Activation of the TGF-ß1/Smads/α-SMA pathway is related to histological and functional changes in children with neurogenic bladder.

This research is to investigate the expression of the TGF-ß1/Smads/α-SMA pathway and its effect on bladder histology and function in children with neurogenic bladder (NB). The bladder specimens from 10 children with NB and 8 children with vesicoureteral junction obstruction were collected into the NB and control groups. The expression of TGF-ß1, Smad2, Smad3, Smad4, Smad6, α-SMA, fibronectin, collagen I and collagen III in bladder tissues was detected. In addition, the histological characteristics of the bladder were evaluated. A preoperative urodynamic study was performed on all children with NB. We analysed the correlations among the expression of the marker protein a-SMA in myofibroblasts, effector cells of the pathway, and bladder function parameters. Compared with those in the control group, the expression of TGF-ß1, Smad2, Smad3, Smad4, α-SMA, fibronectin, collagen I and collagen III was significantly increased in the NB group, while the expression of Smad6 was decreased (p < 0.01). HE and Masson staining in the NB group showed increased collagen levels and hypertrophy of smooth muscle cells. Children with NB had a low bladder volume ratio (BVR), low compliance (△C) and high maximum bladder pressure, low maximum flow rate, large postvoid residual volume, low bladder contraction index and low bladder voiding efficiency. The expression of α-SMA was negatively correlated with the BVR (r = - 0.7066, P = 0.0223) and △C (r = - 0.6516, P = 0.0412). We conclude that the TGF-ß1/Smads/α-SMA pathway is activated in the bladder tissue of children with NB and may be involved in the processes causing histological and functional changes.

METTL3/N6-methyladenosine/ miR-21-5p promotes obstructive renal fibrosis by regulating inflammation through SPRY1/ERK/NF-κB pathway activation.

Renal fibrosis induced by urinary tract obstruction is a common clinical occurrence; however, effective treatment is lacking, and a deeper understanding of the mechanism of renal fibrosis is needed. Previous studies have revealed that miR-21 impacts liver and lung fibrosis progression by activating the SPRY1/ERK/NF-kB signalling pathway. However, whether miR-21 mediates obstructive renal fibrosis through the same signalling pathway has not been determined. Additionally, studies have shown that N6-methyladenosine (m6 A) modification-dependent primary microRNA (pri-microRNA) processing is essential for maturation of microRNAs, but its role in the maturation of miR-21 in obstructive renal fibrosis has not yet been investigated in detail. To address these issues, we employed a mouse model of unilateral ureteral obstruction (UUO) in which the left ureters were ligated for 3, 7 and 14 days to simulate the fibrotic process. In vitro, human renal proximal tubular epithelial (HK-2) cells were transfected with plasmids containing the corresponding sequence of METTL3, miR-21-5p mimic or miR-21-5p inhibitor. We found that the levels of miR-21-5p and m6 A modification in the UUO model groups increased significantly, and as predicted, the SPRY1/ERK/NF-kB pathway was activated by miR-21-5p, confirming that miR-21-5p plays an important role in obstructive renal fibrosis by enhancing inflammation. METTL3 was found to play a major catalytic role in m6 A modification in UUO mice and drove obstructive renal fibrosis development by promoting miR-21-5p maturation. Our research is the first to demonstrate the role of the METTL3-m6 A-miR-21-5p-SPRY1/ERK/NF-kB axis in obstructive renal fibrosis and provides a deeper understanding of renal fibrosis.

The TGF-ß1 pathway is early involved in neurogenic bladder fibrosis of juvenile rats.

BACKGROUND: This study investigated whole neurogenic bladder's progression changes, as well as the expression of TGF-ß1 fibrosis pathway-related proteins in bilateral spinal nerve-amputated juvenile rats. METHODS: Sixty-four 8-week-old rats (32 bilateral L6 + S1 spinal nerve amputated and 32 sham operated) were selected. Cystometry was performed. General assessments, Masson, Sirius red, immunohistochemical staining, and western blotting of fibrosis and TGF-ß1 pathway-related proteins were conducted using bladder tissues. RESULTS: Cystometry results showed that the basal intravesical pressures and bladder capacities in nerve-amputated rats were significantly higher than those in sham-operated ones. Compared to the sham-operated groups, the bladder size and wall thickness in the nerve-amputated groups increased initially but then decreased over time. However, bladder weight continuously increased over time. Disintegration, thickening, and hypertrophy of the bladder wall were found over time in the amputated rats. Moreover, there was a significant increase in collagen III, and the ratio of collagen III/I was higher in amputated rats (P < 0.01). Finally, the expression of TGF-ß1, TGF-ßRI, Smad2, and collagen III and I increased in amputated bladder tissues, while Smad6 decreased over time. CONCLUSIONS: The main clinical features of pediatric neurogenic bladder (PNB) were detrusor paralysis and continuous intravesical pressure. Biological molecular findings are earlier than the pathophysiological findings. Therefore, early preventing bladder fibrosis by targeting TGF-ß1/Smad pathway-related proteins once knowing the PNB diagnosis might be an alternative treatment for PNB. IMPACT: The study found that the main clinical features of PNB were detrusor paralysis, continuous intravesical pressure, and increased TGF-beta/Smad signal proteins over time. The study makes contributions to the literature because it suggests biological molecular findings are earlier than the pathophysiological findings by various staining in PNB. The study investigated whole neurogenic bladder's progression changes, as well as the expression of TGF-ß1 fibrosis pathway-related proteins in the spinal nerve-injured PNB juvenile rat models, which suggests that early prevention of bladder fibrosis by targeting TGF-ß1/Smad pathway-related proteins once knowing the PNB diagnosis might be an alternative treatment for pediatric neurogenic bladder.