MG53 E3 Ligase-Dead Mutant Protects Diabetic Hearts From Acute Ischemic/Reperfusion Injury and Ameliorates Diet-Induced Cardiometabolic Damage.

Cardiometabolic diseases, including diabetes and its cardiovascular complications, are the global leading causes of death, highlighting a major unmet medical need. Over the past decade, mitsugumin 53 (MG53), also called TRIM72, has emerged as a powerful agent for myocardial membrane repair and cardioprotection, but its therapeutic value is complicated by its E3 ligase activity, which mediates metabolic disorders. Here, we show that an E3 ligase-dead mutant, MG53-C14A, retains its cardioprotective function without causing metabolic adverse effects. When administered in normal animals, both the recombinant human wild-type MG53 protein (rhMG53-WT) and its E3 ligase-dead mutant (rhMG53-C14A) protected the heart equally from myocardial infarction and ischemia/reperfusion (I/R) injury. However, in diabetic db/db mice, rhMG53-WT treatment markedly aggravated hyperglycemia, cardiac I/R injury, and mortality, whereas acute and chronic treatment with rhMG53-C14A still effectively ameliorated I/R-induced myocardial injury and mortality or diabetic cardiomyopathy, respectively, without metabolic adverse effects. Furthermore, knock-in of MG53-C14A protected the mice from high-fat diet-induced metabolic disorders and cardiac damage. Thus, the E3 ligase-dead mutant MG53-C14A not only protects the heart from acute myocardial injury but also counteracts metabolic stress, providing a potentially important therapy for the treatment of acute myocardial injury in metabolic disorders, including diabetes and obesity.

Non-isolated high step-up DC/DC power converter with coupled-inductor.

This paper presents a non-isolated single switch converter with high voltage gain. Its circuit topology is combined with coupled-inductor, clamp circuit, and voltage lift capacitor techniques. The proposed converter has several advantages: First, the circuit is controlled by only single pulse width modulation (PWM) for the power switch, which keeps the circuit simple. Secondly, the proposed converter is used as a clamping circuit,which let the energy of the leakage inductance can be circulated to the capacitor, so that the voltage spike on the active switch can be suppressed, and improves efficiency. This paper will introduce the principle of action, theoretical analysis, and experimental waveform in order. Finally, in the case of input voltage of 48 V, output voltage of 400 V, and output power of 1 kW, the performance of the proposed converter is verified. As a result, the maximum efficiency is up to 96.5% and full load efficiency is 92.3%.

Fluorofenidone attenuates bleomycin-induced pulmonary fibrosis by inhibiting eukaryotic translation initiation factor 3a (eIF3a) in rats.

Fluorofenidone is a novel derivative of l-mimosine. It has remarkable anti-fibrotic properties. In this study, we established that fluorofenidone ameliorates pulmonary fibrosis (PF) both in vivo and in vitro by specifically inhibiting the expression of eukaryotic translation initiation factor 3a (eIF3a). eIF3a plays an important role in the development and progression of PF. An animal model of PF was induced by intratracheal instillation of bleomycin (5mg/kg) in rats. Rats were orally administered with fluorofenidone (250, 500 mg/kg/d·[i.g.]) and pirfenidone (500 mg/kg/d·[i.g.]) for 28 days. Primary pulmonary fibroblasts were cultured to determine the effect of fluorofenidone on TGF-ß1-induced (5 ng/ml) proliferation and differentiation of fibroblasts. The expression/level of eIF3a, TGF-ß1, α-SMA, collagen I, and collagen III were analyzed by ELISA, real-time PCR, and western blot. The cell proliferation rate was determined by MTS assay. The results indicate that fluorofenidone significantly improves the pathological changes in lung tissues and reduces the deposition of collagen by inhibiting eIF3a in rats with bleomycin-induced PF. Moreover, in a culture of pulmonary fibroblasts, fluorofenidone decreased the up-regulation of TGF-ß1-induced eIF3a by inhibiting the proliferation of cells and reducing the expression of α-SMA, collagen I, and collagen III. These findings suggest that eIF3a is a new and special target of fluorofenidone, which could be potentially used in the development of a drug that treats PF.

Role of eukaryotic translation initiation factors 3a in hypoxia-induced right ventricular remodeling of rats.

AIM: Eukaryotic translation initiation factors 3a (eIF3a) is involved in regulating cell cycle, cell division, growth and differentiation. Previous studies suggest a role of eIF3a on fibrosis disease and cellular proliferation and differentiation of fibroblasts. The present study aims to investigate the role of eIF3a on hypoxia-induced right ventricular (RV) remodeling and underlying mechanism. MAIN METHODS: RV remodeling was induced by hypoxia (10% O2, 3 weeks) in rats. Primary cardiac fibroblasts were cultured in vitro and their proliferation was investigated by MTS and EdU incorporation method. eIF3a knockdown was conducted by eIF3a siRNA. The expression/level of TGF-ß1, eIF3a, p27 and α-SMA, collagen-I, collagen-III, ANP and BNP were analyzed by ELISA, real-time PCR or Western blot. KEY FINDINGS: The expression of eIF3a was obviously increased in right ventricle of RV remodeling rats accompanied by up-regulation of α-SMA and collagens. In cultured cardiac fibroblasts, application of exogenous TGF-ß1-induced cellular proliferation and differentiation concomitantly with up-regulation of eIF3a expression and down-regulation of p27 expression. The effects of TGF-ß1-induced proliferation and up-regulation of α-SMA and collagen in cardiac fibroblasts were abolished by eIF3a siRNA. eIF3a siRNA reversed TGF-ß1 induced down-regulation of p27 expression. SIGNIFICANCE: The eIF3a plays a crucial role in hypoxia-induced RV remodeling by regulating TGF-ß1-induced proliferation and differentiation of cardiac fibroblasts, which is mediated via eIF3a/p27 pathway.

Nanocontact Disorder in Nanoelectronics for Modulation of Light and Gas Sensitivities.

To fabricate reliable nanoelectronics, whether by top-down or bottom-up processes, it is necessary to study the electrical properties of nanocontacts. The effect of nanocontact disorder on device properties has been discussed but not quantitatively studied. Here, by carefully analyzing the temperature dependence of device electrical characteristics and by inspecting them with a microscope, we investigated the Schottky contact and Mott's variable-range-hopping resistances connected in parallel in the nanocontact. To interpret these parallel resistances, we proposed a model of Ti/TiOx in the interface between the metal electrodes and nanowires. The hopping resistance as well as the nanocontact disorder dominated the total device resistance for high-resistance devices, especially at low temperatures. Furthermore, we introduced nanocontact disorder to modulate the light and gas responsivities of the device; unexpectedly, it multiplied the sensitivities compared with the intrinsic sensitivity of the nanowires. Our results improve the collective understanding of electrical contacts to low-dimensional semiconductor devices and will aid performance optimization in future nanoelectronics.

Pure electron-electron dephasing in percolative aluminum ultrathin film grown by molecular beam epitaxy.

We have successfully grown ultrathin continuous aluminum film by molecular beam epitaxy. This percolative aluminum film is single crystalline and strain free as characterized by transmission electron microscopy and atomic force microscopy. The weak anti-localization effect is observed in the temperature range of 1.4 to 10 K with this sample, and it reveals that, for the first time, the dephasing is purely caused by electron-electron inelastic scattering in aluminum.

Role of eukaryotic translation initiation factor 3a in bleomycin-induced pulmonary fibrosis.

Eukaryotic translation initiation factor 3a (eIF3a) is a multifunctional protein and plays an important role in regulation of cellular function including proliferation and differentiation. In the present study, we tested the function of eIF3a in pulmonary fibrosis. Pulmonary fibrosis was induced by intratracheal instillation of bleomycin (5mg/kg) in rats. Primary pulmonary fibroblasts were cultured for proliferation investigation by BrdU incorporation method and flow cytometry. The expression/level of eIF3a, TGF-ß1, ERK1/2 and α-SMA were analyzed by ELISA, real-time PCR or western blot. Results showed that the expression of eIF3a was obviously increased in lungs of pulmonary fibrosis rats accompanied by up-regulation of α-SMA and collagens. In cultured pulmonary fibroblasts, application of exogenous TGF-ß1 induced cell proliferation and differentiation concomitantly with up-regulation of eIF3a expression and ERK1/2 phosphorylation. The effects of TGF-ß1-induced proliferation of fibroblasts and up-regulation of α-SMA were abolished by eIF3a siRNA. TGF-ß1-induced eIF3a expression was reversed in the presence of PD98059, an inhibitor of ERK1/2. These findings suggest that eIF3a plays an important role in bleomycin-induced pulmonary fibrosis by regulating pulmonary fibroblasts׳ function, and up-regulation of eIF3a induced by TGF-ß1 is mediated via the ERK1/2 pathway.

Involvement of glutamate-cystine/glutamate transporter system in aspirin-induced acute gastric mucosa injury.

Large-dose or long-term use of aspirin tends to cause gastric mucosa injury, which is recognized as the major side effect of aspirin. It has been demonstrated that glutamate exerts a protective effect on stomach, and the level of glutamate is critically controlled by cystine/glutamate transporter (Xc(-)). In the present study, we investigated the role of glutamate-cystine/glutamate transporter system in aspirin-induced acute gastric mucosa injury in vitro and in vivo. Results showed that in human gastric epithelial cells, aspirin incubation increased the activity of LDH and the number of apoptotic cells, meanwhile down-regulated the mRNA expression of Xc(-) accompanied with decreased glutamate release. Similar results were seen in a rat model. In addition, exogenous l-glutamate attenuated the gastric mucosa injury and cell damage induced by aspirin both in vitro and in vivo. Taken together, our results demonstrated that acute gastric mucosa injury induced by aspirin is related to reduction of glutamate-cystine/glutamate transporter system activity.

Effect of In/Al ratios on structural and optical properties of InAlN films grown on Si(100) by RF-MOMBE.

In x Al1-x N films were deposited on Si(100) substrate using metal-organic molecular beam epitaxy. We investigated the effect of the trimethylindium/trimethylaluminum (TMIn/TMAl) flow ratios on the structural, morphological, and optical properties of In x Al1-x N films. Surface morphologies and microstructure of the In x Al1-x N films were measured by atomic force microscopy, scanning electron microscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. Optical properties of all films were evaluated using an ultraviolet/visible/infrared (UV/Vis/IR) reflection spectrophotometer. XRD and TEM results indicated that In x Al1-x N films were preferentially oriented in the c-axis direction. Besides, the growth rates of In x Al1-x N films were measured at around 0.6 µm/h in average. Reflection spectrum shows that the optical absorption of the In x Al1-x N films redshifts with an increase in the In composition.

Defects in semipolar (1122) ZnO grown on (112) LaAlO3/(La,Sr)(Al,Ta)O3 substrate by pulsed laser deposition.

The microstructure of semipolar [Formula: see text] ZnO deposited on (112) LaAlO3/(La,Sr)(Al,Ta)O3 was investigated by transmission electron microscopy. The ZnO shows an in-plane epitaxial relationship of [Formula: see text] with oxygen-face sense polarity. The misfit strain along [Formula: see text] and [Formula: see text] is relieved through the formation of misfit dislocations with the Burgers vectors [Formula: see text] and [Formula: see text], respectively. The line defects in the semipolar ZnO are predominantly perfect dislocations, and the dislocation density decreases with increasing ZnO thickness as a result of dislocation reactions. Planar defects were observed to lie in the M-plane and extend along 〈0001〉, whereas basal stacking faults were rarely found.

Morphology and optical properties of single- and multi-layer InAs quantum dots.

An understanding of the structural and optical properties of quantum dots (QDs) is critical for their use in optical communication devices. In this study, single- and multi-layer self-organized InAs QDs grown on (001) GaAs substrates by molecular beam epitaxy (MBE) were investigated. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images show that the lateral size of multi-layer InAs QDs are larger and flatter than single-layer InAs QDs, which are oval-shaped. The change in shape and size may be attributed to the presence of InGaAs spacer layers in multi-layer InAs QDs. Reciprocal spacer mapping and fast Fourier transformation images clearly show that InGaAs spacer layers present in the multi-layer InAs QDs structures help to release the strain originally existing in the QDs. In addition, the photoluminescence peak of the multi-layer InAs QDs is broader than QD in the single-layer one, which implies that the multi-layer InAs QDs size variation is more random than the single-layer one and this corresponds with the HAADF-STEM images. These results prove that spacer layers release strain influencing the morphology and optical properties of the QDs.

Chemical polishing method of GaAs specimens for transmission electron microscopy.

A practical method for transmission electron microscopy specimen preparation of GaAs-based materials with quantum dot structures is presented to show that high-quality image observations in high-resolution transmission electron microscopy (HRTEM) can be effectively obtained. Specimens were prepared in plan-view and cross-section using ion milling, followed by two-steps chemical fine polishing with an ammonia solution (NH(4)OH) and a dilute H(2)SO(4) solution. Measurements of electron energy loss spectroscopy (EELS) and atomic force microscopy (AFM) proved that clean and flat specimens can be obtained without chemical residues. HRTEM images show that the amorphous regions of carbon and GaAs can be significantly reduced to enhance the contrast of lattice images of GaAs-based quantum structure.

Analysis of InAsN quantum dots by transmission electron microscopy and photoluminescence.

Quantum dots (QDs) have great potential in optical fiber communication applications were widely recognized. The structure of molecular beam epitaxy (MBE) grew InAsN QDs were investigated by transmission electron microscopy (TEM) and measured their optical properties by photoluminescence (PL). TEM images show that the InAsN QDs are irregular or oval shaped. Some of the InAsN QDs are observed to have defects, such as dislocations at or near the surface in contrast to InAs QDs, which appear to be defect free. PL results for InAsN QDs showed a red-shifted emission peak. In addition, the InAsN emission peak is broader than InAs QDs, which supports the TEM observation that the size distribution of the InAsN QDs is more random than InAs QDs. The results show that the addition of nitrogen to InAs QDs leads to a decrease in the average size of the QDs, bring changes in the QD's shape, compositional distribution, and optical properties.

[Prokaryotic expression and characterization of the Rv2994 gene from Mycobacterium tuberculosis].

OBJECTIVE: To construct a prokaryotic expression vector bearing Rv2994 gene from Mycobacterium tuberculosis and provide materials for investigating the function of the gene. METHODS: The Rv2994 gene was amplified by Polymerase Chain Reaction from Mycobacterium tuberculosis H37Rv strain and cloned into prokaryotic expression vector pGEX-1lamdaXT. The recombinant plasmid pGEX-2994 was sequenced and transformed into E. coli JM109 to be induced with IPTG and expressed the 73kDa fusion protein GST-Rv2994. It's antigenicity was confirmed by Western blotting. The expression product was purified and immunized the new Zealand rabbits. RESULTS: The Rv2994 gene was amplified accurately from the genome DNA of H37Rv. A recombinant fused expression vector pGEX-Rv2994 was constructed and GST-Rv2994 protein was purifiel to immunize New Zealand rabbit. CONCLUSION: The prokaryotic expression vector pGEX-2994 was constructed, and the 73kDa fusion protein GST-Rv2994 was expressed and purified successfully. It provided the basis for the further study of the Rv2994 gene.

[Study on the gene mutation of quinolone-resistant Mycobacterium tuberculosis isolated from Sichuan Province].

OBJECTIVE: To investigate the molecular mechanism of quinolone-resistance of M. tuberculosis and characterize the gene mutation in Sichuan Province. METHODS: Susceptibility of the clinical isolates to quinolones (ofloxacin, ciprofloxacin and sparfloxacin) was tested by the absolute concentration method. GyrA gene quinolone reasistance-determining region (QRDR) mutations M. tuberculosis were detected with PCR-SSCP and DNA sequencing. RESULTS: Of 68 clinical isolates of M. tuberculosis, 25 high-resistant, 11 low-resistant and 10 sensitive isolates were noted to have abnormal gyrA SSCP profile and different gyrA sequences from the standard strain H37Rv, and 14 sensitive and 8 low-resistant isolates were found with no mutation of gyrA gene. DNA sequencing unveiled Ser-->Thr mutation at codon 95, Asp-->Gly at codon 94, Ala-->Val at codon 90, and Ala-->Val at codon 83. CONCLUSION: This study confirmed the strong correlation between the quinolone-resistance and the mutation of gyrA gene, which might be a major molecular mechanism of quinolone-resistance in M. tuberculosis. The types of mutations exhibit no difference between Sichuan Province and other areas in China.