Role of sustained nutrient regimes in metabolism and epigenetics of diabetic and cancer cell models

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Singh, A., 2019. Role of sustained nutrient regimes in metabolism and epigenetics of diabetic and cancer cell models. PhD, Nottingham Trent University.

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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.

Item Type:	Thesis
Creators:	Singh, A.
Date:	May 2019
Rights:	This work is the intellectual property of the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed to the owner of the Intellectual Property Rights.
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	29 Jan 2020 16:03
Last Modified:	29 Jan 2020 16:03
URI:	https://irep.ntu.ac.uk/id/eprint/39120