Clostridium butyricum improves cognitive dysfunction in ICV-STZ-induced Alzheimer's disease mice via suppressing TLR4 signaling pathway through the gut-brain axis.

In recent years, the relationship between gut-brain axis and Alzheimer's disease (AD) attracted increasing attention. The aim of this study is to investigate the therapeutic effect of Clostridium butyricum (CB) on intraventricular injection of streptozotocin (ICV-STZ)-induced mice and the potential mechanisms. ICV-STZ mice were treated with CB by gavage for 21 consecutive days. The pharmacological effect of CB was assessed by behavior test, brain tissue H&E staining and tau protein phosphorylation levels of hippocampus tissues. The expression levels of TLR4, MYD88, NF-κB p65, TNF-α, iNOS, Occludin and ZO-1 in hippocampal and colonic tissues were detected by Western-blot method. 16S rRNA gene sequencing analysis was used to analyze the intestinal microbiota of mice. The results showed that CB improved the cognitive dysfunction of ICV-STZ mice, restored the structure and cell number of hippocampal and cortical neurons, decreased the protein levels of pSer404-tau protein in hippocampal tissues and TLR4, MYD88, NF-κB p65 and iNOS in hippocampal and colonic tissues, and increased the protein levels of Occludin and ZO-1 in colonic tissues. Meanwhile, CB reversed the changes of intestinal microbiota in AD mice. Therefore, the mechanisms of cognitive function and brain pathological changes in AD mice improved by CB may be related to the regulation of TLR4 signaling pathway and intestinal microbiota. This study supports the potential anti-AD effect of CB and initially revealed its pharmacological mechanism of CB, providing a theoretical basis for further clinical application of CB.

Design, synthesis and in vitro/in vivo anticancer activity of tranylcypromine-based triazolopyrimidine analogs as novel LSD1 inhibitors.

Histone lysine specific demethylase 1 (LSD1) is responsible for the demethylation of mono-/dimethylated lysine residue on histone proteins. LSD1 plays an extensive and essential role in the pathogenesis and progression of many human diseases such as cancers, and thus is becoming an attractive therapeutic target for cancer treatment. Tranylcypromine (TCP) is an important chemical template for developing irreversible LSD1 inhibitors, representing a major chemotype of clinical candidates. Here we report a novel pool of TCP derivatives with triazolopyrimidine as a privileged heterocylic motif. Starting from ticagrelor, a clinically available antiplatelet agent, as a hit compound, our medicinal efforts have led to the identification of compound 9j with nanomolar inhibitory potency against LSD1 as well as broad-spectrum antiproliferative activities against tumor cells. Enzyme studies show that compound 9j is selective over MAO-A/B enzymes, and also cellular active to elevate the expression of H3K4me2 by inhibiting LSD1 in cells. Furthermore, in a H1650 xenograft mouse model, oral administration of compound 9j at low 10 and 20 mg/kg dosages could enable a significant reduction in tumor size and a remarkable extension of survival. The current work is expected to provide an additional strategy to achieve new TCP-based LSD1 inhibitors.

Inhibition of ferroptosis through regulating neuronal calcium homeostasis: An emerging therapeutic target for Alzheimer's disease.

Alzheimer's disease (AD), a chronic and progressive neurodegenerative disease, generates a serious threat to the health of the elderly. The AD brain is microscopically characterized by amyloid plaques and neurofibrillary tangles. There are still no effective therapeutic drugs to restrain the progression of AD though much attention has been paid to exploit AD treatments. Ferroptosis, a type of programmed cell death, has been reported to promote the pathological occurrence and development of AD, and inhibition of neuronal ferroptosis can effectively improve the cognitive impairment of AD. Studies have shown that calcium (Ca2+) dyshomeostasis is closely related to the pathology of AD, and can drive the occurrence of ferroptosis through several pathways, such as interacting with iron, and regulating the crosstalk between endoplasmic reticulum (ER) and mitochondria. This paper mainly reviews the roles of ferroptosis and Ca2+ in the pathology of AD, and highlights that restraining ferroptosis through maintaining the homeostasis of Ca2+ may be an innovative target for the treatment of AD.

Radix Rehmanniae Praeparata (Shu Dihuang) exerts neuroprotective effects on ICV-STZ-induced Alzheimer's disease mice through modulation of INSR/IRS-1/AKT/GSK-3ß signaling pathway and intestinal microbiota.

Radix Rehmanniae Praeparata (RRP, Shu Dihuang in Cinese) is widely used as primal medicine in Chinese herbal formula for the treatment of Alzheimer's disease (AD). However, the underlying mechanism of RRP for AD remains unclear. The aim of this study was to investigate the therapeutic effect of RRP on intracerebroventricular injection of streptozotocin (ICV-STZ)-induced AD model mice and its potential mechanism. ICV-STZ mice were continuously gavaged with RRP for 21 days. The pharmacological effects of RRP were evaluated by behavioral tests, brain tissue H&E staining and hippocampal tau protein phosphorylation levels. The expression levels of insulin receptor (INSR), IRS-1, pSer473-AKT/AKT and pSer9-GSK-3ß/GSK-3ß proteins in hippocampal and cortical tissues were detected by Western-blot method. The 16S rRNA gene sequencing was used to analyze the changes of intestinal microbiota in mice. The compounds in RRP were analyzed by mass spectrometry and their binding ability to INSR proteins was detected by molecular docking. The results showed that RRP ameliorated cognitive dysfunction and neuronal pathological changes of brain tissue in ICV-STZ mice, reduced tau protein hyperphosphorylation, INSR, IRS-1, pSer473-AKT/AKT, and pSer9-GSK-3ß/GSK-3ß levels in hippocampal and cortical tissues. Meanwhile, RRP reversed ICV-STZ-induced dysregulation of intestinal microbiota in AD mice. Mass spectrometry analysis showed that the RRP consisted mainly of seven compounds, namely Acteoside (Verbascoside), 5-Hydroxymethyl-2-furaldehyde (5-HMF), Apigenin7-O-glucuronide, Icariin, Gallic acid, Quercetin-3ß-D-glucoside, and Geniposide. Molecular docking results further indicated that the compounds in RRP have binding ability to INSR protein and potential multiple synergistic effects. RRP ameliorates cognitive dysfunction and brain histopathological changes in AD mice. The mechanism of RRP ameliorating AD may be related to the regulation of INSR/IRS-1/AKT/GSK-3ß signaling pathway and intestinal microbiota. This study supports the potential anti-AD efficacy of RRP and initially reveals the pharmacological mechanism of RRP, providing a theoretical basis for further clinical application of RRP.

LiuweiDihuang improved cognitive functions in SAMP8 mice by inhibiting COX-2 expression and subsequent neuroinflammation.

ETHNOPHARMACOLOGICAL RELEVANCE: LiuweiDihuang (LW) pills was mainly used to treatment of children's fontanelle incomplete closure, enuresis and nervous system development delays and other diseases.Following the deepening of pharmacological research, LW has a good effect on neurological diseases include senile dementia. However, the neuroprotection mechanism of LW on Alzheimer's disease (AD) through regulation of inflammation remains unclear. AIM OF THE STUDY: Here, we aimed to explore the effects and mechanism of LW on learning and memory deficits in SAMP8 mice. MATERIALS AND METHODS: Mice aged 6 months were treated with LW for 2 months and BV2, C6 and HT22 cells were treated with LW pharmaceutic serum and Lipopolysaccharide (LPS) continuously. Then, cognitive tests were performed, including the Morris water maze and Y maze tests. The mRNA level of cyclooxygenase 2 (COX-2) and pro-inflammatory factors (IL-1ß, IL-6 and TNF-α) were examined in cells and the cortex and hippocampus by quantitative RT-PCR. The expression of postsynaptic density protein 95, synaptophysin and various inflammatory factors were detected in the cortex and hippocampus by Western blot. Furthermore, Ionized calcium binding adapter molecule 1, glial fibrillary acidic protein and Aß were examined in the brain of AD mice by immunofluorescence staining and immunohistochemistry. And synaptic loss and neuronal ultrastructure were observed by transmission electron microscope. RESULTS: We found that LW suppressed LPS-induced COX-2 expression in vitro. Importantly, LW dramatically improved spatial learning and memory in SAMP8 mice through inhibiting Aß accumulation and restoring structural synaptic integrity. Furthermore, LW inhibited the glial activation and neuroinflammation (COX-2, IL-1ß, IL-6 and TNF-α) in the cortex and hippocampus of SAMP8 mice. CONCLUSION: Taken together, the present data not only indicated that LW is an effective agent on improving the learning and memory deficits through mitigating neuroinflammation but highlighted the LW can be a potential therapeutic drug for AD therapy.

Cholecystokinin and glucagon-like peptide-1 analogues regulate intestinal tight junction, inflammation, dopaminergic neurons and α-synuclein accumulation in the colon of two Parkinson's disease mouse models.

Parkinson's disease (PD) is the second most common neurodegenerative disease, and no treatment is available to stop its progression. Studies have shown that the colonic pathology of PD precedes that of the brain. The 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model and the human A53T α-synuclein (α-syn) transgenic PD mouse model show colonic pathology and intestinal dopaminergic neuronal damage, which is comparable to the intestinal pathology of PD. Cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1), which are brain-gut peptides, have neurotrophic and anti-inflammatory properties. Two GLP-1R agonists have already shown robust effects in phase II trials in PD patients. However, whether they have beneficial effects on colonic pathology in PD remains unclear. In this study, MPTP-treated mice and human A53T α-syn transgenic mice were intraperitoneally injected with a CCK analogue or Liraglutide, a GLP-1 analogue, once a day for 5 weeks. Levels of colonic epithelial tight junction proteins including occludin and zonula occludens-1 (ZO-1), inflammatory biomarkers including inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α), brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH) and α-syn were analyzed. The results show that the CCK analogue and Liraglutide both restored the disruption of intestinal tight junction, reduced colonic inflammation, inhibited colonic dopaminergic neurons reduction and the accumulation of α-syn oligomers in the colon of both PD mice models. This study suggested that CCK or GLP-1 analogues could be beneficial to the improvement of leaky gut barrier, inflammation, dopaminergic neuron impairment and accumulation of α-syn in the colon of PD patients.

Neuroprotective Effects of a Cholecystokinin Analogue in the 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Parkinson's Disease Mouse Model.

Parkinson's disease (PD) is a chronic neurodegenerative disease. Type 2 diabetes mellitus (T2DM) has been identified as a risk factor for PD. Drugs originally developed for T2DM treatment such as liraglutide have shown neuroprotective effects in mouse models of PD. Cholecystokinin (CCK) is a peptide hormone with growth factor properties. Here, we demonstrate the neuroprotective effects of the (pGLu)-(Gln)-CCK8 analogue in an acute PD mouse model induced by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Administration of CCK analogue (50 nmol/kg ip.) for 14 days treatment improved the locomotor and exploratory activity of mice, and improved bradykinesia and movement balance of mice. The CCK analogue administration also restored tyrosine hydroxylase (TH) positive dopaminergic neurons number and synapse number (synaptophysin levels) in the substantia nigra pars compacta (SNpc). The CCK analogue decreased glia activation and neuroinflammation in the SNpc, and regulated autophagy dysfunction induced by MPTP. CCK analogue protected against mitochondrial damage and ER stress, and also decreased the ratio of apoptosis signaling molecules Bax/Bcl-2. Importantly, the CCK analogue improved the decrease of p-CREBS133 growth factor signaling in the SNpc. Therefore, the CCK analogue promotes cell survival of dopaminergic neuron in the SNpc by activating the cAMP/PKA/CREB pathway that also inhibits apoptosis and regulates autophagy impairment. The present results indicate that CCK analogue shows a promising potential for the treatment of PD.

Zexie Tang targeting FKBP38/mTOR/SREBPs pathway improves hyperlipidemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Zexie Tang (ZXT), only two consists with Alismatis Rhizoma (AR) and Atractylodes macrocephala Rhizoma (AM), a classical Chinese medicine formula from Synopsis of the Golden Chamber with a history of 2000 years. Clinical observation in recent years has found that ZXT has excellent lipid-lowering effect. AIM OF THE STUDY: To explore the potential mechanism of ZXT ameliorates hyperlipidemia based on FKBP38/mTOR/SREBPs pathway. MATERIALS AND METHODS: WD-induced hyperlipidemia mice and oleic acid induced cell lipid accumulation model were used to investigate pharmacodynamic. The effect of ZXT on the transcriptional activity of SREBPs was detected by reporter gene assay. Proteins and downstream genes of mTOR/SREBPs pathway were detected in vivo and in vitro. Combined with network pharmacology and HPLC-Q-TOF/MS, the active ingredients were screened and identified. The interaction between active compounds of ZXT and FKBP38 protein were analyzed by docking analysis. RESULTS: ZXT decreased TC, TG and LDL-c levels in blood of WD-induced hyperlipidemia mouse model, and improved insulin resistance in vivo. ZXT also reduced TC, TG and lipid accumulation in cells line, and inhibited SREBPs luciferase activity, protein and its target genes expression such as FASN, HMGCR, etc. Meanwhile, ZXT inhibited protein expression levels of p-mTOR, p-S6K, etc in vitro and in vivo. Combined with network pharmacology and HPLC-Q-TOF/MS, 16 active ingredients were screened and identified. Docking results showed that active compounds of ZXT binding to FKBP38 and formed hydrogen bond. CONCLUSION: Our findings highlighted that ZXT ameliorates hyperlipidemia, in which FKBP/mTOR/SREBPs pathway might be the potential regulatory mechanism.

A GLP-2 Analogue Protects SH-SY5Y and Neuro-2a Cells Against Mitochondrial Damage, Autophagy Impairments and Apoptosis in a Parkinson Model.

Glucagon-like peptide-2 (GLP-2) is a peptide hormone that belongs to the glucagon-derived peptide family. We have previously shown that analogues of the sister hormone Glucagon-like peptide-1 (GLP-1) showed neuroprotective effects. Here we investigated the effect of a GLP-2 agonist in a cell model of Parkinson's disease (PD) created by treating SH-SY5Y or Neuro-2a cells with 1-Methyl-4-phenyl-pyridine ion (MPP+). Cell viability and cell cytotoxicity was detected by MTT and LDH assays, respectively. The protein expression levels of mitochondrial, autophagy and apoptotic biomarkers including PGC-1α, Mfn2, IRE1, ATG7, LC3B, Beclin1 and Bcl-2 were detected by western blot. Mitochondrial superoxide was detected by MitoSOX Red. In addition, mitochondrial morphology, autophagosome and apoptotic corpuscles were observed by transmission electron microscope (TEM). We found that the GLP-1 and the GLP-2 agonists both protect cells against mitochondrial damage, autophagy impairments and apoptosis induced by MPP+both in SH-SY5Y and Neuro-2a cells. Cell signaling for mitogenesis was enhanced, and oxidative stress levels much reduced by the drugs. This demonstrates for the first time the neuroprotective effects of a GLP-2 analogue in PD cellular models, in which oxidative stress, autophagy and apoptosis play crucial roles. The protective effects were comparable to those seen with the GLP-1 analogue liraglutide. The results suggest that not only GLP-1, but also GLP-2 has neuroprotective properties and may be useful as a novel treatment of PD.

Engineering a Live Attenuated Porcine Epidemic Diarrhea Virus Vaccine Candidate via Inactivation of the Viral 2'-O-Methyltransferase and the Endocytosis Signal of the Spike Protein.

Porcine epidemic diarrhea virus (PEDV) causes high mortality in neonatal piglets; however, effective and safe vaccines are still not available. We hypothesized that inactivation of the 2'-O-methyltransferase (2'-O-MTase) activity of nsp16 and the endocytosis signal of the spike protein attenuates PEDV yet retains its immunogenicity in pigs. We generated a recombinant PEDV, KDKE4A, with quadruple alanine substitutions in the catalytic tetrad of the 2'-O-MTase using a virulent infectious cDNA clone, icPC22A, as the backbone. Next, we constructed another mutant, KDKE4A-SYA, by abolishing the endocytosis signal of the spike protein of KDKE4A Compared with icPC22A, the KDKE4A and KDKE4A-SYA mutants replicated less efficiently in vitro but induced stronger type I and type III interferon responses. The pathogenesis and immunogenicities of the mutants were evaluated in gnotobiotic piglets. The virulence of KDKE4A-SYA and KDKE4A was significantly reduced compared with that of icPC22A. Mortality rates were 100%, 17%, and 0% in the icPC22A-, KDKE4A-, and KDKE4A-SYA-inoculated groups, respectively. At 21 days postinoculation (dpi), all surviving pigs were challenged orally with a high dose of icPC22A. The KDKE4A-SYA- and KDKE4A-inoculated pigs were protected from the challenge, because no KDKE4A-SYA- and one KDKE4A-inoculated pig developed diarrhea whereas all the pigs in the mock-inoculated group had severe diarrhea, and 33% of them died. Furthermore, we serially passaged the KDKE4A-SYA mutant in pigs three times and did not find any reversion of the introduced mutations. The data suggest that KDKE4A-SYA may be a PEDV vaccine candidate.IMPORTANCE PEDV is the most economically important porcine enteric viral pathogen and has caused immense economic losses in the pork industries in many countries. Effective and safe vaccines are desperately required but still not available. 2'-O-MTase (nsp16) is highly conserved among coronaviruses (CoVs), and the inactivation of nsp16 in live attenuated vaccines has been attempted for several betacoronaviruses. We show that inactivation of both 2'-O-MTase and the endocytosis signal of the spike protein is an approach to designing a promising live attenuated vaccine for PEDV. The in vivo passaging data also validated the stability of the KDKE4A-SYA mutant. KDKE4A-SYA warrants further evaluation in sows and their piglets and may be used as a platform for further optimization. Our findings further confirmed that nsp16 can be a universal target for CoV vaccine development and will aid in the development of vaccines against other emerging CoVs.

The enhanced replication of an S-intact PEDV during coinfection with an S1 NTD-del PEDV in piglets.

Porcine epidemic diarrhea virus (PEDV) variants having a large deletion in the N-terminal domain of the S1 subunit of spike (S) protein were designated as S1 NTD-del PEDVs. They replicate well in experimentally infected pigs. However, on farms they often co-infect pigs with the PEDV containing an intact S protein (S-intact PEDV). We aimed to characterize viral replication and pathogenesis in neonatal gnotobiotic pigs infected simultaneously with the two types of PEDV using two recombinant PEDVs: icPC22A and its S1 NTD-del form icPC22A-S1Δ197. Additionally, viral replication was compared in Vero and IPEC-DQ cells at the presence of bovine mucin (BM), porcine gastric mucin (PGM), swine bile and bile acids during inoculation. In the pigs coinfected with icPC22A and icPC22A-S1Δ197, icPC22A replicated to a higher peak titer than its infection of pigs without the presence of icPC22A-S1Δ197. The severity of diarrhea and intestinal atrophy were similar between icPC22A and the coinfection groups, but were significantly higher than icPC22A-S1Δ197 group. In Vero and IPEC-DQ cells, certain concentrations of BM, PGM, bile and bile acids increased significantly the infectivity of icPC22A but had no or negative effects on icPC22A-S1Δ197. These results indicated that the replication of the S-intact PEDV was enhanced during coinfection in piglets. This observation may be explained partially by the fact that mucin, bile and bile acids in gastrointestinal tract had facilitating effects on the infection of S-intact PEDV, but no/inhibition effects on S1 NTD-del PEDV.

Molecular evolution of porcine epidemic diarrhea virus and porcine deltacoronavirus strains in Central China.

Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) are epizootic swine viruses. To detect and study the evolution of PEDV and PDCoV in central China (Shanxi, Henan, Hubei province), 70 clinical intestinal and fecal samples from piglets with severe watery diarrhea during August 2015 and June 2016 were collected, tested and analyzed. PEDV was more frequently detected by PCR than PDCoV. Phylogenetic analysis of S genes showed that the 10 PEDV strains from this study clustered into G2a (n = 7) and G2b (n = 3) groups. Additionally, the three G2b strains (PEDV S2△) contained the same specific 3 nt deletion in S2 as other reference strains in G2b. Interestingly, complete genome analysis indicated that CH/hubei/2016 was closer to the US INDEL strain and G2a group. CH/hubei/2016 had one recombination event in S2 gene which may have resulted from AH2012-12 (from G2b group) and CH-ZMDZY-11 (from G2a group). Furthermore, 10 purifying selection sites in S gene indicated an adaptive evolution of PEDV in central China swine herds. These results suggested that Pandemic G2a and G2b are predominant PEDV genotype circulating in central China. In addition, the deletion and recombination identified in S gene suggested PEDV strains of central exhibited an evolutionary variety. However, whether these changes affect the pathogenicity and antigenicity of wild PEDV is unknown and is worth for further investigation.

New variants of porcine epidemic diarrhea virus with large deletions in the spike protein, identified in the United States, 2016-2017.

Four types of porcine epidemic diarrhea virus (PEDV) variants with a large deletion in the spike protein were detected, together with the original US PEDV, from pig fecal and oral fluid samples collected during 2016-2017 in the US. Two of the variants are similar to those identified in Japan: one contains a 194-aa deletion, the same as PEDV variant TTR-2/JPN/2014, while the other contains a 204-aa deletion, the same as PEDV variant JKa-292/CS1de204. Two new S1 NTD-del PEDV variants were found: one contains a 201-aa deletion located at residues 30-230 and the other contains a 202-aa deletion located at residues 24-225 of the S protein. This is the first report on coinfection of S1 NTD-del PEDV variants and the original US PEDV strain in US pigs, indicating that PEDV continues to evolve in pigs and might be responsible for disease pattern changes.

A novel duplex TaqMan probe-based real-time RT-qPCR for detecting and differentiating classical and variant porcine epidemic diarrhea viruses.

Two different genotypes of porcine epidemic diarrhea virus (PEDV), the classical and variant strains, are classified by multiple insertions and deletions in their S genes. It is critical to detect and differentiate two genotypes in the pork industry to prevent PEDV outbreaks. In the present study, a novel duplex TaqMan RT-PCR was developed for detecting and differentiating PEDV strains in China. There was no cross-amplification between the two probes when using standard recombinant plasmids, and the specificity was further confirmed by using other seven non-PEDV swine pathogens. The minimum copies required for the detection of both classical and variant PEDV were 4.8 × 102 DNA copies/reaction. The repeatability of TaqMan RT-PCR was evaluated using standard recombinant plasmids and gave coefficients of variation 0.19-4.93. In recent 5 years, 79 clinical samples were collected from piglets with severe diarrhea in the Central China. Among these clinical samples, 51 were confirmed as PEDV positive by conventional RT-PCR, whereas 63 variant PEDV, 3 co-infections and 1 classical PEDV were confirmed by this duplex TaqMan RT-PCR, with viral loads of 102-108, 102-103, and 104 copies/reaction, respectively. Therefore, the duplex TaqMan RT-PCR could be a useful method for detecting and differentiating variant and classical PEDV strains. The results showed that variant PEDV was prevalent in clinical samples in central China. Moreover, in this study, co-infection by PEDV strains was detected for the first time and might help explain the emergence of the novel recombinant PEDV in recent years.

Detection and phylogenetic analysis of porcine epidemic diarrhea virus in central China based on the ORF3 gene and the S1 gene.

BACKGROUND: Porcine epidemic diarrhea (PED) has increased in severity in China since 2010. To investigate further the infectivity, genetic diversity and molecular epidemiology of its causative agent, the porcine epidemic diarrhea virus (PEDV), we assessed 129 clinical samples, which were the intestinal tissue of piglets with severe diarrhea, from 17 cities in central China. Both the spike (S) glycoprotein (S1, 1-789 amino acids (aa)) and the full-length ORF3 gene of 21 representative field strains from 21 farms in 11 cities were sequenced and analysed. METHODS: PEDV was detected by reverse transcription-polymerase chain reaction (RT-PCR), and S1 and ORF3 sequences were processed by the Clustal W method via DNAMAN 8 software, and phylogenetic trees were constructed by the neighbor-joining method using MEGA 6 software. RESULTS: The prevalence of PEDV was 92.25% and was detected in 119 of 129 samples, with 94.03% (63 of 67) of pig farms harbouring the disease. According to the phylogenetic analysis of the S1 genes, our isolates all fell into group G2 (variants) and showed a close relationship to isolates from Chinese (HN1303, CH/ZMDZY/11 and AJ1102), Korean (AD01), American (MN, IA1, IA2 and 13-019349) sources, and these isolates differed genetically from other Chinese (LZC, CH/HNZZ/2011 and SD-M) and Korean (SM98) strains as well Japanese (83-P5 and MK) strains. In addition, our isolates differed from attenuated vaccine strains, CV777 (used in China) and DR13 (used in Korea). According to our derived amino acid sequence analysis, we detected one novel variant PEDV, viz: CH/HNLY, with 4-aa insertion/deletion (RSSS/T) at position 375 and 1-aa (D) deletion at position 430 compared to the CV777 attenuated strain. These mutations were located on the receptor binding domain. Our ORF3 gene analyses showed that the prevalent PEDV isolates were variants, and the isolated strains differed genetically from the vaccine strains. CONCLUSIONS: These findings illustrated the existence of genetic diversity among geographically distinct PEDV strains, and our study has provided an impetus to conduct further research on the PEDV receptor binding protein and on the new and efficacious vaccines design.

Cloning and Characterization of the IgA Fc Receptor from Swine.

The myeloid-specific IgA Fc receptor (FcαR) is a cell surface molecule on immunocytes that provides a fundamental connection between humoral and cellular immunity. In this study, the full-length cDNA sequence of swine FcαRI (swFcαRI) was isolated and characterized and found to contain a 792-base-pair open reading frame, encoding a 264-amino-acid transmembrane glycoprotein with a predicted molecular mass of 29.4 kDa. The swFcαRI shares high amino acid sequence homology (>50%) with its counterparts from cattle, seal, and horse. Rosetting analysis confirmed that COS-7 cells transfected with an swFcαRI expression plasmid was able to combine with chicken erythrocytes sensitized with porcine IgA, but not IgG.

High level soluble expression and one-step purification of IBDV VP2 protein in Escherichia coli.

OBJECTIVES: To improve the expression of soluble IBDV VP2 protein by using different tagged vectors in Escherichia coli. RESULTS: Fusion tags, Grifin, MBP, SUMO, thioredoxin, γ-crystallin, ArsC and PpiB, enhanced the expression and solubility of VP2 protein. The fusion proteins were purified by Ni-NTA chromatography, MBP-VP2 showed the highest purity about 90 %. After removing the MBP tag, VP2 self-assembled into virus-like particles, ~25 nm diam. Results from AGP suggested the recombinant IBDV VP2 protein identified by reference serum like IBDV. CONCLUSION: All the seven tags enhanced the expression and solubility of IBDV VP2 protein. The recombinant protein self-assembly into virus like particles and possess antigenicity as reference IBDV.

Phylogenetic analysis of porcine epidemic diarrhea virus (PEDV) field strains in central China based on the ORF3 gene and the main neutralization epitopes.

Since 2010, porcine epidemic diarrhea has re-emerged with devastating impact on the swine-raising industry in central China. To investigate the epidemic characteristics of PEDV, the complete ORF3 genes of 14 PEDV field strains from central China during 2012 to 2013 were cloned, sequenced and compared with reference strains. Phylogenetic analysis based on the complete ORF3 gene showed that the PEDVs in central China and the reference strains could be divided into three groups: G1, G2, and G3. The 14 PEDV isolates were classified as G1 and showed a close relationship to some Chinese strains isolated previously in central China and differed genetically from recent isolates from southern China, Korean strains (SM98 and DB1865, 2012), the Chinese LZC strain (2007), and the vaccine strain (CV777) being used in China. Our findings suggested that the PEDVs circulating between 2012 and 2013 in central China might have evolved from earlier strains in the local region. To determine the reason for recent vaccination failures, we also studied variations in antigenicity of field strains by analyzing the three neutralizing epitope regions in the S gene. The results showed that the neutralizing epitopes at aa 245-252 were highly conserved, but most of the amino acid changes occurred in the epitope regions aa 7-146 and 271-278. We speculate that the amino acid mutations in the neutralizing epitope regions may be associated with changes in the antigenicity of PEDV and consequently result in vaccination failure. Together, these findings may be useful for understanding the epidemiology of PEDV and may be relevant for designing of new and more efficacious vaccines.