Phytochemical Screening and Protective Effects of Prunus persica Seeds Extract on Carbon Tetrachloride-Induced Hepatic Injury in Rats.

BACKGROUND AND PURPOSE: Carbon tetrachloride (CCl4) is a dynamic environmental toxin released from chemical factories and its concentration in the atmosphere is accelerating at an alarming proportion. The potential presence of CCl4 in the human body causes liver injury via free radical stimulated inflammatory responses. OBJECTIVES: In this study, protective effects of hydromethanolic seeds extract of Prunus persica (PPHM) were evaluated for free radical scavenging potential in CCl4 mediated acute liver toxicity in the murine model. EXPERIMENTAL APPROACH: Followed by acute oral toxicity analysis, liver cells of Sprague-Dawley (SD) rats were treated with CCl4 and subsequently, the chemoprophylactic effect of extract (400 mg/Kg dose) was evaluated using in vivo studies including, silymarin as the positive control. Biochemical parameters, staining (hematoxylin and eosin (H & E) and Masson's Trichome) and quantitative gene expression analysis via real-time PCR were used to evaluate hepatic damage control. RESULTS: The results illustrated that PPHM extract exhibit strong anti-oxidant activity, comparable to the positive control, gallic acid. Research study results also demonstrated that the extract treatment at 400 mg/Kg concentration is highly effective in protecting liver damage due to CCl4 exposure. Mechanistic investigations indicated that the therapeutic action of PPHM was correlated with the increase in Nrf2, NQO-1 and decrease in collagen III mRNA genes expression compared to CCl4 treated group. CONCLUSIONS AND IMPLICATIONS: Accordingly, our research study indicated that PPHM alleviated CCl4-mediated oxidative stress through Nrf2/NQO-1 pathway, thereby protecting liver damage against environmental toxins. Our findings provide supportive evidence to suggest PPHM as a novel nontoxic hepatoprotective agent.

Blood-based gene expression profile of oxidative stress and antioxidant genes for identifying surrogate markers of liver tissue injury in chronic hepatitis C patients.

Oxidative stress is the process by which reactive molecules and free radicals are formed in cells. In this study, we report the blood-based gene expression profile of oxidative stress and antioxidant genes for identifying surrogate markers of liver tissue in chronic hepatitis C (CHC) patients by using real-time PCR. A total of 144 untreated patients diagnosed with CHC having genotype 3a and 20 healthy controls were selected for the present study. Liver biopsy staging and grading of CHC patients were performed using the METAVIR score. Total RNA was extracted from liver tissue and blood samples, followed by cDNA synthesis and real-time PCR. The relative expression of genes was calculated using the ΔΔCt method. The expression profile of 84 genes associated with oxidative stress and antioxidants was determined in liver tissue and blood samples. In liver tissue, 46 differentially expressed genes (upregulated, 27; downregulated, 19) were identified in CHC patients compared to normal samples. In blood, 61 genes (upregulated, 51; downregulated; 10) were significantly expressed in CHC patients. A comparison of gene expression in liver and whole blood showed that 20 genes were expressed in a similar manner in the liver and blood. The expression levels of commonly expressed liver and blood-based genes were also correlated with clinical factors in CHC patients. A receiver operating curve (ROC) analysis of oxidative stress genes (ALB, CAT, DHCR24, GPX7, PRDX5, and MBL2) showed that infections in patients with CHC can be distinguished from healthy controls. In conclusion, blood-based gene expression can reflect the behavior of oxidative stress genes in liver tissue, and this blood-based gene expression study in CHC patients explores new blood-based non-invasive biomarkers that represent liver damage.

Threats of Zika virus transmission for Asia and its Hindu-Kush Himalayan region.

Asia and its Hindu Kush Himalayan (HKH) region is particularly vulnerable to environmental change, especially climate and land use changes further influenced by rapid population growth, high level of poverty and unsustainable development. Asia has been a hotspot of dengue fever and chikungunya mainly due to its dense human population, unplanned urbanization and poverty. In an urban cycle, dengue virus (DENV) and chikungunya virus (CHIKV) are transmitted by Aedes aegypti and Ae. albopictus mosquitoes which are also competent vectors of Zika virus (ZIKV). Over the last decade, DENV and CHIKV transmissions by Ae. aegypti have extended to the Himalayan countries of Bhutan and Nepal and ZIKV could follow in the footsteps of these viruses in the HKH region. The already established distribution of human-biting Aedes mosquito vectors and a naïve population with lack of immunity against ZIKV places the HKH region at a higher risk of ZIKV. Some of the countries in the HKH region have already reported ZIKV cases. We have documented an increasing threat of ZIKV in Asia and its HKH region because of the high abundance and wide distribution of human-biting mosquito vectors, climate change, poverty, report of indigenous cases in the region, increasing numbers of imported cases and a naïve population with lack of immunity against ZIKV. An outbreak anywhere is potentially a threat everywhere. Therefore, in order to ensure international health security, all efforts to prevent, detect, and respond to ZIKV ought to be intensified now in Asia and its HKH region. To prepare for possible ZIKV outbreaks, Asia and the HKH region can also learn from the success stories and strategies adopted by other regions and countries in preventing ZIKV and associated complications. The future control strategies for DENV, CHIKV and ZIKV should be considered in tandem with the threat to human well-being that is posed by other emerging and re-emerging vector-borne and zoonotic diseases, and by the continuing urgent need to strengthen public primary healthcare systems in the region.

TNF-α Genetic Predisposition and Higher Expression of Inflammatory Pathway Components in Keratoconus.

Purpose: To date keratoconus (KC) pathogenesis is undefined; however, the involvement of inflammatory pathways in disease development is becoming apparent. In the present study, we investigated the role of a promoter region polymorphism rs1800629 (-308G>A) in the inflammatory pathway component TNF-α and its effects on the expression of TNF-α and downstream molecules tumor necrosis factor receptor 1 and 2 (TNFR1 and TNFR2), v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA), and interleukin 6 (IL-6) in KC development. Methods: TNF-α promoter polymorphism rs1800629 (-308G>A), was genotyped in 257 sporadic KC patients and 253 healthy controls. Enzyme-linked immunosorbent assay (ELISA) was performed to assess for the -308G>A genotypes. Quantitative polymerase chain reaction (qPCR) was carried out to compare the mRNA expression of TNF-α, TNFR1, TNFR2, RELA, and IL6 in the corneal tissues of 20 KC patients and 20 donor controls. Results: The -308G>A genotype GA was found to be significantly associated with KC development (dominant model [odds ratio (OR) = 6.67 (95% confidence interval [CI] = 4.28-10.42), P < 0.001]) and allele-A (OR = 4.30, 95%CI = 2.93-6.34, P < 0.001). TNF-α serum levels were significantly raised in patients with GA genotype (196.5 ± 69.5 pg/mL) compared to reference genotype GG (21.7 ± 8.2 pg/mL) (P < 0.0001). There was a significant overexpression of TNF-α (P = 0.002), TNFR2 (P = 0.0001), RELA (P = 0.0117), and IL6 (P = 0.0007) in the KC corneal tissues as compared to the control. Conclusions: The GA genotype of the TNF-α -308G>A polymorphism is a significant genetic risk factor for the pathogenesis of KC. Moreover, this single nucleotide polymorphism (SNP) was observed to be associated with deregulated expression of downstream molecules, thus further reinforcing the role of the inflammatory pathway components in the development of KC.

Evolution of codon usage in Zika virus genomes is host and vector specific.

The codon usage patterns of viruses reflect the evolutionary changes that allow them to optimize their survival and adapt their fitness to the external environment and, most importantly, their hosts. Here we report the genotype-specific codon usage patterns of Zika virus (ZIKV) strains from the current and previous outbreaks. Several genotype-specific and common codon usage traits were noted in the ZIKV coding sequences, indicating their independent evolutionary origins from a common ancestor. The overall influence of natural selection was more profound than that of mutation pressure, acting on a specific set of viral genes in the Asian-genotype ZIKV strains from the recent outbreak. An interplay between codon adaptation and deoptimization may have allowed the virus to adapt to multiple host and vectors and is reported for the first time in ZIKV genomes. Combining our codon analysis with geographical data on Aedes populations in the Americas suggested that ZIKV has evolved host- and vector-specific codon usage patterns to maintain successful replication and transmission chains within multiple hosts and vectors.

Parallel expression profiling of hepatic and serum microRNA-122 associated with clinical features and treatment responses in chronic hepatitis C patients.

MicroRNAs (miRNAs) are small, non-coding RNAs that regulate a variety of biological processes. Recently, human liver-specific miRNA miR-122 has been reported to facilitate hepatitis C virus (HCV) replication in liver cells. HCV is one of the leading causes of liver diseases worldwide. In Pakistan, the estimated prevalence is up to 10%. Here, we report hepatic and serum miR-122 expression profiling from paired liver and serum samples from treatment-naive chronic hepatitis C (CHC) patients and controls. We aimed to elucidate the biomarker potential of serum miR-122 for monitoring disease progression and predicting end treatment response (ETR). Hepatic miR-122 levels were significantly down-regulated in CHC patients. A significant inverse correlation was observed between hepatic and serum miR-122 levels, indicating that serum miR-122 levels reflect HCV-associated disease progression. Both hepatic and serum miR-122 were significantly correlated (P < 0.05) with several clinicopathological features of CHC. Receiver operator curve analysis showed that serum miR-122 had superior discriminatory ability even in patients with normal alanine transaminase levels. Multivariate logistic regression analysis highlighted pre-treatment serum miR-122 levels as independent predictors of ETR. In conclusion, serum miR-122 holds the potential to serve as a promising biomarker of disease progression and ETR in CHC patients.

Expression profiling of serum microRNA-101 in HBV-associated chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma.

MicroRNAs (miRNAs) represent a class of evolutionarily conserved, non-coding small RNAs (18-25 nt) that have emerged as master regulators of several biological processes. Recently, circulating miRNAs have also been reported to be promising biomarkers for various pathological conditions. In the present study, we report the comparative expression profiling of microRNA-101 (miR-101) in serum and tissue samples from chronic hepatitis B (CHB), HBV-associated liver cirrhosis (HBV-LC), and HBV-associated hepatocellular carcinoma (HBV-HCC) patients and healthy controls. The serum miR-101 levels were found to be significantly downregulated in the HBV-HCC patients compared with the HBV-LC patients (P<0.001), CHB patients (P<0.001) and healthy controls but were upregulated in the HBV-LC patients compared with the CHB patients (P<0.001) and healthy controls (P<0.001). Consistent with the serum data, the expression of miR-101 was also upregulated and downregulated in the HBV-LC and HBV-HCC tissue samples, respectively. A receiver operating characteristic (ROC) analysis of serum miR-101 yielded an area under the ROC curve (AUC) of 0.976 with 95.5% sensitivity and 90.2% specificity when differentiating between HBV-HCC and HBV-LC. Our results suggest that the serum miR-101 level can serve as a potential non-invasive biomarker to differentiate HBV-HCC from HBV-LC.

Construction of a chimeric secretory IgA and its neutralization activity against avian influenza virus H5N1.

Secretory immunoglobulin A (SIgA) acts as the first line of defense against respiratory pathogens. In this assay, the variable regions of heavy chain (VH) and Light chain (VL) genes from a mouse monoclonal antibody against H5N1 were cloned and fused with human IgA constant regions. The full-length chimeric light and heavy chains were inserted into a eukaryotic expressing vector and then transfected into CHO/dhfr-cells. The chimeric monomeric IgA antibody expression was confirmed by using ELISA, SDS-PAGE, and Western blot. In order to obtain a dimeric secretory IgA, another two expressing plasmids, namely, pcDNA4/His A-IgJ and pcDNA4/His A-SC, were cotransfected into the CHO/dhfr-cells. The expression of dimeric SIgA was confirmed by using ELISA assay and native gel electrophoresis. In microneutralization assay on 96-well immunoplate, the chimeric SIgA showed neutralization activity against H5N1 virus on MDCK cells and the titer was determined to be 1 : 64. On preadministrating intranasally, the chimeric SIgA could prevent mice from lethal attack by using A/Vietnam/1194/04 H5N1 with a survival rate of 80%. So we concluded that the constructed recombinant chimeric SIgA has a neutralization capability targeting avian influenza virus H5N1 infection in vitro and in vivo.

Genome-wide analysis of codon usage and influencing factors in chikungunya viruses.

Chikungunya virus (CHIKV) is an arthropod-borne virus of the family Togaviridae that is transmitted to humans by Aedes spp. mosquitoes. Its genome comprises a 12 kb single-strand positive-sense RNA. In the present study, we report the patterns of synonymous codon usage in 141 CHIKV genomes by calculating several codon usage indices and applying multivariate statistical methods. Relative synonymous codon usage (RSCU) analysis showed that the preferred synonymous codons were G/C and A-ended. A comparative analysis of RSCU between CHIKV and its hosts showed that codon usage patterns of CHIKV are a mixture of coincidence and antagonism. Similarity index analysis showed that the overall codon usage patterns of CHIKV have been strongly influenced by Pan troglodytes and Aedes albopictus during evolution. The overall codon usage bias was low in CHIKV genomes, as inferred from the analysis of effective number of codons (ENC) and codon adaptation index (CAI). Our data suggested that although mutation pressure dominates codon usage in CHIKV, patterns of codon usage in CHIKV are also under the influence of natural selection from its hosts and geography. To the best of our knowledge, this is first report describing codon usage analysis in CHIKV genomes. The findings from this study are expected to increase our understanding of factors involved in viral evolution, and fitness towards hosts and the environment.

Genomic analysis of HAdV-B14 isolate from the outbreak of febrile respiratory infection in China.

Human adenovirus type 14 (HAdV-B14) was first reported in 1955 from the Netherlands and since then had been associated with outbreaks of febrile respiratory illness (FRI). In China, sporadic HAdV-B14 infections were first identified in 2010, in Guangzhou and Beijing. In 2012, an outbreak of FRI occurred in Beijing and the etiological agent was determined to be HAdV-B14. We present a complete HAdV-B14 genome sequence isolated from this recent FRI outbreak. Virus in 30 throat swab samples was detected using polymerase chain reaction assays, and confirmed by sequencing of the fiber, hexon and penton genes. Comparative genomics and phylogenetic analysis showed that the newly isolated HAdV-B14 (HAdV-B14 CHN) shared highest sequence homology with a 2006 isolate from the United States and clustered closely with other HAdV-B14 strains. It is expected that data from the present study will help in devising better protocols for virus surveillance, and in developing preventative measures.

Comparative genomics analysis of Mycobacterium ulcerans for the identification of putative essential genes and therapeutic candidates.

Mycobacterium ulcerans, the causative agent of Buruli ulcer, is the third most common mycobacterial disease after tuberculosis and leprosy. The present treatment options are limited and emergence of treatment resistant isolates represents a serious concern and a need for better therapeutics. Conventional drug discovery methods are time consuming and labor-intensive. Unfortunately, the slow growing nature of M. ulcerans in experimental conditions is also a barrier for drug discovery and development. In contrast, recent advancements in complete genome sequencing, in combination with cheminformatics and computational biology, represent an attractive alternative approach for the identification of therapeutic candidates worthy of experimental research. A computational, comparative genomics workflow was defined for the identification of novel therapeutic candidates against M. ulcerans, with the aim that a selected target should be essential to the pathogen, and have no homology in the human host. Initially, a total of 424 genes were predicted as essential from the M. ulcerans genome, via homology searching of essential genome content from 20 different bacteria. Metabolic pathway analysis showed that the most essential genes are associated with carbohydrate and amino acid metabolism. Among these, 236 proteins were identified as non-host and essential, and could serve as potential drug and vaccine candidates. Several drug target prioritization parameters including druggability were also calculated. Enzymes from several pathways are discussed as potential drug targets, including those from cell wall synthesis, thiamine biosynthesis, protein biosynthesis, and histidine biosynthesis. It is expected that our data will facilitate selection of M. ulcerans proteins for successful entry into drug design pipelines.

Computational identification of interplay between phosphorylation and O-ß-glycosylation of human occludin as potential mechanism to impair hepatitis C virus entry.

Hepatitis C virus (HCV) is one of the leading causes of liver diseases. Several host factors that facilitate the attachment and entry of HCV have been discovered, of which human occludin seems to be the most promising. Studies have shown that activity of occludin is dependent upon its phosphorylation status, and that during HCV infection deregulation of phosphorylated occludin collectively leads to a reduction in tight junction (TJ) integrity of hepatocytes and favors HCV entry. However, detailed information of the posttranslational modifications (PTMs) of occludin still remains largely unknown. In addition to phosphorylation, serine/threonine residues of several proteins are also regulated by a unique type of modification known as O-ß-glycosylation and this crosstalk serves as a functional switch. To identify the O-ß-glycosylation potential and how interplay between phosphorylation and O-ß-glycosylation can be exploited for the inhibition of HCV entry, here we report a computational analysis of PTMs of human occludin. Several conserved phosphorylation residues and kinases that can alter the ability of occludin to regulate the integrity of TJs were identified. In addition to previously reported Tyr residues, two additional Tyr residues (Tyr29 and Tyr287) were identified as target sites of Src kinase. To our knowledge, this is the first study to report the O-ß-GlcNAc potential of occludin and target sites of ERK (Ser8, Ser310, and Thr345), GSK-3 (Ser8, Ser341) and Cdk5 (Thr376). Furthermore, based on findings from this study, a potential novel interplay between phosphorylation and O-ß-glycosylation at the two Yin Yang sites (Ser408 and Ser490) is also proposed.

Computational identification and modeling of crosstalk between phosphorylation, O-ß-glycosylation and methylation of FoxO3 and implications for cancer therapeutics.

FoxO3 is a member of the forkhead class of transcription factors and plays a major role in the regulation of diverse cellular processes, including cell cycle arrest, DNA repair, and protection from stress stimuli by detoxification of reactive oxygen species. In addition, FoxO3 is a tumor suppressor and has been considered as a novel target for cancer therapeutics. Phosphorylation of FoxO3 via the AKT, IKK, and ERK pathways leads to deregulation, cytoplasmic retention, degradation of FoxO3 and favors tumor progression. Identification of the amino acid residues that are the target of different posttranslational modifications (PTMs) provides a foundation for understanding the molecular mechanisms of FoxO3 modifications and associated outcomes. In addition to phosphorylation, serine and threonine residues of several proteins are regulated by a unique type of PTM known as O-ß-glycosylation, which serves as a functional switch. We sought to investigate the crosstalk of different PTMs on the FoxO3 which leads to the onset/progression of various cancers and that could also potentially be targeted as a therapeutic point of intervention. A computational workflow and set of selection parameters have been defined for the identification of target sites and crosstalk between different PTMs. We identified phosphorylation, O-ß-GlcNAc modification, and Yin Yang sites on Ser/Thr residues, and propose a potential novel mechanism of crosstalk between these PTMs. Furthermore, methylation potential of human FoxO3 at arginine and lysine residues and crosstalk between methylation and phosphorylation have also been described. Our findings may facilitate the study of therapeutic strategies targeting posttranslational events.

Mycoplasma genitalium: a comparative genomics study of metabolic pathways for the identification of drug and vaccine targets.

Increasing emergence of antibiotic-resistant pathogenic microorganisms is one of the biggest challenges for biomedical research and drug development. Traditional drug discovery methods are time-consuming, expensive and often yield few drug targets. In contrast, advances in complete genome sequencing, bioinformatics and cheminformatics represent an attractive alternative approach to identify drug targets worthy of experimental follow-up. Mycoplasma genitalium is a human parasitic pathogen that is associated with several sexually transmitted diseases. Recently, emergence of treatment-resistant isolates has been reported, which raises serious concern and a need for identification of additional drug targets. In the present study, a systematic workflow consisting of comparative genomics, metabolic pathways analysis and additional drug prioritizing parameters was defined for the identification of novel drug and vaccine targets that are essential for M. genitalium, but absent in its human host. In silico analyses and manual mining identified 79 proteins of M. genitalium, which showed no similarity to human proteins. Among these, 67 proteins were identified as non-homologous essential proteins that could serve as potential drug and vaccine targets. Subcellular localization, molecular weight, and three-dimensional structural characteristics that could facilitate filtering of attractive drug targets were also calculated for the non-homologous essential proteins. Enzymes from thiamine biosynthesis, protein biosynthesis, and folate biosynthesis were identified as attractive candidates for drug development. Furthermore, druggability of each of the identified drug targets was also evaluated by the DrugBank database. Results from this study could facilitate selection of M. genitalium proteins for entry into drug design and vaccine production pipelines.

Role of post translational modifications and novel crosstalk between phosphorylation and O-beta-GlcNAc modifications in human claudin-1, -3 and -4.

The precise characterization of post translational modifications (PTMs) is important for the understanding of protein regulatory mechanisms and their role in disease. However, experimental studies on PTMs, especially with multifunctional proteins are difficult to follow and investigate. Bioinformatic tools are therefore helpful in predicting key protein modifications. To study the role of PTMs in claudin proteins, specifically claudin-1, -3 and -4 in the onset or progression of human cancers, we performed an in silico study of various PTMs and investigated their interplay. Given that the activity of claudins is known to be influenced by two types of PTMs, specifically palmitoylation and kinase- dependent phosphorylation, we predicted two conserved regions in the topological domains of claudin-1, -3 and -4 as potential palmitoylation sites. Furthermore, conserved phosphorylation residues, which may be targets for kinases and can alter claudin's ability to maintain the integrity of tight junctions, were identified. To our knowledge, this is the first report to suggest O-glycosylation of claudin proteins, as well as a potential novel interplay between phosphorylation and O-glycosylation at Yin Yang sites. Thus, our findings may facilitate the production of anti-cancer drugs, and suggest that novel therapeutic strategies should target post translational events.

Comparative sequence, antigenic and phylogenetic analysis of avian influenza (H9N2) surface proteins isolated in Pakistan between 1999 and 2008.

INTRODUCTION: Influenza A viruses possess a unique genomic structure which leads to genetic instability, especially in products of neuraminidase and hemagglutinin genes. These surface proteins play major roles in viral entry and release, and in the activation of the host immune system. METHODOLOGY: This study involved an in silico sequence, phylogenetic and antigenic analyses of hemagglutinin and neuraminidase proteins of avian influenza A (H9N2) strains that circulated in Pakistan's poultry flocks from 1999 to 2008 and determined variations among these sequences at different levels. RESULTS: Sequence and phylogenetic analysis revealed a large number of similar substitution mutations and close evolutionary relation among sequences of both proteins. Changes were observed in the N-glycosylation sites of both surface proteins, along with the appearance of a new glycosylation site in the neuraminidase sequence isolated in 2007. Epitopes for hemagglutinin remained conserved, whereas for neuraminidase, epitopes from older strains reappeared in present sequences. CONCLUSIONS: Because of the rapid mutating nature of avian influenza subtype H9N2, constant surveillance of annual sequence variations is important. Preventive measures and vaccine products can be evaluated by keeping track of changes that may lead to reassortment among different circulating strains in Pakistan's commercial poultry flocks or in humans.

Homology modeling, comparative genomics and functional annotation of Mycoplasma genitalium hypothetical protein MG_237.

Mycoplasma genitalium is a human pathogen associated with several sexually transmitted diseases. The complete genome of M. genitalium G37 has been sequenced and provides an opportunity to understand the pathogenesis and identification of therapeutic targets. However, complete understanding of bacterial function requires proper annotation of its proteins. The genome of M. genitalium consists of 475 proteins. Among these, 94 are without any known function and are described as 'hypothetical proteins'. We selected MG_237 for sequence and structural analysis using a bioinformatics approach. Primary and secondary structure analysis suggested that MG_237 is a hydrophilic protein containing a significant proportion of alpha helices, and subcellular localization predictions suggested it is a cytoplasmic protein. Homology modeling was used to define the three-dimensional (3D) structure of MG-237. A search for templates revealed that MG_237 shares 63% homology to a hypothetical protein of Mycoplasma pneumoniae, indicating this protein is evolutionary conserved. The refined 3D model was generated using (PS)(2)-v2 sever that incorporates MODELLER. Several quality assessment and validation parameters were computed and indicated that the homology model is reliable. Furthermore, comparative genomics analysis suggested MG_237 as non-homologous protein and involved in four different metabolic pathways. Experimental validation will provide more insight into the actual function of this protein in microbial pathways.