Biomedical Sciences ETDs

Publication Date

Spring 5-15-2020

Abstract

Anti-inflammatory intrathecal non-viral interleukin-10 (IL-10) gene therapy provides enduring relief of chronic pain in numerous animal pain models. Co-administration of the mannose receptor (MR) ligand D-mannose (DM) improves non-viral IL-10 gene therapeutic efficacy, but questions remain regarding which pain-relevant tissues are critical for non-viral transgene expression resulting in long-lasting pain relief. Additionally, the role of endogenous IL-10 in non-viral IL-10 therapeutic effects is completely unknown.

Chapter I is an Introduction to the studies detailed in this dissertation, providing a historical perspective of the field of neuroinflammation and a framework upon which neuroimmune processes intersect with mechanisms underlying pathological pain. The work presented in Chapter II investigates in vivo the mechanisms that underlie pain relief following intrathecal non-viral IL-10 gene therapy formulated with DM for treatment of peripheral neuropathic pain. Naked plasmid DNA encoding the IL-10 transgene (pDNA-IL-10) was co-injected intrathecally with DM in both IL-10 wildtype (WT) and IL-10 deficient (IL-10 KO) neuropathic mice. We show that DM/pDNA-IL-10 is efficacious in both backgrounds, indicating that endogenous IL-10 is not required for efficacy of DM/pDNA-IL-10 therapy. We next demonstrate the biodistribution of the IL-10 transgene, with key expression in the ipsilateral dorsal root ganglia (DRG) of pain-relieved mice that induces local anti-inflammatory effects. This drives further anti-inflammatory changes at the level of the lumbar spinal cord, which are mirrored by decreased expression of glial activation markers. We further demonstrate that MR activation itself provides transient pain relief in IL-10 KO mice. This supports an IL-10-independent anti-inflammatory mechanism by which MR-mediated actions modulate pain signaling.

The work presented in Chapter III utilizes in vitro primary cell culture techniques to explore the cellular mechanisms by which MR activation mediates IL-10 independent anti-inflammation. This approach is also applied to examine and the cellular conditions (basal vs. inflammatory stimulation) required for DM-mediated transgene adjuvant effects. These preliminary studies indicate that MR activation decreases nitric oxide (NO) production in an IL-10-independent manner. We also present evidence that the timing of inflammation and the relative expression levels of MR dramatically impact the efficacy of MR-mediated anti-inflammatory-like conditions.

Chapter IV discusses pain as a chronic inflammatory disease and explores the versatility of DM/pDNA-IL-10 gene therapy in the treatment of chronic pain of different etiologies. It also indicates that MR activation by DM has utility beyond the realm of non-viral gene therapy and puts forth that MR should be explored as a therapeutic target in its own right for treatment of chronic pain.

Keywords

non-viral gene therapy, interleukin-10, peripheral neuropathic pain, D-mannose, pro-inflammatory cytokines, anti-inflammatory cytokines

Document Type

Dissertation

Language

English

Degree Name

Biomedical Sciences

Level of Degree

Doctoral

Department Name

Biomedical Sciences Graduate Program

First Committee Member (Chair)

Erin D. Milligan

Second Committee Member

C. Fernando Valenzuela

Third Committee Member

Nora Perrone-Bizzozero

Fourth Committee Member

Kiran Bhaskar

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