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Expression of a Cu,Zn superoxide dismutase typical for familial amyotrophic lateral sclerosis increases the vulnerability of neuroblastoma cells to infectious injury.

Goos M, Zech WD, Jaiswal MK, Balakrishnan S, Ebert S, Mitchell T, Carrì MT, Keller BU, Nau R - BMC Infect. Dis. (2007)

Bottom Line: Mutations in the anti-oxidant enzyme Cu,Zn superoxide dismutase (EC 1.15.1.1, SOD1) are associated with familial ALS.Cell viability and apoptotic cell death were compared morphologically and by in-situ tailing.These findings link infection and motor neuron disease and suggest early treatment of respiratory infections in ALS patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, Georg-August-University of Göttingen, Göttingen, Germany. mlotz@gwdg.de

ABSTRACT

Background: Infections can aggravate the course of neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Mutations in the anti-oxidant enzyme Cu,Zn superoxide dismutase (EC 1.15.1.1, SOD1) are associated with familial ALS. Streptococcus pneumoniae, the most frequent respiratory pathogen, causes damage by the action of the cholesterol-binding virulence factor pneumolysin and by stimulation of the innate immune system, particularly via Toll-like-receptor 2.

Methods: SH-SY5Y neuroblastoma cells transfected with the G93A mutant of SOD1 typical for familial ALS (G93A-SOD1) and SH-SY5Y neuroblastoma cells transfected with wildtype SOD1 were both exposed to pneumolysin and in co-cultures with cultured human macrophages treated with the Toll like receptor 2 agonist N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-[R]-cysteinyl-[S]-seryl-[S]-lysyl-[S]-lysyl-[S]-lysyl-[S]-lysyl-[S]-lysine x 3 HCl (Pam3CSK4). Cell viability and apoptotic cell death were compared morphologically and by in-situ tailing. With the help of the WST-1 test, cell viability was quantified, and by measurement of neuron-specific enolase in the culture supernatant neuronal damage in co-cultures was investigated. Intracellular calcium levels were measured by fluorescence analysis using fura-2 AM.

Results: SH-SY5Y neuroblastoma cells transfected with the G93A mutant of SOD1 typical for familial ALS (G93A-SOD1) were more vulnerable to the neurotoxic action of pneumolysin and to the attack of monocytes stimulated by Pam3CSK4 than SH-SY5Y cells transfected with wild-type human SOD1. The enhanced pneumolysin toxicity in G93A-SOD1 neuronal cells depended on the inability of these cells to cope with an increased calcium influx caused by pores formed by pneumolysin. This inability was caused by an impaired capacity of the mitochondria to remove cytoplasmic calcium. Treatment of G93A-SOD1 SH-SY5Y neuroblastoma cells with the antioxidant N-acetylcysteine reduced the toxicity of pneumolysin.

Conclusion: The particular vulnerability of G93A-SOD1 neuronal cells to hemolysins and inflammation may be partly responsible for the clinical deterioration of ALS patients during infections. These findings link infection and motor neuron disease and suggest early treatment of respiratory infections in ALS patients.

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Strongly elevated calcium influx into G 93A-SOD1 neuroblastoma cells in comparison to wild-type SOD1 cells. Comparison of the intracellular calcium concentration-versus-time curves (n = 25 cells each; means ± SD; p < 0.0001).
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Figure 7: Strongly elevated calcium influx into G 93A-SOD1 neuroblastoma cells in comparison to wild-type SOD1 cells. Comparison of the intracellular calcium concentration-versus-time curves (n = 25 cells each; means ± SD; p < 0.0001).

Mentions: For a period of 20 minutes both cell lines were treated with pneumolysin in concentrations of 0.5 μg/ml. During this time cytoplasmic calcium levels were measured in both cell lines. Fig. 6 shows intracellular calcium levels [Ca2+]i as cytoplasmic calcium-versus-time curves in two representative cells during pneumolysin treatment. The ability of G93A-transfected SH-SY5Y cells to maintain low cytoplasmic calcium levels was strongly reduced. Analysis of the cytoplasmic calcium-versus-time curves of 25 G93A-SOD1 transfected and 25 Wt-SOD1 transfected cells after exposure to pneumolysin for 20 minutes revealed an approximately 4-fold increase of the area under the curve (AUC) in G93A-SOD1 SH-SY5Y cells (634.0 ± 309.0 in Wt-SOD SH-SY5Y versus 2658.0 ± 502.3 in G93A-SOD1 SH-SY5Y cells, p < 0.0001) (Fig. 7). The pneumolysin-induced [Ca2+]i peak values in G93A-SOD1 cells amounted to approximately 1.6-fold of the corresponding [Ca2+]i peak values in Wt-SOD1 cells (3.1 ± 0.4 versus 1.9 ± 0.5, p < 0.0001) (Fig. 8).


Expression of a Cu,Zn superoxide dismutase typical for familial amyotrophic lateral sclerosis increases the vulnerability of neuroblastoma cells to infectious injury.

Goos M, Zech WD, Jaiswal MK, Balakrishnan S, Ebert S, Mitchell T, Carrì MT, Keller BU, Nau R - BMC Infect. Dis. (2007)

Strongly elevated calcium influx into G 93A-SOD1 neuroblastoma cells in comparison to wild-type SOD1 cells. Comparison of the intracellular calcium concentration-versus-time curves (n = 25 cells each; means ± SD; p < 0.0001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2211486&req=5

Figure 7: Strongly elevated calcium influx into G 93A-SOD1 neuroblastoma cells in comparison to wild-type SOD1 cells. Comparison of the intracellular calcium concentration-versus-time curves (n = 25 cells each; means ± SD; p < 0.0001).
Mentions: For a period of 20 minutes both cell lines were treated with pneumolysin in concentrations of 0.5 μg/ml. During this time cytoplasmic calcium levels were measured in both cell lines. Fig. 6 shows intracellular calcium levels [Ca2+]i as cytoplasmic calcium-versus-time curves in two representative cells during pneumolysin treatment. The ability of G93A-transfected SH-SY5Y cells to maintain low cytoplasmic calcium levels was strongly reduced. Analysis of the cytoplasmic calcium-versus-time curves of 25 G93A-SOD1 transfected and 25 Wt-SOD1 transfected cells after exposure to pneumolysin for 20 minutes revealed an approximately 4-fold increase of the area under the curve (AUC) in G93A-SOD1 SH-SY5Y cells (634.0 ± 309.0 in Wt-SOD SH-SY5Y versus 2658.0 ± 502.3 in G93A-SOD1 SH-SY5Y cells, p < 0.0001) (Fig. 7). The pneumolysin-induced [Ca2+]i peak values in G93A-SOD1 cells amounted to approximately 1.6-fold of the corresponding [Ca2+]i peak values in Wt-SOD1 cells (3.1 ± 0.4 versus 1.9 ± 0.5, p < 0.0001) (Fig. 8).

Bottom Line: Mutations in the anti-oxidant enzyme Cu,Zn superoxide dismutase (EC 1.15.1.1, SOD1) are associated with familial ALS.Cell viability and apoptotic cell death were compared morphologically and by in-situ tailing.These findings link infection and motor neuron disease and suggest early treatment of respiratory infections in ALS patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, Georg-August-University of Göttingen, Göttingen, Germany. mlotz@gwdg.de

ABSTRACT

Background: Infections can aggravate the course of neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Mutations in the anti-oxidant enzyme Cu,Zn superoxide dismutase (EC 1.15.1.1, SOD1) are associated with familial ALS. Streptococcus pneumoniae, the most frequent respiratory pathogen, causes damage by the action of the cholesterol-binding virulence factor pneumolysin and by stimulation of the innate immune system, particularly via Toll-like-receptor 2.

Methods: SH-SY5Y neuroblastoma cells transfected with the G93A mutant of SOD1 typical for familial ALS (G93A-SOD1) and SH-SY5Y neuroblastoma cells transfected with wildtype SOD1 were both exposed to pneumolysin and in co-cultures with cultured human macrophages treated with the Toll like receptor 2 agonist N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)-propyl]-[R]-cysteinyl-[S]-seryl-[S]-lysyl-[S]-lysyl-[S]-lysyl-[S]-lysyl-[S]-lysine x 3 HCl (Pam3CSK4). Cell viability and apoptotic cell death were compared morphologically and by in-situ tailing. With the help of the WST-1 test, cell viability was quantified, and by measurement of neuron-specific enolase in the culture supernatant neuronal damage in co-cultures was investigated. Intracellular calcium levels were measured by fluorescence analysis using fura-2 AM.

Results: SH-SY5Y neuroblastoma cells transfected with the G93A mutant of SOD1 typical for familial ALS (G93A-SOD1) were more vulnerable to the neurotoxic action of pneumolysin and to the attack of monocytes stimulated by Pam3CSK4 than SH-SY5Y cells transfected with wild-type human SOD1. The enhanced pneumolysin toxicity in G93A-SOD1 neuronal cells depended on the inability of these cells to cope with an increased calcium influx caused by pores formed by pneumolysin. This inability was caused by an impaired capacity of the mitochondria to remove cytoplasmic calcium. Treatment of G93A-SOD1 SH-SY5Y neuroblastoma cells with the antioxidant N-acetylcysteine reduced the toxicity of pneumolysin.

Conclusion: The particular vulnerability of G93A-SOD1 neuronal cells to hemolysins and inflammation may be partly responsible for the clinical deterioration of ALS patients during infections. These findings link infection and motor neuron disease and suggest early treatment of respiratory infections in ALS patients.

Show MeSH
Related in: MedlinePlus