MiR-31 improves spinal cord injury in mice by promoting the migration of bone marrow mesenchymal stem cells

Abstract

Background Stem cell transplantation therapy is a potential approach for the repair of spinal cord injuries and other neurodegenerative diseases, but its effectiveness is hampered by the low rate of targeted migration of cells to the area of injury. The aim of this study was to investigate the effects of miR-31 on the migration of bone marrow mesenchymal stem cells (BMSCs) and the regulation of MMP-2 and CXCR4 expression in vitro and in vivo. Methods eGFP-expressing BMSCs were isolated and cultured for subsequent experiments. The experiments were divided into three groups: control group, miR-31agomir group, and miR-31antagomir group. Proliferation was analyzed using CCK-8 and flow cytometry; cell migration in vitro was analyzed using wound-healing and transwell assays. The mouse SCI model was prepared by the impact method, and cells were transplanted (3 groups, 12 per group). Relevant inflammatory factors were detected by ELISA. The BMS score was used to evaluate the functional recovery of the mouse spinal cord and the frozen section was used to analyze the cell migration ability in vivo. The in vitro and in vivo expression levels of MMP-2 and CXCR4 were evaluated by Western blot and immunohistochemical staining. Results In vitro experiments showed that cells in the miR-31agomir group exhibited enhanced cell proliferation (P<0.05, P<0.001) and migration (P<0.001) and upregulated protein expression levels of CXCR4 (P<0.01) and MMP-2 (P<0.001) compared with cells in the control group. The results of in vivo experiments showed that the expression of pro-inflammatory factors was reduced after cell transplantation treatment. Cells in the miR-31agomir group showed enhanced cell-targeted migration ability (P<0.001), improved the function of damaged tissues (P<0.001), and upregulated CXCR4 and MMP-2 expression compared to the control group (P<0.001). Conclusion Our experiment demonstrated that miR-31 could promote the migration of BMSCs and miR-31 could repair and improve the function of damaged tissues in SCI.

Combined transplantation of hiPSC-NSC and hMSC ameliorated neuroinflammation and promoted neuroregeneration in acute spinal cord injury

“…The results of our study showed a significant improvement in the M&N group on day 1 after combined stem cell transplantation, as reflected in video and the score of stepping. This finding is surprising at first sight but is in part consistent with previous study that reported a rapid response to treatment [ 31 , 52 ]. We speculate that this may be related to the synergistic effect of NSC and MSC, and their interaction in vivo may have contributed to the rapid physiological response and functional recovery.…”

“…Eighty-four nude mice were randomly divided into cell-free (PBS) and cell groups (hMSCs + hiPSC-NSC) (42 mice in each group), which are referred to as the Con and M&N group, respectively. Immediately after the SCI, 1 μl of PBS was injected into the injured spinal cord (1 mm rostral to the lesion epiCenter) [ 31 ] of 42 mice using a glass pipette at a rate of 0.5 μl/minute with a 10μl Hamilton syringe and a stereotaxic microinjector (RWD, Shenzhen, China). Using the same method, 42 mice were injected with 1 × 10 5 cells/μl (0.5 × 10 5 hMSCs and 0.5 × 10 5 iPSC-derived NSCs) in M&N group.…”

MSC based gene delivery methods and strategies improve the therapeutic efficacy of neurological diseases

“…Other potential treatment strategies using implanted MSCs include promoting neural differentiation (EGF, Shh and miR-124) [ 159 , 176 , 247 , 248 ]; enhancing proliferation (bFGF, PTEN, IGF-1, and Nice4, Fig. 6 ) [ 203 , [249] , [250] , [251] ]; increasing migration ability (ChABC, Snail, miR-31 and SDF-1α) [ 250 , [252] , [253] , [254] ]; inhibiting apoptosis (GIT1 and miR-21) [ 255 , 256 ]; reducing antioxidative stress (miR-200a) [ 256 ]; proangiogensis (miR-17-5p) [ 257 ]; and neurotrophic effect (CNTF, BDNF, miR-146a-5p and miR-383) [ [258] , [259] , [260] , [261] , [262] ]. The details of these transgenic MSCs for SCI treatment are summarized in Table 2 .…”

Biomaterial‐Based Gene Delivery to Central Nervous System Cells for the Treatment of Spinal Cord Injury

“…[ 183 ] While viral‐based vector systems have been the preferred method of delivery (e.g., lentiviral [ 201 ] ), the likelihood of triggering innate microglia‐mediated immune response as well as other risks [ 202 ] has seen the progressive increase in nonviral transfection methods as an attractive alternative. [ 203 ] Several studies have reported nanoparticle‐mediated transfection of different stem cell‐modifying cargoes including siRNA, [ 204 ] miRNA, [ 205 ] and mRNA [ 206 ] typically delivered to mesenchymal (MSC) [ 196,207 ] and NSC [172a,208] prior to implantation. Several studies have demonstrated good nanoparticle‐mediated transfection efficiency into stem cells [163b,204a,206,209] .…”

“…[163b,204a,206,209] Genes have been delivered that help increase cell survival under hypoxic conditions, for example, through delivery of fibroblast growth factor-2 [210] or heme oxygenase-1, [211] while others direct tissue homing through delivery of inflammation-associated adhesion ligands (e.g., PSGL-1 [212] ). Other approaches include enhancing cell migration to the injured cord through delivery of miR-31 [205] and directing the differentiation of NSCs to neurons through the delivery of siRNA targeting of transcription factors, e.g., Sox9, [204] or RE-1 silencing transcription factor REST. [213] A second, less explored in vivo approach is to enhance the regenerative potential of cord resident NSCs arising from the ependymal layers surrounding the central canal.…”