title: Placenta growth factor and vascular endothelial growth factor a have differential, cell-type specific patterns of expression in vascular cells.
abstract: OBJECTIVE
  PLGF, a VEGF-A related protein, mediates collateral enlargement via monocytes but plays little role in capillary proliferation. In contrast, VEGF-A mediates both collateral enlargement and capillary proliferation. PLGF has been less thoroughly studied than VEGF-A, and questions remain regarding its regulation and function. Therefore, our goal was to characterize the expression of PLGF by vascular cells. We hypothesized that vascular SMC would express more PLGF than EC, since VEGF-A is primarily expressed by non-EC.
  
  
  METHODS
  We compared PLGF and VEGF-A across eight EC and SMC lines, then knocked down PLGF and evaluated cell function. We also assessed the effect of hypoxia on PLGF expression and promoter activity.
  
  
  RESULTS
  PLGF was most highly expressed in EC, whereas VEGF-A was most highly expressed in SMC. PLGF knockdown did not affect EC number, migration, or tube formation, but reduced monocyte migration toward EC. Monocyte migration was rescued by exogenous PLGF. Hypoxia increased PLGF protein without activating PLGF gene transcription.
  
  
  CONCLUSIONS
  PLGF and VEGF-A have distinct patterns of expression in vascular cells. EC derived PLGF may function primarily in communication between EC and circulating cells. Hypoxia increases EC PLGF expression posttranscriptionally.
authors.affiliation: Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma, USA.
authors.forename: Lingjin
authors.initials: L
authors.lastname: Xiang
authors.forename: Rohan
authors.initials: R
authors.lastname: Varshney
authors.forename: Nabil A
authors.initials: NA
authors.lastname: Rashdan
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Shaw
authors.forename: Pamela G
authors.initials: PG
authors.lastname: Lloyd
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D009000:Monocytes / Q000166:cytology / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism*; D009928:Organ Specificity; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000096:biosynthesis*; D013552:Swine; D020298:U937 Cells; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*
chemical_list: C000608036:PGF protein, human; D011257:Pregnancy Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000072483:Placenta Growth Factor
keywords: arteriogenesis; endothelial cells; growth factors; vascular smooth muscle cells