[R01] Immune signaling and antibacterial defenses controlled by mycobacterial PE/PPE proteins

Ente: National Institute of Allergy and Infectious Diseases

Scadenza: 2031-06-30

Importo max: 780.615 EUR

Paese: US

Descrizione

PROJECT SUMMARY Mycobacterium tuberculosis (Mtb) causes one of the deadliest infectious diseases worldwide, killing ~1.5 million people annually. With increasing antibiotic resistance, there is a critical need to develop novel therapeutics, but this requires a detailed mechanistic understanding of Mtb virulence strategies and Mtb-host interactions. The immune response to Mtb is initiated by macrophages, which are innate immune cells that engulf and attempt to kill Mtb. However, Mtb secretes 100+ proteins to block macrophages' antibacterial pathways. Despite this arsenal of secreted proteins, we have a severely limited mechanistic understanding of how Mtb uses its effectors to manipulate host cell biology. A major group of poorly understood Mtb-secreted proteins is the PE/PPEs, which include ~170 proteins encoded by an impressive 10% of the Mtb genome. The size of this strange protein family, paired with the exclusive presence of PE/PPEs in pathogenic mycobacteria, suggests they may play critical roles in establishing infection and mediating host-pathogen interactions. However, because PE/PPE genes are highly repetitive and likely redundant, it has remained unclear how each PE/PPE mechanistically contributes to Mtb infection. To gain insight into PE/PPEs' functions, we hypothesized that different PE/PPEs localize to different domains within the host cell, driven by localization signals found in PE/PPE proteins. Using available tools, we identified nuclear localization signals (NLS), mitochondrial targeting sequences (MTS), and cytoskeleton associated SH3 protein interaction domains. In validating their predicted localizations and interactions, we found several PE/PPEs with robust localization patterns suggestive of novel cellular functions. PE9 localized to the nucleus, PPE61 localized to mitochondria, and PPE15 localized to the nuclear envelope. We additionally found that these PE/PPEs altered cytokine responses, damaged mitochondrial, promoted Mtb survival, and/or promoted cell death, further demonstrating they play key roles modulating host cell biology to promote Mtb infection. Here, we propose to dissect the mechanisms by which these three PE/PPEs alter cell biology using complementary methods of introducing each PE/PPE: ectopic expression in macrophages, introduction of PE/PPE-coated latex beads, and infection with knockout and overexpression Mtb strains. This approach will allow us to tease apart the specific contribution of each PE/PPE to gene expression, mitochondrial function, cell death pathways, selective autophagy, and more. This study will reveal how uncharacterized Mtb effector proteins promote infection and will likely identify novel host response pathways critical for controlling Mtb and other bacterial pathogens. This knowledge will inform the development of future TB treatments, contributing to the eradication of this challenging and deadly infectious disease. Istituzione: RUTGERS BIOMEDICAL AND HEALTH SCIENCES PI: Samantha Lynn Bell Progetto: 1R01AI203335-01

Settori: National Institute of Allergy and Infectious Diseases

Vai al bando originale

Registrati gratis su Bandolo per trovare bandi compatibili con la tua azienda.