Mesenchymal stem cell exosomes inhibit nucleus pulposus cell apoptosis via the miR-125b-5p/TRAF6/NF-κB pathway axis

Intervertebral disc degeneration (IVDD) is the pathological basis of a range of degenerative spinal diseases and is the primary cause of lower back pain. Mesenchymal stem cell (MSC) transplantation inhibits IVDD progression. However, the specific mechanisms that underlie these effects remain unclear. In this study, candidate microRNAs (miRNAs) are screened using bioinformatics and high-throughput sequencing. TNF-α is used to induce nucleus pulposus cell (NPC) degeneration. MSC-derived exosomes (MSC-exosomes) are obtained using high-speed centrifugation and identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blot analysis. Cell viability is determined by CCK-8 assay. Flow cytometry and TUNEL assays are used to detect cell apoptosis. The expression levels of miR-125b-5p are detected by RT-qPCR, and a dual-luciferase gene reporter assay confirms the downstream target genes of miR-125b-5p. Protein expression is determined by western blot analysis. Rat models are used to validate the function of miR-125b-5p in MSC-exosomes. The results show that miR-125b-5p is expressed at low levels in degenerated disc tissues compared with that in normal disc tissues; however, it is highly expressed in MSC-exosomes. Furthermore, MSC-exosomes are efficiently taken up by NPCs while miR-125b-5p is delivered into NPCs; thus, MSC-exosomes act as inhibitors of apoptosis in NPCs. Overexpression of miR-125b-5p downregulates TRAF6 expression and inhibits NF-κB activation. However, TRAF6 overexpression reverses these effects of miR-125b-5p. We demonstrate that MSC-exosomes attenuate IVDD in vivo by delivering miR-125b-5p. MSC-exosomes can deliver miR-125b-5p to target TRAF6, inhibit NF-κB activation, and attenuate the progression of IVDD.

ETS2 overexpression ameliorates cartilage injury in osteoarthritis by the ETS2/miR-155/STAT1/DNMT1 feedback loop pathway

Osteoarthritis (OA) is the most common irreversible chronic joint dysfunction disease, which is pathologically characterized by disturbance of articular cartilage homeostasis leading to subsequent inflammatory response and cartilage extracellular matrix (ECM) degradation. Increasing evidence has demonstrated the dysregulation of transcription factors play crucial roles in the occurrence and development of osteoarthritis (OA), but the potential functions and mechanism of most transcription factors in OA has not been completely illuminated. In this study, we identified that transcription factor V-ets erythroblastosis virus E26 oncogene homolog 2 (ETS2) was significantly down-regulated in OA cartilage and IL-1β-induced OA chondrocytes. Functional experiments in vitro demonstrated that the overexpressed ETS2 strikingly enhanced proliferation, outstandingly suppressed apoptosis, and dramatically reduced inflammation and ECM degradation in IL-1β-induced OA chondrocytes, whereas the knockdown of ETS2 led to the opposite effects. Further in vivo studies have shown that up-regulated ETS2 dramatically ameliorates cartilage injury in DMM-induced OA mice. Mechanical studies have disclosed that DNMT1-mediated downregulation of ETS2 dramatically promotes STAT1 by inhibiting miR-155 transcription, and increased STAT1 initiates a feedback loop that may enhance DNMT1-mediated hypermethylation of ETS2 to inhibit ETS2 expression, thus forming a DNMT1/ETS2/miR-155/STAT1 feedback loop that inhibits MAPK signaling pathways and aggravates OA cartilage injury. In all, our results revealed that overexpression of ETS2 markedly ameliorated OA cartilage injury through the ETS2/miR-155/STAT1/DNMT1 feedback loop, providing a new perspective on the pathogenesis and therapeutic strategies for OA.

ACSM5 inhibits ligamentum flavum hypertrophy by regulating lipid accumulation mediated by FABP4/PPAR signaling pathway

BACKGROUND

Ligamentum flavum (LF) hypertrophy is the main cause of lumbar spinal canal stenosis (LSCS). Previous studies have shown that LF hypertrophy tissue exhibits abnormal lipid accumulation, but the regulatory mechanism remains unclear. The objective of this study was to explore the function and potential mechanism of ACSM5 in LF lipid accumulation.

METHODS

To assess the ACSM5 expression levels, lipid accumulation and triglyceride (TG) level in LF hypertrophy and normal tissue, we utilized RT-qPCR, western blot, oil red O staining, and TG assay kit. The pearson correlation coefficient assay was used to analyze the correlation between ACSM5 levels and lipid accumulation or TG levels in LF hypertrophy tissue. The role of ACSM5 in free fatty acids (FFA)-induced lipid accumulation in LF cells was assessed in vitro, and the role of ACSM5 in LF hypertrophy in mice was verified in vivo. To investigate the underlying mechanisms of ACSM5 regulating lipid accumulation in LF, we conducted the mRNA sequencing, bioinformatics analysis, and rescue experiments.

RESULTS

In this study, we found that ACSM5, which was significantly down-regulated in LF tissues, correlated with lipid accumulation. In vitro cell experiments demonstrated that overexpression of ACSM5 significantly inhibited FFA-induced lipid accumulation and fibrosis in LF cells. In vivo animal experiments further confirmed that overexpression of ACSM5 inhibited LF thickening, lipid accumulation, and fibrosis. Mechanistically, ACSM5 inhibited lipid accumulation of LF cells by inhibiting FABP4-mediated PPARγ signaling pathway, thereby improving hypertrophy and fibrosis of LF.

CONCLUSIONS

our findings elucidated the important role of ACSM5 in the regulation of LF lipid accumulation and provide insight into potential therapeutic interventions for the treatment of LF hypertrophy. This study further suggested that therapeutic strategies targeting lipid deposition may be an effective potential approach to treat LF hypertrophy-induced LSCS.

Evaluation of CT angiography obstruction score and pulmonary perfusion defect score using the third-generation dual-source CT for pulmonary embolism

AIM

To investigate the application value of computed tomography (CT) angiography (CTA) obstruction score and pulmonary perfusion defect score on the third-generation dual-source CT for pulmonary embolism and the changes of the right ventricular function.

MATERIALS AND METHODS

The clinical data of 52 patients with pulmonary embolism (PE) confirmed using the third-generation dual-source dual-energy CTPA were analysed retrospectively. These patients were divided into the severe group and non-severe group according to their clinical manifestations. The results of CTPA and dual-energy pulmonary perfusion imaging (DEPI) were recorded by two radiologists for index computation. The ratio of the maximum short-axis diameter of the right ventricle (RV) to that of the left ventricle (LV) was also recorded. The correlation analysis between RV/LV and the mean values of CTA obstruction score and perfusion defect score was performed. Correlation analysis and agreement analysis were performed on the data measured by two radiologists, CTA obstruction score, and pulmonary perfusion defect score.

RESULTS

CTA obstruction score and perfusion defect score measured by the two radiologists had good correlation and agreement. CTA obstruction score, perfusion defect score, and RV/LV were significantly lower in the non-severe group than in the severe PE group. RV/LV had a significant positive correlation with CTA obstruction score and perfusion defect score (p<0.05).

CONCLUSION

The third-generation dual-source dual-energy CT plays a positive role in assessing PE severity and RV function and can provide additional information for the clinical management and treatment of PE patients.

LncRNA XIST facilitates hypertrophy of ligamentum flavum by activating VEGFA-mediated autophagy through sponging miR-302b-3p

BACKGROUND

Increasing evidences have shown that long non-coding RNAs (lncRNAs) display crucial regulatory roles in the occurrence and development of numerous diseases. However, the function and underlying mechanisms of lncRNAs in hypertrophy of ligamentum flavum (HLF) have not been report.

METHODS

The integrated analysis of lncRNAs sequencing, bioinformatics analysis and real-time quantitative PCR were used to identify the key lncRNAs involved in HLF progression. Gain- and loss-function experiments were used to explore the functions of lncRNA X inactive specific transcript (XIST) in HLF. Mechanistically, bioinformatics binding site analysis, RNA pull-down, dual-luciferase reporter assay, and rescue experiments were utilized to investigate the mechanism by which XIST acts as a molecular sponge of miR-302b-3p to regulate VEGFA-mediated autophagy.

RESULTS

We identified that XIST was outstandingly upregulated in HLF tissues and cells. Moreover, the up-regulation of XIST strongly correlated with the thinness and fibrosis degree of LF in LSCS patients. Functionally, knockdown of XIST drastically inhibited proliferation, anti-apoptosis, fibrosis and autophagy of HLF cells in vitro and suppressed hypertrophy and fibrosis of LF tissues in vivo. Intestinally, we uncovered that overexpression of XIST significantly promoted proliferation, anti-apoptosis and fibrosis ability of HLF cells by activating autophagy. Mechanistic studies illustrated that XIST directly medullated the VEGFA-mediated autophagy through sponging miR-302b-3p, thereby enhancing the development and progression of HLF.

CONCLUSION

Our findings highlighted that the XIST/miR-302b-3p/VEGFA-mediated autophagy axis is involved in development and progression of HLF. At the same time, this study will complement the blank of lncRNA expression profiles in HLF, which laid the foundation for further exploration of the relationship between lncRNAs and HLF in the future.

[Analysis of surgical strategy for pediatric papillary thyroid carcinoma with low-intermediate risk]

Objective: To explore the feasibility and rationality of lobectomy in the treatment of pediatric thyroid papillary carcinoma (PTC) with low-intermediate risk. Methods: The clinicopathological features and follow-up data of pediatric PTC with low-intermediate risk were reviewed from March 2000 to December 2018 in Cancer Hospital of Chinese Academy of Medical Sciences. The correlations between different surgical procedures and prognoses were evaluated. Propensity score matching(PSM) was used to adjust for risk factors, and the difference in prognoses between the total thyroidectomy (TT) group and the lobectomy (LT) group was compared. Results: A total of 140 patients were included in the study, including 36 males and 104 females. The age range was from 6-year-old to 18-year-old. There were 43 low-risk patients and 97 intermediate-risk patients. The median follow-up time was 87.5 months, ranging from 8 to 241 months, and 20 patients (14.3%) showed recurrence during the follow-up period. Univariate analysis showed that N1b, extrathyroidal extension, the number of lymph node metastasis>5, the ratio of lymph node metastasis≥0.19, and radioactive iodine treatment were risk factors for recurrence (all P value below 0.05), but multivariate analysis showed that only the ratio of lymph node metastasis≥0.19 (HR=8.69, 95%CI=1.08-70.21, P=0.043) was an independent risk factor for recurrence. There was no significant difference in the 5-year recurrence free survival rates between TT group and LT group before propensity score matching (82.8% vs. 86.5%, χ²=0.219, P=0.640) and after propensity score matching (89.6% vs. 90.4%, χ²=0.099, P=0.753). Conclusion: There is no significant difference in recurrence-free survival between TT group and LT group. Lobectomy is feasible for selective pediatric PTC with low-intermediate risk.

TCF7/SNAI2/miR-4306 feedback loop promotes hypertrophy of ligamentum flavum

Background

Hypertrophy of ligamentum flavum (HLF) is the mainly cause of lumbar spinal stenosis (LSS), but the precise mechanism of HLF formation has not been fully elucidated. Emerging evidence indicates that transcription factor 7 (TCF7) is the key downstream functional molecule of Wnt/β-catenin signaling, which participated in regulating multiple biological processes. However, the role and underlying mechanism of TCF7 in HLF is still unclear.

Methods

We used mRNAs sequencing analysis of human LF and subsequent confirmation with RT-qPCR, western blot and immunohistochemistry to identified the TCF7 in HLF tissues and cells. Then effect of TCF7 on HLF progression was investigated both in vitro and in vivo. Mechanically, chromatin immunoprecipitation, dual-luciferase reporter assays, and rescue experiments were used to validate the regulation of TCF7/SNAI2/miR-4306 feedback loop.

Results

Our results identified for first time that the TCF7 expression was obviously elevated in HLF tissues and cells compared with control, and also found that TCF7 expression had significant positive correlation with LF thickness and fibrosis score. Notably, TCF7 inhibition suppressed the hyper-proliferation and fibrosis phenotype of HLF cells in vitro and ameliorated progression of HLF in mice in vivo, whereas TCF7 overexpression promoted hyper-proliferation and fibrosis phenotype of HLF cells in vitro. Our data further revealed that TCF7 interacted with SNAI2 promoter to transactivated the SNAI2 expression, thereby promoting hyper-proliferation and fibrosis phenotype of HLF cells in vitro. Furthermore, miR-4036 negatively regulated by SNAI2 could negatively feedback regulate TCF7 expression by directly binding to TCF7 mRNA 3’-UTR, thus inhibiting the hyper-proliferation and fibrosis phenotype of HLF cells in vitro.

Conclusions

Our study demonstrated that TCF7 inhibition could suppress HLF formation by modulating TCF7/SNAI2/miR-4306 feedback loop, which might be considered as a novel potential therapeutic target for HLF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03677-0.

Validating and optimizing mismatch tolerance of Doppler backscattering measurements with the beam model (invited)

We use the beam model of Doppler backscattering (DBS), which was previously derived from beam tracing and the reciprocity theorem, to shed light on mismatch attenuation. This attenuation of the backscattered signal occurs when the wavevector of the probe beam's electric field is not in the plane perpendicular to the magnetic field. Correcting for this effect is important for determining the amplitude of the actual density fluctuations. Previous preliminary comparisons between the model and Mega-Ampere Spherical Tokamak (MAST) plasmas were promising. In this work, we quantitatively account for this effect on DIII-D, a conventional tokamak. We compare the predicted and measured mismatch attenuation in various DIII-D, MAST, and MAST-U plasmas, showing that the beam model is applicable in a wide variety of situations. Finally, we performed a preliminary parameter sweep and found that the mismatch tolerance can be improved by optimizing the probe beam's width and curvature at launch. This is potentially a design consideration for new DBS systems.

Immune cell infiltration and the genes associated with ligamentum flavum hypertrophy: Identification and validation

Ligamentum flavum hypertrophy (LFH) is a common cause of spinal stenosis. The aim of the current study was to identify the differentially expressed genes (DEGs) in LFH and the molecular mechanisms underlying the development of and immune responses to LFH. The gene expression omnibus (GEO) database was used to obtain the GSE113212 dataset, and the DEGs were derived from microarray data. To identify critical genes and signaling pathways, gene ontology enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network analyses were performed, followed by immune cell infiltration and Friends analyses using the retrieved datasets. The results were validated using quantitative real-time PCR. The 1530 DEGs identified comprised 971 upregulated and 559 downregulated genes. KEGG analysis revealed that DEGs were mostly enriched in the PI3K-Akt signaling pathway, while PPI network analysis identified tumor necrosis factor, interleukin (IL)-6, IL-10, epidermal growth factor receptor, and leptin as important nodes, which was validated by qPCR and IHC in human LFH tissues in vitro. A significant positive correlation was found between key LFH immune-related DEGs and several immune cell types, including T and B cells. The findings of the present study might lead to novel therapeutic targets and clinical approaches, as they provide insights into the molecular mechanisms of LFH.

Identification of Core Genes and Screening of Potential Targets in Intervertebral Disc Degeneration Using Integrated Bioinformatics Analysis

Background: Intervertebral disc degeneration (IDD), characterized by diverse pathological changes, causes low back pain (LBP). However, prophylactic and delaying treatments for IDD are limited. The aim of our study was to investigate the gene network and biomarkers of IDD and suggest potential therapeutic targets.

Methods: Differentially expressed genes (DEGs) associated with IDD were identified by analyzing the mRNA, miRNA, and lncRNA expression profiles of IDD cases from the Gene Expression Omnibus (GEO). The protein–protein interaction (PPI) network, Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis as well as miRNA–lncRNA–mRNA networks were conducted. Moreover, we obtained 71 hub genes and performed a comprehensive analysis including GO, KEGG, gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), Disease Ontology (DO), methylation analysis, receiver operating characteristic (ROC) curve analysis, immune infiltration analysis, and potential drug identification. We finally used qRT-PCR to verify 13 significant DEGs in normal and degenerative nucleus pulposus cells (NPCs).

Results: We identified 305 DEGs closely related to IDD. The GO and KEGG analyses indicated that changes in IDD are significantly associated with enrichment of the inflammatory and immune response. GSEA analysis suggested that cell activation involved in the inflammatory immune response amide biosynthetic process was the key for the development of IDD. The GSVA suggested that DNA repair, oxidative phosphorylation, peroxisome, IL-6-JAK-STAT3 signaling, and apoptosis were crucial in the development of IDD. Among the 71 hub genes, the methylation levels of 11 genes were increased in IDD. A total of twenty genes showed a high functional similarity and diagnostic value in IDD. The result of the immune cell infiltration analysis indicated that seven genes were closely related to active natural killer cells. The most relevant targeted hub genes for potential drug or molecular compounds were MET and PIK3CD. Also, qRT-PCR results showed that ARHGAP27, C15orf39, DEPDC1, DHRSX, MGAM, SLC11A1, SMC4, and LINC00887 were significantly downregulated in degenerative NPCs; H19, LINC00685, mir-185-5p, and mir-4306 were upregulated in degenerative NPCs; and the expression level of mir-663a did not change significantly in normal and degenerative NPCs.

Conclusion: Our findings may provide new insights into the functional characteristics and mechanism of IDD and aid the development of IDD therapeutics.

Bioinformatics-Led Discovery of Osteoarthritis Biomarkers and Inflammatory Infiltrates

The molecular mechanisms of osteoarthritis, the most common chronic disease, remain unexplained. This study aimed to use bioinformatic methods to identify the key biomarkers and immune infiltration in osteoarthritis. Gene expression profiles (GSE55235, GSE55457, GSE77298, and GSE82107) were selected from the Gene Expression Omnibus database. A protein-protein interaction network was created, and functional enrichment analysis and genomic enrichment analysis were performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) databases. Immune cell infiltration between osteoarthritic tissues and control tissues was analyzed using the CIBERSORT method. Identify immune patterns using the ConsensusClusterPlus package in R software using a consistent clustering approach. Molecular biological investigations were performed to discover the important genes in cartilage cells. A total of 105 differentially expressed genes were identified. Differentially expressed genes were enriched in immunological response, chemokine-mediated signaling pathway, and inflammatory response revealed by the analysis of GO and KEGG databases. Two distinct immune patterns (ClusterA and ClusterB) were identified using the ConsensusClusterPlus. Cluster A patients had significantly lower resting dendritic cells, M2 macrophages, resting mast cells, activated natural killer cells and regulatory T cells than Cluster B patients. The expression levels of TCA1, TLR7, MMP9, CXCL10, CXCL13, HLA-DRA, and ADIPOQSPP1 were significantly higher in the IL-1β-induced group than in the osteoarthritis group in an in vitro qPCR experiment. Explaining the differences in immune infiltration between osteoarthritic tissues and normal tissues will contribute to the understanding of the development of osteoarthritis.

m6A Regulator-Mediated RNA Methylation Modification Patterns Regulate the Immune Microenvironment in Osteoarthritis

Epigenetic regulation, particularly RNA n6 methyl adenosine (m6A) modification, plays an important role in the immune response. However, the regulatory role of m6A in the immune microenvironment in osteoarthritis (OA) remains unclear. Accordingly, we systematically studied RNA modification patterns mediated by 23 m6A regulators in 38 samples and discussed the characteristics of the immune microenvironment modified by m6A. Next, we constructed a novel OA m6A nomogram, an m6A-transcription factor-miRNA network, and a drug network. Healthy and OA samples showed distinct m6A regulatory factor expression patterns. YTHDF3 expression was upregulated in OA samples and positively correlated with type II helper cells and TGFb family member receptors. Furthermore, three different RNA modification patterns were mediated by 23 m6A regulatory factors; in Mode 3, the expression levels of YTHDF3, type II T helper cells, and TGFb family member receptors were upregulated. Pathways related to endoplasmic reticulum oxidative stress and mitochondrial autophagy showed a strong correlation with the regulatory factors associated with Mode 3 and 23 m6A regulatory factors. Through RT-qPCR we validated that SREBF2 and EGR1 as transcription factors of YTHDF3 and IGF2BP3 are closely associated with the development of OA, hsa-miR-340 as a miRNA for YTHDF3 and IGF2BP3 was involved in the development of OA, we also detected the protein expression levels of IGF2BP3, YTHDF3, EGR1 and SREBF2 by western blotting, and the results were consistent with PCR. Overall, the constructed nomogram can facilitate the prediction of OA risk.

Exosomes derived from PC-3 cells suppress osteoclast differentiation by downregulating miR-148a and blocking the PI3K/AKT/mTOR pathway

Prostate cancer is a leading malignancy in men that can also disrupt the bone tissue balance. Among all urological cancers, prostate cancer is associated with the highest rate of bone metastases, which can greatly reduce a patient's quality of life. In recent years, cell-derived exosomes, which can contain a wide range of biologically active molecules, have been reported as a novel method of communication among individual cells. However, the specific role that exosomes serve in this disease has not been fully elucidated. The prostate cancer cell line PC-3 were applied in the present study, where its exosomes were isolated to explore their potential effects on osteoclast differentiation. Exosomes are extracellular vesicles secreted by cells. The size of exosomes is 30-150 nm. They have double membrane structure and saucer-like morphology. They contain rich contents (including nucleic acid, protein and lipid) and participate in molecular transmission between cells. The combined results of tartrate-resistant acid phosphatase staining (to identify osteoclasts obtained from human peripheral blood mononuclear cells), reverse transcription-quantitative PCR and western blotting showed that PC-3-derived exosomes attenuated osteoclast differentiation by downregulating marker genes associated with osteoclastic maturation, including V-maf musculoaponeurotic fibrosarcoma oncogene homolog B, matrix metalloproteinase 9 and integrin β3. microRNA (miR)-148a expression was also found to be downregulated in osteoclasts by PC-3-derived exosomes. In addition, the mTOR and AKT signaling pathways were blocked after exposure to these PC-3 cell-derived exosomes. Therefore, results from the present study suggest that miR-148a mimics may be a new therapeutic approach for the prevention of prostate cancer bone metastases.

Integrative analysis of genome-wide DNA methylation and single-nucleotide polymorphism identified ACSM5 as a suppressor of lumbar ligamentum flavum hypertrophy

BACKGROUND

Hypertrophy of ligamentum flavum (HLF) is a common lumbar degeneration disease (LDD) with typical symptoms of low back pain and limb numbness owing to an abnormal pressure on spinal nerves. Previous studies revealed HLF might be caused by fibrosis, inflammatory, and other bio-pathways. However, a global analysis of HLF is needed severely.

METHODS

A genome-wide DNA methylation and single-nucleotide polymorphism analysis were performed from five LDD patients with HLF and five LDD patients without HLF. Comprehensive integrated analysis was performed using bioinformatics analysis and the validated experiments including Sanger sequencing, methylation-specific PCR, qPCR and ROC analysis. Furthermore, the function of novel genes in ligamentum flavum cells (LFCs) was detected to explore the molecular mechanism in HLF through knock down experiment, overexpression experiment, CCK8 assay, apoptosis assay, and so on.

RESULTS

We identified 69 SNP genes and 735 661 differentially methylated sites that were enriched in extracellular matrix, inflammatory, and cell proliferation. A comprehensive analysis demonstrated key genes in regulating the development of HLF including ACSM5. Furthermore, the hypermethylation of ACSM5 that was mediated by DNMT1 led to downregulation of ACSM5 expression, promoted the proliferation and fibrosis, and inhibited the apoptosis of LFCs.

CONCLUSION

This study revealed that DNMT1/ACSM5 signaling could enhance HLF properties in vitro as a potential therapeutic strategy for HLF.

Lipotoxic stress alters the membrane lipid profile of extracellular vesicles released by Huh-7 hepatocarcinoma cells

Extracellular vesicles (EVs) are well-known mediators in intercellular communication playing pivotal roles in promoting liver inflammation and fibrosis, events associated to hepatic lipotoxicity caused by saturated free fatty acid overloading. However, despite the importance of lipids in EV membrane architecture which, in turn, affects EV biophysical and biological properties, little is known about the lipid asset of EVs released under these conditions. Here, we analyzed phospholipid profile alterations of EVs released by hepatocarcinoma Huh-7 cells under increased membrane lipid saturation induced by supplementation with saturated fatty acid palmitate or Δ9 desaturase inhibition, using oleate, a nontoxic monounsaturated fatty acid, as control. As an increase of membrane lipid saturation induces endoplasmic reticulum (ER) stress, we also analyzed phospholipid rearrangements in EVs released by Huh-7 cells treated with thapsigargin, a conventional ER stress inducer. Results demonstrate that lipotoxic and/or ER stress conditions induced rearrangements not only into cell membrane phospholipids but also into the released EVs. Thus, cell membrane saturation level and/or ER stress are crucial to determine which lipids are discarded via EVs and EV lipid cargos might be useful to discriminate hepatic lipid overloading and ER stress.

KIF21B Expression in Osteosarcoma and Its Regulatory Effect on Osteosarcoma Cell Proliferation and Apoptosis Through the PI3K/AKT Pathway

Osteosarcoma (OS) is the most common malignancy that occurs mainly during childhood and adolescence; however, no clear molecular or biological mechanism has been identified. In this study, we aimed to explore new biomarkers for the early diagnosis, targeted treatment, and prognostic determination of osteosarcoma. We first used bioinformatics analysis to show that KIF21B can be used as a biomarker for the diagnosis and prognosis of osteosarcoma. We then examined the expression of KIF21B in human osteosarcoma tissues and cell lines using immunohistochemistry, western blotting, and qRT-PCR. It was found that KIF21B expression was significantly upregulated in osteosarcoma tissues and cell lines. After knocking down the expression of KIF21B in the osteosarcoma cell lines 143B and U2-OS, we used cell fluorescence counting, CCK-8 assays, flow cytometry, and TUNEL staining to examine the effects of KIF21B on osteosarcoma cell proliferation and apoptosis. The results demonstrated that knocking down KIF21B in 143B and U2-OS cells could increase cell apoptosis, inhibit cell proliferation, and reduce tumor formation in nude mice. Subsequently, we used gene chips and bioinformatics to analyze the differential gene expression caused by knocking down KIF21B. The results showed that KIF21B may regulate OS cell proliferation and apoptosis by targeting the PI3K/AKT pathway. We then examined the expression of PI3K/AKT- and apoptosis-related proteins using western blotting. KIF21B knockdown inhibited the PI3K pathway, downregulated Bcl-2, and upregulated Bax. Moreover, the use of PI3K/AKT pathway agonists reversed the regulatory effect of KIF21B on the apoptosis and proliferation of 143B and U2-OS cells. In conclusion, our results indicated that KIF21B plays a key role in osteosarcoma. Low KIF21B expression might indirectly increase the apoptosis and inhibit the proliferation of osteosarcoma cells through the PI3K/AKT pathway.

Cadmium chloride enhances cisplatin sensitivity in osteosarcoma cells by reducing FOXM1 expression

Osteosarcoma is a highly malignant disease and is associated with a poor patient prognosis and a high mortality rate. Disease prognosis significantly correlates with chemotherapeutic responses. Cadmium is a heavy metal with specific effects on bone, but its benefits for osteosarcoma treatment have not been characterized. In the present study, cadmium chloride was used to treat MG63 osteosarcoma cells, and their gene expression profiles were assessed by GeneChip technology. We found that forkhead box protein M1 (FOXM1) was downregulated by cadmium chloride, and lentiviral‑mediated silencing of FOXM1 confirmed a role for this factor in the cisplatin resistance of MG63 cells. In nude mice, cadmium chloride enhanced the sensitivity of osteosarcoma to cisplatin, an effect mediated by FOXM1. Collectively, these data indicate that cadmium chloride can alter the sensitivity of osteosarcoma cells to cisplatin through FOXM1, highlighting it as a potential therapeutic target and prognostic factor for osteosarcoma.

Prediction of staggered stacking 2D BeP semiconductor with unique anisotropic electronic properties

By comprehensive structure design and first-principles calculations, we report a novel two-dimensional (2D) BeP nanomaterial with exotic structural and properties. This BeP 2D material is formed by a couple honeycomb sheets by slab staggered stacking and strong interlayer bondings. It behaves as a natural 2D semiconductor with several notable properties: a modest bandgap (~1.34 eV), high room-temperature electron mobility (~10⁴ cm² V^-1 s^-1) and high visible-light absorption coefficient (~10⁵ cm^-1); Moreover, due to the unique stacking topology, BeP may display distinctive direction-dependent electric transport by the anisotropic polarity of electron and hole mobilities, that is, it exhibits n-type (electron mobility  >  hole mobility) along the armchair direction while acts as p -type (hole mobility  >  electron mobility) in the zigzag direction, thus promising for applications in nanoelectronics. The BeP has good dynamic and thermal stabilities and is also the lowest-energy structure of 2D space indicated by particle swarm search, implying the high feasibility of experimental synthesis.

Intrinsic phonon-mediated superconductivity in graphene-like BSi lattice

The research of new superconductors is an ongoing field for the fundamental significances and potential applications, and two-dimensional (2D) nanomaterials open a new alluring branch for exploration. Here we predict by first-principles calculations that 2D pristine graphene-like BSi monolayer is a phonon-mediated superconductor above the boiling point of liquid helium. The intrinsic covalent-metallic ground state, large density of states at Fermi energy, proper electronic organization as well as strong coupling of out-of-plane phonons and electrons endow an intermediate electron-phonon coupling of ~1.12, rendering this honeycomb sheet as a conventional superconductor with a relatively high T _c ~ 11 K. As the global minimum structure in the 2D space previously predicted, this superconducting BSi monolayer may be feasible experimentally. Our finding provides a new field of superconducting nanomaterials for study.

Rapid and sensitive detection of redspotted grouper nervous necrosis virus (RGNNV) infection by aptamer-coat protein-aptamer sandwich enzyme-linked apta-sorbent assay (ELASA)

Redspotted grouper nervous necrosis virus (RGNNV) is one of the most devastating pathogens in the aquaculture of the grouper, Epinephlus sp., worldwide. The early and rapid diagnosis of RGNNV is important for the prevention of RGNNV infection. In this study, an aptamer (A10)-based sandwich enzyme-linked apta-sorbent assay (ELASA) was developed for RGNNV diagnosis. This sandwich ELASA showed high specificity for the RGNNV coat protein (CP) and virions in virus-infected cells and tissues. At the optimized working concentration of 200 nM of aptamer, the ELASA could detect RGNNV in the lysates of as few as 4 × 10³ RGNNV-infected GB cells. Incubation for 10 min was sufficient to produce accurate results. The sandwich ELASA was most stable at incubation temperatures of 4-25°C, but could still distinguish RGNNV-infected samples from the controls at 37°C. It could detect RGNNV infection in brain lysates diluted 1/10, with results consistent with those of reverse transcription PCR, although with 10% less sensitivity. The main equipment required includes dissection tools, a water bath, Pierce™ Streptavidin Coated Plates and a microplate reader. The sandwich ELASA has great potential utility for the rapid and sensitive diagnosis of RGNNV in its early stages by fish farmers.

The effects of tourniquet use in total knee arthroplasty: a randomized, controlled trial

PURPOSE

Tourniquets are still widely used in total knee arthroplasty (TKA), although they may be associated with several adverse effects. An observer-blinded, randomized, controlled trial was performed to evaluate the effects of tourniquet use in TKA.

METHODS

Fifty participants who underwent staged bilateral TKA were recruited for this study. The first-side TKA was randomly allocated to either long-duration tourniquet use or short-duration tourniquet use followed by a 3-month washout period and crossover to the other tourniquet strategy for the opposite-side TKA. Blood loss was monitored perioperatively. The operating time, allogeneic blood transfusion rate, thigh pain, knee pain, limb swelling, clinical outcome as measured by the Likert-type Western Ontario and McMaster University (WOMAC) score, straight leg raising and knee active range of motion (ROM) were also recorded.

RESULTS

The long-duration tourniquet group exhibited reduced total blood loss [-99.1 ml, 95 % confidence interval (CI) -168.1 to -30.1, P = 0.0411] and intraoperative blood loss (-225.2 ml, 95 % CI -369.5 to -80.9, P = 0.0071) compared with the short-duration tourniquet group. However, there were greater postoperative blood loss (69.6 ml, 95 % CI 21.1 to 118.2, P = 0.0282) and hidden blood loss (52.8 ml, 95 % CI 10.5 to 95.1, P = 0.0332) in the long-duration tourniquet group. The short-duration tourniquet group showed better outcomes for thigh and knee pain, limb swelling, WOMAC score at 6-week follow-up, straight leg raising and knee ROM. Similar allogeneic blood transfusion rates were observed for both groups.

CONCLUSION

Total and intraoperative blood losses were reduced with the long-duration tourniquet use, whereas the short-duration tourniquet use would reduce postoperative and hidden blood losses without increasing the allogeneic blood transfusion rate. In addition, short-duration tourniquet use would result in faster recovery and less pain during the early rehabilitation period following TKA.

LEVEL OF EVIDENCE

I.

[Clinical analysis of secondary cervical lymph node dissection in papillary thyroid carcinoma]

Objective: To investigate the value of secondary cervical lymph node dissection in papillary thyroid carcinoma (PTC). Methods: PTC patients with recurrence re-operated in a previously dissected area at our hospital during 2000-2016 were included in this analysis. Patients were divided according to the operative interval of 6 months. The level and number of lymph node metastasis and the number of lymph node dissection were analyzed to calculate the ratio of lymph node metastasis. Results: A total of 336 PTC patients received 360 side lateral cervical lymph nodes dissection. The ratio of recurrence in unilateral lateral neck is 92.9%(312/336). The ratio of recurrence in multiple levels (more than two regions) were 47.5% (171/360). The recurrence ratio of level Ⅱ, Ⅲ, Ⅳ and Ⅴ were 55.6%(200/360), 44.2%(159/360), 59.7%(215/360) and 10.3%(37/360), respectively. Lymph node metastases were inclined to level Ⅱ (33.6%) and Ⅳ (35.8%). The mean number of lymph node dissection and metastasis in the group of operative interval ≤ 6 months was 26.56 per case and 4.37 per case, respectively. The mean number of lymph node dissection and metastasis in the group of operative interval >6 months was 16.80 per case and 3.20 per case, respectively. The number of lymph node dissection and metastasis between these two groups were significantly different (P=0.001, P<0.001). Conclusions: Lymph node metastasis of PTC patients with secondary cervical lymph node dissection are inclined to level Ⅱ and level Ⅳ. Moreover, multi-level metastasis is not rare. Level Ⅱ and level Ⅳ require more attention in the first operation. Most of the patients undergo reoperation because of residual lymph nodes from the previous treatment. Normalization and completeness of the initial dissection are particularly important to PTC patients.

Establishment and characterization of a cell line from the head kidney of golden pompano Trachinotus ovatus and its application in toxicology and virus susceptibility

A cell line derived from the head kidney of golden pompano Trachinotus ovatus (TOHK) was established and characterized in this study. The TOHK cells grew most rapidly at 28° C and the optimum foetal bovine serum concentration in L-15 medium was 10%. The TOHK cells have a diploid chromosome number of 2N = 54. The transfection efficiency of TOHK cells was 7·5% at the 15th passage and 72% at the 40th passage. The transfection efficiency in TOHK cells was high, so these cells are suitable for foreign gene expression. The cytotoxic effects of heavy metals and extracellular products from Vibrio anguillarum and Vibrio alginolyticus were demonstrated in TOHK cells, so this TOHK cell line could also be applied in environmental monitoring of heavy metals and pathogenic bacteria. TOHK cell line showed high virus susceptibility, such as grouper nervous necrosis virus (GNNV) and Singapore grouper iridovirus (SGIV). Then, TOHK cell line could be used for the study of viral pathogenesis and the development of antiviral strategies.

Subjective well-being amongst migrant children in China: unravelling the roles of social support and identity integration

BACKGROUND

Migrant children refer to rural children who accompany one or both parents to urban area. Empirical evidence showed that compared with their urban counterparts, migrant children had poorer developmental, emotional and psychological health.

METHOD

A sample of 1306 migrant children were recruited to examine the characteristics of migrant children and investigate the effects of identity integration, support and socioeconomic factors (e.g. age, gender, type of school, family socioeconomic status, city type) on their subjective wellbeing.

RESULTS

Children with higher levels of identity integration, social support, family socioeconomic status, who attended public school and who lived in the third-tiered city of Weihai demonstrated better subjective wellbeing. Social support remained a strong predictor for subjective wellbeing, despite a significant mediating effect of identity integration.

CONCLUSIONS

These results highlight the need for policymakers and practitioners alike to address individual factors pertaining to psychological adjustments, as well as social determinants of subjective wellbeing in the context of migration.

[Multi-disciplinary treatment increases the survival rate of late stage pharyngeal, laryngeal or cervical esophageal cancers treated by free jejunal flap reconstruction after cancer resection]

OBJECTIVE

To investigate the survival status of patients with pharyngeal, laryngeal or cervical esophageal cancers, who received free jejunal flap (FJF) to repair the defects following tumor resection, and to analyze the effect of multi-disciplinary treatment on their survival.

METHODS

Fifty-eight patients with pharyngeal, laryngeal or cervical esophageal cancer underwent free jejunal flap (FJF) reconstruction after cancer resection between 2010 and 2013. All their clinical records were reviewed and analyzed.

RESULTS

The success rate of flap transplantation was 91.4% (53/58). The 2-year overall survival rates (OSR) of cervical esophageal cancer and hypopharyngeal cancer patients were 67.5% and 49.3%, respectively, both were significantly better than that of laryngeal cancer. The main causes of death were local recurrence and distant metastases. The group with no short-term complications had a better two-year OSR (59.0%) than the group with short-term complications (46.6%), however, the difference between them was not significant (P=0.103). The 2-year survival rate of the initial treatment group was 65.0%, better than that of the salvage treatment group (49.4%), but the difference was not significant (P=0.051). For the stage III and IV patients, the multi-disciplinary treatment group had a significantly better 2-year OSR (64.7%) than the single or sequential treatment group (37.0%, P=0.016).

CONCLUSIONS

Free jejunal flap reconstruction is an ideal option for repairing the cervical digestive tract circumferential defects caused by tumor resection with a high success rate and a low mortality. Compared with the single or sequential treatment, multi-disciplinary treatment can significantly improve the survival rate of late-stage hypopharyngeal and cervical esophageal cancer patients.

Erythropoietin promotes bone formation through EphrinB2/EphB4 signaling

Recent studies have demonstrated that erythropoietin (EPO) has extensive nonhematopoietic biological functions. However, little is known about how EPO regulates bone formation, although several studies suggested that EPO can affect bone homeostasis. In this study, we investigated the effects of EPO on the communication between osteoclasts and osteoblasts through the ephrinB2/EphB4 signaling pathway. We found that EPO slightly promotes osteoblastic differentiation with the increased expression of EphB4 in ST2 cells. However, EPO increased the expression of Nfatc1 and ephrinB2 but decreased the expression of Mmp9 in RAW264.7 cells, resulting in an increase of ephrinB2-expressing osteoclasts and a decrease in resorption activity. The stimulation of ephrinB2/EphB4 signaling via ephrinB2-Fc significantly promoted EPO-mediated osteoblastic differentiation in ST2 cells. EphB4 knockdown through EphB4 shRNA inhibited EPO-mediated osteoblastic phenotypes. Furthermore, in vivo assays clearly demonstrated that EPO efficiently induces new bone formation in the alveolar bone regeneration model. Taken together, these results suggest that ephrinB2/EphB4 signaling may play an important role in EPO-mediated bone formation.

PCR screening reveals considerable unexploited biosynthetic potential of ansamycins and a mysterious family of AHBA-containing natural products in actinomycetes

AIMS

Ansamycins are a family of macrolactams that are synthesized by type I polyketide synthase (PKS) using 3-amino-5-hydroxybenzoic acid (AHBA) as the starter unit. Most members of the family have strong antimicrobial, antifungal, anticancer and/or antiviral activities. We aimed to discover new ansamycins and/or other AHBA-containing natural products from actinobacteria.

METHODS AND RESULTS

Through PCR screening of AHBA synthase gene, we identified 26 AHBA synthase gene-positive strains from 206 plant-associated actinomycetes (five positives) and 688 marine-derived actinomycetes (21 positives), representing a positive ratio of 2·4-3·1%. Twenty-five ansamycins, including eight new compounds, were isolated from six AHBA synthase gene-positive strains through TLC-guided fractionations followed by repeated column chromatography. To gain information about those potential ansamycin gene clusters whose products were unknown, seven strains with phylogenetically divergent AHBA synthase genes were subjected to fosmid library construction. Of the seven gene clusters we obtained, three show characteristics for typical ansamycin gene clusters, and other four, from Micromonospora spp., appear to lack the amide synthase gene, which is unusual for ansamycin biosynthesis. The gene composition of these four gene clusters suggests that they are involved in the biosynthesis of a new family of hybrid PK-NRP compounds containing AHBA substructure.

CONCLUSIONS

PCR screening of AHBA synthase is an efficient approach to discover novel ansamycins and other AHBA-containing natural products.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work demonstrates that the AHBA-based screening method is a useful approach for discovering novel ansamycins and other AHBA-containing natural products from new microbial resources.

Effects of 1.8 GHz radiofrequency radiation on protein expression in human lens epithelial cells

OBJECTIVE

The aim of the present study was to observe the effects of 1.8 GHz radiofrequency (RF) radiation on the protein expression of human lens epithelial cells (hLECs) in vitro.

METHODS

The hLECs were exposed and sham-exposed to 1.8 GHz RF radiation (specific absorption rate (SAR) of 4 W/kg) for 2 h. After exposure, the proteins extracted from LECs were loaded on the Ettan MDLC system connected to the LTQ-Orbitrap MS for screening the candidate protein biomarkers induced by RF. The quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the levels of messenger RNA of candidate biomarkers. After the hLECs were exposed to 1.8 GHz RF (SAR of 2, 3 and 4 W/kg) for 2 h, the Western blot assay was utilized to measure the expression levels of the above-screened candidate protein biomarkers.

RESULTS

The results of shotgun proteomic analysis indicated that there were eight proteins with differential expression between exposure and sham exposure groups. The results of qRT-PCR showed that there were three genes with expressional differences (valosin containing protein (VCP), ubiquitin specific peptidase 35 (USP35) and signal recognition particle 68 kDa (SRP68)) between exposure and sham exposure groups. The results of Western blot assay exhibited that the expressional levels of VCP and USP35 proteins significantly increased and the expressional level of protein SRP68 significantly decreased in hLECs exposed to 1.8 GHz RF radiation (SAR of 3 and 4 W/kg) for 2 h when compared with the corresponding sham groups (p < 0.05).

CONCLUSION

The shotgun proteomics technique can be applied to screen the proteins with differential expression between hLECs exposed to 1.8 GHz RF and hLECs sham-exposed to 1.8 GHz RF, and three protein biomarkers associated with RF radiation were validated by Western blot assay.

Perceived parenting and risk for major depression in Chinese women

BACKGROUND

In Western countries, a history of major depression (MD) is associated with reports of received parenting that is low in warmth and caring and high in control and authoritarianism. Does a similar pattern exist in women in China?

METHOD

Received parenting was assessed by a shortened version of the Parental Bonding Instrument (PBI) in two groups of Han Chinese women: 1970 clinically ascertained cases with recurrent MD and 2597 matched controls. MD was assessed at personal interview.

RESULTS

Factor analysis of the PBI revealed three factors for both mothers and fathers: warmth, protectiveness, and authoritarianism. Lower warmth and protectiveness and higher authoritarianism from both mother and father were significantly associated with risk for recurrent MD. Parental warmth was positively correlated with parental protectiveness and negatively correlated with parental authoritarianism. When examined together, paternal warmth was more strongly associated with lowered risk for MD than maternal warmth. Furthermore, paternal protectiveness was negatively and maternal protectiveness positively associated with risk for MD.

CONCLUSIONS

Although the structure of received parenting is very similar in China and Western countries, the association with MD is not. High parental protectiveness is generally pathogenic in Western countries but protective in China, especially when received from the father. Our results suggest that cultural factors impact on patterns of parenting and their association with MD.

Evaluation of adenovirus vectors containing serotype 35 fibers for tumor targeting

There is growing evidence from in vitro studies that subgroup B adenoviruses (Ad) can overcome the limitations in safety and tumor transduction efficiency seen with commonly used subgroup C serotype 5-based vectors. In this study, we confirm that the expression level of the B-group Ad receptor, CD46, correlates with the grade of malignancy of cervical cancer in situ. We also demonstrate the in vivo properties of Ad5-based vectors that contain the B-group Ad serotype 35 fiber (Ad5/35) in transgenic mice that express CD46 in a pattern and at a level similar to humans. Upon intravenous and intraperitoneal injection, an Ad5/35 vector did not efficiently transduce normal tissue, but was able to target metastatic or intraperitoneal tumors that express CD46 at levels comparable to human tumors. When an oncolytic Ad5/35-based vector was employed, in both tumor models antitumor effects were observed. Furthermore, injection of Ad5/35 vectors into CD46 transgenic mice caused less innate toxicity than Ad5 vectors. Our data demonstrate that Ad vectors that target CD46 offer advantages over Ad5-based vectors for treatment of cancer.

GRB2-mediated recruitment of GAB2, but not GAB1, to SF-STK supports the expansion of Friend virus-infected erythroid progenitor cells

Friend virus induces the development of erythroleukemia in mice through the interaction of a viral glycoprotein, gp55, with a truncated form of the Stk receptor tyrosine kinase, short form-Stk (Sf-Stk), and the EpoR. We have shown previously that the ability of Sf-Stk to participate in the transformation of Friend virus-infected cells requires the kinase activity and Grb2-binding site of Sf-Stk. Here we show that Grb2 heterozygous mice exhibit decreased susceptibility to Friend erythroleukemia and that expansion of erythroid progenitors in response to infection requires the C-terminal SH3 domain of Grb2. A fusion protein in which the Grb2-binding site in Sf-Stk is replaced by Gab2, supports the growth of progenitors from mice lacking Sf-Stk, whereas a Sf-Stk/Gab1 fusion protein does not. Gab2 is expressed in spleens from Friend virus-infected mice, co-immunoprecipitates with Sf-Stk and is tyrosine phosphorylated in the presence of Sf-Stk. Mice with a targeted deletion in Gab2 are less susceptible to Friend erythroleukemia and the expansion of erythroid progenitor cells in response to infection can be rescued by expression of Gab2, but not Gab1. Taken together, these data indicate that a Sf-Stk/Grb2/Gab2 complex mediates the growth of primary erythroid progenitor cells in response to Friend virus.

Deep mantle structure and the postperovskite phase transition

Seismologists have known for many years that the lowermost mantle of the Earth is complex. Models based on observed seismic phases sampling this region include relatively sharp horizontal discontinuities with strong zones of anisotropy, nearly vertical contrasts in structure, and small pockets of ultralow velocity zones (ULVZs). This diversity of structures is beginning to be understood in terms of geodynamics and mineral physics, with dense partial melts causing the ULVZs and a postperovskite solid-solid phase transition producing regional layering, with the possibility of large-scale variations in chemistry. This strong heterogeneity has significant implications on heat transport out of core, the evolution of the magnetic field, and magnetic field polarity reversals.

[The expression of BDNF and NT-3 in dorsal root ganglion following peripheral and central axotomy--an immunohistochemical study]

OBJECTIVE

To explore the expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-3(NT-3) in dorsal root ganglion (DRG) following peripheral and central axotomy.

METHODS

Fifteen male adult cats were divided into intact group, peripheral axotomy group and central axotomy group. The ten cats of the latter two groups were subjected to unilateral peripheral cut and central processes cut respectively. The animals were allowed to survive 4 days long; L5 DRG was taken from each animal and made into frozen sections 20 microns thick. The sections were stained using antisera of BDNF and NT-3 respectively by immunohistchemical ABC method. The neuronal numbers of BDNF and NT-3 of the three groups were counted and compared.

RESULTS

The positive products of BDNF were mainly distributed in small to medium sized neurons (13-57 microns) while those of NT-3 were mainly in large sized neurons (57-100 microns). The neuronal numbers of BDNF and NT-3 in peripheral and central axotomy groups (24.1 +/- 3.5, 29.4 +/- 5.2; 19.4 +/- 2.4, 20.2 +/- 1.9) increased significantly than those of intact group (12.1 +/- 2.2, 13.3 +/- 2.9), P < 0.01. And the neuronal numbers of BDNF and NT-3 in peripheral axotomy groups were more than those of central axotomy group(P < 0.05).

CONCLUSION

The results indicate that peripheral axotomy and central axotomy lead to the increase of the expression of BDNF and NT-3 in DRG neurons. And the effect of peripheral axotomy is greater than that of central axotomy.

Loading estimates of lead, copper, cadmium, and zinc in urban runoff from specific sources

Urban stormwater runoff is being recognized as a substantial source of pollutants to receiving waters. A number of investigators have found significant levels of metals in runoff from urban areas, especially in highway runoff. As an initiatory study, this work estimates lead, copper, cadmium, and zinc loadings from various sources in a developed area utilizing information available in the literature, in conjunction with controlled experimental and sampling investigations. Specific sources examined include building siding and roofs; automobile brakes, tires, and oil leakage; and wet and dry atmospheric deposition. Important sources identified are building siding for all four metals, vehicle brake emissions for copper and tire wear for zinc. Atmospheric deposition is an important source for cadmium, copper, and lead. Loadings and source distributions depend on building and automobile density assumptions and the type of materials present in the area examined. Identified important sources are targeted for future comprehensive mechanistic studies. Improved information on the metal release and distributions from the specific sources, along with detailed characterization of watershed areas will allow refinements in the predictions.

Induced apoptosis supports spread of adenovirus vectors in tumors

Selectively replicating viruses hold promise as anticancer agents. To eliminate the tumor, these viruses must efficiently spread throughout the tumor and induce oncolysis. We hypothesized that viral release and spread could be supported by apoptosis induced after assembly of de novo-produced virions in tumor cells. As a model to test this, we employed an adenovirus vector that replicated in human tumor cell lines. Expression of a dominant-negative I-kappaB from this vector sensitized tumor cells to recombinant human tumor necrosis factor alpha (TNF-alpha)-mediated apoptosis. We found that apoptosis induced during viral DNA replication compromised virus production, whereas apoptosis induced after virion assembly enhanced viral release from infected cells and dissemination. Electron microscopy demonstrated that viral particles were associated with or included in apoptotic bodies whose phagocytosis by neighboring cells provides a potential means for viral spread. Apoptosis induced after viral replication also supported spread in vivo, in subcutaneous tumors or liver metastases, resulting in a delay of tumor growth. Our findings could be applicable to other selectively replicating viruses or antitumor strategies that involve application of proapoptotic or cytolytic agents.

Tumor-specific gene expression in hepatic metastases by a replication-activated adenovirus vector

Clinical applications of tumor gene therapy require tumor-specific delivery or expression of therapeutic genes in order to maximize the oncolytic index and minimize side effects. This study demonstrates activation of transgene expression exclusively in hepatic metastases after systemic application of a modified first-generation (E1A/E1B-deleted) adenovirus vector (AdE1-) in mouse tumor models. The discrimination between tumors and normal liver tissue is based on selective DNA replication of AdE1- vectors in tumor cells. This new AdE1- based vector system uses homologous recombination between inverted repeats to mediate precise rearrangements within the viral genome. As a result of these rearrangements, a promoter is brought into conjunction with a reporter gene creating a functional expression cassette. Genomic rearrangements are dependent upon viral DNA replication, which in turn occurs specifically in tumor cells. In a mouse tumor model with liver metastases derived from human tumor cells, a single systemic administration of replication activated AdE1- vectors achieved transgene expression in every metastasis, whereas no extra-tumoral transgene induction was observed. Here we provide a new concept for tumor-specific gene expression that is also applicable for other conditionally replicating adenovirus vectors.

[Synthesis and spectroscopic studies of new N-functionalized macrocyclic compounds and complex]

Three new N-functionalized tetraazamacrocyclic compounds, C-messo-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane- N,N',N",N'"-tetrakis (ethyl acetate) (A), C-messo-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra- azacyclotetradecane-N,N,'N",N'"-tetraacetic acid (H4L) and the hydrobromide of H4L have been synthesized and the complex Na2[NiL].2C2H5OH has been prepared as well. The macroyclic compounds and the complex have been studied by electronic spectrum, infrared spectrum, 1H NMR, MS and elemental analysis.

Electrospray ionization-mass spectrometry study of the interaction of cisplatin-adducted oligonucleotides with human XPA minimal binding domain protein

Nucleotide excision repair (NER) is the process responsible for eliminating most ultraviolet (UV) radiation damage from DNA, as well as base alterations caused by a variety of mutagens. The xeroderma pigmentosum group A complementing protein (XPA) is believed to be involved in the early step of NER by recognizing and binding damaged DNA. Recent work has suggested that electrospray ionization-mass spectrometry (ESI-MS) can be an effective tool for the study of protein-DNA complexes. We have used ESI-Fourier transform ion cyclotron resonance (FTICR) mass spectrometry to examine the cisplatin-adducted oligonucleotide and its interaction with the human XPA minimal binding domain (XPA-MBD). High-resolution FTICR experiments of the binding products showed that both double-stranded damaged 20-mer and double-stranded undamaged 20-mer formed 1:1 noncovalent complexes with XPA-MBD. A 2:1 binding stoichiometry complex was also observed between XPA-MBD and double-stranded damaged 20-mer. Competitive binding experiments indicated only slightly preferential binding of XPA-MBD with the double-stranded damaged 20-mer compared to the undamaged 20-mer. The results demonstrate that ESI-FTICR mass spectrometry provides a fast and efficient approach for characterizing weak protein-DNA interactions such as the binding between XPA-MBD and a 20-mer oligonucleotide system.

[Applied anatomy of insular skin flap of nasolabial groove with retrograde superior labial artery]

In order to study the feasibiliy of the insular skin flap of the nasolabial groove with the retrograde superior labial artery, 8 adult cadavers were dissected and the relation between the superior labial artery and the skin of nasolabial groove was observed. The result revealed that superior labial artery was one of the branches of the facial artery and could be found in every cadaver. The diameter of the artery was 0.8 +/- 0.1 mm and the length was about 90 mm. The left and right facial arteries were connected with each other in the mid-line in the formation of the arcuate artery. The arcuate artery lay within the submucous tissue beyond the vermilion border about 6 mm. The concomitant veins were constant. If the facial artery being sectioned was beyond its initial site of superior labial artery, the skin of nasolabial groove on the same side could receive blood supply from contralateral supperior labial artery. The conclusion was that the insular skin flap of the nasolabial groove with the retrograde superior labial artery could be used in patients, because it had support from anatomical research.

Human nucleotide excision repair protein XPA: extended X-ray absorption fine-structure evidence for a metal-binding domain

The ubiquitous, multi-enzyme, nucleotide excision repair (NER) pathway is responsible for correcting a wide range of chemically and structurally distinct DNA lesions in the eukaryotic genome. Human XPA, a 31 kDa, zinc-associated protein, is thought to play a major NER role in the recognition of damaged DNA and the recruitment of other proteins, including RPA, ERCC1, and TFIIH, to repair the damage. Sequence analyses and genetic evidence suggest that zinc is associated with a C4-type motif, C105-X2-C108-X17-C126-X2-C129, located in the minimal DNA binding region of XPA (M98-F219). The zinc-associated motif is essential for damaged DNA recognition. Extended X-ray absorption fine structure (EXAFS) spectra collected on the zinc associated minimal DNA-binding domain of XPA (ZnXPA-MBD) show directly, for the first time, that the zinc is coordinated to the sulfur atoms of four cysteine residues with an average Zn-S bond length of 2.34+/-0.01 A. XPA-MBD was also expressed in minimal medium supplemented with cobalt nitrate to yield a blue-colored protein that was primarily (>95%) cobalt associated (CoXPA-MBD). EXAFS spectra collected on CoXPA-MBD show that the cobalt is also coordinated to the sulfur atoms of four cysteine residues with an average Co-S bond length of 2.33+/-0.02 A.

Structural features of the minimal DNA binding domain (M98-F219) of human nucleotide excision repair protein XPA

XPA, an essential protein in nucleotide excision repair (NER), interacts with damaged DNA and other proteins (RPA, ERCC1 and TFIIH) to remove a wide variety of chemically and structurally distinct DNA lesions from the eukaryotic genome. To understand the structural basis for the role of XPA in the repair process, the structure of the minimal DNA binding domain of human XPA [XPA-MBD (M98-F219)] was studied by NMR spectroscopy. A three-dimensional structure for XPA-MBD was generated using distance geometry and simulated annealing methods from NOE-based distance restraints, hydrogen bond and Zn-S distance restraints, and dihedral restraints. The structure calculations indicate that XPA-MBD contains elements of well-defined secondary structure interspaced with disordered loops organized into two non-interactive sub-domains: a zinc-binding core (D101-K137) and a loop-rich domain (L138-F219). The zinc-associated core contains an antiparallel beta-sheet (Y102-C105 and K110-M113) and an alpha-helix (C126-K137) separated by a poorly defined turn, reminiscent of the structure of the zinc-binding domain of the chicken erythroid transcription factor GATA-1 when bound to its cognate DNA sequence. The loop-rich domain contains a triple-strand antiparallel beta-sheet (L138-T140, L182-M178 and K163-K167), three loops (K151-L162, N169-D177 and Q208-F219) and three alpha-helices (K141-L150, K183-W194 and Q197-R207). The XPA-MBD structure is discussed in terms of known functions: binding single- and double-stranded DNA and binding RPA.

Purification, characterization and gene sequence analysis of a novel cytochrome c co-induced with reductive dechlorination activity in Desulfomonile tiedjei DCB-1

The sulfate-reducing bacterium, Desulfomonile tiedjei DCB-1, conserves energy for growth from reductive dechlorination of 3-chlorobenzoate via halorespiration. To understand this respiratory process better, we examined electron carriers from different cellular compartments of D. tiedjei. A 50-kDa cytochrome from the membrane fraction was found to be co-induced with dechlorination activity. This inducible cytochrome was extracted from the membrane fractions by Tris-HCl buffer containing ammonium sulfate at 35% saturation and was purified to electrophoretic homogeneity by phenyl superose, Mono Q, and hydroxyapatite chromatography. The purified cytochrome had a high-spin absorption spectrum. In a pH titration experiment, the absorption spectrum of the inducible cytochrome shifted to low spin at pH 13.2. The midpoint potential of the inducible cytochrome at pH 7.0 was -342 mV. The NH2-terminal amino acid sequence of the inducible cytochrome was determined and was used to obtain inverse PCR products containing the sequence of the gene encoding the inducible cytochrome. The ORF was 1398 bp and coded for a protein of 52.6 kDa. Two c-type heme-binding domains were identified in the COOH-terminal half of the protein. A putative signal peptide of 26 residues was found at the NH2-terminal end. The protein sequence was not found to have substantial sequence similarity to any other sequence in GenBank. We conclude that this is a c-type cytochrome substantially different from previously characterized c-type cytochromes.