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Despite a lack of mutations, accumulating evidence supports an important role for the Wnt/β-catenin pathway in ovarian tumorigenesis. However, the molecular mechanism that contributes to the aberrant activation of the Wnt signaling cascade in ovarian cancer has not been fully elucidated. Here, we found that protein tyrosine phosphatase receptor type R (PTPRR) suppressed the activation of the Wnt/β-catenin pathway in ovarian cancer. We performed an shRNA-based biochemical screen, which identified PTPRR as being responsible for tyrosine dephosphorylation of β-catenin on Tyr-142, a key site controlling the transcriptional activity of β-catenin. Of note, PTPRR was down-regulated in ovarian cancers, and ectopic PTPRR re-expression delayed ovarian cancer cell growth both in vitro and in vivo. Using a proximity-based tagging system and RNA-Seq analysis, we identified a signaling nexus that includes PTPRR, -catenin, β-catenin, E-cadherin, and AT-rich interaction domain 3C (ARID3C) in ovarian cancer. Immunohistochemistry staining of human samples further suggested that PTPRR expression is inversely correlated with disease prognosis. Collectively, our findings indicate that PTPRR functions as a tumor suppressor in ovarian cancer by dephosphorylating and inactivating β-catenin. These results suggest that PTPRR expression might have utility as a prognostic marker for predicting overall survival. [ABSTRACT FROM AUTHOR]

Reliable joining of ZrO2 ceramic to TiAl alloy is crucial for the success of the engine industrial application. However, there have been few systematic investigations on joining of ZrO2 ceramic and TiAl alloy. In this study, reliable brazing of ZrO2 ceramic and TiAl alloy was achieved using inactive AgCu filler metal. The interfacial microstructure of the joints was characterized by SEM, XRD and TEM. Effects of holding time on the microstructure and mechanical properties of the joints were investigated in details. The results revealed that Cu3Ti3O + TiO layers were formed adjacent to ZrO2 ceramic while AlCu2Ti layer was formed at TiAl substrate. The thickness of Cu3Ti3O + TiO layers increased and the granular AlCu2Ti coarsened gradually with the prolongation of holding time. The hardness and Young's modulus of reaction phases were characterized by nano-indentation to reveal the plastic deformability. The highest shear strength of 48.4 MPa was achieved when brazed at 880 °C for 10 min. [ABSTRACT FROM AUTHOR]

Background aims. The purpose of the study was to investigate the feasibility of in vitro and in vivo bioluminescence imaging (BLI), fluorescence imaging (FI) and magnetic resonance imaging (MRI) to trace transplanted bone mesenchymal stromal cells (BMSCs) labeled with the firefly luciferase (Flue) reporter gene, Cyl dyes and ultra-small super-paramagnetic iron oxide (USPIO) particles. Methods. Fluc-transfected BMSCs were further labeled with Cyl dyes and USPIO particles, respectively. Acute myocardial infarction models of different weighted Sprague-Dawley rats and Balb/c mice were established, and BLI and FI were performed in vivo and ex vivo to determine the optimal method of optical imaging. Finally, BLI and MRI were selected to trace transplanted BMSCs in a murine model in vivo. Results. BLI was found to be the optimal optical imaging method in vivo, compared with FI, and mice were found to be the optimal animal model, compared with rats. A significant BLI signal intensity was detected in the heart region in the BMSC-treated mice group (40,552 ± 6073 counts, n = 26) and gradually decreased below the detection threshold. Two distinct hypo-intense regions were observed in the anterior wall of the heart, where stem cells were injected on MR images obtained with the gradient recalled echo cine sequence in the BMSC-treated mice group. Conclusions. Transplanted BMSCs labeled with Flue reporter gene and USPIO particles can be traced with the use of BLI and MRI in a mouse model of acute myocardial infarction. [ABSTRACT FROM AUTHOR]

This documentation presents the parametric identification modeling of ship maneuvering motion with integral sample structure for identification (ISSI) and Euler sample structure for identification (ESSI) based on least square support vector machines (LS-SVM), where ISSI is used for the construction of in–out sample pairs. By using Mariner Class Vessel , the sample dataset are obtained from 15°/15° zigzag maneuvering simulation based on Abkowitz model. By analyzing the simulation data including rudder angle, surge velocity, sway velocity, yaw rate and so forth, the hydrodynamic derivatives in Abkowitz model are all identified. The validation of the proposed identification algorithm is verified by the high precisions of the identified hydrodynamic derivatives and maneuvering prediction results. The comparison is also conducted between the proposed ISSI and the conventional Euler sample structure for identification (ESSI), and the experimental results shows that ISSI is much more appropriate for parametric identification modeling of ship maneuvering motion. [ABSTRACT FROM AUTHOR]

The JmjC domain-containing H3K4 histone demethylase jumonji AT-rich interactive domain 1B (JARID1B) (also known as KDM5B and PLU1) is overexpressed in breast cancer and is a potential target for breast cancer treatment. To investigate the in vivo function of JARID1B, we developed Jarid1b-/- mice and characterized their phenotypes in detail. Unlike previously reported Jarid1b-/- strains, the majority of these Jarid1b-/- mice were viable beyond embryonic and neonatal stages. This allowed us to further examine phenotypes associated with the loss of JARID1B in pubertal development and pregnancy. These Jarid1b-/- mice exhibited decreased body weight, premature mortality, decreased female fertility, and delayed mammary gland development. Related to these phenotypes, JARID1B loss decreased serum estrogen level and reduced mammary epithelial cell proliferation in early puberty. In mammary epithelial cells, JARID1B loss diminished the expression of key regulators for mammary morphogenesis and luminal lineage specification, including FOXA1 and estrogen receptor α. Mechanistically, JARID1B was required for GATA3 recruitment to the Foxa1 promoter to activate Foxa1 expression. These results indicate that JARID1B positively regulates mammary ductal development through both extrinsic and cell-autonomous mechanisms. [ABSTRACT FROM AUTHOR]

JARID1B (also known as KDM5B or PLU1) is a member of the JARID1 family of histone lysine demethylases responsible for the demethylation of trimethylated lysine 27 in histone H3 (H3K4me3), a mark for actively transcribed genes. JARID1B is overexpressed in several cancers, including breast cancer, prostate cancer, and lung cancer. In addition, JARID1B is required for mammary tumor formation in syngeneic or xenograft mouse models. JARID1B-expressing melanoma cells are associated with increased self-renewal character. Therefore, JARID1B represents an attractive target for cancer therapy. Here we characterized JARID1B using a homogeneous luminescence-based demethylase assay. We then conducted a high throughput screen of over 15,000 small molecules to identify inhibitors of JARID1B. From this screen, we identified several known JmjC histone demethylase inhibitors, including 2,4-pyridinedicarboxylic acid and catechols. More importantly, we identified several novel inhibitors, including 2-4(4-methylphenyl)-1,2-benzisothiazol-3(2H)-one (PBIT), which inhibits JARID1B with an IC50 of about 3 μM in vitro. Consistent with this, PBIT treatment inhibited removal of H3K4me3 by JARID1B in cells. Furthermore, this compound inhibited proliferation of cells expressing higher levels of JARID1B. These results suggest that this novel small molecule inhibitor is a lead compound that can be further optimized for cancer therapy. [ABSTRACT FROM AUTHOR]

Abstract: Through analysis and evaluation of water consumption on-site survey of near 200 large public buildings, the necessity of the application and discussion of internet of things on wireless remote transmission of water consumption data and subentry measure are discussed. This paper advances the program of wireless remote monitoring system based on internet of things, which not only provides the ways to obtain data foundation for government policy decision by internet of things on wireless remote transmission, but finds the method and potential for energy-saving. At the same time, it can implement the development of internet of things and come up to the aim of energy-saving based on internet of things. [Copyright &y& Elsevier]

Abstract: In China nowadays, some enterprises begin to develop the sustainable supply chain (S-SC) because of the strengthening of environment regulations. How to deal with certain multi-criteria decision-making problems effectively and efficiently is the key for the development of S-SC. In this paper, the main factors and their relationship during the operation of S-SC were analyzed, and combined with the analytic network approach, an integrative decision-making model was proposed to handle different kinds of decision-making problems. The decision-making process combined with a simple example was also given to describe the application of the proposed model. The conclusions are helpful to guide the construction and operation of S-SC by decision-makers. [Copyright &y& Elsevier]

By mining DNA microarray data bases at GenBank™, we identified up-regulation of membrane type 1 matrix metalloproteinase (MT1-MMP) in human primary and metastatic prostate cancer specimens as compared with nonmalignant prostate tissues. To explore the role of up-regulated MT1-MMP in early stage cancer progression, we have employed a three-dimensional cell culture model. Minimally invasive human prostate cancer cells (LNCaP) were transfected with Mu-green fluorescent protein (GFP) chimeric cDNA as compared with GFP cDNA, and morphologic and phenotypic changes were characterized. GFP-expressing LNCaP cells formed multicellular spheroids with cuboidal-like epithelial morphology, whereas MT1-GFP-expressing cells displayed a fibroblast-like morphology and a scattered growth pattern in type I collagen gels. Cell morphologic changes were accompanied by decreased epithelial markers and enhanced mesenchymal markers, consistent with epithelial-to-mesenchymal transition. MT1-MMP-induced morphologic change and cell scattering were abrogated by target inhibition of either the catalytic domain or the hemopexin domain. We further demonstrated that MT1-MMP-induced phenotypic changes were dependent upon up-regulation of Wnt5a, which has been implicated in epithelial-to-mesenchymal transition. We conclude that MT1-MMP plays an important role in early cancer dissemination by converting epithelial cells to migratory mesenchymal-like cells. [ABSTRACT FROM AUTHOR]

Objective To investigate the effectiveness and safety of various agents on paroxysmal atrial fibrillation in the elderly over 75 years old. Methods Totally 264 in-patients (75–91 years old, 185 males and 79 females) with atrial fibrillation history of less than 7 days were enrolled in this study. A total of 611 atrial fibrillation episodes were recorded, but 130 episodes (22.3%) of atrial fibrillation were auto-converted to sinus rhythm. The rest 481 episodes of atrial fibrillation were divided into six groups based on the drug used. Results The cardioversion ratio of atrial fibrillation were 9.5%, 46.9%, 71.7%, 55.9%, 32.7%, and 73.6% in control, cedilanid, amiodarone, propafenone, verapamil, and quinidine groups, respectively. Ventricular rate control were 5.4%, 83.6%, 84.9%, 77.9%, 78.8%, and 11.3% in those groups, respectively. The total effective rates of amiodarone and cedilanid groups were the highest. When the ventricular rate was controlled to below 90 bpm, the patients would almost complain of no discomfort. No severe side-effect was observed in each group. Conclusion Amiodarone and cedilanid may be the proper drugs for the treatment of paroxysmal atrial fibrillation in the elderly. The above antiarrhythmics in each therapeutic group were relatively safe and effective. [ABSTRACT FROM AUTHOR]

Proprotein convertases play an important role in tumorigenesis and invasiveness. Here, we report that a dibasic amino acid convertase, furin, directly cleaves proMMP-2 within the trans-Golgi network leading to an inactive form of matrix metalloproteinase-2 (MMP-2). Co-transfection of COS-1 cells with both proMMP-2 and furin cDNAs resulted in the cleavage of the N-terminal propeptide of proMMP-2. The molecular mass of cleaved MMP-2 (63 kDa), detected in both cell lysates and conditioned medium, is between the intermediate and fully activated forms of MMP-2 induced by membrane type 1-MMP. Furin-cleaved MMP-2 does not possess proteolytic activity as examined in a cell-free assay. Treatment of transfected cells with a furin inhibitor resulted in a dose-dependent inhibition of proMMP-2 cleavage; recombinant tissue inhibitor of metalloproteinase-2, which binds to the active site of membrane type 1-MMP, had no inhibitory effect. Site-directed mutagenesis of amino acids in the furin consensus recognition motif of proMMP-2(R69KPR72 ↓) prevented propeptide cleavage, thereby identifying the scissile bond and characterizing the basic amino acids required for cleavage. Other experimental observations were consistent with intracellular furin cleavage of proMMP-2 in the trans-Golgi network. The furin cleavage site in other proMMPs was examined. MMP-3, which contains the RXXR furin consensus sequence, was cleaved in furin co-transfected cells, whereas MMP-1, which lacks an RXXR consensus sequence, was not cleaved. In conclusion, we report the novel observation that furin can directly cleave the RXXR amino acid sequence in the propeptide domain of proMMP-2 leading to inactivation of the enzyme. [ABSTRACT FROM AUTHOR]

Substrate degradation and cell migration are key steps in cancer metastasis. Membrane-type 1-matrix metalloproteinase (MT1-MMP) has been linked with these processes. Using the fluorescein isothiocyanate (FITC)-labeled fibronectin degradation assay combined with the phagokinetic cell migration assay, structure. function relationships of MT1-MMP were studied. Our data indicate that MT1-MMP initiates substrate degradation and enhances cell migration; cell migration occurs as a concurrent but independent event. Using recombinant DNA approaches, we demonstrated that the hemopexin-like domain and a nonenzymatic component of the catalytic domain of MT1-MMP are essential for MT1-MMP-mediated cell migration. Because the cytoplasmic domain of MT1-MMP was not required for MT1MMP-mediated fibronectin degradation and cell migration, it is proposed that cross-talk between the hemopexin domain of MT1-MMP and adjacent cell surface molecules is responsible for outside-in signaling. Employing cDNAs encoding dominant negative mutations, we demonstrated that Rac1 participates in the MT1-MMP signal transduction pathway. These data demonstrated that each domain of MT1-MMP plays a distinct role in substrate degradation and cell migration. [ABSTRACT FROM AUTHOR]

• Brazilein was applied to the sciatic nerve injury model of BALB/c mice to observe the restoration of nerve myelin. • The expression of PSD-95 protein and mRNA in the spinal segment of L4-L6 was observed in the sciatic nerve injury model of BALB/c mice using Brazilein. • To observe the effect of Brazilein on nerve regeneration after peripheral nerve injury. To evaluate the local nerve myelin recovery and the expression of PSD-95 protein and mRNA in the L4–L6 segment of the spinal cord after applying Brazilein to sciatic nerve injury BALB/c mice model and investigate the regulatory effects of Brazilein on myelin recovery after peripheral nerve injury. A total of 160 BALB/c mice were selected to establish the unilateral sciatic nerve injury model and randomly divided into four groups: saline blank control, Brazilein high-dose, medium-dose, and low-dose. Mice were assessed at different time points (1 w, 2 w, 4 w, 8 w) after sciatic nerve injury for the sciatic functional index (SFI) and sciatic nerve function recovery of the injured side by myelin Luxol Fast Blue (LFB) staining of the sciatic nerve. In addition, immunohistochemistry, real time-PCR, and Western blot were used to detect the PSD-95 expression in the spinal cord L4–L6 segments of the injured sciatic nerve at each time point. The results of SFI and sciatic nerve function recovery, as well as, myelin LFB staining of the injured side indicated that all indexes of the Brazilein middle- and high-dose groups were significantly better than the low-dose and blank control groups at each time point. The PSD-95 expression in the L4–L6 segment of the spinal cord was statistically lower in the high- and medium-dose groups than in the low-dose and blank control groups at 1 w, 2 w, and 4 w, while the differences between the groups were not significant at 8 w. Brazilein inhibits PSD-95 activation in the corresponding segment of sciatic nerve spinal cord in BALB/c mice after sciatic nerve injury, thereby inhibiting the excessive expression of free radicals and promoting myelin regeneration. [ABSTRACT FROM AUTHOR]

Due to the poor anti-jamming performance, less gas species, low detection accuracy, short life, medium leaking or carbon monoxide poisoning and other defects that current sensors for gases dissolved in transformer oil have, a SOFC-based multi-component gas sensor has been designed. The physical, chemical and electrochemical mechanisms of gases in the SOFC have been analyzed, and the mathematical model which contains the static, dynamic and load effects has been established. And the model parameters have been optimized in this paper. The results showed that: (1) temperature is the decisive factor for the static characteristic of the sensor, and the accuracy of temperature should be controlled within ± 0.1 °C to achieve the 0.1 µL/L detection limit of C2H2. (2) The polarization resistance is inversely proportional to the input gas concentrations, while the open-circuit voltage is proportional to them. (3) The relationship between the short-circuit current and the square of input gas concentration is direct proportion, and the polarization resistance is the determinant of sensor dynamic characteristics. Finally, a gas experimental system has been built to verify the above conclusions. This gas sensor can realize the high-precision detection for multi-component gases dissolved in transformer oil effectively. [ABSTRACT FROM AUTHOR]

Interactions of bisphenol S, a new bisphenol analogue with bovine serum albumin and calf thymus DNA were investigated using different spectroscopic methods and molecular modeling calculation. According to the analysis of experimental and theoretical data, we concluded that hydrophobic interactions and hydrogen bonding primarily mediated the binding processes of bisphenol S with bovine serum albumin and DNA. In addition, the electrostatic force should not be excluded. Molecular modeling studies indicated that the binding site of bisphenol S to bovine serum albumin located in the subdomain IB, while bisphenol S was a groove binder of DNA. In addition, BPS did not obviously induce second structural changes of bovine serum albumin, but it induced a conformational change of calf thymus DNA. [ABSTRACT FROM AUTHOR]

Cytoskeleton disorganization is an early step in the activation process of matrix metalloproteinase 2 (MMP-2) by membrane type 1 MMP (MT1-MMP) but is also associated with endoplasmic reticulum (ER) dysfunction and subsequent cell death. Given evidence that the ER-embedded glucose-6-phosphate transporter (G6PT) regulates glioblastoma cell survival and that MT1-MMP is a key enzyme in the cancer cell invasive phenotype, we explored the molecular link between G6PT and MT1-MMP. Cytoskeleton-disrupting agents such as concanavalin A (ConA) and cytochalasin D triggered proMMP-2 activation and cell death in U87 glioma cells. ConA decreased G6PT gene expression, an event that was also observed in cells overexpressing the full-length recombinant MT1-MMP protein. Overexpression of a membrane-bound catalytically active but cytoplasmic domain-deleted MT1-MMP was unable to downregulate G6PT gene expression or to trigger necrosis. Gene silencing of MT1-MMP with small interfering RNA prevented proMMP-2 activation and induced G6PT gene expression. ConA inhibited Akt phosphorylation, whereas overexpression of recombinant G6PT rescued the cells from ConA-induced proMMP-2 activation and increased Akt phosphorylation. Altogether, new functions of MT1-MMP in cell death signaling may be linked to those of G6PT. Our study indicates a molecular signaling axis regulating the invasive phenotype of brain tumor cells and highlights a new "bioswitch" function for G6PT in cell survival. [ABSTRACT FROM AUTHOR]

With the appearance of the concept of virtual enterprise, it is necessary to develop a system that can support the collaborative work of multi-disciplinary groups distributed in different places. This paper puts forward a feature-based collaborative design system; briefly presents a model of collaborative design and the definition, classification and relationship of the features in this system; discusses key techniques related to realizing feature-based collaborative design in detail; and finally gives the architecture of the feature-based collaborative design system. [Copyright &y& Elsevier]

• In response to the challenge of maintaining stable and accurate relative positioning information for USVs and UAVs in unpredictable maritime weather conditions, this article introduces the UWB positioning system for the inaugural application in measuring the relative position of UAV landing on USVs. It also performs a quantitative analysis of the UWB positioning array's error, taking into account the impact of short deck baseline length and wave swaying, and proposes an adaptive filter solution. • A novel "surfing" roll and pitch stability control method for USV is proposed. This adjustment effectively minimizes the rolling and pitching response of the USV, consequently facilitating the smooth landing of the UAV. Simultaneously, the UAV evaluates its relative speed, position, and heading deviation in relation to the USV, and dynamically adjusts the expected docking control inputs and motion parameters using a fuzzy working condition table. Multiple autonomous landing experiments at sea have demonstrated the UAV's high landing accuracy and stability during the docking phase. • A task allocation method for efficient sea surface inspection using a heterogeneous unmanned system is proposed. Simulation tests of a USV equipped with four UAVs conducting sea surface inspection tasks are conducted in UE4 and Simulink. Within a 2km × 2km sea area, the surrounding inspection operation covers 74 % of the sea area and can be completed within 10 minutes. This method holds reference value for large-scale maritime search missions conducted by heterogeneous unmanned systems operating in sea and air environments. The incorporation of Unmanned Aerial Vehicles (UAVs) into sea surface inspection and complex water navigation tasks performed by Unmanned Surface Vessels (USVs) enhances the operational capabilities and task efficiency of heterogeneous systems. The autonomous docking of USV by UAV at sea serves as a foundational and vital element for facilitating collaborative tasks among unmanned systems. Faced with the problem that the UAV visual positioning USV deck is susceptible to interference from maritime meteorological conditions and the positioning accuracy of GPS is poor, this paper introduces the UWB positioning system and analyzes and solves the error disturbance term of its positioning array under the influence of sea sway for the first time. At the same time, due to the error problem caused by the small baseline of UWB installed on the deck, an adaptive Kalman filter that combines GPS speed information and UWB positioning data is proposed to reduce error. In light of the destabilizing effects resulting from the swaying of the USV deck during UAV docking, this study proposes a USV roll and pitch stability control strategy that incorporates environmental wind and wave data. Additionally, a UAV docking controller utilizing a fuzzy PID approach has been developed to facilitate secure and stable UAV takeoff and docking operations at sea. The effectiveness of the proposed algorithm was verified through sea docking experiments under various working conditions. Finally, in the context of the multi-target maritime inspection mission of heterogeneous unmanned systems, an exploratory improved VRP algorithm is proposed, allowing UAVs to quickly and efficiently complete sea surface inspection operations.The feasibility and operational efficiency of the cooperative mission system are tested through joint simulation using Simulink and UE4 in a high-fidelity environment. This provides a reference solution for future applications of heterogeneous unmanned systems in real maritime environments. [ABSTRACT FROM AUTHOR]

Laser interferometric gravitational wave detection in space holds the promise of being a new window to probe and address certain key problems in astronomy and cosmology, such as stellar evolution and galaxy formation in the early Universe, co-evolution of black holes and galaxies, etc. After two phases of feasibility study commissioned by Chinese Academy of Sciences and under the support of the Pioneer Explorer (Xiandao) Program, by considering relative merits between scientific significance and technological viability, a preliminary Chinese mission design with measurement waveband from mHz to 0.1 Hz is put forward, with the primary drivers being intermediate and supermassive black hole binaries at high redshift as well as intermediate mass ratio inspirals within dense star clusters in our local Universe. On the basis of the mission design, the scientific significance of gravitational wave detection in space as a possible new probe in astronomy is briefiy discussed. The primary science drivers together with the potential detection capability of the Chinese mission design will also be touched upon. [ABSTRACT FROM AUTHOR]

Although aspirin resistance is well reported in CVD, little is known about aspirin response in elderly patients with hyperhomocysteinaemia. The aim of the present study was to explore the prevalence of aspirin resistance in elderly patients with CVD and hyperhomocysteinaemia. A total of 370 elderly patients with CVD were recruited. The study included 216 patients with hyperhomocysteinaemia and 154 patients with normohomocysteinaemia receiving daily aspirin therapy (≥75 mg) over 1 month. The effect of aspirin was assessed using by light transmission aggregometry (LTA). Aspirin resistance was defined as ≥20% arachidonic acid induced aggregation according to LTA. Aspirin resistance was defined in 48 (13.0%) of 370 patients. The prevalence of aspirin resistance was higher in hyperhomocysteinaemic patients than normohomocysteinaemic patients (16.7% vs. 7.8%, odds ratio (OR) = 2.367; 95% confidence interval (CI) = 1.188-4.715, p = 0.012). In the multivariate logistic regression analysis, hyperhomocysteinaemia (OR = 2.406, 95% CI = 1.201-4.820, p = 0.013) was a significant risk factor for aspirin resistance. A significant number of CVD patients with hyperhomocysteinemia are resistant to aspirin therapy. Hyperhomocysteinemia is a significant risk factor for aspirin resistance in elderly patients with CVD. [ABSTRACT FROM AUTHOR]

The potassium channel Kv1.3 is an attractive pharmacological target for autoimmune diseases. Specific peptide inhibitors are key prospects for diagnosing and treating these diseases. Here, we identified the first scorpion Kunitz-type potassium channel toxin family with three groups and seven members. In addition to their function as trypsin inhibitors with dissociation constants of 140 nM for recombinant LmKTT-1a, 160 nM for LmKTT-1b, 124 nM for LmKTT-1c, 136 nM for BmKTT-1, 420 nM for BmKTT-2, 760 nM for BmKTT-3, and 107 nM for Hg1, all seven recombinant scorpion Kunitz-type toxins could block the Kv1.3 channel. Electrophysiological experiments showed that six of seven scorpion toxins inhibited ∼50-80% of Kv1.3 channel currents at a concentration of 1μM. The exception was rBm- KTT-3, which had weak activity. The IC50 values of rBmKTT-1, rBmKTT-2, and rHg1 for Kv1.3 channels were ∼129.7, 371.3, and 6.2 nM, respectively. Further pharmacological experiments indicated that rHg1 was a highly selective Kv1.3 channel inhibitor with weak affinity for other potassium channels. Different from classical Kunitz-type potassium channel toxins with N-terminal regions as the channel-interacting interfaces, the channel- interacting interface of Hg1 was in the C-terminal region. In conclusion, these findings describe the first scorpion Kunitztype potassium channel toxin family, of which a novel inhibitor, Hg1, is specific for Kv1.3 channels. Their structural and functional diversity strongly suggest that Kunitz-type toxins are a new source to screen and design potential peptides for diagnosing and treating Kv1.3-mediated autoimmune diseases. [ABSTRACT FROM AUTHOR]

Non-proteolytic activities of matrix metalloproteinases (MMPs) have recently been shown to impact cell migration, but the precise mechanism remains to be understood. We previously demonstrated that the hemopexin (PEX) domain of MMP-9 is a prerequisite for enhanced cell migration. Using a biochemical approach, we now report that dimerization of MMP-9 through the PEX domain appears necessary for MMP-9-enhanced cell migration. Following a series of substitution mutations within the MMP-9 PEX domain, blade IV was shown to be critical for homodimerization, whereas blade I was required for heterodimerization with CD44. Blade I and IV mutants showed diminished enhancement of cell migration compared with wild type MMP-9-transfected cells. Peptides mimicking motifs in the outermost strands of the first and fourth blades of the MMP-9 PEX domain were designed. These peptides efficiently blocked MMP-9 dimer formation and inhibited motility of COS-1 cells overexpressing MMP-9, HT-1080, and MDA-MB-435 cells. Using a shRNA approach, CD44 was found to be a critical molecule in MMP-9-mediated cell migration. Furthermore, an axis involving a MMP-9-CD44-EGFR signaling pathway in cell migration was identified using antibody array and specific receptor tyrosine kinase inhibitors. In conclusion, we dissected the mechanism of pro-MMP-9-enhanced cell migration and developed structure-based inhibitory peptides targeting MMP-9-mediated cell migration. [ABSTRACT FROM AUTHOR]

The potassium channel Kv1.3 is an attractive pharmacological target for immunomodulation of T cell-mediated autoimmune diseases. Potent and selective blockers of Kv1.3 are potential therapeutics for treating these diseases. Here we describe the design of a new peptide inhibitor that is potent and selective for Kv1.3. Three residues (Gly11 Ile28, and Asp33) of a scorpion toxin BmKTX were substituted by Arg11, Thr28, and His33, resulting in a new peptide, named ADWX-1. The ADWX-1 peptide blocked Kv 1.3 with picomolar affinity (IC50, 1.89 pM), showing a 100-fold increase in activity compared with the native BmKTX toxin. The ADWX-1 also displayed good selectivity on Kv1.3 over related Kv1.1 and Kv1.2 channels. Furthermore, alanine-scanning mutagenesis was carried out to map the functional residues of ADWX-1 in blocking Kv1.3. Moreover, computational simulation was used to build a structural model of the ADWX-1-Kv1.3 complex. This model suggests that all mutated residues are favorable for both the high potency and selectivity of ADWX-1 toward Kv1.3. While Arg11 of ADWX-1 interacts with Asp386 in Kv1.3, Thr28 and His33 of ADWX-1 locate right above the selectivity filter-S6 linker of Kv1.3. Together, our data indicate that the specific ADWX-1 peptide would be a viable lead in the therapy of T cell-mediated autoimmune diseases, and the successful design of ADWX-1 suggests that rational design based on the structural model of the peptide-channel complex should accelerate the development of diagnostic and therapeutic agents for human channelopathies. [ABSTRACT FROM AUTHOR]

Bone marrow-derived stromal cells BMSC) are avidly recruited by experimental vascularizing tumors, which implies that they must respond to tumor-derived growth factor cues. In fact, BMSC chemotaxis and cell survival are regulated, in part, by the membrane type-1 matrix metalloproteinase (MT1-MMP), an MMP also involved in pro-MMP-2 activation and in degradation of the extracellular matrix (ECM). Given that impaired chemotaxis was recently observed in bone marrow cells isolated from a glucose 6-phosphate transporter-deficient (G6PT-/-) mouse model, we sought to investigate the potential MT1-MMP/G6PT signaling axis in BMSC. We show that MT1-MMP-mediated activation of pro-MMP-2 by concanavalin A (ConA) correlated with an increase in the sub-G 1 cell cycle phase as well as with cell necrosis, indicative of a decrease in BMSC survival. BMSC isolated from Egr-1-/- mouse or MT1-MMP gene silencing in BMSC with small interfering RNA (siMT1-MMP) antagonized both the ConA-mediated activation of pro-MMP-2 and the induction of cell necrosis. Overexpression of recombinant full-length MT1-MMP triggered necrosis and this was signaled through the cytoplasmic domain of MT1-MMP. ConA inhibited both the gene and protein expression of G6PT, while overexpression of recombinant G6PT inhibited MT1-MMP-mediated pro-MMP-2 activation but could not rescue BMSC from ConA-induced cell necrosis. Cell chemotaxis in response to the tumorigenic growth factor sphingosine 1-phosphate was significantly abrogated in siMT1-MMP BMSC and in chlorogenic acid-treated BMSC. Altogether, we provide evidence for an MT1-MMP/G6PT signaling axis that regulates BMSC survival, ECM degradation, and mobilization. This may lead to optimized clinical applications that use BMSC as a platform for the systemic delivery of therapeutic or anti-cancer recombinant proteins in vivo. [ABSTRACT FROM AUTHOR]