Contrast-enhanced magnetic resonance angiography for monitoring an embolized renal artery aneurysm: A case report and literature review.

This case report describes a 69-year-old male patient with a renal artery aneurysm that was followed up with contrast-enhanced magnetic resonance angiography at 8 months after coil embolization treatment. Due to the disappearance of residual lumen with few metal artifacts, the therapeutic effect was satisfactory. At present, the indications for the treatment of renal artery aneurysms are still controversial and there are very few reports of postembolization images of renal artery aneurysms, with no criteria for reintervention and few reports for monitoring the embolized aneurysms. Further reports and research are still needed for the treatment of this rare disease.

Myoglobin mutant with enhanced nitrite reductase activity regulates intracellular oxidative stress in human breast cancer cells.

Heme proteins play vital roles in regulating the reactive oxygen/nitrogen species (ROS/RNS) levels in cells. In this study, we overexpressed human wild-type (WT) myoglobin (Mb) and its double mutant, F43H/H64A Mb with enhanced nitrite reductase (NIR) activity, in the typical representative triple-negative breast cancer cell, MDA-MB-231 cells. The results showed that the overexpression of F43H/H64A Mb increased the level of nitric oxide (NO) and the degree of oxidative stress, and then activated Akt/MAPK mediated apoptotic cascade, whereas WT Mb showed the opposite effect. This study indicates that Mb plays an important role in maintaining the balance of the cellular redox system and could thus be a valuable target for cancer therapy.

Regulating Effect of Cytochrome b5 Overexpression on Human Breast Cancer Cells.

Imbalance in the cellular redox system is thought to be associated with the induction and progression of breast cancers, and heme proteins may regulate the redox balance. Cytochrome b5 (Cyt b5) is a small mitochondrial heme protein. Its function and regulating mechanism in breast cancer remain unknown. In this study, we elucidated the level of endogenous oxidative stress in breast cancer cells, MCF-7 cells (hormone receptor-positive cells) and MDA-MB-231 cells (triple-negative cells), and investigated the difference in Cyt b5 content. Based on the low content of Cyt b5 in MDA-MB-231 cells, the overexpression of Cyt b5 was found to regulate the oxidative stress and apoptosis cascades, including ERK1/2 and Akt signaling pathways. The overexpressed Cyt b5 MDA-MB-231 cells were shown to exhibit decreased oxidative stress, less phosphorylation of ERK1/2 and Akt, and less cleavage of caspases 3 and 9 upon treatment with H2O2, as compared to those of normal MDA-MB-231 cells. Moreover, the overexpressed Cyt b5 most likely functioned by interacting with its protein partner, Cyt c, as suggested by co-immunoprecipitation studies. These results indicated that Cyt b5 has different effects on breast cancer cells of different phenotypes, which provides useful information for understanding the multiple roles of Cyt b5 and provides clues for clinical treatment.

Improving the cell-membrane-penetrating activity of globins by introducing positive charges on protein surface: A case study of sperm whale myoglobin.

Globins are heme proteins such as hemoglobin (Hb), myoglobin (Mb) and neuroglobin (Ngb), playing important roles in biological system. In addition to normal functions, zebrafish Ngb was able to penetrate cell membranes, whereas less was known for other globin members. In this study, to improve the cell-membrane-penetrating activity of globins, we used sperm whale Mb as a model protein and constructed a quadruple mutant of G5K/Q8K/A19K/V21K Mb (termed 4K Mb), by introduction of four positive charges on the protein surface, which was designed according to the amino acid alignment with that of zebrafish Ngb. Spectroscopic and crystallographic studies showed that the four positively charged Lys residues did not affect the protein structure. Cell-membrane-penetrating essay further showed that 4K Mb exhibited enhanced activity compared to that of native Mb. This study provides valuable information for the effect of distribution of charged residues on the protein structure and the cell-membrane-penetrating activity of globins. Therefore, it will guide the design of protein-based biomaterials for biological applications.

A facile gelator based on phenylalanine derivative is capable of forming fluorescent Zn-metallohydrogel, detecting Zn2+ in aqueous solutions and imaging Zn2+ in living cells.

Supramolecular hydrogels are attracting soft materials with potential applications. In this study, we synthesized a facile gelator (named 2-QF) based on phenylalanine derivative with a Quinoline group. 2-QF can assemble to form hydrogels at room temperature in different colors under low pH values. Moreover, 2-QF was triggered to form a yellow metallohydrogel (2-QF-Zn) at high pH by the coordination between 2-QF and Zn2+. 2-QF-Zn metallohydrogel showed excellent multi-stimuli responsiveness, especially the reversible "on-off" luminescence switching, as induced by base/acid. In addition, at a low concentration, 2-QF can selectively and visibly identify Zn2+ through fluorescence enhancement, and can detect Zn2+ at physiological pH as a chemosensor. Remarkably, 2-QF and 2-QF-Zn exhibited an excellent biocompatibility without cell cytotoxicity, and 2-QF is able to penetrate live HeLa cells and image intracellular Zn2+ by a turn-on fluorescent response, which makes it a potential candidate for biomedical applications.

Efficient biodegradation of malachite green by an artificial enzyme designed in myoglobin.

Synthetic dyes such as malachite green (MG) have a wide range of applications. Meanwhile, they bring great challenges for environmental security and cause potential damages to human health. Compared with traditional approaches, enzymatic catalysis is an emerging technique for wastewater treatment. As alternatives to natural enzymes, artificial enzymes have received much attention for potential applications. In previous studies, we have rationally designed artificial enzymes based on myoglobin (Mb), such as by introducing a distal histidine (F43H mutation) and creating a channel to the heme pocket (H64A mutation). We herein show that the artificial enzyme of F43H/H64A Mb can be successfully applied for efficient biodegradation of MG under weak acid conditions. The degradation efficiency is much higher than those of natural enzymes, such as dye-decolorizing peroxidase and laccase (13-18-fold). The interaction of MG and F43H/H64A Mb was investigated by using both experimental and molecular docking studies, and the biodegradation products of MG were also revealed by UPLC-ESI-MS analysis. Based on these results, we proposed a plausible biodegradation mechanism of MG. With the high-yield of overexpression in E. coli cells, this study suggests that the artificial enzyme has potential applications in the biodegradation of MG in fisheries and textile industries.

C30 and C31 Triterpenoids and Triterpene Sugar Esters with Cytotoxic Activities from Edible Mushroom Fomitopsis pinicola (Sw. Ex Fr.) Krast.

Fomitopsis pinicola (Sw. Ex Fr.) Krast has been commonly used as a health food source and antitumor agent. To uncover bioactive key composition of F. pinicola, in our study, we investigated the chemical constituents of a methanol extract of F. pinicola and thirty-five lanostane-type tritetpenoids; 13 new compounds (1-13) and twenty-two known analogues (14-35) were isolated. Among them, compounds 1-9 were C30 lanostane triterpenoids and triterpene sugar esters, while compounds 10-13 were C31 triterpenoids and triterpene sugar esters. Their structures and absolute configurations were elucidated by extensive 1D, 2D NMR, MS, and IR spectra. Furthermore, cytotoxic activities of all isolates against five human tumor cell lines (HL-60, A549, SMMC-7721, MCF-7, and SW480) were evaluated. The results showed that compounds 12, 14, 17, 18, 22, and 23 displayed cytotoxic effects against five human tumor cell lines with IC50 values ranging from 3.92-28.51 µM. Meanwhile, compounds 9 and 35 exhibited selected inhibitory activities against HL-60, SMMC-7721, and MCF-7 with IC50 values in the range of 13.57-36.01 µM. Furthermore, the flow cytometry analysis revealed that compounds 17, 22, and 35 induced apoptosis in HL-60 cell lines. Their structure-activity relationships were preliminarily reported. These findings indicate the vital role of triterpenoids and their glycosides in explaining antitumor effects of F. pinicola and provide important evidence for further development and utilization of this fungus.

Enhancement of protein stability by an additional disulfide bond designed in human neuroglobin.

Human neuroglobin (Ngb) forms an intramolecular disulfide bond between Cys46 and Cys55, with a third Cys120 near the protein surface, which is a promising protein model for heme protein design. In order to protect the free Cys120 and to enhance the protein stability, we herein developed a strategy by designing an additional disulfide bond between Cys120 and Cys15 via A15C mutation. The design was supported by molecular modeling, and the formation of Cys15-Cys120 disulfide bond was confirmed experimentally by ESI-MS analysis. Molecular modeling, UV-Vis and CD spectroscopy showed that the additional disulfide bond caused minimal structural alterations of Ngb. Meanwhile, the disulfide bond of Cys15-Cys120 was found to enhance both Gdn·HCl-induced unfolding stability (increased by ∼0.64 M) and pH-induced unfolding stability (decreased by ∼0.69 pH unit), as compared to those of WT Ngb with a single native disulfide bond of Cys46-Cys55. Moreover, the half denaturation temperature (T m) of A15C Ngb was determined to be higher than 100 °C. In addition, the disulfide bond of Cys15-Cys120 has slight effects on protein function, such as an increase in the rate of O2 release by ∼1.4-fold. This study not only suggests a crucial role of the artificial disulfide in protein stabilization, but also lays the groundwork for further investigation of the structure and function of Ngb, as well as for the design of other functional heme proteins, based on the scaffold of A15C Ngb with an enhanced stability.

MMP-2 gene polymorphisms in type 2 diabetes mellitus diabetic retinopathy.

AIM: To study the association between polymorphisms of the MMP-2 gene and diabetic retinopathy (DR). METHODS: MMP-2 C-1306T and C-735T SNPs was genotyped by polymerase chain reaction-restrictive fragment length polymorphism (PCR-RFLP) analysis in 151 DR patients and 150 healthy individuals served as control. RESULTS: There is no significant difference between the patient and control groups in allele or genotype distributions of MMP-2 C-735T (P=0.263 and P=0.248). Also, there is no significant difference between the patient and control in allele of MMP-2 C-1306T (P=0.03). However the result has significant deviation of C/C, C/T, T/T genotypic frequencies between the patient and control groups in MMP-2 C-1306T (P=0.008). We found that subjects with the MMP-2 C-1306T genotype had an overall 2-fold increase in the risk of developing DR [adjusted odds ratio (OR)=2.446; 95% confidence interval (CI)=1.239-4.829] compared with those with the T-1306T or C-1306T genotype. Stratification analysis showed that the MMP-2 -1306C/T and -735C/T SNPs are not associated with the development of NPDR to PDR of DR in North Chinese Han population. CONCLUSION: MMP-2 C-1306T genotypes may be associated with DR development in the Chinese population. However, there is no relationship between the MMP-2 C-735T genotypes with the development of DR.

A novel three-dimensional culture system for isolation and clonal propagation of neural stem cells using a thermo-reversible gelation polymer.

In the present study, we examined the possible utility of a three-dimensional culture system using a thermo-reversible gelation polymer to isolate and expand neural stem cells (NSCs). The polymer is a synthetic biologically inert polymer and gelates at temperatures higher than the gel-sol transition point ( approximately 20 degrees C). When fetal mouse brain cells were inoculated into the gel, spherical colonies were formed ( approximately 1% in primary culture and approximately 9% in passage cultures). The spheroid-forming cells were positive for expression of the NSC markers nestin and Musashi. Under conditions facilitating spontaneous neural differentiation, the spheroid-forming cells expressed genes characteristic to astrocytes, oligodendrocytes, and neurons. The cells could be successively propagated at least to 80 poly-D-lysines over a period of 20 weeks in the gel culture with a growth rate higher than that observed in suspension culture. The spheroids formed by fetal mouse brain cells in the gel were shown to be of clonal origin. These results indicate that the spheroid culture system is a convenient and powerful tool for isolation and clonal expansion of NSCs in vitro.

Factors required during preculture of rat oocytes soon after sperm penetration for promoting their further development in a chemically defined medium.

Blastocyst formation in a chemically defined medium (mR1ECM) of rat oocytes soon after sperm penetration is less frequent than in those undergoing male pronuclear formation. This inhibition is released by preculturing the oocytes for a few hours in modified Krebs-Ringer bicarbonate solution (mKRB). The present study examined the effects of phosphate (Pi), bovine serum albumin (BSA) and osmolarity during preculture of sperm penetrated rat oocytes on their development to blastocysts in mR1ECM in vitro. These are the major factors that differ between mR1ECM and mKRB. When oocytes collected at 0730-0800 h on the day following mating and freed from cumulus cells were precultured for 5 h in mKRB or Pi-free mKRB and then cultured for 127 h in mR1ECM, about 73-74% of oocytes developed to blastocysts. In both media, replacement of BSA with polyvinylalcohol (PVA) or osmolarity of 246 mOsM reduced blastocyst formation compared with media containing BSA or with osmolarity of 304 mOsM; blastocyst formation was greatly inhibited when oocytes were precultured in media with PVA and osmolarity of 246 mOsM. On the other hand, when precultured in mR1ECM or mR1ECM with osmolarity of 304 mOsM or BSA instead of PVA, fewer oocytes developed to blastocysts than those precultured in Pi-free mKRB and mR1ECM with osmolarity of 304 mOsM and BSA. These results indicate that both BSA and osmolarity, but not Pi, are essential factors during preculture of rat oocytes soon after sperm penetration for promoting their further development to blastocysts in a chemically defined medium.