Differential innate immune responses to fowl adenovirus serotype 4 infection in Leghorn male hepatocellular and chicken embryo fibroblast cells.

Fowl adenovirus serotype 4 (FAdV-4) infections result in substantial economic losses in the poultry industry. Recent findings have revealed that FAdV-4 significantly suppresses the host immune response upon infection; however, the specific viral and host factors contributing to this immunomodulatory activity remain poorly characterized. Moreover, diverse cell types exhibit differential immune responses to FAdV-4 infection. To elucidate cell-specific host responses, we performed transcriptomic analysis of FAdV-4 infected leghorn male hepatocellular (LMH) and chicken embryo fibroblast (CEF) cells. Although FAdV-4 replicated more efficiently in LMH cells, it provoked limited interferon-stimulated gene induction. In contrast, FAdV-4 infection triggered robust antiviral responses in CEF cells, including upregulation of cytosolic DNA sensing and interferon-stimulated genes. Knockdown of key cytosolic DNA sensing molecules enhanced FAdV-4 replication in LMH cells while reducing interferon-stimulated gene expression. Our findings reveal cell-specific virus-host interactions that provide insight into FAdV-4 pathogenesis while identifying factors that mediate antiviral immunity against FAdV-4.

The H9N2 avian influenza virus increases APEC adhesion to oviduct epithelia by viral NS1 protein-mediated activation of the TGF-ß pathway.

H9N2 avian influenza is a low-pathogenic avian influenza circulating in poultry and wild birds worldwide and frequently contributes to chicken salpingitis that is caused by avian pathogenic Escherichia coli (APEC), leading to huge economic losses and risks for food safety. Currently, how the H9N2 virus contributes to APEC infection and facilitates salpingitis remains elusive. In this study, in vitro chicken oviduct epithelial cell (COEC) model and in vivo studies were performed to investigate the role of H9N2 viruses on secondary APEC infection, and we identified that H9N2 virus enhances APEC infection both in vitro and in vivo. To understand the mechanisms behind this phenomenon, adhesive molecules on the cell surface facilitating APEC adhesion were checked, and we found that H9N2 virus could upregulate the expression of fibronectin, which promotes APEC adhesion onto COECs. We further investigated how fibronectin expression is regulated by H9N2 virus infection and revealed that transforming growth factor beta (TGF-ß) signaling pathway is activated by the NS1 protein of the virus, thus regulating the expression of adhesive molecules. These new findings revealed the role of H9N2 virus in salpingitis co-infected with APEC and discovered the molecular mechanisms by which the H9N2 virus facilitates APEC infection, offering new insights to the etiology of salpingitis with viral-bacterial co-infections.IMPORTANCEH9N2 avian influenza virus (AIV) widely infects poultry and is sporadically reported in human infections. The infection in birds frequently causes secondary bacterial infections, resulting in severe symptoms like pneumonia and salpingitis. Currently, the mechanism that influenza A virus contributes to secondary bacterial infection remains elusive. Here we discovered that H9N2 virus infection promotes APEC infection and further explored the underlying molecular mechanisms. We found that fibronectin protein on the cell surface is vital for APEC adhesion and also showed that H9N2 viral protein NS1 increased the expression of fibronectin by activating the TGF-ß signaling pathway. Our findings offer new information on how AIV infection promotes APEC secondary infection, providing potential targets for mitigating severe APEC infections induced by H9N2 avian influenza, and also give new insights on the mechanisms on how viruses promote secondary bacterial infections in animal and human diseases.

ß-catenin facilitates fowl adenovirus serotype 4 replication through enhancing virus-induced autophagy.

ß-catenin is a key component of the Wnt/ß-catenin signal transduction cascade which is a highly conserved signaling pathway in eukaryotes. Increasing evidence suggests that the Wnt/ß-catenin signaling pathway is involved in the infection of many viruses. However, its role in fowl adenovirus serotype 4 (FAdV-4) replication remains unclear. In the present study, we showed that FAdV-4 infection increased the expression of ß-catenin and promoted the nuclear translocation of ß-catenin. Overexpression of ß-catenin and LiCl treatment stimulated the accumulation of ß-catenin in the nucleus, and then facilitated FAdV-4 replication. Conversely, repression of ß-catenin by inhibitors and siRNA significantly inhibited FAdV-4 replication. Furthermore, inhibition of autophagy by 3-Methyladenine (3-MA) suppressed the FAdV-4 replication, and repression of ß-catenin inhibited the FAdV-4-triggered autophagy. In conclusion, the nuclear translocation of ß-catenin benefits FAdV-4 replication, and suppression of ß-catenin limits FAdV-4 production by inhibiting FAdV-4-induced autophagy. These findings indicated that ß-catenin is an important regulator of FAdV-4 replication which can serve as a potential target for anti-FAdV-4 agents.

[Anti-inflammation of simvastatin by polarization of murine macrophages from M1 phenotype to M2 phenotype].

OBJECTIVE: To explore the effects of statin on pro-inflammatory macrophage phenotype in a murine M1 macrophage model. METHODS: Macrophages isolated from murine bone barrow were stimulated with interferon-gamma (IFN-γ) and lipopolysaccharide (LPS) to establish a M1 macrophage model. And 1.0, 2.5, 5.0 µmol/L of simvastatin were added to M1 macrophages for a 9-hour culture. Cell surface markers CD16/23 and CD206 were detected by fluorescence activated cell sorter (FACS) and interleukin-10 (IL-10) and IL-12 by ELISA. RESULTS: The CD16/32 expression was 86.39% ± 2.24% and IL-12 secretion (1562 ± 217) pg/ml in IFN-γ and LPS-stimulated macrophages. After a 9-hour incubation with 1.0, 2.5, 5.0 µmol/L simvastatin, the CD206 expression levels were 68.10% ± 2.48%, 75.28% ± 1.66%, 86.32% ± 2.19% and the secretion of IL-10 (500 ± 5), (675 ± 28) and (916 ± 15) pg/ml respectively. By analysis of variance and q test of mean, the difference was statistically significant (all P < 0.01) between the groups of M1 model (9.67% ± 5.48%, (298 ± 11) pg/ml) . And the phenotypic features were similar to those of the groups of M2 model. CONCLUSION: Simvastatin may inhibit inflammation by enhancing the switching of M1 macrophage to M2 macrophage phenotype.

[Reduced circulating endothelial progenitor cells is a risk factor of coronary slow flow].

OBJECTIVE: To explore if reduced number of circulating endothelial progenitor cells (EPCs) is a risk factor for patients with coronary slow flow (CSF). METHODS: Thirty patients with CSF and 30 age and gender matched control subjects with normal coronary angiography were included in the study. Mononuclear cells were isolated from peripheral blood by Ficoll density gradient centrifugation and plated on fibronectin-coated culture dishes. EPCs were characterized as adherent cells double positive for DiI-AcLDL-uptake and lectin-binding by converted fluorescence microscope (×200). RESULTS: Smoking, diabetes mellitus, hypertension and the levels of plasma lipoprotein profile were similar between the two groups (all P > 0.05). The number of EPCs was significantly lower in patients with CSF compared with control subjects (35.7 ± 5.9 vs.53.2 ± 5.9, P < 0.01). TIMI frame counts was correlated with circulating EPCs number (OR = 0.424, 95%CI 0.358 - 0.621, P < 0.01) and not associated with gender, age, smoking, diabetes mellitus, hypertension and the levels of plasma lipoprotein profile. CONCLUSION: Decreased circulating EPCs is an independent risk factor for CSF.

Reduced circulating endothelial progenitor cells in the coronary slow flow phenomenon.

INTRODUCTION: Endothelial progenitor cells (EPCs) are important for maintaining the normal function and structure of endothelial cells. We tested the hypothesis that patients with coronary slow flow (CSF) have reduced circulating EPCs that may contribute to the pathogenesis of the CSF phenomenon. MATERIALS AND METHODS: Twenty patients with angiographically proven normal coronary flow (the control group; mean age=55.6±8.2 years) and 20 patients with angiographically proven CSF in any coronary artery (the patient group; mean age=56.6±9.7 years) were included in the study. The thrombolysis in myocardial infarction (TIMI) frame count technique was used to document the coronary flow rates for all of the patients. Ficoll density gradient centrifugation was used to isolate mononuclear cells from peripheral blood cells. An inverted fluorescence microscope and direct fluorescent antibody staining were used to identify EPCs. RESULTS: The number of EPCs was significantly reduced in the CSF patient group compared with the control group (36.95±6.1 vs. 53.95±6.7 EPCs/×200 field, P<0.01). A multivariate stepwise regression showed a significant negative correlation between the mean TIMI frame counts and the numbers of EPCs (regression coefficient B=-0.65, P<0.01). CONCLUSION: The number of EPCs was reduced and correlated negatively with the TIMI frame count in the CSF patients. Reduced EPCs may be associated with the pathophysiological process of CSF phenomenon.