Increased extracellular matrix stiffness regulates myofibroblast transformation through induction of autophagy-mediated Kindlin-2 cytoplasmic translocation.

The extracellular matrix (ECM) mechanical properties regulate biological processes, such as fibroblast-myofibroblast transformation (FMT), which is a crucial component in pelvic organ prolapse (POP) development. The 'Kindlin-2' protein, expressed by fibroblasts, plays an important role in the development of the mesoderm, which is responsible for connective tissue formation; however, the role of Kindlin-2 in FMT remains to be explored. In this study, we aimed to explore the role of Kindlin-2 in FMT as it relates to POP. We found that ECM stiffness induces autophagy to translocate Kindlin-2 to the cytoplasm of L929 cells, where it interacts with and degrades MOB1, thereby facilitating Yes-associated protein (YAP) entry into the nucleus and influencing FMT progression. Stiffness-induced autophagy was inhibited when using an autophagy inhibitor, which blocked the translocation of Kindlin-2 to the cytoplasm and partially reversed high-stiffness-induced FMT. In patients with POP, we observed an increase in cytoplasmic Kindlin-2 and nuclear YAP levels. Similar changes in vaginal wall-associated proteins were observed in a mouse model of acute vaginal injury. In conclusion, Kindlin-2 is a key gene affecting ECM stiffness, which regulates FMT by inducing autophagy and may influence the development of POP.

A tert-Butyldiphenylsilyl-Containing Polyimide-Based Chemosensor for Sequential Detection of Fluoride Ions and Trace Water in Organic Solvents.

A tert-butyldiphenylsilyl-containing polyimide (PI-OSi) has been established as a colorimetric and ratiometric chemosensor for rapid detecting fluoride ions (F-). The UV-vis absorbance ratio value (A322/A288) of PI-OSi in a DMF solution displays a wide linear range change to F- concentrations with a detection limit (DL) value of 2.13 µM. Additionally, adding incremental amounts of F- to a DMF solution of PI-OSi shows an immediate color change to yellow and finally to green from colorless. More interestingly, the resulting PI-OSi plus F- system (PI-OSi·F) could detect trace water in DMF. The A292/A322 value of PI-OSi·F almost linearly increases with low water content, which suggests convenient quantitative sensing of trace water content in DMF. The DL value of PI-OSi·F for sensing water in DMF is determined to be 0.00149% (v/v). The solution color of PI-OSi·F returns to colorless when the water content increases, indicating that PI-OSi·F can conveniently estimate water content in DMF by naked-eye detection. The detection mechanisms confirmed by an 1H NMR study and a DFT calculation involve a F--induced desilylation reaction of PI-OSi to form phenolate anion followed by protonation with trace water. Finally, PI-OSi film was fabricated for the colorimetric detection of F- and water in CH3CN.

Estrogen inhibits the differentiation of fibroblasts induced by high stiffness matrix by enhancing DNMT1 expression.

INTRODUCTION AND HYPOTHESIS: Pelvic organ prolapse(POP) is a multifactorial connective tissue disorder caused by damage to the supporting structures of the pelvic floor. Evidence from several studies suggests that anterior vaginal wall stiffness is higher in patients with POP, but the mechanisms involved remain unknown. METHODS: Tissue from the anterior vaginal wall of patients with POP or other benign diseases was obtained. The modulus of elasticity of the anterior vaginal wall was measured using a microindenter. Cells were cultured in vitro on acrylamide gels of different stiffness and treated with DNMT1 inhibitor, microtubule polymerisation inhibitor and estrogen. Western blot or immunohistochemical staining was performed to detect DNA Methyltransferase 1, α-smooth muscle actin(α-SMA) expression, and connective tissue growth factor(CTGF) expression. CONCLUSION: Estrogen can inhibit high stiffness matrix-induced fibroblast differentiation, by enhancing DNMT1 expression. This study may help to elucidate the complex crosstalk between fibroblasts and their surrounding matrix under healthy and pathological conditions and provide new insights into the options for material-related therapeutic applications.

Ferrostatin-1 alleviates the damage of C2C12 myoblast and mouse pelvic floor muscle induced by mechanical trauma.

Ferroptosis is a special form of regulated cell death, which is reported to play an important role in a variety of traumatic diseases by promoting lipid peroxidation and devastating cell membrane structure. Pelvic floor dysfunction (PFD) is a kind of disease affecting the quality and health of many women's lives, which is closely related to the injury of the pelvic floor muscle. Clinical findings have discovered that there is anomalous oxidative damage to the pelvic floor muscle in women with PFD caused by mechanical trauma, but the specific mechanism is still unclear. In this study, we explored the role of ferroptosis-associated oxidative mechanisms in mechanical stretching-induced pelvic floor muscle injury, and whether obesity predisposed pelvic floor muscle to ferroptosis from mechanical injury. Our results, in vitro, showed that mechanical stretch could induce oxidative damage to myoblasts and trigger ferroptosis. In addition, glutathione peroxidase 4 (GPX4) down-regulation and 15-lipoxygenase 1(15LOX-1) up-regulation exhibited the same variational characteristics as ferroptosis, which was much more pronounced in palmitic acid (PA)-treated myoblasts. Furthermore, ferroptosis induced by mechanical stretch could be rescued by ferroptosis inhibitor (ferrostatin-1). More importantly, in vivo, we found that the mitochondria of pelvic floor muscle shrank, which were consistent with the mitochondrial morphology of ferroptosis, and GPX4 and 15LOX-1 showed the same change observed in cells. In conclusion, our data suggest ferroptosis is involved in the injury of the pelvic floor muscle caused by mechanical stretching, and provide a novel insight for PFD therapy.

Restoration of NAD+ homeostasis protects C2C12 myoblasts and mouse levator ani muscle from mechanical stress-induced damage.

Excessive mechanical traction damages the levator ani muscle (LAM), increasing the incidence of pelvic floor dysfunction (PFD). In this study, we explored the effects of oxidized nicotinamide adenine dinucleotide (NAD+) on the damage to both muscle cells and LAM tissue induced by mechanical stress (MS) at the cellular and animal levels. The cell damage model was established using a four-point bending system. The LAM damage model was established using vaginal distention and traction. Exogenous addition of PJ34, an inhibitor of poly (ADP-ribose) polymerase-1 (PARP-1), and the nicotinamide mononucleotide (NMN) precursor of NAD+ increased NAD+ levels. ATP content and mitochondrial membrane potential were measured to assess mitochondrial function. NAD+ levels, cell viability, and PARP-1 activity were detected using commercial kits. DNA damage in cells was detected with immunofluorescence staining, and LAM damage was detected with tissue TUNEL staining. PARP-1 activity and DNA damage of LAM were detected by immunohistochemistry. A small amount of DNA damage and PARP-1 activation did not affect NAD+ levels, while excessive DNA damage and PARP-1 activation led to an imbalance of NAD+ homeostasis. Furthermore, increasing NAD+ levels in vivo and in vitro could rescue mitochondrial dysfunction and damage to both muscle cells and LAM tissue induced by MS. In conclusion, MS can induce damage to both C2C12 cells and LAM tissue. Restoring NAD+ homeostasis can rescue this damage by improving mitochondrial function.

Protective effect and potential mechanism of Schwann cell-derived exosomes on mechanical damage of rat dorsal root ganglion cells.

BACKGROUND: Pudendal nerve (PN) injury was one of the most important pathogenesis of stress urinary incontinence (SUI). Schwann cell (SC)-derived exosomes could promote axonal regeneration. Wnt protein could significantly promote axonal regeneration and participate in the regulation of proliferation and differentiation of neural stem cells. Therefore, we sought to determine whether SCs-derived exosomes might also protect against damaged dorsal root ganglion cells (DRGs) through the Wnt/ß-catenin pathway. MATERIAL AND METHODS: The DRGs injury model was fabricated using a four-point bending system. The exosomes were separated from the SCs supernatant. XAV939, which was a small molecule inhibitor, was used to inhibit the Wnt/ß-catenin pathway. Next, Cell Counting Kit-8 (CCK8) kit was used to detect cell activity. We evaluated the proliferative activity of DRG cells using the cell cycle and apoptosis detection kit. We assessed the cell apoptotic rates through the Annexin V/PE double staining. Finally, we detect the expression of downstream proteins of Wnt/ß-catenin pathway in DRG cells using western blotting. RESULTS: SC-derived exosomes had protective effects on DRGs after mechanical damage, which could promote cell proliferation, transition of the cell cycle to the G2 phase, and inhibit cell apoptosis. Exogenous administration of XAV939 suppressed the promoting effect of SCs -derived exosomes on DRG cells and the expression of downstream proteins of Wnt/ß-catenin pathway in DRG cells was also suppressed. CONCLUSION: These results suggested that SC-derived exosomes have a repairing effect on DRG cells injury caused by cyclic mechanical stretching (CMS) and the Wnt/ß-catenin pathway is potentially involved in the process.

ABHD15 promotes cell viability, glycolysis, and inhibits apoptosis in cardiomyocytes under hypoxia.

BACKGROUND AND AIMS: Myocardial infarction (MI) has been an important heart disease affecting human health. The aim of this study was to investigate the regulatory effect of abhydrolase domain containing 15 (ABHD15) on hypoxic cardiomyocytes. METHODS AND RESULTS: Hypoxic cardiomyocytes are commonly used as an vitro model for the study of MI. We found that cardiomyocyte viability was decreased under hypoxia, but cell glucose uptake, insulin receptor phosphorylation level and apoptosis were increased. Interestingly, ABHD15 expression was up-regulated in hypoxia-induced cardiomyocytes. Then, we identified the function of ABHD15 in hypoxic cardiomyocytes by using ABHD15 overexpression vector or short interfering RNA (siRNA) against ABHD15. The results showed that overexpression of ABHD15 promoted hypoxic cardiomyocyte viability, glucose uptake and IR phosphorylation (p-IR), and inhibited cell apoptosis. However, knockdown of ABHD15 attenuated hypoxic cardiomyocyte viability, glucose uptake and IR phosphorylation, and promoted apoptosis. Moreover, we found that ABHD15 promoted glucose transporter 4 (GLUT4) expression, translocation and enhance rate-limiting enzyme activation of glycolysis, thereby affecting glucose uptake. Furthermore, our study suggested that ABHD15 may affect the viability and apoptosis of hypoxic cardiomyocytes through IR/Ras/Raf/ERK/MEK and IR/PI3K/AKT/Bcl2/Bad/caspase9 signaling pathways, respectively. When the phosphorylation of IR, Raf or ERK was blocked by inhibitors, the protective effect of overexpressing ABHD15 on the viability of hypoxic cardiomyocytes was eliminated. Furthermore, inhibiting the phosphorylation of IR, AKT or Bcl2 abolished the inhibitory effect of overexpressing ABHD15 on hypoxic cardiomyocyte apoptosis. CONCLUSION: ABHD15 regulated myocardial cell viability, glycolysis, and apoptosis under hypoxia, providing a novel potential therapeutic strategy for MI.

Interleukin-5 deletion promotes sepsis-induced M1 macrophage differentiation, deteriorates cardiac dysfunction, and exacerbates cardiac injury via the NF-κB p65 pathway in mice.

Inflammation plays a crucial role in sepsis-induced cardiac injury. The purpose of this study was to determine whether interleukin-5 (IL-5) affected lipopolysaccharide (LPS)-induced cardiac injury by regulating the inflammatory response. First, the expression level and source of cardiac IL-5 were examined, and the results showed that LPS treatment and cecal ligation decreased cardiac IL-5 expression in macrophages. In addition, LPS was used to establish a mouse sepsis model, and the effects of IL-5 deletion on cardiac injury, M1 macrophage differentiation and myocardial cell apoptosis were analyzed. The results showed that IL-5 deficiency significantly increased cardiac injury marker expression, worsened cardiac dysfunction, promoted M1 macrophage differentiation and exacerbated myocardial cell apoptosis in LPS-induced septic mice. The nuclear factor-kappa B (NF-κB) p65 pathway was inhibited by JSH-23, and the results showed that treatment with JSH-23 inhibited M1 macrophage differentiation and alleviated cardiac injury in LPS-treated IL-5-knockout mice. Furthermore, the effects of IL-5 deficiency on M1 macrophage differentiation and myocardial cell apoptosis were measured in vitro. The IL-5-mediated promotion of M1 macrophage differentiation was also reversed by S31-201, and the pro-apoptotic effect of IL-5 knockout on macrophage-mediated myocardial cell apoptosis was also reversed by JSH-23. In conclusion, we found that IL-5 knockout may exacerbate sepsis-induced cardiac injury by promoting M1 macrophage differentiation in mice. IL-5 may be a potential target for the clinical prevention of sepsis-related cardiac injury.

Effects of electrical stimulation on cell activity, cell cycle, cell apoptosis and ß­catenin pathway in the injured dorsal root ganglion cell.

The present study aimed to investigate the effects of electrical stimulation (ES) on cell activity, cell cycle and apoptosis in injured rat dorsal root ganglion (DRG) cells induced by cyclic mechanical stretching (CMS). The present study also investigated whether the Wnt/ß­catenin pathway is involved in this process. Injury and ES models were established in DRG cells. Then, cell activity was detected using a Cell Counting Kit­8 and 5­ethynyl­2'­deoxyuridine­594 cell proliferation assay kit. Cell cycle distribution was detected using a cell cycle detection kit. Apoptosis was detected using an Annexin V­FITC apoptosis detection kit, and Wnt/ß­catenin pathway­associated proteins were detected using western blotting. The present study demonstrated that CMS decreased DRG cell activity, increased the number of cells in the S phase, promoted cell apoptosis and inhibited the Wnt/ß­catenin pathway. In addition, ES significantly increased the proliferation activity of DRG cells, increased the number of cells in the G2 phase, decreased the apoptotic rate and activated the Wnt/ß­catenin pathway, ultimately reversing the injury caused by CMS. Following inhibition of the Wnt/ß­catenin signaling pathway using XAV939, the effects of ES were weakened. In conclusion, the present study demonstrated that ES may reverse CMS­induced injury in DRG cells, and that the Wnt signaling pathway may be involved in this process.

Electrical stimulation enhances neuronal cell activity mediated by Schwann cell derived exosomes.

Electrical stimulation (ES) therapy has good effects in patients with nervous system injury-related diseases. ES promotes nerve cell regeneration and stimulates Schwann cells to express neurotrophic factors. The incidence of stress urinary incontinence (SUI) among elderly people is increasing. Some studies suggest that damage to the pudendal nerve is closely related to the pathogenesis of SUI. It has also been found that pelvic ES can reduce SUI symptoms in a rat model of SUI caused by pudendal nerve injury. Clinically, pelvic floor electrical stimulation is effective in patients with mild to moderate SUI. These studies indicate that ES may ameliorate damage to the pudendal nerve and thus achieve the goal of SUI treatment, although the mechanism of action of this treatment remains unclear. Therefore, the purpose of the present study was to clarify the relationships among ES, neural cells and Schwann cells at the cellular level. We applied ES to nerve cells at 100 mV/mm or 200 mV/mm for 0, 0.5, 1, or 2 h to investigate changes in nerve cell activity. We then co-cultured the nerve cells with Schwann cells to explore the influence of single-culture and co-culture conditions on the nerve cells. Compared to non-ES, ES of the nerve cells increased their activity. Compared to those in single culture, co-cultured nerve cells exhibited an additional increase in activity. We also found that Schwann cell derived exosomes could promote the activity of nerve cells, with glutamate and calcium ions playing a potential role in this process. These results suggest that the mutual regulation of neural cells and Schwann cells plays an important role in the process by which ES ameliorates neurological function, which may provide a basis for subsequent studies.

Multi-functional stretchable sensors based on a 3D-rGO wrinkled microarchitecture.

The structural design of sensing active layers plays a critical role in the development of electromechanical sensors. In this study, we established an innovative concept for constructing sensors, pre-straining & laser reduction (PS&LR), based on a laser-induced wrinkle effect. This method combines and highlights the advantages of a wrinkled structure in the flexibility of sensors and the advantages of laser in the efficient reduction of GO; thus, it can efficiently introduce tunable, stretchable 3D-rGO expansion bulges in wrinkled GO films. Particularly, the sensors based on this special structure (1.5 cm × 3 cm) demonstrated a multi-functional and distinguished sensing ability in the cases of bending, stretching and touching modes. Moreover, the 3D-rGO architecture endowed the sensors with great sensitivity and design flexibility, i.e., a high sensing factor of 122, relative current value change of 60 times at the bending angle of 60°, decreased relative resistance-strain curve and diverse bending strategies for various detection purposes. Thus, the established design and preparation strategy provides large design flexibility for various promising applications.

Skin-inspired flexible and high-sensitivity pressure sensors based on rGO films with continuous-gradient wrinkles.

Flexible electronic devices have received more and more attention. In particular, for pressure sensors, traditional methods for improving sensing performances are mostly based on the construction of microstructured templates. However, it still remains significantly challenging to conveniently fabricate thin-film sensors which possess flexibility, high sensitivity and location detection ability. Inspired by the microstructure of the human skin surface, herein, a new pressure sensor with a hierarchical structure and gradient reduced graphene oxide (rGO) wrinkles is reported. Benefiting from the skin-like structure, the pressure sensor demonstrates outstanding sensitivity, reaching 178 kPa-1; it can also detect pressure as small as 42 Pa. Furthermore, the concept of designing and constructing a gradient structure has been applied to achieve position detection, which is expected to find practical applications in human motion detection.

WITHDRAWN: Schisandrin B suppresses NLRP3 inflammasome activation to alleviate myocardial ischemia reperfusion injury via maintaining mitochondrial autophagy.

This article has been retracted at the request of the authors. The Editor in Chief has agreed to retract this article and the publisher supports the decision. The authors have indicated that their initial results were not reproducible when conducted by their colleagues. They indicated that the levels of autophagy were significantly different in the MI/R mice model in the respective results. The authors of this article would like to apologize to all affected parties. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Barbaloin pretreatment attenuates myocardial ischemia-reperfusion injury via activation of AMPK.

Myocardial ischemia/reperfusion (MI/R) injury is a major cause of cardiac dysfunction during cardiovascular surgery and heart transplantation and characterized by hyperactive oxidative stress and inflammatory response. Barbaloin (BAR) is the main medicinal composition of the Chinese traditional medicine aloe vera. BAR has strong anti-oxidant, anti-inflammatory and anti-tumor properties. However, the effect of BAR on MI/R-induced myocardial injury is not explored. This study aims to investigate whether BAR provides cardio-protection against MI/R injury and the underlying mechanisms. BAR (20 mg/kg/d) or vehicle was intragastrically administered to Sprague-Dawley rats for 5 days before MI/R operation. BAR pretreatment conferred cardio-protective effects against MI/R injury by improving hemodynamic function and limiting infarction size. Moreover, BAR pretreatment effectively inhibited I/R-induced myocardial oxidative stress and inflammatory response. Furthermore, BAR pretreatment activated adenosine monophosphate-activated protein kinase (AMPK) signaling in MI/R hearts. AMPK inhibitor compound C inhibited BAR-induced AMPK activation, and blunted BAR-mediated anti-oxidative, anti-inflammatory effects and cardio-protection. Taken together our study has identified a novel function of BAR and provided a molecular basis for BAR potential applications in the treatment of MI/R injury and other ischemic disorders.

Long-term performance and microbial ecology of a two-stage PN-ANAMMOX process treating mature landfill leachate.

Long-term performance of a two-stage partial nitritation (PN)-anaerobic ammonium oxidation (ANAMMOX) process treating mature landfill leachate was investigated. Stable partial nitritation performance was achieved in a sequencing batch reactor (SBR) using endpoint pH control, providing an effluent with a ratio of NO2(-)-N/NH4(+)-N at 1.23 ± 0.23. High rate nitrogen removal over 4 kg N/m(3)/d was observed in the ANAMMOX reactor in the first three months. However, during long-term operation, the ANAMMOX reactor can only stably operate under nitrogen load of 1 kg N/m(3)/d, with 85 ± 1% of nitrogen removal. The ammonium oxidizing bacteria (AOB) in the PN-SBR were mainly affiliated to Nitrosomonas sp. IWT514, Nitrosomonas eutropha and Nitrosomonas eutropha, the anaerobic ammonium oxidizing bacteria (AnAOB) in the ANAMMOX reactor were mainly affiliated to Kuenenia stuttgartiensis.

Signal transduction during cold, salt, and drought stresses in plants.

Abiotic stresses, especially cold, salinity and drought, are the primary causes of crop loss worldwide. Plant adaptation to environmental stresses is dependent upon the activation of cascades of molecular networks involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Plants have stress-specific adaptive responses as well as responses which protect the plants from more than one environmental stress. There are multiple stress perception and signaling pathways, some of which are specific, but others may cross-talk at various steps. In this review article, we first expound the general stress signal transduction pathways, and then highlight various aspects of biotic stresses signal transduction networks. On the genetic analysis, many cold induced pathways are activated to protect plants from deleterious effects of cold stress, but till date, most studied pathway is ICE-CBF-COR signaling pathway. The Salt-Overly-Sensitive (SOS) pathway, identified through isolation and study of the sos1, sos2, and sos3 mutants, is essential for maintaining favorable ion ratios in the cytoplasm and for tolerance of salt stress. Both ABA-dependent and -independent signaling pathways appear to be involved in osmotic stress tolerance. ROS play a dual role in the response of plants to abiotic stresses functioning as toxic by-products of stress metabolism, as well as important signal transduction molecules and the ROS signaling networks can control growth, development, and stress response. Finally, we talk about the common regulatory system and cross-talk among biotic stresses, with particular emphasis on the MAPK cascades and the cross-talk between ABA signaling and biotic signaling.

The effect of strontium incorporation into hydroxyapatites on their physical and biological properties.

In this study, the effects of a series of strontium (Sr)-substituted HA ceramics (0, 1, 5, and 10 mol % Sr substitution) were tested on their physical and biological properties. The crystal structure, composition, and solubility were investigated by TEM, XRD, and solid titration solubility isotherms, respectively. In addition, rat MSCs were cultured with culture media containing ions released from the strontium-substituted HA ceramics as they dissolved. MTT test, alkaline phosphatase activity, and osteoblast transcription factor gene (cbfa1) expression were conducted at different time points. Our results suggested that HA with Sr substitution may change its physical properties, especially its solubility, and consequently enhance undifferentiated MSCs into osteoblast lineage. The results from this and the previous study suggested that 5-10 mol % Sr substitution into HA may be a suitable choice for its use in bone regenerative field.

The effect of strontium incorporation in hydroxyapatite on osteoblasts in vitro.

The purpose of this study was to test the effects of a series of strontium-substituted HA (Sr-HA) ceramics (0, 1, 5, and 10 mol% Sr substitution) on osteoblasts, thereby demonstrating whether strontium incorporation with HA would favor osteoblast metabolism. Rat primary osteoblasts were cultured with culture media containing ions released from the Sr-HA ceramics as they dissolved. MTT test, alkaline phosphatase activity, osteoblast transcription factor gene (cbfa1) expression and Alizarin Red staining were conducted at different time-points. There is no significant difference in cell proliferation between groups. However, compared with HA group, Sr-HA groups presented significant enhancement with regard to ALP activity, cbfa1 mRNA expression, and mineralization nodules. Among Sr-HA groups, 5 and 10% groups showed much better performances in ALP activity, cbfa1 mRNA expression, and mineralization nodules than 1% group, however, no significant difference was found between 5 and 10% groups. This study has demonstrated that Sr incorporation in HA ceramic enhanced osteoblastic cell differentiation and mineralization. However, further detailed studies are needed to understand the mechanistic effects of this Sr incorporation on osteoblastic cells and the optimal percentage of calcium should be substituted with strontium in HA.