Benefits of mesenchymal stem cells after partial bladder outlet obstruction

The PI3K-AKT-mTOR signaling pathway mediates the cytoskeletal remodeling and epithelial-mesenchymal transition in bladder outlet obstruction

Objective

Partial bladder outlet obstruction(pBOO) is the most common cause of lower urinary tract symptoms (LUTS) and significantly affects the quality of life. Long-term pBOO can cause changes in bladder structure and function, referred to as bladder remodeling. The pathogenesis of pBOO-induced bladder remodeling has yet to be fully understood, so effective treatment options are lacking. Our study aimed to explore how pBOO-induced bladder remodeling brings new strategies for treating pBOO.

Methods

A rat model of pBOO was established by partial ligation of the bladder neck, and the morphological changes and fibrosis changes in the bladder tissues were detected by H&E and Masson trichrome staining. Furthermore, EMT(epithelial-mesenchymal transition) related indicators and related pathway changes were further examined after TGF- β treatment of urothelial cells SV-HUC-1. Finally, the above indicators were tested again after using the PI3K inhibitor. Subsequently, RNA sequencing of bladder tissues to identify differential genes and related pathways enrichment and validated by immunofluorescence and western blotting analysis.

Results

The pBOO animal model was successfully established by partially ligating the bladder neck. H&E staining showed significant changes in the bladder structure, and Masson trichrome staining showed significantly increased collagen fibers. RNA sequencing results significantly enriched in the cytoskeleton, epithelial-mesenchymal transformation, and the PI3K-AKT-mTOR signaling pathway. Immunofluorescence and western blotting revealed EMT and cytoskeletal remodeling in SV-HUC-1 cells after induction of TGF- β and in the pBOO bladder tissues. The western blotting showed significant activation of the PI3K-AKT-mTOR signaling pathway in SV-HUC-1 cells after induction of TGF-β and in pBOO bladder tissues. Furthermore, EMT and cytoskeletal damage were partially reversed after PI3K pathway inhibition using PI3K inhibitors.

Conclusions

In the pBOO rat model, the activation of the PI3K-AKT-mTOR signaling pathway can mediate the cytoskeletal remodeling and the EMT to induce fibrosis in the bladder tissues. PI3K inhibitors partially reversed EMT and cytoskeletal damage.

Intraperitoneally Delivered Umbilical Cord Lining Mesenchymal Stromal Cells Improve Survival and Kidney Function in Murine Lupus via Myeloid Pathway Targeting

To determine the therapeutic efficacy of human umbilical cord lining mesenchymal stromal cells (CL-MSCs) (US Patent number 9,737,568) in lupus-prone MRL/lpr (Fas^lpr) mice and elucidate its working mechanisms. A total of 4 doses of (20-25) × 10⁶ cells/kg of CL-MSCs was given to 16-week-old female Fas^lpr mice by intraperitoneal injection. Three subsequent doses were given on 17 weeks, 18 weeks, and 22 weeks, respectively. Six-week-old Fas^lpr mice were used as disease pre-onset controls. Mice were monitored for 10 weeks. Mouse kidney function was evaluated by examining complement component 3 (C3) deposition, urinary albumin-to-creatinine ratio (ACR), and lupus nephritis (LN) activity and chronicity. Working mechanisms were elucidated by flow cytometry, Luminex/ELISA (detection of anti-dsDNA and isotype antibodies), and RNA sequencing. CL-MSCs improved mice survival and kidney function by reducing LN activity and chronicity and lymphocyte infiltration over 10 weeks. CL-MSCs also reduced urinary ACR, renal complement C3 deposition, anti-dsDNA, and isotype antibodies that include IgA, IgG1, IgG2a, IgG2b, and IgM. Immune and cytokine profiling demonstrated that CL-MSCs dampened inflammation by suppressing splenic neutrophils and monocytes/macrophages, reducing plasma IL-6, IL-12, and CXCL1 and stabilizing plasma interferon-γ and TNF-α. RNA sequencing further showed that CL-MSCs mediated immunomodulation via concerted action of pro-proinflammatory cytokine-induced chemokines and production of nitric oxide in macrophages. CL-MSCs may provide a novel myeloid (neutrophils and monocytes/macrophages)-targeting therapy for SLE.

Human amniotic fluid stem cells can alleviate detrusor dysfunction caused by bladder outlet obstruction in rats

The present study examined whether bladder detrusor dysfunction due to partial bladder outlet obstruction (pBOO) could be improved after the treatment of human amniotic fluid stem cells (hAFSCs). 72 female rats were grouped into sham operation, pBOO, and pBOO with hAFSCs treatment (pBOO + hAFSCs) for in vitro and in vivo studies. Bladder weight, bladder wall thickness, the ratio of collagen to smooth muscle and the levels of positive CD11b/c and HIS48 cells was significantly increased after pBOO but improved after hAFSCs treatment. Cystometries showed impaired bladder function after pBOO. Protein and mRNA levels of hypoxia inducible factor-1α, CCL2, interleukin-1β, transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), α-smooth muscle actin, collagen I and collagen III were increased at 2 and/or 6 weeks, but proteins and mRNA expressions of protein gene product 9.5 were decreased at 2 and 6 weeks after pBOO. These abnormalities were improved after hAFSCs treatment. The expressions of TGF-β1 and CTGF in cultured detrusor cells of pBOO rats were increased but were improved after hAFSCs treatment. The present results showed hAFSCs treatment could improve bladder detrusor dysfunction in pBOO rats, which may be related to the reduction of inflammatory and pro-fibrotic markers in detrusor muscle cells.

Human Urine-Derived Stem Cells Improve Partial Bladder Outlet Obstruction in Rats: Preliminary Data and microRNA-mRNA Expression Profile

Partial bladder outlet obstruction (pBOO) often results in bladder tissue inflammation and remodeling. As human urine-derived stem cells (USCs) have demonstrated therapeutic benefits, we used a rat model to investigate the effect of USCs on bladder function and explore the miRNA and gene expression profiles in bladder tissue using RNA sequencing. Eighteen rats were assigned to a sham surgery group, pBOO group, and pBOO+USC group (six biweekly treatments). Routine urodynamic monitoring, analysis of detrusor muscle strips, and pathophysiology assessments were conducted. Finally, altered miRNA and mRNA expression profiles of bladder tissue were examined using RNA sequencing and bioinformatics analysis. After USC treatment, elevated bladder compliance and maximal voiding pressure, declined end filling pressure and voided volume, and improved detrusor muscle contractility and carbachol sensitivity were found. Histology and TUNEL assay revealed reduced collagen deposition and muscle cell apoptosis in bladder tissue. The differential expression of eight miRNAs was reversed by USC treatment. Two large nodes (miR-142 and miR-9a) were identified in the miRNA-gene interaction network in the USC-treated group. The Kyoto Encyclopedia of Genes and Genomes analysis revealed enrichment of multiple significant pathways, including those involved in necroptosis and cytokine-cytokine receptor interactions. This is the first study to demonstrate the protective effect of USCs on bladder function and remodeling in pBOO rats. The miRNA and mRNA expression levels differed in the bladder of pBOO rats with and without USC treatment. Although the mechanism underlying these effects has not been fully elucidated, necroptosis and cytokine-cytokine receptor interaction-related pathways may be involved.

Differentially Expressed Genes Correlated with Fibrosis in a Rat Model of Chronic Partial Bladder Outlet Obstruction

Chronic partial bladder outlet obstruction (PBOO) is a prevalent clinical problem that may result from multiple etiologies. PBOO may be a secondary condition to various anatomical and functional abnormalities. Bladder fibrosis is the worst outcome of PBOO. However, gene alterations and the mechanism of fibrosis development after PBOO onset are not clear. Therefore, we aimed to investigate gene expression alterations during chronic PBOO. A rat model of PBOO was established and validated by a significant increase in rat bladder weight. The bladder samples were further analyzed by microarray, and differentially expressed genes (DEGs) that are more related to PBOO compared with the control genes were selected. The data showed that 16 significantly upregulated mRNAs and 3 significantly downregulated mRNAs are involved in fibrosis. Moreover, 13 significantly upregulated mRNAs and 12 significantly downregulated mRNAs are related to TGFB signaling. Twenty-two significantly upregulated mRNAs and nine significantly downregulated mRNAs are related to the extracellular matrix. The genes with differential expressions greater than four-fold included Grem1, Thbs1, Col8a1, Itga5, Tnc, Lox, Timp1, Col4a1, Col4a2, Bhlhe40, Itga1, Tgfb3, and Gadd45b. The gene with a differential expression less than a quarter-fold was Thbs2. These findings show the potential roles of these genes in the physiology of PBOO.

Current and Future Directions of Stem Cell Therapy for Bladder Dysfunction

Stem cells are capable of self-renewal and differentiation into a range of cell types and promote the release of chemokines and progenitor cells necessary for tissue regeneration. Mesenchymal stem cells are multipotent progenitor cells with enhanced proliferation and differentiation capabilities and less tumorigenicity than conventional adult stem cells; these cells are also easier to acquire. Bladder dysfunction is often chronic in nature with limited treatment modalities due to its undetermined pathophysiology. Most treatments focus on symptom alleviation rather than pathognomonic changes repair. The potential of stem cell therapy for bladder dysfunction has been reported in preclinical models for stress urinary incontinence, overactive bladder, detrusor underactivity, and interstitial cystitis/bladder pain syndrome. Despite these findings, however, stem cell therapy is not yet available for clinical use. Only one pilot study on detrusor underactivity and a handful of clinical trials on stress urinary incontinence have reported the effects of stem cell treatment. This limitation may be due to stem cell function loss following ex vivo expansion, poor in vivo engraftment or survival after transplantation, or a lack of understanding of the precise mechanisms of action underlying therapeutic outcomes and in vivo behavior of stem cells administered to target organs. Efficacy comparisons with existing treatment modalities are also needed for the successful clinical application of stem cell therapies. This review describes the current status of stem cell research on treating bladder dysfunction and suggests future directions to facilitate clinical applications of this promising treatment modality, particularly for bladder dysfunction.

Mesenchymal stem cells ameliorate partial bladder outlet obstruction-induced epithelial-mesenchymal transition type II independent of mast cell recruitment and degranulation

INTRODUCTION

Partial bladder outlet obstruction (pBOO) results in increased urinary storage pressure and significant morbidity. Increased pressure results in a sequence of programmed events: an initial inflammatory phase, smooth muscle hypertrophy, and fibrosis. Although epithelial-mesenchymal transition (EMT) and mast cell accumulation play intermediary roles in some fibrotic conditions, their role in pBOO has not yet been elucidated. Mesenchymal stem cell (MSC) therapy is emerging as a promising treatment for several conditions. It potently inhibits bladder deterioration after pBOO; however, its mechanism of action is insufficiently understood. Thus, we hypothesize that EMT type II pathway plays a significant role in pBOO, aided by the recruitment and activation of mast cells, and these are potently inhibited by MSCs.

METHODS

pBOO was surgically induced in female Sprague-Dawley rats and simultaneously treated with MSCs. Treatment effect was determined after two or four weeks and compared to untreated controls. Immunohistochemistry was used to measure markers characteristic of EMT (vimentin, collagenase, and collagen). Whole and degranulated mast cell counts were also performed.

RESULTS

pBOO resulted in an increased expression of collagenase, vimentin, and collagen. Mast cell recruitment increased proportionately to the length of bladder obstruction. MSC treatment significantly mitigated the EMT type II response, but mast cell recruitment and degranulation were unaffected.

CONCLUSIONS

Our results demonstrate the involvement of EMT type II in the pathophysiology of pBOO and confirm its mitigation with MSC treatment independent of mast cells response. The observations provide insight into the mechanism of action and have therapeutic ramifications.

Intraperitoneal administration of mesenchymal stem cells is effective at mitigating detrusor deterioration after pBOO

Partial bladder outlet obstruction (pBOO) results in bladder fibrosis that is initiated by an inflammatory cascade and the decompensation after smooth muscle hypertrophy. We have been using an animal model to develop the hypothesis that mesenchymal stem cells (MSCs) are able to mitigate this cytokine cascade and prevent bladder deterioration. We hypothesized that intraperitoneal administration of MSCs can produce the same effects as intravenously administered cells but may require higher dosing. Intraperitoneal treatment will provide insights into the mechanisms of action and may offer advantages over intravenous administration, as it will permit allow higher doses and potentially reduce systemic exposure. Rats underwent a surgical induction of pBOO and instillation of either 1 × 10⁶ or 5 × 10⁶ commercially acquired MSCs into the peritoneum. RT-PCR, immunohistochemistry, and urodynamics were used to compare treatment groups with controls. pBOO resulted in a marked, statistically significant, upregulation of inflammatory markers in the bladder, including transforming growth factor-β, hypoxia-inducible factor-1α, hypoxia-inducible factor-3α, mammalian target of rapamycin, and collagen types I and III. Moderate but inconsistent levels of downregulation were seen with 1 × 10⁶ MSCs, but excellent and reliable downregulation was seen with 5 × 10⁶ MSCs (P < 0.05). Immunohistochemistry confirmed that protein levels were affected in accordance with mRNA upregulation. Urodynamics demonstrated MSC treatment resulted in whole organ physiological benefits, as they prevented elevations in detrusor pressure. In conclusion, intraperitoneal administration of MSCs resulted in a similar effect as intravenous administration; however, this required a higher dose. This has significant implications for determining the mechanism of action and potential clinical application for human therapy.

Mesenchymal stem cell therapy inhibited inflammatory and profibrotic pathways induced by partial bladder outlet obstruction and prevented high-pressure urine storage

BACKGROUND

Partial bladder outlet obstruction (pBOO) is characterized by an initial inflammatory response that progresses to smooth muscle hypertrophy and fibrosis. Current treatment modalities carry high risk of morbidity. Mesenchymal stem cells (MSCs) are undifferentiated adult cells with reparative, immunomodulatory, and anti-inflammatory capacities. The ability of MSCs to inhibit inflammatory and profibrotic pathways in bladder cells has been recently reported.

OBJECTIVES

This study aimed to investigate the therapeutic effects of MSCs on pBOO-induced inflammatory, profibrotic signaling pathways and end-organ physiology.

MATERIALS AND METHODS

Twenty Sprague Dawley rats were randomly assigned to 5 groups: unobstructed controls, pBOO for 2 and 4 weeks, pBOO+MSCs for 2 and 4 weeks. Partial bladder outlet obstruction was surgically induced followed by intravenous injection of MSCs. Endpoint urodynamics was performed, and bladder tissue harvested for analysis. Reverse transcription real time polymerase chain reaction (RT-PCR) and immunohistochemistry were performed to study gene and protein expression of major inflammatory and profibrotic markers.

RESULTS

Partial bladder outlet obstruction resulted in an upregulation of transforming growth factor beta (TGFβ1), mothers against decapentaplegic homolog 2/3 (SMAD2/3), hypoxia inducible factor 1 alpha (HIF1α), hypoxia inducible factor 3 alpha (HIF3α), vascular endothelial growth factor (VEGF), tumor necrosis factor (TNFα), mechanistic target of rapamycin (mTOR), p70 ribosomal S6 protein kinase (p70 S6K), collagen 1 (COL1), and collagen 3 (COL3) expression in a time-dependent manner. This was coupled with a downregulation of interleukin (IL)-10 expression. Increase of bladder fibrosis was directly related to the duration of pBOO and associated with high urine storage pressure. Injected MSCs were identified in the bladder 4 weeks after therapy. The immunomodulatory effect of MSCs(defined by reduced TNFα and increased IL-10 and VEGF) was most predominant 2 weeks after therapy. Significant downregulation of profibrotic genes occurred 4 weeks after therapy. End filling pressure, hypertrophy, and fibrosis were significantly reduced after MSC therapy (P < 0.05).

DISCUSSION

Mesenchymal stem cell therapy led to a profound systematic improvement of the obstructed bladder. This included an initial anti-inflammatory response and a subsequent antifibrotic reaction. Essentially, both phases were associated with a reduction of urine storage pressure. The intravenously injected MSCs were tracked in the bladder. However, their presence in non-target organs such as the lungs, spleen, and liver was not tracked.

CONCLUSIONS

Partial bladder outlet obstruction induced significant upregulation of hypoxic, inflammatory, and profibrotic markers. Mesenchymal stem cell therapy potently inhibited these pathways and improved bladder function.