Vitamin D-Binding Protein is Involved in the Pathogenesis of Preeclampsia by Inhibiting the Tyrosine Phosphorylation of Vascular Endothelial Growth Factor Receptor-2 in Endothelial Cells

Objective::The role of Vitamin D-binding protein(DBP)in preeclampsia(PE)pathogenesis is unknown.In this study,we compared the expression of DBP in the placentas of PE patients with the placentas of normotensive pregnant women with placenta previa controls,and aimed to explore the effect of DBP on endothelial cells(ECs)and the underlying mechanism.Methods::DBP expression in placental tissues collected from PE patients and controls was evaluated by immunohistochemistry.The downregulation and upregulation of DBP expression in HTR-8/SVneo cells were examined using DBP-targeting small interfering RNA(siRNA)and DBP-expression vector,respectively.The conditioned media of these DBP-overexpressing and DBP-siRNA HTR-8/SVneo cells were collected and added to human umbilical vein EC(HUVEC)cultures.Angiogenic effects on HUVECs were assessed by tube formation assays,and the proliferation and migration of HUVECs were examined using the Real-Time Cell Analyzer.The expression of vascular endothelial growth factor(VEGF)and VEGF receptor(VEGFR)-2,as well as the phosphorylation of different residues of VEGFR-2 in HUVECs,were determined by western blotting.Results::DBP expression was significantly increased in the placental tissues collected from PE patients.The conditioned medium of DBP-overexpressing HTR-8/SVneo cells potently inhibited tube formation by HUVECs,in addition to their proliferation and migration.Furthermore,treatment of HUVECs with the conditioned medium of DBP-overexpressing HTR-8/SVneo cells decreased the phosphorylation of VEGFR-2 at tyrosine 996,whereas the treatment of these cells with the conditioned medium of DBP-siRNA HTR-8/SVneo cells increased the phosphorylation of VEGFR-2 at tyrosine 951,996,and 1,175.Conclusions::The expression of DBP is increased in the placentas of PE patients.DBP plays potential roles in endothelial dysfunction,which contributes to PE development,by inhibiting tyrosine phosphorylation of VEGFR-2 in ECs.

Draft Genome of White-blotched River Stingray Provides Novel Clues for Niche Adaptation and Skeleton Formation

The white-blotched river stingray(Potamotrygon leopoldi)is a cartilaginous fish native to the Xingu River,a tributary of the Amazon River system.As a rare freshwater-dwelling cartilaginous fish in the Potamotrygonidae family in which no member has the genome sequencing information available,P.leopoldi provides the evolutionary details in fish phylogeny,niche adaptation,and skeleton formation.In this study,we present its draft genome of 4.11 Gb comprising 16,227 contigs and 13,238 scaffolds,with contig N50 of 3937 kb and scaffold N50 of 5675 kb in size.Our analysis shows that P.leopoldi is a slow-evolving fish that diverged from elephant sharks about 96 million years ago.Moreover,two gene families related to the immune system(immunoglobulin heavy constant delta genes and T-cell receptor alpha/delta variable genes)exhibit expansion in P.leopoldi only.We also identified the Hox gene clusters in P.leopoldi and discovered that seven Hox genes shared by five representative fish species are missing in P.leopoldi.The RNA sequencing data from P.leopoldi and other three fish species demonstrate that fishes have a more diversified tissue expression spectrum when compared to mammals.Our functional studies suggest that lack of the gc gene encoding vitamin D-binding protein in cartilaginous fishes(both P.leopoldi and Callorhinchus milii)could partly explain the absence of hard bone in their endoskeleton.Overall,this genome resource provides new insights into the niche adaptation,body plan,and skeleton formation of P.leopoldi,as well as the genome evolution in cartilaginous fishes.