4月1日,从遗传学角度研究衰老机制的一组英国科学家在《公共科学图书馆·综合》（PLoS ONE）网站撰文指出，他们针对实验室蠕虫进行的研究表明，DAF-16基因同寿命、免疫力密切相关。由于很多动物和人体内都拥有DAF-16基因，该发现有助于更好地了解影响人类衰老和免疫功能的原因。
全球各地的人们正在大踏步迈向衰老，给健康和社会保障体系提出了巨大挑战。丹麦科学家去年进行的一项研究发现，富裕国家出生的婴儿中，有一半将可以庆祝其百岁诞辰。科学家急切渴望能够找到令人衰老的原因，据此研发出药物帮助人们尽可能长寿，并在有生之年保持健康。
英国伯明翰大学的罗宾·梅尔领导了这项研究。梅尔团队比较了4种关系密切的蠕虫的寿命、抗药性以及免疫力情况，他们发现，这4种蠕虫体内的DAF-16基因的活性存在巨大的差异。
更重要的是，DAF-16活性的差异同寿命、抵抗力和免疫力相辅相成：DAF-16的活性越高，蠕虫的寿命越长，抗感染的免疫力越好。梅尔表示，这表明，免疫力和衰老密切相关。物种之间的DAF-16基因的活性的差异对衰老和健康具有非常重要的影响，这或许可以解释人与人之间的寿命为何不同。
梅尔称，DAF-16在体内大多数细胞中都很活跃，它们同人体内的FoxO家族调节基因非常类似，科学家认为FOXO家族在动物细胞的分化、生长、增殖、代谢、免疫及衰老调节方面具有多样性功能。
英国生物技术和生物科学研究协会负责人道格拉斯·凯尔表示，这个发现将帮助科学家理解决定人类衰老的相关机制。(生物谷Bioon.com)
更多阅读
JAMA：长寿基因CETP与脑功能衰退有关
Science：敲除一种激酶基因限制热量摄入可延长寿命
PNAS：FOXO3A基因变异的人更加长寿
生物谷推荐原文出处：
PLoS ONE doi:10.1371/journal.pone.0009978
Phenotypic Covariance of Longevity, Immunity and Stress Resistance in the Caenorhabditis Nematodes
Francis R. G. Amrit, Claudia M. L. Boehnisch, Robin C. May*
Background
Ageing, immunity and stresstolerance are inherent characteristics of all organisms. In animals, these traits are regulated, at least in part, by forkhead transcription factors in response to upstream signals from the Insulin/Insulin–like growth factor signalling (IIS) pathway. In the nematode Caenorhabditis elegans, these phenotypes are molecularly linked such that activation of the forkhead transcription factor DAF-16 both extends lifespan and simultaneously increases immunity and stress resistance. It is known that lifespan varies significantly among the Caenorhabditis species but, although DAF-16 signalling is highly conserved, it is unclear whether this phenotypic linkage occurs in other species. Here we investigate this phenotypic covariance by comparing longevity, stress resistance and immunity in four Caenorhabditis species.
Methodology/Principal Findings
We show using phenotypic analysis of DAF-16 influenced phenotypes that among four closely related Caenorhabditis nematodes, the gonochoristic species (Caenorhabditis remanei and Caenorhabditis brenneri) have diverged significantly with a longer lifespan, improved stress resistance and higher immunity than the hermaphroditic species (C. elegans and Caenorhabditis briggsae). Interestingly, we also observe significant differences in expression levels between the daf-16 homologues in these species using Real-Time PCR, which positively correlate with the observed phenotypes. Finally, we provide additional evidence in support of a role for DAF-16 in regulating phenotypic coupling by using a combination of wildtype isolates, constitutively active daf-16 mutants and bioinformatic analysis.
Conclusions
The gonochoristic species display a significantly longer lifespan (p<0.0001) and more robust immune and stress response (p<0.0001, thermal stress; p<0.01, heavy metal stress; p<0.0001, pathogenic stress) than the hermaphroditic species. Our data suggests that divergence in DAF-16 mediated phenotypes may underlie many of the differences observed between these four species of Caenorhabditis nematodes. These findings are further supported by the correlative higher daf-16 expression levels among the gonochoristic species and significantly higher lifespan, immunity and stress tolerance in the constitutively active daf-16 hermaphroditic mutants。
