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- Agudo, Marta, et al.
(författare)
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Immediate Upregulation of Proteins Belonging to Different Branches of the Apoptotic Cascade in the Retina after Optic Nerve Transection and Optic Nerve Crush
- 2009
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 50:1, s. 424-431
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To further investigate the molecular signals underlying optic nerve (ON) injury we have analyzed in adult control, ON transected and ON crushed retinas, the expression pattern and time-course regulation of the following proteins, all of which are linked to apoptosis through different pathways: Stat 1, Caspase 11 (inflammation and death), Cathepsins C and B (lysosomal death pathway), Calpain 1 (endoplasmic reticulum stress), Calreticulin (apoptosis marker), Jun (early response) and Ahr (cell cycle arrest). Methods: Adult female rats were subjected to either intraorbital optic nerve transection (IONT) or intraorbital optic nerve crush (IONC). Protein from naive and ON injured adult rat retinas was extracted at increasing time-points post-lesion and western blotting experiments carried out. For immnuhistofluorescence analyses, retinal ganglion cells (RGCs) were retrogradelly identified with fluorogold applied to the superior colliculi one week before injury. Results: Western blotting analyses revealed up-regulation of all the analyzed proteins as soon as 12 hours post-lesion (hpl) peaking at 48hpl, in agreement with our previous RNA studies1. Furthermore, immunohistofluorescence to radial sections show that all of them, but Stat1, are expressed by the primarily injured neurons, the RGCs, as seen by colocalization with FG. Conclusions: All analyzed proteins were up-regulated in the retina after IONT or IONC as soon as 12hpl, indicating that ON injury regulates several branches of the apoptotic cascade and suggesting that commitment to death might be an earlier event than previously anticipated.
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| 2. |
- All-Ericsson, Charlotta, et al.
(författare)
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c-Kit-dependent growth of uveal melanoma cells : a potential therapeutic target?
- 2004
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 45:7, s. 2075-82
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study was conducted to investigate the expression and functional impact of the proto-oncogene c-kit in uveal melanoma. METHODS: Based on immunohistochemical (IHC) study of paraffin-embedded specimens from 134 uveal melanomas and Western blot analysis on eight fresh-frozen samples the expression of c-kit in uveal melanoma was studied. Furthermore, the phosphorylation of c-kit and the impact of the tyrosine kinase inhibitor STI571 was examined in the three uveal melanoma cell lines OCM-1, OCM-3, and 92-1. RESULTS: Eighty-four of 134 paraffin-embedded samples and six of eight fresh-frozen samples expressed c-kit. c-Kit was strongly expressed and tyrosine phosphorylated in cultured uveal melanoma cells compared with cutaneous melanoma cells. Moreover, in contrast to cutaneous melanoma cell lines c-kit maintained a high phosphorylation level in serum-depleted uveal melanoma cells. No activation-related mutations in exon 11 of the KIT gene were found. On the contrary, expression of the stem cell growth factor (c-kit ligand) was detected in all three uveal melanoma cell lines, suggesting the presence of autocrine (paracrine) stimulation pathways. Treatment of uveal melanoma cell lines with STI571, which blocks c-kit autophosphorylation, resulted in cell death. The IC(50) of the inhibitory effects on c-kit phosphorylation and cell proliferation was of equal size and less than 2.5 microM. CONCLUSIONS: The results confirm that c-kit is vastly expressed in uveal melanoma, suggest that the c-kit molecular pathway may be important in uveal melanoma growth, and point to its use as a target for therapy with STI571.
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| 3. |
- Ayala, Marcelo, et al.
(författare)
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p53 expression and apoptosis in the lens after ultraviolet radiation exposure
- 2007
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 48:9, s. 4187-4191
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To localize p53 protein and active caspase-3 in the albino rat lens and to compare p53 mRNA and active caspase-3 expression in ultraviolet radiation (UVR) 300 nm exposed lenses and their contralateral nonexposed controls. METHODS: Ten Sprague-Dawley albino rats were unilaterally exposed to 8 kJ/m(2) UVR, and the contralateral eyes were left nonexposed. In total, four exposed lenses and their respective contralateral nonexposed lenses were analyzed by immunohistochemistry to localize p53 and active caspase-3. In addition, six exposed and contralateral nonexposed lenses were analyzed by real-time RT-PCR. Quantified p53 and caspase-3 expression were compared between the in vivo UVR 300 nm exposed lenses and the contralateral nonexposed lenses. RESULTS: All lenses exposed to UVR developed cataract. Immunohistochemistry showed that p53 and active caspase-3 were localized in the lens epithelial cells. Quantified p53 and caspase-3 expression were significantly higher in lenses exposed to UVR than in nonexposed lenses. CONCLUSIONS: p53 and caspase-3 expression increase in lens epithelial cells after UVR exposure. In the lens, apoptosis induced by UVR may be associated with increased p53 expression.
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| 8. |
- Harun-Or-Rashid, Mohammad, et al.
(författare)
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Alpha2-Adrenergic-Agonist Brimonidine Stimulates Negative Feedback and Attenuates Injury-Induced Phospho-ERK and Dedifferentiation of Chicken Müller Cells
- 2015
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 56:10, s. 5933-5945
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:Retinal injury induces Müller cell dedifferentiation by activating extracellular signal-regulated kinase (ERK) signaling. Stimulation of α2-adrenergic receptors protects against injury but also activates ERK in Müller cells. The purpose of this work was to study the effect of α2-adrenergic signaling on injury-induced ERK and Müller cell dedifferentiation. We tested the hypothesis that α2-stimulation triggers negative feedback regulation of the injury-induced ERK pathway that attenuates Müller cell dedifferentiation.Methods:Chicken retina injured by N-methyl-D-aspartate and cultured primary Müller cells were stimulated by the α2-adrenergic agonist brimonidine. Immunostaining, quantitative RT-PCR, and Western blot techniques in combination with receptor blockers were used for analysis of the cellular responses.Results:Alpha2-adrenergic receptor stimulation attenuated injury-induced ERK activation and dedifferentiation of Müller cells as seen by decreased phospho-ERK, expression of transitin, and retinal progenitor cell genes. The attenuation was concomitant with a synergistic upregulation of several negative ERK-signal feedback regulators including ERK-phosphatases, Raf1-, and growth factor receptor–binding proteins. The results were also seen in cultures of primary Müller cells.Conclusions:Alpha2-adrenergic signaling on Müller cells elicits an intracellular attenuation of the injury response that comprises negative ERK-signaling feedback leading to attenuated Müller cell dedifferentiation. The implications of this study are that adrenergic stress signals may directly modulate glial function in retina and that α2-adrenergic receptor pharmacology may be used to control glial injury response.
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| 9. |
- Harun-Or-Rashid, Mohammad, et al.
(författare)
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Transactivation of EGF Receptors in Chicken Muller Cells by α2A-Adrenergic Receptors Stimulated by Brimonidine
- 2014
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 55:6, s. 3385-3394
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: α2-Adrenergic receptor agonists are used in glaucoma treatment and have been shown to have some neuroprotective effects. We performed this study to test the hypothesis that epidermal growth factor receptors on chicken Müller cells are transactivated by α2-adrenergic receptors and we focused on the extracellular signal-activated kinases 1/2 (ERK) pathway. Methods: Embryonic chicken retina and cultures of primary Müller cells were stimulated by α2-adrenergic receptor agonist brimonidine. Immunostaining, qRT-PCR and western blot techniques in combination with Src-, epidermal growth factor receptor kinase-, and matrix metalloproteinase inhibitors were used for analysis of the cellular responses. Results: Our results showed that Müller cells express α2A-adrenergic receptors in vivo and in vitro and that brimonidine triggered a robust and transient phosphorylation of ERK1/2. This ERK-response was Src-kinase dependent, associated with tyrosine phosphorylation of epidermal growth factor receptors (phospho-Y1068, Y1173) and was mediated by matrix metalloproteinase-activity on the Müller cells. Conclusions: Müller cells express the α2A-adrenergic receptor and brimonidine triggers both Src-kinase- and matrix metalloproteinase-mediated autocrine ligand-dependent activation of epidermal growth factor receptors on Müller cell. This response is consistent with transactivation of epidermal growth factor receptors by stimulation of α2-adrenergic receptors.
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