- 學位論文
自由基在痤瘡桿菌誘導巨噬細胞一氧化氮合成酶和環氧化酵素活化之角色
The role of ROS in Propionibacterium acnes-induced iNOS and COX-2 expressions in macrophage
摘要
痤瘡桿菌 (Propionibacterium acnes, P. acnes) 是一種革蘭氏陽性的細菌，會在溫暖厭氧的環境下生長，主要存在於一般人的皮膚當中，目前已知是引起皮膚發炎的主要病原菌。在青春痘的形成過程中，痤瘡桿菌的大量繁殖會引起發炎物質及自由基 (reactive oxygen species, ROS) 的釋放，而先前的文獻中指出，痤瘡桿菌會藉由mitogen-activated protein kinase (MAPK) 和nuclear factor kappa B (NF-κB) 途徑造成角質細胞的發炎，但是痤瘡桿菌在巨噬細胞中造成的發炎反應機制尚未明確。因此，本篇論文主要目的為針對巨噬細胞研究痤瘡桿菌引起的發炎反應之分子機制。目前的結果顯示，痤瘡桿菌在巨噬細胞中具有誘導nitric oxide (NO) , prostaglandin E2 (PGE2) 和自由基的產生，並且造成細胞的生長受到抑制，以及在蛋白質inducible-NOS (iNOS) 和 cyclooxygenase-2 (COX-2) 的大量表現。在巨噬細胞受到痤瘡桿菌的刺激之下加入抗氧化劑NAC和Vitamin C，則發現自由基在此發炎反應中扮演重要的角色。此外，結果中也發現巨噬細胞在受到痤瘡桿菌刺激後引起MAPK的活化，以及iNOS和COX-2的上游，轉錄因子AP-1和NF-κB的活化，同時，加入JNK和ERK抑制劑可以保護巨噬細胞免於死亡，另外，在實驗中也發現天然物Hispolon及其結構類似合成物也會造成此保護的現象。
並列摘要
Propionibacterium acnes (P. acnes), a gram positive bacteria, has been implicated in the skin inflammation. In acne vulgaris, P. acnes develop the primarily response which induced production of cytokines, chemokines and reactive oxygen species (ROS). The inflammatory mechanisms of P. acnes in keratinocytes have been indicated via mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathway. However, the mechanisms of P. acnes –induced inflammation in macrophages is still unclear. Thus, to investigate the molecular mechanisms of P. acnes-induced inflammatory responses in macrophages is the objective of the present study. Data of the present study show that P. acnes possess ability to induce the production of nitric oxide (NO), prostaglandin E2 (PGE2), and ROS in macrophages with decreases in cell viability and increases in expression of inducible-NOS (iNOS) and cyclooxygenase-2 (COX-2) in both protein and mRNA levels. Macrophages were stimulated by P. acnes with antioxidants (NAC, Vitamin C and DPI) showing ROS played a critical initial role in P. acnes-induced inflammatory responses. Furthermore, alternative activations of MAPKs by P. acnes were investigated, and that was located at the upstream of iNOS and COX-2 activation in macrophages via AP-1/NF-κB transcriptional activation. Cell death elicited by P. acnes was significantly prevented by addition ERK and JNK inhibitor. The preventive effect of natural products Hispolon and its analogs on P. acnes-simulated inflammatory events in macrophages was also investigated. The inflammatory mechanism of P. acnes according with developing the effective natural compounds Hispolon for further application was first elucidated. In conclusion, ROS-dependent induction of iNOS/NO and COX-2/PGE2 by Propionibacterium acnes though ERK/JNK pathway via activation of NF-κB and AP-1 in macrophages. Hispolon possess potent anti-inflammatory effect on P. acnes-induced inflammation.