Dataset Information

Quantitative multicolor compositional imaging resolves molecular domains in cell-matrix adhesions.

ABSTRACT:

Background

Cellular processes occur within dynamic and multi-molecular compartments whose characterization requires analysis at high spatio-temporal resolution. Notable examples for such complexes are cell-matrix adhesion sites, consisting of numerous cytoskeletal and signaling proteins. These adhesions are highly variable in their morphology, dynamics, and apparent function, yet their molecular diversity is poorly defined.

Methodology/principal findings

We present here a compositional imaging approach for the analysis and display of multi-component compositions. This methodology is based on microscopy-acquired multicolor data, multi-dimensional clustering of pixels according to their composition similarity and display of the cellular distribution of these composition clusters. We apply this approach for resolving the molecular complexes associated with focal-adhesions, and the time-dependent effects of Rho-kinase inhibition. We show here compositional variations between adhesion sites, as well as ordered variations along the axis of individual focal-adhesions. The multicolor clustering approach also reveals distinct sensitivities of different focal-adhesion-associated complexes to Rho-kinase inhibition.

Conclusions/significance

Multicolor compositional imaging resolves "molecular signatures" characteristic to focal-adhesions and related structures, as well as sub-domains within these adhesion sites. This analysis enhances the spatial information with additional "contents-resolved" dimensions. We propose that compositional imaging can serve as a powerful tool for studying complex multi-molecular assemblies in cells and for mapping their distribution at sub-micron resolution.

SUBMITTER: Zamir E

PROVIDER: S-EPMC2270910 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Adhesion between cardiac myocytes is essential for the heart to function as an electromechanical syncytium. Although cell-matrix and cell-cell adhesions reorganize during development and disease, the hierarchical cooperation between these subcellular structures is poorly understood. We reasoned that, during cardiac development, focal adhesions mechanically stabilize cells and tissues during myofibrillogenesis and intercalated disc assembly. As the intercalated disc matures, we postulated that focal adhesions disassemble as systolic stresses are transmitted intercellularly. Finally, we hypothesized that pathological remodeling of cardiac microenvironments induces excessive mechanical loading of intercalated discs, leading to assembly of stabilizing focal adhesions adjacent to the junction. To test our model, we engineered ?tissues composed of two ventricular myocytes on deformable substrates of tunable elasticity to measure the dynamic organization and functional remodeling of myofibrils, focal adhesions, and intercalated discs as cooperative ensembles. Maturing ?tissues increased systolic force while simultaneously developing into an electromechanical syncytium by disassembling focal adhesions at the cell-cell interface and forming mature intercalated discs that transmitted the systolic load. We found that engineering the microenvironment to mimic fibrosis resulted in focal adhesion formation adjacent to the cell-cell interface, suggesting that the intercalated disc required mechanical reinforcement. In these pathological microenvironments, ?tissues exhibited further evidence of maladaptive remodeling, including lower work efficiency, longer contraction cycle duration, and weakened relationships between cytoskeletal organization and force generation. These results suggest that the cooperative balance between cell-matrix and cell-cell adhesions in the heart is guided by an architectural and functional hierarchy established during development and disrupted during disease.