Tumor prevention facilitates delayed transplant of stem cell‐derived motoneurons

Abstract

ObjectiveNerve injuries resulting in prolonged periods of denervation result in poor recovery of motor function. We have previously shown that embryonic stem cell‐derived motoneurons transplanted at the time of transection into a peripheral nerve can functionally reinnervate muscle. For clinical relevance, we now focused on delaying transplantation to assess reinnervation after prolonged denervation.MethodsEmbryonic stem cell‐derived motoneurons were transplanted into the distal segments of transected tibial nerves in adult mice after prolonged denervation of 1–8 weeks. Twitch and tetanic forces were measured ex vivo 3 months posttransplantation. Tissue was harvested from the transplants for culture and immunohistochemical analysis.ResultsIn this delayed reinnervation model, teratocarcinomas developed in about one half of transplants. A residual multipotent cell population (~ 6% of cells) was found despite neural differentiation. Exposure to the alkylating drug mitomycin C eliminated this multipotent population in vitro while preserving motoneurons. Treating neural differentiated stem cells prior to delayed transplantation prevented tumor formation and resulted in twitch and tetanic forces similar to those in animals transplanted acutely after denervation.InterpretationDespite a neural differentiation protocol, embryonic stem cell‐derived motoneurons still carry a risk of tumorigenicity. Pretreating with an antimitotic agent leads to survival and functional muscle reinnervation if performed within 4 weeks of denervation in the mouse.

An optogenetic cell therapy to restore control of target muscles in an aggressive mouse model of amyotrophic lateral sclerosis

“…Therefore, we investigated the T-cell receptor-β (TCR-β) targeting monoclonal antibody, mAb H57-597, which has previously been shown to effectively promote long-term heart allograft survival in mice ( Miyahara et al, 2012 ). In addition, since our findings indicated that immunosuppression results in a greater risk of tumour formation from carry-over pluripotent stem cells, differentiated ChR2 + motor neurons were also pre-treated with mitomycin-C (MMC; 2 μg/ml for 2 hr) prior to engraftment, to eliminate tumorigenic cells ( Magown et al, 2016 ), to further enhance the translational potential. MMC-treated ChR2 + motor neurons were unilaterally engrafted into the tibial nerve of symptomatic SOD1 G93A mice (aged 95.7±4.6 days) in conjunction with transient H57-597 mAb delivery (1 mg, kg-1; i.p.…”

A cell therapy approach to prevent muscle atrophy and paralysis in an aggressive mouse model of ALS

“…Therefore, we investigated the T-cell receptor-β (TCR-β) targeting monoclonal antibody, mAb H57-597, which has previously been shown to effectively promote long-term heart allograft survival in mice 28 . In addition, since our ndings indicated that immunosuppression results in a greater risk of tumour formation from carry-over pluripotent stem cells, differentiated ChR2 + motor neurons were also pretreated with mitomycin-C (MMC; 2 μg/ml for 2 hrs) prior to engraftment, to eliminate tumorigenic cells 29 , to further enhance the translational potential. MMC-treated ChR2 + motor neurons were unilaterally engrafted into the tibial nerve of symptomatic SOD1 G93A mice (aged 95.7 ±4.6 days) in conjunction with transient H57-597 mAb delivery (1μg, kg -1 ; i.p.…”

Microfluidic chip for label-free removal of teratoma-forming cells from therapeutic human stem cells

“…However, despite the promise of hiPSCs derived cells to treat disease, tumorigenicity of residual pluripotent-like cells in differentiated stem cells remains a concern [24,25]. At present, numerous techniques have been applied to remove teratoma-forming potential from hiPSC-derived products, such as pretreatment with antimitotic agents and delayed transplant [26], sorting with flourescent activated cell sorting (FACS) [27], magnetic activated cell sorting (MACS) [28], introduction of inducible suicide genes [29], and complete differentiation into mature dopaminergic neurons [30]. Unfortunately, each of these methods have limitations.…”

“…Pretreatment with antimitotic agents and delayed transplant or complete differentiation into mature dopaminergic neurons increases turn-around time to derive therapeutic cells, and could make it difficult to transplant cells during the short optimal timing of transplantation in the subacute phase [31]. Although inducible suicide genes respond in 95% of cells , they are unlikely to eliminate teratoma because as few as 2 embryonic stem cells in two million non-neoplastic cells are capable of forming tumors in 60% of the transplants [26,29]. Additionally, FACS and MACS have thus far proven insufficient to eliminate teratoma-forming potential and both require pre-labeling cells with antibodies, which could interfere with proliferation and differentiation [27,28].…”