Rationale and hypothesis: Diabetic neuropathy involves dying back of nerve endings that reflects impairment in axonal plasticity and regenerative nerve growth. Metabolic changes in diabetes can lead to a dysregulation of hormonal mediators, such as cytokines. Thus I studied the effect of interleukin-17A (IL-17A), a proinflammatory cytokine produced by T-cells, on the phenotype of sensory neurons derived from control or diabetic rats. I hypothesized that IL-17A induces neurite outgrowth in sensory neurons through signaling pathways that enhance mitochondrial function. IL-17A can also reverse impaired nerve regeneration associated with diabetes
Objectives: Determine the ability of IL-17A to enhance neurite outgrowth in cultured sensory neurons. Investigate the signalling pathways activated by IL-17A and mechanistically link to neurite outgrowth. Study the ability of IL-17A to improve mitochondrial function of sensory neurons (since axon outgrowth consumes high levels of ATP).
Methodology: Cultured adult dorsal root ganglia (DRG) sensory neurons derived from age matched control or streptozotocin (STZ)-induced type 1 diabetic rats were fixed and stained for fluorescent imaging to determine total neurite outgrowth. Western blotting determined the levels of MAPK and PI-3K activation by IL-17A and for measuring levels of proteins of mitochondrial oxidative phosphorylation pathway. Mitochondrial bioenergetic function was tested in cultured DRG neurons using the Seahorse XF Analyzer.
Results: I found that IL-17A (10 ng/ml; P<0.05) significantly increased total neurite outgrowth in cultures derived from both control and STZ-diabetic rat models. This enhancement was mediated by IL-17A-dependent activation of MAPK and PI-3K pathways with maximal effect at 15 minutes (P<0.05). Pharmacological blockade of one of these activated pathways led to total inhibition of neurite outgrowth. IL-17A improved mitochondrial bioenergetic function of sensory neurons. Bioenergetics function was associated with augmented expression of proteins of mitochondrial oxidative phosphorylation.
Conclusion: IL-17A enhanced axonal plasticity through activation of MAPK and PI-3K pathways and was associated with augmented mitochondrial bioenergetics function in sensory neurons / October 2014
| Identifer | oai:union.ndltd.org:MANITOBA/oai:mspace.lib.umanitoba.ca:1993/23900 |
| Date | 27 August 2014 |
| Creators | Habash, Tarek |
| Contributors | Fernyhough, Paul (Pharmacology and Therapeutics), Albensi, Benedict (Pharmacology and Therapeutics) Czubryt, Michael (Physiology) |
| Source Sets | University of Manitoba Canada |
| Detected Language | English |
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