头发变白是衰老的标志,通常被认为是不可逆转的,并与心理压力有关。
这里,我们开发了一种沿着个人毛干描绘毛发色素沉着模式(HPP)的方法,产生可量化的快速灰化过渡的物理时间尺度。
使用此方法,我们显示白色/灰色的头发自然恢复性别的色素沉着,种族,年龄,和身体区域,从而定量地定义了人类变灰的可逆性。分子上,白发上调与能量代谢相关的蛋白质,线粒体,和抗氧化防御。在单根毛发上结合HPP分析和蛋白质组学,我们还报告了头发变白和逆转可能与心理压力源同时发生。为了概括这些观察结果,我们开发了一个计算模拟,这提出了一种基于阈值的机制,用于灰色的暂时可逆性。
总的来说,这种定量绘制HPP中最近生活史的新方法提供了一个纵向检查最近生活暴露对人类生物学影响的机会.
这项工作得到了沃顿基金和NIHGM119793,MH119336和AG066828(MP)的资助。
头发变白是影响每个人的衰老的明显迹象。头发颜色的损失是由于黑色素的损失,一种在皮肤上发现的色素,眼睛和头发对老鼠的研究表明,压力可能会加速头发变白,但是在人类中没有明确的研究。这是因为没有研究工具可以随着时间的推移精确映射应力和头发颜色。但是,就像树木年轮保存着过去几十年的信息一样,岩石保存着过去几个世纪的信息,头发保存着过去几个月和几年的信息。毛发生长是一个活跃的过程,发生在毛囊内的皮肤下。它需要大量的能量,由细胞内称为线粒体的结构提供。当头发生长时,细胞从体内接收化学和电信号,包括压力荷尔蒙.这些暴露可能会改变生长在毛干中的蛋白质和其他分子。当头发从头皮上长出来时,它变硬了,将这些分子保存为稳定的形式。这种保存作为色素沉着的模式是可见的。检查单发并将模式与生活事件相匹配,可以让研究人员回顾一个人的生物历史。罗森伯格等人。报告一种数字化和测量人类单发颜色微小变化的新方法。这种方法表明,一些白发自然恢复了颜色,以前在健康个体队列中没有报道过的东西。将头发色素沉着模式与最近有关头发捐赠者生活压力的报道保持一致,显示出惊人的关联。当一个捐赠者报告压力增加时,一根头发失去了色素。当捐赠者报告压力减轻时,同样的头发恢复了色素。罗森伯格等人。绘制了毛发内部的数百种蛋白质,表明白色毛发含有更多与线粒体和能量使用相关的蛋白质。这表明新陈代谢和线粒体可能在头发变白中起作用。更详细地探讨这些观察结果,Rosenberg等人。开发了一个数学模型,模拟整个头发在一生中变白的过程,一个不可能与活人有关的实验。该模型表明,可能存在暂时变白的阈值;如果头发无论如何都要变白,压力事件可能会更早触发这种变化。当紧张的事件结束时,如果一根头发刚刚超过门槛,然后它可以恢复到黑暗。测量毛发着色的微小变化的新方法开辟了使用毛发色素沉着图案如树年轮的可能性。这可以追踪过去生活事件对人类生物学的影响。在未来,监测头发色素沉着模式可以提供一种追踪旨在减轻压力或减缓衰老过程的治疗效果的方法。了解“老”白发如何恢复其“年轻”的色素状态,也可以揭示有关人类衰老的延展性的新信息。
Hair greying is a hallmark of aging generally believed to be irreversible and linked to psychological stress.
Here, we develop an approach to profile hair pigmentation patterns (HPPs) along individual human hair shafts, producing quantifiable physical timescales of rapid greying transitions.
Using this method, we show white/grey hairs that naturally regain pigmentation across sex, ethnicities, ages, and body regions, thereby quantitatively defining the reversibility of greying in humans. Molecularly, grey hairs upregulate proteins related to energy metabolism, mitochondria, and antioxidant defenses. Combining HPP profiling and proteomics on single hairs, we also report hair greying and reversal that can occur in parallel with psychological stressors. To generalize these observations, we develop a computational simulation, which suggests a threshold-based mechanism for the temporary reversibility of greying.
Overall, this new method to quantitatively map recent life history in HPPs provides an opportunity to longitudinally examine the influence of recent life exposures on human biology.
This work was supported by the Wharton Fund and NIH grants GM119793, MH119336, and AG066828 (MP).
Hair greying is a visible sign of aging that affects everyone. The loss of hair color is due to the loss of melanin, a pigment found in the skin, eyes and hair. Research in mice suggests stress may accelerate hair greying, but there is no definitive research on this in humans. This is because there are no research tools to precisely map stress and hair color over time. But, just like tree rings hold information about past decades, and rocks hold information about past centuries, hairs hold information about past months and years. Hair growth is an active process that happens under the skin inside hair follicles. It demands lots of energy, supplied by structures inside cells called mitochondria. While hairs are growing, cells receive chemical and electrical signals from inside the body, including stress hormones. It is possible that these exposures change proteins and other molecules laid down in the growing hair shaft. As the hair grows out of the scalp, it hardens, preserving these molecules into a stable form. This preservation is visible as patterns of pigmentation. Examining single-hairs and matching the patterns to life events could allow researchers to look back in time through a person’s biological history. Rosenberg et al. report a new way to digitize and measure small changes in color along single human hairs. This method revealed that some white hairs naturally regain their color, something that had not been reported in a cohort of healthy individuals before. Aligning the hair pigmentation patterns with recent reports of stress in the hair donors’ lives showed striking associations. When one donor reported an increase in stress, a hair lost its pigment. When the donor reported a reduction in stress, the same hair regained its pigment. Rosenberg et al. mapped hundreds of proteins inside the hairs to show that white hairs contained more proteins linked to mitochondria and energy use. This suggests that metabolism and mitochondria may play a role in hair greying. To explore these observations in more detail Rosenberg et al. developed a mathematical model that simulates the greying of a whole head of hair over a lifetime, an experiment impossible to do with living people. The model suggested that there might be a threshold for temporary greying; if hairs are about to go grey anyway, a stressful event might trigger that change earlier. And when the stressful event ends, if a hair is just above the threshold, then it could revert back to dark. The new method for measuring small changes in hair coloring opens up the possibility of using hair pigmentation patterns like tree rings. This could track the influence of past life events on human biology. In the future, monitoring hair pigmentation patterns could provide a way to trace the effectiveness of treatments aimed at reducing stress or slowing the aging process. Understanding how ‘old’ white hairs regain their ‘young’ pigmented state could also reveal new information about the malleability of human aging more generally.