Serum/glucocorticoid-regulated kinase 1-targeted transient receptor potential oxalate subtype 1 regulates bladder smooth muscle cell proliferation due to bladder outlet obstruction in mice via activated T cell nuclear factor transcription factor 2.

Bladder outlet obstruction (BOO) is a type of chronic disease that is mainly caused by benign prostatic hyperplasia. Previous studies discovered the involvements of both serum/glucocorticoid-regulated kinase 1 (SGK1) and activated T cell nuclear factor transcription factor 2 (NFAT2) in the proliferation of smooth muscle cells after BOO. However, the relationship between these two molecules is yet to be explored. Thus, this study explored the specific mechanism of the SGK1-NFAT2 signaling pathway in mouse BOO-mediated bladder smooth muscle cell proliferation in vivo and in vitro. In vivo experiments were performed by suturing 1/2 of the external urethra of female BALB/C mice to cause BOO for 2 weeks. In vitro, mouse bladder smooth muscle cells (MBSMCs) were treated with dexamethasone (Dex) or dexamethasone + SB705498 for 12 h and were transfected with SGK1 siRNA for 48 h. The expression and distribution of SGK1, transient receptor potential oxalate subtype 1 (TRPV1), NFAT2, and proliferating cell nuclear antigen (PCNA) were measured by Western blotting, polymerase chain reaction, and immunohistochemistry. The relationship between SGK1 and TRPV1 was analyzed by coimmunoprecipitation. The proliferation of MBSMCs was examined by 5-ethynyl-2'-deoxyuridine and cell counting kit 8 assays. Bladder weight, smooth muscle thickness, and collagen deposition in mice after 2 weeks of BOO were examined. Bladder weight, smooth muscle thickness, the collagen deposition ratio, and the expression of SGK1, TRPV1, NFAT2, and PCNA were significantly increased in mice after 2 weeks of BOO. Compared with the control, 10 µM Dex promoted the expression of these four molecules and the proliferation of MBSMCs. After inhibiting TRPV1, only the expression of SGK1 was not affected, and the proliferation of MBSMCs was inhibited. After silencing SGK1, the expression of these four molecules and the proliferation of MBSMCs decreased. Coimmunoprecipitation suggested that SGK1 acted directly on TRPV1. In this study, SGK1 targeted TRPV1 to regulate the proliferation of MBSMCs mediated by BOO in mice through NFAT2 and then affected the process of bladder remodeling after BOO. This finding may provide a strategy for BOO drug target screening.

NLRP3/IL1ß inflammasome associated with the aging bladder triggers bladder dysfunction in female rats.

Bladder dysfunction is associated with fibrosis­-mediated aging, but the corresponding mechanism remains to be elucidated. Activation of the NACHT, LRR and PYD domains­containing protein 3 (NLRP3) inflammasome is related to chronic diseases associated with aging, including organ fibrosis. The present study aimed to explore the role of NLRP3/interleukin 1ß in aging­associated bladder dysfunction. Female Sprague­Dawley rats were divided into the following two groups (n=10 rats/group): 2­month­old group (young group) and 24­month­old group (old group). Urodynamics were performed to assess the bladder function of the rats. The histological alterations were identified using Masson's trichrome staining. The protein expression of the NLRP3 inflammasome and NAD­dependent protein deacetylase sirtuin­3, mitochondrial (SIRT3) were detected by western blot analysis, and immunohistochemistry was used to examine a senescence marker (p21) and the NLRP3 inflammasome in the bladder. The localization of the key molecule Caspase1 was determined using immunofluorescence. The voiding time was longer in the old group compared with the young group. The expression levels of SIRT3 were reduced in the bladders of the old group, while those of the NLRP3 inflammasome and the senescence marker were significantly higher in the bladders of the old group compared with the young group. Increased collagen deposition leads to chronic bladder fibrosis with increased NLRP3. In the histological examination, the bladders of the old group displayed increased collagen deposition, urothelial thinning and detrusor shrinkage compared with the young group. Tissue fibrosis and urothelial alterations are the principal causes of bladder dysfunction during aging. Downregulated SIRT3 and upregulated expression of the NLRP3 inflammasome are involved in the degradation of aging bladders. Inflamm­aging is a novel mechanism underlying bladder dysfunction.

Suture causing urethral meatus stricture: A novel animal model of partial bladder outlet obstruction.

AIMS: Open surgery is the most commonly used methodological approach for generating a partial bladder outlet obstruction (pBOO) animal model. Surgical suturing closing a part of the urethral meatus induces comparable pathophysiological changes in bladder and renal functions, but the optimum degree of obstruction that closely mimics the clinical pathology of pBOO has not been elucidated. We investigated the optimum obstruction level by performing a comprehensive time-dependent analysis of the stability and reliability of this novel animal model. METHODS: Six- to eight-week-old female BALB/c mice were divided into three groups according to the degree of urethral meatus stricture (UMS). Non-operated mice served as controls, and a pBOO model generated using the traditional method served as a positive control. A cystometric evaluation and long-term studies were performed to evaluate the validity and reliability of this novel animal model. An additional 35 mice were used to investigate the protein expression levels and histopathological features 24 h and 14 days postoperatively, respectively. RESULTS: The characteristic cystometry features in the UMS group revealed increased changes in pressure-related parameters compared with the control. The 1/3 UMS model is an optional pBOO animal model because the cystometric evaluation and histopathological studies revealed a striking resemblance between the 1/3 UMS model and the model generated using the traditional open-surgery method. CONCLUSIONS: The minimally invasive UMS model required less time and produced minimal alterations in pathophysiologically relevant processes compared with the traditional surgery model. Suturing to cause UMS produced effective and repeatable patterns in bladder function investigations in mice.

Triptolide sensitizes breast cancer cells to Doxorubicin through the DNA damage response inhibition.

Triptolide is an active component from a Chinese herb, Tripterygium wilfordii which has been applied for treating immune-related diseases over centuries. Recently, it was reported that a variety of cancer cell lines could be sensitized to DNA-damage based chemotherapy drugs in combination with Triptolide treatment. In the present study, we show that a short time exposure (3 h) to Triptolide, which did not trigger apoptosis, could specifically increase breast cancer cells sensitivity to Doxorubicin rather than other chemotherapy drugs including Paclitaxel, Fluorouracil, and Mitomycin C. Further studies revealed Triptolide downregulated ATM expression and inhibited DNA damage response to DNA double- strand breaks. Moreover, the chemosensitization effect to Doxorubicin from Triptolide was attenuated by overexpression of ATM in breast cancer cells. Our findings suggest that Triptolide specifically chemosensitizes breast cancer cells to Doxorubicin prior to apoptosis initiation through downregulating ATM expression and inhibiting DNA damage response.

Salidroside attenuates endothelial cellular senescence via decreasing the expression of inflammatory cytokines and increasing the expression of SIRT3.

OBJECTIVE: Endothelial cellular senescence is an important contributor to the endothelial dysfunction and atherosclerosis. Our previous studies suggested that salidroside (SAL) can alleviate atherosclerosis and protect endothelial cells against oxidative stress induced damage. However, the effect and mechanism of SAL on endothelial cellular senescence is still unclear. Here, we investigated the underlying mechanisms of SAL on preventing endothelial cellular premature senescence. METHODS AND RESULTS: We established a hyperhomocysteinemia (HHcy)mouse model via high methionine diet (HMD) to explore the protective effect of SAL. According to our results, the HMD elevated the concentration of serum homocysteine. HHcy induced the collagen deposition and the up-regulation of senescence markers, i.e. p16INK4A and p21CIP1, in intima-medial of aorta. In addition, SAL also inhibited the expression of CD68 and intercellular adhesion molecule 1 (ICAM1) in aorta. In senescent human umbilical vein endothelial cells (HUVECs) induced by H2O2, SAL treatment alleviated the expression of p16INK4A and p21CIP1 and reduced the activity of senescence-associated (SA)-ß-gal. CONCLUSION: our data suggested that SAL decreased the expression of inflammatory cytokines and up-regulated the expression of SIRT3, which might be the underlying mechanism of SAL on preventing endothelial cells from premature senescence.