA sequence inhibits the protein kinase B-dependent phosphorylation of Foxo1, whereas mutated Foxo1 proteins, which mimic constitutively acetylated states, are efficiently phosphorylated even in the presence of the DNA. These results suggest that acetylation regulates the function of Foxo1 through altering the affinity with the target DNA and the sensitivity for phosphorylation.

Inhalation of calcium channel blocking agents protects against methacholine-induced bronchoconstriction

The calcium channel blockers, diltiazem and verapamil, and the beta agonist orciprenaline sulfate all demonstrated significant protection against methacholine-induced bronchoconstriction in 11 stable asthmatics (5 males and 6 females). Ten and 20 mg of inhaled diltiazem, 5 mg of verapamil or 30 mg of orciprenaline administered 15 min before stepwise increasing doses of methacholine hydrochloride produced significant reduction in respiratory resistance (Rrs), minimum dose of methacholine hydrochloride required for Rrs increase (Dmin) and bronchial reactivity measured with an Astograph. The mechanism of action of the calcium channel blockers is presumably at the level of the smooth muscle cells themselves. The combination of positive influence and lack of any adverse effect on blood pressure or heart rate with any of the agents tested indicates that their clinical application for alleviation of acute asthma can be recommended.

Silent information regulator 2 potentiates Foxo1-mediated transcription through its deacetylase activity

Longevity regulatory genes include the Forkhead transcription factor FOXO and the NAD-dependent histone deacetylase silent information regulator 2 (Sir2). Genetic studies demonstrate that Sir2 acts to extend lifespan in Caenorhabditis elegans upstream of DAF-16, a member of the FOXO family, in the insulin-like signaling pathway. However, the molecular mechanisms underlying the requirement of DAF-16 activity in Sir2-mediated longevity remain unknown. Here we show that reversible acetylation of Foxo1 (also known as FKHR), the mouse DAF-16 ortholog, modulates its transactivation function. cAMP-response element-binding protein (CREB)-binding protein binds and acetylates Foxo1 at the K242, K245, and K262 residues, the modification of which is involved in the attenuation of Foxo1 as a transcription factor. Conversely, Sir2 binds and deacetylates Foxo1 at residues acetylated by cAMP-response element-binding protein-binding protein. Sir2 is recruited to insulin response sequence-containing promoter and increases the expression of manganese superoxide dismutase and p27(kip1) in a deacetylase-activity-dependent manner. Our findings establish Foxo1 as a direct and functional target for Sir2 in mammalian systems.

EWS/ETS fusions activate telomerase in Ewing's tumors

EWS/ETS is a chimeric protein identified in most Ewing's sarcomas. Although EWS/ETS has been shown to activate transcription as a transcription factor, the detailed targets of EWS/ETS in transformed cells have not been clarified. Herein, we demonstrate that telomerase is a new target of EWS/ETS fusions. Both telomerase activity and the expression level of telomerase reverse transcriptase (TERT) mRNA were up-regulated in NIH3T3 cells transformed by EWS/E1AF and EWS/FLI1 as well as in two Ewing's sarcoma cell lines. Luciferase assay using the TERT promoter revealed that EWS/E1AF and EWS/FLI1 function as positive regulators of TERT transcription in an ETS binding site-independent manner. EWS/ETS appeared to be included in the initiation complex of TERT transcription and to cooperate with CREB-binding protein (CBP)/p300. When EWS/FLI1 was knocked down in Ewing's sarcomas cells by RNA interference, the expression level of TERT mRNA and the telomerase activity were significantly decreased. These findings indicate that EWS/ETS fusion proteins activate human telomerase activity in Ewing's tumors through up-regulation of TERT gene expression, probably as a transcriptional coactivator.

Negative regulation of forkhead transcription factor AFX (Foxo4) by CBP-induced acetylation

AFX (also called Foxo4), a member of mammalian FOXO forkhead transcription factors, is the homolog of DAF-16, which contributes longevity and oxidative stress in Caenorhabditis elegans. Here, we show that CREB-binding protein (CBP) interacts with AFX via CH1 region and acetylates it at the three lysine residues (K186, K189, and K408). Trichostatin A (TSA) repressed the AFX-stimulated transcription, and substitution of the lysine residues with arginine (K186, 189, 408R) enhanced the transcriptional activity of AFX. Furthermore, TSA suppressed the expression of p27kip1 gene induced by AFX in HEK293T cells. Compared to the coexpression of CBP wild-type, a HAT activity-deficient mutant (DeltaHAT) efficiently leads the cooperative activation of AFX transcription in HepG2 cells. Taken together, these results demonstrate that CBP-induced acetylation of AFX is a novel modification mechanism by which AFX keeps the transcriptional activity mitigating in the nucleus.

Insulin-induced phosphorylation of FKHR (Foxo1) targets to proteasomal degradation

Forkhead transcription factor FKHR (Foxo1) is a key regulator of glucose homeostasis, cell-cycle progression, and apoptosis. It has been shown that FKHR is phosphorylated via insulin or growth factor signaling cascades, resulting in its cytoplasmic retention and the repression of target gene expression. Here, we investigate the fate of FKHR after cells are stimulated by insulin. We show that insulin treatment decreases endogenous FKHR proteins in HepG2 cells, which is inhibited by proteasome inhibitors. FKHR is ubiquitinated in vivo and in vitro, and insulin enhances the ubiquitination in the cells. In addition, the signal to FKHR degradation from insulin is mediated by the phosphatidylinositol 3-kinase pathway, and the mutation of FKHR at the serine or threonine residues phosphorylated by protein kinase B, a downstream target of phosphatidylinositol 3-kinase, inhibits the ubiquitination in vivo and in vitro. Finally, efficient ubiquitination of FKHR requires both phosphorylation and cytoplasmic retention in the cells. These results demonstrate that the insulin-induced phosphorylation of FKHR leads to the multistep negative regulation, not only by the nuclear exclusion but also the ubiquitination-mediated degradation.

Reverse Genetics for the Control of Avian Influenza

Avian influenza viruses are major contributors to viral disease in poultry as well as humans. Outbreaks of high-pathogenicity avian influenza viruses cause high mortality in poultry, resulting in significant economic losses. The potential of avian influenza viruses to reassort with human stains resulted in global pandemics in 1957 and 1968, while the introduction of an entirely avian virus into humans claimed several lives in Hong Kong in 1997. Despite considerable research, the mechanisms that determine the pathogenic potential of a virus or its ability to cross the species barrier are poorly understood. Reverse genetics methods, i.e., methods that allow the generation of an influenza virus entirely from cloned cDNAs, have provided us with one means to address these issues. In addition, reverse genetics is an excellent tool for vaccine production and development. This technology should increase our preparedness for future influenza virus outbreaks.

Regulation of PGC-1 promoter activity by protein kinase B and the forkhead transcription factor FKHR

Peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC-1) plays a major role in mediating hepatic gluconeogenesis in response to starvation, during which PGC-1 is induced by the cyclic AMP response element binding protein. Although it is observed that insulin counteracts PGC-1 transcription, the mechanism by which insulin suppresses the transcription of PGC-1 is still unclear. Here, we show that forkhead transcription factor FKHR contributes to mediating the effects of insulin on PGC-1 promoter activity. Reporter assays demonstrate that insulin suppresses the basal PGC-1 promoter activity and that coexpression of protein kinase (PK)-B mimics the effect of insulin in HepG2 cells. Insulin response sequences (IRSs) are addressed in the PGC-1 promoter as the direct target for FKHR in vivo. Coexpression of FKHR stimulates the PGC-1 promoter activity via interaction with the IRSs, while coexpression of FKHR (3A), in which the three putative PKB sites in FKHR are mutated, mainly abolishes the suppressive effect of PKB. Whereas deletion of the IRSs prevents the promoter stimulation by FKHR, that activity is still partially inhibited by insulin. These results indicate that signaling via PKB to FKHR can partly account for the effect of insulin to regulate the PGC-1 promoter activity via the IRSs.