In this study we describe for the first time the identification of a renal cell line that expresses the kidney-specific high-affinity H+/peptide cotransport system. The kidney cell line SKPT-0193 C1.2 was obtained by SV40 transformation of rat proximal tubular cells. The transport of the dipeptide glycylsarcosine (Gly-Sar) was studied in this cell line grown as a confluent monolayer on impermeable plastic supports. Uptake of the dipeptide was rapid and was stimulated sixfold by an inwardly directed H+ gradient, with optimal uptake occurring at an extracellular pH of 6.0. The uptake was markedly reduced by the protonophore carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone whether measured at pH 7.5 or 6.0. Intracellular acidification of the cells by NH4Cl prepulse also reduced the uptake of glycylsarcosine. The dipeptide uptake was found to be mediated by a high-affinity transport system with a Michaelis-Menten constant (Kt) of 67 +/- 2 microM and a maximal transport velocity of 1.20 +/- 0.02 nmol.10 min-1.mg protein-1. Studied over a concentration range of 5 microM to 5 mM, there was no evidence for a second saturable transport component. Di- and tripeptides, but not glycine, were strong inhibitors of glycylsarcosine uptake, indicating that these peptides also interact with the transport system with high affinity. Northern blot analysis of poly(A)+RNA from these cells using cDNA probes specific for the human intestinal peptide transporter (PEPT 1) or the human kidney-specific peptide transporter (PEPT 2) revealed that the transport system expressed in these cells is PEPT 2. It is concluded that the SKPT-0193 C1.2 cell line constitutively expresses the kidney-specific high-affinity H+/peptide cotransporter described in the proximal tubular epithelial cells of the normal kidney.
To assess the effect of lupin protein on concentrations of lipids in plasma lipoproteins and liver and hepatic mRNA concentrations of genes involved in lipid metabolism, adult rats were fed egg albumin-based diets containing either lupin protein from Lupinus albus or casein (50 g/kg) supplemented (hypercholesterolaemic) or not (normolipaemic) with a cholesterol -cholate mixture for 20 d. Lupin protein compared with casein lowered the concentrations of TAG in liver (P, 0·01) and circulating VLDL þ chylomicrons (P,0·05) of hypercholesterolaemic rats, but not of normolipaemic rats. Hepatic mRNA concentrations of genes involved in fatty acid synthesis such as sterol regulatory element-binding protein-1c, glucose-6-phosphate dehydrogenase, fatty acid synthase, stearoyl-CoA desaturase-1 and acyl-CoA:glycerol-3-phosphate acyltransferase were lower and mRNA concentrations of lipoprotein lipase, hepatic lipase and apoA5 involved in TAG hydrolysis were higher in rats fed lupin protein than in rats fed casein. These effects were stronger in hypercholesterolaemic rats than in normolipaemic rats. Hypercholesterolaemic rats fed the lupin protein had higher liver cholesterol concentrations (P, 0·01) and lower levels of LDL-cholesterol (P, 0·05) than rats fed casein. No effect of lupin protein was observed on cholesterol concentration in VLDL þ chylomicrons and HDL and hepatic mRNA concentrations of genes involved in cholesterol and bile acid metabolism. In conclusion, the present study shows that lupin protein has hypotriacylglycerolaemic action possibly via down regulation of fatty acid synthesis genes and up regulation of genes involved in TAG hydrolysis. Alterations in cholesterol metabolism could not be explained on the basis of mRNA data. Grain legumes are a valuable source of food proteins. Soyabean protein is among the most important legume proteins used for human nutrition. Besides its nutritional value, soyabean protein has been known to exert hypocholesterolaemic (1 -6) and hypotriacylglycerolaemic (5,7,8) action in laboratory animals, pigs and human subjects when compared with casein. Another protein-rich legume besides soya is lupin which has been cultivated for centuries, mainly for domestic animal feed, but also for human nutrition. Nowadays, four Mediterranean species of lupin (Lupinus albus, L. angustifolius, L. luteus and L. mutabilis) are cultivated for nutrition and they are referred to as sweet lupins since they contain smaller amounts of toxic alkaloids than the bitter varieties. The protein and amino acid contents of lupin seeds and soya are very similar, but the amount of isoflavones is minimal in lupin (9,10) . Sirtori et al. (9) have recently shown that lupin protein extract reduces cholesterolaemia in hypercholesterolaemic rats. These authors also found that lupin protein increases the activity of the LDL receptor in HepG2 cells, which could be an explanation for the hypocholesterolaemic effect observed in vivo. They also found a reduction of plasma TAG when hypercholesterolaemic rats were fed lupin ...
Low levels of 25-hydroxy vitamin D (25(OH)D) are associated with cardiovascular diseases. Herein, we tested the hypothesis that vitamin D deficiency could be a causal factor in atherosclerotic vascular changes and vascular calcification. Aortic root sections of vitamin D receptor knockout (VDR−/−) mice that were stained for vascular calcification and immunostained for osteoblastic differentiation factors showed more calcified areas and a higher expression of the osteogenic key factors Msx2, Bmp2, and Runx2 than the wild-type mice (P<0.01). Data from LDL receptor knockout (LDLR−/−) mice that were fed western diet with either low (50 IU/kg), recommended (1,000 IU/kg), or high (10,000 IU/kg) amounts of vitamin D3 over 16 weeks revealed increasing plasma concentrations of 25(OH)D (P<0.001) with increasing intake of vitamin D, whereas levels of calcium and phosphorus in plasma and femur were not influenced by the dietary treatment. Mice treated with the low vitamin D diet had more calcified lesions and a higher expression of Msx2, Bmp2, and Runx2 in aortic roots than mice fed recommended or high amounts of vitamin D (P<0.001). Taken together, these findings indicate vitamin D deficiency as a risk factor for aortic valve and aortic vessel calcification and a stimulator of osteogenic key factor expression in these vascular areas.
What is already known about this subject?There is evidence that NK cell functionality is severely altered in obesity. Our group and others have shown distinct loss of function (e.g. cytotoxicity and cytokine production) of NK cells from individuals with obesity and experimental animals. What does this study add?For the first time, the present study demonstrates a re-activation of NK cell functionality after fat mass reduction as a consequence of a combined exercise and dietary program in person with obesity. Conclusion:The present study demonstrates a re-activation of NK cell functionality after body fat mass reduction in person with obesity.
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