Objective. Rheumatoid arthritis therapies that are based on inhibition of a single cytokine, e.g., tumor necrosis factor ␣ (TNF␣) or interleukin-6 (IL-6), produce clinically meaningful responses in only about half of the treated patients. This study was undertaken to investigate whether combined inhibition of TNF␣ and IL-17 has additive or synergistic effects in the suppression of mesenchymal cell activation in vitro and inflammation and tissue destruction in arthritis in vivo. Methods. Cultures of human fibroblast-like synoviocytes (FLS

The initial reaction of tetrapyrrole formation in archaea is catalyzed by a NADPH-dependent glutamyltRNA reductase (GluTR). The hemA gene encoding GluTR was cloned from the extremely thermophilic archaeon Methanopyrus kandleri and overexpressed in Escherichia coli. Purified recombinant GluTR is a tetrameric enzyme with a native M r ‫؍‬ 190,000 ؎ 10,000. Using a newly established enzyme assay, a specific activity of 0.75 nmol h ؊1 mg ؊1 at 56°C with E. coli glutamyl-tRNA as substrate was measured. A temperature optimum of 90°C and a pH optimum of 8.1 were determined. Neither heme cofactor, nor flavin, nor metal ions were required for GluTR catalysis. Heavy metal compounds, Zn 2؉ , and heme inhibited the enzyme. GluTR inhibition by the newly synthesized inhibitor glutamycin, whose structure is similar to the 3 end of the glutamyl-tRNA substrate, revealed the importance of an intact chemical bond between glutamate and tRNA Glu for substrate recognition. The absolute requirement for NADPH in the reaction of GluTR was demonstrated using four NADPH analogues. Chemical modification and site-directed mutagenesis studies indicated that a single cysteinyl residue and a single histidinyl residue were important for catalysis. It was concluded that during GluTR catalysis the highly reactive sulfhydryl group of Cys-48 acts as a nucleophile attacking the ␣-carbonyl group of tRNA-bound glutamate with the formation of an enzyme-localized thioester intermediate and the concomitant release of tRNA Glu . In the presence of NADPH, direct hydride transfer to enzyme-bound glutamate, possibly facilitated by His-84, leads to glutamate-1-semialdehyde formation. In the absence of NADPH, a newly discovered esterase activity of GluTR hydrolyzes the highly reactive thioester of tRNA Glu to release glutamate.

By non-covalent association after proteolytic cleavage, the pro-domains modulate the activities of the mature growth factor domains across the transforming growth factor-␤ family. In the case of bone morphogenic protein 9 (BMP9), however, the pro-domains do not inhibit the bioactivity of the growth factor, and the BMP9⅐pro-domain complexes have equivalent biological activities as the BMP9 mature ligand dimers. By using realtime surface plasmon resonance, we could demonstrate that either binding of pro-domain-complexed BMP9 to type I receptor activin receptor-like kinase 1 (ALK1), type II receptors, coreceptor endoglin, or to mature BMP9 domain targeting antibodies leads to immediate and complete displacement of the pro-domains from the complex. Vice versa, pro-domain binding by an anti-pro-domain antibody results in release of the mature BMP9 growth factor. Based on these findings, we adjusted ELISA assays to measure the protein levels of different BMP9 variants. Although mature BMP9 and inactive precursor BMP9 protein were directly detectable by ELISA, BMP9⅐pro-domain complex could only be measured indirectly as dissociated fragments due to displacement of mature growth factor and prodomains after antibody binding. Our studies provide a model in which BMP9 can be readily activated upon getting into contact with its receptors. This increases the understanding of the underlying biology of BMP9 activation and also provides guidance for ELISA development for the detection of circulating BMP9 variants.Bone morphogenic protein 9 (BMP9 2 ; also known as growth and differentiation factor 2 (GDF2)), is a member of the transforming growth factor ␤ (TGF␤) superfamily. BMP9 is constitutively expressed in liver and secreted into the circulation at active concentrations (1). Circulating BMP9 is a potent biological effector signaling through type I receptor activin-receptorlike kinase 1 (ALK1) in endothelial cells, thereby maintaining vascular homeostasis (2, 3). BMP9 and ALK1 are required for properly organized blood and lymphatic vascular development (4 -6). Human mutations in ALK1 lead to a genetic vascular disorder known as hereditary hemorrhagic telangiectasia (7). Recently, mutations in BMP9 have been identified in individuals with a vascular disorder phenotypically overlapping with hereditary hemorrhagic telangiectasia (8). BMP9 was also discovered to function as a neurotropic factor, potently inducing and maintaining the cholinergic phenotype in the central nervous system (9), and is also the most potent BMP for inducing osteogenic, and to a lesser extent adipogenic and chondrogenic differentiation (10, 11). Osteogenic signaling requires both ALK1 and the low affinity type I receptor ALK2 (12). Type II receptors activin receptor IIA and IIB (ActRIIA and ActRIIB) and BMP receptor II (BMPRII) have also been implicated in ALK1/BMP9 signaling (13). Moreover, endoglin (ENG) has been identified as a co-receptor that can increase BMP9/ALK1 signaling (3,14). This is reflected in a model where ENG and ALK1 act together to bind...

Recombinant interferon-alpha (IFN-α) is an approved therapy for chronic hepatitis B (CHB), but the molecular basis of treatment response remains to be determined. The woodchuck model of chronic hepatitis B virus (HBV) infection displays many characteristics of human disease and has been extensively used to evaluate antiviral therapeutics. In this study, woodchucks with chronic woodchuck hepatitis virus (WHV) infection were treated with recombinant woodchuck IFN-α (wIFN-α) or placebo (n = 12/group) for 15 weeks. Treatment with wIFN-α strongly reduced viral markers in the serum and liver in a subset of animals, with viral rebound typically being observed following cessation of treatment. To define the intrahepatic cellular and molecular characteristics of the antiviral response to wIFN-α, we characterized the transcriptional profiles of liver biopsies taken from animals (n = 8–12/group) at various times during the study. Unexpectedly, this revealed that the antiviral response to treatment did not correlate with intrahepatic induction of the majority of IFN-stimulated genes (ISGs) by wIFN-α. Instead, treatment response was associated with the induction of an NK/T cell signature in the liver, as well as an intrahepatic IFN-γ transcriptional response and elevation of liver injury biomarkers. Collectively, these data suggest that NK/T cell cytolytic and non-cytolytic mechanisms mediate the antiviral response to wIFN-α treatment. In summary, by studying recombinant IFN-α in a fully immunocompetent animal model of CHB, we determined that the immunomodulatory effects, but not the direct antiviral activity, of this pleiotropic cytokine are most closely correlated with treatment response. This has important implications for the rational design of new therapeutics for the treatment of CHB.

Candida albicans is an inhabitant of mucosal surfaces in healthy individuals but also the most common cause of fungal nosocomial blood stream infections, associated with high morbidity and mortality. As such life-threatening infections often disseminate from superficial mucosal infections we aimed to study the use of probiotic Lactobacillus rhamnosus GG (LGG) in prevention of mucosal C. albicans infections. Here, we demonstrate that LGG protects oral epithelial tissue from damage caused by C. albicans in our in vitro model of oral candidiasis. Furthermore, we provide insights into the mechanisms behind this protection and dissect direct and indirect effects of LGG on C. albicans pathogenicity. C. albicans viability was not affected by LGG. Instead, transcriptional profiling using RNA-Seq indicated dramatic metabolic reprogramming of C. albicans. Additionally, LGG had a significant impact on major virulence attributes, including adhesion, invasion, and hyphal extension, whose reduction, consequently, prevented epithelial damage. This was accompanied by glucose depletion and repression of ergosterol synthesis, caused by LGG, but also due to blocked adhesion sites. Therefore, LGG protects oral epithelia against C. albicans infection by preventing fungal adhesion, invasion and damage, driven, at least in parts, by metabolic reprogramming due to nutrient limitation caused by LGG.

These data further emphasize the importance of CRTH2 in eosinophil function and show that Cay10471 is a highly potent and selective antagonist of PGD(2)-induced eosinophil responses. Cay10471 might hence be a useful compound for the treatment of allergic diseases.

No abstract

Pseudozyma aphidis is an efficient producer of mannosylerythritol lipids exceeding concentrations of >100 g/liter from renewable feed stocks. Additionally, a biosurfactant cellobiose lipid is also secreted during nitrogen limitation. Here, we describe the sequencing of P. aphidis to unravel the genomic basis of biosurfactant metabolism in P. aphidis.