Stromal progenitor cells promote leukocyte migration through production of stromal-derived growth factor 1 α: a potential mechanism for stromal progenitor cell–mediated enhancement of cellular recruitment to wounds

Abstract

Background/Purpose Stromal progenitor cells (SPC) enhance tissue repair in a variety of injury models. However, the mechanisms by which SPCs facilitate tissue repair remain poorly understood. We hypothesized that SPC-enhanced tissue repair is, in part, because of SPC-mediated recruitment of circulating cells to areas of tissue injury. To test this, we examined the migration of leukocytes in response to SPC in vitro. Methods Leukocyte migration was assessed in response to SPC, SPC + transforming growth factor (TGF)- β1, or SPC + AMD3100 using a Transwell assay system (Corning, distributed by Fisher Scientific, Pittsburgh, PA). Supernatants were collected from lower chambers and analyzed for leukocyte content, leukocyte viability, and stromal-derived growth factor (SDF)-1 α concentration. Results Stromal progenitor cells increased leukocyte migration compared to media alone (450 ± 70 vs 112 ± 17 cells/ μL; P < .05). SPC treatment with TGF- β1 resulted in a 36% increase in leukocyte migration and correlated with an increase in SDF-1 α production. Treatment with AMD3100 resulted in inhibition of leukocyte migration. Conclusions Stromal progenitor cells promote leukocyte migration, and this appears to be mediated through SDF-1 α production. The SPC production of SDF-1 α may be modulated by other cytokines present in the microenvironment during wound healing. Together, these observations provide a potential mechanism by which SPC may augment healing through enhanced recruitment of inflammatory cells and tissue progenitor cells to areas of tissue injury.