Aptamer-modified magnetic nanoprobe for molecular MR imaging of VEGFR2 on angiogenic vasculature

Nucleic acid-based aptamers have been developed for the specific delivery of diagnostic nanoprobes. Here, we introduce a new class of smart imaging nanoprobe, which is based on hybridization of a magnetic nanocrystal with a specific aptamer for specific detection of the angiogenic vasculature of glioblastoma via magnetic resonance (MR) imaging. The magnetic nanocrystal imaging core was synthesized using the thermal decomposition method and enveloped by carboxyl polysorbate 80 for water solubilization and conjugation of the targeting moiety. Subsequently, the surface of the carboxylated magnetic nanocrystal was modified with amine-functionalized aptamers that specifically bind to the vascular growth factor receptor 2 (VEGFR2) that is overexpressed on angiogenic vessels. To assess the targeted imaging potential of the aptamer-conjugated magnetic nanocrystal for VEGFR2 markers, the magnetic properties and MR imaging sensitivity were investigated using the orthotopic glioblastoma mouse model. In in vivo tests, the aptamer-conjugated magnetic nanocrystal effectively targeted VEGFR2 and demonstrated excellent MR imaging sensitivity with no cytotoxicity.     

Integrated Multi-Omics Investigations of Metalloproteinases in Colon Cancer: Focus on MMP2 and MMP9

Colorectal cancer (CRC) develops by genetic and epigenetic alterations. However, the molecular mechanisms underlying metastatic dissemination remain unclear and could benefit from multi-omics investigations of specific protein families. Matrix metalloproteinases (MMPs) are proteolytic enzymes involved in ECM remodeling and the processing of bioactive molecules. Increased MMP expression promotes the hallmarks of tumor progression, including angiogenesis, invasion, and metastasis, and is correlated with a shortened survival. Nevertheless, the collective role and the possible coordination of MMP members in CRC are poorly investigated. Here, we performed a multi-omics analysis of MMP expression in CRC using data mining and experimental investigations. Several databases were used to deeply mine different expressions between tumor and normal tissues, the genetic and epigenetic alterations, the prognostic value as well as the interrelationships with tumor immune-infiltrating cells (TIICs). A special focus was placed on to MMP2 and MMP9: their expression was correlated with immune markers and the interaction network of co-expressed genes disclosed their implication in epithelial to mesenchymal transition (EMT) and immune response. Finally, the activity levels of MMP2 and MMP9 in a cohort of colon cancer samples, including tissues and the corresponding sera, was also investigated by zymography. Our findings suggested that MMPs could have a high potency, as they are targeted in colon cancer, and might serve as novel biomarkers, especially for their involvement in the immune response. However, further studies are needed to explore the detailed biological functions and molecular mechanisms of MMPs in CRC, also in consideration of their expression and different regulation in several tissues.     

Low-Dose Empagliflozin Improves Systolic Heart Function after Myocardial Infarction in Rats: Regulation of MMP9, NHE1, and SERCA2a

The effects of the selective sodium-glucose cotransporter 2 (SGLT2) inhibitor empagliflozin in low dose on cardiac function were investigated in normoglycemic rats. Cardiac parameters were measured by intracardiac catheterization 30 min after intravenous application of empagliflozin to healthy animals. Empagliflozin increased the ventricular systolic pressure, mean pressure, and the max dP/dt (p < 0.05). Similarly, treatment with empagliflozin (1 mg/kg, p.o.) for one week increased the cardiac output, stroke volume, and fractional shortening (p < 0.05). Myocardial infarction (MI) was induced by ligation of the left coronary artery. On day 7 post MI, empagliflozin (1 mg/kg, p.o.) improved the systolic heart function as shown by the global longitudinal strain (−21.0 ± 1.1% vs. −16.6 ± 0.7% in vehicle; p < 0.05). In peri-infarct tissues, empagliflozin decreased the protein expression of matrix metalloproteinase 9 (MMP9) and favorably regulated the cardiac transporters sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA2a) and sodium hydrogen exchanger 1 (NHE1). In H9c2 cardiac cells, empagliflozin decreased the MMP2,9 activity and prevented apoptosis. Empagliflozin did not alter the arterial stiffness, blood pressure, markers of fibrosis, and necroptosis. Altogether, short-term treatment with low-dose empagliflozin increased the cardiac contractility in normoglycemic rats and improved the systolic heart function in the early phase after MI. These effects are attributed to a down-regulation of MMP9 and NHE1, and an up-regulation of SERCA2a. This study is of clinical importance because it suggests that a low-dose treatment option with empagliflozin may improve cardiovascular outcomes post-MI. Down-regulation of MMPs could be relevant to many remodeling processes including cancer disease.     

Modulating the ERK1/2–MMP1 Axis through Corosolic Acid Inhibits Metastasis of Human Oral Squamous Cell Carcinoma Cells

Corosolic acid (CA; 2α-hydroxyursolic acid) is a natural pentacyclic triterpenoid with antioxidant, antitumour and antimetastatic activities against various tumour cells during tumourigenesis. However, CA’s antitumour effect and functional roles on human oral squamous cell carcinoma (OSCC) cells are utterly unknown. In this study, our results demonstrated that CA significantly exerted an inhibitory effect on matrix metalloproteinase (MMP)1 expression, cell migration and invasion without influencing cell growth or the cell cycle of human OSCC cells. The critical role of MMP1 was confirmed using the GEPIA database and showed that patients have a high expression of MMP1 and have a shorter overall survival rate, confirmed on the Kaplan–Meier curve assay. In the synergistic inhibitory analysis, CA and siMMP1 co-treatment showed a synergically inhibitory influence on MMP1 expression and invasion of human OSCC cells. The ERK1/2 pathway plays an essential role in mediating tumour progression. We found that CA significantly inhibits the phosphorylation of ERK1/2 dose-dependently. The ERK1/2 pathway played an essential role in the CA-mediated downregulation of MMP1 expression and in invasive motility in human OSCC cells. These findings first demonstrated the inhibitory effects of CA on OSCC cells’ progression through inhibition of the ERK1/2–MMP1 axis. Therefore, CA might represent a novel strategy for treating OSCC.     

MMP9 Differentially Regulates Proteins Involved in Actin Polymerization and Cell Migration during TGF-β-Induced EMT in the Lens

Fibrotic cataracts have been attributed to transforming growth factor-beta (TGF-β)-induced epithelial-to-mesenchymal transition (EMT). Using mouse knockout (KO) models, our laboratory has identified MMP9 as a crucial protein in the TGF-β-induced EMT process. In this study, we further revealed an absence of alpha-smooth muscle actin (αSMA) and filamentous-actin (F-actin) stress fibers in MMP9KO mouse lens epithelial cell explants (LECs). Expression analysis using NanoString revealed no marked differences in αSMA (ACTA2) and beta-actin (β-actin) (ACTB) mRNA between the lenses of TGF-β-overexpressing (TGF-βtg) mice and TGF-βtg mice on a MMP9KO background. We subsequently conducted a protein array that revealed differential regulation of proteins known to be involved in actin polymerization and cell migration in TGF-β-treated MMP9KO mouse LECs when compared to untreated controls. Immunofluorescence analyses using rat LECs and the novel MMP9-specific inhibitor, JNJ0966, revealed similar differential regulation of cortactin, FAK, LIMK1 and MLC2 as observed in the array. Finally, a reduction in the nuclear localization of MRTF-A, a master regulator of cytoskeletal remodeling during EMT, was observed in rat LECs co-treated with JNJ0966 and TGF-β. In conclusion, MMP9 deficiency results in differential regulation of proteins involved in actin polymerization and cell migration, and this in turn prevents TGF-β-induced EMT in the lens.     

细胞Zn2+荧光探针研究进展

主要对近年来测定细胞内游离Zn^2＋的荧光探针进行较详细地评述，并对其化学规律、性质和其优缺点进行了讨论。     

Chronic Monocular Deprivation Reveals MMP9-Dependent and -Independent Aspects of Murine Visual System Plasticity

The deletion of matrix metalloproteinase MMP9 is combined here with chronic monocular deprivation (cMD) to identify the contributions of this proteinase to plasticity in the visual system. Calcium imaging of supragranular neurons of the binocular region of primary visual cortex (V1b) of wild-type mice revealed that cMD initiated at eye opening significantly decreased the strength of deprived-eye visual responses to all stimulus contrasts and spatial frequencies. cMD did not change the selectivity of V1b neurons for the spatial frequency, but orientation selectivity was higher in low spatial frequency-tuned neurons, and orientation and direction selectivity were lower in high spatial frequency-tuned neurons. Constitutive deletion of MMP9 did not impact the stimulus selectivity of V1b neurons, including ocular preference and tuning for spatial frequency, orientation, and direction. However, MMP9^−/− mice were completely insensitive to plasticity engaged by cMD, such that the strength of the visual responses evoked by deprived-eye stimulation was maintained across all stimulus contrasts, orientations, directions, and spatial frequencies. Other forms of experience-dependent plasticity, including stimulus selective response potentiation, were normal in MMP9^−/− mice. Thus, MMP9 activity is dispensable for many forms of activity-dependent plasticity in the mouse visual system, but is obligatory for the plasticity engaged by cMD.     

细胞Zn2+荧光探针研究进展

本文主要对近年来测定细胞内游离Zn2 的荧光探针进行较详细地评述,并对其化学规律、性质和其优缺点进行了讨论.     

Local Insulin-Derived Amyloidosis Model Confronted with Silymarin: Histological Insights and Gene Expression of MMP,TNF-α, and IL-6

Amyloidosis is a heterogeneous group of protein deposition diseases associated with the presence of amyloid fibrils in tissues. Analogs of insulin that are used for treating diabetic patients (including regular insulin) can form amyloid fibrils, both in vitro and in vivo as reported in patients. The main purpose of this study was the induction of localized insulin-generated amyloidosis and the observation of silymarin effects on this process. In order to obtain amyloid structures, regular insulin was incubated at 37 °C for 24 h. Congo red absorbance and transmission electron microscopy images validated the formation of amyloid fibrils. Those fibrils were then injected subcutaneously into rats once per day for 6, 12 or 18 consecutive days in the presence or absence of silymarin, and caused development of firm waxy masses. These masses were excised and stained with Hematoxylin and Eosin, Congo red and Thioflavin S. Histological examination showed adipose cells and connective tissue in which amyloid deposition was visible. Amyloids decreased in the presence of silymarin, and the same effect was observed when silymarin was added to normal insulin and injected subsequently. Furthermore, plasma concentrations of MMP2, TNF-α, and IL-6 inflammatory factors were measured, and their gene expression was locally assessed in the masses by immunohistochemistry. All three factors increased in the amyloidosis state, while silymarin had an attenuating effect on their plasma levels and gene expression. In conclusion, we believe that silymarin could be effective in counteracting insulin-generated local amyloidosis.     

Sodium 4-Phenylbutyrate Reduces Ocular Hypertension by Degrading Extracellular Matrix Deposition via Activation of MMP9

Ocular hypertension (OHT) is a serious adverse effect of the widely prescribed glucocorticoid (GC) therapy and, if left undiagnosed, it can lead to glaucoma and complete blindness. Previously, we have shown that the small chemical chaperone, sodium-4-phenylbutyrate (PBA), rescues GC-induced OHT by reducing ocular endoplasmic reticulum (ER) stress. However, the exact mechanism of how PBA rescues GC-induced OHT is not completely understood. The trabecular meshwork (TM) is a filter-like specialized contractile tissue consisting of TM cells embedded within extracellular matrix (ECM) that controls intraocular pressure (IOP) by constantly regulating aqueous humor (AH) outflow. Induction of abnormal ECM deposition in TM is a hallmark of GC-induced OHT. Here, we investigated whether PBA reduces GC-induced OHT by degrading abnormal ECM deposition in TM using mouse model of GC-induced OHT, ex vivo cultured human TM tissues and primary human TM cells. We show that topical ocular eye drops of PBA (1%) significantly lowers elevated IOP in mouse model of GC-induced OHT. Importantly, PBA prevents synthesis and deposition of GC-induced ECM in TM. We report for the first time that PBA can degrade existing abnormal ECM in normal human TM cells/tissues by inducing matrix metalloproteinase (MMP)9 expression and activity. Furthermore, inhibition of MMPs activity by chemical-inhibitor (minocycline) abrogated PBA’s effect on ECM reduction and its associated ER stress. Our study indicates a non-chaperone activity of PBA via activation of MMP9 that degrades abnormal ECM accumulation in TM.     

An Exploratory Study Provides Insights into MMP9 and Aβ Levels in the Vitreous and Blood across Different Ages and in a Subset of AMD Patients

Matrix metalloproteinase-9 (MMP9) and total amyloid-beta (Aβ) are prospective biomarkers of ocular ageing and retinopathy. These were quantified by ELISA in the vitreous and blood from controls (n = 55) and in a subset of age-related macular degeneration (AMD) patients (n = 12) for insights and possible additional links between the ocular and systemic compartments. Vitreous MMP9 levels in control and AMD groups were 932.5 ± 240.9 pg/mL and 813.7 ± 157.6 pg/mL, whilst serum levels were 2228 ± 193 pg/mL and 2386.8 ± 449.4 pg/mL, respectively. Vitreous Aβ in control and AMD groups were 1173.5 ± 117.1 pg/mL and 1275.6 ± 332.9 pg/mL, whilst plasma Aβ were 574.3 ± 104.8 pg/mL and 542.2 ± 139.9 pg/mL, respectively. MMP9 and Aβ showed variable levels across the lifecourse, indicating no correlation to each other or with age nor AMD status, though the smaller AMD cohort was a limiting factor. Aβ and MMP9 levels in the vitreous and blood were unrelated to mean arterial pressure. Smoking, another modifiable risk, showed no association with vitreous Aβ. However, smoking may be linked with vitreous (p = 0.004) and serum (p = 0.005) MMP9 levels in control and AMD groups, though this did not reach our elevated (p = 0.001) significance. A bioinformatics analysis revealed promising MMP9 and APP/Aβ partners for further scrutiny, many of which are already linked with retinopathy.     

H2O2基燃料电池阴极催化剂的研究进展

本文综述了燃料电池中H2O2电还原催化剂的研究,其主要集中在贵金属、过渡金属的大环化合物、酶以及非贵金属氧化物,其中研究非贵金属氧化物作为H2O2电还原的催化剂将是未来发展的方向.     

适用于N_2／CO_2气源MgO－C供气元件的研究

对采用镁砂晶粒平均粒径在４００～６００ｕｒｎ，石墨纯度达到Ｃ≥９８％，石墨的细度在０．１４７～０．１７８ｍｍ，金属加入物以铝粉与硅粉复合形式加入，生产出的ＭｇＯ－Ｃ供气元件性能较好。同时研究了碳化硼和固体结合剂对该材质的抗氧化性和高温强度等的影响。     

Near-infrared fluorescent probe for fast track of cyclooxygenase-2 in Golgi apparatus in cancer cells

Cyclooxygenase-2 (COX-2) has been used as an excellent traceable biomarker, and exists maximally in Golgi apparatus (Cancer cells). Celecoxib (CCB) is a selective inhibitor for COX-2, and has been used as one of non-steroidal anti-inflammatory drug. Herein we report the conjugation of nile blue (NB) with CCB via a six-carbon linkage to form a fluorescence probe NB-C6-CCB for the detection of COX-2. NB-C6-CCB displays strong fluorescence with the emission peak centered at near-infrared wavelength (700 nm) in tumor cells or tumor tissues with high expression of COX-2. Importantly, NB-C6-CCB can discriminate cancer cells (MCF-7) fluorescence intensity from normal ones (COS-7) in the co-culture medium under confocal microscope. Subcellular localization of the NB-C6-CCB preferentially points to the Golgi apparatus and increases the fluorescent intensity. The competitive analysis (with CCB) and Native-PAGE analysis confirmed that NB-C6-CCB shows selective binding affinity towards COX-2 enzyme. Competitive analysis with CCB (flow cytometry assay) revealed the fluorescence intensity fluctuation due to pretreatment of CCB with different concentrations, indicating that the NB-C6-CCB is a precise or sensitive probe for the COX-2. Tumor tissue (depth: 500 µm), organs and mice imaging tests show excellent near-infrared visualization, specific localization and identification of tumors.     

小鼠血清乙型肝炎病毒前S2抗体间接ELISA检测方法的建立

目的建立小鼠血清乙型肝炎病毒(Hepatitis B virus,HBV)前S2抗体间接ELISA检测方法。方法以HBV前S2(1～26)多肽包被酶标板,利用方阵滴定法确定间接ELISA法的最适工作条件,验证该方法的精密度、灵敏度和特异性,并与商品化试剂盒进行比较。结果确定最佳抗原包被浓度为2μg/ml;血清稀释度为1︰10,37℃反应30 min;HRP标记的羊抗小鼠IgG最佳稀释度为1︰10 000,37℃反应30 min;TMB底物37℃显色15 min,以2.1×阴性对照血清A450均值(阴性对照血清小于0.05时按0.05计算)为Cut-off值。该方法具有良好的试验内和试验间精密度;与商品化试剂盒比较,灵敏度为100%,特异性为97.3%,二者符合率为98.5%。结论已成功建立HBV前S2抗体间接ELISA方法,可用于小鼠血清中前S2抗体的检测。     

油田用纳米荧光类示踪剂发展现状及前景

随着油田开发进入中后期,油田对示踪剂技术的需求越来越大.示踪剂技术已由之前的单井单层注入,逐步向多井、多层位、多轮次、区块整体注入转变,而目前常用的示踪剂种类已无法满足现场需求.近几年,纳米技术作为一项前沿技术,在油气行业中已经得到应用,同时纳米荧光示踪技术在医学、生物学和水处理等领域已得到广泛应用.对油田用纳米荧光类...