Tumor‑associated (TA) autoantibodies are considered to be promising biomarkers for the early detection of cancer, prior to the development of clinical symptoms. In the present study, a novel TA autoantibody was detected, which may prove to be useful as a diagnostic marker of human HCC using an HBx‑transgenic (HBx‑tg) hepatocellular carcinoma (HCC) mouse model. Its target antigen was identified as the bromodomain‑containing protein 2 (BRD2), a transcriptional regulator that plays a pivotal role in the transcriptional control of diverse genes.
View Article and Find Full Text PDFTranscription and replication of mitochondrial DNA (mtDNA) are regulated by nuclear DNA-encoded proteins that are targeted into mitochondria. A decrease in mtDNA copy number results in mitochondrial dysfunction, which may lead to insulin resistance and metabolic syndromes. We analyzed mitochondrial proteins that physically bind to human mitochondrial D-loop DNA using a shot-gun proteomics approach following protein enrichment by D-loop DNA-linked affinity chromatography.
View Article and Find Full Text PDFBackground: Atherosclerosis is one of the major complications of diabetes, which may result from insulin resistance via mitochondrial dysfunction. Although a strong association between insulin resistance and cardiovascular disease has been suggested, it is not clear yet whether stress-inducing factors damage mitochondria and insulin signaling pathway in cardiovascular tissues.
Methods: We investigated whether stress-induced mitochondrial dysfunction might alter the insulin/Akt signaling pathway in A10 rat vascular smooth muscle cells (VSMC).
Insulin signaling in the hypothalamus plays a role in maintaining body weight. Studies suggest that the forkhead transcription factor Foxo1 is an important mediator of insulin signaling in peripheral tissues. Here we demonstrate that in normal mice, hypothalamic Foxo1 expression is reduced by the anorexigenic hormones insulin and leptin.
View Article and Find Full Text PDFMitochondrial dysfunction may cause diabetes or insulin resistance. Peroxisome proliferation-activated receptor-gamma (PPAR-gamma) coactivator-1 alpha (PGC-1alpha) increases mitochondrial transcription factor A (Tfam) resulting in mitochondrial DNA content increase. An association between a single nucleotide polymorphism (SNP), G1444A(Gly482Ser), of PGC-1alpha coding region and insulin resistance has been reported in some ethnic groups.
View Article and Find Full Text PDFThe proximal region -234 to (+58 bp) of low-density lipoprotein receptor (LDLR) is responsible for its up-regulation by sterol regulatory element binding protein (SREBP). However, the mechanism of sterol-independent repression of LDLR has not been determined yet. In this study, we observed that there was an early induction and a later repression of LDLR by phorbol ester (PMA) in SK-Hep1 hepatocarcinoma cells and investigated the mechanisms through which PMA repressed LDLR transcription.
View Article and Find Full Text PDFMitochondrial dysfunction has been suggested as a causal factor for insulin resistance and diabetes. Previously we have shown a decrease of mitochondrial DNA (mtDNA) content in tissues of diabetic patients. The mitochondrial proteins, which regulate the mitochondrial biogensis, including transcription and replication of mtDNA, are encoded by nuclear DNA.
View Article and Find Full Text PDFMacrophage cells in response to cytokines and endotoxins produced a large amount of nitric oxide (NO) by expression of inducible nitric oxide synthase (iNOS), resulting in acute or chronic inflammatory disorders including septic hypotension and atherosclerosis. In the present study, we investigated the effect and the mechanism of mercaptopyrazine (MP) in the induction of iNOS and NO production as a culminating factor for several inflammatory disorders. Pretreatment of MP alleviated the mortality of endotoxemic mice receiving a lethal bolus of lipopolysaccharide (LPS), which was associated with the reduced levels of serum nitrite/nitrate and IL-1beta.
View Article and Find Full Text PDFAnn N Y Acad Sci
April 2004
Mitochondrial transcription factor A (Tfam, previously mtTFA) is a key regulator of mitochondrial DNA (mtDNA) transcription and replication. We have reported that overexpression of nuclear respiratory factor-1 (NRF-1) and high concentration (50 mM) of glucose increased the promoter activity of the rat Tfam in L6 rat skeletal muscle cells. In this study, we investigated the mechanism of high glucose-induced Tfam transactivation.
View Article and Find Full Text PDFDNA methylation on CpG dinucleotides inactivates the expression of the many genes. The decreased amount of mitochondrial DNA (mtDNA) has been suggested to be an important indicator of mitochondrial biogenesis and the pathogenesis of many human diseases. Since mitochondria transcription factor A (Tfam) is a key molecule to regulate mtDNA replication and its promoter contains many CpG dinucleotides, potential methylation sites, we investigated whether the site-specific methylation would modulate the Tfam promoter-driven transcriptional activity in vitro.
View Article and Find Full Text PDFMitochondrial transcription factor A (Tfam) is essential for the initiation of transcription and the replication of mitochondrial DNA (mtDNA). The 5'-upstream region of the rat Tfam gene was isolated from rat genomic DNA by extending the 5' sequence of newly identified Tfam cDNA using PCR-based Genome Walker. The identified rat Tfam gene showed little sequence homology with the upstream region of human Tfam.
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