Protein kinase A enhances lipopolysaccharide-induced IL-6, IL-8, and PGE2production by human gingival fibroblasts

Ara Toshiaki, Fujinami Yoshiaki, Urano Hiroko, Hirai Kaname, Hatori Toshimi, Miyazawa, Miyazawa Hiroo

Description

Objective Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontal tissues, leading to alveolar bone loss in severe clinical cases. Interleukin (IL)-6, IL-8, and the chemical mediator prostaglandin E 2 (PGE 2 ) are known to play important roles in inflammatory responses and tissue degradation. Recently, we reported that the protein kinase A (PKA) inhibitor H-89 suppresses lipopolysaccharide (LPS)-induced IL-8 production by human gingival fibroblasts (HGFs). In the present study, the relevance of the PKA activity and two PKA-activating drugs, aminophylline and adrenaline, to LPS-induced inflammatory cytokines (IL-6 and IL-8) and PGE 2 by HGFs were examined. Methods HGFs were treated with LPS from Porphyromonas gingivalis and H-89, the cAMP analog dibutyryl cyclic AMP (dbcAMP), aminophylline, or adrenaline. After 24 h, IL-6, IL-8, and PGE 2 levels were evaluated by ELISA. Results H-89 did not affect LPS-induced IL-6 production, but suppressed IL-8 and PGE 2 production. In contrast, dbcAMP significantly increased LPS-induced IL-6, IL-8, and PGE 2 production. Up to 10 μg/ml of aminophylline did not affect LPS-induced IL-6, IL-8, or PGE 2 production, but they were significantly increased at 100 μg/ml. Similarly, 0.01 μg/ml of adrenaline did not affect LPS-induced IL-6, IL-8, or PGE 2 production, but they were significantly increased at concentrations of 0.1 and 1 μg/ml. In the absence of LPS, H-89, dbcAMP, aminophylline, and adrenaline had no relevance to IL-6, IL-8, or PGE 2 production. Conclusion These results suggest that the PKA pathway, and also PKA-activating drugs, enhance LPS-induced IL-6, IL-8, and PGE 2 production by HGFs. However, aminophylline may not have an effect on the production of these molecules at concentrations used in clinical settings (8 to 20 μg/ml in serum). These results suggest that aminophylline does not affect inflammatory responses in periodontal disease.

Sujets

• Protein kinase A
• Interleukin
• Prostaglandin E2

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 4
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Araet al.Journal of Negative Results in BioMedicine2012,11:10 http://www.jnrbm.com/content/11/1/10

R E S E A R C HOpen Access Protein kinase A enhances lipopolysaccharide induced IL6, IL8, and PGE 2 production by human gingival fibroblasts 1* 12 31 4 Toshiaki Ara, Yoshiaki Fujinami , Hiroko Urano , Kaname Hirai , Toshimi Hatoriand Hiroo Miyazawa

Abstract Objective:Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontal tissues, leading to alveolar bone loss in severe clinical cases. Interleukin (IL)6, IL8, and the chemical mediator prostaglandin E 2 (PGE 2 ) are known to play important roles in inflammatory responses and tissue degradation. Recently, we reported that the protein kinase A (PKA) inhibitor H89 suppresses lipopolysaccharide (LPS)induced IL8 production by human gingival fibroblasts (HGFs). In the present study, the relevance of the PKA activity and two PKAactivating drugs, aminophylline and adrenaline, to LPSinduced inflammatory cytokines (IL6 and IL8) and PGE 2 by HGFs were examined. Methods:HGFs were treated with LPS fromPorphyromonas gingivalisand H89, the cAMP analog dibutyryl cyclic AMP (dbcAMP), aminophylline, or adrenaline. After 24 h, IL6, IL8, and PGE 2 levels were evaluated by ELISA. Results:H89 did not affect LPSinduced IL6 production, but suppressed IL8 and PGE 2 production. In contrast, dbcAMP significantly increased LPSinduced IL6, IL8, and PGE 2 production. Up to 10μg/ml of aminophylline did not affect LPSinduced IL6, IL8, or PGE 2 production, but they were significantly increased at 100μg/ml. Similarly, 0.01μg/ml of adrenaline did not affect LPSinduced IL6, IL8, or PGE 2 production, but they were significantly increased at concentrations of 0.1 and 1μg/ml. In the absence of LPS, H89, dbcAMP, aminophylline, and adrenaline had no relevance to IL6, IL8, or PGE 2 production. Conclusion:These results suggest that the PKA pathway, and also PKAactivating drugs, enhance LPSinduced IL6, IL8, and PGE 2 production by HGFs. However, aminophylline may not have an effect on the production of these molecules at concentrations used in clinical settings (8 to 20μg/ml in serum). These results suggest that aminophylline does not affect inflammatory responses in periodontal disease. Keywords:Protein kinase A, interleukin, prostaglandin E 2 , human gingival fibroblast

Background Periodontal disease is accompanied by inflammation of the gingiva and destruction of periodontal tissues, lead ing to alveolar bone loss in severe clinical cases. Inter leukin (IL)6, IL8, and prostaglandin E 2 (PGE 2 ) are known to play important roles in inflammatory responses and tissue degradation. IL6 has the ability to induce osteoclastogenesis [1,2]. IL8 acts as a chemoat tractant for neutrophils [3] that produce proteases such

* Correspondence: [e-mail] 1 Department of Pharmacology, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 3990781, Japan Full list of author information is available at the end of the article

as cathepsin, elastase, or matrix metalloproteinase (MMP)8, leading to tissue degradation. PGE 2 has sev eral functions in vasodilation, the enhancement of vas cular permeability and pain, and the induction of osteoclastogenesis, and is believed to play important roles in inflammatory responses and alveolar bone resorption in periodontal disease [4]. Recently, we reported that the protein kinase A (PKA) inhibitor H89 suppresses LPSinduced IL8 production by human gingival fibroblasts (HGFs) [5]. This finding suggests that the PKA pathway enhances LPSinduced IL8 production, and that taking PKAactivating drugs results in an increase of inflammatory cytokines

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