Muscle Stem Cell Renewal in a Bioengineered Regenerative Niche
One big problem with stem cell therapies is that when the stem cells are transplanted, injected or otherwise administered to the patient, most of those cells simply die. The reasons they die are still not quite understood, but it seems they suffer a "culture shock" from their new environment. Remember that most therapeutic cells are grown in a lab on a plastic surface in a chemical nutrient medium, which certainly is not the same as in whatever tissue they are destined to try to repair. To a stem cell, this environment is its niche, just as an animal fits into its ecological niche. A big current gap in the utility of stem cell therapy is coordinating the therapeutic cell with a stem cell niche.
In order to better prepare the therapeutic stem cell in the lab for its ultimate home in the body, we have recently reverse-engineered the muscle regenerative stem cell niche. We form a 3 dimensional, biochemically defined matrix and infuse that with biochemically defined growth and differentiation factors. In our niche, both mouse and human adult muscle cells self-assemble into muscle fibers, while some cells de-differentiate into myofiber-associated muscle stem cells.
This project first will begin to translate our results from mouse muscle to human cells, demonstrate that these cells are functional in the niche, and then investigate how this niche works on the molecular level to instruct cells.
1. To determine if human muscle cells in the bioengineered niche make functional muscle in mice, with associated, functional, renewed muscle stem cells.
2. To determine if human healthy muscle cells, marked with the firefly luciferase gene will grow in and repair muscle in mice with muscular dystrophy, by imaging the glowing muscle in live mice using the Xenogen camera.
3. To define the molecular mechanisms by which the engineered niche is appropriate for muscle stem cells. We will focus on telomerase activity and signaling pathways that we have found important in regenerating muscle, comparing among the cells in the bioengineered niche, native regenerating muscle cells and cultured muscle cells.
Significance: These experiments will uncover the properties of how the stem cell interacts with the niche, especially in muscle. This work translates our powerful findings in mouse to a human cell model, taking steps toward a long sought-after therapy for genetic/acquired myopathies, such as Duchenne Muscular Dystrophy, where traditional myoblast transplantation has failed due to massive cell death, poor engraftment and lack of self-renewal, and where traditional muscle stem cell transplantation is not practical since these cells do not grow well in the lab.
This research proposed herein benefits Californians, California as a society and the State of California. As it is applicable to all of humanity, Californians will ultimately see medical benefits from this basic research on the stem cell niche in muscle: improvements to their musculo-skeletal health and quality of life, a longer productive lifespan and enjoyment from a more active lifestyle. Californians suffering muscular dystrophies will benefit even sooner as this class of diseases will be targeted first.
California as a society benefits from the aggregate medical benefits above, plus the economic benefits from fostering cutting edge research in the state at [REDACTED]. This proposal seeks to improve stem cell responses in the old and to rescue tissue repair in people suffering from debilitating degenerative diseases. The accumulated life-long skills, expertise and invaluable knowledge older or infirm Californians have to contribute will not be lost to our society as rapidly since we will be healthier and more able later in life. That this work is conducted in California benefits our local academic and high-tech cultures and economy. Qualified scientists from underrepresented minorities will be involved with this translational research, expanding the education and representation of all Californians in the cutting-edge biomedical research. That most of the research dollars are spent here in California puts more qualified people at work and boosts the living standard for all Californians. In the longer term, this research also reduces the health-costs associated with treating currently incurable degenerative diseases.
The great state of California ultimately benefits from this work, in the short term at [REDACTED] and in the longer term through the enduring legacy of CIRM. The success of this project adds some small measure to the prestige of [REDACTED]. Success, with time, will justify CIRM’s mission of independent state sponsored biomedical research and lend support to future institutes of its kind.