Urotensin II and urantide exert opposite effects on the cellular components of atherosclerotic plaque in hypercholesterolemic rabbits.

Increasing levels of plasma urotensin II (UII) are positively associated with atherosclerosis. In this study we investigated the role of macrophage-secreted UII in atherosclerosis progression, and evaluated the therapeutic value of urantide, a potent competitive UII receptor antagonist, in atherosclerosis treatment. Macrophage-specific human UII-transgenic rabbits and their nontransgenic littermates were fed a high cholesterol diet for 16 weeks to induce atherosclerosis. Immunohistochemical staining of the cellular components (macrophages and smooth muscle cells) of aortic atherosclerotic lesions revealed a significant increase (52%) in the macrophage-positive area in only male transgenic rabbits compared with that in the nontransgenic littermates. However, both male and female transgenic rabbits showed a significant decrease (45% in males and 31% in females) in the smooth muscle cell-positive area compared with that of their control littermates. The effects of macrophage-secreted UII on the plaque cellular components were independent of plasma lipid level. Meanwhile the wild-type rabbits were continuously subcutaneously infused with urantide (5.4 µg· kg-1· h-1) using osmotic mini-pumps. Infusion of urantide exerted effects opposite to those caused by UII, as it significantly decreased the macrophage-positive area in male wild-type rabbits compared with that of control rabbits. In cultured human umbilical vein endothelial cells, treatment with UII dose-dependently increased the expression of the adhesion molecules VCAM-1 and ICAM-1, and this effect was partially reversed by urantide. The current study provides direct evidence that macrophage-secreted UII plays a key role in atherogenesis. Targeting UII with urantide may promote plaque stability by decreasing macrophage-derived foam cell formation, which is an indicator of unstable plaque.

Genetic analysis and gene mapping of the glabrous leaf and hull mutant glr3 in rice (Oryza sativa L.).

We obtained a glabrous leaf and hull mutant from a population of radiation mutagenesis of an indica rice cultivar R401. The mutant produced smooth leaves and hairless glumes under normal growth conditions. An F2 population was developed from a cross between a japonica cultivar Nipponbare and the glabrous leaf and hull mutant. By investigating the performance of the F2 population, we found that the mutant phenotype was controlled by a single recessive gene, temporarily designated GLR3. Bulked segregant analysis (BSA) based on the F2 mapping population revealed that GLR3 is located on chromosome 6. By analyzing 417 typical glabrous leaf F2 plants using molecular markers, GLR3 was mapped to a 0.2 cM interval between InDel markers ID27101 and ID27199, and the physical distance between the two markers is 98 kb. Thus we have mapped the gene GLR3, and our work will provide basis for future mechanistic analysis of GLR3 function.