Profiling biomolecules at cell-biomaterial interface by quantitative proteomics

Session: Controlling Microenvironment and Cell Fate: abstract no. 789INTRODUCTION: Implant surface structure and chemistry determines the contacting cell’s fate. Therefore, the fate of those cells directly affect bone-implant incorporation in clinical practice1-5. However, how these chemical and mechanical signals translating to cellular responses are not yet known. The major drawback is a lack of systematic study of cellbiomaterial interaction in terms of protein expression, specifically, at the attachment interface between the cell and biomaterial (adherence surface, AS). Therefore, we have proposed to unbiasedly identify the biomolecules at the interface by proteomics. This method combines the use of a subcellular fractionation with quantitative mass …postprintThe 2010 North America Conference of the Tissue Engineering and Regenerative Medicine International Society (TERMIS-NA 2010), Orlando, FL., 5-8 December 2010

Mitochondrial Function Is Required for Secretion of DAF-28/Insulin in C. elegans

While insulin signaling has been extensively studied in Caenorhabditis elegans in the context of ageing and stress response, less is known about the factors underlying the secretion of insulin ligands upstream of the insulin receptor. Activation of the receptor governs the decision whether to progress through the reproductive lifecycle or to arrest growth and enter hibernation. We find that animals with reduced levels of the mitochondrial outer membrane translocase homologue TOMM-40 arrest growth as larvae and have decreased insulin signaling strength. TOMM-40 acts as a mitochondrial translocase in C. elegans and in its absence animals fail to import a mitochondrial protein reporter across the mitochondrial membrane(s). Inactivation of TOMM-40 evokes the mitochondrial unfolded protein response and causes a collapse of the proton gradient across the inner mitochondrial membrane. Consequently these broadly dysfunctional mitochondria render an inability to couple food abundance to secretion of DAF-28/insulin. The secretion defect is not general in nature since two other neuropeptides, ANF::GFP and INS-22::VENUS, are secreted normally. RNAi against two other putative members of the TOMM complex give similar phenotypes, implying that DAF-28 secretion is sensitive to mitochondrial dysfunction in general. We conclude that mitochondrial function is required for C. elegans to secrete DAF-28/insulin when food is abundant. This modulation of secretion likely represents an additional level of control over DAF-28/insulin function

Fusion dual-tracer SPECT-based hepatic dosimetry predicts outcome after radioembolization for a wide range of tumour cell types

Purpose Fusion dual-tracer SPECT imaging enables physiological rather than morphological voxel-based partitioning and dosimetry for Y-90 hepatic radioembolization (RE). We evaluated its prognostic value in a large heterogeneous cohort of patients with extensive hepatic malignancy. Methods A total of 122 patients with primary or secondary liver malignancy (18 different cell types) underwent SPECT imaging after intraarterial injection of Tc-99m macroaggregated albumin (TcMAA) as a simulation of subsequent Y-90 microsphere distribution, followed by administration of an excess of intravenous Tc-99m-labelled sulphur colloid (TcSC) as a biomarker for functional liver, and a second SPECT scan. TcMAA distribution was used to estimate Y-90 radiation absorbed dose in tumour (D (T)) and in functional liver. Laboratory and clinical follow-up were recorded for 12 weeks after RE, and radiographic responses according to (m)RECIST were evaluated at 3 and 6 months. Dose-response relationships were determined for efficacy and toxicity. Results Patients were treated with a median of 1.73 GBq activity of resin microspheres (98 patients) or glass microspheres (24 patients), in a whole-liver approach (97 patients) or a lobar approach (25 patients). The objective response rate was 41 % at 3 months and 48 % at 6 months. Response was correlated with D (T) (P <0.01). Median overall survival was 10.1 months (95 % confidence interval 7.4 - 12.8 months). Responders lived for 36.0 months compared to 8.7 months for nonresponders (P <0.01). Stratified for tumour cell type, D (T) was independently associated with survival (P <0.01). Absorbed dose in functional liver was correlated with toxicity grade change (P <0.05) and RE-induced liver disease (P <0.05). Conclusion Fusion dual-tracer SPECT imaging offers a physiology-based functional imaging tool to predict efficacy and toxicity of RE. This technique can be refined to define dosing thresholds for specific tumour types and treatments, but appears generally predictive even in a heterogeneous cohort

A Directed RNAi Screen Based on Larval Growth Arrest Reveals New Modifiers of C. elegans Insulin Signaling

Genes regulating Caenorhabditis elegans insulin/IGF signaling (IIS) have largely been identified on the basis of their involvement in dauer development or longevity. A third IIS phenotype is the first larval stage (L1) diapause, which is also influenced by asna-1, a regulator of DAF-28/insulin secretion. We reasoned that new regulators of IIS strength might be identified in screens based on the L1 diapause and the asna-1 phenotype. Eighty- six genes were selected for analysis by virtue of their predicted interaction with ASNA-1 and screened for asna-1-like larval arrest. ykt-6, mrps-2, mrps-10 and mrpl-43 were identified as genes which, when inactivated, caused larval arrest without any associated feeding defects. Several tests indicated that IIS strength was weaker and that insulin secretion was defective in these animals. This study highlights the role of the Golgi network and the mitochondria in insulin secretion and provides a new list of genes that modulate IIS in C. elegans

Comparison of children's self-reports of depressive symptoms among different family interaction types in northern Taiwan

<p>Abstract</p> <p>Background</p> <p>Previous research has shown that family interactions are associated with depressive symptoms in children. However, detailed classifications of family interaction types have not been studied thoroughly. This study aims to understand the types of family interactions children experience and to identify the specific types of family interactions that are associated with a higher risk of depressive symptoms in children.</p> <p>Methods</p> <p>Data used in the study was collected as part of the Child and Adolescent Behavior in Long term Evolution (CABLE) project in 2003. CABLE is a longitudinal cohort study that commenced in 2001 and collects data annually from children in Taipei city and Hsinchu county in northern Taiwan. The data analyzed in this study was that obtained from the sixth graders (aged 11 to 12 years old) in 2003. Of the 2,449 sixth graders, 51.2% were boys and 48.8% were girls. Factor analysis and cluster analysis were used to investigate the types of family interactions. One way ANOVA was used to establish the relationship between family interaction types and children's self-reports of depressive symptoms.</p> <p>Results</p> <p>Based on the results of factor analysis, the latent factors for family interactions included supporting activities, psychological control, parental discipline, behavioral supervision, and family conflict. After conducting cluster analysis using factor scores, four types of family interactions were revealed: supervised (29.66%), disciplined (13.56%), nurtured (40.96%) and conflict (15.82%). Children from the disciplined or conflict families were more likely to report depressive symptoms. Children from the nurtured families were least likely to report depressive symptoms.</p> <p>Conclusion</p> <p>Family interactions can be classified into four different types, which are related to children's self-reports of depressive symptoms. The creation of a family interaction environment that is beneficial for children's mental health is an important issue for health education and health promotion professionals.</p

The G1613A Mutation in the HBV Genome Affects HBeAg Expression and Viral Replication through Altered Core Promoter Activity

Infection of hepatitis B virus (HBV) causes acute and chronic hepatitis and is closely associated with the development of cirrhosis and hepatocellular carcinoma (HCC). Previously, we demonstrated that the G1613A mutation in the HBV negative regulatory element (NRE) is a hotspot mutation in HCC patients. In this study, we further investigated the functional consequences of this mutation in the context of the full length HBV genome and its replication. We showed that the G1613A mutation significantly suppresses the secretion of e antigen (HBeAg) and enhances the synthesis of viral DNA, which is in consistence to our clinical result that the G1613A mutation associates with high viral load in chronic HBV carriers. To further investigate the molecular mechanism of the mutation, we performed the electrophoretic mobility shift assay with the recombinant RFX1 protein, a trans-activator that was shown to interact with the NRE of HBV. Intriguingly, RFX1 binds to the G1613A mutant with higher affinity than the wild-type sequence, indicating that the mutation possesses the trans-activating effect to the core promoter via NRE. The trans-activating effect was further validated by the enhancement of the core promoter activity after overexpression of RFX1 in liver cell line. In summary, our results suggest the functional consequences of the hotspot G1613A mutation found in HBV. We also provide a possible molecular mechanism of this hotspot mutation to the increased viral load of HBV carriers, which increases the risk to HCC