Stochastic Model of Tsc1 Lesions in Mouse Brain

Shilpa Prabhakar,Miguel Sena-Esteves,Anat Stemmer-Rachamimov,Roderick Bronson,Xandra O Breakefield,Xuan Zuang,David J Kwiatkowski,Davide Gianni,John W Chen,June Goto,Gregory R Wojtkiewicz,Jillian Brockmann,Jianming Qiu

doi:10.1371/journal.pone.0064224

Abstract

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder due to mutations in either TSC1 or TSC2 that affects many organs with hamartomas and tumors. TSC-associated brain lesions include subependymal nodules, subependymal giant cell astrocytomas and tubers. Neurologic manifestations in TSC comprise a high frequency of mental retardation and developmental disorders including autism, as well as epilepsy. Here, we describe a new mouse model of TSC brain lesions in which complete loss of Tsc1 is achieved in multiple brain cell types in a stochastic pattern. Injection of an adeno-associated virus vector encoding Cre recombinase into the cerebral ventricles of mice homozygous for a Tsc1 conditional allele on the day of birth led to reduced survival, and pathologic findings of enlarged neurons, cortical heterotopias, subependymal nodules, and hydrocephalus. The severity of clinical and pathologic findings as well as survival was shown to be dependent upon the dose and serotype of Cre virus injected. Although several other models of TSC brain disease exist, this model is unique in that the pathology reflects a variety of TSC-associated lesions involving different numbers and types of cells. This model provides a valuable and unique addition for therapeutic assessment.

Highlights

Tuberous sclerosis complex (TSC) is a genetic disorder affecting about 1 in 6,000 newborns caused by inactivating mutations in Tsc1or Tsc2, encoding hamartin and tuberin, respectively [1,2]
AAVrh8-controlled by a hybrid promoter (CBA)-Cre Injections into Tsc1c/c Mice We initially evaluated the survival of Tsc1c/c mice receiving an intracerebral ventricular (ICV) injection of AAVrh8-CBA-Crevectorat P0 (261010 g.c. per 2 ml into each ventricle)
green fluorescent protein (GFP) immunostaining of brains of AAVrh8-CBA-GFP injected mice and non-injected mice at 110 days showed GFP positive cells of different morphologies throughout the perivenmice and non-injected mice (a–c) Cells were larger in AAVrh8-CBA-Cre injected mice than in controls and stained more strongly for pS6

Summary

Introduction

Tuberous sclerosis complex (TSC) is a genetic disorder affecting about 1 in 6,000 newborns caused by inactivating mutations in Tsc1or Tsc, encoding hamartin and tuberin, respectively [1,2]. Biallelic loss of either gene leads to chronic hyperactivation of mTOR complex 1 (mTORC1), and this appears to be the primary pathogenetic mechanism that leads to development of TSC hamartomas in brain, kidney, skin, heart and lung [3,4]. Focal brain pathologies, including cortical tubers and subependymal nodules (SENs), are seen in the majority (.90%) of TSC patients, and have been detected as early as late fetal gestation [5]. Most TSC patients develop multiple neurological manifestations including seizures, intellectual deficit, neurobehavioral syndromes including autism and autism spectrum disorder, and sleep disorders [3]. Five to 10% of SENs show progressive enlargement, are called subependymal giant cell astrocytomas (SEGAs), and can lead to devastating neurologic consequences due to blockage of cerebrospinal fluid (CSF) flow and progressive hydrocephalus

Objectives

Methods

Results

Conclusion