A Galvanotaxis Assay for Analysis of Neural Precursor Cell Migration Kinetics in an Externally Applied Direct Current Electric Field

Abstract

The discovery of neural stem and progenitor cells (collectively termed neural precursor cells) (NPCs) in the adult mammalian brain has led to a body of research aimed at utilizing the multipotent and proliferative properties of these cells for the development of neuroregenerative strategies. A critical step for the success of such strategies is the mobilization of NPCs toward a lesion site following exogenous transplantation or to enhance the response of the endogenous precursors that are found in the periventricular region of the CNS. Accordingly, it is essential to understand the mechanisms that promote, guide, and enhance NPC migration. Our work focuses on the utilization of direct current electric fields (dcEFs) to promote and direct NPC migration -a phenomenon known as galvanotaxis. Endogenous physiological electric fields function as critical cues for cell migration during normal development and wound repair. Pharmacological disruption of the trans-neural tube potential in axolotl embryos causes severe developmental malformations 1 . In the context of wound healing, the rate of repair of wounded cornea is directly correlated with the magnitude of the epithelial wound potential that arises after injury, as shown by pharmacological enhancement or disruption of this dcEF [2][3] . We have demonstrated that adult subependymal NPCs undergo rapid and directed cathodal migration in vitro when exposed to an externally applied dcEF. In this protocol we describe our lab's techniques for creating a simple and effective galvanotaxis assay for high-resolution, long-term observation of directed cell body translocation (migration) on a single-cell level. This assay would be suitable for investigating the mechanisms that regulate dcEF transduction into cellular motility through the use of transgenic or knockout mice, short interfering RNA, or specific receptor agonists/antagonists.

Electrical Stimulation Enhances Migratory Ability of Transplanted Bone Marrow Stromal Cells in a Rodent Ischemic Stroke Model

“…Some studies have indicated that direct current electrical fields or electrical stimulation enhance migratory ability of various type of cells like NSCs and MSCs in vitro [13-15]. In the present study, BMSCs implanted in the contralateral corpus callosum migrated towards the epidural cathode electrode.…”

“…There are some reports that electric fields may direct various types of cells in vitro [13-15]. Furthermore, electrical stimulation enhances migration of endogenous neural stem cells and cell proliferation in vivo [16, 17].…”

Utilizing Custom-designed Galvanotaxis Chambers to Study Directional Migration of Prostate Cells

“…Compared to other galvanotaxis chamber designs made in culture dishes 27,28 , there are several benefits to the current design. First, the glass surface is suitable for imaging and the coverglass with cells can be retrieved after galvanotaxis for immunostaining.…”

“…Third, the modified platinum electrodes are inert in the electric field. Compared to the silver electrodes as used in other galvanotaxis methods 27 , they do not break down or release metal ions to the medium, which reduces the cytotoxicity in galvanotaxis. Fourth, we may change the intervals of frame capturing, which helps us to monitor either fast or slow cell migration.…”

Linear Array of Multi-Substrate Tracts for Simultaneous Assessment of Cell Adhesion, Migration, and Differentiation

“…New technologies such as microfluidic chambers (13–18), capillary techniques (19,20), galvanotaxis assay (21–23), Radius CytoSelect Cell Migration Assay (24), electric cell substrate impedance sensing (ECIS) assay (25), scratch-wound assay (26), gap closure assay (27), and 3-D collagen/fibrin gels (28,29) have been developed to provide more in vivo–like conditions to assess a wide array of motility mechanisms. Most of these systems assess only one substrate at a time or depend on the adsorption capacity of the glass or the dispersion capacity of ink-jet printer nozzles (30,31).…”