Early Production of IL-22 but Not IL-17 by Peripheral Blood Mononuclear Cells Exposed to live Borrelia burgdorferi: The Role of Monocytes and Interleukin-1

If insufficiently treated, Lyme borreliosis can evolve into an inflammatory disorder affecting skin, joints, and the CNS. Early innate immunity may determine host responses targeting infection. Thus, we sought to characterize the immediate cytokine storm associated with exposure of PBMC to moderate levels of live Borrelia burgdorferi. Since Th17 cytokines are connected to host defense against extracellular bacteria, we focused on interleukin (IL)-17 and IL-22. Here, we report that, despite induction of inflammatory cytokines including IL-23, IL-17 remained barely detectable in response to B. burgdorferi. In contrast, T cell-dependent expression of IL-22 became evident within 10 h of exposure to the spirochetes. This dichotomy was unrelated to interferon-γ but to a large part dependent on caspase-1 and IL-1 bioactivity derived from monocytes. In fact, IL-1β as a single stimulus induced IL-22 but not IL-17. Neutrophils display antibacterial activity against B. burgdorferi, particularly when opsonized by antibodies. Since neutrophilic inflammation, indicative of IL-17 bioactivity, is scarcely observed in Erythema migrans, a manifestation of skin inflammation after infection, protective and antibacterial properties of IL-22 may close this gap and serve essential functions in the initial phase of spirochete infection

Nanostructured monticellite for tissue engineering applications � Part II: Molecular and biological characteristics

Silicon (Si)- and magnesium (Mg)-containing bioceramics have recently gained much attention for tissue engineering applications due to their ability to stimulate cell proliferation and differentiation along with their adequate microstructural and physicochemical characteristics. In this study, nanostructured monticellite (CaMgSiO4, 33.33 of Mg) was chosen as an appealing biomaterial to identify time- and dose-dependent cytocompatibility, in vitro osteogenic activity and antibacterial & anti-biofilm activity. A time- and dose-dependent MTT assay illustrated that monticellite nanoparticles promoted proliferation of bone like cell considerably more than positive and negative controls. The cell viability of the bioceramic was higher than hydroxyapatite (HA, as bone inorganic material) and control sample, demonstrating that cytocompatibility was promoted due to the increase of Mg content. The results of alkaline phosphatase (ALP) activity test demonstrated that the osteogenic proliferation of osteoblast-like G292 cell line enhanced more by the bioceramics extract than control and HA, corroborating when Mg content of the calcium-silicate bioceramics is increased cytocompatibility and bioactivity are significantly promoted. Moreover, further analyses revealed that the bioceramic possessed antibacterial and anti-biofilm properties due to the presence of Mg, Si and Ca elements in the structure. These findings suggest that the proposed nanostructured monticellite is a promising biomaterial for further applications in tissue engineering. © 2018 Elsevier Ltd and Techna Group S.r.l

Nanostructured monticellite for tissue engineering applications - Part I: Microstructural and physicochemical characteristics

In this study, nanostructured monticellite (CaMgSiO4) bioceramics were prepared via sintering the sol�gel-derived monticellite powder compacts at 1200 °C. The mean of particles size distribution of the synthesized monticellite powders was approximately 90 nm. After evaluating physicochemical characteristics of the synthesized bioceramics, apatite-forming ability of the samples were examined in simulated body fluid (SBF) for different time periods. The soaking effect of various time periods on the X-ray diffraction (XRD) patterns, followed by the calculations from scherrer's equation, showed that the crystallite size of the immersed monticellite ceramics in SBF for 3 and 7 days was around 88 nm. Williamson-Hall analysis was also used to calculate the lattice strain of the samples. Based on the results, by changing the soaking time, crystallite size and lattice strain have meaningfully changed. The release of Ca, Mg and Si ions from the nanostructured monticellite significantly promoted cell proliferation and growth at a certain concentration range more than that of positive and negative controls. This study could provide an in-depth understanding of the microstructural and physicochemical characteristics of this class of biomaterials. The follow-up studies should correlate the microstructural and physicochemical properties to the molecular and biological characteristics for applications in tissue engineering and regenerative medicine. © 2018 Elsevier Ltd and Techna Group S.r.l

Nanostructured monticellite for tissue engineering applications - Part I: Microstructural and physicochemical characteristics

In this study, nanostructured monticellite (CaMgSiO4) bioceramics were prepared via sintering the sol�gel-derived monticellite powder compacts at 1200 °C. The mean of particles size distribution of the synthesized monticellite powders was approximately 90 nm. After evaluating physicochemical characteristics of the synthesized bioceramics, apatite-forming ability of the samples were examined in simulated body fluid (SBF) for different time periods. The soaking effect of various time periods on the X-ray diffraction (XRD) patterns, followed by the calculations from scherrer's equation, showed that the crystallite size of the immersed monticellite ceramics in SBF for 3 and 7 days was around 88 nm. Williamson-Hall analysis was also used to calculate the lattice strain of the samples. Based on the results, by changing the soaking time, crystallite size and lattice strain have meaningfully changed. The release of Ca, Mg and Si ions from the nanostructured monticellite significantly promoted cell proliferation and growth at a certain concentration range more than that of positive and negative controls. This study could provide an in-depth understanding of the microstructural and physicochemical characteristics of this class of biomaterials. The follow-up studies should correlate the microstructural and physicochemical properties to the molecular and biological characteristics for applications in tissue engineering and regenerative medicine. © 2018 Elsevier Ltd and Techna Group S.r.l

Expression of inflammasome proteins and inflammasome activation occurs in human, but not in murine keratinocytes

Inflammasomes are multimeric protein complexes that assemble upon sensing of a variety of stress factors. Their formation results in caspase-1-mediated activation and secretion of the pro-inflammatory cytokines pro-interleukin(IL)-1β and -18, which induce an inflammatory response. Inflammation is supported by a lytic form of cell death, termed pyroptosis. Innate immune cells, such as macrophages or dendritic cells, express and activate inflammasomes. However, it has also been demonstrated that human primary keratinocytes activate different types of inflammasomes in vitro, for example, upon UVB irradiation or viral infection. Keratinocytes are the main cell type of the epidermis, the outermost layer of the body, and form a protective barrier consisting of a stratified multi-layered epithelium. In human, gain-of-function mutations of the NLRP1 gene cause syndromes mediated by inflammasome activation in keratinocytes that are characterised by skin inflammation and skin cancer susceptibility. Here we demonstrate that murine keratinocytes do not activate inflammasomes in response to stimuli, which induce IL-1β and -18 secretion by human keratinocytes. Whereas murine keratinocytes produced caspase-1 and proIL-18, expression of the inflammasome proteins Nlrp1, Nlrp3, Aim2, Asc, and proIL-1β was, compared to human keratinocytes or murine dendritic cells, very low or even undetectable. Priming of murine keratinocytes with cytokines commonly used for induction of proIL-1β and inflammasome protein expression did not rescue inflammasome activation. Nevertheless, UVB-induced inflammation and neutrophil recruitment in murine skin was dependent on IL-1β and caspase-1. However, also under these conditions, we did not detect expression of proIL-1β by keratinocytes in murine skin, but by immune cells. These results demonstrate a higher immunological competence of human compared to murine keratinocytes, which is reflected by stress-induced IL-1β secretion that is mediated by inflammasomes. Therefore, keratinocytes in human skin can exert immune functions, which are carried out by professional immune cells in murine skin