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Deletion of the type-1 interferon receptor in APPSWE/PS1ΔE9 mice preserves cognitive function and alters glial phenotype.

Minter MR, Moore Z, Zhang M, Brody KM, Jones NC, Shultz SR, Taylor JM, Crack PJ - Acta Neuropathol Commun (2016)

Bottom Line: A neuro-inflammatory response is evident in Alzheimer's disease (AD), yet the precise mechanisms by which neuro-inflammation influences the progression of Alzheimer's disease (AD) remain poorly understood.These APPSWE/PS1ΔE9 x IFNAR1(-/-) microglial populations demonstrated an anti-inflammatory phenotype that was confirmed in vitro by soluble Aβ1-42 treatment of IFNAR1(-/-) primary glial cultures.Our findings suggest that modulating neuro-inflammatory responses by suppressing type-1 IFN signaling may provide therapeutic benefit in AD.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Therapeutics, University of Melbourne, 8th floor, Medical building, Grattan St, Parkville, Melbourne, 3010, Victoria, Australia.

ABSTRACT
A neuro-inflammatory response is evident in Alzheimer's disease (AD), yet the precise mechanisms by which neuro-inflammation influences the progression of Alzheimer's disease (AD) remain poorly understood. Type-1 interferons (IFNs) are master regulators of innate immunity and have been implicated in multiple CNS disorders, however their role in AD progression has not yet been fully investigated. Hence, we generated APPSWE/PS1ΔE9 mice lacking the type-1 IFN alpha receptor-1 (IFNAR1, APPSWE/PS1ΔE9 x IFNAR1(-/-)) aged to 9 months to investigate the role of type-1 IFN signaling in a well-validated model of AD. APPSWE/PS1ΔE9 x IFNAR1(-/-) mice displayed a modest reduction in Aβ monomer levels, despite maintenance of plaque deposition. This finding correlated with partial rescue of spatial learning and memory impairments in the Morris water maze in comparison to APPSWE/PS1ΔE9 mice. Q-PCR identified a reduced type-1 IFN response and modulated pro-inflammatory cytokine secretion in APPSWE/PS1ΔE9 x IFNAR1(-/-) mice compared to APPSWE/PS1ΔE9 mice. Interestingly, immunohistochemistry displayed enhanced astrocyte reactivity but attenuated microgliosis surrounding amyloid plaque deposits in APPSWE/PS1ΔE9 x IFNAR1(-/-) mice in comparison to APPSWE/PS1ΔE9 mice. These APPSWE/PS1ΔE9 x IFNAR1(-/-) microglial populations demonstrated an anti-inflammatory phenotype that was confirmed in vitro by soluble Aβ1-42 treatment of IFNAR1(-/-) primary glial cultures. Our findings suggest that modulating neuro-inflammatory responses by suppressing type-1 IFN signaling may provide therapeutic benefit in AD.

No MeSH data available.


Related in: MedlinePlus

The type-1 IFN and pro-inflammatory cytokine response is attenuated upon removal of IFNAR1 in APPSWE/PS1ΔE9 mice. a Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IFNα, IRF7, IRF3 and IRF8 transcript levels. b Representative immunoblot of Tris–HCl soluble cortical protein lysates isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice using anti-p-Stat-3. c Densitometry of cortical p-Stat-3 levels in APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice is shown. d Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IL-1β, IL-6 and TNFα transcript levels. For Q-PCR, all samples were normalized back to the Ct value of the housekeeping gene GAPDH (ΔCt). The mRNA of the variant genotype groups were then expressed relative to their gene-specific wildtype littermate controls (fold change, ΔΔCt). For densitometry, total Stat-3 levels were normalized to the β-actin loading control and p-Stat-3 intensity was calculated relative to this value (p-Stat-3/(Stat-3/β-actin). Intensity values of the APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mouse groups are expressed as fold change relative to wildtype littermate control levels (represented by the dashed line). Immunodetection of β-actin was used to ascertain loading quantities. Data are displayed as box plots box plots described in the statistical analysis section in Materials and Methods (Q-PCR: n = 9 per genotype; Western blotting: n = 4 per genotype; •represents outlier value; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001). See Additional file 2: Table S1 for further analysis
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Fig3: The type-1 IFN and pro-inflammatory cytokine response is attenuated upon removal of IFNAR1 in APPSWE/PS1ΔE9 mice. a Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IFNα, IRF7, IRF3 and IRF8 transcript levels. b Representative immunoblot of Tris–HCl soluble cortical protein lysates isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice using anti-p-Stat-3. c Densitometry of cortical p-Stat-3 levels in APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice is shown. d Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IL-1β, IL-6 and TNFα transcript levels. For Q-PCR, all samples were normalized back to the Ct value of the housekeeping gene GAPDH (ΔCt). The mRNA of the variant genotype groups were then expressed relative to their gene-specific wildtype littermate controls (fold change, ΔΔCt). For densitometry, total Stat-3 levels were normalized to the β-actin loading control and p-Stat-3 intensity was calculated relative to this value (p-Stat-3/(Stat-3/β-actin). Intensity values of the APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mouse groups are expressed as fold change relative to wildtype littermate control levels (represented by the dashed line). Immunodetection of β-actin was used to ascertain loading quantities. Data are displayed as box plots box plots described in the statistical analysis section in Materials and Methods (Q-PCR: n = 9 per genotype; Western blotting: n = 4 per genotype; •represents outlier value; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001). See Additional file 2: Table S1 for further analysis

Mentions: Previously it has been demonstrated that removal of IFNAR1 attenuates the type-1 IFN response to soluble Aβ1-42 in primary cultured neurons and confers neuro-protection [64]. To investigate alterations in the type-1 IFN response in APPSWE/PS1ΔE9 x IFNAR1−/− mice, Q-PCR was performed on cortical tissue. Levels of IFNα expression were significantly elevated in APPSWE/PS1ΔE9 mice compared to wildtype mice with this elevation attenuated in APPSWE/PS1ΔE9 x IFNAR1−/− mice (Wildtype: 1.0 ± 0.08-fold vs. APPSWE/PS1ΔE9: 3.4 ± 0.8-fold, p = 0.0009; APPSWE/PS1ΔE9: 3.4 ± 0.8-fold vs. APPSWE/PS1ΔE9 x IFNAR1−/−: 1.3 ± 0.1-fold, p = 0.0063, n = 9 per genotype, Fig. 3a). This data confirms that aged APPSWE/PS1ΔE9 display enhanced type-1 IFNα expression that is IFNAR1-dependent. We also analyzed IFNβ transcript levels in both wildtype and APPSWE/PS1ΔE9 cortical tissue but were unable to detect a difference between genotypes (n = 7 per genotype, Additional file 3: Figure S2).Fig. 3


Deletion of the type-1 interferon receptor in APPSWE/PS1ΔE9 mice preserves cognitive function and alters glial phenotype.

Minter MR, Moore Z, Zhang M, Brody KM, Jones NC, Shultz SR, Taylor JM, Crack PJ - Acta Neuropathol Commun (2016)

The type-1 IFN and pro-inflammatory cytokine response is attenuated upon removal of IFNAR1 in APPSWE/PS1ΔE9 mice. a Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IFNα, IRF7, IRF3 and IRF8 transcript levels. b Representative immunoblot of Tris–HCl soluble cortical protein lysates isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice using anti-p-Stat-3. c Densitometry of cortical p-Stat-3 levels in APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice is shown. d Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IL-1β, IL-6 and TNFα transcript levels. For Q-PCR, all samples were normalized back to the Ct value of the housekeeping gene GAPDH (ΔCt). The mRNA of the variant genotype groups were then expressed relative to their gene-specific wildtype littermate controls (fold change, ΔΔCt). For densitometry, total Stat-3 levels were normalized to the β-actin loading control and p-Stat-3 intensity was calculated relative to this value (p-Stat-3/(Stat-3/β-actin). Intensity values of the APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mouse groups are expressed as fold change relative to wildtype littermate control levels (represented by the dashed line). Immunodetection of β-actin was used to ascertain loading quantities. Data are displayed as box plots box plots described in the statistical analysis section in Materials and Methods (Q-PCR: n = 9 per genotype; Western blotting: n = 4 per genotype; •represents outlier value; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001). See Additional file 2: Table S1 for further analysis
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Fig3: The type-1 IFN and pro-inflammatory cytokine response is attenuated upon removal of IFNAR1 in APPSWE/PS1ΔE9 mice. a Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IFNα, IRF7, IRF3 and IRF8 transcript levels. b Representative immunoblot of Tris–HCl soluble cortical protein lysates isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice using anti-p-Stat-3. c Densitometry of cortical p-Stat-3 levels in APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mice is shown. d Q-PCR of cortical tissue isolated from 9 month old wildtype, IFNAR1−/−, APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− littermate controls analyzing IL-1β, IL-6 and TNFα transcript levels. For Q-PCR, all samples were normalized back to the Ct value of the housekeeping gene GAPDH (ΔCt). The mRNA of the variant genotype groups were then expressed relative to their gene-specific wildtype littermate controls (fold change, ΔΔCt). For densitometry, total Stat-3 levels were normalized to the β-actin loading control and p-Stat-3 intensity was calculated relative to this value (p-Stat-3/(Stat-3/β-actin). Intensity values of the APPSWE/PS1ΔE9 and APPSWE/PS1ΔE9 x IFNAR1−/− mouse groups are expressed as fold change relative to wildtype littermate control levels (represented by the dashed line). Immunodetection of β-actin was used to ascertain loading quantities. Data are displayed as box plots box plots described in the statistical analysis section in Materials and Methods (Q-PCR: n = 9 per genotype; Western blotting: n = 4 per genotype; •represents outlier value; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001). See Additional file 2: Table S1 for further analysis
Mentions: Previously it has been demonstrated that removal of IFNAR1 attenuates the type-1 IFN response to soluble Aβ1-42 in primary cultured neurons and confers neuro-protection [64]. To investigate alterations in the type-1 IFN response in APPSWE/PS1ΔE9 x IFNAR1−/− mice, Q-PCR was performed on cortical tissue. Levels of IFNα expression were significantly elevated in APPSWE/PS1ΔE9 mice compared to wildtype mice with this elevation attenuated in APPSWE/PS1ΔE9 x IFNAR1−/− mice (Wildtype: 1.0 ± 0.08-fold vs. APPSWE/PS1ΔE9: 3.4 ± 0.8-fold, p = 0.0009; APPSWE/PS1ΔE9: 3.4 ± 0.8-fold vs. APPSWE/PS1ΔE9 x IFNAR1−/−: 1.3 ± 0.1-fold, p = 0.0063, n = 9 per genotype, Fig. 3a). This data confirms that aged APPSWE/PS1ΔE9 display enhanced type-1 IFNα expression that is IFNAR1-dependent. We also analyzed IFNβ transcript levels in both wildtype and APPSWE/PS1ΔE9 cortical tissue but were unable to detect a difference between genotypes (n = 7 per genotype, Additional file 3: Figure S2).Fig. 3

Bottom Line: A neuro-inflammatory response is evident in Alzheimer's disease (AD), yet the precise mechanisms by which neuro-inflammation influences the progression of Alzheimer's disease (AD) remain poorly understood.These APPSWE/PS1ΔE9 x IFNAR1(-/-) microglial populations demonstrated an anti-inflammatory phenotype that was confirmed in vitro by soluble Aβ1-42 treatment of IFNAR1(-/-) primary glial cultures.Our findings suggest that modulating neuro-inflammatory responses by suppressing type-1 IFN signaling may provide therapeutic benefit in AD.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Therapeutics, University of Melbourne, 8th floor, Medical building, Grattan St, Parkville, Melbourne, 3010, Victoria, Australia.

ABSTRACT
A neuro-inflammatory response is evident in Alzheimer's disease (AD), yet the precise mechanisms by which neuro-inflammation influences the progression of Alzheimer's disease (AD) remain poorly understood. Type-1 interferons (IFNs) are master regulators of innate immunity and have been implicated in multiple CNS disorders, however their role in AD progression has not yet been fully investigated. Hence, we generated APPSWE/PS1ΔE9 mice lacking the type-1 IFN alpha receptor-1 (IFNAR1, APPSWE/PS1ΔE9 x IFNAR1(-/-)) aged to 9 months to investigate the role of type-1 IFN signaling in a well-validated model of AD. APPSWE/PS1ΔE9 x IFNAR1(-/-) mice displayed a modest reduction in Aβ monomer levels, despite maintenance of plaque deposition. This finding correlated with partial rescue of spatial learning and memory impairments in the Morris water maze in comparison to APPSWE/PS1ΔE9 mice. Q-PCR identified a reduced type-1 IFN response and modulated pro-inflammatory cytokine secretion in APPSWE/PS1ΔE9 x IFNAR1(-/-) mice compared to APPSWE/PS1ΔE9 mice. Interestingly, immunohistochemistry displayed enhanced astrocyte reactivity but attenuated microgliosis surrounding amyloid plaque deposits in APPSWE/PS1ΔE9 x IFNAR1(-/-) mice in comparison to APPSWE/PS1ΔE9 mice. These APPSWE/PS1ΔE9 x IFNAR1(-/-) microglial populations demonstrated an anti-inflammatory phenotype that was confirmed in vitro by soluble Aβ1-42 treatment of IFNAR1(-/-) primary glial cultures. Our findings suggest that modulating neuro-inflammatory responses by suppressing type-1 IFN signaling may provide therapeutic benefit in AD.

No MeSH data available.


Related in: MedlinePlus