Adaptable haemodynamic endothelial cells for organogenesis and tumorigenesis

Endothelial cells adopt tissue-specific characteristics to instruct organ development and regeneration1,2. This adaptability is lost in cultured adult endothelial cells, which do not vascularize tissues in an organotypic manner. Here, we show that transient reactivation of the embryonic-restricted ETS variant transcription factor 2 (ETV2)3 in mature human endothelial cells cultured in a serum-free three-dimensional matrix composed of a mixture of laminin, entactin and type-IV collagen (LEC matrix) ‘resets’ these endothelial cells to adaptable, vasculogenic cells, which form perfusable and plastic vascular plexi. Through chromatin remodelling, ETV2 induces tubulogenic pathways, including the activation of RAP1, which promotes the formation of durable lumens4,5. In three-dimensional matrices—which do not have the constraints of bioprinted scaffolds—the ‘reset’ vascular endothelial cells (R-VECs) self-assemble into stable, multilayered and branching vascular networks within scalable microfluidic chambers, which are capable of transporting human blood. In vivo, R-VECs implanted subcutaneously in mice self-organize into durable pericyte-coated vessels that functionally anastomose to the host circulation and exhibit long-lasting patterning, with no evidence of malformations or angiomas. R-VECs directly interact with cells within three-dimensional co-cultured organoids, removing the need for the restrictive synthetic semipermeable membranes that are required for organ-on-chip systems, therefore providing a physiological platform for vascularization, which we call ‘Organ-On-VascularNet’. R-VECs enable perfusion of glucose-responsive insulin-secreting human pancreatic islets, vascularize decellularized rat intestines and arborize healthy or cancerous human colon organoids. Using single-cell RNA sequencing and epigenetic profiling, we demonstrate that R-VECs establish an adaptive vascular niche that differentially adjusts and conforms to organoids and tumoroids in a tissue-specific manner. Our Organ-On-VascularNet model will permit metabolic, immunological and physiochemical studies and screens to decipher the crosstalk between organotypic endothelial cells and parenchymal cells for identification of determinants of endothelial cell heterogeneity, and could lead to advances in therapeutic organ repair and tumour targeting

The new catalytic property of supported rhenium oxides for selective oxidation of methanol to methylal

A new catalytic property of supported rhenium oxides has been found for selective methanol oxidation to methylal; high performances for the selective catalytic oxidation are observed with V2O5-, ZrO2-, Fe2O3- and TiO2-supported Re-oxide catalysts, which are characterized by pulse experiments, XRD and XPS

Performance and characterization of a new crystalline SbRe2O6 catalyst for selective oxidation of methanol to methylal

Three well-defined compounds, SbRe2O6, Sb4Re2O13, and SbOReO4 . 2H(2)O, and several supported Re catalysts were employed as catalysts for the selective oxidation of methanol to methylal (3CH(3)OH + 1/2O(2) --> CH2(OCH3)(2) + 2H(2)O). High selectivity of 92.5% to methylal was obtained on the new crystalline catalyst SbRe2O6 at 573 K, while no methylal formation or negligible activity was observed with the other catalysts. No structural change in the bulk and surface of the SbRe2O6 catalyst occurred after the methanol oxidation below 600 K as characterized by XRD, Raman, XPS, and SEM. The reaction rate increased with increasing methanol partial pressure, while the selectivity to methylal was independent of methanol partial pressure as well as O-2 partial pressure (<10 mol%). There existed two types of active lattice oxygen species in TPD experiments on SbRe2O6, both being responsible for the methylal formation. The high performance of SbRe2O6 for the selective synthesis of methylal from methanol may be ascribed to the Re-oxide species stabilized by the specific connection with Sb oxides at the crystal surface. (C) 2000 Academic Press

Selective synthesis of methylal from methanol on a new crystalline SbRe2O6 catalyst

A novel SbRe2O6 catalyst was active for the selective methanol oxidation to methylal (CH2(OCH3)(2)). Other known Sb-Re oxides, Sb4Re2O13 and SbOReO4. 2H(2)O produced almost no methylal. The bulk and surface of the SbRe2O6 catalyst was characterized by XRD, Raman, XPS and SEM. The high performance of SbRe2O6 may be attributed to the Re-oxide octahedra connecting with Sb-O chains