The neuroprotective role and mechanisms of TERT in neurons with oxygen-glucose deprivation

Telomerase reverse transcriptase (TERT) is reported to protect neurons from apoptosis induced by various stresses including hypoxia-ischemia (HI). However, the mechanisms by which TERT exerts its anti-apoptotic role in neurons with HI injury remain unclear. In this study, we examined the protective role and explored the possible mechanisms of TERT in neurons with HI injury in vitro. Primary cultured neurons were exposed to oxygen and glucose deprivation (OGD) for 3h followed by reperfusion to mimic HI injury in vivo. Plasmids containing TERT antisense, sense nucleotides, or mock were transduced into neurons at 48h before OGD. Expression and distribution of TERT were measured by immunofluorescence labeling and western blot. The expression of cleaved caspase 3 (CC3), Bcl-2 and Bax were detected by western blot. Neuronal apoptosis was measured with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). The mitochondrial reactive oxygen species (ROS) were measured by MitoSOX Red staining. Fluorescent probe JC-1 was used to measure the mitochondrial membrane potential (ΔΨm). We found that TERT expression increased at 8h and peaked at 24h in neurons after OGD. CC3 expression and neuronal apoptosis were induced and peaked at 24h after OGD. TERT inhibition significantly increased CC3 expression and neuronal apoptosis after OGD treatment. Additionally, TERT inhibition decreased the expression ratio of Bcl-2/Bax, and enhanced ROS production and ΔΨm dissipation after OGD. These data suggest that TERT plays a neuroprotective role via anti-apoptosis in neurons after OGD. The underlying mechanisms may be associated with regulating Bcl-2/Bax expression ratio, attenuating ROS generation, and increasing mitochondrial membrane potential.

Skeletal muscle evaluation by MRI in a rabbit model of acute ischaemia

OBJECTIVE

To assess rhabdomyolysis-associated skeletal muscle changes induced by complete ischaemia in rabbits using MRI.

METHODS

Acute ischaemia was induced in the right hind limb of 34 New Zealand white rabbits by arterial ligation. MRI of vastus lateralis was carried out pre-operatively and every hour post-operatively up to 7 h. T1 weighted images, T2 weighted images with fat suppression, T2 maps and diffusion tensor scans were obtained. The correlation of MRI findings with histopathological changes in biopsies of vastus lateralis was examined.

RESULTS

Histopathology demonstrated early cellular oedema 1 h post ischaemia and irreversible injuries by 7 h, including loss of striation and broken muscle fibres. T2 weighted images with fat suppression showed inhomogeneous high signal intensity of vastus lateralis, which progressively increased from 2 h following ischaemia. The T2 relaxation rate of ischaemic vastus lateralis was significantly greater than normal muscle (p<0.001) and demonstrated a linear increase with time following ischaemia. A similar linear increase was also found in the ischaemic vastus lateralis apparent diffusion coefficient (ADC) 1-5 h post ischaemia (p=0.006). Both the T2 ADC and fractional anisotropy (FA) were significantly higher on the ischaemic side 7 h post ischaemia (for T2, p=0.02; for ADC, p=0.004).

CONCLUSION

Muscle oedema is detectable on MR images and is reflected well by T2, ADC and FA values. MRI may have value in clinical evaluation of rhabdomyolysis.

ADVANCES IN KNOWLEDGE

Ischaemic changes detected by MRI may have value in the diagnosis of rhabdomyolysis.

RNA interference suppression of A100A4 reduces the growth and metastatic phenotype of human renal cancer cells via NF-kB-dependent MMP-2 and bcl-2 pathway

BACKGROUND AND AIM

S100A4 is a well established marker and mediator of metastatic disease, but the exact mechanisms responsible for the metastasis promoting effects are less well defined. We tested a hypothesis that the S100A4 gene plays a role in the proliferation and invasiveness of human renal cancer cells (RCC) and may be associated with its metastatic spread.

MATERIALS AND METHODS

The small interference RNA vector pcDNA3.1-S100A4 siRNA was transfected in to the human renal cancer cell lines ACHN, Ketr-3, OS-RC-2, CaKi-2 and HTB-47, then treated with ABT-737 or BB94. Cell apoptosis and cell viability was detected by flow cytometry and MTT assay. Matrigel was used for cell motility and invasion assay. MMP-2, bcl-2 and S100A4 was detected by RT-PCR and western blot assay. NF-kB subunit p65 activity was detected by confocal microscopy assay. We then determine the effect S100A4 sliencing on tumor growth, lung metastasis development in vivo. Immunohistochemistry was used to detected the expression of S100A4, bcl-2, MMP-2, p65 and CD31.

RESULTS

S100A4 silencing in ACHN cells by RNA interference significantly inhibited NF-kB and NF-kB-mediated MMP-2 and bcl-2 activation and cellular migration, proliferation, and promoted apoptosis. Furthermore, re-expression of S100A4 in S100A4-siRNA-transfected ACHN cells by transient S100A4 cDNA transfection restored the NF-kB and NF-kB-mediated MMP-2 and bcl-2 activation and their high migratory and cellular proliferative ability. An inhibitor ABT-737 (the Bcl-2 antagonist targets Bcl-2) against Bcl-2 suppressed cellular proliferation and promoted apoptosis induced by S100A4 re-expression in S100A4-siRNA-transfected ACHN cells. A inhibitor BB94 against MMPs to neutralize MMP-2 protein suppressed cellular invasion and migration induced by S100A4 re-expression in S100A4-siRNA-transfected ACHN cells. In the prevention model, S100A4 silencing inhibited primary tumor growth by (tumor weight) (76 ± 8%) and (tumor volum) (78 ± 4%) respectively and promoted apoptosis and the formation of lung metastases was inhibited by 89% (p < 0.01). Microvascular density was reduced by 70% (p < 0.01). In addition, S100A4 sliencing inhibited the expression of S100A4 in vivo, followed by the NF-kB, MMP-2 and bcl-2 suppression.

CONCLUSIONS

We conclude that S100A4 plays a crucial role in proliferation and migratory/invasive processes in human RCC by a mechanism involving activation of NF-kB-bcl-2 and NF-kB-MMP-2 pathway.

Novel EDA p.Ile260Ser mutation linked to non-syndromic hypodontia

Hypodontia, a tooth developmental disease, can affect chewing and pronunciation. Mutations in the ectodysplasin-A (EDA) gene can lead to both X-linked hypohidrotic ectodermal dysplasia (XLHED) and non-syndromic hypodontia (NSH). However, the mechanism by which these 2 related but different disorders are caused by the distinct mutations in EDA is unknown. In this study, we identified a novel missense mutation (c.779 T>G) in a Chinese family with NSH via a direct sequencing approach. This mutation results in an Ile260Ser substitution in the tumor necrosis factor (TNF) homology domain. Homology modeling suggests that this alteration may induce a conformational change in the hydrophobic center of the TNF homology domain. Furthermore, by exploring systematic 3D conformation analysis and calculation of residue relative solvent accessibility (RSA) for all the reported mutated amino acid sites on EDA's TNF homology domain, we found that the site mutations at the interior may be linked to XLHED, while those at the surface are more likely to be associated with NSH. These findings may aid in the discovery of unidentified functionally significant mutation sites in the EDA gene and provide a new way to clarify the mechanisms by which the XLHED and NSH phenotypes arise from mutations in the same gene.

An analysis of FMA using structural self-bisimilarity

As ontologies are mostly manually created, they tend to contain errors and inconsistencies. In this paper, we present an automated computational method to audit symmetric concepts in ontologies by leveraging self-bisimilarity and linguistic structure in the concept names. Two concepts A and B are symmetric if concept B can be obtained from concept A by replacing a single modifier such as "left" with its symmetric modifier such as "right." All possible local structural types for symmetric concept pairs are enumerated according to their local subsumption hierarchy, and the pairs are further classified into Non-Matches and Matches. To test the feasibility and validate the benefits of this method, we computed all the symmetric modifier pairs in the Foundational Model of Anatomy (FMA) and selected six of them for experimentation. 9893 Non-Matches and 221 abnormal Matches with potential errors were discovered by our algorithm. Manual evaluation by FMA domain experts on 176 selected Non-Matches and all the 221 abnormal Matches found 102 missing concepts and 40 misaligned concepts. Corrections for them have currently been implemented in the latest version of FMA. Our result demonstrates that self-bisimilarity can be a valuable method for ontology quality assurance, particularly in uncovering missing concepts and misaligned concepts. Our approach is computationally scalable and can be applied to other ontologies that are rich in symmetric concepts.

Dissecting the Ambiguity of FMA Concept Names Using Taxonomy and Partonomy Structural Information

The complex inner structures of concept names in the Foundational Model of Anatomy (FMA) remain an obstacle for further analyzing the ontology using lexical methods. A very common problem is the ambiguity lying in names with the sometimes multiple occurrences of the preposition "of." In this paper, we propose an automatic method to help disambiguating FMA terms by leveraging the taxonomy and partonomy information. If a sub-phrase of a concept name also appears in its parents, it is likely to occur as a sub-tree in its parse tree, hence should be parsed as such. We classified all the concept names with a single occurrence of the preposition "of" by the appearances of their sub-phrases in the parent names using three test suites. Results show that more than 90% of them can be provided with useful information to assist their correct parsing.

Abstract P2-09-06: The structure design and biological activities of inhibitory peptides, which block the interactions among polycomb repressive complex 2

Polycomb repressive complex (PRC2) contains several proteins, including embryonic ectoderm development (EED), suppressor of zeste 12 (SUZ12) and enhancer of zeste homolog 2 (EZH2). Excessive EZH2 concentrations have been reported as a marker of aggressive breast cancer and associated with invasion and cancer progression. EZH2 levels were elevated in patients with invasive breast carcinoma relative to normal or atypical hyperplasia. Except for the C-terminal SET domain, which functions as a histone-lysine N-methyltransferases, EZH2 has an N-terminal alpha helix region, which forms tight complex with EED protein. The in vivo enzymatic activity of EZH2 relies on and be tightly regulated by the interaction with EED. We designed series of artificial peptides trying to block the interaction between EZH2 and EED. By using label-free surface plasmon resonance (SPR) technology, the dynamic binding capacities of these peptides were tested. There were 3 leading structures standing out from the screening of more 80 peptides. After several round of co-crystal structure based optimization, the binding capacity of one inhibitor was reached to several nM levels, which indicated the availability for being a drug candidate. Finally, the biological activities of the inhibitory peptides were tested in several breast cancer cell lines. The PRC2 inhibitory peptides in this study are the first time reported PRC2 targeting epigenetic molecules with biological activity in breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-09-06.

320-detector row CT angiography for detection and evaluation of intracranial aneurysms: comparison with conventional digital subtraction angiography

AIM

To compare the diagnostic performance of 320-detector row computed tomographic angiography (CTA) with digital subtraction angiography (DSA) for the detection and characterization of intracranial aneurysms.

MATERIALS AND METHODS

Fifty-two consecutive patients with non-traumatic subarachnoid haemorrhage (SAH) and suspected intracranial aneurysms were evaluated from January 2009 to October 2011. All underwent both 320-detector row volume CTA examination and DSA. CTA volume data were transmitted to a VITREA workstation and two physicians with experience in diagnostic imaging of the nervous system independently carried out image post-processing and assessed the results. The three-dimensional (3D) CTA and DSA images were assessed using intraoperative findings as the reference standard.

RESULTS

In 52 patients, 54 aneurysms were detected; 48 patients underwent surgery for 50 aneurysms. The overall sensitivity, specificity, and accuracy of 3D CTA were 96.3, 100, and 94.6%, respectively. Meanwhile, the overall sensitivity, specificity, and accuracy of DSA were 98.1, 98.1, and 95.1%, respectively. For aneurysms less than 3 mm, the sensitivity, specificity, and accuracy of 3D CTA were 81.8, 100, and 93.3%, respectively. The sensitivity, specificity, and accuracy of DSA for small aneurysms were 90.9, 100, and 96.2%, respectively. 3D CTA was superior to DSA in demonstrating aneurysmal calcification, parent artery, and surrounding vascular anatomy.

CONCLUSIONS

3D CTA is a highly sensitive, specific, and non-invasive imaging method for diagnosis and evaluation of intracranial aneurysms. It also allows for precise depiction of aneurysm morphology. Therefore, 320-detector row CTA may be used as an alternative to DSA as a first-line imaging technique in patients with SAH.

OPIC: Ontology-driven Patient Information Capturing system for epilepsy

The widespread use of paper or document-based forms for capturing patient information in various clinical settings, for example in epilepsy centers, is a critical barrier for large-scale, multi-center research studies that require interoperable, consistent, and error-free data collection. This challenge can be addressed by a web-accessible and flexible patient data capture system that is supported by a common terminological system to facilitate data re-usability, sharing, and integration. We present OPIC, an Ontology-driven Patient Information Capture (OPIC) system that uses a domain-specific epilepsy and seizure ontology (EpSO) to (1) support structured entry of multi-modal epilepsy data, (2) proactively ensure quality of data through use of ontology terms in drop-down menus, and (3) identify and index clinically relevant ontology terms in free-text fields to improve accuracy of subsequent analytical queries (e.g. cohort identification). EpSO, modeled using the Web Ontology Language (OWL), conforms to the recommendations of the International League Against Epilepsy (ILAE) classification and terminological commission. OPIC has been developed using agile software engineering methodology for rapid development cycles in close collaboration with domain expert and end users. We report the result from the initial deployment of OPIC at the University Hospitals Case Medical Center (UH CMC) epilepsy monitoring unit (EMU) as part of the NIH-funded project on Sudden Unexpected Death in Epilepsy (SUDEP). Preliminary user evaluation shows that OPIC has achieved its design objectives to be an intuitive patient information capturing system that also reduces the potential for data entry errors and variability in use of epilepsy terms.

An analysis of multi-type relational interactions in FMA using graph motifs with disjointness constraints

The interaction of multiple types of relationships among anatomical classes in the Foundational Model of Anatomy (FMA) can provide inferred information valuable for quality assurance. This paper introduces a method called Motif Checking (MOCH) to study the effects of such multi-relation type interactions for detecting logical inconsistencies as well as other anomalies represented by the motifs. MOCH represents patterns of multi-type interaction as small labeled (with multiple types of edges) sub-graph motifs, whose nodes represent class variables, and labeled edges represent relational types. By representing FMA as an RDF graph and motifs as SPARQL queries, fragments of FMA are automatically obtained as auditing candidates. Leveraging the scalability and reconfigurability of Semantic Web Technology, we performed exhaustive analyses of a variety of labeled sub-graph motifs. The quality assurance feature of MOCH comes from the distinct use of a subset of the edges of the graph motifs as constraints for disjointness, whereby bringing in rule-based flavor to the approach as well. With possible disjointness implied by antonyms, we performed manual inspection of the resulting FMA fragments and tracked down sources of abnormal inferred conclusions (logical inconsistencies), which are amendable for programmatic revision of the FMA. Our results demonstrate that MOCH provides a unique source of valuable information for quality assurance. Since our approach is general, it is applicable to any ontological system with an OWL representation.

A 3D Static Heart Model From a MSCT Data Set

Dynamic Computed Tomography (CT) imaging aims to access the kinetics of the moving organs. In cardiac imaging, the interest lies in the possibility of obtaining anatomic and functional information on the heart and the coronaries during the same examination. However, segmentation, reconstruction and registration algorithms need to be developed for diagnostic purposes. We propose thus to built a 3D heart model from Multi-slice Spiral Computed Tomography (MSCT) dynamic sequences to facilitate the evaluation of these algorithms. The model building relies on semi-automatic segmentation techniques based on deformable models such as Fast Marching and active contours. Shape-based interpolation and Marching Cube algorithms are then used for the 3D surface reconstruction.

Estimation and Removal of Physiological Noise from Undersampled Multi-slice fMRI data in Image Space

The signal variations induced by respiration and cardiac motion decrease the statistical significance in functional MRI data analysis. Significant components of these fluctuations are aliased into the activation spectrum in standard multi-slice imaging protocols. A method of estimation and removal physiological noise in image space is reported. Based on reordering the data from slice ordering to time ordering, the aliased physiological information is available in multi-slice magnitude images. Then physiological noise can be estimated and removed adaptively using signal projecting technique with the actual functional signal preserved.

Femtosecond population inversion and stimulated emission of dense Dirac fermions in graphene

We show that strongly photoexcited graphene monolayers with 35 fs pulses quasi-instantaneously build up a broadband, inverted Dirac fermion population. Optical gain emerges and directly manifests itself via a negative conductivity at the near-infrared region for the first 200 fs, where stimulated emission completely compensates absorption loss in the graphene layer. Our experiment-theory comparison with two distinct electron and hole chemical potentials reproduce absorption saturation and gain at 40 fs, revealing, particularly, the evolution of the transient state from a hot classical gas to a dense quantum fluid with increasing the photoexcitation.

Baculovirus expression and antigenic characterization of classical swine fever virus E2 proteins

Genes encoding a major structural glycoprotein, E2, of classical swine fever viruses (CSFV) Brescia (subgroup 1.2), Paderborn (subgroup 2.1) and Kanagawa (subgroup 3.4) were constructed by removing the transmembrane domain and adding a C-terminal 6 histidine (His) tag. All the E2 constructs were efficiently expressed in a baculovirus system as 53-kDa glycosylated proteins that were identified in Western blots by their reaction with anti-His and CSFV-specific antibodies. These proteins were used as ELISA antigens to confirm the existence of an antigenic relationship between the viruses using group-specific polyclonal antisera. Antigenic differences were identified by Western blot and ELISA reactivity of the E2 proteins with a panel of monoclonal antibodies. Specifically, one monoclonal antibody (WH303) reacted with all three proteins, two monoclonal antibodies (M1660 and M1665) reacted with only the Brescia E2 protein, and three monoclonal antibodies (M1654, M1664 and M1669) reacted equally well with only Brescia and Kanagawa E2 proteins. Therefore, antibody reactivity profiles, established using recombinant E2 proteins, could be used to quickly identify novel CSFV strains as illustrated in this report with only a limited number of monoclonal antibodies. These proteins could also have added utility in the production of monoclonal antibodies and as critical reagents in diagnostic assays.

Efficient doping and energy transfer from ZnO to Eu3+ ions in Eu(3+)-doped ZnO nanocrystals

Successful doping of Eu3+ ions into ZnO nanocrystals has been realized by using a low temperature wet chemical doping technique. The substitution of Eu3+ for Zn2+ is shown to be dominant in the Eu-doped ZnO nanocrystals by analyzing the X-ray diffraction patterns, transmission electron microscopy images, Raman and selectively excited photoluminescence spectra. Measurement of the luminescence from the samples shows that the excited ZnO transfers the excited energy efficiently to the doped Eu3+ ions, giving rise to efficient emission at red spectral region. The red emission quantum yield is measured to be 31% at room temperature. The temperature dependence of photoluminescence and the photoluminescence excitation spectra have also been investigated, showing strong energy coupling between the ZnO host and Eu3+ ions through free and bound excitons. The result indicates that Eu3+ ion-doped ZnO nanocrystals are promising light-conversion materials and have potential application in highly distinguishable emissive flat panel display and LED backlights.