Regulated, electroporation-mediated delivery of pro-opiomelanocortin gene suppresses chronic constriction injury-induced neuropathic pain in rats

Abstract

We previously reported that intrathecal pro-opiomelanocortin gene electroporation could reduce pain sensitivity induced by chronic constriction injury (CCI) of the sciatic nerve. For optimal use of antinociceptive gene therapy, it might be important to control the expression of the transfected gene extrinsically. For this purpose, a doxycyclinecontrolled transrepressor system composed of two plasmids coding, respectively, for pro-opiomelanocortin gene (pTRE2-POMC) and the silencer (pTel-off) was employed. The regulation of beta-endorphin expression was first assessed in spinal neuronal culture, then we electrotranfected this plasmid into the spinal cord of mononeuropathic rats and evaluated the analgesic potential of this therapy in vivo by thermal and mechanical withdrawal latency. Intraperitoneal injections of various doses of doxycycline were made to elucidate the possible exogenous downregulation of transfected beta-endorphin gene expression in vivo. The levels of beta-endorphin were analyzed by intrathecal microdialysis and radioimmunoassay. Intrathecal pTRE2-POMC/pTel-off electroporation elevated spinal betaendorphin levels, as manifested in a significantly elevated pain threshold for chronic constriction injury limbs. Intraperitoneal doxycycline decreased the antinociceptive effect and spinal beta-endorphin levels in a dose-dependent manner. We concluded that intrathecal pTRE2-POMC/ pTel-off electroporation alleviates CCI-induced limb pain, and can be controlled by intraperitoneal doxycycline administration.

Distinct roles of exogenous opioid agonists and endogenous opioid peptides in the peripheral control of neuropathy-triggered heat pain

“…48). More recently, spinal delivery of vectors encoding POMC or PENK improved both mechanical and heat hypersensitivity following CCI4950; yet, it is unclear whether actions of such genetically delivered and native opioid peptides are mechanistically identical. Together, the relative contribution of the CNS endogenous opioids to mechanical vs. heat hypersensitivity in neuropathic conditions has not been systematically examined.…”

BAMBI (Bone Morphogenetic Protein and Activin Membrane-Bound Inhibitor) Reveals the Involvement of the Transforming Growth Factor-β Family in Pain Modulation

“…Furthermore, POMC and PENK gene delivery to spinal cord dorsal horn induces analgesia, which is associated with increased production of ␤-endorphin or enkephalin by specific subsets of spinal neurons (Hao et al, 2003;Wu et al, 2004). In addition, it has been demonstrated that mice deficient in PENK showed exaggerated behavioral responses to painful stimuli (König et al, 1996).…”

Electroporation and ultrasound enhanced non-viral gene delivery in vitro and in vivo

“…In vivo electroporation has been shown to be effective for a wide range of tissues, including tumours (Rols et al 1998;Li 2008), skin (Marti et al 2004;Medi and Singh 2008), liver (Jaichandran et al 2006;Kamimura and Liu 2008), lung (Dean et al 2003;Zhou et al 2007), kidney (Franquesa et al 2005), thymus (Irla et al 2008), bladder (Yoshida et al 2008), adipose tissue (Granneman 2008), vasculature (Matsumoto et al 2001), retina (Matsuda and Cepko 2008), cornea (Blair-Parks et al 2002;Oshima et al 2002), ciliary muscle (Bloquel et al 2006), brain (Boutin et al 2008), spinal cord (Wu et al 2004;Chen et al 2008), skeletal muscle (McMahon and Wells 2004;Miyazaki and Miyazaki 2008;Brown et al 2008) and testis (Parrington et al 2007;Dhup andMajumdar 2008, Yomgogida 2008). A range of genetic material has been used: DNA, RNA and oligonucleotides (e.g.…”