Study of the oncogenic lncRNA ZEB1-AS1 in sporadic ALS : implication for neuronal differentiation and identification of a novel disease pathway

Alterations in the expression levels of RNAs in the pathogenesis of sporadic ALS (sALS) are becoming increasingly relevant, with RNA-seq data highlighting numerous deregulated long non-coding RNAs (lncRNAs) in tissues derived from sALS patients. The oncogenic lncRNA ZEB1-AS1 emerged as strongly downregulated in peripheral blood mononuclear cells (PBMCs) of sALS patients. In cancer-derived cell lines, ZEB1-AS1 has been shown to act in a feedback negative loop with mir200c, acting as a molecular sponge for this miRNA. Furthermore, ZEB1-AS1’s interaction with mir200c results in the upregulation of the downstream molecule BMI1. In PBMCs and spinal cords of sALS patients versus healthy controls we observed a downregulation of ZEB1-AS1’s expression but not of its sense gene ZEB1. We observed an increase of mir200c and a decrease of BMI1, in an opposite pattern to what is observed in cancer, suggesting a possible sALS involved pathway. Furthermore, we observed an upregulation of BMI1’s downstream mediators p53 and GSK3b, both involved in neuronal death in ALS. We created an in vitro model silencing ZEB1-AS1 in SH-SY5Y, both undifferentiated and differentiated. This downregulation does not influence ZEB1’s levels, mimicking what observed in sALS. Concordantly, we found that the investigated pathway presents the same deregulations as in PBMCs of sALS patients. Interestingly, we found that ZEB1 and ZEB1-AS1’s levels change during neuronal differentiation, suggesting an implication for the lncRNA in this process. We demonstrated that ZEB1-AS1 can bind the ALS-implicated RNA binding protein FUS, both in SH-SY5Y cells and in PBMCs, and in this last tissue we found a reduction in the amount of ZEB1-AS1 bound to FUS in sALS patients. In conclusion, our results show an implication for ZEB1-AS1’s pathway in ALS and neuronal differentiation, and we report an interaction of ZEB1-AS1 with FUS, impaired in sALS patients, suggesting the mechanism connecting ZEB1-AS1 to sALS pathology.