Engineered Lactiplantibacillus plantarum as a Biosensor Probe for the Lungs

Lungs are a frequent site for disease but are difficult to image and probe, potentially exacerbating lung disease, delaying diagnoses and impacting survival. Here, we demonstrate a low cost, minimally invasive method to probe the lungs for disease, using genetically engineered Lactiplantibacillus plantarum strain WCFS1. Genetically modified WCFS1 was delivered specifically to the lungs of mice, where it was shown to remain transcriptionally active for several hours and then be cleared without further colonization. WCFS1 was further modified to secrete nanoluciferase as a synthetic biomarker, which traveled from the bacteria in the lung to the urine where it was easily detected. The administered bacteria also secreted nano-luciferase upon detecting a specific peptide secreted by a mouse lung cancer cell line in vitro or in vivo from syngeneic tumors.