Development of 3D human cell culture models for studying MLC disease

Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare disease characterized by macrocephaly, brain edema, cysts, myelin vacuolation, and astrocyte swelling leading to severe motor and cognitive disabilities. In the majority of patients, MLC is caused by mutations in the MLC1 gene, encoding for the MLC1 protein which is primarily expressed at perivascular astrocyte end-feet and astrocytes-astrocyte contacts. The role of MLC1 and the pathological mechanism underlining MLC disease are still unknown, but experimental and clinical evidence suggests that MLC1 could be involved in the control of astrocyte activation and volume regulation following different pathological stimuli. Abnormally activated/swollen astrocytes might be the cause of the brain defects observed in MLC. Hence, MLC is a leukodystrophy caused mainly by astrocyte dysfunctions. The astrocytes perform several important functions during neurodevelopment, they control neurogenesis/synaptogenesis, oligodendrocyte differentiation, myelination, and blood-brain formation. In this study, 3D human cell culture models were generated from human induced pluripotent stem cells derived from healthy individuals and MLC patients carrying mutations in the MLC1 gene to study the effects of MLC1 mutations on neurodevelopment.