TREM2-Transduced Myeloid Precursors Mediate Nervous Tissue Debris Clearance and Facilitate Recovery in an Animal Model of Multiple Sclerosis (original) (raw)
Figure 4
Migration of TREM2-Transduced Myeloid Cells into EAE Lesions
(A) Detection of invaded myeloid cells in the spinal cord of EAE-diseased mice. Histological sections were obtained at day 2 after intravenous injection of GFP-transduced cells in EAE-diseased mice. Myeloid cells were injected at day 4 after first clinical signs of EAE. Sections were labeled with CD45-specific antibodies. Injected myeloid cells expressed CD45 and accumulated in inflammatory lesions. Scale bar indicates 50 μm.
(B) No Iba1 antigen was detected on invaded myeloid cells by double immunofluorescence labeling. GFP+ cells were analyzed in the spinal cord of EAE-diseased mice 4 d after intravenous injection of GFP-transduced myeloid cells. Myeloid cells were applied 4 d after first clinical signs of the disease. Invaded cells showed round appearance, reminiscent of activated macrophage/microglial cells. Scale bar indicates 10 μm.
(C) Quantification of cells invaded into the spinal cord of EAE-diseased mice. TREM2-transduced BM-MC or GFP-transduced BM-MC were injected intravenously at day 4 after the first clinical signs of the disease appeared. The BM-MCs migrated into spinal cord lesions within 2 h after intravenous application and remained there for 2–4 d. No GFP+ cells were detected within the spinal cord at day 7 after intravenous application. Data are presented as mean ± SEM.
(D) Flow cytometry analysis of TREM2 expression on TREM2-transduced and GFP-transduced myeloid cells obtained from the spinal cord of EAE-diseased mice at day 2 after application. Expression of TREM2 was detected on myeloid cells transduced with TREM2 (red tracing), but not on cells transduced with GFP (green tracing). Tracings shown are from cells gated for GFP. Control antibody isotype is shown as grey-filled tracing.
(E) Flow cytometry analysis of CD45 expression on GFP-transduced myeloid cells before injection (green tracing) and on GFP+ cells invaded into the spinal cord (red tracing) at day 4 after injection. Engrafted myeloid cells showed reduced levels of CD45 expression, reminiscent of microglia. Tracings shown are from cells gated for GFP. Control antibody isotype is shown as grey-filled tracing.