Anti-CSF2 monoclonal antibody, clone 3C2

Background: Recent fate-mapping studies establish that microglia, the resident mononuclear phagocytes of the CNS, are distinct in origin from the bone marrow-derived myeloid lineage. Interferon regulatory factor 8 (IRF8, also known as interferon consensus sequence binding protein) plays essential roles in development and function of the bone marrow-derived myeloid lineage. However, little is known about its roles in microglia. Methods: The CNS tissues of IRF8-deficient mice were immunohistochemically analyzed. Pure microglia isolated from wild-type and IRF8-deficient mice were studied in vitro by proliferation, immunocytochemical and phagocytosis assays. Microglial response in vivo was compared between wild-type and IRF8-deficient mice in the cuprizon-induced demyelination model. Results: Our analysis of IRF8-deficient mice revealed that, in contrast to compromised development of IRF8-deficient bone marrow myeloid lineage cells, development and colonization of microglia are not obviously affected by loss of IRF8. However, IRF8-deficient microglia demonstrate several defective phenotypes. In vivo, IRF8-deficient microglia have fewer elaborated processes with reduced expression of IBA1/AIF1 compared with wild-type microglia, suggesting a defective phenotype. IRF8-deficient microglia are significantly less proliferative in mixed glial cultures than wild-type microglia. Unlike IRF8-deficient bone marrow myeloid progenitors, exogenous macrophage colony stimulating factor (colony stimulating factor 1) (M-CSF (CSF1)) restores their proliferation in mixed glial cultures. In addition, IRF8-deficient microglia exhibit an exaggerated growth response to exogenous granulocyte-macrophage colony stimulating factor (colony stimulating factor 2) (GM-CSF (CSF2)) in the presence of other glial cells. IRF8-deficient microglia also demonstrate altered cytokine expressions in response to interferon-gamma and lipopolysaccharide in vitro. Moreover, the maximum phagocytic capacity of IRF8-deficient microglia is reduced, although their engulfment of zymosan particles is not overtly impaired. Defective scavenging activity of IRF8-deficient microglia was further confirmed in vivo in the cuprizone-induced demyelination model in mice. Conclusions: This study is the first to demonstrate the essential contribution of IRF8-mediated transcription to a broad range of microglial phenotype. Microglia are distinct from the bone marrow myeloid lineage with respect to their dependence on IRF8-mediated transcription.

Purpose To evaluate the vas deferens and testicles of rats submitted to bilateral inguinotomy and polypropylene (PP) mesh placement. Method Sixty Wistar rats were randomized into three groups: Control (inguinotomy only), mesh placement over the vas deferens (Mesh-DD) or under the spermatic funiculus (Mesh-SF). The following analyses were performed: vas deferens morphometry (lumen area and wall thickness), quantification of collagen fibers, spermatogenesis, apoptosis (cleaved caspase-3 and TUNEL) and cellular proliferation (Ki67). Quantitative gene expression (qPCR) for apoptosis and inflammatory cytokines were evaluated by RT-PCR. Results In the apoptosis pathway, Mesh-DD showed one upregulated gene (Il10) and three downregulated genes (Fadd, Tnfrsf1b and Xiap). In Mesh-SF, 17 genes were downregulated. In the inflammation pathway (Mesh-DD), one gene was upregulated (Il1r1), and one gene was downregulated (Ccl12). In Mesh-SF, three genes were upregulated (Il1r1, Tnfsf13b and Csf1), and two were downregulated (Ccl12 and Csf2). PP mesh placement preserved spermatogenesis and did not alter the vas deferens or the testicle. In the ductus deferens, there was reduced luminal area (30 days), increased wall thickness (90 days), and increased type III collagen and cell proliferation (30 and 90 days) (p < 0.05). In the testicle, cell proliferation was greater in the Mesh-DD (p < 0.05). Conclusions PP mesh, whether or not in direct contact with spermatic funicular structures, induces changes that were not sufficient to cause damage to the evaluated organs.