https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30416 Wed 11 Apr 2018 17:10:58 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26544 Wed 11 Apr 2018 15:40:57 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:28948 VDR) polymorphisms, BsmI and ApaI. Methods: Two hundred participants completed food frequency and supplement questionnaires, and were assayed for circulating let-7b expression by qPCR. Polymorphisms were detected using restriction fragment length polymorphism-PCR. Results: let-7b expression negatively correlated with vitamin D intake (r_s = -0.20, p = 0.005). The magnitude and direction of correlation were maintained in the presence of the BsmI restriction site (r_s = -0.27, p = 0.0005). However, in the absence of BsmI restriction site, the direction of the correlation was reversed (r_s = +0.319, p = 0.0497). These correlations were significantly different (z-score = 2.64, p = 0.0085). The correlation between vitamin D intake and let-7a was only significant in those without the ApaI restriction site. Conclusions: The correlation between vitamin D intake and let-7a/b expression in this cohort varies with VDR genotype. This study highlights the importance of considering underlying genotypic variance in miRNA expression studies and in nutritional epigenetics generally.]]> Wed 11 Apr 2018 14:17:40 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:23271 Wed 11 Apr 2018 10:32:06 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26534 Wed 06 Apr 2022 14:04:50 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30424 Thu 28 Oct 2021 12:36:47 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29660 CYP2R1, CYP27B1 and CYP24A1) and the Vitamin D receptor gene (VDR). This analysis was conducted in the context of dietary Vitamin D, and background methyl donor related biochemistry, with adjustment for several dietary and lifestyle variables. Percentage methylation at CpG sites was assessed in peripheral blood cells using methylation sensitive and dependent enzymes and qPCR. Standard analytical techniques were used to determine plasma 25(OH)D and homocysteine, and serum folate and B12, with the relationship to methylation status assessed using multi-variable regression analysis. CYP2R1 and VDR methylation were found to be independent predictors of plasma 25(OH)D, when adjusted for Vitamin D intake and other lifestyle variables. CYP24A1 was related to plasma 25(OH)D directly, but not in the context of Vitamin D intake. Methyl-group donor biochemistry was associated with the methylation status of some genes, but did not alter the relationship between methylation and plasma 25(OH)D. Modulation of methylation status of CYP2R1, CYP24A1 and VDR in response to plasma 25(OH)D may be part of feedback loops involved in maintaining Vitamin D homeostasis, and may explain a portion of the variance in plasma 25(OH)D levels in response to intake and sun exposure. Methyl-group donor biochemistry, while a potential independent modulator, did not alter this effect.]]> Mon 26 Apr 2021 10:02:52 AEST ]]>