Tumor necrosis factor-alpha modulates survival, proliferation, and neuronal differentiation in neonatal subventricular zone cell cultures.
Tumor necrosis factor (TNF)-alpha has been reported to modulate brain injury, but remarkably, little is known about its effects on neurogenesis. We report that TNF-alpha strongly influences survival, proliferation, and neuronal differentiation in cultured subventricular zone (SVZ) neural stem/progenitor cells derived from the neonatal P1-3 C57BL/6 mice. By using single-cell calcium imaging, we developed a method, based on cellular response to KCl and/or histamine, that allows the functional evaluation of neuronal differentiation. Exposure of SVZ cultures to 1 and 10 ng/ml mouse or 1 ng/ml human recombinant TNF-alpha resulted in increased differentiation of cells displaying a neuronal-like profile of [Ca2+](i) responses, compared with the predominant profile of immature cells observed in control, nontreated cultures. Moreover, by using neutralizing antibodies for each TNF-alpha receptor, we found that the proneurogenic effect of 1 ng/ml TNF-alpha is mediated via tumor necrosis factor receptor 1 activation. Accordingly, the percentage of neuronal nuclear protein-positive neurons was increased following exposure to mouse TNF-alpha. Interestingly, exposure of SVZ cultures to 1 ng/ml TNF-alpha induced cell proliferation, whereas 10 and 100 ng/ml TNF-alpha induced apoptotic cell death. Moreover, we found that exposure of SVZ cells to TNF-alpha for 15 minutes or 6 hours caused an increase in the phospho-stress-activated protein kinase/c-Jun N-terminal kinase immunoreactivity initially in the nucleus and then in growing axons, colocalizing with tau, consistent with axonogenesis. Taken together, these results show that TNF-alpha induces neurogenesis in neonatal SVZ cell cultures of mice. TNF-alpha, a proinflammatory cytokine and a proneurogenic factor, may play a central role in promoting neurogenesis and brain repair in response to brain injury and infection.
Bernardino
Liliana
L
Center for Neuroscience and Cell Biology, Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal.
Agasse
Fabienne
F
Silva
Bruno
B
Ferreira
Raquel
R
Grade
Sofia
S
Malva
João O
JO
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000166:cytology; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D055495:Neurogenesis; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D048031:JNK Mitogen-Activated Protein Kinases