The mouse aspartyl ␤-hydroxylase gene (Asph, BAH) has been cloned and characterized. The mouse BAH gene spans 200 kilobase pairs of genomic DNA and contains 24 exons. Of three major BAH-related transcripts, the two largest (6,629 and 4,419 base pairs) encode fulllength protein and differ only in the use of alternative polyadenylation signals. The smallest BAH-related transcript (2,789 base pairs) uses an alternative 3 terminal exon, resulting in a protein lacking a catalytic domain. Evolutionary conservation of this noncatalytic isoform of BAH (humbug) is demonstrated in mouse, man, and Drosophila. Monoclonal antibody reagents were generated, epitope-mapped, and used to definitively correlate RNA bands on Northern blots with protein species on Western blots. The gene for mouse junctin, a calsequestrin-binding protein, was cloned and characterized and shown to be encoded from the same locus. When expressed in heart tissue, BAH/humbug preferably use the first exon and often the fourth exon of junctin while preserving the reading frame. Thus, three individual genes share common exons and open reading frames and use separate promoters to achieve differential expression, splicing, and function in a variety of tissues. This unusual form of exon sharing suggests that the functions of junctin, BAH, and humbug may be linked.

OBJECTIVE-We have developed a novel platform for display and delivery of bioactive peptides that links the biological properties of the peptide to the pharmacokinetic properties of an antibody. Peptides engineered in the MIMETIBODY platform have improved biochemical and biophysical properties that are quite distinct from those of Fc-fusion proteins. CNTO736 is a glucagon-like peptide 1 (GLP-1) receptor agonist engineered in our MIMETIBODY platform. It retains many activities of native GLP-1 yet has a significantly enhanced pharmacokinetic profile. Our goal was to develop a long-acting GLP-1 receptor agonist with sustained efficacy. RESEARCH DESIGN AND METHODS-In vitro and in vivo activity of CNTO736 was evaluated using a variety of rodent cell lines and diabetic animal models.RESULTS-Acute pharmacodynamic studies in diabetic rodents demonstrate that CNTO736 reduces fasting and postprandial glucose, decreases gastric emptying, and inhibits food intake in a GLP-1 receptor-specific manner. Reduction of food intake following CNTO736 dosing is coincident with detection of the molecule in the circumventricular organs of the brain and activation of c-fos in regions protected by the blood-brain barrier. Diabetic rodents dosed chronically with CNTO736 have lower fasting and postprandial glucose and reduced body weight. CONCLUSIONS-Takentogether, our data demonstrate that CNTO736 produces a spectrum of GLP-1 receptor-dependent actions while exhibiting significantly improved pharmacokinetics relative to the native GLP-1 peptide. Diabetes 57: [1926][1927][1928][1929][1930][1931][1932][1933][1934] 2008 D rug development strategies for therapeutic peptides continue to be challenging despite advances in technologies such as pegylation and lipidation (1-4). Although important biological processes are regulated by peptides, successful development of peptide drugs has been limited and transformation of a metabolically labile peptide into a drug remains challenging. In contrast, considerable advances have been made in the development of antibody therapeutics (5,6). A technology that could link the activity of a target peptide with the pharmacokinetic characteristics of an antibody would be a valuable addition to tools available for drug discovery. To address this need, we developed the MI-METIBODY platform as a novel technology for the display and delivery of bioactive peptides. Using protein design tools, we linked an antibody Fc domain to a bioactive glucagon-like peptide 1 (GLP-1) analog and engineered the construct for optimal biochemical and biophysical properties.GLP-1 is a 30 -amino acid peptide secreted from L-cells of the intestine following nutrient ingestion (7-10). GLP-1 is rapidly degraded in vivo with a half-life of Ͻ2 min and cleared via the kidney (11,12). When circulating glucose concentrations are elevated, GLP-1 increases insulin and decreases glucagon secretion from the pancreas and slows gastric emptying, thereby reducing glucose appearance in the circulation and enhancing glucose clearance from the circul...

Alternative splicing of the human ␤-aspartyl (asparaginyl) hydroxylase (BAH) gene results in the expression of humbug, a truncated form of BAH that lacks the catalytic domain of the enzyme. Overexpression of BAH and humbug has been associated with a variety of human cancers, and although humbug lacks enzymatic activity, it is expressed at levels comparable with that of BAH in various cancer cell lines. Phosphorothioate antisense oligonucleotides (ONs) were designed to dissect out the function of these hydroxylase protein isoforms. In A549 cells, these ONs differentially down-regulated BAH and humbug at the mRNA and protein level. Phosphorothioate ON uptake and antisense studies were conducted in parallel in nude mice bearing A549 tumor xenografts. Microscopic examination of the tumor after administration of a fluorescein-labeled ON showed strong labeling of the outer layers of the tumor connective tissue but cells within the interior of the tumor were sparsely labeled. A modest but significant effect on tumor growth was observed in animals treated with an antisense ON directed against both BAH and humbug transcripts. However, Northern analysis of tumor RNA did not indicate a down-regulation of the targeted mRNA species. These results demonstrate the successful development of antisense ONs that selectively differentiate between the closely related ␤-hydroxylase protein isoforms. However, determination of the biological function of these proteins in vivo was limited by the poor uptake properties of phosphorothioate ONs in A549 tumors.

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Patients treated with recombinant human Epo demonstrate an improvement in insulin sensitivity. We aimed to investigate whether CNTO 530, a novel Epo receptor agonist, could affect glucose tolerance and insulin sensitivity. A single administration of CNTO 530 significantly and dose-dependently reduced the area under the curve in a glucose tolerance test in diet-induced obese and diabetic mice after 14, 21, and 28 days. HOMA analysis suggested an improvement in insulin sensitivity, and this effect was confirmed by a hyperinsulinemic-euglycemic clamp. Uptake of 14C-2-deoxy-D-glucose indicated that animals dosed with CNTO 530 transported more glucose into skeletal muscle and heart relative to control animals. In conclusion, CNTO530 has a profound effect on glucose tolerance in insulin-resistant rodents likely because of improving peripheral insulin sensitivity. This effect was observed with epoetin-α and darbepoetin-α, suggesting this is a class effect, but the effect with these compounds relative to CNTO530 was decreased in duration and magnitude.