Identification of IGF1, SLC4A4, WWOX, and SFMBT1 as hypertension susceptibility genes in Han Chinese with a genome-wide gene-based association study

Hypertension is a complex disorder with high prevalence rates all over the world. We conducted the first genome-wide gene-based association scan for hypertension in a Han Chinese population. By analyzing genome-wide single-nucleotide-polymorphism data of 400 matched pairs of young-onset hypertensive patients and normotensive controls genotyped with the Illumina HumanHap550-Duo BeadChip, 100 susceptibility genes for hypertension were identified and also validated with permutation tests. Seventeen of the 100 genes exhibited differential allelic and expression distributions between patient and control groups. These genes provided a good molecular signature for classifying hypertensive patients and normotensive controls. Among the 17 genes, IGF1, SLC4A4, WWOX, and SFMBT1 were not only identified by our gene-based association scan and gene expression analysis but were also replicated by a gene-based association analysis of the Hong Kong Hypertension Study. Moreover, cis-acting expression quantitative trait loci associated with the differentially expressed genes were found and linked to hypertension. IGF1, which encodes insulin-like growth factor 1, is associated with cardiovascular disorders, metabolic syndrome, decreased body weight/size, and changes of insulin levels in mice. SLC4A4, which encodes the electrogenic sodium bicarbonate cotransporter 1, is associated with decreased body weight/size and abnormal ion homeostasis in mice. WWOX, which encodes the WW domain-containing protein, is related to hypoglycemia and hyperphosphatemia. SFMBT1, which encodes the scm-like with four MBT domains protein 1, is a novel hypertension gene. GRB14, TMEM56 and KIAA1797 exhibited highly significant differential allelic and expressed distributions between hypertensive patients and normotensive controls. GRB14 was also found relevant to blood pressure in a previous genetic association study in East Asian populations. TMEM56 and KIAA1797 may be specific to Taiwanese populations, because they were not validated by the two replication studies. Identification of these genes enriches the collection of hypertension susceptibility genes, thereby shedding light on the etiology of hypertension in Han Chinese populations.     

Placenta proteome analysis from Down syndrome pregnancies for biomarker discovery

Down syndrome is one of the most frequent chromosomal disorders, with a prevalence of approximately 1/500 to 1/800, depending on the maternal age distribution of the pregnant population. However, few reliable protein biomarkers have been used in the diagnosis of this disease. Recent progress in quantitative proteomics has offered opportunities to discover biomarkers for tracking the progression and for understanding the molecular mechanisms of Down syndrome. In the present study, placental samples were analyzed by fluorescence two-dimensional differential gel electrophoresis (2D-DIGE) and differentially expressed proteins were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In total, 101 proteins have been firmly identified representing 80 unique gene products. These proteins mainly function in cytoskeleton structure and regulation (such as vimentin and Profilin-1). Additionally, our quantitative proteomics approach has identified numerous previously reported Down syndrome markers, such as myelin protein. Here we present several Down syndrome biomarkers including galectin-1, ataxin-3 and sprouty-related EVH1 domain-containing protein 2 (SPRED2), which have not been reported elsewhere and may be associated with the progression and development of the disease. In summary, we report a comprehensive placenta-based proteomics approach for the identification of potential biomarkers for Down syndrome, in which serum amyloid P-component (APCS) and ataxin-3 have been shown to be up-regulated in the maternal peripheral plasma of Down syndrome cases. The potential of utilizing these markers for the prognosis and screening of Down syndrome warrants further investigation.     

A benefit-finding intervention for family caregivers of persons with Alzheimer disease: study protocol of a randomized controlled trial

Background

Patients with ST-elevation myocardial infarction (STEMI) not treated with primary or rescue percutaneous coronary intervention (PCI) are at risk for recurrent ischemia, especially when viability in the infarct-area is present. Therefore, an invasive strategy with PCI of the infarct-related coronary artery in patients with viability would reduce the occurrence of a composite end point of death, reinfarction, or unstable angina (UA).

Methods

Patients admitted with an (sub)acute myocardial infarction, who were not treated by primary or rescue PCI, and who were stable during the first 48 hours after the acute event, were screened for the study. Eventually, we randomly assigned 216 patients with viability (demonstrated with low-dose dobutamine echocardiography) to an invasive or a conservative strategy. In the invasive strategy stenting of the infarct-related coronary artery was intended with abciximab as adjunct treatment. Seventy-five (75) patients without viability served as registry group. The primary endpoint was the composite of death from any cause, recurrent myocardial infarction (MI) and unstable angina at one year. As secondary endpoint the need for (repeat) revascularization procedures and anginal status were recorded.

Results

The primary combined endpoint of death, recurrent MI and unstable angina was 7.5% (8/106) in the invasive group and 17.3% (19/110) in the conservative group (Hazard ratio 0.42; 95% confidence interval [CI] 0.18-0.96; p = 0.032). During follow up revascularization-procedures were performed in 6.6% (7/106) in the invasive group and 31.8% (35/110) in the conservative group (Hazard ratio 0.18; 95% CI 0.13-0.43; p < 0.0001). A low rate of recurrent ischemia was found in the non-viable group (5.4%) in comparison to the viable-conservative group (14.5%). (Hazard-ratio 0.35; 95% CI 0.17-1.00; p = 0.051).

Conclusion

We demonstrated that after acute MI (treated with thrombolysis or without reperfusion therapy) patients with viability in the infarct-area benefit from a strategy of early in-hospital stenting of the infarct-related coronary artery. This treatment results in a long-term uneventful clinical course. The study confirmed the low risk of recurrent ischemia in patients without viability.

Trial registration

ClinicalTrials.gov: NCT00149591.     

Regulation of adenylyl cyclase in the central nervous system

Adenylyl cyclases (ACs) are a family of enzymes that synthesize one of the major second messengers, cAMP, upon stimulation. Since the report of the first adenylyl cyclase (AC) gene in 1989, tremendous efforts have been devoted to identifying and characterizing more AC isozymes. In the past decade, significant knowledge regarding the basic structure, tissue distribution, and regulation of AC isozymes has been accumulated. Because members of the AC superfamily are tightly controlled by various signals, one of the most important impacts of these AC isozymes is their contribution to the complexity and fine-tuning of cellular signalling, especially in the central nervous system (CNS) where multiple signals constantly occur. This review focuses on recent progress toward understanding the physiological roles of ACs in the CNS.     

Accelerated clearance of polyethylene glycol-modified proteins by anti-polyethylene glycol IgM.

Tumor therapy by the preferential activation of a prodrug at tumor cells targeted with an antibody-enzyme conjugate may allow improved treatment efficacy with reduced side effects. We examined antibody-mediated clearance of poly(ethylene glycol)-modified beta-glucuronidase (betaG-sPEG) as a method to reduce serum concentrations of enzyme and minimize systemic prodrug activation. Enzyme-linked immunosorbent assay and immunoblot analysis of two monoclonal antibodies generated by immunization of BALB/c mice with an antibody-betaG-sPEG conjugate showed that mAb 1E8 (IgG1) bound betaG and betaG-sPEG whereas mAb AGP3 (IgM) bound poly(ethylene glycol). Neither antibody affected the betaG activity. mAb 1E8 and AGP3 were modified with 36 and 208 galactose residues (1E8-36G and AGP3-208G) with retention of 72 and 48% antigen-binding activity, respectively, to target immune complexes to the asialoglycoprotein receptor on liver cells. mAb 1E8 and AGP3 cleared betaG-PEG from the circulation of mice as effectively as 1E8-36G and AGP3-208G, respectively. mAb AGP3, however, cleared betaG-sPEG more completely and rapidly than 1E8, reducing the serum concentration of betaG-sPEG by 38-fold in 8 h. AGP3 also reduced the concentration of an antibody-betaG-sPEG conjugate in blood by 280-fold in 2 h and 940-fold in 24 h. AGP3-mediated clearance did not produce obvious damage to liver, spleen, or kidney tissues. In addition, AGP3 clearance of betaG-sPEG before administration of BHAMG, a glucuronide prodrug of p-hydroxyaniline mustard, prevented toxicity associated with systemic activation of the prodrug based on mouse weight and blood cell numbers. AGP3 should be generally useful for accelerating the clearance of PEG-modified proteins as well as for improving the tumor/blood ratios of antibody-betaG-PEG conjugates for glucuronide prodrug therapy of cancer.     

Production of D-p-hydroxyphenylglycine by N-carbamoyl-D-amino acid amidohydrolase-overproducing Escherichia coli strains.

The N-carbamoyl-D-amino acid amidohydrolase (D-carbamoylase) gene from Agrobacterium radiobacter NRRL B11291 has been successfully cloned and expressed in Escherichia coli. Subcloning of the D-carbamoylase gene into different types of vectors and backgrounds of E. coli strains showed that the optimal expression level of D-carbamoylase was achieved in a ColE1-derived plasmid with a 150-fold increase in specific enzyme activity compared to that in a pSC101-derived plasmid. In addition, the recombinant plasmids were very stable in the E. coli strain ATCC11303 but not in JCL1258 tested here. Employing the recombinant E. coli strain DH5alpha/pAH61 for D-p-hydroxyphenylglycine production showed that the cell was capable of transforming N-carbamoyl-D-hydroxylphenylglycine to D-p-hydroxyphenylglycine with a molar conversion yield of 100% and a production rate of 1.9 g/(L h). In comparison with A. radiobacter NRRL B11291, this productivity approximates a 55-fold increase in D-hydroxyphenylglycine production. This result suggests the potential application of recombinant E. coli strains for the transformation reaction.     

Nucleosides VI: A Novel and Convenient Synthesis of Purine S-Cyclonucleosides Via Mitsunobu Reaction

Abstract

Two representative S-cyclonucleosides, 8,5′-anhydro-2′, 3′-O-isopropylidene-8-mercaptoadenosine (3) and 8,2′-anhydro-3′,5′-O-(tetraisopropyldisiloxane-1,3-diyl)-8-mercaptoguanosine (8), were prepared in good yields by dropwise addition of one equivalent each of triphenylphosphine and DEAD in DMF into a mixture of 2′,3′-O-isopropylidene-8-mercaptoadenosine (2) or 3′,5′-O-(tetra-iso-propyldisiloxane-1,3-diyl)-8-mercaptoguanosine (7), respectively, in DMF. Treatment of compound 2 with two equivalents each of triphenylphosphine and DEAD in DMF afforded N-[8,5′-anhydro-2′,3′-O-isopropylidene-8-mercaptopurin-6-yl]triphenylphospha-λ5-azene (4) in 87% yield.     

Enhancement of brain-type creatine kinase activity ameliorates neuronal deficits in Huntington's disease

Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin (HTT) gene. Brain-type creatine kinase (CKB) is an enzyme involved in energy homeostasis via the phosphocreatine–creatine kinase system. Although downregulation of CKB was previously reported in brains of HD mouse models and patients, such regulation and its functional consequence in HD are not fully understood. In the present study, we demonstrated that levels of CKB found in both the soma and processes were markedly reduced in primary neurons and brains of HD mice. We show for the first time that mutant HTT (mHTT) suppressed the activity of the promoter of the CKB gene, which contributes to the lowered CKB expression in HD. Exogenous expression of wild-type CKB, but not a dominant negative CKB mutant, rescued the ATP depletion, aggregate formation, impaired proteasome activity, and shortened neurites induced by mHTT. These findings suggest that negative regulation of CKB by mHTT is a key event in the pathogenesis of HD and contributes to the neuronal dysfunction associated with HD. In addition, besides dietary supplementation with the CKB substrate, strategies aimed at increasing CKB expression might lead to the development of therapeutic treatments for HD.     

Unusual conformational flexibility in N1-substituted uncommon purine nucleosides. Crystal structure of 1-allyl-isoguanosine and 1-allyl-xanthosine.

Several new N1-substituted uncommon purine nucleosides, including doridosine (1-methyl-isoguanosine; m-iG), 1-allyl-isoguanosine (a-iG) and 1-allyl-xanthosine (a-X), have been synthesized and tested as agonists for the adenosine receptors. Some have smooth muscle relaxant or negative chronotropic activities. The X-ray crystal structure of these compounds has been determined at atomic resolution in order to understand the structure-activity relationship. The structures were solved by direct methods and refined by full-matrix least-squares refinement procedure. The crystallographic parameters are: a-iG, space group P2(1), a = 10.573 (1) A, b = 21.955 (2) A, c = 14.360 (1) A, beta = 110.65 (1) degree, no. of 3 sigma Fo's = 4585, R = 0.047; a-X, space group P2(1)2(1)2(1), a = 16.015 (2) A, b = 16.239 (1) A, (1) A, c = 5.3723 (5) A, no. of 3 sigma Fo's = 1169, R = 0.031. In the a-iG crystal, there are 4 independent molecules (with different conformation) per asymmetric unit. While all 4 molecules adopt anti chi CN glycosyl torsion angle, their riboses have 3 distinct puckers (C2'-exo, C2'-endo and C1'-exo). In contrast, the a-X structure adopts a syn chi CN glycosyl torsion angle, which is stabilized by an intramolecular hydrogen bond between the N3 of purine base and the O5' of the ribose (in C2'-endo pucker). Both purine bases (a-iG and a-X) are mainly in the keto tautomer form. For the isoguanine base, the averaged N1-C2 bond distance (1.42 A) is significantly longer than that (1.375 A) of the guanine base. For the xanthine base, N3 nitrogen has an imino proton attached which is unambiguously located in the electron density map. The surprising flexibility in the ribose ring of these N1-substituted uncommon purine nucleosides suggests that the ribose moiety may not participate in the binding of nucleoside to the adenosine receptors.