To define the effects of feeding and sleep regulating peptides, orexins, in immunocompetent cells, the effects of orexin-A and orexin-B on phagocytosis in mouse peritoneal macrophages were examined. Orexin-B induced an enhancement of phagocytosis in a dose-dependent manner. Orexin-A is less effective than orexin-B. Even in Ca2+-free solutions, phagocytosis was enhanced by orexin-B. The potassium channel blocker quinine inhibited the enhanced phagocytosis by orexin-B; 4-aminopyridine and tetraethylammonium suppressed phagocytosis less effectively. These results suggest that orexins can enhance the phagocytosis of macrophages mediated by potassium channels.
TE671/RD is a cell line obtained from the rhabdomyosarcoma cells. In the present study, we examined [Ca2+]i alteration induced by acetylcholine (ACh) in TE671/RD cells with the special attention to ryanodine receptor (RyR) and inositol 1, 4, 5-trisphosphate receptor (IP3R). The change of [Ca2+]i was mediated by muscarinic type 3 (m3) AChR. Both phosphatidylinositol-specific phospholipase C blocker (U73122) and IP3R blocker (2-APB) inhibited ACh-induced [Ca2+]i elevation, suggesting that IP3 pathway is involved in [Ca2+]i alteration. Ryanodine and FK506 increased ACh-induced [Ca2+]i elevation, which was decreased by RyR blocker (ruthenium red). These results suggest that RyR and FK506 binding protein 12 kDa (FKBP12) complex was involved in [Ca2+]i change, and that TE671/RD cell line has a hybrid characteristic of smooth and skeletal muscles.
Property modification of an implant surface is known to influence the behavior of cells surrounding implant material. This study examined the osteogenic cell behavior on protein immobilized surface in vitro. Following plasma surface modification, fibronectin or bone morphogenetic protein-2 (BMP-2) was immobilized. The number of cells adhering to fibronectin-immobilized surface increased after 1 and 2 h of incubation compared with non-immobilized surface. Alkaline phosphatase activity and osteocalcin mRNA expression of the osteogenic cells on the BMP-2 immobilized surface was greater than that on the non-immobilized surface. This study demonstrated that protein can be immobilized to a polystyrene surface after treatment with O2 plasma and that the osteogenic cells surrounding a biomaterial can be controlled by the immobilization of protein to the biomaterial.
In humans and mice, the interaction between the breast cancer susceptibility protein, BRCA2, and RAD51 recombinase is essential for DNA repair by homologous recombination, the failure of this process can predispose to cancer. Cells with mutated BRCA2 are hypersensitive to ionizing radiation (IR) and exhibit defective DNA repair. Using yeast and mammalian two-hybrid assays, we demonstrate that canine Rad51 protein interacts specifically with the C-terminus of canine Brca2. In support of the biological significance of this interaction, we found that radiation-induced focus formation of Rad51 in COS-7 cells was compromised by forced expression of the C-terminus of canine Brca2. A similar result was obtained for the murine C-terminus. These data suggest that the C-terminal domain of canine Brca2 functions to bind Rad51 and that this domain contributes to the IR-induced assembly of the Rad51 complex in vivo.
Ultraviolet B (UVB) irradiation has been reported as one of causes of epidermal carcinoma and also one of immunosuppressive inducers associated with an up-regulated production of T helper (Th) 2-type cytokines such as interleukin-4 (IL-4) and IL-10. We investigated using a chronically UV-irradiated mouse model in this study whether liniment of interferon-gamma (IFN-γ), one of Th1-type cytokines, would be able to protect against UV-induced skin damage or not. We report here for the first time that liniment of IFN-γ promoted desirable skin reactions such as the inhibition of epidermal cell proliferation, the increment of soluble collagen levels and the inhibition of mast cell degranulation and that the dermal reactions after IFN-γ treatment bore resemblance to the reactions induced by UVA irradiation reported to induce Th1-type immune reactions. Thus, these results suggest that liniment of IFN-γ is effective to suppress skin damages after UV irradiation through regulation of the balance of Th1-type and Th2-type immune responses.
Proteases are thought to be potentially useful targets for developing medicines to control filariasis caused by parasitic nematodes. To screen cysteine proteases essential for viability of nematodes, fifteen cathepsin B/L-like genes of Caenorhabditis elegans, as a model of the parasitic nematodes, were interfered by RNAi. As a result, ∼100% embryonic lethality was observed only when Ce-cpl-1, encoding a cathepsin L-like protease, was knocked down. Subsequent attempts were made to identify the orthologs of Ce-cpl-1 in the parasitic nematode Brugia malayi by molecular cloning and sequencing of some EST clones. The sequences of five distinct open reading frames were identified, all of which are most homologous to Ce-CPL-1 in C. elegans. The consensus catalytic triad of cathepsin L-like proteases is conserved among four of the five predicted proteins. Phylogenetic analysis suggests that one of them, Bm-CPL-1, is closely related to the proteases from other filarial parasites. However, neither Bm-CPL-1 nor the other four predicted proteins belong to the same sub-branch of Ce-CPL-1 in the phylogenetic tree. In B. malayi, the functions of Ce-CPL-1 are presumably shared by some of the predicted proteases including Bm-CPL-1, although the possibility cannot be ruled out that B. malayi has an unknown cysteine protease more resembling Ce-CPL-1.