The role of epigenetics in inflammatory memory

Inflammatory memory refers to the ability of an organism to mount a stronger or faster response upon re-exposure to similar inflammatory stimuli. This heightened sensitivity was once thought to be a unique characteristic of immune cells. However, recent studies have challenged this traditional view, revealing that inflammatory memory is a widely prevalent phenomenon that extends beyond immune cells to include nonimmune cells. These studies indicate that the formation and maintenance of inflammatory memory largely depend on the regulation of epigenetics. Epigenetics involves heritable changes in gene expression without altering the DNA sequence, including mechanisms such as DNA methylation and histone modifications. These modifications regulate gene transcription and influence the cellular response to inflammatory stimuli. In this review, we will discuss the epigenetic mechanisms of inflammatory memory in both immune and nonimmune cells, focusing on new mechanistic insights from the past few years, and briefly discuss the unknowns and future strategies.