ABSTRACT
Cell chirality is crucial for the chiral morphogenesis of biological tissues, yet its underlying mechanism remains unclear. Cell organelle polarization along multiple axes in a cell body, namely, apical-basal, front-rear, and left-right, is known to direct cell behavior such as orientation, rotation, and migration. Among these axes, the left-right bias holds significant sway in determining the chiral directionality of these behaviors. Normally, mouse myoblast (C2C12) cells exhibit a strong counterclockwise chirality on a ring-shaped micropattern, whereas they display a clockwise dominant chirality under Latrunculin A treatment. To investigate the relationship between multicellular chirality and organelle positioning in single cells, we studied the left-right positioning of cell organelles under distinct cell chirality in single cells via micropatterning technique, fluorescent microscopy, and imaging analysis. We found that on a "T"-shaped micropattern, a C2C12 cell adopts a triangular shape, with its nucleus-centrosome axis pointing toward the top-right direction of the "T." Several other organelles, including the Golgi apparatus, lysosomes, actin filaments, and microtubules, showed a preference to polarize on one side of the axis, indicating the universality of the left-right asymmetrical organelle positioning. Interestingly, upon reversing cell chirality with Latrunculin A, the organelles correspondingly reversed their left-right positioning bias, as suggested by the consistently biased metabolism and contractile properties at the leading edge. This left-right asymmetry in organelle positioning may help predict cell migration direction and serve as a potential marker for identifying cell chirality in biological models.
