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Opposing roles for membrane bound and soluble Fas ligand in glaucoma-associated retinal ganglion cell death.

Gregory MS, Hackett CG, Abernathy EF, Lee KS, Saff RR, Hohlbaum AM, Moody KS, Hobson MW, Jones A, Kolovou P, Karray S, Giani A, John SW, Chen DF, Marshak-Rothstein A, Ksander BR - PLoS ONE (2011)

Bottom Line: Previous studies documented that constitutive ocular expression of FasL maintained immune privilege and prevented neoangeogenesis.We now show that FasL also plays a major role in retinal neurotoxicity.By contrast, FasL-deficiency, or administration of soluble FasL, protected RGCs from cell death.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, The Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Glaucoma, the most frequent optic neuropathy, is a leading cause of blindness worldwide. Death of retinal ganglion cells (RGCs) occurs in all forms of glaucoma and accounts for the loss of vision, however the molecular mechanisms that cause RGC loss remain unclear. The pro-apoptotic molecule, Fas ligand, is a transmembrane protein that can be cleaved from the cell surface by metalloproteinases to release a soluble protein with antagonistic activity. Previous studies documented that constitutive ocular expression of FasL maintained immune privilege and prevented neoangeogenesis. We now show that FasL also plays a major role in retinal neurotoxicity. Importantly, in both TNFα triggered RGC death and a spontaneous model of glaucoma, gene-targeted mice that express only full-length FasL exhibit accelerated RGC death. By contrast, FasL-deficiency, or administration of soluble FasL, protected RGCs from cell death. These data identify membrane-bound FasL as a critical effector molecule and potential therapeutic target in glaucoma.

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Expression of Fas and FasL in the neural retina of WT and ΔCS mice.Frozen retinal sections were prepared from WT and ΔCS mice that were either (i) untreated, or (ii) received a prior (7 days) intravitreal injection of TNFα. (A) Fas receptor expression using an anti Fas antibody (Red) and TOPRO (blue nuclear stain). (B) FasL expression using an anti FasL antibody (red) and TOPRO (blue nuclear stain). Identically treated retinal sections from FasL KO mice were used as a negative control. (C) Double staining for microglia (Iba1-green) and FasL (red) revealed retinal microglia (arrowhead) express FasL. (D) Double staining for astrocytes (GFAP-red) and FasL (green) revealed retinal astrocytes (arrowhead) were FasL negative. (E) Representative TUNEL staining in ΔCS mice at 24 hours post TNFα injection. Red = TUNEL, Blue = nuclear stain. GCL- ganglion cell layer; INL- inner nuclear layer; ONL- outer nuclear layer. (F) Percentages of TUNEL positive cells in the retina. (N = 5 per group). (* p>0.05). See also Figure S2.
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pone-0017659-g005: Expression of Fas and FasL in the neural retina of WT and ΔCS mice.Frozen retinal sections were prepared from WT and ΔCS mice that were either (i) untreated, or (ii) received a prior (7 days) intravitreal injection of TNFα. (A) Fas receptor expression using an anti Fas antibody (Red) and TOPRO (blue nuclear stain). (B) FasL expression using an anti FasL antibody (red) and TOPRO (blue nuclear stain). Identically treated retinal sections from FasL KO mice were used as a negative control. (C) Double staining for microglia (Iba1-green) and FasL (red) revealed retinal microglia (arrowhead) express FasL. (D) Double staining for astrocytes (GFAP-red) and FasL (green) revealed retinal astrocytes (arrowhead) were FasL negative. (E) Representative TUNEL staining in ΔCS mice at 24 hours post TNFα injection. Red = TUNEL, Blue = nuclear stain. GCL- ganglion cell layer; INL- inner nuclear layer; ONL- outer nuclear layer. (F) Percentages of TUNEL positive cells in the retina. (N = 5 per group). (* p>0.05). See also Figure S2.

Mentions: Retinal tissue from TNFα treated WT and ΔCS mice were examined by immuno-histochemical staining for Fas and FasL to confirm that Fas+ target cells were present within the ganglion cell layer and to determine which cell types were potential FasL effector cells. As expected, Fas was highly expressed in the ganglion cell layer and the level of Fas was similar in TNFα treated WT and ΔCS mice (Figure 5A).


Opposing roles for membrane bound and soluble Fas ligand in glaucoma-associated retinal ganglion cell death.

Gregory MS, Hackett CG, Abernathy EF, Lee KS, Saff RR, Hohlbaum AM, Moody KS, Hobson MW, Jones A, Kolovou P, Karray S, Giani A, John SW, Chen DF, Marshak-Rothstein A, Ksander BR - PLoS ONE (2011)

Expression of Fas and FasL in the neural retina of WT and ΔCS mice.Frozen retinal sections were prepared from WT and ΔCS mice that were either (i) untreated, or (ii) received a prior (7 days) intravitreal injection of TNFα. (A) Fas receptor expression using an anti Fas antibody (Red) and TOPRO (blue nuclear stain). (B) FasL expression using an anti FasL antibody (red) and TOPRO (blue nuclear stain). Identically treated retinal sections from FasL KO mice were used as a negative control. (C) Double staining for microglia (Iba1-green) and FasL (red) revealed retinal microglia (arrowhead) express FasL. (D) Double staining for astrocytes (GFAP-red) and FasL (green) revealed retinal astrocytes (arrowhead) were FasL negative. (E) Representative TUNEL staining in ΔCS mice at 24 hours post TNFα injection. Red = TUNEL, Blue = nuclear stain. GCL- ganglion cell layer; INL- inner nuclear layer; ONL- outer nuclear layer. (F) Percentages of TUNEL positive cells in the retina. (N = 5 per group). (* p>0.05). See also Figure S2.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3066205&req=5

pone-0017659-g005: Expression of Fas and FasL in the neural retina of WT and ΔCS mice.Frozen retinal sections were prepared from WT and ΔCS mice that were either (i) untreated, or (ii) received a prior (7 days) intravitreal injection of TNFα. (A) Fas receptor expression using an anti Fas antibody (Red) and TOPRO (blue nuclear stain). (B) FasL expression using an anti FasL antibody (red) and TOPRO (blue nuclear stain). Identically treated retinal sections from FasL KO mice were used as a negative control. (C) Double staining for microglia (Iba1-green) and FasL (red) revealed retinal microglia (arrowhead) express FasL. (D) Double staining for astrocytes (GFAP-red) and FasL (green) revealed retinal astrocytes (arrowhead) were FasL negative. (E) Representative TUNEL staining in ΔCS mice at 24 hours post TNFα injection. Red = TUNEL, Blue = nuclear stain. GCL- ganglion cell layer; INL- inner nuclear layer; ONL- outer nuclear layer. (F) Percentages of TUNEL positive cells in the retina. (N = 5 per group). (* p>0.05). See also Figure S2.
Mentions: Retinal tissue from TNFα treated WT and ΔCS mice were examined by immuno-histochemical staining for Fas and FasL to confirm that Fas+ target cells were present within the ganglion cell layer and to determine which cell types were potential FasL effector cells. As expected, Fas was highly expressed in the ganglion cell layer and the level of Fas was similar in TNFα treated WT and ΔCS mice (Figure 5A).

Bottom Line: Previous studies documented that constitutive ocular expression of FasL maintained immune privilege and prevented neoangeogenesis.We now show that FasL also plays a major role in retinal neurotoxicity.By contrast, FasL-deficiency, or administration of soluble FasL, protected RGCs from cell death.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, The Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts, United States of America.

ABSTRACT
Glaucoma, the most frequent optic neuropathy, is a leading cause of blindness worldwide. Death of retinal ganglion cells (RGCs) occurs in all forms of glaucoma and accounts for the loss of vision, however the molecular mechanisms that cause RGC loss remain unclear. The pro-apoptotic molecule, Fas ligand, is a transmembrane protein that can be cleaved from the cell surface by metalloproteinases to release a soluble protein with antagonistic activity. Previous studies documented that constitutive ocular expression of FasL maintained immune privilege and prevented neoangeogenesis. We now show that FasL also plays a major role in retinal neurotoxicity. Importantly, in both TNFα triggered RGC death and a spontaneous model of glaucoma, gene-targeted mice that express only full-length FasL exhibit accelerated RGC death. By contrast, FasL-deficiency, or administration of soluble FasL, protected RGCs from cell death. These data identify membrane-bound FasL as a critical effector molecule and potential therapeutic target in glaucoma.

Show MeSH
Related in: MedlinePlus