but does not enhance the expression of noninducible genes. Likewise, a 2-deoxy-D-glucose, a nonmetabolized sugar, is also effective. When a deletion was introduced into the virA gene in the region encoding the periplasmic portion of the VirA protein, enhancement by glucose disappeared, but vir expression was induced by acetosyringone in this mutant. These results suggest that these sugars directly enhance a signaling process initiated by phenolic inducers that results in an-increase in expression of the vir genes.

A series of substituted oxindole derivatives was synthesized and evaluated for growth hormone (GH) releasing activity using cultured rat pituitary cells. (+)-6-Carbamoyl-3-(2-chlorophenyl)-(2-diethylaminoethyl)-4-trifluoromethyloxindole (SM-130686, 37S) was found to have potent activity (EC(50) = 3.0 nM), while the other enantiomer 37R had reduced activity. The absolute configuration of 37S was confirmed by X-ray crystallographic analysis. Compound 37S showed a good pharmacokinetic profile in rats with 28% oral bioavailability at 10 mg/kg and excellent in vivo activity as evidenced by a significant weight gain after 4 days of oral administration at 10 mg/kg twice a day. Compound 37S displaced the binding of (35)S-MK-677 to human GHS-R with an IC(50) value of 1.2 +/- 0.2 nM.

Only 10-15% of unseparated thymocytes adhered to culture plates precoated with fibronectin (FN), but 60-70% of the CD4-8-(double-negative) thymocyte population did. This population bound to FN but not to collagen, laminin, or vitronectin. Its binding to FN was inhibited by anti-FN antibody or a mixture of synthetic peptides corresponding to two different sites of EN, termed the V10 sequence and the RGDS (Arg-Gly-Asp-Ser) sequence, which interact, respectively, with the VLA-4 and VLA-5 FN receptors expressed on T-lineage cells. CD4-8-thymocytes also adhered to a monolayer of a thymic stromal cell clone, MRL104.8a, that induces growth-maintenance and differentiation of such thymocytes. . Most important, blocking the adhesion of CD4-8-thymocytes to the thymic stromal cell monolayer resulted in potent inhibition of the differentiation of these thymocytes, which was otherwise induced toward the expression of CD4 and/or CD8 molecules. These results indicate that immature CD4-8-thymocytes adhere to thymic stromal cells preferentially through FN-FN receptor interaction and that such adhesion has a critical role in inducing and/or supporting the differentiation of these thymocytes.Lymphocytes express a number of surface molecules that mediate the adhesion of cells to one another or to extracellular matrix (ECM) components (1-4). For example, cell-cell interaction molecules such as CD2 and LFA-3 are used to augment specific adhesion of T cells to antigen-presenting cells (5), and other cell-cell interaction molecules function as homing receptors (6, 7). Thus, these cell surface molecules have been recognized as regulating the migration of lymphocytes as well as the interactions of activated lymphocytes during immune responses.Another type of cell adhesion mechanism involves the interaction of cells with ECM (2, 4). While the importance of such cell-cell interactions in developmental biology has been documented (8-12), few studies have investigated the role of cell-ECM adhesion mechanisms in lymphocyte development in lymphopoietic microenvironments such as the bone marrow and thymus. This may be ascribed to the lack of in vitro systems for such analyses and to the complexity arising from the expression of various forms of ECM molecules regulated in a tissue-and cell-specific fashion, as exemplified by fibronectin (FN) molecules (13-15). In this context, several lines of marrow and thymic stromal cells have been isolated to provide tools for analyzing the interaction between developing lymphocytes and stromal cells (16). We have also established a thymic stromal cell clone that is capable of providing an in vitro model for intrathymic T-cell development (17-19).The present study investigates the role of FN molecules expressed on thymic stromal cells in thymocyte-stromal cell adhesion and thymocyte differentiation. The results demonstrate that CD4-8-("double-negative") thymocytes adhere to thymic stromal cells through FN molecules on the stromal cells. Molecular analyses revealed that two adhesion sites, the classic...

No abstract

SM-130686, an oxindole derivative, is a novel orally active GH secretagogue (GHS) which is structurally distinct from previously reported GHSs such as MK-677, NN703 and hexarelin. SM-130686 stimulates GH release from cultured rat pituitary cells in a dose-dependent manner. Half-maximum stimulation was observed at a concentration of 6⋅3 3⋅4 nM. SM-130686-induced GH release was inhibited by a GHS antagonist, but not by a GHreleasing hormone antagonist. SM-130686 dosedependently inhibited the binding of radiolabeled ligand, 35 S-MK-677, to human GHS receptor 1a (IC 50 =1⋅2 nM). This indicates that SM-130686 stimulates GH release through the GHS receptor. The effect of a single oral administration of SM-130686 on GH release in pentobarbital-anesthetized rats was studied. After treatment with 10 mg/kg SM-130686, plasma GH concentrations measured by radioimmunoassay significantly increased, reaching a peak at 20-45 min, and remained above baseline during the experimental period (60 min). The anabolic effect of repetitive SM-130686 administration was studied in rats. Rats received 10 mg/kg SM-130686 orally twice a day and were weighed every day for 9 days. At day 9 there was a significant increase in both the body weight and the fat free mass (19⋅5 2⋅1 and 18⋅1 7⋅5 g respectively). Serum IGF-I concentration was also significantly elevated 6 h after the last dose of SM-130686. An endogenous GHS ligand for the GHS receptor has recently been identified from stomach extract and designated as ghrelin. The GH-releasing activity in vitro relative to ghrelin (100%) was about 52% for SM-130686. It is likely that SM-130686 is a partial agonist for the GHS receptor.In summary, we describe here an orally active GHS, SM-130686, which acts through the GHS receptor. Repetitive administration of SM-130686 to rats, similar to repetitive administration of GH, significantly increased the fat free mass by an amount almost equal to the gain in body weight.

benzamide (SMP-534) reduces extracellular matrix (ECM) production induced by transforming growth factor-␤ (TGF-␤) in vitro and prevents the accumulation of ECM in glomeruli in rat Thy-1 nephritis models. In this study, we examined the longterm effects of SMP-534 on renal insufficiency and glomerulosclerosis in db/db mice, which are models of type 2 diabetes. A diet containing SMP-534 was given to the mice from the age of 9 to 25 wk, and blood and urine analysis were performed at 8, 17, and 25 wk. At the end of study, kidney tissues were analyzed histologically. Treatment with SMP-534 dose dependently suppressed the increase of urinary albumin and type IV collagen excretion in db/db mice. The renal histological analysis showed that SMP-534 dose dependently suppressed the increase of mesangial expansion in the kidney. In the immunohistological analysis, fibronectin and type IV collagen expression were lower in SMP-534-treated db/db mice compared with vehicle-treated db/db mice. This study suggested that SMP-534 ameliorated the increase of ECM production in kidney of db/db mice, possibly through the inhibition of TGF-␤ action. Hence, antifibrotic agents such as SMP-534 might be a new therapeutic option for the treatment of diabetic nephropathy. urinary type IV collagen; diabetic nephropathy; antifibrotic agent; extracellular matrix; transforming growth factor-␤

Background/Aims: Diabetic nephropathy is the main cause of end-stage renal disease. Previously we have demonstrated that SMP-534 (an antifibrotic agent) prevents the development of diabetic nephropathy in db/db mouse and that combined treatment with SMP-534 and losartan (antihypertensive agents) markedly prevents the development of diabetic nephropathy compared with single treatment. SMP-534 or losartan was prophylactically administered to db/db mice before the onset of diabetic nephropathy. In the present study, we evaluated the efficacy of combined treatment when administration was started after the onset of diabetic nephropathy. Methods:db/db mice were raised untreated until 17 weeks of age, by which time increase of urinary albumin was noted, and then treated with SMP-534 and/or losartan for another 8 weeks. Biochemical and histological analyses were performed at 25 weeks of age. Results: Combined treatment with SMP-534 and losartan markedly prevented the increase ofurinary albumin and ameliorated the progression of mesangial matrix expansion, even when administration was started long after the increase of urinary albumin. Conclusion: The study results indicate that a combination of SMP-534 and losartan might be a valuable therapeutic approach for the treatment of diabetic nephropathy even when administration is started after the onset of diabetic nephropathy.

Background/Aims: Diabetic nephropathy is now the most common cause of end-stage renal disease. It is also clear that the current therapy, angiotensin II blockage, cannot prevent the progression of diabetic nephropathy. We had previously demonstrated that an antifibrotic agent, SMP-534, reduced extracellular matrix production induced by transforming growth factor-β in vitro, and that SMP-534 prevented renal fibrosis and urinary albumin in diabetic db/db mice via a nonantihypertensive mechanism. We expected that combined use of SMP-534 and losartan would produce a more highly renoprotective action. Methods: We examined the effects of combined treatment with SMP-534 and losartan on urinary albumin and glomerular fibrosis in db/db mice. Diet containing these agents was provided from age 9 to 25 weeks. Blood and urine analyses were performed at 8, 17, and 25 weeks. At the end of the study, kidney tissues were histologically analyzed. Results: SMP-534 significantly suppressed an increase in urinary albumin excretion and ameliorated the progression of glomerular fibrosis in db/db mice, whereas losartan did not. Combined treatment with SMP-534 and losartan markedly prevented the increase of urinary albumin excretion compared with treatment with either SMP-534 or losartan alone. In contrast, renal histological analysis revealed that combined treatment did not significantly prevent an increase of mesangial expansion in the kidney compared with treatment with SMP-534 alone. Conclusion: A combination of the two agents, SMP-534 and losartan, might be a valuable therapeutic approach for the treatment of diabetic nephropathy.