Thrombospondin-1 C-terminal-derived peptide protects thyroid cells from ceramide-induced apoptosis through the adenylyl cyclase pathway

Int J Biochem Cell Biol. 2006;38(12):2219-28. doi: 10.1016/j.biocel.2006.07.004. Epub 2006 Aug 12.

Abstract

Thrombospondin-1, a multi-modular matrix protein is able to interact with a variety of matrix proteins and cell-surface receptors. Thus it is multifunctional. In this work, we examined the role of thrombospondin-1 in ceramide-induced thyroid apoptosis. We focused on the VVM containing sequence localized in the C-terminal domain of the molecule. Primary cultured thyroid cells synthesize thrombospondin-1 depending on their morphological organization. As it leads thyrocytes to organize into monolayers before inducing apoptosis ceramide can modulate this organization. Here, we established that C(2)-ceramide treatment decreased thrombospondin-1 expression by interfering with the adenylyl cyclase pathway, thus leading to apoptosis. Furthermore, we demonstrated that the thrombospondin-1-derived peptide 4N1 (RFYVVMWK) abolished ceramide-induced thyroid cell death by preventing intracellular cAMP levels from dropping. Finally, we reported that 4N1-mediated inhibition of ceramide-induced apoptosis was consistently associated with a down-regulation of the caspase-3 processing. Integrin-associated protein receptor (IAP or CD47) was identified as a molecular relay mediating the observed 4N1 effects. Taken together, our results shed light for the first time on anti-apoptotic activities of the thrombospondin-1-derived peptide 4N1 and provide new information on how thrombospondin-1 may control apoptosis of non-tumoral cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylyl Cyclases / metabolism*
  • Animals
  • Apoptosis / drug effects*
  • Caspase 3 / metabolism
  • Cells, Cultured
  • Ceramides / pharmacology*
  • Cyclic AMP / metabolism
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Enzyme Activation / drug effects
  • Gene Expression Regulation / drug effects
  • Peptides / chemistry
  • Peptides / pharmacology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sphingosine / analogs & derivatives
  • Sphingosine / pharmacology
  • Swine
  • Thrombospondin 1 / chemistry*
  • Thyroid Gland / cytology
  • Thyroid Gland / drug effects*
  • Thyroid Gland / enzymology*
  • Thyroid Gland / pathology

Substances

  • Ceramides
  • N-acetylsphingosine
  • Peptides
  • RNA, Messenger
  • Thrombospondin 1
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • Caspase 3
  • Adenylyl Cyclases
  • Sphingosine