Confirmation of Decreased Rates of Cerebral Protein Synthesis In Vivo in a Mouse Model of Tuberous Sclerosis Complex

• Published in: eNeuro Vol. 9; no. 4; p. ENEURO.0480-21.2022
• Main Authors: Saré, Rachel Michelle, Torossian, Anita, Loutaev, Inna, Smith, Carolyn Beebe
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 18.07.2022
• Subjects: Confirmation; mTOR; tuberous sclerosis; protein synthesis
• ISSN: 2373-2822; 2373-2822
• DOI: 10.1523/ENEURO.0480-21.2022

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that results in intellectual disability and, in ∼50% of patients, autism spectrum disorder. The protein products that are altered in TSC (TSC1 and TSC2) form a complex to inhibit the mammalian target of rapamycin [mTOR; mTOR complex 1 (mTORC1)] pathway. This pathway has been shown to affect the process of mRNA translation through its action on ribosomal protein S6 and 4-elongation binding protein 1. It is thought that mutations in the TSC proteins lead to upregulation of the mTORC1 pathway and consequently an increase in protein synthesis. Unexpectedly, our previous study of a mouse model of TSC ( ) demonstrated decreased rates of protein synthesis throughout the brain. In the present study, we confirm those results in another +/- mouse model, one with a different mutation locus and on a mixed background ( +/-). We also examine mTORC1 signaling and possible effects of prior isoflurane anesthesia. Because measurements of protein synthesis rates require surgical preparation of the animal and anesthesia, we examine mTORC1 signaling pathways both under baseline conditions and following recovery from anesthesia. Our results demonstrate regionally selective effects of prior anesthesia. Overall, our results in both models suggest differences to the central hypothesis regarding TSC and show the importance of studying protein synthesis Protein synthesis is an important process for brain function. In the disorder, tuberous sclerosis complex (TSC), the inhibition of the mammalian target of rapamycin (mTOR) pathway is reduced and this is thought to lead to excessive protein synthesis. Most studies of protein synthesis in models of TSC have been conducted We report here confirmation of our previous study showing decreased brain protein synthesis rates in a second mouse model of TSC, results counter to the central hypothesis regarding TSC. We also explore the possible influence of prior isoflurane exposure on signaling pathways involved in regulation of protein synthesis. This study highlights a novel aspect of TSC and the importance of studying cellular processes .