Sion may be affected in this pathological background. We used a

Sion may be affected in this pathological background. We used a transgenic PDAPP mouse model, which over-expresses human APP carrying the V717F mutation [20]. These mice progressively develop many of the pathological hallmarks of AD, although they do not suffer significant neuronal loss nordemonstrate neurofibrillary tangle pathology [21]. To investigate Sirt3 GSK2256098 web expression during disease progression, and in different CNS areas, we studied Sirt3 mRNA in cortex, hippocampus and GSK864 site cerebellum of 6- and 26-month-old wild-type (WT) and PDAPP mice. Compared with WT littermates Sirt3 mRNA was significantly upregulated in the PDAPP hippocampus at 6 months, while neither cortex nor cerebellum showed significant dysregulation at this stage (Fig. 3A). At 26 months, Sirt3 mRNA was significantly increased in PDAPP cortex, while neither hippocampus nor cerebellum showed significant alterations (Fig. 3B). Sirt3 mRNA expression thus mirrored the previously demonstrated spatiotemporal pattern of Ab-deposition in this strain of PDAPP transgenic mice, occurring first in hippocampus, later in cortex and in very low amounts at any age in cerebellum [22]. Sirt5 mRNA expression remained unchanged in CNS areas and at times where significant Sirt3 mRNA changes were observed, suggesting that Ab effects are specific for Sirt3 (Fig. 3C).Sirt3 Expression is Upregulated in Human Alzheimer’s Disease (AD)As neurodegeneration in AD is associated with significant increases in neuronal ROS production [2], we investigatedCNS SIRT3 in AD Mitochondrial StressFigure 3. Sirt3 mRNA is upregulated in a specific spatio-temporal pattern in a mouse model of AD. A. Sirt3 mRNA expression is significantly upregulated in hippocampus samples of 6 months-old PDAPP mice (n = 9210, ***P,0.001) with no alteration in cortex (n = 10) and cerebellum (n = 10). Sirt3 mRNA was measured and normalized to 18S rRNA using TaqMan multiplex QPCR. B. Sirt3 mRNA expression is significantly upregulated in cortex samples of 26 months-old PDAPP mice (n = 627, ***P,0.001) with no alteration in hippocampus (n = 8) and cerebellum (n = 627). C. Sirt5 mRNA is unaltered in 6 months-old hippocampus and 26 months-old cortex PDAPP samples. doi:10.1371/journal.pone.0048225.gwhether the expression of Sirt3 might be altered in this disease in humans. We studied brain tissue from cases of neuropathologically confirmed sporadic AD and matched controls (Table S1 and Fig. S4), focusing on the temporal cortex as a brain region heavily affected in AD. Since AD is associated with significant neuronal cell loss, we calibrated Sirt3 mRNA expression against expression of neuron-specific enolase (Eno2) [23]. Sirt3 mRNA was significantly increased in the AD group (Fig. 4A). The level of cleaved (active) SIRT3 protein was also increased in temporal cortex from AD patients (Fig. 4B).DiscussionCollectively our in vitro, AD mouse model and human AD post mortem tissue data suggest a neuroprotective role for SIRT3 in CNS mechanisms dealing with mitochondrial stress, including during AD progression. Presumably this role for SIRT3 extends to other neurodegenerative diseases where mitochondrial oxidative stress is a key component of neuronal decline, including Parkinson’s disease and multiple sclerosis.Figure 4. Sirt3 is upregulated in human Alzheimer’s disease (AD). A. Sirt3 mRNA expression is significantly increased in AD temporal cortex samples compared to matched controls (n = 14, **P,0.01). Protein and RNA were extracted from neuropatholo.Sion may be affected in this pathological background. We used a transgenic PDAPP mouse model, which over-expresses human APP carrying the V717F mutation [20]. These mice progressively develop many of the pathological hallmarks of AD, although they do not suffer significant neuronal loss nordemonstrate neurofibrillary tangle pathology [21]. To investigate Sirt3 expression during disease progression, and in different CNS areas, we studied Sirt3 mRNA in cortex, hippocampus and cerebellum of 6- and 26-month-old wild-type (WT) and PDAPP mice. Compared with WT littermates Sirt3 mRNA was significantly upregulated in the PDAPP hippocampus at 6 months, while neither cortex nor cerebellum showed significant dysregulation at this stage (Fig. 3A). At 26 months, Sirt3 mRNA was significantly increased in PDAPP cortex, while neither hippocampus nor cerebellum showed significant alterations (Fig. 3B). Sirt3 mRNA expression thus mirrored the previously demonstrated spatiotemporal pattern of Ab-deposition in this strain of PDAPP transgenic mice, occurring first in hippocampus, later in cortex and in very low amounts at any age in cerebellum [22]. Sirt5 mRNA expression remained unchanged in CNS areas and at times where significant Sirt3 mRNA changes were observed, suggesting that Ab effects are specific for Sirt3 (Fig. 3C).Sirt3 Expression is Upregulated in Human Alzheimer’s Disease (AD)As neurodegeneration in AD is associated with significant increases in neuronal ROS production [2], we investigatedCNS SIRT3 in AD Mitochondrial StressFigure 3. Sirt3 mRNA is upregulated in a specific spatio-temporal pattern in a mouse model of AD. A. Sirt3 mRNA expression is significantly upregulated in hippocampus samples of 6 months-old PDAPP mice (n = 9210, ***P,0.001) with no alteration in cortex (n = 10) and cerebellum (n = 10). Sirt3 mRNA was measured and normalized to 18S rRNA using TaqMan multiplex QPCR. B. Sirt3 mRNA expression is significantly upregulated in cortex samples of 26 months-old PDAPP mice (n = 627, ***P,0.001) with no alteration in hippocampus (n = 8) and cerebellum (n = 627). C. Sirt5 mRNA is unaltered in 6 months-old hippocampus and 26 months-old cortex PDAPP samples. doi:10.1371/journal.pone.0048225.gwhether the expression of Sirt3 might be altered in this disease in humans. We studied brain tissue from cases of neuropathologically confirmed sporadic AD and matched controls (Table S1 and Fig. S4), focusing on the temporal cortex as a brain region heavily affected in AD. Since AD is associated with significant neuronal cell loss, we calibrated Sirt3 mRNA expression against expression of neuron-specific enolase (Eno2) [23]. Sirt3 mRNA was significantly increased in the AD group (Fig. 4A). The level of cleaved (active) SIRT3 protein was also increased in temporal cortex from AD patients (Fig. 4B).DiscussionCollectively our in vitro, AD mouse model and human AD post mortem tissue data suggest a neuroprotective role for SIRT3 in CNS mechanisms dealing with mitochondrial stress, including during AD progression. Presumably this role for SIRT3 extends to other neurodegenerative diseases where mitochondrial oxidative stress is a key component of neuronal decline, including Parkinson’s disease and multiple sclerosis.Figure 4. Sirt3 is upregulated in human Alzheimer’s disease (AD). A. Sirt3 mRNA expression is significantly increased in AD temporal cortex samples compared to matched controls (n = 14, **P,0.01). Protein and RNA were extracted from neuropatholo.