Diacylglycerol kinase zeta inhibits G alpha q-induced atrial remodeling in transgenic mice

ArticleHEART RHYTHM. 6(1):78-84 (2009)journal articl

Differential regulation of diacylglycerol kinase isoform in human failing hearts

Evidence from several studies indicates the importance of Gαq protein-coupled receptor (GPCR) signaling pathway, which includes diacylglycerol (DAG), and protein kinase C, in the development of heart failure. DAG kinase (DGK) acts as an endogenous regulator of GPCR signaling pathway by catalyzing and regulating DAG. Expressions of DGK isoforms α, ε, and ζ in rodent hearts have been detected; however, the expression and alteration of DGK isoforms in a failing human heart has not yet been examined. In this study, we detected mRNA expressions of DGK isoforms γ, η, ε, and ζ in failing human heart samples obtained from patients undergoing cardiovascular surgery with cardiopulmonary bypass. Furthermore, we investigated modulation of DGK isoform expression in these hearts. We found that expressions of DGKη and DGKζ were increased and decreased, respectively, whereas those of DGKγ and DGKε remained unchanged. This is the first report that describes the differential regulation of DGK isoforms in normal and failing human hearts

Report on Tests and Measurements of Hadronic Interaction Properties with Air Showers

We present a summary of recent tests and measurements of hadronic interaction properties with air showers. This report has a special focus on muon density measurements. Several experiments reported deviations between simulated and recorded muon densities in extensive air showers, while others reported no discrepancies. We combine data from eight leading air shower experiments to cover shower energies from PeV to tens of EeV. Data are combined using the z-scale, a unified reference scale based on simulated air showers. Energy-scales of experiments are cross-calibrated. Above 10 PeV, we find a muon deficit in simulated air showers for each of the six considered hadronic interaction models. The deficit is increasing with shower energy. For the models EPOS-LHC and QGSJet-II.04, the slope is found significant at 8 sigma.Comment: Submitted to the Proceedings of UHECR201

Phosphorylation-dependent assembly and coordination of the DNA damage checkpoint apparatus by Rad4TopBP1

The BRCT-domain protein Rad4(TopBP1) facilitates activation of the DNA damage checkpoint in Schizosaccharomyces pombe by physically coupling the Rad9-Rad1-Hus1 clamp, the Rad3(ATR) -Rad26(ATRIP) kinase complex, and the Crb2(53BP1) mediator. We have now determined crystal structures of the BRCT repeats of Rad4(TopBP1), revealing a distinctive domain architecture, and characterized their phosphorylation-dependent interactions with Rad9 and Crb2(53BP1). We identify a cluster of phosphorylation sites in the N-terminal region of Crb2(53BP1) that mediate interaction with Rad4(TopBP1) and reveal a hierarchical phosphorylation mechanism in which phosphorylation of Crb2(53BP1) residues Thr215 and Thr235 promotes phosphorylation of the noncanonical Thr187 site by scaffolding cyclin-dependent kinase (CDK) recruitment. Finally, we show that the simultaneous interaction of a single Rad4(TopBP1) molecule with both Thr187 phosphorylation sites in a Crb2(53BP1) dimer is essential for establishing the DNA damage checkpoint

Mendelian randomization study of B-type natriuretic peptide and type 2 diabetes: evidence of causal association from population studies

<p>Background: Genetic and epidemiological evidence suggests an inverse association between B-type natriuretic peptide (BNP) levels in blood and risk of type 2 diabetes (T2D), but the prospective association of BNP with T2D is uncertain, and it is unclear whether the association is confounded.</p> <p>Methods and Findings: We analysed the association between levels of the N-terminal fragment of pro-BNP (NT-pro-BNP) in blood and risk of incident T2D in a prospective case-cohort study and genotyped the variant rs198389 within the BNP locus in three T2D case-control studies. We combined our results with existing data in a meta-analysis of 11 case-control studies. Using a Mendelian randomization approach, we compared the observed association between rs198389 and T2D to that expected from the NT-pro-BNP level to T2D association and the NT-pro-BNP difference per C allele of rs198389. In participants of our case-cohort study who were free of T2D and cardiovascular disease at baseline, we observed a 21% (95% CI 3%-36%) decreased risk of incident T2D per one standard deviation (SD) higher log-transformed NT-pro-BNP levels in analysis adjusted for age, sex, body mass index, systolic blood pressure, smoking, family history of T2D, history of hypertension, and levels of triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. The association between rs198389 and T2D observed in case-control studies (odds ratio = 0.94 per C allele, 95% CI 0.91-0.97) was similar to that expected (0.96, 0.93-0.98) based on the pooled estimate for the log-NT-pro-BNP level to T2D association derived from a meta-analysis of our study and published data (hazard ratio = 0.82 per SD, 0.74-0.90) and the difference in NT-pro-BNP levels (0.22 SD, 0.15-0.29) per C allele of rs198389. No significant associations were observed between the rs198389 genotype and potential confounders.</p> <p>Conclusions: Our results provide evidence for a potential causal role of the BNP system in the aetiology of T2D. Further studies are needed to investigate the mechanisms underlying this association and possibilities for preventive interventions.</p&gt

The diacylglycerol kinase α/Atypical PKC/β1 integrin pathway in SDF-1α mammary carcinoma invasiveness

Diacylglycerol kinase α (DGKα), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKα activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of α5β1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKα mediates SDF-1α-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1α stimulation, DGKα is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1α induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKα promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKα by promoting Rac-mediated protrusion elongation and localized recruitment of β1 integrin and MMP-9. We finally demonstrate that activation of DGKα, atypical PKCs signaling and β1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1α induced DGKα - atypical PKC - β1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells

Assembly and Function of a Bioengineered Human Liver for Transplantation Generated Solely from Induced Pluripotent Stem Cells

The availability of an autologous transplantable auxiliary liver would dramatically affect the treatment of liver disease. Assembly and function in vivo of a bioengineered human liver derived from induced pluripotent stem cells (iPSCs) has not been previously described. By improving methods for liver decellularization, recellularization, and differentiation of different liver cellular lineages of human iPSCs in an organ-like environment, we generated functional engineered human mini livers and performed transplantation in a rat model. Whereas previous studies recellularized liver scaffolds largely with rodent hepatocytes, we repopulated not only the parenchyma with human iPSC-hepatocytes but also the vascular system with human iPS-endothelial cells, and the bile duct network with human iPSC-biliary epithelial cells. The regenerated human iPSC-derived mini liver containing multiple cell types was tested in vivo and remained functional for 4 days after auxiliary liver transplantation in immunocompromised, engineered (IL2rg−/−) rats.Fil: Takeishi, Kazuki. University of Pittsburgh; Estados UnidosFil: Collin de I'Hortet, Alexandra. University of Pittsburgh; Estados UnidosFil: Wang, Yang. University of Pittsburgh; Estados UnidosFil: Handa, Kan. University of Pittsburgh; Estados UnidosFil: Guzman Lepe, Jorge. University of Pittsburgh; Estados UnidosFil: Matsubara, Kentaro. University of Pittsburgh; Estados UnidosFil: Morita, Kazutoyo. University of Pittsburgh; Estados UnidosFil: Jang, Sae. University of Pittsburgh; Estados UnidosFil: Haep, Nils. University of Pittsburgh; Estados UnidosFil: Florentino, Rodrigo M.. University of Pittsburgh; Estados UnidosFil: Yuan, Fangchao. University of Pittsburgh; Estados UnidosFil: Fukumitsu, Ken. University of Pittsburgh; Estados UnidosFil: Tobita, Kimimasa. University of Pittsburgh; Estados UnidosFil: Sun, Wendell. University of Pittsburgh; Estados UnidosFil: Franks, Jonathan. University of Pittsburgh; Estados UnidosFil: Delgado, Evan R.. University of Pittsburgh; Estados UnidosFil: Shapiro, Erik M.. University of Pittsburgh; Estados UnidosFil: Fraunhoffer Navarro, Nicolas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Duncan, Andrew W.. University of Pittsburgh; Estados UnidosFil: Yagi, Hiroshi. University of Pittsburgh; Estados UnidosFil: Mashimo, Tomoji. University of Pittsburgh; Estados UnidosFil: Fox, Ira J.. University of Pittsburgh; Estados UnidosFil: Soto Gutierrez, Alejandro. University of Pittsburgh; Estados Unido

Protein kinase Cθ is required for cardiomyocyte survival and cardiac remodeling

Protein kinase Cs (PKCs) constitute a family of serine/threonine kinases, which has distinguished and specific roles in regulating cardiac responses, including those associated with heart failure. We found that the PKCθ isoform is expressed at considerable levels in the cardiac muscle in mouse, and that it is rapidly activated after pressure overload. To investigate the role of PKCθ in cardiac remodeling, we used PKCθ−/− mice. In vivo analyses of PKCθ−/− hearts showed that the lack of PKCθ expression leads to left ventricular dilation and reduced function. Histological analyses showed a reduction in the number of cardiomyocytes, combined with hypertrophy of the remaining cardiomyocytes, cardiac fibrosis, myofibroblast hyper-proliferation and matrix deposition. We also observed p38 and JunK activation, known to promote cell death in response to stress, combined with upregulation of the fetal pattern of gene expression, considered to be a feature of the hemodynamically or metabolically stressed heart. In keeping with these observations, cultured PKCθ−/− cardiomyocytes were less viable than wild-type cardiomyocytes, and, unlike wild-type cardiomyocytes, underwent programmed cell death upon stimulation with α1-adrenergic agonists and hypoxia. Taken together, these results show that PKCθ maintains the correct structure and function of the heart by preventing cardiomyocyte cell death in response to work demand and to neuro-hormonal signals, to which heart cells are continuously exposed

Cellular Location of HNF4α is Linked With Terminal Liver Failure in Humans

Hepatocyte nuclear factor 4 alpha (HNF4α) is a transcription factor that plays a critical role in hepatocyte function, and HNF4α-based reprogramming corrects terminal liver failure in rats with chronic liver disease. In the livers of patients with advanced cirrhosis, HNF4α RNA expression levels decrease as hepatic function deteriorates, and protein expression is found in the cytoplasm. These findings could explain impaired hepatic function in patients with degenerative liver disease. In this study, we analyzed HNF4α localization and the pathways involved in post-translational modification of HNF4α in human hepatocytes from patients with decompensated liver function. RNA-sequencing analysis revealed that AKT-related pathways, specifically phospho-AKT, is down-regulated in cirrhotic hepatocytes from patients with terminal failure, in whom nuclear levels of HNF4α were significantly reduced, and cytoplasmic expression of HNF4α was increased. cMET was also significantly reduced in failing hepatocytes. Moreover, metabolic profiling showed a glycolytic phenotype in failing human hepatocytes. The contribution of cMET and phospho-AKT to nuclear localization of HNF4α was confirmed using Spearman's rank correlation test and pathway analysis, and further correlated with hepatic dysfunction by principal component analysis. HNF4α acetylation, a posttranslational modification important for nuclear retention, was also significantly reduced in failing human hepatocytes when compared with normal controls. Conclusion: These results suggest that the alterations in the cMET-AKT pathway directly correlate with HNF4α localization and level of hepatocyte dysfunction. This study suggests that manipulation of HNF4α and pathways involved in HNF4α posttranslational modification may restore hepatocyte function in patients with terminal liver failure.Fil: Florentino, Rodrigo M.. Univeristy of Pittsburgh. School of Medicine; Estados Unidos. Universidade Federal de Minas Gerais; BrasilFil: Fraunhoffer Navarro, Nicolas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Morita, Kazutoyo. University of Pittsburgh at Johnstown; Estados UnidosFil: Takeishi, Kazuki. University of Pittsburgh at Johnstown; Estados UnidosFil: Ostrowska, Alina. University of Pittsburgh at Johnstown; Estados UnidosFil: Achreja, Abhinav. Michigan State University; Estados UnidosFil: Animasahun, Olamide. Michigan State University; Estados UnidosFil: Haep, Nils. University of Pittsburgh at Johnstown; Estados UnidosFil: Arazov, Shohrat. University of Pittsburgh at Johnstown; Estados UnidosFil: Agarwal, Nandini. University of Pittsburgh at Johnstown; Estados UnidosFil: Collin de lHortet, Alexandra. University of Pittsburgh at Johnstown; Estados UnidosFil: Guzman Lepe, Jorge. University of Pittsburgh at Johnstown; Estados UnidosFil: Tafaleng, Edgar N.. University of Pittsburgh at Johnstown; Estados UnidosFil: Mukherjee, Amitava. University of Pittsburgh at Johnstown; Estados UnidosFil: Troy, Kris. University of Pittsburgh at Johnstown; Estados UnidosFil: Banerjee, Swati. University of Pittsburgh at Johnstown; Estados UnidosFil: Paranjpe, Shirish. University of Pittsburgh at Johnstown; Estados UnidosFil: Michalopoulos, George K.. University of Pittsburgh at Johnstown; Estados UnidosFil: Bell, Aaron. University of Pittsburgh at Johnstown; Estados UnidosFil: Nagrath, Deepak. Michigan State University; Estados UnidosFil: Hainer, Sarah J.. University of Pittsburgh at Johnstown; Estados UnidosFil: Fox, Ira J.. University of Pittsburgh at Johnstown; Estados UnidosFil: Soto Gutierrez, Alejandro. University of Pittsburgh at Johnstown; Estados Unido