Japanese encephalitis is an acute zoonotic, mosquito-borne disease caused by Japanese encephalitis virus (JEV). Japanese encephalitis is characterized by extensive inflammation in the central nervous system (CNS) and disruption of the blood-brain barrier (BBB). However, the pathogenic mechanisms contributing to the BBB disruption are not known. Here, using a mouse model of intravenous JEV infection, we show that virus titers increased exponentially in the brain from 2 to 5 days postinfection. This was accompanied by an early, dramatic increase in the level of inflammatory cytokines and chemokines in the brain. Enhancement of BBB permeability, however, was not observed until day 4, suggesting that viral entry and the onset of inflammation in the CNS occurred prior to BBB damage. In vitro studies revealed that direct infection with JEV could not induce changes in the permeability of brain microvascular endothelial cell monolayers. However, brain extracts derived from symptomatic JEV-infected mice, but not from mock-infected mice, induced significant permeability of the endothelial monolayer. Consistent with a role for inflammatory mediators in BBB disruption, the administration of gamma interferon-neutralizing antibody ameliorated the enhancement of BBB permeability in JEV-infected mice. Taken together, our data suggest that JEV enters the CNS, propagates in neurons, and induces the production of inflammatory cytokines and chemokines, which result in the disruption of the BBB. IMPORTANCEJapanese encephalitis (JE) is the leading cause of viral encephalitis in Asia, resulting in 70,000 cases each year, in which approximately 20 to 30% of cases are fatal, and a high proportion of patients survive with serious neurological and psychiatric sequelae. Pathologically, JEV infection causes an acute encephalopathy accompanied by BBB dysfunction; however, the mechanism is not clear. Thus, understanding the mechanisms of BBB disruption in JEV infection is important. Our data demonstrate that JEV gains entry into the CNS prior to BBB disruption. Furthermore, it is not JEV infection per se, but the inflammatory cytokines/ chemokines induced by JEV infection that inhibit the expression of TJ proteins and ultimately result in the enhancement of BBB permeability. Neutralization of gamma interferon (IFN-␥) ameliorated the enhancement of BBB permeability in JEV-infected mice, suggesting that IFN-␥ could be a potential therapeutic target. This study would lead to identification of potential therapeutic avenues for the treatment of JEV infection. J apanese encephalitis (JE) is an acute zoonotic, mosquito-borne infectious disease caused by JE virus (JEV) infection. JEV is a single-stranded, positive-sense RNA virus, belonging to the genus Flavivirus of the family Flaviviridae (1, 2). JEV is a neurotropic virus and infection causes an acute encephalopathy. JE commonly affects children in the South Pacific regions of Asia (3, 4). Of nearly 70,000 cases of JE reported each year, ca. 20 to 30% of cases are fatal, and a high proport...

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CXCL12, a ligand for the chemokine receptor CXCR4, is well known in mediating neural progenitor cell (NPC) migration during neural development. However, the effects of CXCL12 on human NPC proliferation and its associated signaling pathways remain unclear. The transcription factor, FOXO3a, a downstream target of Akt‐1, is critical for cell cycle control and may also play an important role in regulating NPC proliferation. In this study, we found that CXCL12 promotes human NPC proliferation as determined by the proliferation marker Ki67 and BrdU incorporation. This CXCL12‐mediated NPC proliferation was associated with an increase in Akt‐1 and FOXO3a phosphorylation in a time‐ and dose‐dependent manner. The CXCR4 antagonist (T140) or inhibitors for G proteins (Pertussis toxin) and phosphoinositide 3‐kinase (PI3K) (LY294002) abolished CXCL12‐mediated NPC proliferation and phosphorylation of Akt‐1 and FOXO3a. The roles of Akt‐1 and FOXO3a in CXCL12‐mediated NPC proliferation were further investigated by using adenoviral over‐expression in NPCs. Over‐expression of dominant‐negative Akt‐1 or wild‐type FOXO3a in NPC abrogated CXCL12‐mediated proliferation. These data suggest that CXCL12‐mediated NPC proliferation is reliant upon the phosphorylation of Akt‐1 and FOXO3a and gives insight to an essential role of CXCL12 in neurogenesis. Understanding this mechanism may facilitate the development of novel therapeutic targets for NPC proliferation during neurogenesis.

The rapidly progressing of coronavirus disease 2019 (COVID-19) pandemic has become a global concern. This meta-analysis aimed at evaluating the efficacy and safety of current option of therapies for severe acute respiratory syndrome (SARS), Middle Eastern respiratory syndrome (MERS) besides COVID-19, in an attempt to identify promising therapy for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients. We searched PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and WANFANG DATA for randomized controlled trials (RCTs), prospective cohort, and retrospective cohort studies that evaluated therapies (hydroxychloroquine, lopinavir/ ritonavir-based therapy, and ribavirin-based therapy, etc.) for SARS, MERS, and COVID-19. The primary outcomes were mortality, virological eradication and clinical improvement, and secondary outcomes were improvement of symptoms and chest radiography results, incidence of acute respiratory disease syndrome (ARDS), utilization of mechanical ventilation, and adverse events (AEs). Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random-effects models, and the quality of evidence was appraised using GRADEpro. Eighteen articles (5 RCTs, 2 prospective cohort studies, and 11 retrospective cohort studies) involving 4,941 patients were included. Compared with control treatment, anti-coronary virus interventions significantly reduced mortality (RR 0.65, 95% CI 0.44-0.96; I 2 = 81.3%), remarkably ameliorate clinical improvement (RR 1.52, 95% CI 1.05-2.19) and radiographical improvement (RR 1.62, 95% CI 1.11-2.36, I 2 = 11.0 %), without manifesting clear effect on virological eradication, incidence of ARDS, intubation, and AEs. Subgroup analyses demonstrated that the combination of ribavirin and corticosteroids remarkably decreased mortality (RR 0.43, 95% CI 0.27-0.68). The lopinavir/ritonavir-based combination showed superior virological eradication and radiographical improvement with reduced rate of ARDS. Likewise, hydroxychloroquine improved radiographical result. For safety, ribavirin could induce more bradycardia, anemia and transaminitis. Meanwhile, hydroxychloroquine could increase AEs rate especially diarrhea. Overall, the quality of evidence on most outcomes were very low. In conclusion, although we could not draw a clear conclusion for the recommendation of potential therapies for COVID-19 considering the very low quality of evidence and wide heterogeneity of interventions and indications, our results may help clinicians to comprehensively understand the advantages and drawbacks of each anti-coronavirus agents on efficacy and safety profiles. Lopinavir/ritonavir combinations might observe better virological eradication capability than other anti-coronavirus agents. Conversely, ribavirin might cause more safety concerns especially bradycardia. Thus, large RCTs objectively assessing the efficacy of antiviral therapies for SARS-CoV-2 infections should...

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Japanese encephalitis is a neuropathological disorder caused by Japanese encephalitis virus (JEV), which is characterized by severe pathological neuroinflammation and damage to the blood–brain barrier (BBB). Inflammatory cytokines/chemokines can regulate the expression of tight junction (TJ) proteins and are believed to be a leading cause of BBB disruption, but the specific mechanisms remain unclear. IP-10 is the most abundant chemokine produced in the early stage of JEV infection, but its role in BBB disruption is unknown. The administration of IP-10-neutralizing antibody ameliorated the decrease in TJ proteins and restored BBB integrity in JEV-infected mice. In vitro study showed IP-10 and JEV treatment did not directly alter the permeability of the monolayers of endothelial cells. However, IP-10 treatment promoted tumor necrosis factor alpha (TNF-α) production and IP-10-neutralizing antibody significantly reduced the production of TNF-α. Thus, TNF-α could be a downstream cytokine of IP-10, which decreased TJ proteins and damaged BBB integrity. Further study indicated that JEV infection can stimulate upregulation of the IP-10 receptor CXCR3 on astrocytes, resulting in TNF-α production through the JNK-c-Jun signaling pathway. Consequently, TNF-α affected the expression and cellular distribution of TJs in brain microvascular endothelial cells and led to BBB damage during JEV infection. Regarding regulation of the BBB, the IP-10/TNF-α cytokine axis could be considered a potential target for the development of novel therapeutics in BBB-related neurological diseases.

Japanese encephalitis virus (JEV) can invade the central nervous system and consequently induce neuroinflammation, which is characterized by profound neuronal cell damage accompanied by astrogliosis and microgliosis. Albeit microRNAs (miRNAs) have emerged as major regulatory noncoding RNAs with profound effects on inflammatory response, it is unknown how astrocytic miRNAs regulate JEV-induced inflammation. Here, we found the involvement of miR-19b-3p in regulating the JEV-induced inflammatory response in vitro and in vivo. The data demonstrated that miR-19b-3p is upregulated in cultured cells and mouse brain tissues during JEV infection. Overexpression of miR-19b-3p led to increased production of inflammatory cytokines, including tumor necrosis factor alpha, interleukin-6, interleukin-1β, and chemokine (C-C motif) ligand 5, after JEV infection, whereas knockdown of miR-19b-3p had completely opposite effects. Mechanistically, miR-19b-3p modulated the JEV-induced inflammatory response via targeting ring finger protein 11, a negative regulator of nuclear factor kappa B signaling. We also found that inhibition of ring finger protein 11 by miR-19b-3p resulted in accumulation of nuclear factor kappa B in the nucleus, which in turn led to higher production of inflammatory cytokines. In vivo silencing of miR-19b-3p by a specific antagomir reinvigorates the expression level of RNF11, which in turn reduces the production of inflammatory cytokines, abrogates gliosis and neuronal cell death, and eventually improves the survival rate in the mouse model. Collectively, our results demonstrate that miR-19b-3p positively regulates the JEV-induced inflammatory response. Thus, miR-19b-3p targeting may constitute a thought-provoking approach to rein in JEV-induced inflammation.IMPORTANCE Japanese encephalitis virus (JEV) is one of the major causes of acute encephalitis in humans worldwide. The pathological features of JEV-induced encephalitis are inflammatory reactions and neurological diseases resulting from glia activation. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression posttranscriptionally. Accumulating data indicate that miRNAs regulate a variety of cellular processes, including the host inflammatory response under pathological conditions. Recently, a few studies demonstrated the role of miRNAs in a JEV-induced inflammatory response in microglia; however, their role in an astrocyte-derived inflammatory response is largely unknown. The present study reveals that miR-19b-3p targets ring finger protein 11 in glia and promotes inflammatory cytokine production by enhancing nuclear factor kappa B activity in these cells. Moreover, administration of an miR-19b-3p-specific antagomir in JEV-infected mice reduces neuroinflammation and lethality. These findings suggest a new insight into the molecular mechanism of the JEV-induced inflammatory response and provide a possible therapeutic entry point for treating viral encephalitis.