We have developed a highly effective method for in vivo gene silencing in the spinal cord and dorsal root ganglia (DRG) by a cationic lipid facilitated delivery of synthetic, small interfering RNA (siRNA). A siRNA to the delta opioid receptor (DOR), or a mismatch RNA, was mixed with the transfection reagent, i-Fect™ (vehicle), and delivered as repeated daily bolus doses (0.5 μg to 4 μg) via implanted intrathecal catheter to the lumbar spinal cord of rats. Twenty-four hours after the last injection, rats were tested for antinociception by the DOR selective agonist, [D-Ala2, Glu4]deltorphin II (DELT), or the mu opioid receptor (MOR) selective agonist, [D-Ala2, N-Me-Phe4, Gly-ol5]enkephalin (DAMGO). Pretreatment with the siRNA, but not the mismatch RNA or vehicle alone, blocked DELT antinociception dose-dependently. The latter was concomitant with a reduction in the spinal immunoreactivity and receptor density of DOR, and in DOR transcripts in the lumbar DRG and spinal dorsal horn. Neither siRNA nor mismatch RNA pretreatment altered spinal immunoreactivity of MOR or antinociception by spinal DAMGO, and had no effect on the baseline thermal nociceptive threshold. The inhibition of function and expression of DOR by siRNA was reversed by 72 hr after the last RNA injection. The uptake of fluorescence-tagged siRNA was detected in both DRG and spinal cord. The low effective dose of siRNA/i-Fect™ complex reflects an efficient delivery of the siRNA to peripheral and spinal neurons, produced no behavioral signs of toxicity. This delivery method may be optimized for other gene targets.
An efficient intrathecal delivery of small interfering RNA to the spinal cord and peripheral neurons
Miaw-chyi Luo,Dongqin Zhang,Shou-wu Ma,Yuan-yuan Huang,S. Shuster,F. Porreca,J. Lai
Published 2005 in Molecular Pain
ABSTRACT
PUBLICATION RECORD
- Publication year
2005
- Venue
Molecular Pain
- Publication date
2005-01-01
- Fields of study
Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
CITATION MAP
EXTRACTION MAP
CLAIMS
CONCEPTS
- damgo
[D-Ala2, N-Me-Phe4, Gly-ol5]enkephalin, a mu opioid receptor-selective agonist used as a functional control.
Aliases: [D-Ala2, N-Me-Phe4, Gly-ol5]enkephalin
- delt
[D-Ala2, Glu4]deltorphin II, a delta opioid receptor-selective agonist used to test antinociception.
Aliases: [D-Ala2, Glu4]deltorphin II, deltorphin II
- delta opioid receptor
The opioid receptor targeted by the siRNA and assessed through DOR expression and DELT responses.
Aliases: DOR
- dorsal root ganglia
Peripheral sensory ganglia sampled for DOR transcript changes and siRNA uptake.
Aliases: DRG
- intrathecal catheter delivery
A lumbar intrathecal catheter-based route used to administer repeated bolus RNA doses to the spinal cord.
Aliases: intrathecal administration, lumbar intrathecal catheter
- mismatch rna
A control RNA with a mismatched sequence used to compare against the DOR-specific siRNA.
Aliases: mismatch siRNA, control RNA
- sirna/i-fect complex
A cationic lipid transfection mixture formed by combining synthetic siRNA with the i-Fect reagent for in vivo delivery.
Aliases: i-Fect complex, siRNA/i-Fect
- spinal cord
The lumbar central nervous system tissue targeted by intrathecal dosing and examined for receptor and transcript changes.
Aliases: lumbar spinal cord, spinal dorsal horn
REFERENCES
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