Modeling the TNFα-Induced Apoptosis Pathway in Hepatocytes

The proinflammatory cytokine TNFα fails to provoke cell death in isolated hepatocytes but has been implicated in hepatocyte apoptosis during liver diseases associated with chronic inflammation. Recently, we showed that TNFα is able to sensitize primary murine hepatocytes cultured on collagen to Fas ligand-induced apoptosis and presented a mathematical model of the sensitizing effect. Here, we analyze how TNFα induces apoptosis in combination with the transcriptional inhibitor actinomycin D (ActD). Accumulation of reactive oxygen species (ROS) in response to TNFR activation turns out to be critical for sustained activation of JNK which then triggers mitochondrial pathway-dependent apoptosis. In addition, the amount of JNK is strongly upregulated in a ROS-dependent way. In contrast to TNFα plus cycloheximide no cFLIP degradation is observed suggesting a different apoptosis pathway in which the Itch-mediated cFLIP degradation and predominantly caspase-8 activation is not involved. Time-resolved data of the respective pro- and antiapoptotic factors are obtained and subjected to mathematical modeling. On the basis of these data we developed a mathematical model which reproduces the complex interplay regulating the phosphorylation status of JNK and generation of ROS. This model was fully integrated with our model of TNFα/Fas ligand sensitizing as well as with a published NF-κB-model. The resulting comprehensive model delivers insight in the dynamical interplay between the TNFα and FasL pathways, NF-κB and ROS and gives an example for successful model integration

Identification of Hypoxia-Regulated Proteins Using MALDI-Mass Spectrometry Imaging Combined with Quantitative Proteomics

Hypoxia is present in most solid tumors and is clinically correlated with increased metastasis and poor patient survival. While studies have demonstrated the role of hypoxia and hypoxia-regulated proteins in cancer progression, no attempts have been made to identify hypoxia-regulated proteins using quantitative proteomics combined with MALDI-mass spectrometry imaging (MALDI-MSI). Here we present a comprehensive hypoxic proteome study and are the first to investigate changes in situ using tumor samples. In vitro quantitative mass spectrometry analysis of the hypoxic proteome was performed on breast cancer cells using stable isotope labeling with amino acids in cell culture (SILAC). MS analyses were performed on laser-capture microdissected samples isolated from normoxic and hypoxic regions from tumors derived from the same cells used in vitro. MALDI-MSI was used in combination to investigate hypoxia-regulated protein localization within tumor sections. Here we identified more than 100 proteins, both novel and previously reported, that were associated with hypoxia. Several proteins were localized in hypoxic regions, as identified by MALDI-MSI. Visualization and data extrapolation methods for the in vitro SILAC data were also developed, and computational mapping of MALDI-MSI data to IHC results was applied for data validation. The results and limitations of the methodologies described are discussed. 2014 American Chemical Societ

Political parties and power: a new framework for analysis

Political parties are both vehicles for the pursuit of power and specific sites in which it is produced, organised, fought over, captured and lost. However, the literature on parties has not kept up with theoretical developments and largely lacks an explicit, systematic theorisation of power. To address this, a framework of power is proposed in this article that introduces some of the more nuanced and sophisticated insights of political theory to the analysis of parties without dismissing the benefits of more established approaches. Power is approached as a rich, multilayered concept, derived from diverse intellectual traditions. The framework acts as a heuristic which encapsulates individual agency, the strategic mobilisation of rules and norms, rationalisation and bureaucracy, the constitution of agents and the micro-level discipline of bodies. This provides a more satisfying framework for analysing power in parties than has previously been offered

Gender representation in Wales: new approaches to candidate selection in UK's devolved legislatures and beyond

Gender represents a very important, yet often neglected, element of political and constitutional change. The UK is an example of a state in relative constitutional flux where gender and constitutional reform have been closely intertwined. Alongside, the constitutional change has developed a ‘new’ politics, derived from democratic renewal (especially devolution in Scotland, Wales and Northern Ireland post-1997). This has created conditions for a renewed debate on women representation in UK’s political and public life and has also stimulated some innovations (and in some cases, transformations) of internal candidate selection strategies within parties. This has resulted in a degree of better representation for women elected to the various UK legislatures. Nevertheless, twenty years on from devolution, progress for women is stagnating at subnational level (and desperately slow at UK Parliament and local government level). This chapter explores changes in the electoral opportunity structures for women in post-devolution UK, using Wales and its National Assembly as a case study. It will focus specifically on how internal candidate selection processes within the main political parties in Wales—Labour, Conservative and Plaid Cymru—have changed against a backdrop of constitutional reform, whilst also unpacking gender from the recent electoral success of UKIP. We explore the impact the changes in candidate selection processes have had on women’s electoral fortunes and the descriptive representation of women in UK legislatures. We draw on empirical work on UK’s constitutional transformation undertaken by the authors since the beginning of devolution. Our findings highlight the importance of endogenous and exogenous factors, both structural and cultural, in diversifying pathways into politics for women through innovative approaches to candidate selection strategies within parties, and through addressing structural barriers outside political parties. We argue that whilst the ‘new’ politics has brought some changes to electoral opportunity structures for women at subnational level, there has been no real cascading effect of positive changes at other levels, a culture of bias still stifling the internal party processes of selecting candidates