0000000000021389
AUTHOR
Nadhir Yousfi
The impact of tumor nitric oxide production on VEGFA expression and tumor growth in a zebrafish rat glioma xenograft model.
International audience; To investigate the effect of nitric oxide on tumor development, we established a rat tumor xenograft model in zebrafish embryos. The injected tumor cells formed masses in which nitric oxide production could be detected by the use of the cell-permeant DAF-FM-DA (diaminofluorophore 4-amino-5-methylamino-2'-7'-difluorofluorescein diacetate) and DAR-4M-AM (diaminorhodamine-4M). This method revealed that nitric oxide production could be co-localized with the tumor xenograft in 46% of the embryos. In 85% of these embryos, tumors were vascularized and blood vessels were observed on day 4 post injection. Furthermore, we demonstrated by qRT-PCR that the transplanted glioma ce…
zHSF1 modulates zper2 expression in zebrafish embryos
International audience; HSF1 is a transcription factor that plays a key role in circadian resetting by temperature. We have used zebrafish embryos to decipher the roles of zHsf1, heat and light on zper2 transcription in vivo. Our results show that heat shock (HS) stimulated zper2 expression in the dark but has no cumulative effect combined with light. After light exposition, zper2 expression was 2.7 fold increased threefold in the hsf1-morphants in comparison to control embryos. Our results show that zHsf1 plays a positive role in HS-driven expression of zper2 in the dark but seems to act as an attenuator in the presence light.
The biofilm mode of life boosts the anti-inflammatory properties ofLactobacillus
Summary The predominant form of life for microorganisms in their natural habitats is the biofilm mode of growth. The adherence and colonization of probiotic bacteria are considered as essential factors for their immunoregulatory function in the host. Here, we show that Lactobacillus casei ATCC334 adheres to and colonizes the gut of zebrafish larvae. The abundance of pro-inflammatory cytokines and the recruitment of macrophages were low when inflammation was induced in probiotic-fed animals, suggesting that these bacteria have anti-inflammatory properties. We treated human macrophage-differentiated monocytic THP-1 cells with supernatants of L. casei ATCC334 grown in either biofilm or plankto…
Extracellular HSP27 mediates angiogenesis through Toll-like receptor 3.
The heat-shock protein 27 (HSP27) is up-regulated in tumor cells and released in their microenvironment. Here, we show that extracellular HSP27 has a proangiogenic effect evidenced on chick chorioallantoic membrane. To explore this effect, we test the recombinant human protein (rhHSP27) at physiopathological doses (0.1-10 μg/ml) onto human microvascular endothelial cells (HMECs) grown as monolayers or spheroids. When added onto HMECs, rhHSP27 dose-dependently accelerates cell migration (with a peak at 5 μg/ml) and favors spheroid sprouting within 12-24 h. rhHSP27 increases VEGF gene transcription and promotes secretion of VEGF-activating VEGF receptor type 2. Increased VEGF transcription is…