Dynamic monitoring of changes in endothelial cell-substrate adhesiveness during leukocyte adhesion by microelectrical impedance assay

Abstract

Adhesion of leukocytes to endothelial cells in inflammation processes leads to changes of endothelial cell-substrate adhesiveness, and understanding of such changes will provide us with important information of inflammation processes. In this study, we used a noninvasive biosensor system referred to as real-time cell electronic sensor (RT-CES) system to monitor the changes in endothelial cell-substrate adhesiveness induced by human monoblastic cell line U937 cell adhesion in a dynamic and quantitative manner. This assay, which is based on cell-substrate impedance readout, is able to monitor transient changes in cell-substrate adhesiveness as a result of U937 cell adhesion. The U937 cell adhesion to endothelial cells was induced by lipopolysaccharide (LPS) in a dose-dependent manner. Although the number of adherent U937 cells to the endothelial cells was verified by a standard assay, the adhesiveness of endothelial cells after addition of U937 cells was monitored by the RT-CES system. Furthermore, focal adhesion kinase protein decrease and F-actin rearrangement in endothelial cells were observed after addition of U937 cells. Our results indicated that the adhesion of U937 cells to LPS-treated endothelial cells reduced the cell adhesiveness to the substrate, and such reduction might facilitate infiltration of leukocytes.

Differential expression of nitric oxide synthases in porcine aortic endothelial cells during LPS-induced apoptosis

“…Lipopolysaccharide treatment determined more intense staining in the perinuclear region in accordance with that observed by Iwakiri et al [19] and Zhang et al [20]. Additional investigation is necessary to clarify the functional significance of eNOS distribution after LPS treatment, taking into account the complex change in endothelial cell morphology induced by endotoxins [24,25]. …”

Microfluidic impedance‐based flow cytometry

“…The group of impedance-based instruments which cover the field of adherent cell surface measurements include several tools presently available in the market, with examples from Bionas and ACEA Biosciences (including the Roche xCELLigence System derived from ACEA), which monitors proliferation of adherent cells (53,54). These systems were recently summarized by Xi et al (55).…”

“…Compared with Coulter Counters (Z series, CASY), which usually measure the impedance signals using DC or low AC, microfluidic impedance flow cytometry (IFC) provides the possibility to perform impedance measurements at different frequencies covering a range of 100 kHz to 20 MHz. As already documented from various groups (18,51,52), it was shown that at such frequencies (starting from 1 MHz) other parameters (cellular membrane capacitance and cytoplasmic conductivity) can also be interrogated and provide additional information (besides number and size).The group of impedance-based instruments which cover the field of adherent cell surface measurements include several tools presently available in the market, with examples from Bionas and ACEA Biosciences (including the Roche xCELLigence System derived from ACEA), which monitors proliferation of adherent cells (53,54). These systems were recently summarized by Xi et al (55).…”

Digital Holography and Cell Studies

“…It is a real-time cell analyzer that measures living cells without labeling. Electric impedance allows measurements of cellular processes such as proliferation, cytotoxicity, invasion, migration and cell viability (Atienza et al, 2006;Boyd et al, 2008;Ge et al, 2009) and give results comparable to imaging methods in some ways. Different staining methods have been developed that enable cells to absorb light.…”