Rapid neutrophil adhesion to activated endothelium mediated by GMP-140.

Granule membrane protein-140 (GMP-140), a membrane glycoprotein of platelet and endothelial cell secretory granules, is rapidly redistributed to the plasma membrane during cellular activation and degranulation. Also known as PADGEM protein, GMP-140 is structurally related to two molecules involved in leukocyte adhesion to vascular endothelium: ELAM-1, a cytokine-inducible endothelial cell receptor for neutrophils, and the MEL-14 lymphocyte homing receptor. These three proteins define a new gene family, termed selectins, each of which contains an N-terminal lectin domain, followed by an epidermal growth factor-like module, a variable number of repeating units related to those in complement-binding proteins, a transmembrane domain, and a short cytoplasmic tail. Here we demonstrate that GMP-140 can mediate leukocyte adhesion, thus establishing a functional similarity with the other selectins. Human neutrophils and promyelocytic HL-60 cells bind specifically to COS cells transfected with GMP-140 complementary DNA and to microtitre wells coated with purified GMP-140. Cell binding does not require active neutrophil metabolism but is dependent on extracellular Ca2+. Within minutes after stimulation with phorbol esters or histamine, human endothelial cells become adhesive for neutrophils; this interaction is inhibited by antibodies to GMP-140. Thus, GMP-140 expressed by activated endothelium might promote rapid neutrophil targeting to sites of acute inflammation.     

Cryopyrin activates the inflammasome in response to toxins and ATP

A crucial part of the innate immune response is the assembly of the inflammasome, a cytosolic complex of proteins that activates caspase-1 to process the proinflammatory cytokines interleukin (IL)-1beta and IL-18. The adaptor protein ASC is essential for inflammasome function, binding directly to caspase-1 (refs 3, 4), but the triggers of this interaction are less clear. ASC also interacts with the adaptor cryopyrin (also known as NALP3 or CIAS1). Activating mutations in cryopyrin are associated with familial cold autoinflammatory syndrome, Muckle-Wells syndrome and neonatal onset multisystem inflammatory disease, diseases that are characterized by excessive production of IL-1beta. Here we show that cryopyrin-deficient macrophages cannot activate caspase-1 in response to Toll-like receptor agonists plus ATP, the latter activating the P2X7 receptor to decrease intracellular K+ levels. The release of IL-1beta in response to nigericin, a potassium ionophore, and maitotoxin, a potent marine toxin, was also found to be dependent on cryopyrin. In contrast to Asc-/- macrophages, cells deficient in the gene encoding cryopyrin (Cias1-/-) activated caspase-1 and secreted normal levels of IL-1beta and IL-18 when infected with Gram-negative Salmonella typhimurium or Francisella tularensis. Macrophages exposed to Gram-positive Staphylococcus aureus or Listeria monocytogenes, however, required both ASC and cryopyrin to activate caspase-1 and secrete IL-1beta. Therefore, cryopyrin is essential for inflammasome activation in response to signalling pathways triggered specifically by ATP, nigericin, maitotoxin, S. aureus or L. monocytogenes.     

DNA sequence and comparative analysis of chimpanzee chromosome 22

Human-chimpanzee comparative genome research is essential for narrowing down genetic changes involved in the acquisition of unique human features, such as highly developed cognitive functions, bipedalism or the use of complex language. Here, we report the high-quality DNA sequence of 33.3 megabases of chimpanzee chromosome 22. By comparing the whole sequence with the human counterpart, chromosome 21, we found that 1.44% of the chromosome consists of single-base substitutions in addition to nearly 68,000 insertions or deletions. These differences are sufficient to generate changes in most of the proteins. Indeed, 83% of the 231 coding sequences, including functionally important genes, show differences at the amino acid sequence level. Furthermore, we demonstrate different expansion of particular subfamilies of retrotransposons between the lineages, suggesting different impacts of retrotranspositions on human and chimpanzee evolution. The genomic changes after speciation and their biological consequences seem more complex than originally hypothesized.     

Normalization of current kinetics by interaction between the alpha 1 and beta subunits of the skeletal muscle dihydropyridine-sensitive Ca2+ channel.

Purification of skeletal muscle dihydropyridine binding sites has enabled protein complexes to be isolated from which Ca2+ currents have been reconstituted. Complementary DNAs encoding the five subunits of the dihydropyridine receptor, alpha 1, beta, gamma, alpha 2 and delta, have been cloned and it is now recognized that alpha 2 and delta are derived from a common precursor. The alpha 1 subunit can itself produce Ca2+ currents, as was demonstrated using mouse L cells lacking alpha 2 delta, beta and gamma (our unpublished results). In L cells, stable expression of skeletal muscle alpha 1 alone was sufficient to generate voltage-sensitive, high-threshold L-type Ca2+ channel currents which were dihydropyridine-sensitive and blocked by Cd2+, but the activation kinetics were about 100 times slower than expected for skeletal muscle Ca2+ channel currents. This could have been due to the cell type in which alpha 1 was being expressed or to the lack of a regulatory component particularly one of the subunits that copurifies with alpha 1. We show here that coexpression of skeletal muscle beta with skeletal muscle alpha 1 generates cell lines expressing Ca2+ channel currents with normal activation kinetics as evidence for the participation of the dihydropyridine-receptor beta subunits in the generation of skeletal muscle Ca2+ channel currents.     

Epigenetic mechanisms in mammals

DNA and histone methylation are linked and subjected to mitotic inheritance in mammals. Yet how methylation is propagated and maintained between successive cell divisions is not fully understood. A series of enzyme families that can add methylation marks to cytosine nucleobases, and lysine and arginine amino acid residues has been discovered. Apart from methyltransferases, there are also histone modification enzymes and accessory proteins, which can facilitate and/or target epigenetic marks. Several lysine and arginine demethylases have been discovered recently, and the presence of an active DNA demethylase is speculated in mammalian cells. A mammalian methyl DNA binding protein MBD2 and de novo DNA methyltransferase DNMT3A and DNMT3B are shown experimentally to possess DNA demethylase activity. Thus, complex mammalian epigenetic mechanisms appear to be dynamic yet reversible along with a well-choreographed set of events that take place during mammalian development.     

Wnt-dependent de novo hair follicle regeneration in adult mouse skin after wounding

The mammalian hair follicle is a complex 'mini-organ' thought to form only during development; loss of an adult follicle is considered permanent. However, the possibility that hair follicles develop de novo following wounding was raised in studies on rabbits, mice and even humans fifty years ago. Subsequently, these observations were generally discounted because definitive evidence for follicular neogenesis was not presented. Here we show that, after wounding, hair follicles form de novo in genetically normal adult mice. The regenerated hair follicles establish a stem cell population, express known molecular markers of follicle differentiation, produce a hair shaft and progress through all stages of the hair follicle cycle. Lineage analysis demonstrated that the nascent follicles arise from epithelial cells outside of the hair follicle stem cell niche, suggesting that epidermal cells in the wound assume a hair follicle stem cell phenotype. Inhibition of Wnt signalling after re-epithelialization completely abrogates this wounding-induced folliculogenesis, whereas overexpression of Wnt ligand in the epidermis increases the number of regenerated hair follicles. These remarkable regenerative capabilities of the adult support the notion that wounding induces an embryonic phenotype in skin, and that this provides a window for manipulation of hair follicle neogenesis by Wnt proteins. These findings suggest treatments for wounds, hair loss and other degenerative skin disorders.     

Development of a Measurement System Far-IR Using a MCT Sensor

The far-infrared radiation （Far-IR） has good effects on us, promoting the circulation of the blood and metabolic. So textile products including far-IR have been developed. But it is very difficult to measure the amount of far-IR in the textile quicHy and correctly. Newly developed Mercury Cadmium Telluride （MCT） sensor system could solve this problem.     

Generation of functional multipotent adult stem cells from GPR125+ germline progenitors

Adult mammalian testis is a source of pluripotent stem cells. However, the lack of specific surface markers has hampered identification and tracking of the unrecognized subset of germ cells that gives rise to multipotent cells. Although embryonic-like cells can be derived from adult testis cultures after only several weeks in vitro, it is not known whether adult self-renewing spermatogonia in long-term culture can generate such stem cells as well. Here, we show that highly proliferative adult spermatogonial progenitor cells (SPCs) can be efficiently obtained by cultivation on mitotically inactivated testicular feeders containing CD34+ stromal cells. SPCs exhibit testicular repopulating activity in vivo and maintain the ability in long-term culture to give rise to multipotent adult spermatogonial-derived stem cells (MASCs). Furthermore, both SPCs and MASCs express GPR125, an orphan adhesion-type G-protein-coupled receptor. In knock-in mice bearing a GPR125-beta-galactosidase (LacZ) fusion protein under control of the native Gpr125 promoter (GPR125-LacZ), expression in the testis was detected exclusively in spermatogonia and not in differentiated germ cells. Primary GPR125-LacZ SPC lines retained GPR125 expression, underwent clonal expansion, maintained the phenotype of germline stem cells, and reconstituted spermatogenesis in busulphan-treated mice. Long-term cultures of GPR125+ SPCs (GSPCs) also converted into GPR125+ MASC colonies. GPR125+ MASCs generated derivatives of the three germ layers and contributed to chimaeric embryos, with concomitant downregulation of GPR125 during differentiation into GPR125- cells. MASCs also differentiated into contractile cardiac tissue in vitro and formed functional blood vessels in vivo. Molecular bookmarking by GPR125 in the adult mouse and, ultimately, in the human testis could enrich for a population of SPCs for derivation of GPR125+ MASCs, which may be employed for genetic manipulation, tissue regeneration and revascularization of ischaemic organs.     

The Constituents of Diterpenoids from Isodon excisa

从唇形科尾叶香茶菜叶子的甲醇提取物中，分离提取了４个对映－贝壳杉烯型二萜，并利用核磁共振氢谱和碳谱，以及质谱、红外光谱和紫外光谱等方法，对以上各化合物进行了结构鉴定．化合物１在该植物的文献中未见报道．