Suchergebnisse

If misregulated, macrophage (M)T cell interactions can drive chronic inflammation thereby causing diseases, such as rheumatoid arthritis (RA). We report that in a proinflammatory environment, granulocyte-M (GM-CSF)- and M colony-stimulating factor (M-CSF)-dependent Ms have dichotomous effects on T cell activity. While GM-CSF-dependent Ms show a highly stimulatory activity typical for M1 Ms, M-CSF-dependent Ms, marked by folate receptor (FR), adopt an immunosuppressive M2 phenotype. We find the latter to be caused by the purinergic pathway that directs release of extracellular ATP and its conversion to immunosuppressive adenosine by co-expressed CD39 and CD73. Since we observed a misbalance between immunosuppressive and immunostimulatory Ms in human and murine arthritic joints, we devised a new strategy for RA treatment based on targeted delivery of a novel methotrexate (MTX) formulation to the immunosuppressive FR+CD39+CD73+ Ms, which boosts adenosine production and curtails the dominance of proinflammatory Ms. In contrast to untargeted MTX, this approach leads to potent alleviation of inflammation in the murine arthritis model. In conclusion, we define the M extracellular purine metabolism as a novel checkpoint in M cell fate decision-making and an attractive target to control pathological Ms in immune-mediated diseases. ; The research leading to these results has received funding from the European Union's Horizon 2020 Research and Innovation Program under grant agreement No 683356 - FOLSMART and from the Seventh Framework Program (FP7/2007-2013) under grant agreement NMP4-LA-2009-228827 NANOFOL. RP was supported by the Boehringer Ingelheim Fonds and the Ph.D. program Cell Communication in Health and Disease supported by the Austrian Science Fund (FWF). VL was supported by the FWF (P22908), VEGA (2/0063/14), and APVV (16-0452). JH received support from the Vienna Science and Technology Fund (WWTF) LS14-031. ...

Methotrexate is the first line of treatment of rheumatoid arthritis. Since many patients become unresponsive to methotrexate treatment, only very expensive biological therapies are effective and increased methotrexate tolerance strategies need to be identified. Here we propose the encapsulation of methotrexate in a new liposomal formulation using a hydrophobic fragment of surfactant protein conjugated to a linker and folate to enhance their tolerance and efficacy. In this study we aim to evaluate the efficiency of this system to treat rheumatoid arthritis, by targeting folate receptor present at the surface of activated macrophages, key effector cells in this pathology. The specificity of our liposomal formulation to target folate receptor was investigated both in vitro as in vivo using a mouse model of arthritis (collagen-induced arthritis in DBA/1J mice strain). In both systems, the liposomal constructs were shown to be highly specific and efficient in targeting folate receptor . These liposomal formulations also significantly increase the clinical benefit of the encapsulated methotrexate in vivo in arthritic mice, together with reduced expression of CD39 and CD73 ectonucleotidases by joint-infiltrating macrophages. Thus, our formulation might be a promising cost effective way to treat rheumatoid arthritis and delay or reduce methotrexate intolerance. ; Eugenia Nogueira (SFRH/BD/81269/2011), Ana Loureiro (SFRH/BD/81479/2011) and Catarina Almeida (SFRH/BPD/48533/2008) hold scholarships from Fundacao para a Ciencia e a Tecnologia (FCT). Goncalo J. L. Bernardes is a Royal Society University Research Fellow at the Department of Chemistry, University of Cambridge and an Investigador FCT at the Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa. This study was funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement NMP4-LA-2009-228827 NANOFOL. This study was also supported by FEDER through POFC-COMPETE, by national funds from FCT through the ...