Lysosome triggered near-infrared fluorescence imaging of cellular trafficking processes in real time

Bioresponsive NIR-fluorophores offer the possibility for continual visualization of dynamic cellular processes with added potential for direct translation to in vivo imaging. Here we show the design, synthesis and lysosome-responsive emission properties of a new NIR fluorophore. The NIR fluorescent probe design differs from typical amine functionalized lysosomotropic stains with off/on fluorescence switching controlled by a reversible phenol/phenolate interconversion. Emission from the probe is shown to be highly selective for the lysosomes in co-imaging experiments using a HeLa cell line expressing the lysosomal-associated membrane protein 1 fused to green fluorescent protein. The responsive probe is capable of real-time continuous imaging of fundamental cellular processes such as endocytosis, lysosomal trafficking and efflux in 3D and 4D. The advantage of the NIR emission allows for direct translation to in vivo tumour imaging, which is successfully demonstrated using an MDA-MB-231 subcutaneous tumour model. This bioresponsive NIR fluorophore offers significant potential for use in live cellular and in vivo imaging, for which currently there is a deficit of suitable molecular fluorescent tools.

The synthesis and characterization of 1 1 1 1 type diluted ferromagnetic semiconductor (La(1-x)Ca(x))(Zn(1-x) Mn(x))AsO

We report the synthesis and characterization of a bulk form diluted magnetic semiconductor, (La(1-x)Ca(x))(Zn(1-y) Mn(y))AsO, with a layered crystal structure isostructural to that of the 1 1 1 1 type Fe-based high-temperature superconductor LaFeAsO and the antiferromagnetic LaMnAsO. With Ca and Mn codoping into LaZnAsO, the ferromagnetic ordering occurs below the Curie temperature T(c) ∼30 K. Taking advantage of the decoupled charge and spin doping, we investigate the influence of carrier concentration on the ferromagnetic ordering state. For a fixed Mn concentration of 10%, T(c) increases from 24 K to 30 K when the Ca concentration increases from 5% to 10%. Further increase of Ca concentration reduces both the coercive field and saturation moment. Muon spin relaxation measurements confirm the ferromagnetically ordered state, and clearly demonstrate that La(1-x)Ca(x))(Zn(1-y) Mn(y))AsO shares a common mechanism for the ferromagnetic exchange interaction with (Ga,Mn)As. Neutron scattering measurements show no structural transition in (La(0.90)Ca(0.10))(Zn(0.90)Mn(0.10)) AsO below 300 K.

Strained alkyne substituted near infrared BF2azadipyrromethene fluorochrome

Synthesis and evaluation of a strained alkyne substituted NIR BF₂-azadipyrromethene (NIR-AZA) shows potential for translation to clinical imaging.

Highly efficient chip-scale III-V/silicon hybrid optical amplifiers

We discuss the design and demonstration of highly efficient 1.55 µm hybrid III-V/Silicon semiconductor optical amplifiers (SOA). The optimized III-V wafer stack consists of Al(0.10)In(0.71)Ga(0.18)As multiple quantum wells (MQW) and Al(0.48)In(0.52)As electron stop layers to realize SOAs with high wall-plug efficiency (WPE). We present various designs and experimentally determine WPE values for 2 mW and 0.1 mW input power amplification. The 400 µm long flared SOA achieved the highest WPE value of 12.1% for output power > 10mW and the 400 µm long straight SOA achieved the highest WPE value of 7.3% for output power < 10mW. These are the highest WPE values ever obtained for 1.55 µm SOAs.

Induction of the inflammatory regulator A20 by gibberellic acid in airway epithelial cells

BACKGROUND AND PURPOSE

NF-κB-driven inflammation is negatively regulated by the zinc finger protein A20. Gibberellic acid (GA3 ) is a plant-derived diterpenoid with documented anti-inflammatory activity, which is reported to induce A20-like zinc finger proteins in plants. Here, we sought to investigate the anti-inflammatory effect of GA3 in airway epithelial cells and determine if the anti-inflammatory action relates to A20 induction.

EXPERIMENTAL APPROACH

Primary nasal epithelial cells and a human bronchial epithelial cell line (16HBE14o-) were used. Cells were pre-incubated with GA3 , stimulated with Pseudomonas aeruginosa LPS; IL-6 and IL-8 release, A20, NF-κB and IκBα expression were then evaluated. To determine if any observed anti-inflammatory effect occurred via an A20-dependent mechanism, A20 was silenced using siRNA.

KEY RESULTS

Cells pre-incubated with GA3 had significantly increased levels of A20 mRNA (4 h) and protein (24 h), resulting in a significant reduction in IL-6 and IL-8 release. This effect was mediated via reduced IκBα degradation and reduced NF-κB (p65) expression. Furthermore, the anti-inflammatory action of GA3 was abolished in A20-silenced cells.

CONCLUSIONS AND IMPLICATIONS

We showed that A20 induction by GA3 attenuates inflammation in airway epithelial cells, at least in part through its effect on NF-κB and IκBα. GA3 or gibberellin-derived derivatives could potentially be developed into anti-inflammatory drugs for the treatment of chronic inflammatory diseases associated with A20 dysfunction.

Conservative management of aortic arch injury following penetrating trauma

Aortic arch injuries following penetrating trauma are typically lethal events with high mortality rates. Traditionally, the standard of care for patients presenting with penetrating injury and aortic involvement has included surgical intervention. We report the case of a 31-year-old man who was managed non-operatively after sustaining multiple stab wounds to the left chest and presenting with mid aortic arch injury.

Synthesis and assessment of a maleimide functionalized BF2 azadipyrromethene near-infrared fluorochrome

Aqueous soluble NIR-AZA fluorochrome which undergoes rapid rt bio-conjugations via thiol addition for in vitro and in vivo imaging.

NIR fluorescence labelled carbon nano-onions: synthesis, analysis and cellular imaging

The preparation of novel NIR fluorescent carbon based nanomaterials, consisting of boron difluoride azadipyrromethene fluorophores covalently attached to carbon nano-onions, is demonstrated. In addition, the analysis of the new nanomaterial is presented. The fluorescent nano-derivative properties are customized such that their emission can be reversibly on/off modulated in response to pH, which is demonstrated in solution and in cells. The in vitro imaging of HeLa Kyoto cells is carried out and the cellular uptake of the carbon nano-onion NIR fluorophore conjugates is verified.

Long-range magnetic order in the 5d(2) double perovskite Ba2CaOsO6: comparison with spin-disordered Ba2YReO6

The B-site ordered double perovskite Ba2CaOsO6 was studied by dc magnetic susceptibility, powder neutron diffraction and muon spin relaxation methods. The lattice parameter is a = 8.3619(6) Å at 280 K and cubic symmetry [Formula: see text] is retained to 3.5 K with a = 8.3462(7) Å. Curie-Weiss susceptibility behaviour is observed for T > 100 K and the derived constants are C = 0.3361(3) emu K mol(-1) and ΘCW = -156.2(3) K, in excellent agreement with literature values. This Curie constant is much smaller than the spin-only value of 1.00 emu K mol(-1) for a 5d(2) Os(6+) configuration, indicating a major influence of spin-orbit coupling. Previous studies had detected both susceptibility and heat capacity anomalies near 50 K but no definitive conclusion was drawn concerning the nature of the ground state. While no ordered Os moment could be detected by powder neutron diffraction, muon spin relaxation (µSR) data show clear long-lived oscillations indicative of a continuous transition to long-range magnetic order below TC = 50 K. An estimate of the ordered moment on Os(6+) is ∼ 0.2 μB, based upon a comparison with µSR data for Ba2YRuO6 with a known ordered moment of 2.2 μB. These results are compared with those for isostructural Ba2YReO6 which contains Re(5+), also 5d(2), and has a nearly identical unit cell constant, a = 8.36278(2) Å-a structural doppelgänger. In contrast, Ba2YReO6 shows ΘCW = - 616 K, and a complex spin-disordered and, ultimately, spin-frozen ground state below 50 K, indicating a much higher level of geometric frustration than in Ba2CaOsO6. The results on these 5d(2) systems are compared to recent theory, which predicts a variety of ferromagnetic and antiferromagnetic ground states. In the case of Ba2CaOsO6, our data indicate that a complex four-sublattice magnetic structure is likely. This is in contrast to the spin-disordered ground state in Ba2YReO6, despite a lack of evidence for structural disorder, for which theory currently provides no clear explanation.

The synthesis of neurotensin antagonist SR 48692 for prostate cancer research

An improved synthesis of the molecule SR 48692 is presented and its use as a neurotensin antagonist biological probe for use in cancer research is described. The preparation includes an number of enhanced chemical conversions and strategies to overcome some of the limiting synthetic transformations in the original chemical route.

DCE-MRI biomarkers of tumour heterogeneity predict CRC liver metastasis shrinkage following bevacizumab and FOLFOX-6

BACKGROUND

There is limited evidence that imaging biomarkers can predict subsequent response to therapy. Such prognostic and/or predictive biomarkers would facilitate development of personalised medicine. We hypothesised that pre-treatment measurement of the heterogeneity of tumour vascular enhancement could predict clinical outcome following combination anti-angiogenic and cytotoxic chemotherapy in colorectal cancer (CRC) liver metastases.

METHODS

Ten patients with 26 CRC liver metastases had two dynamic contrast-enhanced MRI (DCE-MRI) examinations before starting first-line bevacizumab and FOLFOX-6. Pre-treatment biomarkers of tumour microvasculature were computed and a regression analysis was performed against the post-treatment change in tumour volume after five cycles of therapy. The ability of the resulting linear model to predict tumour shrinkage was evaluated using leave-one-out validation. Robustness to inter-visit variation was investigated using data from a second baseline scan.

RESULTS

In all, 86% of the variance in post-treatment tumour shrinkage was explained by the median extravascular extracellular volume (v(e)), tumour enhancing fraction (E(F)), and microvascular uniformity (assessed with the fractal measure box dimension, d(0)) (R(2)=0.86, P<0.00005). Other variables, including baseline volume were not statistically significant. Median prediction error was 12%. Equivalent results were obtained from the second scan.

CONCLUSION

Traditional image analyses may over-simplify tumour biology. Measuring microvascular heterogeneity may yield important prognostic and/or predictive biomarkers.