Reductant-dependent DNA-templated silver nanoparticle formation kinetics.

DNA molecules have been demonstrated to be good templates for producing silver nanoparticles (AgNPs), with the advantages of well-controlled sizes, shapes, and properties. Revealing the formation kinetics of DNA-templated AgNPs is crucial for their efficient synthesis. Herein, using magnetic tweezers, we studied the reduction kinetics of the Ag+-DNA structure and the subsequent nucleation kinetics by adding NaBH4, L-ascorbic acid, and sodium citrate solutions. At [Ag+] = 0.01 mM, the addition of NaBH4 solution with the same concentration resulted in the restoration of DNA. In contrast, by increasing the [NaBH4]/[Ag+] ratio (r) to 10 and 100, the DNA extension initially decreased rapidly and then increased, indicating nucleation-dissolution kinetics. With AgNO3 solutions of higher concentrations (0.1 mM and 1 mM), direct particle nucleation and growth kinetics were observed by adding a tenfold (r = 10) or a hundredfold (r = 100) amount of NaBH4, which were evidenced by a significant reduction in DNA extension. The reductant dependence of the kinetics was further investigated. Addition of L-ascorbic acid to the DNA-Ag+ solution yielded an increase-decrease kinetics that was different from that caused by NaBH4, suggesting that nucleation was not initially favored due to the lack of sufficient Ag atoms; while sodium citrate showed a weak nucleation-promoting ability to form AgNPs. We discussed the findings within the framework of classical nucleation theory, in which the supersaturation of the Ag atom is strongly influenced by multiple factors (including the reducing ability of the reductant), resulting in different kinetics.

A Lox/CHOP-10 crosstalk governs osteogenic and adipogenic cell fate by MSCs.

Accelerated marrow adipogenesis has been associated with ageing and osteoporosis and is thought to be because of an imbalance between adipogenic and osteogenic differentiation of mesenchymal stem cell (MSCs). We have previously found that lysyl oxidase (Lox) inhibition disrupts BMP4-induced adipocytic lineage commitment and differentiation of MSCs. In this study, we found that lox inhibition dramatically up-regulates BMP4-induced expression of CCAAT/enhancer binding protein (C/EBP) homologous protein 10 (CHOP-10), which then promotes BMP4-induced osteogenesis of MSCs both in vitro and in vivo. Specifically, Lox inhibition or CHOP-10 up-regulation activated Wnt/ß-catenin signalling to enhance BMP4-induced osteogenesis, with pro-adipogenic p38 MAPK and Smad signalling suppressed. Together, we demonstrate that Lox/CHOP-10 crosstalk regulates BMP4-induced osteogenic and adipogenic fate determination of MSCs, presenting a promising therapeutic target for osteoporosis and other bone diseases.

Two-stage DNA compaction induced by silver ions suggests a cooperative binding mechanism.

The interaction between silver ions and DNA plays an important role in the therapeutic use of silver ions and in related technologies such as DNA sensors. However, the underlying mechanism has not been fully understood. In this study, the dynamics of Ag+-DNA interaction at a single-molecule level was studied using magnetic tweezers. AgNO3 solutions with concentrations ranging from 1 µM to 20 µM led to a 1.4-1.8 µm decrease in length of a single λ-DNA molecule, indicating that Ag+ has a strong binding with DNA, causing the DNA conformational change. The compaction process comprises one linear declining stage and another sigmoid-shaped stage, which can be attributed to the interaction mechanism. Considering the cooperative effect, the sigmoid trend was well explained using a phenomenological model. By contrast, addition of silver nanoparticle solution induced no detectable transition of DNA. The dependence of the interaction on ionic strength and DNA concentration was examined via morphology characterization and particle size distribution measurement. The size of the Ag+-DNA complex decreased with an increase in Ag+ ionic strength ranging from 1 µM to 1 mM. Morphology characterization confirmed that silver ions induced DNA to adopt a compacted globular conformation. At a fixed [AgNO3]:[DNA base pairs] ratio, increasing DNA concentration led to increased sizes of the complexes. Intermolecular interaction is believed to affect the Ag+-DNA complex formation to a large extent.

RhoGDIß Inhibits Bone Morphogenetic Protein 4 (BMP4)-induced Adipocyte Lineage Commitment and Favors Smooth Muscle-like Cell Differentiation.

The integration of signals involved in deciding the fate of mesenchymal stem cells is largely unknown. We used proteomics profiling to identify RhoGDIß, an inhibitor of the small G-protein Rho family, as a component that regulates commitment of C3H10T1/2 mesenchymal stem cells to the adipocyte or smooth muscle cell lineage in response to bone morphogenetic protein 4 (BMP4). RhoGDIß is notably down-regulated during BMP4-induced adipocytic lineage commitment of C3H10T1/2 mesenchymal stem cells, and this involves the cytoskeleton-associated protein lysyl oxidase. Excess RhoGDIß completely prevents BMP4-induced commitment to the adipocyte lineage and simultaneously stimulates smooth muscle cell commitment by suppressing the activation of Rac1. Overexpression of RhoGDIß induces stress fibers of F-actin by a process involving phosphomyosin light chain, indicating that cytoskeletal tension regulated by RhoGDIß contributes to determining adipocyte versus myocyte commitment. Furthermore, the overexpression of RacV12 (constitutively active form of Rac1) totally rescues the inhibition of adipocyte commitment by RhoGDIß, simultaneously preventing formation of the smooth muscle-like phenotype and disrupting the stress fibers in cells overexpressing RhoGDIß. Collectively, these results indicate that RhoGDIß functions as a novel BMP4 signaling target that regulates adipogenesis and myogensis.

Delivery of Constitutively Active Mutant MKK6(E) With TAT-OSBP Induces Apoptosis in Human Ovarian Carcinoma HO8910 Cells.

Biologically active peptides and proteins are novel agents that show promise in the development of anticancer drugs. Their relatively low cell permeability and poor tumor selectivity, however, impede their widespread applicability. In this study, we evaluated the tumor selectivity, cellular internalization, and biological activity of a cell-permeable ovarian cancer cell-specific therapeutic protein consisting of TAT-OSBP and constitutively active MKK6(E), an upstream kinase of the p38 signaling pathway that mediates cellular apoptosis. OSBP, a 7-amino-acid peptide with high affinity for human ovarian cancer HO8910 cells, was conjugated to the cell-penetrating peptide (TAT) to form a tumor-selective peptide (TAT-OSBP), which was further conjugated with EGFP or MKK6(E). Flow cytometry and fluorescent microscopy were performed to evaluate the tumor-targeted penetration of TAT-OSBP-EGFP. The inhibitory effects of TAT-OSBP-MKK6(E) were determined by cell proliferation and apoptosis assays. The internalization efficiency of TAT-OSBP-EGFP was significantly higher than that of TAT-EGFP. TAT-OSBP-EGFP selectively penetrated HO8910 cells. TAT-OSBP-MKK6(E) fusion protein inhibited cancer cell growth to varying degrees, with the highest level of inhibition in HO8910 cells. Moreover, TAT-OSBP-MKK6(E) significantly induced apoptosis of HO8910 cells. However, there was no significant difference in apoptosis in the normal ovarian epithelial cells treated with either TAT-OSBP-MKK6(E) or TAT-MKK6(E). Our results demonstrate that TAT-OSBP-MKK6(E) is a novel artificially designed molecule, which induces apoptosis and selectively targets human ovarian carcinoma HO8910 cells. Our study provides novel insights that may aid in the development of a new generation of anticancer drugs.

[Effect and mechanism of gene therapy of lentivirus mediated RhoA shRNA on ovarian cancer xenograft in vivo].

OBJECTIVE: To investigate treatment effects of lentivirus mediated RhoA short hairpin RNA (shRNA) on xenograft tumor of ovarian cancer in nude mice in vivo and the underlying mechanism. METHODS: Human ovarian cancer cell line HO8910 were inoculated to establish subcutaneous xenograft model of human ovarian cancer. Tumor-bearing nude mice were assigned randomizely to three groups: Lenti-RhoA-sh group, Lenti- negative control (NC) group and phosphate buffered saline (PBS) group.lentivirus mediated RhoA shRNA, negative control lentivirus and PBS were respectively injected in the three groups. Effects of treatment were observed by tumor growth curve, tumor volume, tumor weight, and tumor inhibition rate. Xenograft tissues and liver, spleen, lung, and renal tissues were examined by hematoxylin and eosin (HE) staining or were detected by streptavidin-perosidase(SP)immunochemical method. The changes of RhoA gene expression in xenograft tissues after lentivirus mediated RhoA shRNA treated were also detected by real-time qPCR, immunochemistry and Western blot assay. Cell apoptosis in xenograft tissues were examined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method and apoptotic index (AI) were counted. RESULTS: Compared with Lenti-NC group and PBS group, the growth speed of xenograft in Lenti-RhoA-sh group delayed significantly after injection 9 days (P < 0.01) . Tumor volume (338 ± 114) mm(3) decreased significantly in the Lenti-RhoA-sh group when compared with those in Lenti-NC group (1190 ± 332) mm(3) and PBS group (1101 ± 396) mm(3) (P < 0.01) . Tumor weight (0.23 ± 0.11) g decreased significantly in the Lenti-RhoA-sh group when compared with Lenti-NC group (0.79 ± 0.19) g and PBS group (0.74 ± 0.17) g (P < 0.01) . Real-time qPCR result shown that the expression of RhoA mRNA (0.30 ± 0.05) decreased significantly in the Lenti-RhoA-sh group compared with Lenti-NC group (0.95 ± 0.06) and PBS group(1.00 ± 0.11; P < 0.01) .Western blot result showed that the expression level of RhoA protein decreased significantly in the Lenti-RhoA-sh group (0.14 ± 0.06) compared with those in Lenti-NC group(0.78 ± 0.14) and PBS group (0.75 ± 0.13;P < 0.01). TUNEL staining displayed that AI significantly increased in the Lenti-RhoA-sh group (20.9 ± 3.4) % compared with those in Lenti-NC group (5.2 ± 2.0) % and PBS group (6.0 ± 2.1) % (P < 0.01). CONCLUSION: Lentivirus mediated RhoA shRNA may be effectively down-regulate of the expression of RhoA, inhibit the growth of subcutaneous xenograft tumor of ovarian cancer in nude mice by increasing the cell apoptosis.

Burnout, depression, anxiety and insomnia among medical staff during the COVID-19 epidemic in Shanghai.

Background: Coronavirus disease 2019 (COVID-19) has progressively impacted our daily lives, resulting in unexpected physical and mental stress on medical staff. This study is designed to investigate the levels of and risk factors for burnout, depression, anxiety, and insomnia among medical staff during the COVID-19 epidemic breakout in Shanghai, China. Methods: This cross-sectional survey was conducted from May 1 to May 31, 2022, among medical staff who were on the frontline during the epidemic breakout in Shanghai from different institutions. The MBI-HSS was used to assess burnout, PHQ-9, GAD-7 and ISI were used to evaluate mental status and insomnia. Results: A total of 543 valid questionnaires were collected. The depersonalization, depression, anxiety, and insomnia scores of medical staff were significantly higher during the pandemic in Shanghai compared with norms, while lack of personal achievement scores were decreased. Working time, work unit, work environment and age are important influencers of burnout, depression and anxiety of medical staff. Long working hours are the most likely causes of burnout and emotional disorders. Medical staff in primary hospitals were most likely to suffer from burnout and emotional disorders, while medical staff in tertiary hospitals had a reduced sense of personal achievement. Young medical staff are prone to negative emotions such as depression and anxiety, while older medical staff have a lower sense of personal accomplishment. Medical staff who were not in the shelter hospitals or designated hospitals were more likely to have problems of emotional exhaustion, depersonalization and anxiety than those who were in the shelter hospitals or designated hospitals. Contracting COVID-19 had no effect on medical staff. Emotional exhaustion and depersonalization were positively correlated with anxiety, depression, and sleep disorders while personal achievement was negatively correlated with these factors. Conclusion: Medical staff in Shanghai had high burnout, depression, anxiety and insomnia levels during the epidemic outbreak in Shanghai. During the COVID-19, medical staff may suffer different psychological problems which should be concerned. Care and supports about burnout, mental health and insomnia need to be taken to promote the mental health of medical staff according to different characteristics of medical staff.

Separation of false-positive microplastics and analysis of microplastics via a two-phase system combined with confocal Raman spectroscopy.

In the field of microplastics research, more accurate standardised methods and analytical techniques still need to be explored. In this study, a new method for the microplastics quantitatively and qualitatively analysis by two-phase (ethyl acetate-water) system combined with confocal Raman spectroscopy was developed. Microplastics can be separated from false-positive microplastics in beach sand and marine sediment, attributing to the hydrophobic-lipophilic interaction (HLI) of the two-phase system. Results show that the recovery rates of complex environment microplastics (polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyamide 66 (PA 66), polycarbonate (PC) and polyethylene (PE)) are higher than 92.98%. Moreover, the new technique can also be used to detect hydrophobic and lipophilic antibiotics, such as sulfamethoxazole (SMX), erythromycin (EM), madimycin (MD), and josamycin (JOS), which adsorbed on microplastics and are extracted based on the dissolving-precipitating mechanism. This innovative research strategy provides a new scope for further detection of marine environment microplastics and toxic compounds adsorbed on its surface.

Expressions of thermostable bacterial cellulases in tobacco plant.

An economical method for the conversion of lignocellulosic biomass is to use plants as bioreactors for cellulases production. Two bacterial thermostable cellulases (E2 and E3) and a E3-E2 fusion form were expressed in tobacco, driven by a double 35S promoter and 5' TEV-UTL. The enzymes were targeted to the apoplast and cytosol via 5' signal peptides and 3' retention signal peptides, respectively, and all showed functional activities. All transgenic plants exhibited normal growth compared to wild type. Transgenic plants that expressed apoplast-localized E2 had the highest average activity, about 1.5 and 3 times higher than those expressed ER-localized and cytosolic E2, respectively. Effect of subcellular compartment localization was due primarily to post-transcriptional modification, since mRNA abundances were similar despite the range of cellulase activities obtained. The recombinant cellulases exhibited good thermostability below 65 °C. After storing for 3 days at -20 and 28 °C, the enzymes lost nearly 20 and 80% of activity, respectively. The results suggested a potential application for heterologous expression of cellulases in plant for biomass conversion.

Functional analysis of gene expression profiling-based prediction in bladder cancer.

The present study aimed to analyze the modification of gene expression in bladder cancer (BC) by identifying significant differentially expressed genes (DEGs) and functionally assess them using bioinformatics analysis. To achieve this, two microarray datasets, GSE24152 (which included 10 fresh tumor tissue samples from urothelial bladder carcinoma patients and 7 benign mucosa samples from the bladder), and GSE42089 (which included 10 tissues samples from urothelial cell carcinoma patients and 8 tissues samples from the normal bladder), were downloaded from the Gene Expression Omnibus database for further analysis. Differentially expressed genes (DEGs) were screened between benign the mucosa and control groups in GSE24152 and GSE42089 datasets. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis were performed on overlapping DEGs identified in GSE24152 and GSE42089. Protein-protein interaction (PPI) networks and sub-networks were then constructed to identify key genes and main pathways. GO terms analysis was also performed for the selected clusters. In total, 1,325 DEGs in GSE24152 and 647 DEGs in GSE42089 were screened, in which 619 common DEGs were identified. The DEGs were mainly enriched in pathways and GO terms associated with mitotic and chromosome assembly, including nucleosome assembly, spindle checkpoint and DNA replication. In the interaction network, progesterone receptor (PGR), MAF bZIP transcription factor G (MAFG), cell division cycle 6 (CDC6) and members of the minichromosome maintenance family (MCMs) were identified as key genes. Histones were also considered to be significant factors in BC. Nucleosome assembly and sequence-specific DNA binding were the most significant clustered GO terms. In conclusion, the DEGs, including PGR, MAFG, CDC6 and MCMs, and those encoding the core histone family were closely associated with the development of BC via pathways associated with mitotic and chromosome assembly.

A systems pharmacology-oriented discovery of a new therapeutic use of the TCM formula Liuweiwuling for liver failure.

Multiple components of traditional Chinese medicine (TCM) formulae determine their treatment targets for multiple diseases as opposed to a particular disease. However, discovering the unexplored therapeutic potential of a TCM formula remains challenging and costly. Inspired by the drug repositioning methodology, we propose an integrated strategy to feasibly identify new therapeutic uses for a formula composed of six herbs, Liuweiwuling. First, we developed a comprehensive systems approach to enrich drug compound-liver disease networks to analyse the major predicted diseases of Liuweiwuling and discover its potential effect on liver failure. The underlying mechanisms were subsequently predicted to mainly attribute to a blockade of hepatocyte apoptosis via a synergistic combination of multiple effects. Next, a classical pharmacology experiment was designed to validate the effects of Liuweiwuling on different models of fulminant liver failure induced by D-galactosamine/lipopolysaccharide (GalN/LPS) or thioacetamide (TAA). The results indicated that pretreatment with Liuweiwuling restored liver function and reduced lethality induced by GalN/LPS or TAA in a dose-dependent manner, which was partially attributable to the abrogation of hepatocyte apoptosis by multiple synergistic effects. In summary, the integrated strategy discussed in this paper may provide a new approach for the more efficient discovery of new therapeutic uses for TCM formulae.

miR-27 impairs the adipogenic lineage commitment via targeting lysyl oxidase.

OBJECTIVE: The recruitment and commitment of mesenchymal stem cells and their terminal differentiation into adipocytes are the main pathways for increasing adipocyte cell numbers during obesity. Our previous studies have shown that lysyl oxidase (Lox) is upregulated and functions as an essential factor during bone morphogenetic protein 4 (BMP4) -induced C3H10T1/2 cell adipocytic lineage commitment. However, the mechanism of Lox regulation during adipogenic lineage commitment has remained largely unestablished. METHODS: Samples of adipose tissue from humans with different BMI and C57BL/6 mice with a high-fat diet were used to compare microRNA-27 (miR-27) expression level associated with obesity. Taqman assays were used for miR-27 expression detection and Oil Red O staining for adipogenesis analysis. RESULTS: A negative correlation was identified between Lox expression level and miR-27 expression in both BMP4-treated C3H10T1/2 cells and human subcutaneous adipose tissues. A Lox 3' UTR luciferase reporter assay showed that miR-27 directly targeted Lox. Furthermore, overexpression of miR-27 impaired BMP4-induced upregulation of Lox and adipocytic commitment, which could be rescued by overexpression of mature Lox. Conversely, miR-27 inhibition by specific inhibitors increased Lox expression and adipocytic commitment. CONCLUSIONS: Taken together, these results suggest a novel role for miR-27 in repressing adipogenic lineage commitment by targeting Lox.

[Effects of acupuncture combined with medicine on expression of matrix metalloproteinase-2 in the rat of endometriosis].

OBJECTIVE: To probe into an effective method for treatment of endometriosis (EMs) and the mechanism. METHODS: Rat EMs model was established and they were randomly divided into a model group, an acup-moxibustion group, a TCM group, an acupuncture and medicine group, with a control group set. The acup-moxibustion group were treated with electroacupuncture at "Xuehai (SP 10)", "Sanyinjiao (SP 6)" and moxibustion at "Guanyuan (CV 4)"; the TCM group were treated with stomach perfusion of modified Mojie Tablet in normal saline; the acupuncture and medicine group were treated with the above two methods; both the control group and the model group were bound and treated with stomach perfusion of saline. After treatment of 35 days, the greatest diameter of the ectopic tissue was measured in the rats, pathological observation of the ectopic tissue was made and matrix metalloproteinase-2 (MMP-2) expression in the ectopic tissue was determined. RESULTS: The greatest diameter of ectopic tissue and MMP-2 expression in the ectopic tissue in the acupuncture and medicine group were significantly lower than those in the model group, the acup-moxibustion group and the TCM group (P < 0.05); and the ectopic endometrium trended to atrophy, and with necrosis of some epithelial cells. CONCLUSION: Combination of acupuncture with medicine has a better therapeutic effect on endometriosis and down-regulates the abnormal increase of MMP-2 level to inhibit the invasion of ectopic tissue to extracellular matrix, so as to reduce the ectopic tissue, hence cure of endometriosis.