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Polycomb repressive complex 2 regulates MiR-200b in retinal endothelial cells: potential relevance in diabetic retinopathy.

Ruiz MA, Feng B, Chakrabarti S - PLoS ONE (2015)

Bottom Line: Histone methyltransferase complex, Polycomb Repressive Complex 2 (PRC2), has been shown to repress miRNAs in neoplastic process.We show that human retinal microvascular endothelial cells exposed to high levels of glucose regulate miR-200b repression through histone methylation and that inhibition of PRC2 increases miR-200b while reducing VEGF.This research established a repressive relationship between PRC2 and miR-200b, providing evidence of a novel mechanism of miRNA regulation through histone methylation.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.

ABSTRACT
Glucose-induced augmented vascular endothelial growth factor (VEGF) production is a key event in diabetic retinopathy. We have previously demonstrated that downregulation of miR-200b increases VEGF, mediating structural and functional changes in the retina in diabetes. However, mechanisms regulating miR-200b in diabetes are not known. Histone methyltransferase complex, Polycomb Repressive Complex 2 (PRC2), has been shown to repress miRNAs in neoplastic process. We hypothesized that, in diabetes, PRC2 represses miR-200b through its histone H3 lysine-27 trimethylation mark. We show that human retinal microvascular endothelial cells exposed to high levels of glucose regulate miR-200b repression through histone methylation and that inhibition of PRC2 increases miR-200b while reducing VEGF. Furthermore, retinal tissue from animal models of diabetes showed increased expression of major PRC2 components, demonstrating in vivo relevance. This research established a repressive relationship between PRC2 and miR-200b, providing evidence of a novel mechanism of miRNA regulation through histone methylation.

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PRC2 components are altered in animal models of diabetes and other endothelial cell types exposed to high glucose.A,B: Real time RT-PCR analysis of PRC2 component expression in animal retinal tissue from streptozotocin (STZ) induced diabetic and control animals. A: After 1 month of diabetes, VEGF expression was increased and miR-200b expression was decreased. Furthermore, EZH2, EED and SUZ12 levels were increased in rat retinal tissue from diabetic animals compared to control animals. B: After 2 months of diabetes, EZH2, EED and SUZ12 levels were increased in mouse retinal tissue of diabetic animals compared to controls. C,D,E: Real time RT-PCR analysis of VEGF, miR-200b and PRC2 components in HDMECs of various origins. In all groups, VEGF and miR-200b expression was altered. C: In non-diabetic adult HDMECs, EED and SUZ12 levels were significantly increased by HG. D,E: In HDMECs isolated from patients with diabetes (Type 1 & Type 2), EZH2, EED and SUZ12 were significantly increased in HG compared to NG controls. [HDMECs = human dermal microvascular endothelial cells, Type 1 = HDMECs isolated from a patient with type 1 diabetes, Type 2 = HDMECs isolated from a patient with type 2 diabetes, * p < 0.05 compared to control/NG; n = 6; data expressed as mean ± SEM, normalized to β-actin and expressed as a fold change of control].
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pone.0123987.g006: PRC2 components are altered in animal models of diabetes and other endothelial cell types exposed to high glucose.A,B: Real time RT-PCR analysis of PRC2 component expression in animal retinal tissue from streptozotocin (STZ) induced diabetic and control animals. A: After 1 month of diabetes, VEGF expression was increased and miR-200b expression was decreased. Furthermore, EZH2, EED and SUZ12 levels were increased in rat retinal tissue from diabetic animals compared to control animals. B: After 2 months of diabetes, EZH2, EED and SUZ12 levels were increased in mouse retinal tissue of diabetic animals compared to controls. C,D,E: Real time RT-PCR analysis of VEGF, miR-200b and PRC2 components in HDMECs of various origins. In all groups, VEGF and miR-200b expression was altered. C: In non-diabetic adult HDMECs, EED and SUZ12 levels were significantly increased by HG. D,E: In HDMECs isolated from patients with diabetes (Type 1 & Type 2), EZH2, EED and SUZ12 were significantly increased in HG compared to NG controls. [HDMECs = human dermal microvascular endothelial cells, Type 1 = HDMECs isolated from a patient with type 1 diabetes, Type 2 = HDMECs isolated from a patient with type 2 diabetes, * p < 0.05 compared to control/NG; n = 6; data expressed as mean ± SEM, normalized to β-actin and expressed as a fold change of control].

Mentions: Finally, the expression of PRC2 components was measured in retinal tissues of animal models of diabetes. VEGF expression was found to be increased while miR-200b expression was found decreased in the retinas of diabetic mice compared to controls (Fig 6A). We have previously demonstrated that VEGF and miR-200b expression is altered in the retinas of diabetic rats (21). Furthermore, EZH2, EED and SUZ12 were significantly increased in the retinal tissue of diabetic animals compared to non-diabetic controls (Fig 6A and 6B). These findings are consistent with the in vitro data produced in this project and suggests that PRC2-mediated regulation of miR-200b may be relevant in vivo.


Polycomb repressive complex 2 regulates MiR-200b in retinal endothelial cells: potential relevance in diabetic retinopathy.

Ruiz MA, Feng B, Chakrabarti S - PLoS ONE (2015)

PRC2 components are altered in animal models of diabetes and other endothelial cell types exposed to high glucose.A,B: Real time RT-PCR analysis of PRC2 component expression in animal retinal tissue from streptozotocin (STZ) induced diabetic and control animals. A: After 1 month of diabetes, VEGF expression was increased and miR-200b expression was decreased. Furthermore, EZH2, EED and SUZ12 levels were increased in rat retinal tissue from diabetic animals compared to control animals. B: After 2 months of diabetes, EZH2, EED and SUZ12 levels were increased in mouse retinal tissue of diabetic animals compared to controls. C,D,E: Real time RT-PCR analysis of VEGF, miR-200b and PRC2 components in HDMECs of various origins. In all groups, VEGF and miR-200b expression was altered. C: In non-diabetic adult HDMECs, EED and SUZ12 levels were significantly increased by HG. D,E: In HDMECs isolated from patients with diabetes (Type 1 & Type 2), EZH2, EED and SUZ12 were significantly increased in HG compared to NG controls. [HDMECs = human dermal microvascular endothelial cells, Type 1 = HDMECs isolated from a patient with type 1 diabetes, Type 2 = HDMECs isolated from a patient with type 2 diabetes, * p < 0.05 compared to control/NG; n = 6; data expressed as mean ± SEM, normalized to β-actin and expressed as a fold change of control].
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pone.0123987.g006: PRC2 components are altered in animal models of diabetes and other endothelial cell types exposed to high glucose.A,B: Real time RT-PCR analysis of PRC2 component expression in animal retinal tissue from streptozotocin (STZ) induced diabetic and control animals. A: After 1 month of diabetes, VEGF expression was increased and miR-200b expression was decreased. Furthermore, EZH2, EED and SUZ12 levels were increased in rat retinal tissue from diabetic animals compared to control animals. B: After 2 months of diabetes, EZH2, EED and SUZ12 levels were increased in mouse retinal tissue of diabetic animals compared to controls. C,D,E: Real time RT-PCR analysis of VEGF, miR-200b and PRC2 components in HDMECs of various origins. In all groups, VEGF and miR-200b expression was altered. C: In non-diabetic adult HDMECs, EED and SUZ12 levels were significantly increased by HG. D,E: In HDMECs isolated from patients with diabetes (Type 1 & Type 2), EZH2, EED and SUZ12 were significantly increased in HG compared to NG controls. [HDMECs = human dermal microvascular endothelial cells, Type 1 = HDMECs isolated from a patient with type 1 diabetes, Type 2 = HDMECs isolated from a patient with type 2 diabetes, * p < 0.05 compared to control/NG; n = 6; data expressed as mean ± SEM, normalized to β-actin and expressed as a fold change of control].
Mentions: Finally, the expression of PRC2 components was measured in retinal tissues of animal models of diabetes. VEGF expression was found to be increased while miR-200b expression was found decreased in the retinas of diabetic mice compared to controls (Fig 6A). We have previously demonstrated that VEGF and miR-200b expression is altered in the retinas of diabetic rats (21). Furthermore, EZH2, EED and SUZ12 were significantly increased in the retinal tissue of diabetic animals compared to non-diabetic controls (Fig 6A and 6B). These findings are consistent with the in vitro data produced in this project and suggests that PRC2-mediated regulation of miR-200b may be relevant in vivo.

Bottom Line: Histone methyltransferase complex, Polycomb Repressive Complex 2 (PRC2), has been shown to repress miRNAs in neoplastic process.We show that human retinal microvascular endothelial cells exposed to high levels of glucose regulate miR-200b repression through histone methylation and that inhibition of PRC2 increases miR-200b while reducing VEGF.This research established a repressive relationship between PRC2 and miR-200b, providing evidence of a novel mechanism of miRNA regulation through histone methylation.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, Western University, London, Ontario, Canada.

ABSTRACT
Glucose-induced augmented vascular endothelial growth factor (VEGF) production is a key event in diabetic retinopathy. We have previously demonstrated that downregulation of miR-200b increases VEGF, mediating structural and functional changes in the retina in diabetes. However, mechanisms regulating miR-200b in diabetes are not known. Histone methyltransferase complex, Polycomb Repressive Complex 2 (PRC2), has been shown to repress miRNAs in neoplastic process. We hypothesized that, in diabetes, PRC2 represses miR-200b through its histone H3 lysine-27 trimethylation mark. We show that human retinal microvascular endothelial cells exposed to high levels of glucose regulate miR-200b repression through histone methylation and that inhibition of PRC2 increases miR-200b while reducing VEGF. Furthermore, retinal tissue from animal models of diabetes showed increased expression of major PRC2 components, demonstrating in vivo relevance. This research established a repressive relationship between PRC2 and miR-200b, providing evidence of a novel mechanism of miRNA regulation through histone methylation.

Show MeSH
Related in: MedlinePlus