Understanding and reversing aging of muscle precursor cells
Irina M. Conboy
Department of Bioengineering, University of California-Berkeley, Berkeley, CA 94720, USA
Molecular regulation of muscle repair recapitulates the mechanisms
operating in embryonic organogenesis. Namely, the evolutionary
conserved Notch and Wingless (Wnt) molecular pathways regulate the
cell-fate determination of the stem and progenitor cells in adult
skeletal muscle regenerating after injury. Recent data strongly suggest
that the decline in regeneration-specific signaling and deteriorated
regenerative potential are not irreversible signatures of stem-cell
aging. In contrast, I found that the aged stem cell exposed to a young
systemic milieu up-regulated the regeneration-specific genes and
successfully repaired the damaged old tissues. The identification and
characterization of systemic factors, which are altered by age and
influence stem cell regenerative potential are the top priority
projects that are being pursued in my laboratory at UC Berkeley. The
candidate age-related factors that modulate the efficiency of muscle
repair via their effect on the key Delta-Notch signaling, will be
discussed. The mechanism by which the systemic milieu influences aging
and regeneration is another top research focus of my laboratory. A
perusal of the genetic aging models and recent data from my laboratory
suggest that the efficiency of DNA repair in myogenic progenitor cells
is strongly determined by the age of the systemic milieu. These data
provide a potential molecular mechanism of the dominance of the
systemic environment over the stem cell behavior.
Yet another approach pursued in my laboratory combines expertise in
stem cell biology and bioengineering with a goal to provide muscle stem
cells with a supportive microenvironment. The abilities of modified
extra-cellular matrix (ECM) gels to promote geometrically controlled
satellite cell expansion and differentiation will be presented. This
work may serve as a general model to engineer synthetic cellular niches
to optimally control and harness the regenerative potential of stem
cells.
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