The polymorphism of the serotonin-2A receptor T102C is associated with age

The serotonin receptor 5-HT2A modulates lifespan and protein feeding in Drosophila melanogaster

The conserved neurotransmitter serotonin has been shown to be an important modulator of lifespan in specific nutritional contexts; however, it remained unclear how serotonin signaling influences lifespan under normal conditions. Here, we show that serotonin signaling through the 5-HT2A receptor influences lifespan, behavior, and physiology in Drosophila. Loss of the 5-HT2A receptor extends lifespan and induces a resistance to changes in dietary protein that are normally detrimental to lifespan. 5-HT2A -/- null mutant flies also display decreased protein feeding and protein content in the body. Therefore, serotonin signaling through receptor 5-HT2A is likely recruited to promote motivation for protein intake, and chronic reduction of protein-drive through loss of 5-HT2A signaling leads to a lower protein set-point adaptation, which influences physiology, decreases feeding, and increases lifespan. Our findings reveal insights into the mechanisms by which organisms physiologically adapt in response to perceived inability to satisfy demand.

G protein-coupled receptors that influence lifespan of human and animal models

Humanity has always sought to live longer and for this, multiple strategies have been tried with varying results. In this sense, G protein-coupled receptors (GPCRs) may be a good option to try to prolong our life while maintaining good health since they have a substantial participation in a wide variety of processes of human pathophysiology and are one of the main therapeutic targets. In this way, we present the analysis of a series of GPCRs whose activity has been shown to affect the lifespan of animal and human models, and in which we put a special interest in describing the molecular mechanisms involved. Our compilation of data revealed that the mechanisms most involved in the role of GPCRs in lifespan are those that mimic dietary restriction, those related to insulin signaling and the AMPK and TOR pathways, and those that alter oxidative homeostasis and severe and/or chronic inflammation. We also discuss the possibility of using agonist or antagonist drugs, depending on the beneficial or harmful effects of each GPCR, in order to prolong people's lifespan and healthspan.

Association of the Serotonin 2A Receptor rs6311 Polymorphism with Diurnal Preference in Koreans

OBJECTIVE

Evidence for the association between circadian rhythm delay and depression is accumulating. Genetic studies have shown that certain polymorphisms in circadian genes are potential genetic markers of diurnal preference. Along with circadian genes, there is a growing interest in other genetic effects on circadian rhythms. This study evaluated whether the HTR2A rs6311 (-1438C/T) polymorphism is associated with diurnal preference in a Korean population.

METHODS

A total of 510 healthy subjects were included in this study. All subjects were genotyped for the HTR2A rs6311 polymorphism and they completed the Korean version of the composite scale of morningness (CSM).

RESULTS

The C allele carriers (C/C+C/T) showed significantly higher CSM scores compared to C allele non-carriers (T/T) (t=2.22, p= 0.03), suggesting the existence of a morning chronotype tendency in C allele carriers. In other words, the T/T genotype may be associated with the evening chronotype.

CONCLUSION

These results suggest that the HTR2A rs6311 polymorphism may be associated with diurnal preference in a healthy Korean population. The absence of the C allele may be responsible for the increasing susceptibility to eveningness in the Korean population. Further studies on HTR2A polymorphisms that evaluate their interactions with various candidate genes and differences in phenotypic expression of polymorphisms according to ethnic groups are warranted to fully understand their association with diurnal preference.

Association between T102C 5-HT2A receptor gene polymorphism and 5-year mortality risk among Brazilian Amazon riparian elderly population

OBJECTIVE

Serotonin (5-HT) is a pleiotropic molecule that exerts several functions on brain and peripheral tissues via different receptors. The gene for the 5-HT2A receptor shows some variations, including a T102C polymorphism, that have been associated with increased risk of neuropsychiatric and vascular disorders. However, the potential impact of 5-HT2A imbalance caused by genetic variations on the human lifespan has not yet been established.

METHODS

We performed a prospective study involving an Amazon riparian elderly free-living population in Maués City, Brazil, with a 5-year follow-up. Out of a cohort of 637 subjects selected in July, 2009, we genotyped 471 individuals, including 209 males (44.4%) and 262 females (55.6%), all averaging 72.3 ± 7.8 years of age (ranging from 60 to 100 years).

RESULTS

The T102C-SNP genotypic frequencies were 14.0% TT, 28.0% CC, and 58.0% CT. From 80 elderly individuals who died during the period investigated, we observed significantly (P = .005) higher numbers of TT carriers (27.3%) and CC carriers (21.2%), compared to heterozygous CT carriers (12.5%). Cox-regression analysis showed that association between the T102C-SNP and elderly survival was independent of age, sex, and other health variables.

CONCLUSIONS

Our findings strongly suggest that imbalance in 5-HT2A may cause significant disturbances that lead to an increased susceptibility to death for individuals who are over 60 years of age.

[Suicide in the elderly: age-related specificities?]

Suicide in the elderly raises the question of our relationship with aging and death. Suicide rate is relatively high in this group and is significantly related to depression widely under-diagnosed in the elderly. Suicidal behaviour in the elderly has clinical specificities including high intentionality and lethality, usually little personal history of suicidal behaviour and low levels of impulsivity-aggression. Suicidal vulnerability could rely on etiopathogenic mechanisms both common and different according to age; for example, a preponderance of early developmental factors and impulsivity-aggression in adolescents and young adults vs. pathological aging in older adults, but partly similar neurocognitive deficits leading individuals not to respond adequately to their environment (itself different with age). Direct comparisons between elderly and younger subjects would be required. The article concludes with a summary of the principles of recognition and management of suicide risk.

Estudo de associação entre nível de atividade física, risco cardiovascular e o polimorfismo do gene da apolipoproteína e em idosos

INTRODUÇÃO: com o envelhecimento, ocorre perda gradual do volume da massa muscular, responsável por quase toda a perda da força nos idosos. Estudos têm mostrado que a atividade física pode diminuir a morbidade por doenças cardiovasculares, acidente vascular cerebral e aumentar a autonomia e independência. OBJETIVO: analisar a associação entre nível de atividade física, risco cardiovascular e o polimorfismo do gene da Apolipoproteína E em idosos. MÉTODOS: estudo retrospectivo, observacional a partir de um banco de dados de base populacional onde foram selecionados idosos sedentários e com histórico de atividade física regular que eram portadores e não portadores do alelo e4 do gene da apolipoproteína E. Foram aplicados os seguintes questionários: (a) International Physical Activity Questionnaire (IPAC); (b) recordatório 24 horas e miniquestionário de frequência alimentar; (c) análises bioquímicas do perfil lipídico e glicêmico. RESULTADOS: 255 idosos foram investigados; destes, 51 (20%) eram homens e 204, mulheres (80%). A idade média da amostra foi de 67,8±5.9 anos de idade (mínimo 60 máximo 86 anos). A frequência dos alelos foi de: alelo e3 =0.78, e4=0.16 e e2=0.06; 45 idosos (17.6%) possuíam pelo menos um alelo e4 e eram sedentários, 31 (12.2%) possuíam pelo menos um alelo e4 e apresentava atividade física regular (ativa), 50 (19.6%) foram classificados como tendo os demais alelos da apoE (e2/e3) e ativos enquanto 129 (60.6%) eram e2/e3 e sedentários. CONCLUSÃO: a atividade física poderia ser um fator importante na atenuação dos efeitos genéticos negativos associados ao alelo e4 do polimorfismo da apoE.