Involvement of de novo ceramide synthesis in pro-inflammatory adipokine secretion and adipocyte-macrophage interaction

Yoji Hamada, Hiroshi Nagasaki, Atsushi Fujiya, Yusuke Seino, Qing Long Shang, Takeshi Suzuki, Hiroyuki Hashimoto, Yutaka Oiso

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Interaction between adipocytes and macrophages has been suggested to play a central role in the pathogenesis of obesity. Ceramide, a sphingolipid de novo synthesized from palmitate, is known to stimulate pro-inflammatory cytokine secretion from multiple types of cells. To clarify whether de novo synthesized ceramide contributes to cytokine dysregulation in adipocytes and macrophages, we observed cytokine secretion in mature 3T3-L1 adipocytes (L1) and RAW264.7 macrophages (RAW) cultured alone or co-cultured under the suppression of de novo ceramide synthesis.Palmitate enhanced ceramide accumulation and stimulated the expression and secretion of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) in L1. The suppression of serine-palmitoyl transferase, a rate-limiting enzyme of de novo ceramide synthesis, by myriocin or siRNA attenuated those palmitate-induced alterations, and a ceramide synthase inhibitor fumonisin B1 showed similar results. In contrast, the inhibitor of sphingosine kinase or a membrane-permeable ceramide analogue augmented the cytokine secretion. Myriocin effects on the palmitate-induced changes were not abrogated by toll-like receptor-4 blockade. Although palmitate stimulated RAW to secrete tumor necrosis factor-α (TNF-α), it did not significantly increase ceramide content, and neither myriocin nor fumonisin B1 attenuated the TNF-α hypersecretion. The co-culture of L1 with RAW markedly augmented IL-6 and MCP-1 levels in media. Myriocin or fumonisin B1 significantly lowered these cytokine levels and suppressed the gene expression of TNF-α and MCP-1 in RAW and of IL-6 and MCP-1 in L1.In conclusion, de novo synthesized ceramide partially mediates the palmitate effects on pro-inflammatory adipokines and is possibly involved in the interaction with macrophages.

Original languageEnglish
Pages (from-to)1309-1316
Number of pages8
JournalJournal of Nutritional Biochemistry
Volume25
Issue number12
DOIs
Publication statusPublished - 01-12-2014

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Molecular Biology
  • Nutrition and Dietetics
  • Clinical Biochemistry

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