Tension Regulation of the Cell Surface in Wound Healing

Dey, Swagata (2015) Tension Regulation of the Cell Surface in Wound Healing. Masters thesis, Indian Institute of Science Education and research Kolkata.

PDF (MS dissertation of Swagata Dey (13IP018)) Swagata_Dey_13IP018.pdf - Submitted Version Restricted to Repository staff only Download (2MB)

Abstract

Collective cell migration is one of the most important mechanisms involved in wound healing. In my MS thesis I intend to revisit the problem of wound healing with the tension regulation of the cell surface (plasma-membrane and cortical actin) in mind. While the leading edge throws out lamelipodia, the cells in the inner layers, away from the wound move in a collective form. Tension in the cell interface is due to both bilayer tension (increased by exocytosis, decreased by endocytosis) and cortical tension (increased by increased myosin activity). For a particular connection (between two adjoining cells parallel to the wound), one is the trailing edge of one cell while the other is the leading edge. Here I am focusing on how any directionality in membrane trafficking is setup during wound healing and how the cortical actin is redistributed. The cells near the wound have a particular goal, i.e., filling up the space that has been accidentally created. There is some background information available about the cell getting flattened during the collective cell migration. So we have also looked at the gradual flattening of cells during wound healing. To address these questions, I have performed wound healing experiments in HeLa cells looking both at the leading edge and cells in inner layers. I started by calibrating the microscope and writing MATLAB codes for analysis that would be helpful in analyzing data at the later time point of the work. I have characterized the timescale for the sealing of the wound. To look at directionality in endo/exocytosis I have labeled “some” cells with FM or taken time-lapse DIC images and also Nile Red stained images and to measure cytoskeleton distribution I have fixed cells and labeled them with phalloidin-FITC. For looking at flattening of cell, we have taken Z-stacks in DIC.

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