Disturbances in PP2A methylation and one-carbon metabolism compromise Fyn distribution, neuritogenesis and APP regulation

The nonreceptor protein tyrosine kinase Fyn and protein Ser/Thr phosphatase 2A (PP2A) are major multifunctional signaling molecules. Deregulation of Fyn and altered PP2A methylation are implicated in cancer and Alzheimer disease (AD). Here, we tested the hypothesis that the methylation state of PP2A catalytic subunit, which influences PP2A subunit composition and substrate specificity, can affect Fyn regulation and function. Using N2a neuroblastoma cell models, we first show that methylated PP2A holoenzymes containing the Bα subunit co-immunoprecipitate and co-purify with Fyn in membrane rafts. PP2A methylation status regulates Fyn distribution and Fyn-dependent neuritogenesis, likely in part by affecting actin dynamics. A methylation incompetent PP2A mutant fails to interact with Fyn. It perturbs the normal partitioning of Fyn and amyloid precursor protein (APP) in membrane microdomains, which governs Fyn function and APP processing. This correlates with enhanced amyloidogenic cleavage of APP, a hallmark of AD pathogenesis. Conversely, enhanced PP2A methylation promotes the nonamyloidogenic cleavage of APP in a Fyn-dependent manner. Disturbances in one-carbon metabolic pathways that control cellular methylation are associated with AD and cancer. Notably, they induce a parallel loss of membrane-associated methylated PP2A and Fyn enzymes in N2a cells and acute mouse brain slices. One-carbon metabolism also modulates Fyn-dependent process outgrowth in N2a cells. Thus, our findings identify a novel methylation dependent PP2A/Fyn signaling module. They highlight the underestimated importance of crosstalks between essential metabolic pathways and signaling scaffolds that are involved in normal cell homeostasis and currently being targeted for cancer and AD treatment.

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Polyamine Metabolism and Gene Methylation in Conjunction with One-Carbon Metabolism

International Journal of Molecular Sciences ◽

10.3390/ijms19103106 ◽

2018 ◽

Vol 19 (10) ◽

pp. 3106 ◽

Cited By ~ 19

Author(s):

Kuniyasu Soda

Keyword(s):

Dna Methylation ◽

Carbon Metabolism ◽

Methylation Status ◽

Significant Risk ◽

Significant Risk Factor ◽

Dna Methyltransferases ◽

Polyamine Metabolism ◽

Methyl Group ◽

Wide Range ◽

One Carbon Metabolism

Recent investigations have revealed that changes in DNA methylation status play an important role in aging-associated pathologies and lifespan. The methylation of DNA is regulated by DNA methyltransferases (DNMT1, DNMT3a, and DNMT3b) in the presence of S-adenosylmethionine (SAM), which serves as a methyl group donor. Increased availability of SAM enhances DNMT activity, while its metabolites, S-adenosyl-l-homocysteine (SAH) and decarboxylated S-adenosylmethionine (dcSAM), act to inhibit DNMT activity. SAH, which is converted from SAM by adding a methyl group to cytosine residues in DNA, is an intermediate precursor of homocysteine. dcSAM, converted from SAM by the enzymatic activity of adenosylmethionine decarboxylase, provides an aminopropyl group to synthesize the polyamines spermine and spermidine. Increased homocysteine levels are a significant risk factor for the development of a wide range of conditions, including cardiovascular diseases. However, successful homocysteine-lowering treatment by vitamins (B6, B12, and folate) failed to improve these conditions. Long-term increased polyamine intake elevated blood spermine levels and inhibited aging-associated pathologies in mice and humans. Spermine reversed changes (increased dcSAM, decreased DNMT activity, aberrant DNA methylation, and proinflammatory status) induced by the inhibition of ornithine decarboxylase. The relation between polyamine metabolism, one-carbon metabolism, DNA methylation, and the biological mechanism of spermine-induced lifespan extension is discussed.

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Association between one-carbon metabolism indices and DNA methylation status in maternal and cord blood

Scientific Reports ◽

10.1038/s41598-018-35111-1 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 5

Author(s):

Anna K. Knight ◽

Hea Jin Park ◽

Dorothy B. Hausman ◽

Jennifer M. Fleming ◽

Victoria L. Bland ◽

...

Keyword(s):

Dna Methylation ◽

Cord Blood ◽

Carbon Metabolism ◽

Methylation Status ◽

One Carbon Metabolism

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Green Tea Seed Isolated Theasaponin E1 Ameliorates AD Promoting Neurotoxic Pathogenesis by Attenuating Aβ Peptide Levels in SweAPP N2a Cells

Molecules ◽

10.3390/molecules25102334 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2334 ◽

Cited By ~ 1

Author(s):

Muhammad Imran Khan ◽

Jin Hyuk Shin ◽

Min Yong Kim ◽

Tai Sun Shin ◽

Jong Deog Kim

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Green Tea ◽

Neuroblastoma Cells ◽

Dependent Manner ◽

Insulin Degrading Enzyme ◽

App Processing ◽

N2a Cells ◽

Gene And Protein Expression ◽

Dose Dependent

Alzheimer’s disease (AD) is the most frequent type of dementia affecting memory, thinking and behaviour. The major hallmark of the disease is pathological neurodegeneration due to abnormal aggregation of Amyloid beta (Aβ) peptides generated by β- and γ-secretases via amyloidogenic pathway. Purpose of the current study was to evaluate the effects of theasaponin E1 on the inhibition of Aβ producing β-, γ-secretases (BACE1, PS1 and NCT) and acetylcholinesterase and activation of the non-amyloidogenic APP processing α-secretase (ADAM10). Additionally, theasaponin E1 effects on Aβ degrading and clearing proteins neprilysin and insulin degrading enzyme (IDE). The effect of theasaponin E1 on these crucial enzymes was investigated by RT-PCR, ELISA, western blotting and fluorometric assays using mouse neuroblastoma cells (SweAPP N2a). theasaponin E1 was extracted and purified from green tea seed extract via HPLC, and N2a cells were treated with different concentrations for 24 h. Gene and protein expression in the cells were measured to determine the effects of activation and/or inhibition of theasaponin E1 on β- and γ-secretases, neprilysin and IDE. Results demonstrated that theasaponin E1 significantly reduced Aβ concentration by activation of the α-secretase and neprilysin. The activities of β- and γ-secretase were reduced in a dose-dependent manner due to downregulation of BACE1, presenilin, and nicastrin. Similarly, theasaponin E1 significantly reduced the activity of acetylcholinesterase. Overall, from the results it is concluded that green tea seed extracted saponin E1 possess therapeutic significance as a neuroprotective natural product recommended for the treatment of Alzheimer’s disease.

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FMO rewires metabolism to promote longevity through tryptophan and one carbon metabolism

10.1101/2021.06.18.449022 ◽

2021 ◽

Author(s):

Hyo Sub Choi ◽

Ajay Bhat ◽

Marshall B. Howington ◽

Megan L. Schaller ◽

Rebecca Cox ◽

...

Keyword(s):

Carbon Metabolism ◽

Metabolic Pathways ◽

Critical Role ◽

Unknown Mechanism ◽

C Elegans ◽

Metabolic Remodeling ◽

Wide Range ◽

Exogenous Compounds ◽

One Carbon Metabolism ◽

Single Enzyme

Flavin containing monooxygenases (FMOs) are promiscuous enzymes known for metabolizing a wide range of exogenous compounds. In C. elegans, fmo-2 expression increases lifespan and healthspan downstream of multiple longevity-promoting pathways through an unknown mechanism. Here, we report that, contrary to its classification as a xenobiotic enzyme, fmo-2 expression leads to rewiring of endogenous metabolism principally through changes in one carbon metabolism (OCM). Using computer modeling, we identify decreased methylation as the major OCM flux modified by FMO-2 that is sufficient to recapitulate its longevity benefits. We further find that tryptophan is decreased in multiple mammalian FMO overexpression models and is a validated substrate for FMO enzymes. Our resulting model connects a single enzyme to two previously unconnected key metabolic pathways and provides a framework for the metabolic interconnectivity of longevity-promoting pathways such as dietary restriction. FMOs are well-conserved enzymes that are also induced by lifespan-extending interventions in mice, supporting a conserved and critical role in promoting health and longevity through metabolic remodeling.

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Integrative modeling of tumor DNA methylation identifies a role for metabolism

10.1101/057638 ◽

2016 ◽

Author(s):

Mahya Mehrmohamadi ◽

Lucas K. Mentch ◽

Andrew G. Clark ◽

Jason W. Locasale

Keyword(s):

Dna Methylation ◽

Carbon Metabolism ◽

Methylation Status ◽

Individual Variability ◽

Early Event ◽

Large Contribution ◽

Cancer Type ◽

Relative Contribution ◽

One Carbon Metabolism ◽

Genomic Regions

AbstractDNA methylation varies across genomic regions, tissues and individuals in a population. Altered DNA methylation is common in cancer and often considered an early event in tumorigenesis. However, the sources of heterogeneity of DNA methylation among tumors remain poorly defined. Here, we capitalize on the availability of multi-platform data on thousands of molecularly-and clinically-annotated human tumors to build integrative models that identify the determinants of DNA methylation. We quantify the relative contribution of clinical and molecular factors in explaining within-cancer (inter-individual) variability in DNA methylation. We show that the levels of a set of metabolic genes involved in the methionine cycle that are constituents of one-carbon metabolism are predictive of several features of DNA methylation status in tumors including the methylation of genes that are known to drive oncogenesis. Finally, we demonstrate that patients whose DNA methylation status can be predicted from the genes in one-carbon metabolism exhibited improved survival over cases where this regulation is disrupted. To our knowledge, this study is the first comprehensive analysis of the determinants of methylation and demonstrates the surprisingly large contribution of metabolism in explaining epigenetic variation among individual tumors of the same cancer type. Together, our results illustrate links between tumor metabolism and epigenetics and outline future clinical implications.

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Dietary methionine restriction targets one carbon metabolism in humans and produces broad therapeutic responses in cancer

10.1101/627364 ◽

2019 ◽

Cited By ~ 3

Author(s):

Xia Gao ◽

Sydney M. Sanderson ◽

Ziwei Dai ◽

Michael A. Reid ◽

Daniel E. Cooper ◽

...

Keyword(s):

Tumor Cell ◽

Carbon Metabolism ◽

Metabolic Pathways ◽

Colorectal Cancer Patient ◽

Soft Tissue Sarcomas ◽

Nucleotide Metabolism ◽

Dietary Interventions ◽

One Carbon Metabolism ◽

Cancer Outcome ◽

Therapeutic Responses

AbstractNutrition exerts profound effects on health and dietary interventions are commonly used to treat diseases of metabolic etiology. Although cancer has a substantial metabolic component, the principles that define whether nutrition may be used to influence tumour outcome are unclear. Nevertheless, it is established that targeting metabolic pathways with pharmacological agents or radiation can sometimes lead to controlled therapeutic outcomes. In contrast, whether specific dietary interventions could influence the metabolic pathways that are targeted in standard cancer therapies is not known. We now show that dietary restriction of methionine (MR), an essential amino acid, and the reduction of which has aging and obesogenic properties, influences cancer outcome through controlled and reproducible changes to one carbon metabolism. This pathway metabolizes methionine and further is the target of a host of cancer interventions involving chemotherapy and radiation. MR produced therapeutic responses in chemoresistant RAS-driven colorectal cancer patient derived xenografts and autochthonous KRASG12D+/−;TP53−/− -driven soft tissue sarcomas resistant to radiation. Metabolomics revealed the therapeutic mechanisms to occur through tumor cell autonomous effects on the flux through one carbon metabolism that impacted redox and nucleotide metabolism, thus interacting with the antimetabolite or radiation intervention. Finally, in a controlled and tolerated feeding study in humans, MR resulted in similar effects on systemic metabolism as obtained in responsive mice. These findings provide evidence that a targeted dietary manipulation can affect specific tumor cell metabolism to mediate broad aspects of cancer outcome.

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Genetic Variation: Impact on Folate (and Choline) Bioefficacy

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000040 ◽

2010 ◽

Vol 80 (45) ◽

pp. 319-329 ◽

Cited By ~ 9

Author(s):

Allyson A. West ◽

Marie A. Caudill

Keyword(s):

Carbon Metabolism ◽

Genetic Variants ◽

Plasma Homocysteine ◽

Water Soluble ◽

Gene Interactions ◽

Dietary Folate ◽

Methyl Donors ◽

Common Genetic Variants ◽

One Carbon Metabolism ◽

The Impact

Folate and choline are water-soluble micronutrients that serve as methyl donors in the conversion of homocysteine to methionine. Inadequacy of these nutrients can disturb one-carbon metabolism as evidenced by alterations in circulating folate and/or plasma homocysteine. Among common genetic variants that reside in genes regulating folate absorptive and metabolic processes, homozygosity for the MTHFR 677C > T variant has consistently been shown to have robust effects on status markers. This paper will review the impact of genetic variants in folate-metabolizing genes on folate and choline bioefficacy. Nutrient-gene and gene-gene interactions will be considered along with the need to account for these genetic variants when updating dietary folate and choline recommendations.

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Review for "Prognostic impact of B‐vitamins involved in one‐carbon metabolism in patients with diffuse large B‐cell lymphoma"

10.1002/hon.2752/v3/review1 ◽

2020 ◽

Keyword(s):

B Cell ◽

Carbon Metabolism ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

B Vitamins ◽

Prognostic Impact ◽

Large B Cell Lymphoma ◽

One Carbon Metabolism ◽

Large B Cell

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Grape Seed Proanthocyanidins Protect N2a Cells against Ischemic Injury via Endoplasmic Reticulum Stress and Mitochondrial-associated Pathways

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527318666190212111650 ◽

2019 ◽

Vol 18 (4) ◽

pp. 334-341 ◽

Cited By ~ 3

Author(s):

Kun Fu ◽

Liqiang Chen ◽

Lifeng Miao ◽

Yan Guo ◽

Wei Zhang ◽

...

Keyword(s):

Membrane Potential ◽

Cell Viability ◽

Mitochondrial Membrane Potential ◽

Mitochondrial Membrane ◽

Grape Seed ◽

Mrna Levels ◽

Dependent Manner ◽

Grape Seed Proanthocyanidins ◽

N2a Cells ◽

Caspase 12

Background/Objective: Grape seed proanthocyanidins (GSPs) are a group of polyphenolic bioflavonoids, which possess a variety of biological functions and pharmacological properties. We studied the neuroprotective effects of GSP against oxygen-glucose deprivation/reoxygenation (OGD/R) injury and the potential mechanisms in mouse neuroblastoma N2a cells. Methods: OGD/R was conducted in N2a cells. Cell viability was evaluated by CCK-8 and LDH release assay. Apoptosis was assessed by TUNEL staining and flow cytometry. Protein levels of cleaved caspase-3, Bax and Bcl-2 were detected by Western blotting. CHOP, GRP78 and caspase-12 mRNA levels were assessed by real-time PCR. JC-1 dying was used to detect mitochondrial membrane potential. ROS levels, activities of endogenous antioxidant enzymes and ATP production were examined to evaluate mitochondrial function. Results: GSP increased cell viability after OGD/R injury in a dose-dependent manner. Furthermore, GSP inhibited cell apoptosis, reduced the mRNA levels of CHOP, GRP78 and caspase-12 (ER stressassociated genes), restored mitochondrial membrane potential and ATP generation, improved activities of endogenous anti-oxidant ability (T-AOC, GXH-Px, and SOD), and decreased ROS level. Conclusion: Our findings suggest that GSP can protect N2a cells from OGD/R insult. The mechanism of anti-apoptotic effects of GSP may involve attenuating ER stress and mitochondrial dysfunction.

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