Unraveling the interplay between metabolism, epigenetics and stem cell fate in the hair follicle

项目总结 新的证据揭示了干细胞(SCs)自我平衡对细胞新陈代谢的关键作用 更新和分化，以维持组织的动态平衡。然而，从机制上讲，人们对此知之甚少。 干细胞在决定细胞命运的过程中将代谢刺激整合到它们体内的利基环境中。此外，还有几个 代谢物的种类越来越被认为能够影响表观遗传过程，控制 染色质重塑，包括高度可塑性的染色质结构域，引导关键的转录程序 维护SC身份。因此，为了更好地理解新陈代谢之间的复杂串扰， 表观遗传学和SC功能对于确定必要的信号级联是关键的，以保存SC- 调节的再生能力。为了实现这些目标，小鼠毛囊是一个很好的系统 因为它自然会经历组织动态平衡和再生的周期性和同步循环。 首先，我将分离和纯化静止期、激活期和激活期的毛囊干细胞(Hfscs)。 在他们向短暂的、增殖性的祖细胞过渡之后。然后我将在体内进行代谢组学分析 用气相色谱-质谱法直接测定代谢物丰度。稳定同位素 追踪将确定代谢物周转率及其来自几种碳源的相对贡献， 包括葡萄糖、脂肪酸和氨基酸谷氨酰胺(目标I)。接下来，我将设计生物能量学 在毛发周期和体内生理状态下监测hfSCs代谢动态的传感器 布景。这将通过利用我的实验室强大而快速的宫内慢病毒技术来实现 将这些传感器专门输送到皮肤上皮和毛囊(AIM II)。我将应用CRISPR调解 利用宫内慢病毒传递平台对代谢的影响进行功能性评估的基因敲除策略 对hfSCs代谢和行为的扰动。最后，我将衡量这些措施的影响 针对hfSCs染色质重塑的关键代谢途径的干预，澄清 代谢适应在控制转换的表观遗传转换中所起的机械作用 从自我更新到世系承诺和差异化(目标III)。总之，这项工作将定义功能 再生毛发代谢重编程的后果和表观遗传学机制 卵泡，提供新的治疗靶点，有可能帮助维持长期组织 受SC失衡影响的疾病的动态平衡，从衰老到癌症。

PROJECT SUMMARY Emerging evidence has uncovered a critical role for cellular metabolism as stem cells (SCs) balance self- renewal and differentiation to maintain tissue homeostasis. However, little is known mechanistically about how SCs integrate metabolic stimuli during cell fate decisions within their in vivo niches. Furthermore, several classes of metabolites are increasingly being recognized as able to influence epigenetic processes that control chromatin remodeling, including highly plastic chromatin domains that direct key transcriptional programs to maintain SC identity. Thus, achieving a better understanding of the complex crosstalk between metabolism, epigenetics and SC function is critical to identify essential signaling cascades necessary to preserve SC- mediated regenerative capacity. To achieve these goals, the murine hair follicle is an excellent system because it naturally undergoes recurrent and synchronous cycles of tissue homeostasis and regeneration. First, I will isolate and purify populations of hair follicle stem cells (HFSCs) during quiescence, activation and following their transition to short-lived, proliferative progenitors. I will then perform in vivo metabolomic profiling by directly measuring metabolite abundance using gas chromatography–mass spectrometry. Stable isotope tracing will determine metabolite turnover rates and their relative contributions from several carbon sources, including glucose sugars, fatty acids and the amino acid glutamine (Aim I). Next, I will engineer bioenergetic sensors to monitor the metabolic dynamics of HFSCs throughout the hair cycle and within in vivo physiological setting. This will be accomplished by exploiting my lab's powerful and rapid in utero lentiviral technology to deliver these sensors specifically to the skin epithelium and hair follicle (Aim II). I will apply CRISPR-mediated knockout strategies using the in utero lentiviral delivery platform to functionally assess the impact of metabolic perturbations to the metabolism and behavior of HFSCs. And finally, I will measure the impact of these interventions aimed at critical metabolic pathways on chromatin remodeling in HFSCs, clarifying the mechanistic contributions played by metabolic adaptations during the epigenetic switch governing the transition from self-renewal to lineage commitment and differentiation (Aim III). In total, this work will define the functional consequences and epigenetic mechanisms underlying metabolic reprogramming in the regenerating hair follicle, providing novel therapeutic targets that have the potential to help maintain long-term tissue homeostasis in diseases affected by SC imbalance, ranging from aging to cancer.