Targeting myeloid cells to the brain using non-myeloablative conditioning

PLoS One. 2013 Nov 7;8(11):e80260. doi: 10.1371/journal.pone.0080260. eCollection 2013.

Abstract

Bone marrow-derived cells (BMDCs) are able to colonize the central nervous system (CNS) at sites of damage. This ability makes BMDCs an ideal cellular vehicle for transferring therapeutic genes/molecules to the CNS. However, conditioning is required for bone marrow-derived myeloid cells to engraft in the brain, which so far has been achieved by total body irradiation (TBI) and by chemotherapy (e.g. busulfan treatment). Unfortunately, both regimens massively disturb the host's hematopoietic compartment. Here, we established a conditioning protocol to target myeloid cells to sites of brain damage in mice using non-myeloablative focal head irradiation (HI). This treatment was associated with comparatively low inflammatory responses in the CNS despite cranial radiation doses which are identical to TBI, as revealed by gene expression analysis of cytokines/chemokines such as CCL2, CXCL10, TNF-α and CCL5. HI prior to bone marrow transplantation resulted in much lower levels of blood chimerism defined as the percentage of donor-derived cells in peripheral blood (< 5%) compared with TBI (> 95%) or busulfan treatment (> 50%). Nevertheless, HI effectively recruited myeloid cells to the area of motoneuron degeneration in the brainstem within 7 days after facial nerve axotomy. In contrast, no donor-derived cells were detected in the lesioned facial nucleus of busulfan-treated animals up to 2 weeks after transplantation. Our findings suggest that myeloid cells can be targeted to sites of brain damage even in the presence of very low levels of peripheral blood chimerism. We established a novel non-myeloablative conditioning protocol with minimal disturbance of the host's hematopoietic system for targeting BMDCs specifically to areas of pathology in the brain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Marrow Cells / cytology
  • Bone Marrow Cells / physiology
  • Bone Marrow Transplantation
  • Brain
  • Busulfan
  • Chemokine CCL2 / metabolism
  • Chemokine CCL5 / metabolism
  • Chemokine CXCL10 / metabolism
  • Hematopoietic System
  • Mice
  • Mice, Inbred C57BL
  • Myeloid Cells / cytology*
  • Myeloid Cells / physiology
  • Tumor Necrosis Factor-alpha / metabolism
  • Whole-Body Irradiation

Substances

  • Chemokine CCL2
  • Chemokine CCL5
  • Chemokine CXCL10
  • Tumor Necrosis Factor-alpha
  • Busulfan

Grants and funding

This work was supported by Deutsche Forschungsgemeinschaft grants FOR 1336 and TRR43. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.