LncRNA-GAS5 promotes spinal cord repair and the inhibition of neuronal apoptosis via the transplantation of 3D printed scaffold loaded with induced pluripotent stem cell-derived neural stem cells.

Background: Stem cell transplantation has been increasingly used for spinal cord repair, and some achievements have been made. However, limited stem cell sources as well as immune rejection and ethical issues have restricted its wide application. Therefore, to achieve further breakthroughs regarding the application of stem cell transplantation to treat spinal cord injury (SCI), it is important to develop a stem cell line that can effectively avoid immune rejection and ethical issues.

Methods: Urine cells (UCs) were induced to differentiate into induced pluripotent stem cells (iPSCs), which then further differentiated into neural stem cells (NSCs). Relevant tests were performed, and three-dimensional (3D) printed scaffolds were prepared. Thirty C57BL/6 mice were divided into 5 groups based on a random number table: a sham group, an SCI group, an SCI + control group, an SCI + siNC group, and an SCI + siGAS5 group (n=6). The latter 4 groups replicated SCI models. Mice in the SCI + control group were transplanted with 3D scaffolds loaded with iPSC-derived NSCs (iPSd-NSCs). Mice in the SCI + siNC group and the SCI + siGAS5 group were transplanted with scaffolds loaded with iPSd-NSCs-siNC and 3D scaffolds loaded with iPSd-NSCs-siGAS5, respectively. Mice in the other groups were injected with the same amount of normal saline. Hematoxylin-eosin staining was used to observe the histopathology of the injured spinal cord, the Basso-Mouse Scale was used to assess the motor function of the hind limbs of the mice, and Western blot was used to detect the expression of apoptosis-related proteins after SCI.

Results: iPSd-NSCs were successfully induced and differentiated, and 3D printed heparin sulfate-collagen scaffolds were prepared, inside which a 3D loose porous structure was shown by electron microscopy. Morphological observations showed that iPSd-NSC transplantation improved SCI in mice, while GAS5 silencing inhibited the reparative effect of iPSd-NSC transplantation on SCI in mice. Western blot results indicated that iPSd-NSC transplantation significantly increased the expression level of B cell lymphoma/leukemia-2 (Bcl-2) (P<0.01) but decreased the expression levels of Bcl-2 associated X protein, cytochrome C, and cleaved caspase-3 (P<0.001).

Conclusions: The overexpression of lncRNA-GAS5 can promote spinal cord repair and inhibit neural apoptosis via the transplantation of 3D printed scaffolds loaded with iPSd-NSCs.