Alternatively activated macrophages promote pancreatic fibrosis in chronic pancreatitis.

Chronic pancreatitis (CP) is a progressive and irreversible inflammatory and fibrotic disease with no cure. Unlike acute pancreatitis (AP), we find that alternatively activated macrophages (AAMs) are dominant in mouse and human CP. AAMs are dependent on interleukin (IL)-4 and IL-13 signalling, and we show that mice lacking IL-4Rα, myeloid-specific IL-4Rα and IL-4/IL-13 were less susceptible to pancreatic fibrosis. Furthermore, we demonstrate that mouse and human pancreatic stellate cells (PSCs) are a source of IL-4/IL-13. Notably, we show that pharmacologic inhibition of IL-4/IL-13 in human ex vivo studies as well as in established mouse CP decreases pancreatic AAMs and fibrosis. We identify a critical role for macrophages in pancreatic fibrosis and in turn PSCs as important inducers of macrophage-alternative activation. Our study challenges and identifies pathways involved in crosstalk between macrophages and PSCs that can be targeted to reverse or halt pancreatic fibrosis progression

Vascular niche IL-6 induces alternative macrophage activation in glioblastoma through HIF-2α.

Spatiotemporal regulation of tumor immunity remains largely unexplored. Here we identify a vascular niche that controls alternative macrophage activation in glioblastoma (GBM). We show that tumor-promoting macrophages are spatially proximate to GBM-associated endothelial cells (ECs), permissive for angiocrine-induced macrophage polarization. We identify ECs as one of the major sources for interleukin-6 (IL-6) expression in GBM microenvironment. Furthermore, we reveal that colony-stimulating factor-1 and angiocrine IL-6 induce robust arginase-1 expression and macrophage alternative activation, mediated through peroxisome proliferator-activated receptor-γ-dependent transcriptional activation of hypoxia-inducible factor-2α. Finally, utilizing a genetic murine GBM model, we show that EC-specific knockout of IL-6 inhibits macrophage alternative activation and improves survival in the GBM-bearing mice. These findings illustrate a vascular niche-dependent mechanism for alternative macrophage activation and cancer progression, and suggest that targeting endothelial IL-6 may offer a selective and efficient therapeutic strategy for GBM, and possibly other solid malignant tumors

Reduced Necrosis and Content of Apoptotic M1 Macrophages in Advanced Atherosclerotic Plaques of Mice With Macrophage-Specific Loss of Trpc3

In previous work we reported that ApoeKO mice transplanted with bone marrow cells deficient in the Transient Receptor Potential Canonical 3 (TRPC3) channel have reduced necrosis and number of apoptotic macrophages in advanced atherosclerotic plaques. Also, in vitro studies with polarized macrophages derived from mice with macrophage-specific loss of TRPC3 showed that M1, but not M2 macrophages, deficient in Trpc3 are less susceptible to ER stress-induced apoptosis than Trpc3 expressing cells. The questions remained (a) whether the plaque phenotype in transplanted mice resulted from a genuine effect of Trpc3 on macrophages, and (b) whether the reduced necrosis and macrophage apoptosis in plaques of these mice was a manifestation of the selective effect of TRPC3 on apoptosis of M1 macrophages previously observed in vitro. Here, we addressed these questions using Ldlr knockout (Ldlr−/−) mice with macrophage-specific loss of Trpc3 (MacTrpc3−/−/Ldlr−/− → Ldlr−/−). Compared to controls, we observed decreased plaque necrosis and number of apoptotic macrophages in MacTrpc3−/−/Ldlr−/− → Ldlr−/− mice. Immunohistochemical analysis revealed a reduction in apoptotic M1, but not apoptotic M2 macrophages. These findings confirm an effect of TRPC3 on plaque necrosis and support the notion that this is likely a reflection of the reduced susceptibility of Trpc3-deficient M1 macrophages to apoptosis.Fil: Solanki, Sumeet. University of Toledo; Estados UnidosFil: Dube, Prabhatchandra R.. University of Toledo; Estados UnidosFil: Birnbaumer, Lutz. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Vazquez, Guillermo. University of Toledo; Estados Unido

Dectin-1 Activation Exacerbates Obesity and Insulin Resistance in the Absence of MyD88

This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, grant numbers 11/15682-4, 12/02270-2, 15/18121-4), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Regenera INCT Process Grant 465656/2014-5). JL is funded by the NIH/NIDDK R01DK106210. GDB is funded by the Wellcome Trust and the MRC Centre for Medical Mycology. Open access journalPeer reviewedPublisher PD

Immune cell census in murine atherosclerosis: cytometry by time of flight illuminates vascular myeloid cell diversity

Aims: Atherosclerosis is characterised by the abundant infiltration of myeloid cells starting at early stages of disease. Myeloid cells are key players in vascular immunity during atherogenesis. However, the subsets of vascular myeloid cells have eluded resolution due to shared marker expression and atypical heterogeneity in vascular tissues. We applied the high-dimensionality of mass cytometry to the study of myeloid cell subsets in atherosclerosis. Methods and Results: Apolipoprotein E-deficient (ApoE-/-) mice were fed a chow or a high fat (western) diet for 12 weeks. Single cell aortic preparations were probed with a panel of 35 metal-conjugated antibodies using Cytometry by time of flight (CyTOF). Clustering of marker expression on live CD45+ cells from the aortas of ApoE-/- mice identified 13 broad populations of leucocytes. Monocyte, macrophage, type 1 and type 2 conventional dendritic cell (cDC1 and cDC2), plasmacytoid dendritic cell (pDC), neutrophil, eosinophil, B cell, CD4+ and CD8+ T cell, γδ T cell, natural killer (NK) cell and innate lymphoid (ILC) cell populations accounted for approximately 95% of the live CD45+ aortic cells. Automated clustering algorithms applied to the Lin-CD11blo-hi cells revealed 20 clusters of myeloid cells. Comparison between chow and high fat fed animals revealed increases in monocytes (both Ly6C+ and Ly6C-), pDC and a CD11c+ macrophage subset with high fat feeding. Concomitantly, the proportions of CD206+ CD169+ subsets of macrophages were significantly reduced as were cDC2. Conclusions: A CyTOF-based comprehensive mapping of the immune cell subsets within atherosclerotic aortas from ApoE-/- mice offers tools for myeloid cell discrimination within the vascular compartment and it reveals that high fat feeding skews the myeloid cell repertoire towards inflammatory monocyte-macrophage populations rather than resident macrophage phenotypes and cDC2 during atherogenesis

Platelets promote macrophage polarization toward pro-inflammatory phenotype and increase survival of septic mice

We investigated the contribution of human platelets to macrophage effector properties in the presence of lipopolysaccharide (LPS), as well as the beneficial effects and time frame for platelet transfusion in septic animals. Our results show that platelets sequester both pro-(TNF-α/IL-6) and anti-(IL-10) inflammatory cytokines released by monocytes. Low LPS concentrations (0.01 ng/mL) induced M2 macrophage polarization by decreasing CD64 and augmenting CD206 and CD163 expression; yet, the presence of platelets skewed monocytes toward type 1 macrophage (M1) phenotype in a cell-contact-dependent manner by the glycoprotein Ib (GPIb)-CD11b axis. Accordingly, platelet-licensed macrophages showed increased TNF-α levels, bacterial phagocytic activity, and a reduced healing capability. Platelet transfusion increased inducible nitric oxide synthase (iNOS)+ macrophages, improving bacterial clearance and survival rates in septic mice up to 6 h post-infection, an effect that was abolished by CD11b and GPIb blockade. Our results demonstrate that platelets orchestrate macrophage effector responses, improving the clinical outcome of sepsis in a narrow but relevant time frame.Fil: Carestia, Agostina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. University of Calgary; CanadáFil: Mena, Hebe Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Olexen, Cinthia Mariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Ortiz Wilczyñski, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Negrotto, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Errasti, Andrea Emilse. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Farmacologia; ArgentinaFil: Gomez, Ricardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Jenne, Craig N.. University of Calgary; CanadáFil: Carrera Silva, Eugenio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Schattner, Mirta Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Spatial Distribution of Macrophages During Callus Formation and Maturation Reveals Close Crosstalk Between Macrophages and Newly Forming Vessels

Macrophages are essential players in the process of fracture healing, acting by remodeling of the extracellular matrix and enabling vascularization. Whilst activated macrophages of M1-like phenotype are present in the initial pro-inflammatory phase of hours to days of fracture healing, an anti-inflammatory M2-like macrophage phenotype is supposed to be crucial for the induction of downstream cascades of healing, especially the initiation of vascularization. In a mouse-osteotomy model, we provide a comprehensive characterization of vessel (CD31+, Emcn+) and macrophage phenotypes (F4/80, CD206, CD80, Mac-2) during the process of fracture healing. To this end, we phenotype the phases of vascular regeneration-the expansion phase (d1-d7 after injury) and the remodeling phase of the endothelial network, until tissue integrity is restored (d14-d21 after injury). Vessels which appear during the bone formation process resemble type H endothelium (CD31hiEmcnhi), and are closely connected to osteoprogenitors (Runx2+, Osx+) and F4/80+ macrophages. M1-like macrophages are present in the initial phase of vascularization until day 3 post osteotomy, but they are rare during later regeneration phases. M2-like macrophages localize mainly extramedullary, and CD206+ macrophages are found to express Mac-2+ during the expansion phase. VEGFA expression is initiated by CD80+ cells, including F4/80+ macrophages, until day 3, while subsequently osteoblasts and chondrocytes are main contributors to VEGFA production at the fracture site. Using Longitudinal Intravital Microendoscopy of the Bone (LIMB) we observe changes in the motility and organization of CX3CR1+ cells, which infiltrate the injury site after an osteotomy. A transient accumulation, resulting in spatial polarization of both, endothelial cells and macrophages, in regions distal to the fracture site, is evident. Immunofluorescence histology followed by histocytometric analysis reveals that F4/80+CX3CR1+ myeloid cells precede vascularization

Bisdemethoxycurcumin and Its Cyclized Pyrazole Analogue Differentially Disrupt Lipopolysaccharide Signalling in Human Monocyte-Derived Macrophages

open11noSeveral studies suggest that curcumin and related compounds possess antioxidant and anti-inflammatory properties including modulation of lipopolysaccharide- (LPS-) mediated signalling in macrophage cell models. We here investigated the effects of curcumin and the two structurally unrelated analogues GG6 and GG9 in primary human blood-derived macrophages as well as the signalling pathways involved. Macrophages differentiated from peripheral blood monocytes for 7 days were activated with LPS or selective Toll-like receptor agonists for 24 h. The effects of test compounds on cytokine production and immunophenotypes evaluated as CD80+/CCR2+ and CD206+/CD163+ subsets were examined by ELISA and flow cytometry. Signalling pathways were probed by Western blot. Curcumin (2.5–10 μM) failed to suppress LPS-induced inflammatory responses. While GG6 reduced LPS-induced IκB-α degradation and showed a trend towards reduced interleukin-1β release, GG9 prevented the increase in proinflammatory CD80+ macrophage subset, downregulation of the anti-inflammatory CD206+/CD163+ subset, increase in p38 phosphorylation, and increase in cell-bound and secreted interleukin-1β stimulated by LPS, at least in part through signalling pathways not involving Toll-like receptor 4 and nuclear factor-κB. Thus, the curcumin analogue GG9 attenuated the LPS-induced inflammatory response in human blood-derived macrophages and may therefore represent an attractive chemical template for macrophage pharmacological targeting.openTedesco, Serena; Zusso, Morena; Facci, Laura; Trenti, Annalisa; Boscaro, Carlotta; Belluti, Federica; Fadini, Gian Paolo; Skaper, Stephen D.; Giusti, Pietro; Bolego, Chiara; Cignarella, AndreaTedesco, Serena; Zusso, Morena; Facci, Laura; Trenti, Annalisa; Boscaro, Carlotta; Belluti, Federica; Fadini, Gian Paolo; Skaper, Stephen D.; Giusti, Pietro; Bolego, Chiara; Cignarella, Andre

Fasudil in Combination With Bone Marrow Stromal Cells (BMSCs) Attenuates Alzheimer\u27s Disease-Related Changes Through the Regulation of the Peripheral Immune System.

Alzheimer\u27s disease (AD) is a chronic progressive neurodegenerative disease. Its mechanism is still not clear. Majority of research focused on the central nervous system (CNS) changes, while few studies emphasize on peripheral immune system modulation. Our study aimed to investigate the regulation of the peripheral immune system and its relationship to the severity of the disease after treatment in an AD model of APPswe/PSEN1dE9 transgenic (APP/PS1 Tg) mice. APP/PS1 Tg mice (8 months old) were treated with the ROCK-II inhibitor 1-(5-isoquinolinesulfonyl)-homo-piperazine (Fasudil) (intraperitoneal (i.p.) injections, 25 mg/kg/day), bone marrow stromal cells (BMSCs; caudal vein injections, 1 × 1