Transient cytoskeletal alterations after SOD1 depletion in neuroblastoma cells

Abstract

We have studied the effects of superoxide production after Cu,Zn superoxide dismutase (SOD1) down-regulation by RNA interference. We demonstrated that SOD1 depletion induced, only in neuroblastoma cells, a decrease in actin and beta-tubulin content and accumulation of neurofilament light chain and Tau proteins. Alterations of cell morphology and the microfilament network were also observed, together with the up-regulation of the Cdk5/p35 pathway, which is involved in the regulation of actin polymerization. The decrease of filamentous actin was transient and was recovered through the activation of p38/Hsp27 MAPK pathway, as well as after treatment with N-acetyl-L-cysteine. The importance of p38 in the recovery of cytoskeleton was confirmed by experiments carried out in the presence of its inhibitor SB203580, which induced cell death. Our data demonstrate that SOD1 is essential for the preservation of cytoskeleton integrity, by maintaining physiological concentration of reactive oxygen species and inhibiting the activation of the neuronal specific Cdk5/p35 pathway.

Glutathione: new roles in redox signaling for an old antioxidant

“…Ultimately, the radical chain reactions will be blocked by the antioxidant enzymes superoxide dismutase (SOD) in association with catalase or GPX that determines the complete free radicals scavenging (Winterbourn, 1993). Indeed, we demonstrated that GSH finely compensates the decline of SOD1 activity in: (i) cells expressing less active SOD1 mutant found in familial amyotrophic lateral sclerosis (Ciriolo et al, 2001); (ii) cells in which SOD1 is down-regulated by RNA interference (Aquilano et al, 2006; Vigilanza et al, 2008). In particular, the initial burst of superoxide that cannot be eliminated efficiently due to the inactivity of SOD1 is promptly buffered by the induction of GSH synthesis resulting in protection against oxidative stress and cell death.…”

Alteration in Superoxide Dismutase 1 Causes Oxidative Stress and p38 MAPK Activation Following RVFV Infection

“…Earlier studies have revealed that SOD1 is involved in the regulation of cellular cytoskeleton and siRNA-mediated depletion of SOD1 caused alterations in actin cytoskeleton in neuroblastoma cell lines [41]. As a compensatory measure, activation of the p38 MAPK pathway was observed.…”

“…It was reported that in neuroblastoma cell lines, depletion of SOD1 caused early cytoskeletal alterations in the cells that ultimately activates pro-survival pathways [41]. The report shows that activation of Hsp27 occurs via the p38 MAPK cascade and that this activation is crucial to the survival of the cell.…”

Caloric Restriction and the Nutrient-Sensing PGC-1αin Mitochondrial Homeostasis: New Perspectives in Neurodegeneration

“…In particular, we have showed that the decline of glutathione (GSH), the most abundant nonenzymatic thiol antioxidant, is the primary cause of endogenous NO neurotoxicity, that is, characterized by a prominent protein damage via S-nitrosylation and nitration [13, 17]. In line with this evidence, also the decrease of enzymatic antioxidant for example, SOD1, result in a ROS-mediated damaging effect on cellular targets including mitochondria specifically in cells of neuronal origin [18, 19]. Therefore, the decline of antioxidant levels, generally occurring during physiological ageing, may be likely considered a key factor triggering NO/ROS-mediated neuronal death in ageing and neurodegenerative-related diseases.…”