Expression and secretion of the atrial natriuretic peptide in human adipose tissue and preadipocytes.
OBJECTIVE
Atrial natriuretic peptide (ANP) is a secretory hormone displaying diuretic, natriuretic, and vasorelaxant activities. Recently, its lipolytic activity has been reported. Since the expression of ANP in adipose tissue has not been documented, we used real-time reverse transcriptase polymerase chain reaction (RT-PCR) to investigate the expression of ANP in human adipose tissue and preadipocytes.


METHODS
RNA was extracted from the human adipose tissue of severely obese premenopausal women as well as from human preadipocytes. For human preadipocytes, two cell systems were investigated: the human preadipose immortalized (Chub-S7) cells, a well-characterized human preadipose cell line, and primary preadipocytes derived from the stromal vascular fraction of the human adipose tissue. We measured the mRNA of ANP, of corin (a transmembrane serine protease involved in the conversion of pro-ANP to ANP) and of uncoupling protein 2 (UCP2; a control gene known to be ubiquitously expressed). The expression of ANP was also investigated using immunofluorescence and radioimmunoassay in Chub-S7 cells and human primary preadipocytes in culture.


RESULTS
Our results indicate that ANP and corin are expressed at the mRNA level in human adipose tissue and preadipocytes. Immunofluorescence experiments demonstrated that pro-ANP was expressed in Chub-S7 cells. In addition, ANP secretion could be measured in Chub-S7 cells and human primary preadipocytes in culture. Rosiglitazone, a selective peroxisome proliferator-activated receptor type gamma (PPAR-gamma) agonist promoting adipocyte differentiation, was found to modulate both ANP expression and secretion in preadipocytes.


CONCLUSIONS
Our findings suggest the existence of an autocrine/paracrine system for ANP in the human adipose tissue whose implications in lipolysis and cardiovascular function need to be further explored.
Garruti
Gabriella
G
Department of Pharmacology and Toxicology, Faculty of Biology and Medicine, University of Lausanne, Rue du Bugnon 27, CH-1005 Lausanne, Switzerland.
Giusti
Vittorio
V
Nussberger
Jürg
J
Darimont
Christian
C
Verdumo
Chantal
C
Amstutz
Catherine
C
Puglisi
Francesco
F
Giorgino
Francesco
F
Giorgino
Riccardo
R
Cotecchia
Susanna
S
D017667:Adipocytes / Q000378:metabolism*; D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D002460:Cell Line; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007473:Ion Channels / Q000737:chemistry; D008856:Microscopy, Fluorescence; D024101:Mitochondrial Proteins / Q000737:chemistry; D047495:PPAR gamma / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077154:Rosiglitazone; D012697:Serine Endopeptidases / Q000378:metabolism; D045162:Thiazolidinediones / Q000494:pharmacology; D000071256:Uncoupling Protein 1
D007473:Ion Channels; D024101:Mitochondrial Proteins; D047495:PPAR gamma; D010455:Peptides; D045162:Thiazolidinediones; D000071256:Uncoupling Protein 1; D000077154:Rosiglitazone; D012313:RNA; D009320:Atrial Natriuretic Factor; C119812:CORIN protein, human; D012697:Serine Endopeptidases