AIM: To investigate the effect of high concentration of glucose(HCG) on double stranded RNA-activated protein kinase-like ER kinase(PERK)-eukaryotic initiation factor-2α(eIF2α)-transcription factor C/EBP homologous ...AIM: To investigate the effect of high concentration of glucose(HCG) on double stranded RNA-activated protein kinase-like ER kinase(PERK)-eukaryotic initiation factor-2α(eIF2α)-transcription factor C/EBP homologous protein(CHOP)-cysteine aspartate specific proteinase(caspase-12) signaling pathway activation and apoptosis in rabbit corneal epithelial cells(RCECs). METHODS: RCECs were treated by different concentrations of glucose for 0-48 h. The expressions of PERK, p-PERK, eIF2α, p-eIF2α, 78 k Da glucose-regulated protein 78(GRP78), CHOP, B-cell lymphoma 2(Bcl-2), B-cell lymphoma-2-associated X protein(Bax) and caspase-12 were determined by Western blot. Apoptosis was detected by TUNEL assay. Meanwhile, the function of PERK-eI F2α-CHOP-caspase-12 signaling pathway activation in high glucose-induced apoptosis was evaluated using PERK inhibitor, GSK2606414. RESULTS: HCG significantly promoted the expression of p-PERK, p-eIF2α, GRP78, CHOP, Bax and cleaved caspase-12 in RCECs(P<0.05), while remarkably decreased the expression of Bcl-2 and caspase-12(P<0.05), and the alterations caused by glucose were in concentration-and time-dependent manners. Meanwhile, PERK and eIF2α expressions were not affected in all groups(P>0.05). TUNEL assay showed that the apoptosis rate of RCECs in the HCG group increased significantly in contrast with that in the normal concentration of glucose or osmotic pressure control group(P<0.05), and the apoptosis rate increased with the increase of glucose concentration within limits(P<0.05). GSK2606414 down-regulated the expression of p-PERK and p-eI F2α in the HCG group(P<0.05), while still did not affect the expression of PERK and eIF2α among groups(P>0.05). Correspondingly, GSK2606414 also significantly reduced the apoptosis rate induced by high glucose(P<0.05). CONCLUSION: HCG activates PERK-eIF2α-CHOPcaspase-12 signaling pathway and promotes apoptosis of RCECs.展开更多
AIM: To investigate the expression of insulin-like growth factor binding protein-6(IGFBP-6) in a proliferative vitreoretinopathy(PVR) model and its effects on proliferation and migration in retinal pigment epithelial(...AIM: To investigate the expression of insulin-like growth factor binding protein-6(IGFBP-6) in a proliferative vitreoretinopathy(PVR) model and its effects on proliferation and migration in retinal pigment epithelial(RPE) cells. ·METHODS: A PVR Wistar rat model was established by the intravitreal injection of RPE-J cells combined with platelet-rich plasma(PRP). The expression levels of IGFBP-6 were tested by ELISA. ARPE-19 cell proliferation was evaluated by the MTS method,and cell migration was evaluated by wound healing assays. ·RESULTS: The success rate of the PVR model was 89.3%(25/28). IGFBP-6 was expressed at higher levels in the vitreous,serum and retina of rats experiencing advanced PVR(grade 3) than in the control group(vitreous: 152.80 ±15.08ng/mL vs 105.44 ±24.81ng/mL,P > 0.05; serum: 93.48 ±9.27ng/mL vs 80.59 ±5.20ng/mL,P < 0.05; retina: 3.02±0.38ng/mg vs 2.05±0.53ng/mg,P <0.05). In vitro,IGFBP-6(500ng/mL) inhibited the IGF-II(50ng/mL) induced ARPE-19 cell proliferation(OD value at 24h: from 1.38±0.05 to 1.30±0.02; 48h: from 1.44±0.06 to 1.35± 0.05). However,it did not affect basal or VEGF-,TGF-β-and PDGF-induced cell proliferation. IGFBP-6(500ng/ml) reduced the IGF-II(50ng/mL)-induced would healing rate [24h: from(43.91 ±3.85)% to(29.76 ±2.49)%; 48h: from(66.09±1.67)% to(59.88±3.43)%]. ·CONCLUSION: Concentrations of IGFBP-6 increased in the vitreous,serum,and retinas only in advanced PVR in vivo. IGFBP-6 also inhibited IGF-II-induced cell proliferation in a not dose or time dependent manner and migration. IGFBP-6 participates in the development of PVR and might play a protective role in PVR.展开更多
基金Supported by Shanghai Natural Science Foundation (No.19ZR1450500)National Foundation Cultivation Project of Tongji University (No.22120180285)the Good Physician Training Project of Yangpu District, Shanghai
文摘AIM: To investigate the effect of high concentration of glucose(HCG) on double stranded RNA-activated protein kinase-like ER kinase(PERK)-eukaryotic initiation factor-2α(eIF2α)-transcription factor C/EBP homologous protein(CHOP)-cysteine aspartate specific proteinase(caspase-12) signaling pathway activation and apoptosis in rabbit corneal epithelial cells(RCECs). METHODS: RCECs were treated by different concentrations of glucose for 0-48 h. The expressions of PERK, p-PERK, eIF2α, p-eIF2α, 78 k Da glucose-regulated protein 78(GRP78), CHOP, B-cell lymphoma 2(Bcl-2), B-cell lymphoma-2-associated X protein(Bax) and caspase-12 were determined by Western blot. Apoptosis was detected by TUNEL assay. Meanwhile, the function of PERK-eI F2α-CHOP-caspase-12 signaling pathway activation in high glucose-induced apoptosis was evaluated using PERK inhibitor, GSK2606414. RESULTS: HCG significantly promoted the expression of p-PERK, p-eIF2α, GRP78, CHOP, Bax and cleaved caspase-12 in RCECs(P<0.05), while remarkably decreased the expression of Bcl-2 and caspase-12(P<0.05), and the alterations caused by glucose were in concentration-and time-dependent manners. Meanwhile, PERK and eIF2α expressions were not affected in all groups(P>0.05). TUNEL assay showed that the apoptosis rate of RCECs in the HCG group increased significantly in contrast with that in the normal concentration of glucose or osmotic pressure control group(P<0.05), and the apoptosis rate increased with the increase of glucose concentration within limits(P<0.05). GSK2606414 down-regulated the expression of p-PERK and p-eI F2α in the HCG group(P<0.05), while still did not affect the expression of PERK and eIF2α among groups(P>0.05). Correspondingly, GSK2606414 also significantly reduced the apoptosis rate induced by high glucose(P<0.05). CONCLUSION: HCG activates PERK-eIF2α-CHOPcaspase-12 signaling pathway and promotes apoptosis of RCECs.
文摘AIM: To investigate the expression of insulin-like growth factor binding protein-6(IGFBP-6) in a proliferative vitreoretinopathy(PVR) model and its effects on proliferation and migration in retinal pigment epithelial(RPE) cells. ·METHODS: A PVR Wistar rat model was established by the intravitreal injection of RPE-J cells combined with platelet-rich plasma(PRP). The expression levels of IGFBP-6 were tested by ELISA. ARPE-19 cell proliferation was evaluated by the MTS method,and cell migration was evaluated by wound healing assays. ·RESULTS: The success rate of the PVR model was 89.3%(25/28). IGFBP-6 was expressed at higher levels in the vitreous,serum and retina of rats experiencing advanced PVR(grade 3) than in the control group(vitreous: 152.80 ±15.08ng/mL vs 105.44 ±24.81ng/mL,P > 0.05; serum: 93.48 ±9.27ng/mL vs 80.59 ±5.20ng/mL,P < 0.05; retina: 3.02±0.38ng/mg vs 2.05±0.53ng/mg,P <0.05). In vitro,IGFBP-6(500ng/mL) inhibited the IGF-II(50ng/mL) induced ARPE-19 cell proliferation(OD value at 24h: from 1.38±0.05 to 1.30±0.02; 48h: from 1.44±0.06 to 1.35± 0.05). However,it did not affect basal or VEGF-,TGF-β-and PDGF-induced cell proliferation. IGFBP-6(500ng/ml) reduced the IGF-II(50ng/mL)-induced would healing rate [24h: from(43.91 ±3.85)% to(29.76 ±2.49)%; 48h: from(66.09±1.67)% to(59.88±3.43)%]. ·CONCLUSION: Concentrations of IGFBP-6 increased in the vitreous,serum,and retinas only in advanced PVR in vivo. IGFBP-6 also inhibited IGF-II-induced cell proliferation in a not dose or time dependent manner and migration. IGFBP-6 participates in the development of PVR and might play a protective role in PVR.
