Influence of pre-strain and bake hardening on the static and fatigue strength of a DP600 steel sheet

The influence of pre-strain on the tensile and fatigue properties of a dual phase DP600 steel was studied. The material was pre-strained by uni-axial tension in rolling and transverse direction. Thereafter, specimens were cut from the deformed plates in parallel or orthogonal to pre-strain direction. It was found that pre-strain increases yield and tensile strength. Results suggested that strain path change primarily affects the elastic-plastic transition during early stage of reloading. Pre-strained specimens showed an increase in high cycle regimes as a consequence of yield strength increment, irrespective of imposed pre-straining direction. A modified stress life equation that accounts for pre-strain was proposed and showed good agreement with experimental data. Bake hardening enhanced both tensile and high cycle fatigue resistance. Walker equation was successfully fitted to account for tensile mean stress. In low cycle fatigue, negligible influence of pre-strain was observed due to cyclic softening and residual stress relaxation

AKAP2-anchored protein phosphatase 1 controls prostatic neuroendocrine carcinoma cell migration and invasion.

Prostate cancer (PC) is the second leading cause of cancer-related death in men. The growth of primary prostate cancer cells relies on circulating androgens and thus the standard therapy for the treatment of localized and advanced PC is the androgen deprivation therapy. Prostatic neuroendocrine carcinoma (PNEC) is an aggressive and highly metastatic subtype of prostate cancer, which displays poor prognosis and high lethality. Most of PNECs develop from prostate adenocarcinoma in response to androgen deprivation therapy, however the mechanisms involved in this transition and in the elevated biological aggressiveness of PNECs are poorly defined. Our current findings indicate that AKAP2 expression is dramatically upregulated in PNECs as compared to non-cancerous prostate tissues. Using a PNEC cell model, we could show that AKAP2 is localized both intracellularly and at the cell periphery where it colocalizes with F-actin. AKAP2 and F-actin interact directly through a newly identified actin-binding domain located on AKAP2. RNAi-mediated silencing of AKAP2 promotes the phosphorylation and deactivation of cofilin, a protein involved in actin turnover. This effect correlates with a significant reduction in cell migration and invasion. Co-immunoprecipitation experiments and proximity ligation assays revealed that AKAP2 forms a complex with the catalytic subunit of protein phosphatase 1 (PP1) in PNECs. Importantly, AKAP2-mediated anchoring of PP1 to the actin cytoskeleton regulates cofilin dephosphorylation and activation, which, in turn, enhances F-actin dynamics and favors migration and invasion. In conclusion, this study identified AKAP2 as an anchoring protein overexpressed in PNECs that controls cancer cell invasive properties by regulating cofilin phosphorylation

Comparative transcriptome profiling of the injured zebrafish and mouse hearts identifies miRNA-dependent repair pathways.

The adult mammalian heart has poor regenerative capacity. In contrast, the zebrafish heart retains a robust capacity for regeneration into adulthood. These distinct responses are consequences of a differential utilization of evolutionary-conserved gene regulatory networks in the damaged heart. To systematically identify miRNA-dependent networks controlling cardiac repair following injury, we performed comparative gene and miRNA profiling of the cardiac transcriptome in adult mice and zebrafish. Using an integrated approach, we show that 45 miRNA-dependent networks, involved in critical biological pathways, are differentially modulated in the injured zebrafish vs. mouse hearts. We study, more particularly, the miR-26a-dependent response. Therefore, miR-26a is down-regulated in the fish heart after injury, whereas its expression remains constant in the mouse heart. Targets of miR-26a involve activators of the cell cycle and Ezh2, a component of the polycomb repressive complex 2 (PRC2). Importantly, PRC2 exerts repressive functions on negative regulators of the cell cycle. In cultured neonatal cardiomyocytes, inhibition of miR-26a stimulates, therefore, cardiomyocyte proliferation. Accordingly, miR-26a knockdown prolongs the proliferative window of cardiomyocytes in the post-natal mouse heart. This novel strategy identifies a series of miRNAs and associated pathways, in particular miR-26a, which represent attractive therapeutic targets for inducing repair in the injured heart

AKAP-Lbc mobilizes a cardiac hypertrophy signaling pathway.

Elevated catecholamines in the heart evoke transcriptional activation of the Myocyte Enhancer Factor (MEF) pathway to induce a cellular response known as pathological myocardial hypertrophy. We have discovered that the A-Kinase Anchoring Protein (AKAP)-Lbc is upregulated in hypertrophic cardiomyocytes. It coordinates activation and movement of signaling proteins that initiate MEF2-mediated transcriptional reprogramming events. Live-cell imaging, fluorescent kinase activity reporters, and RNA interference techniques show that AKAP-Lbc couples activation of protein kinase D (PKD) with the phosphorylation-dependent nuclear export of the class II histone deacetylase HDAC5. These studies uncover a role for AKAP-Lbc in which increased expression of the anchoring protein selectively amplifies a signaling pathway that drives cardiac myocytes toward a pathophysiological outcome

Creative Industries in India Mapping Study

No abstract available

Differences in the signaling pathways of α1A- and α1B-adrenoceptors are related to different endosomal targeting

Aims: To compare the constitutive and agonist-dependent endosomal trafficking of α1A- and α1B-adrenoceptors (ARs) and to establish if the internalization pattern determines the signaling pathways of each subtype. Methods: Using CypHer5 technology and VSV-G epitope tagged α1A- and α1B-ARs stably and transiently expressed in HEK 293 cells, we analyzed by confocal microscopy the constitutive and agonist-induced internalization of each subtype, and the temporal relationship between agonist induced internalization and the increase in intracellular calcium (determined by FLUO-3 flouorescence), or the phosphorylation of ERK1/2 and p38 MAP kinases (determined by Western blot). Results and Conclusions: Constitutive as well as agonist-induced trafficking of α1A and α1B ARs maintain two different endosomal pools of receptors: one located close to the plasma membrane and the other deeper into the cytosol. Each subtype exhibited specific characteristics of internalization and distribution between these pools that determines their signaling pathways: α1A-ARs, when located in the plasma membrane, signal through calcium and ERK1/2 pathways but, when translocated to deeper endosomes, through a mechanism sensitive to β-arrestin and concanavalin A, continue signaling through ERK1/2 and also activate the p38 pathway. α1B-ARs signal through calcium and ERK1/2 only when located in the membrane and the signals disappear after endocytosis and by disruption of the membrane lipid rafts by methyl-β-cyclodextrin

Mutations in pericentrin cause Seckel syndrome with defective ATR-dependent DNA damage signaling

Large brain size is one of the defining characteristics of modern humans. Seckel syndrome (MIM 210600), a disorder of markedly reduced brain and body size, is associated with defective ATR-dependent DNA damage signaling. Only a single hypomorphic mutation of ATR has been identified in this genetically heterogeneous condition. We now report that mutations in the gene encoding pericentrin (PCNT)--resulting in the loss of pericentrin from the centrosome, where it has key functions anchoring both structural and regulatory proteins--also cause Seckel syndrome. Furthermore, we find that cells of individuals with Seckel syndrome due to mutations in PCNT (PCNT-Seckel) have defects in ATR-dependent checkpoint signaling, providing the first evidence linking a structural centrosomal protein with DNA damage signaling. These findings also suggest that other known microcephaly genes implicated in either DNA repair responses or centrosomal function may act in common developmental pathways determining human brain and body size

Small-Molecule Protein-Protein Interaction Inhibitor of Oncogenic Rho Signaling

Uncontrolled activation of Rho signaling by RhoGEFs, in particular AKAP13 (Lbc) and its close homologs, is implicated in a number of human tumors with poor prognosis and resistance to therapy. Structure predictions and alanine scanning mutagenesis of Lbc identified a circumscribed hot region for RhoA recognition and activation. Virtual screening targeting that region led to the discovery of an inhibitor of Lbc-RhoA interaction inside cells. By interacting with the DH domain, the compound inhibits the catalytic activity of Lbc, halts cellular responses to activation of oncogenic Lbc pathways, and reverses a number of prostate cancer cell phenotypes such as proliferation, migration, and invasiveness. This study provides insights into the structural determinants of Lbc-RhoA recognition. This is a successful example of structure-based discovery of a small protein-protein interaction inhibitor able to halt oncogenic Rho signaling in cancer cells with therapeutic implications

The α1-adrenergic receptors: diversity of signaling networks and regulation

The α1-adrenergic receptor (AR) subtypes (α1a, α1b, and α1d) mediate several physiological effects of epinephrineand norepinephrine. Despite several studies in recombinant systems and insightfrom genetically modified mice, our understanding of the physiological relevance and specificity of the α1-AR subtypes is still limited. Constitutive activity and receptor oligomerization have emerged as potential features regulating receptor function. Another recent paradigm is that βarrestins and G protein-coupled receptors themselves can act as scaffolds binding a variety of proteins and this can result in growing complexity of the receptor-mediated cellular effects. The aim of this review is to summarize our current knowledge on some recently identified functional paradigms and signaling networks that might help to elucidate the functional diversity of the α1-AR subtypes in various organs