The role of fibroblast Tiam1 in tumor cell invasion and metastasis

The co-evolution of tumors and their microenvironment involves bidirectional communication between tumor cells and tumor-associated stroma. Various cell types are present in tumor-associated stroma, of which fibroblasts are the most abundant. The Rac exchange factor Tiam1 is implicated in multiple signaling pathways in epithelial tumor cells and lack of Tiam1 in tumor cells retards tumor growth in Tiam1 knock-out mouse models. Conversely, tumors arising in Tiam1 knock-out mice have increased invasiveness. We have investigated the role of Tiam1 in tumor-associated fibroblasts as a modulator of tumor cell invasion and metastasis, using retroviral delivery of short hairpin RNA to suppress Tiam1 levels in three different experimental models. In spheroid co-culture of mammary epithelial cells and fibroblasts, Tiam1 silencing in fibroblasts led to increased epithelial cell outgrowth into matrix. In tissue-engineered human skin, Tiam1 silencing in dermal fibroblasts led to increased invasiveness of epidermal keratinocytes with premalignant features. In a model of human breast cancer in mice, co-implantation of mammary fibroblasts inhibited tumor invasion and metastasis, which was reversed by Tiam1 silencing in co-injected fibroblasts. These results suggest that stromal Tiam1 may play a role in modulating the effects of the tumor microenvironment on malignant cell invasion and metastasis. This suggests a set of pathways for further investigation, with implications for future therapeutic targets.

Distinct host-related dendritic cell responses during the early stage of Plasmodium yoelii infection in susceptible and resistant mice

The diverse outcomes of experimental murine infection with Plasmodium parasites, ranging from spontaneous cure to death, depend largely on the establishment of an effective Th1 immune response during the early stages of infection. However, the molecular and cellular factors responsible for the induction and regulation of this response are poorly understood. As immunity is initiated by dendritic cells (DCs), we compared their phenotype and function during the early stages of infection with Plasmodium yoelii 17XL (P.y 17XL) strain in susceptible (BALB/c) and resistant (DBA/2) mice. Resistant DBA/2 mice developed a greater number of myeloid (CD11c(+)CD11b(+)) and mature DCs, which were fully functional and capable of secreting IL-12p40. In contrast, susceptible BALB/c mice produced more plasmacytoid (CD11c(+)CD45R/B220(+)) and less mature DCs, resulting in high levels of IL-10 and TGF-beta1. In addition, an in vitro experiment confirmed that splenic DCs from the two strains of mice differ in their ability to prime CD4(+)T cells in response to P.y 17XL stimulation. These findings indicate that the subset, the phenotype and the type of inflammatory and anti-inflammatory signals of splenic DCs are critical factors responsible for the discrepancy in the ability to induce or regulate Th1 immune responses in different hosts.

Associations of ATGL gene polymorphisms with chicken growth and fat traits

Adipose triglyceride lipase (ATGL) catalyses the initial step in triglyceride hydrolysis, so the ATGL gene is a candidate for growth and fat traits in chickens. Nine reported single-nucleotide polymorphisms (SNPs) located in 3 exons of the chicken ATGL gene were chosen for genotyping an F2 population. Only 5 SNPs were confirmed for polymorphisms and used for association analyses. The results show that c.531G>A (p.E177Syn) was not associated with any growth and fat traits (P > 0.05), but c.782G>A (p.S261N) was associated with body weight (BW) on days 14, 21, 35, 63, 70, 77, cingulated fat width and abdominal fat pad weight (P < 0.05), and significantly associated with BW on days 42, 49, and 56 (P < 0.01). Significant associations of c.903C>T (p.F301Syn) with BW on days 49 and 77 days and crude protein content of breast muscle (P < 0.05), and c.1164G>A (p.K388Syn) with BW on day 7 (P < 0.05) were also detected. Additionally, c.1069T>C (p.L357Syn) was associated with breast muscle colour (P < 0.05), and significantly associated with crude fat (ether extract) content of breast muscle (P < 0.01). Thus the missense SNP of c.782G>A (p.S261N) was significantly associated with the largest number of chicken growth and fat traits in this study.

White matter microstructure changes in the thalamus in Parkinson disease with depression: A diffusion tensor MR imaging study

BACKGROUND AND PURPOSE

Depression occurs frequently in PD; however the neural basis of depression in PD remains unclear. The aim of this study was to characterize possible depression-related white matter microstructural changes in the thalamus of patients with DPD compared with those with NDPD.

MATERIALS AND METHODS

FA and MD maps from DTI were obtained in 14 patients with DPD and 18 patients with NDPD. Region-of-interest-guided VBA was conducted on the FA maps to detect possible microstructural differences in the thalamus between these 2 patient groups. Moreover, mean FA and MD in regions with a detected difference were compared between DPD and NDPD groups, and correlations between diffusion quantities and the severity of depression were analyzed.

RESULTS

White matter microstructure differences were found between the patients with DPD and NDPD in the bilateral mediodorsal thalamic regions. In these regions, patients with DPD showed significantly decreased FA values (P < .005) compared with patients with NDPD, and the mean values of FA were negatively correlated with the scores of depression severity (P < .05) for patients with PD. No significant differences of MD were found in the mediodorsal thalamus between these 2 groups.

CONCLUSIONS

Our results provide preliminary evidence that the mediodorsal thalamus may play an important role in depression in PD and suggest a relationship between FA in the mediodorsal thalamus and the presence of depressive symptoms in patients with DPD. These findings may be helpful for further understanding the potential mechanisms of depression in PD.

Assessing sources of inconsistencies in genotypes and their effects on genome-wide association studies with HapMap samples

The discordance in results of independent genome-wide association studies (GWAS) indicates the potential for Type I and Type II errors. We assessed the repeatibility of current Affymetrix technologies that support GWAS. Reasonable reproducibility was observed for both raw intensity and the genotypes/copy number variants. We also assessed consistencies between different SNP arrays and between genotype calling algorithms. We observed that the inconsistency in genotypes was generally small at the specimen level. To further examine whether the differences from genotyping and genotype calling are possible sources of variation in GWAS results, an association analysis was applied to compare the associated SNPs. We observed that the inconsistency in genotypes not only propagated to the association analysis, but was amplified in the associated SNPs. Our studies show that inconsistencies between SNP arrays and between genotype calling algorithms are potential sources for the lack of reproducibility in GWAS results.

Basal ganglia surface morphology and the effects of stimulant medications in youth with attention deficit hyperactivity disorder

OBJECTIVE

Disturbances in the basal ganglia portions of cortico-striato-thalamo-cortical circuits likely contribute to the symptoms of attention deficit hyperactivity disorder (ADHD). The authors examined the morphologic features of the basal ganglia nuclei (caudate, putamen, and globus pallidus) in children with ADHD.

METHOD

A total of 104 individuals (combined-type ADHD patients: N=47; healthy comparison subjects: N=57), aged 7 to 18 years, were examined in a cross-sectional case-control study using anatomical magnetic resonance imaging. Conventional volumes and the surface morphology for the basal ganglia were measured.

RESULTS

Overall volumes were significantly smaller only in the putamen. Analysis of the morphological surfaces revealed significant inward deformations in each of the three nuclei, localized primarily in portions of these nuclei that are components of limbic, associative, and sensorimotor pathways in the cortico-striato-thalamo-cortical circuits in which these nuclei reside. The more prominent these inward deformations were in the patient group, the more severe the ADHD symptoms. Surface analyses also demonstrated significant outward deformations of all basal ganglia nuclei in the ADHD children treated with stimulants compared with those ADHD youth who were untreated. These stimulant-associated enlargements were in locations similar to the reduced volumes detected in the ADHD group relative to the comparison group. The outward deformations associated with stimulant medications attenuated the statistical effects of the primary group comparisons.

CONCLUSIONS

These findings potentially represent evidence of anatomical dysregulation in the circuitry of the basal ganglia in children with ADHD and suggest that stimulants may normalize morphological features of the basal ganglia in children with the disorder.

Angiotensin-converting enzyme insertion/deletion polymorphism associated with acute respiratory distress syndrome among caucasians

Studies investigating the association between angiotensin-converting enzyme (ACE) insertion/deletion polymorphisms and the risk of acute respiratory distress syndrome (ARDS) report conflicting results. The objective of the present study was to summarize quantitatively the evidence for such a relationship. Two investigators independently searched the MEDLINE (January 1966 - October 2009) and EMBASE (January 1980 - October 2009) databases. This meta-analysis included six case-control studies, which included 514 ARDS cases and 2619 controls. The combined results based on all studies showed that patients with ARDS had a significantly higher frequency of the ACE deletion/deletion (DD) genotype (odds ratio [OR] 1.56; 95% confidence interval [CI] 1.22, 2.00) than controls. When stratifying for race, no significant differences in genotype distribution were found except that Caucasian patients with ARDS had a significantly higher frequency of the DD genotype (OR 1.65; 95% CI 1.27, 2.13) than controls. This meta-analysis suggests that ACE insertion/deletion polymorphisms may be associated with ARDS among Caucasians.

MEK/ERK and p38 MAPK regulate chondrogenesis of rat bone marrow mesenchymal stem cells through delicate interaction with TGF-beta1/Smads pathway

OBJECTIVES

This study was carried out to reveal functions and mechanisms of MEK/ERK and p38 pathways in chondrogenesis of rat bone marrow mesenchymal stem cells (BMSCs), and to investigate further any interactions between the mitogen-activated protein kinase (MAPK) and transforming growth factor-beta1 (TGF-beta1)/Smads pathway in the process.

MATERIALS AND METHODS

Chondrogenic differentiation of rat BMSCs was initiated in micromass culture, in the presence of TGF-beta1, for 2 weeks. ERK1/2 and p38 kinase activities were investigated by Western Blot analysis. Specific MAPK inhibitors PD98059 and SB20350 were employed to investigate regulatory effects of MEK/ERK and p38 signals on gene expression of chondrocyte-specific markers, and TGF-beta1 downstream pathways of Smad2/3.

RESULTS

ERK1/2 was phosphorylated in a rapid but transient manner, whereas p38 was activated in a slow and sustained way. The two MAPK subtypes played opposing roles in mediating transcription of cartilage-specific genes for Col2alpha and aggrecan. TGF-beta1-stimulated gene expression of chondrogenic regulators, Sox9, Runx2 and Ihh, was also affected by activity of PD98059 and SB203580, to different degrees. However, influences of MAPK inhibitors on gene expression were relatively minor when not treated with TGF-beta1. In addition, gene transcription of Smad2/3 was significantly upregulated by TGF-beta1, but was regulated more subtly by treatment with MAPK inhibitors.

CONCLUSIONS

MAPK subtypes seemed to regulate chondrogenesis with a delicate balance, interacting with the TGF-beta1/Smads signalling pathway.

Higher moments of net proton multiplicity distributions at RHIC

We report the first measurements of the kurtosis (κ), skewness (S), and variance (σ2) of net-proton multiplicity (Np-Np) distributions at midrapidity for Au+Au collisions at square root of s(NN)=19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (μB) between 200 and 20 MeV. Our measurements of the products κσ2 and Sσ, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the square root of s(NN) dependence of κσ2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for μB below 200 MeV.

Three-particle coincidence of the long range pseudorapidity correlation in high energy nucleus-nucleus collisions

We report the first three-particle coincidence measurement in pseudorapidity (Δη) between a high transverse momentum (p⊥) trigger particle and two lower p⊥ associated particles within azimuth |Δϕ|<0.7 in square root of s(NN)=200 GeV d+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range Δη correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured Δη. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

The use of signalling pathway inhibitors and chromatin modifiers for enhancing pluripotency

Pluripotent embryonic stem cells have been isolated from a limited number of species. The new advances with inducing pluripotency in somatic cells have resulted in the generation of pluripotent stem cells while circumventing the need for embryos. In this review we describe the main signalling pathways involved in maintaining pluripotency and inducing differentiation. Inhibition of the signalling pathways involved in differentiation enhances the derivation and cultivation of pluripotent stem cells. Furthermore, we discuss the use of chromatin modifiers to maintain an open chromatin state which is characteristic of pluripotent stem cells, to facilitate the derivation of pluripotent cell lines.

Ceramic thin-film formation on functionalized interfaces through biomimetic processing

Processing routes have been developed for the production of thin ceramic films through precipitation from aqueous solutions. The techniques are based on crystal nucleation and growth onto functionalized interfaces. Surface functionalization routes have been developed by the mimicking of schemes used by organisms to produce complex ceramic composites such as teeth, bones, and shells. High-quality, dense polycrystalline films of oxides, hydroxides, and sulfides have now been prepared from "biomimetic" synthesis techniques. Ceramic films can be synthesized on plastics and other materials at temperatures below 100 degrees C. As a low-temperature process in which water rather than organic solvents is used, this synthesis is environmentally benign. Nanocrystalline ceramics can be produced, sometimes with preferred crystallite orientation. The direct deposition of high-resolution patterned films has also been demonstrated. The process is well suited to the production of organic-inorganic composites.