Lipases secreted by a gut bacterium inhibit arbovirus transmission in mosquitoes.

Arboviruses are etiological agents of various severe human diseases that place a tremendous burden on global public health and the economy; compounding this issue is the fact that effective prophylactics and therapeutics are lacking for most arboviruses. Herein, we identified 2 bacterial lipases secreted by a Chromobacterium bacterium isolated from Aedes aegypti midgut, Chromobacterium antiviral effector-1 (CbAE-1) and CbAE-2, with broad-spectrum virucidal activity against mosquito-borne viruses, such as dengue virus (DENV), Zika virus (ZIKV), Japanese encephalitis virus (JEV), yellow fever virus (YFV) and Sindbis virus (SINV). The CbAEs potently blocked viral infection in the extracellular milieu through their lipase activity. Mechanistic studies showed that this lipase activity directly disrupted the viral envelope structure, thus inactivating infectivity. A mutation in the lipase motif of CbAE-1 fully abrogated the virucidal ability. Furthermore, CbAEs also exert lipase-dependent entomopathogenic activity in mosquitoes. The anti-arboviral and entomopathogenic properties of CbAEs render them potential candidates for the development of novel transmission control strategies against vector-borne diseases.

Adiponectin inhibits ROS/NLRP3 inflammatory pathway through FOXO3A to ameliorate oral submucosal fibrosis.

Oral submucous fibrosis (OSF) is an oral condition characterized by chronic progression, which may lead to the development of malignancy. Currently, available treatments for OSF only provide temporary relief of symptoms, and there is a limited availability of effective interventions that can effectively cure this condition. In this study, we aimed to investigate whether adiponectin (APN) could ameliorate OSF and the mechanisms involved in it. First, human oral mucosal fibroblasts (HOMFs) were cultured, an OSF model was established using arecoline, and APN and Imiquimod treatment were administered. Then we overexpressed NLRP3 and knocked down FOXO3A. FOXO3A, fibrosis-related factors (ɑ-SMA, COL1A, CTGF), TGF-ß1/Smad3 signaling-related factors (TGF-ß1, p-Smad3, Smad3), NLRP3 inflammasome-related factors (NLRP3, Caspase-1, IL-1ß), and ROS levels were evaluated. Finally, we explored the effect of APN on OSF in mice by in vivo experiments. We found that arecoline significantly increased ɑ-SMA, COL1A, CTGF, and TGF-ß1 expressions and promoted Smad3 phosphorylation, while APN significantly inhibited the elevation of these fibrosis-related factors. ROS production was significantly elevated in HOMFs after arecoline treatment, while APN treatment inhibited ROS production. However, the addition of Imiquimod and overexpression of NLRP3 exhibited a trend of elevated ROS, resisting the inhibitory effect of APN. Furthermore, adding Imiquimod and overexpression of NLRP3 elevated ɑ-SMA, COL1A and CTGF and activated TGF-ß1/Smad3 signaling pathway. Additionally, knockdown of FOXO3A enhanced APN-inhibited ɑ-SMA and COL1A. In vivo experiments further confirmed that APN ameliorated OSF in mice by inhibiting ROS/NLRP3 inflammatory pathway. In conclusion, APN ameliorated arecoline-induced OSF by promoting FOXO3A expression and downregulating the ROS/NLRP3 pathway.

Metaproteomics Characterizes the Human Gingival Crevicular Fluid Microbiome Function in Periodontitis.

Periodontitis is the leading cause of tooth loss in adults worldwide. The human proteome and metaproteome characterization of periodontitis is not clearly understood. Gingival crevicular fluid samples were collected from eight periodontitis and eight healthy subjects. Both the human and microbial proteins were characterized by liquid chromatography coupled with high-resolution mass spectrometry. A total of 570 human proteins were found differentially expressed, which were primarily associated with inflammatory response, cell death, cellular junction, and fatty acid metabolism. For the metaproteome, 51 genera were identified, and 10 genera were found highly expressed in periodontitis, while 11 genera were downregulated. The analysis showed that microbial proteins related to butyrate metabolism were upregulated in periodontitis cases. In particular, correlation analysis showed that the expression of host proteins related to inflammatory response, cell death, cellular junction, and lipid metabolism correlates with the alteration of metaproteins, which reflect the changes of molecular function during the occurrence of periodontitis. This study showed that the gingival crevicular fluid human proteome and metaproteome could reflect the characteristics of periodontitis. This might benefit the understanding of the periodontitis mechanism.

Immediate histologic correlation in patients with different HPV genotypes and ages: a single center analysis in China.

BACKGROUND: Human papillomavirus (HPV) has been confirmed as a major causative factor for malignant transformation of cervical epithelial cells and for the development of cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. We carried out this study to investigate the association of different HPV genotypes and ages with immediate histological cervical lesions in opportunistic screening patients in a single center. METHODS: A total of 1,661 samples with biopsy-confirmed histologic findings were collected from the gynecological clinic of our hospital between October 2017 and May 2020 for analysis. The distribution of single-type HPV genotypes in CIN of different severities and the age-dependent prevalence for single-type HPV infection were analyzed. RESULTS: In both CIN2 and CIN3 group, HPV16, 58, 52, 33 and 31/18 were detected as top 5 high-risk human papillomavirus (hrHPV) types, which accounts for 89.25% and 88.54% of single HPV infection incidence respectively. Besides, not a single case of HPV45 was found in CIN2 and CIN3. HPV16 was the dominant genotype in both CIN2 and CIN3, accounted for 46.24% and 55.21%, respectively. The prevalence of HPV16 was the most frequent in all the age groups, except ≥ 65 years group in CIN3, and almost one in three HPV16-positive patients were diagnosed with high grade CIN. The peak of the incidence of CIN3 was observed at 25 ~ 34 years (33.68%), followed by 35 ~ 44 years (31.58%). CONCLUSION: High grade CIN peak at 25 ~ 44 years, women of this age are recommended for normative screening if conditions permit. HPV16-positive patients should be given high priority in opportunistic screening, while the single-center data suggesting a low risk of CIN2/3 in HPV45-positive patients. For women ≥ 65 years old, patients infected with other HPV types should be also taken seriously. In general, HPV16, 58, 52, 33, 31 and 18 were the most common genotypes in CIN2/3, and a vaccine including these predominant genotypes might be of great significance for cervical cancer prevention in China.

Systolic heart failure induced by butylparaben in zebrafish is caused through oxidative stress and immunosuppression.

Due to Butylparaben (BuP) widespread application in cosmetics, food, pharmaceuticals, and its presence as an environmental residue, human and animal exposure to BuP is common, potentially posing hazards to both human and animal health. Congenital heart disease is already a serious problem. However, the effects of BuP on the developing heart and its underlying mechanisms remain unclear. Here, zebrafish embryos were exposed to environmentally and human-relevant concentrations of BuP (0.6 mg/L, 1.2 mg/L, and 1.8 mg/L, calculated but not measured) at 6 h post-fertilization (hpf) and were treated until 72 hpf. Exposure to BuP led to cardiac morphological defects and cardiac dysfunction in zebrafish embryos, manifesting symptoms similar to systolic heart failure. The etiology of BuP-induced systolic heart failure in zebrafish embryos is multifactorial, including cardiomyocyte apoptosis, endocardial and atrioventricular valve damage, insufficient myocardial energy, impaired Ca2+ homeostasis, depletion of cardiac-resident macrophages, cardiac immune non-responsiveness, and cardiac oxidative stress. However, excessive accumulation of reactive oxygen species (ROS) in the cardiac region and cardiac immunosuppression (depletion of cardiac-resident macrophages and cardiac immune non-responsiveness) may be the predominant factors. In conclusion, this study indicates that BuP is a potential hazardous substance that can cause adverse effects on the developing heart and provides evidence and insights into the pathological mechanisms by which BuP leads to cardiac dysfunction. It may help to prevent the BuP-based congenital heart disease heart failure in human through ameliorating strategies and BuP discharge policies, while raising awareness to prevent the misuse of preservatives.

A qualitative and quantitative analysis of the human gingival crevicular fluid proteome and metaproteome.

Gingival crevicular fluid (GCF) is an integral part of oral fluid that plays a special role in maintaining the structure of junctional epithelium and defending against bacterial infection. In this study, we comprehensively analysed the composition of the human GCF proteome and metaproteome simultaneously to obtain multidimensional information about GCF. A total of 3680 human proteins (2540 with at least two unique peptides) were identified in the normal GCF sample, and their functions were mainly associated with immune function and inflammation. Among these proteins, 1874 proteins could be quantified by the iBAQ algorithm, and their abundances spanned a dynamic range of six orders of magnitude. For the GCF metaproteome, a total of 3082 proteins and 69 genera were found. In addition, 16 genera were not identified by GCF metagenomic analysis. Compared to the saliva metaproteome, 32 genera were found to be in common. The protein quantitative analysis showed that the abundance of GCF metaproteome contributed to approximately 4.17% of the total GCF proteome. The top three most abundant genera were Fusobacterium, Corynebacterium, and Leptotrichia. The above data will be useful for future research on GCF-related diseases.

TRIM22 inhibits respiratory syncytial virus replication by targeting JAK-STAT1/2 signaling.

Respiratory syncytial virus (RSV) infection is a major cause of lower respiratory tract disease. Although RSV causes major economic losses every year, effective treatments have not been found so far. Recent studies have shown that the tripartite motif-containing (TRIM) superfamily plays an essential role in the immune response. In this study, we found that TRIM22 had an inhibitory effect on RSV infection, and downregulation of TRIM22 moderately enhanced RSV replication. Our data further demonstrated that RSV infection induced TRIM22 expression through the activation of JAK-STAT1/2 signaling. RSV infection also induced TRIM22 expression. Taken together, these data points showed that the TRIM family member, TRIM22, had an essential role in resisting RSV infection, and this effect was closely related to the JAK-STAT1/2 pathway. Our results provide promising evidence for a novel target for the prevention and treatment of RSV.

Comprehensive Analysis of Individual Variation in the Urinary Proteome Revealed Significant Gender Differences.

Disease biomarkers are the measurable changes associated with a pathophysiological process. Without homeostatic control, urine accumulates systematic changes in the body. Thus, urine is an attractive biological material for the discovery of disease biomarkers. One of the major bottlenecks in urinary biomarker discovery is that the concentration and composition of urinary proteins are influenced by many physiological factors. To elucidate the individual variation and related factors influencing the urinary proteome, we comprehensively analyzed the urine samples from healthy adult donors (aged 20-69 years). Co-expression network analysis revealed protein clusters representing the metabolic status, gender-related differences and age-related differences in urinary proteins. In particular, we demonstrated that gender is a crucial factor contributing to individual variation. Proteins that were increased in the male urine samples include prostate-secreted proteins and TIMP1, a protein whose abundance alters under various cancers and renal diseases; however, the proteins that were increased in the female urine samples have known functions in the immune system. Nine gender-related proteins were validated on 85 independent samples by multiple reaction monitoring. Five of these proteins were further used to build a model that could accurately distinguish male and female urine samples with an area under curve value of 0.94. Based on the above results, we strongly suggest that future biomarker investigations should consider gender as a crucial factor in experimental design and data analysis. Finally, reference intervals of each urinary protein were estimated, providing a baseline for the discovery of abnormalities.

Effect of different short-term tillage management on nitrogen-fixing bacteria community in a double-cropping paddy field of southern China.

Soil nitrogen (N)-fixing bacteria community plays an important role in the N cycling process in soil, but there is still limited information about how the soil microbes that drive this process to respond to combined application of tillage and crop residue management under the double-cropping rice (Oryza sativa L.) paddy field in southern of China. Therefore, the effects of 6-years short-term tillage treatment on soil N-fixing bacteria community under the double-cropping rice paddy field in southern China were studied by using the polymerase chain reaction-denaturing gradient gel electrophoresis method. The field experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), rotary tillage with crop residue removed as control (RTO). The results showed that the diversity index and richness index of cbbLR and nifH genes with CT, RT, and NT treatments were increased, compared with RTO treatment. Compared with RTO treatment, the abundance of cbbLR gene with CT, RT, and NT treatments were increased by 6.54, 4.73, and 2.78 times, respectively. Meanwhile, the abundance of nifH gene with CT, RT, and NT treatments were 5.32, 3.71, and 2.45 times higher than that of RTO treatment. The results also indicated that soil autotrophic Azotobacter and nitrogenase activity with CT and RT treatments were significantly higher (p < .05) than that of RTO treatment. There was an obvious difference in characteristic of soil N-fixing bacteria community between the application of crop residue and without crop residue input treatments. In summary, the results indicated that the abundance of N-fixing bacteria community in the double-cropping rice paddy field increased with conventional tillage and rotary tillage practice.

Effects of tillage management on soil carbon decomposition and its relationship with soil chemistry properties in rice paddy fields.

Decreasing the soil organic carbon (SOC) decomposition is critical to improve the quality of the soil and mitigate atmospheric CO2 emissions. To improve the ability to protect the SOC by optimizing tillage management, this study investigated the laboratory-based SOC mineralization (decomposition) and soil chemical properties under different tillage practices, including no tillage with straw mulch (NTS), rotary tillage with straw incorporated (RTS), moldboard plow tillage with straw incorporated (CTS) and moldboard plow tillage with straw removal (CT). Soil samples of six sampling dates from April 2017 to October 2018 were incubated at 25 °C and 70% water holding capacity for 60 d. Repeated Variance Analyses were conducted to compare the means of different treatments. The results showed that the average cumulative SOC mineralization (Cm) at the 0-5 cm soil depth was 7.09 g CO2 kg-1 soil under NTS, which was higher (P < 0.05) than that of the other treatments. However, the C mineralizability at both the 0-5 and 5-10 cm soil depths were lower (P < 0.05) under the NTS (0.16 and 0.15 g CO2 g-1 SOC) compared with the CTS and CT. Non-microbial CO2 emissions (CO2 emissions in sterilized soil) contributed to the lower C mineralizability under NTS, due to the lower mineralizability (0.041-0.089 g CO2 g-1 SOC) of sterilized soil under this treatment. Furthermore, some of the abiotic factors (e.g., C/N ratio and SOC content) significantly correlated with the Cm and C mineralizability. These factors might be critical for the ability to protect SOC under NTS. In summary, conservation tillage is an optimal management due to its protection on SOC, and part of this protection appeared to have been contributed by the soil abiotic factors, which were formed by long-term tillage management.

Analysis of the role of the human papillomavirus 16/18 E7 protein assay in screening for cervical intraepithelial neoplasia: a case control study.

BACKGROUND: Cervical cancer is the second-most common gynecological cancer, early screening plays a key role in the diagnosis and treatment of cervical intraepithelial neoplasia (CIN). Sustained E7 protein expression is the pathological basis for CIN and cervical cancer. METHODS: We collected the cervical cell samples of women who visited the gynecological clinic of Peking Union Medical College Hospital between September 2018 and September 2019 and submitted them to the high-risk human papillomavirus (Hr-HPV) test. We performed a magnetic particle-based chemiluminescence enzyme immunoassay to analyze the HPV16/18 E7 protein level in CIN of different severities and compared the results with those of cervical pathology (gold standard) and the HPV test. RESULTS: The positive rate of HPV16/18 E7 protein increased with the severity of CIN: 26.6% in normal tissue, 58.3% in CIN1, and 70.6% in CIN2 or higher (CIN2+). For CIN2+, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the E7 protein were 70.6, 67.9, 52.2, and 82.3%, respectively. These values of the HPV test were 86.8, 44.5, 43.7, and 87.1%, respectively. With the combination of the E7 protein assay and HPV test, the specificity for diagnosing CIN2+ was 78.1%, which was significantly higher than that of the HPV test alone. CONCLUSIONS: HPV16/18 E7 protein level is correlated with the severity of CIN and has a high concordance rate with the pathological result. For cervical cancer screening, the combination of HPV16/18 E7 protein assay and HPV test improves the CIN diagnostic specificity, detection rate, and detection accuracy.

Correction to: Analysis of the role of the human papillomavirus 16/18 E7 protein assay in screening for cervical intraepithelial neoplasia: a case control study.

An amendment to this paper has been published and can be accessed via the original article.

Circulating microRNA-21 as Stable Blood-Based Markers for Patients With ISR After PCI.

It recently has been reported that the in-stent restenosis (ISR) of expanded area after percutaneous coronary intervention (PCI) within six months can become a serious postoperative complication. A real-time quantitative PCR was used to analyze the expression of serum miR-21 in 33 ISR and 37 non-ISR patients after PCI. Expression of miR-21 was significantly higher in the ISR group compared with that in the NISR group, and a similar trend also occurred in factor- (TNF-α) level, Interleukin -6 (IL-6) level, and plaque area (PLA). However, a contrary trend occurred in the external elastic membrane area (EEM) and minimal lumen area (MLA). This study suggests that the increased expression of serum miR-21 is related to ISR after PCI, and miR-21 can be a new predictor of ISR.

Microbial carbon source utilization in rice rhizosphere and non-rhizosphere soils in a 34-year fertilized paddy field.

Carbon (C) is playing an important role in regulating soil nutrient cycling, maintaining soil fertility and crop yield, but there is still need to further study on how C source utilization characteristic respond to soil physical and chemical properties change with different fertilizer treatments under a double-cropping rice (Oryza sativa L.) field in southern China. Therefore, the effects of 34-year long-term fertilizer regime on C source utilization characteristic in rice rhizosphere and non-rhizosphere soils under a double-cropping rice field in southern China were studied by using 18 O-H2 O method in the present paper. The field experiments were included four fertilizer treatments: mineral fertilizer alone (MF), rice straw and mineral fertilizer (RF), 30% organic manure and 70% mineral fertilizer (OM), and without fertilizer input as control (CK). The results showed that microbial biomass C content, basal respiration of soil microorganism and microbial growth rate in rice rhizosphere and non-rhizosphere soils with OM and RF treatments were significantly higher (p < .05) than that of CK treatment. The microbial C utilization efficiency (CUE) in rhizosphere soil with MF and CK treatments were significantly higher (p < .05) than that of OM treatment, but there was no significantly difference (p > .05) in microbial CUE in non-rhizosphere soil between MF, RF, OM, and CK treatments. In the different parts of soil, the microbial biomass C content and basal respiration of soil microorganism in rhizosphere soil were higher than that of non-rhizosphere soil, but the microbial growth rate and microbial CUE in non-rhizosphere soil were higher than that of rhizosphere soil. Compared with CK and MF treatments, the metabolic capacity of soil microorganism to exogenic C source with RF and OM treatments were significantly higher (p < .05) than that of MF and CK treatments. The largest type of exogenic C source used by soil microorganism was carboxylic acids, followed by amino acid and carbohydrate, and complex compounds was the smallest. In the different parts of soil, the metabolic capacity of soil microorganism to the types of exogenic C source in non-rhizosphere soil was higher than that of rhizosphere soil. The redundancy analysis results indicated that there had obvious difference in utilization characteristic of soil microorganism to exogenic C source among different fertilizer treatments. In conclusion, this results indicated that characteristic of soil C source utilization were significantly changed under different long-term fertilizer condition.

Plasma miRNA-155 Levels Predict Atrial Fibrillation Recurrence after Cardioversion.

BACKGROUND: MicroRNAs (miRNAs) are widely involved in the regulation of physiological processes, such as cell proliferation, differentiation, apoptosis, angiogenesis, and lipid metabolism. They might be associated with the pathological process of atrial fibrillation (AF). The purpose of our study is to investigate whether plasma miRNA-155 levels have a relationship with AF recurrence. METHODS: A total of 110 patients with AF were studied, all with successful cardioversion. We measured the expression of plasma miRNA-155 in the recurrent group (n = 30) and in the nonrecurrent group (n = 80) by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, the serumal levels of B-type natriuretic peptide (BNP), total cholesterol (TC), and fasting blood glucose (FBG) in the groups were determined by using an automatic biochemical analyzer, and an immunoenzymatic method was applied to determine the serumal levels of tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), and interleukin-6 (IL-6). The left atrial diameter (LAD) and left ventricular ejection fraction (EF) of all patients were measured by using echocardiography. RESULTS: Our RT-PCR analysis found that miRNA-155 was significantly upregulated in the recurrent group compared with the nonrecurrent group. These increases of LAD and the levels of BNP, TNF-α, CRP, and IL-6 in the recurrent group were also revealed to be relative to those in the nonrecurrent group. There were no differences in the levels of TC and FBG, as well as in EF, between the groups. Moreover, miRNA-155 expression was observed to correlate positively with these outcomes of LAD, BNP, TNF-α, CRP, IL-6, and LAD. A diagnostic significance of predicting AF recurrence for plasma miRNA-155 was elucidated via ROC curve analysis. CONCLUSIONS: Our findings revealed that plasma miRNA-155 can present an ability to calculate AF recurrence after cardioversion.

Utilization of carbon sources in the rice rhizosphere and nonrhizosphere soils with different long-term fertilization management.

Carbon (C) plays an important role in the interaction between plant and rhizosphere microbial communities, but there is still limited information about how C source utilization soil microbial structure responds to soil fertility changes under the double-cropping rice (Oryza sativa L.) system in Southern China paddy fields. Therefore, the effects of long-term (33 years) fertilizer regimes on the characteristics of C utilization in both rhizosphere and nonrhizosphere soils under double-cropping rice fields in Southern China were investigated by using the metagenome sequencing technology. The experiment began in 1986, and included five fertilizer treatments: without fertilizer input (CK), chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic matter, and 70% chemical fertilizer (LOM), and 60% organic matter and 40% chemical fertilizer (HOM). The results showed that the relative abundance of Gemmatimonadetes and Planctomycetia in both the rhizosphere and nonrhizosphere soils was increased by application of rice straw residue and organic manure, whereas the relative abundance of Gammaproteobacteria and Nitrospira was promoted by application of inorganic fertilizers. The largest group of clusters of orthologous groups of proteins categories was "amino acid transport and metabolism" with 16.46% unigenes, followed by "general function prediction only" (12.23%). Regarding the gene ontology categories, biological process were the largest category (174 949, 46.40%), followed by cellular component (126 766, 33.62%), and molecular function (110 353, 29.26%). The principal coordinate analysis indicated that different parts of the root zone were the most important factors affecting the variation of C source utilization bacteria community, and the different fertilizer treatments were the second important factor affecting the variation of C source utilization bacteria community. As a result, the application of fertilization practices had significant effects on the abundance and community composition of C source utilization microbes in paddy soils. The results showed that the combined application of rice straw residue or organic manure with chemical fertilizer practices significantly increases the C source utilization of soil microorganisms in double-cropping rice fields.

Preclinical evaluation of severely defective manganese-based nanocrystal as a liver-specific contrast media for MR imaging: comparison with Gd-EOB-DTPA and MnDPDP.

Manganese-based (chemically formulated of KMnF3) nanocrystal was evaluated as a liver-specific contrast agent for MR imaging and its imaging performance was also compared with those of two commercial hepatobiliary contrast media (Gd-EOB-DTPA and MnDPDP). KMnF3 nanocrystal was post-treated using a plasma technique to cause severe defects, leading to appropriate water dispersibility and high relaxivity. Severely defective KMnF3 nanocrystal (SD-KMnF3) has characteristic high tolerance, as evidenced by cytotoxicity on the macrophage cell, and acute and subchronic toxicity on the healthy mouse. SD-KMnF3 showed better hepatic MR imaging as the T 1 relaxation time of the liver decreased to only 17% of the control group, compared to 22% of the control group for Gd-EOB-DTPA (P < 0.01) and 42% of the control group for MnDPDP (P < 0.001). As applied to MR imaging of the allograft orthotopic model of liver cancer, statistical studies demonstrated that SD-KMnF3 significantly improved the tumor's contrast-to-noise ratio, compared with Gd-EOB-DTPA (P < 0.01) and MnDPDP (P < 0.01) by spin-echo pulse sequence, and even better performance (P < 0.001) by gradient-echo sequence. Our findings indicate that SD-KMnF3 could serve as a hepatic contrast agent for imaging liver cancer such as hepatocarcinoma or metastatic lesions.

Oxygen plasma-fragmented KMnF3 nanoparticle benefits contrast enhancement for MRI of a patient-derived tumor xenograft model.

Magnetic nanoparticles (NPs) are emerging as promising candidates for the next generation of image contrast agents and their performance is largely dependent on physicochemical properties. In this paper, a new type of 'top-down' fabrication technique was developed to synthesize ultrasmall magnetic NPs as a contrast enhancer. In a detailed, home-made oxygen plasma generator, fragments of larger KMnF3 NPs (22 nm) were broken down into smaller (<5 nm) particles with enhanced hydrophilicity. As massive activated oxygen species were produced during the process, the plasma was able to severely etch the NPs, and vacuum UV light irradiated them heavily as well, leaving them with weak crystallinity, splitting them into ultrafine particles. Also their surface transformed from hydrophobic to hydrophilic by oxidizing the passivated ligand, evidenced by the spectroscopy and microscopy results. The fragmented NPs are characteristic of unprecedented high longitudinal relaxivity (r1 = 35.52 mM-1.s-1) and appropriate biocompatibility. In a healthy mouse, the ultrafine NPs did not exert observable toxicity, this was evaluated by histology of the main organs and hemogram analysis, including kidney and liver function analysis. More interestingly, the ultrasmall NPs had a very long circulation time, as its blood half-life was around 20 h. When applied as a contrast enhancer for MRI of the patient-derived tumor xenograft model, the accumulation of KMnF3 NPs within the tumor had an average of 12.13% ID per gram, which greatly shortened the relaxation time of the tumor. Therefore the control-to-noise ratio was significantly enhanced, relative to the same dosage of Gadopentetetic acid (Magvenist) (P < 0.001). Our primary results demonstrate that fragmentation of the NPs via our home-made oxygen plasma technique might be an effective route for fabricating ultrasmall NPs, and benefit their contrast effect when applied as MRI enhancers for clinical diagnosis of tumors.

A neuron-specific antiviral mechanism prevents lethal flaviviral infection of mosquitoes.

Mosquitoes are natural vectors for many etiologic agents of human viral diseases. Mosquito-borne flaviviruses can persistently infect the mosquito central nervous system without causing dramatic pathology or influencing the mosquito behavior and lifespan. The mechanism by which the mosquito nervous system resists flaviviral infection is still largely unknown. Here we report that an Aedes aegypti homologue of the neural factor Hikaru genki (AaHig) efficiently restricts flavivirus infection of the central nervous system. AaHig was predominantly expressed in the mosquito nervous system and localized to the plasma membrane of neural cells. Functional blockade of AaHig enhanced Dengue virus (DENV) and Japanese encephalitis virus (JEV), but not Sindbis virus (SINV), replication in mosquito heads and consequently caused neural apoptosis and a dramatic reduction in the mosquito lifespan. Consistently, delivery of recombinant AaHig to mosquitoes reduced viral infection. Furthermore, the membrane-localized AaHig directly interfaced with a highly conserved motif in the surface envelope proteins of DENV and JEV, and consequently interrupted endocytic viral entry into mosquito cells. Loss of either plasma membrane targeting or virion-binding ability rendered AaHig nonfunctional. Interestingly, Culex pipien pallens Hig also demonstrated a prominent anti-flavivirus activity, suggesting a functionally conserved function for Hig. Our results demonstrate that an evolutionarily conserved antiviral mechanism prevents lethal flaviviral infection of the central nervous system in mosquitoes, and thus may facilitate flaviviral transmission in nature.

Transmission-blocking antibodies against mosquito C-type lectins for dengue prevention.

C-type lectins are a family of proteins with carbohydrate-binding activity. Several C-type lectins in mammals or arthropods are employed as receptors or attachment factors to facilitate flavivirus invasion. We previously identified a C-type lectin in Aedes aegypti, designated as mosquito galactose specific C-type lectin-1 (mosGCTL-1), facilitating the attachment of West Nile virus (WNV) on the cell membrane. Here, we first identified that 9 A. aegypti mosGCTL genes were key susceptibility factors facilitating DENV-2 infection, of which mosGCTL-3 exhibited the most significant effect. We found that mosGCTL-3 was induced in mosquito tissues with DENV-2 infection, and that the protein interacted with DENV-2 surface envelop (E) protein and virions in vitro and in vivo. In addition, the other identified mosGCTLs interacted with the DENV-2 E protein, indicating that DENV may employ multiple mosGCTLs as ligands to promote the infection of vectors. The vectorial susceptibility factors that facilitate pathogen invasion may potentially be explored as a target to disrupt the acquisition of microbes from the vertebrate host. Indeed, membrane blood feeding of antisera against mosGCTLs dramatically reduced mosquito infective ratio. Hence, the immunization against mosGCTLs is a feasible approach for preventing dengue infection. Our study provides a future avenue for developing a transmission-blocking vaccine that interrupts the life cycle of dengue virus and reduces disease burden.