Knockdown of Tripartite Motif Containing 28 suppresses the migration, invasion and epithelial-mesenchymal transition in ovarian carcinoma cells through down-regulation of Wnt/β-catenin signaling pathway

Tripartite motif containing 28 (TRIM28) is a transcriptional corepressor of Kruppel-associated box zinc finger protein, which has been reported to participate in carcinogenesis. Nonetheless, whether TRIM28 plays a role in the metastasis of ovarian carcinoma (OC) is unclear and requires further investigation. In this study, two OC cell lines (A2780 and OVCAR-3) with stable low expression of TRIM28 were established via RNA interference. We found that the migratory and invasive ability of TRIM28-silenced OC cells significantly decreased. The expression and activity of matrix metallopeptidase (MMP)-2 and MMP-9 in these OC cells were inhibited. The TRIM28 shRNA also suppressed the epithelial-mesenchymal transition (EMT) of OC cells as evidenced by the up-regulated E-cadherin and the downregulated Vimentin and N-cadherin. Additionally, the Wnt/β-catenin signaling pathway was suppressed in TRIM28-silenced OC cells: the activity of β-catenin was inhibited, the expression of total and nuclear β-catenin, Axin 2, T-cell factor 1 (TCF1) and lymphoid enhancer binding factor 1 (LEF1) were decreased, whereas the phosphorylation of β-catenin at Ser33/37 was enhanced. Further, re-expression of active β-catenin in TRIM28-silenced OC cells partly restored their metastasis in vitro. Taken together, our study demonstrates a contributory role of TRIM28 in OC metastasis in vitro, suggesting TRIM28 as a novel therapeutic target for this malignant tumor.

[Analysis of risk factors and outcomes for delayed gastric emptying following pancreaticoduodenectomy: a single center experience of 492 cases]

Objective: To evaluate risk factors for delayed gastric emptying(DGE)following pancreaticoduodenectomy(PD). Methods: There were 492 consecutive patients who underwent PD in Pancreas Center, the First Affiliated Hospital with Nanjing Medical University between January 2012 and December 2014 were identified from a prospective database.There were 315 male and 177 female patients with a median age of 60.5 years.Univariate and multivariate analyses were performed to investigate the independent risk factors for clinically relevant DGE(CR-DGE). Results: The overall incidence of DGE was 29.5%, with Grade B and C occurring at 4.3% and 5.9%, respectively.In multivariate analysis, pancreatic duct diameter less than 3 mm(OR=1.888, P=0.042), pylorus-preserving pancreaticoduodenectomy(OR=2.627, P=0.005) and clinically relevant postoperative pancreatic fistula(OR=2.740, P=0.007) were independently associated with CR-DGE.Other main complications such as postoperative pancreatic fistula, pyoperitoneum, intraabdominal infection were also associated with the severity of DGE(χ(2)=21.360, 14.422, 14.378; P=0.011, 0.002, 0.002). DGE patients had a significantly prolonged postoperative length of stay(31(24-41)d vs. 13(11-17)d) and increased medical cost((122 367.5±66 068.3)yuan vs. (78 200.7±27 043.9)yuan)(both P<0.01). Conclusions: Small pancreatic duct, underwent pylorus-preserving pancreaticoduodenectomy and suffered postoperative pancreatic fistula might indicate a high risk of CR-DGE.

The 3C protease of enterovirus A71 counteracts the activity of host zinc-finger antiviral protein (ZAP)

Enterovirus A71 (EV-A71) is a positive-strand RNA virus that causes hand-foot-mouth disease and neurological complications in children and infants. Although the underlying mechanisms remain to be further defined, impaired immunity is thought to play an important role. The host zinc-finger antiviral protein (ZAP), an IFN-stimulated gene product, has been reported to specifically inhibit the replication of certain viruses. However, whether ZAP restricts the infection of enteroviruses remains unknown. Here, we report that EV-A71 infection upregulates ZAP mRNA in RD and HeLa cells. Moreover, ZAP overexpression rendered 293 T cells resistant to EV-A71 infection, whereas siRNA-mediated depletion of endogenous ZAP enhanced EV-A71 infection. The EV-A71 infection stimulated site-specific proteolysis of two ZAP isoforms, leading to the accumulation of a 40 kDa N-terminal ZAP fragment in virus-infected cells. We further revealed that the 3C protease (3Cpro) of EV-A71 mediates ZAP cleavage, which requires protease activity. Furthermore, ZAP variants with single amino acid substitutions at Gln-369 were resistant to 3Cpro cleavage, implying that Gln-369 is the sole cleavage site in ZAP. Moreover, although ZAP overexpression inhibited EV-A71 replication, the cleaved fragments did not show this effect. Our results indicate that an equilibrium between ZAP and enterovirus 3Cpro controls viral infection. The findings in this study suggest that viral 3Cpro mediated ZAP cleavage may represent a mechanism to escape host antiviral responses.

[Laparoscopic pancreaticoduodenectomy with a novel artery first and uncinate process first approach through Treitz ligament]

Objective: To explore the clinical effect of a novel artery first and uncinate process first approach for laparoscopic pancreaticoduodenectomy(LPD), emphasizing the left lateral and posterior dissection of uncinate process (UP) via Treitz ligament approach. Methods: From April to November 2016, 18 patients received LPD with a novel approach in Pancreas Center of the First Affiliated Hospital with Nanjing Medical University. All patients were diagnosed as pancreatic head or peri-ampulla tumor, without major vessel invasion nor distant metastasis. For resection, routine caudal view was used in the first step, to dissect the anterior medial border between uncinate process and superior mesenteric vein(SMV). Lymphatic tissues were completely dissected form anterior surface of hepatoduodenal ligament. In the second step, left lateral view with camera from left para-umbilical trocar was used, Treitz ligament was incised, SMA root was exposed. After anticlockwise rotation and retraction of mesentery, the anatomic relationship between SMA trunk, inferior pancreaticoduodenal artery(IPDA), jejunal branch of SMV, and distal part of UP, could be perfectly exposed from left lateral view. SMA was dissected from its root until the position above the uncinate process and duodenum, IPDA was transected, distal part of UP was freed from SMA. In the third step, right lateral view and caudal view were alternatively used; proximal UP mesentery was completely dissected out from SMA root, CA root and posterior surface of hepatoduodenal ligament. Pancreaticoduodenectomy was completed in the forth step after transection of pancreatic neck and common hepatic duct. Results: The SMA root and distal UP were successfully dissected out via Treitz ligament approach in all 18 patients, among them, distal UP was completely excised in 8 patients from left view. Postoperative pathology showed R0 resection rate in 69%. Postoperative complication included intra-abdominal hemorrhage in 1 patient, pancreatic fistula in 7 patients(6 cases with grade A and 1 case with grade B), delayed gastric emptying in 4 patients (2 cases with grade A, 2 cases with grade B). Average postoperative hospital stay was (15.5±6.8)days. Conclusion: The novel artery first and uncinate process first approach through Treitz ligament could help surgeons to completely dissect the full length of meso-pancreas along celiac axis-SMA axis in LPD.

Icariin promotes mouse hair follicle growth by increasing insulin-like growth factor 1 expression in dermal papillary cells

BACKGROUND

Icariin is a major flavonoid isolated from Epimedium spp. leaves (Epimedium Herba), and has multiple pharmacological functions, including anti-angiogenesis, anti-oxidant, anti-inflammatory and immunoprotective effects.

AIM

To investigate whether icariin can stimulate growth of hair follicles in mice and the underlying mechanism.

METHODS

In vitro, the effect of icariin on hair growth was assessed by using a vibrissae hair follicle (VHF) organ-culture model. The proliferation of hair matrix keratinocytes and the expression of insulin-like growth factor (IGF)-1 in follicles were examined by double immunostaining for 5-bromo-2'-deoxyuridine and IGF-1, in the presence or absence of icariin. Dermal papilla cells (DPCs) were cultured and IGF-1 level was measured by reverse transcription-PCR and ELISA after icariin treatment. In vivo, the effect of icariin on hair growth was examined by gavage feeding of icariin to mice whose backs had been depilated, and the conversion of telogen to anagen hair was observed.

RESULTS

Treatment with icariin promoted hair shaft elongation, prolonged the hair cycle growth phase (anagen) in cultured VHFs, and accelerated transition of hair cycle from telogen to anagen phase in the dorsal skin of mice. There was significant proliferation of matrix keratinocytes and an increased level of IGF-1 in cultured VHFs. Moreover, icariin treatment upregulated IGF-1 mRNA expression in DPCs and increased IGF-1 protein content in the conditioned medium of DPCs.

CONCLUSIONS

These results suggest that icariin can promote mouse hair follicle growth via stimulation of IGF-1 expression in DPCs.

Reconstruction with soft tissue free flaps for large defects after the resection of giant facial neurofibroma

Giant facial neurofibroma leads to disfigurement and functional and neurological deficits. Surgical resection is the mainstay of treatment and poses a great challenge to the surgeon with regard to the restoration of the defects arising from tumour resection. The cases of three male and three female patients diagnosed with giant facial neurofibroma, who underwent radical resection and reconstruction with soft tissue free flaps between 2008 and 2015, were analyzed retrospectively. Clinical data including patient sex, age, preoperative embolization of the nutrient artery, volume of blood loss, type and size of flaps used for reconstruction, and complications were recorded. Three of the six patients underwent preoperative embolization of the nutrient artery. The average volume of blood loss was 2850ml. Reconstruction was performed with anterolateral thigh flaps in four patients and latissimus dorsi myocutaneous flaps in two patients. All free flap reconstructions were successful. Partial necrosis of the scalp and wound dehiscence occurred in one patient each. All complications were managed successfully. In conclusion, the soft tissue free flap is a good choice for the coverage of defects after giant facial neurofibroma resection. Multi-disciplinary treatment should be strengthened to minimize the risks of complications, as well as improving quality of life.

Fluctuation Spectroscopy Analysis of Glucose Capped Gold Nanoparticles

In this work, we report the synthesis and biophysical studies carried out on a new kind of biocompatible and very stable gold nanoparticle (GNP) stabilized with glucose through a PEG linker (AuNP-PEG-Glu). The synthetic path was optimized to obtain nanoparticles of controlled sizes. ζ-potential and dynamic light scattering measurements allowed assessment of the nanodimension, dispersity, surface charge, and stability of our GNPs. Confocal microscopy demonstrated qualitatively that glucose molecules are successfully bonded to GNP surfaces. For our study, we selected nanoparticles with diameter in a range that maximizes the internalization efficiency in cells (40 nm). A detailed investigation about the biophysical proprieties of AuNP-PEG-Glu was carried out by means of fluorescence correlation spectroscopy (FCS) and orbital tracking techniques. This work gives new insights about the uptake mechanism of gold nanoparticles capped with glucose molecules.

[The possibility and feasibility of implementation of enhanced recovery after surgery program in pancreatic surgery]

Although the concept of enhanced recovery after surgery(ERAS)had been raised for nearly 20 years, the application of ERAS in pancreatic surgery is still restricted because of great trauma and high incidence of postoperative complications.ERAS have demonstrated significantly accelerated postoperative recovery in pancreatic resections.Large amounts of researches confirmed that using an ERAS protocol in pancreatic surgery could help reduce overall morbidity and shorten postoperative length of hospital stay and reduce in-hospital costs. Systemic standard operating procedure could improve executive ability of the ERAS system, including establishing multi-disciplinary team, making management processes, developing verification regime, guarding against medical risks, increasing patient engagement, setting discharge criteria, improving re-admission system.In conclusion, ERAS can be realized in pancreatic surgery and will get substantial development in future.

Comparison of manganese biodistribution and MR contrast enhancement in rats after intravenous injection of MnDPDP and MnCl2

Purpose: To compare the time course of the MR enhancing properties and biodistri-bution of manganese (Mn) in rats given i.v. Mn dipyridoxyl diphosphate (MnDPDP) or Mn chloride (MnCl2).

Material and Methods: Twenty-four adult rats were injected i.v. with 5 μmol/kg MnDPDP or MnCl2, or with 0.5 ml/kg saline. High resolution T1-weighted MR imaging was performed during early (10 min), mid (2 h) and late (24 h) phases after injection. Mn concentrations in major organs were measured by using an ICP-AES technique, and correlated with MR findings.

Results: Variable degrees of signal enhancement of major organs observed in MR images corresponded with the amount of Mn uptake after injection of MnDPDP or MnCl2. A prominently lower cardiac, pancreatic and hepatic uptake of Mn was seen at 10 min in rats injected with MnDPDP compared with those given MnCl2 and this was reflected in a difference in signal intensity (SI) in the MR images. At 2 h, the Mn content and SI in the major organs were similar with both MnDPDP and MnCl2. An overall Mn clearance was achieved at 24 h without any important organ retention, with kidney excretion of Mn seen only with MnDPDP.

Conclusion: With both MnDPDP and MnCl2, the Mn uptake correlates with the SI enhancement in tissues. The reduced initial cardiac uptake of Mn after MnDPDP treatment compared to MnCl2 may account for the favourable cardiovascular safety of the contrast agent. These data contribute to an understanding of SI enhancement by MnDPDP, and are consistent with other studies showing that at a dose of 5 μmol/kg, MnDPDP can be safely used as a potent MR organ-specific contrast agent.

Leptin changes differentiation fate and induces senescence in chondrogenic progenitor cells

Body weight is a component of the mechanical theory of OA (osteoarthritis) pathogenesis. Obesity was also found to be a risk factor for digital OA involving non-weight-bearing joints, which suggested that metabolism influences the occurrence and progression of OA. The metabolic origin of OA has been partially attributed to the involvement of adipokines, such as leptin, the levels of which are significantly and positively correlated with cartilage degeneration in OA patients. However, the mechanisms by which leptin-induced cartilage degeneration occurs are poorly understood. The discovery of chondrogenic progenitor cells (CPCs) opened up new opportunities for investigation. Investigating the effects of leptin on differentiation and proliferation in CPCs would increase our understanding of the roles played by leptin in the aetiology and development of OA. Here, CPCs were harvested using single-cell sorting from rat cartilage tissues to obtain mesenchymal stem-like cells, which possess clonogenicity, proliferation and stemness. High doses of leptin decreased the ability of the CPCs to migrate, inhibited their chondrogenic potential and increased their osteogenic potential, suggesting that leptin changes differentiation fates in CPCs. High doses of leptin induced cell cycle arrest and senescence in CPCs by activating the p53/p21 pathway and inhibiting the Sirt1 pathway. Inhibiting the Sirt1 pathway accelerated cartilage senescence in knockout (KO) mice. Activating the leptin pathway induced higher Ob-Rb expression and was significantly correlated with cartilage degeneration (lower levels of Coll-2) and tissue senescence (higher levels of p53/p21 and lower levels of Sirt1) in OA patients, suggesting that leptin-induced CPCs senescence contributes to the development of OA. Taken together, our results reveal new links between obesity and cartilage damage that are induced by leptin-mediated effects on cell behaviour and senescence.

Correlations Between Echocardiographic Systolic and Diastolic Function with Cardiac Catheterization in Biventricular Congenital Heart Patients

Newer echocardiographic techniques may allow for more accurate assessment of left ventricular (LV) function. Adult studies have correlated these echocardiographic measurements with invasive data, but minimal data exist in the pediatric congenital heart population. Purpose of this study was to evaluate which echocardiographic measurements correlated best with LV systolic and diastolic catheterization parameters. Patients with two-ventricle physiology who underwent simultaneous echocardiogram and cardiac catheterization were included. Images were obtained in the four-chamber view. LV systolic echocardiographic data included ejection fraction, displacement, tissue Doppler imaging (TDI) s' wave, global longitudinal strain, and strain rate (SR) s' wave. Diastolic echocardiographic data included mitral E and A waves, TDI e' and a' waves, and SRe' and SRa' waves. E/TDI e', TDI e'/TDI a', E/SRe', and SRe'/SRa' ratios were also calculated. Catheterization dP/dt was used as a marker for systolic function, and LV end-diastolic pressure (EDP) was used as a marker for diastolic function. Correlations of the echocardiographic and catheterization values were performed using Pearson correlation. Twenty-nine patients were included (14 females, 15 males). Median age at catheterization was 3.4 years (0.04-17.4 years). dP/dt was 1258 ± 353 mmHg/s, and LVEDP was 10.8 ± 2.4 mmHg. There were no significant correlations between catheterization dP/dt and systolic echocardiographic parameters. LVEDP correlated significantly with SRe' (r = -0.4, p = 0.03), SRa' (r = -0.4, p = 0.03), and E/SRe' (r = 0.5, p = 0.004). In pediatric congenital heart patients, catheterization dP/dt did not correlate with echocardiographic measurements of LV systolic function. Further studies are needed to determine which echocardiographic parameter best describes LV systolic function in this population. Strain rate analysis significantly correlated with LVEDP. Strain rate analysis should be considered as an alternative method to estimate LVEDP in this patient population.

Thickness-induced structural phase transformation of layered gallium telluride

We report a spontaneous phase transformation of GaTe, occurring when the bulk is exfoliated to a few layers. The results demonstrate the crucial role of interlayer interactions in the structural stability.

Four cytotoxic annonaceous acetogenins from the seeds of Annona squamosa

Four new annonaceous acetogenins (ACGs), squamocin-I (1), II (2) and III (3) and squamoxinone-D (4), together with seven known ACGs (5-11), were isolated from the seeds of Annona squamosa. The structures of all isolates were elucidated and characterised by spectral and chemical methods. Compounds 1-4 were evaluated for their cytotoxicities against Hep G2, SMMC 7721, BEL 7402, BGC 803 and H460 human cancer cell lines. Compound 1 exhibited better potent activity than the positive compound and compound 3 shows selectively cytotoxical activity against H460 with IC50 values of 0.0492 μg/ml.

A simple and rapid model for hair-follicle regeneration in the nude mouse

BACKGROUND

Methods for hair-follicle regeneration are important tools for investigating signalling and cytokines during hair-follicle morphogenesis and cycling. Several animal models for hair reconstitution have been established; however, these models have several shortcomings.

AIM

To develop a simple and rapid model for hair induction in nude mouse.

METHODS

We designed an improved flap model (IFM) for hair regeneration based on the existing flap assay. Histological sections and scanning electron microscopy were used to evaluate the regenerated hair. The fates of grafted cells were traced by fluorescence. The time required for hair induction was analysed and compared.

RESULTS

IFM produced a large number of normal hairs, and the time required for hair induction using IFM was 20.67 ± 0.67 days, compared with 29.33 ± 0.67 days for the traditional flap assay.

CONCLUSIONS

The time required for hair regeneration is considerably shortened with IFM. We speculate that this is due to increased blood supply at the transplantation sites.

Somatostatin receptor-mediated suppression of gabaergic synaptic transmission in cultured rat retinal amacrine cells

Somatostatin (SRIF) modulates neurotransmitter release by activating the specific receptors (sst1-sst5). Our previous study showed that sst5 receptors are expressed in rat retinal GABAergic amacrine cells. Here, we investigated modulation of GABA release by SRIF in cultured amacrine cells, using patch-clamp techniques. The frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in the amacrine cells was significantly reduced by SRIF, which was partially reversed by BIM 23056, an sst5 receptor antagonist, and was further rescued by addition of CYN-154806, an sst2 receptor antagonist. Both nimodipine, an L-type Ca2+ channel blocker, and ω-conotoxin GVIA, an N-type Ca2+ channel blocker, suppressed the sIPSC frequency, and in the presence of nimodipine and ω-conotoxin GVIA, SRIF failed to further suppress the sIPSC frequency. Extracellular application of forskolin, an activator of adenylate cyclase, increased the sIPSC frequency, while the membrane permeable protein kinase A (PKA) inhibitor Rp-cAMP reduced it, and in the presence of Rp-cAMP, SRIF did not change sIPSCs. However, SRIF persisted to suppress the sIPSCs in the presence of KT5823, a protein kinase G (PKG) inhibitor. Moreover, pre-incubation with Bis IV, a protein kinase C (PKC) inhibitor, or pre-application of xestospongin C, an inositol 1,4,5-trisphosphate receptor (IP3R) inhibitor, SRIF still suppressed the sIPSC frequency. All these results suggest that SRIF suppresses GABA release from the amacrine cells by inhibiting presynaptic Ca2+ channels, in part through activating sst5/sst2 receptors, a process that is mediated by the intracellular cAMP-PKA signaling pathway.

Association analysis of the IL2RA gene with alopecia areata in a Chinese population

BACKGROUND

Interleukin-2 receptor subunit alpha (IL2RA) is highly expressed on CD4+CD25+ regulatory T cells and is important for immune homeostasis and the suppression of autoimmune responses. It has been suggested that the single nucleotide polymorphism in IL2RA may affect the pathogenesis of alopecia areata (AA).

OBJECTIVE

Our aim was to investigate the link between IL2RA polymorphism and AA in a Chinese population.

METHODS

We examined 427 patients and 430 controls in this study. The rs3118470 polymorphism was evaluated using high-resolution melting analysis and direct sequencing.

RESULTS

The prevalence of the C/C, T/C and T/T genotypes was 16.2, 48.2 and 35.6%, respectively. The genotype distribution and allele frequencies were significantly different between AA and control subjects (p < 0.0001). The C allele frequency was significantly higher in the AA group (p < 0.0001), and the frequencies of C allele and C/C genotype were higher in the patients with family history (p = 0.034; p < 0.0001).

CONCLUSIONS

The rs3118470 single nucleotide polymorphism of IL2RA may be a genetic marker to assess the risk of AA in a Chinese population.

Suppression of outward K⁺ currents by WIN55212-2 in rat retinal ganglion cells is independent of CB1/CB2 receptors

Cannabinoid CB1 receptor (CB1R) signaling system is extensively distributed in the vertebrate retina. Activation of CB1Rs regulates a variety of functions of retinal neurons through modulating different ion channels. In the present work we studied effects of this receptor signaling on K(+) channels in retinal ganglion cells by patch-clamp techniques. The CB1R agonist WIN55212-2 (WIN) suppressed outward K(+) currents in acutely isolated rat retinal ganglion cells in a dose-dependent manner, with an IC50 of 4.7 μM. We further showed that WIN mainly suppressed the tetraethylammonium (TEA)-sensitive K(+) current component. While CB1Rs were expressed in rat retinal ganglion cells, the WIN effect on K(+) currents was not blocked by either AM251/SR141716, specific CB1R antagonists, or AM630, a selective CB2R antagonist. Consistently, cAMP-protein kinase A (PKA) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathways were unlikely involved in the WIN-induced suppression of the K(+) currents because both PKA inhibitors H-89/Rp-cAMP and MAPK/ERK1/2 inhibitor U0126 failed to block the WIN effects. WIN-induced suppression of the K(+) currents was not observed when WIN was intracellularly applied. Furthermore, an endogenous ligand of the cannabinoid receptor anandamide, the specific CB1R agonist ACEA and the selective CB2R agonist CB65 also suppressed the K(+) currents, and the effects were not blocked by AM251/SR141716 or AM630 respectively. All these results suggest that the WIN-induced suppression of the outward K(+) currents in rat retinal ganglion cells, thereby regulating the cell excitability, were not through CB1R/CB2R signaling pathways.

Next-generation small RNA sequencing for microRNAs profiling in Apis mellifera: comparison between nurses and foragers

MicroRNAs (miRNAs) are endogenous small non-coding RNAs regulating gene expression in animals and plants. To find some differentially expressed miRNAs that may be associated with age-dependent behavioural changes in honey bees (Apis mellifera), we applied next-generation high-throughput sequencing technology to detect small RNAs in nurses and foragers. Our results showed that both nurses and foragers had a complicated small RNA population, and the length of small RNAs varied, 22 nucleotides being the predominant length. Combining deep sequencing and bioinformatic analysis, we discovered that nine known miRNAs were significantly different between nurses and foragers (P < 0.01; absolute value of fold-change ≥ 1). Some of their target genes were related to neural function. Moreover, 67 novel miRNAs were identified in nurses and foragers. Ame-miR-31a and ame-miR-13b were further validated using quantitative reverse-transcription PCR assays. The present study provides new information on the miRNA abundance of honey bees, and enhances our understanding of miRNA function in the regulation of honey bee development.

Vasohibin 2 is transcriptionally activated and promotes angiogenesis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) typically relies on angiogenesis for its malignant behavior, including growth and metastasis. Vasohibin 2 (VASH2) was previously identified as an angiogenic factor, but its role in tumorigenesis is unknown. Using quantitative PCR and western blot analyses, we found that VASH2 is overexpressed in HCC cells and tissues. Using chromatin immunoprecipitation, we detected histone modifications at the putative VASH2 promoter, with increased H3K4 trimethylation and H3 acetylation and decreased H3K27 trimethylation, suggesting that epigenetic mechanisms are responsible for the deregulated VASH2 transcription in HCC. Knockdown of VASH2 via siRNA inhibited the proliferation of the hepatoma cell lines by delaying cell cycle progression and increasing apoptosis. Importantly, we found VASH2 secreted in the culture supernatant, and co-expression of its secretory chaperone small vasohibin-binding protein (SVBP) further enhanced VASH2 secretion. The supernatant from HepG2 cells expressing VASH2 enhanced the proliferation, migration and tube formation of human umbilical vein endothelial cells, and knockdown of VASH2 significantly inhibited these effects. In an in vivo study using a nude mouse model, we found that exogenous VASH2 significantly contributed to tumor growth, microvessel density and hemoglobin concentration in the tumors. Further analyses showed that the VASH2-mediated increase in the transcription of fibroblast growth factor-2, vascular endothelial growth factor and vasohibin 1 may be the mechanism underlying these effects. Taken together, these data indicate that VASH2 is abnormally expressed in HCC cells as a result of histone modifications and that VASH2 contributes to the angiogenesis in HCC via an SVBP-mediated paracrine mechanism. These results indicate a novel and important role for VASH2 in HCC angiogenesis and malignant transformation.

Removal of uracil by uracil DNA glycosylase limits pemetrexed cytotoxicity: overriding the limit with methoxyamine to inhibit base excision repair

Uracil DNA glycosylase (UDG) specifically removes uracil bases from DNA, and its repair activity determines the sensitivity of the cell to anticancer agents that are capable of introducing uracil into DNA. In the present study, the participation of UDG in the response to pemetrexed-induced incorporation of uracil into DNA was studied using isogenic human tumor cell lines with or without UDG (UDG(+/+)/UDG(-/-)). UDG(-/-) cells were very sensitive to pemetrexed. Cell killing by pemetrexed was associated with genomic uracil accumulation, stalled DNA replication, and catastrophic DNA strand breaks. By contrast, UDG(+/+) cells were >10 times more resistant to pemetrexed due to the rapid removal of uracil from DNA by UDG and subsequent repair of the resultant AP sites (abasic sites) via the base excision repair (BER). The resistance to pemetrexed in UDG(+/+) cells could be reversed by the addition of methoxyamine (MX), which binds to AP sites and interrupts BER pathway. Furthermore, MX-bound AP sites induced cell death was related to their cytotoxic effect of dual inactivation of UDG and topoisomerase IIα, two genes that are highly expressed in lung cancer cells in comparison with normal cells. Thus, targeting BER-based therapy exhibits more selective cytotoxicity on cancer cells through a synthetic lethal mechanism.

Simulating microbial systems: addressing model uncertainty/incompleteness via multiscale and entropy methods

Most systems of interest in the natural and engineering sciences are multiscale in character. Typically available models are incomplete or uncertain. Thus, a probabilistic approach is required. We present a deductive multiscale approach to address such problems, focusing on virus and cell systems to demonstrate the ideas. There is usually an underlying physical model, all factors in which (e.g., particle masses, charges, and force constants) are known. For example, the underlying model can be cast in terms of a collection of N-atoms evolving via Newton's equations. When the number of atoms is 10(6) or more, these physical models cannot be simulated directly. However, one may only be interested in a coarse-grained description, e.g., in terms of molecular populations or overall system size, shape, position, and orientation. The premise of this chapter is that the coarse-grained equations should be derived from the underlying model so that a deductive calibration-free methodology is achieved. We consider a reduction in resolution from a description for the state of N-atoms to one in terms of coarse-grained variables. This implies a degree of uncertainty in the underlying microstates. We present a methodology for modeling microbial systems that integrates equations for coarse-grained variables with a probabilistic description of the underlying fine-scale ones. The implementation of our strategy as a general computational platform (SimEntropics™) for microbial modeling and prospects for developments and applications are discussed.

Clinical correlates of white matter blood flow perfusion changes in Sturge-Weber syndrome: a dynamic MR perfusion-weighted imaging study

BACKGROUND AND PURPOSE

Low brain tissue perfusion due to abnormal venous drainage is thought to be a central mechanism of brain damage in SWS. Here, HR-PWI was used to quantify WM perfusion abnormalities and to correlate these with brain atrophy and clinical variables.

MATERIALS AND METHODS

Fourteen children (age range, 0.8-10.0 years) with unilateral SWS underwent MR imaging examinations, including HR-PWI. rCBV, rCBF, and MTT in the affected WM and in contralateral homotopic WM were measured. AI for each perfusion parameter was correlated with age, brain atrophy, and motor and seizure variables as well as IQ.

RESULTS

Increased perfusion was seen in the affected hemisphere in 5 children and decreased perfusion in 9 children. Brain atrophy was more severe in the low-perfusion group (P = .01) and was related to both CBF-AI and CBV-AI (r = -0.69, P = .007; r = -0.64, P = .014, respectively). Older children had lower CBV values on the affected side (r = -0.62, P = .02). Longer duration of epilepsy was related to lower CBF (more negative CBF-AI, r = -0.58, P = .03) and low CBV (r = -0.55, P = .04) on the affected side. Lower perfusion was associated with more frequent seizures (rCBF-AI: r = -0.56, P = .04; rCBV-AI: r = -0.63, P = .02).

CONCLUSIONS

Increased perfusion in the affected cerebral WM may indicate an early stage of SWS without severe brain atrophy. Decreased perfusion is associated with frequent seizures, long duration of epilepsy, and brain atrophy.

Increased serum potassium affects renal outcomes: a post hoc analysis of the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) trial

AIMS/HYPOTHESIS

To assess the effect of an angiotensin receptor blocker (ARB) on serum potassium and the effect of a serum potassium change on renal outcomes in patients with type 2 diabetes and nephropathy.

METHODS

We performed a post hoc analysis in patients with type 2 diabetes participating in the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study. Renal outcomes were defined as a composite of doubling of serum creatinine or end-stage renal disease.

RESULTS

At month 6, 259 (38.4%) and 73 (10.8%) patients in the losartan group and 151 (22.8%) and 34 (5.1%) patients in the placebo group had serum potassium ≥5.0 mmol/l and ≥5.5 mmol/l, (p < 0.001), respectively. Losartan was an independent predictor for serum potassium ≥5.0 mmol/l at month 6 (OR 2.8; 95% CI 2.0-3.9). Serum potassium at month 6 ≥ 5.0 mmol/l was in turn associated with increased risk for renal events (HR 1.22; 95% CI 1.00-1.50), independent of other risk factors. Adjustment of the overall treatment effects for serum potassium augmented losartan's renoprotective effect from 21% (6-34%) to 35% (20-48%), suggesting that the renoprotective effects of losartan are offset by its effect on serum potassium.

CONCLUSIONS/INTERPRETATION

In this study, we found that treatment with the ARB losartan is associated with a high risk of increased serum potassium levels, which is in turn associated with an increased risk of renal outcomes in patients with diabetes and nephropathy. Whether additional management of high serum potassium would further increase the renal protective properties of losartan is an important clinical question.

Melatonin inhibits tetraethylammonium-sensitive potassium channels of rod ON type bipolar cells via MT2 receptors in rat retina

By challenging specific receptors, melatonin synthesized and released by photoreceptors regulates various physiological functions in the vertebrate retina. Here, we studied modulatory effects of melatonin on K+ currents of rod-dominant ON type bipolar cells (Rod-ON-BCs) in rat retinal slices by patch-clamp techniques. Double immunofluorescence experiments conducted in isolated cell and retinal section preparations showed that the melatonin MT₂ receptor was expressed in somata, dendrites and axon terminals of rat Rod-ON-BCs. Electrophysiologically, application of melatonin selectively inhibited the tetraethylammonium (TEA)-sensitive K+ current component, but did not show any effect on the 4-aminopyridine (4-AP)-sensitive component. Consistent with the immunocytochemical result, the melatonin effect was blocked by co-application of 4-phenyl-2-propionamidotetralin (4-P-PDOT), a specific MT₂ receptor antagonist. Neither protein kinase A (PKA) nor protein kinase G (PKG) seemed to be involved because both the PKA inhibitor Rp-cAMP and the PKG inhibitor KT5823 did not block the melatonin-induced suppression of the K+ currents. In contrast, application of the phospholipase C (PLC) inhibitor U73122 or the protein kinase C (PKC) inhibitor bisindolylmaleimide IV (Bis IV) eliminated the melatonin effect, and when the Ca²+ chelator BAPTA-containing pipette was used, melatonin failed to inhibit the K+ currents. These results suggest that suppression of the TEA-sensitive K+ current component via activation of MT₂ receptors expressed on rat Rod-ON-BCs may be mediated by a Ca²+-dependent PLC/inositol 1,4,5-trisphosphate (IP₃/PKC signaling pathway.