Abstract

Simple Summary Prostaglandin E2 plays a regulatory role in MSC self-renewal, and PGE2 receptor-mediated signalling is involved in cell proliferation and migration. The aim of this work was to establish a genetically modified equine cellular model in which receptor genes EP2 and EP4 were edited by the CRISPR/Cas9 system. We successfully targeted EP2 and EP4 receptors in horse adipose MSCs using the CRISPR/Cas9 system. This targeting did not affect the surface marker phenotype of the adipose MSCs generated. Gene edition significantly lowered the expression of each of the targeted receptors and affected the early migration ability of the edited MSCs. This opens the possibility of using these mutant cell lines as a model system to elucidate the role of EP2 and EP4 in MSCs and, particularly, as therapeutic tools in equine regenerative medicine. In mesenchymal stem cells (MSCs), it has been reported that prostaglandin E2 (PGE2) stimulation of EP2 and EP4 receptors triggers processes such as migration, self-renewal, survival, and proliferation, and their activation is involved in homing. The aim of this work was to establish a genetically modified adipose (aMSC) model in which receptor genes EP2 and EP4 were edited separately using the CRISPR/Cas9 system. After edition, the genes were evaluated as to if the expression of MSC surface markers was affected, as well as the migration capacity in vitro of the generated cells. Adipose MSCs were obtained from Chilean breed horses and cultured in DMEM High Glucose with 10% fetal bovine serum (FBS). sgRNA were cloned into a linearized LentiCRISPRv2GFP vector and transfected into HEK293FT cells for producing viral particles that were used to transduce aMSCs. GFP-expressing cells were separated by sorting to obtain individual clones. Genomic DNA was amplified, and the site-directed mutation frequency was assessed by T7E1, followed by Sanger sequencing. We selected 11 clones of EP2 and 10 clones of EP4, and by Sanger sequencing we confirmed 1 clone knock-out to aMSC/EP2 and one heterozygous mutant clone of aMSC/EP4. Both edited cells had decreased expression of EP2 and EP4 receptors when compared to the wild type, and the edition of EP2 and EP4 did not affect the expression of MSC surface markers, showing the same pattern in filling the scratch. We can conclude that the edition of these receptors in aMSCs does not affect their surface marker phenotype and migration ability when compared to wild-type cells.