The outcomes of corneal sight rehabilitating surgery in Stevens-Johnson syndrome: case series.

PURPOSE: To summarize the outcomes of corneal sight rehabilitating surgery in Stevens-Johnson syndrome (SJS). METHODS: This is a retrospective analysis of a consecutive case series. Twenty-four eyes of 18 SJS patients were included in this study. The ocular parameters, surgical procedures, postoperative complications, and additional treatments of the cases were reviewed. RESULTS: A total of 29 corneal sight rehabilitating surgeries, which consists of 9 keratoplasties, 8 Keratolimbal allograft (KLAL) and 12 combined surgeries (keratoplasty and KLAL simultaneously) were performed on the 24 eyes. All patients were treated with glucocorticoid eyedrops and tacrolimus eyedrops for anti-rejection treatment without combining systemic immunosuppression, except two patients who were prescribed prednisone tablets for the management of systemic conditions. The mean follow-up period was 50.6 ± 28.1 months. The optimal visual acuity (VA) (0.74 ± 0.60 logarithm of the minimum angle of resolution [logMAR]) and endpoint VA (1.06 ± 0.82 logMAR) were both significantly better than the preoperative VA (1.96 ± 0.43 logMAR) (95% CI, p = 0.000). 57.1% patients (8/14) were no longer in the low vision spectrum, and 88.9% patients (8/9) were no longer blind. The mean epithelialization time was 7.1 ± 7.6 weeks. The success rate was 86.7%. Additional treatments for improving epithelialization included administration of serum eyedrops (n = 10), contact lens (n = 15), amniotic membrane transplantation (n = 6), and tarsorrhaphy (n = 8). Complications included delayed epithelialization (n = 4, over 12 weeks), glaucoma (n = 11), and severe allograft opacity (n = 4). Only one graft rejection was observed. CONCLUSIONS: Keratoplasty and KLAL can remarkably enhance VA and improve low vision or even eliminate blindness for ocular complications of SJS. The outcome of the surgeries was correlated with the preoperative ocular situation and choice of operative methods.

Associations of Digital Ulcers in Patients with Systemic Sclerosis: An 8-Year Retrospective Study.

INTRODUCTION: This study aimed to investigate the associations of digital ulcers (DUs) in patients with systemic sclerosis (SSc). METHODS: This retrospective study investigated the demographic characteristics, specific autoantibodies, organ involvement, and laboratory tests in patients with SSc from our hospital. RESULTS: This study enrolled 144 patients with SSc. The DU+ group consisted of 15 (10.4%) patients. Patients with SSc having DUs have longer disease duration, higher fibrinogen, higher fibrin degradation product, and lower cholesterol. None of the patients used cholesterol-lowering drugs before onset of DUs. The study also demonstrated a higher prevalence of anti-dsDNA and anti-histone antibodies in patients with SSc with DUs. Anti-dsDNA antibody is a specific antibody for SLE with a specificity of 96-99%. A total of 86.1% (124/144) of patients suffered from diffuse cutaneous SSc, and 28.5% (41/144) of patients suffered from overlap syndrome. CONCLUSION: Our study indicated that patients with SSc with fibrinogen of >2.895 g/L (p = 0.043) and cholesterol of <3.340 mmol/L (p = 0.036), which is equal to 129.258 mg/dL, are at high risk of developing DUs.

Label-Free Detection of CA19-9 Using a BSA/Graphene-Based Antifouling Electrochemical Immunosensor.

Evaluating the levels of the biomarker carbohydrate antigen 19-9 (CA19-9) is crucial in early cancer diagnosis and prognosis assessment. In this study, an antifouling electrochemical immunosensor was developed for the label-free detection of CA19-9, in which bovine serum albumin (BSA) and graphene were cross-linked with the aid of glutaraldehyde to form a 3D conductive porous network on the surface of an electrode. The electrochemical immunosensor was characterized through the use of transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscope (AFM), UV spectroscopy, and electrochemical methods. The level of CA19-9 was determined through the use of label-free electrochemical impedance spectroscopy (EIS) measurements. The electron transfer at the interface of the electrode was well preserved in human serum samples, demonstrating that this electrochemical immunosensor has excellent antifouling performance. CA19-9 could be detected in a wide range from 13.5 U/mL to 1000 U/mL, with a detection limit of 13.5 U/mL in human serum samples. This immunosensor also exhibited good selectivity and stability. The detection results of this immunosensor were further validated and compared using an enzyme-linked immunosorbent assay (ELISA). All the results confirmed that this immunosensor has a good sensing performance in terms of CA19-9, suggesting its promising application prospects in clinical applications.

The Innovative Biomaterials and Technologies for Developing Corneal Endothelium Tissue Engineering Scaffolds: A Review and Prospect.

Corneal transplantation is the only treatment for corneal endothelial blindness. However, there is an urgent need to find substitutes for corneal endothelium grafts due to the global shortage of donor corneas. An emerging research field focuses on the construction of scaffold-based corneal endothelium tissue engineering (CETE). Long-term success in CETE transplantation may be achieved by selecting the appropriate biomaterials as scaffolds of corneal endothelial cells and adding bioactive materials to promote cell activity. This article reviews the research progress of CETE biomaterials in the past 20 years, describes the key characteristics required for corneal endothelial scaffolds, and summarizes the types of materials that have been reported. Based on these, we list feasible improvement strategies for biomaterials innovation. In addition, we describe the improved techniques for the scaffolds' surface topography and drug delivery system. Some promising technologies for constructing CETE are proposed. However, some questions have not been answered yet, and clinical trials and industrialization should be carried out with caution.

Surface Functionalized Magnetic Nanoparticles as a Selective Sorbent for Affinity Fishing of PPAR-γ Ligands from Choerospondias axillaris.

Coronary heart disease (CHD), which has developed into one of the major diseases, was reported to be treated by the target of peroxisome proliferators-activate receptor γ (PPAR-γ). As a natural medicine long used in the treatment of CHD, there are few studies on how to screen the target active compounds with high specific activity from Choerospondias axillaris. To advance the pace of research on target-specific active compounds in natural medicines, we have combined magnetic ligand fishing and functionalized nano-microspheres to investigate the active ingredients of PPAR-γ targets in Choerospondias axillaris. The PPAR-γ functionalized magnetic nano-microspheres have been successfully synthesized and characterized by vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The specificity, reusability, and reproducibility of the nano-microspheres were investigated with the help of the specific binding of rosiglitazone to PPAR-γ. In addition, the incubation temperature and the pH of the buffer solution in the magnetic ligand fishing were optimized to improve the specific adsorption efficiency of the analytes. Finally, with the aid of ultraperformance liquid chromatography plus Q-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS/MS), the 16 active ligands including 9 organic acids, 5 flavonoids, and 2 phenols were found in the ethanolic extracts of Choerospondias axillaris. Therefore, the study can provide a successful precedent for realizing the designated extraction and rapid isolation of target-specific active ingredient groups in the complex mixtures.

Anti-Inflammatory Effect of Ginsenoside Rg1 on LPS-Induced Septic Encephalopathy and Associated Mechanism.

BACKGROUND: Sepsis frequently occurs in patients after infection and is highly associated with death. Septic encephalopathy is characterized by dysfunction of the central nervous system, of which the root cause is a systemic inflammatory response. Sepsis-associated encephalopathy is a severe disease that frequently occurs in children, resulting in high morbidity and mortality. OBJECTIVES: In the present study, we aimed to investigate the neuroprotective mechanism of ginsenoside Rg1 in response to septic encephalopathy. METHODS: Effects of ginsenoside Rg1 on septic encephalopathy were determined by cell viability, cytotoxicity, ROS responses, apoptosis assays, and histological examination of the brain. Inflammatory activities were evaluated by expression levels of IL-1ß, IL-6, IL-10, TNF-α, and MCP-1 using qPCR and ELISA. Activities of signaling pathways in inflammation were estimated by the production of p-Erk1/2/Erk1/2, p-JNK/JNK, p-p38/p38, p-p65/p65, and p-IkBα/IkBα using western blot. RESULTS: LPS simulation resulted in a significant increase in cytotoxicity, ROS responses, and apoptosis and a significant decrease in cell viability in CTX TNA2 cells, as well as brain damage in rats. Moreover, the production of IL-1ß, IL-6, IL-10, TNF-α, and MCP-1 was reported to be significantly stimulated in CTX TNA2 cells and the brain, confirming the establishment of in vitro and in vivo models of septic encephalopathy. The damage and inflammatory responses induced by LPS were significantly decreased by treatment with Rg1. Western blot analyses indicated that Rg1 significantly decreased the production of p-Erk1/2/Erk1/2, p-JNK/JNK, p-p38/p38, p-p65/p65, and p- IkBα/IkBα in LPS-induced CTX TNA2 cells and brain. CONCLUSION: These findings suggested that Rg1 inhibited the activation of NF-κB and MAPK signaling pathways, which activate the production of proinflammatory cytokines and chemokines. The findings of this study suggested that ginsenoside Rg1 is a candidate treatment for septic encephalopathy.

Microwave-Assisted Extraction Coupled with Mass Spectrometry for Determining Five Volatile Compounds from Soy Sauces.

As a popular fermented condiment in oriental countries, soy sauce plays a more and more important role in modern food culture due to its unique smell and delicious taste. With the help of microwave extraction and gas chromatography-tandem mass spectrometry, the sample preparation method is aimed to determine the content of cyclohexane, benzene, toluene, chlorobenzene, and styrene in soy sauce. The method was validated by examining the linearity, accuracy, specificity, precision, the limit of detection, and quantitation. Meanwhile, three key factors have an impact on the efficiency and accuracy of the method including extracting solvent, temperature, and time which were optimized. The result shows that the recoveries of spiked analytes ranged from 80.86% to 105.71%, the relative standard deviation of intraday and interday precision was no more than 12.1% and 12.5%, and the limit of detection and quantitation were 0.25-1.00 ng/mL and 0.50-2.00 ng/mL, respectively. The results also indicated that the proposed method was a simple, reliable, and sensitive approach for the determination trace amount of five harmful volatile organic compounds from soy sauce.

Magnetic Ligand Fishing Using Immobilized Cyclooxygenase-2 for Identification and Screening of Anticoronary Heart Disease Ligands From Choerospondias axillaris.

Inhibition of cyclooxygenase-2 (COX-2) activity is an effective way for treatment of coronary heart disease. And as an important source of COX-2 inhibitors, bioactive compounds of Choerospondias axillaris and pharmacological mechanisms remained lacking in prospective researches. Therefore, for the purpose of accelerating the discovery of natural products targeting designed inhibitors, the COX-2 microreactor composed of functionalized microspheres and magnetic ligand fishing was developed and applied in Choerospondias axillaris, and the physicochemical properties of the COX-2 functionalized microspheres were characterized using Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Furthermore, the bioactive compounds singled out from ethanol decoction without prepurification were dissociated and identified by ultraperformance liquid chromatography plus Q-Exactive Orbitrap tandem mass spectrometry (UPLC-Q-Exactive Orbitrap-MS/MS). Consequently, 21 bioactive compounds consisting of 6 organic acids, 8 flavonoids, and 7 others were separated and characterized from Choerospondias axillaris, which were reported to participate in the COX-2 inhibitory pathway to varying degrees. Therefore, this method could provide a prospective solution for the extraction and identification of active pharmaceutical ingredients and the rapid screening of some enzyme inhibitors in the complex mixtures.

Methyl Esterification Combined with Gas Chromatography-Mass Spectrometry (GC-MS) for Determining the Contents of Lubricant to Evaluate the Compatibility of Chlorinated Butyl Rubber Stoppers with Liposome Injections.

A simple, sensitive, and exact methyl esterification in combination with gas chromatography-mass spectrometry (GC-MS) method was developed to determine the contents of palmitic acid and stearic acid in the chlorinated butyl rubber stoppers and liposome injections in order to evaluate the compatibility of pharmaceutical packaging materials. In this experiment, palmitic acid and stearic acid were detected in the form of methyl hexadecanoate and methyl stearate in chlorinated butyl rubber stoppers and liposome injections. The results showed good linearities in the range of 0.50-10.00 µg·mL-1 for methyl hexadecanoate and 1.00-20.00 µg·mL-1 for methyl stearate, with the limits of detection (LOD) 11.94 ng·mL-1 and 11.90 ng·mL-1, respectively. The recoveries that ranged from 95.25% to 100.29% were satisfied, and the relative standard deviation (RSD) was no more than 7.16%. The developed method was successfully applied to evaluate the compatibility of chlorinated butyl rubber stoppers with liposome injections and the safety assessment.

Mutations in the HRB linker of human parainfluenza virus type 3 fusion protein reveal its importance for fusion activity.

Human parainfluenza virus type 3 (HPIV3) fuses the viral envelope with the host cell membrane through the concerted action of the fusion (F) protein and the hemagglutinin-neuraminidase (HN). Upon HN binding to sialic acid (SA), the F protein in a metastable prefusion form is activated to undergo a series of structural rearrangements into a stable postfusion form to actuate the fusion between membranes. Various domains of F protein of some other paramyxoviruses, including HPIV3, have been reported to be differently functional. However, it is not yet clear what roles HRB linker plays. To clarify the roles that HRB linker might play in the F-mediated membrane fusion process, here we examined the effects of mutations introduced into the HRB linker of HPIV3 F protein. Six Single amino acid mutants, three chimeric mutants, and one deletion mutant were obtained and analyzed for membrane fusion activity and cell surface expression. The results showed that the membrane fusion activity of mutants changed to varying degrees in comparison with wild-type (wt) F, and some mutants even forfeited fusogenicity absolutely. It is indicated that the HRB linker domain plays an important role in the F-mediated membrane fusion process.

The DI-DII linker of human parainfluenza virus type 3 fusion protein is critical for the virus.

Human parainfluenza virus type 3 (HPIV3) causes the majority of childhood viral pneumonia around the world. Fusing the viral and target cell membranes is crucial for its entry into target cells, and the fusion process requires the concerted actions of two viral glycoproteins: hemagglutinin-neuraminidase (HN) and fusion (F) protein. After binding to the cell surface receptor, sialic acids, HN triggers F to undergo large conformational rearrangements to execute the fusion process. Although it has been reported that several domains of F had important impacts on regulating the membrane fusion activity, what role the DI-DII linker (residues 369-374, namely L1 linker) of the HPIV3 F protein plays in the fusion process still remains confused. We have obtained three chimeric mutant proteins (Ch-NDV-L1, Ch-MV-L1, Ch-HPIV1-L1) containing the full length of HPIV3 F protein but their corresponding DI-DII linker derived from the F protein of Newcastle disease virus (NDV), Measles virus (MV), and Human parainfluenza virus type 1 (HPIV1), respectively. One deletion mutant protein (De-L1), whose DI-DII linker was deleted, has been established simultaneously. Then vaccinia virus-T7 RNA polymerase transient expression system and standard plasmid system were utilized to express the mutant F proteins in BHK-21 cells. These four mutants were determined for membrane fusogenic activity, cell surface expression level, and total mutant F protein expression. All of them resulted in a significant reduction in fusogenic activity in all steps of cell-cell membrane fusion process. There was no significant difference in cell surface protein expression level for the mutants compared with wild-type F. The mutant proteins with inability in fusogenic activity were all at the form of precursor protein, F0, which were not hydrolyzed by intracellular protease furin. The results above suggest that the involvement of the DI-DII linker region is necessary for the complete fusion of the membranes.

Role of the head-stalk linker region (aa115-122) of Newcastle disease virus haemagglutinin-neuraminidase in regulating fusion triggering.

To gain insights into the role of the head-stalk linker region in the fusion triggering, we constructed mutants by deleting or substituting the linker region (115-NGAANNSG-122) of Newcastle disease virus (NDV) haemagglutinin-neuraminidase (HN) with the corresponding sequences of other paramyxoviruses. The results showed that these HN mutants exhibited different levels of fusion-triggering activity, but most of them maintained comparable levels with wide-type HN in both receptor recognition and neuraminidase activity. We tried to figure out reasons for fusion alteration through assessing the expression and the oligomeric state of HN mutants. Moreover, four mutants with significant fusion changes were introduced into the headless HN stem (HN1-123) to intensively investigate the role of the linker region in fusion triggering. Consequently, the stability of HN oligomers and the structural integrity of the 4 helical-bundle of stalk have complicated influences on the alteration of fusion-triggering activities for different mutants. These data suggested that the head-stalk linker could regulate the fusion triggering at both full-length and headless HN levels.

Roles of the highly conserved amino acids in the second receptor binding site of the Newcastle disease virus HN protein.

BACKGROUND: The paramyxovirus haemagglutinin-neuraminidase (HN) is a multifunctional protein that is responsible for attachment to receptors, removal of receptors from infected cells to prevent viral self-aggregation (neuraminidase, NA) and fusion promotion. It is commonly accepted that there are two receptor binding sites in the globular head of HN, and the second receptor binding site is only involved in the function of receptor binding and fusion promotion. METHODS: 10 conserved residues in the second receptor binding site of Newcastle disease virus (NDV) HN were chosen and substituted to alanine (A). The desired mutants were examined to detect the functional change in hemadsorption (HAD) ability, NA activity and fusion promotion ability. RESULTS: The HAD and fusion promotion ability of mutants C172A, R174A, C196A, D198A, Y526A and E547A were abolished. Compared with wild-type (wt) HN, the HAD of mutants T167A, S202A and R516A decreased to 55.81, 44.53, 69.02%, respectively, and the fusion promotion ability of these three mutants decreased to 54.74, 49.46, 65.26%, respectively; however, mutant G171A still maintained fusion promotion ability comparable with wt HN but had impaired HAD ability. All the site-directed mutations altered the NA activity of NDV HN without affecting protein cell surface expression. CONCLUSIONS: The data suggest that mutants C172A, R174A, C196A, D198A, Y526A and E547A do not allow the conformational change that is required for fusion promotion ability and HAD activity, while the other mutants only affect the conformational change to a limited extent, except mutant G171A with intact fusion promotion ability. Overall, the conserved amino acids in the second receptor binding site, especially residues C172, R174, C196, D198, Y526 and E547, are crucial to normal NDV HN protein function.

Genetic characterization and phylogenetic analysis of Newcastle disease virus from China.

The avian infectious disease, Newcastle disease (ND), caused by Newcastle disease virus (NDV) can cause severe economic losses to poultry whether vaccinated or not in many countries. In this study, a strain of NDV isolated from an outbreak in China was subjected to biological, phylogenetic and genetic characterization. The results showed that the mean death time (MDT) was 52.4 h and the intracerebral pathogenicity indices (ICPI) value was 1.95. In addition, amino acid sequencing result showed that it had a sequence 112R-R-Q-R-R↓F117 at fusion protein cleaving site (FPCS) indicating a velogenic strain. And its genome length is 15,192 nucleotide (nt) with the conserved complementary 3' leader and 5' trailer regions encoding six genes, 3'-NP-P-M-F-HN-L-5'. Based on phylogenetic analyses for hyper-variable region and complete genome of F gene, the strain studied here can be clustered into genotype IX, Class II, which has little evolution distance with strains of genotype III, being considered as a transitional strain in the evolution history of NDV. The rescue of infectious cDNA is proceeded in 9-day-old embryonated SPF chicken eggs. Despite the death of the first generation, the allantoic fluid harvested from the first generation lost its pathogenicity after passage. And we found the phenomenon happened due to the antibody appearing in the allantoic fluid. These findings offer our understanding of circulating strains of NDV in China and lay scientific foundations for making more efficient vaccines for Newcastle disease.

Mutations in the DI-DII linker of the NDV fusion protein conferred hemagglutinin-neuraminidase-independent cell fusion promotion.

Newcastle disease (ND), which is caused by Newcastle disease virus (NDV), is a highly contagious disease in chickens and is a great threat to the poultry industry. Fusion of the viral and target cell membranes is a prerequisite for NDV's entry into host cells. This process is directly mediated by the fusion (F) protein. Although several domains of F are known to regulate membrane fusion activity, the roles of the DI-DII linker (residues 376-381) of the NDV F protein in membrane fusion still remain unclear. To investigate the roles of this linker in NDV F-induced cell-cell fusion, mutations were engineered into this linker by site-directed mutagenesis. These mutants were analysed with respect to cell surface expression and membrane fusion activity. Each of the mutated F proteins in this linker was expressed at the cell surface at a similar level to wild-type (WT) F. However, most of them resulted in significant alterations in fusion activity. In particular, the mutants G377S, A378D, L379A and T380P were able to independently mediate cell fusion in the absence of HN protein in BHK-21 cells. Taken together, the results indicated that the DI-DII linker region has an important effect on the fusion activity of NDV F and mutants in this region could alter the requirement for HN for the promotion of membrane fusion.

Conserved amino acids around the DIII-DI linker region of the Newcastle disease virus fusion protein are critical for protein folding and fusion activity.

Newcastle disease virus (NDV), an avian paramyxovirus, causes Newcastle disease (ND) which is a highly contagious and fatal viral disease affecting poultry and most species of birds. The fusion (F) protein of NDV mediates membrane fusion, which is essential to the processes of viral entry, replication, and dissemination. Although several domains of NDV F are known to have important effects on regulating the membrane fusion activity, the role of the region around domain III (DIII) and domain I (DI) still remains ill-defined. Site-directed mutagenesis was utilized to change the conserved amino acids at 269, 274, 277, 286, 287, 290, 295, and 297 to alanine in order to investigate the effects of these conserved amino acids around the DIII and DI linker region of the NDV F protein on fusion activity. It was found that five of these substitutions almost abolished fusion activity except for mutants I269A, Q286A, and N297A, which showed 57.1%, 161.1%, and 97.7% of the wt F level, respectively. Four (I274A, D277A, V287A, and P290A) of these five mutants likely result in interfering with folding or transporting of the molecule since these proteins were minimally expressed at the cell surface, formed aggregates, or not proteolytically cleaved. However, mutant L295A almost abolished fusion activity even with a similar level of cell surface expression. These data indicated that conserved amino acids around the DIII-DI linker region are critical for the folding of the F protein and have an important influence on fusion activity.

Non-Structural Protein 2B of Human Rhinovirus 16 Activates Both PERK and ATF6 Rather Than IRE1 to Trigger ER Stress.

To understand the underlying mechanisms of endoplasmic reticulum (ER) stress caused by human rhinovirus (HRV) 16 and non-structural transmembrane protein 2B, the expressions of ER chaperone glucose-regulated protein 78 (GRP78) and three signal transduction pathways, including protein kinase RNA-like ER kinase (PERK), activating transcription factor 6 (ATF6) and inositol-requiring enzyme 1 (IRE1), were evaluated after HRV16 infection and 2B gene transfection. Our results showed that both HRV16 infection and 2B gene transfection increased the expression of ER chaperone GRP78, and induced phosphorylation of PERK and cleavage of ATF6 in a time-dependent manner. Our data also revealed that the HRV16 2B protein was localized to the ER membrane. However, both HRV16 infection and HRV16 2B gene transfection did not induce ER stress through the IRE1 pathway. Moreover, our results showed that apoptosis occurred in H1-HeLa cells infected with HRV16 or transfected with 2B gene accompanied with increased expression of CHOP and cleaved caspase-3. Taken together, non-structural protein 2B of HRV16 induced an ER stress response through the PERK and ATF6 pathways rather than the IRE1 pathway.

Functional analysis of amino acids at stalk/head interface of human parainfluenza virus type 3 hemagglutinin-neuraminidase protein in the membrane fusion process.

Human parainfluenza virus type 3 (hPIV3) is an important respiratory pathogen that causes the majority of viral pneumonia of infants and young children. hPIV3 can infect host cells through the synergistic action of hemagglutinin-neuraminidase (HN) protein and the homotypic fusion (F) protein on the viral surface. HN protein plays a variety of roles during the virus invasion process, such as promoting viral particles to bind to receptors, cleaving sialic acid, and activating the F protein. Crystal structure research shows that HN tetramer adopted a "heads-down" conformation, at least two heads dimmer on flank of the four-helix bundle stalk, which forms a symmetrical interaction interface. The stalk region determines interactions and activation of F protein in specificity, and the heads in down position statically shield these residues. In order to make further research on the function of these amino acids at the hPIV3 HN stalk/head interface, fifteen mutations (8 sites from stalk and 7 sites from head) were engineered into this interface by site-directed mutagenesis in this study. Alanine substitution in this region of hPIV3 HN had various effects on cell fusion promotion, receptor binding, and neuraminidase activity. Besides, L151A also affected surface protein expression efficiency. Moreover, I112A, D120A, and R122A mutations of the stalk region that were masked by global head in down position had influence on the interaction between F and HN proteins.

Gene expression analysis during recovery process indicates the mechanism for innate immune injury and repair from Coxsackievirus B3-induced myocarditis.

To investigate the innate immune injury and repair mechanism during recovery from Coxsackievirus B3 (CVB3) induced myocarditis, we established an acute viral myocarditis recovery model by infecting BALB/c mice with CVB3. Histopathological examination of cardiac tissues after infection showed a gradual increase of myocardial injury to the maximum degree at 8 dpi (days post infection), followed by a recovery process with reduced viral replication. We also measured expression changes of innate immune genes in heart after 4, 8 and 12 days of infection using innate immune real-time PCR array. The results showed expression alterations in many Pattern Recognition Receptors (PRRs) genes upon CVB3 infection, which activated multiple important signaling pathways during recovery process. The expression of TLRs, RLRs, PKR and cytokines were strongly induced and reached the peak at 4 dpi in early myocarditis stage, followed by a gradual reduction in recovery stage, during which the levels were even lower than normal at 12 dpi. The strong correlation between cardiac histopathology score and chemokine expression level suggested that the chemokines might play a role in pathological changes during early myocarditis stage. In addition, we also found that both cell survival signaling pathways (AKT1, p38MAPK) and antiviral signaling pathways (IKKα/ß/ε) were activated and promoted the recovery during late myocarditis stage. Altogether, our observations improved the understanding of formation and progression of the pathological lesions, as well as the repair mechanism for acute viral myocarditis.

Coxsackievirus B3 2A protease promotes encephalomyocarditis virus replication.

To determine whether 2A protease of the enterovirus genus with type I internal ribosome entry site (IRES) effect on the viral replication of type II IRES, coxsackievirus B3(CVB3)-encoded protease 2A and encephalomyocarditis virus (EMCV) IRES (Type II)-dependent or cap-dependent report gene were transiently co-expressed in eukaryotic cells. We found that CVB3 2A protease not only inhibited translation of cap-dependent reporter genes through the cleavage of eIF4GI, but also conferred high EMCV IRES-dependent translation ability and promoted EMCV replication. Moreover, deletions of short motif (aa13-18 RVVNRH, aa65-70 KNKHYP, or aa88-93 PRRYQSH) resembling the nuclear localization signals (NLS) or COOH-terminal acidic amino acid motif (aa133-147 DIRDLLWLEDDAMEQ) of CVB3 2A protease decreased both its EMCV IRES-dependent translation efficiency and destroy its cleavage on eukaryotic initiation factor 4G (eIF4G) I. Our results may provide better understanding into more effective interventions and treatments for co-infection of viral diseases.