Inflammation, fibrosis and metabolic stress critically promote heart failure with preserved ejection fraction (HFpEF). Exposure to high-fat diet and nitric oxide synthase inhibitor N[w]-nitro-l-arginine methyl ester (L-NAME) recapitulate features of HFpEF in mice. To identify disease-specific traits during adverse remodeling, we profiled interstitial cells in early murine HFpEF using single-cell RNAseq (scRNAseq). Diastolic dysfunction and perivascular fibrosis were accompanied by an activation of cardiac fibroblast and macrophage subsets. Integration of fibroblasts from HFpEF with two murine models for heart failure with reduced ejection fraction (HFrEF) identified a catalog of conserved fibroblast phenotypes across mouse models. Moreover, HFpEF-specific characteristics included induced metabolic, hypoxic and inflammatory transcription factors and pathways, including enhanced expression of Angiopoietin-like 4 (Angptl4) next to basement membrane compounds, such as collagen IV (Col4a1). Fibroblast activation was further dissected into transcriptional and compositional shifts and thereby highly responsive cell states for each HF model were identified. In contrast to HFrEF, where myofibroblast and matrifibrocyte activation were crucial features, we found that these cell states played a subsidiary role in early HFpEF. These disease-specific fibroblast signatures were corroborated in human myocardial bulk transcriptomes. Furthermore, we identified a potential cross-talk between macrophages and fibroblasts via SPP1 and TNFɑ with estimated fibroblast target genes including Col4a1 and Angptl4. Treatment with recombinant ANGPTL4 ameliorated the murine HFpEF phenotype and diastolic dysfunction by reducing collagen IV deposition from fibroblasts in vivo and in vitro. In line, ANGPTL4, was elevated in plasma samples of HFpEF patients and particularly high levels associated with a preserved global-longitudinal strain. Taken together, our study provides a comprehensive characterization of molecular fibroblast activation patterns in murine HFpEF, as well as the identification of Angiopoietin-like 4 as central mechanistic regulator with protective effects.

炎症、纤维化和代谢应激严重促进射血分数保留的心力衰竭 （HFpEF）。暴露于高脂肪饮食和一氧化氮合酶抑制剂 N[w]-硝基-l-精氨酸甲酯 （L-NAME） 概括了小鼠 HFpEF 的特征。为了确定不良重塑过程中的疾病特异性状，我们使用单细胞 RNAseq （scRNAseq） 分析了早期小鼠 HFpEF 中的间质细胞。舒张功能障碍和血管周围纤维化伴有心脏成纤维细胞和巨噬细胞亚群的激活。将 HFpEF 的成纤维细胞与两个射血分数降低的心力衰竭 （HFrEF） 小鼠模型整合，确定了小鼠模型中保守的成纤维细胞表型目录。此外，HFpEF 特异性特征包括诱导代谢、缺氧和炎症转录因子和途径，包括血管生成素样 4 （Angptl4） 在基底膜化合物（如胶原蛋白 IV （Col4a1））旁边的表达增强。成纤维细胞活化进一步分解为转录和组成变化，从而确定了每个 HF 模型的高反应性细胞状态。与肌成纤维细胞和基质纤维细胞活化是关键特征的 HFrEF 相比，我们发现这些细胞状态在早期 HFpEF 中起辅助作用。这些疾病特异性成纤维细胞特征在人心肌大量转录组中得到证实。此外，我们通过 SPP1 和 TNFɑ 鉴定了巨噬细胞和成纤维细胞之间潜在的串扰，估计成纤维细胞靶基因包括 Col4a1 和 Angptl4。用重组ANGPTL4处理通过减少体内和体外成纤维细胞的胶原蛋白 IV 沉积来改善小鼠 HFpEF 表型和舒张功能障碍。 在 HFpEF 患者的血浆样本中，ANGPTL4 升高，特别是与保留的整体纵向应变相关的高水平。综上所述，我们的研究提供了小鼠 HFpEF 中分子成纤维细胞活化模式的全面表征，以及血管生成素样 4 作为具有保护作用的中心机制调节因子的鉴定。