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The effects of pleiotrophin in proliferative diabetic retinopathy.

Zhu X, Bai Y, Yu W, Pan C, Jin E, Song D, Xu Q, Yao Y, Huang L, Tao Y, Li X, Zhao M - PLoS ONE (2015)

Bottom Line: However, little is known about its effects on diabetic retinopathy, a neurovascular disease.Mechanically, PTN depletion decreased ERK 1/2 phosphorylation.Taken together, our results implied that elevated PTN in PDR patients might participate in the critical processes of the development of PDR, most likely playing roles in angiogenesis and proliferation, possibly by activating the ERK 1/2 pathway and regulating VEGF secretion.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Peking University People's Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, 100044, China.

ABSTRACT
Pleiotrophin (PTN), a secreted, multifunctional cytokine, is involved in angiogenic, fibrotic and neurodegenerative diseases. However, little is known about its effects on diabetic retinopathy, a neurovascular disease. To investigate the role of PTN in proliferative diabetic retinopathy (PDR), PTN concentration in the vitreous was evaluated in PDR patients and non-diabetic controls. PTN expression was observed in epiretinal membranes from patients. PTN knockdown was performed using small interfering (si)RNA, and the effects on retinal pigment epithelium (RPE) cells and human umbilical vascular endothelia cells (HUVECs) were observed in vitro under hyperglycemic and hypoxic conditions. Cell attachment, proliferation, migration, tube formation, cell cycle, apoptosis, extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation, and VEGF levels were studied. The vitreous PTN concentration in PDR patients was higher than that in non-diabetic controls, and PTN was highly expressed in the fibrovascular membranes of PDR patients. Under hyperglycemic and hypoxic conditions, PTN knockdown reduced cell attachment, proliferation, migration, and tube formation and induced cell cycle arrest and apoptosis in vitro. Mechanically, PTN depletion decreased ERK 1/2 phosphorylation. Recombinant PTN up regulated the concentration of VEGF in vitro, which can be attenuated by the ERK 1/2 inhibitor. Taken together, our results implied that elevated PTN in PDR patients might participate in the critical processes of the development of PDR, most likely playing roles in angiogenesis and proliferation, possibly by activating the ERK 1/2 pathway and regulating VEGF secretion. These findings provide new insight into the roles of PTN in PDR and suggest that PTN may become a new target for therapeutic intervention in PDR.

No MeSH data available.


Related in: MedlinePlus

Effect of PTN-siRNA on RPE cells and HUVECs.PTN expression in human RPE cells and HUVECs was significantly knocked down in PTN-siRNA treated groups at the mRNA level, as measured by real-time RT-PCR 48 h after transfection. There’s no difference in NC and NS groups. The expression of NC was set to 100%. Data are expressed as the means ± SD of results from at least three independent experiments (**P < 0.01).
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pone.0115523.g003: Effect of PTN-siRNA on RPE cells and HUVECs.PTN expression in human RPE cells and HUVECs was significantly knocked down in PTN-siRNA treated groups at the mRNA level, as measured by real-time RT-PCR 48 h after transfection. There’s no difference in NC and NS groups. The expression of NC was set to 100%. Data are expressed as the means ± SD of results from at least three independent experiments (**P < 0.01).

Mentions: The effectiveness of PTN-siRNA transfection into RPE cells and HUVECs was determined by real-time RT-PCR and cell immunofluorescence. RT-PCR demonstrated that PTN-siRNA specifically reduced PTN mRNA levels in RPE cells and HUVECs (P < 0.01; Fig. 3). There was no significant difference between the non-silencing-siRNA-treated group (NS) and normal control (NC) cells (P > 0.05). Immunocytochemical imaging of PTN expression in cells further confirmed PTN knockdown (Fig. 4). The fluorescence intensity representing PTN expression in NC (Fig. 4A, 4B) and NS (Fig. 4C, 4D) was very strong, but the expression level in PTN-siRNA-transfected cells (Fig. 4E, 4F) was barely detectable. These results demonstrated that we successfully generated specific knockdown reagents that selectively target PTN in RPE cells and HUVECs.


The effects of pleiotrophin in proliferative diabetic retinopathy.

Zhu X, Bai Y, Yu W, Pan C, Jin E, Song D, Xu Q, Yao Y, Huang L, Tao Y, Li X, Zhao M - PLoS ONE (2015)

Effect of PTN-siRNA on RPE cells and HUVECs.PTN expression in human RPE cells and HUVECs was significantly knocked down in PTN-siRNA treated groups at the mRNA level, as measured by real-time RT-PCR 48 h after transfection. There’s no difference in NC and NS groups. The expression of NC was set to 100%. Data are expressed as the means ± SD of results from at least three independent experiments (**P < 0.01).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4305314&req=5

pone.0115523.g003: Effect of PTN-siRNA on RPE cells and HUVECs.PTN expression in human RPE cells and HUVECs was significantly knocked down in PTN-siRNA treated groups at the mRNA level, as measured by real-time RT-PCR 48 h after transfection. There’s no difference in NC and NS groups. The expression of NC was set to 100%. Data are expressed as the means ± SD of results from at least three independent experiments (**P < 0.01).
Mentions: The effectiveness of PTN-siRNA transfection into RPE cells and HUVECs was determined by real-time RT-PCR and cell immunofluorescence. RT-PCR demonstrated that PTN-siRNA specifically reduced PTN mRNA levels in RPE cells and HUVECs (P < 0.01; Fig. 3). There was no significant difference between the non-silencing-siRNA-treated group (NS) and normal control (NC) cells (P > 0.05). Immunocytochemical imaging of PTN expression in cells further confirmed PTN knockdown (Fig. 4). The fluorescence intensity representing PTN expression in NC (Fig. 4A, 4B) and NS (Fig. 4C, 4D) was very strong, but the expression level in PTN-siRNA-transfected cells (Fig. 4E, 4F) was barely detectable. These results demonstrated that we successfully generated specific knockdown reagents that selectively target PTN in RPE cells and HUVECs.

Bottom Line: However, little is known about its effects on diabetic retinopathy, a neurovascular disease.Mechanically, PTN depletion decreased ERK 1/2 phosphorylation.Taken together, our results implied that elevated PTN in PDR patients might participate in the critical processes of the development of PDR, most likely playing roles in angiogenesis and proliferation, possibly by activating the ERK 1/2 pathway and regulating VEGF secretion.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Peking University People's Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, 100044, China.

ABSTRACT
Pleiotrophin (PTN), a secreted, multifunctional cytokine, is involved in angiogenic, fibrotic and neurodegenerative diseases. However, little is known about its effects on diabetic retinopathy, a neurovascular disease. To investigate the role of PTN in proliferative diabetic retinopathy (PDR), PTN concentration in the vitreous was evaluated in PDR patients and non-diabetic controls. PTN expression was observed in epiretinal membranes from patients. PTN knockdown was performed using small interfering (si)RNA, and the effects on retinal pigment epithelium (RPE) cells and human umbilical vascular endothelia cells (HUVECs) were observed in vitro under hyperglycemic and hypoxic conditions. Cell attachment, proliferation, migration, tube formation, cell cycle, apoptosis, extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation, and VEGF levels were studied. The vitreous PTN concentration in PDR patients was higher than that in non-diabetic controls, and PTN was highly expressed in the fibrovascular membranes of PDR patients. Under hyperglycemic and hypoxic conditions, PTN knockdown reduced cell attachment, proliferation, migration, and tube formation and induced cell cycle arrest and apoptosis in vitro. Mechanically, PTN depletion decreased ERK 1/2 phosphorylation. Recombinant PTN up regulated the concentration of VEGF in vitro, which can be attenuated by the ERK 1/2 inhibitor. Taken together, our results implied that elevated PTN in PDR patients might participate in the critical processes of the development of PDR, most likely playing roles in angiogenesis and proliferation, possibly by activating the ERK 1/2 pathway and regulating VEGF secretion. These findings provide new insight into the roles of PTN in PDR and suggest that PTN may become a new target for therapeutic intervention in PDR.

No MeSH data available.


Related in: MedlinePlus