Directed differentiation of bone marrow derived mesenchymal stem cells into bladder urothelium.
OBJECTIVE
We have previously reported that embryonic rat bladder mesenchyma has the appropriate inductive signals to direct pluripotent mouse embryonic stem cells toward endodermal derived urothelium and develop mature bladder tissue. We determined whether nonembryonic stem cells, specifically bone marrow derived mesenchymal stem cells, could serve as a source of pluripotent or multipotent progenitor cells.


METHODS
Epithelium was separated from the mesenchymal shells of embryonic day 14 rat bladders. Mesenchymal stem cells were isolated from mouse femoral and tibial bone marrow. Heterospecific recombinant xenografts were created by combining the embryonic rat bladder mesenchyma shells with mesenchymal stem cells and grafting them into the renal subcapsular space of athymic nude mice. Grafts were harvested at time points of up to 42 days and stained for urothelial and stromal differentiation.


RESULTS
Histological examination of xenografts comprising mouse mesenchymal stem cells and rat embryonic rat bladder mesenchyma yielded mature bladder structures showing normal microscopic architecture as well as proteins confirming functional characteristics. Specifically the induced urothelium expressed uroplakin, a highly selective marker of urothelial differentiation. These differentiated bladder structures demonstrated appropriate alpha-smooth muscle actin staining. Finally, Hoechst staining of the xenografts revealed nuclear architecture consistent with a mouse mesenchymal stem cell origin of the urothelium, supporting differentiated development of these cells.


CONCLUSIONS
In the appropriate signaling environment bone marrow derived mesenchymal stem cells can undergo directed differentiation toward endodermal derived urothelium and develop into mature bladder tissue in a tissue recombination model. This model serves as an important tool for the study of bladder development with long-term application toward cell replacement therapies in the future.
Anumanthan
Govindaraj
G
Department of Urologic Surgery, Vanderbilt University Medical Center and Division of Pediatric Urology, Vanderbilt Children's Hospital, Nashville, Tennessee, USA.
Makari
John H
JH
Honea
Lindsey
L
Thomas
John C
JC
Wills
Marcia L
ML
Bhowmick
Neil A
NA
Adams
Mark C
MC
Hayward
Simon W
SW
Matusik
Robert J
RJ
Brock
John W
JW
Pope
John C
JC
D000818:Animals; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008819:Mice, Nude; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014183:Transplantation, Heterologous; D001743:Urinary Bladder / Q000166:cytology* / Q000378:metabolism; D019459:Urothelium / Q000166:cytology / Q000378:metabolism