Nuclear Segmentation, Condensation and Bilateral Symmetry in Polymorphonuclear Leukocytes Reflect Genomic Order and Favor Immunologic Function

Segmentation, condensation and bilateral symmetry of the nuclei ofpolymorphonuclear leukocytes seem related to their function.Segmentation of the nuclei into two or more lobes and their condensationfacilitate their passage (diapedesis) through the endothelial layer ofblood vessels to the extravasal space and subsequent locomotion throughthe interstitial compartment of different tissues. Bilateral symmetry ofthese nuclei along with their association to the cytoskeletal fiberscontribute to their efficiency in locomotion by alignment of the axis ofnuclear symmetry to the axis of cellular polarity, which orients towardsthe direction of locomotion in response to cytokines and other stimuli.Observations of the cytogenetic facets of intranuclear order supportthese assumptions

Direct observation of molecular cooperativity near the glass transition

We describe direct observations of molecular cooperativity near the glass transition in poly-vinyl-acetate (PVAc), through nanometer-scale probing of dielectric fluctuations. Molecular clusters switched spontaneously between two to four distinct configurations, producing complex random-telegraph-signals (RTS). Analysis of the RTS and their power spectra shows that individual clusters exhibit both transient dynamical heterogeneity and non-exponential kinetics.Comment: 14 pages pdf, need Acrobat Reade

The Sec61p Complex Mediates the Integration of a Membrane Protein by Allowing Lipid Partitioning of the Transmembrane Domain

AbstractWe have investigated how the transmembrane (TM) domain of a membrane protein is cotranslationally integrated into the endoplasmic reticulum. We demonstrate that the Sec61p channel allows the TM domain to bypass the barrier posed by the polar head groups of the lipid bilayer and come into contact with the hydrophobic interior of the membrane. Together with the TRAM protein, Sec61p provides a site in the membrane, at the interface of channel and lipid, through which a TM domain can dynamically equilibrate between the lipid and aqueous phases, depending on the hydrophobicity of the TM domain and the length of the polypeptide segment tethering it to the ribosome. Our results suggest a unifying, lipid-partitioning model which can explain the general behavior of hydrophobic topogenic sequences

S100A4 in cancer metastasis: Wnt signaling-driven interventions for metastasis restriction

The aberrant activity of Wnt signaling is an early step in the transformation of normal intestinal cells to malignant tissue, leading to more aggressive tumors, and eventually metastases. In colorectal cancer (CRC), metastasis accounts for about 90% of patient deaths, representing the most lethal event during the course of the disease and is directly linked to patient survival, critically limiting successful therapy. This review focuses on our studies of the metastasis-inducing gene S100A4, which we identified as transcriptional target of {beta}-catenin. S100A4 increased migration and invasion in vitro and metastasis in mice. In patient CRC samples, high S100A4 levels predict metastasis and reduced patient survival. Our results link pathways important for tumor progression and metastasis: the Wnt signaling pathway and S100A4, which regulates motility and invasiveness. S100A4 suppression by interdicting Wnt signaling has potential for therapeutic intervention. As proof of principle, we applied S100A4 shRNA systemically and prevented metastasis in mice. Furthermore, we identified small molecule inhibitors from high-throughput screens of pharmacologically active compounds employing an S100A4 promoter-driven reporter. Best hits act, as least in part, via intervening in the Wnt pathway and restricted metastasis in mouse models. We currently translate our findings on restricting S100A4-driven metastasis into clinical practice. The repositioned FDA-approved drug niclosamide, targeting Wnt signaling, is being tested in a prospective phase II clinical trial for treatment of CRC patients. Our assay for circulating S100A4 transcripts in patient blood is used to monitor treatment success

Uptake, biodistribution, and time course of naked plasmid DNA trafficking after intratumoral in vivo jet injection

Nonviral jet injection is an applicable technology for in vivo gene transfer of naked DNA. However, little is known about the biodistribution and clearance of jet-injected DNA, or about its localization within tissue and cells. Therefore, in this study we analyzed the intratumoral and systemic biodistribution of jet-injected naked DNA in human colon carcinoma-bearing NCr-nu/nu mice, which were jet-injected with the pCMVbeta plasmid DNA. Intratumoral and systemic plasmid DNA biodistribution was analyzed 5, 10, 20, and 40 min and 3, 6, 24, 48, and 72 hr after jet injection, using quantitative real-time polymerase chain reaction. In the tumors, a rapid drop in naked DNA load within 24 hr of jet injection was shown. Detailed analysis of intratumoral distribution of rhodamine-labeled DNA revealed the presence of plasmid DNA within tumor cells 5 min after jet injection and further accumulation of significant DNA amounts in the cell nuclei 30 to 60 min after jet injection. In the blood, DNA amounts rapidly dropped within 10 to 40 min of jet injection to less than 0.001 pg of plasmid per 250 ng of tissue DNA and only minimal plasmid DNA dissemination was detected in liver, lung, spleen, kidney, and ovaries, which was cleared 3 to 6 hr after jet injection. By contrast, in heart, bone marrow, and brain almost no plasmid DNA was detectable