A MzS 2024 PAR2 ko AngII Raw data.xlsx

<b>Aims:</b> Activation of Protease Activated Receptor 2 (PAR2) has been shown to be involved in regulation of injury-related processes including inflammation, fibrosis and hypertrophy. <b>Methods:</b> Hypertension was induced in 12 weeks old wildtype (wt, n=8) and PAR2 deficient mice (n=9) by continuous infusion with angiotensin II for 4 weeks using osmotic minipumps. At the end, hearts were collected for analysis of left ventricular hypertrophy (LVH), myocardial capillary supply, fibrosis and localization of PAR2 expression using histological, immunohistological and mRNA expression analysis techniques. In addition, rat cardiac fibroblasts were treated with angiotensin II and PAR2 was inhibited by a blocking antibody and AZ3451.<b>Results:</b> Cardiac PAR2 mRNA expression was downregulated by 40±20% in wt mice treated with AngII compared to untreated controls. Four weeks after AngII treatment, LVH was significantly increased in AngII-treated wt mice compared to similarly treated PAR2-deficient animals as determined by relative heart weight, left ventricular cross-sectional area, and analysis of ventricular lumen area determined on sections. Treatment of wt mice resulted in an approximately 3-fold increase in cardiac expression of FGF23, which was 50% lower in PAR2-deficient animals compared to wt animals and therefore no longer significantly different from expression levels in untreated control mice. In contrast, cardiac interstitial fibrosis was significantly higher in PAR2-deficient mice compared to similar treated wt controls, as assessed by sirius red staining (&gt;3-fold) and collagen IV staining (&gt;2-fold). Additional experiments with isolated cardiac fibroblasts showed induction of pro-fibrotic genes when treated with PAR2 inhibitors. <b>Conclusion:</b> In angiotensin II-induced cardiac injury, PAR2 deficiency has an ambivalent effect, enhancing fibrosis on the one hand, but reducing LVH on the other.

**研究目的**：已有研究证实，蛋白酶激活受体2（Protease Activated Receptor 2, PAR2）参与调控炎症、纤维化与心肌肥厚等损伤相关病理过程。
**研究方法**：本研究采用渗透微型泵持续灌注血管紧张素II，对12周龄野生型（wildtype, wt，n=8）及PAR2基因敲除小鼠（n=9）构建高血压模型，造模时长为4周。造模结束后，收集心脏样本，通过组织学、免疫组织化学及mRNA表达分析技术，检测左心室肥厚（left ventricular hypertrophy, LVH）、心肌毛细血管分布、纤维化程度及PAR2的表达定位。此外，本研究以血管紧张素II处理大鼠心脏成纤维细胞，并通过封闭抗体与AZ3451抑制PAR2活性。
**研究结果**：经血管紧张素II处理的野生型小鼠心脏中，PAR2的mRNA表达水平较未处理对照组下调40%±20%。血管紧张素II处理4周后，通过相对心脏重量、左心室横截面积及切片心室腔面积分析结果显示，野生型小鼠的左心室肥厚程度显著高于同处理的PAR2基因敲除小鼠。野生型小鼠经血管紧张素II处理后，心脏中成纤维细胞生长因子23（FGF23）的表达量约升高3倍，而PAR2基因敲除小鼠的FGF23表达量较野生型小鼠低50%，其表达水平与未处理对照组无显著差异。与之相反，通过天狼星红染色（升高＞3倍）与IV型胶原染色（升高＞2倍）评估发现，PAR2基因敲除小鼠的心脏间质纤维化程度显著高于同处理的野生型对照组。体外分离实验进一步证实，单独使用PAR2抑制剂处理心脏成纤维细胞，可诱导促纤维化基因的表达。
**研究结论**：在血管紧张素II诱导的心脏损伤模型中，PAR2基因缺失表现出双向调控效应：一方面加重心脏间质纤维化，另一方面则减轻左心室肥厚。