Microparticles are small membrane vesicles released from the cell membrane by exogenous budding. To elucidate the interactions of microparticles with macrophages, the effect of microparticles released from Jurkat T cells on RAW 264.7 cells was determined. Microparticles were isolated by differential centrifugation, using FACS analysis with annexin V and cell surface markers for identification. Various inducers of apoptosis increased the release of microparticles from Jurkat cells up to 5-fold. The released microparticles were then cultured with RAW 264.7 cells. As shown by confocal microscopy and FACS analysis, RAW 264.7 macrophages cleared microparticles by phagocytosis. In addition, microparticles induced apoptosis in RAW 264.7 cells in a dose-dependent manner with up to a 5-fold increase of annexin V positive cells and 9-fold increase in caspase 3 activity. Cell proliferation as determined by the MTT test was also reduced. Furthermore, microparticles stimulated the release of microparticles from macrophages. These effects were specific for macrophages, since no apoptosis was observed in NIH 3T3 and L929 cells. These findings indicate that microparticles can induce macrophages to undergo apoptosis, in turn resulting in a further increase of microparticles. The release of microparticles from apoptotic cells may therefore represent a novel amplification loop of cell death.

Behçet’s disease (BD) activity is characterised by sustained, over-exuberant immune activation, yet the underlying mechanisms leading to active BD state are poorly defined. Herein, we show that the human cathelicidin derived antimicrobial peptide LL37 associates with and directs plasma extracellular vesicles (EV) to immune cells, thereby leading to enhanced immune activation aggravating BD pathology. Notably, disease activity was correlated with elevated levels of circulating LL37 and EV plasma concentration. Stimulation of healthy PBMC with active BD patient EVs induced heightened IL1β, IFNα, IL6 and IP10 secretion compared to healthy and inactive BD EVs. Remarkably, when mixed with LL37, healthy plasma-EVs triggered a robust immune activation replicating the pathology inducing properties of BD EVs. The findings of this study could be of clinical interest in the management of BD, implicating LL37/EV association as one of the major contributors of BD pathogenesis. Abbreviations: BD: Behçet’s disease; EV: extracellular vesicle; BB: binding buffer; AnV: annexin V; autologEV: autologous extracellular vesicles; alloEV: allogeneic extracellular vesicles

Activation of the immune system and increased synthesis of extracellular matrix proteins by fibroblasts are hallmarks in the pathogenesis of systemic sclerosis (SSc). The mechanisms that initiate the accumulation of inflammatory cells are still unknown. Chemokines are a family of small molecules that are divided into subfamilies according to the position of NH 2 -terminal cysteine motif. A new nomenclature for chemokines recently has been introduced in an attempt to overcome the confusion resulting from a number of different names for the same chemokines. Recent data indicate that chemokines, and in particular MCP-1 (CCL2), might be involved in the pathogenesis of SSc at different levels. MCP-1 is highly upregulated in skin specimens from SSc patients compared with those from healthy controls. Dermal fibroblasts release MCP-1, which is able to induce and perpetuate the migration of inflammatory cells into the skin. Interestingly, data from animal models, as well as from in vitro studies, indicate that MCP-1 might also be involved in the increased synthesis of extracellular matrix proteins, by either direct or indirect mechanisms. In conclusion, chemokines represent interesting candidates for target-directed therapies for SSc. This concept has to be confirmed by further studies using animal models for SSc and other fibrotic diseases.

Unser Forschungszentrum beschäftigte sich über die letzte Dekade intensiv mit den epigenetischen Regulationen der Expression von Genen. Zu diesen regulatorischen Prozessen gehört auch die Modulation durch microRNAs. Man darf in diesem Zusammenhang aber nicht übersehen, dass microRNAs sowohl durch Acetylierung als auch Methylierung reguliert werden [1]. Fakt ist, dass wir trotz der Anwendung neuer anti-rheumatischer Medikamente, hier müssen besonders die äußerst effektiven "Biologicals" genannt werden, die Rheumatoide Arthritis (RA) oder progressive systemische Sklerose bisher nicht heilen können. Das liegt an der Tatsache, dass die synovialen Fibroblasten (SF) bei der RA bisher nur als Effektorzellen betrachtet wurden und nicht als aktivierte krankheitsunterhaltende Zellen therapeutisch angegangen wurden [2]. Das gleiche trifft für die Fibroblasten bei den fibrosierenden Erkrankungen zu. In der Suche nach neuen therapeutischen Ansätzen haben wir uns deshalb in den letzten Jahren auch besonders den microRNAs (miR) zugewendet [3, 4]. So konnten wir zuerst zeigen, dass miR146a und miR155 in RASF und besonders miR155 auch in Monozyten stark exprimiert werden [5] und als proinflammatorischer Regulator in Arthritismodellen fungiert [6]. Wir konnten ferner nachweisen, dass miRs wie miR203 entscheidend die inflammatorischen Zytokine wie IL6 in RASF stimuliert und selbst durch Demethylierung induziert wird [7]. Wie komplex die Regulation dieser Prozesse ist, zeigt, dass miR18a nicht nur die IL6-induzierte Produktion von den Akute-Phase-Proteinen Fibrinogen und Haptoglobin in humanen Hepatozyten reguliert [8], sondern selbst durch TNFα induziert wird und dabei RASF durch einen Feedback-loop im NFκB-Signaling aktiviert [9]. Den miRs kommt auch entwicklungsbiologisch eine wichtige Funktion zu. So konnten wir in kooperativen Untersuchungen mit der ETH in Zürich nachweisen, dass die Funktion der Desmosomen in Keratinozyten durch die Nrf2-miR29-desmocollin axis reguliert wird [10]. Dass antago-miRs auch therapeutisch eingesetzt werden können, konnten wir in einem Modell der Hypoxie-induzierten pulmonalen Hypertrophie beweisen [11]. Besonders attraktiv erscheint der geplante therapeutische Einsatz von antago-miR323, denn wir konnten miR323 als Regulator von TIMP3 nachweisen. TIMP3 kommt eine entscheidende Rolle in der Hemmung der Aktivierung der proinflammatorischen Zytokine IL6 und TNFα zu.

Child protection systems in Australia are struggling to cope with the growing number of children requiring out-of-home care because of abuse or neglect occurring within families. Professionals and governments are grappling with the alternative care options that are available in an attempt to improve children’s health, education and emotional development. Research demonstrates that children suffer if they are exposed to multiple placements throughout childhood and this leads some to believe that the permanency of adoption would better serve the needs of children from broken families. This article considers the recent proposal by the South Australian State Coroner to expand the role of adoption as a child protection response, noting that New South Wales introduced such a model in 2014. It also examines international approaches in this area as well as the findings of studies into foster care and adoption. By drawing together the knowledge gained from different policy and practice approaches to out-of-home care, this article argues that introducing a blanket approach favouring adoption is not an appropriate option. It concludes that the only model likely to achieve the best outcomes for children is one involving individual responses to every child.