Natriuretic Peptide Precursor B Research Articles

Pleural Fluid-to-Blood BNP Ratio May Contribute to Prognosis in Malignant Pleural Mesothelioma.

Brain natriuretic peptide (BNP) seems to be produced from malignant mesothelial cells other than cardiomyocytes. We aimed to evaluate whether an increased pleural fluid-to-blood BNP ratio in patients with malignant pleural mesothelioma (MPM) could facilitate prognosis beyond diagnosis. Patients with MPM were included (observational study). One- and two-year survival and factors affecting it were tested. To evaluate the prognostic significance of the natriuretic peptide precursor B (NPPB) gene expression in MPM, we constructed a survival curve from data derived from The Cancer Genome Atlas. Nineteen consecutive patients with MPM were included (age: 67 (61, 80), male 78.9%). One- and two-year survival were 52.6% and 31.6%, respectively. Age, performance status, and the other variables tested did not differ between survivors and non-survivors. Non-survivors presented higher pleural fluid BNP in two years (699 (210, 5000) vs. 379.5 (5, 567), p = 0.036) and BNP ratios than survivors (1-year: 28.75 (4.05, 150.24) vs. 3.49 (0.3, 26) p = 0.001, 2-years: 22.8 (2.42, 150.24) vs. 3.49 (0.3, 7.76), p = 0.001). One- and two-year survival rates in patients with BNP ratios above/equal to the median value (8.82) were 20% and 0%, and 88.9% and 66.7%, respectively, in patients with BNP ratios below 8.82 (p = 0.006 and p = 0.002, respectively). MPM patients with low NPPB expression presented significantly higher survival rates compared to patients with higher expressions (p = 0.032). A high pleural fluid/blood BNP ratio, an easily performed in everyday practice, costless biomarker seems to predict poorer survival better than the commonly reported prognostic factors in MPM.

Cardiomyocyte behavior on biodegradable polyurethane/gold nanocomposite scaffolds under electrical stimulation

Following a myocardial infarction (MI), cardiomyocytes are replaced by scar tissue, which decreases ventricular contractile function. Tissue engineering is a promising approach to regenerate such damaged cardiomyocyte tissue. Engineered cardiac patches can be fabricated by seeding a high density of cardiac cells onto a synthetic or natural porous polymer. In this study, nanocomposite scaffolds made of gold nanotubes/nanowires incorporated into biodegradable castor oil-based polyurethane were employed to make micro-porous scaffolds. H9C2 cardiomyocyte cells were cultured on the scaffolds for one day, and electrical stimulation was applied to improve cell communication and interaction in neighboring pores. Cells on scaffolds were examined by fluorescence microscopy and scanning electron microscopy, revealing that the combination of scaffold design and electrical stimulation significantly increased cell confluency of H9C2 cells on the scaffolds. Furthermore, we showed that the gene expression levels of Nkx2.5, atrial natriuretic peptide (ANF) and natriuretic peptide precursor B (NPPB), which are functional genes of the myocardium, were up-regulated by the incorporation of gold nanotubes/nanowires into the polyurethane scaffolds, in particular after electrical stimulation.

Derivatives containing both coumarin and benzimidazole potently induce caspase-dependent apoptosis of cancer cells through inhibition of PI3K-AKT-mTOR signaling.

Coumarins are a large family of compounds derived from a wide range of plants, fungi, and bacteria, and coumarin derivatives can have extremely variable structures and consequently diverse biological properties including antitumor activity. Compounds that bear a benzimidazole moiety are known to possess antitumor activity and a variety of other biological activities. High-throughput screening of a compound library identified a coumarin-containing and a benzimidazole-containing compound [#32, 7-(diethylamino)-3-(1-methyl-1H-benzimidazol-2-yl)-2H-chromen-2-one] that has potent anticancer activity. Evaluation of 17 additional analogs further identified three compounds with anticancer activity in 14 different human cancer cell lines. Fluorescence-activated cell sorting and western blotting analyses suggested that these compounds can induce caspase-dependent apoptosis. Real-time reverse transcriptase PCR analyses of 26 cancer-related genes revealed that seven genes (NPPB, ATF3, DDIT4, CDH10, TSPAN14, TXNIP, and AXL) were significantly upregulated and nine genes (PAGE4, LRP8, SNCAIP, IGFBP5, SLCO2A1, CLDN2, ESRRG, D2HGDH, and PDGFRA) were significantly downregulated. The most upregulated gene is natriuretic peptide precursor B (NPPB) or brain natriuretic peptide, which is increased by 7-, 27-, and 197-fold at 12, 24, and 48 h, respectively. The second most upregulated gene is ATF3, which is increased by 23-fold at the 48 h timepoint. PAGE4 and IGFBP5 are the two most downregulated genes, with a 17-fold reduction in both genes. The expression of several genes (DDIT4, PDGFRA, LRP8, IGFBP5) and western blotting data on key signaling proteins indicate that compound #32 significantly inhibits the PI3K-AKT-mTOR pathway, an intracellular signaling pathway critical in cell proliferation and apoptosis.

Association of genetic variation in the natriuretic peptide system and left ventricular mass and blood pressure in newborns.

The natriuretic peptides play a key role in the modulation of left ventricular mass (LVM) and blood pressure (BP). We hypothesised that NPPA (natriuretic peptide precursor A gene), NPPB (natriuretic peptide precursor B gene), and NPPC (natriuretic peptide precursor C gene) are candidate genes possibly involved in the development or modulation of LVM at early life. To assess the relationship between NPPA, NPPB, and NPPC gene polymorphisms with LVM and BP in newborns. A total of 206 healthy newborns were studied by two-dimensional M-mode echocardiography. The polymorphisms NPPA rs5065, NPPB rs198389, and NPPC rs5268 were characterised. Newborns carrying the C allele of the NPPB polymorphism had significantly lower LVM/body surface area (BSA) and LVM/body weight (BW) values when compared with newborns' homozygotes for the T allele (41.76 g/m2 vs. 48.31 g/m2, p adjusted = 0.044 and 2.78 g/kg vs. 3.26 g/kg, p adjusted = 0.031, respectively). An association was observed between NPPA genotype and systolic BP, diastolic BP, and mean arterial pressure ≥ 90th percentile (p = 0.029, p = 0.0048, p = 0.004, respectively). Also an association was observed for systolic BP ≥ 90th percentile for NPPB (p = 0.016). The present study shows that the NPPB gene polymorphism is associated with modulation of LVM in newborns. The NPPA and NPPB gene polymorphisms are associated with BP.

Correlation between the NPPB gene promoter c.-1298 G/T polymorphism site and pulse pressure in the Chinese Han population.

The aim of this study was to investigate the correlation between the natriuretic peptide precursor B (NPPB) gene single nucleotide polymorphism (SNP) c.-1298 G/T and pulse pressure (PP) of the Chinese Han population and the association between genotype and clinical indicators of hypertension. Peripheral blood was collected from 180 unrelated patients with hypertension and 540 healthy volunteers (control group), and DNA was extracted to amplify the 5'-flanking region and 2 exons of the NPPB gene by polymerase chain reaction; the fragment was sequenced after purification. The clinical data of all subjects were recorded, the distribution of the NPPB gene c.-1298 G/T polymorphism was determined, and differences in clinical indicators between the two groups were evaluated. The mean arterial pressure PP, and creatinine levels were significantly higher in the hypertension group than in the control group (P<0.05), but no other clinical indicators differed between the groups. There were no significant differences in genotype frequency and distribution of the NPPB gene c.-1298 G/T polymorphism between the hypertension group and the control group (P>0.05); in the control group, the mean PP of individuals with the SNP c.-1298 GG genotype was greater than that of individuals with the GT+TT genotype (P<0.05). In conclusion, there was no significant correlation between the NPPB gene c.-1298 G/T polymorphism and the incidence of essential hypertension in the Han population; however, the PP of the SNP c.-1298 GG genotype was greater than that of the GT+TT genotype in the control group.

Genetic Variation in the Natriuretic Peptide System, Circulating Natriuretic Peptide Levels, and Blood Pressure: An Ambulatory Blood Pressure Study

In a large collaborative study (n > 50,000), common variants in the natriuretic peptide (NP) genes were found to be associated with circulating NP levels and also with blood pressure (BP) levels based on office BP measurements (OBPMs). It is unknown if determining an individual's BP by 24-h ambulatory BP measurements (ABPMs) will influence the effect of NP gene variations on BP levels. We used rs632793 at the NPPB (NP precursor B) locus to investigate the relationship between genetically determined serum N-terminal pro-brain NP (NT-proBNP) concentrations and BP levels determined by both 24-h ABPMs and OBPMs in a population consisting of 1,397 generally healthy individuals taking no BP-lowering drugs. rs632793 was significantly correlated with serum Nt-proBNP levels (r = 0.10, P = 0.0003), and participants with the A:A genotype had lower serum Nt-proBNP levels than participants with the G:G genotype (geometric mean (95% confidence interval (CI)): 34.8 (31.5-38.4) pg/ml vs. 48.1 (41.9-55.3) pg/ml, P = 0.0002), but higher 24-h ambulatory BP levels (mean difference (95% CI): 2.0 (0.1-4.1) mm Hg, P = 0.043, for systolic BP and 1.7 (0.4-3.1) mm Hg, P = 0.011, for diastolic BP). Office BP decreased across the genotypes from A:A to G:G, but the differences did not reach statistical significance (P ≥ 0.12). This study suggests that 24-h ABPMs is a better method than OBPMs to detect significant differences in BP levels related to genetic variance and provides further evidence that the NP system plays an important role in BP regulation.

Impact of a novel mutation in the 5′-flanking region of natriuretic peptide precursor B gene on the antihypertensive effects of sodium nitroprusside in patients with hypertension

Our aim was to identify the possible mutations of the natriuretic peptide precursor B (NPPB) gene in a family with hereditary hypertension, and determine whether the mutations are associated with the antihypertensive effect of sodium nitroprusside. The subjects included one family with hereditary hypertension, 36 cases of sporadic hypertension and 120 healthy controls. The 5'-flanking sequence of NPPB was amplified with PCR, and the presence of mutations was analyzed by direct sequencing. Patients with hypertension were treated with sodium nitroprusside and blood pressure data and serum B-type natriuretic peptide (BNP) levels were measured. A novel complex mutation in 5'-flanking sequence of the NPPB gene was detected in three patients (II 2, III 2, and III 5) of the hypertension family, which included c.-1195_ -1176 insert 5'-CCTTCTTTCTTTCTTTCTTT-3', c.-1208 T>A, c.-1214 T>C, and c.-1216 T>A. Patients with this mutation were less sensitive to sodium nitroprusside treatment. Sporadic hypertension patients (without NPPB gene mutation) and patients with the c.-1181 T>A point mutation were sensitive to sodium nitroprusside treatment. BNP levels of patients with the complex mutation were significantly lower than that of sporadic hypertension patients and c.-1181 T>A mutation patients before and during the early stage of sodium nitroprusside treatment. The complex mutation of the NPPB gene might be an etiological factor of hereditary malignant hypertension, and it is associated with low sensitivity to the antihypertensive effect of sodium nitroprusside.

Time-course Transcriptional Profiling of Human Amniotic Fluid-derived Stem Cells Using Microarray

To maintain the homeostasis of stem cells and prevent their ability to initiate tumorigenesis, it is important to identify and modify factors that prevent or accelerate stem cell senescence. We used microarrays to attempt to identify such factors in human amniotic fluid (HAF)-derived stem cells. To identify gene expression changes over a time course, we compared gene expression profiles of HAF-derived stem cells in different passages (1(st), 2(nd), 4(th), 6(th), 8(th), and 10(th)) using a Sentrix Human illumina microarray. Of the 25,804 genes in the microarray chip, 1,970 showed an over 2-fold change relative to the control (the 1(st) passage)-either upregulated or downregulated. Quantitative real-time PCR validated the microarray data for selected genes: markedly increased genes were CXCL12, cadherin 6 (CDH6), and folate receptor 3 (FOLR3). Downregulated genes included cyclin D2, keratin 8, insulin-like growth factor 2 (IGF2), natriuretic peptide precursor B (NPPB) and cellular retinoic acid binding protein 2 (CRABP2). The expression pattern of the selected genes was consistent with the microarray data except for CXCL12 and IGF2. Interestingly, the expression of NPPB was dramatically downregulated along the time course; it was almost completely shut-down by the 10(th) passage. In contrast, FOLR3 mRNA expression was dramatically increased. Taken together, although a function for NPPB and FOLR3 in stem cell senescence has not been reported, our results strongly suggest that NPPB and/or FOLR3 play a significant role in the regulation of stem cell senescence.

Clinical Significance of Pro-B-Type Natriuretic Peptide Glycosylation and Processing

Since the principal discovery of the cardiac natriuretic peptide hormones about 25 years ago, a large amount of research has identified 2 peptides derived from pro-B-type natriuretic peptide (proBNP),1 BNP and N-terminal-proBNP (NT-proBNP), as useful plasma markers in cases of heart failure (HF) and other cardiac diseases. Our present understanding of proBNP processing and the structural biochemistry and metabolism of circulating proBNP-derived peptides, by contrast, are still far from complete. In particular, posttranslational maturation and metabolism are still poorly characterized. In this issue of Clinical Chemistry , Semenov et al. describe important results that may substantially improve our current understanding of the regulation of proBNP processing (1). Like many other hormones, BNP is derived from a prohormone. The precursor proBNP hormone is encoded by a separate gene, NPPB (natriuretic peptide precursor B), which has been assigned to chromosome 1 in humans. Its transcription has been shown to be regulated by cardiac-specific gene regulators, such as GATA, the muscle-CAT binding site, and activating protein 1/cyclic adenosine monophosphate response element-like elements (2). These cis elements have since been found to be the molecular targets of many different clinically relevant stimuli that lead to basal and inducible regulation of the NPPB gene. Transcription of the human NPPB gene can be activated through various proinflammatory and hypertrophic stimuli, such as mechanical stretch, ischemic injury/hypoxia, endothelin-1, angiotensin II, interleukins, and adrenergic agonists (2). The 5′ flanking region of the NPPB gene contains acute-phase regulatory elements, and the expression of this gene is induced with the rapid kinetics of an early- response gene. In contrast to A-type natriuretic peptide (ANP), it is believed that most BNP regulation is carried out during gene expression, with most BNP being synthesized in bursts of activation from physiological and pathophysiological stimuli, when peptide secretion occurs. Only limited amounts of …

In vitro–targeted gene identification in patients with hepatitis C using a genome-wide microarray technology #

Iron in association with reactive oxygen species (ROS) is highly toxic, aggravating oxidative stress reactions. Increased iron not only plays an important role in the progression of hereditary hemochromatosis (HH) but also in common liver diseases such as chronic hepatitis C. The underlying mechanisms of hepatitis C virus (HCV)-mediated iron accumulation, however, are poorly understood. We introduce an in vitro-targeted approach to identify ROS/iron-regulated genes in patients with HCV using a genome-wide DNA microarray. The sensitivity of the 32,231 complementary DNA clone-carrying microarray was approximately 20% as estimated by detecting target genes of the genome-wide transcription factor hypoxia inducible factor 1alpha. Upon in vitro challenge to iron and oxidative stress, 265 iron-related and 1326 ROS-related genes could be identified in HepG2 cells; 233 significantly regulated genes were found in patients with mild (HCV) or severe (HH) iron deposition. Notably, 17 of the in vitro-selected genes corresponded to the genes identified in patients with HCV or HH. Among them, natriuretic peptide precursor B (NPPB) was the only iron-regulated gene identified in vitro that was differentially regulated between HCV and HH. Reverse-transcription polymerase chain reaction confirmed most of the microarray-identified genes in an even larger group of patients (n = 12). In patients with HCV, these included genes that are associated with RNA processing (MED9/NFAT, NSUN2), proliferation, differentiation, hypoxia, or iron metabolism (ISG20, MIG6, HIG2, CA9, NDRG1), whereas none of the nine known iron-related genes showed significant differences between HCV and HH. Although high-density microarray technology is less suitable for routine liver diagnosis, its use in combination with prior in vitro selection is a powerful approach to identify candidate genes relevant for liver disease.

Linkage disequilibrium analyses of natriuretic peptide precursor B locus reveal risk haplotype conferring high plasma BNP levels

Background. Brain natriuretic peptide (BNP) has been widely used for the diagnosis and prognostic evaluation of chronic heart failure (CHF). In the present study, we performed association study of single nucleotide polymorphisms (SNPs) surrounding the natriuretic peptide precursor B (NPPB) gene with plasma BNP levels in 2970 adult Japanese. Methods and Results. Association analysis between SNPs of the NPPB gene and plasma BNP revealed significant associations of the 8 SNPs surrounding the entire NPPB gene with plasma BNP levels. For instance, as to SNP rs198389 (T−381C), plasma BNP levels among the three genotypic categories, i.e., 2189 homozygous T-allele carriers (BNP 26.4 ± 0.6 pg/ml), 697 heterozygous carriers (35.0 ± 1.1 pg/ml), and 52 homozygous C-allele carriers (46.0 ± 4.1 pg/ml) indicated a co-dominant effect of the minor C-allele on elevating plasma BNP levels ( P < 0.0001). Linkage disequilibrium (LD) analysis among the 8 SNPs revealed that the region consisted of two, 5′ major and 3′ minor, LD blocks. Haplotype-based association analysis demonstrated that plasma BNP levels were associated closely with the haplotypes-1 and -2 of the major LD block. Conclusion. These results suggest that genetic variation at the primary locus NPPB gene, represented by definition of risk haplotypes, may be an important determinant of plasma BNP levels.

A Novel Variable Number of Tandem Repeat of the Natriuretic Peptide Precursor B gene's 5'-Flanking Region is Associated with Essential Hypertension among Japanese Females

Brain natriuretic peptide (BNP) acts primarily as a cardiac hormone; it is produced by the ventricle and has both vasodilatory and natriuretic actions. Therefore, the BNP gene is thought to be a candidate gene for essential hypertension (EH). The present study identified variants in the 5'-flanking region of natriuretic peptide precursor B (NPPB) gene and assessed the relationship between gene variants and EH. The polymerase chain reaction-single strand conformation polymorphism method and nucleotide sequencing were used to identify variants. A novel variable number of tandem repeat (VNTR) polymorphism in the 5'-flanking region (-1241 nucleotides from the major transcriptional initiation site) was discovered. This VNTR polymorphism is a tandem repeat of the 4-nucleotide sequence TTTC. There were 8 alleles, ranging from 9-repeat to 19-repeat. An association study was done involving 317 EH patients and 262 age-matched normotensive (NT) subjects. The 11-repeat allele was the most frequent (88.2%); the 16-repeat allele was the second most frequent (10.5%) in the NT group. The observed and expected genotypes were in agreement with the predicted Hardy-Weinberg equilibrium values (P=0.972). Among females, the overall distribution of genotypes was significantly different between the EH and NT groups (p=0.039). The frequency of the 16-repeat allele was significantly lower in the female EH group (6.5%) than in the female NT group (12.2%, p=0.046). The 16-repeat allele of the VNTR in the 5'-flanking region of NPPB appears to be a useful genetic marker of EH in females.

Localization of the human B-type natriuretic peptide precursor (NPPB) gene to chromosome 1p36

Cardiac myocytes synthesize and secrete a family of peptide hormones with potent natriuretic, diuretic, and vasodilatory properties. These peptides are derived from precursor molecules that are encoded by two different genes, the atrial natriuretic peptide precursor A (NPPA) and the B-type natriuretic peptide or natriuretic peptide precursor B (NPPB). A human genomic clone for the NPPB gene was used to determine the chromosomal location of the NPPB gene. Analysis of Southern blot hybridization to DNAs from various somatic cell hybrids and fluorescence in situ hybridization allowed assignment of the NPPB locus to human chromosome 1p36. This location coincided with that of the NPPA locus; pulsed-field gel electrophoresis placed NPPA and NPPB within 50 kb of each other. This close chromosomal linkage, together with the conserved primary sequences and structural organization of the two natriuretic peptide precursor genes, suggests that the natriuretic peptide loci may have evolved from a common ancestor gene.