Regulation of NF-kappaB-dependent gene expression by the POU domain transcription factor Oct-1

Evaluation of Choroidal Thickness and Retinal Vessel Density with Serum HIF-1α and TNF-α Level in Patients with OSAS

PURPOSE

To reveal changes in choroidal thickness, retinal vessel density, and serum HIF-1α and TNF-α levels in obstructive sleep apnea syndrome (OSAS) and their correlation.

METHODS

This prospective case-control study included 118 patients divided into mild-to-moderate OSAS (n = 40), severe OSAS (n = 39), and a control group (n = 39). Choroidal thickness was evaluated with OCT, vessel density with OCTA, AHI index with polysomnography, and serum HIF-1α and TNF-α levels were analyzed using the enzyme-linked immunosorbent assay.

RESULTS

The serum HIF-1α values of the participants in the mild-moderate OSAS and severe OSAS groups were [893.25(406.7-2068) and 1027(453-2527), respectively], and were both significantly higher than the control group [(521.5(231.6-2741))] (p < 0.001). Serum TNF-α levels did not differ significantly between the groups (p = 0.051).). Subfoveal choroidal thickness (SFCT) values of the severe OSAS groups were significantly lower than the control group (p < 0.05). The superficial and deep capillary plexus vascular density (SVD and DVD) values of the severe OSAS group were lower than the control group (p < 0.05). Serum HIF-1α and TNF-α levels of all participants were negatively correlated with both their SVD values (p < 0.05, r: -0.220 and p < 0.05, r: -0.252, respectively) and their DVD values (p < 0.001, r: -0.324 and p = 0.001, r: -0.299, respectively).

CONCLUSIONS

Increased serum levels of inflammatory mediators (HIF-1α ve TNF-α) in OSAS cause a decrease in SFCT, SVD, and DVD, which is an indication of systemic vascular damage. Further research on developing treatment strategies to modulate TNF-α ve HIF-1α may help recede vascular morbidity in OSAS patients.

An updated review on cell signaling pathways regulated by candidate miRNAs in coronary artery disease

MicroRNAs (miRNAs) are small endogenous non-coding RNA, size range from 17 to 25 nucleotides that regulate gene expression at the post-transcriptional level. More than 2000 different types of miRNAs have been identified in humans which regulate about 60% of gene expression, since the discovery of the first miRNA in 1993. MicroRNA performs many functions such as being involved in the regulation of various biological pathways for example cell migration, cell proliferation, cell differentiation, disease progression, and initiation. miRNAs also play an important role in the development of atherosclerosis lesions, cardiac fibroblast, cardiac hypertrophy, cancer, and neurological disorders. Abnormal activation of many cell signaling pathways has been observed in the development of coronary artery disease. Abnormal expression of these candidate miRNA genes leads to up or downregulation of specific genes, these specific genes play an important role in the regulation of cell signaling pathways involved in coronary artery disease. Many studies have found that miRNAs play a key role in the regulation of crucial signaling pathways that are involved in the pathophysiology of coronary artery disease. This review is designed to investigate the role of cell signaling pathways regulated by candidate miRNAs in Coronary artery disease.

Potential roles of endothelial cells-related non-coding RNAs in cardiovascular diseases

Endothelial dysfunction is identified by a conversion of the endothelium toward decreased vasodilation and prothrombic features and is known as a primary pathogenic incident in cardiovascular diseases. An insight based on particular and promising biomarkers of endothelial dysfunction may possess vital clinical significances. Currently, non-coding RNAs due to their participation in critical cardiovascular processes like initiation and progression have gained much attention as possible diagnostic as well as prognostic biomarkers in cardiovascular diseases. Emerging line of proof has demonstrated that abnormal expression of non-coding RNAs is nearly correlated with the pathogenesis of cardiovascular diseases. In the present review, we focus on the expression and functional effects of various kinds of non-coding RNAs in cardiovascular diseases and negotiate their possible clinical implications as diagnostic or prognostic biomarkers and curative targets.

Combined effects of CXCL8 (IL-8) and CXCR2 (IL-8R) gene polymorphisms on deregressed MACE EBV indexes of milk-related traits in Simmental bulls

CXCL8 (also known as IL-8) is a member of the CXC subfamily of chemokines that binds two of the seven transmembrane G-protein-coupled receptors (GPCRs), CXCR1 and CXCR2, to mediate and regulate leucocyte accumulation and activation at sites of inflammation. They are known to play a critical role in both disease susceptibility and infection outcome. The aim of this study was to investigate the entire sequences of CXCL8 and CXCR2 genes in thirty-one Simmental sires to evaluate the effects of genomic variants on the indexes of the bulls for milk, fat and protein yields, and for somatic cell score (SCS). Five new single nucleotide polymorphisms (SNPs) were found in CXCR2 gene. The analysis of association indicated that one SNP in CXCL8 and two in CXCR2 influenced the considered traits. To evaluate the existence of functional haplotypic effects, combinations among the three genomic variants (SNP 1 in CXCL8, SNP 6 and SNP 7 in CXCR2) were investigated. Four different haplotypic alleles were identified in the experimental population, one of which at a high frequency (61%). Bulls with Hap 4 (G-C-G at SNP 1, SNP 6, and SNP 7 respectively) had more favourable indexes for SCS (P < 0.05). These results suggest that the SNPs in CXCL8 and CXCR2 may be potential genetic markers to improve udder health in the Simmental breed.

The Conserved Non-Coding Sequence 2 (CNS2) Enhances CD69 Transcription through Cooperation between the Transcription Factors Oct1 and RUNX1

The immune regulatory receptor CD69 is expressed upon activation in all types of leukocytes and is strongly regulated at the transcriptional level. We previously described that, in addition to the CD69 promoter, there are four conserved noncoding regions (CNS1-4) upstream of the CD69 promoter. Furthermore, we proposed that CNS2 is the main enhancer of CD69 transcription. In the present study, we mapped the transcription factor (TF) binding sites (TFBS) from ChIP-seq databases within CNS2. Through luciferase reporter assays, we defined a ~60 bp sequence that acts as the minimum enhancer core of mouse CNS2, which includes the Oct1 TFBS. This enhancer core establishes cooperative interactions with the 3′ and 5′ flanking regions, which contain RUNX1 BS. In agreement with the luciferase reporter data, the inhibition of RUNX1 and Oct1 TF expression by siRNA suggests that they synergistically enhance endogenous CD69 gene transcription. In summary, we describe an enhancer core containing RUNX1 and Oct1 BS that is important for the activity of the most potent CD69 gene transcription enhancer.

Alternative and canonical NF-kB pathways DNA-binding hierarchies networks define Hodgkin lymphoma and Non-Hodgkin diffuse large B Cell lymphoma respectively

PURPOSE

Despite considerable evidence that supports the NF-kB role in the immune system and lymphomagenesis, it is unclear whether specific NF-kB dimers control a particular set of genes that account for their biological functions. Our previous work showed that Hodgkin Lymphoma (HL) is unique, among germinal center (GC)-derived lymphomas, with respect to its dependency on Rel-B to survive. In contrast, diffuse large B-Cell lymphoma (DLBCL) including both Activated B-Cell-Like and Germinal Center B-Cell-Like, requires cREL and Rel-A to survive and it is not affected by Rel-B depletion. These findings highlighted the activity of specific NF-kB subunits in different GC-derived lymphomas.

METHODS

Sequenced chromatin immunoprecipitated DNA fragments (ChIP-Seq) analysis revealed an extensive NF-kB DNA-binding network in DLBCL and HL. The ChIP-Seq data was merged with microarray analysis following the Rel-A, Rel-B or cRel knockdown to determine effectively regulated genes.

RESULTS

Downstream target analysis showed enrichment for cell cycle control, among other signatures. Rel-B and cRel controlled different genes within the same signature in HL and DLBCL, respectively. BCL2 was exclusively controlled by Rel-B in HL. Both mRNA and protein levels decreased following Rel-B depletion meanwhile there was no change upon cRel knock-down. BCL2 exogenous expression partially rescued the death induced by decreased Rel-B in HL cells.

CONCLUSION

The Rel-B hierarchical network defined HL and the cRel hierarchical network characterized DLBCL. Each Rel member performs specific functions in distinct GC-derived lymphomas. This result should be considered for the development of targeted therapies that are aimed to selectively inhibit individual NF-kB dimers.

Abnormality of hepatic triglyceride metabolism in ApcMin/+ mice with colon cancer cachexia

AIMS

Colorectal cancer syndrome has been one of the greatest concerns in the world. Although several epidemiological studies have shown that hepatic low lipoprotein lipase (LPL) mRNA expression may be associated with dyslipidemia and tumor progression, it is still not known whether the liver plays an essential role in hyperlipidemia of Apc^Min/+ mice.

MAIN METHODS

We measured the expression of metabolic enzymes that involved fatty acid uptake, de novo lipogenesis (DNL), β-oxidation and investigated hepatic triglyceride production in the liver of wild-type and Apc^Min/+ mice.

KEY FINDINGS

We found that hepatic fatty acid uptake and DNL decreased, but there was no significant difference in fatty acid β-oxidation. Interestingly, the production of hepatic very low-density lipoprotein-triglyceride (VLDL-TG) decreased at 20 weeks of age, but marked steatosis was observed in the livers of the Apc^Min/+ mouse. To further explore hypertriglyceridemia, we assessed the function of hepatic glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 (GPIHBP1) for the first time. GPIHBP1 is governed by the transcription factor octamer-binding transcription factor-1 (Oct-1) which are involved in the nuclear factor-κB (NF-κB) signaling pathway in the liver of Apc^Min/+ mice. Importantly, it was also confirmed that sn50 (100 μg/mL, an inhibitor of the NF-κB) reversed the tumor necrosis factor α (TNFα)-induced Oct-1 and GPIHBP1 reduction in HepG2 cells.

SIGNIFICANCE

Altogether, these findings highlighted a novel role of GPIHBP1 that might be responsible for hypertriglyceridemia in Apc^Min/+ mice. Hypertriglyceridemia in these mice may be associated with their hepatic lipid metabolism development.

Nubbin isoform antagonism governs Drosophila intestinal immune homeostasis

Gut immunity is regulated by intricate and dynamic mechanisms to ensure homeostasis despite a constantly changing microbial environment. Several regulatory factors have been described to participate in feedback responses to prevent aberrant immune activity. Little is, however, known about how transcriptional programs are directly tuned to efficiently adapt host gut tissues to the current microbiome. Here we show that the POU/Oct gene nubbin (nub) encodes two transcription factor isoforms, Nub-PB and Nub-PD, which antagonistically regulate immune gene expression in Drosophila. Global transcriptional profiling of adult flies overexpressing Nub-PB in immunocompetent tissues revealed that this form is a strong transcriptional activator of a large set of immune genes. Further genetic analyses showed that Nub-PB is sufficient to drive expression both independently and in conjunction with nuclear factor kappa B (NF-κB), JNK and JAK/STAT pathways. Similar overexpression of Nub-PD did, conversely, repress expression of the same targets. Strikingly, isoform co-overexpression normalized immune gene transcription, suggesting antagonistic activities. RNAi-mediated knockdown of individual nub transcripts in enterocytes confirmed antagonistic regulation by the two isoforms and that both are necessary for normal immune gene transcription in the midgut. Furthermore, enterocyte-specific Nub-PB expression levels had a strong impact on gut bacterial load as well as host lifespan. Overexpression of Nub-PB enhanced bacterial clearance of ingested Erwinia carotovora carotovora 15. Nevertheless, flies quickly succumbed to the infection, suggesting a deleterious immune response. In line with this, prolonged overexpression promoted a proinflammatory signature in the gut with induction of JNK and JAK/STAT pathways, increased apoptosis and stem cell proliferation. These findings highlight a novel regulatory mechanism of host-microbe interactions mediated by antagonistic transcription factor isoforms.

Different N-terminal isoforms of Oct-1 control expression of distinct sets of genes and their high levels in Namalwa Burkitt's lymphoma cells affect a wide range of cellular processes

Oct-1 transcription factor has various functions in gene regulation. Its expression level is increased in several types of cancer and is associated with poor survival prognosis. Here we identified distinct Oct-1 protein isoforms in human cells and compared gene expression patterns and functions for Oct-1A, Oct-1L, and Oct-1X isoforms that differ by their N-terminal sequences. The longest isoform, Oct-1A, is abundantly expressed and is the main Oct-1 isoform in most of human tissues. The Oct-1L and the weakly expressed Oct-1X regulate the majority of Oct-1A targets as well as additional sets of genes. Oct-1X controls genes involved in DNA replication, DNA repair, RNA processing, and cellular response to stress. The high level of Oct-1 isoforms upregulates genes related to cell cycle progression and activates proliferation both in Namalwa Burkitt's lymphoma cells and primary human fibroblasts. It downregulates expression of genes related to antigen processing and presentation, cytokine-cytokine receptor interaction, oxidative metabolism, and cell adhesion, thus facilitating pro-oncogenic processes.

From DNA damage to functional changes of the trabecular meshwork in aging and glaucoma

Glaucoma is a degenerative disease of the eye. Both the anterior and posterior segments of the eye are affected, extensive damage being detectable in the trabecular meshwork and the inner retina-central visual pathway complex. Oxidative stress is claimed to be mainly responsible for molecular damage in the anterior chamber. Indeed, oxidation harms the trabecular meshwork, leading eventually to endothelial cell decay, tissue malfunction, subclinical inflammation, changes in the extracellular matrix and cytoskeleton, altered motility, reduced outflow facility and (ultimately) increased IOP. Moreover, free radicals are involved in aging and can be produced in the brain (as well as in the eye) as a result of ischemia, leading to oxidation of the surrounding neurons. Glaucoma-related cell death occurs by means of apoptosis, and apoptosis is triggered by oxidative stress via (a) mitochondrial damage, (b) inflammation, (c) endothelial dysregulation and dysfunction, and (d) hypoxia. The proteomics of the aqueous humor is significantly altered in glaucoma as a result of oxidation-induced trabecular damage. Those proteins whose aqueous humor levels are increased in glaucoma are biomarkers of trabecular meshwork impairment. Their diffusion from the anterior to the posterior segment of the eye may be relevant in the cascade of events triggering apoptosis in the inner retinal layers, including the ganglion cells.

Oct-1, to go or not to go? That is the PolII question

The Oct transcription factors recognise an octamer DNA element from which they regulate transcription of specific target genes. Oct-1 is the only member of the subfamily that is ubiquitously expressed and has a wide role in transcriptional control. Through interaction with various partner proteins, Oct-1 can modulate accessibility to the chromatin to recruit the transcription machinery and form the pre-initiation complex. The recruited PolII is induced to initiate transcription and stalled until elongation is triggered on interaction with signalling transcription factors. In this way, Oct-1 can fulfil general roles in transcription by opening the chromatin as well as transduce extracellular signals by relaying activation through various interacting partners. The emerging picture of Oct-1 is that of a complex and versatile transcription factor with fundamental functions in cell homeostasis and signal response in general as well as cell specific contexts. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin.

Regulatory roles of Oct proteins in the mammary gland

The expression of Oct-1 and -2 and their binding to the octamer motif in the mammary gland are developmentally and hormonally regulated, consistent with the expression of milk proteins. Both of these transcription factors constitutively bind to the proximal promoter of the milk protein gene β-casein and might be involved in the inhibition or activation of promoter activity via interactions with other transcription factors or cofactors at different developmental stages. In particular, the lactogenic hormone prolactin and glucocorticoids induce Oct-1 and Oct-2 binding and interaction with both the signal transducer and activator of transcription 5 (STAT5) and the glucocorticoid receptor on the β-casein promoter to activate β-casein expression. In addition, increasing evidence has shown the involvement of another Oct factor, Oct-3/4, in mammary tumorigenesis, making Oct-3/4 an emerging prognostic marker of breast cancer and a molecular target for the gene-directed therapeutic intervention, prevention and treatment of breast cancer. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin.

Transcription Factors Oct-1 and GATA-3 Cooperatively Regulate Th2 Cytokine Gene Expression via the RHS5 within the Th2 Locus Control Region

The T helper type 2 (Th2) locus control region (LCR) regulates Th2 cell differentiation. Several transcription factors bind to the LCR to modulate the expression of Th2 cytokine genes, but the molecular mechanisms behind Th2 cytokine gene regulation are incompletely understood. Here, we used database analysis and an oligonucleotide competition/electrophoretic mobility shift assays to search for transcription factors binding to RHS5, a DNase I hypersensitive site (DHS) within the Th2 LCR. Consequently, we demonstrated that GATA-binding protein-3 (GATA-3), E26 transformation-specific protein 1 (Ets-1), octamer transcription factor-1 (Oct-1), and Oct-2 selectively associate with RHS5. Furthermore, chromatin immunoprecipitation and luciferase reporter assays showed that Oct-1 and Oct-2 bound within the Il4 promoter region and the Th2 LCR, and that Oct-1 and GATA-3 or Oct-2 synergistically triggered the transactivational activity of the Il4 promoter through RHS5. These results suggest that Oct-1 and GATA-3/Oct-2 direct Th2 cytokine gene expression in a cooperative manner.

The role of miR-19b in the inhibition of endothelial cell apoptosis and its relationship with coronary artery disease

The biological effects of microRNAs (miRNAs) and TNF-α in atherosclerosis have been widely studied. The circulating miR-17-92 cluster has been recently shown to be significantly downregulated in patients with injured vascular endothelium. However, it remains unclear whether the miR-17-92 cluster plays a significant role in vascular endothelial repair. The aim of this study was to investigate the relationship between the miR-17-92 cluster and TNF-α-induced endothelial cell apoptosis. We determined that the down-regulation of miR-19b level among patients with coronary artery disease was consistent with miRNA expression changes in endothelial cells following 24 h of TNF-α treatment. In vitro, the overexpression of miR-19b significantly alleviated the endothelial cells apoptosis, whereas the inhibition of miR-19b significantly enhanced apoptosis. The increased levels of Afap1 and caspase7 observed in our apoptosis model could be reduced by miR-19b, and this effect could be due to miR-19b binding 3'-UTRs of Afap1 and caspase7 mRNA. Therefore our results indicate that miR-19b plays a key role in the attenuation of TNF-α-induced endothelial cell apoptosis and that this function is closely linked to the Apaf1/caspase-dependent pathway.

Tumor necrosis factor-α inhibitors as a treatment of corneal hemangiogenesis and lymphangiogenesis

The cornea is normally devoid of blood and lymphatic vessels; however, a number of infectious/inflammatory diseases can induce corneal neovascularization (CNV). Tumor necrosis factor (TNF)-α, a well known pro-inflammatory cytokine, acts on the vascular endothelium by promoting vasodilatation, edema, and leukocyte recruitment, which are all commonly associated with the development of CNV. Corneal neovascularization is the second cause of blindness worldwide; hence, pharmacological TNF-α inhibition might represent an attractive therapeutic option. Although none of the existing TNF-α antagonists has been registered as a CNV inhibitor, three of them (etanercept, adalimumab, and infliximab) have been proposed to control ocular inflammation. More specifically, it has been demonstrated that infliximab is also effective in reducing hemangiogenesis and lymphangiogenesis in different animal models of CNV. In this article, we review the role of TNF-α on the ocular surface and, in particular, its specific role in the process of CNV. Moreover, we review existing literature and speculate on the potential role of TNF-α inhibitors in the treatment of CNV.

Genomic characterization and expression analysis of five novel IL-17 genes in the Pacific oyster, Crassostrea gigas

Interleukin-17 (IL-17) is a proinflammatory cytokine that plays an important role in clearing extracellular bacteria and contributes to the pathology of many autoimmune and allergic conditions. In the present study, five novel IL-17 homologs were identified by searching and analyzing the Pacific oyster genome. All six CgIL-17 members (including a previously reported homolog) contained four conserved cysteines that were used in the formation of disulfide bonds. Phylogenetic analysis showed that all invertebrate IL-17s were clustered into one group, implying that invertebrate IL-17s evolved from one common ancestral gene and subsequently diversified. All CgIL-17s shared the same genomic structure, containing two exons and one intron, except for the CgIL-17-3 and CgIL-17-5 genes, which each had only one exon. The expression pattern of the CgIL-17 genes was analyzed by qRT-PCR in a variety of tissues and at different developmental stages, and these genes were highly expressed in the gill and digestive gland tissues. Moreover, the expression of the CgIL-17 family genes was significantly up-regulated in hemocytes challenged with Pathogen-Associated Molecular Patterns (PAMPs). CgIL-17-3 had a strong response to lipopolysaccharide (LPS) and heat-killed Vibrio alginolyticus (HKVA) challenge, while CgIL-17-5 and CgIL-17-6 can be activated by peptidoglycan (PGN), but not by heat-killed Listeria monocytogenes (HKLM). The distinct, up-regulated transcript levels of the CgIL-17s in response to PAMPs challenge further indicate that CgIL-17s are likely to be significant components of immune responses by playing diversified roles in host defense in the Pacific oyster. These findings suggest that CgIL-17s are involved in innate immune responses and further supports their conserved function in mollusks immunity.

Focus on molecular events in the anterior chamber leading to glaucoma

Primary open-angle glaucoma is a multifactorial disease that affects the retinal ganglion cells, but currently its therapy is to lower the eye pressure. This indicates a definite involvement of the trabecular meshwork, key region in the pathogenesis of glaucoma. This is the first target of glaucoma, and its functional complexity is a real challenge to search. Its functions are those to allow the outflow of aqueous humor and not the reflux. This article describes the morphological and functional changes that happen in anterior chamber. The "primus movens" is oxidative stress that affects trabecular meshwork, particularly its endothelial cells. In these develops a real mitochondriopaty. This leads to functional impotence, the trabecular meshwork altering both motility and cytoarchitecture. Its cells die by apoptosis, losing barrier functions and altering the aqueous humor outflow. All the morphological alterations occur that can be observed under a microscope. Intraocular pressure rises and the malfunctioning trabecular meshwork endotelial cells express proteins that completely alter the aqueous humor. This is a liquid whose functional proteomics complies with the conditions of the trabecular meshwork. Indeed, in glaucoma, it is possible detect the presence of proteins which testify to what occurs in the anterior chamber. There are six classes of proteins which confirm the vascular endothelium nature of the anterior chamber and are the result of the morphofunctional trabecular meshwork decay. It is possible that, all or in part, these proteins can be used as a signal to the posterior pole.

Oct-1 regulates IL-17 expression by directing interchromosomal associations in conjunction with CTCF in T cells

Interchromosomal associations can regulate gene expression, but little is known about the molecular basis of such associations. In response to antigen stimulation, naive T cells can differentiate into Th1, Th2, and Th17 cells expressing IFN-γ, IL-4, and IL-17, respectively. We previously reported that in naive T cells, the IFN-γ locus is associated with the Th2 cytokine locus. Here we show that the Th2 locus additionally associates with the IL-17 locus. This association requires a DNase I hypersensitive region (RHS6) at the Th2 locus. RHS6 and the IL-17 promoter both bear Oct-1 binding sites. Deletion of either of these sites or Oct-1 gene impairs the association. Oct-1 and CTCF bind their cognate sites cooperatively, and CTCF deficiency similarly impairs the association. Finally, defects in the association lead to enhanced IL-17 induction. Collectively, our data indicate Th17 lineage differentiation is restrained by the Th2 locus via interchromosomal associations organized by Oct-1 and CTCF.

The Oct1 homolog Nubbin is a repressor of NF-κB-dependent immune gene expression that increases the tolerance to gut microbiota

Background

Innate immune responses are evolutionarily conserved processes that provide crucial protection against invading organisms. Gene activation by potent NF-κB transcription factors is essential both in mammals and Drosophila during infection and stress challenges. If not strictly controlled, this potent defense system can activate autoimmune and inflammatory stress reactions, with deleterious consequences for the organism. Negative regulation to prevent gene activation in healthy organisms, in the presence of the commensal gut flora, is however not well understood.

Results

We show that the Drosophila homolog of mammalian Oct1/POU2F1 transcription factor, called Nubbin (Nub), is a repressor of NF-κB/Relish-driven antimicrobial peptide gene expression in flies. In nub¹ mutants, which lack Nub-PD protein, excessive expression of antimicrobial peptide genes occurs in the absence of infection, leading to a significant reduction of the numbers of cultivatable gut commensal bacteria. This aberrant immune gene expression was effectively blocked by expression of Nub from a transgene. We have identified an upstream regulatory region, containing a cluster of octamer sites, which is required for repression of antimicrobial peptide gene expression in healthy flies. Chromatin immunoprecipitation experiments demonstrated that Nub binds to octamer-containing promoter fragments of several immune genes. Gene expression profiling revealed that Drosophila Nub negatively regulates many genes that are involved in immune and stress responses, while it is a positive regulator of genes involved in differentiation and metabolism.

Conclusions

This study demonstrates that a large number of genes that are activated by NF-κB/Relish in response to infection are normally repressed by the evolutionarily conserved Oct/POU transcription factor Nub. This prevents uncontrolled gene activation and supports the existence of a normal gut flora. We suggest that Nub protein plays an ancient role, shared with mammalian Oct/POU transcription factors, to moderate responses to immune challenge, thereby increasing the tolerance to biotic stress.

Statins protect human endothelial cells from TNF-induced inflammation via ERK5 activation

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) exert pleiotropic effects on the cardiovascular system, in part through a decrease in reactive oxygen species (ROS) formation and reduction of vascular inflammation. To elucidate the molecular mechanisms involved in these effects, we investigated the effect of statins on TNF-α-induced ROS production, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) expression in human aortic endothelial cells (HAECs). Exposure of HAECs to TNF-α caused production of ROS via Rac-1 membrane translocation and activation. The Rac-1 activation and ROS liberation mediated TNF-stimulated NF-κB activation and the subsequent VCAM-1 and ICAM-1 expression. Extracellular-signal-regulated kinase 5 (ERK5) plays a central role in inhibiting endothelial inflammation. Immune complex kinase assay of protein extracts from HAECs treated with atorvastatin revealed increased ERK5 activity in a time- and dose-dependent manner. In addition, pretreatment with atorvastatin inhibited TNF-α-induced ROS production and VCAM-1 and ICAM-1 expression. Chemical or genetic inhibition of ERK5 ablated the statins inhibition of Rac-1 activation, ROS formation, NF-κB, VCAM-1 and ICAM-1 expression induced by TNF-α. Taken together, statins, via ERK5 activation, suppress TNF-stimulated Rac-1 activation, ROS generation, NF-κB activation and VCAM-1 and ICAM-1 expression in human ECs, which provides a novel explanation for the pleiotropic effects of statins that benefit the cardiovascular system.

Oct-1 acts as a transcriptional repressor on the C-reactive protein promoter

C-reactive protein (CRP), a plasma protein of the innate immune system, is produced by hepatocytes. A critical regulatory region (-42 to -57) on the CRP promoter contains binding site for the IL-6-activated transcription factor C/EBPβ. The IL-1β-activated transcription factor NF-κB binds to a κB site located nearby (-63 to -74). The κB site overlaps an octamer motif (-59 to -66) which is the binding site for the constitutively active transcription factor Oct-1. Oct-1 is known to function both as a transcriptional repressor and as an activator depending upon the promoter context. Also, Oct-1 can regulate gene expression either by binding directly to the promoter or by interacting with other transcription factors bound to the promoter. The aim of this study was to investigate the functions of Oct-1 in regulating CRP expression. In luciferase transactivation assays, overexpressed Oct-1 inhibited (IL-6+IL-1β)-induced CRP expression in Hep3B cells. Deletion of the Oct-1 site from the promoter drastically reduced the cytokine response because the κB site was altered as a consequence of deleting the Oct-1 site. Surprisingly, overexpressed Oct-1 inhibited the residual (IL-6+IL-1β)-induced CRP expression through the promoter lacking the Oct-1 site. Similarly, deletion of the Oct-1 site reduced the induction of CRP expression in response to overexpressed C/EBPβ, and overexpressed Oct-1 inhibited C/EBPβ-induced CRP expression through the promoter lacking the Oct-1 site. We conclude that Oct-1 acts as a transcriptional repressor of CRP expression and it does so by occupying its cognate site on the promoter and also via other transcription factors by an as yet undefined mechanism.

LOX-1 transcription

The importance of the lectin-like oxidized LDL receptor (LOX-1) gene in cardiovascular and other diseases is slowly being revealed. LOX-1 gene expression appears to be a "canary in a coal mine" for atherogenesis, being strongly up-regulated early on in a number of cell types when they are activated, and predicting the sites of future disease. From this early time point the LOX-1 protein often participates in the disease process itself. While gene/protein expression can be regulated on a multiplicity of levels, the most basic and important mode of regulation is usually transcriptional. There are very few studies on the transcriptional regulation of the human LOX-1 promoter; fewer still on definitive mapping of the transcription factors involved. It is known that a wide variety of stimuli up-regulate LOX-1, usually/probably on the transcriptional level. Angiotensin II (Ang II) is one important regulator of renin-angiotensin system and stimulator LOX-1. Ang II is known to up-regulate LOX-1 transcription through an NF-kB motif located at nt -2158. Oxidized low density lipoprotein (ox-LDL) is another important cardiovascular regulator, particularly of atherosclerotic disease, and a strong stimulator of LOX-1. Ox-LDL is known to up-regulate LOX-1 transcription through an Oct-1 motif located at nt -1556. The subsequent enhanced LOX-1 receptor numbers and their binding by ox-LDL ligand triggers a positive feedback loop, increasing further LOX-1 expression, with a presently unknown regulatory governor. The Oct-1 gene also has its own Oct-1-driven positive feedback loop, which likely also contributes to LOX-1 up-regulation. There is also data which suggests the involvement of the transcription factor AP-1 during stimulation with Phorbol 12-myristate acetate. While the importance of NF-κB as a transcriptional regulator of cardiovascular-relevant genes is well known, the importance of Oct-1 is not. Data suggests that Oct-1-mediated up-regulation of transcription is an early event in the stimulation of LOX-1 by ox-LDL. Yet Oct-1 also down-regulates cardiovascular-relevant genes by suppressing NF-κB transactivation. Thus, Oct-1 is presently somewhat of an enigma, up-regulating and down-regulating genes seemingly at random without an overall theme (with the exception of cell cycle). Yet the up-regulation of LOX-1 by ox-LDL is a very important event in atherogenesis (both early and late) and Oct-1 is, therefore, an important transcriptional gatekeeper of this important atherogenic trigger.

Functional characterisation of bovine interleukin 8 promoter haplotypes in vitro

Interleukin 8 (IL-8) is a major mediator of the innate immune response and polymorphisms in this gene are associated with susceptibility to inflammatory disease in humans. The aim of this study was to characterise the promoter region of the bovine IL8 gene towards understanding its regulation and the effect of promoter polymorphisms on gene expression levels. Twenty-nine polymorphic sites were identified across a 2.1kb upstream promoter region of the IL8 gene including two insertion/deletion polymorphisms. Sequence analysis and SNP genotyping identified two distinct promoter haplotypes (IL8-h1 and IL8-h2), which were present at significantly different frequencies in two divergently selected cattle breeds - Holstein-Friesian and Norwegian Red (IL8-h1 at 48% and 80% respectively). IL8-h1 was functionally less responsive in unstimulated mammary epithelial cells and in response to stimulation with LPS or bovine TNF. Serial deletion analysis and in silico transcription-factor binding site analysis indicated that allele specific binding of the transcriptional repressor Oct-1 may account for the reduced sensitivity of IL8-h1. Our finding of genetic variation in the bovine IL8 promoter that differentially regulates its expression has significant functional implications for IL8 expression in vitro and which may impact on susceptibility to bovine infectious disease and inflammation.

Racial differences in tumor necrosis factor-α-induced endothelial microparticles and interleukin-6 production

African Americans (AA) tend to have heightened systemic inflammation and endothelial dysfunction. Endothelial microparticles (EMP) are released from activated/apoptotic endothelial cells (EC) when stimulated by inflammation. The purpose of our study was to assess EMP responses to inflammatory cytokine (TNF-α) and antioxidant (superoxide dismutase, SOD) conditions in human umbilical vein ECs (HUVECs) obtained from AA and Caucasians. EMPs were measured under four conditions: control (basal), TNF-α, SOD, and TNF-α + SOD. Culture supernatant was collected for EMP analysis by flow cytometry and IL-6 assay by ELISA. IL-6 protein expression was assessed by Western blot. AA HUVECs had greater EMP levels under the TNF-α condition compared to the Caucasian HUVECs (6.8 ± 1.1 vs 4.7% ± 0.4%, P = 0.04). The EMP level increased by 89% from basal levels in the AA HUVECs under the TNF-α condition (P = 0.01) compared to an 8% increase in the Caucasian HUVECs (P = 0.70). Compared to the EMP level under the TNF-α condition, the EMP level in the AA HUVECs was lower under the SOD only condition (2.9% ± 0.3%, P = 0.005) and under the TNF-α + SOD condition (2.1% ± 0.4%, P = 0.001). Basal IL-6 concentrations were 56.1 ± 8.8 pg/mL/μg in the AA and 30.9 ± 14.9 pg/mL/μg in the Caucasian HUVECs (P = 0.17), while basal IL-6 protein expression was significantly greater (P < 0.05) in the AA HUVECs. These preliminary observational results suggest that AA HUVECs may be more susceptible to the injurious effects of the proinflammatory cytokine, TNF-α.

Genome-wide approaches reveal functional interleukin-4-inducible STAT6 binding to the vascular cell adhesion molecule 1 promoter

Endothelial cell activation and dysfunction underlie many vascular disorders, including atherosclerosis and inflammation. Here, we show that interleukin-4 (IL-4) markedly induced vascular cell adhesion molecule 1 (VCAM-1), both in cultured endothelial cells and in the intact endothelium in mice. Combined treatment with IL-4 and tumor necrosis factor alpha (TNF-α) resulted in further, sustained induction of VCAM-1 expression. IL-4-mediated induction of VCAM-1 and secondary monocyte adhesion was predominantly regulated by the transcription factor STAT6. Genome-wide survey of IL-4-mediated STAT6 binding from sequential chromatin-immunoprecipitation with deep sequencing (chromatin immunoprecipitation sequencing [ChIP-seq]) in endothelial cells revealed regions of transient and sustained transcription factor binding. Through the combination of DNA microarrays and ChIP-seq at the same time points, the majority of IL-4-responsive genes were shown to be STAT6 dependent and associated with direct STAT6 binding to their promoter. IL-4-mediated stable binding of STAT6 led to sustained target gene expression. Moreover, our strategy led to the identification of a novel functionally important STAT6 binding site within 16 kb upstream of the VCAM-1 gene. Taken together, these findings support a critical role for STAT6 in mediating IL-4 signal transduction in endothelial cells. Identification of a novel IL-4-mediated VCAM-1 enhancer may provide a foundation for targeted therapy in vascular disease.

Rosuvastatin prevents proteinuria and renal inflammation in nitric oxide-deficient rats

OBJECTIVE

The aim of the present study was to assess the effects of rosuvastatin on renal injury and inflammation in a model of nitric oxide deficiency.

METHODS

Male Wistar rats were randomly divided into four groups (n = 10/group) and treated for 28 days with saline (CTRL); 30 mg/kg/day L-NAME (L-name); L-NAME and 20 mg/kg/day rosuvastatin (L-name+ROS-20); or L-NAME and 2 mg/kg/day rosuvastatin (L-name+ROS-2). Systolic blood pressure was measured by plethysmography in the central artery of the tail. The serum total cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatinine, nitric oxide, interleukin-6, and tumor necrosis factor alpha levels were analyzed. Urine samples were taken to measure the albumin: urinary creatinine ratio. Kidneys were sectioned and stained with hematoxylin/eosin and Masson's trichrome. Immunohistochemical analysis of the renal tissue was performed to detect macrophage infiltration of the glomeruli.

RESULTS

The systolic blood pressure was elevated in the L-name but not the L-name+rosuvastatin-20 and L-name+rosuvastatin-2 groups. The L-name group had a significantly reduced nitric oxide level and an increased interleukin-6 and tumor necrosis factor alpha level, albumin: urinary creatinine ratio and number of macrophages in the renal glomeruli. Rosuvastatin increased the nitric oxide level in the L-name+rosuvastatin-2 group and reduced the interleukin-6 and tumor necrosis factor alpha levels, glomerular macrophage number and albumin:urinary creatinine ratio in the L-name+rosuvastatin-20 and L-name+rosuvastatin-2 groups.

CONCLUSION

Rosuvastatin treatment reduced glomerular damage due to improvement in the inflammatory pattern independent of the systolic blood pressure and serum lipid level. These effects may lead to improvements in the treatment of kidney disease.

Association of the POU class 2 homeobox 1 gene (POU2F1) with susceptibility to Type 2 diabetes in Chinese populations

AIMS

POU class 2 homeobox 1 (POU2F1), also known as octamer-binding transcription factor-1 (OCT-1), is a ubiquitous transcription factor that plays a key role in the regulation of genes related to inflammation and cell cycles. POU2F1 is located on chromosome 1q24, a region with linkage for Type 2 diabetes in Chinese and other populations. We examined the association of POU2F1 genetic variants with Type 2 diabetes in Hong Kong Chinese using two independent cohorts.

METHODS

We genotyped five haplotype-tagging single nucleotide polymorphisms at POU2F1 in 1378 clinic-based patients with Type 2 diabetes and 601 control subjects, as well as 707 members from 179 families with diabetes.

RESULTS

We found significant associations of rs4657652, rs7532692, rs10918682 and rs3767434 (OR = 1.26-1.59, 0.0003 < P(unadjusted) < 0.035) with Type 2 diabetes in the clinic-based case-control cohorts. Rs3767434 was also associated with Type 2 diabetes (OR = 1.55, P(unadjusted) = 0.013) in the family-based cohort. Meta-analysis revealed similar associations. In addition, the risk G allele of rs10918682 showed increased usage of insulin treatment during a mean follow-up period of 7 years [hazard ratio = 1.50 (1.05-2.14), P = 0.025].

CONCLUSIONS

Using separate cohorts, we observed consistent results showing the contribution of multiple variants at POU2F1 to the risk of Type 2 diabetes.

Oct1 is a switchable, bipotential stabilizer of repressed and inducible transcriptional states

Little is known regarding how the Oct1 transcription factor regulates target gene expression. Using murine fibroblasts and two target genes, Polr2a and Ahcy, we show that Oct1 recruits the Jmjd1a/KDM3A lysine demethylase to catalyze the removal of the inhibitory histone H3K9 dimethyl mark and block repression. Using purified murine T cells and the Il2 target locus, and a colon cancer cell line and the Cdx2 target locus, we show that Oct1 recruits the NuRD chromatin-remodeling complex to promote a repressed state, but in a regulated manner can switch to a different capacity and mediate Jmjd1a recruitment to block repression. These findings indicate that Oct1 maintains repression through a mechanism involving NuRD and maintains poised gene expression states through an antirepression mechanism involving Jmjd1a. We propose that, rather than acting as a primary trigger of gene activation or repression, Oct1 is a switchable stabilizer of repressed and inducible states.

MEOX2 regulates nuclear factor-kappaB activity in vascular endothelial cells through interactions with p65 and IkappaBbeta

AIMS

Tumours secrete proangiogenic factors to induce the ingrowth of blood vessels, the end targets of which are vascular endothelial cells (ECs). The MEOX2 homeoprotein inhibits nuclear factor-kappaB (NF-kappaB) signalling and EC activation in response to serum and proangiogenic factors. We hypothesize that MEOX2 interacts with components of this pathway in vascular ECs to modulate NF-kappaB activity and EC activation and that these interactions depend upon specific domains within the MEOX2 protein.

METHODS AND RESULTS

To test our hypothesis, we transduced ECs with MEOX2 expression constructs. MEOX2 protein localized to the nuclear fraction, as did IkappaBbeta and p65. By co-immunoprecipitation, MEOX2 bound to both p65 and IkappaBbeta. Immunofluorescence demonstrated that MEOX2 colocalizes in the nucleus with both p65 and IkappaBbeta and that this colocalization requires the MEOX2 homeodomain and N-terminal domain. Finally, promoter assays revealed that MEOX2 expression has a biphasic effect on NF-kappaB-dependent promoters. At low levels, MEOX2 stimulates NF-kappaB activity, whereas at high levels, it represses, effects that also depend upon the homeodomain and the N-terminal domain.

CONCLUSION

Our results represent the first report of an interaction between a homeobox protein and IkappaBbeta and suggest that MEOX2 modulates the activity of the RelA complex through direct interaction with its components. These observations implicate MEOX2 as a potentially important regulatory gene inhibiting not only the angiogenic response of ECs to proangiogenic factors, but also their response to chronic inflammatory stimulation that normally activates NF-kappaB, suggesting MEOX2 as a possible molecular target for the therapy of angiogenesis-dependent diseases such as cancer.

NF-kappaB balances vascular regression and angiogenesis via chromatin remodeling and NFAT displacement

Extracellular factors control the angiogenic switch in endothelial cells (ECs) via competing survival and apoptotic pathways. Previously, we showed that proangiogenic and antiangiogenic factors target the same signaling molecules, which thereby become pivots of angiogenic balance. Here we show that in remodeling endothelium (ECs and EC precursors) natural angiogenic inhibitors enhance nuclear factor-kappaB (NF-kappaB) DNA binding, which is critical for antiangiogenesis, and that blocking the NF-kappaB pathway abolishes multiple antiangiogenic events in vitro and in vivo. NF-kappaB induction by antiangiogenic molecules has a dual effect on transcription. NF-kappaB acts as an activator of proapoptotic FasL and as a repressor of prosurvival cFLIP. On the FasL promoter, NF-kappaB increases the recruitment of HAT p300 and acetylated histones H3 and H4. Conversely, on cFLIP promoter, NF-kappaB increases histone deacetylase 1 (HDAC1), decreases p300 and histone acetylation, and reduces the recruitment of NFAT, a transcription factor critical for cFLIP expression. Finally, we found a biphasic effect, when HDAC inhibitors (HDACi) were used to test the dependence of pigment epithelial-derived factor activity on histone acetylation. The cooperative effect seen at low doses switches to antagonistic as the concentrations increase. Our study defines an interactive transcriptional network underlying angiogenic balance and points to HDACi as tools to manipulate the angiogenic switch.

Feed-forward signaling of TNF-alpha and NF-kappaB via IKK-beta pathway contributes to insulin resistance and coronary arteriolar dysfunction in type 2 diabetic mice

We hypothesized that the interaction between tumor necrosis factor-alpha (TNF-alpha)/nuclear factor-kappaB (NF-kappaB) via the activation of IKK-beta may amplify one another, resulting in the evolution of vascular disease and insulin resistance associated with diabetes. To test this hypothesis, endothelium-dependent (ACh) and -independent (sodium nitroprusside) vasodilation of isolated, pressurized coronary arterioles from mLepr(db) (heterozygote, normal), Lepr(db) (homozygote, diabetic), and Lepr(db) mice null for TNF-alpha (db(TNF-)/db(TNF-)) were examined. Although the dilation of vessels to sodium nitroprusside was not different between Lepr(db) and mLepr(db) mice, the dilation to ACh was reduced in Lepr(db) mice. The NF-kappaB antagonist MG-132 or the IKK-beta inhibitor sodium salicylate (NaSal) partially restored nitric oxide-mediated endothelium-dependent coronary arteriolar dilation in Lepr(db) mice, but the responses in mLepr(db) mice were unaffected. The protein expression of IKK-alpha and IKK-beta were higher in Lepr(db) than in mLepr(db) mice; the expression of IKK-beta, but not the expression of IKK-alpha, was attenuated by MG-132, the antioxidant apocynin, or the genetic deletion of TNF-alpha in diabetic mice. Lepr(db) mice showed an increased insulin resistance, but NaSal improved insulin sensitivity. The protein expression of TNF-alpha and NF-kappaB and the protein modification of phosphorylated (p)-IKK-beta and p-JNK were greater in Lepr(db) mice, but NaSal attenuated TNF-alpha, NF-kappaB, p-IKK-beta, and p-JNK in Lepr(db) mice. The ratio of p-insulin receptor substrate (IRS)-1 at Ser307 to IRS-1 was elevated in Lepr(db) compared with mLepr(db) mice; both NaSal and the JNK inhibitor SP-600125 reduced the p-IRS-1-to-IRS-1 ratio in Lepr(db) mice. MG-132 or the neutralization of TNF-alpha reduced superoxide production in Lepr(db) mice. In conclusion, our results indicate that the interaction between NF-kappaB and TNF-alpha signaling induces the activation of IKK-beta and amplifies oxidative stress, leading to endothelial dysfunction in type 2 diabetes.

Role of TNF-alpha in vascular dysfunction

Healthy vascular function is primarily regulated by several factors including EDRF (endothelium-dependent relaxing factor), EDCF (endothelium-dependent contracting factor) and EDHF (endothelium-dependent hyperpolarizing factor). Vascular dysfunction or injury induced by aging, smoking, inflammation, trauma, hyperlipidaemia and hyperglycaemia are among a myriad of risk factors that may contribute to the pathogenesis of many cardiovascular diseases, such as hypertension, diabetes and atherosclerosis. However, the exact mechanisms underlying the impaired vascular activity remain unresolved and there is no current scientific consensus. Accumulating evidence suggests that the inflammatory cytokine TNF (tumour necrosis factor)-α plays a pivotal role in the disruption of macrovascular and microvascular circulation both in vivo and in vitro. AGEs (advanced glycation end-products)/RAGE (receptor for AGEs), LOX-1 [lectin-like oxidized low-density lipoprotein receptor-1) and NF-κB (nuclear factor κB) signalling play key roles in TNF-α expression through an increase in circulating and/or local vascular TNF-α production. The increase in TNF-α expression induces the production of ROS (reactive oxygen species), resulting in endothelial dysfunction in many pathophysiological conditions. Lipid metabolism, dietary supplements and physical activity affect TNF-α expression. The interaction between TNF-α and stem cells is also important in terms of vascular repair or regeneration. Careful scrutiny of these factors may help elucidate the mechanisms that induce vascular dysfunction. The focus of the present review is to summarize recent evidence showing the role of TNF-α in vascular dysfunction in cardiovascular disease. We believe these findings may prompt new directions for targeting inflammation in future therapies.

Lamin B1 controls oxidative stress responses via Oct-1

Interaction of lamins with chromatin and transcription factors regulate transcription. Oct-1 has previously been shown to colocalize partly with B-type lamins and is essential for transcriptional regulation of oxidative stress response genes. Using sequential extraction, co-immunoprecipitation (IP), fluorescence loss in photobleaching, and fluorescence resonance energy transfer, we confirm Oct-1-lamin B1 association at the nuclear periphery and show that this association is lost in Lmnb1(Delta/Delta) cells. We show that several Oct-1-dependent genes, including a subset involved in oxidative stress response, are dysregulated in Lmnb1(Delta/Delta) cells. Electrophoretic mobility shift assay and chromatin IP reveal that Oct-1 binds to the putative octamer-binding sequences of the dysregulated genes and that this activity is increased in cells lacking functional lamin B1. Like Oct1(-/-) cells, Lmnb1(Delta/Delta) cells have elevated levels of reactive oxygen species and are more susceptible to oxidative stress. Sequestration of Oct-1 at the nuclear periphery by lamin B1 may be a mechanism by which the nuclear envelope can regulate gene expression and contribute to the cellular response to stress, development, and aging.

Regulation of the RelA (p65) transactivation domain

The RelA (p65) NF-kappaB (nuclear factor kappaB) subunit contains an extremely active C-terminal transcriptional activation domain, required for its cellular function. In the present article, we review our knowledge of this domain, its modifications and its known interacting proteins. Moreover, we discuss how analysis of its evolutionary conservation reveals distinct subdomains and conserved residues that might give insights into its regulation and function.

Oct-1 induces pituitary tumor transforming gene expression in endocrine tumors

As human pituitary tumor transforming gene (hPTTG1) is upregulated in endocrine tumors, we studied regulatory mechanisms for hPTTG1 expression. We identified Oct-1-binding motifs in the hPTTG1 promoter region and show Oct-1-specific binding to the hPTTG1 promoter using chromatin immunoprecipitation. We overexpressed Oct-1 and observed approximately 2.5-fold activation of hPTTG1 promoter luciferase constructs (-2642/-1 and -1717/-1). Transcriptional activation was abrogated by co-transfection of an inactive Oct-1 form lacking the POU domain or by utilizing mutated hPTTG1 promoters or mutants devoid of two Oct-1-binding motifs (-1717/-1mut, -637/-1 or -433/-1). Using biotin-streptavidin pull-down assays, we confirmed Oct-1 binding to the two octamer motifs in the hPTTG1 promoter (-1669/-1631 and -1401/-1361). Endogenous hPTTG1 mRNA and protein increased up to approximately fourfold in Oct-1 transfectants, as measured by real-time PCR and western blot. In contrast, siRNA-mediated suppression of endogenous Oct-1 attenuated both the hPTTG1 mRNA and protein levels. Using confocal immunofluorescence imaging, Oct-1 and hPTTG1 were concordantly upregulated in pituitary (57 and 62%, n=79, P<0.01) and breast tumor specimens (57 and 42%, n=77, P<0.05) respectively. The results show that Oct-1 transactivates hPTTG1, and both proteins are concordantly overexpressed in endocrine tumors, thus offering a mechanism for endocrine tumor hPTTG1 abundance.

Homocysteine induces VCAM-1 gene expression through NF-kappaB and NAD(P)H oxidase activation: protective role of Mediterranean diet polyphenolic antioxidants

Hyperhomocysteinemia is a recognized risk factor for vascular disease, but pathogenetic mechanisms involved in its vascular actions are largely unknown. Because VCAM-1 expression is crucial in monocyte adhesion and early atherogenesis, we evaluated the NF-kappaB-related induction of VCAM-1 by homocysteine (Hcy) and the possible inhibitory effect of dietary polyphenolic antioxidants, such as trans-resveratrol (RSV) and hydroxytyrosol (HT), which are known inhibitors of NF-kappaB-mediated VCAM-1 induction. In human umbilical vein endothelial cells (HUVEC), Hcy, at 100 micromol/l, but not cysteine, induced VCAM-1 expression at the protein and mRNA levels, as shown by enzyme immunoassay and Northern analysis, respectively. Transfection studies with deletional VCAM-1 promoter constructs demonstrated that the two tandem NF-kappaB motifs in the VCAM-1 promoter are necessary for Hcy-induced VCAM-1 gene expression. Hcy-induced NF-kappaB activation was confirmed by EMSA, as shown by the nuclear translocation of its p65 (RelA) subunit and the degradation of the inhibitors IkappaB-alpha and IkappaB-beta by Western analysis. Hcy also increased intracellular reactive oxygen species by NAD(P)H oxidase activation, as shown by the membrane translocation of its p47(phox) subunit. NF-kappaB inhibitors decreased Hcy-induced intracellular reactive oxygen species and VCAM-1 expression. Finally, we found that nutritionally relevant concentrations of RSV and HT, but not folate and vitamin B6, reduce (by >60% at 10(-6) mol/l) Hcy-induced VCAM-1 expression and monocytoid cell adhesion to the endothelium. These data indicate that pathophysiologically relevant Hcy concentrations induce VCAM-1 expression through a prooxidant mechanism involving NF-kappaB. Natural Mediterranean diet antioxidants can inhibit such activation, suggesting their possible therapeutic role in Hcy-induced vascular damage.