scholarly journals (Phospho)proteomic Profiling of Microsatellite Unstable CRC Cells Reveals Alterations in Nuclear Signaling and Cholesterol Metabolism Caused by Frameshift Mutation of NMD Regulator UPF3A

2020 ◽  
Vol 21 (15) ◽  
pp. 5234 ◽  
Author(s):  
Malwina Michalak ◽  
Eva-Maria Katzenmaier ◽  
Nina Roeckel ◽  
Stefan M. Woerner ◽  
Vera Fuchs ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Repetitive Sequences ◽  
Regulation Of Gene Expression ◽  
Colorectal Adenomas ◽  
Proteomic Profiling ◽  
Frameshift Mutations ◽  
Dna Mismatch ◽  
Nonsense Mediated Rna Decay

DNA mismatch repair-deficient colorectal cancers (CRCs) accumulate numerous frameshift mutations at repetitive sequences recognized as microsatellite instability (MSI). When coding mononucleotide repeats (cMNRs) are affected, tumors accumulate frameshift mutations and premature termination codons (PTC) potentially leading to truncated proteins. Nonsense-mediated RNA decay (NMD) can degrade PTC-containing transcripts and protect from such faulty proteins. As it also regulates normal transcripts and cellular physiology, we tested whether NMD genes themselves are targets of MSI frameshift mutations. A high frequency of cMNR frameshift mutations in the UPF3A gene was found in MSI CRC cell lines (67.7%), MSI colorectal adenomas (55%) and carcinomas (63%). In normal colonic crypts, UPF3A expression was restricted to single chromogranin A-positive cells. SILAC-based proteomic analysis of KM12 CRC cells revealed UPF3A-dependent down-regulation of several enzymes involved in cholesterol biosynthesis. Furthermore, reconstituted UPF3A expression caused alterations of 85 phosphosites in 52 phosphoproteins. Most of them (38/52, 73%) reside in nuclear phosphoproteins involved in regulation of gene expression and RNA splicing. Since UPF3A mutations can modulate the (phospho)proteomic signature and expression of enzymes involved in cholesterol metabolism in CRC cells, UPF3A may influence other processes than NMD and loss of UPF3A expression might provide a growth advantage to MSI CRC cells.

scholarly journals Abnormal brain cholesterol homeostasis in Alzheimer’s disease—a targeted metabolomic and transcriptomic study

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vijay R. Varma ◽  
H. Büşra Lüleci ◽  
Anup M. Oommen ◽  
Sudhir Varma ◽  
Chad T. Blackshear ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Tissue ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Homeostasis ◽  
Transcriptomic Data ◽  
Brain Cholesterol ◽  
Cholesterol Levels

AbstractThe role of brain cholesterol metabolism in Alzheimer’s disease (AD) remains unclear. Peripheral and brain cholesterol levels are largely independent due to the impermeability of the blood brain barrier (BBB), highlighting the importance of studying the role of brain cholesterol homeostasis in AD. We first tested whether metabolite markers of brain cholesterol biosynthesis and catabolism were altered in AD and associated with AD pathology using linear mixed-effects models in two brain autopsy samples from the Baltimore Longitudinal Study of Aging (BLSA) and the Religious Orders Study (ROS). We next tested whether genetic regulators of brain cholesterol biosynthesis and catabolism were altered in AD using the ANOVA test in publicly available brain tissue transcriptomic datasets. Finally, using regional brain transcriptomic data, we performed genome-scale metabolic network modeling to assess alterations in cholesterol biosynthesis and catabolism reactions in AD. We show that AD is associated with pervasive abnormalities in cholesterol biosynthesis and catabolism. Using transcriptomic data from Parkinson’s disease (PD) brain tissue samples, we found that gene expression alterations identified in AD were not observed in PD, suggesting that these changes may be specific to AD. Our results suggest that reduced de novo cholesterol biosynthesis may occur in response to impaired enzymatic cholesterol catabolism and efflux to maintain brain cholesterol levels in AD. This is accompanied by the accumulation of nonenzymatically generated cytotoxic oxysterols. Our results set the stage for experimental studies to address whether abnormalities in cholesterol metabolism are plausible therapeutic targets in AD.

scholarly journals Human Lanosterol 14-Alpha Demethylase (CYP51A1) Is a Putative Target for Natural Flavonoid Luteolin 7,3′-Disulfate

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2237
Author(s):  
Leonid Kaluzhskiy ◽  
Pavel Ershov ◽  
Evgeniy Yablokov ◽  
Tatsiana Shkel ◽  
Irina Grabovec ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Clinical Importance ◽  
Optical Biosensor ◽  
Water Soluble ◽  
Soluble Form ◽  
Redox Partner ◽  
Access Channel ◽  
Kd Values ◽  
Key Steps

Widespread pathologies such as atherosclerosis, metabolic syndrome and cancer are associated with dysregulation of sterol biosynthesis and metabolism. Cholesterol modulates the signaling pathways of neoplastic transformation and tumor progression. Lanosterol 14-alpha demethylase (cytochrome P450(51), CYP51A1) catalyzes one of the key steps in cholesterol biosynthesis. The fairly low somatic mutation frequency of CYP51A1, its druggability, as well as the possibility of interfering with cholesterol metabolism in cancer cells collectively suggest the clinical importance of CYP51A1. Here, we show that the natural flavonoid, luteolin 7,3′-disulfate, inhibits CYP51A1 activity. We also screened baicalein and luteolin, known to have antitumor activities and low toxicity, for their ability to interact with CYP51A1. The Kd values were estimated using both a surface plasmon resonance optical biosensor and spectral titration assays. Unexpectedly, in the enzymatic activity assays, only the water-soluble form of luteolin—luteolin 7,3′-disulfate—showed the ability to potently inhibit CYP51A1. Based on molecular docking, luteolin 7,3′-disulfate binding suggests blocking of the substrate access channel. However, an alternative site on the proximal surface where the redox partner binds cannot be excluded. Overall, flavonoids have the potential to inhibit the activity of human CYP51A1 and should be further explored for their cholesterol-lowering and anti-cancer activity.

scholarly journals The effect of amino-acid-supplemented wheat gluten on cholesterol metabolism in the rat

1985 ◽  
Vol 53 (1) ◽  
pp. 25-30 ◽  
Author(s):  
M. Bassat ◽  
S. Mokady
Keyword(s):  
Amino Acid ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Wheat Gluten ◽  
Blood Cholesterol ◽  
Amino Acid Supplementation ◽  
Faecal Excretion ◽  
Weanling Rats ◽  
Low Levels

1. The effect of lysine- and threonine-supplemented wheat gluten on cholesterol metabolism was studied using male weanling rats. Animals were fed on cholesterol-free diets containing 100 or 200 g gluten/kg with or without amino acid supplementation, and compared with animals given 50, 100 and 200 g casein/kg diets, for 3 weeks.2. A hypocholesterolaemic effect observed with the wheat gluten-fed rats, compared with the animals given 100 and 200 g casein/kg diets, was accompanied by increased turnover of cholesterol as expressed by enhanced cholesterol biosynthesis and increased faecal excretion of cholesterol and bile acids. This effect was not abolished by lysine and threonine supplementation.3. Low levels of blood cholesterol were also observed in the rats fed on the 50 g casein/kg diet. However, a different mechanism, related to impairment of cholesterol transport from the liver, was most likely responsible for the hypocholesterolaemia found in these protein-malnourished animals.4. The effect on cholesterol metabolism produced by dietary wheat gluten was independent of the low quality of the protein and of its specific deficiency in lysine and threonine.

TAMI-62. METHIONINE METABOLISM CLOSELY RELATED WITH SELF-RENEW, PLURIPOTENCY AND CELL DEATH IN GICS THROUGH MODIFICATION OF CHOLESTEROL BIOSYNTHESIS, RIBOSOMAL RNA AND AUTOPHAGY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi211-vi211
Author(s):  
Kiyotaka Yokogami ◽  
Hideo Takeshima
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Ribosomal Rna ◽  
Cell Activation ◽  
Cultured Cells ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Dna Demethylation ◽  
Methionine Metabolism ◽  
Starting Point

Abstract Glioma initiating cells (GICs) are the source of glioma cells that have the ability to self-renew and pluripotency, which are treatment-resistant, starting point for relapse and eventual death despite multimodality therapy. Since high accumulation is observed in 11cMet-PET at the time of recurrence, it is important to understand the mechanism of tumor cell activation caused by the reorganization of methionine metabolism. We cultured cells in methionine-deprived culture medium and performed a comprehensive analysis, and found that methionine depletion markedly decreased proliferation and increasing cell death of GICs. Decreased SAM, which is synthesized intracellularly catalyzed by methionine adenosyltransferase (MAT) using methionine, triggered the following: (i) global DNA demethylation, (ii) hyper-methylation of signaling pathways regulating pluripotentcy of stem cells, (iii) decreased expression of the core-genes and pluripotent marker of stem cells, (iv) decreased cholesterol synthesis and increased excretion mainly through decreased SREBF2 and FOXM1, (v) down-regulation of the large subunit of ribosomal protein configured 28S and ACA43, snoRNA guiding the pseudouridylation of 28S ribosomal RNA, which has crucial role for translation and (vi) possible connection between methionine metabolism and pluripotency, protein synthesis through cholesterol metabolism: SREBF2-FOXM1 and ACA43 axis, respectively. (vii) Disruption of autophagy by insufficient formation of macroautophagosomes. In conclusion, methionine metabolism closely related with self-renew, pluripotency and cell death in GICs through modification of cholesterol biosynthesis, ribosomal RNA and autophagy.

scholarly journals Impaired cholesterol metabolism in the mice model of cystic fibrosis. A vicious circle?

2019 ◽  
Author(s):  
Felice Amato ◽  
Alice Castaldo ◽  
Giuseppe Castaldo ◽  
Gustavo Cernera ◽  
Gaetano Corso ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Absorption ◽  
Vicious Circle ◽  
Liver Cholesterol ◽  
Mice Model ◽  
Hepatic Expression ◽  
Expression Of Genes ◽  
Low Cholesterol

AbstractPatients with cystic fibrosis (CF) have low cholesterol absorption and, despite enhanced endogenous biosynthesis, low serum cholesterol. Herein, we investigated cholesterol metabolism in a murine CF model in comparison to wild type (WT) testing serum and liver surrogate biomarkers together with the hepatic expression of genes involved in cholesterol metabolism. CF mice display lower sterols absorption and increased endogenous biosynthesis. Subsequently, we evaluated the effects of a cholesterol-supplemented diet on cholesterol metabolism in CF and WT mice. The supplementation in WT mice determines biochemical changes similar to humans. Instead, CF mice with supplementation did not show significant changes, except for serum phytosterols (−50%), liver cholesterol (+35%) and TNFα mRNA expression, that resulted 5-fold higher than in CF without supplementation. However, liver cholesterol in CF mice with supplementation resulted significantly lower compared to WT supplemented mice. This study shows that in CF mice there is a vicious circle in which the altered bile salts synthesis/secretion contribute to reduce cholesterol digestion/absorption. The consequence is the enhanced liver cholesterol biosynthesis that accumulates in the cell triggering inflammation.

scholarly journals Dysregulated Bile Acid Receptor-mediated Signaling and IL-17A Induction are Implicated in Diet-associated Hepatic Health and Cognitive Function

2020 ◽  
Author(s):  
PRASANT KUMAR JENA ◽  
Lili Sheng ◽  
Michelle Nguyen ◽  
Jacopo Di Lucente ◽  
Ying Hu ◽  
...  
Keyword(s):  
Cognitive Function ◽  
Gut Microbiota ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Control Diet ◽  
Hepatic Metabolism ◽  
Long Term Potentiation ◽  
Nonalcoholic Fatty Liver ◽  
Term Potentiation ◽  
Diet Intake

Abstract Background: Chronic consumption of high sugar and high fat diet associated with liver inflammation and cognitive decline. This paper tests a hypothesis that the development and resolution of diet-induced nonalcoholic fatty liver disease (NAFLD) has an impact on neuroplasticity and cognition. Methods: C57BL/6 wild-type mice were fed with either a healthy control diet (CD) or a fructose, palmitate, and cholesterol (FPC)-enriched diet since weaning. When mice were 3-months old, FPC diet-fed mice were randomly assigned to receive either FPC-enriched diet with or without 6% inulin supplementation. At 8 months of age, all three groups of mice were euthanized followed by analysis of inflammatory signaling in the liver and brain, gut microbiota, and cecal metabolites. Results: Our data showed that FPC diet intake induced hepatic steatosis and inflammation in the liver and brain along with elevated RORγ and IL-17A signaling. Accompanied by microglia activation and reduced hippocampal long-term potentiation, FPC diet intake also reduced postsynaptic density-95 and brain derived neurotrophic factor, whereas inulin supplementation prevented diet-reduced neuroplasticity and the development of NAFLD. In the gut, FPC diet increased Coriobacteriaceae and Erysipelotrichaceae, which are implicated in cholesterol metabolism, and the genus Allobaculum, and inulin supplementation reduced them. Furthermore, FPC diet reduced FXR and TGR5 signaling, and inulin supplementation reversed these changes. Untargeted cecal metabolomics profiling uncovered 273 metabolites, and 104 had significant changes due to FPC diet intake or inulin supplementation. Among the top 10 most affected metabolites, FPC-fed mice had marked increase of zymosterol, a cholesterol biosynthesis metabolite, and reduced 2,8-dihydroxyquinoline, which has known benefits in reducing glucose intolerance; these changes were reversible by inulin supplementation. Additionally, the abundance of Barnesiella, Coprobacter, Clostridium XIVa, and Butyrivibrio were negatively correlated with FPC diet intake and the concentration of cecal zymosterol but positively associated with inulin supplementation, suggesting their benefits. Conclusion: Taken together, the presented data suggest that diet alters the gut microbiota and their metabolites, including bile acids. This will subsequently affect IL-17A signaling, resulting in systemic impacts on both hepatic metabolism and cognitive function.

scholarly journals Proteomic Profiling Reveals the Molecular Changes of Insomnia Patients

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Guanying Wang ◽  
Xiaojuan Ren ◽  
Xingping Zhang ◽  
Qingquan Wang ◽  
Tao Liu ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Sleep Onset ◽  
Public Health Problem ◽  
Sleep Time ◽  
Control Group ◽  
Proteomic Profiling ◽  
Ppi Network ◽  
Metabolic Systems ◽  
Hub Proteins

Background. Insomnia is an economic burden and public health problem. This study is aimed at exploring potential biological pathways and protein networks for insomnia characterized by wakefulness after sleep. Method. Proteomics analysis was performed in the insomnia group with wakefulness and the control group. The differentially expressed proteins (DEPs) were enriched; then, hub proteins were identified by protein-protein interaction (PPI) network and verified by parallel reaction monitoring (PRM). Results. Compared with the control group, the sleep time and efficiency of insomnia patients were decreased, and awakening time and numbers after sleep onset were significantly increased ( P < 0.001 ). The results of proteomic sequencing found 68 DEPs in serum under 1.2-fold changed standard. These DEPs were significantly enriched in humoral immune response, complement and coagulation cascades, and cholesterol metabolism. Through the PPI network, we identified 10 proteins with the highest connectivity as hub proteins. Among them, the differential expression of 9 proteins was verified by PRM. Conclusion. We identified the hub proteins and molecular mechanisms of insomnia patients characterized by wakefulness after sleep. It provided potential molecular targets for the clinical diagnosis and treatment of these patients and indicated that the immune and metabolic systems may be closely related to insomnia characterized by wakefulness after sleep.

scholarly journals RNAs as proximity labeling media for identifying nuclear speckle positions relative to the genome

2018 ◽  
Author(s):  
Weizhong Chen ◽  
Zhangming Yan ◽  
Simin Li ◽  
Norman Huang ◽  
Xuerui Huang ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Genomic Sequence ◽  
Single Cells ◽  
Regulation Of Gene Expression ◽  
Nuclear Genome ◽  
Fold Increase ◽  
Nuclear Speckles ◽  
Nuclear Speckle ◽  
Interaction Sites ◽  
Genomic Regions

AbstractNuclear speckles are interchromatin structures enriched in RNA splicing factors. Determining their relative positions with respect to the folded nuclear genome could provide critical information on co-and post-transcriptional regulation of gene expression. However, it remains challenging to identify which parts of the nuclear genome are in proximity to nuclear speckles, due to physical separation between nuclear speckle cores and chromatin. We hypothesized that noncoding RNAs including small nuclear RNAs, 7SK and Malat1, which accumulate at the periphery of nuclear speckles (nsaRNA,nuclearspeckleassociated RNA), may extend to sufficient proximity to the nuclear genome. Leveraging a transcriptome-genome interaction assay (MARGI), we identified nsaRNA-interacting genomic sequences, which exhibited clustering patterns (nsaPeaks) in the genome, suggesting existence of relatively stable interaction sites for nsaRNAs in nuclear genome. Posttranscriptional pre-mRNAs, which are known to be clustered to nuclear speckles, exhibited proximity to nsaPeaks but rarely to other genomic regions. Furthermore, CDK9 proteins that localize to the vicinity of nuclear speckles produced ChIP-seq peaks that overlapped with nsaPeaks. Our combined DNA FISH and immunofluorescence analysis in 182 single cells revealed a 3-fold increase in odds for nuclear speckles to localize near an nsaPeak than its neighboring genomic sequence. These data suggest a model that nsaRNAs locate in sufficient proximity to nuclear genome and leave identifiable genomic footprints, thus revealing the parts of genome proximal to nuclear speckles.

Gender effects of tall oil versus soybean phytosterols as cholesterol-lowering agents in hamsters

1998 ◽  
Vol 76 (7-8) ◽  
pp. 780-787 ◽  
Author(s):  
Fady Y Ntanios ◽  
Diane E MacDougall ◽  
Peter JH Jones
Keyword(s):  
Total Cholesterol ◽  
Cholesterol Level ◽  
Cholesterol Metabolism ◽  
Total Cholesterol Level ◽  
Cholesterol Biosynthesis ◽  
Gender Effects ◽  
Plasma Total Cholesterol ◽  
Tall Oil ◽  
Cholesterol Lowering ◽  
Plasma Total Cholesterol Level

To examine the effect of gender on the mechanisms of action of phytosterols extracted from tall oil (TO) and soybean (SB) on cholesterol and phytosterol metabolism, male and female hamsters were fed cholesterol-enriched diets containing 0.5 or 1% (w/w) TO or SB phytosterols for 90 days. Plasma lipoprotein cholesterol profile and tissue phytosterol and cholesterol biosynthesis levels were determined. Mean plasma total-cholesterol level in females fed 1% (w/w) SB was reduced (p < 0.05) by 44%, while in males it was lowered (p < 0.05) by 25% compared with their respective controls. Moreover, mean plasma total-cholesterol level was reduced (p < 0.05) in male hamsters by -31% and female hamsters by -32% when fed 1% (w/w) TO. Cholesterol biosynthesis was higher (p < 0.05) by twofold in groups fed TO at 0.5 and 1% (w/w) concentrations, compared with SB. Hamsters fed TO at 0.5 and 1% (w/w) levels also had higher (p < 0.05) hepatic and enterocytic campesterol contents than SB-fed animals. These findings demonstrate gender differences in cholesterol metabolism in TO- and SB-fed hamsters. The results suggest that TO, conversely to SB phytosterol, is a more effective cholesterol-lowering agent in male, but not as much in female, hamsters, over a feeding period of 90 days.Key words: phytosterols, cholesterol, sitosterol, sitostanol, gender, hamster.

scholarly journals Intron and Its Splicing Mechanism and Their Connection with Human Disease

2016 ◽  
Vol 15 (3) ◽  
pp. 307-312
Author(s):  
Mine Dosay-Akbulut
Keyword(s):  
Human Genome ◽  
Human Disease ◽  
Rna Splicing ◽  
Messenger Rna ◽  
Developmental Disorders ◽  
Regulation Of Gene Expression ◽  
Medical Science ◽  
Intronless Genes ◽  
Different Types ◽  
Extra Difficulty

In the maturation mechanism of a messenger RNA, splicing play an important role with removing the noncoding introns and ligating the coding exons. Alternative splicing (AS) gives an extra difficulty to this mechanism and to the regulation of gene expression. The possible disturbing in the alternative RNA splicing mechanism can be a reason to several diseases like cancers and neurodegenerative disorders. Intronless genes (IGs) are seen in almost 3% of the human genome. Functionality of IGs has an important role in signal transduction genes and related regulatory proteins. This diversity can be reason to IG-associated diseases, especially neuropathies, developmental disorders, and cancer. The retroelements can be seen in almost half of the human genome. The known informations indicate that insertion of retroelement into exons and introns of genes promote different types of genetic disease, including cancer. The retroelement connected mutagenesis cause to fifty different types of human disease. The molecular informations and bioinformatic analyses can be used to explain the connection with splicing mutations and genetic mechanisms of several different human disease and understanding of this mechanism play an important role in the formation of treatment programme against to these diseases.Bangladesh Journal of Medical Science Vol.15(3) 2016 p.307-312

Sign in / Sign up

Export Citation Format

Share Document