Investigation of Chimerism Difference in Mouse-Rat Interspecies Chimera PDF

Investigation of the chimerism difference between organs in mouse-rat interspecies chimera Mohd Azmie Edwin, Ayako Isotani (Laboratory of Organ Developmental Engineering, Division of Biological Science, NAIST) モド アズミ エドウィン (器 官 発 生 工 学 研 究 室) Chimerism is a condition in which a...

Investigation of the chimerism difference between organs in mouse-rat interspecies chimera Mohd Azmie Edwin, Ayako Isotani (Laboratory of Organ Developmental Engineering, Division of Biological Science, NAIST) モド アズミ エドウィン (器 官 発 生 工 学 研 究 室) Chimerism is a condition in which an individual has two or more genetically distinct populations of cells originating from different zygotes. The development of interspecies chimeras, which consist of two distinct species of cells in one body, will certainly benefit regenerative medicine as well as disease modeling. For example, it could enable animals to generate human-compatible organs, thereby reducing the lack of organs available for transplantation. However, chimerism, which refers to the proportion of several types of cells in each chimeric organ or body, also presents several hurdles, including issues with immunological responses, developmental compatibility, and ethical issues. Research in this area is necessary to further our understanding of the variables that affect chimerism, such as immune system interactions, developmental timing, and genetic compatibility. Therefore, our goal is to comprehend mouse and rat cells' distribution, integration, and functionality throughout various organ systems. This work focuses on the chimerism disparities between organs in mouse-rat interspecies chimeras. To investigate the chimerism difference between selected organs: lung, kidney, and tail in mouse-rat interspecies chimera, administration of Luteinizing Hormone-Releasing Hormone agonist (LHRHa) to ICR strain wild-type (WT) female mice was initiated and mated with a vasectomized (VAS) WT male mouse to produce pseudopregnant mice. This was followed by superovulation via Pregnant Mare Serum Gonadotropin (PMSG)/human Chorionic Gonadotropin (hCG) administration to either the ICR or BDF strain WT female mice and mated with ICR WT male mice to obtain fertilized eggs (blastocyst embryos). Rat embryonic stem (rES) cell lines were injected into blastocyst stage embryos using a pulled microglass needle, and the injected blastocysts were surgically transferred into the uteri of pseudopregnant surrogate mothers. Interspecies chimeric fetuses that expressed green fluorescent protein (GFP) in the rES cell-derived cell were obtained, and the distribution of cells from rats and mice in organs, including the lung, kidney, and tail, was analyzed using flow cytometry. Our findings reveal significant differences in chimerism levels between organs. For instance, in intraspecies chimera, the lung, kidney, and tail exhibit about equal distributions of chimerism; nevertheless, in interspecies chimera, the lung exhibited a larger proportion of rat cells while the kidney and tail exhibited a larger proportion of mouse cells. Numerous factors, including developmental time and compatibility, the immune system, cell proliferation and survival, genetic and epigenetic factors, organ-specific factors, and experimental methodologies, are responsible for these discrepancies. In conclusion, research on the variations in chimerism among the organs in interspecies chimeras between mice and rats offers an important understanding of the processes underlying organogenesis and cellular integration. These results open new avenues for regenerative medicine research and the creation of creative treatment approaches. Figure 1. Methods for the generation of mouse and rat interspecies chimeras. Adapted from Isotani, A. et al., (2011). Figure 2. The difference in chimerism between intraspecies and interspecies chimeras.