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Nathan Goodyear

An integrative analysis reveals coordinated reprogramming of the epigenome and the tran... - 0 views

  • contribution to the training response of the epigenome as a mediator between genes and environment
  • Differential DNA methylation was predominantly observed in enhancers, gene bodies and intergenic regions and less in CpG islands or promoters
  • highly consistent and associated modifications in methylation and expression, concordant with observed health-enhancing phenotypic adaptations, are induced by a physiological stimulus
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  • The health benefits following exercise training are elicited by gene expression changes in skeletal muscle, which are fundamental to the remodeling process
  • there is increasing evidence that more short-term environmental factors can influence DNA methylation
  • dietary factors have the potency to alter the degree of DNA methylation in different tissues, 9,10 including skeletal muscle
  • In one study, a single bout of endurance-type exercise was shown to affect methylation at a few promoter CpG sites
  • In the context of diabetes, exercise training has been shown to affect genome-wide methylation pattern in skeletal muscle,13 as well as in adipose tissue.
  • physiological stressors can indeed affect DNA methylation
  • training intervention reshapes the epigenome and induces significant changes in DNA methylation
  • the findings from this tightly controlled human study strongly suggest that the regulation and maintenance of exercise training adaptation is to a large degree associated to epigenetic changes, especially in regulatory enhancer regions
  • Endurance training [after training (T2) vs. before training (T1)] induced significant (false discovery rate, FDR< 0.05) methylation changes at 4919 sites across the genome in the trained leg
  • identified 4076 differentially expressed genes
  • a complementary approach revealed that over 600 CpG sites correlated to the increase in citrate synthase activity, an objective measure of training response (Figure S4 and Dataset S14). This might imply that some of these sites could influence the degree of training response.
  • As expected by a physiological environmental trigger on adult tissue, the observed effect size on DNA methylation was small in comparison to disease states such as cancer
  • a preferential localization outside of CpG Islands/Shelves/Shores
  • endurance training especially influences enhancers
  • negative correlation was more prominent for probes in promoter/5′UTR/1st exon regions, while gene bodies had a stronger peak of positive correlation
  • The significant changes in DNA methylation, that primarily occurred in enhancer regions, were to a large extent associated with relevant changes in gene expression
  • The main findings of this study were that 3 months of endurance training in healthy human volunteers induced significant methylation changes at almost 5000 sites across the genome and significant differential expression of approximately 4000 genes
  • DMPs that increased in methylation were mainly associated to structural remodeling of the muscle and glucose metabolism, while the DMPs with decreased methylation were associated to inflammatory/immunological processes and transcriptional regulation
  • This suggests that the changes in methylation seen with training were not a random effect across the genome but rather a controlled process that likely contributes to skeletal muscle adaptation to endurance training
  • Correlation of the changes in DNA methylation to the changes in gene expression showed that the majority of significant methylation/expression pairs were found in the groups representing either increases in expression with a concomitant decrease in methylation or vice versa
  • The fraction of genes showing both significant decrease in methylation and upregulation was 7.5% of the DEGs or 2.3% of all genes detected in muscle tissue with at least one measured DNA methylation position. Correspondingly, 7.0% of the DEGs or 2.1% of all genes showed both significant increase in methylation and downregulation
  • we show that DNA methylation changes are associated to gene expression changes in roughly 20% of unique genes that significantly changed with training
  • Examples of structural genes include COL4A1, COL4A2 and LAMA4. These genes have also been identified as important for differences in responsiveness to endurance training
  • methylation status could be part of the mechanism behind variable training response
  • Among the metabolic genes, MDH1 catalyzes the reversible oxidation of malate to oxaloacetate, utilizing the NAD/NADH cofactor system in the citric acid cycle and NDUFA8 plays an important role in transferring electrons from NADH to the respiratory chain
  • PPP1R12A,
  • In the present study, methylation predominantly changed in enhancer regions with enrichment for binding motifs for different transcription factors suggesting that enhancer methylation may be highly relevant also in exercise biology
  • Of special interest in the biology of endurance training may be that MRFs, through binding to the PGC-1α core promoter, can regulate this well-studied co-factor for mitochondrial biogenesis
  • That endurance training led to an increased methylation in enhancer regions containing motifs for the MRFs and MEFs is somewhat counterintuitive since it should lead to the repression of the action of the above discussed transcription factors
  • decrease with training in this study, including CDCH15, MYH3, TNNT2, RYR1 and SH3GLB1
  • expression of MEF2A itself decreased with training
  • this study demonstrates that the transcriptional alterations in skeletal muscle in response to a long-term endurance exercise intervention are coupled to DNA methylation changes
  • We suggest that the training-induced coordinated epigenetic reprogramming mainly targets enhancer regions, thus contributing to differences in individual response to lifestyle interventions
  • a physiological health-enhancing stimulus can induce highly consistent modifications in DNA methylation that are associated to gene expression changes concordant with observed phenotypic adaptations
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    Exercise alters gene expression via methylation--the power of epigenetics.  Interestingly, the majority of the methylation was outside the CPG island regions.  This 3 month study found methylation of 5,000 sites across the genome resulting in altered expression of apps 4,000 genes.  The altered muscle changes of the endurance training was linked to DNA methylation changes.
Nathan Goodyear

Reversal of Maternal Programming of Stress Responses in Adult Offspring through Methyl ... - 0 views

  • These results demonstrate that, despite the inherent stability of the epigenomic marks established early in life through behavioral programming, they are potentially reversible in the adult brain.
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    We are products of our genetics and our environment
Nathan Goodyear

Press-pulse: a novel therapeutic strategy for the metabolic management of cancer | Nutr... - 0 views

  • A “press” disturbance was considered a chronic environmental stress on all organisms in an ecological community
  • “pulse” disturbances were considered acute events that disrupted biological communities to produce high mortality
  • Neoplasia involving dysregulated cell growth is the biological endpoint of the disease
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  • Data from the American Cancer Society show that the rate of increase in cancer deaths/year (3.4%) was two-fold greater than the rate of increase in new cases/year (1.7%) from 2013 to 2017
  • cancer is predicted to overtake heart disease as the leading cause of death in Western societies
  • cancer can also be recognized as a metabolic disease.
  • glucose is first split into two molecules of pyruvate through the Embden–Meyerhof–Parnas glycolytic pathway in the cytosol
  • Aerobic fermentation, on the other hand, involves the production of lactic acid under normoxic conditions
  • persistent lactic acid production in the presence of adequate oxygen is indicative of abnormal respiration
  • Otto Warburg first proposed that all cancers arise from damage to cellular respiration
  • The Crabtree effect is an artifact of the in vitro environment and involves the glucose-induced suppression of respiration with a corresponding elevation of lactic acid production even under hyperoxic (pO2 = 120–160 mmHg) conditions associated with cell culture
  • the Warburg theory of insufficient aerobic respiration remains as the most credible explanation for the origin of tumor cells [2, 37, 51, 52, 53, 54, 55, 56, 57].
  • The main points of Warburg’s theory are; 1) insufficient respiration is the predisposing initiator of tumorigenesis and ultimately cancer, 2) energy through glycolysis gradually compensates for insufficient energy through respiration, 3) cancer cells continue to produce lactic acid in the presence of oxygen, and 4) respiratory insufficiency eventually becomes irreversible
  • Efraim Racker coined the term “Warburg effect”, which refers to the aerobic glycolysis that occurs in cancer cells
  • Warburg clearly demonstrated that aerobic fermentation (aerobic glycolysis) is an effect, and not the cause, of insufficient respiration
  • all tumor cells that have been examined to date contain abnormalities in the content or composition of cardiolipin
  • The evidence supporting Warburg’s original theory comes from a broad range of cancers and is now overwhelming
  • respiratory insufficiency, arising from any number mitochondrial defects, can contribute to the fermentation metabolism seen in tumor cells.
  • data from the nuclear and mitochondrial transfer experiments suggest that oncogene changes are effects, rather than causes, of tumorigenesis
  • Normal mitochondria can suppress tumorigenesis, whereas abnormal mitochondria can enhance tumorigenesis
  • In addition to glucose, cancer cells also rely heavily on glutamine for growth and survival
  • Glutamine is anapleurotic and can be rapidly metabolized to glutamate and then to α-ketoglutarate for entry into the TCA cycle
  • Glucose and glutamine act synergistically for driving rapid tumor cell growth
  • Glutamine metabolism can produce ATP from the TCA cycle under aerobic conditions
  • Amino acid fermentation can generate energy through TCA cycle substrate level phosphorylation under hypoxic conditions
  • Hif-1α stabilization enhances aerobic fermentation
  • targeting glucose and glutamine will deprive the microenvironment of fermentable fuels
  • Although Warburg’s hypothesis on the origin of cancer has created confusion and controversy [37, 38, 39, 40], his hypothesis has never been disproved
  • Warburg referred to the phenomenon of enhanced glycolysis in cancer cells as “aerobic fermentation” to highlight the abnormal production of lactic acid in the presence of oxygen
  • Emerging evidence indicates that macrophages, or their fusion hybridization with neoplastic stem cells, are the origin of metastatic cancer cells
  • Radiation therapy can enhance fusion hybridization that could increase risk for invasive and metastatic tumor cells
  • Kamphorst et al. in showing that pancreatic ductal adenocarcinoma cells could obtain glutamine under nutrient poor conditions through lysosomal digestion of extracellular proteins
  • It will therefore become necessary to also target lysosomal digestion, under reduced glucose and glutamine conditions, to effectively manage those invasive and metastatic cancers that express cannibalism and phagocytosis.
  • Previous studies in yeast and mammalian cells show that disruption of aerobic respiration can cause mutations (loss of heterozygosity, chromosome instability, and epigenetic modifications etc.) in the nuclear genome
  • The somatic mutations and genomic instability seen in tumor cells thus arise from a protracted reliance on fermentation energy metabolism and a disruption of redox balance through excess oxidative stress.
  • According to the mitochondrial metabolic theory of cancer, the large genomic heterogeneity seen in tumor cells arises as a consequence, rather than as a cause, of mitochondrial dysfunction
  • A therapeutic strategy targeting the metabolic abnormality common to most tumor cells should therefore be more effective in managing cancer than would a strategy targeting genetic mutations that vary widely between tumors of the same histological grade and even within the same tumor
  • Tumor cells are more fit than normal cells to survive in the hypoxic niche of the tumor microenvironment
  • Hypoxic adaptation of tumor cells allows for them to avoid apoptosis due to their metabolic reprograming following a gradual loss of respiratory function
  • The high rates of tumor cell glycolysis and glutaminolysis will also make them resistant to apoptosis, ROS, and chemotherapy drugs
  • Despite having high levels of ROS, glutamate-derived from glutamine contributes to glutathione production that can protect tumor cells from ROS
    • Nathan Goodyear
       
      reason to eliminate glutamine in cancer patients and even GSH with cancer patients
  • It is clear that adaptability to environmental stress is greater in normal cells than in tumor cells, as normal cells can transition from the metabolism of glucose to the metabolism of ketone bodies when glucose becomes limiting
  • Mitochondrial respiratory chain defects will prevent tumor cells from using ketone bodies for energy
  • glycolysis-dependent tumor cells are less adaptable to metabolic stress than are the normal cells. This vulnerability can be exploited for targeting tumor cell energy metabolism
  • In contrast to dietary energy reduction, radiation and toxic drugs can damage the microenvironment and transform normal cells into tumor cells while also creating tumor cells that become highly resistant to drugs and radiation
  • Drug-resistant tumor cells arise in large part from the damage to respiration in bystander pre-cancerous cells
  • Because energy generated through substrate level phosphorylation is greater in tumor cells than in normal cells, tumor cells are more dependent than normal cells on the availability of fermentable fuels (glucose and glutamine)
  • Ketone bodies and fats are non-fermentable fuels
  • Although some tumor cells might appear to oxidize ketone bodies by the presence of ketolytic enzymes [181], it is not clear if ketone bodies and fats can provide sufficient energy for cell viability in the absence of glucose and glutamine
  • Apoptosis under energy stress is greater in tumor cells than in normal cells
  • A calorie restricted ketogenic diet or dietary energy reduction creates chronic metabolic stress in the body
  • . This energy stress acts as a press disturbance
  • Drugs that target availability of glucose and glutamine would act as pulse disturbances
  • Hyperbaric oxygen therapy can also be considered another pulse disturbance
  • The KD can more effectively reduce glucose and elevate blood ketone bodies than can CR alone making the KD potentially more therapeutic against tumors than CR
  • Campbell showed that tumor growth in rats is greater under high protein (>20%) than under low protein content (<10%) in the diet
  • Protein amino acids can be metabolized to glucose through the Cori cycle
  • The fats in KDs used clinically also contain more medium chain triglycerides
  • Calorie restriction, fasting, and restricted KDs are anti-angiogenic, anti-inflammatory, and pro-apoptotic and thus can target and eliminate tumor cells through multiple mechanisms
  • Ketogenic diets can also spare muscle protein, enhance immunity, and delay cancer cachexia, which is a major problem in managing metastatic cancer
  • GKI values of 1.0 or below are considered therapeutic
  • The GKI can therefore serve as a biomarker to assess the therapeutic efficacy of various diets in a broad range of cancers.
  • It is important to remember that insulin drives glycolysis through stimulation of the pyruvate dehydrogenase complex
  • The water-soluble ketone bodies (D-β-hydroxybutyrate and acetoacetate) are produced largely in the liver from adipocyte-derived fatty acids and ketogenic dietary fat. Ketone bodies bypass glycolysis and directly enter the mitochondria for metabolism to acetyl-CoA
  • Due to mitochondrial defects, tumor cells cannot exploit the therapeutic benefits of burning ketone bodies as normal cells would
  • Therapeutic ketosis with racemic ketone esters can also make it feasible to safely sustain hypoglycemia for inducing metabolic stress on cancer cells
    • Nathan Goodyear
       
      Ketones are much more than energy adaptabilit, but actually are therapeutic.
  • ketone bodies can inhibit histone deacetylases (HDAC) [229]. HDAC inhibitors play a role in targeting the cancer epigenome
  • Therapeutic ketosis reduces circulating inflammatory markers, and ketones directly inhibit the NLRP3 inflammasome, an important pro-inflammatory pathway linked to carcinogenesis and an important target for cancer treatment response
  • Chronic psychological stress is known to promote tumorigenesis through elevations of blood glucose, glucocorticoids, catecholamines, and insulin-like growth factor (IGF-1)
  • In addition to calorie-restricted ketogenic diets, psychological stress management involving exercise, yoga, music etc. also act as press disturbances that can help reduce fatigue, depression, and anxiety in cancer patients and in animal models
  • Ketone supplementation has also been shown to reduce anxiety behavior in animal models
  • This physiological state also enhances the efficacy of chemotherapy and radiation therapy, while reducing the side effects
  • lower dosages of chemotherapeutic drugs can be used when administered together with calorie restriction or restricted ketogenic diets (KD-R)
  • Besides 2-DG, a range of other glycolysis inhibitors might also produce similar therapeutic effects when combined with the KD-R including 3-bromopyruvate, oxaloacetate, and lonidamine
    • Nathan Goodyear
       
      oxaloacetate is a glycolytic inhibitor, as is doxycycline, and IVC.
  • A synergistic interaction of the KD diet plus radiation was seen
  • It is important to recognize, however, that the radiotherapy used in glioma patients can damage the respiration of normal cells and increase availability of glutamine in the microenvironment, which can increase risk of tumor recurrence especially when used together with the steroid drug dexamethasone
  • Poff and colleagues demonstrated that hyperbaric oxygen therapy (HBOT) enhanced the ability of the KD to reduce tumor growth and metastasis
  • HBOT also increases oxidative stress and membrane lipid peroxidation of GBM cells in vitro
  • The effects of the KD and HBOT can be enhanced with administration of exogenous ketones, which further suppressed tumor growth and metastasis
  • Besides HBOT, intravenous vitamin C and dichloroacetate (DCA) can also be used with the KD to selectively increase oxidative stress in tumor cells
  • Recent evidence also shows that ketone supplementation may enhance or preserve overall physical and mental health
  • Some tumors use glucose as a prime fuel for growth, whereas other tumors use glutamine as a prime fuel [102, 186, 262, 263, 264]. Glutamine-dependent tumors are generally less detectable than glucose-dependent under FDG-PET imaging, but could be detected under glutamine-based PET imaging
  • GBM and use glutamine as a major fuel
  • Many of the current treatments used for cancer management are based on the view that cancer is a genetic disease
  • Emerging evidence indicates that cancer is a mitochondrial metabolic disease that depends on availability of fermentable fuels for tumor cell growth and survival
  • Glucose and glutamine are the most abundant fermentable fuels present in the circulation and in the tumor microenvironment
  • Low-carbohydrate, high fat-ketogenic diets coupled with glycolysis inhibitors will reduce metabolic flux through the glycolytic and pentose phosphate pathways needed for synthesis of ATP, lipids, glutathione, and nucleotides
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    Cancer is a mitochondrial disease? So says the well published Dr Seyfried. Glucose and glutamine drive cancer growth.
Nathan Goodyear

Vitamin C - a new player in regulation of the cancer epigenome - 0 views

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    Vitamin C has more than just cytotoxicity effects against cancer, it has Epigenetics demethylation effects that inhibit cancer proliferation.
Nathan Goodyear

Reprogramming the Epigenome With Vitamin C - 1 views

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    Awesome read!! Vitamin C has immense Epigenetic properties.
Nathan Goodyear

Postnatal diet remodels hepatic DNA methylation in metabolic pathways established by a ... - 0 views

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    Only abstract available here.  Maternal nutrition, high fat diet in this study, altered genetic expression of offspring to increase future disease risk.  This study would have been better served if they had differentiated fats i.e. PUFA, MUFA, SF, TF....
Nathan Goodyear

Vitamin C - A new player in regulation of the cancer epigenome. - PubMed - 0 views

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    Only abstract available here. I will post the full article when I find it. Vitamin C, in addition to its anti-cancer properties, found to change epigenetic expression.
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