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Intravitreal injection of β -crystallin B2 improves retinal ganglion cell survival in an experimental animal model of glaucoma

View Article: PubMed Central - PubMed

ABSTRACT

Purpose of this study was to investigate firstly specific proteomic changes within the retina in the course of an animal glaucoma model and to identify secondly new approaches for neuroprotective, therapeutic options in glaucoma by addressing those specific changes. Intraocular pressure was elevated through cauterization of episcleral veins in adult Sprague Dawley rats. Molecular and morphological changes were surveyed using mass spectrometry, optical coherence tomography as well as immunohistochemical cross section- and flat mount stainings. By quantifying more than 1500 retinal proteins, it was found that the HspB5 protein and numerous beta-crystallins showed a uniform and unique shifting expression pattern as a result of different periods of elevated IOP exposure. Crystallins showed a significant downregulation (p<0.05) after 3 weeks of elevated IOP and an upregulation after 7 weeks. Counteracting those typical changes, an intravitreal injection of β-crystallin B2 at the time of IOP elevation was found to reduce retinal ganglion cell loss (p<0.05), decrease of the retinal nerve fiber layer (p<0.05) and impairment of the optic nerve. Ultimately, proteomic data revealed that β-crystallin B2 might influence calcium-depended cell signaling pathways with severe effect on apoptosis and gene regulation. In this context especially annexin A5, calcium-transporting ATPase 1 and various histone proteins seem to play a major role.

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β-crystallin B2 staining in retinal cross-sections.IHC staining could validate the results from mass-spectrometric featured proteomics analyses. After 3 weeks of IOP elevation, almost no β-crystallin B2 could be detected in the retina cross section (n = 3), while a strong increase of protein level could be verified after 7 weeks of elevated IOP (n = 3). Injection of β-crystallin B2 seems to change the protein level in retinal cells after 3 weeks of IOP elevation considerably due to cellular uptake of the crystallin, predominantly by the RGC layer (n = 4).
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pone.0175451.g004: β-crystallin B2 staining in retinal cross-sections.IHC staining could validate the results from mass-spectrometric featured proteomics analyses. After 3 weeks of IOP elevation, almost no β-crystallin B2 could be detected in the retina cross section (n = 3), while a strong increase of protein level could be verified after 7 weeks of elevated IOP (n = 3). Injection of β-crystallin B2 seems to change the protein level in retinal cells after 3 weeks of IOP elevation considerably due to cellular uptake of the crystallin, predominantly by the RGC layer (n = 4).

Mentions: Hereof, β-crystallin B2 was down-regulated with a fold-change of 0.19 (p<0.05, log2 = -2.4) at the early timepoint 1 and up-regulated with a fold-change of 1.8 (log2 = 0.85) at the later timepoint 2. The mass-spectrometric results for β-crystallin B2 could further be validated with immunohistochemical staining against β-crystallin B2 in retinal cross-sections. The staining showed the clear increase of β-crystallin B2 in the retinal tissues, which were exposed to 7 weeks of elevated IOP, compared to the 3 weeks’ group. Furthermore, staining of the retinal tissue, which was exposed to elevated IOP for only 3 weeks, but received an intravitreal injection of β-crystallin B2, showed considerable indication of cellular uptake of the injected β-crystallin B2, especially within the RGC layer (Fig 4).


Intravitreal injection of β -crystallin B2 improves retinal ganglion cell survival in an experimental animal model of glaucoma
β-crystallin B2 staining in retinal cross-sections.IHC staining could validate the results from mass-spectrometric featured proteomics analyses. After 3 weeks of IOP elevation, almost no β-crystallin B2 could be detected in the retina cross section (n = 3), while a strong increase of protein level could be verified after 7 weeks of elevated IOP (n = 3). Injection of β-crystallin B2 seems to change the protein level in retinal cells after 3 weeks of IOP elevation considerably due to cellular uptake of the crystallin, predominantly by the RGC layer (n = 4).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC5383327&req=5

pone.0175451.g004: β-crystallin B2 staining in retinal cross-sections.IHC staining could validate the results from mass-spectrometric featured proteomics analyses. After 3 weeks of IOP elevation, almost no β-crystallin B2 could be detected in the retina cross section (n = 3), while a strong increase of protein level could be verified after 7 weeks of elevated IOP (n = 3). Injection of β-crystallin B2 seems to change the protein level in retinal cells after 3 weeks of IOP elevation considerably due to cellular uptake of the crystallin, predominantly by the RGC layer (n = 4).
Mentions: Hereof, β-crystallin B2 was down-regulated with a fold-change of 0.19 (p<0.05, log2 = -2.4) at the early timepoint 1 and up-regulated with a fold-change of 1.8 (log2 = 0.85) at the later timepoint 2. The mass-spectrometric results for β-crystallin B2 could further be validated with immunohistochemical staining against β-crystallin B2 in retinal cross-sections. The staining showed the clear increase of β-crystallin B2 in the retinal tissues, which were exposed to 7 weeks of elevated IOP, compared to the 3 weeks’ group. Furthermore, staining of the retinal tissue, which was exposed to elevated IOP for only 3 weeks, but received an intravitreal injection of β-crystallin B2, showed considerable indication of cellular uptake of the injected β-crystallin B2, especially within the RGC layer (Fig 4).

View Article: PubMed Central - PubMed

ABSTRACT

Purpose of this study was to investigate firstly specific proteomic changes within the retina in the course of an animal glaucoma model and to identify secondly new approaches for neuroprotective, therapeutic options in glaucoma by addressing those specific changes. Intraocular pressure was elevated through cauterization of episcleral veins in adult Sprague Dawley rats. Molecular and morphological changes were surveyed using mass spectrometry, optical coherence tomography as well as immunohistochemical cross section- and flat mount stainings. By quantifying more than 1500 retinal proteins, it was found that the HspB5 protein and numerous beta-crystallins showed a uniform and unique shifting expression pattern as a result of different periods of elevated IOP exposure. Crystallins showed a significant downregulation (p&lt;0.05) after 3 weeks of elevated IOP and an upregulation after 7 weeks. Counteracting those typical changes, an intravitreal injection of &beta;-crystallin B2 at the time of IOP elevation was found to reduce retinal ganglion cell loss (p&lt;0.05), decrease of the retinal nerve fiber layer (p&lt;0.05) and impairment of the optic nerve. Ultimately, proteomic data revealed that &beta;-crystallin B2 might influence calcium-depended cell signaling pathways with severe effect on apoptosis and gene regulation. In this context especially annexin A5, calcium-transporting ATPase 1 and various histone proteins seem to play a major role.

No MeSH data available.


Related in: MedlinePlus