title: The role of the carbohydrate recognition domain of placental protein 13 (PP13) in pregnancy evaluated with recombinant PP13 and the DelT221 PP13 variant.
abstract: BACKGROUND
  Placental protein 13 (PP13), a placenta specific protein, is reduced in the first trimester of pregnancy in women who subsequently develop preeclampsia. A naturally occurring PP13 deletion of thymidine at position 221 (DelT221 or truncated variant) is associated with increased frequency of severe preeclampsia. In this study we compared the full length (wildtype) PP13 and the truncated variant.
  
  
  METHODS
  Full length PP13 or its DelT221 variant were cloned, expressed and purified from E-Coli. Both variants were administrated into pregnant rats at day 8 of pregnancy for slow release (>5 days) through osmotic pumps and rat blood pressure was measured. Animals were sacrificed at day 15 or day 21 and their utero-placental vasculature was examined.
  
  
  RESULTS
  The DelT221 variant (11 kDA) lacked exon 4 and a part of exon 3, and is short of 2 amino acids involved in the carbohydrate (CRD) binding of the wildtype (18 kDA). Unlike the wildtype PP13, purification of DelT221 variant required special refolding. PP13 specific poly- clonal antibodies recognized both PP13 and DelT221 but PP13 specific monoclonal antibodies recognized only the wildtype, indicating the loss of major epitopes. Wildtype PP13 mRNA and its respective proteins were both lower in PE patients compared to normal pregnancies. The DelT221 mutant was not found in a large Caucasian cohort. Pregnant rats exposed to wildtype or DelT221 PP13 variants had significantly lower blood pressure compared to control. The wildtype but not the DelT221 mutant caused extensive vein expansion.
  
  
  CONCLUSIONS
  This study revealed the importance of PP13 in regulating blood pressure and expanding the utero-placental vasculature in pregnant rats. PP13 mutant lacking amino acids of the PP13 CRD domain fails to cause vein expansion but did reduce blood pressure. The study provides a basis for replenishing patients at risk for preeclampsia by the full length but not the truncated PP13.
authors: Prof. Ephraim Katzir Department of Biotechnology Engineering, ORT Braude College, Karmiel, Israel.
authors: Marei
authors: M
authors: Sammar
authors: Prof. Ephraim Katzir Department of Biotechnology Engineering, ORT Braude College, Karmiel, Israel.
authors: Shahar
authors: S
authors: Nisamblatt
authors: Department of Obstetrics and Gynecology, Bnai Zion Medical Center, and Technion-Israel Institute of Technology, Haifa, Israel.
authors: Ron
authors: R
authors: Gonen
authors: Institute of Cell Biology, Histology and Embryology/Biobank Graz, Medical University of Graz, Graz, Austria.
authors: Berthold
authors: B
authors: Huppertz
authors: Faculty of Pharmaceutical Sciences, School of Health Science, University of Iceland, Reykjavik, Iceland.
authors: Sveinbjorn
authors: S
authors: Gizurarson
authors: Department of Obstetrics, Gynecology and Reproductive Sciences, University of Vermont College of Medicine, Burlington, Vermont, United States of America.
authors: George
authors: G
authors: Osol
authors: Telemarpe Ltd, Tel Aviv, and Hy-Laboratories, Rehovot, Israel.
authors: Hamutal
authors: H
authors: Meiri
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002241:Carbohydrates / Q000737:chemistry*; D003001:Cloning, Molecular; D005260:Female; D037161:Galectins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D011225:Pre-Eclampsia / Q000503:physiopathology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D002241:Carbohydrates; D037161:Galectins; C038195:LGALS13 protein, human; D011257:Pregnancy Proteins; D011994:Recombinant Proteins