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Role of P2X7 and P2Y2 receptors on α-secretase-dependent APP processing: Control of amyloid plaques formation "in vivo" by P2X7 receptor.

Miras-Portugal MT, Diaz-Hernandez JI, Gomez-Villafuertes R, Diaz-Hernandez M, Artalejo AR, Gualix J - Comput Struct Biotechnol J (2015)

Bottom Line: In Neuro-2a, a neuroblastoma cell line that constitutively expresses APP, activation of the P2X7 receptor leads to reduction of α-secretase activity, the opposite effect being obtained by P2Y2 receptor activation.In vivo inhibition of the P2X7 receptor induced a significant decrease in the number and size of hippocampal amyloid plaques.This reduction is mediated by an increase in the proteolytic processing of APP through α-secretase activity, which correlates with an increase in the phosphorylated form of GSK-3, a less active form of this enzyme.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry Department, School of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain, Institute of Neurochemistry (IUIN), Complutense University of Madrid, Madrid, Spain.

ABSTRACT
Amyloid precursor protein (APP) is expressed in a large variety of neural and non-neural cells. The balance between non-pathogenic and pathologic forms of APP processing, mediated by α-secretase and β-secretase respectively, remains a crucial step to understand β-amyloid, Aβ42 peptide, formation and aggregation that are at the origin of the senile plaques in the brain, a characteristic hallmark of Alzheimer's disease (AD). In Neuro-2a, a neuroblastoma cell line that constitutively expresses APP, activation of the P2X7 receptor leads to reduction of α-secretase activity, the opposite effect being obtained by P2Y2 receptor activation. The in vivo approach was made possible by the use of J20 mice, a transgenic mouse model of familial Alzheimer's disease (FAD) expressing human APP mutant protein. This animal exhibits prominent amyloid plaques by six months of age. In vivo inhibition of the P2X7 receptor induced a significant decrease in the number and size of hippocampal amyloid plaques. This reduction is mediated by an increase in the proteolytic processing of APP through α-secretase activity, which correlates with an increase in the phosphorylated form of GSK-3, a less active form of this enzyme. The in vivo findings corroborate the therapeutic potential of P2X7 antagonists in the treatment of FAD.

No MeSH data available.


Related in: MedlinePlus

Purinergic receptors regulate α-secretase and GSK-3 activities in N2a cells. (A) Protein levels of CTF C83 detected in N2a cells treated with the P2Y2R agonist Up4U (1 μM), both suramin (100 μM) and Up4U (1 μM), BzATP (100 μM), A438079 (1 μM), BBG (1 μM), or SB216763 (1 μM). Histogram represents the mean ± SEM of CTF C83/α-tubulin ratios normalized to control untreated cells (n = 4 independent experiments in duplicate). (B) Western blot detection of p-GSK-3β (pSer9) and total GSK-3 in N2a cells treated with BBG (1 μM), A438079 (1 μM) or BzATP (100 μM). Histogram represents the mean ± SEM of p-GSK-3β/total GSK-3β ratios (n = 3 independent experiments in duplicate). In all cases, α-tubulin was used as loading control, and ratios were normalized to control untreated cells (100%). *p < 0.05, **p < 0.01, ***p < 0.005 compared to control using ANOVA with Dunnet´s post-test analysis. For methods see Ref. [49].
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f0015: Purinergic receptors regulate α-secretase and GSK-3 activities in N2a cells. (A) Protein levels of CTF C83 detected in N2a cells treated with the P2Y2R agonist Up4U (1 μM), both suramin (100 μM) and Up4U (1 μM), BzATP (100 μM), A438079 (1 μM), BBG (1 μM), or SB216763 (1 μM). Histogram represents the mean ± SEM of CTF C83/α-tubulin ratios normalized to control untreated cells (n = 4 independent experiments in duplicate). (B) Western blot detection of p-GSK-3β (pSer9) and total GSK-3 in N2a cells treated with BBG (1 μM), A438079 (1 μM) or BzATP (100 μM). Histogram represents the mean ± SEM of p-GSK-3β/total GSK-3β ratios (n = 3 independent experiments in duplicate). In all cases, α-tubulin was used as loading control, and ratios were normalized to control untreated cells (100%). *p < 0.05, **p < 0.01, ***p < 0.005 compared to control using ANOVA with Dunnet´s post-test analysis. For methods see Ref. [49].

Mentions: P2Y2 receptor agonists are able to significantly increase the α-secretase-mediated APP processing in N2a cells, this stimulatory effect being consequently blocked by the broad spectrum P2 antagonist, suramin, as shown in Fig. 3A. These results agree with those obtained by other groups (as Gary Weisman's group), supporting the role of P2Y2 receptor in neuroprotection, an effect that is mediated at least in part via the activation of the APP non-amyloidogenic pathway through α-secretase processing [31–33,40].


Role of P2X7 and P2Y2 receptors on α-secretase-dependent APP processing: Control of amyloid plaques formation "in vivo" by P2X7 receptor.

Miras-Portugal MT, Diaz-Hernandez JI, Gomez-Villafuertes R, Diaz-Hernandez M, Artalejo AR, Gualix J - Comput Struct Biotechnol J (2015)

Purinergic receptors regulate α-secretase and GSK-3 activities in N2a cells. (A) Protein levels of CTF C83 detected in N2a cells treated with the P2Y2R agonist Up4U (1 μM), both suramin (100 μM) and Up4U (1 μM), BzATP (100 μM), A438079 (1 μM), BBG (1 μM), or SB216763 (1 μM). Histogram represents the mean ± SEM of CTF C83/α-tubulin ratios normalized to control untreated cells (n = 4 independent experiments in duplicate). (B) Western blot detection of p-GSK-3β (pSer9) and total GSK-3 in N2a cells treated with BBG (1 μM), A438079 (1 μM) or BzATP (100 μM). Histogram represents the mean ± SEM of p-GSK-3β/total GSK-3β ratios (n = 3 independent experiments in duplicate). In all cases, α-tubulin was used as loading control, and ratios were normalized to control untreated cells (100%). *p < 0.05, **p < 0.01, ***p < 0.005 compared to control using ANOVA with Dunnet´s post-test analysis. For methods see Ref. [49].
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4372621&req=5

f0015: Purinergic receptors regulate α-secretase and GSK-3 activities in N2a cells. (A) Protein levels of CTF C83 detected in N2a cells treated with the P2Y2R agonist Up4U (1 μM), both suramin (100 μM) and Up4U (1 μM), BzATP (100 μM), A438079 (1 μM), BBG (1 μM), or SB216763 (1 μM). Histogram represents the mean ± SEM of CTF C83/α-tubulin ratios normalized to control untreated cells (n = 4 independent experiments in duplicate). (B) Western blot detection of p-GSK-3β (pSer9) and total GSK-3 in N2a cells treated with BBG (1 μM), A438079 (1 μM) or BzATP (100 μM). Histogram represents the mean ± SEM of p-GSK-3β/total GSK-3β ratios (n = 3 independent experiments in duplicate). In all cases, α-tubulin was used as loading control, and ratios were normalized to control untreated cells (100%). *p < 0.05, **p < 0.01, ***p < 0.005 compared to control using ANOVA with Dunnet´s post-test analysis. For methods see Ref. [49].
Mentions: P2Y2 receptor agonists are able to significantly increase the α-secretase-mediated APP processing in N2a cells, this stimulatory effect being consequently blocked by the broad spectrum P2 antagonist, suramin, as shown in Fig. 3A. These results agree with those obtained by other groups (as Gary Weisman's group), supporting the role of P2Y2 receptor in neuroprotection, an effect that is mediated at least in part via the activation of the APP non-amyloidogenic pathway through α-secretase processing [31–33,40].

Bottom Line: In Neuro-2a, a neuroblastoma cell line that constitutively expresses APP, activation of the P2X7 receptor leads to reduction of α-secretase activity, the opposite effect being obtained by P2Y2 receptor activation.In vivo inhibition of the P2X7 receptor induced a significant decrease in the number and size of hippocampal amyloid plaques.This reduction is mediated by an increase in the proteolytic processing of APP through α-secretase activity, which correlates with an increase in the phosphorylated form of GSK-3, a less active form of this enzyme.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry Department, School of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain, Institute of Neurochemistry (IUIN), Complutense University of Madrid, Madrid, Spain.

ABSTRACT
Amyloid precursor protein (APP) is expressed in a large variety of neural and non-neural cells. The balance between non-pathogenic and pathologic forms of APP processing, mediated by α-secretase and β-secretase respectively, remains a crucial step to understand β-amyloid, Aβ42 peptide, formation and aggregation that are at the origin of the senile plaques in the brain, a characteristic hallmark of Alzheimer's disease (AD). In Neuro-2a, a neuroblastoma cell line that constitutively expresses APP, activation of the P2X7 receptor leads to reduction of α-secretase activity, the opposite effect being obtained by P2Y2 receptor activation. The in vivo approach was made possible by the use of J20 mice, a transgenic mouse model of familial Alzheimer's disease (FAD) expressing human APP mutant protein. This animal exhibits prominent amyloid plaques by six months of age. In vivo inhibition of the P2X7 receptor induced a significant decrease in the number and size of hippocampal amyloid plaques. This reduction is mediated by an increase in the proteolytic processing of APP through α-secretase activity, which correlates with an increase in the phosphorylated form of GSK-3, a less active form of this enzyme. The in vivo findings corroborate the therapeutic potential of P2X7 antagonists in the treatment of FAD.

No MeSH data available.


Related in: MedlinePlus