Abstract

Background:

Mitochondrial function is implicated as a target of environmental toxicants and found in disease or injury models, contributing to acute and chronic inflammation. One mechanism by which mitochondrial damage can propagate inflammation is via activation of the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family, pyrin domain-containing receptor (NLRP)3 inflammasome, a protein complex that processes mature interleukin $\left(\text{IL}\right)\text{-}1\mathrm{\beta }$. $\text{IL-}1\mathrm{\beta }$ plays an important role in the innate immune response and dysregulation is associated with autoinflammatory disorders.

Objective:

The objective was to evaluate whether mitochondrial toxicants recruit inflammasome activation and $\text{IL-}1\mathrm{\beta }$ processing.

Method:

Murine macrophages (RAW 264.7) exposed to tri-organotins (triethyltin bromide (TETBr), trimethyltin hydroxide (TMTOH), triphenyltin hydroxide (TPTOH), bis(tributyltin)oxide) [Bis(TBT)Ox] were examined for pro-inflammatory cytokine induction. TMTOH and TETBr were examined in RAW 264.7 and bone marrow-derived macrophages for mitochondrial bioenergetics, reactive oxygen species (ROS) production, and inflammasome activation via visualization of aggregate formation, caspase-1 flow cytometry, $\text{IL-}1\mathrm{\beta }$ enzyme-linked immunosorbent assay and Western blots, and microRNA (miRNA) and mRNA arrays.

Results:

TETBr and TMTOH induced inflammasome aggregate formation and $\text{IL-}1\mathrm{\beta }$ release in lipopolysaccharide (LPS)-primed macrophages. Mitochondrial bioenergetics and mitochondrial ROS were suppressed. Il1a and Il1b induction with LPS or $\text{LPS}+\text{ATP}$ challenge was diminished. Differential miRNA and mRNA profiles were observed. Lower miR-151-3p targeted cyclic adenosine monophosphate (cAMP)-mediated and AMP-activated protein kinase signaling pathways; higher miR-6909-5p, miR-7044-5p, and miR-7686-5p targeted Wnt beta-catenin signaling, retinoic acid receptor activation, apoptosis, signal transducer and activator of transcription 3, IL-22, IL-12, and IL-10 signaling. Functional enrichment analysis identified apoptosis and cell survival canonical pathways.

Conclusion:

Select mitotoxic tri-organotins disrupted murine macrophage transcriptional response to LPS, yet triggered inflammasome activation. The differential response pattern suggested unique functional changes in the inflammatory response that may translate to suppressed host defense or prolong inflammation. We posit a framework to examine immune cell effects of environmental mitotoxic compounds for adverse health outcomes. https://doi.org/10.1289/EHP8314

中文翻译：

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评估线粒体功能和炎症巨噬细胞活化的小鼠巨噬细胞暴露于选择线粒体的Tri-Organotin化合物的关联。

摘要

背景：

线粒体功能被认为是环境毒物的靶标，并存在于疾病或损伤模型中，导致急性和慢性炎症。线粒体损伤可以传播炎症的一种机制是通过激活核苷酸结合寡聚化域（NOD）样受体（NLR）家族，含吡喃域的受体（NLRP）3炎性小体（一种处理成熟白介素的蛋白质复合物）来激活。$（\text{白介素}）\text{--}\mathrm{1个}\mathrm{\beta }$。 $\text{白介素}\mathrm{1个}\mathrm{\beta }$ 在先天免疫反应中起重要作用，并且调节异常与自身炎性疾病有关。

客观的：

目的是评估线粒体毒物是否招募炎症小体活化和 $\text{白介素}\mathrm{1个}\mathrm{\beta }$ 加工。

方法：

检查了暴露于三有机锡（溴化三乙基锡（TETBr），氢氧化三甲基锡（TMTOH），氢氧化三苯基锡（TPTOH），双（三丁基锡）氧化物）[Bis（TBT）Ox]的鼠巨噬细胞（RAW 264.7）的促炎性细胞因子。就职。通过观察聚集体形成，caspase-1流式细胞术，在RAW 264.7和骨髓衍生的巨噬细胞中检测了TMTOH和TETBr的线粒体生物能，活性氧（ROS）产生和炎症小体活化，$\text{白介素}\mathrm{1个}\mathrm{\beta }$ 酶联免疫吸附测定和Western印迹，以及microRNA（miRNA）和mRNA阵列。

结果：

TETBr和TMTOH诱导炎性体聚集物形成和 $\text{白介素}\mathrm{1个}\mathrm{\beta }$在脂多糖（LPS）启动的巨噬细胞中释放。线粒体生物能学和线粒体ROS被抑制。用LPS诱导Il1a和Il1b或$\text{脂多糖}+\text{三磷酸腺苷}$挑战减少了。观察到不同的miRNA和mRNA谱。较低的miR-151-3p靶向环磷酸腺苷（cAMP）介导和AMP激活的蛋白激酶信号传导途径；更高的miR-6909-5p，miR-7044-5p和miR-7686-5p靶向Wntβ -catenin信号传导，视黄酸受体激活，细胞凋亡，信号转导和转录激活因子3，IL-22，IL-12和IL-10信号传导。功能富集分析确定了凋亡和细胞存活的经典途径。

结论：

选择具有线粒体毒性的三有机锡可破坏鼠巨噬细胞对LPS的转录反应，但会触发炎症小体活化。差异反应模式提示炎症反应中独特的功能变化，可能转变为抑制宿主防御或延长炎症。我们提出了一个框架，以检查环境化学毒性化合物对健康不利影响的免疫细胞作用。https://doi.org/10.1289/EHP8314