Transplantation of sh-miR-199a-5p-Modified Olfactory Ensheathing Cells Promotes the Functional Recovery in Rats with Contusive Spinal Cord Injury

Abstract

MicroRNAs (miRNAs) function as gene expression switches, and participate in diverse pathophysiological processes of spinal cord injury (SCI). Olfactory ensheathing cells (OECs) can alleviate pathological injury and facilitate functional recovery after SCI. However, the mechanisms by which OECs restore function are not well understood. This study aims to determine whether silencing miR-199a-5p would enhance the beneficial effects of the OECs. In this study, we measured miR-199a-5p levels in rat spinal cords with and without injury, with and without OEC transplants. Then, we transfected OECs with the sh-miR-199a-5p lentiviral vector to reduce miR-199a-5p expression and determined the effects of these OECs in SCI rats by Basso–Beattie–Bresnahan (BBB) locomotor scores, diffusion tensor imaging (DTI), and histological methods. We used western blotting to measure protein levels of Slit1, Robo2, and srGAP2. Finally, we used the dual-luciferase reporter assay to assess the relationship between miR-199-5p and Slit1, Robo2, and srGAP2 expression. We found that SCI significantly increased miR-199a-5p levels ( P < 0.05), and OEC transplants significantly reduced miR-199a-5p expression ( P < 0.05). Knockdown of miR-199a-5p in OECs had a better therapeutic effect on SCI rats, indicated by higher BBB scores and fractional anisotropy values on DTI, as well as histological findings. Reducing miR-199a-5p levels in transplanted OECs markedly increased spinal cord protein levels of Slit1, Robo2, and srGAP2. Our results demonstrated that transplantation of sh-miR-199a-5p-modified OECs promoted functional recovery in SCI rats, suggesting that miR-199a-5p knockdown was more beneficial to the therapeutic effects of OEC transplants. These findings provided new insights into miRNAs-mediated therapeutic mechanisms of OECs, which helps us to develop therapeutic strategies based on miRNAs and optimize cell therapy for SCI.

Improved tissue integrity after alginate treatment in rat spinal cord injury: evidence from ex vivo diffusion tensor imaging

“…These finding are consistent with presumed structural changes following successful treatment such as restoring axonal integrity and remyelination. Similar findings of increased FA after treatment were recently reported by Gao et al (2020). Interestingly, based on the provided SNR data by Ellingson et al (2008a), we managed to obtain comparable image quality using ex vivo DTI in magnetic field far below preclinical 9.4 T standard as was proposed by de Graff et al (2006).…”

“…3). The same approach was used by Gao et al (2020) to present only a visual qualitative parameter of applied treatment. However, tractography can provide additional set of parameters with respect to fiber length and fiber number together with tract-based ROI selection with following DTI metrics evaluation.…”

“…However, far less DTI studies were related to assessing the spinal cord tissue structure after the therapeutic intervention. Only recently diffusion tensor imaging was used to assess stem cell transplantation in the areas distal to the lesion in rat spinal cord injury model (Jirjis et al 2017) and in the most recent study the DTI derived FA showed correlation with functional outcome after olfactory ensheathing cells administration in rats with contusive SCI (Gao et al 2020).…”

Transplantation of olfactory ensheathing cells decreases local and serological monocyte chemoattractant protein 1 level during the acute phase of rat spinal cord injury

“…However, the drastically changing inflammatory environment during this period could affect cell survival and differentiation, which impairs therapeutic effects and causes experimental biases. To avoid controversy, our previous study showed an adequate survival rate of OECs transfected with GFP lentivirus at 7 days after transplantation [43]. Transcriptional upregulation of Cxcl9 and Nos2 was found after OECs transplantation, implying that acute OECs injection might trigger immune rejection against foreign graft cells in the spinal cord [39].…”

MicroRNAs: emerging driver of cancer perineural invasion

“…Bao et al illustrated that miR-199a-5p could defend the spinal cord against ischemia/reperfusion-mediated injury through inhibiting ECE1 expression in rats [ 136 ]. However, Gao et al revealed that decreased miR-199a protected against neuronal damage and contributed to functional recovery through upregulation of SIRT1, deacetylation of p53 and the activation of mammalian-target-of-rapamycin signaling pathway in Spinal Cord Injury of rats [ 137 – 139 ]. Inhibition of miR-199a could encourage neuroprotection through upregulating Sirtl expression in the brain ischemic tolerance of rats [ 140 ].…”