Environmental factors significantly impact gene expression through epigenetic modifications

Frontiers JournalsOct 8 2024

Epigenetics, the study of changes in gene function that do not involve alterations to the DNA sequence, plays a pivotal role in understanding the complex interplay between genetics and the environment. The review article "Epigenetics and Environmental Health" provides an in-depth analysis of how epigenetic modifications can influence the onset and progression of various diseases, particularly cancer and cardiovascular diseases. These modifications, which include DNA methylation, histone modifications, chromatin remodeling, and RNA modifications, are crucial for maintaining cell identity, proliferation, and differentiation, and are significantly influenced by environmental factors.

The concept of epigenetics was first introduced in 1942, and it has since evolved to become a key branch of biology that explains how genotypes and phenotypes are linked through a complex developmental process. All cells in the body contain the same DNA but can perform different functions, and it is epigenetic information that regulates this variability. Epigenetic modifications are essential for development and gene expression regulation. They can be activated in response to environmental signals without any changes to the DNA sequence, suggesting a mechanism for cellular adaptation to environmental changes.

The review emphasizes that changes in epigenetic patterns often stem from the profound effects of the environment on developmental plasticity. Historically, Hippocrates proposed that characteristics acquired in response to environmental exposure could be inherited. Modern research supports this idea, suggesting that epigenetic modifications can be activated in response to environmental signals, leading to heritable changes in cellular responses. These modifications can alter gene expression or function, either by directly affecting transcription factors or by influencing their response to environmental changes.

Cancer is a major focus of the review, with hepatocellular carcinoma (HCC) highlighted as a significant example. HCC accounts for 75%-85% of liver cancer cases, and while surgical resection may be effective in early stages, recurrence is common. The review discusses how epigenetic modifications such as DNA methylation, histone modifications, and RNA modifications are associated with cancer development. For instance, abnormal CpG island hypermethylation is frequently observed in cancers and is often linked to tumor suppressor genes. The review also points out the potential of epigenetic drugs in cancer treatment, with several drugs already approved by the US Food and Drug Administration (FDA) for clinical use.

Cardiovascular diseases are also linked to epigenetic changes. The review suggests that aging, which is associated with a decline in cardiovascular function, is influenced by epigenetic alterations. These modifications can affect the structure and function of the cardiovascular system, contributing to diseases such as hypertension, heart failure, atherosclerosis, and myocardial infarction. The role of histone modifications in atherosclerosis is particularly highlighted, with changes in histone acetylation and methylation found in atherosclerotic tissues.

Environmental exposure is a significant theme throughout the review. It discusses how factors such as air pollution, light pollution, smoking, alcohol, and sugar can induce epigenetic changes that affect gene expression and overall health. For example, short-term exposure to air pollution can affect mitochondrial DNA methylation, while long-term exposure can lead to hypomethylation of certain gene regions. The review also notes that environmental carcinogens, including air pollutants and heavy metals, can cause epigenetic changes that contribute to disease development.

The review concludes by emphasizing the need for further research to understand the mechanisms underlying the progression of diseases and the development of effective therapeutic methods. It suggests that understanding the link between environmental factors and epigenetics could lead to new strategies for disease prevention and treatment. The article also highlights the potential of epigenetic-based interventions, such as dietary modifications and pharmacological treatments, to counteract the effects of environmental exposures and improve public health.

In summary, the review provides a comprehensive overview of the current understanding of epigenetics in the context of environmental health. It underscores the importance of considering epigenetic factors in the development of diseases and the potential for targeted interventions to mitigate the impact of environmental factors on human health.