Soluble analog of ApoER2 targeting beta2-glycoprotein I in immune complexes counteracts hypertension in lupus-prone mice with spontaneous antiphospholipid syndrome.

UNLABELLED: Essentials (NZWxBXSB)F1 male mice develop antibodies beta2-glycoprotein I (ß2GPI) and hypertension. A1-A1 is a soluble analogue of ApoE receptor 2 with a high affinity for ß2GPI/antibody complexes. A1-A1 improved blood pressure and arterial elastance in (NZWxBXSB)F1 male mice. A1-A1 had no adverse effects on the hemodynamics of healthy mice. SUMMARY: Background Antiphospholipid syndrome (APS) is diagnosed based on the presence of antiphospholipid antibodies and clinical thrombosis or fetal loss during pregnancy. Lupus-prone (NZWxBXSB)F1 male mice are the mouse model of spontaneous APS. They develop anti-ß2GPI antibodies, microinfarcts and hypertension. ApoER2 is a receptor that contributes to anti-ß2GPI-dependent thrombosis in APS by down-regulating endothelial nitric oxide synthase activation. Objectives A1-A1 is a small protein constructed from two identical ligand-binding modules from ApoER2, containing the binding site for ß2GPI. We studied how treatment with A1-A1 affects the development of hypertension in (NZWxBXSB)F1 male mice. Methods We treated (NZWxBXSB)F1 male mice with A1-A1 for up to 4 weeks and examined changes in hemodynamics by left ventricular pressure-volume loop measurements. Results We observed improvements in blood pressure in the A1-A1 treated mice. A1-A1 prevented the deterioration of arterial elastance by decreasing systemic resistance and improving vessel compliance. We did not detect any adverse effects of the treatment in either male mice or in apparently healthy female (NZWxBXSB)F1 mice. Conclusions We demonstrated that A1-A1, which is a soluble analog of ApoER2 that binds pathological ß2GPI/anti-ß2GPI complexes, has a positive impact on hemodynamics in lupus-prone mice with spontaneous anti-ß2GPI antibodies and hypertension.

[GENETIC AND EPIGENETIC DETERMINANTS OF ALZHEIMER'S DISEASE].

Alzheimer's disease (AD) is one of the most important economic, medical and social problems in modern society. Numerous studies have highlighted the role of genetic and epigenetic factors in this disease. Increased risk of AD is associated with certain polymorphic variants of the APOE gene, as well as some other, less affecting genes. In the review, recent studies demonstrating the role of genetic and epigenetic factors in the etiology and pathogenesis of AD are discussed.

Reciprocal cross differences in Drosophila melanogaster longevity: an evidence for non-genomic effects in heterosis phenomenon?

Reciprocal cross effects (i.e., differences between reciprocal hybrids that are developed by reversing the strains from which the dam and the sire are taken) are commonly used as a measure of sex-linkage or maternal effects. However, the papers reporting parental effects on life span of experimental animals are scarce. In order to investigate the potential of parent-of-origin effects for the longevity of hybrids, we determined the life spans of the inbred lines of Drosophila melanogaster [Oregon-R (OR), Canton-S (CS) and Uman (Um)] that differ significantly in longevity, as well as the life span of the progeny from the reciprocal crosses among them. The hybridization caused the increase in both flies' mean and maximum life span mainly shifting the survival curves upward proportionally at all ages. This resulted in the reduction in the Gompertz intercept (frailty) whereas the Gompertz slope (the rate of aging) was predominantly unchanged. Better-parent heterosis was observed in hybrids between OR and Um inbred lines and the extent of heterosis was more pronounced in hybrids between CS and Um inbred lines if long-lived parent was used as the female parent, and short-lived parent was used as the male parent in the crossing scheme. Such discrepancy in life span between reciprocal crosses may indicate that non-chromosomal factors are significantly contributing to a heterotic response. Our data are in line with the previous reports suggesting the involvement of non-genomic factors, particularly epigenetic events attributed to hybridization, in the manifestation of heterosis.

3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors upregulate inducible NO synthase expression and activity in vascular smooth muscle cells.

Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase ameliorate atherosclerosis by both cholesterol-dependent and cholesterol-independent mechanisms. We examined whether HMG-CoA reductase inhibitors affect the expression and activity of inducible NO synthase (iNOS) in cultured rat aortic vascular smooth muscle (VSM) cells. Atorvastatin (34 to 68 micromol/L) markedly increased nitrite production, an increase that was essentially abrogated by the NO synthase inhibitor N(G)-monomethyl-L-arginine (500 micromol/L). Activity of iNOS, determined by the conversion of L-arginine to L-citrulline, increased 9-fold after atorvastatin treatment. Western blot and semiquantitative reverse transcriptase-polymerase chain reaction revealed that atorvastatin (34 to 68 micromol/L) strongly upregulated iNOS protein and mRNA levels, respectively. These concentrations of atorvastatin did not cause cytotoxicity, as judged by the cell survival rate. Similarly, simvastatin and lovastatin (34 micromol/L) caused robust upregulation of the iNOS protein level. Transfection experiments demonstrated that the -1034- to 88-bp human iNOS promoter was strongly induced by atorvastatin (34 micromol/L). Electromobility and supershift assays using a nuclear factor-kappaB (NF-kappaB) consensus oligonucleotide and nuclear extracts from VSM cells as well as transfection studies using an NF-kappaB reporter plasmid suggested that the transcriptional activation of the iNOS gene by atorvastatin is not mediated via the NF-kappaB pathway. We conclude that HMG-CoA reductase inhibitors potently upregulate iNOS expression and activity in VSM cells, at least in part, by transcriptional mechanisms that do not depend on transcription factor NF-kappaB. These effects might have important implications for the impact of HMG-CoA reductase inhibitors on atherosclerosis.

Transcriptional regulation of the human iNOS gene by IL-1beta in endothelial cells.

BACKGROUND: Vascular endothelium participates in the control of vascular tone and function via the release of nitric oxide (NO) by the endothelial-type NO synthase (eNOS). Inducible NO synthase (iNOS) expression in endothelial cells occurs in many clinical conditions following induction by lipopolysaccharide or cytokines and generates large quantities of NO that result in endothelial cell activation and dysfunction. No information exists on the transcriptional regulation of the human iNOS gene (or that of other species) in endothelial cells. MATERIALS AND METHODS: We examined the transcriptional regulation of the human iNOS gene by interleukin-1beta (IL-1beta) in rat pulmonary microvascular endothelial cells (PVEC) by transient cotransfections of different iNOS-promoter constructs and cDNA of different transcription factors and regulatory proteins. RESULTS: The -1034/+88 bp iNOS promoter was strongly induced by IL-1beta, the regulatory elements for such induction being localized downstream of -205 bp. Cotransfection experiments with NF-kappaB isoforms, IkappaB isoforms, and IKK mutants suggested that the NF-kappaB site at -115/-106 bp is important, but not sufficient, for induction of iNOS promoter and that the role of NF-kappaB is partially independent of its binding site. C/EBP sites within the -205/+88 bp region were shown to be responsible, along with NF-kappaB site, for induction of iNOS promoter by IL-1beta. Overexpression of C/EBPalpha, C/EBPdelta, and liver-enriched activator protein (LAP) activated the promoter, whereas overexpression of liver-enriched inhibitory protein (LIP) strongly suppressed it. C/EBPbeta (LAP and LIP isoforms) was constitutively present in PVEC and was induced (approximately 2-fold) by IL-1beta, whereas C/EBPdelta was not constitutively expressed but was strongly induced by IL-1beta. Both C/EBPbeta and C/EBPdelta participated in DNA-protein complex formation. CONCLUSION: Both NF-kappaB and C/EBP pathways are important for the transcriptional regulation of the human iNOS gene by IL-1beta in PVEC.

Transcriptional regulation of the human iNOS gene in vascular-smooth-muscle cells and macrophages: evidence for tissue specificity.

We have cloned the 5' upstream -1034 to +88 fragment of the human inducible nitric oxide synthase (hiNOS) gene and demonstrate its competence to promote luciferase gene transcription in vascular-smooth-muscle (VSM) cells and macrophages. Sequential 5' end-deletions localized positive regulatory elements of hiNOS transcription in VSM A7r5 cells downstream of nucleotide -205 and demonstrated the functional importance of the resident NF-kappaB site (nucleotides -115 to -106). The hiNOS promoter/enhancer was induced strongly by LPS and IFN-gamma, and modestly by IL-1beta in RAW 264.7 cells, but not in VSM cells. Truncation of the NF-kappaB site markedly diminished, but did not eliminate, LPS-inducibility. Sodium salicylate and ibuprofen down-regulated the basal transcriptional activity of the hiNOS promoter/enhancer in VSM but not in RAW 264.7 cells. These results indicate that the transcriptional regulation of the hiNOS gene features considerable complexity and tissue specificity.

Role of C/EBP proteins in hepatic and vascular smooth muscle transcription of human NHE1 gene.

We have recently shown that regulatory element D (nucleotides -239 to -215) of the 0.25-kb promoter of the human growth factor-activatable Na+/H+ exchanger (NHE1) is important for gene transcription in cells of hepatic origin (Hep G2) and vascular smooth muscle origin (VSM A7r5). This element contains a sequence (nucleotides -230 to -222) with complete homology to the C/EBP binding site. We now demonstrate that nucleotide substitution mutations disrupting this C/EBP site suppressed transcription in Hep G2 cells, VSM A7r5 cells, and Sprague-Dawley VSM cells in primary culture. These mutations abolished the binding of rat liver nuclear activities as well as transcription factors C/EBP alpha, C/EBP beta, and C/EBP delta expressed in COS-1 cell lysates to element D. Anti-C/EBP antibodies supershifted DNA-protein complexes formed between hepatic nuclear activities or C/EBP proteins expressed in COS-1 cell lysates and regulatory element D. Finally, cotransfection experiments of NHE1 0.25-kb promoter-chloramphenicol acetyltransferase (CAT) construct and C/EBP expression vectors showed that C/EBP alpha and C/EBP delta are transactivators of the NHE1 proximal promoter in Hep G2 and VSM A7r5 cells. These results indicate that members of the C/EBP family of transcription factors are involved in the regulation of hepatic and vascular smooth muscle transcription of the human NHE1 gene.

Proximal regulatory elements and nuclear activities required for transcription of the human Na+/H+ exchanger (NHE-1) gene.

We herein demonstrate competence of the 5' upstream region -1374 to +16 of the human growth factor-activatable Na+/H+ exchanger (NHE-1) gene to promote transcription of the chloramphenicol acetyltransferase gene in cells of hepatic origin (HepG2), vascular-smooth-muscle origin (VSM A7r5) and fibroblasts (3T3). We also describe the mapping of the regulatory elements required for such transcription. Sequential 5' end-deletions indicated that the 5' boundary of the positive regulatory elements of NHE-1 transcription is localized downstream of nucleotide -252 in both HepG2 and VSM A7r5 cells but downstream of nucleotide -654 in 3T3 cells. Footprinting analysis of the 0.25-kb promoter fragment using rat liver nuclear extracts identified 4 protected regions as follows: A, -31 to -9; B, -108 to -65; C, -124 to -111; and D, -239 to -215. Internal deletion and nucleotide substitutions within regulatory element D revealed its essential role for transcription of the human NHE-1 gene in HepG2 and VSM A7r5 cells. DNA binding and competition assays using rat liver nuclear extracts indicated that regulatory element D is recognized by 5 nuclear activities. Four of these activities (designated as NHE-1D1-4) are competed out completely by oligonucleotides containing the binding sites of transcription factors CREB, AP3, NFY, and other CCAAT box-binding proteins (C/EBP alpha or related proteins). This competition profile might be explained by the presence of homology between regulatory element D and the consensus sequence of C/EBP as well as the other competitor oligonucleotides. The actual relationship between these nuclear activities and the C/EBP family of proteins (or other transcription factors) remains to be determined.

Regulation of CYP1A induction in hepatoma 27 depending on the site of transplantation.

1. Rat hepatoma 27 after intrahepatic transplantation shows a low but detectable level of cytochrome P450 and P450-dependent activities. The same hepatoma transplanted intramuscularly does not show a detectable amount of cytochrome P450 and P450-dependent activities. 2. Different types of cytochrome P4501A inducers were able to induce 1A isoforms in the intrahepatic hepatoma 27 transplants but not in the intramuscular transplants. 3. Immunohistochemical analysis demonstrates that not all cells in hepatoma 27 transplanted into the liver could be induced with 1A-inducer. The cells of the adenomatous structures of hepatoma 27 are not reactive with 1A antibodies.