REN001

A clonal human neural stem cell line (ReN001) has been developed for clinical use in the treatment of stable disability after stroke. This cell line has been conditionally immortalized using the fusion transgene c-mycERTAM to allow controlled expansion when cultured in the presence of 4-hydroxytamoxifen. The cell line has been banked and fully characterized to assure there is genetic stability and no phenotypic drift with extended passages. In vivo studies determined the ability of the cell line to survive after implantation into damaged brain and its efficacy in the reduction of chronic behavioural dysfunction after implantation into a rodent model of stroke damage. A further study was conducted in this model and a dose-dependent effect was observed on behavioural recovery. No safety or toxicology issues were identified in in vivo studies with this cell line, which made REN001 a strong candidate for one of the first cell-based IND applications to be submitted to the Food and Drug Administration in the United States for consideration for the treatment of stroke in humans.

Background: Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an autosomal recessive disease that prevents the body from utilizing long-chain fatty acids for energy, most needed during stress and fasting. Symptoms can appear from infancy through childhood and adolescence or early adulthood, and include hypoglycemia, recurrent rhabdomyolysis, myopathy, hepatopathy, and cardiomyopathy. REN001 is a peroxisome-proliferator-activated receptor delta (PPARδ) agonist that modulates the expression of the genes coding for fatty acid β-oxidation enzymes and proteins involved in oxidative phosphorylation. Here, we assessed the effect of REN001 on VLCAD-deficient patient fibroblasts. Methods: VLCAD-deficient patient and control fibroblasts were treated with REN001. Cells were harvested for gene expression analysis, protein content, VLCAD enzyme activity, cellular bioenergetics, and ATP production. Results: VLCAD-deficient cell lines responded differently to REN001 based on genotype. All cells had statistically significant increases in ACADVL gene expression. Small increases in VLCAD protein and enzyme activity were observed and were cell-line- and dose-dependent. Even with these small increases, cellular bioenergetics improved in all cell lines in the presence of REN001, as demonstrated by the oxygen consumption rate and ATP production. VLCAD-deficient cell lines containing missense mutations responded better to REN001 treatment than one containing a duplication mutation in ACADVL. Discussion: Treating VLCAD-deficient fibroblasts with the REN001 PPARδ agonist results in an increase in VLCAD protein and enzyme activity, and a decrease in cellular stress. These results establish REN001 as a potential therapy for VLCADD as enhanced expression may provide a therapeutic increase in total VLCAD activity, but suggest the need for mutation-specific treatment augmented by other treatment measures.