Extracellular Vesicles and Their Role in Lung Infections

Abstract

Lung infections are one of the most common causes of death and morbidity worldwide. Both bacterial and viral lung infections cause a vast number of infections with varying severities. Extracellular vesicles (EVs) produced by different cells due to infection in the lung have the ability to modify the immune system, leading to either better immune response or worsening of the disease. It has been shown that both bacteria and viruses have the ability to produce their EVs and stimulate the immune system for that. In this review, we investigate topics from EV biogenesis and types of EVs to lung bacterial and viral infections caused by various bacterial species. Mycobacterium tuberculosis, Staphylococcus aureus, and Streptococcus pneumoniae infections are covered intensively in this review. Moreover, various viral lung infections, including SARS-CoV-2 infections, have been depicted extensively. In this review, we focus on eukaryotic-cell-derived EVs as an important component of disease pathogenesis. Finally, this review holds high novelty in its findings and literature review. It represents the first time to cover all different information on immune-cell-derived EVs in both bacterial and viral lung infections.

Keywords: COVID-19; EVs; bacterial infection; biomarker; exosomes; extracellular vesicles; lung infection.

Figure 1

Biogenesis of extracellular vesicles (EVs). Biogenesis of both exosomes (50–150 mm) and ectosomes (50–10,000 mm) from healthy cells. Exosomes are budding from early endosomes after cargo sorting, where multivesicular bodies are formed, which then give rise to exosomes. On the other hand, ectosomes or microparticles are bigger particles that are budded through the cell membrane carrying various cargos.

Figure 2

Exosome function in lung infections (A); bacterial lung infection: In bacterial lung infections, epithelial cells, macrophages, and endothelial cells play an important role in pathogenesis through their exosomal cargo. Various cytokines and chemokine production due to exosome effects are shown. (B) Viral lung infection: The contribution of exosomal cargo from macrophages, epithelial cells, monocytes, and dendritic cells is depicted. Various cytokines and chemokine production due to exosome effects are shown. Upward arrows indicate increased production of various chemokines and cytokines.

Figure 3

Contribution of exosomes in COVID-19 infection. Exosomes produced due to COVID-19 infection and their role in the pathogenesis of the infection. Epithelial exosomes can cause blockade of entry and triggering of inflammasome. Platelet- and serum-derived exosomes can lead to the activation of thrombin, activation of the fibril in the nervous system, and inflammation of the heart. Upward arrows indicate increased production of various chemokines and cytokines.