Meyer Zu Schwabedissen Albrecht, Vergarajauregui Silvia, Bertog Marko, Amann Kerstin, Engel Felix B, Daniel Christoph
Department of Nephropathology, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.
Department of Nephropathology, Institute of Pathology and Department of Cardiology, Experimental Renal and Cardiovascular Research, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
PLoS One. 2024 Dec 5;19(12):e0310095. doi: 10.1371/journal.pone.0310095. eCollection 2024.
Activation of Protease Activated Receptor 2 (PAR2) has been shown to be involved in regulation of injury-related processes including inflammation, fibrosis and hypertrophy. In this study we will investigate the role of PAR2 in cardiac injury in a mouse model of hypertension using continuous infusion with angiotensin II.
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 the PAR2 inhibitor AZ3451.
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 (>3-fold) and collagen IV staining (>2-fold). Additional experiments with isolated cardiac fibroblasts showed induction of pro-fibrotic genes when treated with PAR2 inhibitors.
In angiotensin II-induced cardiac injury, PAR2 deficiency has an ambivalent effect, enhancing fibrosis on the one hand, but reducing LVH on the other.
蛋白酶激活受体2（PAR2）的激活已被证明参与包括炎症、纤维化和肥大在内的损伤相关过程的调节。在本研究中，我们将使用血管紧张素II持续输注的高血压小鼠模型，研究PAR2在心脏损伤中的作用。
使用渗透微型泵对12周龄的野生型（wt，n = 8）和PAR2缺陷小鼠（n = 9）持续输注血管紧张素II 4周，诱导高血压。最后，收集心脏，使用组织学、免疫组织学和mRNA表达分析技术分析左心室肥大（LVH）、心肌毛细血管供应、纤维化和PAR2表达的定位。此外，用血管紧张素II处理大鼠心脏成纤维细胞，并用阻断抗体和PAR2抑制剂AZ3451抑制PAR2。
与未处理的对照组相比，用AngII处理的wt小鼠心脏PAR2 mRNA表达下调40±20%。AngII处理4周后，通过相对心脏重量、左心室横截面积和切片上心室腔面积分析确定，与同样处理的PAR2缺陷动物相比，AngII处理的wt小鼠LVH显著增加。wt小鼠的处理导致心脏中FGF23表达增加约3倍，PAR2缺陷动物中的FGF23表达比wt动物低50%，因此与未处理的对照小鼠中的表达水平不再有显著差异。相反，通过天狼星红染色（>3倍）和IV型胶原染色（>2倍）评估，PAR2缺陷小鼠的心脏间质纤维化明显高于类似处理的wt对照。对分离的心脏成纤维细胞进行的额外实验表明，用PAR2抑制剂处理时会诱导促纤维化基因。
在血管紧张素II诱导的心损伤中，PAR2缺陷具有矛盾的作用，一方面增强纤维化，但另一方面减少LVH。
