Identification of a novel linear B-cell epitope in porcine deltacoronavirus nucleocapsid protein.

Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus that caused diarrhea and/or vomiting in neonatal piglets worldwide. Coronaviruses nucleocapsid (N) protein is the most conserved structural protein for viral replication and possesses good antigenicity. In this study, three monoclonal antibodies (mAbs), 3B4, 4D3, and 4E3 identified as subclass IgG2aκ were prepared using the lymphocytic hybridoma technology against PDCoV N protein. Furthermore, the B-cell epitope recognized by mAb 4D3 was mapped by dozens of overlapping truncated recombinant proteins based on the western blotting. The polypeptide 28QFRGNGVPLNSAIKPVE44 (EP-4D3) in the N-terminal of PDCoV N protein was identified as the minimal linear epitope for binding mAb 4D3. And the EP-4D3 epitope's amino acid sequence homology study revealed that PDCoV strains are substantially conserved, with the exception of the Alanine43 substitution Valine43 in the China lineage, the Early China lineage, and the Thailand, Vietnam, and Laos lineage. The epitope sequences shared high similarity (94.1%) with porcine coronavirus HKU15-155 (PorCoV HKU15), Asian leopard cats coronavirus (ALCCoV), sparrow coronavirus HKU17 (SpCoV HKU17), and sparrow deltacoronavirus. In contrast, the epitope sequences shared a very low homology (11.8 to 29.4%) with other porcine CoVs (PEDV, TGEV, PRCV, SADS-CoV, PHEV). Overall, the study will enrich the biological function of PDCoV N protein and provide foundational data for further development of diagnostic applications. KEY POINTS: • Three monoclonal antibodies against PDCoV N protein were prepared. • Discovery of a novel B-cell liner epitope (28QFRGNGVPLNSAIKPVE44) of PDCoV N protein. • The epitope EP-4D3 was conserved among PDCoV strains.

Comprehensive codon usage analysis of porcine deltacoronavirus.

Porcine deltacoronavirus (PDCoV) is a newly identified coronavirus of pigs that was first reported in Hong Kong in 2012. Since then, many PDCoV isolates have been identified worldwide. In this study, we analyzed the codon usage pattern of the S gene using complete coding sequences and complete PDCoV genomes to gain a deeper understanding of their genetic relationships and evolutionary history. We found that during evolution three groups evolved with a relatively low codon usage bias (effective number of codons (ENC) of 52). The factors driving bias were complex. However, the primary element influencing the codon bias of PDCoVs was natural selection. Our results revealed that different natural environments may have a significant impact on the genetic characteristics of the strains. In the future, more epidemiological surveys are required to examine the factors that resulted in the emergence and outbreak of this virus.

Comparison of ß-Amyloid Plaque Labeling Methods: Antibody Staining, Gallyas Silver Staining, and Thioflavin-S Staining.

Objective To evaluate senile plaque formation and compare the sensitivity of three different ß-amyloid (Aß) labeling methods (antibody staining, Gallyas silver staining, and thioflavin-S staining) to detect Aß deposition.Methods APPswe/PSEN1dE9 transgenic mice (APP/PS1) of different ages were used to examine spatiotemporal changes in Aß plaque deposition. Antibody staining, Gallyas silver staining, and thioflavin-S staining were used to detect Aß plaque deposition in the same brain region of adjacent slices from model mice, and the results were compared.Results With aging, Aß plaques first appeared in the cortex and then the deposition increased throughout the whole brain. Significantly greater plaque deposition was detected by 6E10 antibody than that analyzed with Gallyas silver staining or thioflavin-S staining (P<0.05). Plaque deposition did not show significant difference between the APP/PS1 mice brains assayed with Gallyas silver staining and ones with thioflavin-S staining (P=0.0033).Conclusions The APP/PS1 mouse model of Alzheimer's disease could mimick the progress of Aß plaques occurred in patients with Alzheimer's disease. Antibody detection of Aß deposition may be more sensitive than chemical staining methods.

Pharmacologic inhibition of Hsp90 to prevent GLT-1 degradation as an effective therapy for epilepsy.

The glutamate transporter GLT-1 is critical for the maintenance of low interstitial glutamate concentrations. Loss of GLT-1 is commonly observed in neurological disorders, including temporal lobe epilepsy (TLE). Despite the hypothesis that targeting the mechanisms of GLT-1 deficiency may be a novel strategy for treating drug-resistant epilepsy, the underlying molecular cascade remains largely unknown. Here, we show that Hsp90ß is up-regulated in reactive astrocytes of the epileptic hippocampus in patients with TLE and mouse models of epilepsy. Inhibition of Hsp90, but not Hsp70, increased GLT-1 levels. Mechanistically, Hsp90ß recruits GLT-1 to the 20S proteasome, thereby promoting GLT-1 degradation. Hsp90 inhibitor prevents GLT-1 degradation by disrupting the association between Hsp90ß and GLT-1. Using a model of TLE, we demonstrated that long-term systemic administration of 17AAG dramatically suppressed spontaneous recurrent seizures and ameliorated astrogliosis. Overall, these results suggest that up-regulation of GLT-1 by inhibiting Hsp90ß in reactive astrocytes may be a potential therapeutic target for the treatment of epilepsy and excitotoxicity.