Expression of peroxisome proliferator-activated receptor gamma (PPARgamma) in normal human pancreatic islet cells.
OBJECTIVE
Thiazolidinediones are reported to improve pancreatic islet morphology and beta-cell function in rodents, supporting the hypothesis of a direct action of thiazolidinediones on endocrine islet cells. In this study we examined the expression of the peroxisome proliferator-activated receptor gamma, a nuclear receptor that is activated by naturally occurring fatty acids and synthetic thiazolidinediones, in normal human endocrine pancreatic cells.


METHODS
Human islets were isolated from pancreata harvested in ten brain-dead lean non-diabetic adult donors. We analysed the gene and protein expression of the human peroxisome proliferator-activated receptor gamma and evaluated the effects of peroxisome proliferator-activated receptor gamma agonist on insulin secretion in human islet preparations.


RESULTS
The RT-PCR carried out on total RNA from four distinct human islet preparations demonstrated the presence of peroxisome proliferator-activated receptor gamma mRNA. Western blot analysis showed the consistent expression of peroxisome proliferator-activated receptor gamma protein. Peroxisome proliferator-activated receptor gamma was shown to be present in all three endocrine cell types studied (alpha, beta and delta cells) by immunohistochemistry.


CONCLUSIONS
We found that peroxisome proliferator-activated receptor gamma is highly expressed in human islet endocrine cells, both at the mRNA and protein levels. These results support the hypothesis of a direct influence of peroxisome proliferator-activated receptor gamma agonist on human pancreatic endocrine cells.
Dubois
M
M
UPRES 1048, University Hospital Centre of Lille, France.
Pattou
F
F
Kerr-Conte
J
J
Gmyr
V
V
Vandewalle
B
B
Desreumaux
P
P
Auwerx
J
J
Schoonjans
K
K
Lefebvre
J
J
D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism; D000328:Adult; D004268:DNA-Binding Proteins / Q000235:genetics; D005934:Glucagon / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000032:analysis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013004:Somatostatin / Q000032:analysis; D014157:Transcription Factors / Q000032:analysis / Q000235:genetics*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D007328:Insulin; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D013004:Somatostatin; D005934:Glucagon