When Infection Meets Inflammation: Listeria monocytogenes and Host Signaling Pathways

Listeria monocytogenes (L. monocytogenes) is a significant zoonotic pathogen responsible for listeriosis, a foodborne infection with high mortality. The inflammasome, an innate immune complex, plays a critical role in controlling pathogenic infections through its rapid inflammatory output. During L. monocytogenes infection, pore-forming toxins such as listeriolysin-O and flagellin are quickly recognized by pattern recognition receptors (PRRs), triggering inflammatory responses and activating the host's anti-infection immunity. However, excessive or chronic inflammasome activation and subsequent interleukin-1β (IL-1β) release are implicated in the pathogenesis of L. monocytogenes. Although inflammasome activation is an effective defense against L. monocytogenes, the bacterium has evolved multiple mechanisms to inhibit this immune pathway. Hence, research on inflammasomes activation is crucial for better understanding the pathogenic mechanism of L. monocytogenes. In this review, we highlight recent advances in the understanding of the molecular mechanisms of inflammasome activation by L. monocytogenes infection. We then discuss advances in the role of the inflammasome pathway in the pathogenesis of L. monocytogenes, along with an overview of the applications of inflammasome inhibitors. Extensive studies into the mechanisms by which L. monocytogenes activates the inflammasome could lead to the discovery of novel therapeutic targets and strategies to fight L. monocytogenes infections.