One Scaffold - Different Organelles Sensors: pH-Activable Fluorescent Probes for Targeting Live Primary Microglial Cell Organelles

Abstract

Targeting live cell organelles is important for imaging and to understand and control specific biochemical processes. Typically, fluorescent probes with distinct structural scaffolds have been used for targeting specific cell organelle. Herein, we aimed to design modular one-step synthetic strategies using a common reaction intermediate to develop new lysosomal, mitochondrial and nucleus targeting pH-activable fluorescent probes that are all based on a single boron dipyrromethane analogs. The divergent cell organelle targeting was achieved by synthesizing pH-activable fluorescent probes with specific functional groups changes to the main scaffold resulting in differential fluorescence and pKa. Specifically, we show that the functional group transformation of the same scaffold influences cellular localization and specificity of pH-activable fluorescent probes in live primary microglial cells with pKas ranging from ~4.5-6.0. We introduce a structure-organelle-relationship (SOR) framework targeting the nucleus (NucShine), lysosomes (LysoShine) and mitochondria (MitoShine) in primary mouse microglial cells. This work will result in future applications of SOR beyond imaging to target and control organelle-specific biochemical processes in disease-specific models.