Design and synthesis of orally active benzamide derivatives as potent serotonin 4 receptor agonist

A series of 4-amino-5-chloro-2-methoxy-N-(piperidin-4-ylmethyl)benzamide derivatives bearing an aralkylamino, alkylamino, benzoyl or phenylsulfonyl group at its side chain part at the 1-position on the piperidine ring was synthesized. They were evaluated for serotonin 4 (5-HT(4)) receptor agonist activity by testing their ability to contract the isolated guinea-pig ascending colon. 4-Amino-5-chloro-2-methoxy-N-[1-[5-(1-methylindol-3-ylcarbonylamino)pentyl]piperidin-4-ylmethyl]benzamide (1a, Y-34959) and its related compounds possessed favorable pharmacological profiles for gastrointestinal motility. Unfortunately, the compound 1a showed low bioavailability when given orally presumably due to its poor intestinal absorption rate. Replacement of the 1-methylindol-3-yl carbonylamino moiety of 1a with an aralkylamino (or alkylamino) group did not improve the intestinal absorption rate. Replacement of the 1-methylindol-3-ylcarbonylamino moiety with a benzoyl or phenylsulfonyl group increased the intestinal absorption rate compared with 1a. These compounds revealed good pharmacological profiles for gastrointestinal motility and were superior to 1a in oral bioavailability.     

Bradykinin-induced proinflammatory signaling mechanisms

Intravital microscopic techniques were used to examine the mechanisms underlying bradykinin-induced leukocyte/endothelial cell adhesive interactions (LECA) and venular protein leakage (VPL) in single postcapillary venules of the rat mesentery. The effects of bradykinin superfusion to increase LECA and VPL were prevented by coincident topical application of either a bradykinin-B(2) receptor antagonist, a cell-permeant superoxide dismutase (SOD) mimetic or antioxidant, or inhibitors of cytochrome P-450 epoxygenase (CYPE) or protein kinase C (PKC) but not by concomitant treatment with either SOD, a mast cell stabilizer, or inhibitors of nitric oxide synthase, cyclooxygenase, xanthine oxidase, NADPH oxidase, or platelet-activating factor. Immunoneutralizing P-selectin or intercellular adhesion molecule-1 (ICAM-1) completely prevented bradykinin-induced leukocyte adhesion and emigration but did not affect VPL. On the other hand, stabilization of F-actin with phalloidin prevented bradykinin-induced leukocyte emigration and VPL but did not alter leukocyte adhesion. These data indicate that bradykinin induces LECA in rat mesenteric venules via a B(2)-receptor-initiated, CYPE-, oxidant- and PKC-mediated, P-selectin- and ICAM-1-dependent mechanism. Bradykinin also produced VPL, an effect that was initiated by stimulation of B(2) receptors and involved CYPE and PKC activation, oxidant generation, and cytoskeletal reorganization but was independent of leukocyte adherence and emigration.     

Glycoprotein Nonmetastatic Melanoma B (Gpnmb)-Positive Macrophages Contribute to the Balance between Fibrosis and Fibrolysis during the Repair of Acute Liver Injury in Mice

Background and aims

Glycoprotein nonmetastatic melanoma B (Gpnmb), a transmembrane glycoprotein that is expressed in macrophages, negatively regulates inflammation. We have reported that Gpnmb is strongly expressed in the livers of rats fed a choline-deficient, L-amino acid-defined (CDAA) diet. However, the role of macrophage-expressed Gpnmb in liver injury is still unknown. This study aimed to clarify the characteristics of infiltrating macrophages that express Gpnmb, and the involvement of Gpnmb in the repair process in response to liver injury.

Methods

C57BL/6J, DBA/2J [DBA] and DBA/2J-Gpnmb⁺ [DBA-g+] mice were treated with a single intraperitoneal injection of carbon tetrachloride (CCl₄) at a dose of 1.0 mL/kg body weight. Mice were sacrificed at predetermined time points, followed by measurement of serum alanine aminotransferase (ALT) levels and histological examination. Expression of Gpnmb, pro-/anti-inflammatory cytokines, and profibrotic/antifibrotic factors were examined by quantitative RT-PCR and/or Western blotting. Immunohistochemistry, fluorescent immunostaining and flow cytometry were used to determine the expression of Gpnmb, CD68, CD11b and α-SMA, phagocytic activity, and the presence of apoptotic bodies. We used quantitative RT-PCR and ELISA to examine TGF-β and MMP-13 expression and the concentrations and supernatants of isolated infiltrating hepatic macrophages transfected with siGpnmb.

Results

In C57BL/6J mice, serum ALT levels increased at two days after CCl₄ injection and decreased at four days. Gpnmb expression in the liver was stimulated four days after CCl₄ injection. Histological examination and flow cytometry showed that Gpnmb-positive cells were almost positive for CD68-positive macrophages, contained engulfed apoptotic bodies and exhibited enhanced phagocytic activity. Isolated infiltrating hepatic macrophages transfected with siGpnmb showed high MMP-13 secretion. There was no significant difference in the magnitude of CCl₄-induced liver injury between DBA-g+ and DBA mice. However, hepatic MMP-13 expression, as well as α-SMA expression and collagen production, increased significantly in DBA-g+ compared with DBA mice.

Conclusions

Gpnmb-positive macrophages infiltrate the liver during the recovery phase of CCl₄–induced acute liver injury and contribute to the balance between fibrosis and fibrolysis in the repair process following acute liver injury.     

Senescence marker protein 30 (SMP30)/regucalcin (RGN) expression decreases with aging, acute liver injuries and tumors in zebrafish

Senescence marker protein 30 (SMP30)/regucalcin (RGN) is known to be related to aging, hepatocyte proliferation and tumorigenesis. However, expression and function of non-mammalian SMP30/RGN is poorly understood. We found that zebrafish SMP30/RGN mRNA expression decreases with aging, partial hepatectomy and thioacetamide-induced acute liver injury. SMP30/RGN expression was also greatly decreased in a zebrafish liver cell line. In addition, we induced liver tumors in adult zebrafish by administering diethylnitrosamine. Decreased expression was observed in foci, hepatocellular carcinomas, cholangiocellular carcinomas and mixed tumors as compared to the surrounding area. We thus showed the importance of SMP30/RGN in liver proliferation and tumorigenesis.     

Crystallographic analysis reveals octamerization of viroplasm matrix protein P9-1 of Rice black streaked dwarf virus

The P9-1 protein of Rice black streaked dwarf virus accumulates in viroplasm inclusions, which are structures that appear to play an important role in viral morphogenesis and are commonly found in viruses in the family Reoviridae. Crystallographic analysis of P9-1 revealed structural features that allow the protein to form dimers via hydrophobic interactions. Each dimer has carboxy-terminal regions, resembling arms, that extend to neighboring dimers, thereby uniting sets of four dimers via lateral hydrophobic interactions, to yield cylindrical octamers. The importance of these regions for the formation of viroplasm-like inclusions was confirmed by the absence of such inclusions when P9-1 was expressed without its carboxy-terminal arm. The octamers are vertically elongated cylinders resembling the structures formed by NSP2 of rotavirus, even though there are no significant similarities between the respective primary and secondary structures of the two proteins. Our results suggest that an octameric structure with an internal pore might be important for the functioning of the respective proteins in the events that occur in the viroplasm, which might include viral morphogenesis.     

Alkaline detergent enzymes from alkaliphiles: enzymatic properties, genetics, and structures

The cleaning power of detergents seems to have peaked; all detergents contain similar ingredients and are based on similar detergency mechanisms. To improve detergency, modern types of heavy-duty powder detegents and automatic dishwasher detergents usually contain one or more enzymes, such as protease, amylase, cellulase, and lipase. Alkaliphilic Bacillus strains are often good sources of alkaline extracellular enzymes, the properties of which fulfil the essential requirements for enzymes to be used in detergents. We have isolated numbers of alkaliphilic Bacillus that produce such alkaline detergent enzymes, including cellulase (CMCase), protease, α-amylase, and debranching enzymes, and have succeeded in large-scale industrial production of some of these enzymes. Here, we describe the enzymatic properties, genetics, and structures of the detergent enzymes that we have developed. Received: January 22, 1998 / Accepted: February 16, 1998