Glucocorticoid reamplification within cells intensifies NF-kappaB and MAPK signaling and reinforces inflammation in activated preadipocytes.
Increased expression and activity of the intracellular glucocorticoid-reactivating enzyme 11 beta-hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) contribute to dysfunction of adipose tissue. Although the pathophysiological role of 11 beta-HSD1 in mature adipocytes has long been investigated, its potential role in preadipocytes still remains obscure. The present study demonstrates that the expression of 11 beta-HSD1 in preadipocyte-rich stromal vascular fraction (SVF) cells in fat depots from ob/ob and diet-induced obese mice was markedly elevated compared with lean control. In 3T3-L1 preadipocytes, the level of mRNA and reductase activity of 11 beta-HSD1 was augmented by TNF-alpha, IL-1 beta, and LPS, with a concomitant increase in inducible nitric oxide synthase (iNOS), monocyte chemoattractant protein-1 (MCP-1), or IL-6 secretion. Pharmacological inhibition of 11 beta-HSD1 and RNA interference against 11 beta-HSD1 reduced the mRNA and protein levels of iNOS, MCP-1, and IL-6. In contrast, overexpression of 11 beta-HSD1 further augmented TNF-alpha-induced iNOS, IL-6, and MCP-1 expression. Moreover, 11 beta-HSD1 inhibitors attenuated TNF-alpha-induced phosphorylation of NF-kappaB p65 and p38-, JNK-, and ERK1/2-MAPK. Collectively, the present study provides novel evidence that inflammatory stimuli-induced 11 beta-HSD1 in activated preadipocytes intensifies NF-kappaB and MAPK signaling pathways and results in further induction of proinflammatory molecules. Not limited to 3T3-L1 preadipocytes, we also demonstrated that the notion was reproducible in the primary SVF cells from obese mice. These findings highlight an unexpected, proinflammatory role of reamplified glucocorticoids within preadipocytes in obese adipose tissue.
Division of Endocrinology and Metabolism, Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54, Shogoin Kawaharacho, Sakyoku, Kyoto, 606-8507, Japan.
Takako
T
Ishii-Yonemoto
Hiroaki
H
Masuzaki
Shintaro
S
Yasue
Sadanori
S
Okada
Chisayo
C
Kozuka
Tomohiro
T
Tanaka
Michio
M
Noguchi
Tsutomu
T
Tomita
Junji
J
Fujikura
Yuji
Y
Yamamoto
Ken
K
Ebihara
Kiminori
K
Hosoda
Kazuwa
K
Nakao
D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000235:genetics / Q000378:metabolism*; D017667:Adipocytes / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D015971:Gene Expression Regulation, Enzymologic; D005938:Glucocorticoids / Q000235:genetics* / Q000378:metabolism; D007249:Inflammation / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009765:Obesity / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016207:Cytokines; D005938:Glucocorticoids; D016328:NF-kappa B; D012333:RNA, Messenger; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D020928:Mitogen-Activated Protein Kinases