These studies suggested that PV PVH might promote
These studies suggested that PV/PVH might promote bone formation activities and/or inhibit bone resorption activities probably due to its anti-inflammation activity; however, the underlying mechanism remained unknown. Furthermore, it is unclear if PVH shows better activity than that of PV; this is important for future animal study as PVH possesses small molecular weight size and is considered have better bioavailability than that of intact protein (Ren, Li, Offengenden, & Wu, 2015). This experiment was designed to study the effects of PV and PVH on osteoblast differentiation as well as the possible mediating pathways. We were also interested to confirm whether PV/PVH show any anti-inflammation activities in TNF-ɑ induced osteoblast LY364947 mg as inflammatory cytokines/chemokines play an important role in bone remodeling.
Materials and methods
Results and discussion
Conclusions Osteoporosis is a progressive bone disease caused by an imbalance between bone formation and bone resorption. Most current therapeutic approaches target at inhibition of osteoclast-mediated bone resorption. However, osteoporosis is often coupled with diminished osteoblast activity and function; inhibition of excessive bone resorption is necessary but it is also of great importance to regain osteoblast’s function and restore bone quality, possibly by regulating osteoblasts. Given the biological function of osteoblasts, recent research attention has focused on developing anabolic drugs. Strontium ranelate and teriparatide are two anabolic drugs targeting at G protein-coupled calcium-sensing and parathyroid hormone-1 receptors to promote bone formation activities (Diepenhorst et al., 2017). PV and PVH have drawn great research interests due to their various physiological functions. PV was also reported to promote bone formation in tissue culture and PVH promoted bone mineral density in vivo (Choi et al., 2005, Liu et al., 2013). Considering oxidation and inflammation also play a role in bone loss under pathological conditions, PV/PVH are promising candidates with bone formation promoting ability.
Declarations of interest
Acknowledgements This research was funded by grants from Alberta Agriculture and Forestry, Egg Farmers of Canada, Michael Foods Ltd., and the Natural Sciences and Engineering Research Council (NSERC) of Canada to J. Wu. The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript.
Introduction The hexameric DNA helicase E1 is the only enzyme and the most conserved protein encoded by papillomaviruses (PVs). This high degree of conservation reflects the essential role that E1 plays during the viral life cycle, namely as the replicative helicase that orchestrates the faithful copying of the viral episome in the nucleus of infected keratinocytes. E1 is thought to be required throughout the viral replicative cycle, first to increase the copy number of the viral episome upon infection of basal keratinocytes, then to maintain a constant level of episomes in cells that are displaced upward in the epithelium and begin to differentiate, and, finally, to promote amplification of the viral genome during the productive phase of the viral life cycle that takes place in the uppermost differentiated epithelial layers. Studies in cell culture have demonstrated that E1 is essential for establishing the viral genome as a multicopy episome in the nucleus of transfected keratinocytes, a process that is believed to mimic, albeit only partially, what happens to the viral DNA during the early stages of infection. Cell culture studies have also supported the notion that E1 is required for the amplification of the viral genome that occurs upon cellular differentiation; some of the evidence coming from the identification of E1 mutant proteins that are specifically defective for this process. However, there remains some controversy as to whether E1 is also needed to maintain the viral episome at a constant copy number in undifferentiated cells; some studies suggesting that once the viral genome has been established as a multicopy episome, its replication and maintenance in proliferating keratinocytes become E1-independent (Egawa et al., 2012, Kim and Lambert, 2002).