Hematopoietic cells maintain hematopoietic fates upon entering the brain - PubMed (original) (raw)

Hematopoietic cells maintain hematopoietic fates upon entering the brain

Mei Massengale et al. J Exp Med. 2005.

Abstract

Several studies have reported that bone marrow (BM) cells may give rise to neurons and astrocytes in vitro and in vivo. To further test this hypothesis, we analyzed for incorporation of neural cell types expressing donor markers in normal or injured brains of irradiated mice reconstituted with whole BM or single, purified c-kit(+)Thy1.1(lo)Lin(-)Sca-1(+) (KTLS) hematopoietic stem cells (HSCs), and of unirradiated parabionts with surgically anastomosed vasculature. Each model showed low-level parenchymal engraftment of donor-marker(+) cells with 96-100% immunoreactivity for panhematopoietic (CD45) or microglial (Iba1 or Mac1) lineage markers in all cases studied. Other than one arborizing structure in the olfactory bulb of one BM-transplanted animal, possibly representing a neuronal or glial cell process, we found no donor-marker-expressing astrocytes or non-Purkinje neurons among >10,000 donor-marker(+) cells from 21 animals. These data strongly suggest that HSCs and their progeny maintain lineage fidelity in the brain and do not adopt neural cell fates with any measurable frequency.

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Figures

Figure 1.

Figure 1.

Confocal micrographs depicting microgliosis in the injured hippocampus of irradiated recipient mice, killed 8 d after KA injection, and 4.5 mo after transplantation with a single GFP+ HSC. Tissue sections were costained with Hoechst 33342, anti–Iba-1 and anti-GFP antibodies. Images represent 10× (A–C) or 40× oil (D–F) magnification. Fluorescence shown is as follows: A and D: Hoechst 33342 (blue) and Iba-1 (red); B and E: Hoechst 33342 (blue) and GFP (green); C and F: Iba-1 (red) and GFP. Bar: A–C, 100 μm; D–F, 20 μm.

Figure 2.

Figure 2.

Laser scanning confocal images of microglia from brain tissue of a single HSC transplanted mouse killed at day 8 after KA injection (A–H) or a single HSC transplanted mouse transplanted and killed without additional brain injury (I–L). Tissues were stained with anti–Mac-1 or anti–Iba-1 antibodies (red); anti-GFP antibody (green); and Hoechst 33342 (blue). Fluorescence shown is as follows: GFP (B, F, and J); Hoechst 3342 (C, G, and K); Mac-1 (D and H); Iba-1 (L); merged (A, E, and I). Bar, 10 μm.

Figure 3.

Figure 3.

Representative laser scanning confocal micrographs of mouse brain cells negative for CD45 and microglial markers (Mac-1 or Iba-1). Animals were transplanted with single HSC (A–C) or whole BM (D–O). Tissues were stained with anti-CD45 and anti–Iba-1 (A–C and G–I, red) or anti-CD45 and anti–Mac-1 (D–F and J-O, red); anti-GFP (green); and Hoechst 33342 (blue). For A–C, CD45 and Iba-1 were detected using Alexa633 and Alexa594 dyes, respectively (C, merged image). Bar, 10 μm.

Figure 4.

Figure 4.

Laser scanning confocal micrographs of sections of brain tissue from mice transplanted with whole BM as newborns (A–J and S–V) or as adults (K–R). Tissue sections were stained with Hoechst 33342 (blue), anti-NeuN antibody (red), and anti-CD45 antibody (purple) and visualized at 63× oil (all images except D, E, I, and J) and 100× oil (D, E, I, and J). Apparent NeuN staining visualized under 63× oil objective (C and H) was found to weaken (D) or persist as faint positive NeuN staining (I) when viewed under the 100× objective (see Discussion). Images shown in A–E and S–V are taken from periventricular regions; in F–J, images are taken from the hippocampus; in K–N, images are taken from a location that included leptomeninges; and in O–R, images are taken from the olfactory bulb. Bar, 10 μm.

Figure 5.

Figure 5.

Laser scanning confocal micrographs showing donor marker expression in an arborizing structure consistent with an apparent cell process in the olfactory bulb of a whole BM–transplanted mouse (transplanted at birth). Tissues were stained for anti-GFP antibody (A–C, green); Hoechst 33342 (B and D, blue), and either anti-NeuN (C) or anti-GFAP antibodies (F). The green signal in D–F represents native fluorescence of GFP without amplification. Images in A–C and D–F are separated by 32 μm of tissue. Bar, 10 μm.

Figure 6.

Figure 6.

Laser scanning confocal micrographs showing a GFP+ Purkinje cell. Tissues were stained with anti-Calbindin antibody (A, red) and Hoechst 33342 (A, blue). GFP signal (A and B, green) is endogenous and unamplified.

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References

    1. Brazelton, T.R., F.M. Rossi, G.I. Keshet, and H.M. Blau. 2000. From marrow to brain: expression of neuronal phenotypes in adult mice. Science. 290:1775–1779. - PubMed
    1. Mezey, E., K.J. Chandross, G. Harta, R.A. Maki, and S.R. McKercher. 2000. Turning blood into brain: cells bearing neuronal antigens generated in vivo from bone marrow. Science. 290:1779–1782. - PubMed
    1. Black, I.B., and D. Woodbury. 2001. Adult rat and human bone marrow stromal stem cells differentiate into neurons. Blood Cells Mol. Dis. 27:632–636. - PubMed
    1. Cogle, C.R., A.T. Yachnis, E.D. Laywell, D.S. Zander, J.R. Wingard, D.A. Steindler, and E.W. Scott. 2004. Bone marrow transdifferentiation in brain after transplantation: a retrospective study. Lancet. 363:1432–1437. - PubMed
    1. Kabos, P., M. Ehtesham, A. Kabosova, K.L. Black, and J.S. Yu. 2002. Generation of neural progenitor cells from whole adult bone marrow. Exp. Neurol. 178:288–293. - PubMed

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