FOXO1 and LXRα downregulate the apolipoprotein A-I gene expression during hydrogen peroxide-induced oxidative stress in HepG2 cells.

Reactive oxygen species damage various cell components including DNA, proteins, and lipids, and these impairments could be a reason for severe human diseases including atherosclerosis. Forkhead box O1 (FOXO1), an important metabolic transcription factor, upregulates antioxidant and proapoptotic genes during oxidative stress. Apolipoprotein A-I (ApoA-I) forms high density lipoprotein (HDL) particles that are responsible for cholesterol transfer from peripheral tissues to liver for removal in bile in vertebrates.

Insulin-Mediated Downregulation of Apolipoprotein A-I Gene in Human Hepatoma Cell Line HepG2: The Role of Interaction Between FOXO1 and LXRβ Transcription Factors.

Apolipoprotein A-I (ApoA-I) is a key component of high density lipoproteins which possess anti-atherosclerotic and anti-inflammatory properties. Insulin is a crucial mediator of the glucose and lipid metabolism that has been implicated in atherosclerotic and inflammatory processes. Important mediators of insulin signaling such as Liver X Receptors (LXRs) and Forkhead Box A2 (FOXA2) are known to regulate apoA-I expression in liver.

Peroxisome proliferator-activated receptor α positively regulates complement C3 expression but inhibits tumor necrosis factor α-mediated activation of C3 gene in mammalian hepatic-derived cells.

Complement C3 is a pivotal component of three cascades of complement activation. The liver is the main source of C3 in circulation and expression and secretion of C3 by hepatocytes is increased during acute inflammation. However, the mechanism of the regulation of the C3 gene in hepatocytes is not well elucidated.

Endogenous apolipoprotein A-I stabilizes ATP-binding cassette transporter A1 and modulates Toll-like receptor 4 signaling in human macrophages.

Apolipoprotein A-I (ApoA-I) is the main functional protein component of human high-density lipoproteins. ApoA-I shows various anti-inflammatory and atheroprotective properties toward macrophages; however, endogenous apoA-I expression has not been investigated in macrophages. We have shown that endogenous apoA-I gene is expressed in human macrophages at both mRNA and protein levels.

Modified low density lipoprotein stimulates complement C3 expression and secretion via liver X receptor and Toll-like receptor 4 activation in human macrophages.

Complement C3 is a pivotal component of three cascades of complement activation. C3 is expressed in human atherosclerotic lesions and is involved in atherogenesis. However, the mechanism of C3 accumulation in atherosclerotic lesions is not well elucidated.

PPARγ activates ABCA1 gene transcription but reduces the level of ABCA1 protein in HepG2 cells.

Synthesis of ABCA1 protein in liver is necessary for high-density lipoproteins (HDL) formation in mammals. Nuclear receptor PPARγ is known as activator of ABCA1 expression, but details of PPARγ-mediated regulation of ABCA1 at both transcriptional and post-transcriptional levels in hepatocytes have not still been well elucidated. In this study we have shown, that PPARγ activates ABCA1 gene transcription in human hepatoma cells HepG2 through increasing of LXRβ binding with promoter region of ABCA1 gene.

Effect of TNFalpha on activities of different promoters of human apolipoprotein A-I gene.

Human apolipoprotein A-I (ApoA-I) is a major structural and functional protein component of high-density lipoproteins. The expression of the apolipoprotein A-I gene (apoA-I) in hepatocytes is repressed by pro-inflammatory cytokines such as IL-1beta and TNFalpha. Recently, two novel additional (alternative) promoters for human apoA-I gene have been identified.

Novel repressor of the human FMR1 gene - identification of p56 human (GCC)(n)-binding protein as a Krüppel-like transcription factor ZF5.

A series of relatively short (GCC)(n) triplet repeats (n = 3-30) located within regulatory regions of many mammalian genes may be considered as putative cis-acting transcriptional elements (GCC-elements). Fragile X-mental retardation syndrome is caused by an expansion of (GCC)(n) triplet repeats within the 5'-untranslated region of the human fragile X-mental retardation 1 (FMR1) gene. The present study aimed to characterize a novel human (GCC)(n)-binding protein and investigate its possible role in the regulation of the FMR1 gene.

Complexes of plasmid DNA with basic domain 47-57 of the HIV-1 Tat protein are transferred to mammalian cells by endocytosis-mediated pathways.

Arginine-rich peptides, penetratins, as part of a number of cellular and viral proteins, can penetrate across plasma membrane directly, without participation of endocytosis. We show that one of penetratins, the basic domain 47-57 of human immunodeficiency virus, type 1, transcription factor Tat (Tat peptide), is able to interact with plasmid DNA electrostatically. These interactions result in formation of polyelectrolytic complexes at various negative/positive charge ratios of plasmid DNA and Tat peptide.