Interleukin-18 alters protein expressions of neurodegenerative diseases-linked proteins in human SH-SY5Y neuron-like cells

Elina M Sutinen; Minna A Korolainen; Jukka Häyrinen; Irina Alafuzoff; Steven Petratos; Antero Salminen; Hilkka Soininen; Tuula Pirttilä; Johanna O Ojala

doi:10.3389/fncel.2014.00214

Interleukin-18 alters protein expressions of neurodegenerative diseases-linked proteins in human SH-SY5Y neuron-like cells

Front Cell Neurosci. 2014 Aug 7:8:214. doi: 10.3389/fncel.2014.00214. eCollection 2014.

Authors

Elina M Sutinen¹, Minna A Korolainen², Jukka Häyrinen³, Irina Alafuzoff⁴, Steven Petratos⁵, Antero Salminen⁶, Hilkka Soininen⁷, Tuula Pirttilä⁷, Johanna O Ojala¹

Affiliations

¹ Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland Kuopio, Finland ; Brain Research Unit, Clinical Research Centre, University of Eastern Finland Kuopio, Finland.
² Institute of Biotechnology, University of Helsinki Helsinki, Finland.
³ School of Medicine, Institute of Biomedicine, University of Eastern Finland Kuopio, Finland.
⁴ Rudbecklaboratoriet, Department of Immunology, Genetics and Pathology, Molecular and Morphological Pathology, Uppsala University Uppsala, Sweden.
⁵ Regenerative Neuroscience and Development Laboratory, Department of Medicine, Central Clinical School, Monash University Prahran, VIC, Australia.
⁶ Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland Kuopio, Finland ; Department of Neurology, Kuopio University Hospital Kuopio, Finland.
⁷ Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland Kuopio, Finland ; Brain Research Unit, Clinical Research Centre, University of Eastern Finland Kuopio, Finland ; Department of Neurology, Kuopio University Hospital Kuopio, Finland.

Abstract

Chronic inflammation and oxidative stress (OS) are present in Alzheimer's disease (AD) brains in addition to neuronal loss, Amyloid-β (Aβ) plaques and hyperphosphorylated tau-protein neurofibrillary tangles (NFTs). Previously we showed that levels of the pro-inflammatory cytokine, interleukin-18 (IL-18), are elevated in post-mortem AD brains. IL-18 can modulate the tau kinases, Cdk5 and GSK3β, as well as Aβ-production. IL-18 levels are also increased in AD risk diseases, including type-2 diabetes and obesity. Here, we explored other IL-18 regulated proteins in neuron-like SH-SY5Y cells. Differentiated SH-SY5Y cells, incubated with IL-18 for 24, 48, or 72 h, were analyzed by two-dimensional gel electrophoresis (2D-DIGE). Specific altered protein spots were chosen and identified with mass spectrometry (MS) and verified by western immunoblotting (WIB). IL-18 had time-dependent effects on the SH-SY5Y proteome, modulating numerous protein levels/modifications. We concentrated on those related to OS (DDAH2, peroxiredoxins 2, 3, and 6, DJ-1, BLVRA), Aβ-degradation (MMP14, TIMP2), Aβ-aggregation (Septin-2), and modifications of axon growth and guidance associated, collapsin response mediator protein 2 (CRMP2). IL-18 significantly increased antioxidative enzymes, indicative of OS, and altered levels of glycolytic α- and γ-enolase and multifunctional 14-3-3γ and -ε, commonly affected in neurodegenerative diseases. MMP14, TIMP2, α-enolase and 14-3-3ε, indirectly involved in Aβ metabolism, as well as Septin-2 showed changes that increase Aβ levels. Increased 14-3-3γ may contribute to GSK3β driven tau hyperphosphorylation and CRMP2 Thr514 and Ser522 phosphorylation with the Thr555-site, a target for Rho kinase, showing time-dependent changes. IL-18 also increased caspase-1 levels and vacuolization of the cells. Although our SH-SY5Y cells were not aged, as neurons in AD, our work suggests that heightened or prolonged IL-18 levels can drive protein changes of known relevance to AD pathogenesis.

Keywords: CRMP2; DDAH; Interleukin-18; MMP14; inflammation; neurodegenerative diseases; oxidative stress related proteins; proteomics.