Association of polymorphic markers of CCL2 gene with essential hypertension

Chemokine CCL2, or monocytic chemoatractant protein 1 (CCL2/MCP-1) plays an important role in the development of cardiovascular diseases. In the present study, genotypes of four polymorphic markers (rs1860190, rs1024611, rs3917887, and rs991804) of the CCL2gene were identified in the population of Tatars (residents of the Republic of Bashkortostan). Analysis of associations of these markers with essential hypertension (EH) was carried out. It was demonstrated that haplotype CCL2*A*G*D*T was associated with the increased risk of EH (P = 0.01; OR = 1.53).     

Microsomal prostaglandin E synthase-2 is not essential for in vivo prostaglandin E2 biosynthesis

Prostaglandin E₂ (PGE₂) plays an important role in the normal physiology of many organ systems. Increased levels of this lipid mediator are associated with many disease states, and it potently regulates inflammatory responses. Three enzymes capable of in vitro synthesis of PGE₂ from the cyclooxygenase metabolite PGH₂ have been described. Here, we examine the contribution of one of these enzymes to PGE₂ production, mPges-2, which encodes microsomal prostaglandin synthase-2 (mPGES-2), by generating mice homozygous for the null allele of this gene. Loss of mPges-2 expression did not result in a measurable decrease in PGE₂ levels in any tissue or cell type examined from healthy mice. Taken together, analysis of the mPGES-2 deficient mouse lines does not substantiate the contention that mPGES-2 is a PGE₂ synthase.     

Characterization of gastric mucosal prostaglandin E2 receptor

1. The binding characteristics of gastric mucosal prostaglandin (PG) E2 (PGE2) receptor were investigated using mucosal cell membranes from rat stomach. The binding was found to be dependent upon PGE2 and membrane protein concentration, the time of incubation and the pH of the mixture, being highest at pH 3.0. 2. Scatchard analysis of the binding data revealed a curvilinear plot with high affinity binding (Kd = 2 nM; Bmax = 0.106 pmol/mg protein) and low affinity binding (Kd = 319 nM; Bmax = 2.262 pmol/mg protein) sites. 3. Competitive displacement study indicated that the receptor was specific for PGs of the E series, as PGF2 alpha and 6-keto-PGF1 alpha failed to displace the PGE2. 4. The study is the first report to provide biochemical parameters of specific PGE receptors in rat gastric mucosa.     

Impaired bone resorption to prostaglandin E2 in prostaglandin E receptor EP4-knockout mice

Prostaglandin E(2) (PGE(2)) acts as a potent stimulator of bone resorption. In this study, we first clarified in normal ddy mice the involvement of protein kinase A and induction of matrix metalloproteinases (MMPs) in PGE(2)-induced bone resorption, and then identified PGE receptor subtype(s) mediating this PGE(2) action using mice lacking each subtype (EP1, EP2, EP3, and EP4) of PGE receptor. In calvarial culture obtained from normal ddy mice, both PGE(2) and dibutyryl cyclic AMP (Bt(2)cAMP) stimulated bone resorption and induced MMPs including MMP-2 and MMP-13. Addition of an inhibitor of protein kinase A, H89, or an inhibitor of MMPs, BB94, significantly suppressed bone-resorbing activity induced by PGE(2.) In calvarial culture from EP1-, EP2-, and EP3-knockout mice, PGE(2) stimulated bone resorption to an extent similar to that found in calvaria from the wild-type mice. On the other hand, a marked reduction in bone resorption to PGE(2) was found in the calvarial culture from EP4-knockout mice. The impaired bone resorption to PGE(2) was also detected in long bone cultures from EP4-knockout mice. Bt(2)cAMP greatly stimulated bone resorption similarly in both wild-type and EP4-knockout mice. Induction of MMP-2 and MMP-13 by PGE(2) was greatly impaired in calvarial culture from EP4-knockout mice, but Bt(2)cAMP stimulated MMPs induction similarly in the wild-type and EP4-knockout mice. These findings suggest that PGE(2) stimulates bone resorption by a cAMP-dependent mechanism via the EP4 receptor.     

Association between the angiotensin-converting enzyme gene insertion/deletion polymorphism and essential hypertension in young Pakistani patients

Several studies have demonstrated the importance of angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphisms in the pathogenesis of hypertension. This study sought to determine the association between the ACE I/D polymorphism and essential hypertension in young Pakistanis. The frequency of the ACE I/D polymorphism was established by a comparative cross-sectional survey of Pakistani patients suffering from essential hypertension and ethnically matched normotensive controls. Samples were collected from tertiary care hospitals in northern Pakistan. Hypertensive individuals were defined as those with a systolic blood pressure > 140 mmHg and/or diastolic blood pressure > 90 mmHg on three separate occasions, or those currently receiving one, or more, anti-hypertensive agents. DNA samples obtained from hypertensive (n = 211) and normotensive (n = 108) individuals were typed by PCR. The frequency of the ACE I/I genotype was significantly higher in hypertensive patients, aged 20-40 years, than in normotensive controls of the same age group (chi(2) = 4.0, P = 0.041). Whereas no overall significant differences were observed between the I/I, I/D and D/D ACE genotypes (One way ANOVA, F = 0.672; P = 0.413). The association between the ACE I/I genotype and essential hypertension in individuals aged 相似文献   

Bleomycin-induced E prostanoid receptor changes alter fibroblast responses to prostaglandin E2

Although PGE(2) is a potent inhibitor of fibroblast function, PGE(2) levels are paradoxically elevated in murine lungs undergoing fibrotic responses. Pulmonary fibroblasts from untreated mice expressed all four E prostanoid (EP) receptors for PGE(2). However, following challenge with the fibrogenic agent, bleomycin, fibroblasts showed loss of EP2 expression. Lack of EP2 expression correlated with an inability of fibroblasts from bleomycin-treated mice to be inhibited by PGE(2) in assays of proliferation or collagen synthesis and blunted cAMP elevations in response to PGE(2). PGE(2) was similarly unable to suppress proliferation or collagen synthesis in fibroblasts from EP2(-/-) mice despite expression of the other EP receptors. EP2(-/-), but not EP1(-/-) or EP3(-/-) mice, showed exaggerated fibrotic responses to bleomycin administration in vivo as compared with wild-type controls. EP2 loss on fibroblasts was verified in a second model of pulmonary fibrosis using FITC. Our results for the first time link EP2 receptor loss on fibroblasts following fibrotic lung injury to altered suppression by PGE(2) and thus identify a novel fibrogenic mechanism.     

Association of a RFLP for the insulin receptor gene, but not insulin, with essential hypertension.

Insulin has cardiovascular actions and patients with essential hypertension display insulin resistance. A cross-sectional study of the R1 RFLP of the insulin receptor gene (INSR) was carried out in 67 hypertensive (HT) and 75 normotensive (NT) subjects whose parents had a similar blood pressure status at age greater than or equal to 50. The frequency of the minor (+) allele was 0.31 in HTs and 0.44 in NTs, and the difference between observed alleles in all subjects in each group was significant (chi 2 = 4.8, P less than 0.05). Allele frequencies of a BglI RFLP of the insulin gene, however, did not differ between the HT and NT groups. The data thus provide evidence in favour of an association of HT with a polymorphism at the INSR locus (19p13.3-13.2), so implicating this locus, and possibly a genetic variant of the insulin receptor itself, in HT.     

Evidence that the prostaglandin E2 receptor and the anhydrolevuglandin E2 receptor in the rat uterus are the same receptor.

Anhydrolevuglandin E2 (AnLGE2) is closely related to prostaglandin E2 (PGE2) and has been found to inhibit the uterotonic activity of PGE2. The binding of PGE2 and its inhibition by AnLGE2 has been determined in rat uterine membrane fractions. AnLGE2 inhibited the binding of 3HPGE2 in a dose related fashion. 3HAnLGE2 also binds to rat uterine membrane fractions and its binding is inhibited by PGE2 in a dose related fashion. These data support previous physiological observations that AnLGE2 inhibits the actions of PGE2 by acting at the PGE2 receptor. Thus, AnLGE2 appears to be a specific inhibitor of PGE2 actions at its uterine receptors.     

Effect of furosemide on urinary excretion of prostaglandin E in normal volunteers and pateints with essential hypertension

Urinary excretion of prostaglandin E was measured radioimmunologically in 19 healthy persons ( 15 men and 4 women ) and in 16 patients ( 10 men and 6 women ) with essential hypertension before and after the administration of furosemide. The excretion rates were increased from 26.3±3.0 to 64.5±11.3 ng/hr in the former and from 11.9±2.7 to 26.9±85 ng/hr in the latter. There was a significant difference between them, healthy subjects showing a greater increase than patients with essential hypertension.There was an obvious sexual difference in urinary excretion of prostaglandin. In men, greater increase in the excretion rates was found than in the women. Greater increases were also obtained in healthy men than in hypertensive men and in healthy women than in hypertensive women. The present results suggest that furosemide enhances urinary excretion of prostaglandin E by mechanisms which entails either an increase in prostaglandin synthesis or a decrease in renal metabolism.     

Angiotensin II type 1 receptor gene polymorphism and telomere shortening in essential hypertension

Several genetic studies were carried out among hypertensive patients to assess allelic association at the 1166 position of the 3' untranslated region of angiotensin II type 1 receptor gene. In addition, attempts have also been made to find out whether telomere length attrition is associated with hypertension. The main aim of this study was to examine the association of A1166C polymorphism of angiotensin II type 1 receptor and telomere length with essential hypertension in Egyptian people. Angiotensin II type 1 genotyping and relative telomere length were investigated by PCR in 40 patients of essential hypertension and 15 healthy controls. The homozygous AA1166 allele frequency was 92.8% among the studied subjects. There was no intergroup variation in A allele frequency in normotensive group. The frequency of homozygous A allele was significantly higher in hypertensive than normotensive subjects (97.5 and 80%, respectively) with higher frequencies in male patients. The average telomere length ratio was significantly shorter in hypertensive than in normal subjects (1.08?±?0.3 and 1.54?±?0.18, respectively). No correlation was observed between telomere length ratio and body mass index. This study suggests that the homozygous A1166 allele of angiotensin II type 1 and short telomeres may be predisposing factors for essential hypertension in Egyptians and may be involved in the pathogenesis of the disease. Further strategies for treating high-risk patients could result in prevention or delay of end organ damage.     

Decrease of prostaglandin E2 receptor binding is accompanied by reduced antilipolytic effects of prostaglandin E2 in isolated rat adipocytes

The effect of treatment of isolated rat adipocytes with prostaglandin E2 (PGE2) on subsequent [3H]PGE2 binding was studied. In addition, the antilipolytic effects of was studied. In addition, the antilipolytic effects of PGE2, adenosine, and insulin were studied in control and PGE2-treated adipocytes. Treatment of adipocytes with PGE2 (1 microM) decreased the binding of [3H]PGE2 by 61% (from 11.0 to 4.6 fmol/10(6) cells, P less than 0.005). Scatchard analysis of the binding data demonstrated that the decrease of PGE2 receptor binding was due to a decrease in the apparent number of PGE2 receptors while the apparent receptor affinity was unaltered. Reduction of the PGE2 receptor binding was specifically regulated inasmuch as structurally related compounds such as PGF2 alpha and arachidonic acid had only minor effects on subsequent [3H]PGE2 receptor binding. Reduction of the available receptor number was associated with a significant decrease in the antilipolytic effect of PGE2 on the isoproterenol-stimulated lipolysis (P less than 0.05). The maximal antilipolytic effect of PGE2 was decreased by 45%. Desensitization of the biological effect of PGE2 (antilipolysis) was only partially specifically regulated inasmuch as the antilipolytic compound phenylisopropyladenosine also had reduced antilipolytic effect in PGE2-treated cells. However, the antilipolytic effect of insulin was similar in control and PGE2-treated cells. It was found that the PGE2-induced decrease of [3H]PGE2 receptor binding may be due to a very tight coupling between the PGE2 molecule and its specific receptor. This tight coupling may then represent an occupancy of the receptor rather than a true loss of receptors.(ABSTRACT TRUNCATED AT 250 WORDS)     

ACE2基因多态性与高血压患者血压昼夜节律变化相关性研究

目的:研究血管紧张素转换酶2(ACE2)基因多态性与高血压患者血压昼夜节律变化的关系.方法:选择符合入选标准的高血压患者336例,采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)的方法,进行ACE2基因分型.根据血压昼夜节律变化,将高血压患者分为勺型与非勺型两组.分析基因型是否为非勺型血压的危险因素.结果:男性勺型组与非勺型组ACE2基因型多态性的分布存在显著差异,勺型组以G等位基因携带者为主.结论:ACE2基因多态性与男性高血压患者血压昼夜节律相关,携带G等位基因的患者可能更易发生夜间血压升高.     

Effect of deletion of the prostaglandin EP2 receptor on the anabolic response to prostaglandin E2 and a selective EP2 receptor agonist

Studies using prostaglandin E receptor (EP) agonists indicate that prostaglandin (PG) E(2) can have anabolic effects through both EP4 and EP2 receptors. We previously found that the anabolic response to a selective EP4 receptor agonist (EP4A, Ono Pharmaceutical) was substantially greater than to a selective EP2 receptor agonist (EP2A) in cultured murine calvarial osteoblastic cells. To further define the role of the EP2 receptor in PG-mediated effects on bone cells, we examined the effects of EP2A and PGE(2) on both calvarial primary osteoblasts (POB) and marrow stromal cells (MSC) cultured from mice with deletion of one (Het) or both (KO) alleles of the EP2 receptor compared to their wild-type (WT) littermates. Deletion of EP2 receptor was confirmed by quantitative real-time PCR, Western blot and immunohistochemistry. The 1 month-old mice used to provide cells in these studies did not show any significant differences in their femurs by static histomorphometry. EP2A was found to enhance osteoblastic differentiation as measured by alkaline phosphatase mRNA expression and activity as well as osteocalcin mRNA expression and mineralization in the WT cell cultures from both marrow and calvariae. The effects were somewhat diminished in cultures from Het mice and abrogated in cultures from KO mice. PGE(2) effects were greater than those of EP2A, particularly in POB cultures and were only moderately diminished in Het and KO cell cultures. We conclude that activation of the EP2 receptor is able to enhance differentiation of osteoblasts, that EP2A is a true selective agonist for this receptor and that PGE(2) has an additional anabolic effect likely mediated by the EP4 receptor.     

Epigenetic mechanisms regulate the prostaglandin E receptor 2 in breast cancer

The increase in local oestrogen production seen in oestrogen receptor positive (ER+) breast cancers is driven by increased activity of the aromatase enzyme. CYP19A1, the encoding gene for aromatase, is often overexpressed in the oestrogen-producing cells of the breast adipose fibroblasts (BAFs) surrounding an ER+ tumour, and the molecular processes underlying this upregulation is important in the development of breast-specific aromatase inhibitors for breast cancer therapy. Prostaglandin E2 (PGE2), a factor secreted by tumours, is known to stimulate CYP19A1 expression in human BAFs. The hormonal regulation of this process has been examined; however, what is less well understood is the emerging role of epigenetic mechanisms and how they modulate PGE2 signalling. This present study characterises the epigenetic processes underlying expression of the prostanoid receptor EP2 in the context of ER+ breast cancer. Sodium bisulphite sequencing of CpG methylation within the promoter region of EP2 revealed that an inverse correlation existed between methylation levels and relative EP2 expression in breast cancer cell lines MDA-MB-231, MCF7 and MCF10A but not in HS578t and T47D. Inhibition of DNA methylation with 5-aza-2'-deoxycytidine (5aza) and histone deacetylation with Trichostatin A (TSA) resulted in upregulation of EP2 mRNA in all cell lines with varying influences of each epigenetic process observed. Expression of EP2 was detected in human BAFs despite a natively methylated promoter, and this expression was further increased upon 5aza treatment. An examination of 3 triple negative, 3 ductal carcinoma in situ and 3 invasive ductal carcinoma samples revealed that there was no change in EP2 promoter methylation status between normal and cancer associated stroma, despite observed differences in relative mRNA levels. Although EP2 methylation status is inversely correlated to expression levels in established breast cancer cell lines, we could not identify that such a correlation existed in tumour-associated stroma cells.     

Association of a solubilized prostaglandin E2 receptor from renal medulla with a pertussis toxin-reactive guanine nucleotide regulatory protein

Prostaglandin E2 (PGE2) was found to bind specifically, reversibly, and in a protein-dependent manner to a single class of high affinity (KD approximately equal to 20 nM) binding sites in membranes prepared from canine renal outer medulla. PGE2 binding activity was solubilized from these membranes in a stable form (t1/2 greater than 14 days) in the absence of ligand in 75% yields using digitonin. The characteristics of PGE2 binding to membranes and solubilized protein were similar with respect to pH dependence, KD for PGE2, and order of potency of prostaglandins (PGE2 approximately PGE1 greater than PGF2 alpha greater than PGD2) in inhibiting the binding of [3H]PGE2. Importantly, the extents of binding of PGE2 to membranes and to a solubilized preparation partially purified by chromatography on wheat germ agglutinin-Affi-Gel 10 were both increased about 2-fold by GDP and GTP and its analogs. Treatment of the digitonin-solubilized PGE2 binding activity with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS) rendered the binding activity insensitive to stimulation by GTP and decreased the apparent molecular weight of the peak of PGE2 binding activity from about 175,000 to about 65,000. These results suggest that the PGE2 binding activity resides in a protein which is tightly associated with, but distinct from, a guanine nucleotide regulatory (N) protein. PGE2 (greater than or equal to 10 nM) was found to stimulate GTPase activity of renal outer medullary membranes, and this stimulation was eliminated by pretreatment of membranes with pertussis toxin and NAD, but not cholera toxin and NAD. Treatment of both particulate and solubilized preparations of PGE2 binding activity with pertussis toxin plus NAD also eliminated the ability of GTP to stimulate PGE2 binding. This evidence indicates that it is the inhibitory guanine nucleotide regulatory protein, Ni, with which the PGE2 binding activity is associated. Thus, this PGE2 binding activity is an inhibitory PGE2 receptor, quite possibly one that mediates inhibition of vasopressin-induced cAMP formation in the medullary thick ascending limb and/or collecting tubule of the kidney.     

Solubilization and purification of the prostaglandin E2 receptor from cardiac sarcolemma.

A prostaglandin E2 (PGE2) receptor was solubilized and isolated from cardiac sarcolemma membranes. Its binding characteristics are almost identical to those of the membrane bound receptor. [3H]PGE2 binding to solubilized and membrane bound receptor was sensitive to elevated temperature and no binding was observed in the absence of NaCl. No significant effects of DTT, ATP, Mg2+, Ca2+ or of changes in buffer pH were observed on [3H]PGE2 binding to either solubilized or membrane-bound receptor. Unlabelled PGE1 displaced over 90% of [3H]PGE2 from the CHAPS-solubilized receptor. PGD2, PGI2, PGF2 alpha and 6-keto-PGF1 alpha were not effective in displacing [3H]PGE2 from the receptor. Scatchard analysis of [3H]PGE2 binding to CHAPS-solubilized receptor revealed the presence of two types of PGE2 binding sites with Kd of 0.33 +/- 0.05 nM and 3.00 +/- 0.27 nM and Bmax of 0.5 +/- 0.04 and 2.0 +/- 0.1 pmol/mg of protein. The functional PGE2 receptor was isolated from CHAPS-solubilized SL membrane using two independent methods: first by a WGA-Sepharose chromatography and second by sucrose gradient density centrifugation. Receptor isolated by these two methods bound [3H]PGE2. Unlabelled PGE1 and PGE2 displaced [3H]PGE2 from the purified receptor. Scatchard analysis of [3H]PGE2 binding to purified receptor revealed the presence of the two binding sites as observed for the membrane bound and CHAPS-solubilized receptor. SDS-polyacrylamide gel electrophoresis of the purified receptor fractions revealed the presence of a protein band of M(r) of approx. 100,000. This 100-kDa was photolabelled with [3H]azido-PGE2, a photoactive derivative of PGE2. We propose that this 100-kDa protein is a cardiac PGE2 receptor.     

Association of a polymorphism of the angiotensin I-converting enzyme gene with essential hypertension.

Angiotensin I-converting enzyme (ACE) is responsible for production of angiotensin II and breakdown of kinins, leading to increased blood pressure (BP). Furthermore, ACE inhibitors are effective antihypertensive agents. A 287 bp insertion/deletion polymorphism in intron 16 of the ACE gene (ACE) was examined by PCR in a cross-sectional study of 80 hypertensive (HT) and 93 normotensive (NT) subjects whose parents had a similar BP status at age greater than or equal to 50. The frequency of the insertion allele was 0.56 in HTs and 0.41 in NTs, and the difference between observed alleles in all subjects in each group was significant (chi 2 = 7.6, P less than 0.01). The data thus provide evidence in favour of an association of HT with a polymorphism at the ACE locus (17q23), so implicating this locus, and possibly a genetic variant of ACE itself, in human essential hypertension.     

Association between relative bone mass and vitamin D receptor gene polymorphism

The paper reports a search for association between the relative bone tissue mass (percent of total body mass, %BT) and FokI (rs10735810), BsmI (rs1544410), and TaqαI (rs731236) vitamin D receptor gene polymorphisms. The group of apparently healthy young adults born in the central and northern regions of European Russia included 61 men and 60 women aged 16–23 years. No statistical association was detected between the FokI polymorphism and %BT. The carriers of the BsmI *A allele exhibited a higher %BT (p = 0.0172) compared to the subjects bearing the BsmI *G*G allele. The subjects with the *C*C TaqαI genotype were characterized by increased %BT compared to the carriers of the *T allele (p = 0.0018). The data are in good correspondence with the results obtained in the studies involving apparently healthy representatives of Central European and Northern European populations of the corresponding age.     

Lipopolysaccharide-dependent prostaglandin E(2) production is regulated by the glutathione-dependent prostaglandin E(2) synthase gene induced by the Toll-like receptor 4/MyD88/NF-IL6 pathway

Macrophages produce a large amount of PGE(2) during inflammation. This lipid mediator modulates various immune responses. PGE(2) acts on macrophages and inhibits production of cytokines such as TNF-alpha and IL-12. Membrane-bound glutathione-dependent PGE(2) synthase (mPGES) has been shown to be a terminal enzyme of the cyclooxygenase-2-mediated PGE(2) biosynthesis. Here we identified mPGES as a molecule that is induced by LPS in macrophages. The expression of mPGES was not induced by LPS in mice lacking Toll-like receptor 4 or MyD88. Furthermore, mice deficient in NF-IL6 showed neither induction of mPGES nor biosynthesis of PGE(2) in response to LPS, indicating that mPGES expression in response to LPS is regulated by a Toll-like receptor 4/MyD88/NF-IL6-dependent signaling pathway. We generated mPGES-deficient mice and investigated the role of mPGES in vivo. The mice showed no augmentation of the PGE(2) production in response to LPS. However, they were not impaired in the LPS-induced production of inflammatory cytokines and showed normal response to the LPS-induced shock. Thus, mPGES is critically involved in the biosynthesis of PGE(2) induced by LPS, but is dispensable for the modulation of inflammatory responses.