The role of hepatocyte growth factor in mesenchymal stem cell-induced recovery in spinal cord injured rats

Abstract

Background: Mesenchymal stem cells (MSCs) have become a promising treatment for spinal cord injury (SCI) due to the fact that they provide a favorable environment. Treatment using MSCs results in a better neurological functional improvement through the promotion of nerve cell regeneration and the modulation of inflammation. Many studies have highlighted that the beneficial effects of MSCs are more likely associated with their secreted factors. However, the identity of the factor that plays a key role in the MSC-induced neurological functional recovery following SCI as well as its molecular mechanism still remains unclear. Methods: A conditioned medium (collected from the MSCs) and hepatocyte growth factor (HGF) were used to test the effects on the differentiation of neural stem cells (NSCS) in the presence of BMP4 with or without a c-Met antibody. In SCI rats, Western blot, ELISA, immunohistochemistry, and hematoxylin-eosin staining were used to investigate the biological effects of MSC-conditioned medium and HGF on nerve cell regeneration and inflammation with or without the pre-treatment using a c-Met antibody. In addition, the possible molecular mechanism (cross-talk between HGF/c-Met and the BMP/Smad 1/5/8 signaling pathway) was also detected by Western blot both in vivo and in vitro. Results: The conditioned medium from bone marrow-derived MSCs (BMSCs) was able to promote the NSC differentiation into neurons in vitro and the neurite outgrowth in the scar boundary of SCI rats by inhibiting the BMP/Smad signaling pathway as well as reduces the secondary damage through the modulation of the inflammatory process. The supplementation of HGF showed similar biological effects to those of BMSC-CM, whereas a functional blocking of the c-Met antibody or HGF knockdown in BMSCs significantly reversed the functional improvement mediated by the BMSC-CM. Conclusions: The MSC-associated biological effects on the recovery of SCI rats mainly depend on the secretion of HGF.

BMSC-CM prevents over-differentiation of NSCs to astrocytes by upregulating Smad 6 expression

“…It is generally thought that MSCs exert their biological effects in different models by secreting a large variety of factors and molecules [47][48][49][50]. In SCI rats, MSCs were able to improve neurological outcomes by promoting the regeneration of neurons and axon regrowth [51][52][53] through the inhibition of BMP/Smads signaling [5,27]. In the present study, it was found that the addition of BMSC-CM to NSCs increased the expression of Smad 6.…”

“…NSCs were cultured as described in our previous studies [27,28]. Cells were obtained from the subventricular zone of SD rats.…”

“…MSCs were cultured following the procedure described in our previous studies [27,28]. The cells were isolated from the bone marrow of Fischer 344 rats and were cultured in DMEM (low glucose, Hyclone) containing 10% fetal bovine serum (FBS) (Gibco, USA) and 1% antibiotic solution at a density of 1 × 10 6 cells/cm 2 .…”

“…The CM was prepared from a 90% con uence of passage 3 BMSCs, as described in previous studies [27,29]. Brie y, con uent BMSCs were cultured with a serum-free DMEM/F12 (Gibco, USA) medium for 48 h. The CM was harvested from different asks.…”

“…20191064), in accordance with the guidelines of the Declaration of Helsinki, revised in Edinburgh in 2000. The procedure details are outlined in our previous studies [27]. Brie y, a laminectomy was performed at the T10 level on female Wistar rats (6-8 weeks old, weighing 200-250 g).…”