advertisement
Abstract #59004 Published in IGR 16-3
Tumor necrosis factor-alpha mediates activation of NF-κB and JNK signaling cascades in retinal ganglion cells and astrocytes in opposite ways
Dvoriantchikova G; Ivanov DEuropean Journal of Neuroscience 2014; 40: 3171-3178
Tumor necrosis factor-alpha (TNF) is an important mediator of the innate immune response in the retina. TNF can activate various signaling cascades, including NF-κB, nuclear factor kappa B (NF-κB) and c-Jun N-terminal kinase (JNK) pathways. The harmful role of these pathways, as well as of TNF, has previously been shown in several retinal neurodegenerative conditions including glaucoma and retinal ischemia. However, TNF and TNF-regulated signaling cascades are capable not only of mediating neurotoxicity, but of being protective. We performed this study to delineate the beneficial and detrimental effects of TNF signaling in the retina. To this end, we used TNF-treated primary retinal ganglion cell (RGC) and astrocyte cultures. Levels of expression of NF-κB subunits in RGCs and astrocytes were evaluated by quantitative RT-PCR (qRT-PCR) and Western blot (WB) analysis. NF-κB and JNK activity in TNF-treated cells was determined in a time-dependent manner using ELISA and WB. Gene expression in TNF-treated astrocytes was measured by qRT-PCR. We found that NF-κB family members were present in RGCs and astrocytes at the mRNA and protein levels. RGCs failed to activate NF-κB in the presence of TNF, a phenomenon that was associated with sustained JNK activation and RGC death. However, TNF initiated the activation of NF-κB and mediated transient JNK activation in astrocytes. These events were associated with glial survival and increased expression of neurotoxic pro-inflammatory factors. Our findings suggest that, in the presence of TNF, NF-κB and JNK signaling cascades are activated in opposite ways in RGCs and astrocytes. These events can directly and indirectly facilitate RGC death.
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
Full articleClassification:
3.6 Cellular biology (Part of: 3 Laboratory methods)
3.5 Molecular biology incl. SiRNA (Part of: 3 Laboratory methods)
11.8 Neuroprotection (Part of: 11 Medical treatment)
