The LIM protein fhlA is essential for heart chamber development in zebrafish embryos

Four-and-a-half LIM proteins FHL1-3 play important roles in cardiovascular pathophysiology. However, their roles in heart development remain unclear. Here, we report that fhlA, the zebrafish homolog of human FHL1, was found to be expressed around the 22-somite stage. After 24 hpf, expression was restricted to the heart. fhlA knockdown caused an enlarged cardiac chamber phenotype with up-regulated expression of the cardiac markers, but fhlA overexpression reduced the sizes of the cardiac chambers and down-regulated expression of the markers. The morphology associated with the cmlc2, amhc, and vmhc expression patterns at the 22 somite and 24 hpf stages included a broadened domain in embryos lacking fhlA and a smaller domain in embryos overexpressing fhlA. The changes in the sizes of the chambers were attributed to the changes in the number of ventricular and atrial cells. Loss of fhlA caused a longer heart period and pause between heartbeats in M-modes than in controls, but fhlA overexpression caused shorter systolic and diastolic intervals. Abnormal cardiac chambers and physiological function were found to be largely rescued. We also showed the expression of fhlA in the heart to be increased by retinoic acid (RA) and decreased by the RA synthase inhibitor DEAB. Both fhlA and RA signaling caused a phenotype characterized by the morphological alterations in the chamber sizes, suggesting that the role of fhlA in heart development is probably regulated by RA signaling. Taken together, these results showed that fhlA regulates the size of the heart chamber by reducing the number of cardiac cells.

Activation of β-catenin stimulated by mechanical strain and estrogen requires estrogen receptor in mesenchymal stem cells (MSCs)

BACKGROUND AND OBJECTIVES

Mechanical stimulation and hormones act via interconnected signaling pathways to influence the function of bone cells. Estrogen receptor (ER) and β-catenin play important role in bone formation and have implicated in mechanotransduction in bone cells. To investigate the interaction between mechanotransduction and estrogenic signaling in mesenchymal stem cells (MSCs), this study examined the effect of mechanical strain and estrogen on activation of β-catenin in MSCs, and the role of ER in response to mechanical strain and estrogen in MSCs.

MATERIALS AND METHODS

MSCs were exposed to mechanical strain (2%, 1 Hz) and estrogen (100 nM). The ER inhibitor, ICI182,780 was used to assess the role of ER in activation of β-catenin stimulated by mechanical strain and estrogen. Changes of activated β-catenin in the nuclei were determined by immunoflourescent test. The expression of β-catenin was detected by western blotting.

RESULTS

Mechanical strain and estrogen augment, respectively, activation of β-catenin and accumulation of activated β-catenin in the nuclei of MSCs. Combined treatment with estrogen and mechanical strain had higher levels of activated β-catenin than the cells exposed to mechanical strain or estrogen. After MSCs were pre-treated by ICI182,780, the level of activated β-catenin expression induced by mechanical strain or estrogen was depressed. Meanwhile, ICI182,780 blocked effect of combined stimulation on activation of β-catenin in MSCs.

CONCLUSIONS

Our study demonstrates that mechanical strain and estrogen both promote the levels of activated β-catenin in MSCs. Estrogen receptor implicates in activation of β-catenin stimulation by mechanical strain and estrogen in MSCs.

Neuropilin-1 is overexpressed in osteosarcoma and contributes to tumor progression and poor prognosis

AIM

Neuropilin (NRP)-1, a co-receptor for vascular endothelial growth factor (VEGF), plays an important role in angiogenesis and malignant progression of many cancers. However, the involvement of NRP-1 in osteosarcoma is not completely understood. The aim of this study was to investigate the expression pattern and clinical significance of NRP-1 in human osteosarcoma.

METHODS

NRP-1 mRNA and protein expression levels were detected by RT-PCR and Western blot assays, respectively, using 166 pairs of osteosarcoma and noncancerous bone tissues. Then, the association of NRP-1 expression with clinicopathological factors or survival of osteosarcoma patients was further evaluated.

RESULTS

RT-PCR and Western blot assays revealed that NRP-1 expression in osteosarcoma tissues was significantly higher than that in corresponding noncancerous bone tissues at both mRNA and protein levels (both P < 0.001). In addition, high NRP-1 expression more frequently occurred in osteosarcoma tissues with advanced clinical stage (P = 0.006), positive distant metastasis (P = 0.01) and poor response to chemotherapy (P = 0.006). Moreover, osteosarcoma patients with high NRP-1 expression had significantly shorter overall survival and disease-free survival (both P < 0.001) when compared with patients with the low expression of NRP-1. On Cox multivariate analysis, NRP-1 overexpression was an independent and significant prognostic factor to predict poor overall survival and disease-free survival (both P = 0.001).

CONCLUSION

This is the first study to reveal that NRP-1 overexpression may be related to the prediction of metastasis potency, response to chemotherapy and poor prognosis for osteosarcoma patients, suggesting that NRP-1 may serve as a prognostic marker for the optimization of clinical treatments.

Role of mechanical strain and estrogen in modulating osteogenic differentiation of mesenchymal stem cells (MSCs) from normal and ovariectomized rats

Bone's adaptability to loading depends upon the process of bone remodeling. This adaptive mechanism is restricted in postmenopausal osteoporosis. Differentiation of mesenchymal stem cells (MSCs) is crucial to bone remodeling and regeneration. It is well accepted that mechanical loading influences the fate of MSC differentiation. The aim of this study was to explore the possible restricted mechanism in osteoporotic condition, through investigating response of MSCs from both sham-operated and ovariectomized rats. MSCs were exposed to estrogen and mechanical strain (2%, 1Hz, 6h/day) for 3 days. Osteogenic differentiation and β-catenin protein in MSCs were examined. Exposure to estrogen and mechanical strain alone enhanced expression of Runx2 (Cbfα1), type I collagen (ColI) and activated β-catenin protein in MSCs from both sham-operated and OVX rats. MSCs from both sham-operated and OVX rats stimulated with both mechanical strain and estrogen had higher expression of osteogenic genes and activated β-catenin protein than these cells exposed to estrogen and mechanical strain alone. Osteoporotic MSCs had lower expression of osteogenic genes and protein in the absence and presence of stimulation than did MSCs from sham-operated rats. Cumulatively, our results indicate that mechanical strain and estrogen in vitro enhance osteogenic potential and activation of β-catenin in MSCs from both sham-operated and OVX rats. Estrogen augments strain-induced osteogenic potential and activity of β-catenin in MSCs.

Anti-tumour necrosis factor therapy enhances mucosal healing through down-regulation of interleukin-21 expression and T helper type 17 cell infiltration in Crohn's disease

Anti-tumour necrosis factor (TNF) monoclonal antibody (mAb) (infliximab, IFX) has been shown to be highly effective in the management of Crohn's disease (CD). Herein we investigated the potential role of IFX in inducing clinical remission and regulating interleukin (IL)-21 expression and T helper type 17 (Th17) cell infiltration in the intestinal mucosa of CD patients. Twenty-six CD patients were treated with IFX at weeks 0, 2 and 6. Clinical response, mucosal healing, serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were evaluated at week 10 after IFX administration. Expression of IL-21, IL-17A and retinoic acid-related orphan receptor C (RORC) in intestinal mucosa were analysed by quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry. Peripheral blood and lamina propria CD4(+) T cells were stimulated with anti-CD3 and anti-CD28 mAbs in the presence of IFX. Cytokine profiles and RORC were determined with enzyme-linked immunosorbent assay (ELISA) and real-time PCR. IL-21 and Th17 cells were found to be expressed highly in inflamed mucosa of active CD patients compared with healthy controls. Ten weeks after IFX infusion, CD activity index, ESR, CRP and intestinal mucosal healing were improved markedly in CD patients, and IL-21 expression and Th17 cell infiltration were decreased significantly compared with those before IFX therapy. In-vitro study demonstrated that IFX treatment could suppress IL-21, IL-17A and RORC expression in cultured CD biopsies. Moreover, IFX was also observed to down-regulate markedly IL-17A, IL-21 and RORC expression by CD CD4(+) T cells. IFX is highly effective in inducing clinical remission and promoting intestinal mucosal healing in CD patients through down-regulation of IL-21 expression and Th17 cell infiltration in intestinal mucosa.

Exome sequencing-driven discovery of coding polymorphisms associated with common metabolic phenotypes

AIMS/HYPOTHESIS

Human complex metabolic traits are in part regulated by genetic determinants. Here we applied exome sequencing to identify novel associations of coding polymorphisms at minor allele frequencies (MAFs) >1% with common metabolic phenotypes.

METHODS

The study comprised three stages. We performed medium-depth (8×) whole exome sequencing in 1,000 cases with type 2 diabetes, BMI >27.5 kg/m(2) and hypertension and in 1,000 controls (stage 1). We selected 16,192 polymorphisms nominally associated (p < 0.05) with case-control status, from four selected annotation categories or from loci reported to associate with metabolic traits. These variants were genotyped in 15,989 Danes to search for association with 12 metabolic phenotypes (stage 2). In stage 3, polymorphisms showing potential associations were genotyped in a further 63,896 Europeans.

RESULTS

Exome sequencing identified 70,182 polymorphisms with MAF >1%. In stage 2 we identified 51 potential associations with one or more of eight metabolic phenotypes covered by 45 unique polymorphisms. In meta-analyses of stage 2 and stage 3 results, we demonstrated robust associations for coding polymorphisms in CD300LG (fasting HDL-cholesterol: MAF 3.5%, p = 8.5 × 10(-14)), COBLL1 (type 2 diabetes: MAF 12.5%, OR 0.88, p = 1.2 × 10(-11)) and MACF1 (type 2 diabetes: MAF 23.4%, OR 1.10, p = 8.2 × 10(-10)).

CONCLUSIONS/INTERPRETATION

We applied exome sequencing as a basis for finding genetic determinants of metabolic traits and show the existence of low-frequency and common coding polymorphisms with impact on common metabolic traits. Based on our study, coding polymorphisms with MAF above 1% do not seem to have particularly high effect sizes on the measured metabolic traits.

Altered white matter integrity in adolescents with prelingual deafness: a high-resolution tract-based spatial statistics imaging study

BACKGROUND AND PURPOSE

Prelingual deafness is a hearing loss that occurs before language is acquired and may result in brain structural alterations. We studied microstructural WM alterations in prelingually deaf adolescents by using DTI. We hypothesized that any morphologic alterations are mainly located in the auditory association areas. Furthermore, considering that the developing brain is both more vulnerable to deprivation and more plastic than the adult brain, we speculated that the affected areas should be larger than those previously reported in adult deafness.

MATERIALS AND METHODS

Diffusion tensor images were obtained from 16 prelingually deaf adolescents (age range, 10-18 years) and 16 healthy control adolescents matched for age and sex. Both groups were compared in fractional anisotropy and radial diffusivity by tract-based spatial statistics. In addition, we examined the correlation between the structural data (FA, RD) differences and the duration of sign language use and hearing aid experience.

RESULTS

Prelingually deaf adolescents had significantly lower FA and increased RD in the bilateral superior temporal gyri, Heschl gyrus, planum polare, and the splenium of the corpus callosum. Only RD values in the right superior temporal gyrus correlated significantly and negatively (r = -0.518; P = .040) with duration of sign language use. These alterations were larger than those previously reported in adult deafness.

CONCLUSIONS

As expected, we found severe morphologic changes of decreased FA and increased RD in multiple auditory association areas and in the corpus callosum. These changes are signs of development impairments in prelingually deaf adolescents, possibly reflecting axonal loss or lack of myelination.

Increased expression of CD24 is associated with tumor progression and prognosis in patients suffering osteosarcoma

OBJECTIVE

As a small heavily glycosylated mucin-like glycosyl-phosphatidylinositol-anchored cell surface protein, CD24 plays an important role in carcinogenesis of various human malignancies. However, its involvement in osteosarcoma is still unclear. The aim of this study was to investigate the expression pattern and the clinical significance of CD24 in human osteosarcoma.

METHODS

CD24 mRNA and protein expression levels were, respectively, detected by RT-PCR and Western blot assays using 30 pairs of osteosarcoma and noncancerous bone tissues. Then, immunohistochemistry was performed to analyze the association of CD24 expression in 166 osteosarcoma tissues with clinicopathological factors or survival of patients.

RESULTS

CD24 expression at mRNA and protein levels were both significantly higher in osteosarcoma tissues than those in corresponding noncancerous bone tissues (both P < 0.001). In addition, CD24 protein was positively expressed in 129 of 166 (77.7 %) osteosarcoma specimens with a cytoplasmic and membraneous staining, and also increased in the osteosarcoma specimens with advanced clinical stage (P = 0.01) and positive distant metastasis (P = 0.005). The univariate and multivariate analyses showed that osteosarcoma patients with high CD24 expression had poorer overall and disease-free survival, and high CD24 expression was an independent prognostic factor for both overall and disease-free survival.

CONCLUSION

The aforementioned findings offer convincing evidence for the first time that the increased expression of CD24 is correlated with tumor aggressiveness and tumor metastasis of osteosarcoma, and this molecule is an independent prognostic marker for osteosarcoma patients.

Microbial community structure in the rhizosphere of Sophora viciifolia grown at a lead and zinc mine of northwest China

Understanding the effects of heavy metal contamination on microbial activity is important for developing strategies to reclaim sites disturbed by industrial activities. In this study, we investigated arbuscular mycorrhizal (AM) fungi and bacteria associated with Sophora viciifolia growing at a lead and zinc mine in Qinling Mountain, China. Specifically, we measured the extent of AM fungal root colonization, examined microbial community structure by PCR-denaturing gradient gel electrophoresis (PCR-DGGE), and identified the dominant microorganisms. We also measured the amount of glomalin-related soil protein (GRSP) and the association of GRSP with heavy metal ions. We found that AM root colonization decreased, but total GRSP increased with the increase of the lead concentration in soil. The Shannon-Wiener Index (H') of the AM fungal community showed a significant negative correlation with the available lead concentration (r=0.92, P=0.009). Bacterial community H' was also negatively correlated with the total and available lead concentrations in the soil (r=0.97, P=0.007 and r=0.92, P=0.025 for total and available lead, respectively). Both, AM fungal and bacterial community structures differed significantly between sites along the pollution gradient. The specific distributions of the two kinds of organisms indicated their differing tolerances to heavy metal. The dominant AM fungi were identified as Glomeraceae, whereas the dominant bacteria belonged to Proteobacteria. The amount of lead bound to GRSP varied from 3.3 to 172.5 mg kg(-1), which positively correlated with total and available soil lead concentration (r=0.99, P<0.000 and r=0.93, P=0.020 for total soil lead and available soil lead concentration, respectively), thus reducing the bioavailability of heavy metal ions.

Role of antisite disorder on preamorphization swelling in titanate pyrochlores

Ion irradiation experiments and atomistic simulations were used to demonstrate that irradiation-induced lattice swelling in a complex oxide, Lu2Ti2O7, is due initially to the formation of cation antisite defects. X-ray diffraction revealed that cation antisite formation correlates directly with lattice swelling and indicates that the volume per antisite pair is approximately 12  Å3. First principles calculations revealed that lattice swelling is best explained by cation antisite defects. Temperature accelerated dynamics simulations indicate that cation Frenkel defects are metastable and decay to form antisite defects.