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Adult-onset Still’s disease (AOSD) is a multi-systemic inflammatory disorder of unknown etiology. To date, no single diagnostic test is available for AOSD. Herein, we investigated the pathogenic role of microRNAs in AOSD. MicroRNA profiles in plasma from AOSD patients and healthy controls were analyzed by microarray analysis, followed by quantitative reverse transcription PCR validation. The biological functions of microRNAs were evaluated using in vitro cell-based assay. Among the differentially expressed microRNAs, microRNA-134 (miR-134) expression was positively correlated with AOSD activity scores and significantly decreased after effective treatment. An increased miR-134 level is significantly associated with the activation of Toll-like receptor 3 (TLR3). The reporter assay identified IL-18 binding protein (IL-18BP) as the target of miR-134. A negative correlation between miR-134 expression and IL-18BP mRNA levels were detected in peripheral blood cells following TLR3 ligand treatment. Lower plasma IL-18BP levels and higher IL-18 levels were also observed in active AOSD patients who had higher miR-134 expression than inactive patients. Upregulation of circulating miR-134 was associated with elevated IL-18 levels by targeting IL-18BP in AOSD patients and was positively correlated with disease activity, suggesting its involvement in AOSD pathogenesis. MiR-134 may be a novel activity indicator or potential prognostic biomarker in AOSD.

Mixed cryobulinemia (MC) is the most common chronic hepatitis C virus (HCV)-associated extrahepatic manifestation. C-type lectin 18 (CLEC18) is a novel secretory lectin that is abundantly expressed in hepatocytes and peripheral blood cells (PBCs). We investigated the associations between CLEC18 expression during HCV infection and the presence of extrahepatic manifestations. A total of 41 rheumatic patients with HCV infection (including 28 patients with MC syndrome), 45 rheumatic patients without infection, and 14 healthy subjects were enrolled. The CLEC18 levels in PBCs and serum were determined by using flow cytometry and enzyme-linked immunosorbent assay, respectively. Significantly higher CLEC18 levels were observed in patients with HCV infection (P P P P

OBJECTIVE Several studies have shown that rituximab may enhance hepatitis C virus (HCV) activity. MicroRNAs (miRNAs) have been implicated in modulating the host immune response in HCV infection; miRNAs can be packaged into the exosomes and then shuttled by the exosomes to aid biologic functions. However, the role of exosomal miRNAs (exo-miRNAs) in rituximab-related HCV activity enhancement remains unclear. METHODS The association between rituximab and increased HCV activity was examined using an in vitro cell-based assay. Purified exosomes were confirmed using immunoblotting and flow cytometry and quantified using enzyme-linked immunosorbent assay. Exosomal miRNA-155 (exo-miR-155) levels were measured using quantitative reverse transcription-polymerase chain reaction. RESULTS In vitro data showed that B cell-derived miR-155 could inhibit HCV replication in hepatocytes through exosome transmission. Rituximab could both induce B cell depletion and affect intracellular miR-155 production as well as exo-miR-155 transmission and then enhance HCV activity in hepatocytes (P < 0.005). Serum exosome levels were increased in rheumatoid arthritis (RA) patients with HCV infection compared with the levels in RA patients without HCV infection (P < 0.01). The exo-miR-155 levels were significantly increased in RA patients with HCV infection compared with those without infection (P < 0.01). A significantly greater decrement of exo-miR-155 expression was observed after rituximab therapy compared with those observed before therapy (P < 0.01), and hepatitis C viral loads increased simultaneously (P < 0.05). CONCLUSION Circulating exo-miR-155 levels were negatively correlated with hepatitis C viral loads and subsequently associated with rituximab-related HCV activity enhancement in RA patients. Exo-miR-155 may become a potential diagnostic biomarker or therapeutic target.

Establishing an efficient differentiation procedure is prerequisite for the cell transplantation of pluripotent stem cells. Activating fibroblast growth factor (FGF) signals and inhibiting the activin/nodal pathway are both conserved principles to direct the neural induction (NI) of developing embryos and human embryonic stem cells (hESCs). Wnt signal and OCT4 expression are critical for the hESC pluripotency; however, their roles in cell differentiation are largely unclear. We demonstrate that in the presence of FGF2 and activin inhibitor SB431542, applying a small-molecule Wnt agonist, BIO, efficiently and rapidly steers the NI of all our tested hESCs. A human induced pluripotent stem cell (iPSC), which is refractory for efficient neural conversion by FGF2, effectively differentiated to SOX1+ cells after the BIO/SB431542/FGF2 treatment. In addition, BIO promoted cell survival and transiently sustained OCT4 expression at the early NI stage with FGF2 and SB431542. Interestingly, at the late NI stage, the OCT4 level rapidly declined in the treated hESCs and consequently initiated the formation of neural rosettes with forebrain neuron characteristics. This study illustrates the distinct effects of Wnt activation on maintaining pluripotency and committing neural lineages at the early and late NI stages of hESCs and iPSCs, respectively.

Pluripotent human embryonic stem cells (hESCs) can be efficiently directed to become immature neuroepithelial precursor cells (NPCs) and functional mature neural cells, including neurotransmitter-secreting neurons and glial cells. Investigating the susceptibility of these hESCs-derived neural cells to neurotrophic viruses, such as Japanese encephalitis virus (JEV), provides insight into the viral cell tropism in the infected human brain. We demonstrate that hESC-derived NPCs are highly vulnerable to JEV infection at a low multiplicity of infection (MOI). In addition, glial fibrillary acid protein (GFAP)-expressing glial cells are also susceptible to JEV infection. In contrast, only a few mature neurons were infected at MOI 10 or higher on the third day post-infection. In addition, functional neurotransmitter-secreting neurons are also resistant to JEV infection at high MOI. Moreover, we discover that vimentin intermediate filament, reported as a putative neurovirulent JEV receptor, is highly expressed in NPCs and glial cells, but not mature neurons. These results indicate that the expression of vimentin in neural cells correlates to the cell tropism of JEV. Finally, we further demonstrate that membranous vimentin is necessary for the susceptibility of hESC-derived NPCs to JEV infection.

Sialic acids (SAs) linked to galactose (Gal) in α2,3- and α2,6-configurations are the receptors for avian and human influenza viruses, respectively. We demonstrate that chicken tracheal ciliated cells express α2,3-linked SA, while goblet cells mainly express α2,6-linked SA. In addition, the plant lectin MAL-II, but not MAA/MAL-I, is bound to the surface of goblet cells, suggesting that SA2,3-linked oligosaccharides with Galβ1-3GalNAc subterminal residues are specifically present on the goblet cells. Moreover, both α2,3- and α2,6-linked SAs are detected on single tracheal basal cells. At a low multiplicity of infection (MOI) avian influenza virus H6N1 is exclusively detected in the ciliated cells, suggesting that the ciliated cell is the major target cell of the H6N1 virus. At a MOI of 1, ciliated, goblet and basal cells are all permissive to the AIV infection. This result clearly elucidates the receptor distribution for the avian influenza virus among chicken tracheal epithelial cells and illustrates a primary cell model for evaluating the cell tropisms of respiratory viruses in poultry.