Reduced body weight in male Tspan8-deficient mice

• Published in: International Journal of Obesity 2011-04, Vol.35 (4), p.605-617
• Main Authors: Champy, M.F, Le Voci, L, Selloum, M, Peterson, L.B, Cumiskey, A.M, Blom, D
• Format: Article
• Language: English
• Subjects: 631/1647/2217/2138; 692/699/2743/137/773; Ablation; Animals; Antigens, Neoplasm - genetics; Biological and medical sciences; Body weight; Body Weight - physiology; Bone density; Bone mineral density; Cardiology and cardiovascular system; Diabetes; Diabetes Mellitus, Type 2 - genetics; Diabetes Mellitus, Type 2 - metabolism; Diabetes. Impaired glucose tolerance; Diet; Disease; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Epidemiology; Etiopathogenesis. Screening. Investigations. Target tissue resistance; fasting; Female; Genes; Genetic aspects; Genome-Wide Association Study; Genomes; Glucose; glucose tolerance tests; Health Promotion and Disease Prevention; high carbohydrate diet; Human health and pathology; humans; Insulin; insulin resistance; Insulin Resistance - genetics; Insulin Resistance - physiology; Internal Medicine; lean body mass; Life Sciences; loci; Male; Males; Medical sciences; Medicine; Medicine & Public Health; Membrane Glycoproteins - deficiency; Membrane Glycoproteins - genetics; Metabolic Diseases; Metabolism; Mice; Mice, Inbred C57BL; Mice, Knockout; noninsulin-dependent diabetes mellitus; Obesity; Obesity - genetics; Obesity - metabolism; original-article; pancreas; phosphorus; Physiological aspects; Physiology; Proteins; Public Health; risk; Risk factors; Sex Factors; Tetraspanins; Tissues; Type 2 diabetes; Weight control; weight gain
• ISSN: 0307-0565; 1476-5497; 0307-0565
• DOI: 10.1038/ijo.2010.165

Objective: The gene TSPAN8 was recently identified in a genome-wide association study as the most likely causal gene in a locus that was correlated with the risk of type 2 diabetes (T2D) in northern European individuals. To assess whether Tspan8 is the actual T2D-causal gene in this locus, we ablated its expression in mice and determined the consequences of this ablation on a multitude of metabolic traits. Results: We found that genetic ablation of Tspan8 in mice results in a reduction (−15.6%) in the body weight of males fed a normal chow diet and that this deficiency results in a resistance to body weight gain (−13.7%) upon feeding a high fat and high carbohydrate diet. The differences in body weight could only be detected in male mice and were the consequence of both a decrease in fat deposition, and a decrease in lean body mass (16.9 and 11%, respectively). In spite of the significant body weight difference, no changes in fasting insulin and glucose levels could be detected in Tspan8 knockout mice, nor could we identify changes in the clearance of glucose or sensitivity to insulin in oral glucose tolerance test and intraperitoneal insulin sensitivity test studies, respectively. In addition, male Tspan8 knockout mice showed significantly lower bone mineral density and phosphorus levels (6.2 and 16.6%, respectively). Expression of Tspan8 in mouse was highest in digestive tissues, but virtually absent from the pancreas. In contrast, expression of human TSPAN8 was substantial in digestive tissues, as well as pancreatic cells. Conclusions: Our results argue for a role for Tspan8 in body-weight regulation in males, but do not show differences in T2D-associated traits that were anticipated from previous human genome-wide association studies. Differences in Tspan8 expression levels in mouse and human tissues suggest that Tspan8 could fulfill different or additional physiological functions in these organisms.