Japanese encephalitis virus NS1 and NS1' protein disrupts the blood-brain barrier through macrophage migration inhibitory factor-mediated autophagy

Flaviviruses in the Japanese encephalitis virus (JEV) serogroup, such as JEV, West Nile virus, and St. Louis encephalitis virus, can cause severe neurological diseases. The nonstructural protein 1 (NS1) is a multifunctional protein of flavivirus that can be secreted by infected cells and circulate in the host bloodstream. NS1' is an additional form of NS1 protein with 52 amino acids extension at its carboxy-terminal and is produced exclusively by flaviviruses in the JEV serogroup. In this study, we demonstrated that the secreted form of both NS1 and NS1' can disrupt the blood-brain barrier (BBB) of mice, with NS1' exhibiting a stronger effect. Using the in vitro BBB model, we found that treatment of soluble recombinant JEV NS1 or NS1' protein increases the permeability of human brain microvascular endothelial cells (hBMECs) and leads to the degradation of tight junction proteins through the autophagy-lysosomal pathway. Consistently, NS1' protein exhibited a more pronounced effect compared to NS1 in these cellular processes. Further research revealed that the increased expression of macrophage migration inhibitory factor (MIF) is responsible for triggering autophagy after NS1 or NS1' treatment in hBMECs. In addition, TLR4 and NF-κB signaling was found to be involved in the activation of MIF transcription. Moreover, administering the MIF inhibitor has been shown to decrease viral loads and mitigate inflammation in the brains of mice infected with JEV. This research offers a novel perspective on the pathogenesis of JEV. In addition, the stronger effect of NS1' on disrupting the BBB compared to NS1 enhances our understanding of the mechanism by which flaviviruses in the JEV serogroup exhibit neurotropism.IMPORTANCEJapanese encephalitis (JE) is a significant viral encephalitis worldwide, caused by the JE virus (JEV). In some patients, the virus cannot be cleared in time, leading to the breach of the blood-brain barrier (BBB) and invasion of the central nervous system. This invasion may result in cognitive impairment, behavioral disturbances, and even death in both humans and animals. However, the mechanism by which JEV crosses the BBB remains unclear. Previous studies have shown that the flavivirus NS1 protein plays an important role in causing endothelial dysfunction. The NS1' protein is an elongated form of NS1 protein that is particularly produced by flaviviruses in the JEV serogroup. This study revealed that both the secreted NS1 and NS1' of JEV can disrupt the BBB by breaking down tight junction proteins through the autophagy-lysosomal pathway, and NS1' is found to have a stronger effect compared to NS1 in this process. In addition, JEV NS1 and NS1' can stimulate the expression of MIF, which triggers autophagy via the ERK signaling pathway, leading to damage to BBB. Our findings reveal a new function of JEV NS1 and NS1' in the disruption of BBB, thereby providing the potential therapeutic target for JE.

Single-cell RNA sequencing reveals the immune features and viral tropism in the central nervous system of mice infected with Japanese encephalitis virus

Japanese encephalitis virus (JEV) is a neurotropic pathogen that causes lethal encephalitis. The high susceptibility and massive proliferation of JEV in neurons lead to extensive neuronal damage and inflammation within the central nervous system. Despite extensive research on JEV pathogenesis, the effect of JEV on the cellular composition and viral tropism towards distinct neuronal subtypes in the brain is still not well comprehended. To address these issues, we performed single-cell RNA sequencing (scRNA-seq) on cells isolated from the JEV-highly infected regions of mouse brain. We obtained 88,000 single cells and identified 34 clusters representing 10 major cell types. The scRNA-seq results revealed an increasing amount of activated microglia cells and infiltrating immune cells, including monocytes & macrophages, T cells, and natural killer cells, which were associated with the severity of symptoms. Additionally, we observed enhanced communication between individual cells and significant ligand-receptor pairs related to tight junctions, chemokines and antigen-presenting molecules upon JEV infection, suggesting an upregulation of endothelial permeability, inflammation and antiviral response. Moreover, we identified that Baiap2-positive neurons were highly susceptible to JEV. Our findings provide valuable clues for understanding the mechanism of JEV induced neuro-damage and inflammation as well as developing therapies for Japanese encephalitis.

Ferroptosis contributes to JEV-induced neuronal damage and neuroinflammation

Ferroptosis is a newly discovered prototype of programmed cell death (PCD) driven by iron-dependent phospholipid peroxidation ​accumulation, and it has been linked to numerous organ injuries and degenerative pathologies. Although studies have shown that a variety of cell death processes contribute to JEV-induced neuroinflammation and neuronal injury, there is currently limited research on the specific involvement of ferroptosis. In this study, we explored the neuronal ferroptosis induced by JEV infection in vitro and in vivo. Our results indicated that JEV infection induces neuronal ferroptosis through inhibiting the function of the antioxidant system mediated by glutathione (GSH)/glutathione peroxidase 4 (GPX4), as well as by promoting lipid peroxidation mediated by yes-associated protein 1 (YAP1)/long-chain acyl-CoA synthetase 4 (ACSL4). Further analyses revealed that JEV E and prM proteins function as agonists, inducing ferroptosis. Moreover, we found that treatment with a ferroptosis inhibitor in JEV-infected mice reduces the viral titers and inflammation in the mouse brains, ultimately improving the survival rate of infected mice. In conclusion, our study unveils a critical role of ferroptosis in the pathogenesis of JEV, providing new ideas for the prevention and treatment of viral encephalitis.

Lung cDC1 and cDC2 dendritic cells priming naive CD8+ T cells in situ prior to migration to draining lymph nodes

The current paradigm indicates that naive T cells are primed in secondary lymphoid organs. Here, we present evidence that intranasal administration of peptide antigens appended to nanofibers primes naive CD8+ T cells in the lung independently and prior to priming in the draining mediastinal lymph node (MLN). Notably, comparable accumulation and transcriptomic responses of CD8+ T cells in lung and MLN are observed in both Batf3KO and wild-type (WT) mice, indicating that, while cDC1 dendritic cells (DCs) are the major subset for cross-presentation, cDC2 DCs alone are capable of cross-priming CD8+ T cells both in the lung and draining MLN. Transcription analyses reveal distinct transcriptional responses in lung cDC1 and cDC2 to intranasal nanofiber immunization. However, both DC subsets acquire shared transcriptional responses upon migration into the lymph node, thus uncovering a stepwise activation process of cDC1 and cDC2 toward their ability to cross-prime effector and functional memory CD8+ T cell responses.

A novel triptolide analog downregulates NF-κB and induces mitochondrial apoptosis pathways in human pancreatic cancer

Pancreatic cancer is the seventh leading cause of cancer-related death worldwide, and despite advancements in disease management, the 5 -year survival rate stands at only 12%. Triptolides have potent anti-tumor activity against different types of cancers, including pancreatic cancer, however poor solubility and toxicity limit their translation into clinical use. We synthesized a novel pro-drug of triptolide, (E)-19-[(1'-benzoyloxy-1'-phenyl)-methylidene]-Triptolide (CK21), which was formulated into an emulsion for in vitro and in vivo testing in rats and mice, and used human pancreatic cancer cell lines and patient-derived pancreatic tumor organoids. A time-course transcriptomic profiling of tumor organoids treated with CK21 in vitro was conducted to define its mechanism of action, as well as transcriptomic profiling at a single time point post-CK21 administration in vivo. Intravenous administration of emulsified CK21 resulted in the stable release of triptolide, and potent anti-proliferative effects on human pancreatic cancer cell lines and patient-derived pancreatic tumor organoids in vitro, and with minimal toxicity in vivo. Time course transcriptomic profiling of tumor organoids treated with CK21 in vitro revealed <10 differentially expressed genes (DEGs) at 3 hr and ~8,000 DEGs at 12 hr. Overall inhibition of general RNA transcription was observed, and Ingenuity pathway analysis together with functional cellular assays confirmed inhibition of the NF-κB pathway, increased oxidative phosphorylation and mitochondrial dysfunction, leading ultimately to increased reactive oxygen species (ROS) production, reduced B-cell-lymphoma protein 2 (BCL2) expression, and mitochondrial-mediated tumor cell apoptosis. Thus, CK21 is a novel pro-drug of triptolide that exerts potent anti-proliferative effects on human pancreatic tumors by inhibiting the NF-κB pathway, leading ultimately to mitochondrial-mediated tumor cell apoptosis.

Allisartan Isoproxil Promotes Uric Acid Excretion by Interacting with Intestinal Urate Transporters in Hyperuricemic Zebrafish (Danio rerio)

To evaluate the urate-lowering effect and potential drug targets of antihypertensive agent allisartan isoproxil (ALI) and its bioactive metabolite EXP3174, we developed an acute hyperuricemic zebrafish model using potassium oxonate and xanthine sodium salt. Losartan potassium served as the positive control (reference drug). In this model, ALI and losartan potassium exerted a greater urate-lowering effect than EXP3174 indicating that the latter is not the critical substance for elimination of uric acid. The quantitative real-time PCR showed that ALI upregulates the expression of intestinal urate transporters genes ABCG2, PDZK1, and SLC2A9 (p<0.01). Thus, we can suggest that this substance promotes uric acid excretion mainly by interacting with intestinal urate transporters.

H3K27me3 of Rnf19a promotes neuroinflammatory response during Japanese encephalitis virus infection

Histone methylation is an important epigenetic modification that affects various biological processes, including the inflammatory response. In this study, we found that infection with Japanese encephalitis virus (JEV) leads to an increase in H3K27me3 in BV2 microglial cell line, primary mouse microglia and mouse brain. Inhibition of H3K27me3 modification through EZH2 knockdown and treatment with EZH2 inhibitor significantly reduces the production of pro-inflammatory cytokines during JEV infection, which suggests that H3K27me3 modification plays a crucial role in the neuroinflammatory response caused by JEV infection. The chromatin immunoprecipitation-sequencing (ChIP-sequencing) assay revealed an increase in H3K27me3 modification of E3 ubiquitin ligases Rnf19a following JEV infection, which leads to downregulation of Rnf19a expression. Furthermore, the results showed that Rnf19a negatively regulates the neuroinflammatory response induced by JEV. This is achieved through the degradation of RIG-I by mediating its ubiquitination. In conclusion, our findings reveal a novel mechanism by which JEV triggers extensive neuroinflammation from an epigenetic perspective.

Development of efficient, sensitive, and specific detection method for Encephalomyocarditis virus based on CRISPR/Cas13a

The Encephalomyocarditis virus (EMCV) is one of the major zoonosis pathogens, and it can cause acute myocarditis in young pigs or reproductive failure in sows. EMCV has been recognized as a pathogen infecting many species and causes substantial economic losses worldwide. Therefore, the development of a rapid, sensitive, and accurate detection of this virus is essential for the diagnosis and control of the EMCV-induced disease. The RNA-guiding, RNA-targeting CRISPR effector CRISPR/Cas13a (Cas13a, previously known as C2c2) exhibits a "collateral effect" of promiscuous RNase activity upon the target recognition. When the crRNA of LwCas13a binds to the target RNA, the collateral cleavage activity of LwCas13a is activated to degrade the non-targeted RNA. In this study, we developed an efficient, sensitive, and specific EMCV detection method based on the collateral cleavage activity of LwCas13a by combining recombinase-aided amplification (RAA) and a lateral flow strip. This method was an isothermal detection at 37 °C, which allowed visual observation by the naked eyes. We also optimized the reaction conditions of this method, and the detection result could be obtained within 60 min. The sensitivity of our method reached up to 10¹ copies/µL. Furthermore, no cross-reactions with other 8 major swine viruses were observed, indicating the excellent specificity of this method. At the same time, the assay had a 100 % coincidence rate with qPCR detection of the EMCV in 37 clinical samples. In addition, our developed method requires only 2-step operations and basic equipment, and thus it is simple and inexpensive. Overall, CRISPR/Cas13a-based detection has a great application potential for the EMCV detection.

Zika virus causes placental pyroptosis and associated adverse fetal outcomes by activating GSDME

Zika virus (ZIKV) can be transmitted from mother to fetus during pregnancy, causing adverse fetal outcomes. Several studies have indicated that ZIKV can damage the fetal brain directly; however, whether the ZIKV-induced maternal placental injury contributes to adverse fetal outcomes is sparsely defined. Here, we demonstrated that ZIKV causes the pyroptosis of placental cells by activating the executor gasdermin E (GSDME) in vitro and in vivo. Mechanistically, TNF-α release is induced upon the recognition of viral genomic RNA by RIG-I, followed by activation of caspase-8 and caspase-3 to ultimately escalate the GSDME cleavage. Further analyses revealed that the ablation of GSDME or treatment with TNF-α receptor antagonist in ZIKV-infected pregnant mice attenuates placental pyroptosis, which consequently confers protection against adverse fetal outcomes. In conclusion, our study unveils a novel mechanism of ZIKV-induced adverse fetal outcomes via causing placental cell pyroptosis, which provides new clues for developing therapies for ZIKV-associated diseases.

Tissue specificity drives protective immunity against Staphylococcus aureus infection

Infections caused by Staphylococcus aureus range from mild to severe and frequently recur. Emerging evidence suggests that the site and severity of infection drive the potency of elicited immune responses and susceptibility to recurrent infection. In this study, we used tractable mouse models of S. aureus skin infection (SSTI) and pneumonia to determine the relative magnitude of elicited protective immunity. Surprisingly, despite both SSTI and pneumonia eliciting antibody and local effector T cell responses, only SSTI elicited protective antibody and memory T cell responses and subsequent protection against secondary SSTI and pneumonia. The failure of pneumonia to elicit protective immunity was attributed to an inability of S. aureus pneumonia to elicit toxin-specific antibodies that confer protection during secondary infection and was associated with a failure to expand antigen-specific memory T cells. Taken together, these findings emphasize the importance of understanding protective immunity in the context of the tissue-specificity.

Protective Immune Responses Induced by an mRNA-LNP Vaccine Encoding prM-E Proteins against Japanese Encephalitis Virus Infection

Japanese encephalitis virus (JEV) is an important zoonotic pathogen, which causes central nervous system symptoms in humans and reproductive disorders in swine. It has led to severe impacts on human health and the swine industry; however, there is no medicine available for treating yet. Therefore, vaccination is the best preventive measure for this disease. In the study, a modified mRNA vaccine expressing the prM and E proteins of the JEV P3 strain was manufactured, and a mouse model was used to assess its efficacy. The mRNA encoding prM and E proteins showed a high level of protein expression in vitro and were encapsulated into a lipid nanoparticle (LNP). Effective neutralizing antibodies and CD8+ T-lymphocytes-mediated immune responses were observed in vaccinated mice. Furthermore, the modified mRNA can protect mice from a lethal challenge with JEV and reduce neuroinflammation caused by JEV. This study provides a new option for the JE vaccine and lays a foundation for the subsequent development of a more efficient and safer JEV mRNA vaccine.

[Otologic disorders and management strategies in Turner syndrome]

Objective: To analyze the incidence and risk factors of otologic disorders in patients with Turner syndrome (TS), so as to provide management strategies for ear health. Methods: This study is a prospective study based on questionnaires and a cross-sectional study. The TS patients who visited our hospital from 2010 January to 2021 March were included (A total of 71 patients with TS were included in this study. the age of TS diagnosed was 3- to 11-year-old, age of visiting ENT department was 4- to 27-year-old) and the incidence of otologic diseases in different age groups was investigated by questionnaires. The cross-sectional study included ear morphology and auditory function assessment, and further analysis of the risk factors that related to ear disease. Prism was used for data analysis. Results: The investigation found that the incidence of acute otitis media in patients aged 3-6 and 7-12 years was higher than that of patients over 12 years old, which was 33.8%(24/71), 42.9%(30/70)and 23.5%(8/34), respectively; 21.1% (15/71) of patients were recurrent acute otitis media in patients aged 3-6 years, and about 46.6% (7/15)of them persisted beyond 6-year. The prevalence of otitis media with effusion in the three groups was 32.4%(23/71), 34.3%(24/70)and 38.2%(13/34), respectively; the recurrence rate of tympanocentesis was 100%(7/7), 42.9%(3/7)and 50.0%(1/2), which was significantly higher than that of grommet insertion. For age groups of 3-6 and 7-12 years, the prevalence of acute otitis media and secretory otitis media was lower in the X chromosome structure abnormal patients; while for patients older than 12 years, otitis media with effusion was the highest prevalence in Y-chromosome-containing karyotypes. In addition, the prevalence of acute otitis media and otitis media with effusion in patients with other system diseases were increased significantly. A cross-sectional study found that 7.0% (5/71)of the lower auricular, 4.2% (3/71)of the external auditory canal narrow, and 38.0% (27/71)of the tympanic membrane abnormality. 35.2%(25/71) had abnormal hearing, including 17 cases of conductive deafness, 6 cases of sensorineural hearing loss, and 2 cases of mixed deafness. The rest of the patients had normal hearing, but 6 of them had abnormalities in otoacoustic emission. Eustachian tube function assessment found that the eustachian tube dysfunction accounted for 38%(27/71). Hearing loss and abnormal Eustachian tube function were not significantly related to karyotype(Chi-square 2.83 and 2.84,P value 0.418 and 0.417), but significantly related to other system diseases(Chi-square 13.43 and 7.53,P value<0.001). Conclusions: The incidence of TS-related otitis media and auditory dysfunction is significantly higher than that of the general population. It not only occurs in preschool girls, but also persists or develops after school age. Accompanied by other system diseases are risk factors for ear diseases. Clinicians should raise their awareness of TS-related ear diseases and incorporate ear health monitoring into routine diagnosis and treatment.

Iodine Maps from Dual-Energy CT to Predict Extrathyroidal Extension and Recurrence in Papillary Thyroid Cancer Based on a Radiomics Approach

BACKGROUND AND PURPOSE

Accurate prediction of extrathyroidal extension and subsequent recurrence is crucial in papillary thyroid cancer clinical management. Our aim was to conduct iodine map-based radiomics to predict extrathyroidal extension and to explore its prognostic value for recurrence-free survival in papillary thyroid cancer.

MATERIALS AND METHODS

A total of 452 patients with papillary thyroid cancer were retrospectively recruited between June 2017 and June 2020. Radiomics features were extracted from noncontrast images, dual-phase mixed images, and iodine maps, respectively. Random forest and least absolute shrinkage and selection operator (LASSO) were applied to build 6 radiomics scores (noncontrast radiomics score_random forest; noncontrast rad-score_LASSO; mixed rad-score_random forest; mixed rad-score_LASSO; iodine radiomics score_random forest; iodine radiomics score_LASSO) respectively. Logistic regression was used to construct 6 radiomics models incorporating 6 radiomics scores with clinical risk factors and to compare them with the clinical model. A radiomics model that achieved the highest performance was presented as a nomogram and assessed by discrimination, calibration, clinical usefulness, and prognosis evaluation.

RESULTS

Iodine radiomics scores performed significantly better than mixed radiomics scores. Both of them outperformed noncontrast radiomics scores. Iodine map-based radiomics models significantly surpassed the clinical model. A radiomics nomogram incorporating size, capsule contact, and iodine radiomics score_random forest was built with the highest performance (training set, area under the curve = 0.78; validation set, area under the curve  = 0.84). Stratified analysis confirmed the nomogram stability, especially in group negative for CT-reported extrathyroidal extension (area under the curve  = 0.69). Nomogram-predicted extrathyroidal extension risk was an independent predictor of recurrence-free survival. A high risk for extrathyroidal extension portended significantly lower recurrence-free survival than low risk (P < .001).

CONCLUSIONS

Iodine map-based radiomics might be a supporting tool for predicting extrathyroidal extension and subsequent recurrence risk in patients with papillary thyroid cancer, thus facilitating clinical decision-making.

Epidemiology and Comparative Analyses of the S Gene on Feline Coronavirus in Central China

Feline coronavirus (FCoV) infections present as one of two forms: a mild or symptom-less enteric infection (FEC) and a fatal systemic disease termed feline infectious peritonitis (FIP). The lack of epidemiology of FCoV in central China and the reason why different symptoms are caused by viruses of the same serotype have motivated this investigation. Clinical data of 81 suspected FIP cases, 116 diarrhea cases and 174 healthy cases were collected from veterinary hospitals using body cavity effusion or fecal samples. Risk factors, sequence comparison and phylogenetic studies were performed. The results indicated that FIPV was distinguished from FECV in the average hydrophobicity of amino acids among the cleavage sites of furin, as well as the mutation sites 23,531 and 23,537. FIPV included a higher minimal R-X-X-R recognition motif of furin (41.94%) than did FECV (9.1%). The serotype of FCoV was insignificantly correlated with FIP, and the clade 1 and clade 2 strains that appeared were unique to central China. Thus, it is hypothesized that this, along with the latent variables of an antigenic epitope at positions 1058 and 1060, as well as mutations at the S1/S2 sites, are important factors affecting FCoV transmission and pathogenicity.

Rapid Detection of Genotype II African Swine Fever Virus Using CRISPR Cas13a-Based Lateral Flow Strip

The African swine fever virus (ASFV) is a dsDNA virus that can cause serious, highly infectious, and fatal diseases in wild boars and domestic pigs. The ASFV has brought enormous economic loss to many countries, and no effective vaccine or treatment for the ASFV is currently available. Therefore, the on-site rapid and accurate detection of the ASFV is key to the timely implementation of control. The RNA-guided, RNA-targeting CRISPR effector CRISPR-associated 13 (Cas13a; previously known as C2c2) exhibits a “collateral effect” of promiscuous RNase activity upon the target recognition. The collateral cleavage activity of LwCas13a is activated to degrade the non-targeted RNA, when the crRNA of LwCas13a binds to the target RNA. In this study, we developed a rapid and sensitive ASFV detection method based on the collateral cleavage activity of LwCas13a, which combines recombinase-aided amplification (RAA) and a lateral flow strip (named CRISPR/Cas13a-LFD). The method was an isothermal detection at 37 °C, and the detection can be used for visual readout. The detection limit of the CRISPR/Cas13a-LFD was 101 copies/µL of p72 gene per reaction, and the detection process can be completed within an hour. The assay showed no cross-reactivity to eight other swine viruses, including classical swine fever virus (CSFV), and has a 100% coincidence rate with real-time PCR detection of the ASFV in 83 clinical samples. Overall, this method is sensitive, specific, and practicable onsite for the ASFV detection, showing a great application potential for monitoring the ASFV in the field.

Ethnic Disparities in Dental Caries among Adolescents in China

Comprehensive research on ethnic disparities in dental caries in China is limited. The aims of this cross-sectional study were to compare the levels of dental caries in adolescents between the Han ethnic group and ethnic minority groups in China and to explore the risk indicators for dental caries within ethnic subgroups. Data from the Fourth National Oral Health Survey in 2015, which covered all 31 province-level administrative divisions in mainland China, were used. The dental caries status in the permanent dentition of adolescents aged 12, 13, 14, and 15 y was measured using the decayed, missing, and filled teeth (DFMT) score, and sociodemographic characteristics and oral health-related behaviors were also collected. A total of 118,601 adolescents were included, with ethnic minority groups accounting for 13.15%. Of the Han and minority groups, the standardized prevalence of dental caries experience was 40.58% and 47.67%, and the mean DMFT scores were 0.97 and 1.28, respectively. According to the multivariate zero-inflated negative binomial regression analysis, the caries status of minorities was more severe than Han adolescents (adjusted prevalence rate ratio [PRR], 1.14; 95% confidence interval [CI], 1.10-1.18). This disparity was greater among adolescents who lived in rural areas, had mid-level economic status, and frequently consumed sugary beverages. After propensity score matchings, Uygur (PRR, 1.44; 95% CI, 1.25-1.67), Tibetan (PRR, 1.39; 95% CI, 1.3-1.48), and Yi (PRR, 1.24; 95% CI, 1.04-1.48) adolescents were significantly more likely to have caries than Han adolescents. Subgroup analyses revealed that gender, age, location of residence, economic status, region, consumption of sweet snacks and sugary beverages, and dental visit pattern were significantly associated with dental caries within ethnic minorities.

Adjuvant-free nanofiber vaccine induces in situ lung dendritic cell activation and TH17 responses

The current paradigm that subunit vaccines require adjuvants to optimally activate innate immunity implies that increased vaccine reactogenicity will invariably be linked to improved immunogenicity. Countering this paradigm, nanoparticulate vaccines have been reported to act as delivery systems for vaccine antigens and induce immunity without the need for exogenous adjuvants or local inflammation; however, the mechanisms underlying the immunogenicity of nanoparticle vaccines are incompletely identified. Here, we show that antigens displayed on self-assembling nanofiber scaffolds and delivered intranasally are presented by CD103⁺ and CD11b⁺ lung dendritic cells that up-regulate CD80 and migrate into the draining lymph node (LN). This was accompanied by a nearly exclusive priming and accumulation of antigen-specific T_H17 cells occurring independently in both LN and lung. Thus, self-assembling peptide nanofiber vaccines may represent a novel, needle- and adjuvant-free means of eliciting protective immunity against fungal and bacterial infections at skin and mucosal barrier surfaces.

Inhibition of protective immunity against Staphylococcus aureus infection by MHC-restricted immunodominance is overcome by vaccination

Recurrent Staphylococcus aureus infections are common, despite robust immune responses. S. aureus infection elicited protective antibody and T cell responses in mice that expressed the Major Histocompatibility Complex (MHC) of the H-2^d haplotype, but not H-2^b, demonstrating that host genetics drives individual variability. Vaccination with a-toxin or leukotoxin E (LukE) elicited similar antibody and T cell responses in mice expressing H-2^d or H-2^b, but vaccine-elicited responses were inhibited by concomitant infection in H-2^d-expressing mice. These findings suggested that competitive binding of microbial peptides to host MHC proteins determines the specificity of the immunodominant response, which was confirmed using LukE-derived peptide-MHC tetramers. A vaccine that elicited T cell and antibody responses protected mice that expressed H-2^d or H-2^b, demonstrating that vaccination can overcome MHC-restricted immunodominance. Together, these results define how host genetics determine whether immunity elicted by S. aureus is protective and provide a mechanistic roadmap for future vaccine design.

[Countermeasures and treatment for aortic acute syndrome with novel coronavirus pneumonia]

The novel coronavirus pneumonia (NCP) has cost a great loss to the health and economic property of Chines people. Under such a special circumstance, how to deal with such patients with acute aortic syndrome has become a serious challenge. Rapid diagnosis of concomitant NCP, safe and effective transportation, implementation of the interventional procedure, protection of vascular surgical team and postoperative management and follow-up of such patients have become urgent problems for us. Combined with the latest novel government documents, the literature and the experiences from Wuhan, we answered the above questions briefly and plainly. It also hopes to inspire the national vascular surgeons to manage critical emergencies in vascular surgery and even routine vascular diseases with NCP, as a final point to limit the severe epidemic situation, and minimize the damage of NCP.

[Biomechanical changes of sheep cervical spine after unilateral hemilaminectomy and different degrees of facetectomy]

OBJECTIVE

To establish animal models and investigate the impact of unilateral hemilaminectomy (ULHL) and different degrees of facetectomy (FT) on the cervical spinal biomechanics.

METHODS

Twenty sheep were randomly and evenly divided into 4 groups. No operation was performed for group A, right C4-C6 ULHL was performed for group B, right C4-C6 ULHL and 50% ipsilateral C4-C5 FT was performed for group C, right C4-C6 ULHL and 100% ipsilateral C4-C5 FT was performed for group D. Animals of group A, B, C and D were sacrificed 24 weeks after operating and fresh cervical spine specimens were acquired, biomechanically tested and these data were compared to determine whether ULHL and different degrees of FT led to long-term differences in range of motion.

RESULTS

(1) Changes of the total range of motion of cervical spine 24 weeks after surgery: the total range of motion of group D (60.2°±8.6°) was significantly greater than group A (40.7°±6.4°) and group B (41.2°±13.1°) under flexion-extension station, the total range of motion of group D (81.5°±15.7°) was significantly greater than that of group A (56.7°±12.2°) and group B (57.7°±12.8°) under lateral bending station, and the total range of motion of group D (38.5°±17.5°) had no obvious increase compared with group A (26.4°±9.9°) and group B (27.1°±10.9°) under axial rotation station. The total range of motion of group C had no obvious increase compared with group A and group B under flexion-extension station (44.1°±11.7°), lateral bending station (73.6°±11.4°) and axial rotation station (31.3°±11.5°). (2) Changes of the intersegmental motion 24 weeks after surgery: the intersegmental motion of group D (20.3°±4.6°) at C4-C5 was significantly greater than that of group A (11.7°±3.4°) and group B (11.9°±2.1°) under flexion-extension station, the intersegmental motion of group D (26.8°±3.5°) at C4-C5 was significantly greater than that of group A (15.2°±3.1°) and group B (16.2°±3.2°) under lateral bending station, the intersegmental motion of group D (15.2°±3.5°) at C4-C5 was significantly greater than that of group A (6.6°±2.3°) and group B (7.1°±1.9°) under axial rotation station. The intersegmental motion of group C (21.2°±4.1°) at C4-C5 was significantly greater than that of group A and group B under lateral bending station, the intersegmental motion of group C at C4-C5 had no obvious increase compared with group A and group B under flexion-extension station (15.7°±3.7°) and axial rotation station (10.3°±3.1°).

CONCLUSION

ULHL does not affect cervical stability, ULHL and 50% ipsilateral FT does not affect the long-term cervical stability, ULHL and 100% ipsilateral FT can lead to long-term instability under lateral bending and flexion-extension station.

Clinical, neuroimaging and prognostic study of 127 cases with infarction of the corpus callosum

Background and purpose

The aim of this study was to retrospectively investigate clinical and neuroimaging characteristics in the largest sample size of patients with corpus callosum infarction to date and then to follow up these patients for 1 year to clarify the prognosis of this rare stroke entity.

Methods

A total of 127 patients with acute callosal infarction out of 5584 acute ischaemic stroke patients were included in this study. The recruited patients were divided into a pure callosal infarction group and a complex callosal infarction group (coupled with other infarct locations simultaneously), and clinical and neuroimaging features were analyzed. Some of the patients were followed up for 1 year to evaluate recurrence rate and mortality.

Results

The incidence of acute callosal infarction was 2.3%. Most patients presented with advanced neurological dysfunction with or without mild to moderate motor or sensory disorders on admission. The negative rate of computed tomography scan was still 76.4% even at >24 h after onset. Large‐artery atherosclerosis was the most common etiological type. Compared with complex callosal infarction, the pure callosal infarction group had more mental disorders (P = 0.030). Compared with common basal ganglia infarction, the pure callosal infarction group had better short‐term recovery (P = 0.016) but higher 1‐year mortality (P = 0.037). Age and mental disorders were independent risk factors for death in callosal infarction.

Conclusions

Callosal infarction is a white matter stroke that occurs with low incidence. Elderly patients with vascular risk factors showed sudden mental or cognitive disorders and callosal infarction could not be excluded. More attention should be paid to the early diagnosis and secondary prevention of callosal infarction because of its poor long‐term outcome.

Dexmedetomidine attenuation of renal ischaemia-reperfusion injury requires sirtuin 3 activation

BACKGROUND

Dexmedetomidine attenuates renal ischaemia and reperfusion (I/R) injury, but its mechanism of action is unclear. As sirtuin 3 (SIRT3) activation can alleviate acute kidney injury, we investigated whether dexmedetomidine acts through SIRT3 to reduce renal I/R injury.

METHODS

The potential involvement of SIRT3 in dexmedetomidine attenuation of renal I/R injury was tested in HK2 cells subjected to hypoxia/reoxygenation and C57BL/6J mice subjected to renal I/R. A short interfering RNA targeting SIRT3 was used in some experiments to examine the potential role of SIRT3. Cell death and mitochondrial membrane potential (Δψm) were analysed in cultured cells. Mitochondrial damage in mice was assessed using electron microscopy and markers for renal function. Expression of cyclophilin D, cytochrome c, and SIRT3, and the level of cyclophilin D acetylation were determined.

RESULTS

Hypoxia/reoxygenation of HK2 cells increased cell death, cytochrome C expression, and cyclophilin D acetylation, and decreased Δψm and SIRT3 expression (P<0.05). Dexmedetomidine attenuated these changes. The dexmedetomidine effects were enhanced by SIRT3 overexpression and eliminated by SIRT3 knockdown. I/R in mice damaged renal function, and increased histological lesions, mitochondrial damage, cytochrome c expression, and cyclophilin D acetylation, while SIRT3 activity was decreased by 51% (P<0.05). Dexmedetomidine inhibited these changes in mice expressing normal levels of SIRT3, but not in SIRT3-knockdown mice.

CONCLUSIONS

Dexmedetomidine appears to act, at least in part, by up-regulating SIRT3 to inhibit mitochondrial damage and cell apoptosis and thereby protect against renal I/R injury.

Downregulation of HCN1 channels in hippocampus and prefrontal cortex in methamphetamine re-exposed mice with enhanced working memory

The hyperpolarization-activated cyclic-nucleotide-gated non-selective cation (HCN) channels play a potential role in the neurological basis underlying drug addiction. However, little is known about the role of HCN channels in methamphetamine (METH) abuse. In the present study, we examined the changes in working memory functions of METH re-exposed mice through Morris water maze test, and investigated the protein expression of HCN1 channels and potential mechanisms underlying the modulation of HCN channels by Western blotting analysis. Mice were injected with METH (1 mg/kg, i.p.) once per day for 6 consecutive days. After 5 days without METH, mice were re-exposed to METH at the same concentration. We found that METH re-exposure caused an enhancement of working memory, and a decrease in the HCN1 channels protein expression in both hippocampus and prefrontal cortex. The phosphorylated extracellular regulated protein kinase 1/2 (p-ERK1/2), an important regulator of HCN channels, was also obviously reduced in hippocampus and prefrontal cortex of mice with METH re-exposure. Meanwhile, acute METH exposure did not affect the working memory function and the protein expressions of HCN1 channels and p-ERK1/2. Overall, our data firstly showed the aberrant protein expression of HCN1 channels in METH re-exposed mice with enhanced working memory, which was probably related to the down-regulation of p-ERK1/2 protein expression.

Intranasal delivery of adjuvant-free peptide nanofibers elicits resident CD8+ T cell responses

Influenza vaccines that can be administered intranasally or by other needle-free delivery routes have potential advantages over injected formulations in terms of patient compliance, cost, and ease of global distribution. Supramolecular peptide nanofibers have been investigated previously as platforms for vaccines and immunotherapies and have been shown to raise immune responses in the absence of exogenous adjuvants and without measurable inflammation. However, at present it has not been tested whether the immunogenicity of these materials extends to the intranasal route. Here we investigated the extent to which self-assembled peptide nanofibers bearing an influenza peptide epitope elicit antigen-specific CD8+ T cell responses when delivered intranasally, and we compared these responses with those elicited by subcutaneous immunization. Peptides containing an epitope from influenza acid polymerase (PA) and the Q11 self-assembly domain formed nanofibers that were avidly taken up by dendritic cells in lung-draining mediastinal lymph nodes after intranasal immunization. Intranasally delivered nanofibers generated greater antigen-specific CD8+ T cell responses in the lung-draining lymph nodes than subcutaneous immunizations while retaining the non-inflammatory character of the materials observed in other delivery sites. The CD8+ T cells elicited systemically were functional as assessed by their ability to produce IFN-γ ex vivo, lyse epitope-pulsed target cells in vivo, and diminish viral loads in infected mice. Compared to subcutaneously delivered nanofibers, intranasally delivered peptide nanofibers significantly increased the number of persisting antigen-specific tissue resident memory CD8+ T cells in the lung, allowing for a more rapid response to infection at 6 weeks post-vaccination. These results indicate that intranasally delivered self-assembled peptide nanofibers are immunogenic when delivering CD8+ epitopes without adjuvant or CD4+ epitopes, are non-inflammatory, and promote more lung-resident memory CD8+ T cells compared to subcutaneous immunization.

MyD88 in antigen-presenting cells is not required for CD4+ T-cell responses during peptide nanofiber vaccination

Self-assembled peptide nanofibers raise significant antibody and T cell responses without adjuvants, but the mechanism by which they achieve this has not been fully elucidated. Myeloid differentiation primary response gene 88 (MyD88) previously has been shown to be critical for the antibody response to antigens presented by peptide nanofibers. The present study sought to determine the cell subset in which MyD88 is essential for T cell responses. Mice deficient in MyD88 or CD11c⁺ cells had severely attenuated T cell responses. However, mice lacking MyD88 in only CD11c⁺ cells remained capable of internalizing, processing, and presenting nanofiber-derived epitopes to stimulate T cell responses. The necessity of inflammasome pathway was ruled out. Using adoptive transfer models where MyD88 was eliminated in CD4⁺ T cells or in the host, we observed that deficiency only in T cells or only in the host had no impact on the T cell response to nanofiber vaccines. Therefore, knocking out MyD88 in either antigen presenting cells (APCs) or CD4 T cells could not compromise the CD4 T cell responses, suggesting that self-assembled peptide nanofibers trigger redundant MyD88-dependent and MyD88-independent signaling pathways in APCs and T cells. Similar redundancy has been observed for other adjuvants, and this is discussed.

[Utilization of dental services for children: a review of the influencing factors and the possible improvements]

It has been reported that children's oral health conditions are correlated with their attendance to dental health services. Evaluating the influencing factors of utilization of dental services for children may give ways to improve the services per se, and furtherly the children's oral health. The present review retrieved and summarized domestic and foreign studies on the utilization of oral health services for children based on the Andersen behavior model. It was concluded that the utilization of dental services for children was affected by demographic characteristics, social structure, health belief, family factors, community factors and perceived/evaluated needs. To improve the utilization of dental services for children, effort should be made by means of changing caregivers' health belief, developing oral health insurance system, setting up regular oral health resources and increasing the financial support for oral health services by government.

Extracellular DNA traps released by acute promyelocytic leukemia cells through autophagy

Acute promyelocytic leukemia (APL) cells exhibit disrupted regulation of cell death and differentiation, and therefore the fate of these leukemic cells is unclear. Here, we provide the first evidence that a small percentage of APL cells undergo a novel cell death pathway by releasing extracellular DNA traps (ETs) in untreated patients. Both APL and NB4 cells stimulated with APL serum had nuclear budding of vesicles filled with chromatin that leaked to the extracellular space when nuclear and cell membranes ruptured. Using immunofluorescence, we found that NB4 cells undergoing ETosis extruded lattice-like structures with a DNA-histone backbone. During all-trans retinoic acid (ATRA)-induced cell differentiation, a subset of NB4 cells underwent ETosis at days 1 and 3 of treatment. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were significantly elevated at 3 days, and combined treatment with TNF-α and IL-6 stimulated NB4 cells to release ETs. Furthermore, inhibition of autophagy by pharmacological inhibitors or by small interfering RNA against Atg7 attenuated LC3 autophagy formation and significantly decreased ET generation. Our results identify a previously unrecognized mechanism for death in promyelocytes and suggest that ATRA may accelerate ET release through increased cytokines and autophagosome formation. Targeting this cellular death pathway in addition to conventional chemotherapy may provide new therapeutic modalities for APL.

[Scalp surface skin grafts in reconstruction of external auditory meatus in congenital aural atresia]

OBJECTIVE

To investigate the clinical application of scalp skin grafts in reconstruction of external auditory meatus in congenital aural atresia.

METHODS

We conducted a retrospective study on 85 patients of congenital aural atresia, all of whom were unilateral, operated from March of 2008 to December of 2010 in ENT department of the Sun Yat-Sen Memorial Hospital. The patients enrolled in the study were between 6 to 37 years old (median age 12 years), 55 male and 30 female. Scalp surface graft in ipsilateral temporal region was harvested to cover the bony external auditory meatus.

RESULTS

All of these scalp split-thickness skin grafts survived without necrosis, no restenosis was found in these external auditory meatus. Neither scar nor alopecia was found in the skin-harvesting region, and hairs grew well. Granulations occurred in 27 cases in the first to sixth month posteroperatively, 20 cases recovered after local treatment. In the first year, 30 cases obtained hearing improvement more than 15 dB, 36 cases gained more than 25 dB and 19 cases gained more than 35 dB. Totally 8 patients were lost in the 4 to 5 years of follow-up, 70 cases (70/77, 90.9%) developed new external auditory meatus, 7 cases (7/77, 9.1%) suffered from stenosis in different degrees, but no atresia was found in these patients.

CONCLUSION

Scalp split-thickness skin grafts has significant clinical advantage in meatoplasty of congenital aural atresia.

Association of serum level of growth differentiation factor 15 with liver cirrhosis and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) and liver cirrhosis are associated with high mortality worldwide. Currently, alpha-fetoprotein (AFP) is used as a standard serum marker for the detection of HCC, but its sensitivity and specificity are unsatisfactory, and optimal diagnostic markers for cirrhosis are lacking. We previously reported that growth differentiation factor 15 (GDF15) was significantly induced in HCV-infected hepatocytes. This study aimed to investigate GDF15 expression and its correlation with hepatitis virus-related liver diseases. A total of 412 patients with various liver diseases were studied. Healthy and Mycobacterium tuberculosis-infected subjects were included as controls. Serum and tissue GDF15 levels were measured. Serum GDF15 levels were significantly increased in patients with HCC (6.66±0.67 ng/mL, p<0.0001) and cirrhosis (6.51±1.47 ng/mL, p<0.0001) compared with healthy controls (0.31±0.01 ng/mL), though the GDF15 levels in HBV and HCV carriers were moderately elevated (1.34±0.19 ng/mL and 2.13±0.53 ng/mL, respectively). Compared with HBV or HCV carriers, GDF15 had a sensitivity of 63.1% and a specificity of 86.6% at the optimal cut-off point of 2.463 ng/mL in patients with liver cirrhosis or HCC. In HCC patients, the area under the receiver operating curve was 0.84 for GDF15 and 0.76 for AFP, but 0.91 for the combined GDF15 and AFP. Serum GDF15 levels did not significantly differ between the high-AFP and low-AFP groups. GDF15 protein expression in HCC was significantly higher than that in the corresponding adjacent paracarcinomatous tissue and normal liver. Using a combination of GDF15 and AFP will improve the sensitivity and specificity of HCC diagnosis. Further research and the clinical implementation of serum GDF15 measurement as a biomarker for HCC and cirrhosis are recommended.

A novel small-molecule inhibitor of hepatitis C virus replication acts by suppressing signal transducer and activator of transcription 3

OBJECTIVES

Hepatitis C virus (HCV) infects hepatocytes and causes liver damage. The aim of this study was to identify new classes of host-targeting anti-HCV compounds that may provide novel approaches for antiviral treatment regimens.

METHODS

Cell culture-derived HCV (HCVcc), replicons and pseudoparticles were used in combination with high-throughput screening, reporter gene assays and cytotoxicity and signalling pathway analyses.

RESULTS

A small-molecule inhibitor of HCV, N-(cyclopropyl(phenyl)methyl)thieno[2,3-d]pyrimidin-4-amine, designated IB-32, was identified by screening a compound library with a Jc1-luc HCVcc assay. By using various virus models, HCV replication was identified as the predominant step of IB-32's action. IB-32 inhibited HCVcc (genotype 2a) and HCV replicons (genotype 1b) at low nanomolar ranges (with IC50s of 40 ± 8 and 100 ± 15 nM, respectively). IB-32 was found to be non-toxic when tested against a panel of human cell lines in vitro at the effective antiviral dose. Mechanistically, IB-32 strongly inhibited STAT3 (Tyr705) phosphorylation, a necessary cellular factor for HCV replication and a pivotal therapeutic target for multiple cancers. Furthermore, the inhibition of HCV replication by IB-32 was augmented in cells with STAT3 knockdown. In contrast, the inhibitory effect of IB-32 was attenuated in cells overexpressing a constitutively active form of STAT3.

CONCLUSION

The results presented here identify a promising STAT3-targeting anti-HCV therapeutic candidate. This novel small molecule could be further optimized and developed for use as both an antiviral and an anti-cancer drug.

Entry properties and entry inhibitors of a human H7N9 influenza virus

The recently identified human infections with a novel avian influenza H7N9 virus in China raise important questions regarding possible risk to humans. However, the entry properties and tropism of this H7N9 virus were poorly understood. Moreover, neuraminidase inhibitor resistant H7N9 isolates were recently observed in two patients and correlated with poor clinical outcomes. In this study, we aimed to elucidate the entry properties of H7N9 virus, design and evaluate inhibitors for H7N9 virus entry. We optimized and developed an H7N9-pseudotyped particle system (H7N9pp) that could be neutralized by anti-H7 antibodies and closely mimicked the entry process of the H7N9 virus. Avian, human and mouse-derived cultured cells showed high, moderate and low permissiveness to H7N9pp, respectively. Based on influenza virus membrane fusion mechanisms, a potent anti-H7N9 peptide (P155-185-chol) corresponding to the C-terminal ectodomain of the H7N9 hemagglutinin protein was successfully identified. P155-185-chol demonstrated H7N9pp-specific inhibition of infection with IC₅₀ of 0.19 µM. Importantly, P155-185-chol showed significant suppression of A/Anhui/1/2013 H7N9 live virus propagation in MDCK cells and additive effects with NA inhibitors Oseltamivir and Zanamivir. These findings expand our knowledge of the entry properties of the novel H7N9 viruses, and they highlight the potential for developing a new class of inhibitors targeting viral entry for use in the next pandemic.

TGF-β/Smad3 inhibit vascular smooth muscle cell apoptosis through an autocrine signaling mechanism involving VEGF-A

We have previously shown that in the presence of elevated Smad3, transforming growth factor-β (TGF-β) transforms from an inhibitor to a stimulant of vascular smooth muscle cell (SMC) proliferation and intimal hyperplasia (IH). Here we identify a novel mechanism through which TGF-β/Smad3 also exacerbates IH by inhibiting SMC apoptosis. We found that TGF-β treatment led to inhibition of apoptosis in rat SMCs following viral expression of Smad3. Conditioned media from these cells when applied to naive SMCs recapitulated this effect, suggesting an autocrine pathway through a secreted factor. Gene array of TGF-β/Smad3-treated cells revealed enhanced expression of vascular endothelial growth factor (VEGF), a known inhibitor of endothelial cell apoptosis. We then evaluated whether VEGF is the secreted mediator responsible for TGF-β/Smad3 inhibition of SMC apoptosis. In TGF-β/Smad3-treated cells, VEGF mRNA and protein as well as VEGF secretion were increased. Moreover, recombinant VEGF-A inhibited SMC apoptosis and a VEGF-A-neutralizing antibody reversed the inhibitory effect of conditioned media on SMC apoptosis. Stimulation of SMCs with TGF-β led to the formation of a complex of Smad3 and hypoxia-inducible factor-1α (HIF-1α) that in turn activated the VEGF-A promoter and transcription. In rat carotid arteries following arterial injury, Smad3 and VEGF-A expression were upregulated. Moreover, Smad3 gene transfer further enhanced VEGF expression as well as inhibited SMC apoptosis. Finally, blocking either the VEGF receptor or Smad3 signaling in injured carotid arteries abrogated the inhibitory effect of Smad3 on vascular SMC apoptosis. Taken together, our study reveals that following angioplasty, elevation of both TGF-β and Smad3 leads to SMC secretion of VEGF-A that functions as an autocrine inhibitor of SMC apoptosis. This novel pathway provides further insights into the role of TGF-β in the development of IH.

High-throughput profiling of alpha interferon- and interleukin-28B-regulated microRNAs and identification of let-7s with anti-hepatitis C virus activity by targeting IGF2BP1

Hepatitis C virus (HCV) infection is a major cause of severe liver disease. Interferon (IFN)/ribavirin treatment remains the standard therapeutic regimen for HCV infection in most countries. IFN-stimulated genes are believed to contribute to antiviral effects. However, emerging evidence suggests that microRNAs (miRNAs), a class of noncoding small RNAs, are involved in the control of viral infection. Here, we systematically profiled the hepatocyte expression of a set of 750 miRNAs in response to alpha interferon (IFN-α) and interleukin-28B (IL-28B) treatments. The anti-HCV activity of differentially expressed miRNAs was evaluated using cell culture-derived HCV in vitro. The results demonstrate that let-7b had a significant anti-HCV effect by inhibiting HCV replication and viral protein translation in human hepatoma cells. In particular, we show that the inhibition of let-7b attenuated the anti-HCV effects of IFN-α and IL-28B. Furthermore, we show that the host factor insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is a target of let-7b. IGF2BP1 was required for HCV replication, and its expression was downregulated by IFN-α and IL-28B. Deletion of the wild-type seed region of let-7b abolished its antiviral activity. Finally, we demonstrate that other let-7 family miRNAs were able to inhibit HCV and to suppress IGF2BP1 expression. In conclusion, we provide an example of a host miRNA regulated by type I and type III IFNs that inhibits HCV replication and infectivity by targeting host targets. These results highlight the important role of miRNAs in the host antiviral immune response and provide a novel candidate for anti-HCV therapy.

Albumin fusion of interleukin-28B: production and characterization of its biological activities and protein stability

The cytokine interleukin-28B (IL-28B) has potential antiviral properties and regulatory roles in adaptive cellular immunity. A genome-wide association study identified a single nucleotide polymorphism near the IL-28B gene that strongly predicts response to hepatitis C treatment with interferon and ribavirin. In this study, we produced human serum albumin (HSA) fused to interleukin-28B (HSA-IL28B) in an attempt to determine the effects of albumin fusion on anti-Hepatitis C virus (HCV) activity and protein stability. HSA-IL28B was expressed at high levels in the yeast expression system we used and was easily purified. The biological activities of IL-28B were only retained when HSA was fused at the N-terminus. Compared with the native IL-28B, HSA-IL28B showed improved protein stability. HSA-IL28B inhibited HCV infection through the membrane receptors IL28R1 and IL10R2. Additionally, we demonstrated that HSA-IL28B was able to induce interferon-stimulated genes, phosphorylate intracellular STAT1, and act in restricted cell types. Our findings highlight the potential clinical applications of the fusion protein during virus infection and for immune regulation.

Screening and rational design of hepatitis C virus entry inhibitory peptides derived from GB virus A NS5A

Chronic infection by hepatitis C virus (HCV) is a cause of the global burden of liver diseases. HCV entry into hepatocytes is a complicated and multistep process that represents a promising target for antiviral intervention. The recently reported amphipathic α-helical virucidal peptide (C5A) from the HCV NS5A protein suggests a new category of antiviral drug candidates. In this study, to identify C5A-like HCV inhibitors, synthetic peptides derived from the C5A-corresponding NS5 protein region of selected Flaviviridae viruses were evaluated for their anti-HCV activities. A peptide from GB virus A (GBV-A), but not other flaviviruses, demonstrated an inhibitory effect on HCV infection. Through a series of sequence optimizations and modifications of the peptide helicity and hydrophobicity, we obtained a peptide designated GBVA10-9 with highly potent anti-HCV activity. GBVA10-9 suppressed infection with both cell culture-derived and pseudotyped HCV in vitro, and the 50% cell culture inhibitory concentration ranged from 20 nM to 160 nM, depending on the genotypic origin of the envelope proteins. GBVA10-9 had no detectable effects on either HCV attachment to Huh7.5.1 cells or viral RNA replication. No virucidal activity was found with GBVA10-9, suggesting an action mechanism distinct from that of C5A. The inhibitory effect of GBVA10-9 appeared to occur at the postbinding step during viral entry. Taken together, the results with GBVA10-9 demonstrated a potent activity for blocking HCV entry that might be used in combination with other antivirals directly targeting virus-encoded enzymes. Furthermore, GBVA10-9 also provides a novel tool to dissect the detailed mechanisms of HCV entry.

Traumatic wound microbiome workshop

On May 9-10, 2011, the Walter Reed Army Institute of Research, as the Army Center of Excellence for Infectious Disease, assembled over a dozen leaders in areas related to research into the communities of microorganisms which colonize and infect traumatic wounds. The objectives of the workshop were to obtain guidance for government researchers, to spur research community involvement in the field of traumatic wound research informed by a microbiome perspective, and to spark collaborative efforts serving the Wounded Warriors and similarly wounded civilians. During the discussions, it was made clear that the complexity of these infections will only be met by developing a new art of clinical practice that engages the numerous microbes and their ecology. It requires the support of dedicated laboratories and technologists who advance research methods such as community sequencing, as well as the kinds of data analysis expertise and facilities. These strategies already appear to be bearing fruit in the clinical management of chronic wounds. There are now funding announcements and programs supporting this area of research open to extramural collaborators.

A human claudin-1-derived peptide inhibits hepatitis C virus entry

Hepatitis C virus (HCV) entry is a complicated process that requires multiple host factors, such as CD81, scavenger receptor BI, claudin-1 (CLDN1), and occludin. The interaction of virus and cellular entry factors represents a promising target for novel anti-HCV drug development. In this study, we sought to identify peptide inhibitors for HCV entry by screening a library of overlapping peptides covering the four above-mentioned entry factors. An 18-amino acid peptide (designated as CL58) that was derived from the CLDN1 intracellular and first transmembrane region inhibited both de novo and established HCV infection in vitro. Unlike previously reported peptides corresponding to CLDN1 extracellular loops, CL58 did not alter the normal distribution of CLDN1 and was not cytotoxic in vitro at concentrations nearly 100-fold higher than the effective antiviral dose. The inhibitory effect of CL58 appeared to occur at a late step during viral entry, presumably after initial binding. Finally, overexpressed CL58 was able to interact with HCV envelope proteins.

CONCLUSION

We identified a novel CLDN1-derived peptide that inhibits HCV entry at a postbinding step. The findings expand our knowledge of the roles that CLDN1 play in HCV entry and highlight the potential for developing a new class of inhibitors targeting the viral entry process.

Recombinant human interleukin 28B: anti-HCV potency, receptor usage and restricted cell-type responsiveness

OBJECTIVES

Interleukin 28B (IL28B) genetic variation has been recently reported as a potent predictor of hepatitis C virus (HCV) response to interferon (IFN) therapy. The aim of this study was to produce recombinant human IL28B (rhIL28B) in yeast and explore the action mechanisms of rhIL28B as a novel anti-HCV agent.

METHODS

A simple and efficient protocol for producing rhIL28B in the methylotrophic yeast Pichia pastoris was developed. The anti-HCV activity, induction of IFN-stimulated genes (ISGs), receptor usage and cellular responsiveness of rhIL28B were characterized.

RESULTS

The yield of secreted rhIL28B was optimized to 200 mg/L, and soluble rhIL28B that was approximately 95% pure was achieved using a one-step ion-exchange purification procedure. rhIL28B inhibited HCV propagation in Huh7.5.1 cells with an IC(50) of 0.15 × 10(-3) mg/L. Treatment of hepatoma cells with rhIL28B resulted in the phosphorylation of STAT1 within 1 h and expression of ISGs. The HCV inhibitory effects of rhIL28B were antagonized by the antibody neutralization of receptors IL10R2 and IL28R1. The combination of rhIL28B and ribavirin synergistically inhibited HCV production in cell culture. Importantly, compared with the broad-spectrum activity of IFN-α, we demonstrated restricted cell-type responsiveness of rhIL28B in liver, lung and prostate cells.

CONCLUSIONS

This study established an easy and highly efficient approach for the production of rhIL28B with potent in vitro antiviral activity and restricted cell tropism, and thus provides a novel antiviral candidate for improving the treatment of HCV-infected patients.

Phospholipid scramblase 1 mediates hepatitis C virus entry into host cells

Hepatitis C virus (HCV) infects human hepatocytes through several host factors. However, other prerequisite factors for viral entry remain to be identified. Using a yeast two-hybrid screen, we found that human phospholipid scramblase 1 interacts with HCV envelope proteins E1 and E2. These physical interactions were confirmed by co-immunoprecipitation and GST pull-down assays. Knocking down the expression of PLSCR1 inhibited the entry of HCV pseudoparticles. Moreover, PLSCR1 was required for the initial attachment of HCV onto hepatoma cells, where it specifically interacted with entry factor OCLN. We show that PLSCR1 is a novel attachment factor for HCV entry.

Causes of death among people with convulsive epilepsy in rural West China: a prospective study

BACKGROUND

Epilepsy is a serious health problem associated with an increased risk of premature mortality. Few studies have investigated risk factors for this. Understanding these risks may enable the implementation of preventative measures to reduce premature mortality.

METHODS

A management program for convulsive forms of epilepsy has been in place at the primary health care level in rural West China since May 2005. Demographic data and putative causes of death of attendees of the program since inception to the end of December 2009 have been recorded. Case fatality (CF), the proportional mortality ratios (PMRs) for each cause, and standardized mortality ratios (SMRs) for each age and cause were estimated based on the 2007 Chinese rural population.

RESULTS

There were 106 reported deaths (70 male) among 3,568 people. CF was 2.97% during a median of 28 months' follow-up. The highest PMRs were for accidental death (59%) including drowning (45.1%); probable sudden unexpected death in epilepsy (SUDEP) (14.7%); status epilepticus (6.9%), and neoplasm (6.9%). The overall SMR was 4.92 (95% confidence interval 4.0-6.1); the risks were high in young people. The risk of drowning was 82-fold higher in the cohort than the general population.

CONCLUSION

In rural West China, the risk of premature death is nearly 5 times higher in people with convulsive epilepsy than in the general Chinese population and especially high among young people. Accidental death, including drowning, and probable SUDEP are the leading putative causes of death in people with convulsive epilepsy in rural West China.

Growth differentiation factor 15 is induced by hepatitis C virus infection and regulates hepatocellular carcinoma-related genes

Liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC) are commonly induced by chronic hepatitis C virus (HCV) infection. We aimed to identify and characterize the involvement of previously screened cytokine GDF15 in HCV pathogenesis. We examined the GDF15 expression after HCV infection both in vitro and in vivo. Cultured JFH-1 HCV was used to determine the GDF15 function on virus propagation. GDF15 overexpression and RNA interference were employed to profile the GDF15-regulated genes, signaling pathways and cell biology phenotypes. The mRNA expression and protein secretion of GDF15 was dramatically increased in HCV-infected hepatoma cells, which maybe a host response to viral proteins or infection-induced cell stress. Patients infected with HCV had an average 15-fold higher blood GDF15 level than that of healthy volunteers. Three HCC individuals in the HCV cohort showed extremely high GDF15 concentrations. Transfection or exogenously supplied GDF15 enhanced HCV propagation, whereas knockdown of endogenous GDF15 resulted in inhibition of virus replication. Overexpressed GDF15 led to Akt activation and the phosphorylation of Akt downstream targeted GSK-3β and Raf. Several HCC-related molecules, such as E-cadherin, β-catenin, Cyclin A2/B1/D1, were up-regulated by GDF15 stimulation in vitro. Overexpression of GDF15 in hepatoma cells resulted in increased DNA synthesis, promoted cell proliferation, and importantly enhanced invasiveness of the cells. In conclusion, these results suggest that an elevated serum GDF15 level is a potential diagnostic marker for viral hepatitis, and GDF15 may contribute to HCV pathogenesis by altering the signaling and growth of host cells.