A novel cell transplantation protocol and its application to an ALS mouse model.

Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disease, which selectively affects motor neurons throughout the central nervous system. The extensive distribution of motor neurons is an obstacle to applying cell transplantation therapy for the treatment of ALS. To overcome this problem, we developed a cell transplantation method via the fourth cerebral ventricle in mice. We used mouse olfactory ensheathing cells (OECs) and rat mesenchymal stem cells (MSCs) as donor cells. OECs are reported to promote regeneration and remyelination in the spinal cord, while MSCs have a capability to differentiate into several types of specific cells including neural cells. Furthermore both types of cells can be relatively easily obtained by biopsy in human. Initially, we confirmed the safety of the operative procedure and broad distribution of grafted cells in the spinal cord using wild-type mice. After transplantation, OECs distributed widely and survived as long as 100 days after transplantation, with a time-dependent depletion of cell number. In ALS model mice, OEC transplantation revealed no adverse effects but no significant differences in clinical evaluation were found between OEC-treated and non-transplanted animals. After MSC transplantation into the ALS model mice, females, but not males, showed a statistically longer disease duration than the non-transplanted controls. We conclude that intrathecal transplantation could be a promising way to deliver donor cells to the central nervous system. Further experiments to elucidate relevant conditions for optimal outcomes are required.

Mouse motor neuron disease caused by truncated SOD1 with or without C-terminal modification.

Mutation of Cu/Zn superoxide dismutase (SOD1) contributes to a portion of the cases of familial amyotrophic lateral sclerosis (FALS). We previously reported on a FALS family whose members had a mutant form of SOD1 characterized by a 2-base pair (bp) deletion at codon 126 of the SOD1 gene. To investigate the cellular consequences of this mutation, we produced transgenic mice that expressed normal and mutated copies of human SOD1: wild-type SOD1 (W), wild-type SOD1 with a FLAG epitope at C-terminal (WF), mutated SOD1 with the 2-bp deletion (D), and SOD1 with the 2-bp deletion with FLAG (DF). The mice heterozygotic for the human mutated SOD1 (D and DF) showed distinct ALS-like motor symptoms, whereas the mice heterozygotic for the normal SOD1 (W and WF) mice did not. Homozygotes of D and DF lines showed the ALS symptoms at an earlier age and died earlier than the heterozygotes. By Northern blot analysis, the mRNAs for all human SOD1s were confirmed in these lines. All the human SOD1 proteins, except the D mutant, were detectable by immunoblot. The D protein was only confirmed when it was concentrated by immunoprecipitation. Neuropathologically, loss of spinal motor neurons and reactive gliosis were common features in the symptomatic lines. The remaining motor neurons in these mice also exhibited eosinophilic inclusions. The biochemical and pathological characteristics of these mice are quite similar to those of human FALS patients with same mutation. This intriguing model will provide an important source of information of the pathogenesis of FALS.