DEPARTAMENTO DE CIÊNCIAS DA VIDA ... - Estudo Geral

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Figure 13 - Quantification of B-III tubulin(grey) and MyoD (black) by MSCs fluorescent intensity on
gradient hydrogels (from 1 to 11 kPa, filled squares) and normalized to the non-permissive static
hydrogels (1 and 11kPa each and only, open circles). Adapted from Tse and Engler, 2011.
In Figure 13 we can see that B-III tubulin and MyoD intensities were normalized
to MSC intensity on static 11 and 1 kPa hydrogels, respectively. The dashed line
indicates no change of the proteins in the non-permissive static hydrogels (Tse and
Engler, 2011).
This data (Figure 12 and 13) suggests that MSCs can remain plastic and express
specific lineage markers triggered by stiffness from a region in which they previous
resided, the so called “memory” (Tse and Engler, 2011).
I.3.3 - Effects of the stiffness on the MSCs stemness genes
Stiffness can regulate the differentiation potential of MSCs (Engler et al., 2006; Her et
al., 2013; Tse and Engler, 2011). The influence of stiffness on MSCs stemness was also
reported (Her, et al. 2013), namely by evaluating how MSCs marker react to stiffness.
Using 3-D Col–HA scaffolds of 1 and 10 kPa, hMSCS were cultured for 1 or 2 weeks and
then collected for qRT-PCR. From the results, they observed that the expression of
MSC stemness genes (including CD73, CD90 and CD105) was down-regulated during
culture, suggesting that the hMSCs in soft and stiff substrates started to differentiate
under various mechanical stimuli (Figure 14). The gene expression of representative
MSC surface markers remained at a low level after 2 weeks of culture. The gene
expression level of CD73, CD90, and CD105 in stiff substrate was significantly lower