背景:我们以前的研究证明了痤疮酸杆菌之间的密切关系(C.痤疮),氧化应激,和痤疮炎症。丁香酸(SA)是一种广泛用于抗菌的植物,抗炎,和抗氧化活性,但缺乏痤疮的数据。本研究旨在探讨SA对痤疮C.acnes诱导的痤疮炎症的作用及机制。
方法:使用SA暴露HaCaT角质形成细胞后,我们重新评估了SA对细胞活力的影响,细胞凋亡,ROS,CAT,SOD,以及热灭活的痤疮梭菌处理的HaCaT细胞中的其他炎性变量。接下来,诱导小鼠痤疮炎症,向ICR小鼠的右耳皮内注射活痤疮梭菌。然后检查SA对该炎症的作用。此外,我们通过ELISA法探讨了SA对PPARγ/Nrf2和NLRP3/caspase-1/IL-1β通路的作用机制,免疫荧光显微镜,和蛋白质印迹分析。
结果:热杀伤痤疮丙酸杆菌引发显著的细胞凋亡,ROS生产,白细胞介素(IL)-1β,IL-18、IL-6和TNF-α释放,降低SOD和CAT活性,并上调HaCaT细胞中蛋白质的表达,包括上调IL-1β,PPARγ,Nrf2,HO-1,NQO1,NLRP3和caspase-1,而SA通过部分削弱PPARγ激活来抑制这些作用。此外,PPARγ沉默减少痤疮杆菌诱导的IL-1β分泌和细胞内ROS的产生,下调Nrf2的表达。Nrf2激活剂(SFN)通过抗氧化机制增强抗炎活性,促进细胞内ROS的产生,降低SOD和CAT活性,促进ROS的增加,HO-1、NQO1和IL-1β水平,而PPARγ抑制剂(GW662)在热杀死的痤疮梭菌处理的细胞中有效地抑制这种作用。最后,SA还表现出耳朵发红的显着改善,肿胀,和PPARγ的表达,体内NLRP3和IL-1β。
结论:SA通过激活PPARγ/Nrf2-抗氧化途径调节NLRP3/caspase-1/IL-1β信号轴,从而抑制痤疮梭菌诱导的炎症,提出了一种新的治疗寻常痤疮的可能性。
BACKGROUND: Our previous studies have demonstrated a strong relationship betweenCutibacterium acnes(C. acnes), oxidative stress, and acne inflammation. Syringic acid (SA) is a plant widely used for its antimicrobial, anti-inflammatory, and antioxidant activities, but lacking data on acne. This study aims to investigate the effect and mechanism of SA on acne inflammation induced by C. acnes in vitro and in vivo.
METHODS: After using the SA to expose HaCaT keratinocytes, we reevaluated the effect of the SA on cell viability, cell apoptosis, ROS, CAT, SOD, and other inflammatory variables in the heat-killed C. acnes-treated HaCaT cells. Next, to induce mice with acne inflammation, ICR mice were given an intradermal injection of live C. acnes into their right ears. The effect of SA on this inflammation was then examined. Moreover, we explored the mechanism of SA on PPARγ/Nrf2 and NLRP3/caspase-1/IL-1β pathways by ELISA, immunofluorescence microscopy, and western blot assay.
RESULTS: Heat-killed C. acnes triggered remarkable cell apoptosis, ROS production, interleukin (IL)-1β, IL-18, IL-6, and TNF-α release, reduced SOD and CAT activity, and upregulated the expression of proteins in HaCaT cells, including up-regulating IL-1β, PPARγ, Nrf2, HO-1, NQO1, NLRP3, and caspase-1, whereas SA inhibited these effects by partially impairing PPARγ activation. In addition, PPARγ silencing decreased C. acnes-induced IL-1β secretion and the production of intracellular ROS, down-regulating the expression of Nrf2. Nrf2 activator (SFN) enhanced anti-inflammatory activity through antioxidant mechanisms, boosting intracellular ROS production, reducing SOD and CAT activity, and promoting the increase in ROS, HO-1, NQO1, and IL-1β levels, while PPARγ inhibitor (GW662) effectively inhibited this effect in heat-killed C. acnes-treated cells. Finally, SA also exhibited notable improvements in ear redness, swelling, and the expression of PPARγ, NLRP3, and IL-1β in vivo.
CONCLUSIONS: SA inhibited C. acnes-induced inflammation via regulating the NLRP3/caspase-1/IL-1β signaling axis by activating the PPARγ/Nrf2-antioxidant pathway, suggesting a new treatment possibility for acne vulgaris.