Cytokine profile and cytoskeletal changes after herpes simplex virus type 1 infection in human trabecular meshwork cells.

Uveitis caused by herpes simplex virus (HSV)-1 is characterized by increased intraocular pressure (IOP) in the presence of anterior chamber inflammation. Despite their clinical significance, the pathogenic changes associated with HSV-1 infection in trabecular meshwork (TM) cells, the key cell type regulating IOP, have not been completely elucidated. In this study, cytokine array analyses showed a significant stepwise increase in monocyte chemoattractant protein (MCP)-1 expression upon HSV-1 infection in TM cells (p < 0.05). HSV-1 infection led to downregulation of fibrogenic molecules (fibronectin, α-smooth muscle actin, connective tissue growth factor and TGF-ß1). Notably, HSV-1 infection caused a significant increase in actin stress fibres, with a twofold increase in active RhoA, which was enhanced by treatment with TGF-ß1 and inhibited by treatment with the Rho-kinase inhibitor, Y-27632. TM cells treated with MCP-1 exhibited a dose-dependent increase in actin stress fibres compared to untreated TM cells. Our study suggests that HSV-1 infection in TM cells increases cell contractile activity rather than fibrotic changes in the extracellular matrix (ECM) components. Taken together, these observations demonstrate the enhanced expression of MCP-1 and TM cell contractile activity upon HSV-1 infection and events with potential implications for the pathobiology of abrupt IOP elevation in HSV-1 anterior uveitis.

DNA looping-dependent autorepression of LEE1 P1 promoters by Ler in enteropathogenic Escherichia coli (EPEC).

Ler, a homolog of H-NS in enteropathogenic Escherichia coli (EPEC), plays a critical role in the expression of virulence genes encoded by the pathogenic island, locus of enterocyte effacement (LEE). Although Ler acts as an antisilencer of multiple LEE operons by alleviating H-NS-mediated silencing, it represses its own expression from two LEE1 P1 promoters, P1A and P1B, that are separated by 10 bp. Various in vitro biochemical methods were used in this study to elucidate the mechanism underlying transcription repression by Ler. Ler acts through two AATT motifs, centered at position -111.5 on the coding strand and at +65.5 on the noncoding strand, by simultaneously repressing P1A and P1B through DNA-looping. DNA-looping was visualized using atomic force microscopy. It is intriguing that an antisilencing protein represses transcription, not by steric exclusion of RNA polymerase, but by DNA-looping. We propose that the DNA-looping prevents further processing of open promoter complex (RPO) at these promoters during transcription initiation.

Full genomic analysis of a human rotavirus G1P[8] strain isolated in South Korea.

A rotavirus G1P[8] strain C1-81 was isolated from a 5-month-old female infant admitted to hospital with fever and severe diarrhea in Incheon, South Korea. To investigate its full genomic relatedness and its group, the full genome of strain C1-81 was determined. Based on a full genome classification system, C1-81 was shown to possess the typical Wa-like genotype constellation: G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. On the basis of sequence similarities, the strain was shown to be the closest related strain to contemporary human rotavirus strains with recent strains isolated in Asia. This C1-81 strain showed the highest degree of nucleic acid similarity (98.8% and 97%) to G1 B4633-03 and P[8] (Thai-1604 and Dhaka8-02), respectively. This is the first report that group A rotavirus was analyzed with G1P[8] in South Korea. The study of the complete genome of the virus will help understanding of the evolution of rotavirus.

Increased Complement-Associated Inflammation in Cytomegalovirus-Positive Hypertensive Anterior Uveitis Patients Based on the Aqueous Humor Proteomics Analysis.

Herpetic anterior uveitis-associated ocular inflammation is commonly manifested with ocular hypertension and glaucoma. Relative to other viruses, cytomegalovirus (CMV) positive hypertensive anterior uveitis is associated with high recurrences of uveitis, as well as with uncontrolled intraocular pressure (IOP) and a subsequent higher requirement for future glaucoma surgery. To gain novel insights into the pathogenesis of ocular hypertension in these patients, we investigated the proteome changes of the aqueous humor (AH) derived from the CMV hypertensive anterior uveitis (CMV-HAU; n = 10) patients and non-glaucoma (cataract; n = 10) patients using liquid chromatography with tandem mass spectrometry. Among a total of 562 proteins identified, fifty and fifteen proteins were significantly elevated and decreased, respectively, in the AH of CMV-HAU patients compared to the control subjects by ≥2 fold. Gene ontology (GO) enrichment and network analyses of elevated proteins revealed that the enrichment of protein was involved in the complement activation, the humoral immune response mediated by the circulating immunoglobulins, proteolysis, and platelet degranulation. In the AH of CMV-HAU, GDF (growth/differentiation factor)-15, the inflammatory marker belonging to the TGF-ß superfamily proteins, was significantly increased, while vasorin, an anti-TGF-ß protein, levels were decreased. The trabecular meshwork cells infected with CMV exhibited a significantly increased expression of inflammatory markers. Collectively, these data indicate increased complement factor associated inflammation and humoral immunity in CMV-HAU associated ocular hypertension.

Nationwide groundwater surveillance of noroviruses in South Korea, 2008.

To inspect the norovirus contamination of groundwater in South Korea, a nationwide study was performed in the summer (June to August) and winter (October to December) of 2008. Three-hundred sites designated by the government ministry were inspected. Water samples were collected for analysis of water quality, microorganism content, and viral content. Water quality was assessed by temperature, pH, turbidity, residual chlorine, and nitrite nitrogen content. Microorganism contents were analyzed bacteria, total coliforms, Escherichia coli, and bacteriophage. Virus analyses included panenterovirus and norovirus. Two primer sets were used for the detection of norovirus genotypes GI and GII, respectively. Of 300 samples, 65 (21.7%) were norovirus positive in the summer and in 52 (17.3%) were norovirus positive in the winter. The genogroup GI noroviruses that were identified were GI-1, GI-2, GI-3, GI-4, GI-5, GI-6, and GI-8 genotypes; those in the GII genogroup were GII-4 and GII-Yuri genotypes. The analytic data showed correlative relationships between the norovirus detection rate and the following parameters: water temperature and turbidity in physical-chemical parameters and somatic phage in microbial parameters. It is necessary to periodically monitor waterborne viruses that frequently cause epidemic food poisoning in South Korea for better public health and sanitary conditions.

Standardized positive controls for detection of norovirus by reverse transcription PCR.

BACKGROUND: Norovirus is one of the most common causes of nonbacterial gastroenteritis in humans. Rapid spread by contaminated food and person-to-person transmission through the fecal-oral route are characteristics of norovirus epidemiology and result in high morbidity in vulnerable patient populations. Therefore, detection of norovirus is a major public health concern. Currently, the most common method for detecting and differentiating among norovirus strains in clinical and environmental samples is reverse transcription PCR (RT-PCR). Standardized positive controls used in RT-PCR assays to detect norovirus are designed to overcome the problem of false-negative results due to PCR inhibitors and suboptimal reaction conditions. RESULTS: In the current study, four types of RNA transcripts were produced from plasmids: norovirus GI-5 and GII-4 capsid regions with human rotavirus (VP7 gene derived) fragment insertions, and norovirus GI-6 and GII-4 capsid regions with hepatitis A virus (VP1/P2A gene derived) fragment insertions. These size-distinguishable products were used as positive controls under the RT-PCR assay conditions used to detect NoV in stool and groundwater samples. Their reliability and reproducibility was confirmed by multiple sets of experiments. CONCLUSIONS: These standardized products may contribute to the reliable and accurate diagnosis by RT-PCR of norovirus outbreaks, when conducted by laboratories located in different regions.

Full sequence analysis and characterization of the South Korean Norovirus GII-4 variant CUK-3.

BACKGROUND: Many of researchers have focused on the emerging pathogen, Norovirus, since its first identification as the causing agent of nonbacterial acute gastroenteritis in humans. One of the virulence factors of norovirus, the great genetic diversity attributed to point mutations and recombinations, has brought forth the result of significant changes in the circulating norovirus genotype patterns. FINDINGS: In recognition of the necessity for tracking and monitoring of genetic diversity, a norovirus variant among the most prevalent genotype GII-4, Norovirus Hu/GII-4/CUK-3/2008/KR (CUK-3), was isolated from stool samples and analyzed on the level of whole genome sequence. Whole genome sequence analysis revealed three ORF composites of the whole genome, ORF1 (5100 bp), ORF2 (1623 bp), and ORF3 (807 bp). Each genetic relationship of CUK-3 variant analysis located the ORF1 (5,100 bp) in Cluster I, ORF2 (1623 bp) in Cluster I (2006b), ORF3 (807 bp) in Cluster I, and the whole genome sequence (about 5.1 kb) in Cluster I in the phylogenetic tree. And the phylogenetic analyses showed the same location of CUK-3 strain with the GII-4/2006b cluster in the phylogenetic tree. CONCLUSIONS: In This study, a first concerning the full-length sequence of a NoV variant in South Korea is meaningful in that it can be used not only as a full-length NoV variant sequence standard for future comparison studies, but also as useful material for the public health field by enabling the diagnosis, vaccine development, and prediction of new emerging variants.

Evaluation of electropositive filtration for recovering norovirus in water.

The virus adsorption-elution (VIRADEL) technique has been widely used in the recovery of various enteric viruses in water, and an electropositive filter such as 1 MDS has been commonly applied. However, effective methods of monitoring waterborne norovirus (NoV) have not yet been well characterized and optimized. Hence, in this study, the VIRADEL technique was evaluated and optimized for effectively detecting NoV in water by two commonly used electropositive filters (1MDS and NanoCeram filter). Various elution and concentration methods were evaluated by using both murine norovirus (MNV) and human NoV. Among the tested elution buffers, the most effective was 1.5% beef extract plus 0.01% Tween 80 for both 1MDS (67.5%) and NanoCeram (85.7%) microfilters. The recovery rate of GII-4 human NoV was higher by organic flocculation (86.6%) than by polyethylene glycol (PEG) precipitations (11.6~73.6%). When both 1MDS and NanoCeram filters were tested to detect NoV in surface and groundwater, the sensitivity of NoV recovered by these filters appeared to depend on the types and conditions of environmental water. The results of this study will help to set a standard of detection method for NoV in water.

Role of MCP-1 and IL-8 in viral anterior uveitis, and contractility and fibrogenic activity of trabecular meshwork cells.

The inflammatory chemokines, monocyte chemoattractant protein (MCP)-1 and IL-8, are produced by normal trabecular meshwork cells (TM) and elevated in the aqueous humor of primary open angle glaucoma (POAG) and hypertensive anterior uveitis associated with viral infection. However, their role in TM cells and aqueous humor outflow remains unclear. Here, we explored the possible involvement of MCP-1 and IL-8 in the physiology of TM cells in the context of aqueous outflow, and the viral anterior uveitis. We found that the stimulation of human TM cells with MCP-1 and IL-8 induced significant increase in the formation of actin stress fibers and focal adhesions, myosin light chain phosphorylation, and the contraction of TM cells. MCP-1 and IL-8 also demonstrated elevation of extracellular matrix proteins, and the migration of TM cells. When TM cells were infected with HSV-1 and CMV virus, there was a significant increase in cytoskeletal contraction and Rho-GTPase activation. Viral infection of TM cells revealed significantly increased expression of MCP-1 and IL-8. Taken together, these results indicate that MCP-1 and IL-8 induce TM cell contractibility, fibrogenic activity, and plasticity, which are presumed to increase resistance to aqueous outflow in viral anterior uveitis and POAG.

Determining the efficacy of 27 commercially available disinfectants against human noroviruses.

BACKGROUND: Recently, monoclonal-antibody-conjugated immunomagnetic separation (IMS) procedure combined with quantitative reverse transcription-polymerase chain reaction (qRT-PCR) has been used for quantifying non-cultivated human noroviruses (HuNoVs). METHODS: We examined the efficacy of 27 commercially available disinfectants and a prototype against GII.4 strain HuNoV through the IMS/qRT-PCR assay. RESULTS: The average log reduction in viral titer in vitro varied among the disinfectants. The prototype was the most effective with an average log reduction of 6.86 log. CONCLUSIONS: The IMS/RT-qPCR assay is an effective method to evaluate the activities of disinfectants against GII.4 HuNoV in vitro. Further work is needed to enhance the virucidal activity of the prototype disinfectant against more resistant HuNoV strains.

Detection of replicating negative-sense RNAs in CaCo-2 cells infected with human astrovirus.

Human astrovirus (HAstV) is the second most important cause of viral diarrhea and acute gastroenteritis in infants under five. However, determination of the infectivity of clinical isolates is difficult, and the replication cycle of HAstV is not yet fully understood. In this study, it was attempted to detect negative-sense (-)RNAs generated during the replication of RNA viruses. We used clinical isolates of HAstV to infect CaCo-2 cells. Reverse transcription using only a sense primer followed by PCR using both sense and antisense primers showed that (-)RNAs were first detected in CaCo-2 cells between 9 and 12 h postinfection (p.i.). However, these (-)RNAs were not detected when cells were treated with the protein synthesis inhibitor cycloheximide during HAstV infection. Next, RT with only an antisense primer followed by PCR was performed to detect (+)RNA of HAstVs after production of (-)RNAs during replication. RT-PCR results using the antisense primer revealed that the amount of (+)RNA began to increase starting 9 h p.i., indicating an accumulation of the newly synthesized (+)RNA genome. Cycloheximide was observed to abrogate the increase of newly made (+)RNA during HAstV infection. In conclusion, the use of sense or antisense primers during the RT reaction together with cycloheximide enabled us to quantitatively detect (-)RNAs, and this proved to be an useful tool in understanding the replication cycle of HAstV.

Development of a real-time loop-mediated isothermal amplification method for the detection of severe fever with thrombocytopenia syndrome virus.

Severe fever with thrombocytopenia syndrome (SFTS) is being reported annually in South Korea since its first detection there in 2010. The causal agent is a negative-strand RNA virus 80-100 nm in diameter. It causes fever, thrombocytopenia, leukocytopenia, gastrointestinal symptoms, and neural symptoms. The mortality rate of SFTS was 32.6% among 172 cases reported from 2012 to 2015 in South Korea. Thus, is necessary to develop an effective diagnostic method that selectively identifies the isolates circulating in South Korea. The real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay is a simple, rapid, and sensitive approach for molecular diagnosis. Here, we designed novel primers for this assay and found that the technique had very high specificity, sensitivity, and efficiency. This real-time RT-LAMP approach using the novel primers developed herein can be applied for early diagnosis of SFTSV strains in South Korea to reduce the mortality rate of SFTS.

Sequence analysis of the first B5 subgenogroup strain of enterovirus 71 isolated in Korea.

Enterovirus A71 (EV71), the main etiological agent of handfoot- mouth disease (HFMD), circulates in many areas of the world and has caused large epidemics since 1997, especially in the Asia-Pacific region. In this study, we determined the full-genome sequence of CMC718, a newly isolated EV71 strain in Korea. The CMC718 genome was 7,415 nucleotides in length and was confirmed by whole-genome phylogenetic analysis to belong to the B5 genotype. In particular, CMC718 demonstrated maximum identity with strain M988 of the B5 genotype and numerous amino acid variants were detected in the 3D domain of the viral protein P3, which is consistent with the mutation pattern of a B5 strain isolated in 2012-2013. Comparison of the CMC718 sequence with other EV71 reference strains confirmed the relationship and genetic variation of CMC718. Our study was a full-genome sequence analysis of the first EV71 strain of the B5 genotype isolated in South Korea. This information will be a valuable reference for the development of methods for the detection of recombinant viruses, the tracking of infections, and the diagnosis of EV71.

Correction: The effects of losartan on cytomegalovirus infection in human trabecular meshwork cells.

[This corrects the article DOI: 10.1371/journal.pone.0218471.].

Molecular genomic characterization of severe fever with thrombocytopenia syndrome virus isolates from South Korea.

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne emerging infectious disease caused by the SFTS virus (SFTSV) and is a threat to public health due to its high fatality rate. However, details on tick-to-human transmission of SFTSV are limited. In this study, we determined the whole-genome sequence of a South Korean SFTSV strain (CUK-JJ01), compared it to those of other recent human SFTSV isolates, and identified the genetic variations and relationships among the SFTSV strains. The genome of CUK-JJ01 was consistent with the genome of other members of the genus Phlebovirus, including the large (L), medium (M), and small (S) segments of 6368, 3378, and 1744 nucleotides, respectively. Based on amino acid sequences of the M and S segments, which are used to distinguish the six SFTSV genotypes, CUK-JJ01 was classified as genotype B. Segment analysis revealed that the L, M, and S segments were 97.49%, 97.18%, and 97.94% similar to those of KAJNH2/2013/Korea, ZJZHSH-FDE/2012/China, and KADGH/2013/Korea, respectively. Currently, only few studies on SFTSV have been conducted in Korean population and most were limited to serological analysis. Although the present study has limitations in terms of number of sample analyzed, the findings may serve as basis to understand the transmission and spread of SFTSV, as well as for the development of diagnostic and detection methods for viral recombinants by comparing the whole genome sequence of SFTSV isolates from South Korea and that of foreign isolates.

The effects of losartan on cytomegalovirus infection in human trabecular meshwork cells.

BACKGROUND: Human cytomegalovirus (CMV) has been emerged as one of the causes of acute recurrent or chronic hypertensive anterior uveitis in immunocompetent. In hypertensive anterior uveitis, human trabecular meshwork (TM) cells are considered a focus of inflammation. We investigated the effects of losartan, a selective angiotensin II receptor antagonist, on CMV infection in human TM cells. METHODS: Human TM cells were infected with CMV AD169. Virus infected and mock-infected cells were treated with losartan or dexamethasone or ganciclovir with or without transforming growth factor (TGF)-ß1. Viral DNA accumulation and host cell response were analyzed using real-time PCR. Levels of secreted TGF-ß1 were measured by determining its concentration in conditioned medium using a commercially available sandwich enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: CMV infection significantly increased the concentrations of the secreted TGF-ß1 at 3, 5, and 7 day post infection in TM cells. Treatment with dexamethasone or losartan significantly decreased the levels of TGF-ß1, whereas treatment with ganciclovir did not affect TGF-ß1 levels. TM cells treated with TGF-ß1 along with the presence of losartan for 48 hours showed marked decrease in the expression of α-smooth muscle actin (SMA), lysyl oxidase (LOX), connective tissue growth factor (CTGF), fibronectin and collagen-1A, compared with cells treated with TGF-ß1 alone. CMV-infected TM cells stimulated by TGF-ß1 significantly increased the expression of α-SMA and CTGF, which were attenuated by additional treatment with losartan. CONCLUSION: Losartan inhibited the expression of TGF-ß1 and fibrogenic molecules in human TM cells. Thus, losartan has the potential to decrease TM fibrosis in patients with CMV-induced hypertensive anterior uveitis.

Transcriptional changes after herpes simplex virus type 1 infection in human trabecular meshwork cells.

BACKGROUND: Herpes simplex virus type 1 (HSV-1) is causative for hypertensive anterior uveitis. Trabecular meshwork (TM) cells, which are the key cells regulating intraocular pressure (IOP), is considered to be the site of inflammation. We explored the profiles of genes expressed in human TM primary cells upon HSV-1 infection. METHODS: Human TM cells were infected with HSV-1 and total RNA was isolated. The global transcriptional gene network analyses were performed in mock-infected and HSV-1 infected TM cells. Using ingenuity pathway analysis, we determined the key biological networks upon HSV-1 infection. The results of microarray analyses were validated using quantitative PCR. RESULTS: TM cells had a high susceptibility to HSV-1 infection. HSV-1 induced transcriptional suppression of many components related to fibrosis in TM cells. The top biological network related to the genes which were significantly altered upon HSV-1 infection was organismal injury and abnormalities involving TGF-ß1 and PDGF-BB. The results of PCR analyses for selected molecules were found to be in good agreement with the microarray data. HSV-1-infected TM cells showed an 80-fold increase in the expression of PDGF-BB, which was further increased by treatment with TGF-ß1. HSV-1 also induced a 4-fold increase in the expression of the monocyte chemoattractant protein (MCP)-1, the downstream molecules of PDGF-BB. CONCLUSIONS: In human TM cells, HSV-1 induced transcriptional suppression of many components related to fibrosis and enhanced expression of both PDGF-BB and MCP-1. Our study may provide a novel mechanism for the pathogenesis of HSV-1 infection in TM cells.

Molecular epidemiology of norovirus infections in children with acute gastroenteritis in South Korea in November 2005 through November 2006.

Norovirus infections were detected in 114 of 762 children with acute gastroenteritis in South Korea from November 2005 to November 2006. Seasonality peaks in December, March, and October were also assessed in this study. We identified seven noroviral genotypes (GI-6, GII-2, GII-3, GII-4, GII-5, GII-6, and GII-8) and a C1-120 strain showing low identity (79.3%) with GII-13 and GII-17.

Cell growth inhibition and down-regulation of survivin by silibinin in a laryngeal squamous cell carcinoma cell line.

OBJECTIVES: Abnormalities in the regulation of apoptotic cell death have been shown to have an important effect on the pathogenesis and progression of cancer. Survivin, which is identified in most cancers and has recently been identified as an inhibitor of apoptosis, is a potential therapeutic target for cancer management. We investigated cell growth, apoptosis, and expression of survivin in laryngeal squamous cell carcinoma cell lines after treatment with the bioactive compound silibinin. METHODS: Cultured human laryngeal squamous cell carcinoma SNU-46 cells were treated with different concentrations of silibinin, and the degree of cell growth and apoptosis was analyzed. Additionally, survivin protein and messenger RNA were analyzed by Western immunoblotting and reverse transcription-polymerase chain reaction. RESULTS: Silibinin inhibited the growth of SNU-46 cells in a both dose- and time-dependent manner (p < 0.01). Upon fluorescence-activated cell sorter analysis, silibinin (200 micromol/L) treatment increased the proportion of apoptotic cells from 7% to 40%. At high concentrations (more than 150 micromol/L), silibinin greatly reduced messenger RNA and protein expression of survivin. CONCLUSIONS: Our findings demonstrate that silibinin induced apoptosis of laryngeal squamous carcinoma cells by a mechanism involving decreased survivin expression, which suggests the possibility that silibinin may be an effective treatment of laryngeal cancers.

Direct vaccination with pseudotype baculovirus expressing murine telomerase induces anti-tumor immunity comparable with RNA-electroporated dendritic cells in a murine glioma model.

Baculovirus pseudotyped with vesicular stomatitis virus G protein (Bac-VSV-G) was found to efficiently transduce and express transgenes on mammalian cells. In this study, this recombinant virus was used for induction of anti-tumor immunity against murine telomerase reverse transcriptase (mTERT) and was compared with RNA-electroporated dendritic cells (DCs) in a murine glioma model. Splenocytes from the mice vaccinated with Bac-VSV-G expressing mTERT (Bac-VSVG-mTERT) showed significantly increased numbers of mTERT-specific IFN-gamma-secreting T cells using an ELISPOT technique, and also showed increased NK cell activity. In addition, the TERT-specific T cells activated by Bac-VSVG-mTERT and mTERT RNA-electroporated DCs were predominantly CD4+ T cells and CD8+ T cells, respectively. The protective anti-tumor effect of Bac-VSVG-mTERT was similar to that of mTERT RNA-electroporated DCs. These results suggest that the pseudotype baculovirus expressing TERT may be a good candidate for a genetic vaccine for use in the treatment of malignant gliomas.