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Fisetin and luteolin protect human retinal pigment epithelial cells from oxidative stress-induced cell death and regulate inflammation.

Hytti M, Piippo N, Korhonen E, Honkakoski P, Kaarniranta K, Kauppinen A - Sci Rep (2015)

Bottom Line: Here, we assess the ability of fisetin and luteolin, to protect ARPE-19 cells from oxidative stress-induced cell death and to decrease intracellular inflammation.The decrease in inflammation was associated with reduced activation of MAPKs and CREB, but was not linked to NF- κB or SIRT1.The ability of fisetin and luteolin to protect and repair stressed RPE cells even after the oxidative insult make them attractive in the search for treatments for AMD.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O.B. 1627, FI-70211, Kuopio, Finland.

ABSTRACT
Degeneration of retinal pigment epithelial (RPE) cells is a clinical hallmark of age-related macular degeneration (AMD), the leading cause of blindness among aged people in the Western world. Both inflammation and oxidative stress are known to play vital roles in the development of this disease. Here, we assess the ability of fisetin and luteolin, to protect ARPE-19 cells from oxidative stress-induced cell death and to decrease intracellular inflammation. We also compare the growth and reactivity of human ARPE-19 cells in serum-free and serum-containing conditions. The absence of serum in the culture medium did not prevent ARPE-19 cells from reaching full confluency but caused an increased sensitivity to oxidative stress-induced cell death. Both fisetin and luteolin protected ARPE-19 cells from oxidative stress-induced cell death. They also significantly decreased the release of pro-inflammatory cytokines into the culture medium. The decrease in inflammation was associated with reduced activation of MAPKs and CREB, but was not linked to NF- κB or SIRT1. The ability of fisetin and luteolin to protect and repair stressed RPE cells even after the oxidative insult make them attractive in the search for treatments for AMD.

No MeSH data available.


Related in: MedlinePlus

Effects of specific MAPK inhibitors on cell survival and cytokine release from HNE-treated serum-starved ARPE-19 cells.The JNK inhibitor SP600125 (SP), the MEK1/2 inhibitor PD98059 (PD) and the p38 MAPK inhibitor SB203580 (SB) had no protective effect on the cell viability ((a): MTT assay and (b) LDH assay) of serum-starved ARPE-19 cells stimulated with HNE. Release of the cytokine IL-6 (c) was decreased only by PD, whereas IL-8 (d) levels were reduced by both PD and SP but increased by SB when compared to cells exposed to HNE and the solvent DMSO. Cell viability was normalized to untreated controls while the cytokine levels were compared to HNE + DMSO-exposed positive controls. Addition of HNE + DMSO reduced the release of IL-6 and IL-8 compared to untreated control (Suppl. Fig. 4). Results are shown as scatterplots with median and are combined from 3 independent experiments with 3–4 parallel determinations per group/experiment. *denotes p < 0.05, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.
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f6: Effects of specific MAPK inhibitors on cell survival and cytokine release from HNE-treated serum-starved ARPE-19 cells.The JNK inhibitor SP600125 (SP), the MEK1/2 inhibitor PD98059 (PD) and the p38 MAPK inhibitor SB203580 (SB) had no protective effect on the cell viability ((a): MTT assay and (b) LDH assay) of serum-starved ARPE-19 cells stimulated with HNE. Release of the cytokine IL-6 (c) was decreased only by PD, whereas IL-8 (d) levels were reduced by both PD and SP but increased by SB when compared to cells exposed to HNE and the solvent DMSO. Cell viability was normalized to untreated controls while the cytokine levels were compared to HNE + DMSO-exposed positive controls. Addition of HNE + DMSO reduced the release of IL-6 and IL-8 compared to untreated control (Suppl. Fig. 4). Results are shown as scatterplots with median and are combined from 3 independent experiments with 3–4 parallel determinations per group/experiment. *denotes p < 0.05, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.

Mentions: In order to test the role of the inhibition of MAPK on the release of IL-6 and IL-8 from HNE-treated ARPE-19 cells, we inhibited MAP kinases JNK and p38, as well as MAP kinase kinase MEK1/2 by adding specific MAPK inhibitors 1 hour after the HNE treatment. Inhibition of either of these MAPKs conferred no protective effect on the cellular viability of HNE-treated ARPE-19 cells (Fig. 6a,b). Instead, the inhibition of p38 inhibition seemed to decrease the metabolic activity and compromise the cellular membrane integrity, which was determined using the MTT assay and the LDH assay, respectively (Fig. 6a,b). The inhibition of p38 also resulted in increased IL-8 levels appearing in the medium (Fig. 6d). On the other hand, the inhibition of ERK1/2 by blocking its upstream regulator MEK1/2 decreased the release of both IL-6 and IL-8 (Fig. 6c,d). Furthermore, the inhibition of JNK decreased the levels of IL-8 but exerted no effect on the IL-6 production (Fig. 6c,d). Our present results suggest that JNK and ERK1/2 play important roles in the anti-inflammatory effects of fisetin and luteolin.


Fisetin and luteolin protect human retinal pigment epithelial cells from oxidative stress-induced cell death and regulate inflammation.

Hytti M, Piippo N, Korhonen E, Honkakoski P, Kaarniranta K, Kauppinen A - Sci Rep (2015)

Effects of specific MAPK inhibitors on cell survival and cytokine release from HNE-treated serum-starved ARPE-19 cells.The JNK inhibitor SP600125 (SP), the MEK1/2 inhibitor PD98059 (PD) and the p38 MAPK inhibitor SB203580 (SB) had no protective effect on the cell viability ((a): MTT assay and (b) LDH assay) of serum-starved ARPE-19 cells stimulated with HNE. Release of the cytokine IL-6 (c) was decreased only by PD, whereas IL-8 (d) levels were reduced by both PD and SP but increased by SB when compared to cells exposed to HNE and the solvent DMSO. Cell viability was normalized to untreated controls while the cytokine levels were compared to HNE + DMSO-exposed positive controls. Addition of HNE + DMSO reduced the release of IL-6 and IL-8 compared to untreated control (Suppl. Fig. 4). Results are shown as scatterplots with median and are combined from 3 independent experiments with 3–4 parallel determinations per group/experiment. *denotes p < 0.05, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4664957&req=5

f6: Effects of specific MAPK inhibitors on cell survival and cytokine release from HNE-treated serum-starved ARPE-19 cells.The JNK inhibitor SP600125 (SP), the MEK1/2 inhibitor PD98059 (PD) and the p38 MAPK inhibitor SB203580 (SB) had no protective effect on the cell viability ((a): MTT assay and (b) LDH assay) of serum-starved ARPE-19 cells stimulated with HNE. Release of the cytokine IL-6 (c) was decreased only by PD, whereas IL-8 (d) levels were reduced by both PD and SP but increased by SB when compared to cells exposed to HNE and the solvent DMSO. Cell viability was normalized to untreated controls while the cytokine levels were compared to HNE + DMSO-exposed positive controls. Addition of HNE + DMSO reduced the release of IL-6 and IL-8 compared to untreated control (Suppl. Fig. 4). Results are shown as scatterplots with median and are combined from 3 independent experiments with 3–4 parallel determinations per group/experiment. *denotes p < 0.05, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.
Mentions: In order to test the role of the inhibition of MAPK on the release of IL-6 and IL-8 from HNE-treated ARPE-19 cells, we inhibited MAP kinases JNK and p38, as well as MAP kinase kinase MEK1/2 by adding specific MAPK inhibitors 1 hour after the HNE treatment. Inhibition of either of these MAPKs conferred no protective effect on the cellular viability of HNE-treated ARPE-19 cells (Fig. 6a,b). Instead, the inhibition of p38 inhibition seemed to decrease the metabolic activity and compromise the cellular membrane integrity, which was determined using the MTT assay and the LDH assay, respectively (Fig. 6a,b). The inhibition of p38 also resulted in increased IL-8 levels appearing in the medium (Fig. 6d). On the other hand, the inhibition of ERK1/2 by blocking its upstream regulator MEK1/2 decreased the release of both IL-6 and IL-8 (Fig. 6c,d). Furthermore, the inhibition of JNK decreased the levels of IL-8 but exerted no effect on the IL-6 production (Fig. 6c,d). Our present results suggest that JNK and ERK1/2 play important roles in the anti-inflammatory effects of fisetin and luteolin.

Bottom Line: Here, we assess the ability of fisetin and luteolin, to protect ARPE-19 cells from oxidative stress-induced cell death and to decrease intracellular inflammation.The decrease in inflammation was associated with reduced activation of MAPKs and CREB, but was not linked to NF- κB or SIRT1.The ability of fisetin and luteolin to protect and repair stressed RPE cells even after the oxidative insult make them attractive in the search for treatments for AMD.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O.B. 1627, FI-70211, Kuopio, Finland.

ABSTRACT
Degeneration of retinal pigment epithelial (RPE) cells is a clinical hallmark of age-related macular degeneration (AMD), the leading cause of blindness among aged people in the Western world. Both inflammation and oxidative stress are known to play vital roles in the development of this disease. Here, we assess the ability of fisetin and luteolin, to protect ARPE-19 cells from oxidative stress-induced cell death and to decrease intracellular inflammation. We also compare the growth and reactivity of human ARPE-19 cells in serum-free and serum-containing conditions. The absence of serum in the culture medium did not prevent ARPE-19 cells from reaching full confluency but caused an increased sensitivity to oxidative stress-induced cell death. Both fisetin and luteolin protected ARPE-19 cells from oxidative stress-induced cell death. They also significantly decreased the release of pro-inflammatory cytokines into the culture medium. The decrease in inflammation was associated with reduced activation of MAPKs and CREB, but was not linked to NF- κB or SIRT1. The ability of fisetin and luteolin to protect and repair stressed RPE cells even after the oxidative insult make them attractive in the search for treatments for AMD.

No MeSH data available.


Related in: MedlinePlus