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CRTC1 gene is differentially methylated in the human hippocampus in Alzheimer's disease.

Mendioroz M, Celarain N, Altuna M, Sánchez-Ruiz de Gordoa J, Zelaya MV, Roldán M, Rubio I, Larumbe R, Erro ME, Méndez I, Echávarri C - Alzheimers Res Ther (2016)

Bottom Line: Moreover, a 1.54-fold decrease in CRTC1 mRNA levels was observed in hippocampus of AD cases compared to controls (p < 0.05) supporting the notion that CRTC1 is downregulated in the AD hippocampus.DNA methylation levels within two distinct promoter regions of the CRTC1 gene were decreased in human hippocampus affected by AD compared with controls and methylation within Prom1 showed a strong inverse correlation with p-tau deposition.Further studies are guaranteed to elucidate the precise role that CRTC1 methylation plays in AD pathophysiology.

View Article: PubMed Central - PubMed

Affiliation: NeuroEpigenetics Laboratory, Navarrabiomed- IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, Pamplona, Navarra, 31008, Spain. maitemendilab@gmail.com.

ABSTRACT

Background: CRTC1 (CREB regulated transcription coactivator 1) gene plays a role in synaptic plasticity, learning and long-term memory formation in the hippocampus. Recently, CRTC1 has been shown to be downregulated in Alzheimer's disease (AD). Nevertheless, the mechanisms underlying CRTC1 dysregulation in AD remain unclear.

Methods: To understand better the epigenetic mechanisms regulating CRTC1 expression that may be altered in AD, we profiled DNA methylation at CpG site resolution by bisulfite cloning sequencing in two promoter regions (referred to as Prom1 and Prom2) of the CRTC1 gene in human hippocampus from controls and AD cases. Next, we correlated DNA methylation levels with AD-related pathology, i.e., β-amyloid and phosphorylated-tau (p-tau) burden and also measured CRTC1 mRNA levels by RT-qPCR.

Results: Methylation levels were lower in AD cases as compared to controls within both promoter regions (Prom1: 0.95% vs. 5%, p-value < 0.01 and Prom2: 2.80% vs. 17.80%, p-value < 0.001). Interestingly, CRTC1 methylation levels inversely correlated with AD-related neuropathological changes, particularly with p-tau deposition (rSpearman = -0.903, p < 0.001). Moreover, a 1.54-fold decrease in CRTC1 mRNA levels was observed in hippocampus of AD cases compared to controls (p < 0.05) supporting the notion that CRTC1 is downregulated in the AD hippocampus.

Conclusions: DNA methylation levels within two distinct promoter regions of the CRTC1 gene were decreased in human hippocampus affected by AD compared with controls and methylation within Prom1 showed a strong inverse correlation with p-tau deposition. Further studies are guaranteed to elucidate the precise role that CRTC1 methylation plays in AD pathophysiology.

No MeSH data available.


Related in: MedlinePlus

CRTC1 mRNA expression is decreased in human hippocampus in Alzheimer’s disease (AD). a The graph shows a significant 1.54-fold decrease in CRTC1 mRNA levels in AD hippocampal samples compared to control hippocampal samples. bCRTC1 mRNA expression decreases across AD stages, as shown when CRTC1 expression levels are sorted based on ABC score. Boxes represent percentage of CRTC1 expression relative to the geometric mean of GAPDH and ACTB housekeeping genes expression. Bars represent the standard error of the mean. *p-value < 0.05; ** p-value < 0.005. c Two different CRTC1 transcript variants are shown. CRTC1 variant 1 has 14 exons and CRTC1 variant 3 shares all the exons of variant 1 plus an additional exon 3. Black boxes represent exons, arrows represent transcription start sites and white boxes denote CpG islands. CpG cytosine-phosphate-guanine
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Fig2: CRTC1 mRNA expression is decreased in human hippocampus in Alzheimer’s disease (AD). a The graph shows a significant 1.54-fold decrease in CRTC1 mRNA levels in AD hippocampal samples compared to control hippocampal samples. bCRTC1 mRNA expression decreases across AD stages, as shown when CRTC1 expression levels are sorted based on ABC score. Boxes represent percentage of CRTC1 expression relative to the geometric mean of GAPDH and ACTB housekeeping genes expression. Bars represent the standard error of the mean. *p-value < 0.05; ** p-value < 0.005. c Two different CRTC1 transcript variants are shown. CRTC1 variant 1 has 14 exons and CRTC1 variant 3 shares all the exons of variant 1 plus an additional exon 3. Black boxes represent exons, arrows represent transcription start sites and white boxes denote CpG islands. CpG cytosine-phosphate-guanine

Mentions: To test if CRTC1 was differentially expressed in our cohort, we measured CRTC1 mRNA expression levels by RT-qPCR in hippocampal samples from Alzheimer’s disease (AD) cases and controls. Four samples did not pass the RNA quality threshold and so were not included in the experiments (see CRTC1 mRNA expression analysis in the Methods section). Eventually, 26 AD cases were compared to 12 controls. RT-qPCR reactions were performed in triplicate for each sample and repeated twice within independent cDNA sets. Moreover, two different sets of primers (CRTC1-qPCR1 and CRTC1-qPCR2) were used to increase the reliability of the experiment (Additional file 2: Table S2). A 1.54-fold decrease in CRTC1 mRNA levels was observed in the hippocampus of AD cases compared to controls (p < 0.05) (Fig. 2a). Next, a disease-staging analysis was conducted to investigate changes of CRTC1 mRNA levels across AD stages. We found that CRTC1 mRNA levels significantly decreased across AD stages (p < 0.05) and post-hoc analysis showed that CRTC1 expression was significantly reduced at advanced stages compared to controls (p < 0.05) (Fig. 2b).Fig. 2


CRTC1 gene is differentially methylated in the human hippocampus in Alzheimer's disease.

Mendioroz M, Celarain N, Altuna M, Sánchez-Ruiz de Gordoa J, Zelaya MV, Roldán M, Rubio I, Larumbe R, Erro ME, Méndez I, Echávarri C - Alzheimers Res Ther (2016)

CRTC1 mRNA expression is decreased in human hippocampus in Alzheimer’s disease (AD). a The graph shows a significant 1.54-fold decrease in CRTC1 mRNA levels in AD hippocampal samples compared to control hippocampal samples. bCRTC1 mRNA expression decreases across AD stages, as shown when CRTC1 expression levels are sorted based on ABC score. Boxes represent percentage of CRTC1 expression relative to the geometric mean of GAPDH and ACTB housekeeping genes expression. Bars represent the standard error of the mean. *p-value < 0.05; ** p-value < 0.005. c Two different CRTC1 transcript variants are shown. CRTC1 variant 1 has 14 exons and CRTC1 variant 3 shares all the exons of variant 1 plus an additional exon 3. Black boxes represent exons, arrows represent transcription start sites and white boxes denote CpG islands. CpG cytosine-phosphate-guanine
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4837517&req=5

Fig2: CRTC1 mRNA expression is decreased in human hippocampus in Alzheimer’s disease (AD). a The graph shows a significant 1.54-fold decrease in CRTC1 mRNA levels in AD hippocampal samples compared to control hippocampal samples. bCRTC1 mRNA expression decreases across AD stages, as shown when CRTC1 expression levels are sorted based on ABC score. Boxes represent percentage of CRTC1 expression relative to the geometric mean of GAPDH and ACTB housekeeping genes expression. Bars represent the standard error of the mean. *p-value < 0.05; ** p-value < 0.005. c Two different CRTC1 transcript variants are shown. CRTC1 variant 1 has 14 exons and CRTC1 variant 3 shares all the exons of variant 1 plus an additional exon 3. Black boxes represent exons, arrows represent transcription start sites and white boxes denote CpG islands. CpG cytosine-phosphate-guanine
Mentions: To test if CRTC1 was differentially expressed in our cohort, we measured CRTC1 mRNA expression levels by RT-qPCR in hippocampal samples from Alzheimer’s disease (AD) cases and controls. Four samples did not pass the RNA quality threshold and so were not included in the experiments (see CRTC1 mRNA expression analysis in the Methods section). Eventually, 26 AD cases were compared to 12 controls. RT-qPCR reactions were performed in triplicate for each sample and repeated twice within independent cDNA sets. Moreover, two different sets of primers (CRTC1-qPCR1 and CRTC1-qPCR2) were used to increase the reliability of the experiment (Additional file 2: Table S2). A 1.54-fold decrease in CRTC1 mRNA levels was observed in the hippocampus of AD cases compared to controls (p < 0.05) (Fig. 2a). Next, a disease-staging analysis was conducted to investigate changes of CRTC1 mRNA levels across AD stages. We found that CRTC1 mRNA levels significantly decreased across AD stages (p < 0.05) and post-hoc analysis showed that CRTC1 expression was significantly reduced at advanced stages compared to controls (p < 0.05) (Fig. 2b).Fig. 2

Bottom Line: Moreover, a 1.54-fold decrease in CRTC1 mRNA levels was observed in hippocampus of AD cases compared to controls (p < 0.05) supporting the notion that CRTC1 is downregulated in the AD hippocampus.DNA methylation levels within two distinct promoter regions of the CRTC1 gene were decreased in human hippocampus affected by AD compared with controls and methylation within Prom1 showed a strong inverse correlation with p-tau deposition.Further studies are guaranteed to elucidate the precise role that CRTC1 methylation plays in AD pathophysiology.

View Article: PubMed Central - PubMed

Affiliation: NeuroEpigenetics Laboratory, Navarrabiomed- IdiSNA (Navarra Institute for Health Research), c/ Irunlarrea, 3, Pamplona, Navarra, 31008, Spain. maitemendilab@gmail.com.

ABSTRACT

Background: CRTC1 (CREB regulated transcription coactivator 1) gene plays a role in synaptic plasticity, learning and long-term memory formation in the hippocampus. Recently, CRTC1 has been shown to be downregulated in Alzheimer's disease (AD). Nevertheless, the mechanisms underlying CRTC1 dysregulation in AD remain unclear.

Methods: To understand better the epigenetic mechanisms regulating CRTC1 expression that may be altered in AD, we profiled DNA methylation at CpG site resolution by bisulfite cloning sequencing in two promoter regions (referred to as Prom1 and Prom2) of the CRTC1 gene in human hippocampus from controls and AD cases. Next, we correlated DNA methylation levels with AD-related pathology, i.e., β-amyloid and phosphorylated-tau (p-tau) burden and also measured CRTC1 mRNA levels by RT-qPCR.

Results: Methylation levels were lower in AD cases as compared to controls within both promoter regions (Prom1: 0.95% vs. 5%, p-value < 0.01 and Prom2: 2.80% vs. 17.80%, p-value < 0.001). Interestingly, CRTC1 methylation levels inversely correlated with AD-related neuropathological changes, particularly with p-tau deposition (rSpearman = -0.903, p < 0.001). Moreover, a 1.54-fold decrease in CRTC1 mRNA levels was observed in hippocampus of AD cases compared to controls (p < 0.05) supporting the notion that CRTC1 is downregulated in the AD hippocampus.

Conclusions: DNA methylation levels within two distinct promoter regions of the CRTC1 gene were decreased in human hippocampus affected by AD compared with controls and methylation within Prom1 showed a strong inverse correlation with p-tau deposition. Further studies are guaranteed to elucidate the precise role that CRTC1 methylation plays in AD pathophysiology.

No MeSH data available.


Related in: MedlinePlus