奈米工程與微系統研究所　書報討論

Seminar of Inst. NanoEngineering and MicroSystems

Chen Ting-Hsuan (陳定璿)

Department of Biomedical Engineering, City University of Hong Kong

Associate Professor

Chiral Mechanics of Micropatterned Cells

Abstract:

Cell chirality is an intrinsic, left-right (LR) -biased cell mechanics resulted from intracellular molecular handness. It can be seen by embryonic cells that establish LR body axis of animal body plan, visceral distribution, and overall handness of organ orientation. For specialized adult cells derived from somatic tissue, footprints of cell chirality can be still seen by their ability of generating cellular torque, migration with LR bias, or forming specific alignment in the multicellular level. Clearly, to give rise to such diversity, cell chirality should be coupled with cell differentiation. However, due to the lack of standard characterization platform, its evolvement during differentiation has been unknown. In this talk, we will report a series of approaches to characterize cell chiral mechanics. First, we developed a nanowire magnetoscope that reveals a rotating force – torque – exerted by cells. Internalized ferromagnetic nanowires were used to reflect the rotational force of cells, and we found that such cellular torque is biased with clockwise (CW) or counterclockwise (CCW) direction depending on cell types. In addition, we also applied micropatterned substrate and automated image processing to investigate the chiral mechanics of the nucleus rotation and orientation. Based on the analytical tools, we will discuss the cell chirality in relation to 1) actin configuration, 2) cell-substrate interaction, 3) cell-cell alignment, and 4) phenotypical dependence. At last, using hMSCs on micropatterned ECM protein as a model system, we report an early committed cell chirality during lineage specification. hMSCs exhibited an anticlockwise (ACW) -biased nucleus rotation on circular micropatterns, and such chirality was reversed to clockwise (CW) bias after adipogenic induction for only 6 days. Remarkably, Using latrunculin A (LatA) that forced the CW-biased actin filament recapturing the chiral actin upon adipogenic induction, adipogenic differentiation was up-regulated. More importantly, using self-organized cell orientation on micropatterned stripes as a model of morphogenesis, we found that cell orientation collectively evolved from positive to negative in only 3 days with adipogenic induction. Thus, the early differentiated chiral actin may serve as a mechanical precursor to engage the lineage commitment and to coordinate the chiral morphogenesis at early stage, suggesting an active role of cytoskeletal chirality in tissue formation.

15:30-17:20 on Oct. 7(Mon), 2019 at Room 108 of Eng. Building I

Host：Prof. Mei-Feng Lai mflai@mx.nthu.edu.tw Ext:33998

Contact：Ming-Wei Wang cenawang0216@gmail.com