High-resolution and multi-range particle separation by microscopic vibration in an optofluidic chip

An optofluidic chip is demonstrated in experiments for high-resolution and multi-range particle separation through the optically-induced microscopic vibration effect, where nanoparticles are trapped in loosely overdamped optical potential wells created with combined optical and fluidic constraints. It is the first demonstration of separating single nanoparticles with diameters ranging from 60 to 100 nm with a resolution of 10 nm. Nanoparticles vibrate with an amplitude of 3-7 μm in the loosely overdamped potential wells in the microchannel. The proposed optofluidic device is capable of high-resolution particle separation at both nanoscale and microscale without reconfiguring the device. The separation of bacteria from other larger cells is accomplished using the same chip and operation conditions. The unique trapping mechanism and the superb performance in high-resolution and multi-range particle separation of the proposed optofluidic chip promise great potential for a diverse range of biomedical applications.

Comparative transcriptomic analysis of key genes involved in flavonoid biosynthetic pathway and identification of a flavonol synthase from Artemisia annua L

The regulatory mechanism of flavonoids, which synergise anti-malarial and anti-cancer compounds in Artemisia annua, is still unclear. In this study, an anthocyanidin-accumulating mutant callus was induced from A. annua and comparative transcriptomic analysis of wild-type and mutant calli performed, based on the next-generation Illumina/Solexa sequencing platform and de novo assembly. A total of 82,393 unigenes were obtained and 34,764 unigenes were annotated in the public database. Among these, 87 unigenes were assigned to 14 structural genes involved in the flavonoid biosynthetic pathway and 37 unigenes were assigned to 17 structural genes related to metabolism of flavonoids. More than 30 unigenes were assigned to regulatory genes, including R2R3-MYB, bHLH and WD40, which might regulate flavonoid biosynthesis. A further 29 unigenes encoding flavonoid biosynthetic enzymes or transcription factors were up-regulated in the mutant, while 19 unigenes were down-regulated, compared with the wild type. Expression levels of nine genes involved in the flavonoid pathway were compared using semi-quantitative RT-PCR, and results were consistent with comparative transcriptomic analysis. Finally, a putative flavonol synthase gene (AaFLS1) was identified from enzyme assay in vitro and in vivo through heterogeneous expression, and confirmed comparative transcriptomic analysis of wild-type and mutant callus. The present work has provided important target genes for the regulation of flavonoid biosynthesis in A. annua.

[Study of long non-coding RNA HOTAIR expression in middle ear cholesteatoma]

Objective:To discuss the different expression of some long-chain noncoding RNA between middle ear cholesteatoma epithelial tissue and normal external ear canal skin.Method:Real-time quantitative PCR was used to detect the expression of 6 kinds of lncRNA: HOTAIR, ANCR, TINCR, PRINS, BANCR, PICSAR in 25 cases of cholesteatoma epithelial tissues and 15 cases of normal external auditory canal skin tissue samples, respectively. And compared the expression level of lncRNA in patients with different degree of bone destruction.Result:Expression level of HOTAIR was significantly increased in cholesteatoma epithelial tissues compared with the normal external auditory canal skin tissues,and the difference is statistically significant (P< 0.01). While there was no statistically significant difference expression of the rest of the five kinds of lncRNA between middle ear cholesteatoma epithelial tissues and normal external ear canal skin (P> 0.05). And there was no statistically significant difference expression of HOTAIR in patients with different degree of bone destruction (P> 0.05).Conclusion:Expression level of HOTAIR was up-regulated in middle ear cholesteatoma epithelial tissue compared with the normal external auditory canal skin tissues, and the expression level of HOTAIR has no obvious correlation with degree of bone destruction in patients with cholesteatoma.

Post-directed-self-assembly membrane fabrication for in situ analysis of block copolymer structures

Full characterization of the three-dimensional structures resulting from the directed self-assembly (DSA) of block copolymers (BCP) remains a difficult challenge. Transmission electron microscope (TEM) tomography and resonant soft x-ray scattering have emerged as powerful and complementary methods for through-film characterization; both techniques require samples to be prepared on specialized membrane substrates. Here we report a generalizable process to implement BCP DSA with density multiplication on silicon nitride membranes. A key feature of the process developed here is that it does not introduce any artefacts or damage to the polymer assemblies as DSA is performed prior to back-etched membrane formation. Because most research and applications of BCP lithography are based on silicon substrates, process variations introduced by implementing DSA on a silicon nitride/silicon stack versus silicon were identified and mitigated. Using full-wafers, membranes were fabricated with different sizes and layouts to enable both TEM and x-ray characterization. Finally, both techniques were used to characterize structures resulting from the DSA of lamella-forming BCP with density multiplication.

[The progress of stem cells in the treatment of olfactory dysfunction]

Olfactory dysfunction is one of the common diseases in the Department of Otorhinolaryngology. Although the olfactory nerve has ability to regenerate in human central nervous system, if the damage involves nerve, only a few patients can restore the olfactory function. At present, there is no satisfactory treatment for sensorineural olfactory dysfunction. Therefore, it is urgent to explore new and effective method for treating sensorineural olfactory dysfunction. The progress of stem cells in the treatment of olfactory dysfunction is reviewed in this article.

Abstract P3-03-03: A mouse model of sporadic breast tumor with a conditional P53 mutation

Missense mutations in the tumor suppressor gene p53 are present in more than 50% of human tumors. In particular, the arginine-to-histidine mutation at codon 175 (p53R175H) has been found in more than 4% of human breast cancers. p53 mutations fall into two general categories: germline mutations that are associated with hereditary tumors, and somatic mutations that cause sporadic tumors. Mouse models for cancers induced by p53 germline mutations have been established and characterized. However, hitherto there are no accurate animal models for sporadic tumors induced by p53 somatic missense mutations, although this mechanism of inactivating p53 occurs in a large fraction of human cancers.

We have generated a mouse allele, p53WM, that carries coding sequences for both wild type (WT) and R172H mutant p53 (corresponding to R175H in humans) at the p53 endogenous locus. The coding sequence for WT p53 is flanked by loxP sites and therefore can be deleted by Cre recombinase. In the absence of Cre, following radiation, the p53WM/+ mice have the similar ability as the p53 WT mice to activate p53, as demonstrated by transcriptional activation of p53 targets and induction of apoptosis. In addition, like WT mouse embryonic fibroblasts (MEFs), the p53WM/+ MEFs also underwent cell cycle arrest following radiation. After crossing p53WM/+ mice with Zp3-Cre mice which express the Cre recombinase in oocytes, the coding sequence for WT p53 was removed, and the mutant p53R172H allele was regenerated as determined by sequencing, western blot analysis and real time reverse transcription PCR.

To investigate whether a somatic p53R172H mutation in mammary epithelium can induce breast tumors, adenoviruses expressing Cre (Ad-Cre) were injected into the mammary duct of p53WM/+ mice. Limiting the adenovirus dose allowed us to induce the p53R172H mutation in 1 of 20, 100 or 1000 cells, generating a mutant p53 surrounded by normal cells which more accurately mimics the clinical situation of sporadic tumors. Meanwhile, p53WM/+; K14-Cre and p53WM/+; WAP-Cre mice have been generated, in which p53R172H mutation are induced through Cre transgene specifically in the mammary epithelial cells. Lastly, to examine how somatic p53 mutation cooperates with an oncogene in mammary tumor induction, MMTV-neu; p53WM/+ mice were also subjected to the mammary intraductal Ad-Cre injection. We are currently monitoring mice and will further investigate the molecular mechanisms of tumorigenesis by studying the loss of heterozygosity, and the co-evolution of tumor epithelial cells and their microenvironment. This mouse model is more likely to share the underlying molecular pathology with human sporadic tumors. Therefore, it will be more predictive of human responses to drugs, and thus a more valuable tool in preclinical testing.

Citation Format: Zhang Y, Xiong S, Pant V, El-Naggar A, Lozano G. A mouse model of sporadic breast tumor with a conditional P53 mutation. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-03-03.

Epigallocatechin-3-gallate opposes HBV-induced incomplete autophagy by enhancing lysosomal acidification, which is unfavorable for HBV replication

Epigallocatechin-3-gallate (EGCG), a major polyphenol in green tea, exhibits diverse beneficial properties, including antiviral activity. Autophagy is a cellular process that is involved in the degradation of long-lived proteins and damaged organelles. Recent evidence indicates that modulation of autophagy is a potential therapeutic strategy for various viral diseases. In the present study, we investigated the effect of EGCG on hepatitis B virus (HBV) replication and the possible involvement of autophagy in this process. Our results showed that HBV induced autophagosome formation, which was required for replication of itself. However, although EGCG efficiently inhibited HBV replication, it enhanced, but not inhibited, autophagosome formation in hepatoma cells. Further study showed that HBV induced an incomplete autophagy, while EGCG, similar to starvation, was able to induce a complete autophagic process, which appeared to be unfavorable for HBV replication. Furthermore, it was found that HBV induced an incomplete autophagy by impairing lysosomal acidification, while it lost this ability in the presence of EGCG. Taken together, these data demonstrated that EGCG treatment opposed HBV-induced incomplete autophagy via enhancing lysosomal acidification, which was unfavorable for HBV replication.

Water's tensile strength measured using an optofluidic chip

In this paper, for the first time, the tensile strength of water is directly measured using an optofluidic chip based on the displacement of air-water interface deformation with homogeneous nucleation. When water in a microchannel is stretched dynamically via laser-induced shock reflection at the air-water interface, the shock pressures are determined by measuring the displacements of the deformed interface. Observation of the vapor bubbles is used as a probe to identify the cavitation threshold with a critical distance, and the tensile strength of water at 20 °C is measured to be -33.3 ± 2.8 MPa. This method can be extended to investigate the tensile strength of other soft materials such as glycerol, which is measured to be -59.8 ± 10.7 MPa at 20 °C.

MDM4/HIPK2/p53 cytoplasmic assembly uncovers coordinated repression of molecules with anti-apoptotic activity during early DNA damage response

The p53 inhibitor, MDM4 (MDMX) is a cytoplasmic protein with p53-activating function under DNA damage conditions. Particularly, MDM4 promotes phosphorylation of p53 at Ser46, a modification that precedes different p53 activities. We investigated the mechanism by which MDM4 promotes this p53 modification and its consequences in untransformed mammary epithelial cells and tissues. In response to severe DNA damage, MDM4 stimulates p53Ser46^P by binding and stabilizing serine–threonine kinase HIPK2. Under these conditions, the p53-inhibitory complex, MDM4/MDM2, dissociates and this allows MDM4 to promote p53/HIPK2 functional interaction. Comparative proteomic analysis of DNA damage-treated cells versus -untreated cells evidenced a diffuse downregulation of proteins with anti-apoptotic activity, some of which were targets of p53Ser46^P/HIPK2 repressive activity. Importantly, MDM4 depletion abolishes the downregulation of these proteins indicating the requirement of MDM4 to promote p53-mediated transcriptional repression. Consistently, MDM4-mediated HIPK2/p53 activation precedes HIPK2/p53 nuclear translocation and activity. Noteworthy, repression of these proteins was evident also in mammary glands of mice subjected to γ-irradiation and was significantly enhanced in transgenic mice overexpressing MDM4. This study evidences the flexibility of MDM2/MDM4 heterodimer, which allows the development of a positive activity of cytoplasmic MDM4 towards p53-mediated transcriptional function. Noteworthy, this activity uncovers coordinated repression of molecules with shared anti-apoptotic function which precedes active cell apoptosis and that are frequently overexpressed and/or markers of tumour phenotype in human cancer.

Droplet generation via a single bubble transformation in a nanofluidic channel

Here we report the first demonstration on droplet generation from the transformation of a single bubble in a nanofluidic channel by a laser-induced jet. A viscous two-dimensional Rayleigh-Plesset-type model is derived to describe the bubble dynamics in the nanofluidic channel, which accounts for the effect of shear stresses from the channel wall. The droplet generation (number and volume) is investigated experimentally by controlling the jet velocity via laser energy and distance. This study expands the understanding of jetting in the nanofluidic channel and demonstrates a novel method for femtoliter-volume single or multiple droplet formation. It is envisioned that this work will open new doors in on-demand generation of nanodroplets.

Altered intrinsic regional activity and corresponding brain pathways reflect the symptom severity of functional dyspepsia

BACKGROUND

Increasing evidence shows central abnormalities in functional dyspepsia (FD) patients, but whether the symptom severity is directly reflected in altered brain patterns remains unclear. The purpose of this study was to explore how FD affected the resting functional brain patterns for different degrees of symptom severity.

METHODS

Functional magnetic resonance imaging was carried out in 40 FD patients and 20 healthy controls. The resting-state brain changes in regional homogeneity (ReHo) and seed correlation analysis were investigated in patients relative to controls. To what degree the brain changes reflected the severity of the disease was assessed by a pattern classification technique.

KEY RESULTS

Altered ReHo values (p < 0.05, FDR corrected) were discovered in multiple brain areas in FD patients, and only the anterior cingulate cortex (ACC) and thalamus exhibited significant correlation with the severity of dyspepsia symptoms. Compared with controls, the neural signal changes of the thalamus were not found in the less severe FD patient group but in the relatively more severe group, while the ACC showed aberrations in both groups. Seed-based correlation analysis revealed ACC- and thalamus-related functional connectivity differences between FD patients and controls at a voxel-wise level, and the altered thalamic circuits provided the best performance in distinguishing FD patients with different levels of symptom severity.

CONCLUSIONS & INFERENCES

Our results indicated that the functional abnormalities of the ACC and thalamus may occur at different clinical courses in FD. This may help us better understand the progression of FD.

PA28gamma emerges as a novel functional target of tumour suppressor microRNA-7 in non-small-cell lung cancer

BACKGROUND

MicroRNA-7 (miR-7) has been reported to be a tumour suppressor gene. However, whether it has a role in the growth of non-small-cell lung cancer (NSCLC) and what is its target involved in the tumour growth is still under investigation.

METHODS

NSCLC tissue sample, NSCLC cell lines and tissue microarray were investigated in this study. Total RNA, miRNA and protein were used for RT-PCR and western blot analysis. Immunohistochemistry was performed in tissues microarray. Cell culture and intervention experiments were performed in vitro and in vivo. Bioinformatics prediction, western blot and luciferase assay were identified the target of miR-7.

RESULTS

In this study, we found that the expression of miR-7 was significantly downregulated not only in NSCLC cell lines, but also in human NSCLC tissues compared with the matched adjacent tissues. Restoration of its expression through miR-7 mimics in A549 and H1299 NSCLC cells inhibited cell proliferation, colony formation, and cell-cycle progression in vitro. More importantly, the tumorigenicity in nude mice was reduced after administration of miR-7 in vivo. In advance, through bioinformatic analysis, luciferase assay and western blot, we identified a novel target of miR-7, PA28gamma (a proteasome activator) to be enrolled in the regulation with tumour. PA28gamma mRNA and protein levels are markedly upregulated in NSCLC cell lines and tumour samples, exhibiting a strong inverse relation with that of miR-7. In addition, knockdown of PA28gamma induced similar effects as overexpression of miR-7 in NSCLC cells. Furthermore, miR-7 overexpression or silencing of PA28gamma reduced the cyclinD1 expression at mRNA and protein level in NSCLC cell lines.

CONCLUSION

All these findings strongly imply that the overexpression of PA28gamma resulted from miR-7 downexpression in NSCLC has an important role in promoting cancer cell progress and consequently results in NSCLC growth. Thus, strategies targeting PA28gamma and/or miR-7 may become promising molecular therapies in NSCLC treatment.

Monitoring wound healing of elastic cartilage using multiphoton microscopy

OBJECTIVE

To demonstrate the ability of multiphoton microscopy (MPM) for monitoring wound healing of elastic cartilage.

METHOD

In a rabbit ear model, four cartilage specimen groups at 1-day, 1-, 4-, 20-week healing time points as well as a normal elastic cartilage were examined with MPM without using labeling agents. MPM images at wound margins were obtained from specimens at different healing stages, compared with the Hematoxylin and Eosin (H&E) stained images. Image analysis was performed to characterize the collagen morphology for quantifying the wound healing progression of elastic cartilage.

RESULTS

MPM provided high-resolution images of elastic cartilage at varying depths. Comparisons of the images of specimens at different healing stages show obvious cell growth and matrix deposition. The results are consistent with the histological results. Moreover, quantitative analysis results show significant alteration in the collagen cavity size or collagen orientation index during wound healing of elastic cartilage, indicating the possibility to act as indicators for monitoring wound healing.

CONCLUSION

Our results suggested that MPM has the ability to monitor the wound healing progression of elastic cartilage, based on the visualization of cell growth and proliferation and quantitative characterization of collagen morphology during wound healing.