Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro

Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material

Interaction of silver nanoparticles with Tacaribe virus

<p>Abstract</p> <p>Background</p> <p>Silver nanoparticles possess many unique properties that make them attractive for use in biological applications. Recently they received attention when it was shown that 10 nm silver nanoparticles were bactericidal, which is promising in light of the growing number of antibiotic resistant bacteria. An area that has been largely unexplored is the interaction of nanomaterials with viruses and the possible use of silver nanoparticles as an antiviral agent.</p> <p>Results</p> <p>This research focuses on evaluating the interaction of silver nanoparticles with a New World arenavirus, Tacaribe virus, to determine if they influence viral replication. Surprisingly exposing the virus to silver nanoparticles prior to infection actually facilitated virus uptake into the host cells, but the silver-treated virus had a significant reduction in viral RNA production and progeny virus release, which indicates that silver nanoparticles are capable of inhibiting arenavirus infection <it>in vitro</it>. The inhibition of viral replication must occur during early replication since although pre-infection treatment with silver nanoparticles is very effective, the post-infection addition of silver nanoparticles is only effective if administered within the first 2-4 hours of virus replication.</p> <p>Conclusions</p> <p>Silver nanoparticles are capable of inhibiting a prototype arenavirus at non-toxic concentrations and effectively inhibit arenavirus replication when administered prior to viral infection or early after initial virus exposure. This suggests that the mode of action of viral neutralization by silver nanoparticles occurs during the early phases of viral replication.</p

Aluminum induces inflammatory and proteolytic alterations in human monocytic cell line

none4noThe increasing exposure to aluminum has been linked with the development of different human pathologies (e.g., breast cancer, myofasciitis, neurodegenerative diseases), probably due to the consistent presence of aluminum salts in widely diffused cosmetic products and vaccines. However, the mechanisms underlying immunologic and proliferative alterations still remain unknown. In the present study we investigated the ability of different aluminum compounds (i.e., aluminum chloride vs Imject® Alum, a mixture of aluminum and magnesium hydroxide) to trigger both inflammatory and proteolytic responses in U-937 human monocytic cell line. We demonstrated, by multiplex immunoassay analyses, that monocytic cells treated with both Imject Alum and aluminum chloride showed different and peculiar expression profiles of 27 inflammatory mediators and 5 matrix metalloproteinases, with respect to untreated control cells. In particular, we found dose-dependent significantly increased levels of pro-inflammatory cytokines, growth factors, and chemoattractant chemokines; whereas among metalloproteinases, only collagenolytic protease showed a significant dose-dependent increase in Imject-treated cells with respect to controls and Al-chloride treated cells. Noteworthy, we found only in Imject Alum-treated cells the significant positive correlations among collagenolytic metalloproteinase and increased expression of pro-inflammatory chemokines, suggesting a possible involvement of aluminum in regulating the acute inflammatory responses. In agreement to emerging evidences, for the first time we demonstrated that the treatment of monocyte cells with aluminum-based adjuvant is able to induce an inflammatory status and a proteolytic cascade activation. In fact, the cell treatment with Imject Alum induced increased levels of several cytokines and proteinases, suggesting these monocyte mediators as possible biomarkers for aluminum-linked diseases. The identification of the biochemical pathways involved in Al-induced cell injury pave the way for improving the knowledge on the potential impact of aluminum in human physio-pathology.openLigi, D; Santi, M; Croce, L; Mannello, FLigi, Daniela; Santi, Martina; Croce, L; Mannello, Ferdinand

Biomimetic, Mild Chemical Synthesis of CdTe-GSH Quantum Dots with Improved Biocompatibility

Multiple applications of nanotechnology, especially those involving highly fluorescent nanoparticles (NPs) or quantum dots (QDs) have stimulated the research to develop simple, rapid and environmentally friendly protocols for synthesizing NPs exhibiting novel properties and increased biocompatibility

Cyclical and Patch-Like GDNF Distribution along the Basal Surface of Sertoli Cells in Mouse and Hamster Testes

BACKGROUND AND AIMS: In mammalian spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) is one of the major Sertoli cell-derived factors which regulates the maintenance of undifferentiated spermatogonia including spermatogonial stem cells (SSCs) through GDNF family receptor α1 (GFRα1). It remains unclear as to when, where and how GDNF molecules are produced and exposed to the GFRα1-positive spermatogonia in vivo. METHODOLOGY AND PRINCIPAL FINDINGS: Here we show the cyclical and patch-like distribution of immunoreactive GDNF-positive signals and their close co-localization with a subpopulation of GFRα1-positive spermatogonia along the basal surface of Sertoli cells in mice and hamsters. Anti-GDNF section immunostaining revealed that GDNF-positive signals are mainly cytoplasmic and observed specifically in the Sertoli cells in a species-specific as well as a seminiferous cycle- and spermatogenic activity-dependent manner. In contrast to the ubiquitous GDNF signals in mouse testes, high levels of its signals were cyclically observed in hamster testes prior to spermiation. Whole-mount anti-GDNF staining of the seminiferous tubules successfully visualized the cyclical and patch-like extracellular distribution of GDNF-positive granular deposits along the basal surface of Sertoli cells in both species. Double-staining of GDNF and GFRα1 demonstrated the close co-localization of GDNF deposits and a subpopulation of GFRα1-positive spermatogonia. In both species, GFRα1-positive cells showed a slender bipolar shape as well as a tendency for increased cell numbers in the GDNF-enriched area, as compared with those in the GDNF-low/negative area of the seminiferous tubules. CONCLUSION/SIGNIFICANCE: Our data provide direct evidence of regionally defined patch-like GDNF-positive signal site in which GFRα1-positive spermatogonia possibly interact with GDNF in the basal compartment of the seminiferous tubules

Gene expression profiling of rat spermatogonia and Sertoli cells reveals signaling pathways from stem cells to niche and testicular cancer cells to surrounding stroma

Background: Stem cells and their niches are studied in many systems, but mammalian germ stem cells (GSC) and their niches are still poorly understood. In rat testis, spermatogonia and undifferentiated Sertoli cells proliferate before puberty, but at puberty most spermatogonia enter spermatogenesis, and Sertoli cells differentiate to support this program. Thus, pre-pubertal spermatogonia might possess GSC potential and pre-pubertal Sertoli cells niche functions. We hypothesized that the different stem cell pools at pre-puberty and maturity provide a model for the identification of stem cell and niche-specific genes. We compared the transcript profiles of spermatogonia and Sertoli cells from pre-pubertal and pubertal rats and examined how these related to genes expressed in testicular cancers, which might originate from inappropriate communication between GSCs and Sertoli cells. Results: The pre-pubertal spermatogonia-specific gene set comprised known stem cell and spermatogonial stem cell (SSC) markers. Similarly, the pre-pubertal Sertoli cell-specific gene set comprised known niche gene transcripts. A large fraction of these specifically enriched transcripts encoded trans-membrane, extra-cellular, and secreted proteins highlighting stem cell to niche communication. Comparing selective gene sets established in this study with published gene expression data of testicular cancers and their stroma, we identified sets expressed genes shared between testicular tumors and pre-pubertal spermatogonia, and tumor stroma and pre-pubertal Sertoli cells with statistic significance. Conclusions: Our data suggest that SSC and their niche specifically express complementary factors for cell communication and that the same factors might be implicated in the communication between tumor cells and their micro-enviroment in testicular cancer

The Syk Kinase SmTK4 of Schistosoma mansoni Is Involved in the Regulation of Spermatogenesis and Oogenesis

The signal transduction protein SmTK4 from Schistosoma mansoni belongs to the family of Syk kinases. In vertebrates, Syk kinases are known to play specialized roles in signaling pathways in cells of the hematopoietic system. Although Syk kinases were identified in some invertebrates, their role in this group of animals has not yet been elucidated. Since SmTK4 is the first Syk kinase from a parasitic helminth, shown to be predominantly expressed in the testes and ovary of adult worms, we investigated its function. To unravel signaling cascades in which SmTK4 is involved, yeast two-/three-hybrid library screenings were performed with either the tandem SH2-domain, or with the linker region including the tyrosine kinase domain of SmTK4. Besides the Src kinase SmTK3 we identified a new Src kinase (SmTK6) acting upstream of SmTK4 and a MAPK-activating protein, as well as mapmodulin acting downstream. Their identities and colocalization studies pointed to a role of SmTK4 in a signaling cascade regulating the proliferation and/or differentiation of cells in the gonads of schistosomes. To confirm this decisive role we performed biochemical and molecular approaches to knock down SmTK4 combined with a novel protocol for confocal laser scanning microscopy for morphological analyses. Using the Syk kinase-specific inhibitor Piceatannol or by RNAi treatment of adult schistosomes in vitro, corresponding phenotypes were detected in the testes and ovary. In the Xenopus oocyte system it was finally confirmed that Piceatannol suppressed the activity of the catalytic kinase domain of SmTK4. Our findings demonstrate a pivotal role of SmTK4 in gametogenesis, a new function for Syk kinases in eukaryotes