Aberrant hyper-expression of the RNA binding protein GIGYF2 in endothelial cells modulates vascular aging and function.

Vascular endothelial cells (ECs) senescence plays a crucial role in vascular aging that promotes the initiation and progression of cardiovascular disease. The mutation of Grb10-interacting GYF protein 2 (GIGYF2) is strongly associated with the pathogenesis of aging-related diseases, whereas its role in regulating ECs senescence and dysfunction still remains elusive. In this study, we found aberrant hyperexpression of GIGYF2 in senescent human ECs and aortas of old mice. Silencing GIGYF2 in senescent ECs suppressed eNOS-uncoupling, senescence, and endothelial dysfunction. Conversely, in nonsenescent cells, overexpressing GIGYF2 promoted eNOS-uncoupling, cellular senescence, endothelial dysfunction, and activation of the mTORC1-SK61 pathway, which were ablated by rapamycin or antioxidant N-Acetyl-l-cysteine (NAC). Transcriptome analysis revealed that staufen double-stranded RNA binding protein 1 (STAU1) is remarkably downregulated in the GIGYF2-depleted ECs. STAU1 depletion significantly attenuated GIGYF2-induced cellular senescence, dysfunction, and inflammation in young ECs. Furthermore, we disclosed that GIGYF2 acting as an RNA binding protein (RBP) enhances STAU1 mRNA stability, and that the intron region of the late endosomal/lysosomal adaptor MAPK and mTOR activator 4 (LAMTOR4) could bind to STAU1 protein to upregulate LAMTOR4 expression. Immunofluorescence staining showed that GIGYF2 overexpression promoted the translocation of mTORC1 to lysosome. In the mice model, GIGYF2flox/flox Cdh-Cre+ mice protected aged mice from aging-associated vascular endothelium-dependent relaxation and arterial stiffness. Our work discloses that GIGYF2 serving as an RBP enhances the mRNA stability of STAU1 that upregulates LAMTOR4 expression through binding with its intron region, which activates the mTORC1-S6K1 signaling via recruitment of mTORC1 to the lysosomal membrane, ultimately leading to ECs senescence, dysfunction, and vascular aging. Disrupting the GIGYF2-STAU1-mTORC1 signaling cascade may represent a promising therapeutic approach against vascular aging and aging-related cardiovascular diseases.

MSC-derived exosomes protect against oxidative stress-induced skin injury via adaptive regulation of the NRF2 defense system.

Oxidative stress is a major cause of skin injury induced by damaging stimuli such as UV radiation. Currently, owing to their immunomodulatory properties, mesenchymal stem cell-derived exosomes (MSC-Exo), as a nanotherapeutic agent, have attracted considerable attention. Here, we investigated the therapeutic effects of MSC-Exo on oxidative injury in H2O2-stimulated epidermal keratinocytes and UV-irradiated wild type and nuclear factor-erythroid 2-related factor-2 (Nrf2) knocked down cell and animal models. Our findings showed that MSC-Exo treatment reduced reactive oxygen species generation, DNA damage, aberrant calcium signaling, and mitochondrial changes in H2O2-stimulated keratinocytes or UV-irradiated mice skin. Exosome therapy also improved antioxidant capacities shown by increased ferric ion reducing antioxidant power and glutathione peroxidase or superoxide dismutase activities in oxidative stress-induced cell and skin injury. In addition, it alleviated cellular and histological responses to inflammation and oxidation in cell or animal models. Furthermore, the NRF2 signaling pathway was involved in the antioxidation activity of MSC-Exo, while Nrf2 knockdown attenuated the antioxidant capacities of MSC-Exo in vitro and in vivo, suggesting that these effects are partially mediated by the NRF2 signaling pathway. These results indicate that MSC-Exo can repair oxidative stress-induced skin injury via adaptive regulation of the NRF2 defense system. Thus, MSC-Exo may be used as a potential dermatological nanotherapeutic agent for treating oxidative stress-induced skin diseases or disorders.

Diagnostic value of magnetic resonance and computed tomography colonography for the diagnosis of colorectal cancer: A systematic review and meta-analysis.

BACKGROUND: Surgical resection is the recommended procedure for colorectal cancer (CRC), but majority of the patients were diagnosed with advanced or metastatic CRC. Currently, there were inconsistent results about the diagnostic value of magnetic resonance colonography (MRC) and computed tomography colonography (CTC) in early CRC diagnosis. Our study conducted this meta-analysis to investigate the diagnostic value of MRC and CTC for CRC surveillance. METHODS: A comprehensive literature search was conducted in PubMed, Embase, and the Cochrane library to select relevant studies. The summary sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the area under the receiver operating characteristic curves (AUC) were calculated to evaluate the diagnostic value of MRC and CTC, respectively. RESULT: Twenty-five studies including 2985 individuals were selected in the final analysis. Eight studies evaluated the diagnostic value of MRC, and 17 studies assessed CTC. The summary sensitivity, specificity, PLR, NLR, DOR, and AUC in MRC for early detection of CRC were 0.98 (95% confidence interval, CI: 0.80-1.00), 0.94 (95% CI: 0.85-0.97), 15.48 (95% CI: 6.30-38.04), 0.02 (95% CI: 0.00-0.25), 115.09 (95% CI: 15.37-862.01), and 0.98 (95% CI: 0.97-0.99), respectively. In addition, the sensitivity, specificity, PLR, NLR, DOR, and AUC of CTC for diagnosing CRC were 0.97 (95% CI: 0.88-0.99), 0.99 (95% CI: 0.99-1.00), 154.11 (95% CI: 67.81-350.22), 0.03 (95% CI: 0.01-0.13), 642.51 (95% CI: 145.05-2846.02), and 1.00 (95% CI: 0.99-1.00). No significant differences were found between MRC and CTC for DOR in all the subsets. CONCLUSION: The findings of meta-analysis indicated that MRC and CTC have higher diagnostic values for early CRC diagnosis. However, the DOR for diagnosing CRC between MRC and CTC showed no significance.

Mesenchymal stem cell-derived exosomes as a nanotherapeutic agent for amelioration of inflammation-induced astrocyte alterations in mice.

Mesenchymal stem cell-derived exosomes (MSC-Exo) have robust anti-inflammatory effects in the treatment of neurological diseases such as epilepsy, stroke, or traumatic brain injury. While astrocytes are thought to be mediators of these effects, their precise role remains poorly understood. To address this issue, we investigated the putative therapeutic effects and mechanism of MSC-Exo on inflammation-induced alterations in astrocytes. Methods: Lipopolysaccharide (LPS)-stimulated hippocampal astrocytes in primary culture were treated with MSC-Exo, which were also administered in pilocarpine-induced status epilepticus (SE) mice. Exosomal integration, reactive astrogliosis, inflammatory responses, calcium signaling, and mitochondrial membrane potentials (MMP) were monitored. To experimentally probe the molecular mechanism of MSC-Exo actions on the inflammation-induced astrocytic activation, we inhibited the nuclear factor erythroid-derived 2, like 2 (Nrf2, a key mediator in neuroinflammation and oxidative stress) by sgRNA (in vitro) or ML385 (Nrf2 inhibitor) in vivo. Results: MSC-Exo were incorporated into hippocampal astrocytes as well as attenuated reactive astrogliosis and inflammatory responses in vitro and in vivo. Also, MSC-Exo ameliorated LPS-induced aberrant calcium signaling and mitochondrial dysfunction in culture, and SE-induced learning and memory impairments in mice. Furthermore, the putative therapeutic effects of MSC-Exo on inflammation-induced astrocytic activation (e.g., reduced reactive astrogliosis, NF-κB deactivation) were weakened by Nrf2 inhibition. Conclusions: Our results show that MSC-Exo ameliorate inflammation-induced astrocyte alterations and that the Nrf2-NF-κB signaling pathway is involved in regulating astrocyte activation in mice. These data suggest the promising potential of MSC-Exo as a nanotherapeutic agent for the treatment of neurological diseases with hippocampal astrocyte alterations.

Research progress in ultrasound use for the diagnosis and treatment of cerebrovascular diseases

Cerebrovascular diseases pose a serious threat to human survival and quality of life and represent a major cause of human death and disability. Recently, the incidence of cerebrovascular diseases has increased yearly. Rapid and accurate diagnosis and evaluation of cerebrovascular diseases are of great importance to reduce the incidence, morbidity and mortality of cerebrovascular diseases. With the rapid development of medical ultrasound, the clinical relationship between ultrasound imaging technology and the diagnosis and treatment of cerebrovascular diseases has become increasingly close. Ultrasound techniques such as transcranial acoustic angiography, doppler energy imaging, three-dimensional craniocerebral imaging and ultrasound thrombolysis are novel and valuable techniques in the study of cerebrovascular diseases. In this review, we introduce some of the new ultrasound techniques from both published studies and ongoing trials that have been confirmed to be convenient and effective methods. However, additional evidence from future studies will be required before some of these techniques can be widely applied or recommended as alternatives.

Ultrasound-Guided Intratumoral Radiofrequency Ablation Coagulation to Facilitate Meningioma Resection: Preliminary Experience.

OBJECTIVES: This study aimed to explore the feasibility and safety of intratumoral radiofrequency ablation (RFA) in meningioma resection. METHODS: This study was approved by the Xijing Ethics Committee, and informed consent was obtained from all of the patients. Thirteen patients with meningiomas were recruited in the Neurosurgery Department of Xijing Hospital. These patients were treated with intratumoral RFA and surgery. We also chose 13 patients with meningiomas treated with traditional surgery as the control group. Two-dimensional ultrasound, color Doppler flow imaging, contrast-enhanced ultrasound, and magnetic resonance imaging were used to identify the location, border, and blood supply of the meningiomas preoperatively and to assess the therapeutic effect intraoperatively. Finally, the meningiomas were dissected and removed by surgery. RESULTS: All procedures were technically successful without serious complications. Intraoperative ultrasound was able to provide a clear display of the location, shape, size, and boundary of the tumor and its relationship with other tissues and reveal the vascular distribution in and around the tumors. With intratumoral RFA, coagulative necrosis was induced, and the meningiomas became hard in texture with a decreased blood supply. Blood loss was significantly lower in the RFA group versus control group (320.0 ± 24.8 versus 390.4 ± 36.8 mL; P < .001). The RFA group spent fewer days in the hospital (6.0 ± 0.9 versus 7.0 ± 1.2 days; P = .022). However, the surgical time of the RFA group was relatively longer (3.5 ± 0.5 versus 3.0 ± 0.3 hours, P = .007). CONCLUSIONS: The application of intratumoral RFA in meningioma resection is effective and safe. It may be a useful adjunct for meningioma treatment.

Crocin Protects Podocytes Against Oxidative Stress and Inflammation Induced by High Glucose Through Inhibition of NF-κB.

BACKGROUND/AIMS: Diabetic nephropathy (DN) is a microangiopathic disease characterized by excessive urinary albumin excretion, which occurs in 30% of patients with diabetes mellitus. It is the second leading cause of end-stage renal diseases in China. Nuclear factor-kappa B (NF-κB) is reported to be closely correlated with the inflammation underlying diabetes-associated renal damage. Crocin, a plant-derived compound, has antioxidant properties that may inhibit NF-κB. METHODS: In the present study, we used a conditionally immortalized mouse podocyte cell line to explore whether crocin could effectively block albuminuria. Cells were incubated with 15 or 25 mM D-glucose to mimic diabetic conditions. The expression of Wilms tumor 1 (WT-1) and synaptopodin was evaluated to identify differentiated podocytes, and the expression of nephrin, podocin, and CD2ap was measured as markers of slit diaphragms, the main structures within the glomerular filtration barrier. RESULTS: The high-glucose conditions led to reduced nephrin, podocin, and CD2ap expression, which was prevented by pretreatment with crocin. The oxidative stress and pro-inflammatory response of podocytes associated with DN induced by high glucose were also reduced by crocin pretreatment. Phosphorylated IκBα (p-IκBα) expression induced by high glucose was also significantly decreased by crocin pretreatment. Moreover, pyrrolidine dithiocarbamate, a NF-κB inhibitor, pyrrolidine dithio carbamate, augmented the protective effects of crocin. CONCLUSION: Our results demonstrate a protective role of crocin against damage to podocytes and slit diaphragms under high-glucose conditions via inhibition of NF-κB. This study presents a potential therapy for DN and contributes to the understanding of the mechanism underlying DN.

MRI tracking of bone marrow mesenchymal stem cells labeled with ultra-small superparamagnetic iron oxide nanoparticles in a rat model of temporal lobe epilepsy.

Transplantation of bone marrow mesenchymal stem cells (BMSCs) is a promising approach for treatment of epilepsy. To our knowledge, there is little research on magnetic resonance imaging (MRI) tracking of BMSCs labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles in a rat model of temporal lobe epilepsy (TLE). In this study, BMSCs were pre-labeled with USPIO nanoparticles, and then the cell apoptosis, proliferation, surface antigens, and multipotency were investigated. Lithium chloride-pilocarpine induced TLE models were administered by USPIO-labeled BMSCs (U-BMSCs), BMSCs, and saline through lateral ventricle injection as the experimental group, control I group and control II group, respectively, followed by MRI examination, electroencephalography (EEG) and Prussian blue staining. The cell experimental results showed that the labeled USPIO did not affect the biological characteristics and multiple potential of BMSCs. The U-BMSCs can be detected using MRI in vitro and in vivo, and observed in the hippocampus and adjacent parahippocampal cortical areas of the epileptic model. Moreover, electroencephalographic results showed that transplanted U-BMSCs, as well as BMSCs, were capable of reducing the number of epileptiform waves significantly (P<0.01) compared with control II group. All of these findings suggest that it is feasible to track transplanted BMSCs using MRI in a rat model of TLE, and support that USPIO labeling is a valuable tool for cell tracking in the study of seizure disorders.

Genetically engineered bone marrow mesenchymal stem cells improve functional outcome in a rat model of epilepsy.

Bone marrow mesenchymal stem cells (BMSCs) hold a great promising approach for the treatment of epilepsy owing to their distinctive characteristics and multi-potency. However, there is little research focusing on the multi-potency of BMSCs in the treatment of epilepsy, the present study was designed to examine the influence of genetically engineered BMSCs (GE-BMSCs) on the functional outcome in a rat model of epilepsy. First, Hes1 gene of BMSCs was genetically engineered by RNA interference (RNAi), and then the GABAergic differentiation of GE-BMSCs was tested in vitro. Second, the lithium chloride-pilocarpine induced epileptic rats were administrated with the GE-BMSCs, the behavioral observation and electroencephalography (EEG) monitoring was employed to analyze the functional outcome on the epileptic model at different time points (day 7, day 14, day 21 and day 28), followed by histological verification. In vitro test showed that Hes1 silencing could promote BMSCs to differentiate into GABAergic neuron-like cells. In vivo test showed that GE-BMSCs graft could further improve the functional recovery of the epileptic rats, and the GABAergic differentiation of grafted GE-BMSCs was correlated with the functional recovery. Taken together, these data suggest that GE-BMSCs can improve the functional outcome in a rat model of epilepsy.

[Independent correlations of cerebral microstructural changes on DTI to general cognitive function and executive function in patients with subcortical ischemic vascular disease].

OBJECTIVE: To investigate whether DTI abnormalities in patients with nondemented subcortical ischemic vascular disease (SIVD) are correlated to general cognitive function and executive function independent of conventional MRI parameters. METHODS: Sixty-six SIVD patients including 30 with cognitive impairment without dementia (VCIND) and 36 with normal cognition (NCI) underwent DTI and cognitive assessment of the general cognitive function and executive function. Conventional MRI parameters and DTI parameters were measured within the white matter lesions (WMLs), normal-appearing white matter (NAWM) and normal-appearing gray matter (NAGM). The independent predictors of general cognitive function and executive function in SIVD patients was analyzed. RESULTS: NCI and VCIND patients showed significant differences in the periventricular WMLs, ADC valus in NAWM and WMLs of the centrum semiovale, and FA values in NAWM of the anterior periventricular. Except for ADC values of the caudate nucleus, ADC and FA values in the subcortical NAGM showed significant difference between the two groups. After controlling for age and education, PVLs and ADC values in the WMLs and NAWM of the centrum semiovale and putamen, and FA values in the anterior periventricular NAWM, WMLs and putamen showed significant correlations to MMSE; the number of lacunar infarcts, ADC values in posterior periventricular NAWM and caudate nucleus, and FA values in anterior periventricular NAWM and thalamus showed significant correlations to CDT. Multivariate analysis showed independent correlations of the ADC values in WMLs and NAWM of the centrum semiovale to MMSE, and demonstarted correlations of the ADC values of the caudate nucleus and number of lacunar infarcts to CDT. CONCLUSION: In nondemented SIVD subjects, the integrity of the white matter in the centrum semiovale strongly correlates to the general cognition, and the microstructural damage of the caudate nucleus head predicts executive function impairment independent of other MRI variables.

[Characteristics and in vitro imaging study of matrix metalloproteinase-2 targeting activable cell-penetrating peptide].

OBJECTIVE: To study invasively imaging MMP2-positive tumor cell by paramagnetic Gadolinium or fluorescein carried by a activable cell penetrating peptides. METHODS: To label Fluorescein-5-isothiocyanate (FITC) and gadopentetate with the activable cell-penetrating peptides by a solid-phase synthesis method. Identification by TOF mass spectrum (TOF-MS). Isoelectric point of the activable cell penetrating peptides is determined by disc electrophoresis. T1 relacion of gadopentetate labeled with the activable cell-penetrating peptides (B) in water were determined on 400 MHZ NMR. Human lung cancer cell lines: A549 were respectively stained by FITC labeled with ACPPs (A) or FITC alone. MMP2 expression and activity were determined by zymography. T1WI signal of A549 incubated with 120 nmol/ml B or Diethylenetriaminepentaacetic Acid-Gadolinium (Gd-DTPA) for different times were obtained by 1.5T MRI. The location of B in A549 was detected by Transmission Electron Microscopy. Visualization analysis and half-quantitative analysis were used to determine the signal characteristics. The ANOVA analysis and the paired samples t test were performed by SPSS 13.0. RESULTS: MALDI TOF-MS molecular weigh of A and B respectively is 3789.74 and 3911.93. Isoelectric point is 11.005T1 Relacion of 0.5 mmol/L Gd-DTPA and B at 17 degrees C respectively is (0.052 +/- 0.01) sec and (0.050 +/- 0.001) sec. Fluorescein uptake assays showed that A translocated into A549 but would be inhibited by MMP2 antibody. Zymography showed both active-MMP2 (67000) and pro-MMP2 (72000) expressed byA549. MR imaging showed A549 incubating with B had a high T(1) signal, and the signal of A549 incubating with Gd-DTPA is similar with that of the control group. Furthermore, ANOVA suggested that the T(1) signal intensity of A549 incubating with B was effected by incubating time (F = 267.569, P < 0.001) and increasing in a time-dependent fashion at the observed time. There is no difference between the T(1) signal intensity of A549 incubating with Gd-DTPA and the control group (P > 0.05). TEM showed A in cytoplasm and nucleus. CONCLUSION: The study in vitro suggests that the MMP-2 activable cell-penetrating peptides bearing contrast media can detect the MMP2-positive tumor cell.

Intercellular imaging by a polyarginine derived cell penetrating peptide labeled magnetic resonance contrast agent, diethylenetriamine pentaacetic acid gadolinium.

BACKGROUND: The cellular plasma membrane represents a natural barrier to many exogenous molecules including magnetic resonance (MR) contrast agent. Cell penetrating peptide (CPP) is used to internalize proteins, peptides, and radionuclide. This study was undertaken to assess the value of a new intracellular MR contrast medium, CPP labeled diethylenetriamine pentaacetic acid gadolinium (Gd-DTPA) in molecular imaging in vitro. METHODS: Fluorescein-5-isothiocyanate (FITC) and Gd-DTPA respectively labeled with CPP (FITC-CPP, Gd-DTPA-CPP) were synthesized by the solid-phase method. Human hepatic cancer cell line-HepG2 was respectively stained by FITC-CPP and FITC to observe the uptake and intracellular distribution. HepG2 was respectively incubated with 100 nmol/ml Gd-DTPA-CPP for 0, 10, 30, 60 minutes, and imaged by MR for studying the relationship between the incubation time and T(1)WI signal. The cytotoxicity to NIH3T3 fibroblasts cells was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide reduction assay (MTT). RESULTS: The molecular weights of CPP labeled imaging agents, which were determined by MALDI mass spectrometry (FITC-CPP MW = 2163.34, Gd-DTPA-CPP MW = 2285.99), were similar to the calculated molecular weights. Confocal microscopy suggested HepG2 translocated FITC-CPP in cytoplasm and nucleus independent with the incubation temperature. MR images showed HepG2 uptaken Gd-DTPA-CPP had a higher T(1) weighted imaging (T(1)WI) signal, and that the T(1)WI signal intensity was increasing in a time-dependent manner (r = 0.972, P = 0.001), while the signal intensity between the cells incubated by Gd-DTPA for 60 minutes and the controlled cells was not significantly different (P = 0.225). By MTT, all concentrations from 50 nmol/ml to 200 nmol/ml had no significant (F = 0.006, P = 1.000) effect on cell viability of mouse NIH3T3 fibroblasts, compared with the control group. CONCLUSIONS: The newly constructed CPP based on polyarginine can translocate cells by carrying FITC and MR contrast agent Gd-DTPA, and the intracellular concentrations are readily detectable by MR imaging, suggesting a new way for MR molecular imaging.

Application of cell penetrating peptide in magnetic resonance imaging of bone marrow mesenchymal stem cells.

Tracking the distribution and differentiation of stem cells by high-resolution imaging techniques would have significant clinical and research implications. In this study, a model cell-penetrating peptide was used to carry gadolinium particles for magnetic resonance imaging (MRI) of mesenchymal stem cells (MSCs). MSCs were isolated from rat bone marrow and identified by osteogenic differentiation in vitro. The cell-penetrating peptide labeled with fluorescein-5-isothiocyanate (FITC) and gadolinium was synthesized by a solid-phase peptide synthesis method. Fluorescein imaging analysis confirmed that this new peptide could internalize into the cytoplasm and nucleus at room temperature, 4 degrees and 37 degrees . Gadolinium were efficiently internalized into mesenchymal stem cells by the peptide in a time or concentration-dependent manner, resulting in intercellular shortening of longitudinal relaxation enhancements, which were obviously detected by 1.5 Tesla Magnetic Resonance Imaging. Cytotoxicity assay and flow cytometric analysis showed that the intercellular contrast medium incorporation did not affect cell viability at the tested concentrations. The in vitro experiment results suggested that the new constructed peptides could be a vector for tracking MSCs.

Paramagnetic particles carried by cell-penetrating peptide tracking of bone marrow mesenchymal stem cells, a research in vitro.

The ability to track the distribution and differentiation of stem cells by high-resolution imaging techniques would have significant clinical and research implications. In this study, a model cell-penetrating peptide was used to carry gadolinium particles for magnetic resonance imaging of the mesenchymal stem cells. The mesenchymal stem cells were isolated from rat bone marrow by Percoll and identified by osteogenic differentiation in vitro. The cell-penetrating peptides labeled with fluorescein-5-isothiocyanate and gadolinium were synthesized by a solid-phase peptide synthesis method and the relaxivity of cell-penetrating peptide-gadolinium paramagnetic conjugate on 400 MHz nuclear magnetic resonance was 5.7311 +/- 0.0122 m mol(-1) s(-1), higher than that of diethylenetriamine pentaacetic acid gadolinium (p < 0.05). Fluorescein imaging confirmed that this new peptide could internalize into the cytoplasm and nucleus. Gadolinium was efficiently internalized into mesenchymal stem cells by the peptide in a time- or concentration-dependent fashion, resulting in intercellular T1 relaxation enhancement, which was obviously detected by 1.5 T magnetic resonance imaging. Cytotoxicity assay and flow cytometric analysis showed the intercellular contrast medium incorporation did not affect cell viability and membrane potential gradient. The research in vitro suggests that the newly constructed peptides could be a vector for tracking mesenchymal stem cells.