Fig. 1
From: Cell shape information is transduced through tension-independent mechanisms
Podocytes differentiate in response to shape signals. a (Left) Scanning electron micrograph of in vivo podocytes showing distinct processes that branch out of a central cell body; (Right) representative images of cells cultured on unpatterned glass, box, and channel micropatterns of the 3-D biochips. Cells were stained for F-actin (red) and nuclei (blue). All scale bars are 20 μm. b mRNA expression levels measured by RT-PCR for physiologically essential proteins in podocytes revealed an increase in expression of nine out of eleven transcripts for cells plated on the channel micropatterns with a median increase of 87% (mean fold change of 2.8 ± 0.9; p < 0.05 vs. UNP; one-way ANOVA followed by a post hoc Tukey test). Cells in box patterns showed a median change of 7% with an increase in six and a decrease in five transcripts (mean fold change of 1.4 ± 0.3; p = ns vs. UNP). Heatmap represents the average expression levels from four independent experiments with two slides in each group. c Representative immunofluorescence images of physiologically essential proteins in podocytes plated on unpatterned and patterned surfaces. The proteins are organized into “slit diaphragm proteins” nephrin, podocin, and neph1 (upper row), “actin-bundling proteins” F-actin, synaptopodin, and α-actinin-4 (middle row), and “control proteins” phospholipase-C-ε and Fyn (lower row). d Summary of whole-cell fluorescence intensity fold change and localization ratio (ratio of fluorescence intensity within peripheral processes vs. cell body) in micropatterned podocytes. Values given as mean ± SEM; n = 80, chosen randomly from eight different slides cultured independently at different times (*p < 0.01 vs. UNP; one-way ANOVA followed by a post hoc Tukey test). e Representative immunofluorescent confocal volume scans of podocytes cultured on shallow (1 μm) and deep (5 μm) channel patterns showing nephrin (green), F-actin (red) and nuclei (blue). On biochips with shallow micropatterns, cells did not produce high aspect ratio processes enriched for nephrin. In contrast, clear enrichment was observed in deep channels. Hence, 3-D shape is necessary for the localization phenotype
