scholarly journals Renal mass reduction results in accumulation of lipids and dysregulation of lipid regulatory proteins in the remnant kidney

2009 ◽  
Vol 296 (6) ◽  
pp. F1297-F1306 ◽  
Author(s):  
Hyun Ju Kim ◽  
Hamid Moradi ◽  
Jun Yuan ◽  
Keith Norris ◽  
Nosratola D. Vaziri

A significant reduction of renal mass results in proteinuria, glomerulosclerosis, and tubulointerstitial injury, culminating in end-stage chronic renal failure (CRF). The accumulation of lipids in the kidney can cause renal disease. Uptake of oxidized lipoproteins via scavenger receptors, reabsorption of filtered protein-bound lipids via the megalin-cubilin complex, and increased glucose load per nephron can promote lipid accumulation in glomerular, tubular, and interstitial cells in CRF. Cellular lipid homeostasis is regulated by lipid influx, synthesis, catabolism, and efflux. We examined lipid-regulatory factors in the remnant kidney of rats 11 wk after nephrectomy (CRF) or sham operation. CRF resulted in azotemia, proteinuria, lipid accumulation in the kidney, upregulation of megalin, cubilin, mediators of lipid influx (scavenger receptor class A and lectin-like oxidized receptor-1), lipid efflux (liver X receptor α/β and ATP-binding cassette transporter), and fatty acid biosynthesis (carbohydrate-response element binding protein, fatty acid synthase, and acetyl-CoA carboxylase). However, factors involved in cholesterol biosynthesis (sterol regulatory element binding protein, 3-hydroxy-3-methylglutaryl coenzyme A reductase, SCAP, Insig-1, and Insig-2) and fatty acid oxidation (peroxisome proliferator-activated receptor, acyl-CoA oxidase, and liver-type fatty acid binding protein) were reduced in the remnant kidney. Thus CRF results in heavy lipid accumulation in the remnant kidney, which is mediated by upregulation of pathways involved in tubular reabsorption of filtered protein-bound lipids, influx of oxidized lipoproteins and synthesis of fatty acids, and downregulation of pathways involved in fatty acid catabolism.

2020 ◽  
Vol 318 (3) ◽  
pp. F826-F834
Author(s):  
Gaizun Hu ◽  
Lusi Xu ◽  
Yixuan Ma ◽  
Masahiro Kohzuki ◽  
Osamu Ito

Excessive fructose intake causes metabolic syndrome and lipid accumulation in the kidney and leads to renal dysfunction and damage. Exercise (Ex) improves lipids regulation, but the mechanisms are unclarified in the kidney. In the present study, male Sprague-Dawley rats were allocated to groups fed with control or high-fructose (HFr) diet. Part of rats in each group underwent aerobic treadmill Ex for 12 wk. Drug treatment was performed as the fenofibrate gavage during the last 4 wk on HFr diet-fed rats. Renal function, histological changes, and expression of regulators involved in fatty acid (FA) metabolism were assessed. In CON diet-fed groups, Ex did not affect renal function or histology and significantly increased renal expression of FA β-oxidation regulators including acyl-CoA dehydrogenases (CADs), acyl-CoA oxidase, peroxisome proliferator-activated receptor (PPAR)-α, and PPAR-γ coactivator (PGC)-1α and lipogenic factors including acetyl-CoA carboxylase (ACCα), FA synthase (FAS), and sterol regulatory element-binding protein 1c. HFr caused albuminuria, lipid accumulation, and renal pathohistological changes, which were attenuated by Ex but not by fenofibrate. HFr decreased renal expression of medium- and short-chain CADs and PPAR-α and increased renal expression of ACCα, FAS, and sterol regulatory element-binding protein 1c. Ex increased expression of CADs, carnitine palmitoyltransferase type I, acyl-CoA oxidase, PPAR-α, and PGC-1α and decreased renal expression of ACCα and FAS in HFr diet-fed rats. The Ex-induced FA metabolism alteration was similar to that in the fenofibrate-treated group. In conclusion, the present study indicates that Ex enhanced renal FA metabolism, which might protect the kidney in lipid dysregulation diseases.


2020 ◽  
Author(s):  
Hang-Hee Cho ◽  
Soo-Jung Lee ◽  
Sung-Ho Kim ◽  
Sun-Hee Jang ◽  
Chungkil Won ◽  
...  

Abstract Background: The aim of this study was to investigate the effect of Acer tegmentosum Maxim (ATM) on adipocyte differentiation in 3T3-L1 adipocyte-derived cells and anti-obesity properties in high fat diet (HFD)-induced obese rats. Methods: 3T3-L1 adipocytes and HFD-induced obese rats were treated with ATM, and its effect on gene expression was analyzed using RT-PCR and Western blotting experiments. Results: Cellular lipid contents in DMI (dexamethasone, 3-isobutyl-1-methylxanthine, and insulin mixture)-treated cells increased, while ATM treatment caused a significant reduction in lipid accumulation in differentiated 3T3-L1 cells. ATM caused inhibition of adipogenesis via down-regulation of the CCAAT/enhancer binding protein β (C/EBPβ), C/EBPα, and peroxisome proliferator-activated receptor γ (PPARγ) expressions in 3T3-L1 cells. Moreover, treatment with ATM caused a decrease in the expressions of adipocyte-specific genes, such as adipocyte fatty acid-binding protein-2 (aP2), fatty acid synthase (FAS), and lipoprotein lipase (LPL), compared with DMI-stimulated adipocytes. In addition, phosphorylation levels of protein kinase B (Akt) and its downstream substrate, glycogen synthase kinase 3β (GSK3β), were significantly decreased by ATM treatment of 3T3-L1 adipocytes. Together, these results indicated that ATM caused inhibition of both adipocyte differentiation via suppression of the C/EBP family and PPARγ expressions and the Akt signaling pathway in 3T3-L1 adipocytes. In the present study, we further investigated anti-obesity effects of ATM on HFD-induced obese rats. Rats fed with HFD demonstrated elevations in body weight gain, while the administration of ATM significantly reversed BW gains and adipose tissue weights in rats fed HFD. ATM supplementation also caused a decrease in the circulating triglyceride levels and total cholesterol levels and led to inhibition of lipid accumulation in the adipose tissues in HFD-induced obesity in rats. Furthermore, epididymal fat exhibited larger adipocytes in the HFD group, whereas the ATM-treated group was significantly smaller than that of HFD group. These results strongly demonstrate that ATM administration caused a reduction in adiposity via attenuation in adipose tissue mass and adipocyte size. Conclusion: These finding demonstrated that ATM exerted anti-obesity effects through inhibition of adipocyte differentiation and adipogenesis, leading to a decrease in BW and fat tissue mass in HFD-induced obesity in rats.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jeong-Eun Park ◽  
Suk-Heung Oh ◽  
Youn-Soo Cha

We investigated whether lactic acid bacteria isolated from gajami sik-hae (GLAB) are capable of reducing the intracellular lipid accumulation by downregulating the expression of adipogenesis-related genes in differentiated 3T3-L1 cells. The GLAB,Lactobacillus plantarumLG42, significantly decreased the intracellular triglyceride storage and the glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent manner. mRNA expression of transcription factors like peroxisome proliferator-activated receptor (PPAR)γand CCAAT/enhancer-binding protein (C/EBP)αinvolved in adipogenesis was markedly decreased by the GLAB treatment. Moreover, the GLAB also decreased the expression level of adipogenic markers like adipocyte fatty acid binding protein (aP2), leptin, GPDH, and fatty acid translocase (CD36) significantly. These results suggest that the GLAB inhibits lipid accumulation in the differentiated adipocyte through downregulating the expression of adipogenic transcription factors and other specific genes involved in lipid metabolism.


Endocrinology ◽  
2014 ◽  
Vol 155 (4) ◽  
pp. 1498-1509 ◽  
Author(s):  
Maria Schindler ◽  
Mareike Pendzialek ◽  
Alexander Navarrete Santos ◽  
Torsten Plösch ◽  
Stefanie Seyring ◽  
...  

According to the “developmental origin of health and disease” hypothesis, the metabolic set points of glucose and lipid metabolism are determined prenatally. In the case of a diabetic pregnancy, the embryo is exposed to higher glucose and lipid concentrations as early as during preimplantation development. We used the rabbit to study the effect of maternal diabetes type 1 on lipid accumulation and expression of lipogenic markers in preimplantation blastocysts. Accompanied by elevated triglyceride and glucose levels in the maternal blood, embryos from diabetic rabbits showed a massive intracellular lipid accumulation and increased expression of fatty acid transporter 4, fatty acid–binding protein 4, perilipin/adipophilin, and maturation of sterol-regulated element binding protein. However, expression of fatty acid synthase, a key enzyme for de novo synthesis of fatty acids, was not altered in vivo. During a short time in vitro culture of rabbit blastocysts, the accumulation of lipid droplets and expression of lipogenic markers were directly correlated with increasing glucose concentration, indicating that hyperglycemia leads to increased lipogenesis in the preimplantation embryo. Our study shows the decisive effect of glucose as the determining factor for fatty acid metabolism and intracellular lipid accumulation in preimplantation embryos.


2005 ◽  
Vol 288 (6) ◽  
pp. E1195-E1205 ◽  
Author(s):  
Susan E. Schadinger ◽  
Nancy L. R. Bucher ◽  
Barbara M. Schreiber ◽  
Stephen R. Farmer

Peroxisome proliferator-activated receptor-γ (PPARγ) is considered to be one of the master regulators of adipocyte differentiation. PPARγ2 is abundantly expressed in mature adipocytes and is elevated in the livers of animals that develop fatty livers. The aim of this study was to determine the ability of PPARγ2 to induce lipid accumulation in hepatocytes and to delineate molecular mechanisms driving this process. The hepatic cell line AML-12 was used to generate a cell line stably expressing PPARγ2. Oil Red O staining revealed that PPARγ2 induces lipid accumulation in hepatocytes. This phenotype is accompanied by a selective upregulation of several adipogenic and lipogenic genes including adipose differentiation-related protein (ADRP), adipocyte fatty acid-binding protein 4, sterol regulatory element-binding protein-1 (SREBP-1), fatty acid synthase (FAS), and acetyl-CoA carboxylase, genes whose expression levels are known to increase in steatotic livers of ob/ob mice. Furthermore, the PPARγ2-regulated induction of both SREBP-1 and FAS parallels an increase in de novo triacylglycerol synthesis in hepatocytes. Triacylglycerol synthesis and lipid accumulation are further enhanced by culturing hepatocytes with troglitazone in the absence of exogenous lipids. These results correspond with an increase in the lipid droplet protein, ADRP, and the data demonstrate that ADRP functions to coat lipid droplets in hepatocytes as observed by confocal microscopy. Taken together, these observations propose a role for PPARγ2 as an inducer of steatosis in hepatocytes and suggest that this phenomenon occurs through an induction of pathways regulating de novo lipid synthesis.


2021 ◽  
Vol 22 (21) ◽  
pp. 11409
Author(s):  
Sung Ho Lim ◽  
Ho Seon Lee ◽  
Hyo-Kyung Han ◽  
Chang-Ik Choi

Obesity is a lipid metabolism disorder caused by genetic, medicinal, nutritional, and other environmental factors. It is characterized by a complex condition of excess lipid accumulation in adipocytes. Adipogenesis is a differentiation process that converts preadipocytes into mature adipocytes and contributes to excessive fat deposition. Saikosaponin A (SSA) and saikosaponin D (SSD) are triterpenoid saponins separated from the root of the Bupleurum chinensis, which has long been used to treat inflammation, fever, and liver diseases. However, the effects of these constituents on lipid accumulation and obesity are poorly understood. We investigated the anti-obesity effects of SSA and SSD in mouse 3T3-L1 adipocytes. The MTT assay was performed to measure cell viability, and Oil Red O staining was conducted to determine lipid accumulation. Various adipogenic transcription factors were evaluated at the protein and mRNA levels by Western blot assay and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Here, we showed that SSA and SSD significantly inhibited lipid accumulation without affecting cell viability within the range of the tested concentrations (0.938–15 µM). SSA and SSD also dose-dependently suppressed the expression of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding protein alpha (C/EBPα), sterol regulatory element binding protein-1c (SREBP-1c), and adiponectin. Furthermore, the decrease of these transcriptional factors resulted in the repressed expression of several lipogenic genes including fatty acid binding protein (FABP4), fatty acid synthase (FAS), and lipoprotein lipase (LPL). In addition, SSA and SSD enhanced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylase (ACC), and inhibited the phosphorylation of extracellular-regulated kinase 1/2 (ERK1/2) and p38, but not c-Jun-N-terminal kinase (JNK). These results suggest that SSA and SSD inhibit adipogenesis through the AMPK or mitogen-activated protein kinase (MAPK) pathways in the early stages of adipocyte differentiation. This is the first study on the anti-adipogenic effects of SSA and SSD, and further research in animals and humans is necessary to confirm the potential of saikosaponins as therapeutic agents for obesity.


2021 ◽  
Vol 11 (19) ◽  
pp. 9224
Author(s):  
Hwa-Young Lee ◽  
Kwang Sik Suh ◽  
Young Il Kim ◽  
Bong-Keun Jang ◽  
Bo-Hyung Kim ◽  
...  

Obesity is caused by excessive fat cells and the overgrowth of adipocytes and is a major risk factor for several chronic illnesses. Aronia melanocarpa fruit is rich in anthocyanins and polyphenols and has protective effects against various diseases. In this study, we examined the effect of Aronia extract (Aronia bioactive fraction, ABF®) on the biomarkers of the adipogenic pathway during adipocyte differentiation of 3T3-L1 cells. Lipid accumulation was verified by Oil Red O staining. mRNA and protein expression of lipoprotein lipase (LPL), CCAAT/enhancer-binding protein α (C/EBPα), peroxisome proliferator-activated receptor γ (PPARγ), fatty acid-binding protein 2 (FABP2), and fatty acid synthase (FAS) were assayed by RT-qPCR and Western blot analyses. Adiponectin and leptin secretion were measured using enzyme-linked immunosorbent assays. ABF® treatment downregulated lipid accumulation based on Oil Red O staining. ABF®-treated cells exhibited decreased mRNA and protein expression of LPL, C/EBPα, PPARγ, FABP2, and FAS. Moreover, ABF® treatment significantly increased adiponectin secretion and decreased leptin secretion. In conclusion, ABF® has anti-adipogenic effects on the differentiation of 3T3-L1 cells and may be used as an anti-obesity nutraceutical.


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