Circulating immune cell signature analysis in HFpEF across species [RNA-Seq - human]

Background: HFpEF is a heterogeneous clinical picture that is closely related to extracardiac comorbidities such as obesity, hypertension and diabetes and is associated with chronic, low-grade systemic inflammation. Previous studies on myocardial biopsies of HFpEF patients showed intramyocardial inflammatory activity, suggesting that the inflammatory processes in HFpEF are predominantly systemic and exhibit compartment specific-patterns. Methods: We performed single cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) of HFpEF patients (n=6), HFrEF patients (n=8) and healthy controls (n=7) taking obesity status into account. For validation, bulk RNA sequencing was performed on whole blood samples. In parallel, the systemic immune cell response was investigated in a HFpEF mouse model (induced by a high-fat diet plus L-NAME), with one group additionally administered the anti-inflammatory agent nitro-oleic acid (NO2-OA). Results: Analysis of human PBMCs revealed a HFpEF-specific inflammatory fingerprint, which manifested in obesity-related increased expression of cytokine signaling genes (e.g. CCL2, TNF) and obesity-independent increases in mitochondrial-associated activity. In the mouse model, HFpEF animals showed a comparable increase in inflammatory markers, with treatment with NO2-OA leading to a partial normalization of immunological signatures and a significant improvement in diastolic function. Conclusion: Our results demonstrate that the immune cells of patients with HFpEF are characterized by a distinct transcriptional immune signature that differs from that of patients with HFrEF. The conserved immunological signatures between humans and mice, and the beneficial effect of NO2-OA in a preclinical model, provide important translational insights and generate hypotheses for personalized interventions in HFpEF. Overall design: Bulk RNA sequencing (RNA-seq.) was performed on PBMCs from healthy human donors which were pre-treated with increasing concentrations of NO2-OA [1 or 3 µM] before induction of inflammation using IL-1ß [10 ng/ml].

背景：射血分数保留型心力衰竭（HFpEF）是一类异质性临床综合征，其与肥胖、高血压、糖尿病等心外合并症密切相关，且伴随慢性低度全身性炎症反应。既往针对HFpEF患者心肌活检的研究显示存在心肌内炎症活性，提示HFpEF的炎症过程主要为全身性，并呈现组织特异性分布模式。
方法：本研究纳入6例HFpEF患者、8例射血分数降低型心力衰竭（HFrEF）患者及7例健康对照者，结合肥胖状态对外周血单个核细胞（PBMCs）进行单细胞RNA测序（scRNA-seq）。为验证结果，我们对全血样本进行了批量RNA测序。同时，在高脂饮食联合L-NAME诱导构建的HFpEF小鼠模型中探究全身性免疫细胞应答情况，其中一组额外给予抗炎药物硝基油酸（NO2-OA）干预。
结果：对人类PBMCs的分析揭示了HFpEF特异性的炎症特征，表现为与肥胖相关的细胞因子信号通路基因（如CCL2、TNF）表达上调，以及与肥胖无关的线粒体相关活性升高。在小鼠模型中，HFpEF模型小鼠的炎症标志物同样出现类似升高，而NO2-OA干预可使免疫特征部分恢复正常，并显著改善舒张功能。
结论：本研究结果表明，HFpEF患者的免疫细胞具有独特的转录组免疫特征，该特征与HFrEF患者存在显著差异。人与小鼠之间保守的免疫特征，以及NO2-OA在临床前模型中的有益作用，为HFpEF的转化研究提供了重要见解，并为其个性化干预策略提出了假说。
整体实验设计：本研究对健康人类供者的PBMCs进行批量RNA测序，这些细胞先用梯度浓度的NO2-OA（1或3 μM）预处理，随后用白细胞介素-1β（IL-1β，10 ng/ml）诱导炎症反应。