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Vps35 haploinsufficiency results in degenerative-like deficit in mouse retinal ganglion neurons and impairment of optic nerve injury-induced gliosis.

Liu W, Tang FL, Erion J, Xiao H, Ye J, Xiong WC - Mol Brain (2014)

Bottom Line: VPS35 (vacuolar protein sorting 35) is a major component of retromer that selectively promotes endosome-to-Golgi retrieval of transmembrane proteins.RGCs from young adult Vps35 heterozygotes (Vps35+/m) show degenerative-like features, such as dystrophic dendrites, reduced axon fibers, and increased TUNEL labeled RGCs.Additionally, gliosis in the optic nerve is transiently elevated in neonatal, but reduced in aged Vps35+/m mice.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China. yejian1979@163.com.

ABSTRACT
VPS35 (vacuolar protein sorting 35) is a major component of retromer that selectively promotes endosome-to-Golgi retrieval of transmembrane proteins. Dysfunction of retromer is a risk factor for the pathogenesis of Parkinson's disease (PD) and Alzheimer's disease (AD), both neuro-degeneration disorders. However, VPS35/retromer's function in retina or the contribution of Vps35-deficiency to retinal neuro-degenerative disorders has not been investigated. Here we provide evidence for a role of VPS35 in mouse retinal ganglion cell (RGC) survival and regeneration. VPS35 is selectively expressed in developing mouse RGCs. RGCs from young adult Vps35 heterozygotes (Vps35+/m) show degenerative-like features, such as dystrophic dendrites, reduced axon fibers, and increased TUNEL labeled RGCs. Additionally, gliosis in the optic nerve is transiently elevated in neonatal, but reduced in aged Vps35+/m mice. Optic nerve injury-induced gliosis is also attenuated in Vps35+/m mice. These results suggest that Vps35 is necessary for mouse RGC survival and regeneration, and Vps35-deficiency may contribute to the pathogenesis of retinal ganglion neuro-degeneration, a critical pathology leading to the blindness of many retinal degenerative disorders.

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Vps35 expression in developing mouse retinas. (A) X-gal staining (Blue color) showed lacZ gene expression in the retina of vps35+/m mice at indicated ages. Scale bar, 200 μm. (B) The high magnification of X-gal staining images was shown. GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL: outer plexiform layer; ONL: outer nuclear layer; OS: outer segment; IS, inner segment. Scale bar, 50 μm. In addition to GCL, a few LacZ positive cells were detected in INL indicated by arrow heads. (C) Western blot analysis of VPS35 expression in retina homogenates from vps35+/+ and +/m at indicated ages. (D) Quantification analysis of percentage of LacZ positive cells. (E) Quantification analysis of VPS35 protein levels in retina from indicated age-groups of vps35+/+ and +/m mice. In (D-E), mean+/-SEM (n = 5) were presented.
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Figure 1: Vps35 expression in developing mouse retinas. (A) X-gal staining (Blue color) showed lacZ gene expression in the retina of vps35+/m mice at indicated ages. Scale bar, 200 μm. (B) The high magnification of X-gal staining images was shown. GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL: outer plexiform layer; ONL: outer nuclear layer; OS: outer segment; IS, inner segment. Scale bar, 50 μm. In addition to GCL, a few LacZ positive cells were detected in INL indicated by arrow heads. (C) Western blot analysis of VPS35 expression in retina homogenates from vps35+/+ and +/m at indicated ages. (D) Quantification analysis of percentage of LacZ positive cells. (E) Quantification analysis of VPS35 protein levels in retina from indicated age-groups of vps35+/+ and +/m mice. In (D-E), mean+/-SEM (n = 5) were presented.

Mentions: To investigate the potential role of VPS35 in retina, we first examined vps35’s expression in mouse retina by taking advantage of vps35+/m mice, in which LacZ gene is knocked in the intron of vps35 gene, thus, the LacZ activity, under the control of vps35 promoter, can be used as a reporter for vps35’s expression [9,10,14]. The LacZ activity was detected in developing mouse retinas from embryonic 12.5 to all the ages examined (Figure 1A and data not shown). Interestingly, this LacZ activity was mainly distributed in the ganglion cell layer (GCL) of vps35+/m retinas (Figure 1A). Higher power imaging analysis showed few X-gal (ß-galactosidase) positive cells in the inner plexiform (IPL) and upper inner nuclear (INL) layers, in addition to GCL (Figure 1B). Note that not all of the cells in GCL were LacZ positive (Figure 1B), and the ratio of LacZ positive cells over total cells in GCL was around 30%, which was reduced in aged retina (Figures 1A-D). These results suggest that vps35 is mainly expressed in developing mouse RGCs, and may be decreased during aging.


Vps35 haploinsufficiency results in degenerative-like deficit in mouse retinal ganglion neurons and impairment of optic nerve injury-induced gliosis.

Liu W, Tang FL, Erion J, Xiao H, Ye J, Xiong WC - Mol Brain (2014)

Vps35 expression in developing mouse retinas. (A) X-gal staining (Blue color) showed lacZ gene expression in the retina of vps35+/m mice at indicated ages. Scale bar, 200 μm. (B) The high magnification of X-gal staining images was shown. GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL: outer plexiform layer; ONL: outer nuclear layer; OS: outer segment; IS, inner segment. Scale bar, 50 μm. In addition to GCL, a few LacZ positive cells were detected in INL indicated by arrow heads. (C) Western blot analysis of VPS35 expression in retina homogenates from vps35+/+ and +/m at indicated ages. (D) Quantification analysis of percentage of LacZ positive cells. (E) Quantification analysis of VPS35 protein levels in retina from indicated age-groups of vps35+/+ and +/m mice. In (D-E), mean+/-SEM (n = 5) were presented.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4016418&req=5

Figure 1: Vps35 expression in developing mouse retinas. (A) X-gal staining (Blue color) showed lacZ gene expression in the retina of vps35+/m mice at indicated ages. Scale bar, 200 μm. (B) The high magnification of X-gal staining images was shown. GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL: outer plexiform layer; ONL: outer nuclear layer; OS: outer segment; IS, inner segment. Scale bar, 50 μm. In addition to GCL, a few LacZ positive cells were detected in INL indicated by arrow heads. (C) Western blot analysis of VPS35 expression in retina homogenates from vps35+/+ and +/m at indicated ages. (D) Quantification analysis of percentage of LacZ positive cells. (E) Quantification analysis of VPS35 protein levels in retina from indicated age-groups of vps35+/+ and +/m mice. In (D-E), mean+/-SEM (n = 5) were presented.
Mentions: To investigate the potential role of VPS35 in retina, we first examined vps35’s expression in mouse retina by taking advantage of vps35+/m mice, in which LacZ gene is knocked in the intron of vps35 gene, thus, the LacZ activity, under the control of vps35 promoter, can be used as a reporter for vps35’s expression [9,10,14]. The LacZ activity was detected in developing mouse retinas from embryonic 12.5 to all the ages examined (Figure 1A and data not shown). Interestingly, this LacZ activity was mainly distributed in the ganglion cell layer (GCL) of vps35+/m retinas (Figure 1A). Higher power imaging analysis showed few X-gal (ß-galactosidase) positive cells in the inner plexiform (IPL) and upper inner nuclear (INL) layers, in addition to GCL (Figure 1B). Note that not all of the cells in GCL were LacZ positive (Figure 1B), and the ratio of LacZ positive cells over total cells in GCL was around 30%, which was reduced in aged retina (Figures 1A-D). These results suggest that vps35 is mainly expressed in developing mouse RGCs, and may be decreased during aging.

Bottom Line: VPS35 (vacuolar protein sorting 35) is a major component of retromer that selectively promotes endosome-to-Golgi retrieval of transmembrane proteins.RGCs from young adult Vps35 heterozygotes (Vps35+/m) show degenerative-like features, such as dystrophic dendrites, reduced axon fibers, and increased TUNEL labeled RGCs.Additionally, gliosis in the optic nerve is transiently elevated in neonatal, but reduced in aged Vps35+/m mice.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ophthalmology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China. yejian1979@163.com.

ABSTRACT
VPS35 (vacuolar protein sorting 35) is a major component of retromer that selectively promotes endosome-to-Golgi retrieval of transmembrane proteins. Dysfunction of retromer is a risk factor for the pathogenesis of Parkinson's disease (PD) and Alzheimer's disease (AD), both neuro-degeneration disorders. However, VPS35/retromer's function in retina or the contribution of Vps35-deficiency to retinal neuro-degenerative disorders has not been investigated. Here we provide evidence for a role of VPS35 in mouse retinal ganglion cell (RGC) survival and regeneration. VPS35 is selectively expressed in developing mouse RGCs. RGCs from young adult Vps35 heterozygotes (Vps35+/m) show degenerative-like features, such as dystrophic dendrites, reduced axon fibers, and increased TUNEL labeled RGCs. Additionally, gliosis in the optic nerve is transiently elevated in neonatal, but reduced in aged Vps35+/m mice. Optic nerve injury-induced gliosis is also attenuated in Vps35+/m mice. These results suggest that Vps35 is necessary for mouse RGC survival and regeneration, and Vps35-deficiency may contribute to the pathogenesis of retinal ganglion neuro-degeneration, a critical pathology leading to the blindness of many retinal degenerative disorders.

Show MeSH
Related in: MedlinePlus