Biomedical subjects

Wade Bushman

Publications and source records attributed to Wade Bushman.

12 recordsLinked to original sources

PubMed2007

Chronic bacterial infection and inflammation incite reactive hyperplasia in a mouse model of chronic prostatitis.

BACKGROUND: Chronic inflammation is postulated to contribute to prostate carcinogenesis. We developed a mouse model of chronic prostatitis to test whether infection-induced chronic inflammation would incite reactive changes in prostatic epithelium. METHODS: Prostate tissues harvested from either phosphate-buffered saline (PBS) or E. coli-infected mice were evaluated for histological changes and immunostained for markers of oxidative stress and epithelial cell proliferation. RESULTS: As compared to PBS-treated controls, mice infected with E. coli bacteria for 5 days showed foci of uniformly acute inflammation in the glandular lumen and a persistent inflammation at 12 weeks post-inoculation in the stroma. Prostatic glands showing varying degrees of atypical hyperplasia and dysplasia had stronger staining for oxidative DNA damage and increased epithelial cell proliferation than normal prostatic glands. CONCLUSIONS: These data demonstrate that chronic inflammation induces reactive hyperplasia associated with oxidative stress injury and support the proposed linkage among inflammation, oxidative DNA damage, and prostate carcinogenesis.

Animals↗

PubMed2006

Isolation and characterization of an immortalized mouse urogenital sinus mesenchyme cell line.

BACKGROUND: Stromal-epithelial signaling plays an important role in prostate development and cancer progression. Study of these interactions will be facilitated by the use of suitable prostate cell lines in appropriate model systems. METHODS: We have isolated an immortalized prostate mesenchymal cell line from the mouse E16 urogenital sinus (UGS). We characterized its expression of stromal differentiation markers, response to androgen stimulation, ability to induce and participate in prostate morphogenesis, response to Shh stimulation, and interaction with prostate epithelial cells. RESULTS: UGSM-2 cells express vimentin and smooth muscle actin, but not the mature smooth muscle markers myosin and desmin. This expression profile is consistent with a myofibroblast phenotype. Unlike other fibroblasts such as 3T3, UGSM-2 cells express androgen receptor mRNA and androgen stimulation increases proliferation. UGSM-2 cells are viable when grafted with embryonic UGS under the renal capsule and participate in glandular morphogenesis, but are not capable of inducing prostate morphogenesis of isolated UGS epithelium. Co-culture of UGSM-2 cells with human BPH-1 cells or co-grafting in vivo results in organized clusters of BPH-1 cells surrounded by a mantle of UGSM-2 cells. UGSM-2 cells are responsive to Sonic hedgehog (Shh), an important signaling factor in prostate development, and mimic the transcriptional response of the intact UGS mesenchyme. In co-cultures with BPH-1, UGSM-2 cells exhibit a robust transcriptional response to Shh secreted by BPH-1. CONCLUSIONS: UGSM-2 is a urogenital sinus mesenchyme cell line that can be used to study stromal-epithelial interactions that are important in prostate biology.

Actins↗

PubMed2006

Functional compensation in Hedgehog signaling during mouse prostate development.

Studies of hedgehog signaling in prostate development using anti-Shh antibodies, chemical inhibitors of hedgehog signaling and Shh(-/-) mutant mice have yielded conflicting data regarding the requirements of hedgehog signaling for normal ductal budding and glandular morphogenesis. We used transgenic mouse models in combination with chemical inhibitors and renal grafting to clarify the role of Hh signaling in prostate development. These studies showed that genetic loss of Shh is accompanied by an up-regulation of Indian Hedgehog (Ihh) and maintenance of Hh pathway activity. We found that while neither Gli1 nor Gli3 are required for normal prostate ductal budding, the urogenital sinus (UGS) of the Gli2(-/-) mutant mouse displays aberrant ductal budding in utero. When grown as a subcapsular graft, the Gli2(-/-) UGS exhibited prostatic differentiation but also displayed areas of focal epithelial hyperplasia. Functional redundancy between the three Gli transcription factors appears to mitigate the effect of Gli2 LOF as evidenced by residual Hh pathway activity in the E14 Gli2(-/-) UGS that could be inhibited by cyclopamine treatment. Together, these studies reveal a surprising degree of functional redundancy operating both at the level of the ligand and at the level of transcriptional regulation that effectively mitigates phenotypes associated with Hh-signaling perturbations.

Animals↗

PubMed2006

Unique and complimentary activities of the Gli transcription factors in Hedgehog signaling.

The Gli family of transcription factors (Gli1, 2 and 3) mediate the Hedgehog morphogenetic signal by regulating the expression of downstream target genes. Aberrations in Hedgehog signaling seriously affect vertebrate development. Postnatally, Hedgehog signaling has been postulated to play a pivotal role in healing and repair processes and inappropriate pathway activation has been implicated in several types of cancers. To better understand both the upstream regulation of the Gli transcription factors, as well as their unique and combinatorial roles in regulating the expression of Hedgehog target genes, we have characterized embryonic fibroblasts (MEFs) from Gli mutant mice. Stimulation of wild-type MEFs by Sonic Hedgehog (Shh) peptide elicited unique profiles of induction of Hedgehog target genes Gli1, Ptc1, and Hip1. Gli2 loss-of-function was associated with diminished Shh-induced target gene expression, while Gli3 loss-of-function was associated with increased basal and Shh-induced target gene expression. The loss of Gli1 alone had no effect on target gene induction but did diminish Shh-induced target gene expression when combined with the loss of Gli2 or Gli3. Additionally, overexpression of Gli1 induced target gene expression in Gli2(-/-)3(-/-) MEFs, while Shh stimulation did not. Using MEFs expressing only Gli2 or Gli3, we found that both cyclopamine and the PKA activator forskolin inhibited target gene induction mediated by Gli2 and Gli3. These results demonstrate that Gli2 and Gli3 share common regulatory mechanisms and modulate Hedgehog target gene expression directly and independently while also regulating Gli1 expression, which in specific contexts, coordinately contributes to target gene activation.

Animals↗

PubMed2005

Sonic hedgehog signaling regulates the expression of insulin-like growth factor binding protein-6 during fetal prostate development.

At the onset of ductal morphogenesis in the developing prostate, Shh expression condenses at evaginations of urogenital sinus epithelium and activates Gli transcription factors in the adjacent mesenchyme. Abrogation of Hedgehog signaling disrupts proper prostatic budding, ductal growth, and branching. We now show that Hedgehog signaling regulates the expression of insulin-like growth factor binding protein-6 (Igfbp-6) in the developing mouse prostate. Igfbp-6 is a secreted factor that specifically binds insulin-like growth factor-II (IGF-II), prevents its binding to the IGF-I receptor, and is thought to regulate the activity of IGF-II in growth and differentiation. Igfbp-6 is expressed in both the developing and adult prostate. In the urogenital sinus, Igfbp-6 mRNA colocalized with Ptc1 and Gli1 mRNA in the mesenchyme, while Igfbp-6 protein was found in both the mesenchymal and epithelial layers. Exogenous Shh peptide induced expression of Igfbp-6 in the developing prostate while the chemical inhibitor of Hedgehog signaling, cyclopamine, reduced its expression. These studies show that Igfbp-6 is an actual target of Shh signaling in the urogenital sinus and provide the first evidence for a linkage between the Hedgehog and IGF signaling pathways in prostate development.

Animals↗

PubMed2004

Hedgehog signaling promotes prostate xenograft tumor growth.

During fetal prostate development, Sonic hedgehog (Shh) expression by the urogenital sinus epithelium activates Gli-1 expression in the adjacent mesenchyme and promotes outgrowth of the nascent ducts. Shh signaling is down-regulated at the conclusion of prostate ductal development. However, a survey of adult human prostate tissues reveals substantial levels of Shh signaling in normal, hyperplasic, and malignant prostate tissue. In cancer specimens, the Shh expression is localized to the tumor epithelium, whereas Gli-1 expression is localized to the tumor stroma. Tight correlation between the levels of Shh and Gli-1 expression suggests active signaling between the tissue layers. To determine whether Shh-Gli-1 signaling could be functionally important for tumor growth and progression, we performed experiments with the LNCaP xenograft tumor model and demonstrated that: 1). Shh expressed by LNCaP tumor cells activates Gli-1 expression in the tumor stroma, 2). genetically engineered Shh overexpression in LNCaP cells leads to increased tumor stromal Gli-1 expression, and 3). Shh overexpression dramatically accelerates tumor growth. These data suggest that hedgehog signaling from prostate cancer cells to the stroma can elicit the expression of paracrine signals, which promote tumor growth.

Adult↗

PubMed2004

Do pad tests and voiding diaries affect patient willingness to participate in studies of incontinence treatment outcomes?

PURPOSE: We used the Simplified Urinary Incontinence Outcome Score (SUIOS) to retrospectively assess the continence outcomes following 107 consecutive autologous rectus fascia pubovaginal sling procedures. This outcome score requires completion of a questionnaire, voiding diary and pad test. The voiding diary and pad test provide objective data but require a degree of patient effort and motivation. We determine if the voiding diary and pad test requirements would significantly reduce the rate of followup. MATERIALS AND METHODS: After recruitment letters were mailed to all eligible patients, followup telephone calls were made to ask them to complete the SUIOS protocol. Those who agreed were mailed a packet containing the pre-weighed pads, voiding diary and questionnaire. Patients who refused were asked to complete a telephone questionnaire instead. Patients were given 1 month to complete and return the study materials. If the materials were not returned, repeat telephone reminders were made. If patients were unwilling to complete the protocol at this point, they were offered the option of completing only the questionnaire by telephone. Treatment outcomes were classified according to the SUIOS protocol, and the followup rate for the full protocol was compared with that for the questionnaire only responses. RESULTS: Of the 107 patients 18 were lost to followup and 10 refused to participate, leaving 79 (74%) evaluable patients. Mean followup interval was 31 months (range 9 to 66). Of the 79 women 38 (48%) completed the questionnaire portion but were unwilling to complete the voiding diary and pad test. The remaining 41 patients (52%) completed the entire protocol. Complete SUIOS scores were 59% cured, 24% good response, 10% fair response, 2% poor response and 5% failure. Questionnaire response results were similar, with 61% cured, 32% improved and 8% failed. CONCLUSIONS: The majority of our patients were unwilling to complete a pad test and voiding diary for the purpose of assessing outcomes after anti-incontinence surgery. The possible increased accuracy of these outcome measures needs to be weighed against the lower followup rate associated with their use.

Adult↗

PubMed2003

Urologic and plastic surgical collaboration for continent diversion when urine leakage is complicated by pressure ulcers or obesity.

BACKGROUND: Patients with neurogenic bladder dysfunction and urine leakage combined with pressure ulceration, fistulae, and/or obesity present a major surgical challenge. Given the urgent need to control urine leakage, suprapubic cystostomy or incontinent urinary diversion such as ileal conduit often are chosen for definitive intervention, despite the fact that continent urinary diversion generally is the preferred method of management for the motivated patient. DESIGN: Case series. METHOD: This article presents 4 patients in whom urine leakage was complicated by pressure ulcers, urethral erosion, and/or morbid obesity. Due to the complicated nature of their problems, these patients were managed in a collaborative fashion by the departments of urology, plastic surgery, and physiatry. Each of these patients underwent a combined surgical intervention that addressed issues of skin ulceration or morbid obesity and allowed for continent urinary diversion. RESULTS: After intervention, all 4 patients were independent in bladder management and were completely continent. CONCLUSION: This series demonstrates how collaboration between the urologist and plastic surgeon in evaluation and treatment planning allows for the formulation of surgical options that include continent urinary diversion.

Adolescent↗

PubMed2002

Sonic hedgehog activates mesenchymal Gli1 expression during prostate ductal bud formation.

Ductal budding in the developing prostate is a testosterone-dependent event that involves signaling between the urogenital sinus epithelium (UGE) and urogenital sinus mesenchyme (UGM). We show here that ductal bud formation is associated with focused expression of Sonic hedgehog (Shh) in the epithelium of nascent prostate buds and in the growing tips of elongating prostate ducts. This pattern of localized Shh expression occurs in response to testosterone stimulation. The gene for the Shh receptor, Ptc1, is expressed in the UGM, as are the members of the Gli gene family of transcriptional regulators (Gli1, Gli2, and Gli3). Expression of Ptc1, Gli1, and Gli2 is localized primarily to mesenchyme surrounding prostate buds, whereas Gli3 is expressed diffusely throughout the UGM. A strong dependence of Gli1 (and Ptc1) expression on Shh signaling is demonstrated by induction of expression in both the intact urogenital sinus and the isolated UGM by exogenous SHH peptide. A similar dependence of Gli2 and Gli3 expression on Shh is not observed. Nonetheless, the chemical inhibitor of Shh signaling, cyclopamine, produced a graded inhibition of Gli gene expression (Gli1>Gli2>Gli3) in urogenital sinus explants that was paralleled by a severe inhibition of ductal budding.

Animals↗

PubMed2002

Urodynamic evaluation of the human bladder response to an increase in outlet resistance.

AIM: We prospectively evaluated the response of the human bladder to a chronic increase in urethral resistance according to the indices of pressure, volume flow rate, total (external) bladder work, and maximum and average detrusor power. METHODS: Six men with incontinence after radical prostatectomy were evaluated urodynamically before and 3-6 months after undergoing a bulbourethral sling procedure. RESULTS: None of the men suffered from significant obstructive or irritative voiding symptoms preoperatively. Urodynamic evaluation showed postoperative increases in both average detrusor pressure and pressure at maximum flow, but there were no significant changes in voided volume, void time, or postvoid residual urine volume. Maximum detrusor power, average detrusor power, and total (external) bladder work were all significantly increased. CONCLUSION: These data confirm that the human bladder possesses a functional reserve, which is elicited by an increase in urethral resistance.

Aged↗

PubMed2002

The human prostate expresses sonic hedgehog during fetal development.

PURPOSE: The keynote event of prostate ductal development is the formation of epithelial buds that invade the urogenital sinus mesenchyma. Studies in mice have shown that budding requires the signaling peptide, which is expressed in the epithelium of the prostatic anlagen. We report our characterization of (SHH) expression in the human fetal prostate. MATERIALS AND METHODS: Reverse transcriptase-polymerase chain reaction was performed in fetal prostate RNA isolated at 15.5 and 18 weeks of gestation, respectively. Immunostaining was performed on sections from 7 male fetuses at 9.5 to 34 and in 4 female fetuses at 9 to 18 weeks of gestation. RESULTS: Weak staining for was seen in the prostatic urethra at 9.5 weeks. Intense staining was seen at 11.5 and 13 weeks in the prostatic urothelium and nascent prostatic buds. Staining was slightly diminished at 16.5, further diminished at 18 to 20 and absent at 34 weeks. expression at 15.5 and 18 weeks was confirmed by reverse transcriptase-polymerase chain reaction assay of freshly isolated prostate tissue. Comparative immunostaining in the female showed urothelial staining at 9 and 12 weeks with staining greatest above the entrance of the müllerian ducts. Staining diminished earlier in the female (14 weeks) than in the male and was almost absent at 18 weeks. CONCLUSIONS: expression in the human fetal prostate is contemporaneous with the fetal testosterone surge and with ductal budding of the prostatic urothelium. expression is also present in the female urogenital sinus but in the absence of testosterone it is not associated with ductal budding.

Female↗

PubMed2002

Polypropylene mesh tape for stress urinary incontinence: complications of urethral erosion and outlet obstruction.

PURPOSE: Gynecare tension-free vaginal tape (Ethicon, Inc., New Brunswick, New Jersey) is a propylene mesh tape recently introduced in the United States as minimally invasive treatment for stress urinary incontinence. We report the combined experience at 3 tertiary care institutions with graft erosion and bladder outlet obstruction after procedures performed elsewhere. MATERIALS AND METHODS: We reviewed the records of 5 patients with complications who presented to 1 of 3 institutions after polypropylene mesh tape placement. All pertinent information was obtained from the medical records and the operating surgeon at the referring institution. RESULTS: Treatment was required in 2 patients with urethral erosion, 1 with vaginal and bladder erosion, and 2 with bladder outlet obstruction. Common presenting symptoms included urge, urge incontinence and gross hematuria. Cystoscopy showed polypropylene graft erosion at the urethra or through the bladder wall. Each patient required explantation of the polypropylene mesh tape and further surgery to restore continence. The graft was divided transvaginally in the 2 patients presenting with outlet obstruction. Urge incontinence resolved and they returned to complete spontaneous voiding. CONCLUSIONS: High clinical suspicion is necessary when evaluating patients presenting with urinary symptoms after polypropylene mesh tape placement. Bladder outlet obstruction and possible graft erosion should be considered.

Adult↗