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Rapamycin-insensitive up-regulation of MMP2 and other genes in TSC2- deficient LAM-like cells

ABSTRACT: Rationale: Increased matrix metalloproteinase (MMP) activity has been implicated in the pathogenesis of lymphangioleiomyomatosis (LAM). Objectives: To investigate how TSC1 or TSC2 deficiency alters MMP expression and regulation. Methods: We studied immortalized cells that lack TSC2 derived from an angiomyolipoma (AML) of a LAM patient, and a TSC2 add back derivative; and murine embryonic fibroblast cells that lack Tsc1 or Tsc2 and respective controls. Global gene expression analysis was carried out in the AML and derivative cell lines. MMP levels in the conditioned media from these cells were analyzed by zymography and ELISA. Measurements and Main Results: We found increased MMP-2 expression in cells lacking TSC1/TSC2 compared to their respective controls by zymography. MMP-2 overproduction by these cells was not affected by rapamycin treatment. Gene expression analysis confirmed increased MMP-2 gene expression that was not affected by rapamycin. Furthermore, multiple other genes were found to be over-expressed in rapamycin-treated TSC2-deficient cells compared to TSC2+ cells. Conclusions: We conclude that TSC1/TSC2 deficiency leads to MMP-2 overproduction that is rapamycin insensitive, and that several genes exhibit similar patterns suggesting TSC1/TSC2 dependent but mTOR independent pathways may be involved in the pathogenesis of LAM.

ORGANISM(S): Homo sapiens

PROVIDER: GSE16944 | GEO | 2009/10/21

SECONDARY ACCESSION(S): PRJNA117303

REPOSITORIES: GEO

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Project description:Tuberous sclerosis complex (TSC) is an inherited multi-system disorder caused by mutations in the TSC1 or TSC2 gene. TSC patients are often diagnosed with a range of neurodevelopmental (ND) manifestations termed TSC-associated neuropsychiatric disorders (TAND) including autism spectrum disorder (ASD), intellectual disability (ID), anxiety and mood disorders. Hamartin (TSC1) and tuberin (TSC2) proteins form a complex inhibiting mechanistic target of rapamycin complex 1 (mTORC1) kinase signaling. Loss of TSC1 or TSC2 activates mTORC1 that, among several targets, controls protein synthesis by inhibiting translational repressor eIF4E-binding proteins. Using neural progenitor cells (NPCs) from patient-derived induced pluripotent stem cells (iPSCs), we recently reported early ND phenotypic changes, including increased cell proliferation and altered neurite outgrowth in CRISPR-modified TSC1-null NPCs, which were unaffected by mTORC1 inhibition by rapamycin,the only approved therapy for TSC1. Here, to assess TSC1-dependent gene expression programs in NPCs, we used polysome-profiling, which quantifies changes in mRNA abundance and translational efficiencies at a transcriptome-wide level. In addition to changes in mRNA abundance, this revealed numerous TSC1-dependent alterations in translational efficiencies. To assess the relevance of these gene expression alterations we performed polysome-profiling in post-mortem brains originating from ASD donors and matched controls. Strikingly, TSC1-dependent alterations in mRNA translation observed in NPCs were largely recapitulated in human brains. Furthermore, although polysome-profiling revealed a partial reversal of TSC1-associated gene expression alterations following rapamycin treatment, most genes related to neural activity/synaptic regulation or ASD that showed TSC1-dependent translation were rapamycin-insensitive. Therefore, we also examined whether early ND rapamycin-insensitive phenotypes in TSC1-null NPCs could be rescued by a third-generation bi-steric, mTORC1-selective inhibitor RMC-6272 (Revolution Medicines, Inc.). Unlike rapamycin, RMC-6272 strongly inhibited translation and reversed TSC1-associated proliferation and neurite outgrowth phenotypes. In summary, we reveal ample translational alterations in TSC1 patient-derived NPCs recapitulating human brain expression profiles and potential implications for treatment of TAND.

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Rapamycin-insensitive up-regulation of MMP2 and other genes in TSC2- deficient LAM-like cells

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