A Common Variant of PROK1 (V67I) Acts as a Genetic Modifier in Early Human Pregnancy through Down-Regulation of Gene Expression

Abstract

PROK1-V67I has been shown to play a role as a modifier gene in the PROK1-PROKR system of human early pregnancy. To explore the related modifier mechanism of PROK1-V67I, we carried out a comparison study at the gene expression level and the cell function alternation of V67I, and its wild-type (WT), in transiently-transfected cells. We, respectively, performed quantitative RT-PCR and ELISA assays to evaluate the protein and/or transcript level of V67I and WT in HTR-8/SV neo, JAR, Ishikawa, and HEK293 cells. Transiently V67I- or WT-transfected HTR-8/SV neo and HEK293 cells were used to investigate cell function alternations. The transcript and protein expressions were down-regulated in all cell lines, ranging from 20% to 70%, compared with WT. There were no significant differences in the ligand activities of V67I and WT with regard to cell proliferation, cell invasion, calcium influx, and tubal formation. Both PROK1 alleles promoted cell invasion and intracellular calcium mobilization, whereas they had no significant effects on cell proliferation and tubal formation. In conclusion, the biological effects of PROK1-V67I on cell functions are similar to those of WT, and the common variant of V67I may act as a modifier in the PROK1-PROKR system through down-regulation of PROK1 expression. This study may provide a general mechanism that the common variant of V67I, modifying the disease severity of PROK1-related pathophysiologies.

Primary Cilium‐Regulated EG‐VEGF Signaling Facilitates Trophoblast Invasion

“…The ectopic expression of EG‐VEGF was induced through transient transfection of HTR‐8/SVneo cells, as described previously (Su et al, ). The EG‐VEGF plasmid, containing Myc‐DDK‐tagged cDNA in a pCMV6‐Entry vector, includes the entire coding region of human EG‐VEGF cDNA (GenBank NM_032414.2) and was purchased from OriGene Technologies (Rockville, MD).…”

Endocrine Gland-Derived Vascular Endothelial Growth Factor/Prokineticin-1 in Cancer Development and Tumor Angiogenesis

“…Thus, EG-VEGF is considered to be the human orthologue of VPRA. Other members of this family include Bv8 [14], the secreted protein from the frog Bombina variegata , its mammalian orthologues [15, 16]. Also included herein is the digestive enzyme colipase [13] and the protein Dickkopf [3, 17, 18], which is an inhibitor of Wnt signaling.…”

“…The same authors stated that, because its regulation by hypoxia and its complementary expression localisation to that of VEGF, EG-VEGF is involved in the pre-eclampsia pathogenesis. Recently published papers gave new insights into the EG-VEGF involvement in normal and pathological placental angiogenesis [12] and, maybe more important, its dysregulations impeding trophoblast proliferation and its decidual invasion [14] or pregnancy loss [15]. Also, the expression of both factors, VEGF and EG-VEGF, was identified in adrenal carcinomas.…”

“…EG-VEGF (also known as prokineticin-1) and prokineticin-2 act on 2 receptors, namely, PROKR1 and PROKR2 [14, 25, 26]. Receptor activation stimulates intracellular calcium levels, the turnover of phosphoinositide and the induction of mitogen-activated protein kinase (MAPK).…”

Identifying Genetic Modifiers in the Age of Exome: Current Considerations

“…6 A second concern is the restriction to rare variants deemed as pathogenic. This is problematic, because the investigators are searching for modifier loci which may be the result of common genetic variants 7,8 in regulatory rather than protein coding genes. [9][10][11] The investigators ignore the contribution of common variation.…”