No abstract

Environmental factors shared by co-twins affect BMI in childhood, but little evidence for their contribution was found in late adolescence. Our results suggest that genetic factors play a major role in the variation of BMI in adolescence among populations of different ethnicities exposed to different environmental factors related to obesity.

Objective: Serum-and glucocorticoid-inducible kinase 1 (SGK1) inhibits the ubiquitin ligase neuronal cell expressed developmentally downregulated 4-2 (Nedd4-2), which retards the retrieval of the epithelial Na ϩ channel ENaC. Accordingly, SGK1 enhances ENaC abundance in the cell membrane. The significance of this effect is shown by an association of an E8CC/CT;I6CC polymorphism in the SGK1 gene with increased blood pressure. However, strong expression of SGK1 in enterocytes not expressing ENaC points to further functions of SGK1. This study was performed to test for regulation of Na ϩ -coupled glucose transporter 1 (SGLT1) by Nedd4-2, SGK1, and/or the related kinases SGK3 and PKB. Additional studies searched for an association of the SGK1 gene with BMI. Research Methods and Procedures: mRNA encoding SGLT1, wild-type Nedd4-2, inactive C938S Nedd4-2, wild type SGK1, constitutively active S422D SGK1 or inactive K127N SGK1, wild-type SGK3, and constitutively active T308DS473D PKB or inactive T308AS473A PKB were injected into Xenopus oocytes, and glucose transport was quantified from glucose-induced current (I glc ). BMI was determined in individuals with or without the E8CC/CT;I6CC polymorphism. Results: I glc was significantly decreased by coexpression of Nedd4-2 but not of C938S Nedd4-2. Coexpression of SGK1, S422D SGK1, SGK3, or T308DS473D PKB, but not of K127N SGK1 or T308AS473A PKB, enhanced I glc and reversed the effect of Nedd4-2. SGK1 and SGK3 phosphorylated Nedd4-2. Deletion of the SGK/PKB phosphorylation sites in Nedd4-2 blunted the kinase effects. BMI was significantly (p Ͻ 0.008) greater in individuals with the E8CC/CT;I6CC polymorphism than in individuals without. Discussion: Overactivity of SGK1 may lead not only to excessive ENaC activity and hypertension but also to enhanced SGLT1 activity and obesity.

All Mendelian hypertension syndromes described to date involve increased sodium reabsorption in the distal nephron. 5 The sole exception is autosomal-dominant hypertension with BDE (HTNB, OMIM #112410), first reported in a Turkish kindred. 2,6 HTNB was linked to chromosome 12p in six unrelated families. 2,7,8 The locus accounts for a ~50 mm Hg mean blood pressure difference at age 50 years. 2 The penetrance is 100% (Fig. 1a). Previously, we reported a rearrangement on chromosome 12p common to all families. 8,9 A linkage study in Chinese hypertensive families without BDE coincided with the HTNB locus, supporting relevance to essential hypertension. 10 Whole-genome sequencing of Turkish family members revealed a heterozygous missense mutation in PDE3A (Gene ID: 5139), a gene encoding a cGMP/cAMP phosphodiesterase with a prominent role in the heart, VSMC, oocytes and platelets. 11 Resequencing of all 48 affected persons in six unrelated families identified six independently clustered heterozygous missense mutations in exon 4 (Fig. 1a, b Supplementary Fig. 1).We detected none of the previously described chromosomal breakpoints on chromosome 12p12.2-12.1, perhaps due to high repetitive content in the breakpoint regions Fig. 2a-c). 4 A haplotype analysis identified a novel recombination that reduced the linkage interval and eliminated an inversion common to all affected individuals in the six families (Fig. 2c). 9 In contrast, the affected mother's haplotype showed co-segregation with the more severe brachydactyly phenotype.PDEs are involved during early stages of osteogenesis. 12 PDE4D mutations have been associated with severe brachydactyly in acrodysostosis. 13,14 In mice, Pde3a was expressed in the developing limbs, consistent with a role during chondrogenesis (Fig. 2d, Supplementary Fig. 3a, b). Chondrogenic downregulation of PTHLH encoding PTHrP was associated with BDE. 15 We also observed PTHLH downregulation in chondrogenically induced fibroblasts from affected persons (Fig. 2e, Supplementary Fig. 3c).We addressed the functional consequences of the identified PDE3A mutations in HeLa cells expressing the six mutations. Forskolin or L-arginine stimulated the adenylate or guanylate cyclases to enhance cellular cAMP or cGMP levels, respectively. 16,17 We detected significantly reduced cAMP levels, consistent with gain-of-function mutations with no change in cGMP levels for the PDE3A mutations ( Supplementary Fig. 4a, b). Three PDE3A isoforms, PDE3A1 (microsomal), PDE3A2 and PDE3A3 (microsomal and cytosolic), have been identified in human myocardium. 18,19 PDE3A3 does not contain the sequence harboring the detected mutations. The predominant isoform in VSMC is PDE3A2. 18,20 To directly elucidate the mutations' effects, we compared the Michaelis-Menten kinetics of cAMPhydrolytic activity for recombinant T445N FLAG-tagged PDE3A1 and PDE3A1-WT and the tagged A2 isoforms purified from transfected cells (Fig. 3a, b, Supplementary Fig. 4d-k). The T445N mutation increased the affinity of both enzyme's isoforms for cAM...

Height variation is known to be determined by both genetic and environmental factors, but a systematic description of how their influences differ by sex, age and global regions is lacking. We conducted an individual-based pooled analysis of 45 twin cohorts from 20 countries, including 180,520 paired measurements at ages 1–19 years. The proportion of height variation explained by shared environmental factors was greatest in early childhood, but these effects remained present until early adulthood. Accordingly, the relative genetic contribution increased with age and was greatest in adolescence (up to 0.83 in boys and 0.76 in girls). Comparing geographic-cultural regions (Europe, North-America and Australia, and East-Asia), genetic variance was greatest in North-America and Australia and lowest in East-Asia, but the relative proportion of genetic variation was roughly similar across these regions. Our findings provide further insights into height variation during childhood and adolescence in populations representing different ethnicities and exposed to different environments.

As confirmed in modeling studies, these changes are expected to shorten action potential duration by an increase in I(Kr). This recapitulates the shorter QTc in females homozygous for the 2690C-allele.

Abstract. Isolated human neutrophils exhibit a bimodal membrane proteinase 3 (PR3) expression. PR3 is the main target antigen in Wegener granulomatosis (WG). Cells with low expression can be easily distinguished from cell subsets with high expression. In a recent study, a large neutrophil subset expressing membrane PR3 (mPR3 ϩ ) was a risk factor for systemic ANCA-associated vasculitis. PR3 membrane expression patterns are quite stable in a given individual, raising the possibility of genetic variance. The aims of this study were: (1) to investigate the association of mPR3 expression and the risk of WG in an independent German cohort; (2) to test the hypothesis that mPR3 expression on neutrophils is genetically influenced; and (3) to investigate whether or not mPR3 expression is a function of intracellular PR3 content. mPR3 expression was assessed by FACS analysis in isolated human neutrophils. Neutrophil mPR3 expression was studied in 35 patients with WG, 15 patients with other inflammatory diseases, 125 healthy volunteers, and 27 (15 monozygotic and 12 dizygotic) pairs of twins. The intracellular PR3 content was assessed by intracellular flow cytometry and by Western blotting after separating mPR3 low and high expressing cells by FACSort. FACS analysis in a subset of 16 healthy subjects showed a highly conserved PR3 phenotype in two independent investigations Ͼ12 mo apart (r ϭ 0.937). Patients with WG demonstrated a significantly higher percentage of mPR3 ϩ neutrophils than healthy controls and patients with other inflammatory diseases. The mPR3 ϩ percentage was highly correlated in MZ twins (r ϭ 0.99) compared with DZ twins (r ϭ 0.06). The intracellular PR3 content was not different in persons with low or high mPR3 expression, nor was the PR3 content different in cells with low or high mPR3 expression within a given individual. These data indicate that WG patients have a higher percentage of mPR3-expressing neutrophils. Furthermore, mPR3 expression is influenced by genetic variance. Finally, mPR3 expression is independent of intracellular PR3 content. kettritz@frk-berlin.de

Abstract-The armadillo-related protein ␤-catenin has multiple functions in cardiac tissue homeostasis: stabilization of ␤-catenin has been implicated in adult cardiac hypertrophy, and downregulation initiates heart formation in embryogenesis. The protein is also part of the cadherin/catenin complex at the cell membrane, where depletion might result in disturbed cell-cell interaction similar to N-cadherin knockout models. Here, we analyzed the in vivo role of ␤-catenin in adult cardiac hypertrophy initiated by angiotensin II (Ang II). The cardiac-specific mifepristone-inducible ␣MHC-CrePR1 transgene was used to induce ␤-catenin depletion (loxP-flanked exons 3 to 6, ␤-cat ⌬ex3-6 mice) or stabilization (loxP-flanked exon 3, ␤-cat ⌬ex3 mice). Levels of ␤-catenin were altered both in membrane and nuclear extracts. Analysis of the ␤-catenin target genes Axin2 and Tcf-4 confirmed increased ␤-catenin-dependent transcription in ␤-catenin stabilized mice. In both models, transgenic mice were viable and healthy at age 6 months. ␤-Catenin appeared dispensable for cell membrane function. Ang II infusion induced cardiac hypertrophy both in wild-type mice and in mice with ␤-catenin depletion. In contrast, mice with stabilized ␤-catenin had decreased cross-sectional area at baseline and an abrogated hypertrophic response to Ang II infusion. Stabilizing ␤-catenin led to impaired fractional shortening compared with control littermates after Ang II stimulation. This functional deterioration was associated with altered expression of the T-box proteins Tbx5 and Tbx20 at baseline and after Ang II stimulation. In addition, atrophy-related protein IGFBP5 was upregulated in ␤-catenin-stabilized mice. These data suggest that ␤-catenin downregulation is required for adaptive cardiac hypertrophy. (Circ Res.