LYVE-1–Positive Macrophages Are Present in Normal Murine Eyes

Heping Xu, Mei Chen, Delyth Marion Reid, John Vincent Forrester

Research output: Contribution to journalArticle

65 Citations (Scopus)

Abstract

PURPOSE. A functioning lymphatic system is necessary not only to permit the organism to mount a rapid and effective immune response but, even more so, to maintain tissue fluid homeostasis. However, no clear evidence of lymphatic vessels draining intraocular and orbital tissues-retina, choroid, sclera, and extraocular muscles-exists.

METHODS. Ocular tissue flatmounts from normal or enhanced green fluorescence protein (EGFP) chimeric mice were immunostained for lymphatic endothelium hyaluronan receptor (LYVE-1, a routinely used lymphatic endothelial marker), podoplanin, Flt4/VEGFR3, Sca-1, CD11b, or F4/80 and were observed by confocal microscopy. Single-cell suspensions from ocular tissues were also prepared and were analyzed by flow cytometry.

RESULTS. Lymphatic vessels were detected in the posterior regions of the extraocular muscles and the connective tissues of the extraocular muscle cones in the normal mouse. No typical lymphatic vessels were found within the eye. A large population of LYVE-1(+) nonendothelial cells, distributed as single cells, was detected in all ocular tissues except the central cornea. These cells also express another lymphatic endothelial cell marker, Flt4/VEGFR3, but not podoplanin, and they have hyaluronan-binding ability. Bone marrow chimerism studies indicated that the LYVE-1(+) cell populations are bone marrow derived and have a slow turnover in ocular tissues (3-6 months). Phenotype analysis revealed that nonendothelial LYVE-1(+) cells in the sclera, choroid, and iris included CD11b(+)F4/80(+) macrophages, CD11b(+)F4/80(-) macrophages and CD11b(-)F4/80(-) bone marrow-derived cells. All LYVE-I cells in the retina were CD11b(+)F4/80(+) macrophages. Cells in the limbus and the iris root also express Sca-1, suggesting that they are hematopoietic lymphatic vessel progenitor cells.

CONCLUSIONS. These observations suggest that a lymphatic system exists for the transport of immune cells and fluids from the posterior segment of the eye, that ocular tissues are rich in bone marrow-derived LYVE-1(+) macrophages under normal physiological conditions, and that a subpopulation of these cells may represent resident precursor cells necessary for the de novo formation of ocular/orbital lymphatic vessels in pathologic conditions.

Original languageEnglish
Pages (from-to)2162-2171
Number of pages10
JournalInvestigative Ophthalmology & Visual Science
Volume48
Issue number5
DOIs
Publication statusPublished - May 2007

Keywords

  • hyaluronan receptor LYVE-1
  • lymphatic-endothelium
  • aqueous humour
  • in-vivo
  • anterior-chamber
  • growth-factor
  • uveal tract
  • lymphangiogenesis
  • drainage
  • hemangiogenesis

Cite this

LYVE-1–Positive Macrophages Are Present in Normal Murine Eyes. / Xu, Heping; Chen, Mei; Reid, Delyth Marion; Forrester, John Vincent.

In: Investigative Ophthalmology & Visual Science, Vol. 48, No. 5, 05.2007, p. 2162-2171.

Research output: Contribution to journalArticle

Xu, Heping ; Chen, Mei ; Reid, Delyth Marion ; Forrester, John Vincent. / LYVE-1–Positive Macrophages Are Present in Normal Murine Eyes. In: Investigative Ophthalmology & Visual Science. 2007 ; Vol. 48, No. 5. pp. 2162-2171.
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abstract = "PURPOSE. A functioning lymphatic system is necessary not only to permit the organism to mount a rapid and effective immune response but, even more so, to maintain tissue fluid homeostasis. However, no clear evidence of lymphatic vessels draining intraocular and orbital tissues-retina, choroid, sclera, and extraocular muscles-exists.METHODS. Ocular tissue flatmounts from normal or enhanced green fluorescence protein (EGFP) chimeric mice were immunostained for lymphatic endothelium hyaluronan receptor (LYVE-1, a routinely used lymphatic endothelial marker), podoplanin, Flt4/VEGFR3, Sca-1, CD11b, or F4/80 and were observed by confocal microscopy. Single-cell suspensions from ocular tissues were also prepared and were analyzed by flow cytometry.RESULTS. Lymphatic vessels were detected in the posterior regions of the extraocular muscles and the connective tissues of the extraocular muscle cones in the normal mouse. No typical lymphatic vessels were found within the eye. A large population of LYVE-1(+) nonendothelial cells, distributed as single cells, was detected in all ocular tissues except the central cornea. These cells also express another lymphatic endothelial cell marker, Flt4/VEGFR3, but not podoplanin, and they have hyaluronan-binding ability. Bone marrow chimerism studies indicated that the LYVE-1(+) cell populations are bone marrow derived and have a slow turnover in ocular tissues (3-6 months). Phenotype analysis revealed that nonendothelial LYVE-1(+) cells in the sclera, choroid, and iris included CD11b(+)F4/80(+) macrophages, CD11b(+)F4/80(-) macrophages and CD11b(-)F4/80(-) bone marrow-derived cells. All LYVE-I cells in the retina were CD11b(+)F4/80(+) macrophages. Cells in the limbus and the iris root also express Sca-1, suggesting that they are hematopoietic lymphatic vessel progenitor cells.CONCLUSIONS. These observations suggest that a lymphatic system exists for the transport of immune cells and fluids from the posterior segment of the eye, that ocular tissues are rich in bone marrow-derived LYVE-1(+) macrophages under normal physiological conditions, and that a subpopulation of these cells may represent resident precursor cells necessary for the de novo formation of ocular/orbital lymphatic vessels in pathologic conditions.",
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T1 - LYVE-1–Positive Macrophages Are Present in Normal Murine Eyes

AU - Xu, Heping

AU - Chen, Mei

AU - Reid, Delyth Marion

AU - Forrester, John Vincent

PY - 2007/5

Y1 - 2007/5

N2 - PURPOSE. A functioning lymphatic system is necessary not only to permit the organism to mount a rapid and effective immune response but, even more so, to maintain tissue fluid homeostasis. However, no clear evidence of lymphatic vessels draining intraocular and orbital tissues-retina, choroid, sclera, and extraocular muscles-exists.METHODS. Ocular tissue flatmounts from normal or enhanced green fluorescence protein (EGFP) chimeric mice were immunostained for lymphatic endothelium hyaluronan receptor (LYVE-1, a routinely used lymphatic endothelial marker), podoplanin, Flt4/VEGFR3, Sca-1, CD11b, or F4/80 and were observed by confocal microscopy. Single-cell suspensions from ocular tissues were also prepared and were analyzed by flow cytometry.RESULTS. Lymphatic vessels were detected in the posterior regions of the extraocular muscles and the connective tissues of the extraocular muscle cones in the normal mouse. No typical lymphatic vessels were found within the eye. A large population of LYVE-1(+) nonendothelial cells, distributed as single cells, was detected in all ocular tissues except the central cornea. These cells also express another lymphatic endothelial cell marker, Flt4/VEGFR3, but not podoplanin, and they have hyaluronan-binding ability. Bone marrow chimerism studies indicated that the LYVE-1(+) cell populations are bone marrow derived and have a slow turnover in ocular tissues (3-6 months). Phenotype analysis revealed that nonendothelial LYVE-1(+) cells in the sclera, choroid, and iris included CD11b(+)F4/80(+) macrophages, CD11b(+)F4/80(-) macrophages and CD11b(-)F4/80(-) bone marrow-derived cells. All LYVE-I cells in the retina were CD11b(+)F4/80(+) macrophages. Cells in the limbus and the iris root also express Sca-1, suggesting that they are hematopoietic lymphatic vessel progenitor cells.CONCLUSIONS. These observations suggest that a lymphatic system exists for the transport of immune cells and fluids from the posterior segment of the eye, that ocular tissues are rich in bone marrow-derived LYVE-1(+) macrophages under normal physiological conditions, and that a subpopulation of these cells may represent resident precursor cells necessary for the de novo formation of ocular/orbital lymphatic vessels in pathologic conditions.

AB - PURPOSE. A functioning lymphatic system is necessary not only to permit the organism to mount a rapid and effective immune response but, even more so, to maintain tissue fluid homeostasis. However, no clear evidence of lymphatic vessels draining intraocular and orbital tissues-retina, choroid, sclera, and extraocular muscles-exists.METHODS. Ocular tissue flatmounts from normal or enhanced green fluorescence protein (EGFP) chimeric mice were immunostained for lymphatic endothelium hyaluronan receptor (LYVE-1, a routinely used lymphatic endothelial marker), podoplanin, Flt4/VEGFR3, Sca-1, CD11b, or F4/80 and were observed by confocal microscopy. Single-cell suspensions from ocular tissues were also prepared and were analyzed by flow cytometry.RESULTS. Lymphatic vessels were detected in the posterior regions of the extraocular muscles and the connective tissues of the extraocular muscle cones in the normal mouse. No typical lymphatic vessels were found within the eye. A large population of LYVE-1(+) nonendothelial cells, distributed as single cells, was detected in all ocular tissues except the central cornea. These cells also express another lymphatic endothelial cell marker, Flt4/VEGFR3, but not podoplanin, and they have hyaluronan-binding ability. Bone marrow chimerism studies indicated that the LYVE-1(+) cell populations are bone marrow derived and have a slow turnover in ocular tissues (3-6 months). Phenotype analysis revealed that nonendothelial LYVE-1(+) cells in the sclera, choroid, and iris included CD11b(+)F4/80(+) macrophages, CD11b(+)F4/80(-) macrophages and CD11b(-)F4/80(-) bone marrow-derived cells. All LYVE-I cells in the retina were CD11b(+)F4/80(+) macrophages. Cells in the limbus and the iris root also express Sca-1, suggesting that they are hematopoietic lymphatic vessel progenitor cells.CONCLUSIONS. These observations suggest that a lymphatic system exists for the transport of immune cells and fluids from the posterior segment of the eye, that ocular tissues are rich in bone marrow-derived LYVE-1(+) macrophages under normal physiological conditions, and that a subpopulation of these cells may represent resident precursor cells necessary for the de novo formation of ocular/orbital lymphatic vessels in pathologic conditions.

KW - hyaluronan receptor LYVE-1

KW - lymphatic-endothelium

KW - aqueous humour

KW - in-vivo

KW - anterior-chamber

KW - growth-factor

KW - uveal tract

KW - lymphangiogenesis

KW - drainage

KW - hemangiogenesis

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DO - 10.1167/iovs.06-0783

M3 - Article

VL - 48

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JO - Investigative Ophthalmology & Visual Science

JF - Investigative Ophthalmology & Visual Science

SN - 0146-0404

IS - 5

ER -