Differential manifestation of ocular phenotypes in TALEN-mediated p19arf knockout FVB/N and C57BL/6J mouse lines.

BACKGROUND: p19arf, primarily known as a tumor suppressor, has also been reported to play an essential role in normal development of mouse eyes. Consistently, lack of p19arf has been associated with ocular defects, but the mixed background of the knockout (KO) mouse strain used raised a concern on the accuracy of the phenotypes observed in association with the targeted gene due to genetic heterogeneity. OBJECT: We carried out a study to investigate into the effect of genetic background on the manifestation of p19arf KO associated phenotypes. METHODS: We characterized the phenotypes of novel p19arf KO mouse lines generated in FVB/N and C57BL/6J using a transcription activator-like effector nuclease (TALEN) system in comparison to the reported phenotypes of three other p19arf-deficient mouse lines generated using homologous recombination. RESULTS: Ninety-five percent of FVB/N-p19arf KO mice showed ocular opacity from week 4 after birth which worsened rapidly until week 6, while such abnormality was absent in C57BL/6J-p19arf KO mice up to the age of 26 weeks. Histopathological analysis revealed retrolental masses and dysplasia in the retinal layer in FVB/N-p19arf KO mice from week 4. Besides these, both strains developed normally from birth to week 26 without increased tumorigenesis except for a subcutaneous tumor found in a C57BL/6J-p19arf KO mouse. CONCLUSION: Our findings demonstrated surprisingly variable manifestation of p19arf-linked phenotypes between FVB/N and C57BL/6J mice, and furthermore between our mouse lines and the established lines, indicating a critical impact of genetic background on functional study of genes using gene targeting strategies in mice.

Dual chemotactic factors-secreting human amniotic mesenchymal stem cells via TALEN-mediated gene editing enhanced angiogenesis.

BACKGROUND: Even though mesenchymal stem cells (MSCs) have angiogenic property, their cytokine secretory capacity is limited to treat ischemic vascular disorders. In present study, we produced genome-edited MSCs that secreted dual chemokine granulocyte chemotactic protein-2 (GCP-2) and stromal-derived factor-1α (SDF-1α) and determined their therapeutic potential in the context of experimental ischemia. METHODS: GCP-2 and SDF-1α genes were integrated into safe harbor site at the safe harbor genomic locus of amniotic mesenchymal stem cells (AMM) via transcription activator-like effector nucleases (TALEN). GCP-2 and SDF-1α gene-edited AMM (AMM/GS) were used for quantitative (q)-PCR, Matrigel tube formation, cell migration, Matrigel plug assays and in vivo therapeutic assays using hindlimb ischemia mouse model. RESULTS: AMM/GS-derived culture media (CM) induced significantly higher tube lengths and branching points as compared to AMM/S CM and AMM CM. Interestingly, Matrigel plug assays revealed that significantly higher levels of red blood cells were found in AMM/GS than AMM/S and AMM Matigel plugs and exhibited micro-vascular like formation. Cells was transplanted into ischemic mouse hindlimbs and compared with control groups. AMM/GS injection prevented limb loss and augmented blood perfusion, suggesting that enhances neovascularization in hindlimb ischemia. In addition, transplanted AMM/GS revealed high vasculogenic potential in vivo compared with transplanted AMM/S. CONCLUSION: Taken together, genome-edited MSCs that express dual chemokine GCP-2 and SDF-1α might be alternative therapeutic options for the treatment of ischemic vascular disease.