Background: Porcine epidemic diarrhea virus (PEDV), an enteric coronavirus, has become the major causative agent of acute gastroenteritis in piglets since 2010 in China.Results: In the current study, 91 complete spike (S) gene sequences were obtained from PEDV positive samples collected from 17 provinces in China from March 2020 to March 2021. A phylogenetic analysis showed that 92.3% (84 out of 91) of the identified strains belonged to GII subtype, while 7.7% (7 out of 91) were categorized as S-INDEL like strains and grouped within GI-c clade. Based on a recombination analysis, six of S-INDEL like strains were recombinant strains originated from S-INDEL strain FR/001/2014 and virulent strain AJ1102. In addition, PEDV variant strains (CH/GDMM/202012, CH/GXDX/202010 et al) carrying novel insertions (360QGRKS364 and 1278VDVF1281) in the S protein were observed. Furthermore, the deduced amino acid sequences for the S protein showed that multiple amino acid substitutions in the antigenic epitopes in comparison with the vaccine strains.Conclusions: In conclusion, these data provide novel molecular evidence on the epidemiology and molecular diversity of PEDV in 2020–2021. This information may help design a strategy for controlling and preventing the prevalence of PEDV variant strains in China.

Staphylococcal enterotoxin-like K (SEl-K) is a potent mitogen that elicits T-cell proliferation and cytokine production at very low concentrations. However, unlike the classical enterotoxins SEB and toxic shock syndrome toxin 1 (TSST-1), the gene for SEl-K is commonly present in more than half of all Staphylococcus aureus clinical isolates and is present in almost all USA300 community-acquired methicillin-resistant S. aureus (CA-MRSA) isolates. Sequencing of the sel-k gene in over 20 clinical isolates and comparative analysis with all 14 published sel-k sequences indicate that there are at least 6 variants of the sel-k gene, including one that is conserved among all examined USA300 strains. Additionally, we have developed a highly sensitive enzyme-linked immunosorbent assay (ELISA) that specifically detects and measures SEl-K protein in culture supernatants and biological fluids. Quantification of in vitro SEl-K secretion by various S. aureus isolates using this novel capture ELISA revealed detectable amounts of SEl-K secretion by all isolates, with the highest secretion levels being exhibited by MRSA strains that coexpress SEB. In vivo secretion was measured in a murine thigh abscess model, where similar levels of SEl-K accumulation were noted regardless of whether the infecting strain exhibited high or low secretion of SEl-K in vitro . We conclude that SEl-K is commonly expressed in the setting of staphylococcal infection, in significant amounts. SEl-K should be further explored as a target for passive immunotherapy against complicated S. aureus infection.

Hepatocellular carcinoma (HCC) is an aggressive malignancy with poor prognosis. LncRNA MAPKAPK5-AS1 is a potential oncogene and contributes to HCC cell malignant proliferation. This study explores the role of MAPKAPK5-AS1 carried by carcinoma-associated fibroblasts-derived extracellular vesicles (CAF-EVs) in HCC cell proliferation. Our findings reveal that CAF-EVs promotes HCC cell proliferation by delivering MAPKAPK5-AS1, which binds to and inhibits SMURF2 and stabilizes TCF12. SMURF2 leads to TCF12 ubiquitination and degradation. TCF12 upregulates FOXH1 expression. In animal model, CAF-EVs enhances tumor growth by stabilizing TCF12 via MAPKAPK5-AS1 and activating FOXH1 transcription. In conclusion, CAF-EVs carrying MAPKAPK5-AS1 stabilizes TCF12 expression by competitively inhibiting SMURF2, thus promoting TCF12-mediated FOXH1 transcription and driving HCC cell proliferation. Our findings may offer insights for HCC treatment and suggest potential targets for future treatments, opening avenues for HCC therapies.