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. 2010 Aug;120(8):2910-9.
doi: 10.1172/JCI42273. Epub 2010 Jul 26.

Nicotinic acid- and monomethyl fumarate-induced flushing involves GPR109A expressed by keratinocytes and COX-2-dependent prostanoid formation in mice

Julien Hanson  1 , Andreas Gille, Sabrina Zwykiel, Martina Lukasova, Björn E Clausen, Kashan Ahmed, Sorin Tunaru, Angela Wirth, Stefan Offermanns
Affiliations

Nicotinic acid- and monomethyl fumarate-induced flushing involves GPR109A expressed by keratinocytes and COX-2-dependent prostanoid formation in mice

Julien Hanson et al. J Clin Invest. 2010 Aug.

Abstract

The antidyslipidemic drug nicotinic acid and the antipsoriatic drug monomethyl fumarate induce cutaneous flushing through activation of G protein-coupled receptor 109A (GPR109A). Flushing is a troublesome side effect of nicotinic acid, but may be a direct reflection of the wanted effects of monomethyl fumarate. Here we analyzed the mechanisms underlying GPR109A-mediated flushing and show that both Langerhans cells and keratinocytes express GPR109A in mice. Using cell ablation approaches and transgenic cell type-specific GPR109A expression in Gpr109a-/- mice, we have provided evidence that the early phase of flushing depends on GPR109A expressed on Langerhans cells, whereas the late phase is mediated by GPR109A expressed on keratinocytes. Interestingly, the first phase of flushing was blocked by a selective cyclooxygenase-1 (COX-1) inhibitor, and the late phase was sensitive to a selective COX-2 inhibitor. Both monomethyl fumarate and nicotinic acid induced PGE2 formation in isolated keratinocytes through activation of GPR109A and COX-2. Thus, the early and late phases of the GPR109A-mediated cutaneous flushing reaction involve different epidermal cell types and prostanoid-forming enzymes. These data will help to guide new efficient approaches to mitigate nicotinic acid-induced flushing and may help to exploit the potential antipsoriatic effects of GPR109A agonists in the skin.

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Figures

Figure 1
Figure 1. Keratinocytes express GPR109A.
(A) Scheme of the Gpr109a reporter BAC transgene. (B and C) Gpr109a expression in the epidermis. Shown are sections through the epidermis (B) and en face views of the epidermis (C) from WT and Gpr109amRFP mice. Cell nuclei were stained with DAPI, and keratinocytes and Langerhans cells were visualized by immunofluorescence labeling with antibodies directed against MHC-II (B) and cytokeratin (C). mRFP fluorescence was detected in parallel to visualize GPR109A expression. Dotted line denotes the basal membrane. Sb, stratum basale; Sg, stratum granulosum; Ss, stratum spinosum. Scale bars: 10 μm (B); 20 μm (C). (D) RT-PCR to analyze Gpr109a expression in human and mouse keratinocytes. The cDNA synthesis reaction was performed in the absence or presence of RT. (E) Effects of 100 μM nicotinic acid (NA) and 10% FBS on ERK1/2 phosphorylation in keratinocytes prepared from WT or Gpr109a–/– mice, analyzed with an antibody recognizing phosphorylated ERK1/2. In parallel, the total amount of ERK1/2 was determined. (F and G) Effect of 100 μM NA on free [Ca2+]i in Fura-2–loaded keratinocytes from WT (F) and Gpr109a–/– (G) mice. ATP (100 μM) was applied as a positive control.
Figure 2
Figure 2. GPR109A expressed by Langerhans cells mediates only the early phase of nicotinic acid–induced flushing.
(A) Experimental scheme. At 1 day after irradiation, Langerin-DTR mice were transplanted with BM from WT or Gpr109a–/– mice carrying in both cases Gpr109amRFP (reporter). At 3 months after transplantation, both groups were treated with DT, and 3 months later, nicotinic acid–induced flushing was evaluated. LC, Langerhans cells; kerat, keratinocytes. (B) Fluorescence image of epidermal sheet from transplanted animals before DT treatment stained with an anti–MHC-II antibody and analyzed for mRFP expression. (C and D) Nicotinic acid (250 μg/g) induced flushing in both experimental groups before DT treatment. (E) Fluorescent images of epidermal sheets of transplanted animals stained with anti–MHC-II antibodies and analyzed for mRFP expression 3 months after DT treatment. (F and G) Effect of nicotinic acid on flushing in mice transplanted with WT and Gpr109a–/– BM 3 months after DT treatment. Scale bars: 20 μm. Data are representative of at least 3 independent experiments. Results in D and G are mean ± SEM (n ≥ 6). **P ≤ 0.01.
Figure 3
Figure 3. Expression of GPR109A in keratinocytes is sufficient to mediate the late phase of nicotinic acid–induced flushing.
(A) Scheme of the Krt5Gpr109a-mRFP BAC transgene. (B) Fluorescence image of epidermal sheets prepared from WT and Krt5Gpr109a-mRFP mice. Shown are en face views of epidermal sheets stained with anti–MHC-II anti­bodies and analyzed for expression of mRFP. Scale bars: 25 μm. (C and D) Effect of 250 μg/g nicotinic acid and 10 μg/g monomethyl fumarate (MF) on flushing in WT, Gpr109a–/–, and Gpr109a–/–Krt5Gpr109a-mRFP mice. The experiments shown are representative of at least 9 experiments. Data in D show the evaluation of the late phase of flushing (second peak) and are presented as mean ± SEM (n > 9). **P ≤ 0.01, ***P ≤ 0.001 versus Gpr109a–/–.
Figure 4
Figure 4. Roles of COX-1 and COX-2 in GPR109A-mediated flushing.
(A) RT-PCR to determine COX-1 and COX-2 expression in human and mouse keratinocytes, and analysis of COX-2 expression in the epidermis. The cDNA synthesis reaction was performed in the absence or presence of RT. Shown are transversal sections of tail epidermis stained with DAPI and with antibodies specific to COX-2 and MHC-II. Dotted line denotes the basal membrane. Scale bars: 10 μm; 2 μm (insets). (B–F) Flushing responses induced by 250 μg/g nicotinic acid and 10 μg/g monomethyl fumarate in WT mice pretreated 45 minutes prior to the injection of nicotinic acid or monomethyl fumarate in the absence (B) or presence of 5 μg/g FR122047 (FR; C), 10 μg/g NS398 (NS; D), or pretreated with both inhibitors (E), or in GPR109A–/–Krt5Gpr109a-mRFP mice pretreated with the same doses of FR122047 or NS398 (F). Shown are representative traces as well as quantification of at least 4 experiments. Data are mean ± SEM (n ≥ 4). *P ≤ 0.05; **P ≤ 0.01.
Figure 5
Figure 5. GPR109A-mediated stimulation of prostanoid release from keratinocytes.
(A) RT-PCR to determine the expression of PGE2 and PGD2 synthases as well as GAPDH in human and mouse keratinocytes. The cDNA synthesis reaction was performed in the absence or presence of RT. (B) Effect of nicotinic acid on the release of PGE2 from mouse keratinocytes, shown for increasing time periods. (C and D) Effect of nicotinic acid and monomethyl fumarate on the release of PGE2 from mouse (C) and human keratinocytes (D). Mouse keratinocytes were prepared from WT or Gpr109a–/– mice. Keratinocytes were left untreated or were pretreated with NS398 (10 μM) or FR122047 (1 μM). Nicotinic acid and monomethyl fumarate were applied at a concentration of 500 μM. Data shown are mean ± SEM (n ≥ 4). *P ≤ 0.05, **P ≤ 0.01 versus samples without agonist. (E) Proposed model for the local mechanisms underlying GPR109A-mediated flushing. Application of GPR109A agonists induces a biphasic increase in dermal blood flow, which results from activation of GPR109A on Langerhans cells and keratinocytes. The first phase is induced via activation of GPR109A on Langerhans cells, and GPR109A on keratinocytes is responsible for the late phase of the response. Whereas Langerhans cell–mediated flushing involves COX-1, PGD2, and PGE2, keratinocyte-mediated late-phase flushing involves COX-2 and PGE2.
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References

    1. Canner PL, et al. Fifteen year mortality in Coronary Drug Project patients: long-term benefit with niacin. J Am Coll Cardiol. 1986;8(6):1245–1255. doi: 10.1016/S0735-1097(86)80293-5. - DOI - PubMed
    1. Carlson LA. Nicotinic acid: the broad-spectrum lipid drug. A 50th anniversary review. J Intern Med. 2005;258(2):94–114. doi: 10.1111/j.1365-2796.2005.01528.x. - DOI - PubMed
    1. Meyers CD, Kamanna VS, Kashyap ML. Niacin therapy in atherosclerosis. Curr Opin Lipidol. 2004;15(6):659–665. doi: 10.1097/00041433-200412000-00006. - DOI - PubMed
    1. Gille A, Bodor ET, Ahmed K, Offermanns S. Nicotinic acid: pharmacological effects and mechanisms of action. Annu Rev Pharmacol Toxicol. 2008;48:79–106. doi: 10.1146/annurev.pharmtox.48.113006.094746. - DOI - PubMed
    1. Digby JE, Lee JM, Choudhury RP. Nicotinic acid and the prevention of coronary artery disease. Curr Opin Lipidol. 2009;20(4):321–326. doi: 10.1097/MOL.0b013e32832d3b9d. - DOI - PubMed

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