FANTASTIC STEM CELLS and Where to Find Them with Shiri Gur-Cohen

Assistant Professor Sherry introduces the concept of stem cells and their ability to regenerate tissues. She suggests the possibility of tricking stem cells into acting young, thus maintaining health and vitality as we age. Sherry explains that our body has a remarkable regenerative capacity, with cells constantly being replaced, from the rapidly renewing intestine and skin to the slower-turning muscles and non-renewing heart in adults. Stem cells are key to this process, responding quickly to injuries and maintaining tissue turnover. However, as we age, this process becomes less efficient, leading to slower healing and other age-related issues. Sherry's research aims to understand what keeps stem cells youthful and how to leverage this knowledge to develop new technologies that could potentially reverse the aging process in stem cells.

The script discusses the visible signs of aging, particularly on the skin, which is the fastest-aging organ due to its constant exposure to harmful external elements like UV radiation and pathogens. It explains how the skin's regenerative capacity slows down with age, leading to less firm skin, pigment loss, slower wound healing, and the appearance of age spots. The skin's regenerative process is compared across different life stages, from babies who heal rapidly to older individuals whose skin takes increasingly longer to regenerate. The paragraph highlights the prevalence of chronic wounds, especially among the aging population, and the need for a better solution to address this issue, focusing on the potential of stem cells to improve healing and regenerate tissues.

This paragraph delves into the fascinating abilities of stem cells found in our tissues, particularly those related to skin and hair growth. It explains that these 'magical' stem cells have the capacity for self-renewal and differentiation, creating new tissue cells as needed. The balance between stem cell self-renewal and differentiation is crucial to avoid insufficient tissue growth or cancer. The speaker, a stem cell biologist and microscopist, is intrigued by the interaction between stem cells and their environment, especially how stem cells communicate with their surroundings during regeneration. The skin is highlighted as a unique organ housing multiple types of stem cells, including epidermal and melanocyte stem cells, which are responsible for skin and hair color, respectively.

The script explores the connection between the lymphatic system and stem cell regeneration, focusing on the hair follicle as an example. It describes how hair follicle stem cells can change their fate to regenerate skin when wounds occur, demonstrating their adaptability. The paragraph discusses the cyclic nature of hair growth and how this process is affected by systemic changes such as aging, hormonal cues, and stress. The lymphatic system's role in maintaining the youth and functionality of stem cells is introduced, with the hypothesis that the lymphatic system may coordinate regenerative processes and influence stem cell behavior.

The speaker describes the innovative use of microscopy to study the relationship between stem cells and the lymphatic system in three dimensions. By making the skin transparent, researchers can visualize the complex architecture of blood and lymphatic vessels in relation to stem cells. The lymphatic capillaries are shown to create protrusions that hold stem cells tightly during their resting phase, and this interaction is controlled by the stem cells themselves. The speaker emphasizes the importance of this discovery in understanding how stem cells maintain their regenerative potential and how their environment, or niche, supports this process.

This paragraph investigates the reasons behind hair loss as we age, questioning whether it is due to the loss of stem cells or a deterioration of their supportive environment. The speaker discusses the similarities between young and old stem cells, noting that while the old stem cells still express the same genes as the young ones, they fail to perform their regenerative functions effectively. The importance of the structure and environment of stem cells, known as the niche, is highlighted, particularly the role of lymphatic vessels in maintaining this structure. The speaker suggests that the disruption of this structure and the decline in the function of lymphatic vessels may contribute to the aging process and the inability of stem cells to regenerate tissues effectively.

The script presents an experiment that explores the potential to reverse the aging process in stem cells. By isolating stem cells and their environments from both young and old mice, the researchers discovered that young stem cells placed in an aged environment lost their regenerative capabilities. In contrast, old stem cells placed in a young environment were 'tricked' into behaving as if they were young, regenerating hair as they would have in their prime. This finding suggests that the environment surrounding stem cells, particularly the lymphatic system, plays a crucial role in their aging and regenerative abilities. The potential for the lymphatic system to renew stem cells in various tissues is also discussed, hinting at a possible central cause for stem cell aging and the potential for reversing it.

The final paragraph outlines the speaker's ongoing research in the laboratory, focusing on how epithelial stem cells communicate with their environment to maintain dynamic tissue modeling. The speaker expresses gratitude to mentors, colleagues, and funding sources for their support in this endeavor. The research aims to leverage the knowledge gained from studying stem cell interactions with their lymphatic micro-environment to develop new technologies that could restore and rejuvenate stem cells, potentially extending healthspan and lifespan. The speaker concludes by emphasizing the importance of this research in not only improving skin texture but also in the broader goal of tissue regeneration.