Therapeutic reversal of Huntington’s disease by in vivo self-assembled siRNAs

Abstract

Huntington’s disease is an autosomal-dominant neurodegenerative disease caused by CAG expansion in exon 1 of the huntingtin (HTT) gene. Since mutant huntingtin (mHTT) protein is the root cause of Huntington’s disease, oligonucleotide-based therapeutic approaches using small interfering RNAs (siRNAs) and antisense oligonucleotides designed to specifically silence mHTT may be novel therapeutic strategies for Huntington’s disease. Unfortunately, the lack of an effective in vivo delivery system remains a major obstacle to realizing the full potential of oligonucleotide therapeutics, especially regarding the delivery of oligonucleotides to the cortex and striatum, the most severely affected brain regions in Huntington’s disease. In this study, we present a synthetic biology strategy that integrates the naturally existing exosome-circulating system with artificial genetic circuits for self-assembly and delivery of mHTT-silencing siRNA to the cortex and striatum. We designed a cytomegalovirus promoter-directed genetic circuit encoding both a neuron-targeting rabies virus glycoprotein tag and an mHTT siRNA. After being taken up by mouse livers after intravenous injection, this circuit was able to reprogramme hepatocytes to transcribe and self-assemble mHTT siRNA into rabies virus glycoprotein-tagged exosomes. The mHTT siRNA was further delivered through the exosome-circulating system and guided by a rabies virus glycoprotein tag to the cortex and striatum. Consequently, in three mouse models of Huntington’s disease treated with this circuit, the levels of mHTT protein and toxic aggregates were successfully reduced in the cortex and striatum, therefore ameliorating behavioural deficits and striatal and cortical neuropathologies. Overall, our findings establish a convenient, effective and safe strategy for self-assembly of siRNAs in vivo that may provide a significant therapeutic benefit for Huntington’s disease.

A novel fluorescent probe for the detection of Golgi nitroreductase under hypoxic conditions

“…The reaction mechanism of the probe is shown in Scheme 1. The probe structure has been verified by 1 HNMR, 13 CNM, and HRMS. The experimental data of 1 HNMR and HRMS show that the mechanism by which Gol-NTR recognizes NTR is consistent with our prediction.…”

“…[9][10][11][12] Golgi dysfunction may be closely related to the occurrence of tumors. [13][14][15] An increasing number of studies have shown that the Golgi is the center that drives the survival and migration of cancer cells, so it is also important to monitor NTR in the cellular Golgi. 16 However, in the current field of fluorescent probes, there are few probes targeting the Golgi apparatus.…”

Nucleic acid drug vectors for diagnosis and treatment of brain diseases

“…In 2021, Chen et al proposed a strategy to stimulate host tissue to secrete therapeutic exosomes in vivo. 554 , 569 These exosomes with nucleic acid drugs and ligands directly migrate to the lesion for disease treatment. That is, there is no need to isolate, extract, purify, and modify exosomes and load drugs onto exosomes in vitro.…”

A Novel Perspective on Ischemic Stroke: A Review of Exosome and Noncoding RNA Studies

“…This delivery method induced the downregulation of HMGB1 and decreased levels of tumor necrosis factor-α (TNF-α) and apoptosis, leading to reduced infarct volume [ 52 ]. Moreover, Zhang’s team established a self-assembly strategy of siRNAs in vivo with safety and effectivity and delivered mHTT-silencing siRNA to the cortex and striatum based on a rabies virus glycoprotein-tagged exosome-circulating system, ameliorating behavioral deficits in Huntington’s disease [ 57 ]. Meanwhile, the long-term influence of repeated administration on the liver function and exploration of the half-lives, distribution, and metabolism of exosomal siRNAs are conducive to the assessment of the safety and optimal dosage of exosomal RNAs delivery, which is the foundation of clinical translation [ 58 ].…”