β-Arrestin 2 Regulates Inflammatory Responses against Mycobacterium tuberculosis Infection through ERK1/2 Signaling

Abstract

Mycobacterium tuberculosis, the pathogen that causes tuberculosis, exhibits complex host–pathogen interactions. Pattern recognition receptors and their downstream signaling pathways play crucial roles in determining the outcome of infection. In particular, the scaffold protein β-arrestin 2 mediates downstream signaling of G protein–coupled receptors. However, the role of β-arrestin 2 in conferring immunity against M. tuberculosis has not yet been explored. We found that β-arrestin 2 was upregulated in the lesioned regions of lung tissues in patients with tuberculosis. M. tuberculosis infection upregulated β-arrestin 2 expression in human macrophages, and silencing of β-arrestin 2 significantly enhanced bactericidal activity by enhancing the expression of proinflammatory cytokines such as TNF-α. β-Arrestin 2 was shown to inhibit the activation of the TLR2/ERK1/2 pathway and its transcriptional regulation activity upon M. tuberculosis infection. Furthermore, β-arrestin 2 transcriptionally regulates TNF-α by binding to CREB1. These observations revealed that the upregulation of β-arrestin 2 is critical for M. tuberculosis to escape immune surveillance through an unknown mechanism. Our research offers a novel interference modality to enhance the immune response against tuberculosis by targeting β-arrestin 2 to modulate the TLR2–β-arrestin 2–ERK1/2–CREB1–TNF-α regulatory axis.