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The epigenetic effect of glucosamine and a nuclear factor-kappa B (NF-kB) inhibitor on primary human chondrocytes-implications for osteoarthritis

The epigenetic effect of glucosamine and a nuclear factor-kappa B (NF-kB) inhibitor on primary human chondrocytes-implications for osteoarthritis
The epigenetic effect of glucosamine and a nuclear factor-kappa B (NF-kB) inhibitor on primary human chondrocytes-implications for osteoarthritis
Objective: Idiopathic osteoarthritis is the most common form of osteoarthritis (OA) world-wide and remains the leading cause of disability and the associated socio-economic burden in an increasing aging population. Traditionally, OA has been viewed as a degenerative joint disease characterized by progressive destruction of the articular cartilage and changes in the subchondral bone culminating in joint failure. However, the etiology of OA is multifactorial involving genetic, mechanical and environmental factors. Treatment modalities include analgesia, joint injection with steroids or hyaluronic acid, oral supplements including glucosamine and chondroitin sulfate, as well as physiotherapy. Thus, there is significant interest in the discovery of disease modifying agents. One such agent, glucosamine (GlcN) is commonly prescribed even though the therapeutic efficacy and mechanism of action remain controversial. Inflammatory cytokines, including IL-1b, and proteinases such as MMP-13 have been implicated in the pathogenesis and progression of OA together with an associated CpG demethylation in their promoters. We have investigated the potential of GlcN to modulate NF-kB activity and cytokine-induced abnormal gene expression in articular chondrocytes and, critically, whether this is associated with an epigenetic process.

Method: Human chondrocytes were isolated from the articular cartilage of femoral heads, obtained with ethical permission, following fractured neck of femur surgery. Chondrocytes were cultured for 5 weeks in six separate groups; (i) control culture, (ii) cultured with a mixture of 2.5 ng/ml IL-1b and 2.5 ng/ml oncostatin M (OSM), (iii) cultured with 2 mM N-acetyl GlcN (Sigma–Aldrich),(iv) cultured with a mixture of 2.5 ng/ml IL-1b, 2.5 ng/ml OSM and 2 mM GlcN, (v) cultured with 1.0 lM BAY 11-7082 (BAY; NF-kB inhibitor: Calbiochem, Darmstadt, Germany) and, (vi) cultured with a mixture of 2.5 ng/ml IL-1b, 2.5 ng/ml OSM and 1.0 lM BAY. The levels of IL1B and MMP13 mRNA were examined using qRT-PCR. The percentage DNA methylation in the CpG sites of the IL1b and MMP13 proximal promoter were quantified by pyrosequencing. Result: IL1b expression was enhanced over 580-fold in articular chondrocytes treated with IL-1b and OSM. GlcN dramatically ameliorated the cytokine-induced expression by 4-fold. BAY alone increased IL1b expression by 3-fold. In the presence of BAY, IL-1b induced IL1B mRNA levels were decreased by 6-fold. The observed average percentage methylation of the -256 CpG site in the IL1b promoter was 65% in control cultures and decreased to 36% in the presence of IL-1b/OSM. GlcN and BAY alone had a negligible effect on the methylation status of the IL1B promoter. The cytokine-induced loss of methylation status in the IL1B promoter was ameliorated by both GlcN and BAY to 44% and 53%, respectively. IL-1b/OSM treatment increased MMP13 mRNA levels independently of either GlcN or BAY and no change in the methylation status of the MMP13 promoter was observed.

Conclusion: We demonstrate for the first time that GlcN and BAY can prevent cytokine-induced demethylation of a specific CpG site in the IL1b promoter and this was associated with decreased expression of IL1b. These studies provide a potential mechanism of action for OA disease modifying agents via NF-kB and, critically, demonstrate the need for further studies to elucidate the role that NF-kB may play in DNA demethylation in human chondrocytes.
osteoarthritis, chondrocytes, glucosamine, NF-kB, IL1B
0006-291X
362-367
Imagawa, Kei
cfdeef65-8259-4f0c-943a-0d439aab3193
de Andres, M. C.
e6483445-efc7-444b-9f1d-164c8705fc82
Hashimoto, Ko
19b8f3be-d539-4579-a6cb-936ed0243b27
Pitt, Dominic
7a545c0b-e326-4d98-9ff3-36b7e8d14bd6
Itobi, Eiji
f149131b-9ca4-4176-b5f0-6a88ebdbf655
Goldring, Mary B.
67cbd000-e36a-4b82-bc50-f3c5a8d292da
Roach, Helmtrud I.
ca2ff1f4-1ada-4c56-9097-cd27ca4d199e
Oreffo, Richard O.C.
ff9fff72-6855-4d0f-bfb2-311d0e8f3778
Imagawa, Kei
cfdeef65-8259-4f0c-943a-0d439aab3193
de Andres, M. C.
e6483445-efc7-444b-9f1d-164c8705fc82
Hashimoto, Ko
19b8f3be-d539-4579-a6cb-936ed0243b27
Pitt, Dominic
7a545c0b-e326-4d98-9ff3-36b7e8d14bd6
Itobi, Eiji
f149131b-9ca4-4176-b5f0-6a88ebdbf655
Goldring, Mary B.
67cbd000-e36a-4b82-bc50-f3c5a8d292da
Roach, Helmtrud I.
ca2ff1f4-1ada-4c56-9097-cd27ca4d199e
Oreffo, Richard O.C.
ff9fff72-6855-4d0f-bfb2-311d0e8f3778

Imagawa, Kei, de Andres, M. C., Hashimoto, Ko, Pitt, Dominic, Itobi, Eiji, Goldring, Mary B., Roach, Helmtrud I. and Oreffo, Richard O.C. (2011) The epigenetic effect of glucosamine and a nuclear factor-kappa B (NF-kB) inhibitor on primary human chondrocytes-implications for osteoarthritis. Biochemical and Biophysical Research Communications, 405 (3), 362-367. (doi:10.1016/j.bbrc.2011.01.007). (PMID:21219853) (Submitted)

Record type: Article

Abstract

Objective: Idiopathic osteoarthritis is the most common form of osteoarthritis (OA) world-wide and remains the leading cause of disability and the associated socio-economic burden in an increasing aging population. Traditionally, OA has been viewed as a degenerative joint disease characterized by progressive destruction of the articular cartilage and changes in the subchondral bone culminating in joint failure. However, the etiology of OA is multifactorial involving genetic, mechanical and environmental factors. Treatment modalities include analgesia, joint injection with steroids or hyaluronic acid, oral supplements including glucosamine and chondroitin sulfate, as well as physiotherapy. Thus, there is significant interest in the discovery of disease modifying agents. One such agent, glucosamine (GlcN) is commonly prescribed even though the therapeutic efficacy and mechanism of action remain controversial. Inflammatory cytokines, including IL-1b, and proteinases such as MMP-13 have been implicated in the pathogenesis and progression of OA together with an associated CpG demethylation in their promoters. We have investigated the potential of GlcN to modulate NF-kB activity and cytokine-induced abnormal gene expression in articular chondrocytes and, critically, whether this is associated with an epigenetic process.

Method: Human chondrocytes were isolated from the articular cartilage of femoral heads, obtained with ethical permission, following fractured neck of femur surgery. Chondrocytes were cultured for 5 weeks in six separate groups; (i) control culture, (ii) cultured with a mixture of 2.5 ng/ml IL-1b and 2.5 ng/ml oncostatin M (OSM), (iii) cultured with 2 mM N-acetyl GlcN (Sigma–Aldrich),(iv) cultured with a mixture of 2.5 ng/ml IL-1b, 2.5 ng/ml OSM and 2 mM GlcN, (v) cultured with 1.0 lM BAY 11-7082 (BAY; NF-kB inhibitor: Calbiochem, Darmstadt, Germany) and, (vi) cultured with a mixture of 2.5 ng/ml IL-1b, 2.5 ng/ml OSM and 1.0 lM BAY. The levels of IL1B and MMP13 mRNA were examined using qRT-PCR. The percentage DNA methylation in the CpG sites of the IL1b and MMP13 proximal promoter were quantified by pyrosequencing. Result: IL1b expression was enhanced over 580-fold in articular chondrocytes treated with IL-1b and OSM. GlcN dramatically ameliorated the cytokine-induced expression by 4-fold. BAY alone increased IL1b expression by 3-fold. In the presence of BAY, IL-1b induced IL1B mRNA levels were decreased by 6-fold. The observed average percentage methylation of the -256 CpG site in the IL1b promoter was 65% in control cultures and decreased to 36% in the presence of IL-1b/OSM. GlcN and BAY alone had a negligible effect on the methylation status of the IL1B promoter. The cytokine-induced loss of methylation status in the IL1B promoter was ameliorated by both GlcN and BAY to 44% and 53%, respectively. IL-1b/OSM treatment increased MMP13 mRNA levels independently of either GlcN or BAY and no change in the methylation status of the MMP13 promoter was observed.

Conclusion: We demonstrate for the first time that GlcN and BAY can prevent cytokine-induced demethylation of a specific CpG site in the IL1b promoter and this was associated with decreased expression of IL1b. These studies provide a potential mechanism of action for OA disease modifying agents via NF-kB and, critically, demonstrate the need for further studies to elucidate the role that NF-kB may play in DNA demethylation in human chondrocytes.

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More information

Submitted date: February 2011
Keywords: osteoarthritis, chondrocytes, glucosamine, NF-kB, IL1B

Identifiers

Local EPrints ID: 181641
URI: http://eprints.soton.ac.uk/id/eprint/181641
ISSN: 0006-291X
PURE UUID: dd4dc8a2-557a-4ba1-9194-49a191e435b6
ORCID for Richard O.C. Oreffo: ORCID iD orcid.org/0000-0001-5995-6726

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Date deposited: 15 Apr 2011 09:15
Last modified: 15 Mar 2024 03:03

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Contributors

Author: Kei Imagawa
Author: M. C. de Andres
Author: Ko Hashimoto
Author: Dominic Pitt
Author: Eiji Itobi
Author: Mary B. Goldring
Author: Helmtrud I. Roach

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