Gene profiling of human adipose tissue during evoked inflammation in vivo.
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.


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 implicated in recruitment and activation of lymphocytes, adhesion molecules, antioxidants, and several novel genes with unknown function. Such candidates may represent biomarkers and therapeutic targets for obesity-related complications.
Shah
Rachana
R
Division of Pediatric Endocrinology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Lu
Yun
Y
Hinkle
Christine C
CC
McGillicuddy
Fiona C
FC
Kim
Roy
R
Hannenhalli
Sridhar
S
Cappola
Thomas P
TP
Heffron
Sean
S
Wang
XingMei
X
Mehta
Nehal N
NN
Putt
Mary
M
Reilly
Muredach P
MP
D017667:Adipocytes / Q000187:drug effects / Q000502:physiology; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000139:chemically induced / Q000235:genetics*; D008070:Lipopolysaccharides / Q000633:toxicity*; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics; D012016:Reference Values
D008070:Lipopolysaccharides; D012333:RNA, Messenger