scholarly journals IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2859
Author(s):  
Asahi Takeuchi ◽  
Kentaro Hisamatsu ◽  
Natsuki Okumura ◽  
Yuki Sugimitsu ◽  
Emiko Yanase ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Bovine Milk ◽  
Cholesterol Absorption ◽  
Molecular Probe ◽  
Small Intestinal Mucosa ◽  
Intestinal Alkaline Phosphatase ◽  
Intestinal Cholesterol Absorption ◽  
Protein Levels

IIAEK (Ile-Ile-Ala-Glu-Lys, lactostatin) is a novel cholesterol-lowering pentapeptide derived from bovine milk β-lactoglobulin. However, the molecular mechanisms underlying the IIAEK-mediated suppression of intestinal cholesterol absorption are unknown. Therefore, we evaluated the effects of IIAEK on intestinal cholesterol metabolism in a human intestinal model using Caco-2 cells. We found that IIAEK significantly reduced the expression of intestinal cholesterol metabolism-associated genes, particularly that of the ATP-binding cassette transporter A1 (ABCA1). Subsequently, we chemically synthesized a novel molecular probe, IIXEK, which can visualize a complex of target proteins interacting with photoaffinity-labeled IIAEK by fluorescent substances. Through photoaffinity labeling and MS analysis with IIXEK for the rat small intestinal mucosa and intestinal lipid raft fractions of Caco-2 cells, we identified intestinal alkaline phosphatase (IAP) as a specific molecule interacting with IIAEK and discovered the common IIAEK-binding amino acid sequence, GFYLFVEGGR. IIAEK significantly increased IAP mRNA and protein levels while decreasing ABCA1 mRNA and protein levels in Caco-2 cells. In conclusion, we found that IIAEK targets IAP to improve cholesterol metabolism via a novel signaling pathway involving the specific activation of IAP and downregulation of intestinal ABCA1.

scholarly journals IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Down-Regulation of ABCA1

2020 ◽  
Author(s):  
Asahi Takeuchi ◽  
Kentaro Hisamatsu ◽  
Natsuki Okumura ◽  
Yuki Sugimitsu ◽  
Emiko Yanase ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Molecular Probe ◽  
Small Intestinal Mucosa ◽  
Mrna Levels ◽  
Intestinal Alkaline Phosphatase ◽  
Down Regulation ◽  
Protein Levels ◽  
Abca1 Mrna

IIAEK (Ile-Ile-Ala-Glu-Lys, lactostatin) is a novel pentapeptide from bovine milk β-lactoglobulin which lowers cholesterol levels. However, the molecular mechanisms underlying the suppression of intestinal cholesterol absorption by IIAEK are unknown. Therefore, we evaluated the effects of IIAEK on intestinal cholesterol metabolism in Caco-2 cells in a human intestinal model. We found that IIAEK significantly reduced the expression of intestinal cholesterol metabolism-associated genes, particularly that of the ATP-binding cassette transporter A1 (ABCA1) protein. Subsequently, we chemically synthesized a novel molecular probe, IIXEK, which can visualize a complex of target proteins interacting with photoaffinity-labeled IIAEK by fluorescent substances. Photoaffinity labeling and MS analysis with IIXEK for the rat small intestinal mucosa and intestinal lipid raft fractions of Caco-2 cells, we identified intestinal alkaline phosphatase (IAP) as a specific molecule interacting with IIAEK and discovered IIAEK common binding amino acid sequence, GFYLFVEGGR. Transfection of IAP siRNA counteracted the decrease in ABCA1 mRNA levels in Caco-2 cells. IIAEK significantly increased IAP mRNA and protein levels, and significantly decreased ABCA1 mRNA and protein levels in Caco-2 cells. In conclusion, we found that IIAEK targets IAP to improve cholesterol metabolism via a novel signaling pathway with a specific activation of IAP and down-regulation of intestinal ABCA1.

scholarly journals Recombinant Human Tissue Non-Specific Alkaline Phosphatase Successfully Counteracts Lipopolysaccharide Induced Sepsis in Mice

2015 ◽  
pp. 731-738 ◽  
Author(s):  
B. BENDER ◽  
M. BARANYI ◽  
A. KEREKES ◽  
L. BODROGI ◽  
R. BRANDS ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Intravenous Injection ◽  
Human Tissue ◽  
Molecular Mechanisms ◽  
Multiple Organ ◽  
Control Group ◽  
Intestinal Alkaline Phosphatase ◽  
Specific Alkaline Phosphatase ◽  
Transgenic Rabbits ◽  
Rabbit Milk

Sepsis is a life threatening condition that arises when the body's response to an infection injures its own tissues and organs. Sepsis can lead to shock, multiple organ failure and death especially if not recognized early and treated promptly. Molecular mechanisms underlying the systemic inflammatory response syndrome associated with sepsis are still not completely defined and most therapies developed to target the acute inflammatory component of the disease are insufficient. In this study we investigated a possibility of combating sepsis in a mouse model by intravenous treatment with recombinant human tissue non-specific alkaline phosphatase (rhTNAP) derived from transgenic rabbit milk. We induced sepsis in mice by intraperitoneal injection of LPS and three hours later treated experimental group of mice by intravenous injection with rhTNAP derived from transgenic rabbits. Such treatment was proved to be physiologically effective in this model, as administration of recombinant rhTNAP successfully combated the decrease in body temperature and resulted in increased survival of mice (80 % vs. 30 % in a control group). In a control experiment, also the administration of bovine intestinal alkaline phosphatase by intravenous injection proved to be effective in increasing survival of mice treated with LPS. Altogether, present work demonstrates the redeeming effect of the recombinant tissue non-specific AP derived from milk of genetically modified rabbits in combating sepsis induced by LPS.

scholarly journals Pinto Beans (Phaseolus vulgaris L.) Lower Non-HDL Cholesterol in Hamsters Fed a Diet Rich in Saturated Fat and Act on Genes Involved in Cholesterol Homeostasis

2019 ◽  
Vol 149 (6) ◽  
pp. 996-1003 ◽  
Author(s):  
An Tien Nguyen ◽  
Sami Althwab ◽  
Haowen Qiu ◽  
Richard Zbasnik ◽  
Carlos Urrea ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Saturated Fatty Acids ◽  
Saturated Fat ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Liver Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Pinto Beans

ABSTRACT Background Pinto beans contain multiple active agents such as polyphenols, flavonoids, and saponins, and have been shown to lower cholesterol, but the mechanisms involved in this effect have not been explored. Objective This study was to investigate the changes in cholesterol metabolism in response to whole pinto beans (wPB) and their hulls (hPB) supplemented into a diet rich in saturated fat and the molecular mechanisms potentially responsible for these effects in hamsters. Methods Forty-four 9-wk-old male Golden Syrian hamsters were randomly assigned to 4 diet groups (n = 11), including a 5% (wt:wt) fat diet [normal-fat diet (NF)], a 15% (wt:wt) fat diet [diet rich in saturated fat (HSF), saturated fatty acids accounted for 70% of total fatty acids], or HSF supplemented with 5% (wt:wt) wPB or 0.5% (wt:wt) hPB for 4 wk. Plasma, liver, intestinal, and fecal samples were collected to evaluate multiple cholesterol markers and gene targets. Results The plasma non-high-density lipoprotein (non-HDL) concentration was significantly reduced in the wPB- and hPB-supplemented groups by 31.9 ± 3.5% and 53.6 ± 3.2%, respectively, compared with the HSF group (P < 0.01), to concentrations comparable with the NF group. The wPB-supplemented hamsters had significantly lower liver cholesterol (45.1%, P < 0.001) and higher fecal cholesterol concentrations (94.8%, P = 0.001) than those fed the HSF. The expressions of hepatic 3-hydroxy-3-methylglutaryl CoA reductase (Hmgcr) and small intestinal acyl-coenzyme A: cholesterol acyltransferase 2 (Acat2) were significantly decreased in animals administered wPB (by 89.1% and 63.8%, respectively) and hPB (by 72.9% and 47.7%, respectively) compared with their HSF-fed counterparts (P < 0.05). The wPB normalized the expression of Acat2 to the level of the NF group. Conclusion Pinto beans remediated high cholesterol induced by HSF in male hamsters by decreasing hepatic cholesterol synthesis and intestinal cholesterol absorption, effects which were partially exerted by the hulls.

scholarly journals Intestine-Specific Overexpression of LDLR Enhances Cholesterol Excretion and Induces Metabolic Changes in Male Mice

Endocrinology ◽  
2018 ◽  
Vol 160 (4) ◽  
pp. 744-758 ◽  
Author(s):  
Luca Meoli ◽  
Danny Ben-Zvi ◽  
Courtney Panciotti ◽  
Stephanie Kvas ◽  
Palmenia Pizarro ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Treatment Options ◽  
Density Lipoprotein ◽  
Cholesterol Absorption ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Metabolic Effects ◽  
Cholesterol Levels ◽  
Cholesterol Excretion

Abstract Roux-en-Y gastric bypass (RYGB) surgery is one of the most effective treatment options for severe obesity and related comorbidities, including hyperlipidemia, a well-established risk factor of cardiovascular diseases. Elucidating the molecular mechanisms underlying the beneficial effects of RYGB may facilitate development of equally effective, but less invasive, treatments. Recent studies have revealed that RYGB increases low-density lipoprotein receptor (LDLR) expression in the intestine of rodents. Therefore, in this study we first examined the effects of RYGB on intestinal cholesterol metabolism in human patients, and we show that they also exhibit profound changes and increased LDLR expression. We then hypothesized that the upregulation of intestinal LDLR may be sufficient to decrease circulating cholesterol levels. To this end, we generated and studied mice that overexpress human LDLR specifically in the intestine. This perturbation significantly affected intestinal metabolism, augmented fecal cholesterol excretion, and induced a reciprocal suppression of the machinery related to luminal cholesterol absorption and bile acid synthesis. Circulating cholesterol levels were significantly decreased and, remarkably, several other metabolic effects were similar to those observed in RYGB-treated rodents and patients, including improved glucose metabolism. These data highlight the importance of intestinal cholesterol metabolism for the beneficial metabolic effects of RYGB and for the treatment of hyperlipidemia.

Role of intestinal sterol transporters Abcg5, Abcg8, and Npc1l1 in cholesterol absorption in mice: gender and age effects

2006 ◽  
Vol 290 (2) ◽  
pp. G269-G276 ◽  
Author(s):  
Li-Ping Duan ◽  
Helen H. Wang ◽  
Akira Ohashi ◽  
David Q.-H. Wang
Keyword(s):  
Molecular Mechanisms ◽  
Apical Membrane ◽  
Cholesterol Absorption ◽  
Absorption Efficiency ◽  
Biliary Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Gender And Age ◽  
Multistep Process ◽  
17Β Estradiol

Recent studies have indicated that intestinal cholesterol absorption is a multistep process, which is regulated by multiple genes at the enterocyte level. However, the molecular mechanisms whereby there are gender differences in intestinal cholesterol absorption efficiency and the efficiency of cholesterol absorption increases with age have not yet been fully understood. To explore whether aging increases cholesterol absorption via intestinal sterol transporters, we studied the higher cholesterol-absorbing C57L/J vs. the lower cholesterol-absorbing AKR/J mice at 8 (young adult), 36 (older adult), and 50 (aged) wk of age. To test the hypothesis that estrogen receptor (ER )α plays an important regulatory role in cholesterol absorption, we investigated the gonadectomized mice of both genders treated with 17β-estradiol-releasing pellets at 0, 3, or 6 μg/day and antiestrogenic ICI 182,780 at 125 μg/day. We found that hepatic outputs of biliary cholesterol were significantly increased with age and in response to high levels of estrogen. Aging significantly enhances cholesterol absorption by suppressing expression of the jejunal and ileal sterol efflux transporters [ATP-binding cassette ( Abc) g5 and Abcg8] and upregulating expression of the putative duodenal and jejunal sterol influx transporter Npc1l1. Estrogen significantly augmented cholesterol absorption mostly due to an upregulated expression of intestinal Npc1l1, Abcg5, and Abcg8 via the intestinal ERα pathway, which can be fully abolished by the antagonist. We conclude that ERα activated by estrogen and aging enhances cholesterol absorption by increasing biliary lipid output and mediating intestinal sterol transporters favoring influx of intraluminal cholesterol molecules across the apical membrane of the enterocyte.

A novel Sp1-relatedciselement involved in intestinal alkaline phosphatase gene transcription

1999 ◽  
Vol 276 (4) ◽  
pp. G800-G807 ◽  
Author(s):  
Jeong H. Kim ◽  
Shufen Meng ◽  
Amy Shei ◽  
Richard A. Hodin
Keyword(s):  
Alkaline Phosphatase ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Regulatory Element ◽  
Gene Activation ◽  
Regulatory Region ◽  
Intestinal Alkaline Phosphatase ◽  
Mobility Shift ◽  
Sv40 Promoter

We have used sodium butyrate-treated HT-29 cells as an in vitro model system to study the molecular mechanisms underlying intestinal alkaline phosphatase (IAP) gene activation. Transient transfection assays using human IAP-CAT reporter genes along with DNase I footprinting were used to localize a critical cis element (IF-III) corresponding to the sequence 5′-GACTGGGCGGGGTCAAGATGGA-3′. Deletion of the IF-III element resulted in a dramatic reduction in reporter gene activity, and IF-III was shown to function in the context of a heterologous (SV40) promoter in a cell type-specific manner, further supporting its functional role in IAP transactivation. Electrophoretic mobility shift assays revealed that IF-III binds Sp1 and Sp3, but these factors comprise only a portion of the total nuclear binding and appear to mediate only a small portion of its transcriptional activity. IF-III does not correspond to any previously characterized regulatory region from other intestine-specific genes. We have thus identified a novel, Sp1-related cis-regulatory element in the human IAP gene that appears to play a role in its transcriptional activation during differentiation in vitro.

Molecular Insights into the Mechanisms Underlying the Cholesterol- Lowering Effects of Phytosterols

2019 ◽  
Vol 26 (37) ◽  
pp. 6704-6723 ◽  
Author(s):  
Lídia Cedó ◽  
Marta Farràs ◽  
Miriam Lee-Rueckert ◽  
Joan Carles Escolà-Gil
Keyword(s):  
Bile Acids ◽  
Molecular Mechanisms ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Absorption ◽  
Plant Sterols ◽  
Intestinal Lumen ◽  
Low Density ◽  
Intestinal Cholesterol Absorption ◽  
Cholesterol Lowering

Dietary phytosterols, which comprise plant sterols and stanols, reduce plasma Low-Density Lipoprotein-Cholesterol (LDL-C) levels when given 2 g/day. Since this dose has not been reported to cause health-related side effects in long-term human studies, food products containing these plant compounds are used as potential therapeutic dietary options to reduce LDL-C and cardiovascular disease risk. Several mechanisms have been proposed to explain the cholesterol-lowering action of phytosterols. They may compete with dietary and biliary cholesterol for micellar solubilization in the intestinal lumen, impairing intestinal cholesterol absorption. Recent evidence indicates that phytosterols may also regulate other pathways. Impaired intestinal cholesterol absorption is usually associated with reduced cholesterol transport to the liver, which may reduce the incorporation of cholesterol into Very-Low- Density Lipoprotein (VLDL) particles, thereby lowering the rate of VLDL assembly and secretion. Impaired liver VLDL production may reduce the rate of LDL production. On the other hand, significant evidence supports a role for plant sterols in the Transintestinal Cholesterol Excretion (TICE) pathway, although the exact mechanisms by which they promote the flow of cholesterol from the blood to enterocytes and the intestinal lumen remains unknown. Dietary phytosterols may also alter the conversion of bile acids into secondary bile acids, and may lower the bile acid hydrophobic/hydrophilic ratio, thereby reducing intestinal cholesterol absorption. This article reviews the progress to date in research on the molecular mechanisms underlying the cholesterol-lowering effects of phytosterols.

Plasma Non-cholesterol Sterols as Markers of Cholesterol Synthesis and Intestinal Absorption: A Critical Review

2020 ◽  
Vol 26 (40) ◽  
pp. 5152-5162
Author(s):  
Eder Carlos Rocha Quintão
Keyword(s):  
Intestinal Absorption ◽  
Cholesterol Synthesis ◽  
Cholesterol Metabolism ◽  
Plasma Concentrations ◽  
Cholesterol Absorption ◽  
Population Based ◽  
Whole Body ◽  
Intestinal Lumen ◽  
Intestinal Cholesterol Absorption ◽  
Artery Disease

Plasma concentrations of phytosterols and non-cholesterol sterol precursors of cholesterol synthesis have been used as markers of intestinal cholesterol absorption and synthesis in inherited and secondary dyslipidemias and in population-based investigations to evaluate the risk for cardiovascular disease, respectively. The method aims at replacing initial research procedures such as the use of stable isotopes associated with fecal steroid balance, which are limited by the high cost and tedious procedures. However, we show in this review that numerous results obtained with serum sterol measurements are contradictory. In this regard, the following points are discussed: 1) how phytosterols relate to atherosclerosis considering that defects in biliary output or in the transport of phytosterols from the intestinal mucosa back into the intestinal lumen provide increased content of phytosterols and other sterols in plasma and tissues, thus not allowing to conclude that their presence in arteries and atheromas represents the etiology of atherosclerosis; 2) serum non-cholesterol sterols as markers of cholesterol synthesis and absorption, such as cholestanol, present discrepant results, rendering them often inadequate to identify cases of coronary artery disease as well as alterations in the whole body cholesterol metabolism; 3) such methods of measurement of cholesterol metabolism are confounded by factors like diabetes mellitus, body weight and other pathologies including considerable hereditary hyperlipidemias biological variabilities that influence the efficiency of synthesis and intestinal absorption of cholesterol.

Prevalence and Properties of the Intestinal Alkaline Phosphatase Identified in Serum by Cellulose Acetate Electrophoresis

1992 ◽  
Vol 38 (4) ◽  
pp. 507-511 ◽  
Author(s):  
W C Griffiths ◽  
P D Camara ◽  
M Rosner ◽  
R Lev ◽  
E M Brooks
Keyword(s):  
Alkaline Phosphatase ◽  
Cellulose Acetate ◽  
Colonic Mucosa ◽  
Small Intestinal Mucosa ◽  
Fasting Serum ◽  
Intestinal Alkaline Phosphatase ◽  
Serum Samples ◽  
Cellulose Acetate Electrophoresis ◽  
Hospital Patients ◽  
Small Intestinal

Abstract We investigated the prevalence and characteristics of intestinal alkaline phosphatase (ALP; EC 3.1.3.1) identified in human serum by cellulose acetate electrophoresis in 8% of fasting serum samples from hospital patients (n = 500) and in 35% of fasting serum samples from patients with diabetes mellitus (n = 106; not differentiated between types 1 and 2). The intestinal ALP electrophoretic band was usually heterogeneous and contained two major subtypes of ALP. Isoelectric focusing of intestinal-ALP-positive serum treated with levamisole and neuraminidase (EC 3.2.1.18) revealed two distinct regions of enzymatic activity that comigrated with ALP extracted from small intestinal and colonic mucosa. Anodic intestinal ALP was resistant to treatment with levamisole and neuraminidase and comigrated with ALP from small intestinal mucosa. The more-cathodic intestinal ALP, which comigrated with ALP from colonic mucosa, was completely inhibited by levamisole and converted by neuraminidase to a species with a more basic pI than that of neuraminidase-digested tissue-nonspecific form. This component of intestinal ALP may be of vascular origin.

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