Embryonic Intra-Aortic Clusters Undergo Myeloid Differentiation Mediated by Mesonephros-Derived CSF1 in Mouse.

The aorta-gonad-mesonephros (AGM) region contains intra-aortic clusters (IACs) thought to have acquired hematopoietic stem cell (HSC) potential in vertebrate embryos. To assess extrinsic regulation of IACs in the AGM region, we employed mouse embryos harboring a Sall1-GFP reporter gene, which allows identification of mesonephros cells based on GFP expression. Analysis of AGM region tissue sections confirmed mesonephros GFP expression. Mesonephric cells sorted at E10.5 expressed mRNA encoding Csf1, a hematopoietic cytokine, and corresponding protein, based on real-time PCR and immunocytochemistry, respectively. Further analysis indicated that some IACs express the CSF1 receptor, CSF1R. Expression of Cebpa and Irf8 mRNAs was higher in CSF1R-positive IACs, whereas that of Cebpε and Gfi1 mRNAs was lower relative to CSF1R-negative IACs, suggesting that CSF1/CSF1R signaling functions in IAC myeloid differentiation by modulating expression of these transcription factors. Colony formation assays using CSF1R-positive IACs revealed increased numbers of myeloid colonies in the presence of CSF1. Analysis using an intra-cellular signaling array indicated the greatest fold increase of Cleaved Caspase-3 in AGM cells in the presence of CSF1. Immunohistochemistry revealed that Cleaved Caspase-3 is primarily expressed in IACs in the AGM region, and incubation of IACs with CSF1 up-regulated Cleaved Caspase-3. Overall, our findings suggest that CSF1 secreted from mesonephros accelerates IAC myeloid differentiation in the AGM region, possibly via Caspase-3 cleavage.

Up-regulation of endothelial nitric oxide synthase (eNOS), silent mating type information regulation 2 homologue 1 (SIRT1) and autophagy-related genes by repeated treatments with resveratrol in human umbilical vein endothelial cells.

Resveratrol, a polyphenolic phytoalexin found in red wine and various plants, has been reported to up-regulate the expression of endothelial NO synthase (eNOS) in human umbilical vein endothelial cells (HUVEC). However, this effect was neither long term in nature nor physiologically relevant at the concentration of resveratrol studied. In the present study, we investigated the effects of repeated treatments with a lower concentration of resveratrol on the expression of genes in HUVEC. The expression levels of eNOS and silent mating type information regulation 2 homologue 1 (SIRT1) were up-regulated in HUVEC by repeated treatments with 1 µM-resveratrol for 6 d, but not with fenofibrate. Moreover, resveratrol treatment increased the expression of autophagy-regulated genes such as γ-aminobutyric acid A receptor-associated protein (GABARAP), microtubule-associated protein 1 light chain 3B (LC3B) and autophagy-related protein 3 (ATG3), the radical scavenger activity-related metallothionein-1X (MT1X) gene and the anti-inflammatory activity-related annexin A2 (ANXA) gene. In addition, resveratrol treatment down-regulated the expression of the cell-cycle checkpoint control RAD9 homologue B (RAD9B) gene. These results indicate the beneficial effects of resveratrol on the cardiovascular system.

Secretion of miraculin through the function of a signal peptide conserved in the Kunitz-type soybean trypsin inhibitor family.

Miraculin, a glycoprotein that modifies sour tastes into sweet ones, belongs to the Kunitz-type soybean trypsin inhibitor (STI) family. To clarify the functional relation of miraculin with Kunitz-type STIs, we investigated its subcellular localization and trypsin inhibitory activity. In transgenic Arabidopsis thaliana, miraculin, fused to yellow fluorescent protein, localized to and outside the plasma membrane depending on the putative secretion signal peptide. When transgenic seedlings were cultured in liquid medium, miraculin was present in the supernatant only after cellulase treatment. No trypsin inhibitory activity was detected in native or recombinant miraculin. In conclusion, miraculin is secreted outside the plasma membrane through the function of a signal peptide, conserved in Kunitz-type STIs, whereas its trypsin inhibitory activity may be lost during its evolution.