Involvement of miRNAs in the Differentiation of Human Glioblastoma Multiforme Stem-Like Cells

Glioblastoma multiforme (GBM)-initiating cells (GICs) represent a tumor subpopulation with neural stem cell-like properties that is responsible for the development, progression and therapeutic resistance of human GBM. We have recently shown that blockade of NFκB pathway promotes terminal differentiation and senescence of GICs both in vitro and in vivo, indicating that induction of differentiation may be a potential therapeutic strategy for GBM. MicroRNAs have been implicated in the pathogenesis of GBM, but a high-throughput analysis of their role in GIC differentiation has not been reported. We have established human GIC cell lines that can be efficiently differentiated into cells expressing astrocytic and neuronal lineage markers. Using this in vitro system, a microarray-based high-throughput analysis to determine global expression changes of microRNAs during differentiation of GICs was performed. A number of changes in the levels of microRNAs were detected in differentiating GICs, including over-expression of hsa-miR-21, hsa-miR-29a, hsa-miR-29b, hsa-miR-221 and hsa-miR-222, and down-regulation of hsa-miR-93 and hsa-miR-106a. Functional studies showed that miR-21 over-expression in GICs induced comparable cell differentiation features and targeted SPRY1 mRNA, which encodes for a negative regulator of neural stem-cell differentiation. In addition, miR-221 and miR-222 inhibition in differentiated cells restored the expression of stem cell markers while reducing differentiation markers. Finally, miR-29a and miR-29b targeted MCL1 mRNA in GICs and increased apoptosis. Our study uncovers the microRNA dynamic expression changes occurring during differentiation of GICs, and identifies miR-21 and miR-221/222 as key regulators of this process.     

Microarray Data Reveal Relationship between Jag1 and Ddr1 in Mouse Liver

Alagille syndrome is an autosomal dominant disorder involving bile duct paucity and cholestasis in addition to cardiac, skeletal, ophthalmologic, renal and vascular manifestations. Mutations in JAG1, encoding a ligand in the Notch signaling pathway, are found in 95% of patients meeting clinical criteria for Alagille syndrome. In order to define the role of Jag1 in the bile duct developmental abnormalities seen in ALGS, we previously created a Jag1 conditional knockout mouse model. Mice heterozygous for the Jag1 conditional and null alleles demonstrate abnormalities in postnatal bile duct growth and remodeling, with portal expansion and increased numbers of malformed bile ducts. In this study we report the results of microarray analysis and identify genes and pathways differentially expressed in the Jag1 conditional/null livers as compared with littermate controls. In the initial microarray analysis, we found that many of the genes up-regulated in the Jag1 conditional/null mutant livers were related to extracellular matrix (ECM) interactions, cell adhesion and cell migration. One of the most highly up-regulated genes was Ddr1, encoding a receptor tyrosine kinase (RTK) belonging to a large RTK family. We have found extensive co-localization of Jag1 and Ddr1 in bile ducts and blood vessels in postnatal liver. In addition, co-immunoprecipitation data provide evidence for a novel protein interaction between Jag1 and Ddr1. Further studies will be required to define the nature of this interaction and its functional consequences, which may have significant implications for bile duct remodeling and repair of liver injury.     

Variation in hippocampal glial cell numbers in food‐caching birds from different climates

Enhancements to memory are associated with enhanced neural structures that support those capabilities. A great deal of work has examined this relationship in the context of natural variation in spatial memory capability and hippocampal (Hp) structure. Most studies have focused on volumetric and neuron measures, but have seldom examined the role of glial cells. Once considered involved only in supportive functions associated with neurons, the importance of glial cells in cognitive processes, including memory, is gaining more attention. Building upon our previous study on the relationship between the brain, memory, and environmental severity in food‐caching birds, we compared the total number of Hp glial cells in wild‐sampled and in lab‐reared (common garden) black‐capped chickadees (Poecile atricapillus) originating from two different environmental extremes. We found that birds from more harsh climate tended to have significantly more Hp glial cells than those from more mild climate and that lab‐reared chickadees had significantly fewer Hp glial cells compared to the wild‐sampled birds. These results suggest that population differences in glial numbers may be controlled, at least in part, by heritable mechanisms, but glial numbers appear to be additionally regulated by an individual's environment. The pattern of Hp glial cell abundance among our treatment groups closely followed that of the Hp volume, suggesting that Hp glial cell number may be associated with the Hp volume. Unlike Hp neurons, however, the number of Hp glial cells may be, at least in part, affected by an individual's experiences and environment. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 480–485, 2013     

Soluble CD40 Ligand Stimulates the Pro-Angiogenic Function of Peripheral Blood Angiogenic Outgrowth Cells via Increased Release of Matrix Metalloproteinase-9

The role of endothelial progenitor cells in vascular repair is related to their incorporation at sites of vascular lesions, differentiation into endothelial cells, and release of various angiogenic factors specifically by a subset of early outgrowth endothelial progenitor cells (EOCs). It has been shown that patients suffering from cardiovascular disease exhibit increased levels of circulating and soluble CD40 ligand (sCD40L), which may influence the function of EOCs. We have previously shown that the inflammatory receptor CD40 is expressed on EOCs and its ligation with sCD40L impairs the anti-platelet function of EOCs. In the present study, we aimed at investigating the effect of sCD40L on the function of EOCs in endothelial repair. Human peripheral blood mononuclear cell-derived EOCs express CD40 and its adaptor proteins, the tumor necrosis factor receptor-associated factors; TRAF1, TRAF2 and TRAF3. Stimulation of EOCs with sCD40L increased the expression of TRAF1, binding of TRAF2 to CD40 and phosphorylation of p38 mitogen activated protein kinase (MAPK). In an in vitro wound healing assay, stimulation of EOCs with sCD40L increased the release of matrix metalloproteinase 9 (MMP-9) in a concentration-dependent manner and significantly enhanced the angiogenic potential of cultured human umbilical vein endothelial cells (HUVECs). Inhibition of p38 MAPK reversed sCD40L-induced MMP-9 release by EOCs, whereas inhibition of MMP-9 reversed their pro-angiogenic effect on HUVECs. This study reveals the existence of a CD40L/CD40/TRAF axis in EOCs and shows that sCD40L increases the pro-angiogenic function of EOCs on cultured HUVECs by inducing a significant increase in MMP-9 release via, at least, the p38 MAPK signaling pathway.     

Clinical Characteristics Associated with Borrelia burgdorferi Sensu Lato Skin Culture Results in Patients with Erythema Migrans

Clinical characteristics associated with isolation of Borrelia burgdorferi sensu lato from skin have not been fully evaluated. To gain insight into predictors for a positive EM skin culture, we compared basic demographic, epidemiologic, and clinical data in 608 culture-proven and 501 culture-negative adult patients with solitary EM. A positive Borrelia spp. skin culture was associated with older age, a time interval of >2 days between tick bite and onset of the skin lesion, EM ≥5 cm in diameter, and location of the lesion on the extremities, whereas several other characteristics used as clinical case definition criteria for the diagnosis of EM (such as tick bite at the site of later EM, information on expansion of the skin lesion, central clearing) were not. A patient with a 15-cm EM lesion had almost 3-fold greater odds for a positive skin culture than patients with a 5-cm lesion. Patients with a free time interval between the tick bite and onset of EM had the same probability of a positive skin culture as those who did not recall a tick bite (OR=1.02); however, the two groups had >3-fold greater odds for EM positivity than patients who reported a tick bite with no interval between the bite and onset of the lesion. In conclusion, several yet not all clinical characteristics used in EM case definitions were associated with positive Borrelia spp. skin culture. The findings are limited to European patients with solitary EM caused predominantly by B. afzelii but may not be valid for other situations.     

Tailoring Absorption in Metal Gratings with Resonant Ultrathin Bridges

We present a theoretical analysis of the effects of short range surface plasmon polariton excitation on subwavelength bridges in metal gratings. We show that localized resonances in thin metal bridges placed within the slit of a free-standing silver grating dramatically modify transmission spectra and boost absorption regardless of the periodicity of the grating. Additionally, the interference of multiple localized resonances makes it possible to tailor the absorption properties of ultrathin gratings, regardless of the apertures’ geometrical size. This tunable, narrow band, enhanced–absorption mechanism triggered by resonant, short-range surface plasmon polaritons may also enhance nonlinear optical processes like harmonic generation, in view of the large third-order susceptibility of metals.     

Invasive interactions: can Argentine ants indirectly increase the reproductive output of a weed?

The direct and indirect interactions of invasive ants with plants, insect herbivores, and Hemiptera are complex. While ant and Hemiptera interactions with native plants have been well studied, the effects of invasive ant–scale insect mutualisms on the reproductive output of invasive weeds have not. The study system consisted of Argentine ants (Linepithema humile), boneseed (Chrysanthemoides monilifera monilifera), and sap-sucking scale insects (Hemiptera: Saissetia oleae and Parasaissetia nigra), all of which are invasive in New Zealand. We examined the direct and indirect effects of Argentine ants on scale insects and other invertebrates (especially herbivores) and on plant reproductive output. Argentine ants spent one-third of their time specifically associated with scale insects in tending behaviours. The invertebrate community was significantly different between uninfested and infested plants, with fewer predators and herbivores on ant-infested plants. Herbivore damage was significantly reduced on plants with Argentine ants, but sooty mould colonisation was greater where ants were present. Herbivore damage increased when ants were excluded from plants. Boneseed plants infested with Argentine ants produced significantly more fruits than plants without ants. The increase in reproductive output in the presence of ants may be due to increased pollination as the result of pollinators being forced to relocate frequently to avoid attack by ants, resulting in an increase in pollen transfer and higher fruit/seed set. The consequences of Argentine ant invasion can be varied; not only does their invasion have consequences for maintaining biodiversity, ant invasion may also affect weed and pest management strategies.     

Evaluation of Relapse-Free Survival in T3N0 Colon Cancer: The Role of Chemotherapy,a Multicentric Retrospective Analysis

Background

Adjuvant chemotherapy (AC) in Stage II Colon Cancer (CC) is still under debate. Choice should be based on patients and disease characteristics. According to guidelines AC should be considered in high-risk T3N0 patients. No data are available for better option in low-risk patients. The aim of the study is to retrospectively evaluate relapse-free survival (RFS) and disease-free survival (DFS) according to treatment received in T3N0 CC.

Methods

RFS and DFS are evaluated with Kaplan-Meier method. Multivariate Cox proportional hazard model was developed using stepwise regression, enter limit and remove limit were p = 0.10 and p = 0.15, respectively.

Results

834 patients with T3N0 CC were recruited. Median age was 69 (29–93), M/F 463/371, 335 low-risk patients (40.2%), 387 high-risk (46.4%), 112 unknown (13.4%); 127 (15.2%) patients showed symptoms at diagnosis. Median sampled lymph nodes were 15 (1–76); 353 (42.3%) patients were treated with AC. Median follow up was 5 years (range 3–24). The 5-years RFS was 78.4% and the 5-years DFS was 76.7%. At multivariate analysis symptoms, lymph nodes, and adjuvant chemotherapy were prognostic factors for RFS. AC is prognostic factor for all endpoints.In low-risk group 5-years RFS was 87.3% in treated patients and 74.7% in non-treated patients (p 0.03); in high-risk group was respectively 82.7% and 71.4% (p 0.005).

Conclusions

Data confirmed the role of known prognostic factors and suggest the relevance of adjuvant chemotherapy also in low-risk stage II T3N0 CC patients. However, the highest risk in low-risk subgroup should be identified to be submitted to AC.