RESUMO
INTRODUCTION: Tuberous sclerosis complex (TSC) is a genetic disease resulting from mutation in TSC1 or TSC2 and subsequent hyperactivation of mammalian Target of Rapamycin (mTOR). Common TSC features include brain lesions, such as cortical tubers and subependymal giant cell astrocytomas (SEGAs). However, the current treatment with mTOR inhibitors has critical limitations. We aimed to identify new targets for TSC pharmacotherapy. RESULTS: The results of our shRNA screen point to glutamate-cysteine ligase catalytic subunit (GCLC), a key enzyme in glutathione synthesis, as a contributor to TSC-related phenotype. GCLC inhibition increased cellular stress and reduced mTOR hyperactivity in TSC2-depleted neurons and SEGA-derived cells. Moreover, patients' brain tubers showed elevated GCLC and stress markers expression. Finally, GCLC inhibition led to growth arrest and death of SEGA-derived cells. CONCLUSIONS: We describe GCLC as a part of redox adaptation in TSC, needed for overgrowth and survival of mutant cells, and provide a potential novel target for SEGA treatment.
Assuntos
Encéfalo/patologia , Glutamato-Cisteína Ligase/metabolismo , Neurônios/metabolismo , Esclerose Tuberosa/patologia , Adolescente , Animais , Butionina Sulfoximina/farmacologia , Células COS , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Criança , Chlorocebus aethiops , Inibidores Enzimáticos/farmacologia , Feminino , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Imunossupressores/farmacologia , Masculino , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA Interferente Pequeno/farmacologia , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Proteína 1 do Complexo Esclerose Tuberosa , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Adulto JovemRESUMO
Dendritic arbors are compartments of neurons dedicated to receiving synaptic inputs. Their shape is an outcome of both the intrinsic genetic program and environmental signals. The microtubules and actin cytoskeleton are both crucial for proper dendritic morphology, but how they interact is unclear. The present study demonstrates that microtubule plus-end tracking protein CLIP-170 and actin-binding protein IQGAP1 regulate dendrite morphology of rat neurons by coordinating the interaction between microtubules and the actin cytoskeleton. Moreover, we show that mTOR kinase interacts with CLIP-170 and is needed for efficient formation of a protein complex containing CLIP-170 and IQGAP1. Dynamic microtubules, CLIP-170, and IQGAP1 are required for proper dendritic arbor morphology and PI3K-mTOR-induced increase in dendritic arbor complexity. Moreover, CLIP-170 and IQGAP1 knockdown modulates dendritic arbor growth via regulation of the actin cytoskeleton. We postulate that mTOR controls dendritic arbor morphology by enhancing cross talk between dynamic microtubules and actin through CLIP-170 and IQGAP1.
