Limits...
ER stress in retinal degeneration in S334ter Rho rats.

Shinde VM, Sizova OS, Lin JH, LaVail MM, Gorbatyuk MS - PLoS ONE (2012)

Bottom Line: The S334ter rhodopsin (Rho) rat (line 4) bears the rhodopsin gene with an early termination codon at residue 334 that is a model for several such mutations found in human patients with autosomal dominant retinitis pigmentosa (ADRP).We determined that during the P12-P15 period, ER stress-related genes are strongly upregulated in transgenic retinas, resulting in the activation of the UPR that was confirmed using western blot analysis and RT-PCR.The activation of UPR was associated with the increased expression of JNK, Bik, Bim, Bid, Noxa, and Puma genes and cleavage of caspase-12 that together with activated calpains presumably compromise the integrity of the mitochondrial MPTP, leading to the release of pro-apoptotic AIF1 into the cytosol of S334ter Rho photoreceptor cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Anatomy, University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, Texas, United States of America.

ABSTRACT
The S334ter rhodopsin (Rho) rat (line 4) bears the rhodopsin gene with an early termination codon at residue 334 that is a model for several such mutations found in human patients with autosomal dominant retinitis pigmentosa (ADRP). The Unfolded Protein Response (UPR) is implicated in the pathophysiology of several retinal disorders including ADRP in P23H Rho rats. The aim of this study was to examine the onset of UPR gene expression in S334ter Rho retinas to determine if UPR is activated in ADRP animal models and to investigate how the activation of UPR molecules leads to the final demise of S334ter Rho photoreceptors. RT-PCR was performed to evaluate the gene expression profiles for the P10, P12, P15, and P21 stages of the development and progression of ADRP in S334ter Rho photoreceptors. We determined that during the P12-P15 period, ER stress-related genes are strongly upregulated in transgenic retinas, resulting in the activation of the UPR that was confirmed using western blot analysis and RT-PCR. The activation of UPR was associated with the increased expression of JNK, Bik, Bim, Bid, Noxa, and Puma genes and cleavage of caspase-12 that together with activated calpains presumably compromise the integrity of the mitochondrial MPTP, leading to the release of pro-apoptotic AIF1 into the cytosol of S334ter Rho photoreceptor cells. Therefore, two major cross-talking pathways, the UPR and mitochondrial MPTP occur in S334ter-4 Rho retina concomitantly and eventually promote the death of the photoreceptor cells.

Show MeSH

Related in: MedlinePlus

Relative expression of ER stress- and ERAD-related genes in S334ter-4 Rho retinas.The UPR gene expression was altered in S334ter-4 RHO retinas. Relative gene expression in S334tr Rho retina was measured on P10, P12, P15, P18 and P21 and a fold change was expressed as a ratio of S334ter-4Rho relative expression to SD relative expression. On P10, there was a significant reduction in the Ero1 gene expression suggesting that the ER homeostasis in S334ter-4 Rho retinas is imbalanced. The expression of this gene is decreased 2-fold (P<0.05, *) in S334ter-4 Rho retinas compared with SD retinas on P10. The increased expression of Calnexin (Cnx) and Atf4 genes are the first ER stress markers that respond to ER disturbance. The expression of these genes was increased 1.6- and 1.5-fold, respectively, (P<0.05, * in each case) on P10. On P12, the expression of other UPR upstream and downstream markers, such as Hsp40/Dnajc10, Ero1, Bip, eIf2a, Xbp1, Atf6 and Chop, were detected, which was indicated by relative increases of 1.8-, 1.8-, 1.5-, 1.9-, 1.6-, 1.8- and 1.6-fold, respectively, (P<0.05, * in each case with the exception of eIF2a where P<0.01, **). On P15, the Cnx, Ero1, eIf2a, Atf4 and Chop genes were expressed to a lesser extent or there was no significant difference in their expression levels in S334ter-4 Rho retinas compared with SD retinas. However, the Hsp40/Dnajc10, Bip, Xbp1 and ATf6 mRNAs were significantly induced on P15. Their relative expressions were 2-, 2-, 1.5- and 2-fold higher in S334ter-4 Rho retinas compared with the WT group (P<0.01 for Bip and Atf6, and P<0.05 for Hsp40/Dnajc10 and Xbp1). On P21, the expression of all genes was insignificant in the S334ter-4 Rho retinas compared with the SD retinas. Derl1 and Hrd1 gene expression was upregulated 1.5- and 1.6-fold on p10 and p12, respectively (P<0.05 in each case).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3303830&req=5

pone-0033266-g002: Relative expression of ER stress- and ERAD-related genes in S334ter-4 Rho retinas.The UPR gene expression was altered in S334ter-4 RHO retinas. Relative gene expression in S334tr Rho retina was measured on P10, P12, P15, P18 and P21 and a fold change was expressed as a ratio of S334ter-4Rho relative expression to SD relative expression. On P10, there was a significant reduction in the Ero1 gene expression suggesting that the ER homeostasis in S334ter-4 Rho retinas is imbalanced. The expression of this gene is decreased 2-fold (P<0.05, *) in S334ter-4 Rho retinas compared with SD retinas on P10. The increased expression of Calnexin (Cnx) and Atf4 genes are the first ER stress markers that respond to ER disturbance. The expression of these genes was increased 1.6- and 1.5-fold, respectively, (P<0.05, * in each case) on P10. On P12, the expression of other UPR upstream and downstream markers, such as Hsp40/Dnajc10, Ero1, Bip, eIf2a, Xbp1, Atf6 and Chop, were detected, which was indicated by relative increases of 1.8-, 1.8-, 1.5-, 1.9-, 1.6-, 1.8- and 1.6-fold, respectively, (P<0.05, * in each case with the exception of eIF2a where P<0.01, **). On P15, the Cnx, Ero1, eIf2a, Atf4 and Chop genes were expressed to a lesser extent or there was no significant difference in their expression levels in S334ter-4 Rho retinas compared with SD retinas. However, the Hsp40/Dnajc10, Bip, Xbp1 and ATf6 mRNAs were significantly induced on P15. Their relative expressions were 2-, 2-, 1.5- and 2-fold higher in S334ter-4 Rho retinas compared with the WT group (P<0.01 for Bip and Atf6, and P<0.05 for Hsp40/Dnajc10 and Xbp1). On P21, the expression of all genes was insignificant in the S334ter-4 Rho retinas compared with the SD retinas. Derl1 and Hrd1 gene expression was upregulated 1.5- and 1.6-fold on p10 and p12, respectively (P<0.05 in each case).

Mentions: Figure 2 demonstrates the results of RT-PCR analysis of the genes involved in the activation of ER stress signaling in S334ter-4 Rho rats. On P10 in transgenic retinas, calnexin (Cnx) and ATF4 gene expression was significantly upregulated 1.6- and 1.5-fold, respectively (0.9±0.05 in SD vs. 1.4±0.2 in S334ter-4 Rho and 0.9±0.04 in SD vs. 1.3±0.1 in S334ter-4 Rho, respectively, P<0.05 in both cases). Furthermore, Ero1 gene expression was downregulated 2-fold (1.2±0.18 in SD vs. 0.6±0.18 in S334ter-4 Rho, P<0.05). On P12, the number of genes involved in the ER stress response was extended and included the following: Cnx (2.1-fold increase; 0.62±0.09 in SD vs. 1.3±0.16 in S334ter-4 Rho, P<0.05), Hsp40/Dnajc10 (1.8-fold increase; 0.65±0.1 I SD vs. 1.21±0.18 in S334ter-4 Rho, P<0.05), Ero1 (1.8-fold increase; 0.8±0.13 in SD vs. 1.5±0.2 in S334ter-4 Rho), Bip (1.7-fold increase; 0.7±0.01 in SD vs. 1.2±0.1 in S334ter-4 Rho, P<0.05), eiF2a (1.9-fold increase; 0.80±0.13 in SD vs. 1.50±±0.2 in S334ter-4 Rho, P<0.01), Xbp1 (1.6-fold increase; 0.72±0.08 in SD vs. 1.17±0.13 in transgenic rats, P<0.05), Atf6 (1.8-fold increase; 0.64±0.09 in SD vs. 1.15±0.13 in S334ter-4 Rho, P<0.05) and Chop (1.5-fold increase; 0.8±0.05 in SD vs. 1.3±0.12 in S334ter-4 Rho, P<0.05). On P15, the expression of Cnx, Ero1, eIF2a and Atf4 dropped to different extents, and although in some cases, the expression level of these genes was higher than in the SD retinas, the relative expression of Chop protein was consistently 1.3-fold higher than in the SD retinas. On P15, the relative expression of the following genes was significantly elevated: Hsp40/Dnajc10 (2-fold increase; 0.6±0.12 in SD vs. 1.2±0.22 in S334ter-4 Rho, P<0.05), Bip (2-fold increase; 0.65±0.12 in SD vs. 1.32±0.16 in S334ter-4 Rho, P<0.01), Xbp1 (1.5-fold increase; 0.9±0.16 in SD vs. 1.36±0.17 in S334ter-4 Rho, P<0.05), Atf6 (greater than 2-fold increase; 0.60±0.17 in SD vs. 1.22±0.073 in transgenic rats, P<0.01). On P18, the expression levels of all genes analyzed dropped to the level of the SD retinas. The exception to this finding was the Chop gene, which exhibited upregulated expression in P18 retinas, and the Xbp1 gene, which was significantly downregulated in P18 S334ter-4 Rho retinas. Therefore, the data confirmed that the expression of ER stress-related genes, the eiF2a and Atf4 genes (the PERK pathway), the Atf6 gene (the ATF6 pathway) and the Xbp1 gene (the IRE1 pathway) were upregulated in P12–15 S334ter-4 Rho retinas.


ER stress in retinal degeneration in S334ter Rho rats.

Shinde VM, Sizova OS, Lin JH, LaVail MM, Gorbatyuk MS - PLoS ONE (2012)

Relative expression of ER stress- and ERAD-related genes in S334ter-4 Rho retinas.The UPR gene expression was altered in S334ter-4 RHO retinas. Relative gene expression in S334tr Rho retina was measured on P10, P12, P15, P18 and P21 and a fold change was expressed as a ratio of S334ter-4Rho relative expression to SD relative expression. On P10, there was a significant reduction in the Ero1 gene expression suggesting that the ER homeostasis in S334ter-4 Rho retinas is imbalanced. The expression of this gene is decreased 2-fold (P<0.05, *) in S334ter-4 Rho retinas compared with SD retinas on P10. The increased expression of Calnexin (Cnx) and Atf4 genes are the first ER stress markers that respond to ER disturbance. The expression of these genes was increased 1.6- and 1.5-fold, respectively, (P<0.05, * in each case) on P10. On P12, the expression of other UPR upstream and downstream markers, such as Hsp40/Dnajc10, Ero1, Bip, eIf2a, Xbp1, Atf6 and Chop, were detected, which was indicated by relative increases of 1.8-, 1.8-, 1.5-, 1.9-, 1.6-, 1.8- and 1.6-fold, respectively, (P<0.05, * in each case with the exception of eIF2a where P<0.01, **). On P15, the Cnx, Ero1, eIf2a, Atf4 and Chop genes were expressed to a lesser extent or there was no significant difference in their expression levels in S334ter-4 Rho retinas compared with SD retinas. However, the Hsp40/Dnajc10, Bip, Xbp1 and ATf6 mRNAs were significantly induced on P15. Their relative expressions were 2-, 2-, 1.5- and 2-fold higher in S334ter-4 Rho retinas compared with the WT group (P<0.01 for Bip and Atf6, and P<0.05 for Hsp40/Dnajc10 and Xbp1). On P21, the expression of all genes was insignificant in the S334ter-4 Rho retinas compared with the SD retinas. Derl1 and Hrd1 gene expression was upregulated 1.5- and 1.6-fold on p10 and p12, respectively (P<0.05 in each case).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3303830&req=5

pone-0033266-g002: Relative expression of ER stress- and ERAD-related genes in S334ter-4 Rho retinas.The UPR gene expression was altered in S334ter-4 RHO retinas. Relative gene expression in S334tr Rho retina was measured on P10, P12, P15, P18 and P21 and a fold change was expressed as a ratio of S334ter-4Rho relative expression to SD relative expression. On P10, there was a significant reduction in the Ero1 gene expression suggesting that the ER homeostasis in S334ter-4 Rho retinas is imbalanced. The expression of this gene is decreased 2-fold (P<0.05, *) in S334ter-4 Rho retinas compared with SD retinas on P10. The increased expression of Calnexin (Cnx) and Atf4 genes are the first ER stress markers that respond to ER disturbance. The expression of these genes was increased 1.6- and 1.5-fold, respectively, (P<0.05, * in each case) on P10. On P12, the expression of other UPR upstream and downstream markers, such as Hsp40/Dnajc10, Ero1, Bip, eIf2a, Xbp1, Atf6 and Chop, were detected, which was indicated by relative increases of 1.8-, 1.8-, 1.5-, 1.9-, 1.6-, 1.8- and 1.6-fold, respectively, (P<0.05, * in each case with the exception of eIF2a where P<0.01, **). On P15, the Cnx, Ero1, eIf2a, Atf4 and Chop genes were expressed to a lesser extent or there was no significant difference in their expression levels in S334ter-4 Rho retinas compared with SD retinas. However, the Hsp40/Dnajc10, Bip, Xbp1 and ATf6 mRNAs were significantly induced on P15. Their relative expressions were 2-, 2-, 1.5- and 2-fold higher in S334ter-4 Rho retinas compared with the WT group (P<0.01 for Bip and Atf6, and P<0.05 for Hsp40/Dnajc10 and Xbp1). On P21, the expression of all genes was insignificant in the S334ter-4 Rho retinas compared with the SD retinas. Derl1 and Hrd1 gene expression was upregulated 1.5- and 1.6-fold on p10 and p12, respectively (P<0.05 in each case).
Mentions: Figure 2 demonstrates the results of RT-PCR analysis of the genes involved in the activation of ER stress signaling in S334ter-4 Rho rats. On P10 in transgenic retinas, calnexin (Cnx) and ATF4 gene expression was significantly upregulated 1.6- and 1.5-fold, respectively (0.9±0.05 in SD vs. 1.4±0.2 in S334ter-4 Rho and 0.9±0.04 in SD vs. 1.3±0.1 in S334ter-4 Rho, respectively, P<0.05 in both cases). Furthermore, Ero1 gene expression was downregulated 2-fold (1.2±0.18 in SD vs. 0.6±0.18 in S334ter-4 Rho, P<0.05). On P12, the number of genes involved in the ER stress response was extended and included the following: Cnx (2.1-fold increase; 0.62±0.09 in SD vs. 1.3±0.16 in S334ter-4 Rho, P<0.05), Hsp40/Dnajc10 (1.8-fold increase; 0.65±0.1 I SD vs. 1.21±0.18 in S334ter-4 Rho, P<0.05), Ero1 (1.8-fold increase; 0.8±0.13 in SD vs. 1.5±0.2 in S334ter-4 Rho), Bip (1.7-fold increase; 0.7±0.01 in SD vs. 1.2±0.1 in S334ter-4 Rho, P<0.05), eiF2a (1.9-fold increase; 0.80±0.13 in SD vs. 1.50±±0.2 in S334ter-4 Rho, P<0.01), Xbp1 (1.6-fold increase; 0.72±0.08 in SD vs. 1.17±0.13 in transgenic rats, P<0.05), Atf6 (1.8-fold increase; 0.64±0.09 in SD vs. 1.15±0.13 in S334ter-4 Rho, P<0.05) and Chop (1.5-fold increase; 0.8±0.05 in SD vs. 1.3±0.12 in S334ter-4 Rho, P<0.05). On P15, the expression of Cnx, Ero1, eIF2a and Atf4 dropped to different extents, and although in some cases, the expression level of these genes was higher than in the SD retinas, the relative expression of Chop protein was consistently 1.3-fold higher than in the SD retinas. On P15, the relative expression of the following genes was significantly elevated: Hsp40/Dnajc10 (2-fold increase; 0.6±0.12 in SD vs. 1.2±0.22 in S334ter-4 Rho, P<0.05), Bip (2-fold increase; 0.65±0.12 in SD vs. 1.32±0.16 in S334ter-4 Rho, P<0.01), Xbp1 (1.5-fold increase; 0.9±0.16 in SD vs. 1.36±0.17 in S334ter-4 Rho, P<0.05), Atf6 (greater than 2-fold increase; 0.60±0.17 in SD vs. 1.22±0.073 in transgenic rats, P<0.01). On P18, the expression levels of all genes analyzed dropped to the level of the SD retinas. The exception to this finding was the Chop gene, which exhibited upregulated expression in P18 retinas, and the Xbp1 gene, which was significantly downregulated in P18 S334ter-4 Rho retinas. Therefore, the data confirmed that the expression of ER stress-related genes, the eiF2a and Atf4 genes (the PERK pathway), the Atf6 gene (the ATF6 pathway) and the Xbp1 gene (the IRE1 pathway) were upregulated in P12–15 S334ter-4 Rho retinas.

Bottom Line: The S334ter rhodopsin (Rho) rat (line 4) bears the rhodopsin gene with an early termination codon at residue 334 that is a model for several such mutations found in human patients with autosomal dominant retinitis pigmentosa (ADRP).We determined that during the P12-P15 period, ER stress-related genes are strongly upregulated in transgenic retinas, resulting in the activation of the UPR that was confirmed using western blot analysis and RT-PCR.The activation of UPR was associated with the increased expression of JNK, Bik, Bim, Bid, Noxa, and Puma genes and cleavage of caspase-12 that together with activated calpains presumably compromise the integrity of the mitochondrial MPTP, leading to the release of pro-apoptotic AIF1 into the cytosol of S334ter Rho photoreceptor cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Anatomy, University of North Texas Health Science Center, North Texas Eye Research Institute, Fort Worth, Texas, United States of America.

ABSTRACT
The S334ter rhodopsin (Rho) rat (line 4) bears the rhodopsin gene with an early termination codon at residue 334 that is a model for several such mutations found in human patients with autosomal dominant retinitis pigmentosa (ADRP). The Unfolded Protein Response (UPR) is implicated in the pathophysiology of several retinal disorders including ADRP in P23H Rho rats. The aim of this study was to examine the onset of UPR gene expression in S334ter Rho retinas to determine if UPR is activated in ADRP animal models and to investigate how the activation of UPR molecules leads to the final demise of S334ter Rho photoreceptors. RT-PCR was performed to evaluate the gene expression profiles for the P10, P12, P15, and P21 stages of the development and progression of ADRP in S334ter Rho photoreceptors. We determined that during the P12-P15 period, ER stress-related genes are strongly upregulated in transgenic retinas, resulting in the activation of the UPR that was confirmed using western blot analysis and RT-PCR. The activation of UPR was associated with the increased expression of JNK, Bik, Bim, Bid, Noxa, and Puma genes and cleavage of caspase-12 that together with activated calpains presumably compromise the integrity of the mitochondrial MPTP, leading to the release of pro-apoptotic AIF1 into the cytosol of S334ter Rho photoreceptor cells. Therefore, two major cross-talking pathways, the UPR and mitochondrial MPTP occur in S334ter-4 Rho retina concomitantly and eventually promote the death of the photoreceptor cells.

Show MeSH
Related in: MedlinePlus