ABSTRACT
Renal tubular ectopic lipid deposition (ELD) plays a significant role in the development of chronic kidney disease, posing a great threat to human health. The present work aimed to explore the intervention effect and potential molecular mechanism of a purified tea polysaccharide (TPS3A) on renal tubular ELD. The results demonstrated that TPS3A effectively improved kidney function and slowed the progression of tubulointerstitial fibrosis in high-fat-diet (HFD)-exposed ApoE-/- mice. Additionally, TPS3A notably suppressed lipogenesis and enhanced lipolysis, as shown by the downregulation of lipogenesis markers (SREBP-1 and FAS) and the upregulation of lipolysis markers (HSL and ATGL), thereby reducing renal tubular ELD in HFD-fed ApoE-/- mice and palmitic-acid-stimulated HK-2 cells. The AMPK-SIRT1-FoxO1 axis is a core signal pathway in regulating lipid deposition. Consistently, TPS3A significantly increased the levels of phosphorylated-AMPK, SIRT1, and deacetylation of Ac-FoxO1. However, these effects of TPS3A on lipogenesis and lipolysis were abolished by AMPK siRNA, SIRT1 siRNA, and FoxO1 inhibitor, resulting in exacerbated lipid deposition. Taken together, TPS3A shows promise in ameliorating renal tubular ELD by inhibiting lipogenesis and promoting lipolysis through the AMPK-SIRT1-FoxO1 signaling pathway.
Subject(s)
Diet, High-Fat , Lipogenesis , Lipolysis , Mice, Inbred C57BL , Polysaccharides , Animals , Lipogenesis/drug effects , Mice , Lipolysis/drug effects , Male , Diet, High-Fat/adverse effects , Humans , Polysaccharides/pharmacology , Polysaccharides/administration & dosage , Sirtuin 1/metabolism , Sirtuin 1/genetics , Forkhead Box Protein O1/metabolism , Forkhead Box Protein O1/genetics , Kidney Tubules/metabolism , Kidney Tubules/drug effects , Camellia sinensis/chemistry , AMP-Activated Protein Kinases/metabolism , AMP-Activated Protein Kinases/genetics , Plant Extracts/pharmacology , Plant Extracts/administration & dosage , Tea/chemistry , Sterol Regulatory Element Binding Protein 1/metabolism , Sterol Regulatory Element Binding Protein 1/geneticsABSTRACT
A new homogeneous polysaccharide (TPS3A) was isolated and purified from Tianzhu Xianyue fried green tea by DEAE-52 cellulose and Sephacryl S-500 column chromatography. Structural characterization indicated that TPS3A mainly consisted of arabinose, galactose, galacturonic acid and rhamnose in a molar ratio of 5.84: 4.15: 2.06: 1, with an average molecular weight of 1.596 × 104 kDa. The structure of TPS3A was characterized as a repeating unit consisting of 1,3-Galp, 1,4-Galp, 1,3,6-Galp, 1,3-Araf, 1,5-Araf, 1,2,4-Rhap and 1-GalpA, with two branches on the C6 of 1,3,6-Galp and C2 of 1,2,4-Rhap, respectively. To investigate the preventive effects of TPS3A on atherosclerosis, TPS3A was administered orally to ApoE-deficient (ApoE-/-) mice. Results revealed that TPS3A intervention could effectively delay the atherosclerotic plaque progression, modulate dyslipidemia, and reduce the transformation of vascular smooth muscle cells (VSMCs) from contractile phenotype to synthetic phenotype by activating the expression of contractile marker alpha-smooth muscle actin (α-SMA) and inhibiting the expression of synthetic marker osteopontin (OPN) in high-fat diet-induced ApoE-/- mice. Our findings suggested that TPS3A markedly alleviated atherosclerosis by regulating dyslipidemia and phenotypic transition of VSMCs, and might be used as a novel functional ingredient to promote cardiovascular health.
Subject(s)
Atherosclerosis , Dyslipidemias , Animals , Mice , Tea , Polysaccharides/pharmacology , Polysaccharides/therapeutic use , Polysaccharides/analysis , Atherosclerosis/drug therapy , Apolipoproteins EABSTRACT
The effects of lotus root amylopectin (LRA) on the formation of whey protein isolate (WPI) gels were investigated at the concentration range from 0 to 1.0% (w/v) by determining the texteral, thermal and rheological properties. Results exhibited these properties of WPI gels could be significantly enhanced by the addition of LRA in a concentration-dependent manner. Compared the gel with free of starch, the gel strength, water holding capacity and thermal transition temperature of WPI gel containing 1% (w/v) amylopectin were enhanced by 12.7-fold, 24.9% and 3.6°C, respectively. According to the analysis of scanning electron microscopy, colorimetric reaction and Fourier transform infrared spectroscopy measurements, it was concluded that the LRA-induced enhancement of WPI gel properties was possibly attributed to the formation of stable three-dimensional gel network, increased contents of reactive sulfhydryl group, CN bond and/or NH bond. Results suggested that LRA might be a good gel modifier.
Subject(s)
Amylopectin/chemistry , Gels , Nelumbo/chemistry , Whey Proteins/chemistry , Milk Proteins , Plant Roots/chemistry , Rheology , StarchABSTRACT
The potential biodegradation of crude oil was assessed based on the development of a fermentative process with a strain of Pseudomonas aeruginosa which produced 15.4 g/L rhamnolipids when cultured in a basal mineral medium using glycerol as a sole carbon source. However, neither cell growth nor rhamnolipid production was observed in the comparative culture system using crude oil as the sole carbon source instead. As rhamnolipid, an effective biosurfactant, has been reported to stimulate the biodegradation of hydrocarbons, 1 g/L glycerol or 0.22 g/L rhamnolipid was initially added into the medium to facilitate the biodegradation of crude oil. In both situations, more than 58% of crude oil was degraded and further converted into accumulated cell biomass and rhamnolipids. These results suggest that Pseudomonas aeruginosa could degrade most of crude oil with direct or indirect addition of rhamnolipid. And this conclusion was further supported by another adsorption experiment, where the adsorption capacity of crude oil by killed cell biomass was negligible in comparison with the biologic activities of live cell biomass.
