Construction of tissue-engineered bladders using an artificial acellular nanocomposite scaffold loaded with stromal vascular fraction secretome.

Tissue engineering approaches offer promising alternative strategies for reconstructing bladder tissue; however, the low retention of transplanted cells and the possible risk of rejection limit their therapeutic efficacy. Clinical applicability is further limited by the lack of suitable scaffold materials to support the needs of various cell types. In the present study, we developed an artificial nanoscaffold system consisting of stromal vascular fraction (SVF) secretome (Sec) loaded onto zeolitic imidazolate framework-8 (ZIF-8) nanoparticles, which were then incorporated into bladder acellular matrix. This artificial acellular nanocomposite scaffold (ANS) can achieve gradient degradation and slowly release SVF-Sec to promote tissue regeneration. Furthermore, even after long-term cryopreservation, this completely acellular bladder nanoscaffold material still maintains its efficacy. In a rat bladder replacement model, ANS transplantation demonstrated potent proangiogenic ability and induced M2 macrophage polarization to promote tissue regeneration and restore bladder function. Our study demonstrates the safety and efficacy of the ANS, which can play a stem cell-like role while avoiding the disadvantages of cell therapy. Furthermore, the ANS can replace the bladder regeneration model based on cell-binding scaffold materials and has the potential for clinical application. STATEMENT OF SIGNIFICANCE: This study aimed to develop a gradient-degradable artificial acellular nanocomposite scaffold (ANS) loaded with stromal vascular fraction (SVF) secretome for rehabilitating bladders. Using various in vitro methods as well as rat- and zebrafish-based in vivo models, the developed ANS was assessed for efficacy and safety. Results indicated that the ANS achieved gradient degradation and slowly released the SVF secretome to promote tissue regeneration, even after long-term cryopreservation. Furthermore, ANS transplantation demonstrated a potent pro-angiogenic ability and induced M2 macrophage polarization to promote tissue regeneration and restore bladder function in a bladder replacement model. Our study demonstrates that ANS may replace bladder regeneration models based on cell-binding scaffold materials and have potential clinical application.

Hypoxia-Preconditioned Adipose-Derived Endothelial Progenitor Cells Promote Bladder Augmentation.

Tissue engineering technology provides an alternative for bladder reconstruction, which remains confronted with challenges, such as insufficient vascularization in regenerated bladder tissue. Short-term hypoxic preconditioning has been reported to be an effective method to enhance the angiogenic effect of stem cells. This study evaluated the effect and mechanism of hypoxia-preconditioned adipose-derived endothelial progenitor cells (hp-ADEPCs) on the vascularization and smooth muscle regeneration of tissue-engineered bladders. Rats were randomly divided into the following four groups: hp-ADEPC, ADEPC, bladder acellular matrix (BAM), and cystotomy groups. A partial cystectomy was performed to remove 50% of the bladder, which was augmented with hp-ADEPC-BAM, ADEPC-BAM, or BAM. Histological and functional assessments of the engineered neobladder were performed at 1 and 3 months after surgery, while the mechanism of hp-ADEPCs on vascularization was also investigated. Immunohistochemical analysis revealed that hp-ADEPC-BAM significantly promoted urothelium, blood vessel, smooth muscle, and nerve cell regeneration. Animals in the hp-ADEPC-BAM group exhibited higher bladder compliance and a relatively normal micturition pattern compared with the ADEPC-BAM and BAM groups. In addition, compared with ADEPCs, hp-ADEPCs promoted ERK phosphorylation activation and hypoxia-inducible factor-1α expression, thereby secreting more vascular endothelial growth factor and basic fibroblast growth factor and significantly enhancing the migration and angiogenesis abilities of rat endothelial cells. This is the first study to demonstrate that a combination of ADEPCs and BAM with short-term hypoxic preconditioning enhances angiogenesis and promotes the functional recovery of tissue-engineered bladders. Impact Statement Insufficient vascularization in regenerated bladder tissue remains a challenge for bladder tissue engineering. We successfully isolated adipose-derived endothelial progenitor cells (ADEPCs) with high proliferative potential and angiogenic properties. Hypoxic preconditioning was confirmed to effectively enhance stem cell activity. In this study, a porcine bladder acellular matrix (BAM) was established, and hypoxia-preconditioned autologous ADEPCs were simultaneously introduced for bladder reconstruction in a rat model, followed by an assessment of their feasibility and potential for bladder vascularization. For the first time, we demonstrated that hypoxic preconditioning of ADEPCs improves angiogenesis and the functional recovery of tissue-engineered bladders.

Construction of a vascularized bladder with autologous adipose-derived stromal vascular fraction cells combined with bladder acellular matrix via tissue engineering.

The formation of an effective vascular network can promote peripheral angiogenesis, ensuring an effective supply of blood, oxygen, and nutrients to an engineered bladder, which is important for bladder tissue engineering. Stromal vascular fraction cells (SVFs) promote vascularization and improve the function of injured tissues. In this study, adipose tissue-derived SVFs were introduced as an angiogenic cell source and seeded into the bladder acellular matrix (BAM) to generate a SVF-BAM complex for bladder reconstruction. The morphological regeneration and functional restoration of the engineered bladder were evaluated. In addition, we also explored the role of the Wnt5a/sFlt-1 noncanonical Wnt signaling pathway in regulating the angiogenesis of SVFs, and in maintaining the rational capability of SVFs to differentiate into vasculature in regenerated tissues. Histological assessment indicated that the SVF-BAM complex was more effective in promoting smooth muscle, vascular, and nerve regeneration than BAM alone and subsequently led to the restoration of bladder volume and bladder compliance. Moreover, exogenous Wnt5a was able to enhance angiogenesis by increasing the activity of MMP2, MMP9, and VEGFR2. Simultaneously, the expression of sFlt-1 was also increased, which enhanced the stability of the SVFs angiogenic capability. SVFs may be a potential cell source for tissue-engineered bladders. The Wnt5a/sFlt-1 pathway is involved in the regulation of autologous vascular formation by SVFs. The rational regulation of this pathway can promote neo-microvascularization in tissue-engineered bladders.

MicroRNA-133b suppresses bladder cancer malignancy by targeting TAGLN2-mediated cell cycle.

MicroRNAs (miRNAs), a group of small noncoding RNAs, are widely involved in the regulation of gene expression via binding to complementary sequences at 3'-untranslated regions (3'-UTRs) of target messenger RNAs. Recently, downregulation of miR-133b has been detected in various human malignancies. Here, the potential biological role of miR-133b in bladder cancer (BC) was investigated. In this study, we found the expression of miR-133b was markedly downregulated in BC tissues and cell lines (5637 and T24), and was correlated with poor overall survival. Notably, transgelin 2 (TAGLN2) was found to be widely upregulated in BC, and overexpression of TAGLN2 also significantly increased risks of advanced TMN stage. We further identified that upregulation of miR-133b inhibited glucose uptake, invasion, angiogenesis, colony formation and enhances gemcitabine chemosensitivity in BC cell lines by targeting TAGLN2. Additionally, we showed that miR-133b promoted the proliferation of BC cells, at least partially through a TAGLN2-mediated cell cycle pathway. Our results suggest a novel miR-133b/TAGLN2/cell cycle pathway axis controlling BC progression; a molecular mechanism which may offer a potential therapeutic target.

Identification of hub miRNA biomarkers for bladder cancer by weighted gene coexpression network analysis.

Bladder cancer (BC) is a common urinary system tumor with high aggressiveness, and it results in relatively high mortality due to a lack of precise and suitable biomarkers. In this study, we applied the weighted gene coexpression network analysis method to miRNA expression data from BC patients, and screened for network modules associated with BC progression. Hub miRNAs were selected, followed by functional enrichment analyses of their target genes for the most closely related module. These hub miRNAs were found to be involved in several functional pathways including pathway in cancer, regulation of actin cytoskeleton, PI3K-Akt signaling pathway, mitogen-activated protein kinase (MAPK) signaling pathway, Wnt signaling pathway, proteoglycans in cancer, focal adhesion and p53 signaling pathway via regulating target genes. Finally, their prognostic significance was tested using analyses of overall survival. A few novel prognostic miRNAs were identified based on expression profiles and related survival data. In conclusion, several miRNAs that were critical in BC initiation and progression have been identified in this study. These miRNAs, which may contribute to a comprehensive understanding of the pathogenesis of BC, could serve as potential biomarkers for BC prognosis or as new therapeutic targets.