REVIEW | doi:10.20944/preprints202208.0205.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: Cholesterol efflux; flavonoids; HDL; quercetin; reverse cholesterol transport
Online: 11 August 2022 (03:33:47 CEST)
One of the mechanisms used in the management and cure of atherosclerosis is reverse cholesterol transfer (RCT), which plays a vital role in the export of cholesterol from peripheral cells. Cholesterol efflux from macrophages in the subintima of the vessel wall is a critical part of RCT. ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) are involved in the transfer of cholesterol from arterial macrophages to extracellular high-density lipoprotein cholesterol (HDL). The HDL then transports esterified cholesterol to the liver for elimination. An important factor in the reverse cholesterol transport and excretion of extracellular cholesterol is HDL. Atherogenesis can be prevented by altering the processes of RCT and cholesterol efflux, and this might lead to novel treatment options for cardiovascular disease. Research of novel modifying variables for RCT and cholesterol efflux is necessary. A better understanding of RCT's molecular processes has been gained via research, allowing for the creation of new treatments that make use of RCT's potential for pharmacological improvement. The purpose of this review is to provoke discussion on the potential impact of selected flavonoids on cholesterol efflux on the progression of atherosclerosis (Fig. 1.).
REVIEW | doi:10.20944/preprints201809.0345.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: ATP-binding cassette G5/G8; brush border membrane; cholesterol absorption; Niemann-Pick C1-like 1; phytosterols; trans-intestinal cholesterol efflux; fecal neutral sterol excretion
Online: 18 September 2018 (10:46:34 CEST)
Hypercholesterolemia accelerates atherosclerosis, and extensive research has been undertaken to ameliorate this abnormality. Plant sterols have been shown to inhibit cholesterol absorption and lower plasma cholesterol level since the 1950s. This ingredient has recently been reappraised as a food additive that can be taken daily in a preclinical period to prevent hypercholesterolemia, considering that cardiovascular-related diseases are the top cause of death globally even with clinical interventions. Intestinal cholesterol handling is still elusive, making it difficult to clarify the mechanism for plant sterol-mediated inhibition. Notably, although the small intestine absorbs cholesterol, it is also the organ that excretes it abundantly, via trans-intestinal cholesterol efflux (TICE). In this review, we show a model where the brush border membrane (BBM) of intestinal epithelial cells stands as the dividing ridge for cholesterol fluxes, making cholesterol absorption and TICE inversely correlated. With this model, we tried to explain the plant sterol-mediated inhibitory mechanism. As well as cholesterol, plant sterols diffuse into the BBM but are effluxed back to the lumen rapidly. We propose that repeated plant sterol shuttling between the BBM and lumen promotes cholesterol efflux, and plant sterol in the BBM may disturb the trafficking machineries that transport cholesterol to the cell interior.
REVIEW | doi:10.20944/preprints202101.0409.v1
Online: 21 January 2021 (09:10:59 CET)
G-protein coupled receptors (GPCRs) are membrane proteins that convey extracellular signals to the cellular milieu. They represent a target for more than 30 % of currently marketed drugs. Here we review the effects of membrane cholesterol on the function of GPCRs of Class A. We review both the specific effects of cholesterol mediated via its direct high-affinity binding to the receptor and non-specific effects mediated by cholesterol-induced changes in the properties of the membrane. Cholesterol binds to many GPCRs at both canonical and non-canonical binding sites. It allosterically affects ligand binding to and activation of GPCRs. Also, it changes the oligomerization state of GPCRs. In this review, we consider a perspective of the potential for the development of new therapies that are targeted at manipulating the level of membrane cholesterol or modulating cholesterol binding sites on to GPCRs.
ARTICLE | doi:10.20944/preprints202008.0425.v1
Online: 20 August 2020 (05:13:23 CEST)
The translocator protein (TSPO) is a transmembrane protein present in the three domains of life. Its functional quaternary structure consists of one or more subunits. In mouse, the dimer-to-monomer equilibrium is shifted in vitro towards the monomer by adding cholesterol, a natural component of mammalian membranes. Here, we present a coarse-grained molecular dynamics study on the mouse protein in the presence of a physiological content and of an excess of cholesterol. The latter turns out to weaken the interfaces of the dimer by clusterizing mostly at the inter-monomeric space and pushing the contact residues apart. It also increases the compactness and the rigidity of the monomer. These two factors might play a role for the experimentally observed incremented stability of the monomeric form with increased content of cholesterol. Comparison with simulations on bacterial proteins suggests that the effect of cholesterol is much less pronounced for the latter than for the mouse protein.
ARTICLE | doi:10.20944/preprints202107.0024.v1
Subject: Medicine & Pharmacology, Allergology Keywords: high-density lipoprotein cholesterol; hypertension; blood pressure; low high-density lipoprotein cholesterol; extremely high high-density lipoprotein cholesterol; body mass index; big data
Online: 1 July 2021 (11:53:04 CEST)
Background Although high-density lipoprotein has cardioprotective effects, the association between serum high-density lipoprotein cholesterol (HDL-C) and hypertension is poorly understood. Objective We investigated whether low and high concentrations of HDL-C are associated with hypertension using a large healthcare dataset. Methods In a community-based cross-sectional study of 1,493,152 Japanese people aged 40–74 years who underwent a health checkup, blood pressures and clinical parameters, including nine HDL-C concentrations (20–110 mg/dL or over) were investigated. Results A crude U-shaped relationship was observed between the nine HDL-C concentrations and blood pressure in males (n = 830,669), while a left-to-right inverted J-shaped relationship was observed in females(n = 662,483). An age-adjusted logistic regression analysis showed J-shaped relationships (left-to-right inversion in females) between HDL-C and odds ratios for hypertension (≥140/90 mmHg), with lower limits of 60–79 mg/dL in males and 90–99 mg/dL in females, which were unchanged after adjusting for smoking, habitual exercise, alcohol consumption, and pharmacotherapy for hypertension, dyslipidemia, and diabetes. However, further adjustment for body mass index and serum triglyceride concentration revealed latent positive linear associations between HDL-C and hypertension, although the association between extremely high HDL-C (≥100 mg/dL) and hypertension was attenuated in non-alcohol drinkers. Conclusion Both low and extremely high HDL-C concentrations are associated with hypertension. The former association may be dependent on excess fat mass, which is often concomitant with low HDL-C, whereas the latter association may be dependent on frequent alcohol consumption.
ARTICLE | doi:10.20944/preprints201805.0301.v1
Online: 22 May 2018 (11:37:00 CEST)
The 2015 Dietary Guidelines for Americans recommends that individuals should eat as little dietary cholesterol as possible. However, current dietary cholesterol intake and its food sources have not been well-characterized. We examined dietary cholesterol intake by age, sex, race, and food sources using 24-hour dietary recall data from a nationally representative sample of 5047 adults aged 20 years or older who participated in NHANES (2013–2014 survey cycle). We also reported trends in cholesterol intake across the past 7 NHANES surveys. Mean dietary cholesterol intake was 293 mg/day (348 mg/day for males and 242 mg/day for females) in the 2013–2014 survey cycle; 39% of adults had dietary cholesterol intake above 300 mg/day (46% for males and 28% for females). Meat, eggs, grain products, and milk were the highest four food sources of cholesterol, contributing to 96% of the total consumption. Both average cholesterol intake and food source varied by age, sex, and race (each p < 0.05). Mean cholesterol intake of the overall population had been relatively constant at ~290 mg/day from 2001–2002 to 2013–2014 (p-trend = 0.98). These results should inform public health efforts in implementing dietary guidelines and tailoring dietary recommendations.
ARTICLE | doi:10.20944/preprints201801.0046.v2
Subject: Medicine & Pharmacology, Nutrition Keywords: cholesterol synthesis; bile acid synthesis; cholesterol absorption; lathosterol; plant sterols; oxysterols; lipoproteins; lipid lowering; phytosterols; placebo
Online: 10 January 2018 (10:51:03 CET)
Chitosan treatment results in significantly lower serum LDL cholesterol concentrations. To assess the working mechanism of chitosan, we measured serum surrogate markers of cholesterol absorption (campesterol, sitosterol, cholestanol), synthesis (lathosterol, lanosterol, desmosterol), and degradation to bile acids (7α-hydroxy-cholesterol, 27-hydroxy-cholesterol) corrected for cholesterol concentration (R_sterols). Over 12 weeks, 116 obese subjects (BMI 31.7, range 28.1 – 38.9 kg/m2) were studied under chitosan (n=61) and placebo treatment (n=55). The participants were briefly educated regarding improvement of nutrition quality and energy expenditure. Daily chitosan intake was 3200 mg. Serum LDL cholesterol concentration decreased significantly more (P=0.0252) under chitosan (-8.67 ± 18.18 mg/dl, 5.6%) than under placebo treatment (-1.00 ± 24.22 mg/dl, 0.9%). This reduction was not associated with the expected greater decreases in markers of cholesterol absorption under chitosan treatment. Also, increase in markers of cholesterol synthesis and bile acid synthesis under chitosan treatment was not any greater than under placebo treatment. In conclusion, a significant selective reduction of serum LDL cholesterol under chitosan treatment is neither associated with a reduction of serum surrogate markers of cholesterol absorption nor with an increases of markers for cholesterol and bile acid synthesis.
REVIEW | doi:10.20944/preprints202205.0290.v1
Subject: Life Sciences, Other Keywords: Cholesterol; PCSK9 inhibitors; HMG-CoA; LDL receptor; statins
Online: 23 May 2022 (10:01:24 CEST)
Proprotein convertase subtilisin/Kexin type 9 (PCSK9) is a proteolytic enzyme that indirectly regulates serum LDL cholesterol by destroying LDL receptors. In clinical studies, the main role of the proprotein convertase subtilisin/Kexin type9 (PCSK9) inhibitor in cholesterol regulation was elucidated. It is produced in the liver but is also present in the kidney and intestine. It prevents HMGCo from synthesizing cholesterol. SREBP-2 is a reductase that is induced by statins. In a dose-dependent manner, increasing SREBP-2 levels enhanced LDL-R and PCSK9 gene expression. At the minimum, two procedures have been developed to overcome the plasma level of PCSK9. This is the LDLR test, polyclonal antibodies, and sentience oligonucleotide. Lower dosage statin treatment with a proprotein convertase subtilisin/Kexin type9 inhibitor will be most efficient in lowering LDL and avoiding statin adverse effects. In multiple long-term trials, statins have been found to reduce cardiovascular mortality by 30% and stroke incidence by 20%. In this way, we conclude the role of PCSK9 in hypercholesterolemia.
REVIEW | doi:10.20944/preprints202109.0516.v1
Subject: Life Sciences, Microbiology Keywords: Tuberculosis; Mycobacterium tuberculosis; diabetes; hyperglycemia; dyslipidemia; cholesterol; triglycerides
Online: 30 September 2021 (14:01:44 CEST)
Diabetes is a major risk factor for tuberculosis (TB). Diabetes increases the risk of progression from latent tuberculosis infection (LTBI) to active pulmonary TB and TB patients with diabetes are at greater risk of more severe disease and adverse TB treatment outcomes compared to TB patients without co-morbidities. Diabetes is a complex disease characterized not only by hyperglycemia but also various forms of dyslipidemia. However, the relative contribution of these underlying metabolic factors to increased susceptibility to TB are poorly understood. This review summarizes our current knowledge on epidemiology and clinical manifestation of TB and diabetes comorbidity. We subsequently dissect the relative contribution of body mass index, hyperglycemia, elevated cholesterol and triglycerides on TB disease severity and treatment outcomes. Lastly, we discuss the impact of selected glucose and cholesterol lowering treatments frequently used in the management of diabetes on TB treatment outcomes.
ARTICLE | doi:10.20944/preprints202102.0350.v1
Subject: Life Sciences, Biochemistry Keywords: amidated alginate; tetrahydrolipstatin; fat; cholesterol; serum; liver; faeces
Online: 17 February 2021 (09:30:49 CET)
The effects of octadecylamide of alginic acid (amidated alginate) and tetrahydrolipstatin on serum and hepatic cholesterol, and the faecal output of fat and sterols were compared in rats. Amidated alginate is a sorbent of lipids, tetrahydrolipstatin is inhibitor of pancreatic lipase. Rats were fed diets containing cholesterol and palm fat at 10 and 70 g/kg, respectively. Palm fat was provided by coconut meal. Amidated alginate at 40 g/kg diet significantly decreased serum total cholesterol, LDL and hepatic cholesterol, hepatic lipids, and increased faecal output of fat and coprostanol. Tetrahydrolipstatin at 300 mg/kg diet significantly decreased LDL cholesterol, hepatic lipids and increased faecal output of fat. The intake of feed was not significantly influenced, however the weight gains in rats fed amidated alginate was lower than in rats of the control group. Both amidated alginate and tetrahydrolipstatin modified fatty acid profile in excreta lipids. Concentrations of saturated fatty acids were decreased and that of unsaturated fatty acids were increased. Despite different mode of action, amidated alginate and tetrahydrolipstatin were equally efficient in the removing dietary fat from the body.
HYPOTHESIS | doi:10.20944/preprints202101.0486.v1
Subject: Biology, Anatomy & Morphology Keywords: reproductive isolation; MEN; Hmr; Rab GTPases; cholesterol; HyMEN
Online: 25 January 2021 (11:39:44 CET)
At the end of mitosis the Mitotic Exit Network (MEN) pathway triggers complex tasks which mainly include the spindle disassembly and the nuclear envelopes assembly. In the course of telophase, which often lasts less than an hour and corresponds to only about 2% of the entire cell cycle’s duration, spatial and temporal cues are integrated to ensure that cytokinesis occurs after the genome has partitioned between mother and daughter cells. From the end of anaphase through telophase, sequential components of a Ras-like GTPase signaling pathway are controlled by a set of different spatial and temporal signals. Successful propagation of these signals through multi-step transduction requires a remarkable sequential coordination. By considering that cells lacking proper MEN function fail to exit from mitosis, I argue that in a hybrid genome impaired coordination between two diverged MENs is prone to result in critical mitotic defects, from late anaphase through telophase. The so-called HyMEN model of hybrid incompatibility depicted here can be regarded as an extension of the Bateson-Dobzhansky-Muller model of speciation, centered on the MEN.
Subject: Medicine & Pharmacology, Allergology Keywords: meta-analysis; chitosan; lifestyle-related disease; cholesterol lowering
Online: 18 November 2020 (10:59:37 CET)
This study presents a meta-analysis of studies that investigate the effectiveness of chitosan administration on lifestyle-related disease in murine models. A total of 34 published studies were used to evaluate the effect of chitosan supplementation. The effect sizes for various items after chitosan administration were evaluated using the standardized mean difference. Using Cochran’s Q test, the heterogeneity of effect sizes was assessed, after which a meta-ANOVA and –regression test was conducted to explain the heterogeneity of effect sizes using the mixed-effect model. Publication bias was performed using Egger’s linear regression test. Among the items evaluated, blood triglyceride and HDL-cholesterol showed the highest Q statistics and I2 values, respectively. Other than blood HDL-cholesterol, total cholesterol, and triglyceride in feces, most items evaluated showed a negative effect size with high significance in the fixed- and random-effect model (p<0.0001). In the meta-ANOVA and -regression test, administering chitosan and resistant starch was revealed to be most effective in lowering body weight. In addition, chitosan supplementation proved to be an effective solution for TNF-α inhibition. In conclusion, chitosan has been shown to be somewhat useful in improving symptoms of lifestyle-related disease. Although there are some limitations in the results of this meta-analysis due to the limited number of animal experiments conducted, chitosan administration nevertheless shows promise in enhancing the quality of human life.
REVIEW | doi:10.20944/preprints202005.0485.v1
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: aggression; cholesterol; impulsivity; lipids; neurobiology; suicide; suicidal behavior
Online: 31 May 2020 (17:44:27 CEST)
Previous incidental findings of an increase of suicidal risk among subjects with low cholesterol levels have drawn attention to the role of lipids in suicidal behavior. To date, multiple lines of evidence acquired from clinical studies have confirmed an association between low cholesterol levels and suicidal behavior, but the involvement of dimensional traits including impulsivity and aggression in this association remains elusive. In this narrative review, we aimed to address and synthesize the literature regarding the involvement of lipids in the neurobiology of suicidal behavior and its underlying psychological substrates, impulsivity and aggression. An electronic database search was performed using different combinations of relevant keywords. Both preclinical and clinical studies matching the scope of this article were reviewed and filtered through an inspection of the abstracts to recruit the most suitable articles that contributed essential and substantial findings to the literature. Although subject characteristics and study designs vary across studies, current research has demonstrated that impulsivity and aggression might have shared neurobiologic substrates involved in altered serotonergic neurotransmission. Despite the association between low serum lipid levels and suicidal behavior being well documented, the involvement of lipid subtypes in the pathophysiology of impulsive and aggressive traits remains elusive. Further work is warranted to recognize the roles of lipids in neuronal membrane functions and serotonin metabolism, promote a greater appreciation of identifying biomarkers that could be used to determine at-risk individuals, and develop potential interventions to disrupt the pathogenesis of behavioral phenotypes of suicide.
ARTICLE | doi:10.20944/preprints201907.0296.v1
Subject: Life Sciences, Biotechnology Keywords: point-of-care; cholesterol; clinical diagnostics; laboratory test
Online: 26 July 2019 (01:13:11 CEST)
Managing blood cholesterol levels is important for the treatment and prevention of diabetes, cardiovascular disease, and obesity. An easy-to-use, portable cholesterol blood test will accelerate more frequent testing by patients and at-risk populations. We aim to evaluate the performance of smartphone-based point-of-care cholesterol blood tests as compared to that of hospital-grade laboratory tests. We used smartphone systems that are already familiar to many people. Because smartphone systems can be carried around everywhere, blood can be measured easily and frequently. We compared the results of cholesterol tests with those of existing clinical diagnostic laboratory methods. We found that smartphone-based point-of-care lipid blood tests are as accurate as hospital-grade laboratory tests (N=116, R>0.97, P<0.001 for all 3 cholesterol blood tests: total cholesterol, high density lipoprotein, and triglyceride). Our system will be useful for those who need to manage blood cholesterol levels to motivate them to track and control their behavior.
REVIEW | doi:10.20944/preprints202107.0244.v1
Subject: Life Sciences, Biochemistry Keywords: P4-ATPase; ABC transporter; phospholipid; cholesterol; membranes; cellular signaling
Online: 12 July 2021 (11:24:18 CEST)
Lipid composition in the cellular membranes plays an important role in maintaining the struc-tural integrity of cells and in regulating cellular signaling that controls functions of both mem-brane-anchored and cytoplasmic proteins. ATP-dependent ABC and P4-ATPase lipid transport-ers, two integral membrane proteins, are known to contribute to lipid translocation across the li-pid bilayers on the cellular membranes. In this review, we will highlight current knowledge about the role of cholesterol and phospholipids of cellular membrane in regulating cell signaling and how lipid transporters participate this process.
ARTICLE | doi:10.20944/preprints202103.0161.v1
Subject: Life Sciences, Biochemistry Keywords: chicken eggs; quail eggs; fatty acids; iron; zinc; cholesterol
Online: 4 March 2021 (14:02:38 CET)
All over the world birds’ eggs are an important and valuable component of the human diet. The study aimed to compare the content of lipid components and their nutritional value as well as iron and zinc levels in chicken and quail eggs commonly available on the market. In egg lipids, unsaturated acids were dominated, especially oleic acid, the content of which was about 40% of total fatty acids (TFA). Linoleic acid was the major polyunsaturated fatty acid. Compared to other products of animal origin, eggs were characterized by favourable values of lipid quality indices, especially index of atherogenicity, thrombogenicity and hypocholesterolemic to hypercholesterolemic ratio. In the present study, no differences in the content of tested nutrients between eggs from different production methods (organic, free-range, barn, cages), as well as inter-breed differences were noticed. Cluster analysis showed that eggs enriched in n3 PUFA (according to producers’ declaration) differ from other groups of chicken eggs. However, only in eggs from one producer, the amount of EPA and DHA exceed 80 mg per 100 g, entitling to use the nutrition claim on the package. Quail eggs differed from chicken eggs in FA profile; they also had much higher iron and cholesterol levels.
Subject: Life Sciences, Biochemistry Keywords: Lipidomics; ssRNA+ virus; membrane fusion; lipid metabolism; cholesterol; sphingolipids; phosphatidylinositol
Online: 17 July 2020 (14:01:21 CEST)
Recent COVID-19 outbreak has come into prominence the pathogenetic mechanisms underlying the Biology and Biochemistry of viral infections. COVID-19 illness is brought about by infection with the severe acute respiratory syndrome coronavirus SARS-CoV-2 [1,2], an enveloped positive single stranded RNA virus (ssRNA+). From a lipidomics viewpoint, there is a variety of mechanisms involving virus infection that encompass virus entry, disturbance of host cell lipid metabolism, and the role played by diverse lipids in regard to the infection effectiveness. All these aspects have currently been tackled separately as independent issues and focusing on the function of proteins. Here we review the role of cholesterol and other lipids in in ssRNA+ and SARS-COV-2 infection.
ARTICLE | doi:10.20944/preprints202204.0085.v1
Subject: Chemistry, Food Chemistry Keywords: aflatoxin M1; milk; dairy; cholesterol; β-cyclodextrin; food safety; global warming
Online: 11 April 2022 (03:18:05 CEST)
Approximately one-third of mankind is chronically exposed to the carcinogenic aflatoxin M1 contained in milk and dairy products and there is no ready to use procedure for decontamination purposes applicable in milk technology. Since β-cyclodextrin is frequently used in food industry, its effect on aflatoxin M1 concentration was investigated during cholesterol removal. So, milk samples were spiked with aflatoxin M1 at the average level 0.89 µg/kg and cholesterol removal was carried out by 2.0% (w/w) β-cyclodextrin addition. As found, average cholesterol concentration decreased by 92.3% while aflatoxin M1 concentration decreased to 0.53 µg/kg, i. e. by 39.1% after the treatment. The procedure itself is easy, inexpensive, and ready to use in milk processing technology on current production lines without any investments, thus fully applicable with a high potential of full aflatoxin M1 milk decontamination efficiency and such way to strengthen considerably the food safety issues associated with milk and dairy products on global level.
ARTICLE | doi:10.20944/preprints202110.0329.v1
Subject: Earth Sciences, Environmental Sciences Keywords: perfluoroalkyl substances (PFAS); children; adolescents; lipid profile; cholesterol; generalized additive model
Online: 22 October 2021 (12:07:37 CEST)
Background: Residents of a large area of North-Eastern Italy were exposed for decades to high concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFAS) via drinking water. Despite the large amount of evidence in adults of a positive association between serum PFAS and metabolic outcomes, studies focusing on children and adolescents are limited. We evaluated the associations between serum PFAS concentrations and lipid profile, blood pressure and body mass index (BMI) in highly exposed adolescents and children. Methods: A cross-sectional analysis was conducted in 6669 adolescents (14-19 years) and 2693 children (8-11 years) enrolled in the health surveillance program of the Veneto Region. Non-fasting blood samples were obtained and analyzed for perfluorooctanoic acid (PFOA) perfluorooctane sulfonate (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), total cholesterol (TC) high-density lipoprotein cholesterol (HDL-C) and triglycerides. Low-density lipoprotein cholesterol (LDL-C) was calculated. Systolic and diastolic blood pressure (BP) were measured and BMI z-score accounting for age and sex was estimated. The associations between ln-transformed PFAS (and categorized into quartiles) and continuous outcomes were assessed using generalized additive models. Analyses were stratified by gender and adjusted for potential confounders. Results: Among adolescents, significant associations were detected between all investigated PFAS and TC, LDL-C, and to a fewer extent HDL-C. Among children, PFOS and PFNA had significant associations with TC, LDL-C and HDL-C, while PFOA and PFHxS had significant associations with HDL-C only. Increased serum concentrations of PFAS, particularly PFOS, were associated with decreased BMI z-score. No statistically significant associations were observed between PFAS concentrations and BP. Conclusions: Our study supports a consistent association between PFAS concentration and serum lipids, stronger for PFOS and PFNA and with a greater magnitude among children compared to adolescents, and a negative association of PFAS with BMI.
ARTICLE | doi:10.20944/preprints202008.0055.v1
Subject: Life Sciences, Biochemistry Keywords: IIAEK; IAP; photoaffinity labeling; click reaction; Caco-2 cells; cholesterol; ABCA1
Online: 3 August 2020 (00:14:52 CEST)
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.
ARTICLE | doi:10.20944/preprints201802.0185.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Plant sterols, wholegrain wheat, breakfast cereal, crossover clinical trial, LDL cholesterol
Online: 27 February 2018 (16:32:51 CET)
Meta-analysis of plant sterol supplement studies suggests an 8% lowering of LDL cholesterol for 2 to 2.5g/day of plant sterols. Cereal foods have been rarely tested and one study showed a lower LDL lowering of 5.4% with 1.6g of plant sterol in breakfast cereal. We aimed to test a breakfast wheat biscuit with 2g of plant sterols in a single serve of two wholegrain wheat breakfast cereal biscuits. Fifty volunteers with a total cholesterol of >5.5mmol/L were recruited for a randomised crossover study with two 4-week periods with no washout of which 45 successfully completed the study. After exclusion of four outliers the difference in LDL cholesterol between standard wholegrain wheat breakfast cereal biscuit and plant sterol-enriched wholegrain wheat breakfast cereal biscuit was 0.23 mmol/L or 5.6% (P=0.001) with a 95% confidence interval of 2.4-8.9%. Men and daily cereal consumers had greater responses 9.8% vs 3.6% and 7.2% vs 3.8% respectively (P<0.05). The LDL lowering effect of 2g of plant sterol enriched from one serve of wholegrain wheat breakfast cereal biscuit was not significantly different from other food products delivering 2-2.5g of plant sterols daily. Regular cereal consumers have a better response.
ARTICLE | doi:10.20944/preprints202010.0239.v1
Subject: Physical Sciences, Acoustics Keywords: KRas-4B; mutation; post-translational modification; HVR; anionic plasma membrane; signaling; cholesterol
Online: 12 October 2020 (12:31:28 CEST)
The Ras family of proteins is tethered to the inner leaflet of the cell membranes which play an essential role in signal transduction pathways that promote cellular proliferation, survival, growth, and differentiation. KRas-4B, the most mutated Ras isoform in different cancers, has been under extensive study for more than two decades. Here we have focused our interest on the influence of cholesterol on the orientations that KRas-4B adopts with respect to the plane of the anionic model membranes. How cholesterol in the bilayer might modulate preferences for specific orientation states is far from clear. Herein, after analyzing data from in total 4000 ns-long MD simulations for four KRas-4B systems, properties such as the area per lipid and thickness of the membrane as well as selected radial distribution functions, penetration of different moieties of KRas-4B, and internal conformational fluctuations of flexible moieties in KRas-4B have been calculated. It has been shown that high cholesterol content in the PM favors OS1, exposing the effector-binding loop for signal transduction in the cell from the atomic level. We confirm that high cholesterol in the PM helps KRas-4B mutant stay in its constitutively active state, which suggests that high cholesterol intake can increase mortality and may promote cancer progression for cancer patients. We propose that during the treatment of KRas-4B-related cancers, reducing the cholesterol level in the PM and sustaining cancer progression by controlling the plasma cholesterol intake might be taken into account in anti-cancer therapies.
REVIEW | doi:10.20944/preprints201906.0032.v1
Subject: Life Sciences, Molecular Biology Keywords: nucleic acids analogs, antisense, CRISPR, antibiotic resistance, myotonic dystrophy, cholesterol, hematologic malignancy,
Online: 5 June 2019 (08:11:12 CEST)
Oligonucleotides are key compounds widely used for research, diagnostics, and therapeutics. The rapid increase in oligonucleotide-based applications, together with the progress in nucleic acids research, led to the design of nucleotide analogs that when being part of these oligomers enhance their efficiency, bioavailability, or stability. One of the most useful nucleotide analogs are the first-generation bridge nucleic acids (BNA), also known as locked nucleic acids (LNA), which were used in combination with ribonucleotides, deoxyribonucleotides, or other analogs to construct oligomers with diverse applications. However, there is still room to improve their efficiency, bioavailability, stability, and, importantly, toxicity. A second generation BNA, BNANC (2'-O,4'-aminoethylene bridged nucleic acid), has been recently made available. Oligomers containing these analogs not only showed less toxicity when compared to LNA-containing compounds but in some cases also exhibited higher specificity. Although there are still few applications where BNANC-containing compounds were researched, the results are very promising warranting more efforts in incorporating these analogs for other applications. Furthermore, newer BNA compounds will be introduced in the near future offering great hope to oligonucleotide-based fields of research and applications.
ARTICLE | doi:10.20944/preprints202103.0205.v1
Subject: Life Sciences, Biochemistry Keywords: Niemann-Pick type C; soluble epoxide hydrolase; autophagy; cognitive decline; lifespan; inflammation; cholesterol; sphingolipids
Online: 5 March 2021 (21:48:31 CET)
Niemann-Pick type C (NPC) disease is a childhood autosomal recessive inherited rare neuro-degenerative disease, characterized by the accumulation of cholesterol and glycosphingolipids, implicating the autophagy-lysosome system. Inhibition of soluble epoxide hydrolase (sEH), an enzyme that metabolizes epoxy fatty acids (EpFAs) to 1,2-diols, exerts beneficial effects in mod-ulating inflammation and autophagy, critical features of the NPC disease. This study aimed to evaluate the effects of UB-EV-52 a sEH inhibitor (sEHi) in the Npc mouse model by administering for 4 weeks (5 mg/kg/day). Behavioral and cognitive assays (open field test (OF), elevated plus maze (EPM), novel object recognition test (NORT) and object location test (OLT) demonstrated that treatment produced an improvement in short- and long-term memory as well as in spatial memory. Moreover, the treatment with UB-EV-52 increased body weight and the lifespan by 25% and re-duced gene expression of the inflammatory markers (i.e. Il-1β and Mcp1) and improved oxidative stress (OS) markers (iNOS and Hmox1) in the treated Npc mice group. Regarding the autophagic markers, we surprisingly found significantly reduced levels of the ratio LC3B-II/LC3B-I and a significant reduction of brain protein levels of lysosomal-associated membrane protein-1 (LAMP-1) in Npc mice treated group compared to non-treated. Lipid profile analysis showed a significant reduction in lipid storage in the liver and some slight changes in brain tissue in treated Npc mice compared to non-treated groups. Thus, Our results suggest that the pharmacological inhibition of sEH ameliorates most of NPC’s characteristic traits in mice, demonstrating that sEH can be considered a potential therapeutic target for this condition.
REVIEW | doi:10.20944/preprints202010.0163.v1
Subject: Medicine & Pharmacology, Allergology Keywords: cholesterol; BMI; blood sugar; psychosis; LDL; HDL; antidepressants; antipsychotics; metabolism; metabolic abnormalities, platelet aggregation
Online: 8 October 2020 (09:03:41 CEST)
Patients with schizophrenia (SCZ) are at high risk of cardiovascular disease (CVD) due to an inherited predisposition, a sedentary life style and the use of antipsychotic medications. Several approaches have been taken to minimize this risk but results continue to be unsatisfactory. A potential alternative is prescribing Selective Serotonin Reuptake Inhibitors (SSRIs). SSRIs decrease platelet aggregation and reduce the risk of coronary heart disease in patients with depression. We therefore aim to investigate whether there is evidence that supports the use of SSRIs to reduce the risk for CVD in SCZ. A systematic review of the literature revealed five published reports relating to the impact of SSRIs on CV risk in SCZ. Three trials assessed the influence on metabolic parameters of fluvoxamine when combined with clozapine. Two of those studies found improvements with fluvoxamine. Of the other two reports, one indicates SSRIs as a group caused minimal but statistically significant increments in total cholesterol, LDL and triglyceride. The second report suggests that when SSRIs are combined with antipsychotics, the metabolic impact depends on the antipsychotic prescribed. While there are promising results, further studies are needed to establish the impact of SSRIs on CV risk in SCZ.
REVIEW | doi:10.20944/preprints201711.0137.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: almonds; lipids; heart disease; cardiovascular disease; nuts; dyslipidaemia; cholesterol; low density lipoprotein; high density lipoprotein
Online: 21 November 2017 (05:40:00 CET)
Background: Several preventive strategies to reduce dyslipidaemia, have been suggested of which dietary modification features as an important one. Addition of almonds in our daily diets has been proposed to beneficially impact the lipid profile. This review critically examines the available evidence assessing the effect of almonds on dyslipidaemia in the South Asian (particularly Indian) context. Methods: An extensive review comprising of epidemiological studies, clinical trials, meta-analyses and systematic reviews was conducted from published literature from across the world. Studies examining the effect of almonds on different aspects of dyslipidaemia viz. high LDL-C, low HDL-C, triglyceridaemia, high total cholesterol levels have been included. Results: Dyslipidaemia is a major risk factor for coronary heart disease and strategies to manage dyslipidaemia have been shown to reduce the incidence of CVD. Although there are proven pharmacological therapies to help manage this condition, there are not many nutritional interventions which can impact dyslipidaemia. Almonds have been shown to reduce LDL-C which is a known risk factor for CHD, in several studies and the effect of almonds has been well documented in systematic reviews and meta-analysis of clinical trials. Conclusions: Addition of almonds in the diet has been shown to not only to reduce LDL-C levels, but also to maintain HDL-C levels. This review informs about the use of this simple nutritional strategy which may help manage known major risk factors for heart disease such as high LDL-C and low HDL-C levels especially in the context of South Asians.
HYPOTHESIS | doi:10.20944/preprints202003.0340.v1
Subject: Biology, Other Keywords: coronavirus; SARS-CoV-2; lysosomal storage diseases; lipid rafts; cholesterol; angiotensin-converting enzyme-2 (ACE2); cathepsins
Online: 24 March 2020 (03:07:06 CET)
In the face of the newly emergent COVID-19 pandemic, researchers around the world are racing to identify efficacious drugs capable of preventing or treating its infection. They are doing that by testing already available and approved antimicrobials for their rapid repurposing against COVID-19. Using the data emerging on the comparable efficacy of various compounds having different mechanisms of action and indications, I suggest in this report, their potential mechanistic convergence. Specifically, I highlight the lysosome as a key possible therapeutic target for COVID-19, proposing one of the lysosomal storage disorders, Niemann-Pick type C disease (NPC), as a prototypical condition with inherent resistance or an “unfavorable” host cell environment for viral propagation. The included reasoning evolves from previously generated data in NPC, along with the emerging data on COVID-19. The aim of this report is to suggest that pharmacological induction of a “transient” NPC-like lysosomal dysfunction, could hold answers for targeting the ongoing COVID-19 pandemic.
ARTICLE | doi:10.20944/preprints201909.0309.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: val-phe-val-arg-asn (vfvrn); hypolipidemic effects; transintestinal cholesterol efflux (tice); 3t3-l1 preadipocyte; apoptosis
Online: 27 September 2019 (10:29:29 CEST)
Val-Phe-Val-Arg-Asn (VFVRN) has been identified and screened from lipid-lowering chickpea peptides (ChPs) by using a pharmacokinetic model in our previous experiment. The present study was conducted to investigate its effects and mechanisms on lipid metabolism. A high-fat diet C57BL/6J mice model and 3T3-L1 preadipocyte cell model were used. VFVRN was found to significantly decrease the levels of some blood lipids. The expressions of LDL receptor (LDLR), peroxisome proliferator-activated receptors (PPAR)α, liver X receptor (LXR)α, cholesterol 7α-hydroxylase (CYP7A1) and AMP-activated protein kinase (p-AMPK) in liver were up-regulated by VFVRN treatment. The expressions of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), fatty acid synthetase (FAS), 1-aminocyclopropane-1-carboxylate synthetase (ACC), sterol regulatory element-binding protein (SREBP)-1c and SREBP-2 in liver were significantly (P<0.05) down-regulated. Additionally, the expressions of PPARα and PPARγ in adipose tissues were up-regulated by VFVRN significantly (P<0.05). VFVRN might also contribute to transintestinal cholesterol efflux (TICE) by up-regulating the expressions of LXRα and ATP binding cassette G5/8 transporters (ABGC5/8). Moreover, VFVRN promoted 3T3-L1 preadipocyte apoptosis by up-regulating the expressions of BaX, cleaved Caspase-3 and down-regulating Bcl-2. VFVRN had potent effects in reversing metabolic disorders of blood and liver in a high-fat diet mice model, as well as to promote the apoptosis of 3T3-L1 preadipocytes.
ARTICLE | doi:10.20944/preprints201705.0166.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: constitutive androstene receptor; cytochrome P450, fibrosis; gender difference; high-fat-cholesterol (HFC) diet; necrosis; stroke-prone spontaneously hypertensive 5/Dmcr rats; sulfotransferase, pregnane X receptor; UGP-glucuronosyltransferase
Online: 23 May 2017 (07:54:46 CEST)
During middle age, women are less susceptible to nonalcoholic steatohepatitis (NASH) than men. Thus, we investigated the underlying molecular mechanisms behind these sexual differences using an established rat model of NASH. Mature female and male stroke-prone spontaneously hypertensive 5/Dmcr rats were fed control or high-fat-cholesterol (HFC) diets for 2, 8, and 14 weeks. Although HFC-induced hepatic fibrosis was markedly less severe in females than in males, only minor gender differences were observed in expression levels of cytochrome P450 enzymes (CYP)7A1, CYP8B1 CYP27A1, and CYP7B1, and multidrug resistance-associated protein 3, and bile salt export pump, which are involved in fibrosis-related bile acid (BA) kinetics. However, the BA detoxification-related enzymes UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) 2A1, and the nuclear receptors constitutive androstene receptor (CAR) and pregnane X receptor (PXR), were strongly suppressed in HFC fed males, and were only slightly changed in HFC-diet fed females. Expression levels of the farnesoid X receptor and its small heterodimer partner were similarly regulated in a gender-dependent fashion following HFC feeding. Hence, the pronounced female resistance to HFC-induced liver damage likely reflects sustained expression of the nuclear receptors CAR and PXR and the BA detoxification enzymes UGT and SULT.
ARTICLE | doi:10.20944/preprints201707.0033.v1
Subject: Medicine & Pharmacology, Gastroenterology Keywords: hepatic inflammation; high-fat-cholesterol diet; hypertension; mitogen-activated protein kinase; nonalcoholic steatohepatitis; nuclear factor erythroid 2-related factor 2 pathway; nuclear factor-kappa B; spontaneously hypertensive rat; stroke-prone spontaneously hypertensive5/Dmcr; Wistar Kyoto
Online: 14 July 2017 (10:54:38 CEST)
Populations with essential hypertension have a high risk of nonalcoholic steatohepatitis (NASH). In this study, we investigated the mechanism that underlies the progression of hypertension-associated NASH by comparing differences in the development of high fat and cholesterol (HFC) diet-induced NASH among three strains of rats, i.e., two hypertensive strains comprising spontaneously hypertensive rats and the stroke-prone spontaneously hypertensive 5/Dmcr, and the original Wistar Kyoto rats as the normotensive control. We investigated histopathological changes and molecular signals related to inflammation in the liver after feeding with the HFC diet for 8 weeks. The diet induced severe lobular inflammation and fibrosis in the livers of the hypertensive rats, whereas it only caused mild steatohepatitis in the normotensive rats. Increased activation of proinflammatory signaling (transforming growth factor-β1/mitogen-activated protein kinases pathway) was observed in the hypertensive strains fed with the HFC diet. In addition, the HFC diet suppressed the nuclear factor erythroid 2-related factor 2 pathway in the hypertensive rats and led to lower increases in the hepatic expression of heme oxygenase-1, which has anti-oxidative and anti-inflammatory activities. In conclusion, these signaling pathways might play crucial roles in the development of hypertension-associated NASH.