TITLE: “Characterizing distinct cell states based on stimulus-response dynamics.”
ABSTRACT: Macrophages show remarkable functional pleiotropy that is dependent on microenvironmental context. Prior studies have characterized how polarizing cytokines alter epigenetic or signaling mechanisms, but how they affect specific macrophage functions has not been characterized systematically. One hallmark function of macrophages is to mount immune-threat appropriate responses, in part via the signaling dynamics of transcription factor NFκB. Here, we measured single-cell nuclear NFκB trajectories in macrophages polarized into 6 states and stimulated with 8 different stimuli resulting in a vast dataset. Linear Discriminant Analysis revealed how NFκB signaling codons compose the immune threat level of stimuli, placing polarization states along a linear continuum between the M1/M2 dichotomy. Machine learning classification revealed losses of stimulus distinguishability with polarization, which reflect a switch from sentinel to effector functions. However, the stimulus response dynamics and discrimination patterns did not fit the M1/M2 continuum. Instead, our analysis suggests macrophage functional niches within a multi-dimensional polarization landscape.
