Effects of leptin on the expression of fatty acid-binding proteins in human placental cell cultures
The present study aimed to evaluate the protein expression of the transmembrane translocase FAT/CD36 and cytoplasmic H-FABP and L-FABP in human trophoblast tissue and evaluate the effects of exogenous leptin upon differential expression of each biomolecule; consequently, it aimed to derive information regarding the effects of leptin upon the expression of proteins implicated in fatty acid metabolism. Protein and total RNA were isolated from 72 samples of trophoblast tissue obtained from chorionic villous sampling. Of these, 36 samples were evaluated for protein (supernatant and pellet fraction separated) and the other 36 for total RNA expression. For each subgroup of samples, 12 were treated immediately and 24 were cultured. Half of the cultured samples were treated with 10 ng/ml exogenously added leptin and the other half were untreated. Western blotting and PCR techniques were used for the evaluation of biomolecule expression. Our results were obtained from samples at a mean gestational week of 12(+5) (n=72; min, 11(+0); max, 14(+1) gw; SD,0.89). In promptly treated samples we observed the presence of FAT/CD36 protein and absence of cytoplasmic FABPs. In the latter, only mRNA transcription of H-FABP was noted. A cytoplasmic pool of FAT/CD36 was also noted in the supernatant fraction of proteins. For cultured samples, when leptin was added, a statistically significant increase in FAT/CD36 protein expression was observed (n=24, p<0.001; mean difference, 0.219; SD, 0.0315; CI, -0.284 to -0.154). In our study we demonstrated the protein and m RNA expression of biomolecules implicated in fatty acid metabolism in human placenta. A cytoplasmic pool of the transmembrane protein FAT/CD36 was noted. Leptin caused the increase in FAT/CD36 protein expression in the cultured samples. Therefore, we conclude that leptin has an immediate effect and plays a role in lipid metabolism in human placenta.