Temporal-spatial protein expression in bladder tissue derived from embryonic stem cells.
OBJECTIVE
Identifying developmental proteins could lead to markers of bladder progenitor cells, which could be used to investigate bladder diseases. We recently reported a novel embryonic stem cell model in which to study differential protein expression patterns during bladder development. Differential and temporal expressions of the endodermal proteins known as forkhead box (Foxa1 and Foxa2) were observed. In the current study we further delineated these protein expression patterns.


METHODS
Epithelium was removed from the underlying mesenchyma from embryonic day 18 rat bladders. Heterospecific recombinant xenografts were created by combining embryonic stem cells plus embryonic bladder mesenchyma and placed beneath the renal capsule of mouse hosts. Grafts were harvested at 16, 18, 21, 28, 35 and 42 days, and evaluated with hematoxylin and eosin, trichrome staining, and immunohistochemistry for uroplakin, smooth muscle alpha-actin, p63, Foxa1, Foxa2 and androgen receptor.


RESULTS
At 16 days uroplakin was detectable and it seemed to correlate with the loss of Foxa2, while Foxa1 remained at all time points. Androgen receptor was first noted in stroma at day 16. It localized to urothelial nuclei at day 21 and was undetectable at 42 days. Adjacent to the urothelium alpha-smooth muscle actin was seen on day 16 and it was localized in bundles to the periphery of the graft at later time points. Staining for basilar urothelium with p63 confirmed basilar orientation at all time points.


CONCLUSIONS
We report the temporal spatial expression of various genes in early bladder development. This suggests that some proteins may be potential markers of bladder progenitor cells. Characterizing these markers may potentially identify bladder progenitor cells that have been directed toward a lineage path destined to become urothelial cells. Ultimately these multipotential progenitor cells could be isolated and used to study and treat diseases that affect the bladder.
Thomas
John C
JC
Department of Urologic Surgery, Vanderbilt University Medical Center, Division of Pediatric Urology, Monroe Carell Jr. Vanderbilt Children's Hospital, Nashville, Tennessee 37232, USA. john.thomas@vanderbilt.edu
Oottamasathien
Siam
S
Makari
John H
JH
Honea
Lindsay
L
Sharif-Afshar
Ali-Reza
AR
Wang
Yongqing
Y
Adams
Cyrus
C
Wills
Marcia L
ML
Bhowmick
Neil A
NA
Adams
Mark C
MC
Brock
John W
JW
Hayward
Simon W
SW
Matusik
Robert J
RJ
Pope
John C
JC
D000818:Animals; D053595:Embryonic Stem Cells / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051541:Hepatocyte Nuclear Factor 3-alpha; D051542:Hepatocyte Nuclear Factor 3-beta; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008819:Mice, Nude; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells; D023822:Tissue Engineering; D014183:Transplantation, Heterologous; D001743:Urinary Bladder / Q000166:cytology / Q000196:embryology*; D060171:Uroplakin III
C496500:Foxa1 protein, mouse; C496503:Foxa2 protein, mouse; D051541:Hepatocyte Nuclear Factor 3-alpha; D008562:Membrane Glycoproteins; D060171:Uroplakin III; D051542:Hepatocyte Nuclear Factor 3-beta