Comparison of the Ability of High and Low Virulence Strains of Non-cytopathic Bovine Viral Diarrhea Virus-1 to Modulate Expression of Interferon Tau Stimulated Genes in Bovine Endometrium

Characterization of a Highly Virulent Noncytopathic Bovine Viral Diarrhea Virus 2b Isolate Detected in Cattle in Inner Mongolia, China

Bovine viral diarrhea virus (BVDV) infection causes subclinical to severe acute disease in cattle all over the world. Two genotypes of BVDV are recognized, BVDV1 and BVDV2. Currently, the subtypes of BVDV1b and BVDV2a are mainly circulating in China. Here, a newly noncytopathic (ncp) BVDV strain named BVDVNM21 was isolated and identified from cattle. We determined the complete genome sequence of BVDVNM21, phylogenetic analysis of 5′ untranslated region (5′UTR), Npro, and E2 gene, and complete genome showed the virus belongs to BVDV2b subtype and formed an independent clade within BVDV2b. Genome-wide sequence analysis showed that BVDVNM21 had high homology with SD1301 (98.10%) isolated from China. In the experimental infection study of guinea pigs and calves, they all developed similar clinical signs, including a pronounced and prolonged febrile response lasting more than 3 days and pronounced reduction in white blood cells (WBC) and platelets of more than 40%. Moreover, guinea pigs showed more acute infection characteristics after infection, and WBC decreased by more than 50% at 1 day postinfection (dpi), and they recovered in less than 3 days. The results indicated that the BVDVNM21 strain showed high virulence in calves. It was the first confirmed isolation of a highly pathogenic ncpBVDV2b in cattle, as well as the establishment of the BVDV-guinea pig model. This study may provide a basis for further research and control of the prevalence of BVDV2b in China.

Mesenchymal Stem Cells in Embryo-Maternal Communication under Healthy Conditions or Viral Infections: Lessons from a Bovine Model

Bovine mesenchymal stem cells are a relevant cell population found in the maternal reproductive tract that exhibits the immunomodulation capacity required to prevent embryo rejection. The phenotypic plasticity showed by both endometrial mesenchymal stem cells (eMSC) and embryonic trophoblast through mesenchymal to epithelial transition and epithelial to mesenchymal transition, respectively, is essential for embryo implantation. Embryonic trophoblast maintains active crosstalk via EVs and soluble proteins with eMSC and peripheral blood MSC (pbMSC) to ensure the retention of eMSC in case of pregnancy and induce the chemotaxis of pbMSC, critical for successful implantation. Early pregnancy-related proteins and angiogenic markers are detected as cargo in EVs and the soluble fraction of the embryonic trophectoderm secretome. The pattern of protein secretion in trophectoderm-EVs changes depending on their epithelial or mesenchymal phenotype and due to the uptake of MSC EVs. However, the changes in this EV-mediated communication between maternal and embryonic MSC populations infected by viruses that cause abortions in cattle are poorly understood. They are critical in the investigation of reproductive viral pathologies.