Minimal impact electro-injection of cells undergoing dynamic shape change reveals calpain activation

作者：Lewis Kimberley J; Masterman Benjamin; Laffafian Iraj; Dewitt Sharon; Campbell Jennie S; Hallett Maurice B^*

来源：Biochimica et Biophysica Acta-Molecular Cell Research, 2014, 1843(6): 1182-1187.

DOI：10.1016/j.bbamcr.2014.02.020

• Cell spreading
• Chemokinesis
• Cytosolic Ca2+
• Neutrophil
• Phagocytosis

The ability of neutrophils to rapidly change shape underlies their physiological functions of phagocytosis and spreading. A major problem in establishing the mechanism is that conventional microinjection of substances and indicators interferes with this dynamic cell behaviour. Here we show that electroinjection, a %26quot;no-touch%26quot; point-and-shoot means of introducing material into the cell, is sufficiently gentle to allow neutrophils to be injected whilst undergoing chemokinesis and spreading without disturbing cell shape change behaviour. Using this approach, a fluorogenic calpain-1 selective peptide substrate was introduced into the cytosol of individual neutrophils undergoing shape changes. These data showed that (i) physiologically elevated cytosolic Ca2+ concentrations were sufficient to trigger calpain-1 activation, blockade of Ca2+ influx preventing calpain activation and (ii) calpain-1 activity was elevated in spreading neutrophil. These findings provide the first direct demonstration of a physiological role for Ca2+ elevation in calpain-1 activation and rapid cell spreading. Electroinjection of cells undergoing dynamic shape changes thus opens new avenues of investigation for defining the molecular mechanism underlying dynamic cell shape changes.

• 出版日期2014-6