imaging-cleared-embryonic-postnatal-hearts-at-single-cell

Imaging Cleared Embryonic and Postnatal Hearts at Single-cell Resolution

Single clonal tracing and analysis at the whole-heart level can determine cardiac progenitor cell behavior and differentiation during cardiac development, ...

Albany Medical College

The development of the vertebrate body plan with left-right (LR) asymmetry (also known as handedness and chirality) requires the emerging chiral morphogenesis of epithelial cells at specific embryonic stages. In this process, cell-cell adhesions coordinate cellular organization and collective cell migration, and are critical for the directional looping of developing embryonic organs. However, the underlying biophysical mechanism is not yet well understood. Here we modeled normal and delayed epithelial LR symmetry breaking with patterned epithelial chiral morphogenesis on microscale lines with various widths. The patterned cells exhibited biased migration wherein those on opposing boundaries migrated in different directions. Disrupting adherens junctions with ethylene glycol tetraacetic acid (EGTA) resulted in a decrease in velocity difference in opposing boundaries as well as the associated biased cell alignment, along with an increase in the overall random motion. Altering the distance between the opposing boundaries did not significantly alter alignment, but significantly disturbed the velocity profile of the cell migration field. Further examination of cell polarity indicated that disruption of adherens junctions did not affect cell polarization on the boundaries, but decreased the transmission of chiral bias into the interior region of the epithelial cell sheet. Overall, our results demonstrated the dependence of the scale of collective cell migration on the strength of cell-cell adhesion, and its effects on the chirality of a multicellular structure through mediating cell polarity in the vicinity of geometric boundaries. This study demonstrated that our 2D microscale system provides a simple yet effective tool for studying the influence of collective cell migration on LR symmetry breaking, and possibly for fetal drug screening to prevent birth defects related to alteration in cell-cell adhesion.

Inhibition of cell-cell adhesion impairs directional epithelial migration on micropatterned surfaces.

The cardiac trabeculae are sheet-like structures extending from the myocardium that function to increase surface area. A lack of trabeculation causes embryonic lethality due to compromised cardiac function. To understand the cellular and molecular mechanisms of trabecular formation, we genetically labeled individual cardiomyocytes prior to trabeculation via the brainbow multicolor system and traced and analyzed the labeled cells during trabeculation by whole-embryo clearing and imaging. The clones derived from labeled single cells displayed four different geometric patterns that are derived from different patterns of oriented cell division (OCD) and migration. Of the four types of clones, the inner, transmural, and mixed clones contributed to trabecular cardiomyocytes. Further studies showed that perpendicular OCD is an extrinsic asymmetric cell division that putatively contributes to trabecular regional specification. Furthermore, N-Cadherin deletion in labeled clones disrupted the clonal patterns. In summary, our data demonstrate that OCD contributes to trabecular morphogenesis and specification.

Article	Year
Inhibition of cell-cell adhesion impairs directional epithelial migration on micropatterned surfaces. Integrative biology : quantitative biosciences from nano to macro\| PubMed ID: 25923643	2015
Single-Cell Lineage Tracing Reveals that Oriented Cell Division Contributes to Trabecular Morphogenesis and Regional Specification. Cell reports\| PubMed ID: 27052172	2016

David Shieh

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