Three-Dimensional Study of Polymer Composite Destruction in the Early Stages.

The investigation of destruction processes in composite materials is a current problem for their structural application and the improvement of their functional properties. This work aimed to visualize structural changes induced in layered carbon fiber reinforced plastics (CFRP) with the help of synchrotron X-ray microtomography. This article presents the details of destructive processes in the early stages of the deformation of reinforced polymers under uniaxial stretching, investigated at the micro level. Individual structural elements of the composite-filaments, parallel fiber bundles, the nonuniformity of the polymer binder distribution, and continuity defects-were observed under an external load. We have considered the influence of the material architecture and technological defects on fracture evolution in cross-ply and quasi-isotropic fiber-reinforced plastics. The results indicate the sequence of irreversible structural changes before the destruction of the material.

Integrative Development of a TLR8 Agonist for Ovarian Cancer Chemoimmunotherapy.

Purpose: Immunotherapy is an emerging paradigm for the treatment of cancer, but the potential efficacy of many drugs cannot be sufficiently tested in the mouse. We sought to develop a rational combination of motolimod-a novel Toll-like receptor 8 (TLR8) agonist that stimulates robust innate immune responses in humans but diminished responses in mice-with pegylated liposomal doxorubicin (PLD), a chemotherapeutic that induces immunogenic cell death.Experimental Design: We followed an integrative pharmacologic approach including healthy human volunteers, non-human primates, NSG-HIS ("humanized immune system") mice reconstituted with human CD34+ cells, and patients with cancer to test the effects of motolimod and to assess the combination of motolimod with PLD for the treatment of ovarian cancer.Results: The pharmacodynamic effects of motolimod monotherapy in NSG-HIS mice closely mimicked those in non-human primates and healthy human subjects, whereas the effects of the motolimod/PLD combination in tumor-bearing NSG-HIS mice closely mimicked those in patients with ovarian cancer treated in a phase Ib trial (NCT01294293). The NSG-HIS mouse helped elucidate the mechanism of action of the combination and revealed a positive interaction between the two drugs in vivo The combination produced no dose-limiting toxicities in patients with ovarian cancer. Two subjects (15%) had complete responses and 7 subjects (53%) had disease stabilization. A phase II study was consequently initiated.Conclusions: These results are the first to demonstrate the value of pharmacologic approaches integrating the NSG-HIS mouse, non-human primates, and patients with cancer for the development of novel immunomodulatory anticancer agents with human specificity. Clin Cancer Res; 23(8); 1955-66. ©2016 AACR.

Bacillus anthracis peptidoglycan stimulates an inflammatory response in monocytes through the p38 mitogen-activated protein kinase pathway.

We hypothesized that the peptidoglycan component of B. anthracis may play a critical role in morbidity and mortality associated with inhalation anthrax. To explore this issue, we purified the peptidoglycan component of the bacterial cell wall and studied the response of human peripheral blood cells. The purified B. anthracis peptidoglycan was free of non-covalently bound protein but contained a complex set of amino acids probably arising from the stem peptide. The peptidoglycan contained a polysaccharide that was removed by mild acid treatment, and the biological activity remained with the peptidoglycan and not the polysaccharide. The biological activity of the peptidoglycan was sensitive to lysozyme but not other hydrolytic enzymes, showing that the activity resides in the peptidoglycan component and not bacterial DNA, RNA or protein. B. anthracis peptidoglycan stimulated monocytes to produce primarily TNFalpha; neutrophils and lymphocytes did not respond. Peptidoglycan stimulated monocyte p38 mitogen-activated protein kinase and p38 activity was required for TNFalpha production by the cells. We conclude that peptidoglycan in B. anthracis is biologically active, that it stimulates a proinflammatory response in monocytes, and uses the p38 kinase signal transduction pathway to do so. Given the high bacterial burden in pulmonary anthrax, these findings suggest that the inflammatory events associated with peptidoglycan may play an important role in anthrax pathogenesis.

IL-6 blocks a discrete early step in lymphopoiesis.

Animals lacking Src homology 2 domain-containing inositol 5-phosphatase (SHIP) display a reduction in lymphopoiesis and a corresponding enhancement of myelopoiesis. These effects are mediated at least in part by elevated levels of interleukin 6 (IL-6). Here, we show the lymphopoiesis block in SHIP-/- mice is due to suppression of the lymphoid lineage choice by uncommitted progenitors. The suppression can be reproduced in vitro with recombinant IL-6, and IL-6 acts directly on hematopoietic progenitors. The block is partially overcome in SHIP-/- IL-6-/- double-deficient animals. IL-6 does not suppress but actually enhances proliferation of lymphoid-committed progenitors, indicating the IL-6 target cells are hematopoietic stem cells or multipotent progenitors. The findings suggest a mechanism for the lymphopenia that accompanies proinflammatory diseases.

Src homology 2-containing 5-inositol phosphatase (SHIP) suppresses an early stage of lymphoid cell development through elevated interleukin-6 production by myeloid cells in bone marrow.

The Src homology (SH)2-containing inositol 5-phosphatase (SHIP) negatively regulates a variety of immune responses through inhibitory immune receptors. In SHIP(-/-) animals, we found that the number of early lymphoid progenitors in the bone marrow was significantly reduced and accompanied by expansion of myeloid cells. We exploited an in vitro system using hematopoietic progenitors that reproduced the in vivo phenotype of SHIP(-/-) mice. Lineage-negative marrow (Lin(-)) cells isolated from wild-type mice failed to differentiate into B cells when cocultured with those of SHIP(-/-) mice. Furthermore, culture supernatants of SHIP(-/-) Lin(-) cells suppressed the B lineage expansion of wild-type lineage-negative cells, suggesting the presence of a suppressive cytokine. SHIP(-/-) Lin(-) cells contained more IL-6 transcripts than wild-type Lin(-) cells, and neutralizing anti-IL-6 antibody rescued the B lineage expansion suppressed by the supernatants of SHIP(-/-) Lin(-) cells. Finally, we found that addition of recombinant IL-6 to cultures of wild-type Lin(-) bone marrow cells reproduced the phenotype of SHIP(-/-) bone marrow cultures: suppression of B cell development and expansion of myeloid cells. The results identify IL-6 as an important regulatory cytokine that can suppress B lineage differentiation and drive excessive myeloid development in bone marrow.

The Src homology 2 domain-containing inositol 5-phosphatase negatively regulates Fcgamma receptor-mediated phagocytosis through immunoreceptor tyrosine-based activation motif-bearing phagocytic receptors.

Molecular mechanisms by which the Src homology 2 domain-containing inositol 5-phosphatase (SHIP) negatively regulates phagocytosis in macrophages are unclear. We addressed the issue using bone marrow-derived macrophages from FcgammaR- or SHIP-deficient mice. Phagocytic activities of macrophages from FcgammaRII(b)(-/-) and SHIP(-/-) mice were enhanced to a similar extent, relative to those from wild type. However, calcium influx was only marginally affected in FcgammaRII(b)(-/-), but greatly enhanced in SHIP(-/-) macrophages. Furthermore, SHIP was phosphorylated on tyrosine residues upon FcgammaR aggregation even in macrophages from FcgammaRII(b)(-/-) mice or upon clustering of a chimeric receptor containing CD8 and the immunoreceptor tyrosine-based activation motif (ITAM)-bearing gamma-chain or human-restricted FcgammaRIIa. These findings indicate that, unlike B cells, SHIP is efficiently phosphorylated in the absence of an immunoreceptor tyrosine-based inhibition motif (ITIM)-bearing receptor. We further demonstrate that SHIP directly bound to phosphorylated peptides derived from FcgammaRIIa with a high affinity, comparable to that of FcgammaRII(b). Lastly, FcgammaRIIa-mediated phagocytosis was significantly enhanced in THP-1 cells overexpressing dominant-negative form of SHIP in the absence of FcgammaRII(b). These results indicate that SHIP negatively regulates FcgammaR-mediated phagocytosis through all ITAM-containing IgG receptors using a molecular mechanism distinct from that in B cells.