scholarly journals Pharmacological and fasting-induced activation of SIRT1/LXRα signaling alleviates diabetes-induced retinopathy

2019 ◽  
Author(s):  
Sandra S. Hammer ◽  
Cristiano P. Vieira ◽  
Delaney McFarland ◽  
Maximilian Sandler ◽  
Yan Levitsky ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Nutrient Sensing ◽  
Sirtuin 1 ◽  
Optokinetic Response ◽  
Diabetic Retina ◽  
Cholesterol Levels ◽  
Function Impairment ◽  
Effective Therapeutic Strategy ◽  
Neurovascular Damage

SummaryIn diabetes, the retina, a tissue with unique metabolic needs, demonstrates dysregulation of the intricate balance between nutrient availability and utilization. This results in cholesterol accumulation, pro-inflammatory and pro-apoptotic changes, and consequently neurovascular damage. Sirtuin 1 (SIRT1), a nutrient sensing deacetylase, is downregulated in the diabetic retina. In this study, the effect of SIRT1 stimulation by fasting or by pharmacological activation using SRT1720, was evaluated on retinal cholesterol metabolism, inflammation and neurovascular damage. SIRT1 activation, in retinal endothelial cells (REC) and neuronal retinal progenitor cells (R28), led to Liver X Receptor alpha (LXRα) deacetylation and subsequent increased activity, as measured by increased ATP-binding cassette transporter (ABC) A1 and G1 mRNA expression. In turn, increased cholesterol export resulted in decreased REC cholesterol levels. SIRT1 activation also led to decreased inflammation. SIRT1 activation, in vivo, prevented diabetes-induced inflammation and vascular and neural degeneration. Diabetes-induced visual function impairment, as measured by electroretinogram and optokinetic response, was significantly improved as a result of SIRT1 activation. Taken together, activation of SIRT1 signaling is an effective therapeutic strategy that provides a mechanistic link between the advantageous effects associated with fasting regimes and prevention of diabetic retinopathy (DR).

Cellular Cholesterol Modulates VEGFR-1 Function on Acute Leukemia Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1847-1847
Author(s):  
Rita Fragoso ◽  
Cristina Casalou ◽  
Sergio Dias
Keyword(s):  
Cell Migration ◽  
Growth Factor ◽  
Acute Leukemia ◽  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Leukemia Cell ◽  
Protein Translation ◽  
Leukemia Cells ◽  
Cholesterol Levels

Abstract Vascular endothelial growth factor (VEGF) and its receptors play a crucial role in malignancy and in disease, regulating the survival, proliferation, and migration of several cell types, such as endothelium and also leukemia cells. Following our recent report on the role of VEGFR-1 (FLT-1) in ALL (Fragoso R et al, 2006), in the present study we analyzed the molecular mechanisms whereby it modulates acute leukemia cell migration in response to VEGF/Placental Growth Factor (PLGF). First, we observed the formation of cell protrusions on ALL cells after VEGF/PLGF stimulation, with evidence for polymerized actin and FLT-1 co-localization (as determined by phalloidin, immunofluorescence staining, and confocal microscopy). Western blot analysis revealed that PLGF/VEGF stimulation resulted in increased RhoA and Rac1 GTPases expression. Co-treatment with LY200942 significantly decreased RhoA and Rac1 induction and cell migration by PLGF/VEGF, demonstrating this effect is modulated via Pi3 kinase. Next, we investigated the mechanisms whereby FLT-1 and actin co-localize at the cell “leading edge” (protrusions), after VEGF/PLGF stimulation, and the relevance of such co-localization for cell migration. We addressed this question by impairing the formation of lipid rafts/caveolae using drugs that either sequester (nystatin) or deplete (methyl-β-ciclodextrin) total cholesterol. Accordingly, co-treatment of leukemia cells with nystatin or MβCD and PLGF/VEGF blocked cell migration, an effect that was associated with a decrease in FLT-1 polarization and co-localization with actin filaments. Instead, FLT-1 was now found mostly in the cell cytosol. Given that leukemia cells have an increased rate of cholesterol up-take we sought to understand if increased cholesterol levels affected FLT-1 function in leukemia cells. Cholesterol repletion in leukemia cells enhanced leukemia cells migration in response to VEGF/PlGF (about 3 folds). This significant increase was associated with an increase in FLT-1 protein expression that, very interestingly, was particularly concentrated intracellulary in the cytoplasm. At this time we are trying to understand if this increase in FLT-1 expression after cholesterol repletion is associated with increase protein translation or impairment in proteasome activity. Finally, our preliminary in vivo experiments using Nod-Scid mice subjected (n=3) or not (n=3) to high fat diet (that results in increased cholesterol levels in the BM and in the spleen), showed this metabolic condition worsens disease symptoms and significantly decreases mouse survival. These results reveal for the first time some of the molecular mechanisms involved in FLT-1-mediated leukemia migration, namely the involvement of cholesterol metabolism, which may be crucial for new therapeutics delineation.

scholarly journals Identification of a novel cholesterol-lowering dipeptide, phenylalanine-proline (FP), and its down-regulation of intestinal ABCA1 in hypercholesterolemic rats and Caco-2 cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Arata Banno ◽  
Jilite Wang ◽  
Kenji Okada ◽  
Ryosuke Mori ◽  
Maihemuti Mijiti ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Protein Hydrolysate ◽  
Hdl Cholesterol ◽  
Atherogenic Index ◽  
Down Regulation ◽  
Potential Health ◽  
Cholesterol Lowering ◽  
Active Peptide ◽  
Cholesterol Levels

AbstractThere has been no report about in vivo active cholesterol-lowering dipeptide in any protein origin, despite their potential health benefits. Cattle heart protein hydrolysate ultra-filtrate (HPHU, molecular weight < ca. 1,000 Da peptide mixture) exhibits cholesterol-lowering activity in hypercholesterolemic rats, but the active peptide in HPHU that lowers serum cholesterol levels and its molecular mechanism are unknown. In this study, we separated and purified HPHU to identify a novel cholesterol-lowering dipeptide (phenylalanine-proline, FP) and characterized the mechanism underlying its effects in vivo and in vitro. We identified FP as an active peptide from HPHU by MALDI-TOF mass spectrometry. FP significantly decreased serum total and non-HDL cholesterol and hepatic cholesterol levels in rats. FP significantly increased serum HDL cholesterol, accompanied by a significant decrease in the atherogenic index. FP also significantly increased fecal cholesterol and acidic steroid excretion. Moreover, FP significantly decreased ATP-binding cassette transporter A1 (ABCA1) expression in the rat jejunum and reduced cholesterol absorption in Caco-2 cells. We found a novel cholesterol-lowering dipeptide FP that could improve cholesterol metabolism via the down-regulation of intestinal ABCA1. The cholesterol-lowering action induced by FP was disappeared in PepT1KO mice. FP-induced cholesterol-lowering action is mediated via PepT1 in mice.

scholarly journals Pro-Inflammatory Implications of 2-Hydroxypropyl-β-cyclodextrin Treatment

2021 ◽  
Vol 12 ◽  
Author(s):  
Tom Houben ◽  
Tulasi Yadati ◽  
Robbin de Kruijf ◽  
Marion J. J. Gijbels ◽  
Joost J. F. P. Luiken ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Lines ◽  
Cholesterol Metabolism ◽  
Strong Increase ◽  
Metabolic Inflammation ◽  
Cholesterol Levels ◽  
Short Term Exposure ◽  
Inflammatory Profile

Lifestyle- and genetically induced disorders related to disturbances in cholesterol metabolism have shown the detrimental impact of excessive cholesterol levels on a plethora of pathological processes such as inflammation. In this context, two-hydroxypropyl-β-cyclodextrin (CD) is increasingly considered as a novel pharmacological compound to decrease cellular cholesterol levels due to its ability to increase cholesterol solubility. However, recent findings have reported contra-indicating events after the use of CD questioning the clinical applicability of this compound. Given its potential as a therapeutic compound in metabolic inflammatory diseases, in this study, we evaluated the inflammatory effects of CD administration in the context of cholesterol-induced metabolic inflammation in vivo and in vitro. The inflammatory and cholesterol-depleting effects of CD were first investigated in low-density lipoprotein receptor knockout (Ldlr-/) mice that were transplanted with Npc1nih or Npc1wt bone marrow and were fed either regular chow or a high-fat, high-cholesterol (HFC) diet for 12 weeks, thereby creating an extreme model of lysosomal cholesterol-induced metabolic inflammation. In the final three weeks, these mice received daily injections of either control (saline) or CD subcutaneously. Subsequently, the inflammatory properties of CD were investigated in vitro in two macrophage cell lines and in murine bone marrow-derived macrophages (BMDMs). While CD administration improved cholesterol mobilization outside lysosomes in BMDMs, an overall pro-inflammatory profile was observed after CD treatment, evidenced by increased hepatic inflammation in vivo and a strong increase in cytokine release and inflammatory gene expression in vitro in murine BMDMs and macrophages cell lines. Nevertheless, this CD-induced pro-inflammatory profile was time-dependent, as short term exposure to CD did not result in a pro-inflammatory response in BMDM. While CD exerts desired cholesterol-depleting effects, its inflammatory effect is dependent on the exposure time. As such, using CD in the clinic, especially in a metabolic inflammatory context, should be closely monitored as it may lead to undesired, pro-inflammatory side effects.

scholarly journals TDP-43 mediates SREBF2-regulated gene expression required for oligodendrocyte myelination

2021 ◽  
Vol 220 (9) ◽  
Author(s):  
Wan Yun Ho ◽  
Jer-Cherng Chang ◽  
Kenneth Lim ◽  
Amaury Cazenave-Gassiot ◽  
Aivi T. Nguyen ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Homeostasis ◽  
Cholesterol Levels ◽  
The Central Nervous System ◽  
Cholesterol Supplementation ◽  
Regulated Gene Expression ◽  
Lateral Sclerosis

Cholesterol metabolism operates autonomously within the central nervous system (CNS), where the majority of cholesterol resides in myelin. We demonstrate that TDP-43, the pathological signature protein for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), influences cholesterol metabolism in oligodendrocytes. TDP-43 binds directly to mRNA of SREBF2, the master transcription regulator for cholesterol metabolism, and multiple mRNAs encoding proteins responsible for cholesterol biosynthesis and uptake, including HMGCR, HMGCS1, and LDLR. TDP-43 depletion leads to reduced SREBF2 and LDLR expression, and cholesterol levels in vitro and in vivo. TDP-43–mediated changes in cholesterol levels can be restored by reintroducing SREBF2 or LDLR. Additionally, cholesterol supplementation rescues demyelination caused by TDP-43 deletion. Furthermore, oligodendrocytes harboring TDP-43 pathology from FTD patients show reduced HMGCR and HMGCS1, and coaggregation of LDLR and TDP-43. Collectively, our results indicate that TDP-43 plays a role in cholesterol homeostasis in oligodendrocytes, and cholesterol dysmetabolism may be implicated in TDP-43 proteinopathies–related diseases.

scholarly journals Anti-Oxidant and Anti-Hypercholesterolemic Activities ofWasabia japonica

2010 ◽  
Vol 7 (4) ◽  
pp. 459-464 ◽  
Author(s):  
Young Sun Lee ◽  
Jae Ha Yang ◽  
Man Jong Bae ◽  
Wang Keun Yoo ◽  
Shen Ye ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Normal Diet ◽  
High Cholesterol Diet ◽  
Inos Mrna ◽  
No Production ◽  
Sprague Dawley ◽  
Cholesterol Levels ◽  
Anti Oxidant

The effects ofWasabia japonica(WJ) were investigatedin vitroandin vivofor their anti-oxidant and anti-hypercholesterolemic activities. It was found that the aqueous extracts of WJ leaves (WJL) had strong scavenging activities towards 1,1-Diphenyl-2-picryhydrazyl (DPPH) and nitric oxide (NO) free radicals in cell free systems. WJL also inhibited NO production and the expressions of inducible NO synthase (iNOS) mRNA and enzyme protein, determined by Griess reactions, RT-PCR or Western blotting respectively in Lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages cells. The anti-hypercholesterolemic effects of WJ diet were investigated in hypercholesterolemia rats. Sprague-Dawley rats were divided into four groups and were fed with either normal diet (Group 1), or diet containing 1%(w/w) cholesterol (Groups 2, 3 and 4). After 4 weeks, Group 2 was changed to normal diet, Groups 3 and 4 were changed to the diet containing 5% WJ leaf and or 5% WJ root, respectively. 3 weeks after WJ diets, Serum HDL-cholesterol levels were significantly increased in WJ diet groups compared with the normal diet hypercholesterolemia rats. In contrast, the serum LDL-cholesterol levels and liver xanthine oxidase (XO) activity in WJ diet groups were significantly decreased. The results indicate that the WJ extracts have significant anti-oxidant activities, and the WJ diet exhibited anti-hypercholesterolemic action in high cholesterol diet rats, which was companied with modulations of cholesterol metabolism and decrease in liver XO activity.

Certain aspects of cholesterol metabolism and hepatic protein synthesis in the rat

1964 ◽  
Vol 207 (6) ◽  
pp. 1287-1294 ◽  
Author(s):  
Shiro Saito ◽  
Louis Charles Fillios
Keyword(s):  
Protein Synthesis ◽  
Cholesterol Metabolism ◽  
Dietary Treatment ◽  
High Serum ◽  
Liver Protein ◽  
High Serum Cholesterol ◽  
Cholesterol Levels ◽  
Hepatic Protein Synthesis

Hepatic protein synthesis was studied in rats fed a hypercholesteremic diet, containing cholesterol and cholic acid, and high in fat. If such a diet was fed for periods of at least 4 weeks a lowered capacity of amino acid incorporation into liver protein in vivo and in vitro was observed. The animals selected were rats which had been previously characterized by such a dietary assay as being neither refractory nor susceptible to induction of high serum cholesterol levels. When "hypo-responders" (i.e., rats which are relatively refractory to hypercholesteremia) were compared to "hyper-responders" significant differences in protein synthesis in vivo were observed after only 2 weeks of dietary treatment; the capacity for incorporation of amino acids in the livers of hyper-responders was significantly lower than that in the hypo-responders. Several studies were also carried out in vitro including an attempt to determine which intracellular components of the liver may be affected; it appears that the defect(s) is primarily related to the endoplasmic reticulum. Thus, diet may act as the modus operandi for revealing any purported inherent defect(s).

Abstract 344: Bcl-x Inactivation in Macrophages Accelerates Progression of Advanced Atherosclerotic Lesions in Apoe -/- Mice

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Philippe Lesnik ◽  
Virginie Deswaerte ◽  
Emmanuel L Gautier ◽  
Flora Saint-Charles ◽  
John Pirault ◽  
...  
Keyword(s):  
Atherosclerotic Plaque ◽  
Cholesterol Metabolism ◽  
Apoptotic Cell ◽  
Atherosclerotic Lesion ◽  
The Body ◽  
Plaque Progression ◽  
Atherosclerotic Lesions ◽  
Cholesterol Levels ◽  
Macrophage Apoptosis

Background: Bcl-x is the most abundantly expressed member of the Bcl-2 gene family in macrophages but its role in macrophage apoptosis during atherogenesis is unknown. Methods and results: We previously reported dual pro- and anti-atherogenic effects of macrophage survival in early versus advanced atherosclerotic lesions respectively, potentially reflecting growing impairment of efferocytosis during plaque progression. Here, we specifically inactivated Bcl-x in macrophages and evaluated its impact on atherosclerotic lesion formation in Apoe -/- mice at various stages of the disease. Bcl-x deficiency in macrophages increased susceptibility to apoptosis, resulting in the depletion of tissue macrophages in vivo, including its major pool, Küppfer cells in the liver. We also observed increased cholesterol levels, that was however not associated with any acceleration of early atherosclerotic plaque progression. This observation, suggests that the atheroprotective effect of macrophage apoptosis at that stage of disease was counterbalanced by enhanced cholesterol levels. Bcl-x KOmac/Apoe -/- mice exhibited significantly larger advanced lesions than control mice. These lesions showed vulnerable traits. Such enhanced lesion size may occur as a result not only of apoptotic cell accumulation but also of elevated cholesterol levels. Conclusions: Modulation of macrophage resistance to apoptosis through targeted deletion of Bcl-x has a major impact on the entire macrophage cell population in the body, including Küpffer cells. Macrophage survival may, therefore, not only influence atherosclerotic plaque development and vulnerability but also cholesterol metabolism.

scholarly journals Oats Containing 1.4g β-Glucan Significantly Increased Lactobacillus Levels In Vitro using M-SHIME® Model and In Vivo in Healthy Adults with Elevated Cholesterol Levels

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1567-1567
Author(s):  
Alison Kamil ◽  
Lisa Fleige ◽  
YiFang Chu ◽  
Peter John De Chavez ◽  
Cindy Duysburgh ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Study Design ◽  
Cholesterol Metabolism ◽  
Preliminary Evidence ◽  
Healthy Adults ◽  
Cholesterol Levels ◽  
Elevated Cholesterol ◽  
Vitro Effect

Abstract Objectives Preliminary evidence, primarily animal and in vitro studies, suggests that oats selectively impact the microbiota. We conducted an in vitro screening trial, using the M-SHIME model®, with fecal inoculum from healthy adult donors with elevated cholesterol levels to determine the effect of 1 serving (40g) of Quaker Old-Fashioned Oats (OFO) containing 1.4g β-Glucan (βG). We also conducted a clinical trial to confirm the in vitro effect of OFO in vivo using fecal material obtained from a similar subject population. Methods In Vitro Trial- Validated M-SHIME model of the entire GI system was used with mucosal beads. Fecal inoculum was donated from 3 healthy adults with elevated cholesterol levels (total cholesterol &gt;5.5 to &lt; 7mmol/L and LDL cholesterol &gt;3.4 to ≤ 4.9mmol/L). Treatment was 40g OFO, containing 1.4g βG. Study design included 2 week (wk) stabilization, 2 wk control, and 3 wk intervention periods. Clinical Trial- Randomized, single-blind, placebo-controlled, cross-over study with 38 healthy adults with elevated cholesterol levels within same ranges used in vitro. Treatment was 40g OFO (1.4g βG). Control was 40g Cream of Rice, containing no βG. Study design included 2 wk run-in, 6 wk intervention, and 4 wk wash out periods. Changes in select fecal groups were quantified using qPCR. Results OFO statistically increased lactobacillus in vitro in all colon regions and in vivo compared to control. OFO statistically increased bifidobacterium in vitro in all colon regions compared to control. Increase in bifidobacterium in vivo was observed but did not reach significance. No significant changes in either studies for other bacteria's quantified: Akkermansia Muciniphila, Enterobacteriaceae, Roseburia, Faecalibacterium Prausnitzii, Clostridium Perfringens, and Eubacterium Hallii. Conclusions 1 serving of OFO significantly increased lactobacillus levels in vitro and was replicated in vivo. This is notable because previous in vivo research suggests lactobacillus strains may play a significant role in cholesterol metabolism, and therefore this effect warrants further study in humans. Funding Sources Financial support for this study was provided by PepsiCo, Inc. The views expressed in this abstract are those of the authors and do not necessarily reflect the position or policy of PepsiCo, Inc.

Platelet Aggregation in Diabetes Mellitus and the Effect of Insulin in Vivo on Aggregation

1972 ◽  
Vol 27 (01) ◽  
pp. 114-120 ◽  
Author(s):  
A. A Hassanein ◽  
Th. A El-Garf ◽  
Z El-Baz
Keyword(s):  
Platelet Aggregation ◽  
Rapid Onset ◽  
Control Group ◽  
Diabetic Patients ◽  
Fasting State ◽  
Clotting Time ◽  
Cholesterol Levels ◽  
Platelet Disaggregation ◽  
Aggregation And Disaggregation

SummaryADP-induced platelet aggregation and calcium-induced platelet aggregation tests were studied in 14 diabetic patients in the fasting state and half an hour after an intravenous injection of 0.1 unit insulin/kg body weight. Platelet disaggregation was significantly diminished as compared to a normal control group, and their results were negatively correlated with the corresponding serum cholesterol levels. Insulin caused significant diminution in the ADP-induced platelet aggregation as a result of rapid onset of aggregation and disaggregation. There was also a significant increase in platelet disaggregation. In the calcium-induced platelet aggregation test, there was a significant shortening of the aggregation time, its duration, and the clotting time. The optical density fall due to platelet aggregation showed a significant increase. Insulin may have a role in correcting platelet disaggregation possibly through improvement in the intracellular enzymatic activity.

Sign in / Sign up

Export Citation Format

Share Document