The effects of environmental stressors on candidate aging associated genes

Aging is defined as a biological and physical complex process that is characterized by the increase in susceptibility to diseases and eventually death. Aging may occur at different rates between and within species, especially or (it varies) among the long-lived ones. Here, we ask whether this diversity (e.g. aging phenotype) stems from genetic or environmental factors or as a combination between the two (epigenetics). Epigenetics play a central role in controlling changes in gene expression during aging. DNA methylation is the most abundant epigenetic modification among vertebrates and is essential to mammalian development.

In this study, we utilized the HELPtag assay to identify five candidate genes that were significantly hyper- or hypo-methylated across four different age groups in mice. The candidate genes were annotated using ensemble and their expression was further tested in vitro using the murine RAW 264.7 cell line to examine the effect of three environmental stressors (UV radiation, Hypoxia and fasting) on their expression. RNA was extracted at different time points followed by cDNA synthesis. Changes in gene expression were evaluated using qRT-PCR.

We show that fasting and UV radiation reduced the viability of RAW264.7 cells. We also found a significant change in three candidate genes' expression levels during fasting (TOP2B, RNF13 and MRPL4). Furthermore, we found a significant change in the four candidate genes' expression levels following UVC treatment (TOP2B, RNF13, PKNOX1 and CREB5) and yet no changes were recorded in hypoxic conditions.

Our results suggest that the model we used was a fitting model for the assessment of environmental stressors on candidate gene expression. In addition, we established a cellular response to the environment via changes in gene expression.