Abstract
Here we provide demonstration that image mean square displacement (iMSD) analysis is a fast and robust platform to address living matter dynamic organization at the level of sub-cellular nanostructures (e.g. endocytic vesicles, early/late endosomes, lysosomes), with no a-priori knowledge of the system, and no need to extract single trajectories. From each iMSD, a unique triplet of average parameters (namely: diffusivity, anomalous coefficient, size) are extracted and represented in a 3D parametric space, where clustering of single-cell points readily defines the structure “dynamic fingerprint”, at the whole-cell-population level. We demonstrate that different sub-cellular structures segregate into separate regions of the parametric space. The potency of this approach is further proved through application to two exemplary, still controversial, cases: i) the intracellular trafficking of lysosomes, comprising both free diffusion and directed motion along cytoskeletal components, and ii) the evolving dynamic properties of macropinosomes, passing from early to late stages of intracellular trafficking. We strongly believe this strategy may represent a flexible, multiplexed platform to address the dynamic properties of living matter at the sub-cellular level, both in the physiological and pathological state.
Highlights
A distinguishing feature of eukaryotic cells at the sub-cellular spatial scale is that of being organized into membrane-enclosed, sub-micrometric, and dynamic organelles or compartments, such as endocytic/secretory vesicles, early-late endosomes, lysosomes, mitochondria, etc.[1]
We propose the iMSD analysis as a promising tool to address the characteristic structural and dynamic properties of sub-cellular nanoscopic compartments in living cells
A few examples: derailed endocytosis is commonly found in cancer cells[4,5], altered granule trafficking is found in β-cells exposed to Type-2-Diabetes-mimicking conditions[36], enlarged lysosomes packed with twisted microtubules are a recognized hallmark of globoid cell leukodystrophy or galactosylceramide lipidosis[37], abnormalities in the endosomal-lysosomal system are observed in neurodegenerative diseases, especially Alzheimer’s disease (AD)[27]
Summary
A distinguishing feature of eukaryotic cells at the sub-cellular spatial scale is that of being organized into membrane-enclosed, sub-micrometric, and dynamic organelles or compartments, such as endocytic/secretory vesicles, early-late endosomes, lysosomes, mitochondria, etc.[1]. We show the applicability of this method to one of the natural conditions of living matter at the sub-cellular spatial scale, that of sub-micrometric, dynamic structures or compartments deputed to shuttle molecules around the cell To this end, we used fluorescently labelled variants of the major structures involved in endocytic processes (namely: caveolae, clathrin-coated vesicles, and macropinosomes) and in the subsequent intracellular processing of internalized cargoes (namely: early endosomes, late endosomes, and lysosomes). We used fluorescently labelled variants of the major structures involved in endocytic processes (namely: caveolae, clathrin-coated vesicles, and macropinosomes) and in the subsequent intracellular processing of internalized cargoes (namely: early endosomes, late endosomes, and lysosomes) For each of these structures, the local diffusivity (Dmicro, hereafter Dm), the anomalous-diffusion coefficient (α), and the offset parameter (σ02) are extracted by fitting the iMSD plot and represented in a parametric 3D space.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
