Expression of parathyroid hormone-related peptide and its receptor messenger ribonucleic acid in human amnion and chorion-decidua: implications for secretion and function.
OBJECTIVE
Our purpose was to define the location and packaging of parathyroid hormone-related peptide in amnion-chorion and the potential target tissues for its action in fetal membranes.


METHODS
We studied fetal membranes by use of light microscopic immunocytochemistry with three monoclonal antibodies against distinct regions of the parathyroid hormone-related peptide molecule. For electron microscopy immunogold analysis with a monoclonal antibody specific to the 109-141 fragment was used to observe parathyroid hormone-related peptide intracellularly in amnion membrane and in the chorion layers. Multiplex reverse transcriptase-polymerase chain reaction with Southern blotting was used to identify parathyroid hormone/parathyroid hormone-related peptide receptor and control messenger ribonucleic acids in amnion and chorion-decidua.


RESULTS
All monoclonal antibodies revealed immunoreactive parathyroid hormone-related peptide in the amniotic epithelial cells and in some fibroblast-like cells embedded in the extracellular matrix of the amnion. Parathyroid hormone-related peptide was also found in the chorion in fibroblast and trophoblast layers and in decidua. Ultrastructurally immunogold particles were evenly distributed throughout the amniotic epithelial cells and were present in apical microvilli and near the basal membranes. Electron microscopy studies of the chorion cytotrophoblast also showed freely dispersed immunogold particles of parathyroid hormone-related peptide with no packaging in secretory granules. Low to undetectable levels of parathyroid hormone/parathyroid hormone-related peptide receptor messenger ribonucleic acid were found in amnion tissue, whereas abundant receptor messenger ribonucleic acid was found in chorion-decidua.


CONCLUSIONS
These results suggest the presence of a parathyroid hormone-related peptide paracrine system within the human fetal membranes.
Bruns
M E
ME
Department of Pathology, University of Virginia, Charlottesville, USA.
Ferguson
J E
JE
Bruns
D E
DE
Burton
D W
DW
Brandt
D W
DW
Jüppner
H
H
Segre
G V
GV
Deftos
L J
LJ
D000650:Amnion / Q000737:chemistry* / Q000648:ultrastructure; D002823:Chorion / Q000737:chemistry* / Q000648:ultrastructure; D003656:Decidua / Q000737:chemistry* / Q000648:ultrastructure; D004848:Epithelium / Q000737:chemistry; D005109:Extracellular Matrix / Q000737:chemistry; D005260:Female; D005347:Fibroblasts / Q000737:chemistry; D006801:Humans; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008871:Microvilli / Q000737:chemistry; D044162:Parathyroid Hormone-Related Protein; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011506:Proteins / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis*; D044168:Receptor, Parathyroid Hormone, Type 1; D018016:Receptors, Parathyroid Hormone / Q000235:genetics*
C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D012333:RNA, Messenger; D044168:Receptor, Parathyroid Hormone, Type 1; D018016:Receptors, Parathyroid Hormone