Alzheimer’s Disease (AD) is the most common cause of dementia in the elderly. Centenarians – reaching the age of >100 years while maintaining good cognitive skills – seemingly have unique biological features allowing healthy aging and protection from dementia. Here, we studied the expression of SIRT1 along with miR-132 and miR-212, two microRNAs known to regulate SIRT1, in lymphoblastoid cell lines (LCLs) from 45 healthy donors aged 21 to 105 years and 24 AD patients, and in postmortem olfactory bulb and hippocampus tissues from 14 AD patients and 20 age-matched non-demented individuals. We observed 4.0-fold (P = 0.001) lower expression of SIRT1, and correspondingly higher expression of miR-132 (1.7-fold; P = 0.014) and miR-212 (2.1-fold; P = 0.036), in LCLs from AD patients compared with age-matched healthy controls. Additionally, SIRT1 expression was 2.2-fold (P = 0.001) higher in centenarian LCLs compared with LCLs from individuals aged 56–82 years; while centenarian LCLs miR-132 and miR-212 indicated 7.6-fold and 4.1-fold lower expression, respectively. Correlations of SIRT1, miR-132 and miR-212 expression with cognitive scores were observed for AD patient-derived LCLs and postmortem AD olfactory bulb and hippocampus tissues, suggesting that higher SIRT1 expression, possibly mediated by lower miR-132 and miR-212, may protect aged individuals from dementia and is reflected in their peripheral tissues.
Bipolar disorder (BD) and cluster headache (CH) are distinct conditions with important similarities such as a temporal pattern of disturbances, dysregulation of the sleep-wake cycle, and response to lithium treatment in a proportion of patients. Aiming to identify common transcription signatures in these two disorders, we carried out an exploratory microarray gene expression analysis in lymphoblasts from 8 CH and 10 BD I patients selected for positive response to lithium and 10 healthy controls (CO). Gene expression levels of BD and CH were compared with CO to create two lists of differentially expressed genes. We then matched the two lists and focus on genes showing statistically significant difference and same change direction in both disorders. RNA binding motif protein 3 (RBM3) was the most significantly altered gene in the list (3.17 × 10(-13) in BD, 9.44 × 10(-14) in CH). Pathway analysis identified protein processing in endoplasmic reticulum as the most significantly enriched. For validation with quantitative reverse transcription PCR (qRT-PCR) using the same samples, we selected seven genes. Among these, we were able to validate the RBM3, nuclear receptor subfamily 1, group D, member 1 (NR1D1), and tryptophan hydroxylase 1 (TPH1). These genes encode for elements involved in circadian rhythm regulation (RBM3 and NR1D1) and in serotonin synthesis (TPH1), processes previously involved in both disorders, and in the mechanism of action of lithium.
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