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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

Effect of fisetin or luteolin on signaling pathway proteins.Both fisetin and luteolin reduced the phosphorylation of CREB (a), p38 MAPK (b), ERK1/2 (c), and JNK (d), but not that of MEK1/2 (e) or the DNA-binding activity of NF-κB subunit p65 (f) when compared to cells treated with HNE and DMSO. Results are shown as scatterplots with median and are combined from 3-8 independent experiments with 4 parallel determinations per group/experiment. *denotes p < 0.05, **denotes p < 0.01, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.
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f5: Effect of fisetin or luteolin on signaling pathway proteins.Both fisetin and luteolin reduced the phosphorylation of CREB (a), p38 MAPK (b), ERK1/2 (c), and JNK (d), but not that of MEK1/2 (e) or the DNA-binding activity of NF-κB subunit p65 (f) when compared to cells treated with HNE and DMSO. Results are shown as scatterplots with median and are combined from 3-8 independent experiments with 4 parallel determinations per group/experiment. *denotes p < 0.05, **denotes p < 0.01, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.

Mentions: Next, we determined the pathways by which fisetin and luteolin were interfering with the production of pro-inflammatory cytokines by measuring the effects of these compounds on the activity of MAP kinases (p38 MAPK, ERK1/2, JNK), and the transcription factors CREB and NF-κB in HNE-treated ARPE-19 cells. Our results show that 4 hours after the fisetin or luteolin treatment, the phosphorylation levels of transcription factor CREB and the MAPKs p38 MAPK, JNK, and ERK1/2 were markedly decreased when compared to cells treated only with HNE and the solvent DMSO (Fig. 5a–d). HNE + DMSO treatment alone increased the levels of phosphorylated CREB, p38 MAPK, and JNK (Fig. 5a,b,d). The phosphorylation level of MEK1/2, the MAP kinase kinase responsible for the ERK1/2 activation, was not statistically significantly affected by HNE exposure, though a slight, statistically non-significant decrease was observed after the treatment with the polyphenols (Fig. 5e, p = 0.141 for fisetin, p = 0.0885 for luteolin). HNE also decreased the binding activity of the NF-κB subunit p65 to its target DNA sequence. Fisetin and luteolin treatments, however, had no additional effect on the DNA-binding activity of p65, suggesting that inhibition of NF-κB is not the main pathway mediating the decrease in the levels of pro-inflammatory cytokines in ARPE-19 cells treated with fisetin or luteolin (Fig. 5f).


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)

Effect of fisetin or luteolin on signaling pathway proteins.Both fisetin and luteolin reduced the phosphorylation of CREB (a), p38 MAPK (b), ERK1/2 (c), and JNK (d), but not that of MEK1/2 (e) or the DNA-binding activity of NF-κB subunit p65 (f) when compared to cells treated with HNE and DMSO. Results are shown as scatterplots with median and are combined from 3-8 independent experiments with 4 parallel determinations per group/experiment. *denotes p < 0.05, **denotes p < 0.01, ***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

f5: Effect of fisetin or luteolin on signaling pathway proteins.Both fisetin and luteolin reduced the phosphorylation of CREB (a), p38 MAPK (b), ERK1/2 (c), and JNK (d), but not that of MEK1/2 (e) or the DNA-binding activity of NF-κB subunit p65 (f) when compared to cells treated with HNE and DMSO. Results are shown as scatterplots with median and are combined from 3-8 independent experiments with 4 parallel determinations per group/experiment. *denotes p < 0.05, **denotes p < 0.01, ***denotes p < 0.001, ns denotes not statistically significant, Mann–Whitney U-test.
Mentions: Next, we determined the pathways by which fisetin and luteolin were interfering with the production of pro-inflammatory cytokines by measuring the effects of these compounds on the activity of MAP kinases (p38 MAPK, ERK1/2, JNK), and the transcription factors CREB and NF-κB in HNE-treated ARPE-19 cells. Our results show that 4 hours after the fisetin or luteolin treatment, the phosphorylation levels of transcription factor CREB and the MAPKs p38 MAPK, JNK, and ERK1/2 were markedly decreased when compared to cells treated only with HNE and the solvent DMSO (Fig. 5a–d). HNE + DMSO treatment alone increased the levels of phosphorylated CREB, p38 MAPK, and JNK (Fig. 5a,b,d). The phosphorylation level of MEK1/2, the MAP kinase kinase responsible for the ERK1/2 activation, was not statistically significantly affected by HNE exposure, though a slight, statistically non-significant decrease was observed after the treatment with the polyphenols (Fig. 5e, p = 0.141 for fisetin, p = 0.0885 for luteolin). HNE also decreased the binding activity of the NF-κB subunit p65 to its target DNA sequence. Fisetin and luteolin treatments, however, had no additional effect on the DNA-binding activity of p65, suggesting that inhibition of NF-κB is not the main pathway mediating the decrease in the levels of pro-inflammatory cytokines in ARPE-19 cells treated with fisetin or luteolin (Fig. 5f).

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