Technical Reference #1685

1685.

Mechanical and Biochemical Modeling of Cortical Oscillations in Spreading Cells Maryna Kapustina; Gabriel E. Weinreb; Nancy Costigliola; Zenon Rajfur; Ken Jacobson; and Timothy C. Elstonz, Univeristy of North Carolina, Biophysical Journal, 94(1685), (2008)
Link To Paper

Abstract:
Actomyosin-based cortical contractility is a common feature of eukaryotic cells and is involved in cell motility cell division and apoptosis. In nonmuscle cells oscillations in contractility are induced by microtubule depolymerization during cell spreading. We developed an ordinary differential equation model to describe this behavior. The computational model includes 36 parameters. The values for all but two of the model parameters were taken from experimental measurements found in the literature. Using these values we demonstrate that the model generates oscillatory behavior consistent with current experimental observations. The rhythmic behavior occurs because of the antagonistic effects of calcium-induced contractility and stretchactivated calcium channels. The model makes several experimentally testable predictions: 1) buffering intracellular calcium increases the period and decreases the amplitude of cortical oscillations; 2) increasing the number or activity of stretch activated channels leads to an increase in period and amplitude of cortical oscillations; 3) inhibiting Ca21 pump activity increases the period and amplitude of oscillations; and 4) a threshold exists for the calcium concentration below which oscillations cease.

Materials & Methods:
Experimental Swiss 3T3 fibroblasts (American Type Culture Collection Rockville MD) were cultured under standard conditions (DMEM supplemented with 10% fetal bovine serum at 37 C with 5% CO2) with and without antibiotics in the medium (50 U/ml streptomycin and 50 U/ml penicillin). Cells were then plated on glass bottom 35 mmmicrocells (MatTek Ashland MA) with 1 mg/ ml of colcemid to depolymerize the microtubules. After 20 min the majority of cells were attached to the substratum. The behavior of nearly 500 cells was monitored at 10 s intervals for 6 h on a Diaphot 300 microscope (Nikon Melville NY) using phase contrast imaging and MetaMorph software (Molecular Devices Sunnyvale CA).

Microscopic Technique
Phase Contrast Microscopy

Cell Type(s)
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