Mechanism of Mechanical Trauma-Induced Extracellular Matrix Remodeling of Fibroblasts in Association with Nrf2/ARE Signaling Suppression Mediating TGF-β1/Smad3 Signaling Inhibition

Chitin-based hydrogel loaded with bFGF and SDF-1 for inducing endogenous mesenchymal stem cells homing to improve stress urinary incontinence

Nonoperative treatments for Stress Urinary Incontinence (SUI) represent an ideal treatment method. Mesenchymal stem cell (MSCs) treatment is a new modality, but there is a lack of research in the field of gynecological pelvic floor and no good method to induce internal MSC homing to improve SUI. Herein, we develop an injectable and self-healing hydrogel derived from β-chitin which consists of an amino group of quaternized β-chitin (QC) and an aldehyde group of oxidized dextran (OD) between the dynamic Schiff base linkage.it can carry bFGF and SDF-1a and be injected into the vaginal forearm of mice in a non-invasive manner. It provides sling-like physical support to the anterior vaginal wall in the early stages. In the later stage, it slowly releasing factors and promoting the homing of MSCs in vivo, which can improve the local microenvironment, increase collagen deposition, repair the tissue around urethra and finally improve SUI (Scheme 1). This is the first bold attempt in the field of pelvic floor using hydrogel mechanical support combined with MSCs homing and the first application of chitin hydrogel in gynecology. We think the regenerative medicine approach based on bFGF/SDF-1/chitin hydrogel may be an effective non-surgical approach to combat clinical SUI.

Association between oxidative balance score and urinary incontinence in females: results from the national health and nutrition examination survey in 2005-2018

PURPOSE

Oxidative stress plays a crucial role in the pathogenesis of urinary incontinence (UI). This study aimed to assess the association between the oxidative balance score (OBS) and UI in adult females in the United States.

METHODS

The study utilized data from the National Health and Nutrition Examination Survey database, spanning from 2005 to 2018. Weighted multivariate logistic regression, subgroup analyses, and restricted cubic spline regression were conducted to determine the odds ratio (OR) and 95% confidence intervals (95% CI) regarding the association between OBS and UI. Sensitivity analyses were performed to assess the robustness of the findings.

RESULTS

A total of 7304 participants were enrolled in this study. After adjusting for potential confounders, participants with lower OBS were found to have a higher likelihood of experiencing stress, urge, and mixed incontinence (OR, 0.986; 95% CI 0.975-0.998; p = 0.022; OR, 0.978; 95% CI 0.963-0.993; p = 0.004; and OR, 0.975; 95% CI 0.961-0.990; p = 0.001). Lifestyle factors were strongly associated with the prevalence and frequency of UI. The results remained consistent, and no significant interaction effects were observed in the subgroup analyses. The prevalence of three types of UI exhibited a nonlinear inverted U-shaped trend with increasing in OBS and dietary OBS (p for nonlinear < 0.05).

CONCLUSION

Among females, the higher the OBS, the lower the prevalence of UI. Therefore, dietary and lifestyle-related antioxidant therapy for females with UI should receive attention and be subject to further investigation.

Nrf2 protects against renal fibrosis induced by chronic cadmium exposure in mice

Environmental cadmium (Cd) exposure is a serious public health concern, as the kidney is the primary target for Cd exposure. The present study aimed to investigate the role and underlying mechanisms of nuclear factor erythroid-derived 2-like 2 (Nrf2) in renal fibrosis induced by chronic Cd exposure. Nrf2 knockout (Nrf2-KO) mice and their wild-type littermates (Nrf2-WT) were exposed to 100 or 200 ppm Cd in drinking water for up to 16 or 24 weeks. Following the Cd exposures, Nrf2-KO mice showed elevated urinary neutrophil gelatinase-associated lipocalin (NGAL) and BUN levels compared to Nrf2-WT mice. Masson's trichrome staining and expression of fibrosis-associated proteins revealed that more severe renal fibrosis occurred in Nrf2-KO than that in Nrf2-WT mice. Renal Cd content in the Nrf2-KO mice exposed to 200 ppm Cd was lower than that in Nrf2-WT mice, which might be a consequence of the severe renal fibrosis in the Nrf2-KO mice. Mechanistic studies showed that Nrf2-KO mice exhibited higher levels of oxidative damage, lower antioxidant levels, and more regulated cell death, apoptosis in particular, than those in Nrf2-WT mice caused by Cd exposure. In conclusion, Nrf2-KO mice were more prone to develop renal fibrosis induced by chronic Cd exposure, partially due to a weakened antioxidant, detoxification capacity and increased oxidative damage.

Collagen type Ⅰ-loaded methacrylamide hyaluronic acid hydrogel microneedles alleviate stress urinary incontinence in mice: A novel treatment and prevention strategy

Stress urinary incontinence (SUI), a chronic disease with widespread effects and an overall prevalence of up to 46% in adult women, is associated with a heavy disease burden. The clinical treatment for mild to moderate SUI is conservative, such as electrical stimulation and Kegel exercises, but the therapeutic effect is unsatisfactory, so it is imperative to seek new treatment modalities. Hydrogel microneedles (MNs) have been widely used in transdermal drug delivery because of their minimally invasive and highly biocompatible characteristics. Therefore, for the first time, we combined collagen type I with MN technology for the treatment and prevention of mild to moderate SUI.

Puerarin protects fibroblasts against mechanical stretching injury through Nrf2/TGF-β1 signaling pathway

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) is the most common form of urinary incontinence in women, which affects women's quality of life worldwide. Mechanical injury of the pelvic floor may disrupt the pelvic supportive tissues and connections via the remodeling of extracellular matrix (ECM), which is supposed to be one of the main pathological mechanisms of SUI.

METHODS

The SUI mouse model was established using vaginal distension (VD). Leak point pressure (LPP), maximum cystometric capacity (MCC), collagen, Nrf2 and TGF-β1 in the anterior vaginal wall were measured in either wild-type or Nrf2-knockout (Nrf2^-/^-) female C57BL/6 mice with or without puerarin treatment. Then, the mechanical stretching (MS) loaded on L929 cells was generated by a four-point bending device. mTGF-β1 or LY2109761 (an inhibitor of TGF-β1) was used to verify the protective effect of puerarin after Nrf2 knockdown or overexpression.

RESULTS

The collagen content of the anterior vaginal tissues in VD mice and LPP and MCC was decreased significantly. Besides, the expression levels of Nrf2, TGF-β1, collagen I and collagen III of MS group were downregulated in L929 cells. Puerarin pretreatment could reverse mechanical injury-induced collagen downregulation and Nrf2/TGF-β1 signaling inhibition. Moreover, both LY2109761 pretreatment and Nrf2 knockdown could attenuate the protective effect of puerarin in the mechanical injury-induced ECM remodeling, whereas exogenous TGF-β1 could counteract the effect of Nrf2 downregulation.

CONCLUSIONS

Puerarin protected fibroblasts from mechanical injury-induced ECM remodeling through the Nrf2/TGF-β1 signaling pathway. This might be a new strategy for the treatment of SUI.

Molecular Processes in Stress Urinary Incontinence: A Systematic Review of Human and Animal Studies

Stress urinary incontinence (SUI) is a common and burdensome condition. Because of the large knowledge gap around the molecular processes involved in its pathophysiology, the aim of this review was to provide a systematic overview of genetic variants, gene and protein expression changes related to SUI in human and animal studies. On 5 January 2021, a systematic search was performed in Pubmed, Embase, Web of Science, and the Cochrane library. The screening process and quality assessment were performed in duplicate, using predefined inclusion criteria and different quality assessment tools for human and animal studies respectively. The extracted data were grouped in themes per outcome measure, according to their functions in cellular processes, and synthesized in a narrative review. Finally, 107 studies were included, of which 35 used animal models (rats and mice). Resulting from the most examined processes, the evidence suggests that SUI is associated with altered extracellular matrix metabolism, estrogen receptors, oxidative stress, apoptosis, inflammation, neurodegenerative processes, and muscle cell differentiation and contractility. Due to heterogeneity in the studies (e.g., in examined tissues), the precise contribution of the associated genes and proteins in relation to SUI pathophysiology remained unclear. Future research should focus on possible contributors to these alterations.

Resveratrol Inhibits High Glucose-Induced H9c2 Cardiomyocyte Hypertrophy and Damage via RAGE-Dependent Inhibition of the NF-κB and TGF-β1/Smad3 Pathways

Hyperglycaemia is associated with the development of cardiac vascular disease. Resveratrol (RES) is a naturally occurring polyphenolic compound that possesses many biological properties, including anti-inflammatory properties and antioxidation functions. Our study aimed to explore the RES's protective roles on high glucose (HG)-induced H9c2 cells and the underlying mechanisms. Small-molecule inhibitors, western blotting (WB), as well as reverse-transcription PCR (RT-PCR) were employed to investigate the mechanisms underlying HG-induced damage in H9c2 cells. RES (40 μg/mL) treatment significantly alleviated HG-induced cardiac hypertrophy and cardiac dysfunction. RES abated the HG-induced increase in the levels of extracellular matrix (ECM) components and inflammatory cytokines, reducing ECM accumulation and inflammatory responses. Additionally, RES administration prevented HG-induced mitochondrion-mediated cardiac apoptosis of myocardial cells. In terms of mechanisms, we demonstrated that RES ameliorated the HG-induced overexpression of receptor for advanced glycation endproducts (RAGE) and downregulation of NF-κB signalling. Moreover, RES inhibited HG-induced cardiac fibrosis by inhibiting transforming growth factor beta 1 (TGF-β1)/Smad3-mediated ECM synthesis in cultured H9c2 cardiomyocytes. Further studies revealed that the effects of RES against HG-induced upregulation of NF-κB and TGF-β1/Smad3 pathways were similar to those of FPS-ZM1, a RAGE inhibitor. Collectively, the results implied that RES might help alleviate HG-induced cardiotoxicity via RAGE-dependent downregulation of the NF-κB and TGF-β/Smad3 pathways. This study provided evidence that RES can be developed as a promising cardioprotective drug.

Application of estrogen for the treatment of stress urinary incontinence in mice

BACKGROUND

Stress urinary incontinence (SUI) is a pervasive health tissue among women, which seriously affects the quality of life. The etiology of SUI is complex and diverse in women, with past studies having demonstrated that estrogen deficiency plays an important role in pelvic floor muscle atrophy and urethral degeneration. We comprehensively investigated the effects of estrogen in the treatment of SUI in female mice at cellular and animal levels.

METHODS

L929 fibroblasts mechanical injury model was established by four-point bending device, and SUI mouse model was established by vaginal dilation method commonly used to simulate labor injury. After estrogen treatment, the expressions of Collagen I, Collagen III, Elastin, TIMP-1, TIMP-2, MMP-2, and MMP-9 were detected, the leak point pressure (LPP) and abdominal leak point pressure (ALPP) of mice in each group were detected, and both the effect of estrogen on extracellular matrix remodeling of mouse urethra and anterior vaginal wall was observed from the histological level.

RESULTS

The results revealed that an appropriate amount of estrogen can promote the expression of Collagen I, Collagen III, Elastin, TIMP-1, and TIMP-2, decrease the expression of MMP-2 and MMP-9, and maintain the dynamic balance of MMPs/TIMPs at both cellular and animal levels. Meanwhile, we determined that estrogen can increase the LPP and ALPP values of SUI mice. The collagen fibers' content in the mice treated with estrogen was significantly greater than in the control group mice.

CONCLUSIONS

The estrogen may alleviate the symptoms of SUI by reconstituting ECM, thus laying a solid foundation for further exploration of estrogen therapy.

Dimethyl fumarate ameliorates stress urinary incontinence by reversing ECM remodeling via the Nrf2-TGF-β1/Smad3 pathway in mice

INTRODUCTION AND HYPOTHESIS

Mechanical trauma and oxidative injury are involved in the pathogenesis of stress urinary incontinence (SUI), and oxidative stress (OS) is considered a potential therapeutic target. The antioxidant properties of dimethyl fumarate (DMF), a potent activator of Nrf2, have been highlighted recently. We therefore predicted that DMF might have therapeutic effects on mechanical trauma-induced SUI.

METHODS

The SUI mice model was established by vaginal distension (VD). Leak point pressure (LPP), serum OS biomarkers, cell proliferation and apoptosis, collagen, elastin, matrix metalloproteinases (MMP), Nrf2, the TGF-β1/Smad3 signaling pathway, and the associated tissue growth factors in the anterior vaginal wall were measured in either wild-type or Nrf2-knockout (Nrf2^-/^-) female C57BL/6 mice.

RESULTS

The results showed that DMF improved the VD-induced LPP reduction, alleviated oxidative injury, stimulated cell proliferation and inhibited apoptosis in the anterior vaginal wall tissue of mice. Moreover, DMF treatment reduced the hydrolysis of ECM proteins by MMP2 and MMP9. The above effects may be mediated by a series of tissue growth factors, including α-SMA, PAI-1, and TIMP-2, with the TGF-β1/Smad3 signaling pathway as the core regulatory mechanism. In further study, Nrf2^-/^- mice were used to replicate the SUI model. And the difference is that DMF failed to reactivate the TGF-β1/Smad3 pathway, nor did it improve LPP.

CONCLUSIONS

Dimethyl fumarate can ameliorate urethra closure dysfunction in the VD-induced SUI mice model, and the therapeutic effect of DMF is mediated by the Nrf2-dominated antioxidant system and its downstream TGF-β1/Smad3 signaling pathway.

Nampt promotes fibroblast extracellular matrix degradation in stress urinary incontinence by inhibiting autophagy

Stress urinary incontinence (SUI) is defined as involuntary urinary leakage happening in exertion. Nicotinamide phosphoribosyltransferase (Nampt) is seldom researched in the pathogenesis of SUI. Accordingly, the current study set out to elucidate the role of Nampt in SUI progression. Firstly, we determined Nampt expression patterns in SUI patients and rat models. In addition, fibroblasts were obtained from the anterior vaginal wall tissues of non-SUI patients and subjected to treatment with different concentrations of interleukin-1β (IL-1β), followed by quantification of Nampt expressions in fibroblasts. Subsequently, an appropriate concentration of IL-1β was selected to treat anterior vaginal wall fibroblasts. Nampt was further silenced in IL-1β-treated fibroblasts to assess the role of Nampt in autophagy and extracellular matrix (ECM) degradation. Lastly, functional rescue assays were carried out to inhibit autophagy and evaluate the role of autophagy in the mechanism of Nampt modulating IL-1β-treated fibroblast ECM degradation. It was found that Nampt was highly-expressed in SUI patients and rat models and IL-1β-treated fibroblasts. On the other hand, Nampt silencing was found to suppress ECM degradation and promote SUI fibroblast autophagy. Additionally, inhibition of autophagy attenuated the inhibitory effects of Nampt silencing on SUI fibroblast ECM degradation. Collectively, our findings revealed that Nampt was over-expressed in SUI, whereas Nampt silencing enhanced SUI fibroblast autophagy, and thereby inhibited ECM degradation.

Poricoic acid A induces apoptosis and autophagy in ovarian cancer via modulating the mTOR/p70s6k signaling axis

Due to the high mortality and rapid disease progression, ovarian cancer remains one of the most common malignancies threatening the health of women. The present study was conducted to explore the anticancer effects and the underlying mechanisms of poricoic acid A (PAA), the main components of Poria cocos, on ovarian cancer. We investigated the anticancer effects of different concentrations of PAA in the SKOV3 cell line. Cell viability and proliferation were examined by CCK-8 assay. Cellular migration and invasion were assessed by the scratch and Transwell migration assays, respectively. The effect of PPA on cell apoptosis was measured by flow cytometry and caspase-3/8/9 colorimetric assay. Western blot was performed to detect protein level changes related to apoptosis and mTOR signaling pathways. The in vivo anticancer effect of PAA was evaluated using xenograft tumorigenesis model in nude mice. Our results showed that PAA suppressed SKOV3 cellular viability, migration, and invasion in a dosage-dependent manner. Flow cytometry results demonstrated PAA treatment could induce SKOV3 cell apoptosis. In addition, increased ratio of LC3-II/LC3-I (a marker for autophagosome formation) was observed after PAA treatment, as well as inhibition of m-TOR and p70s6k phosphorylation. In nude mice, PAA treatment reduced the xenograft tumor weight by 70% (P<0.05). In conclusion, our data suggested that PAA induced apoptosis and autophagy in ovarian cancer via modulating the mTOR/p70s6k signaling axis.

Nrf2 activation is involved in osteogenic differentiation of periodontal ligament stem cells under cyclic mechanical stretch

During orthodontic treatment, mechanical stretch serves a crucial function in osteogenic differentiation of periodontal ligament stem cells (PDLSCs). Up-regulated reactive oxygen species (ROS) level is a result of cyclic mechanical stretch in many cell types. Nuclear factor erythroid-2-related factor-2 (Nrf2) is a master regulator in various antioxidants expression. However, it is not known whether cyclic mechanical stretch could induce the ROS generation in PDLSCs and whether Nrf2 participated in this process. The present study was aimed to investigate the role of Nrf2 in PDLSCs under cyclic mechanical stretch. Our results showed that cyclic mechanical stretch increased ROS level and the nuclear accumulation of Nrf2 during osteoblast differentiation. Knocking down Nrf2 by siRNA transfection increased ROS formation and suppressed osteogenic differentiation in PDLSCs. T-BHQ, a Nrf2 activator, promoted the osteogenic differentiation in PDLSCs under cyclic mechanical stretch, and improved the microstructure of alveolar bone during orthodontic tooth movement in rats by employing micro-CT system. Taken together, Nrf2 activation was involved in osteogenic differentiation under cyclic mechanical stretch in PDLSCs. T-BHQ could promote the osteogenic differentiation in vitro and in vivo, suggesting a promising option for the remodeling of the alveolar bone during orthodontic tooth movement.

Small extracellular vesicles secreted by vaginal fibroblasts exert inhibitory effect in female stress urinary incontinence through regulating the function of fibroblasts

Stress urinary incontinence (SUI) is a common condition in women and associated with extra-cellular matrix (ECM) reconstruction, which is mainly regulated by fibroblasts. However, the underlying mechanism remains obscure. Small extracellular vesicles (sEVs) play fundamental biological roles in various cellular functions. Some studies suggested that the sEVs were involved in the metabolism of ECM and the function of fibroblasts. The purpose of our study was to investigate the effect of sEVs secreted by vaginal fibroblasts on the pathogenesis of SUI. We showed that the fibroblasts of female anterior vaginal wall secreted sEVs. Moreover, fibroblasts of females with SUI had significantly elevated secretion of sEVs. The collagen contents, proliferation and migration capacity of fibroblasts were decreased when fibroblasts were co-cultured with fibroblasts-derived sEVs (fibroblast-sEVs) from SUI patients. Proteomic analysis revealed that fibroblast-sEVs contained various differentially expressed proteins including TIMP2, TGF-β and ABCC4, which were involved in signaling pathways of fibroblasts regulation. Therefore, we suggested that fibroblast-sEVs contributed to the pathogenesis of SUI through various proteins including TIMP2, TGF-β and ABCC4.

Effects of mechanical trauma on the differentiation and ArfGAP3 expression of C2C12 myoblast and mouse levator ani muscle

INTRODUCTION AND HYPOTHESIS

Severe mechanical injury or inadequate repair of the levator ani muscle (LAM) is a key contributor to the development of pelvic floor dysfunction (PFD). We explored the effects of mechanical stress on myoblasts and LAM at the cellular and animal level and the possible mechanism of PFD induced by mechanical trauma.

METHODS

A C2C12 cell mechanical injury model was established with a four-point bending device, and a LAM injury mouse model was established via vaginal distention and distal traction, a common way of simulating the birth injury. The cells were divided into control, 1333 μ strain for 4-h cyclic mechanical strain (CMS), 1333 μ strain for 8-h CMS, and 5333 μ strain for 4-h CMS groups. Mice were divided into control and injury groups. After treatment, mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) levels, indicators of oxidative damage, cell apoptosis, muscle and cell morphology, cell differentiation, and expression of adenosine diphosphate (ADP)-ribosylation factor GTPase activating protein 3 (ArfGAP3) were detected.

RESULTS

5333 μ strain for 4-h CMS loading could induce myoblast injury with a reduction of ΔΨm, increased ROS levels, aggravation of oxidative damage-associated proteins NADPH oxidase 2 (NOX2) and xanthine oxidase (XO), and an increased apoptosis rate of C2C12 cells. At the same time, the injury CMS loading can promote the differentiation of myoblasts and increase the expression of ArfGAP3, a factor regulating intracellular transport. Mechanical trauma could also lead to the oxidative damage of LAM, indicated by 8-hydroxy-2'-deoxyguanosine(8-OHdG), NOX2 and XO protein accumulation, and increase the expression of ArfGAP3 in LAM.

CONCLUSIONS

Oxidative stress caused by mechanical trauma induces dysfunction and damage repairing of LAM and C2C12 myoblast, and ArfGAP3 may promote the repairing process.

Paeonol induces cytoprotective autophagy via blocking the Akt/mTOR pathway in ovarian cancer cells

Paeonol (Pae), a phenolic acid compound isolated from the Moutan Cortex, was previously demonstrated to exert multiple anticancer effects. The rational control of autophagy has been considered a potential treatment strategy for epithelial ovarian cancer. However, whether Pae induces autophagy and the relationship between its antitumour activities and autophagy in epithelial ovarian cancer are still unclear. In this study, we found that Pae induced not only antiproliferation activity and apoptosis but also autophagy, and complete autophagic flux was observed in A2780 and SKOV3 cells. In addition, combination treatment with Pae and an autophagy inhibitor (3-methyladenine and hydroxychloroquine) showed significant synergetic effects on inhibiting cell viability and promoting apoptosis in vitro and in the A2780 xenograft model, without severe side effects, which was often had by cisplatin. These results indicate that autophagy induced by Pae has a cytoprotective role in both A2780 and SKOV3 cells. Mechanistically, we found that Pae inhibited the protein kinase B(Akt)/mammalian target of rapamycin (mTOR) pathway. Furthermore, when combined with the inhibitors MK2206 and rapamycin to inhibit Akt and mTOR kinase activity, Pae-induced autophagy was increased. Taken together, our results demonstrate that Pae induced cytoprotective autophagy by inhibiting the Akt/mTOR pathway in ovarian cancer cells. Thus, the strategy of combining Pae with an autophagy inhibitor to block Akt/mTOR-dependent autophagy could enhance the antitumour activity of Pae and warrants further application for the treatment of ovarian cancer.

Yellow Wine Polyphenolic Compounds prevents Doxorubicin-induced cardiotoxicity through activation of the Nrf2 signalling pathway

Doxorubicin (DOX) is considered as the major culprit in chemotherapy‐induced cardiotoxicity. Yellow wine polyphenolic compounds (YWPC), which are full of polyphenols, have beneficial effects on cardiovascular disease. However, their role in DOX‐induced cardiotoxicity is poorly understood. Due to their antioxidant property, we have been suggested that YWPC could prevent DOX‐induced cardiotoxicity. In this study, we found that YWPC treatment (30 mg/kg/day) significantly improved DOX‐induced cardiac hypertrophy and cardiac dysfunction. YWPC alleviated DOX‐induced increase in oxidative stress levels, reduction in endogenous antioxidant enzyme activities and inflammatory response. Besides, administration of YWPC could prevent DOX‐induced mitochondria‐mediated cardiac apoptosis. Mechanistically, we found that YWPC attenuated DOX‐induced reactive oxygen species (ROS) and down‐regulation of transforming growth factor beta 1 (TGF‐β1)/smad3 pathway by promoting nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) nucleus translocation in cultured H9C2 cardiomyocytes. Additionally, YWPC against DOX‐induced TGF‐β1 up‐regulation were abolished by Nrf2 knockdown. Further studies revealed that YWPC could inhibit DOX‐induced cardiac fibrosis through inhibiting TGF‐β/smad3‐mediated ECM synthesis. Collectively, our results revealed that YWPC might be effective in mitigating DOX‐induced cardiotoxicity by Nrf2‐dependent down‐regulation of the TGF‐β/smad3 pathway.

Effect of integrin β1 in the treatment of stress urinary incontinence by electrical stimulation

The aim of the present study was to investigate the protective effect of integrin β1 in the treatment of stress urinary incontinence (SUI) by electrical stimulation, and the underlying mechanisms by which electrical stimulation regulates the collagen metabolism of female vaginal wall fibroblasts (FVWFs). FVWFs obtained from the vaginal wall tissue of patients with (Ingelman-Sundberg scale; grade II, n=8; grade III, n=10) or without (n=8) SUI during gynecological operations were isolated by enzymatic digestion and subsequently identified by immunocytochemistry. Following this, cultured FVWFs were treated with an inhibitor of integrin β1, recombinant human integrin β1 and electrical stimulation (100 mv/mm, 2 h, 20 Hz), followed by total mRNA and protein extraction. mRNA and protein expression levels of integrin β1, transforming growth factor (TGF)-β1 and collagen (COL) I and III in FVWFs were quantified by reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis respectively. Integrin β1, TGF-β1 and COL I and III expression levels were decreased in patients with SUI compared with healthy controls, and the grade III group had lower levels than the grade II group. Following electrical stimulation treatment, the expression levels of TGF-β1, COL I and III were enhanced in the grade II group, but not in the grade III group. Nevertheless, the inhibitor of integrin β1 reduced the protective effect of electrical stimulation in the grade II group. In addition, electrical stimulation combined with recombinant human integrin β1 could also protect cells from SUI in the grade III group. The present study provides evidence for the increased degradation of the extracellular matrix and integrin β1 in the vaginal wall tissues of patients with SUI, and the protective effect of electrical stimulation against SUI via integrin β1. These results provide a novel mechanism for the treatment of SUI using electrical stimulation.

Electrical stimulation activates calpain 2 and subsequently upregulates collagens via the integrin β1/TGF-β1 signaling pathway

Stress urinary incontinence (SUI) is a public health issue attributed to weakened pelvic supporting tissues. Electrical stimulation (ES) is one of the first-line conservative treatments for SUI. However, the underlying mechanism of ES in the treatment of SUI is not clear. Here, we show that ES suppresses cell apoptosis and upregulates collagen expression by functioning as a cell growth inducer to activate the calpain 2/talin 1/integrin β1/transforming growth factor (TGF)-β1 axis. Specifically, ES promoted Ca²⁺ to flow into the cytoplasm through the calcium channel, Cav 3.2, thereby activating calpain 2. Then, the activated calpain 2 cleaved talin 1, which induced the activation of integrin β1 and upregulated the TGF-β1-mediated transcription of collagen I and III. Notably, blocking Cav 3.2 suppressed calcium influx and inhibited the activation of downstream proteins. Furthermore, the knockdown of calpain 2 resulted in the reduction of cleaved talin 1, and the shRNA-integrin β1 treatment downregulated the level of activated integrin β1 and the expression of TGF-β1-induced collagen I and III. An association of the ES-modulated collagen I and III upregulation with the therapeutic effect of the ES-Ca²⁺/calpain 2/talin 1/integrin β1/TGF-β1 axis was demonstrated in mouse fibroblast and mouse SUI models established through vaginal distension (VD). This outcome provides insight into clinical diagnosis and treatment.

Protective Role of Nuclear Factor Erythroid-2-Related Factor 2 against Mechanical Trauma-Induced Apoptosis in a Vaginal Distension-Induced Stress Urinary Incontinence Mouse Model

Apoptosis and oxidative damage are involved in the pathogenesis and progression of stress urinary incontinence (SUI). Our previous results indicate that cell apoptosis and oxidative damage increase in a mouse model of mechanical injury-induced SUI and in fibroblasts treated with excessive mechanical strain. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a well-characterized global antioxidant gene inducer that can reduce oxidative damage and apoptosis. Therefore, we predicted that Nrf2 may have a protective role in mechanical trauma-induced SUI. To test this hypothesis, a mouse model of vaginal distension- (VD-) induced SUI was established. Leak point pressure (LPP); levels of apoptosis, apoptosis-related proteins, and peroxidation products; and the activities of antioxidative proteins in the anterior vaginal wall were measured in wild-type (Nfe2l2^+/+) C57BL/6 mice and Nrf2-knockout mice (Nfe2l2^−/−). The results showed that Nrf2 knockout aggravated VD-induced reduction in LPP, increase in cell apoptosis and peroxidation product levels, decrease in antioxidative protein activities, and alterations in apoptosis-related protein levels in the vaginal walls of mice. To further confirm the role of Nrf2 in mechanical trauma-induced apoptosis and SUI, VD was performed on mice overexpressing Nrf2 via in vivo transfection of LV-Nfe2l2. The results showed that Nrf2 overexpression significantly alleviated VD-induced abnormalities in the anterior vaginal wall. Taken together, our data suggested that Nrf2 is a potential protective factor in mechanical trauma-induced apoptosis in a mouse model of SUI. Antioxidative therapy may be a promising treatment for mechanical trauma-related SUI.

Effects of the isothiocyanate sulforaphane on TGF-β1-induced rat cardiac fibroblast activation and extracellular matrix interactions

An important step in many pathological conditions, particularly tissue and organ fibrosis, is the conversion of relatively quiescent cells into active myofibroblasts. These are highly specialized cells that participate in normal wound healing but also contribute to pathogenesis. These cells possess characteristics of smooth muscle cells and fibroblasts, have enhanced synthetic activity secreting abundant extracellular matrix components, cytokines, and growth factors, and are capable of generating contractile force. As such, these cells have become potential therapeutic targets in a number of disease settings. Transforming growth factor β (TGF-β) is a potent stimulus of fibrosis and myofibroblast formation and likewise is an important therapeutic target in several disease conditions. The plant-derived isothiocyanate sulforaphane has been shown to have protective effects in several pathological models including diabetic cardiomyopathy, carcinogenesis, and fibrosis. These studies suggest that sulforaphane may be an attractive preventive agent against disease progression, particularly in conditions involving alterations of the extracellular matrix and activation of myofibroblasts. However, few studies have evaluated the effects of sulforaphane on cardiac fibroblast activation and their interactions with the extracellular matrix. The present studies were carried out to determine the potential effects of sulforaphane on the conversion of quiescent cardiac fibroblasts to an activated myofibroblast phenotype and associated alterations in signaling, expression of extracellular matrix receptors, and cellular physiology following stimulation with TGF-β1. These studies demonstrate that sulforaphane attenuates TGF-β1-induced myofibroblast formation and contractile activity. Sulforaphane also reduces expression of collagen-binding integrins and inhibits canonical and noncanonical TGF-β signaling pathways.

The deregulation of STIM1 and store operative calcium entry impaired aortic smooth muscle cells contractility in aortic medial degeneration

Background: Microarray analysis of clinical aortic samples suggested a potential role for stromal interaction molecule 1 (STIM1) in the modulation of aortic medial degeneration (AMD), despite the uncertainty about STIM1 in normal aortic smooth muscle cells (ASMCs). Here, we aimed to explore changes in STIM1 expression in AMD, and the possible mechanisms. Methods: An AMD model was established using auto-delivery of angiotensin II (Ang II) into ApoE^-/- mice. We assessed the effects of SKF96365, a STIM1 inhibitor, in AMD model and in vitro cultured ASMCs. Elastic van Gieson (EVG) staining was used to visualize elastic fiber injury. Mitochondria changes were viewed by TEM. Cytoplasmic calcium was quantified by measuring fluo-4 staining in a flow cytometer. Mechanical stretching device was used to mimic stretching that ASMCs experience in vivo Cell apoptosis was determined by using Annexin V/propidium iodide (PI) staining. The expression of STIM1, contractile related proteins (α-smooth muscle actin (α-SMA), myosin light chain (MLC)), endoplasmic reticulum (ER) stress-related proteins (CHOP, activating transcription factor 6 (ATF-6)) and smad2/3 were assessed by Western blotting, immunohistochemistry (IHC), and immunofluorescence (IF). Results: SKF96365 exacerbated aortic injury in the AMD model. SKF96365 reduced cytoplasmic calcium concentration in ASMCs, caused mitochondrial swelling, and elevated the expression of ATF-6 and CHOP. SKF96365 decreased the expression of MLC and α-SMA in ASMCs, causing them to be vulnerable to mechanical stretch. SKF96365 suppressed smad2/3 activation after treatment with transforming growth factor (TGF) β1 (TGFβ1). Conclusions: STIM1 is indispensable in ASMCs. Interfering with STIM1 exaggerated the AMD process by modulating the expression of contractile proteins, inducing ER stress in ASMCs.

Effects of RSC96 Schwann Cell-Derived Exosomes on Proliferation, Senescence, and Apoptosis of Dorsal Root Ganglion Cells In Vitro

Background

Stress urinary incontinence is a common condition in women and can be associated with peripheral nerve injury. Exosomes. derived from Schwann cells, can enhance the regeneration of axons of the peripheral nervous system. This study aimed to investigate the effects of RSC96 Schwann cell-derived exosomes in a novel in vitro model of dorsal root ganglion (DRG) cell injury induced by cyclic mechanical strain (CMS).

Material/Methods

RSC96 Schwann cells and DRG cells were cultured in vitro. CMS in DRG cells involved mechanical stretch trauma with 5333 μ strain. ExoQuick-TC polymer was used to precipitate exosomes from RSC96 Schwann cell culture medium and identified by nanoparticle tracking analysis, electron microscopy, and Western blot for detection of CD9 and tumor susceptibility gene 101 (Tsg101) protein. Cultured DRG cells were treated with RSC96 Schwann cell-derived exosomes, followed by measurement of cell viability, proliferation, senescence, and apoptosis using the cell counting kit-8 (CCK-8) assay, senescence-associated beta-galactosidase (SA-β-gal) staining, and Hoechst 33258 (blue) fluorescence nucleic acid staining using flow cytometry.

Results

Mechanical stretch with 5333 μ strain for 8 hours at 1 Hz decreased the activity of cultured DRG cells. RSC96 Schwann cell-derived exosomes promoted cell proliferation and significantly inhibited apoptosis and senescence of DRG cells following injury induced by CMS.

Conclusions

An in vitro model of DRG cell injury induced by CMS, showed that RSC96 Schwann cell-derived exosomes had a protective effect. The effects of Schwann cell-derived exosomes on peripheral nerve injury, including in stress urinary incontinence, require future in vivo studies.

Melatonin protects H9c2 cells against ischemia/reperfusion‑induced apoptosis and oxidative stress via activation of the Nrf2 signaling pathway

Melatonin can protect against cardiac ischemia/reperfusion (I/R) injury in models in vitro and in vivo by regulating oxidative stress and apoptosis; however, the precise molecular mechanisms involved remain unclear. Nuclear factor erythroid 2‑related factor 2 (Nrf2) is a transcription factor, which has been associated with the regulation of oxidative stress by translocating to the nucleus. Therefore, the present study investigated whether activation of the Nrf2 signaling pathway may be responsible for the protective effects of melatonin on I/R‑injured cardiomyocytes. In the present study, H9c2 cells were subjected to simulated I/R (SIR) injury and pretreated with melatonin and/or Nrf2 small interfering RNA (siRNA). Cell viability was detected via Cell Counting kit‑8 assay, apoptosis was examined by caspase‑3 cleavage and activity analysis; oxidative stress levels were determined by specific activity analysis assays. In the present study, it was observed that SIR induced significant increases in apoptosis and oxidative stress, and enhanced Nrf2 expression within H9c2 cells. Pretreatment with melatonin partially reversed these alterations and promoted Nrf2 nuclear translocation. Transfection with Nrf2 siRNA inhibited the protective effects of melatonin on SIR‑induced H9c2 cells. These results indicated that melatonin may protect H9c2 cells against I/R injury by reducing apoptosis and oxidative stress; this effect may be mediated via activation of the Nrf2 signaling pathway. Collectively, the results of the present study may suggest melatonin as a potential therapeutic agent against cardiac I/R injury.