Development and evaluation of a SYBR Green real-time RT-PCR assay for detection of avian hepatitis E virus

Identification of a Putative Novel Genotype of Avian Hepatitis E Virus from Apparently Healthy Chickens in Southwestern Nigeria

Avian hepatitis E virus (aHEV) is the major etiological agent of hepatitis-splenomegaly syndrome (HSS), big liver and spleen disease (BLSD), and hepatic rupture hemorrhage syndrome (HRHS) in chickens. Infections with aHEV cause a significant decrease in egg production and increased mortality in chickens worldwide. However, studies on the prevalence of aHEV in Nigeria are scarce. In this study, serum (n = 88) and fecal samples (n = 110) obtained from apparently healthy layer chickens from three states in southwestern Nigeria were analyzed by nested reverse transcription-polymerase chain reaction (nRT-PCR) targeting the helicase and capsid gene for the presence of aHEV. Avian HEV was detected in 12.5% (n = 11/88) of serum samples and 9.1% (n = 10/110) of fecal samples tested. Phylogenetic analysis showed that five of the twelve identified aHEV sequences belonged to genotype 2. The remaining seven sequences were only distantly related to other known aHEV isolates. After amplification of the near-complete ORF2 fragment (1618 bp) and part of the ORF1 (582 bp) of isolate YF40_aHEV_NG phylogenetic analysis revealed a nucleotide sequence identity between 79.0 and 82.6% and 80.1 and 83.5%, respectively, to other known aHEV strains, indicating that the Nigerian isolate YF40_aHEV_NG belongs to a novel aHEV genotype. This is the first report of co-circulation of aHEV genotypes in chickens in Nigeria.

Increased copy number of syncytin-1 in the trophectoderm is associated with implantation of the blastocyst

Background

A key step in embryo implantation is the adhesion to and invasion of the endometrium by the blastocyst trophectoderm. The envelope proteins of HERV-W and -FRD (human endogenous retrovirus-W and -FRD), syncytin-1 and syncytin-2, are mainly distributed in the placenta, and play important roles in the development of the placenta. The placenta originates from the trophectoderm of the blastocyst. It is unclear whether the envelope proteins of HERV-W and -FRD have an effect on the development of the trophectoderm and whether they have any association with the implantation of the blastocyst.

Methods

The whole-genome amplification products of the human blastocyst trophectoderm were used to measure the copy number of syncytin-1 and syncytin-2 using real time qPCR. In addition, clinical data associated with the outcome of pregnancies was collected, and included age, body mass index (BMI), basic follicle stimulating hormone(bFSH), rate of primary infertility and oligo-astheno-teratospermia, the thickness of the endometrium on the day of endometrial transformation, the levels of estrogen and progestin on the transfer day, the days and the morphological scores of the blastocysts. The expression of mRNA and the copy numbers of syncytin-1 and syncytin-2 in H1 stem cells, and in differentiated H1 cells, induced by BMP4, were measured using real time qPCR.

Results

The relative copy number of syncytin-1 in the pregnant group (median: 424%, quartile: 232%-463%, p < 0.05) was significantly higher than in the non-pregnant group (median: 100%, quartile: 81%-163%). There was a correlation (r _s  = 0.681, p < 0.001) between the copy number of syncytin-1 and blastocyst implantation after embryo transfer. As the stem cells differentiated, the expression of NANOG mRNA decreased, and the expression of caudal type homeobox 2(CDX2) and β-human chorionic gonadotropin (β-hCG) mRNAs increased. Compared to the undifferentiated cells, the relative expression of the syncytin-1 mRNA was 1.63 (quartile: 0.59-6.37, p > 0.05), 3.36 (quartile: 0.85-14.80, p > 0.05), 10.85 (quartile: 3.39-24.46, p < 0.05) and 67.81 (quartile: 54.07-85.48, p < 0.05) on day 1, 3, 5 and 7, respectively, after the differentiation. The relative expression of syncytin-2 was 5.34 (quartile: 4.50-10.30), 7.90 (quartile: 2.46-14.01), 57.44 (quartile: 38.35-103.87) and 344.76 (quartile: 267.72-440.10) on day 1, 3, 5 and 7, respectively, after the differentiation (p < 0.05). The copy number of syncytin-1 increased significantly during differentiation.

Conclusion

Preceding the transfer of frozen embryos, the increased copy number of syncytin-1 in the blastocyst trophectoderm was associated with good outcomes of pregnancies.

Complete genome analysis of avian hepatitis E virus from chicken with hepatic rupture hemorrhage syndrome

Since 2016, severe outbreaks of hepatic rupture hemorrhage syndrome (HRHS) associated with infections of tentative novel avian hepatitis E virus (HEV) have emerged in chickens in China, causing increased mortality and decreased laying rate in adult hens and disturbing the hatching and breeding of chicks. To further identify the genotype and gain a better understanding of the genetic properties of the avian HEV responsible for that, a strain from Hebei province was isolated, purified and sequenced in this study. Results identified a novel avian HEV genotype, sharing 79.5-86.9% identities with other published avian HEV strains, and having higher identities with Orthohepevirus A HEV strains. More importantly, the new isolate contains various amino-acid substitutions in its functional proteins, including methyltransferase, helicase, RNA-dependent RNA polymerase. The data presented in this report will enhance the current understanding of the genetic diversity of the avian HEV and provide additional insight into the critical factors that determine the pathogenicity.

Histologic findings and viral antigen distribution in natural coinfection of layer hens with subgroup J avian leukosis virus, Marek's disease virus, and reticuloendotheliosis virus

We investigated the histologic findings and viral antigen distribution in 3 cases of natural coinfection of layer hens with subgroup J avian leukosis virus (ALV-J), Marek's disease virus (MDV), and reticuloendotheliosis virus (REV) in hens. At autopsy, diseased hens were found to have hepatosplenomegaly and thickened proventriculi, with white tumor nodules in the liver, spleen, lung, kidney, and ovary. Microscopically, most tissues had been infiltrated by neoplastic lymphocytes; the spleen, lung, proventriculus, heart, and liver had been infiltrated by both neoplastic lymphocytes and myeloblastic cells and/or primitive reticular cells. Fluorescence multiplex immunohistochemistry staining revealed ALV-J, MDV, and REV antigens co-expressed in the same tissue, even the same cell.

Epidemiological investigation of the novel genotype avian hepatitis E virus and co-infected immunosuppressive viruses in farms with hepatic rupture haemorrhage syndrome, recently emerged in China

Since 2016, hepatic rupture haemorrhage syndrome (HRHS) appeared in chickens of China and caused huge economic loss. To assess the infection status of the avian hepatitis E virus (HEV) and co-infected viruses, including avian leukosis virus (ALV), reticuloendotheliosis virus (REV), fowl adenovirus (FAdV), and chicken infectious anaemia virus (CIAV), in farms with HRHS, 180 liver samples were collected from 24 farms in different provinces and detected by strict molecular virology methods. Results showed that the positive rates of HEV, ALV, REV, FAdV, and CIAV were 74.44%, 20.00%, 27.78%, 31.11%, and 12.22%, respectively, whereas there are also 112 samples with co-infection, for a rate of 58%. Meanwhile, the positive rate of HEV decreased gradually with age; the lowest positive rate of ALV (5.76%) and REV (19.23%) appeared in 25-35 weeks age, during which the positive rate of CIAV was the highest (19.23%); the positive rate of HEV in layers (64.00%) was lower than that of broilers (83.33%), but the positive rates of ALV (38.46%) and CIAV (15.38%) in layers were higher than that of broilers (5.88%, 9.80%); the positive rates of HEV (75.88%) and CIAV (15.60%) in parental generation (PG) were higher than that of commodity generation (CG, 64.10%, 0.00%), whereas the positive rate of ALV showed inverse relationship (PG: 14.89%; CG: 38.46%). Additionally, phylogenetic analysis showed that all the avian HEV identified this study belong to a novel genotype, and found the close relationship between the wild strains (REV and CIAV) and corresponding isolates from contaminated vaccine. The data presented in this report will enhance the current understanding of the epidemiology characteristics in farms with HRHS in China.

Infection with phytopathogenic bacterium inhibits melatonin biosynthesis, decreases longevity of its vector, and suppresses the free radical-defense

Vector-borne phytopathogenic bacteria may alter the reproductive fitness, survival, behavior, and metabolism of their vectors. Candidatus Liberibacter asiaticus (CLas) is associated with the Huanglongbing (also known as citrus greening disease), one of the most destructive citrus diseases worldwide, and transmitted by Asian citrus psyllid, Diaphorina citri (Insecta, Hemiptera, Liviidae). The genome sequencing of CLas revealed that it does not have the ability to synthesize tryptophan, the precursor of melatonin, and it must acquire it from its host plant or insect vector to achieve its biologic processes, such as growth and multiplication. Herein, we aimed to develop a GC-MS-SIM-based method to detect the endogenous melatonin from small insects such as D. citri, and to explore the hidden relationship between melatonin content and D. citri-adult survival. Then, we studied the ability of exogenous melatonin supplementation to reverse the negative effects of CLas-infection. Our findings showed that CLas-infection reduced the levels of melatonin and its biosynthetic genes (DcTPHs, DcAAAD, DcSNAT, and DcASMT) of D. citri compared to uninfected insects. In addition, CLas decreased the longevity of its vector, D. citri via the suppression of the free radical-defense associated genes (SODs, GSTs, PODs, and PHGPXs). On the other hand, melatonin supplementation could reverse the negative effects of CLas-infection. Melatonin supplementation enhanced the endogenous melatonin content, melatonin biosynthetic genes, free radical-defense associated genes, and the longevity of both healthy and CLas-infected D. citri. Furthermore, melatonin supplementation decreased the CLas bacterial population within the D. citri psyllids. Based on these findings, we hypothesize that melatonin plays multi-layered defensive roles in D. citri. These roles include acting as a natural antioxidant or as an antibacterial compound.

Live recombinant Lactococcuslactis expressing avian hepatitis virus ORF2 protein: Immunoprotection against homologous virus challenge in chickens

Avian hepatitis E virus (aHEV) is a pathogen associated with hepatitis-splenomegaly syndrome in chickens. To date, no commercial vaccine is available for preventing aHEV infection. In this study, three recombinant LactococcuslactisNZ9000experimental live vaccines expressing cytoplasmic, secreted, and cell wall-anchored forms of aHEV truncated ORF2 protein spanning amino acids 249-606 (ΔORF2) were constructed using pTX8048 vector and characterized. Each chicken was immunized three times at two-week intervals with one of the three live aHEV ORF2 vaccines (experimental group) or with live vaccine containing empty vector only (control group). Both groups were then challenged with aHEV and evaluated to compare immune responses and immunogenic effects. Serum IgG levels, secretory IgA (sIgA) levels in bile and jejunal lavage fluid, and mRNA expression levels ofIL-2 and IFN-γ in liver and spleen were significantly higher in experimental chickens than in controls. Meanwhile, post-challenge serum and fecal virus loads were significantly lower in experimental chickens versus controls. Moreover, on day 7 post infection (PI), serum lactose dehydrogenase (LDH) levels were significantly higher in controls than experimental chickens. Furthermore, at day 28 PI, obvious gross pathological lesions and histopathological changes typical for aHEV infection were observed in control livers and spleens, with only moderate pathological changes observed in the experimental group. The results of this study collectively demonstrate that an oral vaccineusing L.lactisNZ9000 as a delivery vector for aHEV immunogenic antigen could effectively control aHEV infection of chickens.

Hepatic rupture hemorrhage syndrome in chickens caused by a novel genotype avian hepatitis E virus

Since 2016, severe outbreaks of hepatic rupture hemorrhage syndrome (HRHS) have emerged in chickens in several Chinese provinces and caused huge economic losses to the poultry industry, but the etiological characteristics and pathogenic potential of it has remained unclear. This study sequenced the partial helicase and capsid gene of the potentially novel avian hepatitis E virus (HEV) isolated from chickens with HRHS and tested the pathogenicity of it on SPF chicks, while the appearance of clinical signs, histopathological changes, viral distribution, viremia and viral shedding were monitored for 14 days post-infection (dpi). Analysis revealed that the HRHS related avian HEV belongs to a novel genotype, and infected chicks developed the typical symptoms of HRHS. Thus, this study successfully developed an experimental infection model for studying the pathogenicity and role of the novel avian HEV in HRHS. Meanwhile, the novel avian HEV mainly existed in the liver and spleen, inducing a rapid viremia and chronic viral shedding in infected chicks, and could cause 40% mortality before 14 dpi. In conclusion, this study found the novel genotype avian HEV and confirmed its role in HRHS.

Laboratory challenges in the diagnosis of hepatitis E virus

Hepatitis E virus (HEV) is an RNA virus that is an important cause of both acute and chronic hepatitis worldwide. To date, there are eight HEV genotypes that can infect mammals. HEV-1 and HEV-2 infect exclusively humans, while HEV-3 and HEV-4 infect humans and various animals, mainly pigs and deer. Additionally, two new genotypes (HEV-5 and HEV-6) infect mainly wild boar. Recently, newly discovered genotypes HEV-7 and HEV-8 were found to infect camels and possibly humans. Nevertheless, the epidemiological distribution of HEV-7 is not well established. HEV-8 is another newly discovered genotype that was identified in 2016 in Chinese Bactrian camels. Although faecal-oral transmission is the most common route of HEV transmission, HEV can be vertically transmitted from infected mothers to their fetuses. HEV may also spread by zoonotic transmission from infected animals to humans and through person-to-person contact. Nowadays, since the number of reported cases linked to blood donations is increasing annually, HEV is recognized as a transfusion-transmitted virus. Laboratory diagnostic techniques vary in their specificity and sensitivity for HEV detection. Direct techniques allow for detection of the viral proteins, antigens and viral nucleic acid, while HEV-specific IgG and IgM antibodies can help establish a diagnosis in acute and chronic infections. In this review, we will discuss recent technologies in the laboratory diagnosis of HEV, including serological and molecular methods to assess the specificity and sensitivity of currently available HEV commercial assays.

Jian-Pi-Zhi-Dong-Decoction regulates the expression of glutamate transporters to attenuate glutamate excitotoxicity and exerts anti-tics effects in Tourette syndrome model rats

PURPOSE

This study explored whether Jian-Pi-Zhi-Dong-Decoction (JPZDD) could regulate the metabolism of glutamate (GLU) and its transporters in the striatum to exert anti-tics effects in Tourette syndrome (TS) rats.

MATERIALS AND METHODS

We randomly assigned 56 Sprague Dawley rats into four groups, each with 14 rats: control, model, tiapride (Tia), and JPZDD. TS groups (model, Tia, and JPZDD) received intraperitoneal injection of 3,3'-iminodipropionitrile for 7 days to establish TS model. Thereafter, rats in the four groups were treated differently once a day for 6 weeks. Behavioral evaluation was performed each week by using stereotypy recording and autonomic activity test. The level of GLU in the striatum was examined by high-performance liquid chromatography. Expression of EAAT1 and VGLUT1 were measured by quantitative real-time PCR (qRT-PCR) and laser scanning confocal microscope.

RESULTS

Compared with the model group, the stereotypy score and autonomic activity were decreased in Tia and JPZDD groups. Notably, the model group had increased concentration of GLU, which decreased after JPZDD and Tia treatments. In the model group, EAAT1 and glial cells were highly co-expressed and the relative fluorescence intensity (FI) of EAAT1 was significantly lower than that in the control group. Treatment with JPZDD and Tia increased the relative FI of EAAT1. The mRNA level of EAAT1 decreased in the model group compared to that in the control group, although it was significantly elevated following JPZDD or Tia treatment. In the model group, there was low co-expression of VGLUT1 and axon cells and the FI of VGLUT1 was remarkably increased relative to that in the control group and reduced following treatment with JPZDD and Tia. A similar trend was observed in the mRNA and protein expression of VGLUT1, although it was not statistically significant.

CONCLUSION

The mechanism by which JPZDD alleviated behavioral dysfunction of TS rats may be associated with maintaining normal GLU transport by upregulating EAAT1 and down-regulating VGLUT1 in the striatum.

A Plant Bacterial Pathogen Manipulates Its Insect Vector's Energy Metabolism

Insect-transmitted plant-pathogenic bacteria may alter their vectors' fitness, survival, behavior, and metabolism. Because these pathogens interact with their vectors on the cellular and organismal levels, potential changes at the biochemical level might occur. "Candidatus Liberibacter asiaticus" (CLas) is transmitted in a persistent, circulative, and propagative manner. The genome of CLas revealed the presence of an ATP translocase that mediates the uptake of ATP and other nucleotides from medium to achieve its biological processes, such as growth and multiplication. Here, we showed that the levels of ATP and many other nucleotides were significantly higher in CLas-infected than healthy psyllids. Gene expression analysis showed upregulation for ATP synthase subunits, while ATPase enzyme activity showed a decrease in ATPase activity. These results indicated that CLas stimulated Diaphorina citri to produce more ATP and many other energetic nucleotides, while it may inhibit their consumption by the insect. As a result of ATP accumulation, the adenylated energy charge (AEC) increased and the AMP/ATP and ADP/ATP ratios decreased in CLas-infected D. citri psyllids. Survival analysis confirmed a shorter life span for CLas-infected D. citri psyllids. In addition, electropenetrography showed a significant reduction in total nonprobing time, salivation time, and time from the last E2 (phloem ingestion) to the end of recording, indicating that CLas-infected psyllids were at a higher hunger level and they tended to forage more often. This increased feeding activity reflects the CLas-induced energetic stress. In conclusion, CLas alters the energy metabolism of its psyllid vector, D. citri, in order to secure its need for energetic nucleotides.IMPORTANCE Insect transmission of plant-pathogenic bacteria involves propagation and circulation of the bacteria within their vectors. The transmission process is complex and requires specific interactions at the molecular and biochemical levels. The growth of the plant-pathogenic bacteria in the hemolymph of their vectors indicated that the hemolymph contains all the necessary nutrients for their growth. In addition to nutrients, "Candidatus Liberibacter asiaticus" (CLas) can take up energetic nucleotides, such as ATP, from its vector, Diaphorina citri, using ATP translocase. In this study, we found that the CLas pathogen manipulates the energy metabolism of its insect vector. The accumulation of ATP in CLas-infected D. citri psyllids indicated that CLas induces ATP production to fulfill its need for this energetic compound. As a result of ATP accumulation, a shorter life span and altered feeding behavior were observed. These findings increase our knowledge of insect transmission of the persistent-circulative-propagative type of plant pathogens vectored by insects.

Panax notoginseng saponins provide neuroprotection by regulating NgR1/RhoA/ROCK2 pathway expression, in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng saponins (PNS) extracted from a traditional Chinese herbal medicine, Panax notoginseng (Burkill) F.H. Chen (Araliaceae), which has been extensively used in treating coronary heart disease, ischemic cerebrovascular disease and hemorrhagic disorders in China over hundreds of years.

AIMS OF THE STUDY

This study explored whether panax notoginseng saponins (PNS) provided neuroprotective effects by inhibiting the expressions of NgR1, RhoA, and ROCK2 following middle cerebral artery occlusion in rats and oxygen-glucose deprivation/reoxygenation (OGD/R) injury in SH-SY5Y cells.

MATERIALS AND METHODS

2,3,5-Triphenyltetrazolium chloride staining was used to determine successful middle cerebral artery occlusion establishment in sham-operated and operated Sprague-Dawley rats 1 day after injury. The rats were randomly separated into sham, model, NEP1-40, PNS, and NEP1-40 plus PNS (N+P) groups. After 7 days of treatment, body mass and neurological deficit scores were analyzed. Tissues were harvested and analyzed by hematoxylin-eosin staining and immunohistochemical analysis, western blotting, and quantitative real-time PCR (qRT-PCR). The optimal drug concentration of NEP1-40 and PNS on SH-SY5Y cells exposed to OGD/R injury was determined by CCK8 analysis. qRT-PCR was used to measure mRNA expression profiles of NgR1, RhoA, and ROCK2 in SH-SY5Y cells subjected to OGD/R.

RESULTS

The results showed that MCAO surgery successfully produced an infarct, and the PNS, NEP1-40, and N+P groups exhibited increased body mass and ameliorated neurological deficits compared with the model group. NEP1-40 treatment markedly reduced NgR1 and RhoA overexpression when compared to the model group, although there was no significant difference in ROCK2 expression. PNS and N+P treatment significantly decreased NgR1, RhoA, and ROCK2 overexpression compared with the model group. However, N+P treatment did not result in a synergistic effect, as assessed by immunohistochemistry, western blotting, and qRT-PCR. Following optimal administration of PNS (160μg/ml) and NEP1-40 (10ng/ml) on SH-SY5Y cells exposed to OGD/R injury, cell viability in the NEP1-40, PNS, and N+P groups significantly increased compared with the model group, as assessed by CCK8 analysis. Additionally, NgR1, RhoA, and ROCK2 mRNA expression profiles were significantly less in the NEP1-40, PNS, and N+P groups compared with the model group.

CONCLUSION

PNS provided neuroprotective effects in a rat model of cerebral ischemia and SH-SY5Y cells exposed to oxygen/glucose deprivation injury by inhibiting the overexpression of NgR1, RhoA, and ROCK2.