Dysfunctional astrocytes take part in oligodendroglial pathology in Autosomal Dominant Leukodystrophy

Autosomal Dominant LeukoDystrophy (ADLD) is an adult-onset demyelinating disease due to Lamin B1 (LMNB1) duplication. Although the genetic cause of ADLD has been well-established, the underlying pathological mechanisms driving the onset and the progression of disease remain poorly understood. Oligodendrocytes (OLs), the myelin-producing cells of the central nervous system, have been the primary focus in ADLD research as they are the most obviously affected cell type in ADLD. However, recent evidence has shifted the attention to the potential role of astrocytes in ADLD pathogenesis. This study focuses on the role of astrocytes in oligodendroglia pathology using astrocytes differentiated from patient-derived human-induced pluripotent stem cells (hiPSC). We investigated whether astrocytes obtained from ADLD patients exerted pathological actions on OLs through two complementary in vitro experimental approaches: i) we assessed the impact of the conditioned medium (ACM) obtained from ADLD or CTRL hAstrocytes on the survival and differentiation of healthy murine OLs; ii) we assessed the impact of transplant of ADLD or CTRL hAstrocytes on remyelination in organotypic cerebellar slices. These methods enabled modelling some aspects of the interplay between astrocytes and OLs in both healthy and diseased states. Additionally, in these experiments we also tested the efficacy of shRNA-mediated silencing of one LMNB1 allele reverting the diseased astrocytes’ effects. Our findings show a marked reduction in oligodendroglia survival and differentiation when cells were cultured with the ACM derived from ADLD hAstrocytes, and an impaired re-myelination of the cerebellar slices transplanted with ADLD hAstrocytes, after lysolecithin treatment. These alterations were improved when OLs were cultured with ACM from ADLD shRNA-corrected hAstrocytes, and when slices were transplanted with ADLD shRNA-corrected hAstrocytes. Overall, our results suggest a role for astrocytic dysfunctions in ADLD pathogenesis and highlight the importance of further investigating therapeutic strategies targeting not only OLs but also other cell types, especially astrocytes.