Throughout this thesis, human aging and its relation to health are studied in the context of two parallel though complementary lines of research: biomarkers and genetics. The search for informative... Show moreThroughout this thesis, human aging and its relation to health are studied in the context of two parallel though complementary lines of research: biomarkers and genetics. The search for informative biomarkers of aging focuses on easy accessible and quantifiable substances of the body that can be used to predict the early signs of deteriorating health, prior to the development of overt age-related disease. The challenge in this field is to translate the molecular changes captured by omics platforms to the age-associated deterioration observed at the whole body-level. In this thesis, new integrative methodology was developed that lead to the identification of gene expression networks that serve as biomarkers for aging and mortality. The second part of this thesis is aimed at identifying genetic determinants that predispose to a decelerated rate of aging and an extension of life span. Using whole genome sequencing data created in 218 nonagenarians of the Leiden Longevity Study we observed that a long life is not necessarily hampered by potentially premalignant somatic mutations in either TET2 or DNMT3A. In addition, genetic variation at chr13q34 attenuating the thyroid function, may be beneficial at middle age, but seems to contribute causally to increased mortality above 90 years. Show less
Introduction. In a marmoset model of hypoactive female sexual function, we have shown that repeated administration of the serotonin (5-HT)-1A agonist R-(+)-8-hydroxy-2-(di-N-propylamino)tetralin (8... Show moreIntroduction. In a marmoset model of hypoactive female sexual function, we have shown that repeated administration of the serotonin (5-HT)-1A agonist R-(+)-8-hydroxy-2-(di-N-propylamino)tetralin (8-OH-DPAT) inhibits sexual receptivity in female marmoset monkeys and increases aggression toward the male pairmate. Aim. The aims of this study are to investigate gene expression changes induced by 8-OH-DPAT in laser-microdissected brain areas that regulate female sexual function and to identify genes, functional gene classes, and pathways associated with 8-OH-DPAT-mediated inhibition of female sexual receptivity. Methods. Gene expression was measured in the medial prefrontal cortex (mPFC), medial preoptic area (mPOA), cornu ammonis-1 (CA1) area of the hippocampus (CA1), and dorsal raphe nucleus (DRN) of four 8-OH-DPAT-treated (0.1mg/kg; daily administration for 16 weeks) and four vehicle-treated female marmosets using a marmoset-specific microarray (European Marmoset Microarray [EUMAMA]) and validated by real-time quantitative polymerase chain reaction (RTqPCR). Enriched functional gene classes were determined. In a parallel candidate gene approach, the expression of serotonergic candidate genes, i.e., the 5-HT1A, 5-HT2A, and 5-HT7 receptors and the 5-HT transporter (5-HTT), was measured by RTqPCR. Main Outcome Measures. The main outcome is the differential expression of genes between 8-OH-DPAT- and vehicle-treated marmosets. Results. 8-OH-DPAT affected the gene classes important to neural development (mPFC, mPOA, and DRN), neurotransmission (mPOA), energy production (mPFC and mPOA), learning and memory (CA1), and intracellular signal transduction (DRN). Oxytocin (OXT) in the mPOA and 5-HTT in the DRN were strongly increased by 8-OH-DPAT. 5-HT1A tended to increase in the mPFC, while 5-HT7 was decreased in the CA1. Conclusions. Brain region-specific alterations of gene expression regulating neural circuitries, energy demands, and learning processes are associated with 8-OH-DPAT-induced decrease in female sexual receptivity and increase in pairmate aggression. The role of OXT in the serotonergic regulation of female sexual behavior and partner interactions warrants attention in future studies. Show less
