Overall, this strongly suggests that a paracrine loop could be involved in B. henselae VEGF action. However, up to now, the majority of these studies have been carried out on macrovascular ECs. Interestingly, using our species- and organ-specific ECs model, we showed that B. henselae increased VEGF production by Human Skin Microvascular ECs but not by iHUVEC or feline macro- or micro-vascular ECs. These results, which might explain the decreased pathogenic potential of B. henselae infection for cat as compared to human, strongly suggests the involvement of an autocrine secretion of VEGF by skin ECs. This finding points out that the mechanism of B. henselae-mediated angiogenesis induction implies autocrine VEGF production and stimulation of the infected endothelium. In parallel to VEGF production, the phosphorylation of VEGFR-2 was observed in ECs upon infection, mostly by homologous strains. This phenomenon is of high interest in the context of epidemiological human infection. As B. henselae isolates infecting a human have always a feline origin, it is tempting to speculate that an adaptive switch is taking place upon cat scratch in humans. Altogether, our results raise the hypothesis of hostdependent signaling in ECs upon bacterial infection as VEGFR-2 activation is more prominent in human ECs exposed to homologous strains. The same holds true for feline ECs. Because bacillary angiomatosis is not detected in cats infected by homologous strains, alternate mechanisms are likely taking place, Our results support the fact that VEGF signaling might be increased in human ECs through an autocrine production, which does not occur in feline ECs. Paracrine VEGF activation cannot be excluded; therefore, it will be interesting to further Vismodegib Hedgehog inhibitor investigate whether VEGF can be released in the perivascular microenvironment by other cells, such as macrophages and polymorphonuclear cells. Our results on VEGF and VEGFR-2 are in BI-D1870 apparent contradiction with those obtained by Scheidegger et al. However, the concentration ranges and source of VEGF were far for being comparable. Our study highlights the ECs organo- and species- specificity in their interactions with B. henselae. Indeed, our model further demonstrates the difference of reactivity displayed by human vs feline ECs on the one hand and by the macro- vs the microvasculature on the other hand. Additionally, local physiological microenvironment is most likely to play an important role. In this context, our cellular systems will allow studying the process of specific ECs infection by B. henselae. They will offer new possibilities to investigate bacterial and cellular factors which determine human vs cat reactivity, as well as the mechanisms involved in anti-apoptotic and/or pro-angiogenic effects, ultimately resulting to bacillary angiomatosis and peliosis only in humans. In conclusion, according to the validated hypothesis stating the organospecificity of the endothelium, our work extends this concept to the species-specific endothelial cell phenotypes.

kinase inhibitors tumors from both models also contained a high percentage of proliferating cells characterized by both Ki67 staining and a large number of mitotic cells and exhibited regions with substantial numbers of necrotic and apoptotic cells. The similarities between the mouse and human tumors are also highlighted by the gene expression microarray studies which found a 68.1% Pearson correlation in quartiled and grade adjusted gene expression. However, there are also several differences including: the presence of large nondividing ganglion-like cells in all the mouse tumors and larger, somewhat ganglion-like cells in only some of the human OSI-774 xenografts. In addition, the majority of the mouse tumors fail to macrometastasize beyond the local area. Eighteen genes were also differentially expressed in the human and mouse tumors. These differences may contribute to their tumorigenicity and/or metastatic abilities. For example the mouse tumors expressed higher levels of BRCA2, a known tumor suppressor gene in breast and ovarian cancer and involved in maintenance of genome stability, specifically the homologous recombination pathway for doublestrand DNA repair. We do not yet know if any of these 18 genes account for the differences in disease progression between the human and mouse neuroblastomas but our ultrasound guided engraftment procedure is suited for testing these hypotheses. Our ultrasound studies showed that 81% of initial tumors in the TH-MYCN mice are found surrounding or in the vicinity of the aorta in the paravertebral ganglia. The percentage of tumors in humans originating from the paraspinal ganglia is,60%. We speculate that this site in the mouse provides factors from the blood system and from the adjacent adrenal that can enhance tumor growth and progression. Surprisingly, none of the mouse NB tumors originated in the adrenal medulla itself as confirmed by ultrasonography, histology and electron microscopy. These results are in agreement with recent works observing initial tumor formation in the TH-MYCN mouse in early postnatal sympathetic ganglia and not in the adrenal. However, in a few cases we observed that the mouse tumors invaded the adrenal at later stages of tumor progression. This is in contrast to the human disease where approximately 40% of the patient tumors originate in the adrenal medulla. Recording the in vivo regression of a small group of TH-MYCN tumors by ultrasound and MRI opens the possibility of using this model to study this process and suggests these tumors may exhibit similarities to human stage 4S tumor which also spontaneously regress. Understanding the regression process in vivo could help identify the biological pathways that will facilitate tumor growth arrest and drive the tumor to complete regression.

To investigate whether this mutant could be affected during D. dadantii infection, we analysed the disease symptoms produced on the bos1 mutant after low bacterial inoculum deposition on wounded leaves. On Col-0 wild type plants, typical soft rot usually developed spreading to the whole infected leaf, but in some cases, a DAPT Gamma-secretase inhibitor chlorosis appeared around the maceration zone forming a yellow ring. In the bos1 mutant such a chlorosis developed in almost all cases, expanded to the whole infected leaf and spread systemically to the whole plant leading to a complete death of bos1 mutants. This chlorosis always turned into necrosis. The systemic necrosis of infected plants was not observed either after Navitoclax non-pathogenic enterobacterium inoculation or after B. cinerea mycelium application. This indicated that a specific factor associated to D. dadantii might trigger this necrotic response. The role that this necrotic response to D. dadantii inoculation might play in disease development has been analyzed by quantifying maceration symptoms, necrosis occurrence and bacterial growth in bos1 and Col-0 plants. After inoculation with a 5 ml drop of a 104 cfu/mL bacterial suspension, soft rot symptoms developed during the first 2 dpi in both genotypes but significantly faster in bos1 leaves than in WT. Necrosis around the maceration zone developed from the second dpi in both genotypes but less frequently in Col-0 than in bos1. In wild type plants however, this necrosis always stayed restricted to the few plant cells surrounding the rotted tissue. In contrast, in bos1 plants, the necrosis expanded to the whole infected leaves from 3 dpi onwards and affected rapidly the whole plant in most cases. This necrosis symptom was concomitant with an arrest of soft rot expansion and a drying of the maceration zone so that from the third dpi onwards, maceration symptoms did not evolve on the bos1 mutant and the soft rot did not expand to more than one half of the infected leaves except in a few cases. In contrast, maceration continued to progress in WT leaves leading to the complete rotting of more than 40% of infected leaves at 6 dpi. To evaluate the consequence of necrosis on the infecting bacterial population, bacterial growth was monitored in planta in both genotypes. One day post inoculation, a 100-fold multiplication was observed in both genotypes. Two dpi, about 10-fold more bacteria were found in bos1 infected leaves compared to wild type ones. On the contrary, a further increase in bacterial population was observed 3 dpi in wild type infected leaves while the number of bacteria declined in bos1 leaves, correlating with the halt of maceration expansion and the appearance of the necrosis. In all chlorotic or necrotic systemic leaves tested, we never detected the presence of bacteria except for the rare leaves exhibiting maceration symptoms.

In addition, remodeling and hypertrophy of VSMCs may be involved in the progression of essential hypertension. The mechanisms of VSMC phenotypic modulation remain elusive despite intense investigation. However, several transcription factors, including serum response factor, myocardin, myocardin related transcription factors and members of the Kru�� ppel-like zinc finger family have been suggested to act as molecular switches regulating VSMC differentiation. During the last decade, microRNAs, which are short noncoding RNAs have been suggested to regulate mRNA expression NSC-718781 levels and translational efficiency and play a fundamental role in a number of human disease states, including vascular disease. Specific miRNAs have been shown to regulate VSMC phenotypic modulation and/or control VSMC fate and differentiation. miR-21 and miR-221 were initially found to play a role in SMC proliferation and differentiation and more recently, miR-145 was shown to be specifically expressed in SMCs and play an important role in SMC differentiation. Studies on miR-143/145 KO mice later revealed that these miRNAs are important but not essential for VSMC development in vivo. miRNAs are produced from immature pre-miRNAs, which are processed by the two RNase III endonucleases, Drosha and Dicer, and are then incorporated into the RNA-induced silencing complex . Depending on the complementarity of the miRNA with the 3��-untranslated region of the target mRNA, the RISC complex will mediate either translational repression/ activation or degradation of the target mRNA. Since Dicer is required for processing of almost all mature miRNAs, mutation or disruption of Dicer has been widely used as an approach to investigate the biological significance of miRNAs in Gefitinib various cell types including cardiomyocytes, endothelial cells, fibroblasts and immune cells 24�C26]. Our group recently reported that conditional loss of Dicer in VSMCs during embryonic development results in embryonic lethality associated with extensive internal hemorrhage as well as dilated and thin walled blood vessels caused by a reduction in cellular proliferation. In addition, arteries from SM-Dicer KO embryos exhibited impaired contractility due to a loss of contractile differentiation of VSMCs. In isolated Dicer KO VSMCs, loss of contractile differentiation was rescued by miR-145 mimic, possibly via increased actin polymerization. Although miR-145 can rescue several defects in cultured SMCs, the absence of a lethal phenotype of miR-145 KO mice suggests that other miRNAs or combinations of miRNAs are important for SMC development and function. Since deletion of Dicer during prenatal development is embryonic lethal it is not possible to investigate the importance of miRNAs in VSMC function and blood pressure regulation in adult mice using this model.

We used different FDR cutoffs for breast and stroma to obtain lists of differentially expressed genes of comparable size. The fact that we had to use a higher FDR in the case of prostate LEE011 1211441-98-3 cancer confirms that the overall stromal response is weaker than in breast cancer. Comparison to datasets from studies on human breast and pancreatic and murine prostate cancer revealed a high degree of similarity between upregulated genes in our breast cancer patient stroma and upregulated genes in the Ma et al. and Bauer et al. study of breast tumors as well as in the Binkley et al. study of the stromal response to pancreatic cancer . Significant similarity was also found with the mouse stromal response to neuroendocrine prostate cancer growth. The prostate cancer stromal signature was also significantly related to these four datasets, albeit to a lesser degree than the breast cancer signature. As expected, our breast cancer stromal signature was more closely related to the two breast signatures than our prostate cancer stromal signature. In addition, both our breast and prostate cancer stromal signatures displayed similarity with pancreatic cancer and mouse neuroendocrine prostate cancer stroma signatures. Closer examination of the signatures, however, revealed that the similarity resided primarily among genes implicated in tissue remodeling. Periostin, found to be upregulated in both breast and prostate cancer stroma, was selected for immunohistochemical validation in a panel of human tumors known to be associated with a prominent stromal reaction. Representative images shown in Figure 2 confirm the increase of POSTN expression in the stromal compartment of breast and prostate tumor samples, compared to their normal counterparts. Intense POSTN expression was also observed in the stroma of ovarian carcinoma, as well as in lung and colon carcinoma where it was concentrated at the interface between the tumor epithelial cells and the stromal compartment that presented a robust inflammatory reaction. It is noteworthy that POSTN was not expressed in the tumor cells of the samples analyzed. Kaplan-Meier survival analysis indicated that the overall lists of breast and prostate cancer stromal genes had high prognostic value in human breast and prostate cancer datasets, respectively, but did not allow the identification of genes whose expression level is most strongly associated with patient survival. To address this issue, univariate Cox analysis was GDC-0199 in vivo performed to correlate the level of gene expression with patient survival. For each gene, a z value was obtained, indicating the strength of the correlation between the level of gene expression and patient survival. Positive z values indicated that the expression level of a gene was associated with poor prognosis,