In Vitro and In Vivo Antagonism of a G Protein-Coupled Receptor (S1P3) with a Novel Blocking Monoclonal Antibody

Background: S1P 3 is a lipid-activated G protein-couple receptor (GPCR) that has been implicated in the pathological processes of a number of diseases, including sepsis and cancer. Currently, there are no available high-affinity, subtypeselective drug compounds that can block activation of S1P3. We have developed a monoclonal antibody (7H9) that specifically recognizes S1P3 and acts as a functional antagonist. Methodology/Principal Findings: Specific binding of 7H9 was demonstrated by immunocytochemistry using cells that over-express individual members of the S1P receptor family. We show, in vitro, that 7H9 can inhibit the activation of S1P3mediated cellular processes, including arrestin translocation, receptor internalization, adenylate cyclase inhibiton, and calcium mobilization. We also demonstrate that 7H9 blocks activation of S1P3 in vivo, 1) by preventing lethality due to systemic inflammation, and 2) by altering the progression of breast tumor xenografts. Conclusions/Significance: We have developed the first-reported monoclonal antibody that selectively recognizes a lipidactivated GPCR and blocks functional activity. In addition to serving as a lead drug compound for the treatment of sepsi

Neudesin in obesity and type 2 diabetes mellitus: the effect of acute fasting and weight reducing interventions

Helena Kratochvilova,1–3 Zdenka Lacinova,1–3 Jana Klouckova,1–3 Petra Kavalkova,2,3 Anna Cinkajzlova,1–3 Pavel Trachta,4 Jarmila Krizova,4 Marek Benes,5 Karin Dolezalova,6 Martin Fried,6 Zuzana Vlasakova,7 Terezie Pelikanova,7 Julius Spicak,5 Milos Mraz,2,3,7 Martin Haluzik1–3,7 1Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; 2Department of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University, Prague, Czech Republic; 3Department of Medical Biochemistry and Laboratory Diagnostics, General University Hospital, Prague, Czech Republic; 4Third Department of Medicine, Department of Endocrinology and Metabolism, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic; 5Hepatogastroenterology Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic; 6Department of Surgery, OB Clinic, Prague, Czech Republic; 7Diabetes Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic Context: Neudesin has recently been identified as a novel regulator of energy expenditure in experimental animals; however, its role in humans remains unexplored.Objective: The aim of this study was to assess the effects of obesity and type 2 diabetes mellitus (T2DM) along with selected weight reducing interventions on serum neudesin levels and adipose tissue mRNA expression.Patients and methods: Fifteen obese subjects with T2DM undergoing endoscopic duodenal-jejunal bypass liner (DJBL) implantation, 17 obese subjects (11 with T2DM, 6 without T2DM) scheduled for gastric plication (GP), 15 subjects with functional hypoglycemia subjected to 72-hour acute fasting (AF), and 12 healthy controls were included in the study.Results: Baseline neudesin levels were comparable between all groups. DJBL increased neudesin at 6 and 10 months after the procedure (1.77±0.86 vs 2.28±1.27 vs 2.13±1.02 ng/mL, P=0.001 for baseline vs 6 vs 10 months) along with reduction in body weight and improvement of HbA1c without any effect on neudesin mRNA expression in subcutaneous adipose tissue. Conversely, GP did not affect neudesin levels despite marked reduction in body weight and improvement of HbA1c. In contrast, AF decreased neudesin levels during the entire period (1.74±0.54 vs 1.46±0.48 ng/mL, P=0.001 for baseline vs 72 hours) with no impact of subsequent re-alimentation on neudesin concentrations.Conclusion: Neudesin levels are differentially regulated during AF and chronic weight reduction induced by DJBL or GP. Further studies are needed to assess its possible significance in energy homeostasis regulation in humans. Keywords: neudesin, obesity, type 2 diabetes mellitus, bariatric surgery, acute fasting, weight reduction, energy homeostasi