Specific Heat Anomaly and Adiabatic Hysteresis in Disordered Electron Systems in a Magnetic Field

We consider the thermodynamic behavior of a disordered interacting electron system in two dimensions. We show that the corrections to the thermodynamic potential in the weakly localized regime give rise to a non monotonic behavior of the specific heat both in temperature and magnetic field. From this effect we predict the appearance of adiabatic hysteresis in the magnetoconductance. Our results can be interpreted as precursor effect of formation of local moments in disordered electron systems. We also comment on the relevance of our analysis in three dimensional systems.Comment: 4 pages, RevTeX, 3 figures, accepted by EPJ

A PDK1-dependent regulation of PLCγ1 activation is essential for cancer cell migration and invasion

PhDPhospholipase Cγ1 (PLCγ1) is highly expressed in several tumours such as breast carcinomas and has been found overexpressed in metastases compared to primary tumour in breast cancer patients, indicating that PLCγ1 may be important in tumourigenesis and metastasis dissemination. PLCγ1 involvement in cancer cell motility and in cancer cell Matrigel invasion was investigated. Downregulation of PLCγ1 protein expression by siRNA or shRNA inhibited Matrigel cell invasion of highly invasive breast and melanoma cancer cell lines. Furthermore PLCγ1 protein downregulation inhibits intracellular calcium mobilisation upon EGF stimulation demonstrating the essential role of PLCγ1 in EGF-induced calcium release. In the effort to identify specific PLCγ1 inhibitors, Inositol (1,3,4,5,6) pentakisphosphate (InsP5) and 2-O-Bn-InsP5, a synthetic compound based on InsP5 structure, were tested on Matrigel cell invasion and PLCγ1 activity. I found that InsP5 and 2-O-Bn-InsP5 reduce cell migration and Matrigel invasion in breast and melanoma cancer cell lines, with a complete inhibition displayed by 2-O-Bn-InsP5 treated cells. Furthermore InsP5 and 2-O-Bn-InsP5 treatment reduces calcium release upon EGF stimulation, with a complete inhibition showed by 2-O-Bn-InsP5 treated cells, suggesting a potential inhibition on PLCγ1 activity. Analysis of PLCγ1 phosphorylation in tyrosine 783 residue revealed that 2-O-Bn-InsP5 inhibits EGF-induced PLCγ1 tyrosine phosphorylation. Kinase profile assay, performed in vitro to test the inhibitory effect of InsP5 and 2-O-Bn-InsP5 on different kinases, showed a specific inhibition by 2-O-Bn-InsP5 of the 3-phosphoinositide-dependent-protein kinase 1 (PDK1) with an IC50 of 26 nM. Knock down of PDK1 using siRNA and shRNA in MDA-MB-231 showed impairment in cell migration and Matrigel invasion and inhibition of EGF-induced calcium mobilisation. Co-immunoprecipitation and FRET analyses showed that PLCγ1 and PDK1 associate in a protein complex. My finding identified a novel pathway which involves PDK1 in PLCγ1 activation. Furthermore this work highlights PLCγ1 as a potential therapeutic target to prevent metastases spreading and identified 2-O-Bn- InsP5 as a leading compound for development of anti-metastatic drugs

Thermal adaptability of Kluyveromyces marxianus in recombinant protein production

Background: Kluyveromyces marxianus combines the ease of genetic manipulation and fermentation with the ability to efficiently secrete high molecular weight proteins, performing eukaryotic post-translational modifications. It is able to grow efficiently in a wide range of temperatures. The secretion performances were analyzed in the host K. marxianus L3 in the range between 5\ub0C and 40\ub0C by means of 3 different reporter proteins, since temperature appears a key parameter for production and secretion of recombinant proteins.Results: The recombinant strains were able to grow up to 40\ub0C and, along the tested temperature interval (5-40\ub0C), the specific growth rates (\u3bc) were generally lower as compared to those of the untransformed strain. Biomass yields were slightly affected by temperature, with the highest values reached at 15\ub0C and 30\ub0C. The secretion of the endogenous \u3b2-fructofuranosidase, used as an internal control, was efficient in the range of the tested temperature, as evaluated by assaying the enzyme activity in the culture supernatants. The endogenous \u3b2-fructofuranosidase production was temperature dependent, with the highest yield at 30\ub0C. The heterologous proteins HSA, GAA and Sod1p were all successfully produced and secreted between 5\ub0C and 40\ub0C, albeit each one presented a different optimal production temperature (15, 40, 5-30\ub0C for HSA, GAA and Sod1p, respectively).Conclusions: K. marxianus L3 has been identified as a promising and flexible cell factory. In a sole host, the optimization of growth temperatures for the efficient secretion of each individual protein can be carried out over a wide range of temperatures

A Phosphoinositide 3-Kinase/Phospholipase Cgamma1 Pathway Regulates Fibroblast Growth Factor-Induced Capillary Tube Formation

Background: The fibroblast growth factors (FGFs) are key regulators of embryonic development, tissue homeostasis and tumour angiogenesis. Binding of FGFs to their receptor(s) results in activation of several intracellular signalling cascades including phosphoinositide 3-kinase (PI3K) and phospholipase C (PLC)gamma 1. Here we investigated the basic FGF (FGF-2)-mediated activation of these enzymes in human umbilical vein endothelial cells (HUVECs) and defined their role in FGF-2-dependent cellular functions.Methodology/Principal Findings: We show that FGF-2 activates PLC gamma 1 in HUVECs measured by analysis of total inositol phosphates production upon metabolic labelling of cells and intracellular calcium increase. We further demonstrate that FGF-2 activates PI3K, assessed by analysing accumulation of its lipid product phosphatidylinositol-3,4,5-P-3 using TLC and confocal microscopy analysis. PI3K activity is required for FGF-2-induced PLC gamma 1 activation and the PI3K/PLC gamma 1 pathway is involved in FGF-2-dependent cell migration, determined using Transwell assay, and in FGF-2-induced capillary tube formation (tubulogenesis assays in vitro). Finally we show that PI3K-dependent PLC gamma 1 activation regulates FGF-2-mediated phosphorylation of Akt at its residue Ser473, determined by Western blotting analysis. This occurs through protein kinase C (PKC)alpha activation since dowregulation of PKC alpha expression using specific siRNA or blockade of its activity using chemical inhibition affects the FGF-2-dependent Ser473 Akt phosphorylation. Furthermore inhibition of PKC alpha blocks FGF-2-dependent cell migration.Conclusion/Significance: These data elucidate the role of PLC gamma 1 in FGF-2 signalling in HUVECs demonstrating its key role in FGF-2-dependent tubulogenesis. Furthermore these data unveil a novel role for PLC gamma 1 as a mediator of PI3K-dependent Akt activation and as a novel key regulator of different Akt-dependent processes

Amyloid detection and typing yield of skin biopsy in systemic amyloidosis and polyneuropathy.

OBJECTIVE Disease-modifying therapies are available for amyloidosis but are ineffective if end-organ damage is severe. As small fiber neuropathy is an early and common feature of amyloidosis, we assessed detection and typing yield of skin biopsy for amyloid in patients with confirmed systemic amyloidosis and neuropathic symptoms. METHODS In this case-control study, patients with transthyretin and light chain amyloidosis (ATTRv, ATTRwt, and AL) were consecutively recruited. They were sex and age-matched to three control groups (1) non-neuropathic controls (NNC), (2) monoclonal gammopathy of undetermined significance (MGUS), and (3) other neuropathic disease controls (ONC). Patients underwent a double 3 mm skin biopsy in proximal and distal leg. Amyloid index and burden, protein typing by immuno-electron microscopy, intraepidermal nerve fiber density, electroneuromyography, and clinical characteristics were analyzed. RESULTS We studied 15 subjects with confirmed systemic amyloidosis, 20 NNC, 18 MGUS, and 20 ONC. Amyloid was detected in 100% of patients with amyloidosis (87% in ankle and 73% in thigh). It was not detected in any of the control groups. A small fiber neuropathy was encountered in 100% of amyloidosis patients, in 80% of MGUS, and in 78% of ONC. Amyloid burden was higher in ATTRv, followed by AL and ATTRwt. The ultrastructural examination allowed the identification of the precursor protein by immunotyping in most of the cases. INTERPRETATION Skin biopsy is a minimally invasive test with optimal sensitivity for amyloid. It allows amyloid typing by electron microscope to identify the precursor protein. The diagnostic work up of systemic amyloidosis should include a skin biopsy

Performance autoethnography and qualitative research in Collective Health: methodological (mis)encounters

Performance autoethnography is qualitative research methodology that aims to problematize resistances between the “self” (auto-) and the collective (ethno-) in the act of writing (-graphy). The article thus aims to discuss the theoretical and practical construction of performance autoethnography and its applicability as a qualitative research and analytical method in the field of Collective Health through a performance autoethnography writing. By problematizing the epistemic and ontological basis of performance autoethnography, pointing to possibilities for its development and inclusion in studies in the field of Collective Health, the article presents performance autoethnography as a strategy to expand the possibilities for social justice, democratization, and pluralisms in and from research practices. Performance autoethnography, oriented by the episteme “postcolonial”, explores decolonializing approaches that provoke and create conditions for the transformation of the academic view itself and the knowledge that prioritizes certain representations of “the other” and thus mainly problematizes how subaltern and marginalized histories relate to what are considered hegemonic systems

Imatinib inhibits VEGF-independent angiogenesis by targeting neuropilin 1-dependent ABL1 activation in endothelial cells.

To enable new blood vessel growth, endothelial cells (ECs) express neuropilin 1 (NRP1), and NRP1 associates with the receptor tyrosine kinase VEGFR2 after binding the vascular endothelial growth factor A (VEGF) to enhance arteriogenesis. We report that NRP1 contributes to angiogenesis through a novel mechanism. In human and mouse ECs, the integrin ligand fibronectin (FN) stimulated actin remodeling and phosphorylation of the focal adhesion component paxillin (PXN) in a VEGF/VEGFR2-independent but NRP1-dependent manner. NRP1 formed a complex with ABL1 that was responsible for FN-dependent PXN activation and actin remodeling. This complex promoted EC motility in vitro and during angiogenesis on FN substrates in vivo. Accordingly, both physiological and pathological angiogenesis in the retina were inhibited by treatment with Imatinib, a small molecule inhibitor of ABL1 which is widely used to prevent the proliferation of tumor cells that express BCR-ABL fusion proteins. The finding that NRP1 regulates angiogenesis in a VEGF- and VEGFR2-independent fashion via ABL1 suggests that ABL1 inhibition provides a novel opportunity for anti-angiogenic therapy to complement VEGF or VEGFR2 blockade in eye disease or solid tumor growth