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David R Powell,1 Deon D Doree,1 Christopher M DaCosta,1 Kenneth A Platt,2 Robert Brommage,1 Lindsey Buhring,1 Jean-Pierre Revelli,1 Melanie K Shadoan1 1Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA; 2Department of Molecular Biology, Lexicon Pharmaceuticals, Inc., The Woodlands, TX, USACorrespondence: David R PowellDepartment of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc., 2445 Technology Forest Boulevard, The Woodlands, TX, 77381, USATel +1 713 249 3972Fax +1 281 863 8115Email dpowell@lexpharma.comPurpose: Humans with haploinsufficiency of GPR75, an orphan GPCR, are thin. Gpr75 knockout (KO) mice are also thin with improved glucose homeostasis. We wanted to confirm these findings in Gpr75 KO mice and determine whether decreased energy intake and/or increased energy expenditure contributed to the thin phenotype.Methods: Gpr75 KO mice were generated by homologous recombination. All studies compared female and male Gpr75 KO mice to their wild type (WT) littermates. Body composition was measured by DXA and QMR technologies. Glucose homeostasis was evaluated by measuring glucose and insulin levels during oral glucose tolerance tests (OGTTs). Food intake was measured in group-housed mice. In singly housed mice, energy expenditure was measured in Oxymax indirect calorimetry chambers, and locomotor activity was measured in Oxymax and Photobeam Activity System chambers.Results: In all 12 cohorts of adult female or male mice, Gpr75 KO mice had less body fat; pooled data showed that, compared to WT littermates (n = 103), Gpr75 KO mice (n = 118) had 49% less body fat and 4% less LBM (P < 0.001 for each). KO mice also had 8% less body fat at weaning (P < 0.05), and during the month after weaning as the thin phenotype became more exaggerated, Gpr75 KO mice ate significantly less than, but had energy expenditure and activity levels comparable to, their WT littermates. During OGTTs, Gpr75 KO mice showed improved glucose tolerance (glucose AUC 23% lower in females, P < 0.05, and 26% lower in males, P < 0.001), accompanied by significantly decreased insulin levels and significantly increased insulin sensitivity indices.Conclusion: Gpr75 KO mice are thin at weaning, are hypophagic as the thin phenotype becomes more exaggerated, and exhibit improved glucose tolerance and insulin sensitivity as healthy-appearing adults. These results suggest that inhibiting GPR75 in obese humans may safely decrease energy intake and body fat while improving glucose tolerance and insulin sensitivity.Keywords: obesity, diabetes, druggable, insulin sensitivity, healthy thinness

David R Powell,1 Jean-Pierre Revelli,1 Deon D Doree,1 Christopher M DaCosta,1 Urvi Desai,1 Melanie K Shadoan,1 Lawrence Rodriguez,2 Michael Mullens,2 Qi M Yang,1 Zhi-Ming Ding,1 Laura L Kirkpatrick,3 Peter Vogel,1 Brian Zambrowicz,1– 3 Arthur T Sands,1– 3 Kenneth A Platt,3 Gwenn M Hansen,3 Robert Brommage1 1Department of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, TX, USA; 2Department of Information Technology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USA; 3Department of Molecular Biology, Lexicon Pharmaceuticals, Inc, The Woodlands, Tx, USACorrespondence: David R PowellDepartment of Pharmaceutical Biology, Lexicon Pharmaceuticals, Inc, 2445 Technology Forest Boulevard, The Woodlands, Tx, 77381, USATel +1 713 249 3972Fax +1 281 863 8115Email dpowell@lexpharma.comPurpose: Obesity is a major public health problem. Understanding which genes contribute to obesity may better predict individual risk and allow development of new therapies. Because obesity of a mouse gene knockout (KO) line predicts an association of the orthologous human gene with obesity, we reviewed data from the Lexicon Genome5000TM high throughput phenotypic screen (HTS) of mouse gene KOs to identify KO lines with high body fat.Materials and Methods: KO lines were generated using homologous recombination or gene trapping technologies. HTS body composition analyses were performed on adult wild-type and homozygous KO littermate mice from 3758 druggable mouse genes having a human ortholog. Body composition was measured by either DXA or QMR on chow-fed cohorts from all 3758 KO lines and was measured by QMR on independent high fat diet-fed cohorts from 2488 of these KO lines. Where possible, comparisons were made to HTS data from the International Mouse Phenotyping Consortium (IMPC).Results: Body fat data are presented for 75 KO lines. Of 46 KO lines where independent external published and/or IMPC KO lines are reported as obese, 43 had increased body fat. For the remaining 29 novel high body fat KO lines, Ksr2 and G2e3 are supported by data from additional independent KO cohorts, 6 (Asnsd1, Srpk2, Dpp8, Cxxc4, Tenm3 and Kiss1) are supported by data from additional internal cohorts, and the remaining 21 including Tle4, Ak5, Ntm, Tusc3, Ankk1, Mfap3l, Prok2 and Prokr2 were studied with HTS cohorts only.Conclusion: These data support the finding of high body fat in 43 independent external published and/or IMPC KO lines. A novel obese phenotype was identified in 29 additional KO lines, with 27 still lacking the external confirmation now provided for Ksr2 and G2e3 KO mice. Undoubtedly, many mammalian obesity genes remain to be identified and characterized.Keywords: obesity, druggable, homologous recombination, gene trapping

David R Powell, Deon D Doree, Christopher M DaCosta, Kenneth A Platt, Gwenn M Hansen, Isaac van Sligtenhorst, Zhi-Ming Ding, Jean-Pierre Revelli, Robert Brommage Lexicon Pharmaceuticals Inc, The Woodlands, TX, 77381, USACorrespondence: David R PowellLexicon Pharmaceuticals Inc., 8800 Technology Forest Place, The Woodlands, TX 77381, USATel +1 281 863 3060Fax +1 281 863 8115Email dpowell@lexpharma.comPurpose: In humans, single nucleotide polymorphisms (SNPs) near the adjacent protein kinase D1 (PRKD1) and G2/M-phase-specific E3 ubiquitin protein ligase (G2E3) genes on chromosome 14 are associated with obesity. To date, no published evidence links inactivation of either gene to changes in body fat. These two genes are also adjacent on mouse chromosome 12. Because obesity genes are highly conserved between humans and mice, we analyzed body fat in adult G2e3 and Prkd1 knockout (KO) mice to determine whether inactivating either gene leads to obesity in mice and, by inference, probably in humans.Methods: The G2e3 and Prkd1 KO lines were generated by gene trapping and by homologous recombination methodologies, respectively. Body fat was measured by DEXA in adult mice fed chow from weaning and by QMR in a separate cohort of mice fed high-fat diet (HFD) from weaning. Glucose homeostasis was evaluated with oral glucose tolerance tests (OGTTs) performed on adult mice fed HFD from weaning.Results: Body fat was increased in multiple cohorts of G2e3 KO mice relative to their wild-type (WT) littermates. When data from all G2e3 KO (n=32) and WT (n=31) mice were compared, KO mice showed increases of 11% in body weight (P< 0.01), 65% in body fat (P< 0.001), 48% in % body fat (P< 0.001), and an insignificant 3% decrease in lean body mass. G2e3 KO mice were also glucose intolerant during an OGTT (P< 0.05). In contrast, Prkd1 KO and WT mice had comparable body fat levels and glucose tolerance.Conclusion: Significant obesity and glucose intolerance were observed in G2e3, but not Prkd1, KO mice. The conservation of obesity genes between mice and humans strongly suggests that the obesity-associated SNPs located near the human G2E3 and PRKD1 genes are linked to variants that decrease the amount of functional human G2E3.Keywords: glucose tolerance, gene trap, homologous recombination, Prkd1, PRKD1, SNP

Introduction: Contrast computer tomography (CT) scanning is the investigation of choice for the further assessment of suspected cystic congenital lung lesions (CCLL). Its use to identify the presence of anomalous feeding vessels supplying the lesion is well documented, but data regarding its accuracy is limited. This study compares CT results to operative and pathological findings to determine the accuracy of CT in identifying these anomalous vessels. Methods: 51 consecutive cases of cystic congenital lung lesions managed in one hospital by a single consultant were reviewed. All cases had contrast CT scans performed preoperatively, as standard practice in this institution. We compared the results of these CT scans to the macroscopic appearance at surgery and histological findings postoperatively. We also compared the results of 2 CT protocols used in our institution between 1999-2007 and 2007-2009, respectively. Results: Anomalous vessels were reported on CT in 9 cases. All but 1 had concordant operative and pathological findings. In the remaining 42 cases, no anomalous vessels were seen on CT. Of these, 9 cases were found to have an anomalous blood supply at surgery, 6 of which were hybrid lesions and 3 isolated sequestrations. The specificity of CT in identifying feeding vessels in the study was 97% (95% CI: 0.83-0.99) and the sensitivity was 47% (95% CI: 0.23-0.71). The positive predictive value was 89% (95% CI: 0.50-0.99) and negative predictive value 79% (95% CI: 0.62-0.89). The most recent protocol yielded an improved sensitivity of 75% (95% CI: 0.22-0.98) and a specificity of 100% (95% CI: 0.46-1.0) with a 100% (95% CI: 0.31-1.0) positive and 83% (95% CI: 0.36-0.99) negative predictive value. Conclusion: CT is a specific investigation for identifying anomalous vessels in CCLL but lacks sensitivity, leading to a relatively low negative predictive value. This emphasises the need in every case to look for anomalous vessels at surgery to avoid morbidity and potential mortality. An improved protocol for CT scans leads to improved specificity and sensitivity and predictive values. [ABSTRACT FROM AUTHOR]

GREMLIN 2 (GREM2)—formerly, protein related to Dan and cerberus (PRDC)—is a potent antagonist of the bone morphogenetic proteins 2 and 4, but little else in known about its functions. We found that Grem2-/- mice developed small deformed mandibular and maxillary incisors, indicating that GREMLIN2 is required for normal tooth morphogenesis. Although DEXA scans suggested that bone mineral density might be increased in Grem2-/- mice, histology did not reveal any evident bone phenotype. Grem2-/- mice did not display any other notable phenotypes evaluated in a high-throughput screening process that encompassed a range of immunologic, metabolic, ophthalmic, and behavioral parameters. Our findings indicate that Grem2 can be added to the growing list of genes that affect tooth development in mice. [ABSTRACT FROM PUBLISHER]