Wnt4‐modified NSC transplantation promotes functional recovery after spinal cord injury

Abstract

Spinal cord injury (SCI) can lead to severe motor and sensory dysfunction, yet there are no effective therapies currently due to the failure of reconstructing the interruption of the neuroanatomical circuit. While neural stem cell (NSC) transplantation has been considered a potential strategy to repair the neural circuit after SCI, the efficacy of this strategy remains unproven. The main reason is that most of the transplanted NSC differentiates into astrocyte rather than neuron in the microenvironment of SCI. Our results demonstrated that Wnt4 significantly promotes the differentiation of NSC into neuron by activating both β‐catenin and MAPK/JNK pathways and suppressing the activation of Notch signaling, which is acknowledged as prevention of NSC differentiation into neuron, through downregulating NICD expression, translocating and preventing the combination of NICD and RbpJ in nucleus. In addition, Wnt4 rescues the negative effect of Jagged, the ligand of Notch signaling, to promote neuronal differentiation. Moreover, in vivo study, transplantation of Wnt4‐modified NSC efficaciously repairs the injured spinal cord and recovers the motor function of hind limbs after SCI. This study sheds new light into mechanisms that Wnt4‐modified NSC transplantation is sufficient to repair the injured spinal cord and recover the motor dysfunction after SCI.

Transplantation of Wnt5a-modified NSCs promotes tissue repair and locomotor functional recovery after spinal cord injury

“…NSCs were obtained from the fetal brain of embryonic day 14 rats, which were extracted from pregnant Sprague-Dawley (SD) rats (Laboratory Animal Center of Sun Yat-Sen University, Guangzhou, China) [27][28][29] . NSCs were plated in a T25 culture flask (Corning, Acton, MA, 430639) containing maintenance medium consisting of Dulbecco's modified Eagle's medium/F12 nutrient mixture, 2% B27, 1% penicillin/streptomycin, 1% L-glutamine (Invitrogen, Carlsbad, CA, 11320033), 20 ng/mL fibroblast growth factor-2 (FGF-2) and 20 ng/mL epidermal growth factor (EGF) (PeproTech, Rocky Hill, NJ, 96-400-29, 96-AF-100-15).…”

“…To induce neuronal differentiation, cells were plated at a density of 2 × 10 5 cells/well in 6-or 12-well tissue culture plates and allowed to adhere for 24 h at 37°C, at which time cells were switched to neuronal differentiation medium consisting of basic medium supplemented with 2% B27, 1% penicillin/streptomycin, and 1% l-glutamine. The medium was changed every 2-3 days 29 .…”

“…Adult female SD rats (weighing 200-220 g, supplied by the Experimental Animal Center of Sun Yat-Sen University, Guangzhou, China) were used to establish an SCI animal model [27][28][29] . Behavioral and histological analyses were performed using previously described standard methods [30][31][32][33] and detailed in online supplementary materials.…”

Neural stem cells induce M2 polarization of macrophages through the upregulation of interleukin‑4

“…A number of clinical trials have reported the efficacy of the stem cell transplantation as a potential strategy to repair damaged tissue and recover locomotor functional after SCI (15,35,36). These studies demonstrated that the transplanted cells differentiate into neurons, which mainly rebuilt neural circuits to promote tissue repair and locomotor function recovery (37).…”

“…To induce neural differentiation, cells were plated at a density of 2x10 5 cells/well in 6-or 12-well tissue-culture plates and allowed to adhere for 24 h at 37˚C, at which time cells were switched to neural differentiated medium consisting of basic medium supplemented with 2% B27, 1% penicillin/streptomycin and 1% l-glutamine. The medium was changed every 2-3 days (14,15).…”