Abdelkrim Mannioui1, Quentin Vauzanges2, Jean Baptiste Fini3, Esther Henriet2, Somya Sekizar2, Loris Azoyan2, Jean Léon Thomas4, David Du Pasquier5, Carine Giovannangeli6, Barbara Demeneix3, Catherine Lubetzki2, Bernard Zalc2. 1. Sorbonne Universités UPMC Univ Paris 06, Inserm, CNRS, ICM-GH Pitié-Salpêtrière, and IBPS F-75013 Paris, France. 2. Sorbonne Universités UPMC Univ Paris 06, Inserm, CNRS, APHP, Institut du Cerveau et de la Moelle épinière (ICM), GH Pitié-Salpêtrière, Paris, France. 3. CNRS UMR 7221, Muséum National d'Histoire Naturelle, Paris, France. 4. Sorbonne Universités UPMC Univ Paris 06, Inserm, CNRS, APHP, ICM-GH Pitié-Salpêtrière, Paris, France; Department of Neurology, School of Medicine, Yale University, New Haven, CT, USA. 5. Watchfrog, Evry, France. 6. CNRS UMR 7196, Muséum National d'Histoire Naturelle, Paris, France.
Abstract
BACKGROUND: In multiple sclerosis, development of screening tools for remyelination-promoting molecules is timely. OBJECTIVE: A Xenopus transgenic line allowing conditional ablation of myelinating oligodendrocytes has been adapted for in vivo screening of remyelination-favoring molecules. METHODS: In this transgenic, the green fluorescent protein reporter is fused to E. coli nitroreductase and expressed specifically in myelinating oligodendrocytes. Nitroreductase converts the innocuous pro-drug metronidazole to a cytotoxin. Spontaneous remyelination occurs after metronidazole-induced demyelinating responses. As tadpoles are transparent, these events can be monitored in vivo and quantified. At the end of metronidazole-induced demyelination, tadpoles were screened in water containing the compounds tested. After 72 h, remyelination was assayed by counting numbers of oligodendrocytes per optic nerve. RESULTS: Among a battery of molecules tested, siponimod, a dual agonist of sphingosine-1-phosphate receptor 1 and 5, was among the most efficient favoring remyelination. Crispr/cas9 gene editing showed that the promyelinating effect of siponimod involves the sphingosine-1-phosphate receptor 5. CONCLUSION: This Xenopus transgenic line constitutes a simple in vivo screening platform for myelin repair therapeutics. We validated several known promyelinating compounds and demonstrated that the strong remyelinating efficacy of siponimod implicates the sphingosine-1-phosphate receptor 5.
BACKGROUND: In multiple sclerosis, development of screening tools for remyelination-promoting molecules is timely. OBJECTIVE: A Xenopus transgenic line allowing conditional ablation of myelinating oligodendrocytes has been adapted for in vivo screening of remyelination-favoring molecules. METHODS: In this transgenic, the green fluorescent protein reporter is fused to E. coli nitroreductase and expressed specifically in myelinating oligodendrocytes. Nitroreductase converts the innocuous pro-drug metronidazole to a cytotoxin. Spontaneous remyelination occurs after metronidazole-induced demyelinating responses. As tadpoles are transparent, these events can be monitored in vivo and quantified. At the end of metronidazole-induced demyelination, tadpoles were screened in water containing the compounds tested. After 72 h, remyelination was assayed by counting numbers of oligodendrocytes per optic nerve. RESULTS: Among a battery of molecules tested, siponimod, a dual agonist of sphingosine-1-phosphate receptor 1 and 5, was among the most efficient favoring remyelination. Crispr/cas9 gene editing showed that the promyelinating effect of siponimod involves the sphingosine-1-phosphate receptor 5. CONCLUSION: This Xenopus transgenic line constitutes a simple in vivo screening platform for myelin repair therapeutics. We validated several known promyelinating compounds and demonstrated that the strong remyelinating efficacy of siponimod implicates the sphingosine-1-phosphate receptor 5.