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The impact of polyphenols on chondrocyte growth and survival: a preliminary report.

Fernández-Arroyo S, Huete-Toral F, Pérez de Lara MJ, de la Luz Cádiz-Gurrea M, Legeai-Mallet L, Micol V, Segura-Carretero A, Joven J, Pintor J - Food Nutr Res (2015)

Bottom Line: We explored the possible effects of polyphenols in the management of osteoarticular diseases using a model based on the transduction of a mutated human FGFR3 (G380R) in murine chondrocytes.The inhibition of mitogen-activated protein kinase phosphorylation was interpreted as the main mechanism governing these beneficial effects.These findings support the rationale behind the encouragement of the development of drugs that repress the overexpression of FGFRs and suggest the dietary incorporation of supplementary nutrients in the management of degraded cartilage.

View Article: PubMed Central - PubMed

Affiliation: Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, IISPV, Universitat Rovira i Virgili, Reus, Spain.

ABSTRACT

Background: Imbalances in the functional binding of fibroblast growth factors (FGFs) to their receptors (FGFRs) have consequences for cell proliferation and differentiation that in chondrocytes may lead to degraded cartilage. The toxic, proinflammatory, and oxidative response of cytokines and FGFs can be mitigated by dietary polyphenols.

Objective: We explored the possible effects of polyphenols in the management of osteoarticular diseases using a model based on the transduction of a mutated human FGFR3 (G380R) in murine chondrocytes. This mutation is present in most cases of skeletal dysplasia and is responsible for the overexpression of FGFR3 that, in the presence of its ligand, FGF9, results in toxic effects leading to altered cellular growth.

Design: Different combinations of dietary polyphenols derived from plant extracts were assayed in FGFR3 (G380R) mutated murine chondrocytes, exploring cell survival, chloride efflux, extracellular matrix (ECM) generation, and grade of activation of mitogen-activated protein kinases.

Results: Bioactive compounds from Hibiscus sabdariffa reversed the toxic effects of FGF9 and restored normal growth, suggesting a probable translation to clinical requests in humans. Indeed, these compounds activated the intracellular chloride efflux, increased ECM generation, and stimulated cell proliferation. The inhibition of mitogen-activated protein kinase phosphorylation was interpreted as the main mechanism governing these beneficial effects.

Conclusions: These findings support the rationale behind the encouragement of the development of drugs that repress the overexpression of FGFRs and suggest the dietary incorporation of supplementary nutrients in the management of degraded cartilage.

No MeSH data available.


Related in: MedlinePlus

Relative ERK-1/-2 phosphorylation. Experiments were performed in FGFR3 (G380R) mutant RCJ3.1C5.18 chondrocytes with or without FGF9 (25 ng/mL) and further incubated with Hibiscus sabdariffa or its polyphenolic extract. Data were combined and expressed as the mean±SD (n=6, in triplicate). Representative results were included for illustrative purposes.
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Figure 0002: Relative ERK-1/-2 phosphorylation. Experiments were performed in FGFR3 (G380R) mutant RCJ3.1C5.18 chondrocytes with or without FGF9 (25 ng/mL) and further incubated with Hibiscus sabdariffa or its polyphenolic extract. Data were combined and expressed as the mean±SD (n=6, in triplicate). Representative results were included for illustrative purposes.

Mentions: The expression in chondrocytes of the FGFR3 (G380R) mutation is currently considered to be the likely cause of the human chondrodysplasia, termed achondroplasia (40, 41). In these patients, there is an over-activation of FGFR3 in the presence of FGF9, which results in toxic effects in chondrocytes, preventing endochondral bone formation. Because this represents a gain-of-function mutation and FGFR3 is a transmembrane receptor tyrosine kinase that initiates signal transduction to the nucleus, it is reasonable to predict that successful therapeutic strategies would decrease or eliminate FGFR3 signals. Using mouse chondrocytes containing the human mutant FGFR3, it has been possible to test the effects of polyphenols and how these and other plant dietary compounds affect intracellular signaling networks in an achondroplastic model (2). To follow this approach, we measured the effect of commercially available extracts commonly used in edible preparations on the modulation of chloride efflux by FGFR3 (G380R) and FGF9. The arrangement of FGF9 and FGFR3 in this model induced an enlarged achondroplastic chondrocyte size and an increase in the intracellular chloride, which is likely the result of an inhibition of the chloride efflux (42). Intriguingly, most polyphenol combinations further increased the intracellular chloride concentration and potentiated the deleterious effects in chondrocytes (Fig. 1a). Quantitative effects, however, differed considerably, and we noted significant changes in cell size and a disproportionate 15-fold increase in intracellular chloride concentration caused by C. aurantium. In response to the reproducibility of these data, we excluded these dietary extracts in this study, but this information will drive studies to further investigate the role of resting membrane potential in the normal development of chondrocytes. Conversely, compounds from H. sabdariffa restrained the increase in the intracellular chloride concentration (Fig. 1b). Interpretation is difficult because data could indicate combined actions on FGFR3 signaling, binding of FGF9, or direct preservation of the membrane potential. Furthermore, analysis of the composition of the complex mixture of compounds in the initial extract revealed that a significant amount of organic acids and other materials were present together with polyphenols. We then eliminated these residual components to obtain an extract in which polyphenols were concentrated. Subsequent experiments, once corrected for the total amount of compounds, indicated that the effect of polyphenols in the regulation of chloride efflux, although significant, was less intense than that observed in the initial extract (Fig. 1b and Supplementary Tables 1 and 2). Contrary to what we expected, the results suggest a major role for organic acids, particularly hydroxycitric acid, but attribution of the effect to a single component is highly unlikely. Moreover, when we utilized both mixtures derived from H. sabdariffa, polyphenols appeared to be the compounds causing the inhibition of ERK-1/-2 (p42 and p44) phosphorylation. ERKs are important in cellular growth and development (17, 43–48), and the effects were detectable in cultures without FGF9, but statistical significance was only achieved in the presence of the ligand (Fig. 2). This effect is relevant because ERK-1/-2 phosphorylation was activated in FGFR3 (G380R) chondrocytes challenged with FGF9, confirming our previous findings (28). The role of the original H. sabdariffa extract may not be inferred from our data because it had no significant effect on the level of phosphorylation with or without FGF9, but it has been shown to target other multiple components (49–54). However, we limited the exploration to the MAPK pathway because ERK-1/-2 inhibition under these conditions is probably restricted to chondrocytes, in which this signaling system regulates cell growth, proliferation, and ECM accumulation (55–62).


The impact of polyphenols on chondrocyte growth and survival: a preliminary report.

Fernández-Arroyo S, Huete-Toral F, Pérez de Lara MJ, de la Luz Cádiz-Gurrea M, Legeai-Mallet L, Micol V, Segura-Carretero A, Joven J, Pintor J - Food Nutr Res (2015)

Relative ERK-1/-2 phosphorylation. Experiments were performed in FGFR3 (G380R) mutant RCJ3.1C5.18 chondrocytes with or without FGF9 (25 ng/mL) and further incubated with Hibiscus sabdariffa or its polyphenolic extract. Data were combined and expressed as the mean±SD (n=6, in triplicate). Representative results were included for illustrative purposes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595466&req=5

Figure 0002: Relative ERK-1/-2 phosphorylation. Experiments were performed in FGFR3 (G380R) mutant RCJ3.1C5.18 chondrocytes with or without FGF9 (25 ng/mL) and further incubated with Hibiscus sabdariffa or its polyphenolic extract. Data were combined and expressed as the mean±SD (n=6, in triplicate). Representative results were included for illustrative purposes.
Mentions: The expression in chondrocytes of the FGFR3 (G380R) mutation is currently considered to be the likely cause of the human chondrodysplasia, termed achondroplasia (40, 41). In these patients, there is an over-activation of FGFR3 in the presence of FGF9, which results in toxic effects in chondrocytes, preventing endochondral bone formation. Because this represents a gain-of-function mutation and FGFR3 is a transmembrane receptor tyrosine kinase that initiates signal transduction to the nucleus, it is reasonable to predict that successful therapeutic strategies would decrease or eliminate FGFR3 signals. Using mouse chondrocytes containing the human mutant FGFR3, it has been possible to test the effects of polyphenols and how these and other plant dietary compounds affect intracellular signaling networks in an achondroplastic model (2). To follow this approach, we measured the effect of commercially available extracts commonly used in edible preparations on the modulation of chloride efflux by FGFR3 (G380R) and FGF9. The arrangement of FGF9 and FGFR3 in this model induced an enlarged achondroplastic chondrocyte size and an increase in the intracellular chloride, which is likely the result of an inhibition of the chloride efflux (42). Intriguingly, most polyphenol combinations further increased the intracellular chloride concentration and potentiated the deleterious effects in chondrocytes (Fig. 1a). Quantitative effects, however, differed considerably, and we noted significant changes in cell size and a disproportionate 15-fold increase in intracellular chloride concentration caused by C. aurantium. In response to the reproducibility of these data, we excluded these dietary extracts in this study, but this information will drive studies to further investigate the role of resting membrane potential in the normal development of chondrocytes. Conversely, compounds from H. sabdariffa restrained the increase in the intracellular chloride concentration (Fig. 1b). Interpretation is difficult because data could indicate combined actions on FGFR3 signaling, binding of FGF9, or direct preservation of the membrane potential. Furthermore, analysis of the composition of the complex mixture of compounds in the initial extract revealed that a significant amount of organic acids and other materials were present together with polyphenols. We then eliminated these residual components to obtain an extract in which polyphenols were concentrated. Subsequent experiments, once corrected for the total amount of compounds, indicated that the effect of polyphenols in the regulation of chloride efflux, although significant, was less intense than that observed in the initial extract (Fig. 1b and Supplementary Tables 1 and 2). Contrary to what we expected, the results suggest a major role for organic acids, particularly hydroxycitric acid, but attribution of the effect to a single component is highly unlikely. Moreover, when we utilized both mixtures derived from H. sabdariffa, polyphenols appeared to be the compounds causing the inhibition of ERK-1/-2 (p42 and p44) phosphorylation. ERKs are important in cellular growth and development (17, 43–48), and the effects were detectable in cultures without FGF9, but statistical significance was only achieved in the presence of the ligand (Fig. 2). This effect is relevant because ERK-1/-2 phosphorylation was activated in FGFR3 (G380R) chondrocytes challenged with FGF9, confirming our previous findings (28). The role of the original H. sabdariffa extract may not be inferred from our data because it had no significant effect on the level of phosphorylation with or without FGF9, but it has been shown to target other multiple components (49–54). However, we limited the exploration to the MAPK pathway because ERK-1/-2 inhibition under these conditions is probably restricted to chondrocytes, in which this signaling system regulates cell growth, proliferation, and ECM accumulation (55–62).

Bottom Line: We explored the possible effects of polyphenols in the management of osteoarticular diseases using a model based on the transduction of a mutated human FGFR3 (G380R) in murine chondrocytes.The inhibition of mitogen-activated protein kinase phosphorylation was interpreted as the main mechanism governing these beneficial effects.These findings support the rationale behind the encouragement of the development of drugs that repress the overexpression of FGFRs and suggest the dietary incorporation of supplementary nutrients in the management of degraded cartilage.

View Article: PubMed Central - PubMed

Affiliation: Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, IISPV, Universitat Rovira i Virgili, Reus, Spain.

ABSTRACT

Background: Imbalances in the functional binding of fibroblast growth factors (FGFs) to their receptors (FGFRs) have consequences for cell proliferation and differentiation that in chondrocytes may lead to degraded cartilage. The toxic, proinflammatory, and oxidative response of cytokines and FGFs can be mitigated by dietary polyphenols.

Objective: We explored the possible effects of polyphenols in the management of osteoarticular diseases using a model based on the transduction of a mutated human FGFR3 (G380R) in murine chondrocytes. This mutation is present in most cases of skeletal dysplasia and is responsible for the overexpression of FGFR3 that, in the presence of its ligand, FGF9, results in toxic effects leading to altered cellular growth.

Design: Different combinations of dietary polyphenols derived from plant extracts were assayed in FGFR3 (G380R) mutated murine chondrocytes, exploring cell survival, chloride efflux, extracellular matrix (ECM) generation, and grade of activation of mitogen-activated protein kinases.

Results: Bioactive compounds from Hibiscus sabdariffa reversed the toxic effects of FGF9 and restored normal growth, suggesting a probable translation to clinical requests in humans. Indeed, these compounds activated the intracellular chloride efflux, increased ECM generation, and stimulated cell proliferation. The inhibition of mitogen-activated protein kinase phosphorylation was interpreted as the main mechanism governing these beneficial effects.

Conclusions: These findings support the rationale behind the encouragement of the development of drugs that repress the overexpression of FGFRs and suggest the dietary incorporation of supplementary nutrients in the management of degraded cartilage.

No MeSH data available.


Related in: MedlinePlus