Bio­Inspired Magnetic­Responsive Supramolecular­Covalent Semi­Convertible Hydrogel.

Bio-inspired magnetic-responsive hydrogel is confined in exceedingly narrow spaces for soft robots and biomedicine in either gel state or magnetofluidic sol state. However, the motion of the gel state magnetic hydrogel will be inhibited in various irregular spaces due to the fixed shape and size and the sol-state magnetofluid gel may bring unpredictable residues in the confined narrow space. Inspired by the dynamic liquid lubricating mechanism of biological systems, novel magnetic-responsive semi-convertible hydrogel (MSCH) is developed through imbedding magnetic-responsive gelatin and amino-modified Fe3O4 nanoparticles network into the covalent network of polyvinyl alcohol, which can be switched between gel state and gel-sol state in response to magnetic stimuli. It can be attributed the disassembly of triple-helix structures of the gelatin under the action of the magnetic field, driven by force from the magnetic particles conjugated on the gelatin chain through electrostatic interactions, while the covalent network retains the hydrogel structural integrity. This leads to a sol layer on the MSCH surface enabling the MSCH to pass effectively through the confined channel or obstacle under magnetic field. The present MSCH will provide an alternative mode for magnetic field-related soft robots or actuators.

Multi-organ hereditary hemorrhagic telangiectasia: A case report.

BACKGROUND: Type 2 hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant disease and is associated with ALK1 gene mutations. Type 2 HHT patients primarily suffer from recurrent bleeding. There is currently no promising treatment. CASE SUMMARY: A 5-year-old Chinese patient (III23) was admitted to Zhongshan Hospital for recurrent melena occurring over 2 mo. She had been experiencing epistaxis for years and had been diagnosed with idiopathic pulmonary hypertension 4 mo before presentation. Abdominal computed tomography examination showed hepatic arteriovenous malformation. Gene testing revealed a c.1121G>A mutation on the ALK1 gene. According to the international diagnostic criteria, this patient was diagnosed with HHT. In addition, 8 more family members exhibited HHT symptoms to varying degrees. Gene testing in 5 family members (2 with HHT symptoms and 3 without HHT symptoms) revealed the ALK1 c.1121G>A mutation in the 2 family members with HHT symptoms. This missense mutation results in the substitution of arginine for glutamine at amino acid position 374 (R374Q) in the conserved functional kinase domain of ALK1. Biological studies revealed that this mutation decreased the kinase activity of ALK1 and impeded the phosphorylation of its substrate Smad1. Moreover, the R374Q mutant downregulated the protein level of collagen-1, a fibrogenic factor, indicating abnormal fiber generation during vascular formation. CONCLUSION: The R374Q mutant of ALK1 and its subsequent influence on fiber generation highly indicated its pathogenic role in this family with type 2 HHT. Detection of this gene mutation will facilitate early diagnosis of suspected type 2 HHT patients, and mechanistic studies will provide insights for future therapy.

Ubiquitylation of cyclin C by HACE1 regulates cisplatin-associated sensitivity in gastric cancer.

BACKGROUND: Cyclin C (CCNC) was reported to take part in regulating mitochondria-derived oxidative stress under cisplatin stimulation. However, its effect in gastric cancer is unknown. This study aimed to investigate the role of cyclin C and its ubiquitylation in regulating cisplatin resistance in gastric cancer. METHODS: The interaction between HECT domain and ankyrin repeat-containing E3 ubiquitin-protein ligase 1 (HACE1) and cyclin C was investigated by GST pull-down assay, co-immunoprecipitation and ubiquitylation assay. Mitochondria-derived oxidative stress was studied by MitoSOX Red assay, seahorse assay and mitochondrial membrane potential measurement. Cyclin C-associated cisplatin resistance was studied in vivo via xenograft. RESULTS: HACE1 catalysed the ubiquitylation of cyclin C by adding Lys11-linked ubiquitin chains when cyclin C translocates to cytoplasm induced by cisplatin treatment. The ubiquitin-modified cyclin C then anchor at mitochondira, which induced mitochondrial fission and ROS synthesis. Depleting CCNC or mutation on the ubiquitylation sites decreased mitochondrial ROS production and reduced cell apoptosis under cisplatin treatment. Xenograft study showed that disrupting cyclin C ubiquitylation by HACE1 conferred impairing cell apoptosis response upon cisplatin administration. CONCLUSIONS: Cyclin C is a newly identified substrate of HACE1 E3 ligase. HACE1-mediated ubiquitylation of cyclin C sheds light on a better understanding of cisplatin-associated resistance in gastric cancer patients. Ubiquitylation of cyclin C by HACE1 regulates cisplatin-associated sensitivity in gastric cancer. With cisplatin-induced nuclear-mitochondrial translocation of cyclin C, its ubiquitylation by HACE1 increased mitochondrial fission and mitochondrial-derived oxidative stress, leading to cell apoptosis.

Phosphocreatine attenuates Gynura segetum-induced hepatocyte apoptosis via a SIRT3-SOD2-mitochondrial reactive oxygen species pathway.

Purpose: To investigate the mitochondria-related mechanism of Gynura segetum (GS)-induced apoptosis and the protective effect of phosphocreatine (PCr), a mitochondrial respiration regulator. Methods: First, the mechanism was explored in human hepatocyte cell line. The mitochondrial oxidative stress was determined by fluorescence assay. The level of sirtuin 3 (SIRT3), acetylated superoxide dismutase 2 (Ac-SOD2), SOD2, and apoptosis were detected by Western blotting. Mito-TEMPO and cell lines of viral vector-mediated overexpression of SIRT3 and SIRT3H248Y were used to further verify the mechanism of GS-induced apoptosis. GS-induced liver injury mice models were built by GS through intragastric administration and interfered by PCr through intraperitoneal injection. A total of 30 C57BL/6J mice were assigned to 5 groups and treated with either saline, PCr (100 mg/kg), GS (30 g/kg), or PCr (50 or 100 mg/kg)+GS (30 g/kg). Liver hematoxylin and eosin (HE) staining, immunohistochemical analysis, and blood biochemical evaluation were performed. Results: GS induced hepatocyte apoptosis and elevated levels of mitochondrial ROS in L-02 cells. The expression of SIRT3 was decreased. Downregulation of SIRT3 was associated with increased levels of Ac-SOD2, which is the inactivated enzymatic form of SOD2. Conversely, when overexpressing SIRT3 in GS-treated cells, SOD2 activity was restored, and mitochondrial ROS levels and hepatocyte apoptosis declined. Upon administration of PCr to GS-treated cells, they exhibited a significant upregulation of SIRT3 and were protected against apoptosis. In animal experiments, serum ALT level and mitochondrial ROS of the mice treated with GS and 50 mg/kg PCr were significantly attenuated compared with only GS treated. The changes in SIRT3 expression were also consistent with the in vitro results. In addition, immunohistochemical analysis of the mouse liver showed that Ac-SOD2 was decreased in the PCr and GS co-treated group compared with GS treated group. Conclusion: GS caused liver injury by dysregulating mitochondrial ROS generation via a SIRT3-SOD2 pathway. PCr is a potential agent to treat GS-induced liver injury by mitochondrial protection.

Genome-wide screening identifies oncofetal lncRNA Ptn-dt promoting the proliferation of hepatocellular carcinoma cells by regulating the Ptn receptor.

Oncofetal genes are genes that express abundantly in both fetal and tumor tissues yet downregulated or undetected in adult tissues, and can be used as tumor markers for cancer diagnosis and treatment. Meanwhile, long noncoding RNAs (lncRNAs) are known to play crucial roles in the pathogenesis of hepatocellular carcinoma (HCC), including tumor growth, proliferation, metastasis, invasion, and recurrence. We performed a genome-wide screening using microarrays to detect the lncRNA expression profiles in fetal livers, adult livers, and liver cancer tissues from mice to identify oncofetal lncRNAs in HCC. From the microarray data analysis, we identified lncRNA Ptn-dt as a possible oncofetal gene. Both in vitro and in vivo experiments results confirmed that overexpression of Ptn-dt significantly promoted the proliferation of mouse HCC cells. RNA pulldown assay showed that Ptn-dt could interact with the HuR protein. Interestingly, miR-96 binds with HuR to maintain its stability as well. Overexpression of lncRNA Ptn-dt led to the downregulation of miR-96, which might be due to the interaction between Ptn-dt and HuR. Meanwhile, previous studies have reported that Ptn can promote tumor growth and vascular abnormalization via anaplastic lymphoma kinase (Alk) signaling. In our study, we found that overexpression of Ptn-dt could promote the expression of Alk through repressing miR-96 via interacting with HuR, thus enhancing the biologic function of Ptn. In summary, a new oncofetal lncRNA Ptn-dt is identified, and it can promote the proliferation of HCC cells by regulating the HuR/miR-96/Alk pathway and Ptn-Alk axis.

Overexpression of HACE1 in gastric cancer inhibits tumor aggressiveness by impeding cell proliferation and migration.

HACE1 E3 ligase was discovered to be down-regulated in several cancers while its role in regulating tumors was merely understood. This study aimed to explore the specific effect of HACE1 played in gastric tumorigenesis and its potential mechanism. HACE1's expression was found significantly lower in gastric cancer tissues compared with the adjacent normal tissues (P < 0.001). Its protein level in gastric cancer negatively correlated to tumor pathological differentiation (P = 0.019). And in gastric cancer patients with TNM I-IIIa, those with lower HACE1 protein level had poorer overall survival (P = 0.025). Studies, in vivo and in vitro, showed that overexpressing HACE1 inhibited tumor proliferation and migration, and enhanced cell apoptosis. Besides, ectopic expression of HACE1 down-regulated the protein level of ß-catenin and inhibited the activity of the Wnt/ß-catenin signaling pathway. All the cellular functions were abolished when we overexpressed inactive HACE1-deltaHECT. Above all, we demonstrated that HACE1 E3 ligase played a suppressive role in gastric tumorigenesis and inhibited the activity of the Wnt/ß-catenin signaling pathway. Circumventing the decline of HACE1 in early stage of carcinoma may impede the tumorigenesis and malignant process of gastric cancer.

Distribution and phylogenetic analysis of Culex flavivirus in mosquitoes in China.

Culex flavivirus (CxFV) is an insect-specific virus of the genus Flavivirus. CxFV strains have been isolated from Cx. pipiens, Cx. quinquefasciatus, and other Cx. species in Asia, Africa, North America, Central America and South America. CxFV was isolated for the first time in China in 2006. As this is a novel flavivirus, we explored the distribution and genetic characteristics of Culex flavivirus in China. A total of 46,649 mosquitoes were collected in seven provinces between 2004 and 2012 and were analysed in 871 pools. 29 CxFV RNAs from Cx. pipiens, Cx. tritaeniorhynchus, Anopheles Sinensis, and Culex spp. tested positive for CxFV in real-time RT-PCR. 6 CxFV strains were isolated from Cx. species collected in Shandong, Henan, and Shaanxi provinces, while no virus or viral RNA was detected in samples from Sichuan, Chongqing, Hubei, and Fujian. Phylogenetic analysis of the envelope gene indicated that Chinese strains formed a robust subgroup of genotype 1, together with viruses from the United States and Japan. This study demonstrates that the geographic distribution of CxFV in China is widespread, but geographical boundaries to spread are apparent. Our findings suggest that CxFV can infect various mosquito species in nature.

Spatial and seasonal variations of the air pollution index and a driving factors analysis in china.

In this study, the daily air pollution index (API) of 110 cities based on ground monitoring was conducted on the 2011 data set from the Ministry of Environmental Protection of China. The pollutant concentrations, seasonal variations, and spatial autocorrelations were evaluated. The results show that the major principal pollutants in China are inhalable particles. In addition, the total number of clean days (API ≤ 50) is apparently smaller in the northern cities than in the southern cities as a result of fuel utilization and large-scale organized central heating. Seasonally, air pollution is most severe in winter and is caused by low-frequency rainfall, strong northwest winds, dry climate, and high energy consumption; this is followed by spring, which is a season of frequent sandstorms. According to spatial autocorrelation analysis, clusters with high API value agglomeration (High-High clusters) are mainly concentrated in the middle and northern parts of China, whereas clusters with low API agglomeration (Low-Low clusters) are principally concentrated in the southern parts of China due to a favorable climate and abundant rainfall. Meteorological data, including wind speed and temperature, have great impacts on API. The air quality effects of industrial structure, energy use, urban greening, and traffic congestion were also analyzed. With the ecological function of purifying the air, industries that use natural resources and urban greening could help to reduce API, whereas secondary industry and gas use, which have a positive coefficient, increase the API value. The risk of exposure to poor air quality is largest in the winter, smallest in the summer, and remains relatively unchanged in the spring and autumn.

[An outbreak of imported dengue fever from Myanmar to the border of China, with its viral molecular epidemiological features].

OBJECTIVE: To understand the epidemiologic characteristics of dengue fever, imported from Myanmar to the border of Yunnan province, China. Viral molecular epidemiologic features were also studied. METHODS: Questionnaires were used on each diagnosed, suspected dengue fever, case or unknown cases with fever when coming from Myanmar entering the port and hospitals in Ruili city of Yunnan province. Serum samples of these patients were collected to detect IgM antibody against dengue virus and RT-PCR assay. Homology and phylogenetic tree based on the whole nucleotide sequence of PrM-C and NS5 gene of dengue virus were further analyzed. RESULTS: A total of 103 sera were collected from patients at acute stage in Ruili city in July to November 2008. Among them, 49 cases were confirmed for dengue fever according to IgM and nucleic acid testings. Except one, other 48 cases were all imported into Ruili, from Myanmar. Of those, 18 patients were residents from Mujie city of Myanmar and hospitalized in Ruili and the rest 30 patients were Chinese citizens who had finished business and returned from Myanmar. Two isolates of serum samples from the imported cases were identified and both homology and phylogenetic analysis were performed, using the nucleotide sequences of PrM and NS5 genes. They were divided into dengue type 1 (RLB61) and dengue type 3 (RLC31) and were closer to the dengue virus strains isolated from Southeast Asia countries. CONCLUSION: It is confirmed that an epidemic of dengue fever which was imported from Myanmar to Ruili city of Yunnan province, China. Evidence also showed that both type I and III epidemic strains of dengue virus did exist in Mujie city of Myanmar in 2008.

Identification and isolation of Genotype-I Japanese encephalitis virus from encephalitis patients.

Historically, Japanese Encephalitis virus (JEV) genotype III (GIII) has been responsible for human diseases. In recent years, JEV genotype I (GI) has been isolated from mosquitoes collected in numerous countries, but has not been isolated from patients with encephalitis. In this study, we report recovery of JEV GI live virus and identification of JEV GI RNA from cerebrospinal fluid (CSF) of encephalitis patients in JE endemic areas of China. Whole-genome sequencing and molecular phylogenetic analysis of the JEV isolate from the CSF samples was performed. The isolate in this study is highly similar to other JEV GI strains which isolated from mosquitoes at both the nucleotide and deduced amino acid levels. Phylogenetic analysis based on the genomic sequence showed that the isolate belongs to JEV GI, which is consistent with the phylogenetic analysis based on the pre-membrane (PrM) and Glycoprotein genes. As a conclusion, this is the first time to isolate JEV GI strain from CSF samples of encephalitis patients, so continuous survey and evaluate the infectivity and pathogenecity of JEV GI strains are necessary, especially for the JEV GI strains from encephalitis patients. With respect to the latter, because all current JEV vaccines (live and inactivated are derived from JEV GIII strains, future studies should be aimed at investigating and monitoring cross-protection of the human JEV GI isolates against widely used JEV vaccines.

[Molecular characteristics of the full-length genome of two new Japanese encephalitis virus isolated from mosquitoes in Hubei province].

OBJECTIVE: To sequence and analyze the complete genome of two new Japanese encephalitis virus (JEV) strains isolated from mosquitoes collected in Hubei province in 2008, and to understand the molecular biological characteristics of JEV in this area. METHODS: RT-PCR was used to amplify the fragments of HBZG08-09 strain and HBZG08-55 strain with 16 pairs overlapping primers after they had been recovered and identified, then the full-length genome was obtained by sequencing and splicing. Biological sequence alignment, nucleotide and amino acid sequence analysis, phylogenetic analysis and analysis of amino acid differences were performed by the software of Clustal X (1.83), MegAlign, Mega (4.0) and Genedoc (3.2). RESULTS: The genome of two new strains were both 10 965 nucleotides in length with a single open reading frame from 96 to 10 392 coding for a 3432 amino acid poly-protein, the homology of nucleotide and amino acid sequence between two isolates were 98.2% and 99.7% respectively. Further study showed that the new strains were both belonging to genotype I. Two new strains were most closely related to isolates obtained from Henan and Zhejiang province in recent years. Compared with the live attenuated vaccine strain SA-14-14-2 in China, HBZG08-09 strain had 82 amino acid divergence; HBZG08-55 had 84 amino acid divergences. But the amino acid difference occurred in sites were not the key ones affecting the toxicity or antigenic of JEV. CONCLUSION: Two new JEV isolates were both belonging to genotype I, and the key sites of amino acid were not changed.