The paracaspase MALT1 controls cholesterol homeostasis in glioblastoma stem-like cells through lysosome proteome shaping

• DOI: 10.1016/j.celrep.2023.113631
• Publication Date: 2024-01-05T20:13:54Z
• Authors: Clément Maghe; Kilian Trillet; Gwennan André-Gré...; Mathilde Kerhervé; Laura Merlet; Kathryn A. Jacobs; Kristine Schauer; Nicolas Bidère; Julie Gavard
• Keywords: 0301 basic medicine; Proteome; QH301-705.5; [SDV.NEU.NB] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]/Neurobiology; Intracellular Signaling Peptides and Proteins; Niemann-Pick Disease, Type C; 03 medical and health sciences; Cholesterol; [SDV.CAN] Life Sciences [q-bio]/Cancer; Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein; [SDV.BC.BC] Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC]; CP: Cell biology; [SDV.BBM.GTP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN]; Humans; Homeostasis; Biology (General); Carrier Proteins; Glioblastoma; Lysosomes; CP: Cancer

Glioblastoma stem-like cells (GSCs) compose a tumor-initiating and -propagating population remarkably vulnerable to variation in the stability and integrity of the lysosomal compartment. Previous work has shown that the expression and activity of the paracaspase MALT1 control GSC viability via lysosome abundance. However, the underlying mechanisms remain elusive. By combining RNA sequencing (RNA-seq) with proteome-wide label-free quantification, we now report that MALT1 repression in patient-derived GSCs alters the homeostasis of cholesterol, which accumulates in late endosomes (LEs)-lysosomes. This failure in cholesterol supply culminates in cell death and autophagy defects, which can be partially reverted by providing exogenous membrane-permeable cholesterol to GSCs. From a molecular standpoint, a targeted lysosome proteome analysis unraveled that Niemann-Pick type C (NPC) lysosomal cholesterol transporters are diluted when MALT1 is impaired. Accordingly, we found that NPC1/2 inhibition and silencing partially mirror MALT1 loss-of-function phenotypes. This supports the notion that GSC fitness relies on lysosomal cholesterol homeostasis.