Proteomic and phosphoproteomic analyses reveal several events involved in the early stages of bovine herpesvirus 1 infection.

Herpesviruses are predicted to express more than 80 proteins during their infection cycle. The proteins synthesized by the immediate early genes and early genes target signaling pathways in host cells that are essential for the successful initiation of a productive infection and for latency. In this study, proteomic and phosphoproteomic tools showed the occurrence of changes in Madin-Darby bovine kidney cells at the early stage of the infection by bovine herpesvirus 1 (BoHV-1). Proteins that had already been described in the early stage of infection for other herpesviruses but not for BoHV-1 were found. For example, stathmin phosphorylation at the initial stage of infection is described for the first time. In addition, two proteins that had not been described yet in the early stages of herpesvirus infections in general were ribonuclease/angiogenin inhibitor and Rab GDP dissociation inhibitor beta. The biological processes involved in these cellular responses were repair and replication of DNA, splicing, microtubule dynamics, and inflammatory responses. These results reveal pathways that might be used as targets for designing antiviral molecules against BoHV-1 infection.

Improved vascularisation but inefficient in vivo bone regeneration of adipose stem cells and poly-3-hydroxybutyrate-co-3-hydroxyvalerate scaffolds in xeno-free conditions.

Bone defects are a common clinical situation. However, bone regeneration remains a challenge and faces the limitation of poor engraftment due to deficient vascularisation. Poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHB-HV) and human adipose stem cells (hASC) are promising for vascularisation and bone regeneration. Therefore, we sought to investigate the bone regenerative capacity of hASCs cultured in allogeneic human serum (aHS) and PHB-HV scaffolds in a nude mouse model of the critical-sized calvarial defect. We evaluated bone healing for three treatment groups: empty (control), PHB-HV and PHB-HV + hASCs. The pre-implant analysis showed that hASCs colonised the PHB-HV scaffolds maintaining cell viability before implantation. Histological analysis revealed that PHB-HV scaffolds were tolerated in vivo; they integrated with adjacent tissue eliciting a response like a foreign body reaction, and tiny primary bone was observed only in the PHB-HV group. Also, the µ-CT analysis revealed only approximately 10% of new bone in the bone defect area in both the PHB-HV and PHB-HV + hASCs groups. The expression of BGLAP and its protein (osteocalcin) by PHB-HV + hASCs group and native bone was similar while the other bone markers RUNX2, ALPL and COL1A1 were upregulated, but this expression remained significantly lower compared to the native bone. Nevertheless, the PHB-HV group showed neovascularisation at 12 weeks post-implantation while PHB-HV + hASCs group also exhibited higher VEGFA expression as well as a higher number of vessels at 4 weeks post-implantation, and, consequently, earlier neovascularisation. This neovascularisation must be due to scaffold architecture, improved by hASCs, that survived for the long term in vivo in the PHB-HV + hASCs group. These results demonstrated that hASCs cultured in aHS combined with PHB-HV scaffolds were ineffective to promote bone regeneration, although the construct of hASCs + PHB-HV in xeno-free conditions improved scaffold vascularisation representing a strategy potentially promising for other tissue engineering applications.