Figure 1.
Spontaneous migration of Schwann cells from sciatic nerve explants.
(A) A model for sciatic nerve explants. (B) Identification of migrating Schwann cells away from sciatic nerve tissues by immunostaining. P-75 (green) and S-100 (red) are cell markers of Schwann cells. Toto-3 (blue) is labeled for nucleus. (C) Time-lapse images of migrating Schwann cells from sciatic nerve explants. White arrowheads indicated for example cell. Time, min; scale bars, 20 µm.
Figure 2.
Cultured Schwann cells displayed distinct motile phenotypes in single-cell migration assay.
(A–C) Time-lapse images of Schwann cells with distinct motile morphologies: unipolar (A), bipolar (B) and multipolar (C). (D) Histogram showing the average migration rates of each motile phenotype of Schwann cells. Time, min, scale bar, 20 µm. Data are mean ± sem. **P<0.01, significant difference compared with unipolar group, ##P<0.01, significant difference compared with bipolar group, one-way ANOVA with pairwise posthoc tests comparisons by Student-Newman-Keuls method.
Figure 3.
Distinct motile phenotypes of Schwann cells could transform into each other spontaneously.
The example cells were shown in a series of time-lapse images (A–C). (A) A Schwann cell with unipolar morphology gradually transformed into a bipolar phenotype. (B) A Schwann cell with bipolar morphology transformed into a unipolar phenotype. (C) A Schwann cell with multipolar morphology rapidly transformed into a bipolar phenotype. (D) Histogram showing the percentages of transformed Schwann cells in total observed cells. (E) A sample cell showing that one Schwann cell changed its direction of migration through morphological transformation. Time, min, scale bar, 20 µm.
Figure 4.
F-actin polymerization at the leading front was required for extension of leading process and soma translocation of Schwann cells.
(A) Distributions of F-actin (red) and microtubules (green) in Schwann cells by immunostaining. P-75 (blue) is a cell marker of Schwann cell. (B–D) Images of migrating Schwann cells before and after frontal application of a DMSO, as a control (B), or latrunculin A (LA, C) or Jasp (D) gradient. (E–F) Summary of the percentages of collapsed or reversed cells in total observed cells (E) and migration rates of soma (F) after frontal application of DMSO or LA (50 µM in the pipette) or CD (1 mM in the pipette) or Jasp (20 µM in pipette).White arrowheads indicated the direction of the micropipette. Time, min; scale bars, 20 µm. Data are mean ± s.e.m. **P<0.01, significant difference compared with control, ##P<0.01, significant difference compared with Jasp group, one-way ANOVA with pairwise posthoc tests comparisons by Student-Newman-Keuls method.
Figure 5.
Decreasing the front-to-rear difference of myosin II activity induced the collapse of leading front and reversed soma translocation of Schwann cells.
(A) Distributions of p-MLC (green) and Dil (red, a marker of membrane) in Schwann cells by immunostaining. P-75 (blue) is a cell marker of Schwann cell. (B–D) Images of migrating Schwann cells before and after frontal application of a DMSO (B), or ML-7 (C) or Y-27632 (D) gradient. (E–F) Summary of the percentages of collapsed or reversed cells in total observed cells (E) and migration rates of soma (F) after frontal application of a DMSO or ML-7(5 mM in the pipette) or BDM (200 mM in the pipette) or Y27632 (10 mM in the pipette) gradient. White arrowheads indicated the direction of the micropipette. Time, min; scale bars, 20 µm. Data are mean ± s.e.m. **P<0.01, significant difference compared with control, ##P<0.01, significant difference compared with Y-27632 group, one-way ANOVA with pairwise posthoc tests comparisons by Student-Newman-Keuls method.
Figure 6.
Increasing the front-to-rear difference of myosin II activity accelerated soma translocation of Schwann cells.
(A–B) Images of migrating Schwann cells before and after rear application of a DMSO (A), or ML-7 (B) gradient. (C–D) Images of migrating Schwann cells before and after frontal application of a DMSO (C), or Caly (D) gradient. (E) Summary of migration rate ratios (after/before) of soma under various conditions. White arrowheads indicated the direction of the micropipette. The micropipette was loaded with 5 mM ML-7, or 200 mM BDM, or 25 µM Caly. Time, min; scale bars, 20 µm. Data are mean ± s.e.m. For data from rear application, **P<0.01, significant difference compared with control, one-way ANOVA with pairwise posthoc tests comparisons by Student-Newman-Keuls method. For data from frontal application, **P<0.01, significant difference compared with control, Student's t-test.