Microecology research: a new target for the prevention of asthma

Abstract

The incidence and prevalence of asthma have increased remarkably in recent years. There are lots of factors contributing to the occurrence and development of asthma. With the improvement of sequencing technology, it has been found that the microbiome plays an important role in the formation of asthma in early life. The roles of the microbial environment and human microbiome in the occurrence and development of asthma have attracted more and more attention. The environmental microbiome influences the occurrence of asthma by shaping the human microbiome. The specific mechanism may be related to the immune regulation of Toll-like receptors and T cells (special Tregs). Intestinal microbiome is formed and changed by regulating diet and lifestyle in early life, which may affect the development and maturation of the pulmonary immune system through the intestinal-pulmonary axis. It is well-recognized that both environmental microbiomes and human microbiomes can influence the onset of asthma. This review aims to summarize the recent advances in the research of microbiome, its relationship with asthma, and the possible mechanism of the microbiome in the occurrence and development of asthma. The research of the microbial environment and human microbiome may provide a new target for the prevention of asthma in children who have high-risk factors to allergy. However, further study of "when and how" to regulate microbiome is still needed.

Figure 1

T helper cells (Th) can differentiate into two subtypes (Th1 and Th2), and there is a dynamic balance between Th1 and Th2. When the immune response of Th1 is strong, the activity and function of Th2 will be greatly inhibited and reduced, and vice versa. (A) When the organism is exposed to a rural environment and high endotoxin, the secretion function of Th1 increases and the chance of allergic diseases will be greatly reduced. (B) When the body is exposed to PM2.5, tobacco, or non-pathogenic (SPF) environment, the secretion mediated by Th2 increases and further leads to asthma. PM2.5: Particulate matter <2.5 μm; SPF: Specific pathogen-free; Th1: T helper cell-1; Th2: T helper cell-2.

Figure 2

(A) Maternal exposure to microbiome-rich-environment can affect the development of fetal T cells. (B) The asthma history of the mother can affect the development of fetal T cells. CD14: Cluster of differentiation 14; TH1: T helper cell-1; TH2: T helper cell-2; TLR2: Toll-like receptor 2; Treg: Regulatory cells.

Figure 3

The interrelationship between the intestinal microbiome and respiratory microbiome.