Folate transporter expression in placenta from pregnancies complicated with birth defects.

BACKGROUND: Folate plays a fundamental role for fetal development, participating in cell division, embryogenesis, and fetal growth. The fetus depends on maternal supply of folate across the placenta. The objective of this study was to compare the expression of Folate Receptor-α (FR-α), Reduced Folate Carrier (RFC), and Proton Coupled Folate Transporter (PCFT) in placentas from pregnancies complicated with birth defects (BD) and controls. METHODS: Case-control study, including placentas of BD-complicated pregnancies (n = 25) and a control group (n = 25). We determined the placental expression of FR-α, RFC, and PCFT by immunohistochemistry. Optical density was measured to obtain a relative quantification of the expression. RESULTS: The expression of PCFT was greater in placentas from pregnancies complicated with BD than in those from the control group (p < .01). The expression of FR-α and RFC was not different between groups. CONCLUSION: The expression of PCFT in placentas from BD-complicated pregnancies is increased, possibly as an adaptive response to increase the folate flux at the maternal-fetal interface.

Mechanistic insights of intestinal absorption and renal conservation of folate in chronic alcoholism.

Folate mediated one-carbon metabolism is of fundamental importance for various cellular processes, including DNA synthesis and methylation of biological molecules. Due to the exogenous requirement of folate in mammals, there exists a well developed epithelial folate transport system for regulation of normal folate homeostasis. The intestinal and renal folate uptake is tightly and diversely regulated and disturbances in folate homeostasis like in alcoholism have pathological consequences. The study was sought to delineate the regulatory mechanism of folate uptake in intestine and reabsorption in renal tubular cells that could evaluate insights of malabsorption during alcoholism. The folate transporters PCFT and RFC were found to be associated with lipid rafts of membrane surfaces in intestine and kidney. Importantly, the observed lower intestinal and renal folate uptake was associated with decreased levels of folate transporter viz. PCFT and RFC in lipid rafts of intestinal and renal membrane surfaces. The decreased association of folate transporters in lipid rafts was associated with decreased protein and mRNA levels. In addition, immunohistochemical studies showed that alcoholic conditions deranged that localization of PCFT and RFC. These findings could explain the possible mechanistic insights that may result in folate malabsorption during alcoholism.