The role of smooth muscle in regulating prostatic induction (original) (raw)
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The Anatomical record, 1973
Standard tissue culture and epithelio-mesenchymd separation and recombination techniques were applied to the question of sex determination of the male urogenital sinus of embryonic mice. Explants of urogenital sinuses from 12-to 17day old embryos were cultured in an androgen-free environment to a gestational age equivalency of 18 to 20 days. The developmental response of these explants led to the following conclusions: (1) Androgens are necessary for initiation of prostatic bud outgrowth; (2) The effect of androgens can be demonstrated at the stage when the fetal testis begins to secrete androgens; and (3) Prior to the appearance of prostatic buds, the urogenital sinus has the capacity to pursue that developmental end-point independently of further androgen stimulation. In addition, the developmental response of recombinants composed of androgen-treated and untreated epithelium and mesenchyme from the urogenital sinus has shown that it is the epithelium which is primarily determined by androgens during prostatic morphogenesis.
The Journal of cell biology, 1983
Adult bladder epithelium (BLE) is induced to differentiate into glandular epithelium after association with urogenital sinus mesenchyme (UGM) and subsequent in vivo growth in syngeneic male hosts. Alteration of epithelial cytodifferentiation is associated with the expression of prostate-specific antigens, histochemical and steroid metabolic activities. These observations suggest that the inductive influence of the UGM has reprogrammed both the morphological and functional characteristics of the urothelium. In this report, differences regarding the mechanisms and effects of androgenic stimulation of prostate and bladder are exploited to determine the extent to which UGM plus BLE recombinants express a prostatelike, androgen-dependent phenotype. Results from cytosolic and autoradiographic binding studies suggest that androgen binding is induced in UGM plus BLE recombinants and that this activity is accounted for by the induced urothelial cells. In UGM plus BLE recombinants, androgen-i...
Journal of Cell Biology, 1983
Tissue recombinants of embryonic urogenital sinus mesenchyme (UGM) and epithelium of the urinary bladder (urothelium, BLE) of adult rats and mice were grown for 3-30 d in male syngeneic hosts. Short-term in vivo growth indicated that prostatic morphogenesis is initiated as focal outgrowths from the basal aspect of the adult urothelium. The solid epithelial buds elongate, branch, and subsequently canalize, forming prostatic acini. After 30 d of growth in the male hosts, prostatic acini exhibit secretory activity. The marked changes in urothelial morphology induced by the UGM are accompanied by the expression of fine-structural features indicative of secretory function (rough endoplasmic reticulum, Golgi apparatus,.and secretory granules). During this process, urothelial cells express prostatic histochemical markers (alkaline phosphatase, nonspecific esterase, glycosaminoglycans) and prostate-specific antigens. The expression within BLE of prostatic characteristics is associated with the loss of urothelial characteristics. These data indicate that adult urothelial cells retain a responsiveness to embryonic mesenchymal inductors. Furthermore, mesenchyme-induced changes in urothelial cytodifferentiation appear to be coupled to changes in functional activity. MATERIALS AND METHODS Tissues were obtained from inbred BALB/c mice and Fisher 344 rats (Charles River Breeding Laboratories, Inc., Wilmington, MA). Urogenital sinuses were
Cell Biology International, 2005
In this study, we evaluated the involvement of rat ventral prostate smooth muscle cells (SMC) in secretory activity and whether this function is modulated after castration. Cell morphology was examined at both light and electron microscopy levels and the organelles involved in secretory function were labeled by the zinc-iodide-osmium (ZIO) method at the ultrastructural level and their volume density was determined by stereology. Castration resulted in marked changes of the SMC, which adopted a spinous aspect and abandoned the layered arrangement observed in the prostates of non-castrated rats. The volume density of ZIO reactive organelles increased progressively after castration, reaching significantly higher levels 21 days after castration. Since previous studies have demonstrated that SMC express SMC markers (even 21 days after castration) and are able to respond to adrenergic stimulation, we concluded that differentiated SMC are able to shift from a predominantly contractile to a more synthetic phenotype without changing their differentiation status. Ó
Ontogeny of the male urethra: Theory of endodermal differentiation
Differentiation, 1999
The most widely accepted mechanism of male urethral development proposes that the urethral plate is elevated by urethral folds which fuse ventrally in a proximal-to-distal sequence. Unlike its proximal counterpart, the urethra which forms within the glans is lined by a stratified squamous epithelium and has a more controversial development. One theory supports the idea that fusion of the urethral folds extends all the way to the tip of the glans. Another theory suggests that a solid ectodermal ingrowth of epidermis canalizes the glandar urethra. We hypothesized that the use of immunohistochemical staining and tissue recombinant grafting would delineate the epithelia involved and lend clues to their origin. Thirty-six human fetal phallic specimens of gestational ages 5-22 weeks were sectioned and stained immunohistochemically with antibodies raised against different cytokeratins. Evaluation of the sections showed that the urethral plate, an extension of the urogenital sinus, extended to the tip of the phallus and maintained patency and continuity throughout the process of urethral development. The entire urethra, including the glans portion, was formed by dorsal extension and disintegration of the urethal plate combined with ventral growth and fusion of the urethral folds. Sections of the distal glandar urethra showed no evidence of a solid ectodermal ingrowth. Rather, immunostaining results at different ages suggested differentiation of the endodermal urethral plate into a stratified squamous epithelium. To determine whether urothelium could be induced to express a stratified squamous phenotype, mouse fetal bladder epithelium was combined with rat fetal genital tubercle mes-enchyme and grown under the renal capsule of athymic mice. The bladder epithelium differentiated into a stratified squamous epithelium. Thus, proper mesenchymal signaling may induce differentiation of urothelium into a stratified squamous phenotype, such as during development of the urethra of the glans penis.
Tissue interactions between epithelium and mesenchyme of urogenital and integumental origin
The Anatomical record, 1972
Trypsin-separated epithelia and mesenchyme were prepared from the following urogenital and integumental tissues of embryonic mice : seminal vesicle, urogenital sinus, preputial gland, and back, snout, and plantar surface foot plate skin. These components were rejoined in control (homotypic) and experimental (heterotypic) recombinants and were subsequently grown for one to three weeks as intraocular grafts to adult male hosts. Grafts of intact rudiments provided additional control data. In heterotypic recombinants composed of urogenital epithelia (urogenital sinus or seminal vesicle) and integumental mesenchyme (back, snout, or plantar), the epithelium responded as if androgens were absent, i.e., urogenital sinus epithelium formed a keratinized structure, while seminal vesicle epithelium developed into a small tubule of columnar epithelium. On the other hand, plastic integumental epithelia (snout or plantar) was transformed by urogenital mesenchyme of the urogenital sinus or seminal vesicle into a glandular epithelium characteristic of the mesenchymal source. Similarly, the normally glandular preputial gland epithelium could be induced to form keratinized, hair-bearing skin by back and snout skin dermis, and although preputial gland mesenchyme did not manifest inductive properties when associated with integumental mesenchyme, it was able to participate in typical skin differentiation. These data demonstrate (1) the importance of the mesenchyme in mediating epithelial response to androgens, (2) the stability of urogenital epithelia, (3) the plasticity of integumental epithelia, and ital and integumental mesenchyme.
Induction of prostatic morphology and secretion in urothelium by seminal vesicle mesenchyme
Development (Cambridge, England), 1995
Mesenchymal-epithelial interactions are essential for the development of the male reproductive tract. Tissue recombination experiments have been used to define the characteristics of these interactions. When mesenchyme, embryonic connective tissue, is recombined with epithelium from another organ an instructive induction may occur in which the developmental fate of the epithelium is altered. Instructive inductions are most common when the epithelium that is removed from the mesenchyme and the epithelium that is recombined with the mesenchyme are from the same germ layer. All of the mesenchyme of the male reproductive tract is of mesodermal origin. The epithelia of these organs are derived from either the mesodermal Wolffian duct epithelium or the endodermal urogenital sinus epithelium. Urogenital sinus mesenchyme can instructively induce bladder and urethral epithelium to form prostate (Donjacour, A. A. and Cunha, G. R. (1993) Endocrinol. 132, 2342-2350) and seminal vesicle mesenchy...
MESENCHYMAL-EPITHELIAL INTERACTIONS IN BLADDER SMOOTH MUSCLE DEVELOPMENT
The Journal of Urology, 1998
Purpose: We have previously shown that mesenchymal-epithelial interactions are necessary for the development of bladder smooth muscle. Specifically without fetal or adult urothelium embryonic rat bladder mesenchyma does not differentiate into smooth muscle. The mechanism responsible for this interaction is not known, although it is postulated that diffusable growth factors have a role. Our hypothesis is that diffusable factors within adult rat bladders influence smooth muscle differentiation.