Nucleobindin-1 regulates ECM degradation by promoting intra-Golgi trafficking of MMPs.

Matrix metalloproteinases (MMPs) degrade several ECM components and are crucial modulators of cell invasion and tissue organization. Although much has been reported about their function in remodeling ECM in health and disease, their trafficking across the Golgi apparatus remains poorly understood. Here we report that the cis-Golgi protein nucleobindin-1 (NUCB1) is critical for MMP2 and MT1-MMP trafficking along the Golgi apparatus. This process is Ca2+-dependent and is required for invasive MDA-MB-231 cell migration as well as for gelatin degradation in primary human macrophages. Our findings emphasize the importance of NUCB1 as an essential component of MMP transport and its overall impact on ECM remodeling. © 2020 Pacheco-Fernandez et al

Host cell species-specific effect of cyclosporine A on simian immunodeficiency virus replication

<p>Abstract</p> <p>Background</p> <p>An understanding of host cell factors that affect viral replication contributes to elucidation of the mechanism for determination of viral tropism. Cyclophilin A (CypA), a peptidyl-prolyl <it>cis-trans </it>isomerase (PPIase), is a host factor essential for efficient replication of human immunodeficiency virus type 1 (HIV-1) in human cells. However, the role of cyclophilins in simian immunodeficiency virus (SIV) replication has not been determined. In the present study, we examined the effect of cyclosporine A (CsA), a PPIase inhibitor, on SIV replication.</p> <p>Results</p> <p>SIV replication in human CEM-SS T cells was not inhibited but rather enhanced by treatment with CsA, which inhibited HIV-1 replication. CsA treatment of target human cells enhanced an early step of SIV replication. CypA overexpression enhanced the early phase of HIV-1 but not SIV replication, while CypA knock-down resulted in suppression of HIV-1 but not SIV replication in CEM-SS cells, partially explaining different sensitivities of HIV-1 and SIV replication to CsA treatment. In contrast, CsA treatment inhibited SIV replication in macaque T cells; CsA treatment of either virus producer or target cells resulted in suppression of SIV replication. SIV infection was enhanced by CypA overexpression in macaque target cells.</p> <p>Conclusions</p> <p>CsA treatment enhanced SIV replication in human T cells but abrogated SIV replication in macaque T cells, implying a host cell species-specific effect of CsA on SIV replication. Further analyses indicated a positive effect of CypA on SIV infection into macaque but not into human T cells. These results suggest possible contribution of CypA to the determination of SIV tropism.</p

Identification of microbial DNA in human cancer

<p>Abstract</p> <p>Background</p> <p>Microorganisms have been associated with many types of human diseases; however, a significant number of clinically important microbial pathogens remain to be discovered.</p> <p>Methods</p> <p>We have developed a genome-wide approach, called Digital Karyotyping Microbe Identification (DK-MICROBE), to identify genomic DNA of bacteria and viruses in human disease tissues. This method involves the generation of an experimental DNA tag library through Digital Karyotyping (DK) followed by analysis of the tag sequences for the presence of microbial DNA content using a compiled microbial DNA virtual tag library.</p> <p>Results</p> <p>To validate this technology and to identify pathogens that may be associated with human cancer pathogenesis, we used DK-MICROBE to determine the presence of microbial DNA in 58 human tumor samples, including brain, ovarian, and colorectal cancers. We detected DNA from Human herpesvirus 6 (HHV-6) in a DK library of a colorectal cancer liver metastasis and in normal tissue from the same patient.</p> <p>Conclusion</p> <p>DK-MICROBE can identify previously unknown infectious agents in human tumors, and is now available for further applications for the identification of pathogen DNA in human cancer and other diseases.</p

Susceptibility of Human Lymphoid Tissue Cultured ex vivo to Xenotropic Murine Leukemia Virus-Related Virus (XMRV) Infection

BACKGROUND: Xenotropic murine leukemia virus-related virus (XMRV) was generated after a recombination event between two endogenous murine leukemia viruses during the production of a prostate cancer cell line. Although the associations of the XMRV infection with human diseases appear unlikely, the XMRV is a retrovirus of undefined pathogenic potential, able to replicate in human cells in vitro. Since recent studies using animal models for infection have yielded conflicting results, we set out an ex vivo model for XMRV infection of human tonsillar tissue to determine whether XMRV produced by 22Rv1 cells is able to replicate in human lymphoid organs. Tonsil blocks were infected and infection kinetics and its pathogenic effects were monitored RESULTS: XMRV, though restricted by APOBEC, enters and integrates into the tissue cells. The infection did not result in changes of T or B-cells, immune activation, nor inflammatory chemokines. Infectious viruses could be recovered from supernatants of infected tonsils by reinfecting DERSE XMRV indicator cell line, although these supernatants could not establish a new infection in fresh tonsil culture, indicating that in our model, the viral replication is controlled by innate antiviral restriction factors. CONCLUSIONS: Overall, the replication-competent retrovirus XMRV, present in a high number of laboratories, is able to infect human lymphoid tissue and produce infectious viruses, even though they were unable to establish a new infection in fresh tonsillar tissue. Hereby, laboratories working with cell lines producing XMRV should have knowledge and understanding of the potential biological biohazardous risks of this virus

Two-dimensional cantilever array with varying spring constants and tip radii for life-science applications

A fabrication process for realising two-dimensional cantilever arrays for parallel force spectroscopy of biological samples is presented. The parallel optical atomic force microscopy readout system has been developed and presented elsewhere. The arrays are designed either for (i) force-indentation onto living cells to obtain stiffness mapping or (ii) cell adhesion experiments. Both experiments require very different spring constants and tip radii of curvature. The arrays are based on silicon nitride cantilevers with molded tips. The fabrication process includes an advanced molding process and a thermocompression bonding of two silicon wafers. V-groove structures along the cantilevers, which increase the area moment of inertia, were introduced in the cantilever design. This feature enables the fabrication of cantilevers with different spring constants but same footprint from one wafer. An analytical model and experimental results confirmed that the spring constant of the cantilever (200 x 50 x 0.45 mu m) could be increased up to two decades (0.03-5 N/m) by changing the depth of the V-grooves. To realise the large tip radius required for cell adhesion experiments, an enlarging/rounding procedure has been applied to a truncated pyramidal tip mold. With this process, the authors obtained tips with a radius up to 4 mu m

Measurement of quartz particles by means of an atomic force microscope for planetary exploration

Within the last 2 years our consortium has developed, built and tested an atomic force microscope for planetary science applications, in particular for the study of Martian dust and soil. An array of eight cantilevers and tips provides redundancy in case of tip or cantilever failure. Images can be recorded in both static and dynamic operation modes. As we plan to investigate Martian dust, our interest focuses on the behaviour of the instrument when measuring loose particles in the above-mentioned modes. During scanning, tip contamination with a particle occurs quite frequently, altering the quality of the images. Before changing the cantilever, reverse-imaging the contaminated tip on a tip calibration sample will be performed in order to increase the scientific throughput. We present the results of our test measurements on respirable α-quartz