Research Progress on the Regulation of Macrophages by Histone Modification in Bronchial Asthma

Macrophages, a key component of the innate immune system, are closely associated with the occurrence and development of various lung diseases, such as chronic obstructive pulmonary disease (COPD), allergic asthma, acute lung injury, and idiopathic pulmonary fibrosis. Macrophages can differentiate into two types: the classical pro-inflammatory M1-like macrophages and the anti-inflammatory M2 macrophages. During the inflammatory process, these two types of macrophages are alternately activated. Therefore, it is extremely important to maintain the balance between the two types of macrophages. Epigenetics refers to the potentially heritable changes in gene expression without altering the DNA sequence. It is dynamic and reversible, including DNA methylation, histone modification, and non-coding RNA regulation. Among them, histone modification refers to the regulation of chemical modifications of histone tails, including methylation, acetylation, phosphorylation, ubiquitination, and lactic acidification, etc. An increasing amount of evidence indicates that the biological functions of macrophages are closely related to epigenetic modifications. Understanding the roles and mechanisms of macrophage-related epigenetic regulation can provide in-depth insights into the functions of macrophages in lung diseases. This article reviews the mechanisms of action of different histone modifications in macrophage polarization and their impacts on asthma, and describes the latest knowledge regarding the precise regulation of the biological functions of macrophages and their influence on asthma through epigenetic mechanisms.