Impaired plasticity of macrophages in X-linked adrenoleukodystrophy

Brain. 2018 Aug 1;141(8):2329-2342. doi: 10.1093/brain/awy127.

Abstract

X-linked adrenoleukodystrophy is caused by ATP-binding cassette transporter D1 (ABCD1) mutations and manifests by default as slowly progressive spinal cord axonopathy with associated demyelination (adrenomyloneuropathy). In 60% of male cases, however, X-linked adrenoleukodystrophy converts to devastating cerebral inflammation and demyelination (cerebral adrenoleukodystrophy) with infiltrating blood-derived monocytes and macrophages and cytotoxic T cells that can only be stopped by allogeneic haematopoietic stem cell transplantation or gene therapy at an early stage of the disease. Recently, we identified monocytes/macrophages but not T cells to be severely affected metabolically by ABCD1 deficiency. Here we found by whole transcriptome analysis that, although monocytes of patients with X-linked adrenoleukodystrophy have normal capacity for macrophage differentiation and phagocytosis, they are pro-inflammatory skewed also in patients with adrenomyloneuropathy in the absence of cerebral inflammation. Following lipopolysaccharide activation, the ingestion of myelin debris, normally triggering anti-inflammatory polarization, did not fully reverse the pro-inflammatory status of X-linked adrenoleukodystrophy macrophages. Immunohistochemistry on post-mortem cerebral adrenoleukodystrophy lesions reflected the activation pattern by prominent presence of enlarged lipid-laden macrophages strongly positive for the pro-inflammatory marker co-stimulatory molecule CD86. Comparative analyses of lesions with matching macrophage density in cases of cerebral adrenoleukodystrophy and acute multiple sclerosis showed a similar extent of pro-inflammatory activation but a striking reduction of anti-inflammatory mannose receptor (CD206) and haemoglobin-haptoglobin receptor (CD163) expression on cerebral adrenoleukodystrophy macrophages. Accordingly, ABCD1-deficiency leads to an impaired plasticity of macrophages that is reflected in incomplete establishment of anti-inflammatory responses, thus possibly contributing to the devastating rapidly progressive demyelination in cerebral adrenoleukodystrophy that only in rare cases arrests spontaneously. These findings emphasize monocytes/macrophages as crucial therapeutic targets for preventing or stopping myelin destruction in patients with X-linked adrenoleukodystrophy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily D, Member 1 / genetics*
  • ATP Binding Cassette Transporter, Subfamily D, Member 1 / metabolism
  • ATP Binding Cassette Transporter, Subfamily D, Member 1 / physiology
  • ATP-Binding Cassette Transporters / genetics
  • Adrenoleukodystrophy / genetics
  • Adrenoleukodystrophy / immunology*
  • Adrenoleukodystrophy / physiopathology
  • Adult
  • Cell Plasticity / genetics
  • Cell Plasticity / physiology
  • Demyelinating Diseases / metabolism
  • European Continental Ancestry Group
  • Humans
  • Macrophages / metabolism*
  • Macrophages / physiology
  • Male
  • Middle Aged
  • Monocytes / metabolism
  • Monocytes / physiology
  • Myelin Sheath / metabolism
  • Whole Exome Sequencing / methods

Substances

  • ABCD1 protein, human
  • ATP Binding Cassette Transporter, Subfamily D, Member 1
  • ATP-Binding Cassette Transporters