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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.

No MeSH data available.


Molecular interaction network by Ingenuity Pathway Analysis.Down-regulation in green, up-regulation marked in red. A = Activation, LO = Localization, E = Expression, PD = Protein/DNA interaction, L = molecular cleavage, P = Phosphorylation. ANXA5 = Annexin V, CYCS = Cytochrome c, somatic, ATPB1 = Calcium-transporting ATPase 1, Hist1h1e = Histone H1, H3F3B = Histone H3, H2AFZ = Histone H2A.Z, MYC = myc proto-oncogen
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pone.0175451.g007: Molecular interaction network by Ingenuity Pathway Analysis.Down-regulation in green, up-regulation marked in red. A = Activation, LO = Localization, E = Expression, PD = Protein/DNA interaction, L = molecular cleavage, P = Phosphorylation. ANXA5 = Annexin V, CYCS = Cytochrome c, somatic, ATPB1 = Calcium-transporting ATPase 1, Hist1h1e = Histone H1, H3F3B = Histone H3, H2AFZ = Histone H2A.Z, MYC = myc proto-oncogen

Mentions: The mechanism by which β-crystallin B2 exerts its neuroprotective function remains obscure, but a connection to a chaperone function might be possible. Certainly, other groups claim that it might act via CNTF [25]. By comparing mass-spectrometric LFQ intensities from crystallin injected eyes to IOP treated animals, we found clear evidence for shifts in calcium dependent signaling, like annexin A5 and calcium-transporting ATPase 1. Annexin A5, which was found down-regulated with a fold-change of 0.053 in crystallin animals, is not only a marker for apoptosis [53], but is cross-linked to the respective cellular calcium level. Annexin A5 is connected to cytochrome C via the mitogen-activated protein kinase 1 [54]. Cytochrome C, which is released from mitochondria, depending on the calcium level, is known as a direct driver for apoptosis by activating caspase 9 [55]. Down-regulation of somatic cytochrome C through crystallin injection might be a reason for the lower RGC apoptosis rate (Fig 7).


Intravitreal injection of β -crystallin B2 improves retinal ganglion cell survival in an experimental animal model of glaucoma
Molecular interaction network by Ingenuity Pathway Analysis.Down-regulation in green, up-regulation marked in red. A = Activation, LO = Localization, E = Expression, PD = Protein/DNA interaction, L = molecular cleavage, P = Phosphorylation. ANXA5 = Annexin V, CYCS = Cytochrome c, somatic, ATPB1 = Calcium-transporting ATPase 1, Hist1h1e = Histone H1, H3F3B = Histone H3, H2AFZ = Histone H2A.Z, MYC = myc proto-oncogen
© Copyright Policy
Related In: Results  -  Collection

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

pone.0175451.g007: Molecular interaction network by Ingenuity Pathway Analysis.Down-regulation in green, up-regulation marked in red. A = Activation, LO = Localization, E = Expression, PD = Protein/DNA interaction, L = molecular cleavage, P = Phosphorylation. ANXA5 = Annexin V, CYCS = Cytochrome c, somatic, ATPB1 = Calcium-transporting ATPase 1, Hist1h1e = Histone H1, H3F3B = Histone H3, H2AFZ = Histone H2A.Z, MYC = myc proto-oncogen
Mentions: The mechanism by which β-crystallin B2 exerts its neuroprotective function remains obscure, but a connection to a chaperone function might be possible. Certainly, other groups claim that it might act via CNTF [25]. By comparing mass-spectrometric LFQ intensities from crystallin injected eyes to IOP treated animals, we found clear evidence for shifts in calcium dependent signaling, like annexin A5 and calcium-transporting ATPase 1. Annexin A5, which was found down-regulated with a fold-change of 0.053 in crystallin animals, is not only a marker for apoptosis [53], but is cross-linked to the respective cellular calcium level. Annexin A5 is connected to cytochrome C via the mitogen-activated protein kinase 1 [54]. Cytochrome C, which is released from mitochondria, depending on the calcium level, is known as a direct driver for apoptosis by activating caspase 9 [55]. Down-regulation of somatic cytochrome C through crystallin injection might be a reason for the lower RGC apoptosis rate (Fig 7).

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.

No MeSH data available.