Limits...
Sigma-1 receptor agonist PRE084 is protective against mutant huntingtin-induced cell degeneration: involvement of calpastatin and the NF-κB pathway.

Hyrskyluoto A, Pulli I, Törnqvist K, Ho TH, Korhonen L, Lindholm D - Cell Death Dis (2013)

Bottom Line: Here we show that the Sig-1R agonist, PRE084 increases cell survival and counteracts the deleterious effects caused by N-terminal mutant huntingtin proteins in neuronal PC6.3 cells.Particularly, PRE084 increased the levels of cellular antioxidants by activating the NF-κB pathway that is compromised by the expression of mutant huntingtin proteins.These results show that the Sig-1R agonist has beneficial effects in models of HD and that compounds affecting the Sig-1R may be promising targets for future drug development in HD.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedicine/Biochemistry and Developmental Biology, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland.

ABSTRACT
Alterations in mitochondria and increased oxidative stress are associated with the disease progression in Huntington's disease (HD). Endoplasmic reticulum (ER) stress and oxidative damage are linked through the close communication between the ER and mitochondria. Sigma-1 receptor (Sig-1R) is a chaperone protein in the ER that is involved in ER stress regulation, but little is known about its role in HD or the mechanisms for cell protection. Here we show that the Sig-1R agonist, PRE084 increases cell survival and counteracts the deleterious effects caused by N-terminal mutant huntingtin proteins in neuronal PC6.3 cells. Particularly, PRE084 increased the levels of cellular antioxidants by activating the NF-κB pathway that is compromised by the expression of mutant huntingtin proteins. These results show that the Sig-1R agonist has beneficial effects in models of HD and that compounds affecting the Sig-1R may be promising targets for future drug development in HD.

Show MeSH

Related in: MedlinePlus

No effects of huntingtin proteins and PRE084 on mitochondrial calcium responses. Mitochondrial Ca2+ concentrations were measured in PRE084-treated and in huntingtin protein-overexpressing cells as described in the Materials and Methods. (a and b) Representative traces of mitochondrial Ca2+ concentrations ([Ca2+]mito) in PC6.3 cells expressing FL huntingtin constructs having 17 (17QFL) and 75 polyglutamine (75QFL) repeats and employing stimulations with 100 nM bradykinin. C, control plasmid pcDNA-expressing cells. Panel a is without pretreatment and panel b is pretreatment for 20 h with 0.3 μM PRE084. There were no significant changes in [Ca2+]mito. between controls and PRE084-pretreated cells or after expressing of the mutant huntingtin proteins. (c and d) Summary histograms. Values are means±S.D., n=4. There was a tendency to higher [Ca2+]mito following PRE084 treatment but these were not statistically significant from controls
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3674377&req=5

fig3: No effects of huntingtin proteins and PRE084 on mitochondrial calcium responses. Mitochondrial Ca2+ concentrations were measured in PRE084-treated and in huntingtin protein-overexpressing cells as described in the Materials and Methods. (a and b) Representative traces of mitochondrial Ca2+ concentrations ([Ca2+]mito) in PC6.3 cells expressing FL huntingtin constructs having 17 (17QFL) and 75 polyglutamine (75QFL) repeats and employing stimulations with 100 nM bradykinin. C, control plasmid pcDNA-expressing cells. Panel a is without pretreatment and panel b is pretreatment for 20 h with 0.3 μM PRE084. There were no significant changes in [Ca2+]mito. between controls and PRE084-pretreated cells or after expressing of the mutant huntingtin proteins. (c and d) Summary histograms. Values are means±S.D., n=4. There was a tendency to higher [Ca2+]mito following PRE084 treatment but these were not statistically significant from controls

Mentions: Previous data shows that mutant huntingtin can modulate calcium signaling in neuronal cells through an interaction with IP3R1,18 and hat IP3R1 is negatively regulated in a mouse model for HD.19 Sig-1R is enriched within the MAM region in the ER13 and influences Ca2+ signaling from ER into mitochondria by stabilizing IP3R. Given the regulation of Sig-1R by mutant huntingtin (Figure 1), we were interested to study whether the mutant huntingtin proteins may also influence mitochondrial [Ca2+] ([Ca2+]mito) during IP3-induced calcium release and whether PRE084 may affect this. To accomplish this, cells were transfected with aequorin targeted to the mitochondrial matrix in conjunction with plasmids expressing either the full-length 17QFL huntingtin or the disease-causing 75Q huntingtin protein plasmids. Control cells were co-transfected with the vector plasmid. The cells were left untreated or pretreated with 0.3 μM PRE084 for 20 h followed by stimulation with 100 nM bradykinin, and the [Ca2+]mito was then measured as described in the Materials and methods. Data showed that neither 17QFL nor 75QFL huntingtin altered [Ca2+]mito in the cells when compared with untreated controls (Figures 3a and c). Incubation with PRE084 led to a slight increased [Ca2+]mito response but this was not significant and [Ca2+]mito was not changed in cells expressing 17QFL or 75QFL huntingtin compared with the control (Figures 3b and d). Taken together, the results show that the mutant huntingtin proteins did not influence mitochondrial [Ca2+] levels in neuronal PC6.3 cells. In keeping with our previous data using120Q mutant fragment huntingtin protein,9 the expression of 75QFL also did not elevate cytosolic Ca2+ in the PC6.3 neuronal cells (Supplementary Figure 3).


Sigma-1 receptor agonist PRE084 is protective against mutant huntingtin-induced cell degeneration: involvement of calpastatin and the NF-κB pathway.

Hyrskyluoto A, Pulli I, Törnqvist K, Ho TH, Korhonen L, Lindholm D - Cell Death Dis (2013)

No effects of huntingtin proteins and PRE084 on mitochondrial calcium responses. Mitochondrial Ca2+ concentrations were measured in PRE084-treated and in huntingtin protein-overexpressing cells as described in the Materials and Methods. (a and b) Representative traces of mitochondrial Ca2+ concentrations ([Ca2+]mito) in PC6.3 cells expressing FL huntingtin constructs having 17 (17QFL) and 75 polyglutamine (75QFL) repeats and employing stimulations with 100 nM bradykinin. C, control plasmid pcDNA-expressing cells. Panel a is without pretreatment and panel b is pretreatment for 20 h with 0.3 μM PRE084. There were no significant changes in [Ca2+]mito. between controls and PRE084-pretreated cells or after expressing of the mutant huntingtin proteins. (c and d) Summary histograms. Values are means±S.D., n=4. There was a tendency to higher [Ca2+]mito following PRE084 treatment but these were not statistically significant from controls
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3674377&req=5

fig3: No effects of huntingtin proteins and PRE084 on mitochondrial calcium responses. Mitochondrial Ca2+ concentrations were measured in PRE084-treated and in huntingtin protein-overexpressing cells as described in the Materials and Methods. (a and b) Representative traces of mitochondrial Ca2+ concentrations ([Ca2+]mito) in PC6.3 cells expressing FL huntingtin constructs having 17 (17QFL) and 75 polyglutamine (75QFL) repeats and employing stimulations with 100 nM bradykinin. C, control plasmid pcDNA-expressing cells. Panel a is without pretreatment and panel b is pretreatment for 20 h with 0.3 μM PRE084. There were no significant changes in [Ca2+]mito. between controls and PRE084-pretreated cells or after expressing of the mutant huntingtin proteins. (c and d) Summary histograms. Values are means±S.D., n=4. There was a tendency to higher [Ca2+]mito following PRE084 treatment but these were not statistically significant from controls
Mentions: Previous data shows that mutant huntingtin can modulate calcium signaling in neuronal cells through an interaction with IP3R1,18 and hat IP3R1 is negatively regulated in a mouse model for HD.19 Sig-1R is enriched within the MAM region in the ER13 and influences Ca2+ signaling from ER into mitochondria by stabilizing IP3R. Given the regulation of Sig-1R by mutant huntingtin (Figure 1), we were interested to study whether the mutant huntingtin proteins may also influence mitochondrial [Ca2+] ([Ca2+]mito) during IP3-induced calcium release and whether PRE084 may affect this. To accomplish this, cells were transfected with aequorin targeted to the mitochondrial matrix in conjunction with plasmids expressing either the full-length 17QFL huntingtin or the disease-causing 75Q huntingtin protein plasmids. Control cells were co-transfected with the vector plasmid. The cells were left untreated or pretreated with 0.3 μM PRE084 for 20 h followed by stimulation with 100 nM bradykinin, and the [Ca2+]mito was then measured as described in the Materials and methods. Data showed that neither 17QFL nor 75QFL huntingtin altered [Ca2+]mito in the cells when compared with untreated controls (Figures 3a and c). Incubation with PRE084 led to a slight increased [Ca2+]mito response but this was not significant and [Ca2+]mito was not changed in cells expressing 17QFL or 75QFL huntingtin compared with the control (Figures 3b and d). Taken together, the results show that the mutant huntingtin proteins did not influence mitochondrial [Ca2+] levels in neuronal PC6.3 cells. In keeping with our previous data using120Q mutant fragment huntingtin protein,9 the expression of 75QFL also did not elevate cytosolic Ca2+ in the PC6.3 neuronal cells (Supplementary Figure 3).

Bottom Line: Here we show that the Sig-1R agonist, PRE084 increases cell survival and counteracts the deleterious effects caused by N-terminal mutant huntingtin proteins in neuronal PC6.3 cells.Particularly, PRE084 increased the levels of cellular antioxidants by activating the NF-κB pathway that is compromised by the expression of mutant huntingtin proteins.These results show that the Sig-1R agonist has beneficial effects in models of HD and that compounds affecting the Sig-1R may be promising targets for future drug development in HD.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedicine/Biochemistry and Developmental Biology, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland.

ABSTRACT
Alterations in mitochondria and increased oxidative stress are associated with the disease progression in Huntington's disease (HD). Endoplasmic reticulum (ER) stress and oxidative damage are linked through the close communication between the ER and mitochondria. Sigma-1 receptor (Sig-1R) is a chaperone protein in the ER that is involved in ER stress regulation, but little is known about its role in HD or the mechanisms for cell protection. Here we show that the Sig-1R agonist, PRE084 increases cell survival and counteracts the deleterious effects caused by N-terminal mutant huntingtin proteins in neuronal PC6.3 cells. Particularly, PRE084 increased the levels of cellular antioxidants by activating the NF-κB pathway that is compromised by the expression of mutant huntingtin proteins. These results show that the Sig-1R agonist has beneficial effects in models of HD and that compounds affecting the Sig-1R may be promising targets for future drug development in HD.

Show MeSH
Related in: MedlinePlus