RESUMO
Flaviviruses target their replication on membranous structures derived from the ER, where both viral and host proteins play crucial structural and functional roles. Here, we have characterized the involvement of the ER-associated degradation (ERAD) pathway core E3 ligase complex (SEL1L-HRD1) regulator proteins in the replication of Japanese encephalitis virus (JEV). Through high-resolution immunofluorescence imaging of JEV-infected HeLa cells, we observe that the virus replication complexes marked by NS1 strongly colocalize with the ERAD adapter SEL1L, lectin OS9, ER-membrane shuttle factor HERPUD1, E3 ubiquitin ligase HRD1 and rhomboid superfamily member DERLIN1. NS5 positive structures also show strong overlap with SEL1L. While these effectors show significant transcriptional upregulation, their protein levels remain largely stable in infected cells. siRNA mediated depletion of OS9, SEL1L, HERPUD1 and HRD1 significantly inhibit viral RNA replication and titres, with SEL1L depletion showing the maximum attenuation of replication. By performing protein translation arrest experiments, we show that SEL1L, and OS9 are stabilised upon JEV infection. Overall results from this study suggest that these ERAD effector proteins are crucial host-factors for JEV replication.
Assuntos
Vírus da Encefalite Japonesa (Espécie) , Degradação Associada com o Retículo Endoplasmático , Proteínas de Membrana , Ubiquitina-Proteína Ligases , Replicação Viral , Humanos , Vírus da Encefalite Japonesa (Espécie)/fisiologia , Vírus da Encefalite Japonesa (Espécie)/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Células HeLa , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Interações Hospedeiro-Patógeno , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/virologia , Proteínas/metabolismo , Proteínas/genética , Antígenos de DiferenciaçãoRESUMO
RNA virus infections have been a leading cause of pandemics. Aided by global warming and increased connectivity, their threat is likely to increase over time. The flaviviruses are one such RNA virus family, and its prototypes such as the Japanese encephalitis virus (JEV), Dengue virus, Zika virus, West Nile virus, etc., pose a significant health burden on several endemic countries. All viruses start off their life cycle with an infected cell, wherein a series of events are set in motion as the virus and host battle for autonomy. With their remarkable capacity to hijack cellular systems and, subvert/escape defence pathways, viruses are able to establish infection and disseminate in the body, causing disease. Using this strategy, JEV replicates and spreads through several cell types such as epithelial cells, fibroblasts, monocytes and macrophages, and ultimately breaches the blood-brain barrier to infect neurons and microglia. The neurotropic nature of JEV, its high burden on the paediatric population, and its lack of any specific antivirals/treatment strategies emphasise the need for biomedical research-driven solutions. Here, we highlight the latest research developments on Japanese encephalitis virus-infected cells and discuss how these can aid in the development of future therapies.
Assuntos
Vírus da Encefalite Japonesa (Espécie) , Flavivirus , Vírus do Nilo Ocidental , Infecção por Zika virus , Zika virus , Criança , Humanos , Vírus da Encefalite Japonesa (Espécie)/genética , Vírus da Encefalite Japonesa (Espécie)/metabolismo , Vírus do Nilo Ocidental/fisiologia , Barreira HematoencefálicaRESUMO
Japanese encephalitis virus (JEV) pathogenesis is driven by a combination of neuronal death and neuroinflammation. We tested 42 FDA-approved drugs that were shown to induce autophagy for antiviral effects. Four drugs were tested in the JE mouse model based on in vitro protective effects on neuronal cell death, inhibition of viral replication, and anti-inflammatory effects. The antipsychotic phenothiazines Methotrimeprazine (MTP) & Trifluoperazine showed a significant survival benefit with reduced virus titers in the brain, prevention of BBB breach, and inhibition of neuroinflammation. Both drugs were potent mTOR-independent autophagy flux inducers. MTP inhibited SERCA channel functioning, and induced an adaptive ER stress response in diverse cell types. Pharmacological rescue of ER stress blocked autophagy and antiviral effect. MTP did not alter translation of viral RNA, but exerted autophagy-dependent antiviral effect by inhibiting JEV replication complexes. Drug-induced autophagy resulted in reduced NLRP3 protein levels, and attenuation of inflammatory cytokine/chemokine release from infected microglial cells. Our study suggests that MTP exerts a combined antiviral and anti-inflammatory effect in JEV infection, and has therapeutic potential for JE treatment.
Assuntos
Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa , Animais , Camundongos , Vírus da Encefalite Japonesa (Espécie)/fisiologia , Metotrimeprazina/farmacologia , Metotrimeprazina/uso terapêutico , Doenças Neuroinflamatórias , Encefalite Japonesa/tratamento farmacológico , Encefalite Japonesa/patologia , Antivirais/farmacologia , Antivirais/uso terapêutico , Autofagia , Anti-Inflamatórios/uso terapêuticoRESUMO
BACKGROUND: Endogenous endophthalmitis refers to the intraocular infection resulting via haematogenous spread from the distant foci. Dengue is an important health problem in India with varied ophthalmic manifestations either due to viremia, immunologic phenomenon, or haemorrhagic tendency. CASE: We report an unusual presentation of endogenous endophthalmitis as fulminant orbital cellulitis in a young adult patient having a history of dengue fever. OBSERVATIONS: Young male having history of dengue fever presented with complaints of sudden pain, swelling, redness, and loss of vision in the left eye. His clinical features and radiographic examination were suggestive of orbital cellulitis with pan-ophthalmitis, which rapidly progressed to endophthalmitis. CONCLUSION: This case highlights the role of orbital vessels as a possible route for occurrence of endophthalmitis in a case of orbital cellulitis.