High-capacity adenoviral vector-mediated reduction of huntingtin aggregate load in vitro and in vivo

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Huntington's disease (HD) is a neurodegenerative disorder caused by CAG repeat expansion in the huntingtin (HTT) gene.
• Mutant Huntingtin protein (Htt) expression is crucial for HD pathogenesis.
• Targeting mutant Htt expression is a potential therapeutic strategy for HD.

Purpose of the Study:

• To develop and evaluate a gene therapy approach using short hairpin RNA (shRNA) delivered via a high-capacity adenoviral (HC-Ad) vector to inhibit mutant Htt expression.
• To assess the efficacy of this vector in reducing Htt aggregation in vitro and in vivo.

Main Methods:

• Generation of an HC-Ad vector expressing shRNA targeting the HTT gene.
• In vitro assessment of Htt expression inhibition and aggregate reduction in neuronal and nonneuronal cell lines.
• In vivo evaluation in two mouse models of HD (R6/2 and adenoviral vector-induced) using stereotaxic injection into the striatum.
• Quantification of Htt-immunoreactive (IR) aggregates to measure therapeutic effect.

Main Results:

• The HC-Ad vector demonstrated efficient inhibition of Htt expression in vitro.
• Significant reduction in Htt-IR aggregates was observed in vitro after gene transfer.
• In vivo studies in both HD mouse models showed a marked decrease in mutant Htt aggregate load.
• The shRNA-mediated reduction of aggregate formation was confirmed in vivo.

Conclusions:

• The developed HC-Ad vector effectively reduces mutant Htt expression and aggregation.
• This shRNA-based gene therapy approach shows significant therapeutic potential for Huntington's disease.
• Further development of this strategy is warranted for clinical application in HD treatment.