Functional Genomic Study of Aging and Aging Interventions

衰老的特征是各种生理功能的逐渐衰退，并与包括蛋白质、脂肪和核酸在内的大分子的大量损伤和修饰有关。准确和灵敏的蛋白质修饰测量，如糖基化和磷酸化，对于我们理解衰老过程至关重要。为此，我们与国家老龄研究所(NIA)内外的几个实验室合作，开发出对老龄化研究有价值的量化工具。我们与密西西比州立大学的张东茂博士合作，发表了两种量化方法。一种是使用可酸裂解的表面增强拉曼光谱(SERS)标签来量化蛋白质和蛋白质修饰的水平。我们的方法显著提高了基于荧光的蛋白质检测的灵敏度和准确性。这项研究发表在《分析家》(2011)上。另一种方法是使用罗丹明B衍生物作为表面增强拉曼光谱(SERS)标签来检测碳水化合物。后一种方法可以用来测量衰老过程中的蛋白质糖基化，这仍然是相当难以捉摸的。这项工作已发表在《分析化学》(2010)上。我们与NIA的沈荣芳、Bronwen Martin和Stuart Maudsley博士合作，系统地评价了脉冲Q碰撞诱导解离(PQD)方法在蛋白质组学研究中用于肽鉴定的方法。在使用LTQ质谱仪进行多肽定量时，通常采用PQD方法来检测低质量报告离子。在蛋白质组学研究中，对PQD方法的优化对于鉴定具有不稳定官能团的多肽(如磷酸肽)特别有价值。这项工作已被接受发表在《美国质谱学学会杂志》(2011年出版)上。 为了了解衰老的基本生物学过程，我们鉴定了一个与哺乳动物基因Aven高度同源的苍蝇基因。哺乳动物Aven是DNA损伤反应和G2/M细胞周期进程的调节者，与几种类型的癌症有关，如急性髓系白血病。我们发现，果蝇Aven(Daven)是苍蝇脂肪组织中正常细胞周期发展所必需的。这项研究已发表在《细胞周期》(2011)上。未来的研究将致力于了解Daven在DNA损伤反应中的作用，这将揭示可能与癌症和衰老相关的信息。综上所述，我们从这项研究中的发现以及上述分析工具为我们进一步研究衰老过程中的分子变化以及这些变化对寿命和健康寿命的影响提供了基础。 许多植物，包括水果和蔬菜，由于其高抗氧化能力和多种生物活性，是延长寿命和健康寿命的理想选择。然而，鲜为人知的植物药具有延年益寿的功效。实施老龄化干预的有效方法仍然知之甚少。我们之前已经证明，补充水果提取物与蔓越莓和牛至提取物混合可以促进墨西哥果蝇的寿命和繁殖能力。为了进一步研究小红莓的健康益处，我们评估了长期食用小红莓对大鼠胰腺年龄相关变化的影响。我们发现，长期食用小红莓可以防止基础胰岛素释放的年龄相关下降，改善细胞葡萄糖反应，并维持正常衰老大鼠的功能性细胞质量。我们的研究结果表明，食用小红莓对糖尿病患者是有益的。这项工作已发表在《老年学杂志》系列A：生物科学(2011)上。为了进一步了解水果和草药调节寿命的分子机制，我们以黑腹果蝇为模型系统。我们已经确定了油桃，一种全球消费的水果，对黑腹果蝇寿命和健康寿命的影响。我们的发现表明，油桃至少在一定程度上通过调节葡萄糖代谢和减少氧化损伤来延长寿命和健康寿命。这项研究首次证明了油桃的延年益寿作用，并发表在《自由基生物学与医学》(2011)上。这些发现鼓励我们进一步研究各种植物提取物的健康益处和与衰老有关的潜在机制。这也将为水果和草药的消费提供科学指导。 总之，我们开发了分析工具，用于准确和可靠地测量蛋白质和蛋白质修饰，适用于研究老化过程中的分子变化。此外，我们还展示了两种植物提取物，蔓越莓和油桃提取物，分别在促进大鼠和苍蝇的健康和长寿方面的效果。这些研究应该被证明对推进实验老年学实验室的目标和NIA了解衰老的基础生物学和开发有效的衰老干预措施的使命是有价值的。该项目将为人类衰老的基本生物学提供洞察力，并促进为人类制定有效的衰老干预策略。

Aging is characterized as a gradual decline of various physiological functions and is associated with numerous damage and modifications to macromolecules, including protein, lipid and nucleic acid. Accurate and sensitive measurements of protein modifications, such as glycosylation and phosphorylation, are critical for us to understand the aging processes. To this end, we have collaborated with several laboratories in and outside of the National Institute on Aging (NIA) to develop quantitative tools valuable for aging research. In collaboration with Dr. Dongmao Zhang at the Mississippi State University, we published two quantification methods. One is to use an acid cleavable surface enhanced Raman spectroscopy (SERS) tag to quantify the levels of protein and protein modifications. Our method significantly improves the sensitivity and accuracy of fluorescence based protein detection. This work was published in The Analyst (2011). The other method is to detect carbohydrates using a Rhodamine B derivative as the Surface Enhancement Raman Spectroscopy (SERS) tag. The latter method can be utilized to measure protein glycosylation in aging, which remains quite elusive. This work has been published in Analytical Chemistry (2010). In collaboration with Drs. Rong-fong Shen, Bronwen Martin and Stuart Maudsley at the NIA, we have systematically evaluated the pulsed Q collision induced dissociation (PQD) method for peptide identification in proteomic studies. The PQD method is often employed to facilitate detection of low-mass reporter ions in peptide quantification using an LTQ mass spectrometer. Optimization of the PQD method is particularly valuable for identification of peptides with a labile functional group, such as phosphopeptides, in proteomic studies. This work has been accepted for publication in Journal of the American Society for Mass Spectrometry (2011, in press). To understand basic biological processes in aging, we have identified and characterized a fly gene highly homologous to the mammalian gene Aven. Mammalian Aven is a regulator of the DNA-damage response and G2/M cell cycle progression, and is linked to several types of cancer, such as acute myeloid leukemia. We have found that Drosophila Aven (dAven) is required for normal cell cycle progression in fly fat tissue. This work has been published in Cell Cycle (2011). Future studies will be directed to understand the role of dAven in DNA damage response, which should reveal information that may be relevant to cancer and aging. Taken together, our findings from this study along with analytical tools described above provide a foundation for us to further investigate molecular changes in the aging processes and consequences of these alterations on lifespan and health span. Many botanicals, including fruits and vegetables, are ideal for promoting longevity and health span due to their high antioxidant capacities and numerous bioactivities. However, few botanicals are actually known to possess prolongevity properties. The effective ways to implementing aging interventions remain poorly understood. We have previously demonstrated that supplementation of a fruit extract mixed with cranberry and oregano extracts can promote longevity and reproductive capacity in the Mexican fruit fly. To further investigate the health benefits of cranberry, we have evaluated the effect of long-term cranberry consumption on age-related changes in rat pancreas. We have found that a long-term cranberry consumption protects against an age-related decline in basal insulin release, improves β-cell glucose responsiveness and maintains functional β-cell mass in normal aging rats. Our findings suggest that cranberry consumption can be beneficial for diabetic patients. This work has been published in Journal of Gerontology Serial A: Biological Sciences (2011). To further understand the molecular mechanisms of lifespan regulation by fruits and herbs, we have employed Drosophila melanogaster as the model system. We have determined the effect of nectarine, a globally consumed fruit, on lifespan and health span in Drosophila melanogaster. Our findings suggest that nectarine promotes longevity and health span at least partly through modulating glucose metabolism and reducing oxidative damage. This work provides the first evidence showing the prolongevity effect of nectarine and has been published in Free Radical Biology & Medicine (2011). These findings encourage us to further investigate health benefits of various botanical extracts and the underlying mechanisms related to aging. This will also provide scientific guidance to consumption of fruits and herbs. In summary, we have developed analytic tools for accurate and reliable measurements of protein and protein modifications applicable for investigating molecular changes in aging. In addition, we have demonstrated the effects of two botanical extracts, cranberry and nectarine extracts, in promoting health and longevity in rats and flies, respectively. These studies should prove valuable to advance the objective of the Laboratory of Experimental Gerontology and the mission of the NIA to understand basic biology of aging and develop effect aging interventions. This project should provide insight into basic biology of human aging and facilitate developing effective aging intervention strategies for humans.