Fibroblast activation protein (FAP) is essential for the migration of bone marrow mesenchymal stem cells through RhoA activation.

ABSTRACT:

Background

The ability of human bone marrow mesenchymal stem cells (BM-MSCs) to migrate and localize specifically to injured tissues is central in developing therapeutic strategies for tissue repair and regeneration. Fibroblast activation protein (FAP) is a cell surface serine protease expressed at sites of tissue remodeling during embryonic development. It is also expressed in BM-MSCs, but not in normal tissues or cells. The function of FAP in BM-MSCs is not known.

Principal findings

We found that depletion of FAP proteins significantly inhibited the migration of BM-MSCs in a transwell chemotaxis assay. Such impaired migration ability of BM-MSCs could be rescued by re-expressing FAP in these cells. We then demonstrated that depletion of FAP activated intracellular RhoA GTPase. Consistently, inhibition of RhoA activity using a RhoA inhibitor rescued its migration ability. Inhibition of FAP activity with an FAP-specific inhibitor did not affect the activation of RhoA or the migration of BM-MSCs. Furthermore, the inflammatory cytokines interleukin-1beta (IL-1?) and transforming growth factor-beta (TGF-?) upregulated FAP expression, which coincided with better BM-MSC migration.

Conclusions

Our results indicate FAP plays an important role in the migration of BM-MSCs through modulation of RhoA GTPase activity. The peptidase activity of FAP is not essential for such migration. Cytokines IL-1? and TGF-? upregulate the expression level of FAP and thus enhance BM-MSC migration.

SUBMITTER: Chung KM 

PROVIDER: S-EPMC3923824 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature