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Characterization of NF-kB-mediated inhibition of catechol-O-methyltransferase.

Tchivileva IE, Nackley AG, Qian L, Wentworth S, Conrad M, Diatchenko LB - Mol Pain (2009)

Bottom Line: Specifically, low COMT activity is associated with heightened pain perception and development of musculoskeletal pain in humans as well as increased experimental pain sensitivity in rodents.Examination of the distal COMT promoter (P2-COMT) reveals a putative binding site for nuclear factor kappaB (NF-kappaB), the pivotal regulator of inflammation and the target of TNFalpha.Collectively, our findings provide the first evidence for NF-kappaB-mediated inhibition of COMT expression in the central nervous system, suggesting that COMT contributes to the pathogenesis of inflammatory pain states.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Neurosensory Disorders, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7455, USA. tchivilei@dentistry.unc.edu

ABSTRACT

Background: Catechol-O-methyltransferase (COMT), an enzyme that metabolizes catecholamines, has recently been implicated in the modulation of pain. Specifically, low COMT activity is associated with heightened pain perception and development of musculoskeletal pain in humans as well as increased experimental pain sensitivity in rodents.

Results: We report that the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) downregulates COMT mRNA and protein in astrocytes. Examination of the distal COMT promoter (P2-COMT) reveals a putative binding site for nuclear factor kappaB (NF-kappaB), the pivotal regulator of inflammation and the target of TNFalpha. Cell culture assays and functional deletion analyses of the cloned P2-COMT promoter demonstrate that TNFalpha inhibits P2-COMT activity in astrocytes by inducing NF-kappaB complex recruitment to the specific kappaB binding site.

Conclusion: Collectively, our findings provide the first evidence for NF-kappaB-mediated inhibition of COMT expression in the central nervous system, suggesting that COMT contributes to the pathogenesis of inflammatory pain states.

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TNFα-mediated repression of COMT is attenuated in H4 IκBα-SR astroglial cells. Administration of TNFα (100 ng/ml) does not reduce COMT expression in H4 IκBα-SR cells as indicated by (A) a representative Western blot, (B) quantitative analysis of Western blots from experiments performed in triplicate, and (C) quantitative real-time RT-PCR analysis of MB-COMT mRNA. P > 0.05 different from untreated control.
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Figure 3: TNFα-mediated repression of COMT is attenuated in H4 IκBα-SR astroglial cells. Administration of TNFα (100 ng/ml) does not reduce COMT expression in H4 IκBα-SR cells as indicated by (A) a representative Western blot, (B) quantitative analysis of Western blots from experiments performed in triplicate, and (C) quantitative real-time RT-PCR analysis of MB-COMT mRNA. P > 0.05 different from untreated control.

Mentions: Finally, to test effect of NF-κB pathway on endogenous COMT expression, we also treated H4 IκBα-SR cells with TNFα. Consistent with reporter assay results, TNFα was unable to significantly repress endogenous COMT protein and mRNA levels in H4 IκBα-SR cells (P > 0.05 for protein level and P > 0.05 for mRNA; Figure 3A, B, and 3C).


Characterization of NF-kB-mediated inhibition of catechol-O-methyltransferase.

Tchivileva IE, Nackley AG, Qian L, Wentworth S, Conrad M, Diatchenko LB - Mol Pain (2009)

TNFα-mediated repression of COMT is attenuated in H4 IκBα-SR astroglial cells. Administration of TNFα (100 ng/ml) does not reduce COMT expression in H4 IκBα-SR cells as indicated by (A) a representative Western blot, (B) quantitative analysis of Western blots from experiments performed in triplicate, and (C) quantitative real-time RT-PCR analysis of MB-COMT mRNA. P > 0.05 different from untreated control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662804&req=5

Figure 3: TNFα-mediated repression of COMT is attenuated in H4 IκBα-SR astroglial cells. Administration of TNFα (100 ng/ml) does not reduce COMT expression in H4 IκBα-SR cells as indicated by (A) a representative Western blot, (B) quantitative analysis of Western blots from experiments performed in triplicate, and (C) quantitative real-time RT-PCR analysis of MB-COMT mRNA. P > 0.05 different from untreated control.
Mentions: Finally, to test effect of NF-κB pathway on endogenous COMT expression, we also treated H4 IκBα-SR cells with TNFα. Consistent with reporter assay results, TNFα was unable to significantly repress endogenous COMT protein and mRNA levels in H4 IκBα-SR cells (P > 0.05 for protein level and P > 0.05 for mRNA; Figure 3A, B, and 3C).

Bottom Line: Specifically, low COMT activity is associated with heightened pain perception and development of musculoskeletal pain in humans as well as increased experimental pain sensitivity in rodents.Examination of the distal COMT promoter (P2-COMT) reveals a putative binding site for nuclear factor kappaB (NF-kappaB), the pivotal regulator of inflammation and the target of TNFalpha.Collectively, our findings provide the first evidence for NF-kappaB-mediated inhibition of COMT expression in the central nervous system, suggesting that COMT contributes to the pathogenesis of inflammatory pain states.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Neurosensory Disorders, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7455, USA. tchivilei@dentistry.unc.edu

ABSTRACT

Background: Catechol-O-methyltransferase (COMT), an enzyme that metabolizes catecholamines, has recently been implicated in the modulation of pain. Specifically, low COMT activity is associated with heightened pain perception and development of musculoskeletal pain in humans as well as increased experimental pain sensitivity in rodents.

Results: We report that the proinflammatory cytokine tumor necrosis factor alpha (TNFalpha) downregulates COMT mRNA and protein in astrocytes. Examination of the distal COMT promoter (P2-COMT) reveals a putative binding site for nuclear factor kappaB (NF-kappaB), the pivotal regulator of inflammation and the target of TNFalpha. Cell culture assays and functional deletion analyses of the cloned P2-COMT promoter demonstrate that TNFalpha inhibits P2-COMT activity in astrocytes by inducing NF-kappaB complex recruitment to the specific kappaB binding site.

Conclusion: Collectively, our findings provide the first evidence for NF-kappaB-mediated inhibition of COMT expression in the central nervous system, suggesting that COMT contributes to the pathogenesis of inflammatory pain states.

Show MeSH
Related in: MedlinePlus