Gremlin-1 在心肌功能中的保护作用。

Protective role of Gremlin-1 in myocardial function.

机构信息

Department of Cardiology and Angiology, University Hospital, Eberhard Karls University of Tuebingen, Tuebingen, Germany.

Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, Germany.

出版信息

Eur J Clin Invest. 2021 Jul;51(7):e13539. doi: 10.1111/eci.13539. Epub 2021 Mar 17.

DOI:10.1111/eci.13539

PMID:33729579

Abstract

BACKGROUND

Gremlin-1 is a cystine knot protein and is expressed in organs developing fibrosis. Transient ischaemia leads to myocardial fibrosis, a major determinant of impaired myocardial function.

MATERIALS AND METHODS

Expression of Gremlin-1 was investigated in infarcted myocardium by real-time PCR, Western blot analysis, histological and immunohistochemistry staining. We further elaborated the colocalization of Gremlin-1 and TGF-β proteins by confocal microscopy and co-immunoprecipitation experiments. The interaction between Gremlin-1 and TGF-β was analysed by photon correlation spectroscopy. Gremlin-1 modulation of the TGF-β-dependent collagen I synthesis in fibroblasts was investigated using ELISA and immunohistochemistry experiments. The effect of prolonged administration of recombinant Gremlin-1 on myocardial function following ischaemia/reperfusion was accessed by echocardiography and immunohistochemistry.

RESULTS

Gremlin-1 is expressed in myocardial tissue and infiltrating cells after transient myocardial ischaemia (P < .05). Gremlin-1 colocalizes with the pro-fibrotic cytokine transforming growth factor-β (TGF-β) expressed in fibroblasts and inflammatory cell infiltrates (P < .05). Gremlin-1 reduces TGF-β-induced collagen production of myocardial fibroblasts by approximately 20% (P < .05). We found that Gremlin-1 binds with high affinity to TGF-β (K = 54 nmol/L) as evidenced by photon correlation spectroscopy and co-immunoprecipitation. intravenous administration of Gremlin-1-Fc, but not of equivalent amount of Fc control, significantly reduced infarct size by approximately 20%. In the Gremlin-1-Fc group, infarct area was reduced by up to 30% in comparison with mice treated with Fc control (I/LV: 4.8 ± 1.2% vs 6.0 ± 1.2% P < .05; I/AaR: 15.2 ± 1.5% vs 21.1 ± 5%, P < .05).

CONCLUSIONS

The present data disclose Gremlin-1 as an antagonist of TGF-β and presume a role for Gremlin-1/TGF-β interaction in myocardial remodelling following myocardial ischaemia.

摘要

背景

Gremlin-1 是一种半胱氨酸结蛋白，在发生纤维化的器官中表达。短暂性缺血可导致心肌纤维化，这是心肌功能受损的主要决定因素。

材料和方法

通过实时 PCR、Western blot 分析、组织学和免疫组织化学染色来研究 Gremlin-1 在梗死心肌中的表达。我们通过共聚焦显微镜和共免疫沉淀实验进一步阐述了 Gremlin-1 和 TGF-β 蛋白的共定位。通过光子相关光谱分析研究了 Gremlin-1 与 TGF-β 之间的相互作用。使用 ELISA 和免疫组织化学实验研究了 Gremlin-1 对成纤维细胞中 TGF-β 依赖性胶原 I 合成的调节作用。通过超声心动图和免疫组织化学研究了重组 Gremlin-1 延长给药对缺血/再灌注后心肌功能的影响。

结果

短暂性心肌缺血后，Gremlin-1 在心肌组织和浸润细胞中表达（P<.05）。Gremlin-1 与成纤维细胞和炎症细胞浸润中表达的促纤维化细胞因子转化生长因子-β（TGF-β）共定位（P<.05）。Gremlin-1 使心肌成纤维细胞中 TGF-β 诱导的胶原产生减少约 20%（P<.05）。我们发现 Gremlin-1 与 TGF-β 具有高亲和力（K=54nmol/L），这一点通过光子相关光谱和共免疫沉淀得到证实。静脉注射 Gremlin-1-Fc，而不是等效量的 Fc 对照，可使梗死面积减少约 20%。与用 Fc 对照处理的小鼠相比，Gremlin-1-Fc 组的梗死面积减少了高达 30%（I/LV：4.8±1.2%比 6.0±1.2%，P<.05；I/AaR：15.2±1.5%比 21.1±5%，P<.05）。