SERPINE1 and infection: At low population density, LasI induces low production of 3OC12-HSL, whereas at high population density LasR binds its cognate AHL AI, and together they bind at promoter elements enhancing the production of virulence factors that are responsible for host tissue destruction during initiation of the infection process and also activates the transcription of lasI, rhlR. PAI1 is known to activate the Lux-R type transcription factor LasR and as a result, LasR-PAI1 triggers the production of various virulence factors such as LasB elastase, LasA protease, alkaline protease, exotoxin A, and LasR1.