Adaptation to endoplasmic reticulum (ER) stress relies on activation of the unfolded protein response (UPR) and induction of autophagy. Indeed, cells die if ER stress is not countered by the UPR. Here we show in U937 cells that the ER stressors tunicamycin and thapsigargin cause increased expression of c-Jun N-terminal kinase 2 (JNK2), which allows regulation of the UPR, whose silencing or pharmacological inhibition delays BiP (immunoglobulin heavy-chain binding protein) upregulation, and causes earlier and greater expression of CCAAT/enhancer-binding protein-homologous protein (CHOP). Furthermore, we show that pharmacological inhibition or silencing of JNK2 causes accumulation of both p62 and the acidic compartment, caspase 3 activation and apoptosis. Our results reveal that JNK2 prevents accumulation of the acidic compartment in U937 cells undergoing autophagic flux and, by this mechanism, it keeps stressed cells alive. Our findings highlight a potential role for JNK2 in tumor cell survival, senescence and neurodegenerative diseases, in which ER stress, autophagy and lysosome activity are known to interplay.

Type 2 is the type of diabetes with higher prevalence in contemporary time, representing about 90% of the global cases of diabetes. In the course of diabetes, several complications can occur, mostly due to hyperglycemia and increased reactive oxygen species (ROS) production. One of them is represented by an increased susceptibility to microbial infections and by a reduced capacity to clear them. Therefore, knowing the impact of hyperglycemia on immune system functionality is of utmost importance for the management of the disease. In this study, we show that medium containing high glucose reduced the in-vitro differentiation of monocytes into functional DCs and their activation mediated by PAMPs or DAMPs. Most importantly, the same effects were mediated by the hyperglycemic sera derived by type 2 diabetic patients, mimicking a more physiologic condition. DC dysfunction caused by hyperglycemia may be involved in the inefficient control of infections observed in diabetic patients, given the pivotal role of these cells in both the innate and adaptive immune response. Searching for the molecular mechanisms underlying DC dysfunction, we found that canonical Wnt/β-catenin and p38 MAPK pathways were activated in the DCs differentiated either in the presence of high glucose or of hyper-glycemic sera. Interestingly, the activation of these pathways and the DC immune dysfunction were partially counteracted by the anti-oxidant quercetin, a flavonoid already known to exert several beneficial effects in diabetes.

Hepatitis C virus (HCV) infection is a leading cause of liver fibrosis, especially in developing countries. The process is characterized by the excess accumulation of ECM that may lead, over time, to hepatic cirrhosis, liver failure and also to hepatocarcinoma. The direct role of HCV in promoting fibroblasts trans-differentiation into myofibroblasts, the major fibrogenic cells, has not been fully clarified. In this study, we found that HCV derived from HCV-infected patients infected and directly induced the trans-differentiation of human primary fibroblasts into myofibroblasts, promoting fibrogenesis. This effect correlated with the activation of GLI2, one of the targets of Hedgehog signaling pathway previously reported to be involved in myofibroblast generation. Moreover, GLI2 activation by HCV correlated with a reduction of autophagy in fibroblasts, that may further promoted fibrosis. GLI2 inhibition by Gant 61 counteracted the pro-fibrotic effects and autophagy inhibition mediated by HCV, suggesting that targeting HH/GLI2 pathway might represent a promising strategy to reduce the HCV-induced fibrosis.

Ganciclovir therapy was given intravenously to 20 children with cytomegalovirus (CMV)-associated liver disease, of whom 6 were immunocompetent and 14 were immunocompromised (9 had AIDS and 5 had solid tumors). Immunocompetent children had isolated liver disease diagnosed at birth (4 children), or systemic congenital CMV infection including liver disease (2 children). Ganciclovir was used following two regimens: A) 5 mg/kg twice daily for 8 to 86 days (mean 21); B) 7.5 mg/kg twice daily for 14 days followed by 10 mg/kg three times weekly for three months. CMV infection was diagnosed by viral isolation, detection of viral antigens, and/or CMV DNA from blood and urine. All immunocompetent children had negative CMV culture and CMV DNA detection from blood and/or urine after 14 weeks of treatment. However, the three children who were treated with regimen B showed normal ALT levels at the end of the maintenance course, whereas the children who received ganciclovir with regimen A had normal ALT levels only after about 1 year. All children with tumors initiated regimen B, but only three, who had negative CMV detection and markedly decreased ALT levels, received full treatment; of the remaining two children, one recovered after only an initial course, and the other had therapy interrupted because of hepatic failure and died 9 days later. In contrast, the children with AIDS received several ganciclovir courses for different periods at the lower dosage: they generally improved during treatment but did not recover completely, and five children died with active CMV infections. Based on our study, CMV-associated liver disease can be efficiently treated with ganciclovir both in immunocompetent and immunodeficient children. However, a single ganciclovir course including a higher dosage and prolonged therapy appeared to be more effective than several courses with lower dosages.

BackgroundFor an efficient immune response against viral infection, dendritic cells (DCs) must express a coordinate repertoire of receptors that allow their recruitment to the sites of inflammation and subsequently to the secondary lymphoid organs in response to chemokine gradients.Several pathogens are able to subvert the chemokine receptor expression and alter the migration properties of DCs as strategy to escape from the immune control.FindingsHere we report the inhibitory effect of Human Herpesvirus 8 (HHV-8) on the migratory behavior of immature and mature DCs. We found that the virus altered the DC chemokine receptor expression and chemokine induced migration. Moreover HHV-8 was also able to interfere with basal motility of DCs by inducing cytoskeleton modifications.ConclusionBased on our findings, we suggest that HHV-8 is able to subvert the DC migration capacity and this represents an additional mechanism which interferes with their immune-functions.