Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.799854
Title: Role of sustained nutrient regimes in metabolism and epigenetics of diabetic and cancer cell models
Author: Singh, Akashdeep
ISNI:       0000 0004 8506 7190
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 2019
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Abstract:
Central metabolism plays an intrinsic role in the regulation of gene expression, as cells adapt their epigenetic profile in response to nutrient availability. Moreover, epidemiological studies revealed a strong correlation between various pathologies, such as metabolic syndromes and cancer with nutrient status. To address the molecular mechanisms of this link, a cancer model (HeLa) and β-cell model (INS-1) were exposed to a sustained acetate and galactose nutrient regimes. Under this treatment, assessment of gene expression and epigenetic profiles, both from IDH2 and insulin gene in INS-1 cells, and IDH2 and NIX in HeLa cells showed active regulation of DNA promoter methylation. Moreover, using a targeted dCAS9-Tet system, IDH2 epigenetic regulation was induced by promoter hydroxymethylation. In addition, acetate treatment led to the accumulation of DNMT3a protein in INS-1 cells, a process which was also enhanced by inhibiting proteasomal activity. Moreover, galactose led to reduction in the DNMT3a protein in HeLa cells. Functionally, acetate-treated INS-1 cells showed a significant reduction in mitDNA content, mtCOI expression, total α-ketoglutarate/ATP contents and increased histone acetylation levels, resulting in reduced insulin content. Whereas, galactose-treated HeLa cells showed a significant increase in mitDNA content, mtCOII expression, total α-ketoglutarate and reduction in histone acetylation, resulting in reduced proliferation and increased apoptosis. Overexpression of IDH2 effectively reverted the effects acetated-induced effect in INS-1 cells, as shown by DNMT3a protein abundance, histone acetylation and ATP content. Our results also show that the alterations in the nutrient availability of INS-1 cells, such as elevated acetate levels, led to a modified epigenetic control of IDH2 and insulin gene, subsequently altering cellular functions. Moreover, cell cycle analysis showed that IDH2 acetylation but not expression is regulated in cell cycle, and acetate (in the absence of glucose) can be sufficient in surpassing the nutrient sensitive restriction point during cell cycle. Collectively, these observations provide a mechanistic link between nutrient availability and epigenetic control in diabetes, cancer and cell cycle models, and highlight the rationale for interventions in this process as part of therapeutics strategies in cancer and diabetes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.799854  DOI: Not available
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