Dissecting molecular mechanisms underlying ferroptosis in human umbilical cord mesenchymal stem cells: Role of cystathionine γ-lyase/hydrogen sulfide pathway.

BACKGROUND: Ferroptosis can induce low retention and engraftment after mesenchymal stem cell (MSC) delivery, which is considered a major challenge to the effectiveness of MSC-based pulmonary arterial hypertension (PAH) therapy. Interestingly, the cystathionine γ-lyase (CSE)/hydrogen sulfide (H2S) pathway may contribute to mediating ferroptosis. However, the influence of the CSE/H2S pathway on ferroptosis in human umbilical cord MSCs (HUCMSCs) remains unclear. AIM: To clarify whether the effect of HUCMSCs on vascular remodelling in PAH mice is affected by CSE/H2S pathway-mediated ferroptosis, and to investigate the functions of the CSE/H2S pathway in ferroptosis in HUCMSCs and the underlying mechanisms. METHODS: Erastin and ferrostatin-1 (Fer-1) were used to induce and inhibit ferroptosis, respectively. HUCMSCs were transfected with a vector to overexpress or inhibit expression of CSE. A PAH mouse model was established using 4-wk-old male BALB/c nude mice under hypoxic conditions, and pulmonary pressure and vascular remodelling were measured. The survival of HUCMSCs after delivery was observed by in vivo bioluminescence imaging. Cell viability, iron accumulation, reactive oxygen species production, cystine uptake, and lipid peroxidation in HUCMSCs were tested. Ferroptosis-related proteins and S-sulfhydrated Kelch-like ECH-associating protein 1 (Keap1) were detected by western blot analysis. RESULTS: In vivo, CSE overexpression improved cell survival after erastin-treated HUCMSC delivery in mice with hypoxia-induced PAH. In vitro, CSE overexpression improved H2S production and ferroptosis-related indexes, such as cell viability, iron level, reactive oxygen species production, cystine uptake, lipid peroxidation, mitochondrial membrane density, and ferroptosis-related protein expression, in erastin-treated HUCMSCs. In contrast, in vivo, CSE inhibition decreased cell survival after Fer-1-treated HUCMSC delivery and aggravated vascular remodelling in PAH mice. In vitro, CSE inhibition decreased H2S levels and restored ferroptosis in Fer-1-treated HUCMSCs. Interestingly, upregulation of the CSE/H2S pathway induced Keap1 S-sulfhydration, which contributed to the inhibition of ferroptosis. CONCLUSION: Regulation of the CSE/H2S pathway in HUCMSCs contributes to the inhibition of ferroptosis and improves the suppressive effect on vascular remodelling in mice with hypoxia-induced PAH. Moreover, the protective effect of the CSE/H2S pathway against ferroptosis in HUCMSCs is mediated via S-sulfhydrated Keap1/nuclear factor erythroid 2-related factor 2 signalling. The present study may provide a novel therapeutic avenue for improving the protective capacity of transplanted MSCs in PAH.

Machine learning assisted interpretation of 2D solid-state nuclear magnetic resonance spectra.

A machine learning methodology using deep neural network (DNN) for interpreting multidimensional solid-state nuclear magnetic resonance (SSNMR) of various synthetic and natural polymers is presented. The separated local field (SLF) SSNMR which correlates local well-defined heteronuclear dipolar with the tensor orientation of the chemical shift anisotropy (CSA) of spin in the solid state can provide valuable structure and molecular dynamics information of synthetic and biopolymers. Compared with the traditional linear least-square fitting, the proposed DNN-based methodology can efficiently and accurately determine the tensor orientation of CSA of both 13C and 15N in all four samples. The method achieves prediction precisions of the Euler angles with < ±5° and is characterized by low training costs and high efficiency (<1 s). The feasibility and robustness of the DNN-based analysis methodology are confirmed by comparison to reported-literature values. This strategy is expected to aid in the interpretation of complex multidimensional NMR spectra of complicated polymer system.

Mammalian Ste20-like kinase 1 inhibition as a cellular mediator of anoikis in mouse bone marrow mesenchymal stem cells.

BACKGROUND: The low survival rate of mesenchymal stem cells (MSCs) caused by anoikis, a form of apoptosis, limits the therapeutic efficacy of MSCs. As a proapoptotic molecule, mammalian Ste20-like kinase 1 (Mst1) can increase the production of reactive oxygen species (ROS), thereby promoting anoikis. Recently, we found that Mst1 inhibition could protect mouse bone marrow MSCs (mBMSCs) from H2O2-induced cell apoptosis by inducing autophagy and reducing ROS production. However, the influence of Mst1 inhibition on anoikis in mBMSCs remains unclear. AIM: To investigate the mechanisms by which Mst1 inhibition acts on anoikis in isolated mBMSCs. METHODS: Poly-2-hydroxyethyl methacrylate-induced anoikis was used following the silencing of Mst1 expression by short hairpin RNA (shRNA) adenovirus transfection. Integrin (ITGs) were tested by flow cytometry. Autophagy and ITGα5ß1 were inhibited using 3-methyladenine and small interfering RNA, respectively. The alterations in anoikis were measured by Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling and anoikis assays. The levels of the anoikis-related proteins ITGα5, ITGß1, and phospho-focal adhesion kinase and the activation of caspase 3 and the autophagy-related proteins microtubules associated protein 1 light chain 3 II/I, Beclin1 and p62 were detected by Western blotting. RESULTS: In isolated mBMSCs, Mst1 expression was upregulated, and Mst1 inhibition significantly reduced cell apoptosis, induced autophagy and decreased ROS levels. Mechanistically, we found that Mst1 inhibition could upregulate ITGα5 and ITGß1 expression but not ITGα4, ITGαv, or ITGß3 expression. Moreover, autophagy induced by upregulated ITGα5ß1 expression following Mst1 inhibition played an essential role in the protective efficacy of Mst1 inhibition in averting anoikis. CONCLUSION: Mst1 inhibition ameliorated autophagy formation, increased ITGα5ß1 expression, and decreased the excessive production of ROS, thereby reducing cell apoptosis in isolated mBMSCs. Based on these results, Mst1 inhibition may provide a promising strategy to overcome anoikis of implanted MSCs.

A versatile biaxial stretching device for in situ synchrotron radiation small- and wide-angle x-ray scattering measurements of polymer films.

A biaxial stretching device is designed and developed for the real-time structural measurements of polymer films. This device adopts a vertical layout to perform real-time x-ray scattering measurements. It has a maximum stretching ratio of 8 × 8 in two perpendicular directions. Its maximum experimental temperature and stretching rate are 250 °C and 100 mm/s, respectively. The control accuracies of the experimental temperature and stretching rate are ±1 °C and 0.01 mm, respectively. All the parameters related to film biaxial processing, such as stretching speed, stretching ratio, and temperature, can be independently set. The device feasibility is demonstrated via a real-time experiment in a synchrotron radiation beamline. Wide-angle x-ray diffraction, small-angle x-ray scattering, and stress-strain data can be simultaneously obtained during various stretching modes. The proposed device fills the gap between the synchrotron radiation x-ray scattering technique and the biaxial stretching processing of polymer films. This device will play an important role in improving the understanding of the physics behind biaxial polymer processing.

Metallic Glass-Fiber Fabrics: A New Type of Flexible, Super-Lightweight, and 3D Current Collector for Lithium Batteries.

Current collectors are indispensable parts that provide electron transport and mechanical support of electrode materials in a battery. Nowadays, thin metal foils made of Cu and Al are used as current collectors of lithium batteries, but they do not contribute to the storage capacity. Therefore, decreasing the weight of current collectors can directly enhance the energy density of a battery. However, limited by the requirements of mechanical strength, it is difficult to reduce the weight of metal foils any further. Herein, a new type of current collectors made of 3D metallic glass-fiber fabrics (MGFs), which shows advantages of super-lightweight (2.9-3.2 mg cm⁻2 ), outstanding electrochemical stability for cathodes and anodes of lithium-ion and lithium-metal batteries (LMBs), fire resistance, high strength, and flexibility suitable for roll-to-roll electrode fabrication is reported. The gravimetric energy densities of lithium batteries exhibit improvements of 9-18% by only replacing the metal foils with the MGFs. In addition, MGFs are suitable for the fabrication of flexible batteries. A high-energy-density flexible lithium battery with an outstanding figure of merit of flexible battery (fbFOM ) and flexing stability is demonstrated.

Shafting Misalignment Malfunction Quantitative Diagnosis Based on Speed Signal SVD-HT and CSF-PPSO-ESN Method.

Aiming at the quantitative diagnosis of shafting misalignment malfunction, a novel method based on speed signal with singular value decomposition and Hilbert transform (SVD-HT) and cubic spline fitting-Pareto particle swarm optimization-echo state network (CSF-PPSO-ESN) method is proposed. The malfunction diagnosis mechanism based on the speed signal is obtained by constructing the shaft misalignment malfunction model. Then, the SVD-HT and CSF-PPSO-ESN methods are applied to obtain the relationship between the shaft misalignment malfunction and the amplitude of the time and the rotation frequency (f r ) component of the speed signal. The parameters of the CSF-PPSO-ESN method are settled according to the shaft misalignment malfunction and the f r component of the speed signal. The accuracy of the proposed method is verified by using the f r component of the speed signal and the trained CSF-PPSO-ESN to obtain the value of the shaft misalignment malfunction. The repeating experimental results show that the diagnosing error of the shaft misalignment malfunction can reach less than ±10 µm. The method presented in this paper provides a novel way to diagnose shaft misalignment malfunction quantitatively.

Regulation of orientation birefringence for cellulose acetate film: The role of crystallization and orientation.

Cellulose acetate (CA) based films are widely used in liquid crystal displays due to their outstanding transparency, and a certain orientation birefringence of CA films is required when they are used as retardation films. The regulation of orientation birefringence is usually from the perspective of stretch-induced orientation, while the effects of crystallization behaviors of CA films remain obscure. In this study, the roles of crystallization and orientation on the orientation birefringence of CA films were elucidated. For cellulose diacetate films, the orientation birefringence is dominated by the orientation degree. In comparison, apart from the orientation degree, crystallinity is another key variable to regulate the orientation birefringence of cellulose triacetate and plasticized cellulose triacetate films, originating from the birefringence heterogeneity of the crystalline and amorphous phases. These results provide valuable guidelines for the production of CA-based optical films with excellent optical performance.

A Healable and Mechanically Enhanced Composite with Segregated Conductive Network Structure for High-Efficient Electromagnetic Interference Shielding.

HIGHLIGHTS: The cationic waterborne polyurethanes microspheres with Diels-Alder bonds were synthesized for the first time. The electrostatic attraction not only endows the composite with segregated structure to gain high electromagnetic-interference shielding effectiveness, but also greatly enhances mechanical properties. Efficient healing property was realized under heating environment. It is still challenging for conductive polymer composite-based electromagnetic interference (EMI) shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness (EMI SE), especially undergoing external mechanical stimuli, such as scratches or large deformations. Herein, an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube (CNT)/graphene oxide (GO)/polyurethane (PU) composite with excellent and reliable EMI SE, even bearing complex mechanical condition. The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite, establishing a high EMI SE of 52.7 dB at only 10 wt% CNT/GO loading. The Diels-Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%. Additionally, the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite, resulting in high tensile strength of 43.1 MPa and elongation at break of 626%. The healing efficiency of elongation at break achieves 95% when the composite endured three cutting/healing cycles. This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments.

Dissecting molecular mechanisms underlying H2O2-induced apoptosis of mouse bone marrow mesenchymal stem cell: role of Mst1 inhibition.

BACKGROUND: Bone marrow mesenchymal stem cell (BM-MSC) has been shown to treat pulmonary arterial hypertension (PAH). However, excessive reactive oxygen species (ROS) increases the apoptosis of BM-MSCs, leading to poor survival and engraft efficiency. Thus, improving the ability of BM-MSCs to scavenge ROS may considerably enhance the effectiveness of transplantation therapy. Mammalian Ste20-like kinase 1 (Mst1) is a pro-apoptotic molecule which increases ROS production. The aim of this study is to uncover the underlying mechanisms the effect of Mst1 inhibition on the tolerance of BM-MSCs under H2O2 condition. METHODS: Mst1 expression in BM-MSCs was inhibited via transfection with adenoviruses expressing a short hairpin (sh) RNA directed against Mst1 (Ad-sh-Mst1) and exposure to H2O2. Cell viability was detected by Cell Counting Kit 8 (CCK-8) assay, and cell apoptosis was analyzed by Annexin V-FITC/PI, Caspase 3 Activity Assay kits, and pro caspase 3 expression. ROS level was evaluated by the ROS probe DCFH-DA, mitochondrial membrane potential (ΔΨm) assay, SOD1/2, CAT, and GPx expression. Autophagy was assessed using transmission electron microscopy, stubRFP-sensGFP-LC3 lentivirus, and autophagy-related protein expression. The autophagy/Keap1/Nrf2 signal in H2O2-treated BM-MSC/sh-Mst1 was also measured. RESULTS: Mst1 inhibition reduced ROS production; increased antioxidant enzyme SOD1/2, CAT, and GPx expression; maintained ΔΨm; and alleviated cell apoptosis in H2O2-treated BM-MSCs. In addition, this phenomenon was closely correlated with the autophagy/Keap1/Nrf2 signal pathway. Moreover, the antioxidant pathway Keap1/Nrf2 was also blocked when autophagy was inhibited by the autophagy inhibitor 3-MA. However, Keap1 or Nrf2 knockout via siRNA had no effect on autophagy activation or suppression. CONCLUSION: Mst1 inhibition mediated the cytoprotective action of mBM-MSCs against H2O2-induced oxidative stress injury. The underlying mechanisms involve autophagy activation and the Keap1/Nrf2 signal pathway.

Expression of pulmonary arterial elastin in rats with hypoxic pulmonary hypertension using H2S.

Object: This study analyses the changes of pulmonary arterial elastin expression inhibited by hydrogen sulfide (H2S) in rats with hypoxic pulmonary hypertension.Method: The research used 30 healthy rats and randomly divided them into control group, hypoxia group, and hypoxia + sodium hydrosulfide group. Each group contains 10 samples. The right catheterization was selected to measure the mean pulmonary artery pressure (mPAP). The RV/LV + S ratio was calculated through separating the right ventricle and the left ventricle plus the interventricular septum. Optical microscopy was used to observe the changes of pulmonary vascular structure. The research used immunohistochemistry to express the levels of elastin and transforming growth factor beta (TGF-ß).Results: The ratios of Mpap and RV/LV + S in the hypoxic group exceed the control group. The hypoxia + sodium hydrosulfide group (hypoxia + NaHS) is lower than the hypoxic group. In the hypoxic group, the elastic expressions of medium and small pulmonary artery smooth muscle cells exceed the control group. The expression of elastin in hypoxic + NaHS medium and small pulmonary artery smooth muscle cells is lower than that of the control group.The protein expression levels of α-SM-actin in muscle arterial smooth muscle of pulmonary arterioles in hypoxic group, control group and hypoxic + NaHS group were 49.84% + 6.27%, 56.84% + 6.38%, 23.82% + 3.84%, 27.51% + 3.24%, 29.00% + 4.05%, 34.72% + 3.38%.Conclusion: Hydrogen sulfide in rats with hypoxic pulmonary hypertension can inhibit the expression of elastin in its extracellular matrix, which also has remarkable regulation function in forming HPH and remodeling hypoxic pulmonary vascular structure.

Microstructural Origin of the Double Yield Points of the Metallocene Linear Low-Density Polyethylene (mLLDPE) Precursor Film under Uniaxial Tensile Deformation.

The microstructural origin of the double yield points of metallocene linear low-density polyethylene (mLLDPE) precursor films has been studied with the assistance of the synchrotron radiation small- and wide-angle X-ray scattering (SAXS/WAXS). It has been shown that the microstructural origin of the double yield points is highly related to the initial orientation of the original precursor film. For less oriented mLLDPE precursor films, the rearrangement of lamellae and the appearance of the monoclinic phase are the microstructural origins of the first yield point. In comparison, for the highly-oriented mLLDPE precursor film, only the orthorhombic-monoclinic phase transition appears at the first yield point. The melting-recrystallization and the formation of the fibrillary structure happen beyond the second yield point for all studied mLLDPE precursor films. Finally, the detailed microstructural evolution roadmaps of mLLDPE precursor films under uniaxial tensile deformation have been established, which might serve as a guide for processing high-performance polymer films by post-stretching.

rBMSC/Cav-1F92A Mediates Oxidative Stress in PAH Rat by Regulating SelW/14-3-3η and CA1/Kininogen Signal Transduction.

BACKGROUND/OBJECTIVES: Carbonic anhydrase 1 (CA1)/kininogen and selenoprotein W (SelW)/14-3-3η signal transduction orchestrate oxidative stress, which can also be regulated by nitric oxide (NO). The mutated caveolin-1 (Cav-1F92A) gene may enhance NO production. This study explored the effect of Cav-1F92A-modified rat bone marrow mesenchymal stem cells (rBMSC/Cav-1F92A) on oxidative stress regulation through CA1/kininogen and SelW/14-3-3η signal transduction in a rat model of monocrotaline- (MCT-) induced pulmonary arterial hypertension (PAH). METHOD: PAH was induced in rats through the subcutaneous injection of MCT. Next, rBMSC/Vector (negative control), rBMSC/Cav-1, rBMSC/Cav-1F92A, or rBMSC/Cav-1F92A+L-NAME were administered to the rats. Changes in pulmonary hemodynamic and vascular morphometry and oxidative stress levels were evaluated. CA1/kininogen and SelW/14-3-3η signal transduction, endothelial nitric oxide synthase (eNOS) dimerization, and eNOS/NO/sGC/cGMP pathway changes were determined through real-time polymerase chain reaction, Western blot, or immunohistochemical analyses. RESULTS: In MCT-induced PAH rats, rBMSC/Cav-1F92A treatment reduced right ventricular systolic pressure, vascular stenosis, and oxidative stress; downregulated CA1/kininogen signal transduction; upregulated SelW/14-3-3η signal transduction; and reactivated the NO pathway. CONCLUSIONS: In a rat model of MCT-induced PAH, rBMSC/Cav-1F92A reduced oxidative stress by regulating CA1/kininogen and SelW/14-3-3η signal transduction.

Generating the conformational properties of a polymer by the restricted Boltzmann machine.

In polymer theory, computer-generated polymer configurations, by either Monte Carlo simulations or molecular dynamics simulations, help us to establish the fundamental understanding of the conformational properties of polymers. Here, we introduce a different method, exploiting the properties of a machine-learning algorithm, the restricted Boltzmann machine network, to generate independent polymer configurations for self-avoiding walks (SAWs), for studying the conformational properties of polymers. We show that with adequate training data and network size, this method can capture the underlying polymer physics simply from learning the statistics in the training data without explicit information on the physical model itself. We critically examine how the trained Boltzmann machine can generate independent configurations that are not in the original training data set of SAWs.

Yap overexpression attenuates septic cardiomyopathy by inhibiting DRP1-related mitochondrial fission and activating the ERK signaling pathway.

Context: Yes-associated protein (Yap) has been linked to several cardiovascular disorders, but the role of this protein in septic cardiomyocytes is not fully understood. Objective: The aim of our study was to explore the influence of Yap in septic cardiomyopathy in vivo and in vitro. Materials and methods: In the current study, Yap transgenic mice and Yap adenovirus-mediated gain-of-function assays were used in an LPS-established septic cardiomyopathy model. Mitochondrial function and mitochondrial fission were determined through western blotting, immunofluorescence analysis and ELISA. Results: Our results demonstrated that Yap expression was downregulated by LPS, whereas Yap overexpression sustained cardiac function and attenuated cardiomyocyte death. The functional exploration revealed that LPS treatment induced cardiomyocyte mitochondrial stress, as manifested by mitochondrial superoxide overproduction, cardiomyocyte ATP deprivation, and caspase-9 apoptosis activation. Furthermore, we demonstrated that LPS-mediated mitochondrial damage was controlled by mitochondrial fission. However, Yap overexpression reduced mitochondrial fission and therefore improved mitochondrial function. A molecular investigation revealed that Yap overexpression inhibited mitochondrial fission by reversing ERK activity, and the inhibition of the ERK pathway promoted DRP1 upregulation and thereby mediated mitochondrial fission activation in the presence of Yap overexpression. Conclusions: Overall, our results suggest that the cause of septic cardiomyopathy appears to be connected with Yap downregulation. The overexpression of Yap can attenuate myocardial inflammation injury through the reduction of DRP1-related mitochondrial fission in an ERK pathway activation-dependent manner.

Mst1 promotes cardiac ischemia-reperfusion injury by inhibiting the ERK-CREB pathway and repressing FUNDC1-mediated mitophagy.

Cardiac ischemia-reperfusion (I/R) injury results mainly from mitochondrial dysfunction and cardiomyocyte death. Mitophagy sustains mitochondrial function and exerts a pro-survival effect on the reperfused heart tissue. Mammalian STE20-like kinase 1 (Mst1) regulates chronic cardiac metabolic damage and autophagic activity, but its role in acute cardiac I/R injury, especially its effect on mitophagy, is unknown. The aim of this study is to explore whether Mst1 is involved in reperfusion-mediated cardiomyocyte death via modulation of FUN14 domain containing 1 (FUNDC1)-related mitophagy. Our data indicated that Mst1 was markedly increased in reperfused hearts. However, genetic ablation of Mst1 in Mst1-knockout (Mst1-KO) mice significantly reduced the expansion of the cardiac infarction area, maintained myocardial function and abolished I/R-mediated cardiomyocyte death. At the molecular level, upregulation of Mst1 promoted ROS production, reduced mitochondrial membrane potential, facilitated the leakage of mitochondrial pro-apoptotic factors into the nucleus, and activated the caspase-9-related apoptotic pathway in reperfused cardiomyocytes. Mechanistically, Mst1 activation repressed FUNDC1 expression and consequently inhibited mitophagy. However, deletion of Mst1 was able to reverse FUNDC1 expression and thus re-activate protective mitophagy, effectively sustaining mitochondrial homeostasis and blocking mitochondrial apoptosis in reperfused cardiomyocytes. Finally, we demonstrated that Mst1 regulated FUNDC1 expression via the MAPK/ERK-CREB pathway. Inhibition of the MAPK/ERK-CREB pathway prevented FUNDC1 activation caused by Mst1 deletion. Altogether, our data confirm that Mst1 deficiency sends a pro-survival signal for the reperfused heart by reversing FUNDC1-related mitophagy and thus reducing cardiomyocyte mitochondrial apoptosis, which identifies Mst1 as a novel regulator for cardiac reperfusion injury via modulation of mitochondrial homeostasis.

Dissecting Molecular Mechanisms Underlying Pulmonary Vascular Smooth Muscle Cell Dedifferentiation in Pulmonary Hypertension: Role of Mutated Caveolin-1 (Cav1F92A)-Bone Marrow Mesenchymal Stem Cells.

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterised by remodelling in vascular smooth muscles, and switching from contractile (differentiated) to synthetic (dedifferentiated) phenotype. This study aimed to investigate the effect of a mutated caveolin-1 (Cav1F92A) gene from bone marrow mesenchymal stem cells (rBMSCs) on phenotypic switching in the smooth muscle cells during PAH. METHODS: Human pulmonary smooth muscle cells (HPASMCs) were treated with monocrotaline (MCT,1µM), and co-cultured with Cav1F92A gene modified rBMSCs (rBMSCs/Cav1F92A). The nitric oxide (NO) production, cell adhesion, cell viability and inflammatory cytokines expression in rBMSCs was measured to evaluate the survival rate of rBMSCs and the changes of inflammatory cytokines. The concentration of NO/cGMP (nitric oxide/Guanosine-3',5'-cyclic monophosphate), the tumour necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-ß1) mRNA, the expression of contractile smooth muscle cells (SMCs) phenotype markers (thrombospondin-1 and Matrix Gla protein, MGP), the synthetic SMCs phenotype markers (H-caldesmon and smooth muscle gene SM22 alpha, SM22α), cell migration and the morphological changes in rBMSCs/Cav1F92A co-cultured HPASMCs were investigated. RESULTS: Cav1F92A increased NO concentration, cell adhesion, cell viability, anti-inflammatory cytokines interleukin-4 (IL-4), and interleukin-10 (IL-10), but decreased the inflammatory cytokines interleukin-1α (IL-1α), interferon-γ (INF-γ) and TNF-α expression in rBMSCs. rBMSCs/Cav1F92A activated the NO/cGMP, down-regulated TNF-α, TGF-ß1, thrombospondin-1 and MGP expression, up-regulated SM22α and H-caldesmon expression, restored cell morphology, and inhibited cell migration in MCT treated HPASMCs. CONCLUSIONS: rBMSCs/Cav1F92A inhibits switching from contractile to synthetic phenotype in HPASMCs. It also inhibits migration and promotes morphological restoration of these cells. rBMSCs/Cav1F92A may be used as a therapeutic modality for PAH.

The effects of hyperoxia liquid regulate cardiopulmonary bypass­induced myocardial damage through the Nrf2­ARE signaling pathway.

The aim of the present study was to investigate the protective role of hyperoxia liquid in regulating cardiopulmonary bypass (CPB)­induced myocardial damage and its possible underlying mechanism. In the CPB­induced rat model, hyperoxia liquid enhanced left ventricular ejection fraction (LVEF), reduced the left ventricular internal dimension systole (LVIDs) level, inhibited malondialdehyde levels, increased superoxide dismutase, glutathione (GSH) and GSH peroxidase levels, suppressed heart cell apoptosis, and induced the nuclear factor erythroid 2­related factor 2 (Nrf2) and heme oxygenase­1 (HO­1) signaling pathway. Then, ML385, a Nrf2 inhibitor, was used to attenuate the effect of hyperoxia liquid on LVEF and LVIDs levels, oxidative stress and heart cell apoptosis in the CPB­induced rat model. Collectively, the results of the present study demonstrated that the protective role of hyperoxia liquid may regulate oxidative stress in a CPB­induced rat model through the Nrf2­antioxidant response element signaling pathway.

Zinc ion rapidly induces toxic, off-pathway amyloid-ß oligomers distinct from amyloid-ß derived diffusible ligands in Alzheimer's disease.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in the elderly. Zinc (Zn) ion interacts with the pathogenic hallmark, amyloid-ß (Aß), and is enriched in senile plaques in brain of AD patients. To understand Zn-chelated Aß (ZnAß) species, here we systematically characterized ZnAß aggregates by incubating equimolar Aß with Zn. We found ZnAß40 and ZnAß42 both form spherical oligomers with a diameter of ~12-14 nm composed of reduced ß-sheet content. Oligomer assembly examined by analytical ultracentrifugation, hydrophobic exposure by BisANS spectra, and immunoreactivity of ZnAß and Aß derived diffusible ligands (ADDLs) are distinct. The site-specific 13C labeled solid-state NMR spectra showed that ZnAß40 adopts ß-sheet structure as in Aß40 fibrils. Interestingly, removal of Zn by EDTA rapidly shifted the equilibrium back to fibrillization pathway with a faster kinetics. Moreover, ZnAß oligomers have stronger toxicity than ADDLs by cell viability and cytotoxicity assays. The ex vivo study showed that ZnAß oligomers potently inhibited hippocampal LTP in the wild-type C57BL/6JNarl mice. Finally, we demonstrated that ZnAß oligomers stimulate hippocampal microglia activation in an acute Aß-injected model. Overall, our study demonstrates that ZnAß rapidly form toxic and distinct off-pathway oligomers. The finding provides a potential target for AD therapeutic development.

Integrin alpha5beta1 suppresses rBMSCs anoikis and promotes nitric oxide production.

BACKGROUND: Cell based therapy has been heralded as a novel, promising therapeutic strategy for cardiovascular diseases including pulmonary arterial hypertension (PAH). However, the low survival rate after transplantation due to cell death via anoikis is a major obstacle in stem cell therapy. Cells adhesion via Integrin alpha5beta1 (ITGA5B1) has a tendency to exert higher maximum forces. The present study aimed to evaluate the potential protective effect of ITGA5B1 on rat bone marrow mesenchymal stem cells (rBMSCs) from anoikis. METHODS: Mononuclear cells were isolated by density gradient centrifugation with Ficoll, and rBMSCs cell surface markers were evaluated by flow cytometry. Osteogenic and adipocyte differentiation was determined by Alizarin Red S and Oil Red O staining respectively. The expression of Integrin A5 (ITGA5), Integrin B1 (ITGB1), eNOS and actived-caspase-3 mRNA or protein was confirmed by qPCR and western-blot. Cell adhesion, cell viability, anoikis and the migration of rBMSCs were also evaluated. Nitric oxide (NO) production was detected by the greiss assay. RESULTS: Co-infected with Integrin A5 and B1 lentivirus to rBMSCs increased ITGA5 and ITGB1 mRNA and protein expression. ITGA5B1 enhanced the cell adhesion, cell viability, cell migration and NO production but reduced the cell anoikis in rBMSCs/ITGA5B1 groups. CONCLUSION: Transduction of rat rBMSCs with ITGA5B1 lentivirus could prevent cell anoikis and increase NO production.

Spatial heterogeneity can facilitate the target search of self-propelled particles.

A numerical investigation of the target search dynamics of self-propelled particles (SPPs) in heterogeneous environments is presented in this work. We show that the spatial heterogeneity has a dramatic effect on the target search dynamics of SPPs. The relative magnitude of the self-propulsion length lp and the radius of the circular domain Rc determines how the mean search time of SPPs τ depends on the area fraction of fixed obstacles ϕob. For lp < Rc, the target search process is diffusion-dominated so that a monotonic increase in τ with increasing ϕob is observed. For lp > Rc, τ is shown to be a non-monotonic convex function as a function of ϕob due to the interplay of the distribution-dominated and diffusion-dominated dynamic regimes. Furthermore, at fixed ϕob, τ shows a minimum upon increasing the self-propulsion velocity v0 of a SPP of a slow rotational diffusion when it searches for a target at low ϕob, while it decreases monotonically at high ϕob. The present work highlights that the introduction of spatial heterogeneity causes rich dynamic behaviors of a SPP searching for a target, and deepens our understanding of the transport of active matter in heterogeneous media.