Gene Profiling of Human Adipose Tissue During Evoked Inflammation In Vivo

Gene Profiling of Human Adipose Tissue During Evoked Inflammation In Vivo Rachana Shah 1 , Yun Lu 2 , Christine C. Hinkle 3 , Fiona C. McGillicuddy 3 , Roy Kim 1 , 4 , Sridhar Hannenhalli 4 , 5 , Thomas P. Cappola 3 , 4 , Sean Heffron 3 , XingMei Wang 2 , Nehal N. Mehta 3 , Mary Putt 2 and Muredach P. Reilly 3 , 4 1 Division of Pediatric Endocrinology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; 2 Center for Clinical Epidemiology and Biostatistics, Philadelphia, Pennsylvania; 3 Cardiovascular Institute, Philadelphia, Pennsylvania; 4 Institute for Diabetes Obesity and Metabolism, Philadelphia, Pennsylvania; 5 Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania. Corresponding author: Muredach P. Reilly, muredach{at}mail.med.upenn.edu . Abstract OBJECTIVE Adipose inflammation plays a central role in obesity-related metabolic and cardiovascular complications. However, few human adipose-secreted proteins are known to mediate these processes. We hypothesized that microarray mRNA profiling of human adipose during evoked inflammation could identify novel adipocytokines. RESEARCH DESIGN AND METHODS Healthy human volunteers ( n = 14) were treated with intravenous endotoxin (3 ng/kg lipopolysaccharide [LPS]) and underwent subcutaneous adipose biopsies before and after LPS. On Affymetrix U133Plus 2.0 arrays, adipose mRNAs modulated >1.5-fold (with P < 0.00001) were selected. SignalP 3.0 and SecretomeP 2.0 identified genes predicted to encode secreted proteins. Of these, 86 candidates were chosen for validation in adipose from an independent human endotoxemia protocol ( N = 7, with 0.6 ng/kg LPS) and for exploration of cellular origin in primary human adipocytes and macrophages in vitro. RESULTS Microarray identified 776 adipose genes modulated by LPS; 298 were predicted to be secreted. Of detectable prioritized genes, 82 of 85 (96% [95% CI 90–99]) were upregulated (fold changes >1.0) during the lower-dose (LPS 0.6 ng/kg) validation study and 51 of 85 (59% [49–70]) were induced greater than 1.5-fold. Treatment of primary adipocytes with LPS and macrophage polarization to M1 proinflammatory phenotype increased expression by 1.5-fold for 58 and 73% of detectable genes, respectively. CONCLUSIONS We demonstrate that evoked inflammation of human adipose in vivo modulated expression of multiple genes likely secreted by adipocytes and monocytes. These included established adipocytokines and chemokines implicat