Abstract:
The use of the laboratory rat (Rattus norvegicus) has been critical for biological research in diverse fields such as
physiology, pharmacology, cell biology, immunology, toxicology, nutrition, and behavior. Furthermore, it is the
preferred species for disease modeling and as a platform for the development of novel therapeutics. Of the many
rat strains, Sprague Dawley (SD), Lewis (LEW/SsNHsd), Long-Evans, Fisher 344 (F344), and immunodeficient
athymic nude (Hsd:RH-Foxn1rnu ) rats are the most popular ones for biological studies. In 2008, three groups
established chimera- and/or germline-competent rat embryonic stem cells (rESCs). In addition, based on the
ground-breaking work by Yamanaka and colleagues to reprogram somatic tissues to ESC-like induced
pluripotent stem cells, several groups including ours reported on the generation of rat induced pluripotent stem
cells (riPSCs) from SD somatic tissues. While this iPSC technology has been revolutionizing biomedical
research and the study of regenerative medicine, it is still in its early stage (a decade-old) and significant efforts
are required to improve our understanding of reprogramming and to advance its technology. For instance, it is
well documented that individual human ESC and iPSC lines exhibit remarkably different propensities in their
differentiation properties and that iPSC lines retain certain level of “epigenetic memory”, directly affecting
differentiation properties. At present, comparative analyses of genomic, epigenomic, transcriptomic, metabolic,
and differentiation properties of riPSCs from diverse rat strains are lacking. Our multidisciplinary team proposes
the following 4 Specific Aims over the next 4 years: Aim 1: Generation and characterization of multiple riPSC
lines from three popular tissues of SD rats: rat embryonic fibroblasts, neural precursor cells and peripheral blood
mononuclear cells using conventional and our novel reprogramming methods. Aim 2: Global genomic,
epigenomic, and transcriptomic status using state-of-the-art methods. Aim 3: Establish authentic riPSC lines
from Lewis, Long-Evans, F344, and athymic rats using our novel and optimized reprogramming methods. All
genomic data for each riPSC line will be shared with academic community. Aim 4: Assessment of the
immunogenicity of riPSC-derived tissues in syngeneic and allogeneic hosts using in vitro analyses and in vivo
transplantation studies. In summary, this R24 will establish well-validated and viable riPSC lines along with their
comprehensive biological and genomic characteristics.