Dynamic reorganization of Eg5 in the mammalian spindle throughout mitosis requires dynein and TPX2

Kinesin-5 is an essential mitotic motor. However, how its spatial-temporal distribution is regulated in mitosis remains poorly understood. We expressed localization and affinity purification-tagged Eg5 from a mouse bacterial artificial chromosome (this construct was called mEg5) and found its distribution to be tightly regulated throughout mitosis. Fluorescence recovery after photobleaching analysis showed rapid Eg5 turnover throughout mitosis, which cannot be accounted for by microtubule turnover. Total internal reflection fluorescence microscopy and high-resolution, single-particle tracking revealed that mEg5 punctae on both astral and midzone microtubules rapidly bind and unbind. mEg5 punctae on midzone microtubules moved transiently both toward and away from spindle poles. In contrast, mEg5 punctae on astral microtubules moved transiently toward microtubule minus ends during early mitosis but switched to plus end-directed motion during anaphase. These observations explain the poleward accumulation of Eg5 in early mitosis and its redistribution in anaphase. Inhibition of dynein blocked mEg5 movement on astral microtubules, whereas depletion of the Eg5-binding protein TPX2 resulted in plus end-directed mEg5 movement. However, motion of Eg5 on midzone microtubules was not altered. Our results reveal differential and precise spatial and temporal regulation of Eg5 in the spindle mediated by dynein and TPX2.

DNA-templated semiconductor nanocrystal growth for controlled DNA packing and gene delivery

DNA-templated semiconductor nanocrystal (SNC) growth represents a facile means to generate bioactive hybrid nanostructures by directly integrating DNA molecules and luminescent SNCs together via a one-step synthesis, which has been applied to biosensing and cell imaging. In this study we for the first time demonstrated that DNA-templated CdS SNC growth could also be used to rationally tune the structures and activities of large DNA molecules. We explored the synergistic effects of nanocrystal growth on the sizes and charges of DNA molecules and demonstrate that the CdS growth-induced DNA packing could be used as a smart gene delivery system. Herein we used DNA plasmids encoding intact enhanced green fluorescence protein (EGFP) genes as templates to grow CdS SNCs and found that the stepwise growth of CdS nanocrystals can spontaneously induce DNA condensation and negative charge shielding in a synergistic manner. The condensed DNA plasmids exhibited efficient cellular uptake and a relative gene transfection efficiency of 32%. The transfection efficiency can be further doubled in the presence of chloroquine. We elucidated that the gene transfection and expression is controlled by reversible DNA packing, where ligand exchange of DNA with intracellular glutathione molecules plays a critical role in the recovery of DNA plasmids for gene expression.

TPX2 regulates the localization and activity of Eg5 in the mammalian mitotic spindle

TPX2 promotes mitotic spindle formation by enhancing Eg5 accumulation on microtubules and limiting motor activity.

Mitotic spindle assembly requires the regulated activity of numerous spindle-associated proteins. In mammalian cells, the Kinesin-5 motor Eg5 interacts with the spindle assembly factor TPX2, but how this interaction contributes to spindle formation and function is not established. Using bacterial artificial chromosome technology, we generated cells expressing TPX2 lacking the Eg5 interaction domain. Spindles in these cells were highly disorganized with multiple spindle poles. The TPX2–Eg5 interaction was required for kinetochore fiber formation and contributed to Eg5 localization to spindle microtubules but not spindle poles. Microinjection of the Eg5-binding domain of TPX2 resulted in spindle elongation, indicating that the interaction of Eg5 with TPX2 reduces motor activity. Consistent with this possibility, we found that TPX2 reduced the velocity of Eg5-dependent microtubule gliding, inhibited microtubule sliding, and resulted in the accumulation of motor on microtubules. These results establish a novel function of TPX2 in regulating the location and activity of the mitotic motor Eg5.

Synthesis and biological evaluation of 3-substituted-indolin-2-one derivatives containing chloropyrrole moieties

Eighteen novel 3-substituted-indolin-2-ones containing chloropyrroles were synthesized and their biological activities were evaluated. The presence of a chlorine atom on the pyrrole ring was crucial to reduce cardiotoxicity. The presence of a 2-(ethyl-amino)ethylcarbamoyl group as a substituent at the C-4′ position of the pyrrole enhanced the antitumor activities notably. IC₅₀ values as low as 0.32, 0.67, 1.19 and 1.22 μM were achieved against non-small cell lung cancer (A549), oral epithelial (KB), melanoma (K111) and large cell lung cancer cell lines (NCI-H460), respectively.

Magnetic targeting strategies in gene delivery

Gene delivery is a process of the insertion of transgenes into cells with the purpose to obtain the expression of encoded protein. The therapeutic application of this process is termed gene therapy, which is becoming a promising instrument to treat genetic and acquired diseases. Although numerous methods of gene transfer have already been developed, including biological, physical and chemical approaches, the optimal strategy has to be discovered. Importantly, it should be effective, selective and safe to be translated to the clinic. Magnetic targeting has been demonstrated as an effective strategy to decrease side effects of gene transfer, while increasing the selectivity and efficiency of the applied vector. This article will focus on the latest progress in the development of different magnetic vectors, based on both viral and nonviral gene delivery agents. It will also include a description of magnetic targeting applications in stem cells and in vivo, which has gained interest in recent years due to the rapid development of technology.

Heme oxygenase-1: a molecular brake on hepatocellular carcinoma cell migration

Hepatocellular carcinoma (HCC) is a fatal disease with great public health impact worldwide. Heme oxygenase (HO)-1 has recently been reported as an important player in tumor angiogenesis and metastasis. However, the role of HO-1 in liver cancer metastasis is unclear. In this study, we explored genetic differences and downstream signal transduction pathways of HO-1 in liver cancer cell lines. HO-1 wild-type and mutant cell lines were generated from human liver cancer cell line HepG2. The overexpression of wild-type HO-1 decreased the migration of HepG2 cells. In contrast, the overexpression of mutant HO-1G143H increased the migration of the cancer cells. Interleukin (IL)-6 is one of the major downstream molecules that mediated this process because IL-6 expression and migration are suppressed by HO-1 and increased when HO-1 is knocked down by shRNA. In addition, we demonstrated carbon monoxide (CO) and p38MAPK are the cofactors in this signal pathway. In vivo animal model demonstrated HO-1 inhibited the tumor growth. In conclusion, in vitro and in vivo data show HO-1 inhibits the human HCC cells migration and tumor growth by suppressing the expression of IL-6. The heme degradation product CO is a cofactor in this process and inhibits p38MAPK phosphorylation.

Comparison of cardiac magnetic resonance imaging features of isolated left ventricular non-compaction in adults versus dilated cardiomyopathy in adults

AIM

To compare cardiac magnetic resonance imaging (MRI) features between isolated left ventricular non-compaction (IVNC) and dilated cardiomyopathy (DCM) in adults.

MATERIALS AND METHODS

A consecutive series of 50 patients with IVNC from a single institution were reviewed. During the same period, 50 patients with DCM who had prominent trabeculations, who were matched for age, gender, and body surface area, were prospectively included. Left ventricular (LV) morphology and function were assessed using cardiac MRI.

RESULTS

Compared with patients with DCM, patients with IVNC had a significantly lower LV sphericity index and end-diastolic volume index (LVEDVI) and a greater LV ejection fraction (LVEF), number of trabeculated segments, and ratio of non-compacted to compacted myocardium (NC/C ratio). There were no significant differences in stroke volume index, cardiac output, and cardiac index between the two patient groups. In patients with IVNC, the number of trabeculated segments and the NC/C ratio correlated positively with LVEDVI (r=0.626 and r=0.559, respectively) and negatively with LVEF (r=-0.647 and r=-0.521, respectively, p<0.001 for all). In patients with DCM, the number of non-compacted segments and the NC/C ratio had no correlation with either the LVEDVI (r=-0.082 and r=-0.135, respectively) or the LVEF (r=0.097 and r=0.205, respectively).

CONCLUSION

There are demonstrable morphological and functional differences between IVNC and DCM at LV assessment using cardiac MRI. The occurrence of trabeculated myocardium might be due to a different pathophysiological mechanism.

[DNA damage caused by suicide gene therapy system under Tet-On regulation in breast cancer cells]

OBJECTIVE

To determine the effect and molecular mechanism of DNA damage caused by suicide gene therapy system HSV-TK/GCV under Tet-On regulation in human breast cancer cell line MCF-7 infected by recombinant adeno-associated virus (rAAV).

METHODS

We used comet assay to detect the effect of HSV-TK/GCV suicide gene regulation system on MCF-7 DNA damage, and analyzed the expression change of relative DNA damage response active genes and proteins with RT-PCR and Western blot.

RESULTS

Compared with other control groups, the comet assay showed that MCF-7 cells with HSV-TK/GCV treatment had obvious comet tails, and the expression level of DNA damage response active genes and proteins changed obviously in the HSV-TK/GCV treatment group,such as ATM, p53 and p27,but CyclinE and CDK2 did not change.

CONCLUSION

DNA damage on MCF-7 cells is resulted from HSV-TK/GCV in suicide gene therapy system through a p53-dependent signal pathway, causing cell cycle arrest and cell death.

Patterning human stem cells and endothelial cells with laser printing for cardiac regeneration

Recent study showed that mesenchymal stem cells (MSC) could inhibit apoptosis of endothelial cells in hypoxic condition, increase their survival, and stimulate the angiogenesis process. In this project we applied Laser-Induced-Forward-Transfer (LIFT) cell printing technique and prepared a cardiac patch seeded with human umbilical vein endothelial cells (HUVEC) and human MSC (hMSC) in a defined pattern for cardiac regeneration. We seeded HUVEC and hMSC in a defined pattern on a Polyester urethane urea (PEUU) cardiac patch. On control patches an equal amount of cells was randomly seeded without LIFT. Patches were cultivated in vitro or transplanted in vivo to the infarcted zone of rat hearts after LAD-ligation. Cardiac performance was measured by left ventricular catheterization 8 weeks post infarction. Thereafter hearts were perfused with fluorescein tomato lectin for the assessment of functional blood vessels and stored for histology analyses. We demonstrated that LIFT-derived cell seeding pattern definitely modified growth characteristics of co-cultured HUVEC and hMSC leading to increased vessel formation and found significant functional improvement of infarcted hearts following transplantation of a LIFT-tissue engineered cardiac patch. Further, we could show enhanced capillary density and integration of human cells into the functionally connected vessels of murine vascular system. LIFT-based Tissue Engineering of cardiac patches for the treatment of myocardial infarction might improve wound healing and functional preservation.

Hypoxic/normoxic preconditioning increases endothelial differentiation potential of human bone marrow CD133+ cells

CD133+ cells are hemangioblasts that have capacity to generate into both hematopoietic and endothelial cells (ECs). Hypoxia/normoxia has shown to be the regulator of the balance between stemness and differentiation. In this study we performed Agilent's whole human genome oligo microarray analysis and examined the differentiation potential of the bone-marrow-derived CD133+ cells after hypoxic/normoxic preconditioning of CD133+ cells. Results showed that there was no significant increase in erythroid colony forming unit (CFU-E) and CFU-granulocyte, erythrocyte, monocyte, and megakaryocyte formation with cells treated under hypoxia/normoxia. However, a significant increment of EC forming unit at 24 h (143.2 +/- 8.0%) compared to 0 h (100 +/- 11.4%) was observed in CFU-EC analysis. Reverse transcription-polymerase chain reaction and immunostaining analysis showed that the differentiated cells diminished hematopoietic stem cell surface markers and acquired the gene markers and functional phenotype of ECs. The transcriptome profile revealed a cluster of 232 downregulated and 498 upregulated genes in cells treated for 24 h under hypoxia. The upregulated genes include angiogenic genes, angiogenic growth factor genes, angiogenic cytokine and chemokine genes, as well as angiogenic-positive regulatory genes, including FGFBP1, PDGFB, CCL15, CXCL12, CXCL6, IL-6, PTN, EREG, ERBB2, EDG5, FGF3, FHF2, GDF15, JUN, L1CAM, NRG1, NGFR, and PDGFB. On the other hand, angiogenesis inhibitors and related genes, including IL12A, MLLT7, STAB1, and TIMP2, are downregulated. Taken together, hypoxic/normoxic preconditioning may lead to the differentiation of CD133+ cells toward endothelial lineage, which may improve the current clinical trial studies.

Laser printing of skin cells and human stem cells

Laser printing based on laser-induced forward transfer (LIFT) is a new biofabrication technique for the arrangement of biological materials or living cells in well-defined patterns. In the current study, skin cell lines (fibroblasts/keratinocytes) and human mesenchymal stem cells (hMSC) were chosen for laser printing experiments due to their high potential in regeneration of human skin and new application possibilities of stem cell therapy. To evaluate the influence of LIFT on the cells, their survival rate, their proliferation and apoptotic activity, and the DNA damages and modifications of their cell surface markers were assessed and statistically evaluated over several days. The cells survived the transfer procedure with a rate of 98%  +/- 1% standard error of the mean (skin cells) and 90%  +/- 10% (hMSC), respectively. All used cell types maintain their ability to proliferate after LIFT. Further, skin cells and hMSC did not show an increase of apoptosis or DNA fragmentation. In addition, the hMSC keep their phenotype as proven by fluorescence activated cell sorting (FACS) analysis. This study demonstrates LIFT as a suitable technique for unharmed computer-controlled positioning of different cell types and a promising tool for future applications in the ex vivo generation of tissue replacements.

Cell origin of human mesenchymal stem cells determines a different healing performance in cardiac regeneration

The possible different therapeutic efficacy of human mesenchymal stem cells (hMSC) derived from umbilical cord blood (CB), adipose tissue (AT) or bone marrow (BM) for the treatment of myocardial infarction (MI) remains unexplored. This study was to assess the regenerative potential of hMSC from different origins and to evaluate the role of CD105 in cardiac regeneration. Male SCID mice underwent LAD-ligation and received the respective cell type (400.000/per animal) intramyocardially. Six weeks post infarction, cardiac catheterization showed significant preservation of left ventricular functions in BM and CD105(+)-CB treated groups compared to CB and nontreated MI group (MI-C). Cell survival analyzed by quantitative real time PCR for human GAPDH and capillary density measured by immunostaining showed consistent results. Furthermore, cardiac remodeling can be significantly attenuated by BM-hMSC compared to MI-C. Under hypoxic conditions in vitro, remarkably increased extracellular acidification and apoptosis has been detected from CB-hMSC compared to BM and CD105 purified CB-derived hMSC. Our findings suggests that hMSC originating from different sources showed a different healing performance in cardiac regeneration and CD105(+) hMSC exhibited a favorable survival pattern in infarcted hearts, which translates into a more robust preservation of cardiac function.

The nuclear scaffold protein SAF-A is required for kinetochore-microtubule attachment and contributes to the targeting of Aurora-A to mitotic spindles

Segregation of chromosomes during cell division requires correct formation of mitotic spindles. Here, we show that a scaffold attachment factor A (SAF-A), also known as heterogeneous nuclear ribonucleoprotein-U, contributes to the attachment of spindle microtubules (MTs) to kinetochores and spindle organization. During mitosis, SAF-A was localized at the spindles, spindle midzone and cytoplasmic bridge. Depletion of SAF-A by RNA interference induced mitotic delay and defects in chromosome alignment and spindle assembly. We found that SAF-A specifically co-immunoprecipitated with the chromosome peripheral protein nucleolin and the spindle regulators Aurora-A and TPX2, indicating that SAF-A is associated with nucleolin and the Aurora-A-TPX2 complex. SAF-A was colocalized with TPX2 and Aurora-A in spindle poles and MTs. Elimination of TPX2 or Aurora-A from cells abolished the association of SAF-A with the mitotic spindle. Interestingly, SAF-A can bind to MTs and contributes to the targeting of Aurora-A to mitotic spindle MTs. Our finding indicates that SAF-A is a novel spindle regulator that plays an essential role in kinetochore-MT attachment and mitotic spindle organization.

Optical transfection using an endoscope-like system

Optical transfection is a powerful method for targeted delivery of therapeutic agents to biological cells. A tightly focused pulsed laser beam may transiently change the permeability of a cell membrane to facilitate the delivery of foreign genetic material into cells. We report the first realization of an endoscope-like integrated system for optical transfection. An imaging fiber (coherent optical fiber bundle) with ∼ 6000 cores (pixels) embedded in a fiber cladding of ∼ 300 μm in diameter, produces an image circle (area) of ∼ 270 μm diam. This imaging fiber, with an ordered axicon lens array chemically etched at its exit face, is used for the delivery of a femtosecond laser to the cell membrane for optical transfection along with subcellular resolution imaging. A microcapillary-based microfluidic system for localized drug delivery was also combined in this miniature, flexible system. Using this novel system, a plasmid transfection efficiency up to ∼ 72% was obtained for CHO-K1 cells. This endoscope-like system opens a range of exciting applications, in particular, in the targeted in vivo optical microsurgery area.

Cloning, partial sequence, and single-nucleotide polymorphism of the ryanodine receptor gene of the Pacific white shrimp Litopenaeus vannamei (Penaeidae)

Ryanodine receptor/calcium release channel is a large protein that plays an essential role in muscle contraction; mutations in the ryanodine receptor gene affect sensitivity to stress. As a first step towards investigating the relationship between the ryanodine receptor and shrimp cramped muscle syndrome, we cloned, partially sequenced, and examined single-nucleotide polymorphisms (SNPs) of the ryanodine receptor gene of the Pacific white shrimp (Litopenaeus vannamei). The nucleotide sequence of a 15.06-kb L. vannamei genomic DNA segment containing a partial ryanodine receptor gene sequence was determined (deposited in GenBank nucleotide database: HM367069). Direct sequencing of PCR-amplified ryanodine receptor exons with their intron-flanking regions in 10 cramped muscle syndrome shrimp and 10 healthy shrimp, revealed seven SNPs. Five of them (1713A/G, 1749T/C, 1755T/C, 3965G/A, and 8737C/T) are located in exons; however, they appear to be neutral (synonymous), since they do not alter the encoded amino acid. The other SNPs (1553C/T and 13337A/G) are in introns. The SNPs identified in the ryanodine receptor gene could be useful for association studies aimed at determining the physiological role of the ryanodine receptor in cramped muscle syndrome of shrimp.

Animal models of cardiac disease and stem cell therapy

Animal models that mimic cardiovascular diseases are indispensable tools for understanding the mechanisms underlying the diseases at the cellular and molecular level. This review focuses on various methods in preclinical research to create small animal models of cardiac diseases, such as myocardial infarction, dilated cardiomyopathy, heart failure, myocarditis and cardiac hypertrophy, and the related stem cell treatment for these diseases.

Autologous valve replacement-CD133+ stem cell-plus-fibrin composite-based sprayed cell seeding for intraoperative heart valve tissue engineering

OBJECTIVE

The development of biological valve prostheses with lifetime native-like performance and optimal host engraftment is an ultimate goal of heart valve tissue engineering. We describe a new concept for autologous graft coating based on a CD133(+)-stem-cells-plus-fibrin (SC+F) complex processed from bone marrow and peripheral blood of a single patient.

METHODS

CD133(+)-SC (1 × 10(6) cells/mL) from human bone marrow and autologous fibrin (20 mg/mL) were administered simultaneously via spray administration using the novel Vivostat Co-Delivery System. During static cultivation, SC+F performance was monitored for 20 days after delivery and compared with controls. For dynamic testing SC+F-composite was sprayed on a decellularized porcine pulmonary valve and transferred to a bioreactor under pulsatile flow conditions for 7 days.

RESULTS

Static cultivation of SC+F-composite induced significant improvements in stem cell proliferation as compared with controls. For dynamic testing, microscopic analyses on a smooth engineered heart valve surface detected homogenous distribution of stem cells. Ultrasonic analysis revealed native-like valve performance. Applied CD133(+) stem cells differentiated into endothelial-like cells positive for CD31 and vascular endothelial growth factor receptor 2 and engrafted the valve. However, occasional delamination was observed.

CONCLUSION

SC+F serves as an excellent autologous matrix for intraoperative tissue engineering of valve prostheses promising optimal in vivo integration. However, stability remains an issue.

Alternans in genetically modified langendorff-perfused murine hearts modeling catecholaminergic polymorphic ventricular tachycardia

The relationship between alternans and arrhythmogenicity was studied in genetically modified murine hearts modeling catecholaminergic polymorphic ventricular tachycardia (CPVT) during Langendorff perfusion, before and after treatment with catecholamines and a β-adrenergic antagonist. Heterozygous (RyR2^p/s) and homozygous (RyR2^s/s) RyR2-P2328S hearts, and wild-type (WT) controls, were studied before and after treatment with epinephrine (100 nM and 1 μM) and propranolol (100 nM). Monophasic action potential recordings demonstrated significantly greater incidences of arrhythmia in RyR2^p/s and RyR2^s/s hearts as compared to WTs. Arrhythmogenicity in RyR2^s/s hearts was associated with alternans, particularly at short baseline cycle lengths. Both phenomena were significantly accentuated by treatment with epinephrine and significantly diminished by treatment with propranolol, in full agreement with clinical expectations. These changes took place, however, despite an absence of changes in mean action potential durations, ventricular effective refractory periods or restitution curve characteristics. Furthermore pooled data from all hearts in which arrhythmia occurred demonstrated significantly greater alternans magnitudes, but similar restitution curve slopes, to hearts that did not demonstrate arrhythmia. These findings thus further validate the RyR2-P2328S murine heart as a model for human CPVT, confirming an alternans phenotype in common with murine genetic models of the Brugada syndrome and the congenital long-QT syndrome type 3. In contrast to these latter similarities, however, this report demonstrates the dissociation of alternans from changes in the properties of restitution curves for the first time in a murine model of a human arrhythmic syndrome.

Construction of ureteral grafts by seeding urothelial cells and bone marrow mesenchymal stem cells into polycaprolactone-lecithin electrospun fibers

The aim of the present study was to investigated the construction of polycaprolactone-lecithin (PCL-L) electrospun fibers as a novel scaffold material for a tissue-engineered ureter. The effect of bone marrow mesenchymal stem cells (BM-MSCs) on the neovascularization of the scaffolds and the viability of planted urothelial cells (UCs) on PCL-L were also studied. UCs were obtained from New Zealand rabbit bladders, cultured and then seeded onto the lumen of the tubular scaffolds before being subcutaneously transplanted into the space of nude mice. The cultured UCs showed vacuolar degeneration after 7 days of transplantation and they gradually degraded thereafter. To facilitate the regeneration of the tissue-engineered ureter and the survival of UCs in the implant, MSCs were seeded into the tubular grafts by rolling up the nanofibrous membrane, followed by the seeding of UCs. This facilitated the survival of the UCs, which formed several cellular layers after 30 days. The mean microvessel density was significantly increased in tissues seeded with MSCs. Cell-tracking experiments revealed that the transplanted MSCs did not integrate directly into capillaries for angiogenesis. Our results demonstrated that the PCL-L electrospun fibrous scaffold has a high potential for a tissue-engineered ureter especially when seeded with BM-MSCs, which enhanced angiogenesis.

Influence of N(2)O(4) on multifocal electroretinogram in winstar mice

AIM

To record multifocal electroretinogram from different dosage of N(2)O(4) injected mice. In order to provide a foundation for further study.

METHODS

Normal winstar mice which were injected by different dosage of N(2)O(4) were studied for recording multifocal electroretinogram in the same time in the evening after N(2)O(4) injection.

RESULTS

The latency and amplitude density of "b" wave of each ring of multifocal electroretinogram was studied. The latency of "b" wave of each ring of multifocal electroretinogram of each group varies to each other. But the difference of the amplitude of "b" wave of multifocal electroretinogram of each ring between each group had no significance.

CONCLUSION

Recording multifocal electroretinogram of N(2)O(4) injected mice will give more support for further study in related science and clinic research.

Transgenic mice overproducing human thioredoxin-1, an antioxidative and anti-apoptotic protein, prevents diabetic embryopathy

AIMS/HYPOTHESIS

Experimental studies have suggested that apoptosis is involved in diabetic embryopathy through oxidative stress. However, the precise mechanism of diabetic embryopathy is not yet clear. Thioredoxin (TRX) is a small, ubiquitous, multifunctional protein, which has recently been shown to protect cells from oxidative stress and apoptosis. Using transgenic mice that overproduce human TRX-1 (TRX-Tg mice), we examined whether oxidative stress is involved in fetal dysmorphogenesis in diabetic pregnancies.

METHODS

Non-diabetic and streptozotocin-induced diabetic (DM) female mice were mated with male TRX-Tg mice. Pregnant mice were killed either at day 10 or day 17 of gestation, and viable fetuses and their placentas were recovered, weighed and assessed for gross and histological morphology, biochemical markers and gene expression.

RESULTS

In both wild-type (WT) and transgenic (Tg) groups, fetal and placental weights in the diabetic group were significantly decreased compared with the non-diabetic group. The incidence of malformation was higher in the diabetic group, and was significantly decreased in the TRX-Tg group (DM-WT vs DM-Tg; 28.6% vs 10.4%). Oxidative stress markers such as thiobarbituric acid reactive substances and 8-hydroxy-2'-deoxyguanosine were increased in DM-WT group fetuses but were decreased in fetuses from the DM-Tg group. Furthermore, immunohistochemically assayed apoptosis and cleaved caspase-3 production in embryonic neuroepithelial cells was significantly increased in the DM-WT group, and was significantly decreased in the DM-Tg group.

CONCLUSIONS/INTERPRETATION

These results indicate that oxidative stress is involved in diabetic embryopathy, and that the antioxidative protein TRX at least partially prevents diabetic embryopathy via suppression of apoptosis.

Integrated optical transfection system using a microlens fiber combined with microfluidic gene delivery

Optical transfection is a promising technique for the delivery of foreign genetic material into cells by transiently changing the permeability of the cell membrane. Of the different optical light sources that have been used, femtosecond laser based transfection has been one of the most effective methods for optical transfection which is generally implemented using a free space bulk optical setup. In conventional optical transfection methods the foreign genetic material to be transfected is homogenously mixed in the medium. Here we report the first realization of an integrated optical transfection system which can achieve transfection along with localized drug delivery by combining a microlens fiber based optical transfection system with a micro-capillary based microfluidic system. A fiber based illumination system is also incorporated in the system in order to achieve visual identification of the cell boundaries during transfection. A novel fabrication method is devised to obtain easy and inexpensive fabrication of microlensed fibers, which can be used for femtosecond optical transfection. This fabrication method offers the flexibility to fabricate a microlens which can focus ultra-short laser pulses at a near infrared wavelength to a small focal spot (~3 µm) whilst keeping a relatively large working distance (~20 µm). The transfection efficiency of the integrated system with localized plasmid DNA delivery, is approximately 50%, and is therefore comparable to that of a standard free space transfection system. Also the use of integrated system for localized gene delivery resulted in a reduction of the required amount of DNA for transfection. The miniaturized, integrated design opens a range of exciting experimental possibilities, including the dosing of tissue slices, targeted drug delivery, and targeted gene therapy in vivo.

Near-infrared light emitting luciferase via biomineralization

A new strategy based on biomineralization is presented to rationally tune the emission wavelength of luciferase. In this study luciferase (Luc8) was used as a template to direct the synthesis of near-infrared (NIR) light emitting PbS quantum dots (QDs) at ambient conditions to form a Luc8-PbS nanocomplex. The as-synthesized PbS QDs exhibited photoluminescence in the range of 800-1050 nm, and the Luc8 enzyme remained active within the Luc8-PbS complex. Upon the addition of the substrate coelenterazine, the energy produced by Luc8 was nonradiatively transferred to PbS QDs via bioluminescence resonance energy transfer (BRET) and enabled the complex to emit NIR light. This is the first study to form dual functional bioinorganic hybrid nanostructures via active enzyme-templated synthesis of inorganic nanomaterials.

Arterial remodeling of advanced basilar atherosclerosis: a 3-tesla MRI study

BACKGROUND

There are limited studies on wall imaging of human basilar artery (BA). Our aim was to investigate remodeling mode of advanced BA atherosclerosis using 3-T MRI.

METHODS

Thirty-two consecutive symptomatic patients with atherosclerotic BA stenosis >or=70% were imaged with a 3-T magnetic resonance scanner. Proton density-weighted (PDW) cross-sectional images with submillimeter voxel size were obtained. The vessel area (VA) and lumen area (LA) at the maximal lumen narrowing (MLN) site and reference site were measured. Intraobserver and interobserver variability was determined by intraclass correlation coefficient (ICC). Wall area (WA) was estimated by VA - LA. Plaque size (PS) was estimated by WA at MLN site--reference WA. Percent plaque burden was calculated as (PS/VA at MLN site) x 100%. Remodeling index (RI) was the ratio of VA at MLN site to reference VA. RI >or=1.05 was defined as positive remodeling (PR) and RI <1.05 as non-PR.

RESULTS

Measurements of cross-sectional BA images were available in 30 of 32 patients. Intraobserver or interobserver variability was small, with ICC ranging from 0.955 to 0.996. The mean RI of the 30 patients was 1.2 +/- 0.4. PR was found in 19 (63.3%) patients and non-PR in 11 (36.7%) patients. Compared with the non-PR group, the PR group had greater PS (15.0 +/- 9.3 mm(2) vs 6.4 +/- 3.9 mm(2), p = 0.007) and greater percent plaque burden (50.5 +/- 9.9% vs 28.5 +/- 12.7%, p < 0.0001).

CONCLUSIONS

3-T high-resolution PDW imaging is a reproducible tool for measuring BA dimensions. In patients with advanced BA atherosclerosis, PR lesions are more frequently observed and contain larger plaques than non-PR lesions.

Facile synthesis, silanization, and biodistribution of biocompatible quantum dots

A facile strategy for the synthesis of silica-coated quantum dots (QDs) for in vivo imaging is reported. All the QD synthesis and silanization steps are conducted in water and methanol under mild conditions without involving any organometallic precursors or high-temperature, oxygen-free environments. The as-prepared silica-coated QDs possess high quantum yields and are extremely stable in mouse serum. In addition, the silanization method developed here produces nanoparticles with small sizes that are difficult to achieve via conventional silanization methods. The silica coating helps to prevent the exposure of the QD surface to the biological milieu and therefore increases the biocompatibility of QDs for in vivo applications. Interestingly, the silica-coated QDs exhibit a different biodistribution pattern from that of commercially available Invitrogen QD605 (carboxylate) with a similar size and emission wavelength. The Invitrogen QD605 exhibits predominant liver (57.2% injected dose (ID) g(-1)) and spleen (46.1% ID g(-1)) uptakes 30 min after intravenous injection, whereas the silica-coated QDs exhibit much lower liver (16.2% ID g(-1)) and spleen (3.67% ID g(-1)) uptakes but higher kidney uptake (8.82% ID g(-1)), blood retention (15.0% ID g(-1)), and partial renal clearance. Overall, this straightforward synthetic strategy paves the way for routine and customized synthesis of silica-coated QDs for biological use.

Polyethylenimine-mediated gene delivery into human bone marrow mesenchymal stem cells from patients

Transplantation of mesenchymal stem cells (MSCs) derived from adult bone marrow has been proposed as a potential therapeutic approach for post-infarction left ventricular (LV) dysfunction. However, age-related functional decline of stem cells has restricted their clinical benefits after transplantation into the infarcted myocardium. The limitations imposed on patient cells could be addressed by genetic modification of stem cells. This study was designed to improve our understanding of genetic modification of human bone marrow derived mesenchymal stem cells (hMSCs) by polyethylenimine (PEI, branched with Mw 25 kD), one of non-viral vectors that show promise in stem cell genetic modification, in the context of cardiac regeneration for patients. We optimized the PEI-mediated reporter gene transfection into hMSCs, evaluated whether transfection efficiency is associated with gender or age of the cell donors, analysed the influence of cell cycle on transfection and investigated the transfer of therapeutic vascular endothelial growth factor gene (VEGF). hMSCs were isolated from patients with cardiovascular disease aged from 41 to 85 years. Optimization of gene delivery to hMSCs was carried out based on the particle size of the PEI/DNA complexes, N/P ratio of complexes, DNA dosage and cell viability. The highest efficiency with the cell viability near 60% was achieved at N/P ratio 2 and 6.0 μg DNA/cm². The average transfection efficiency for all tested samples, middle-age group (<65 years), old-age group (>65 years), female group and male group was 4.32%, 3.85%, 4.52%, 4.14% and 4.38%, respectively. The transfection efficiency did not show any correlation either with the age or the gender of the donors. Statistically, there were two subpopulations in the donors; and transfection efficiency in each subpopulation was linearly related to the cell percentage in S phase. No significant phenotypic differences were observed between these two subpopulations. Furthermore, PEI-mediated therapeutic gene VEGF transfer could significantly enhance the expression level.

How to track cellular aging of mesenchymal stromal cells?

Mesenchymal stromal cells (MSC) are currently tested in a large number of clinical trials and raise high hope in regenerative medicine. These cells have to be expanded in vitro before transplantation and several studies demonstrated that long-term culture evokes continuous changes in MSC: proliferation rate decays, the cell size increases, differentiation potential is affected, chromosomal instabilities may arise and molecular changes are acquired. Long-term culture of cell preparations might also have therapeutic consequences, although this has hardly been addressed in ongoing trials so far. Reliable therapeutic regimens necessitate quality control of cellular products. This research perspective summarizes available methods to track cellular aging of MSC. We have demonstrated that gene expression changes and epigenetic modifications are continuously acquired during replicative senescence. Molecular analysis of a suitable panel of genes might provide a robust tool to assess efficiency and safety of long-term expansion.

Intracardiac injection of matrigel induces stem cell recruitment and improves cardiac functions in a rat myocardial infarction model

Matrigel promotes angiogenesis in the myocardium from ischemic injury and prevents remodelling of the left ventricle. We assessed the therapeutic efficacy of intracardiac matrigel injection and matrigel-mediated stem cell homing in a rat myocardial infarction (MI) model. Following MI, matrigel (250 μl) or phosphate-buffered solution (PBS) was delivered by intracardiac injection. Compared to the MI control group (MI-PBS), matrigel significantly improved left ventricular function (n= 11, P < 0.05) assessed by pressure–volume loops after 4 weeks. There is no significant difference in infarct size between MI-matrigel (MI-M; 21.48 ± 1.49%, n= 10) and MI-PBS hearts (20.98 ± 1.25%, n= 10). The infarct wall thickness of left ventricle is significantly higher (P < 0.01) in MI-M (0.72 ± 0.02 mm, n= 10) compared with MI-PBS (0.62 ± 0.02 mm, n= 10). MI-M hearts exhibited higher capillary density (border 130.8 ± 4.7 versus 115.4 ± 6.0, P < 0.05; vessels per high-power field [HPF; 400×], n= 6) than MI-PBS hearts. c-Kit⁺ stem cells (38.3 ± 5.3 versus 25.7 ± 1.5 c-Kit⁺ cells per HPF [630×], n= 5, P < 0.05) and CD34⁺ cells (13.0 ± 1.51 versus 5.6 ± 0.68 CD34⁺ cells per HPF [630×], n= 5, P < 0.01) were significantly more numerous in MI-M than in MI-PBS in the infarcted hearts (n= 5, P < 0.05). Intracardiac matrigel injection restores myocardial functions following MI, which may attribute to the improved recruitment of CD34⁺ and c-Kit⁺ stem cells.

Intervention study of the association of antibiotic utilization measures with control of extended-spectrum beta-lactamase (ESBL)-producing bacteria

We investigated the effects of replacing third-/fourth-generation cephalosporins with piperacillin-tazobactam on the rate of acquisition of extended spectrum beta-lactamase-producing Klebsiella pneumoniae and Escherichia coli by patients hospitalized in a Department of Respiratory Medicine. This 9-month, prospective, non-controlled, intervention study comprised two phases: a 3-month pre-intervention phase (Phase I) and a 6-month intervention phase (Phase II), during which the use of third-/forth-generation cephalosporins was restricted and replaced by piperacillin-tazobactam. Rectal swabs were obtained within 24 h after admission (baseline screening), weekly, and 48 h before discharge during Phase I and the last 3 months of Phase II (Phase IIb). Swabs were tested for E. coli and K. pneumoniae, and extended spectrum beta-lactamase production was detected with the double disc test. Use of third/fourth-generation cephalosporins decreased by 63.0% and 100%, respectively; while the use of piperacillin-tazobactam increased by 28-fold. The rate of acquisition of extended spectrum beta-lactamase-producing E. coli and K. pneumoniae together in rectal swab specimens decreased in Phase IIb as compared with Phase I (19.5% vs 29.5%). Few rectal swab specimens were positive for extended spectrum beta-lactamases-producing K. pneumoniae, and no substantial decrease in the rate of its acquisition was observed.

Intraobserver and interobserver variability for measuring the wall area of the basilar artery at the level of the trigeminal ganglion on high-resolution MR images

We evaluated the intraobserver and interobserver variability for WA measurement of an atherosclerotic BA by using HRMRI. Ten consecutive patients underwent HRMRI, and the WA of the BA at the level of the trigeminal ganglion was measured by 2 independent readers and repeated by 1 reader 1 month later. There was strong agreement for intraobserver and interobserver measurements in the ICC and by the Bland-Altman method. Measurement of the WA in an atherosclerotic BA by HRMRI was reproducible.

[Efficacy and safety in treatment of ocular neovascularization by Bevacizumab versus Ranibizumab: a meta-analysis]

OBJECTIVE

To evaluate the efficacy and safety in treatment of ocular neovascularization by Bevacizumab versus Ranibizumab.

METHODS

It was a systematic review and meta-analysis. According to evaluation guidelines of Cochrane collaboration, clinical controlled trials (CCTs) comparing Bevacizumab and Ranibizumab in treatment of ocular neovascularization were searched using Medline, EMbase, the Cochrane Library and CBM. Methodology qualities of literatures were performed by experienced researchers according to the Jadad Score. RevMan 4.2 offered by Cochrane was used to do the meta-analysis. The differences of efficacy and safety in treatment of ocular neovascularization by Bevacizumab versus Ranibizumab were analyzed through statistical test for incorporative effect (the test results were shown by Z value).

RESULTS

Only 7 literatures came into meta-analysis (1620 eyes). The result of analysis showed that Bevacizumab could improve the BCVA and cut down the CFT in treatment of ocular neovascularization, and that Bevacizumab did not display any statistically difference in improving best-corrected visual acuity (converted to logMAR, Bevacizumab group, from -0.9031 + or - 0.0323 to -0.7635 + or - 0.0214, improving by 0.1396 + or - 0.0225; Ranibizumab group, from -0.9345 + or - 0.0194 to -0.8050 + or - 0.0221, improving by 0.1295 + or - 0.0203, Z = 0.56, P = 0.57), and cutting down the central foveal thickness [Bevacizumab group, from (325.4 + or - 52.3) microm to (269.1 + or - 21.3) microm, cutting down by (56.3 + or - 18.5) microm; Ranibizumab group, from (342.0 + or - 45.1) microm to (277.2 + or - 35.5) microm, cutting down by (67.8 + or - 23.2) microm, Z = 1.13, P = 0.26] and safety [inflammation at injection site, Bevacizumab group, 4.1% (34/823 eyes); Ranibizumab group, 3.8% (30/797 eyes), Z = 0.74, P = 0.46; subconjunctival hemorrhage, Bevacizumab group, 3.3% (27/823 eyes); Ranibizumab group, 3.4% (27/797 eyes), Z = 0.98, P = 0.33; total complications, Bevacizumab group, 10.2% (84/823 eyes); Ranibizumab group, 9.5% (76/797 eyes), chi(2) = 0.21, P = 0.65] compared with Ranibizumab.

CONCLUSIONS

Meta-analysis shows that Bevacizumab has equal efficacy and safety to Ranibizumab in treatment of ocular neovascularization. However, a high quality perspective study is still required for further analysis.

Nucleic acid-passivated semiconductor nanocrystals: biomolecular templating of form and function

Bright, photostable luminescent labels are powerful tools for the in vitro and in vivo imaging of biological events. Semiconductor nanocrystals have emerged as attractive alternatives to commonly used organic lumophores because of their high quantum yields and the spectral tunability that can be achieved through synthetic control. Although conventional synthetic methods generally yield high-quality nanocrystals with excellent optical properties for biological imaging, ligand exchange and biological conjugation are necessary to make nanocrystals biocompatible and biospecific. These steps can substantially deteriorate the optical characteristics of these nanocrystals. Moreover, the complexity of multistep nanocrystal synthesis, typically requiring inert and anhydrous conditions, prohibits many end users of these lumiphores from generating their own custom materials. We sought to streamline semiconductor nanocrystal synthesis and develop synthetic routes that would be accessible to scientists from all disciplines. In search of such an approach, we turned to nucleic acids as a programmable and versatile ligand set and found that these biomolecules are indeed appropriate for biocompatible semiconductor nanocrystals preparation. In this Account, we summarize our work on nucleic acids-programmed nanocrystal synthesis that has resulted in the successful development of a one-step synthesis of biofunctionalized nanocrystals in aqueous solution. We first discuss results obtained with nucleotide-capped cadmium and lead chalcogenide-based nanocrystals that served to guide further investigation of polynucleotide-assisted synthesis. We investigated the roles of individual nucleobases and their structures in passivation of the surfaces of nanocrystals and modulating morphology and optical characteristics. The nucleic acid structures and sequences and the reaction conditions greatly influence the nanocrystals' optical properties and morphologies. Moreover, studies using live cells reveal low toxicity and rapid uptake of DNA-passivated CdS nanocrystals, demonstrating their suitability for bioimaging. Finally, we describe a new approach that leads to the production of biofunctionalized, DNA-capped nanocrystals in a single step. Chimeric DNA molecules enable this strategy, providing both a domain for nanocrystal passivation and a domain for biomolecule recognition. Nanocrystals synthesized using this approach possess good spectral characteristics as well as high specificity to cognate DNA, protein, and cancer cell targets. Overall, this approach could make nanocrystal lumiphores more readily accessible to researchers working in the biological sciences.