Release of plasmid DNA-encoding IL-10 from PLGA microparticles facilitates long-term reversal of neuropathic pain following a single intrathecal administration.
OBJECTIVE
Interleukin-10 (IL-10) is an anti-inflammatory molecule that has achieved interest as a therapeutic for neuropathic pain. In this work, the potential of plasmid DNA-encoding IL-10 (pDNA-IL-10) slowly released from biodegradable microparticles to provide long-term pain relief in an animal model of neuropathic pain was investigated.


METHODS
PLGA microparticles encapsulating pDNA-IL-10 were developed and assessed both in vitro and in vivo.


RESULTS
In vitro, pDNA containing microparticles activated macrophages, enhanced the production of nitric oxide, and increased the production of IL-10 protein relative to levels achieved with unencapsulated pDNA-IL-10. In vivo, intrathecally administered microparticles embedded in meningeal tissue, induced phagocytic cell recruitment to the cerebrospinal fluid, and relieved neuropathic pain for greater than 74 days following a single intrathecal administration, a feat not achieved with unencapsulated pDNA. Therapeutic effects of microparticle-delivered pDNA-IL-10 were blocked in the presence of IL-10-neutralizing antibody, and elevated levels of plasmid-derived IL-10 were detected in tissues for a prolonged time period post-injection (>28 days), demonstrating that therapeutic effects are dependent on IL-10 protein production.


CONCLUSIONS
These studies demonstrate that microparticle encapsulation significantly enhances the potency of intrathecally administered pDNA, which may be extended to treat other disorders that require intrathecal gene therapy.
Department of Chemical & Biological Engineering, University of Colorado at Boulder, 424 UCB, Boulder, Colorado, 80309, USA.
Ryan Gene
RG
Soderquist
Evan M
EM
Sloane
Lisa C
LC
Loram
Jacqueline A
JA
Harrison
Ellen C
EC
Dengler
Scott M
SM
Johnson
Luke D
LD
Amer
Courtney S
CS
Young
Makenzie T
MT
Lewis
Stephen
S
Poole
Matthew G
MG
Frank
Linda R
LR
Watkins
Erin D
ED
Milligan
Melissa J
MJ
Mahoney
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002478:Cells, Cultured; D004247:DNA / Q000008:administration & dosage* / Q000235:genetics*; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D007150:Immunohistochemistry; D007278:Injections, Spinal; D016753:Interleukin-10 / Q000096:biosynthesis / Q000235:genetics*; D019344:Lactic Acid; D008264:Macrophages / Q000378:metabolism; D008297:Male; D053758:Nanoparticles; D009569:Nitric Oxide / Q000378:metabolism; D010316:Particle Size; D010523:Peripheral Nervous System Diseases / Q000134:cerebrospinal fluid / Q000628:therapy*; D010957:Plasmids / Q000235:genetics*; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016753:Interleukin-10; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D009569:Nitric Oxide; D019344:Lactic Acid; D004247:DNA