ABSTRACT
Abnormal expansion of a polyglutamine tract in huntingtin (Htt) protein results in Huntington's disease (HD), an autosomal dominant neurodegenerative disorder involving progressive loss of motor and cognitive function. Contrasting with the ubiquitous tissue expression of polyglutamine-expanded Htt, HD pathology is characterized by the increased vulnerability of specific neuronal populations within the striatum and the cerebral cortex. Morphological, biochemical, and functional characteristics of neurons affected in HD that might render these cells more vulnerable to the toxic effects of polyglutamine-Htt are covered in this review. The differential vulnerability of neurons observed in HD is discussed in the context of various major pathogenic mechanisms proposed to date, and in line with evidence showing a 'dying-back' pattern of degeneration in affected neuronal populations.
Subject(s)
Huntington Disease/pathology , Neurons/pathology , Axonal Transport/physiology , Brain/pathology , Brain Chemistry/physiology , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/physiology , Gene Expression/genetics , Gene Expression/physiology , Humans , Huntingtin Protein , Huntington Disease/etiology , Huntington Disease/genetics , Mitochondria/pathology , Mutation/physiology , Nerve Degeneration/pathology , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/toxicity , Neurons/classification , Nuclear Proteins/genetics , Nuclear Proteins/toxicity , Signal TransductionABSTRACT
Members of the GDNF family of ligands, including neurturin (NTN), have been implicated as potential therapeutic agents for Huntington's disease (HD). The present study examined the ability of CERE-120 (AAV2-NTN) to provide structural and functional protection in the N171-82Q transgenic HD mouse model. AAV2-NTN therapy attenuated rotorod deficits in this mutant relative to control treated transgenics (p<0.01). AAV2-NTN treatment significantly reduced the number of transgenic mice that exhibited clasping behavior and partially restored their stride lengths (both p<0.05). Stereological counts of NeuN-ir neurons revealed a significant neuroprotection in the striatum of AAV2-NTN treated relative to control treated transgenics (p<0.001). Most fascinating, stereological counts of NeuN-labeled cells in layers V-VI of prefrontal cortex revealed that intrastriatal AAV2-NTN administration prevented the loss of frontal cortical NeuN-ir neurons seen in transgenic mice (p<0.01). These data indicate that gene delivery of NTN may be a viable strategy for the treatment of this incurable disease.
Subject(s)
Cerebral Cortex/physiopathology , Corpus Striatum/physiopathology , Genetic Therapy , Huntington Disease/therapy , Motor Activity , Neurons/physiology , Neurturin/genetics , Animals , DNA-Binding Proteins , Dependovirus/genetics , Disease Models, Animal , Gene Expression , Gene Transfer Techniques , Genetic Vectors , Huntingtin Protein , Huntington Disease/genetics , Huntington Disease/physiopathology , Mice , Mice, Transgenic , Mutation , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Neurturin/metabolism , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Random Allocation , Rotarod Performance TestABSTRACT
The recent development of HIV-1 lentiviral vectors is especially useful for gene transfer because they achieve efficient integration into nondividing cell genomes and successful long-term expression of the transgene. These attributes make the vector useful for gene delivery, mutagenesis, and other applications in mammalian systems. Here we describe two HIV-1-based lentiviral vector derivatives, pZR-1 and pZR-2, that can be used in gene-trap experiments in mammalian cells in vitro and in vivo. Each lentiviral gene-trap vector contains a reporter gene, either beta-lactamase or enhanced green fluorescent protein (EGFP), that is inserted into the U3 region of the 3' long terminal repeat. Both of the trap vectors readily integrate into the host genome by using a convenient infection technique. Appropriate insertion of the vector into genes causes EGFP or beta-lactamase expression. This technique should facilitate the rapid enrichment and cloning of the trapped cells and provides an opportunity to select subpopulations of trapped cells based on the subcellular localization of reporter genes. Our findings suggest that the reporter gene is driven by an upstream, cell-specific promoter during cell culture and cell differentiation, which further supports the usefulness of lentivirus-based gene-trap vectors. Lentiviral gene-trap vectors appear to offer a wealth of possibilities for the study of cell differentiation and lineage commitment, as well as for the discovery of new genes.
