Diabetes impairs an interleukin-1 beta-dependent pathway that enhances neurite outgrowth through JAK/STAT3 modulation of mitochondrial bioenergetics in adult sensory neurons

作者：Saleh Ali^*; Chowdhury Subir K Roy; Smith Darrell R; Balakrishnan Savitha; Tessler Lori; Schartner Emily; Bilodeau Andre; Van der Ploeg Randy; Fernyhough Paul

来源：Molecular Brain, 2013, 6(1): 45.

DOI：10.1186/1756-6606-6-45

• Neurotrophic factor
• Axon regeneration
• Bioenergetics
• Neuropathy
• Dorsal root ganglia

Background: A luminex-based screen of cytokine expression in dorsal root ganglia (DRG) and nerve of type 1 diabetic rodents revealed interleukin-1 (IL-1 alpha) and IL-1 beta to be significantly depressed. We, therefore, tested the hypothesis that impaired IL-1 alpha and IL-1 beta expression in DRG may contribute to aberrant axon regeneration and plasticity seen in diabetic sensory neuropathy. In addition, we determined if these cytokines could optimize mitochondrial bioenergetics since mitochondrial dysfunction is a key etiological factor in diabetic neuropathy. %26lt;br%26gt;Results: Cytokines IL-1 alpha and IL-1 beta were reduced 2-fold (p%26lt;0.05) in DRG and/or nerve of 2 and 5 month streptozotocin (STZ)-diabetic rats. IL-2 and IL-10 were unchanged. IL-1 alpha and IL-1 beta induced similar 2 to 3-fold increases in neurite outgrowth in cultures derived from control or diabetic rats (p%26lt;0.05). STAT3 phosphorylation on Tyr705 or Ser727 was depressed in DRG from STZ-diabetic mice and treatment of cultures derived from STZ-diabetic rats with IL-1 beta for 30 min raised phosphorylation of STAT3 on Tyr705 and Ser727 by 1.5 to 2-fold (p%26lt;0.05). shRNA-based or AG490 inhibition of STAT3 activity or shRNA blockade of endogenous IL-1 beta expression completely blocked neurite outgrowth. Cultured neurons derived from STZ-diabetic mice were treated for 24 hr with IL-1 beta and maximal oxygen consumption rate and spare respiratory capacity, both key measures of bioenergetic fidelity that were depressed in diabetic compared with control neurons, were enhanced 2-fold. This effect was blocked by AG490. %26lt;br%26gt;Conclusions: Endogenous synthesis of IL-1 beta is diminished in nerve tissue in type 1 diabetes and we propose this defect triggers reduced STAT3 signaling and mitochondrial function leading to sup-optimal axonal regeneration and plasticity.

• 出版日期2013-10-24