Human coronaviruses (HCV) in two serogroups represented by HCV-229E and HCV-OC43 are an important cause of upper respiratory tract infections. Here we report that human aminopeptidase N, a cell-surface metalloprotease on intestinal, lung and kidney epithelial cells, is a receptor for human coronavirus strain HCV-229E, but not for HCV-OC43. A monoclonal antibody, RBS, blocked HCV-229E virus infection of human lung fibroblasts, immunoprecipitated aminopeptidase N and inhibited its enzymatic activity. HCV-229E-resistant murine fibroblasts became susceptible after transfection with complementary DNA encoding human aminopeptidase N. By contrast, infection of human cells with HCV-OC43 was not inhibited by antibody RBS and expression of aminopeptidase N did not enhance HCV-OC43 replication in mouse cells. A mutant aminopeptidase lacking the catalytic site of the enzyme did not bind HCV-229E or RBS and did not render murine cells susceptible to HCV-229E infection, suggesting that the virus-binding site may lie at or near the active site of the human aminopeptidase molecule.

The BALB/c (6,7). Resistance of SJL/J mice to MHV infection is a recessive trait mapped to the Hv-2 locus on mouse chromosome 7 (8, 9). Membranes from intestine and liver of SJL/J mice do not bind MHV or anti-receptor mAb CC1, suggesting that resistance to infection is due to absence of a functional virus receptor (3, 4). SJL/J mice express a 100-to 110-kDa glycoprotein antigenically related to the MHV receptor. Because this SJL/J receptor homolog binds neither MHV-A59 virus nor anti-receptor mAb CC1, we postulated that it has a mutation affecting the domain of the glycoprotein that normally would bind MHV and mAb CC1 (4). In this communication we demonstrate that the MHV receptor glycoprotein of BALB/c and Swiss Webster mice and its SJL/J homolog are members of the carcinoembryonic antigen (CEA) family of glycoproteins in the immunoglobulin superfamily.

Background. Endothelial cells produce a number of substances, collectively termed endothelium-derived relaxing factor (EDRF), that promote local relaxation of vascular smooth muscle. Although studies have demonstrated defects in endothelium-dependent vasodilation in animal models of hypertension, atherosclerosis, and heart failure, there are only limited data from human subjects because of the difficulty in obtaining fresh vascular segments.Methods and Results. To address the hypothesis that endothelium-dependent vasodilation is attenuated in patients with heart failure, we measured forearm blood flow responses to the intra-arterial administration of methacholine, a known stimulus of EDRF release through muscarinic receptors. In 14 normal subjects, a dosage range of methacholine increased forearm blood flow by 5.26±+0.63, 10.50±0.63, and 13.22±0.86 ml/min/100 ml forearm volume (FAV); these responses were 1.98+±0.46, 5.48±0.79, and 8.50±+1.53 ml/min/100 ml FAV in 14 patients with heart failure. When pooled over all doses, the responses were strikingly less in the patients with heart failure (5.32+±0.31 versus 9.52+±0.60 ml/min/100 ml FAV; p=0.0003). In a second study, the average difference in forearm blood flow responses between patients with heart failure and normal subjects with methacholine was significantly greater than the average difference between the groups with nitroprusside (4.04±1.10 versus 2.20±0.71 ml/min/100 ml FAV; p=0.04). The decreased methacholine responses in the patients with heart failure were not related to age (r= 0.39; p=NS) or etiology because there was no difference in the responses between patients with ischemic heart disease and those with idiopathic cardiomyopathy.Conclusions. These data suggest that endothelium-dependent vasodilation is attenuated in patients with heart failure. Although the mechanisms of the decreased endothelium-dependent responses in heart failure are not known, this impaired local vasodilation may contribute to characteristic of heart failure. (Circulation

The cellular receptor for murine coronavirus mouse hepatitis virus (MHV)-A59 is a member of the carcinoembryonic antigen (CEA) family of glycoproteins in the immunoglobulin superfamily. We isolated a cDNA clone (MHVR1) encoding the MHV receptor. The sequence of this clone predicts a 424-amino-acid glycoprotein with four immunoglobulinlike domains, a transmembrane domain, and a short intracytoplasmic tail. MHVR, is closely related to the murine CEA-related clone mmCGM, (Mus musculus carcinoembryonic antigen gene family member). Western blot (immunoblot) analysis performed with antireceptor antibodies detected a glycoprotein of 120 kDa in BHK cells stably transfected with MHVR,. This corresponds to the size of the MHV receptor expressed in mouse intestine and liver. Human and hamster fibroblasts transfected with MHVR1 became susceptible to infection with MHV-A59. Like MHV-susceptible mouse fibroblasts, the MHVR,-transfected human and hamster cells were protected from MHV infection by pretreatment with monoclonal antireceptor antibody CCL. Thus, the 110to 120-kDa CEA-related glycoprotein encoded by

A low KCCQ score is an independent predictor of poor prognosis in outpatients with HF.

Fungi treated with DNA methyltransferase and histone deacetylase inhibitors exhibited natural product profiles with enhanced chemical diversity demonstrating that small-molecule epigenetic modifiers are effective tools for rationally controlling the native expression of fungal biosynthetic pathways and generating new biomolecules.

Plant specialized metabolism serves as a rich resource of biologically active molecules for drug discovery. The acylated flavonol glycoside montbretin A (MbA) and its precursor myricetin 3--(6'--caffeoyl)-glucosyl rhamnoside (mini-MbA) are potent inhibitors of human pancreatic α-amylase and are being developed as drug candidates to treat type-2 diabetes. MbA occurs in corms of the ornamental plant montbretia (), but a system for large-scale MbA production is currently unavailable. Biosynthesis of MbA from the flavonol myricetin and MbA accumulation occur during early stages of corm development. We established myricetin 3--rhamnoside (MR), myricetin 3--glucosyl rhamnoside (MRG), and mini-MbA as the first three intermediates of MbA biosynthesis. Contrasting the transcriptomes of young and old corms revealed differentially expressed UDP-sugar-dependent glycosyltransferases (UGTs) and BAHD-acyltransferases (BAHD-ATs). UGT77B2 and UGT709G2 catalyze the consecutive glycosylation of myricetin to produce MR and of MR to give MRG, respectively. In addition, two BAHD-ATs, CcAT1 and CcAT2, catalyze the acylation of MRG to complete the formation of mini-MbA. Transcript profiles of UGT77B2, UGT709G2, CcAT1, and CcAT2 during corm development matched the metabolite profile of MbA accumulation. Expression of these enzymes in wild tobacco () resulted in the formation of a surrogate mini-MbA, validating the potential for metabolic engineering of mini-MbA in a heterologous plant system.

The receptor for mouse hepatitis virus strain A59 (MHV-A59) is a 110to 120-kilodalton (kDa) glycoprotein which is expressed in MHV-susceptible mouse strains on the membranes of hepatocytes, intestinal epithelial cells, and macrophages. SJL/J mice, which are highly resistant to MHV-A59, were previously shown to lack detectable levels of receptor by using either solid-phase virus receptor assays or binding of a monoclonal anti-receptor antibody (MAb) which blocks infection of MHV-susceptible mouse cells. This MAb was used for affinity purification of the receptor glycoprotein from livers of MHV-susceptible Swiss Webster mice. The MHV receptor and an antigenically related protein of 48 to 58 kDa were copurified and then separated by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first 15 amino acids of the receptor were sequenced, and a synthetic peptide of this amino acid sequence was prepared. Rabbit antiserum made against this peptide bound to the MHV receptor glycoprotein and the 48to 58-kDa protein from livers of MHVsusceptible BALB/c mice and Swiss Webster mice and from the intestinal brush border of BALB/c mice. In immunoblots of intestinal brush border and hepatocyte membranes of MHV-resistant SJL/J mice, the antibody against the amino terminus of the receptor identified proteins that are 5 to 10 kDA smaller than the MHV receptor and the 48to 58-kDa related protein from Swiss Webster or BALB/c mice. Thus, SJL/J mice express a protein which shares some sequence homology with the MHV receptor but which lacks virus-binding activity and is not recognized by the blocking anti-receptor MAb. These results suggest that resistance of SJL/J mice to MIHV-A59 may be due to absence or mutation of the virus-binding domain in the nonfunctional receptor homolog in SJL/J mice. Mouse hepatitis virus (MHV) is a murine coronavirus which causes inapparent enteric or respiratory infection, diarrhea, hepatitis, and acute and chronic demyelinating diseases of the central nervous system (33). Classic studies by Bang and co-workers showed that mouse strains differ markedly in their susceptibility to MHV and that mouse strain susceptibility correlates with permissiveness for MHV replication in peritoneal macrophages cultured from the different mouse strains (2). A single recessive gene, hv-1, was associated with resistance of C3H mice to MHV-2 (34). A wide variety of mouse strains has been tested for susceptibility to several of the many strains of MHV which differ in virulence and tissue tropism (1, 3, 8-10, 16, 18, 19, 26, 27). SJL/J mice and/or peritoneal macrophages cultured from them are highly resistant to infection with the neurotropic strain MHV-JHM and the hepatotropic strain MHV-A59. This resistance trait has been mapped to a single recessive gene at the hv-2 locus near the svp-2 and albino loci on mouse chromosome 7 (15-17, 26). A solid-phase virusbinding assay was used to show that a receptor for MHV-A59 is present on the brush border membranes of enterocytes and hepatocytes from MHV-susceptible...