Sensory neuron targeting by self-complementary AAV8 via lumbar puncture for chronic pain

Abstract

Lumbar puncture (LP) is an attractive route to deliver drugs to the nervous system because it is a safe bedside procedure. Its use for gene therapy has been complicated by poor vector performance and failure to target neurons. Here we report highly effective gene transfer to the primary sensory neurons of the dorsal root ganglia (DRGs) with self-complementary recombinant adeno-associated virus serotype 8 (sc-rAAV8) modeling an LP. Transgene expression was selective for these neurons outlining their cell bodies in the DRGs and their axons projecting into the spinal cord. Immunohistochemical studies demonstrated transduction of cells positive for the nociceptive neuron marker vanilloid receptor subtype 1, the small peptidergic neuron markers substance P and calcitonin generelated peptide, and the nonpeptidergic neuron marker griffonia simplicifolia isolectin B4. We tested the efficacy of the approach in a rat model of chronic neuropathic pain. A single administration of sc-rAAV8 expressing the analgesic gene prepro-␤-endorphin (pp␤EP) led to significant (P < 0.0001) reversal of mechanical allodynia for >3 months. The antiallodynic effect could be reversed by the -opioid antagonist naloxone 4 months after gene transfer (P < 0.001). Testing of an alternative nonopioid analgesic gene, IL-10, alone or in combination with pp␤EP was equally effective (P < 0.0001). All aspects of the procedure, such as the use of an atraumatic injection technique, isotonic diluent, a low-infusion pressure, and a small injection volume, are consistent with clinical practice of intrathecal drug use. Therefore, gene transfer by LP may be suitable for developing gene therapy-based treatments for chronic pain.adeno-associated virus ͉ dorsal root ganglion ͉ gene therapy ͉ ␤-endorphin ͉ IL-10

Schwann cell targeting via intrasciatic injection of AAV8 as gene therapy strategy for peripheral nerve regeneration

“…Different serotypes of adeno-associated vectors (AAV) also transduce sensory neurons in the dorsal root ganglia (DRG) through direct administration into the cerebral spinal fluid or via retrograde transport. [3][4][5][6] Specific transduction of non-neuronal cell types in the PNS, particularly of Schwann cells, may be of great interest for the treatment of hypo-or de-myelinating diseases, diabetic neuropathy or to overexpress trophic factors for nerve regeneration. Transduction with first-generation adenovirus showed a broad but transient tropism in many tissues, including different cell types in the PNS.…”

AAV for pain: steps towards clinical translation

“…Our studies showed efficient targeting of primary sensory neurons and transgene expression for up to 4 months; 19,20 follow-up experiments found that transgene expression persisted undiminished for at least 15 months after gene transfer, the longest time point that we tested (unpublished).…”

“…The above discussed study 20 showed highly efficient and selective gene transfer into primary sensory neurons by administration of sc-rAAV8 vectors into the lumbar CSF. Transduction was selective for DRG neurons and did not affect other cells of the CNS.…”

“…Our standard amount of IT administered rAAV was 3 Â 10 9 in our initial study 19 and 3 Â 10 10 subsequently. 20 The higher amount became an option only as we grew to be more practiced with vector production. As we have yet to perform a definitive quantitative comparison, it is our impression that in the rat IT space, 3 Â 10 9 is around the minimum to achieve readily detectable gene expression in dorsal root ganglia (DRGs) and therapeutic efficacy in behavior models (when using self-complementary versions of serotype 1 or 8 vectors).…”

Lentiviral vectors for gene transfer into the spinal cord glial cells

“…This approach would require a direct intraparenchymal injection of vectors rather than intrathecal administration, which tends to the predominant transduction of meningeal cells or DRG sensory neurons and only very modest transduction of spinal cord tissue. [13][14][15] Additionally, central nervous system (CNS) intraparenchymal injection of vector limits the systemic immune response, thus inducing only a negligible inflammatory response. 16 Lentiviral vectors as a potential tool for targeting spinal cord glia Lentiviral (LV) vectors appear to be the best candidates for targeting spinal cord glia.…”