Fingolimod attenuates ceramide-induced blood-brain barrier dysfunction in multiple sclerosis by targeting reactive astrocytes

Acta Neuropathol. 2012 Sep;124(3):397-410. doi: 10.1007/s00401-012-1014-4. Epub 2012 Jul 19.

Abstract

Alterations in sphingolipid metabolism are described to contribute to various neurological disorders. We here determined the expression of enzymes involved in the sphingomyelin cycle and their products in postmortem brain tissue of multiple sclerosis (MS) patients. In parallel, we investigated the effect of the sphingosine-1 receptor agonist Fingolimod (Gilenya(®)) on sphingomyelin metabolism in reactive astrocytes and determined its functional consequences for the process of neuro-inflammation. Our results demonstrate that in active MS lesions, marked by large number of infiltrated immune cells, an altered expression of enzymes involved in the sphingomyelin cycle favors enhanced ceramide production. We identified reactive astrocytes as the primary cellular source of enhanced ceramide production in MS brain samples. Astrocytes isolated from MS lesions expressed enhanced mRNA levels of the ceramide-producing enzyme acid sphingomyelinase (ASM) compared to astrocytes isolated from control white matter. In addition, TNF-α treatment induced ASM mRNA and ceramide levels in astrocytes isolated from control white matter. Incubation of astrocytes with Fingolimod prior to TNF-α treatment reduced ceramide production and mRNA expression of ASM to control levels in astrocytes. Importantly, supernatants derived from reactive astrocytes treated with Fingolimod significantly reduced transendothelial monocyte migration. Overall, the present study demonstrates that reactive astrocytes represent a possible additional cellular target for Fingolimod in MS by directly reducing the production of pro-inflammatory lipids and limiting subsequent transendothelial leukocyte migration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Astrocytes / drug effects*
  • Astrocytes / metabolism
  • Astrocytes / pathology
  • Blood-Brain Barrier / drug effects*
  • Blood-Brain Barrier / pathology
  • Blood-Brain Barrier / physiopathology
  • Cell Movement / drug effects
  • Cells, Cultured
  • Ceramides / metabolism*
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Endothelial Cells / pathology
  • Female
  • Fingolimod Hydrochloride
  • Humans
  • Immunosuppressive Agents / pharmacology*
  • Male
  • Middle Aged
  • Monocytes / drug effects
  • Monocytes / metabolism
  • Monocytes / pathology
  • Multiple Sclerosis / metabolism
  • Multiple Sclerosis / pathology
  • Multiple Sclerosis / physiopathology*
  • Propylene Glycols / pharmacology*
  • Sphingomyelins / metabolism
  • Sphingosine / analogs & derivatives*
  • Sphingosine / pharmacology

Substances

  • Ceramides
  • Immunosuppressive Agents
  • Propylene Glycols
  • Sphingomyelins
  • Fingolimod Hydrochloride
  • Sphingosine