PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (283)
 

Clipboard (0)
None

Select a Filter Below

Journals
more »
Year of Publication
more »
1.  DNA as Sensors and Imaging Agents for Metal Ions 
Inorganic chemistry  2013;53(4):1925-1942.
Increasing interests in detecting metal ions in many chemical and biomedical fields have created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal ion-dependent DNAzymes and metal ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attaching these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detections. These sensors are highly sensitive (with detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of “dipstick tests”, portable fluorometers, computer-readable discs, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state, and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal ion sensing and imaging in many fields of applications.
doi:10.1021/ic4019103
PMCID: PMC3955431  PMID: 24359450
2.  The production of nitrous oxide (N2O) by the heme/nonheme diiron center of engineered myoglobins (FeBMbs) proceeds through a trans iron-nitrosyl dimer 
Denitrifying NO reductases are transmembrane protein complexes that are evolutionarily related to heme/copper terminal oxidases. They utilize a heme/nonheme diiron center to reduce two NO molecules to N2O. Engineering a nonheme FeB site within the heme distal pocket of sperm whale myoglobin has offered well-defined diiron clusters to investigate the mechanism of NO reduction in these unique active sites. In this study, we use FTIR spectroscopy to monitor the production of N2O in solution, and to show that the presence of a distal FeBII is not sufficient to produce the expected product. However, the addition of a glutamate side chain peripheral to the diiron site allows for 50% of productive single-turnover reaction. Unproductive reactions are characterized by resonance Raman spectroscopy as dinitrosyl complexes, where one NO molecule is bound to the heme iron to form a five-coordinate low-spin {FeNO}7 species with ν(FeNO)heme and ν(NO)heme at 522 and 1660 cm−1, and a second NO molecule is bound to the nonheme FeB site with a ν(NO)FeB at 1755 cm−1. Stopped-flow UV-vis absorption coupled with rapid-freeze-quench resonance Raman spectroscopy provide a detailed map of the reaction coordinates leading to the unproductive iron-nitrosyl dimer. Unexpectedly, NO binding to FeB is kinetically favored and occurs prior to the binding of a second NO to the heme iron, leading to a (six-coordinate low-spin heme-nitrosyl/FeB-nitrosyl) transient dinitrosyl complex with characteristic ν(FeNO)heme at 570 ± 2 cm−1 and ν(NO)FeB at 1755 cm−1. Without the addition of a peripheral glutamate, the dinitrosyl complex is converted to a dead-end product after the dissociation of the proximal histidine of the heme iron, but the added peripheral glutamate side chain in FeBMb2 lowers the rate of dissociation of the promixal histidine which in turn allows the (six-coordinate low-spin heme-nitrosyl/FeB-nitrosyl) transient dinitrosyl complex to decay with production of N2O at a rate of 0.7 s−1 at 4 °C. Taken together, our results support the proposed trans mechanism of NO reduction in NORs.
doi:10.1021/ja410542z
PMCID: PMC4004238  PMID: 24432820
3.  Direct EPR Observation of a Tyrosyl Radical in a Functional Oxidase Model in Myoglobin during both H2O2 and O2 Reactions 
Tyrosine is a conserved redox-active amino acid that plays important roles in heme-copper oxidases (HCO). Despite the widely proposed mechanism that involves a tyrosyl radical, its direct observation under O2 reduction condition remains elusive. Using a functional oxidase model in myoglobin called F33Y-CuBMb that contains an engineered tyrosine, we report herein direct observation of a tyrosyl radical during both reactions of H2O2 with oxidized protein and O2 with reduced protein by electron paramagnetic resonance spectroscopy, providing a firm support of the tyrosyl radical in the HCO enzymatic mechanism.
doi:10.1021/ja4091885
PMCID: PMC3955430  PMID: 24383850
4.  The Prognostic Value of Intermedin in Patients with Breast Cancer 
Disease Markers  2015;2015:862158.
This study aimed to evaluate the prognostic value of preoperative plasma intermedin levels in breast cancer patients. Plasma intermedin levels of 252 breast cancer women and 100 healthy women were determined using radioimmunoassay kit. Adverse event was defined as first local recurrence, distant metastasis, second primary cancer of another organ, or death from any cause during 5-year follow-up. Disease-free survival was defined as the time between surgery and the date of any adverse event whichever appeared first. Overall survival was defined from surgery to death for any cause. The relationships between plasma intermedin levels and clinical outcomes of breast cancer patients were evaluated using multivariate analysis. The results showed that preoperative plasma intermedin levels were substantially higher in patients than in healthy subjects using t-test. Intermedin was identified as an independent predictor for 5-year mortality, adverse event, disease-free survival, and overall survival using multivariate analysis. Based on receiver operating characteristic curve analysis, preoperative plasma intermedin levels had high predictive value for 5-year mortality and adverse event. In conclusion, preoperative plasma intermedin levels are highly associated with poor patient outcomes and intermedin may be a potential prognostic biomarker for patients with breast cancer.
doi:10.1155/2015/862158
PMCID: PMC4324930
5.  Post-cataract endophthalmitis caused by multidrug-resistant Stenotrophomonas maltophilia: clinical features and risk factors 
BMC Ophthalmology  2015;15:14.
Background
To report clinical features and risk factors of post-cataract surgery endophthalmitis (PE) due to Stenotrophomonas maltophilia.
Methods
A retrospective case review from December 10, 2010 to April 7, 2011 was performed at the Eye & ENT Hospital, Fudan University. Data were collected for surgical details, disease characteristics, antibiotic sensitivity of the pathogen, and treatment response. Visual outcomes were examined with a minimum follow-up of 12 months.
Results
Fourteen cases of S. maltophilia endophthalmitis were identified. The onset of infection occurred from 1–56 days postoperatively (median, 13.5 days). Obvious cellular reactions were found in all patients in the anterior chamber, along with the absence of pupil synechia. Retinal periphlebitis was an early sign of PE. S. maltophilia was positive in eight patients (57.1%). The fluids from aspiration tubes revealed the same bacteria, which were resistant to multiple drugs (e.g., amino glycosides, most of the β-lactams, aztreonam, imipenem, and ciprofloxacin), except levofloxacin. Compared with the culture-negative group, the infection was more rapid, more severe, and more difficult to control in the culture-positive group. Among 14 patients, 11 patients (78.6%) underwent pars plana vitrectomy (PPV) with intravitreal injection. Three patients had PPV twice, and three patients had intraocular lens and capsular bag removal. A final visual acuity of ≥20/100 was achieved by 13/14 patients (92.9%). Complications included retinal detachment in three cases (21.4%) and recurrence of infection in two cases (14.8%). Statistical analysis showed that age over 90 years and posterior capsule rupture were risk factors of infection (P = 0.034 and P = 0.034, respectively). The phacoemulsifier allowed potential contamination between the aspiration and irrigation tubes.
Conclusions
S. maltophilia should be considered a pathogenic organism of PE. The infection often occurs in older patients with posterior capsule rupture. Intravitreal or systemic administration of effective antibiotics and earlier initial PPV may contribute to better clinical outcomes. Tubes with connections between aspiration and irrigation should be avoided during surgery.
doi:10.1186/1471-2415-15-14
PMCID: PMC4320429  PMID: 25618260
Cataract surgery; Endophthalmitis; Intraocular lens; Drug resistance; Stenotrophomonas maltophilia
6.  Histone Chaperone-Mediated Nucleosome Assembly Process 
PLoS ONE  2015;10(1):e0115007.
A huge amount of information is stored in genomic DNA and this stored information resides inside the nucleus with the aid of chromosomal condensation factors. It has been reported that the repeat nucleosome core particle (NCP) consists of 147-bp of DNA and two copies of H2A, H2B, H3 and H4. Regulation of chromosomal structure is important to many processes inside the cell. In vivo, a group of histone chaperones facilitate and regulate nucleosome assembly. How NCPs are constructed with the aid of histone chaperones remains unclear. In this study, the histone chaperone-mediated nucleosome assembly process was investigated using single-molecule tethered particle motion (TPM) experiments. It was found that Asf1 is able to exert more influence than Nap1 and poly glutamate acid (PGA) on the nucleosome formation process, which highlights Asf1’s specific role in tetrasome formation. Thermodynamic parameters supported a model whereby energetically favored nucleosomal complexes compete with non-nucleosomal complexes. In addition, our kinetic findings propose the model that histone chaperones mediate nucleosome assembly along a path that leads to enthalpy-favored products with free histones as reaction substrates.
doi:10.1371/journal.pone.0115007
PMCID: PMC4303269  PMID: 25611318
7.  The Production of Nitrous Oxide by the Heme/Nonheme Diiron Center of Engineered Myoglobins (FeBMbs) Proceeds through a trans-Iron-Nitrosyl Dimer 
Denitrifying NO reductases are transmembrane protein complexes that are evolutionarily related to heme/copper terminal oxidases. They utilize a heme/nonheme diiron center to reduce two NO molecules to N2O. Engineering a nonheme FeB site within the heme distal pocket of sperm whale myoglobin has offered well-defined diiron clusters for the investigation of the mechanism of NO reduction in these unique active sites. In this study, we use FTIR spectroscopy to monitor the production of N2O in solution and to show that the presence of a distal FeBII is not sufficient to produce the expected product. However, the addition of a glutamate side chain peripheral to the diiron site allows for 50% of a productive single-turnover reaction. Unproductive reactions are characterized by resonance Raman spectroscopy as dinitrosyl complexes, where one NO molecule is bound to the heme iron to form a five-coordinate low-spin {FeNO}7 species with ν(FeNO)heme and ν(NO)heme at 522 and 1660 cm–1, and a second NO molecule is bound to the nonheme FeB site with a ν(NO)FeB at 1755 cm–1. Stopped-flow UV–vis absorption coupled with rapid-freeze-quench resonance Raman spectroscopy provide a detailed map of the reaction coordinates leading to the unproductive iron-nitrosyl dimer. Unexpectedly, NO binding to FeB is kinetically favored and occurs prior to the binding of a second NO to the heme iron, leading to a (six-coordinate low-spin heme-nitrosyl/FeB-nitrosyl) transient dinitrosyl complex with characteristic ν(FeNO)heme at 570 ± 2 cm–1 and ν(NO)FeB at 1755 cm–1. Without the addition of a peripheral glutamate, the dinitrosyl complex is converted to a dead-end product after the dissociation of the proximal histidine of the heme iron, but the added peripheral glutamate side chain in FeBMb2 lowers the rate of dissociation of the promixal histidine which in turn allows the (six-coordinate low-spin heme-nitrosyl/FeB-nitrosyl) transient dinitrosyl complex to decay with production of N2O at a rate of 0.7 s–1 at 4 °C. Taken together, our results support the proposed trans mechanism of NO reduction in NORs.
doi:10.1021/ja410542z
PMCID: PMC4004238  PMID: 24432820
8.  Rational Design of a Structural and Functional Nitric Oxide Reductase 
Nature  2009;462(7276):1079-1082.
Summary
Protein design provides an ultimate test of our knowledge about proteins and allows the creation of novel enzymes for biotechnological applications. While progress has been made in designing proteins that mimic native proteins structurally1–3, it is more difficult to design functional proteins4–8. In comparison to recent successes in designing non-metalloproteins4,6,7,9,10, it is even more challenging to rationally design metalloproteins that reproduce both the structure and function of native metalloenzymes5,8,11–20, since protein metal binding sites are much more varied than non-metal containing sites, in terms of different metal ion oxidation states, preferred geometry and metal ion ligand donor sets. Because of their variability, it has been difficult to predict metal binding site properties in silico, as many of the parameters for metal binding sites, such as force fields are ill-defined. Therefore, the successful design of a structural and functional metalloprotein will greatly advance the field of protein design and our understanding of enzymes. Here, we report a successful, rational design of a structural and functional model of a metalloprotein, nitric oxide reductase (NOR), by introducing three histidines and one glutamate, predicted as ligands in the active site of NOR, into the distal pocket of myoglobin. A crystal structure of the designed protein confirms that the minimized computer model contains a heme/non-heme FeB center that is remarkably similar to that in the crystal structure. This designed protein also exhibits NOR activity. This is the first designed protein that models both the structure and function of NOR, offering insight that the active site glutamate is required for both iron binding and activity. These results show that structural and functional metalloproteins can be rationally designed in silico.
doi:10.1038/nature08620
PMCID: PMC4297211  PMID: 19940850
9.  Meta-analyses on prevalence of selected Parkinson’s nonmotor symptoms before and after diagnosis 
Background
Nonmotor symptoms are common among patients with Parkinson’s disease (PD) and some may precede disease diagnosis.
Methods
We conducted a meta-analysis on the prevalence of selected nonmotor symptoms before and after PD diagnosis, using random-effect models. We searched PubMed (1965 through October/November 2012) for the following symptoms: hyposmia, constipation, rapid eye movement sleep behavior disorder, excessive daytime sleepiness, depression, and anxiety. Eligible studies were publications in English with original data on one or more of these symptoms.
Results
The search generated 2,373 non-duplicated publications and 332 met the inclusion criteria, mostly (n = 320) on symptoms after PD diagnosis. For all symptoms, the prevalence was substantially higher in PD cases than in controls, each affecting over a third of the patients. Hyposmia was the most prevalent (75.5% in cases vs. 19.1% in controls), followed by constipation (50% vs. 17.7%), anxiety (39.9% vs. 19.1%), rapid eye movement sleep behavior disorder (37.0% vs. 7.0%), depression (36.6% vs. 14.9%), and excessive daytime sleepiness (33.9% vs. 10.5%). We observed substantial heterogeneities across studies and meta-regression analyses suggested that several factors might have contributed to this. However, the prevalence estimates were fairly robust in several sensitivity analyses. Only 20 studies had data on any symptoms prior to PD diagnosis, but still the analyses revealed higher prevalence in future PD cases than in controls.
Conclusion
These symptoms are common among PD patients both before and after diagnosis. Further studies are needed to understand the natural history of nonmotor symptoms in PD and their etiological and clinical implications.
Electronic supplementary material
The online version of this article (doi:10.1186/2047-9158-4-1) contains supplementary material, which is available to authorized users.
doi:10.1186/2047-9158-4-1
PMCID: PMC4322463  PMID: 25671103
Parkinson’s disease; Nonmotor symptoms; Meta-analysis; Prevalence; Natural history
10.  Activation of the Ubiquitin Proteasome Pathway by Silk Fibroin Modified Chitosan Nanoparticles in Hepatic Cancer Cells 
Silk fibroin (SF) is a protein with bulky hydrophobic domains and can be easily purified as sericin-free silk-based biomaterial. Silk fibroin modified chitosan nanoparticle (SF-CSNP), a biocompatible material, has been widely used as a potential drug delivery system. Our current investigation studied the bio-effects of the SF-CSNP uptake by liver cells. In this experiment, the characterizations of SF-CSNPs were measured by particle size analysis and protein assay. The average size of the SF-CSNP was 311.9 ± 10.7 nm, and the average zeta potential was +13.33 ± 0.3 mV. The SF coating on the SF-CSNP was 6.27 ± 0.17 μg/mL. Moreover, using proteomic approaches, several proteins involved in the ubiquitin proteasome pathway were identified by analysis of differential protein expressions of HepG2 cell uptake the SF-CSNP. Our experimental results have demonstrated that the SF-CSNP may be involved in liver cancer cell survival and proliferation.
doi:10.3390/ijms16011657
PMCID: PMC4307326  PMID: 25588218
silk fibroin; chitosan nanoparticle; biomaterial; proteomics; ubiquitin proteasome pathway
11.  Deceased expression of prostatic acid phosphatase in primary sensory neurons after peripheral nerve injury 
Prostatic acid phosphatase (PAP) is expressed in nociceptive dorsal root ganglion (DRG) neurons and functions as an ectonucleotidase that dephosphorylates extracellular adenosine monophosphate (AMP) to adenosine to suppress pain via activating A1-adenosine receptor (A1R) in dorsal spinal cord. However, the effect of peripheral nerve injury on the expression of PAP has not been reported until now. In the present study we found that PAP expression in DRG neurons is significantly decreased from the 2nd day after peripheral nerve injury and reaches the bottom at the 14th. In addition, intrathecal PAP injection can reduce mechanical allodynia induced by spared nerve injury. Our findings suggest that the decrease of PAP is involved in pathophysiological mechanisms of neuropathic pain.
PMCID: PMC4314050
PAP; DRG; peripheral nerve injury; neuropathic pain
12.  Facile and efficient preparation of anisotropic DNA-functionalized gold nanoparticles and their regioselective assembly 
Journal of the American Chemical Society  2013;135(47):17675-17678.
Anisotropic nanoparticles can provide considerable opportunities for assembly of nanomaterials with unique structures and properties. However, most reported anisotropic nanoparticles are either difficult to prepare, have a low yield, or difficult to functionalize. Here we report a facile one-step solution-based method to prepare anisotropic DNA-functionalized gold nanoparticles (a-DNA-AuNP) with 96% yield and with high DNA density (120 ± 20 strands on the gold hemisphere surface). The method is based on the competition between a thiolated hydrophilic DNA and a thiolated hydrophobic phospholipid and has been applied to prepare a-DNA-AuNP with different sizes of nanoparticles and a variety of DNA sequences. In addition, DNA strands on the a-DNA-AuNP can be exchanged with other DNA strands with a different sequence. The anisotropic nature of the a-DNA-AuNPs allows regioselective hetero- and homo-nuclear assembly with high monodispersity, as well as regioselective functionalization of two different DNA strands for more diverse applications.
doi:10.1021/ja408033e
PMCID: PMC3902043  PMID: 24148071
13.  Interface-Induced Ordering of Gas Molecules Confined in a Small Space 
Scientific Reports  2014;4:7189.
The thermodynamic properties of gases have been understood primarily through phase diagrams of bulk gases. However, observations of gases confined in a nanometer space have posed a challenge to the principles of classical thermodynamics. Here, we investigated interfacial structures comprising either O2 or N2 between water and a hydrophobic solid surface by using advanced atomic force microscopy techniques. Ordered epitaxial layers and cap-shaped nanostructures were observed. In addition, pancake-shaped disordered layers that had grown on top of the epitaxial base layers were observed in oxygen-supersaturated water. We propose that hydrophobic solid surfaces provide low-chemical-potential sites at which gas molecules dissolved in water can be adsorbed. The structures are further stabilized by interfacial water. Here we show that gas molecules can agglomerate into a condensed form when confined in a sufficiently small space under ambient conditions. The crystalline solid surface may even induce a solid-gas state when the gas-substrate interaction is significantly stronger than the gas-gas interaction. The ordering and thermodynamic properties of the confined gases are determined primarily according to interfacial interactions.
doi:10.1038/srep07189
PMCID: PMC4244620  PMID: 25424443
14.  CSF biomarker changes precede symptom onset of mild cognitive impairment 
Neurology  2013;81(20):1753-1758.
Objective:
This study evaluated longitudinal CSF biomarker measures collected when participants were cognitively normal to determine the magnitude and time course of biomarker changes before the onset of clinical symptoms in subjects with mild cognitive impairment (MCI).
Methods:
Longitudinal CSF collection and cognitive assessments were performed on a cohort of 265 participants who were cognitively normal at their baseline assessment and subsequently developed MCI or dementia. CSF β-amyloid 1–42 (Aβ1–42), total tau (t-tau), and phosphorylated tau (p-tau) were determined longitudinally. Consensus diagnoses were completed annually. Cox regression analyses were performed, with baseline CSF values and time-dependent rate of change in CSF values as covariates (adjusted by baseline age, race, and education), in relation to time to onset of mild cognitive symptoms.
Results:
The mean time from baseline to onset of mild cognitive symptoms was 5.41 years. Increased risk of progressing from normal cognition to onset of clinical symptoms was associated with baseline values of Aβ1–42, p-tau, and the ratios of p-tau/Aβ1–42 and t-tau/Aβ1–42 (p < 0.002). Additionally, the rate of change in the ratios of t-tau/Aβ1–42 (p < 0.004) and p-tau/Aβ1–42 (p < 0.02) was greater among participants who were subsequently diagnosed with MCI.
Conclusions:
Baseline differences in CSF values were predictive of clinical symptoms that were a harbinger of a diagnosis of MCI more than 5 years before symptom onset, and continue to show longitudinal changes as cognitive symptoms develop, demonstrating that baseline and longitudinal changes in CSF biomarkers are evident during the preclinical phase of Alzheimer disease.
doi:10.1212/01.wnl.0000435558.98447.17
PMCID: PMC3821715  PMID: 24132375
15.  A Smart T1-weighted MRI Contrast Agent for Uranyl Cation based on a DNAzyme-Gadolinium Conjugate 
The Analyst  2013;138(21):6266-6269.
Rational design of smart MRI contrast agents with high specificity for metal ions remains to be a challenge. Here, we report a general strategy for the design of smart MRI contrast agents for detecting metal ions based on conjugation of a DNAzyme with a gadolinium complex. The 39E DNAzyme, which has high selectivity for UO22+, was conjugated to Gd(III)-DOTA and streptavidin. The binding of UO22+ to its 39E DNAzyme resulted in the dissociation of Gd(III)-DOTA from the massive streptavidin, leading to a decrease in T1 correlation time, and a change in MRI signal.
doi:10.1039/c3an01182h
PMCID: PMC3813883  PMID: 24005082
16.  Enhancement of oral bioavailability of cyclosporine A: comparison of various nanoscale drug-delivery systems 
A variety of nanoscale delivery systems have been shown to enhance the oral absorption of poorly water-soluble and poorly permeable drugs. However, the performance of these systems has seldom been evaluated simultaneously. The aim of this study was to compare the bioavailability enhancement effect of lipid-based nanocarriers with poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) to highlight the importance of the lipid composition, with cyclosporine A (CyA) as a model drug. CyA-loaded PLGA NPs, nanostructured lipid carriers (NLCs), and self-microemulsifying drug-delivery systems (SMEDDS) were prepared. The particle size of PLGA NPs (182.2±12.8 nm) was larger than that of NLCs (89.7±9.0 nm) and SMEDDS (26.9±1.9 nm). All vehicles are charged negatively. The entrapment efficiency of PLGA NPs and NLCs was 87.6%±1.6% and 80.3%±0.6%, respectively. In vitro release tests indicated that the cumulative release of CyA was lower than 4% from all vehicles, including Sandimmun Neoral®, according to the dialysis method. Both NLCs and SMEDDS showed high relative oral bioavailability, 111.8% and 73.6%, respectively, after oral gavage administration to beagle dogs, which was not statistically different from commercial Sandimmun Neoral®. However, PLGA NPs failed to achieve efficient absorption, with relative bioavailability of about 22.7%. It is concluded that lipid-based nanoscale drug-delivery systems are superior to polymeric NPs in enhancing oral bioavailability of poorly water-soluble and poorly permeable drugs.
doi:10.2147/IJN.S72560
PMCID: PMC4218918  PMID: 25378925
cyclosporine A; PLGA nanoparticle; nanostructured lipid carrier; self-microemulsifying drug-delivery systems; bioavailability
17.  Selective Delivery of an Anticancer Drug with Aptamer-Functionalized Liposomes to Breast Cancer Cells in Vitro and in Vivo 
Selective targeting of cancer cells is a critical step in cancer diagnosis and therapy. To address this need, DNA aptamers have attracted significant attention as possible targeting ligands. However, while their use in targeting cancer cells in vitro has been reported, their effectiveness has rarely been established in vivo. Here we report the development of a liposomal drug delivery system for targeted anticancer chemotherapy. Liposomes were prepared containing doxorubicin as a payload, and functionalized with AS1411, a DNA aptamer with strong binding affinity for nucleolin. AS1411 aptamer-functionalized liposomes increased cellular internalization and cytotoxicity to MCF-7 breast cancer cells as compared to non-targeting liposomes. Furthermore, targeted liposomal doxorubicin improved antitumor efficacy against xenograft MCF-7 breast tumors in athymic nude mice, attributable to their enhanced tumor tissue penetration. This study suggests that AS1411 aptamer-functionalized liposomes can recognize nucleolin overexpressed on MCF-7 cell surface, and therefore enable drug delivery with high specificity and selectivity.
doi:10.1039/C3TB20412J
PMCID: PMC3800741  PMID: 24159374
DNA aptamer; cancer targeting; nucleolin; liposome; targeted drug delivery; breast cancer
18.  Duration of Viraemia in Chinese Acute Sporadic Hepatitis E 
Purpose
Acute sporadic hepatitis E (ASHE) cases induced by hepatitis E virus genotype 4 (HEV-4) are increasing in China. Our study aimed to estimate the duration of HEV-4 viraemia in Chinese ASHE.
Methods
A total of 619 serum specimens from 499 ASHE patients were examined for the presence of HEV RNA. The association between viraemia detection and serum sampling time was compared between subtypes. The cumulative probability of HEV viraemia detection was determined using Kaplan-Meier survival analysis, and the viraemia duration was estimated.
Results
A total of 42.7% serum specimens were positive for HEV RNA and all the isolated strains were identified as genotype 4 and subsequently assigned to five subtypes. Among the patients infected with subtypes 4d and 4i, the time interval from the initiation of clinical symptoms to serum specimen sampling was shorter than that among the patients with subtypes 4a, 4b, and 4h. Kaplan-Meier analysis was conducted with 101 sequential specimens as well as with both 101 sequential specimens and 236 single negative specimens. The cumulative probability of HEV-4 viraemia detection was estimated to decline quickly to approximately 10% within 32 days after the initiation of clinical symptoms and then to decline very slowly to 5% by the 41st day and to zero by the 131st day.
Conclusions
The majority of ASHE cases maintain detectable HEV-4 viraemia within one month after onset, whereas a small portion of cases maintain long-term viraemia and may act as a reservoir for further transmission.
doi:10.1007/s10096-013-2007-5
PMCID: PMC4201985  PMID: 24241947
Hepatitis E virus; Genotype 4; Viraemia; Phylogenetic analysis; China
19.  Deficiency of asparagine synthetase causes congenital microcephaly and a progressive form of encephalopathy 
Neuron  2013;80(2):10.1016/j.neuron.2013.08.013.
SUMMARY
We analyzed four families that presented with a similar condition characterized by congenital microcephaly, intellectual disability, progressive cerebral atrophy and intractable seizures. We show that recessive mutations in the ASNS gene are responsible for this syndrome. Two of the identified missense mutations dramatically reduce ASNS protein abundance, suggesting that the mutations cause loss of function. Hypomorphic Asns mutant mice have structural brain abnormalities, including enlarged ventricles and reduced cortical thickness, and show deficits in learning and memory mimicking aspects of the patient phenotype. ASNS encodes asparagine synthetase, which catalyzes the synthesis of asparagine from glutamine and aspartate. The neurological impairment resulting from ASNS deficiency may be explained by asparagine depletion in the brain, or by accumulation of aspartate/glutamate leading to enhanced excitability and neuronal damage. Our study thus indicates that asparagine synthesis is essential for the development and function of the brain but not for that of other organs.
doi:10.1016/j.neuron.2013.08.013
PMCID: PMC3820368  PMID: 24139043
20.  Autophagy Facilitates Antibody-Enhanced Dengue Virus Infection in Human Pre-Basophil/Mast Cells 
PLoS ONE  2014;9(10):e110655.
Background
Dengue virus (DENV) infection can cause severe hemorrhagic disease in humans. Although the pathogenic mechanisms underlying severe DENV disease remain unclear, one of the possible contributing factors is antibody-dependent enhancement (ADE) which occurs when sub-neutralizing antibodies derived from a previous DENV infection enhance viral infection through interaction between virus-antibody complexes and FcR-bearing cells, such as macrophages and basophil/mast cells. Although recent reports showed that DENV induces autophagy, the relationship between antibody-enhanced DENV infection and autophagy is not clear.
Methodology/Principal Findings
We showed that sub-neutralizing antibodies derived from dengue patient sera enhanced DENV infection and autophagy in the KU812 pre-basophil-like cell line as well as the HMC-1 immature mast cell line. Antibody-enhanced DENV infection of KU812 cells increased the number of autophagosome vesicles, LC3 punctation, LC3-II accumulation, and p62 degradation over that seen in cells infected with DENV alone. The percentages of DENV envelope (E) protein-positive cells and LC3 puncta following antibody-enhanced DENV infection of KU812 cells were reduced by the autophagy inhibitor 3-MA. Antibody-enhanced DENV infection of HMC-1 cells showed co-localization of DENV E protein and dsRNA with autophagosomes, which was inhibited by 3-MA treatment. Furthermore, DENV infection and replication were reduced when KU812 cells were transfected with the autophagy-inhibiting Atg4BC74A mutant.
Conclusions/Significance
Our results demonstrate a significant induction of autophagy in antibody-enhanced DENV infection of pre-basophil-like KU812 and immature mast cell-like HMC-1 cells. Also, autophagy plays an important role in DENV infection and replication in these cells. Given the importance of ADE and FcR-bearing cells such as monocytes, macrophages and basophil/mast cells in dengue disease, the results provide insights into dengue pathogenesis and therapeutic means of control.
doi:10.1371/journal.pone.0110655
PMCID: PMC4199741  PMID: 25329914
21.  Diagnostic value of combining CA 19-9 and K-ras gene mutation in pancreatic carcinoma: a meta-analysis 
Aims: To assess diagnostic value of Carbohydrate Antigen 19-9 (CA 19-9), combined CA 19-9 and K-ras mutation in plasma DNA in diagnosing patients with pancreatic carcinoma. Materials and methods: MEDLINE, EMBASE, the Cochrane Library, Sinomed, CNKI and other databases, from established to November, 2013, were searched for initial studies. All the studies published in English or Chinese relating to the diagnostic value of CA 19-9 and K-ras gene mutation for patients with pancreatic cancer were collected. Methodological quality was assessed. The statistic software called “Meta-disc” (version 1.4) was used for data analysis. Results: 10 studies were included in this meta-analysis. The pooled sensitivity estimate for CA 19-9 (78%) was significantly higher than K-ras mutation (65%). While, for the specificity estimate, K-ras mutation (93%) was significantly higher than CA 19-9 (77%). The pooled DOR estimate for K-ras mutation (21.82) was significantly higher than CA 19-9 (18.36). SROC curves for K-ras mutation showed better diagnostic accuracy than CA 19-9. For CA 19-9 measurement, its diagnostic value decreased in differentiating pancreatic cancer for patients with pancreatitis, especially chronic process. Conclusion: CA 19-9 was a high sensitive and K-ras was a high specific method in diagnosing patients with pancreatic cancer. These two modalities probably act different roles during different conditions in diagnosing pancreatic carcinoma.
PMCID: PMC4238530  PMID: 25419353
Carbohydrate antigen 19-9; K-ras mutation; pancreatic carcinoma; diagnosis; meta-analysis
22.  Arginine methylation-dependent reader-writer interplay governs growth control by E2F-1 
Molecular cell  2013;52(1):37-51.
Summary
The mechanisms that underlie and dictate the different biological outcomes of E2F-1 activity have yet to be elucidated. We describe the residue-specific methylation of E2F-1 by the asymmetric dimethylating protein arginine methyltransferase (PRMT) 1 and symmetric dimethylating PRMT5, and relate the marks to different functional consequences of E2F-1 activity. Methylation by PRMT1 hinders methylation by PRMT5, which augments E2F-1-dependent apoptosis, whereas PRMT5-dependent methylation favours proliferation by antagonising methylation by PRMT1. The ability of E2F-1 to prompt apoptosis in DNA damaged cells coincides with enhanced PRMT1 methylation. In contrast, cyclin A binding to E2F-1 impedes PRMT1 methylation and augments PRMT5 methylation, thus ensuring that E2F-1 is locked into its cell cycle progression mode. The Tudor domain protein p100-TSN reads the symmetric methylation mark, and binding of p100-TSN down-regulates E2F-1 apoptotic activity. Our results define an exquisite level of precision in the reader-writer interplay that governs the biological outcome of E2F-1 activity.
doi:10.1016/j.molcel.2013.08.039
PMCID: PMC4129656  PMID: 24076217
23.  Factorial study of moxibustion in treatment of diarrhea-predominant irritable bowel syndrome 
World Journal of Gastroenterology : WJG  2014;20(37):13563-13572.
AIM: To identify an appropriate therapeutic regimen for using aconite cake-separated moxibustion to treat diarrhea-predominant irritable bowel syndrome (D-IBS).
METHODS: A factorial design was employed to examine the two factors of moxibustion frequency and number of cones. The two tested frequencies were three or six moxibustion sessions per week, and the two tested doses were one or two cones per treatment. A total of 166 D-IBS patients were randomly divided into four treatment groups, which included each combination of the examined frequencies and doses. The bilateral Tianshu acupoints (ST25) and the Qihai acupoint (RN6) were selected for aconite cake-separated moxibustion. Each patient received two courses of treatment, and each course had a duration of 2 wk. For each group, the scores on the Birmingham irritable bowel syndrome (IBS) symptom questionnaire, the IBS Quality of Life scale, the Self-Rating Depression Scale (SDS), the Self-Rating Anxiety Scale (SAS), the Hamilton Depression (HAMD) scale, and the Hamilton Anxiety (HAMA) scale were determined before treatment, after the first course of treatment, and after the second course of treatment.
RESULTS: The symptom, quality of life, SDS, SAS, HAMD, and HAMA scores of the patients in all 4 aconite cake-separated moxibustion groups were significantly lower after the first and second courses of treatment than before treatment (P < 0.001 for all). The symptom, quality of life, SDS, SAS, HAMD, and HAMA scores of the patients in all four aconite cake-separated moxibustion groups were significantly lower after the second course of treatment than after the first course of treatment (P < 0.001 for all). Between-group comparisons after the second course of treatment revealed that the symptom scores for group 1 (1 cone, 3 treatments/wk) and group 3 (2 cones, 3 treatments/wk) were significantly lower than that for group 2 (1 cone, 6 treatments/wk) (5.55 ± 5.05 vs 10.45 ± 6.61, P < 0.001; 5.65 ± 4.00 vs 10.45 ± 6.61, P < 0.001). Regarding the two levels of the two examined factors for aconite cake-separated moxibustion, after the first course of treatment, the changes in HAMA scores were significantly different for the two tested moxibustion frequencies (P = 0.011), with greater changes for the “6 treatments/wk” groups than for the “3 treatments/wk” groups; in addition, there were interaction effects between the number of cones and moxibustion frequency (P = 0.028). After the second course of treatment, changes in symptom scores for the 2 tested moxibustion frequencies were significantly different (P = 0.002), with greater changes for the “3 treatments/wk” groups than for the “6 treatments/wk” groups.
CONCLUSION: An aconite cake-separated moxibustion treatment regimen of 3 treatments/wk and 1 cone/treatment appears to produce better therapeutic effects for D-IBS compared with the other tested regimens.
doi:10.3748/wjg.v20.i37.13563
PMCID: PMC4188908  PMID: 25309087
Diarrhea-predominant irritable bowel syndrome; Aconite cake-separated moxibustion; Factorial design; Moxibustion quantity; Clinical research
24.  Study of ZHENG differentiation in Hepatitis B-caused cirrhosis: a transcriptional profiling analysis 
Background
In traditional Chinese medicine (TCM) clinical practice, ZHENG (also known as TCM syndrome) helps to understand the human homeostasis and guide individualized treatment. However, the scientific basis of ZHENG remains unclear due to limitations of current reductionist approaches.
Methods
We collected the leukocyte samples of three hepatitis B-caused cirrhosis (HBC) patients with dampness-heat accumulation syndrome (DHAS) and three HBC patients with liver depression and spleen deficiency syndrome (LDSDS) for microarray analysis. We generated Gene-Regulatory-Networks (GeneRelNet) from the differentially expressed genes (DEGs) of microarray date. Core genes were validated using anther independent cohort of 40 HBC patients (20 DHAS, 20 LDSDS) with RT-PCR.
Results
There were 2457 mapped genes were differentially expressed between DHAS and LDSDS (Fold change ≥ 2.0, P < 0.05). There were markedly different genes co-expression patterns in DHAS and LDSDS. Furthermore, three differential co-expression genes including purine nucleoside phosphorylase (PNP); aquaporin 7 (AQP7) and proteasome 26S subunit, non-ATPase 2 (PSMD2) were screened by GeneRelNets, and their mRNA expressions were further validated by real time RT-PCR. The results were consistent with microarray. The PNP (P = 0.007), AQP7 (P = 0.038) and PSMD2 (P = 0.009) mRNA expression is significant difference between DHAS and LDSDS using the non-parametric test. Furthermore, we constructed an mRNA panel of PNP, AQP7 and PSMD2 (PAP panel) by logistic regression model, and evaluated the PAP panel to distinguish DHAS from LDSDS by area under the receiver operating characteristic curve (AUC) analysis, which showed a higher accuracy (AUC = 0.835). Gene ontology (GO) analysis indicated that the DHAS is most likely related to system process while the functions overrepresented by LDSDS most related to the response to stimulus.
Conclusions
This study suggested that there are particular transcriptional profiles, genes co-expressions patterns and functional properties of DHAS and LDSDS, and PNP, AQP7, and PSMD2 may be involved in ZHENG differentiation of DHAS and LDSDS in HBC.
Electronic supplementary material
The online version of this article (doi:10.1186/1472-6882-14-371) contains supplementary material, which is available to authorized users.
doi:10.1186/1472-6882-14-371
PMCID: PMC4192401  PMID: 25280538
ZHENG differentiation; Transcriptional profiling; Differentially expressed genes; Gene co-expression; Hepatitis B-caused cirrhosis
25.  A novel partner of Scalloped regulates Hippo signaling via antagonizing Scalloped-Yorkie activity 
Cell Research  2013;23(10):1201-1214.
The Hippo (Hpo) pathway controls tissue growth and organ size by regulating the activity of transcriptional co-activator Yorkie (Yki), which associates with transcription factor Scalloped (Sd) in the nucleus to promote downstream target gene expression. Here we identify a novel protein Sd-Binding-Protein (SdBP)/Tgi, which directly competes with Yki for binding to Sd through its TDU domains and inhibits the Sd-Yki transcriptional activity. We also find that SdBP retains Yki in the nucleus through the association with Yki WW domains via its PPXY motifs. Collectively, we identify SdBP as a novel component of the Hpo pathway, negatively regulating the transcriptional activity of Sd-Yki to restrict tissue growth.
doi:10.1038/cr.2013.120
PMCID: PMC3790236  PMID: 23999857
Hippo; Sd

Results 1-25 (283)