Exploration of IRES Elements within the ORF of the Coxsackievirus B3 Genome / 生物医学与环境科学（英文）

Objective@#This study aimed to identify internal ribosome entry sites (IRESs) in the open reading frame (ORF) of the Coxsackievirus B3 (CVB3) genome.@*Methods@#The sequences of P1, P2, or P3 of the CVB3 genome or the truncated sequences from each antithymocyte globulin (ATG) to the end of the P1, P2, or P3 gene were inserted into the pEGFP-N1 vector. After transfection, possible IRES-dependent green fluorescent protein (GFP)-fused proteins were detected by anti-GFP western blotting. The sequences of possible IRESs were inserted into specific Fluc/Rluc bicistronic vectors, in which the potential IRESs were determined according to the Fluc/Rluc activity ratio. Expression of Fluc and Rluc mRNA of the bicistronic vector was detected by RT-qPCR.@*Results@#After transfection of full length or truncated sequences of the P1, P2, or P3 plasmids, six GFP-fused protein bands in P1, six bands in P2 and nine bands in P3 were detected through western blotting. Two IRESs in VP2 (1461-1646 nt) and VP1 (2784-2983 nt) of P1; one IRES in 2C (4119-4564 nt) of P2; and two IRESs in 3C (5634-5834 nt) and 3D (6870-7087 nt) of P3 were identified according to Fluc/Rluc activity ratio. The cryptic promoter was also excluded by RT-qPCR.@*Conclusion@#Five IRESs are present in the CVB3 coding region.

Coxsackievirus B3 Infection Triggers Autophagy through 3 Pathways of Endoplasmic Reticulum Stress / 生物医学与环境科学（英文）

OBJECTIVE@#Autophagy is a highly conserved intracellular degradation pathway. Many picornaviruses induce autophagy to benefit viral replication, but an understanding of how autophagy occurs remains incomplete. In this study, we explored whether coxsackievirus B3 (CVB3) infection induced autophagy through endoplasmic reticulum (ER) stress.@*METHODS@#In CVB3-infected HeLa cells, the specific molecules of ER stress and autophagy were detected using Western blotting, reverse transcription polymerase chain reaction (RT-PCR), and confocal microscopy. Then PKR-like ER protein kinase (PERK) inhibitor, inositol-requiring protein-1 (IRE1) inhibitor, or activating transcription factor-6 (ATF6) inhibitor worked on CVB3-infected cells, their effect on autophagy was assessed by Western blotting for detecting microtubule-associated protein light chain 3 (LC3).@*RESULTS@#CVB3 infection induced ER stress, and ER stress sensors PERK/eIF2α, IRE1/XBP1, and ATF6 were activated. CVB3 infection increased the accumulation of green fluorescent protein (GFP)-LC3 punctuation and induced the conversion from LC3-I to phosphatidylethanolamine-conjugated LC3-1 (LC3-II). CVB3 infection still decreased the expression of mammalian target of rapamycin (mTOR) and p-mTOR. Inhibition of PERK, IRE1, or ATF6 significantly decreased the ratio of LC3-II to LC3-I in CVB3-infected HeLa cells.@*CONCLUSION@#CVB3 infection induced autophagy through ER stress in HeLa cells, and PERK, IRE1, and ATF6a pathways participated in the regulation of autophagy. Our data suggested that ER stress may inhibit mTOR signaling pathway to induce autophagy during CVB3 infection.

Inhibition of virus infection in coxsackievirus-induced myocarditis model by RNA interference / 病毒学报

To evaluate the effects of lentivirus-delivered short hairpin RNA (shRNA) on CVB3 infection in an animal model by RNA interference technique, we constructed a recombinant lentivirus expressing shRNA-3753 against the viral genome region 3753-3771, then transduced Lenti-sh3753 into mice infected with CVB3. We evaluated the antiviral ability of lenti-sh3753 by cytopathic effect (CPE), viral plaque assay and histological analysis of mice hearts. The results showed that Lenti-sh3753 exhibited a significant protective effect on cell viability and reduction of viral titers in supernatant of cell culture by specific inhibition on viral replication. Lenti-sh3753 also prolonged the mice survival and limited the viral production in mice hearts. These data proposed that Lenti-sh3753 can effectively inhibit CVB3 infection in a coxsackievirus-induced myocarditis model, suggesting its potential role in prevention and therapy of viral diseases.

Effect of Itk down regulation on cytokines production in Jurkat cell / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the effect of Itk down regulation on Jurkat cell proliferation and inflammatory cytokines production, and provide useful data for Itk as an attractive target for potential drugs.</p><p><b>METHODS</b>Three shRNAs against different region of Itk were constructed and cotransfected with pEGFP-C1-hItk. The shRNA, which can knock down Itk, was selected and packed into lentivirus. After Jurkat cells were transfected with shRNA lentivirus, the change of Itk protein expression, cell proliferation and cytokines production was observed.</p><p><b>RESULTS</b>Itk mRNA was reduced about 55% in Jurkat cells transfected with Itk-shRNA1, compared with that in control cells shRNAnon (P < 0.05). Knocking down Itk expression had a profound inhibitory effect on Jurkat cell proliferation. In addition, there was a substantial decrease in level of cytokines, such as IL-2, IL-5, IL-10 and IFN-gamma, produced by cell transfected with Itk-shRNA1.</p><p><b>CONCLUSION</b>Knocking down Itk expression can inhibit Jurkat cell proliferation and inflammatory cytokines production.</p>

Research of ITK regulation on mouse spleen lymphocytes proliferation and differentiation / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>By using the RNAi method to inhibit Itk protein expression specificity, to observe lymphocytes proliferation and cytokines production, verify its function as a drug target.</p><p><b>METHODS</b>Designed siRNA aims at Itk sequence according to its sequence and solid structure, then electrotransfected into mouse spleen lymphocytes, We validated the decrease of Itk protein by Western-Blot, and detected the change of the cell proliferation by MTS and the change of inflammatory cytokines by ELISA.</p><p><b>RESULTS</b>Itk protein can be suppressed by Itk-siRNA, there were significantly reduced compared to its control group on cell proliferation as well as cytokine secretion such as IL-2, IL-4, IL-5, IFN-gamma. They all have statistical difference (P < 0.05).</p><p><b>CONCLUSION</b>Itk has an important immunomodulatory effect in mouse spleen lymphocytes proliferation and secretion of inflammatory cytokines.This can supply an experimental basis to regard Itk as drug target for inflammation therapy.</p>

Intracellular clearance of Coxsakievirus B3 infection by short interfering RNA and its mechanism study / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To evaluate the possibility of short interfering RNA (siRNA) inhibiting Coxsackievirus B3 (CVB3) infection in vitro, and discover the mechanism initially.</p><p><b>METHODS</b>We obtained proper effective dosage of siRNA by observing cytopathic effect (CPE). Estimate its antiviral activities and its pathway of siRNA by Western Blot assay and RT-PCR.</p><p><b>RESULTS</b>Results showed that siRNA-3753 can be effectively transfected into HeLa cells, we can achieve a high transfection efficiency up to 98.77% and its effect can last for 48 h stably in cells. 0.6 micromol/L siRNA-3753 got a high inhibiting effect of virus and didn't show any toxicity to cells. So we consider this concentration as the experimental concentration. siRNA-3753 can debase virus reproduction. The antiviral effect is sequence-specific and is not attributable to either interferon or the interferon response effectors protein kinase R (PKR).</p><p><b>CONCLUSION</b>The data confirmed that siRNA can effectively inhibit CVB3 infection in vitro, its antivirus effect was gained from specific debase of virus genome.</p>

Study on inhibition of coxsackievirus B3 infection in HeLa cell by short interfering RNA targeting 2B protein / 病毒学报

To study the inhibitory effect and function characteristics of small interfering RNA (siRNA) on cosxackievirus B3(CVB3) infection by RNA interference technique, siRNA-2B against the viral 2B region was synthesized and transfected into HeLa cell, which was then infected with CVB3. The efficiency of siRNA transfection was examined by FCM, the cell toxicity of siRNA-2B by MTT, and the antiviral ability of siRNA-2B by cytopathic effect (CPE), plaque reduction assay and RT-PCR. The results showed that siRNA-2B could be transfected efficiently into HeLa cell and lasted at least 48h. High concentration of siRNA-2B didn't show any sign of toxicity to cells. siRNA-2B exhibited a significant protective effect on cell viability by specific inhibition of viral replication. It showed a close relationship between the concentrations of siRNA-2B and the antiviral effects. siRNA-2B led to dramatical reduction of viral titers in supernatant of cell culture and weakened the reinfection ability of the virus. These data proposed that siRNA-2B, targeting 2B protein, can effectively inhibit CVB3 infection in HeLa cell and exhibits its transfection efficiency, viral inhibition specificity and adose-dependant manner, suggesting its potential role in prevention and treatement of CVB3 infection.

Treatment of scrapie pathogen 263K with tetracycline partially abolishes protease-resistant activity in vitro and reduces infectivity in vivo / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the possible effect of tetracycline on protease-resistant activity in vitro and infectivity in vivo of a scrapie strain 263K.</p><p><b>METHODS</b>Scrapie pathogens were incubated with tetracycline at different concentrations for various periods of time and protease-resistant PrP signals were evaluated with proteinase K-treatment and Western blots. The preparations treated with tetracycline were intracerebrally inoculated into golden hamsters and typical TSE manifestations were noted. PrPSc in brain tissues of the infected animals was detected by PrP specific Western blot assays.</p><p><b>RESULTS</b>Protease-resistant PrP was significantly reduced in or removed from the preparations treated with tetracycline in a dose-dependant manner. Compared with the control group after incubated for 53.75 +/- 0.50 days, the preparations treated with 5 mmol/L and 20 mmol/L tetracycline prolonged the incubation time of 61.5 +/- 1.73 and 59.5 +/- 0.58 days (P < 0.05).</p><p><b>CONCLUSION</b>Treatment of scrapie pathogen 263K with tetracycline reduces or removes its protease-resistant activity in vitro.</p>

Short interfering RNA-mediated inhibition of coxsakievirus B3 infection in vitro / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To evaluate feasibility of inhibiting coxsackievirus B3 (CVB3) infection at cellular, protein and gene levels by using small interfering RNA (siRNA).</p><p><b>METHODS</b>Antiviral activities of siRNAs were evaluated by observing cytopathic effect (CPE), using plaque reduction Western blotting assays and RT-PCR.</p><p><b>RESULTS</b>Eight siRNAs were synthesized, among them, SiRNA-2, SiRNA-3, SiRNA-6 and SiRNA-7 which were targeted against sequences located in 2B, VP4, 2A and 3C section of CVB3 genome, were designed to have different effect of inhibiting CVB3 infection in vitro. SiRNA-2 showed the best protective effect, 95 percent inhibition of CVB3 cytopathic effect and plaque forming effect was observed at 0.0001 MOI, viral protein synthesis and replication were inhibited. SiRNA-2 showed 30 percent inhibition of virus at 0.1 MOI, 70 percent inhibition at 0.01 MOI, 88 percent inhibition at 0.001 MOI, and 99 percent inhibition at 0.0001 MOI 48 hours after CVB3 infection.</p><p><b>CONCLUSION</b>SiRNA could effectively inhibit CVB3 infection in vitro, siRNA-2, which is targeted against sequence in 2B section of CVB3 genome, seemed to be the best one among those synthesized in this study.</p>