P Luckprom

Srinakharinwirot University, Krung Thep, Bangkok, Thailand

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Publications (7)10.5 Total impact

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    ABSTRACT: Pannexin 1 (Panx1) has been found to form nonjunctional hemichannels. It is also proposed to combine with the P2X7 receptor, forming a complex involved in adenosine triphosphate (ATP)-induced interleukin-1beta (IL-1β) release in macrophages. Previously, we reported that mechanical stress induced IL-1β expression via the ATP/P2X7 receptor-dependent pathway in human periodontal ligament (HPDL) cells and that ATP was released through the connexin 43 (Cx43) hemichannel. In the present work, we examined the role of Panx1 in stress-induced IL-1β induction in HPDL cells. Cultured HPDL cells were treated with compressive loading or ATP to stimulate IL-1β expression. Inhibitors, antagonists and the small interfering RNA technique were used to investigate the involvement of Panx1 in IL-1β induction. Co-immunoprecipitation (Co-IP) and immunostaining were used to determine the association of Panx1 with the P2X7 receptor. The IL-1β release mechanism was analyzed using inhibitors. Blocking Panx1 significantly decreased ATP release, as well as IL-1β up-regulation, upon stimulation with stress or ATP. Co-IP revealed the association of Panx1 and the P2X7 receptor in HPDL cells, which was increased in response to mechanical loading. Pretreatment with vesicular trafficking inhibitors significantly reduced the amount of IL-1β released from stimulated cells, suggesting that IL-1β might be released through vesicles. We clearly illustrated the contribution of Panx1 in ATP release, as well as in IL-1β induction in HPDL cells. The association of Panx1 and the P2X7 receptor might be required for IL-1β induction, and their possible novel role in IL-1β vesicular release was indicated.
    Journal of Periodontal Research 11/2013; · 1.99 Impact Factor
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    ABSTRACT: BACKGROUND AND OBJECTIVE: Mechanical stress is an important factor in maintaining homeostasis of the periodontium. Interleukin-1beta (IL-1β) and adenosine triphosphate (ATP) are considered potent inflammatory mediators. In macrophages, ATP-activated P2X7 receptor is involved in IL-1β processing and release. Our previous works demonstrated mechanical stress-induced expression of osteopontin and RANKL through the ATP/P2Y1 receptor in human periodontal ligament (HPDL) cells. This study was designed to examine the effect of mechanical stress on IL-1β expression in HPDL cells, as well as the mechanism and involvement of ATP and the P2 purinergic receptor. MATERIAL AND METHODS: Cultured HPDL cells were treated with continuous compressive loading. IL-1β expression was analyzed at both mRNA and protein levels, using RT-PCR and ELISA, respectively. Cell viability was examined using the MTT assay. ATP was also used to stimulate HPDL cells. Inhibitors, antagonists and the small interfering RNA (siRNA) technique were used to investigate the role of ATP and the specific P2 subtypes responsible for IL-1β induction along with the intracellular mechanism. RESULTS: Mechanical stress could up-regulate IL-1β expression through the release of ATP in HPDL cells. ATP alone was also capable of increasing IL-1β expression. The induction of IL-1β was markedly inhibited by inhibitors and by siRNA targeting the P2X7 receptor. ATP-stimulated IL-1β expression was also diminished by intracellular calcium inhibitors. CONCLUSION: Our work clearly indicates the capability of HPDL cells to respond directly to mechanical stimulation. The results signified the important roles of ATP/P2 purinergic receptors, as well as intracellular calcium signaling, in mechanical stress-induced inflammation via up-regulation of the proinflammatory cytokine, IL-1β, in HPDL cells.
    Journal of Periodontal Research 08/2012; · 1.99 Impact Factor
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    ABSTRACT: Our previous studies showed that mechanical stress could induce ATP release in human periodontal ligament (HPDL) cells. By signaling through P2 purinergic receptors, ATP increased the expression and the synthesis of osteopontin and RANKL. In this study, the mechanism of stress-induced ATP release was investigated. Continuous compressive forces were applied on cultured HPDL cells. The ATP released was measured using luciferin-luciferase bioluminescence. The expression of gap-junction proteins was examined using RT-PCR and western blot analysis. The opening of hemichannels was demonstrated by cellular uptake of a fluorescent dye, 5(6)-carboxyfluorescein, which is known to penetrate hemichannels. Intracellular signal transduction was investigated using inhibitors and antagonists. Mechanical stress induced the release of ATP into the culture medium, which was attenuated by carbenoxolone, a nonspecific gap-junction inhibitor. Addition of meclofenamic acid sodium salt, a connexin43 inhibitor, inhibited ATP release by mechanical stress. Knockdown of connexin43 expression by small interfering RNA reduced the amount of ATP released by mechanical stress, suggesting the role of connexin43 hemichannels. In addition, intracellular Ca(2+) blockers could also inhibit mechanical stress-induced ATP release and the opening of the gap junction. Our study demonstrated the involvement of gap-junction hemichannels, especially connexin43, in the stress-induced ATP-release mechanism. Furthermore, this mechanism may be regulated by the intracellular Ca(2+) signaling pathway. These results suggest an important role of gap-junction hemichannels in the function and behavior of HPDL cells.
    Journal of Periodontal Research 05/2011; 46(5):607-15. · 1.99 Impact Factor
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    ABSTRACT: Our previous study showed that human periodontal ligament cells responded to mechanical stress by increasing adenosine triphosphate (ATP) release, accompanied by the increased expression of RANKL and osteopontin. We found that the signaling pathway of mechanical stress-induced osteopontin was mediated through ATP/P2Y(1) receptor and Rho kinase activation but that of mechanical stress-induced RANKL was different. In this study, we further investigated the effect of extracellular ATP on the expression of RANKL and the mechanism involved. Human periodontal ligament cells were treated with ATP (10-40 microm). The expressions of RANKL and cyclo-oxygenase 2 (COX-2) were examined by RT-PCR and western blot analysis. The level of prostaglandin E(2) was determined using ELISA. Signaling pathways were investigated by using inhibitors and antagonist. Adenosine triphosphate induced the expression of RANKL. Indomethacin, an inhibitor of COX, could abolish the induction of RANKL expression, suggesting a COX-dependent mechanism. A cAMP-dependent protein kinase inhibitor, H89, and a nuclear factor kappaB (NF kappaB) inhibitor, pyrrolidine dithiocarbamate, inhibited RANKL expression, prostaglandin E(2) production and NF kappaB translocation. In addition, a specific P2Y(1) receptor antagonist, MRS2179, and P2Y(1) small interfering RNA diminished the effect of ATP. Extracellular ATP stimulates RANKL expression in human periodontal ligament cells through a pathway dependent on the P2Y(1) receptor, cAMP-dependent protein kinase, NF kappaB and COX. Our results suggest that, among the molecules responsible for the effect of mechanical stress, ATP participates in bone resorption or bone homeostasis by mediating its signal through the P2Y(1) receptor and the NF kappaB-COX-RANKL axis in periodontal tissue.
    Journal of Periodontal Research 03/2010; 45(3):404-11. · 1.99 Impact Factor
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    ABSTRACT: Oral lichen planus (OLP) is a common chronic inflammatory mucosal disease in which T-cell-mediated immune responses are implicated in the pathogenesis. The purpose of this study was to investigate the effect of 0.1% fluocinolone acetonide in orabase (FAO) on the in situ expression of IFN-gamma in patients with OLP. Twenty OLP patients were enrolled in this study. Biopsy specimens and serum samples were obtained before and 1-month after the treatment with 0.1% FAO. In situ expression and serum levels of IFN-gamma were determined using immunohistochemistry and ELISA, respectively. The number of IFN-gamma-positive mononuclear cells in OLP lesions before the treatment was significantly higher as compared with that after the treatment. Similarly, the mean number of total mononuclear cells was clearly decreased after the treatment. However, the serum levels of IFN-gamma were not detectable. Our results suggest that IFN-gamma expression in OLP tissue may involve in the immunopathogenesis and the treatment with 0.1% FAO had an immunomodulating effect on the decrease of IFN-gamma.
    Journal of Oral Pathology and Medicine 08/2009; 38(9):689-94. · 2.06 Impact Factor
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    ABSTRACT: Oral lichen planus (OLP) is a common oral mucosal disease that affects middle age patients. However, there are few reports about the incidence of OLP in different ethnic groups. The purpose of this study was to compare the characteristics of OLP in Thai and Croatian patients. Retrospective data were taken from medical records of 175 patients referred to the Oral Medicine Department of Chulalongkorn University and 175 patients referred to the School of Dental Medicine, University of Zagreb during the 1997-2007 period. In all patients the diagnosis of OLP was clinically and histopathologically confirmed. In Thai and Croatian OLP patients, females were predominant (the female to male ratio was 3.5:1). Croatian OLP patients were older with a significant age difference between female Thai and Croatian OLP patients (p<0.05). Atrophic-erosive type of OLP was common in Thai patients, whereas reticular OLP was predominant in Croatians (p<0.001). Burning sensation was the most common chief complaint in both ethnic groups. Significant differences between the two ethnic groups were found in the sites of OLP lesions as well as in the occurrence of pain, roughness and white patches, systemic diseases and use of medication (p<0.05). Croatian patients had more systemic diseases and took more medications than Thai. Three cases showed dysplasia in either group, whereas only one Thai patient developed squamous cell carcinoma. Although Thai and Croatian patients differed significantly according to the clinical type of OLP, the rate of malignant transformation was very low.
    Acta dermatovenerologica Croatica: ADC / Hrvatsko dermatolosko drustvo 05/2009; 17(1):2-8. · 0.48 Impact Factor
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Publication Stats

25 Citations
10.50 Total Impact Points


  • 2013
    • Srinakharinwirot University
      • Faculty of Dentistry
      Krung Thep, Bangkok, Thailand
  • 2010–2013
    • Chulalongkorn University
      • • Faculty of Dentistry
      • • Department of Anatomy (Dentistry)
      Krung Thep, Bangkok, Thailand