Loss of endothelial-ARNT in adult mice contributes to dampened circulating proangiogenic cells and delayed wound healing.

The recruitment and homing of circulating bone marrow-derived cells include endothelial progenitor cells (EPCs) that are critical to neovascularization and tissue regeneration of various vascular pathologies. We report here that conditional inactivation of hypoxia-inducible factor's (HIF) transcriptional activity in the endothelium of adult mice (Arnt(ΔiEC) mice) results in a disturbance of infiltrating cells, a hallmark of neoangiogenesis, during the early phases of wound healing. Cutaneous biopsy punches show distinct migration of CD31(+) cells into wounds of control mice by 36 hours.

Hypoxia influences the vascular expansion and differentiation of embryonic stem cell cultures through the temporal expression of vascular endothelial growth factor receptors in an ARNT-dependent manner.

Adaptive responses to low oxygen (O(2)) tension (hypoxia) are mediated by the heterodimeric transcription factor hypoxia inducible factor (HIF). When stabilized by hypoxia, bHLH-PAS alpha- and beta- (HIF-1beta or ARNT) HIF complex regulate the expression of multiple genes, including vascular endothelial growth factor (VEGF). To investigate the mechanism(s) through which hypoxia contributes to blood vessel development, we used embryonic stem cell (ESC) differentiation cultures that develop into embryoid bodies (EBs) mimicking early embryonic development.

Effects of green tea polyphenols on murine transplant-reactive T cell immunity.

Green tea polyphenols (GrTP), the active ingredient of green tea, may have immunosuppressive properties, but whether and how GrTP affect transplant-reactive T cells is unknown. To address this, we tested the effects of GrTP on in vitro and in vivo transplant-reactive T cell immunity. GrTP inhibited IFNgamma secretion by cultured monoclonal T cells and by alloreactive T cells in mixed lymphocyte reactions.

Functional characterization of NBC4: a new electrogenic sodium-bicarbonate cotransporter.

Sodium-bicarbonate cotransporters are homologous membrane proteins mediating the electrogenic or electroneutral transport of sodium and bicarbonate. Of the functionally characterized sodium-bicarbonate cotransporters (NBC), NBC1 proteins are known to be electrogenic. Here we report the cloning and functional characterization of NBC4c, a new splice variant of the NBC4 gene.