Responsible Center: NASA HQ
Grant Monitor: Koniges, Ursula
Center Contact: 202-256-8786 ursula.m.koniges@nasa.gov
Unique ID: 15782
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Solicitation / Funding Source: 2021 Space Biology NNH21ZDA015N. Extended Longevity of 3D Tissues and Microphysiological Systems for Modeling of Acute and Chronic Exposures to Stressors
Grant/Contract No.: 80ARC023CA005
Project Type: Ground
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No. of PhD Candidates: 3
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Task Description: |
One of the most significant obstacles in building a long-lasting 3D tissue model is the lack of a stable functional vasculature. The blood vessels not only transport nutrients and oxygen, but also secrete important angiocrine factors to instruct organ/tissue homeostasis. The continuous regression of vasculature in current models will disrupt perfusion and lead to tissue necrosis. To tackle this challenge, various techniques have been attempted, such as improving biomaterial hydrogels and perfusion systems. These efforts are valuable to prolong the vascular life span, but only to a limited extent, and 6 months remains a far-reaching goal. Two fundamental issues preclude establishing a long-lasting vasculature in vitro: 1) intrinsic: cultured human endothelial cells (ECs) gradually lose their in vivo functions and tissue adaptability; 2) extrinsic: long-term maintenance of ECs requires serum/growth cytokines, resulting in loss of their innate angiogenic properties. Solving these fundamental issues is critical for building a stable long-lasting vasculature in vitro. Our recent advances have led to the central hypothesis that reprogramming ECs by forced expression of key factors can restore their in vivo characteristics, such as durable lumens, less dependence on serum/growth cytokines, and hemodynamic/tissue adaptability.
To study neurovascular interactions, we have developed a 3D human brain vasculature system that consists of human brain ECs, pericytes, and astrocytes. This system has interconnected open lumens and tight junctions with permeability similar to the blood brain barrier. Building on this platform, we developed a biomimetic 3D neurovascular model that can support the homeostatic balance of human neural stem cell (NSC) derived from induced pluripotent stem cells (iPSCs) for a 1 month period, including self-renewal, neuronal maturation, and NSC quiescence.
The goal of this project is to extend the lifespan of existing 3D neurovascular model from 1 to 6 months and demonstrate its utility by exposing to chronic stressors. In phase one, we will integrate the following approaches to prolong the lifespan of our current model: 1) Reprogram with key factors to rejuvenate in vivo EC functionalities and promote durable vascular lumen; 2) Optimize a serum free medium by screening small molecules critical for the stable vascular lumen; 3) Integrate technologies for prolonged culture and real-time sensing; these include fiber photometry that allows real-time recording of neuronal activity, fluorescent reporters that allow live visualization of vascular morphology, fluid flow, Ca2+ signaling, oxygen and cellular quiescence, a stable perfusion system with fluid/pressure control for prolonged culture. Combining these approaches, we will validate the stability and functionality of the neurovascular system in terms of vascular morphology, lumen interconnectivity, perfusion, permeability, and neural activity, and NSC reserves for 6 months. In phase two, we will validate the system to model chronic inflammation-mediated neurodegeneration by introducing microglia and inflammatory cytokines and validating whether this approach can faithfully replicate the immune response, neurodegeneration, and premature depletion of NSC reserves over a 6 month period.
Significance: Because a stable vasculature is critical for normal tissue function and homeostasis, the success of this project will have broad impact on building many other tissue models for prolonged culture using human cells (both male and female) – heart, kidney, muscle, cancer – to model human diseases. |