ANGPTL4 variants E40K and T266M are associated with lower fasting triglyceride levels in Non-Hispanic White Americans from the Look AHEAD Clinical Trial

<p>Abstract</p> <p>Background</p> <p>Elevated triglyceride levels are a risk factor for cardiovascular disease. Angiopoietin-like protein 4 (Angptl4) is a metabolic factor that raises plasma triglyceride levels by inhibiting lipoprotein lipase (LPL). In non-diabetic individuals, the <it>ANGPTL4 </it>coding variant E40K has been associated with lower plasma triglyceride levels while the T266M variant has been associated with more modest effects on triglyceride metabolism. The objective of this study was to determine whether ANGPTL4 E40K and T266M are associated with triglyceride levels in the setting of obesity and T2D, and whether modification of triglyceride levels by these genetic variants is altered by a lifestyle intervention designed to treat T2D.</p> <p>Methods</p> <p>The association of <it>ANGPTL4 </it>E40K and T266M with fasting triglyceride levels was investigated in 2,601 participants from the Look AHEAD Clinical Trial, all of whom had T2D and were at least overweight. Further, we tested for an interaction between genotype and treatment effects on triglyceride levels.</p> <p>Results</p> <p>Among non-Hispanic White Look AHEAD participants, <it>ANGPTL4 </it>K40 carriers had mean triglyceride levels of 1.61 ± 0.62 mmol/L, 0.33 mmol/L lower than E40 homozygotes (p = 0.001). Individuals homozygous for the minor M266 allele (MAF 30%) had triglyceride levels of 1.75 ± 0.58 mmol/L, 0.24 mmol/L lower than T266 homozygotes (p = 0.002). The association of the M266 with triglycerides remained significant even after removing K40 carriers from the analysis (p = 0.002). There was no interaction between the weight loss intervention and genotype on triglyceride levels.</p> <p>Conclusions</p> <p>This is the first study to demonstrate that the <it>ANGPTL4 </it>E40K and T266M variants are associated with lower triglyceride levels in the setting of T2D. In addition, our findings demonstrate that <it>ANGPTL4 </it>genotype status does not alter triglyceride response to a lifestyle intervention in the Look AHEAD study.</p

<it>Little ROCK </it>is a <it>ROCK1 </it>pseudogene expressed in human smooth muscle cells

Abstract Background Sequencing of the human genome has identified numerous chromosome copy number additions and subtractions that include stable partial gene duplications and pseudogenes that when not properly annotated can interfere with genetic analysis. As an example of this problem, an evolutionary chromosome event in the primate ancestral chromosome 18 produced a partial duplication and inversion of rho-associated protein kinase 1 (ROCK1 -18q11.1, 33 exons) in the subtelomeric region of the p arm of chromosome 18 detectable only in humans. ROCK1 and the partial gene copy, which the gene databases also currently call ROCK1, include non-unique single nucleotide polymorphisms (SNPs). Results Here, we characterize this partial gene copy of the human ROCK1, termed Little ROCK, located at 18p11.32. Little ROCK includes five exons, four of which share 99% identity with the terminal four exons of ROCK1 and one of which is unique to Little ROCK. In human while ROCK1 is expressed in many organs, Little ROCK expression is restricted to vascular smooth muscle cell (VSMC) lines and organs rich in smooth muscle. The single nucleotide polymorphism database (dbSNP) lists multiple variants contained in the region shared by ROCK1 and Little ROCK. Using gene and cDNA sequence analysis we clarified the origins of two non-synonymous SNPs annotated in the genome to actually be fixed differences between the ROCK1 and the Little ROCK gene sequences. Two additional coding SNPs were valid polymorphisms selectively within Little ROCK. Little ROCK-Green Fluorescent fusion proteins were highly unstable and degraded by the ubiquitin-proteasome system in vitro. Conclusion In this report we have characterized Little ROCK (ROCK1P1), a human expressed pseudogene derived from partial duplication of ROCK1. The large number of pseudogenes in the human genome creates significant genetic diversity. Our findings emphasize the importance of taking into consideration pseudogenes in all candidate gene and genome-wide association studies, as well as the need for complete annotation of human pseudogenome.</p

The Mu-Opioid Receptor Variant N190K is Unresponsive to Peptide Agonists Yet Can be Rescued by Small Molecule Drugs MOL #64188 2 Running Title: Small molecules rescue function of an inactive MOR variant

MOL #64188 3 Abstract The mu-opioid receptor (MOR) plays an important role in modulating analgesia, feeding behavior and a range of autonomic functions. In the current study, we investigated the degree to which thirteen naturally-occurring missense mutations affect the pharmacological properties of the human MOR. Following expression of each receptor in HEK293 cells, signaling (Gα i/omediated) induced by peptide agonists was assessed utilizing luciferase reporter gene assays. Multiple mutants (S66F, S147C, R260H, R265C, R265H and S268P) show a significant reduction in agonist potency. At the N190K variant, agonist-mediated signaling was essentially absent. ELISA, microscopic analysis and radioligand binding assays revealed that this mutant shows markedly reduced cell surface expression, whereas all other receptor variants were expressed at normal levels. Surface expression of the N190K variant could be increased by incubation with the alkaloid agonist buprenorphine, or with either of the structurally related MOR antagonists, naltrexone or naloxone. Surprisingly, both putative antagonists, despite being inactive at the wild type MOR, triggered a concentration-dependent increase in N190K receptor mediated signaling. In contrast, peptidic ligands failed to promote expression or rescue function of the N190K mutant. Subsequent analysis of the N190K variant in an ethnically diverse cohort identified this isoform in a subgroup of African Americans. Taken together, our studies reveal that the N190K mutation leads to severe functional alterations and, in parallel, changes the response to established MOR ligands. The extent to which this mutation results in physiological abnormalities or affects drug sensitivity in selected populations (e.g. those with chronic pain or addiction) remains to be investigated

Use of Liraglutide in the Real World and Impact at 36 Months on Metabolic Control, Weight, Lipid Profile, Blood Pressure, Heart Rate, and Renal Function

PURPOSE: An observational retrospective study was conducted by 2 diabetes clinics in Italy to assess patterns of use and long-term effectiveness of liraglutide on established and emerging parameters. METHODS: Data from 261 patients with type 2 diabetes who started treatment with liraglutide between 2010 and 2014 were collected. Hierarchical linear regression models were applied to assess trends over time of clinical parameters. Factors associated with higher likelihood of dropout were identified through multivariate logistic analysis. FINDINGS: Liraglutide was initiated as a switch in 42.5% of patients and as an add-on in 49.8%; in 7.7% of the patients initiation of liraglutide was associated with a reduction in the number of pharmacologic agents. A statistically significant reduction after 36 months was found for the following parameters (mean change [95% CIs]): glycosylated hemoglobin (HbA1c; -1.01% [1.34% to -0.68%]), fasting blood glucose (-27.5 [-40.6 to -14.4] mg/dL), weight (-2.9 [-4.5 to -1.3] kg), body mass index (-1.13 [-1.76 to -0.50] kg/m2), waist circumference (-1.74 [-3.85 to -0.37] cm), and LDL-C (-24.7 [-36.67 to -12.8] mg/dL). Improvements in systolic (-3.5 mm Hg) and diastolic (-2.3 mm Hg) blood pressures were observed at 24 months. Albuminuria was reduced by -16.6 mg/L during 36 months, although statistical significance was not reached. Glomerular filtration rate and heart rate were unchanged. Reductions in HbA1c between -0.6% and -1.3% were obtained in specific subgroups. Treatment was effective also in patients with >20 years of diabetes duration, although the likelihood of dropout was 6% higher for each additional year of disease duration (RR = 1.06; 95% CI, 1.01-1.12). The likelihood of dropout was almost four times higher for subjects treated with insulin (RR = 3.82; 95% CI, 1.22-11.96) and more than twice for those treated with sulfonylureas (RR = 2.39; 95% CI, 1.16-4.94) compared with patients not treated with these agents. IMPLICATIONS: Liraglutide used in routine clinical conditions maintains its effectiveness on metabolic control and weight after 3 years. Improvements in terms of metabolic control were found when liraglutide was used as both switch and add-on treatment. In addition, improvements were sustained when liraglutide replaced sulfonylureas or insulin. Diabetes duration had no impact on drug efficacy. Long-term benefits relative to blood pressure and LDL-C were also found, which could not be entirely explained by antihypertensive/lipid-lowering treatment intensification. No major effect on renal parameters was documented. Diabetes duration and some concomitant treatments were associated with a higher likelihood of liraglutide discontinuation. These data can contribute to improve appropriateness and cost-effectiveness profile of liraglutide

Application of gene network analysis techniques identifies AXIN1/PDIA2 and endoglin haplotypes associated with bicuspid aortic valve.

Bicuspid Aortic Valve (BAV) is a highly heritable congenital heart defect. The low frequency of BAV (1% of general population) limits our ability to perform genome-wide association studies. We present the application of four a priori SNP selection techniques, reducing the multiple-testing penalty by restricting analysis to SNPs relevant to BAV in a genome-wide SNP dataset from a cohort of 68 BAV probands and 830 control subjects. Two knowledge-based approaches, CANDID and STRING, were used to systematically identify BAV genes, and their SNPs, from the published literature, microarray expression studies and a genome scan. We additionally tested Functionally Interpolating SNPs (fitSNPs) present on the array; the fourth consisted of SNPs selected by Random Forests, a machine learning approach. These approaches reduced the multiple testing penalty by lowering the fraction of the genome probed to 0.19% of the total, while increasing the likelihood of studying SNPs within relevant BAV genes and pathways. Three loci were identified by CANDID, STRING, and fitSNPS. A haplotype within the AXIN1-PDIA2 locus (p-value of 2.926x10(-06)) and a haplotype within the Endoglin gene (p-value of 5.881x10(-04)) were found to be strongly associated with BAV. The Random Forests approach identified a SNP on chromosome 3 in association with BAV (p-value 5.061x10(-06)). The results presented here support an important role for genetic variants in BAV and provide support for additional studies in well-powered cohorts. Further, these studies demonstrate that leveraging existing expression and genomic data in the context of GWAS studies can identify biologically relevant genes and pathways associated with a congenital heart defect

Deciphering the Role of Wnt and Rho Signaling Pathway in iPSC-Derived ARVC Cardiomyocytes by In Silico Mathematical Modeling

Arrhythmogenic Right Ventricular cardiomyopathy (ARVC) is an inherited cardiac muscle disease linked to genetic deficiency in components of the desmosomes. The disease is characterized by progressive fibro-fatty replacement of the right ventricle, which acts as a substrate for arrhythmias and sudden cardiac death. The molecular mechanisms underpinning ARVC are largely unknown. Here we propose a mathematical model for investigating the molecular dynamics underlying heart remodeling and the loss of cardiac myocytes identity during ARVC. Our methodology is based on three computational models: firstly, in the context of the Wnt pathway, we examined two different competition mechanisms between β-catenin and Plakoglobin (PG) and their role in the expression of adipogenic program. Secondly, we investigated the role of RhoA-ROCK pathway in ARVC pathogenesis, and thirdly we analyzed the interplay between Wnt and RhoA-ROCK pathways in the context of the ARVC phenotype. We conclude with the following remark: both Wnt/β-catenin and RhoA-ROCK pathways must be inactive for a significant increase of PPARγ expression, suggesting that a crosstalk mechanism might be responsible for mediating ARVC pathogenesis