In order to stimulate the differentiation of one induced collecting duct into a ureter-like structure using Mills technique, organoids had to be cultured in absence of Matrigel as the gel impedes the positioning of the beads. However, we observed that the MM surrounding the iUB started dying 24hs after the reconstruction, which subsequently led to failure of the tissue. Which raises a question about the role of Matrigel in the success of the reconstruction process.
Conclusion and future work:
We efficiently reproduced mESC derived iUBs and iNPs using the Taguchi induction protocol. In the PWM of a host kidney the induced UB behaved like the ureteric stalk, it expressed uroplakin and did not show branching. However, there is a variability in their behaviour in the MM, where some samples showed uroplakin expression in their trunks. To clarify, whether the expression of the uroplakin in MM transplanted iUBs, was caused by the differentiation media or the Matrigel, this experiment will be repeated using a naturally derived UB as a control. Moreover, the future work will focus on improving the survival of the MM in culture and develop a practical method to apply the BMP4 bead treatment, or find alternative way to create the Taguchi style organoid with a single exit.