Department of Laboratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, China.
Department of Laboratory Medicine, Jiangning Hospital Affiliated to Nanjing Medical University, Nanjing, China.
Immun Inflamm Dis. 2024 Apr;12(4):e1237. doi: 10.1002/iid3.1237.
Severe myocarditis is often accompanied by cardiac fibrosis, but the underlying mechanism has not been fully elucidated. CXCL4 is a chemokine that has been reported to have pro-inflammatory and profibrotic functions. The exact role of CXCL4 in cardiac fibrosis remains unclear.
Viral myocarditis (VMC) models were induced by intraperitoneal injection of Coxsackie B Type 3 (CVB3). In vivo, CVB3 (100 TCID50) and CVB3-AMG487 (CVB3: 100 TCID50; AMG487: 5 mg/kg) combination were administered in the VMC and VMC+AMG487 groups, respectively. Hematoxylin and eosin staining, severity score, Masson staining, and immunofluorescence staining were performed to measure myocardial morphology in VMC. Enzyme-linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were performed to quantify inflammatory factors (IL-1β, IL-6, TNF-α, and CXCL4). Aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase-myocardial band (CK-MB) levels were analyzed by commercial kits. CXCL4, CXCR3B, α-SMA, TGF-β1, Collagen I, and Collagen III were determined by Western blot and immunofluorescence staining.
In vivo, CVB3-AMG487 reduced cardiac injury, α-SMA, Collagen I and Collagen III levels, and collagen deposition in VMC+AMG487 group. Additionally, compared with VMC group, VMC+AMG group decreased the levels of inflammatory factors (IL-1β, IL-6, and TNF-α). In vitro, CXCL4/CXCR3B axis activation TGF-β1/Smad2/3 pathway promote mice cardiac fibroblasts differentiation.
CXCL4 acts as a profibrotic factor in TGF-β1/Smad2/3 pathway-induced cardiac fibroblast activation and ECM synthesis, and eventually progresses to cardiac fibrosis. Therefore, our findings revealed the role of CXCL4 in VMC and unveiled its underlying mechanism. CXCL4 appears to be a potential target for the treatment of VMC.
重症心肌炎常伴有心肌纤维化，但发病机制尚未完全阐明。趋化因子（CXCL4）具有促炎和促纤维化作用。然而，CXCL4 在心肌纤维化中的确切作用尚不清楚。
通过腹腔注射柯萨奇 B 型 3（CVB3）诱导病毒性心肌炎（VMC）模型。体内实验中，将 CVB3（100TCID50）和 CVB3-AMG487（CVB3：100TCID50；AMG487：5mg/kg）分别给予 VMC 组和 VMC+AMG487 组。采用苏木精-伊红染色、严重程度评分、马松染色和免疫荧光染色观察心肌形态学变化。酶联免疫吸附试验（ELISA）和实时定量聚合酶链反应（qRT-PCR）检测炎症因子（IL-1β、IL-6、TNF-α和 CXCL4）水平。采用商业试剂盒分析天门冬氨酸氨基转移酶（AST）、乳酸脱氢酶（LDH）和肌酸激酶同工酶-MB（CK-MB）水平。采用 Western blot 和免疫荧光染色检测 CXCL4、CXCR3B、α-SMA、TGF-β1、Collagen I 和 Collagen III。
体内实验中，CVB3-AMG487 降低了 VMC+AMG487 组的心肌损伤、α-SMA、Collagen I 和 Collagen III 水平以及胶原沉积。与 VMC 组相比，VMC+AMG 组降低了炎症因子（IL-1β、IL-6 和 TNF-α）水平。体外实验中，CXCL4/CXCR3B 轴激活 TGF-β1/Smad2/3 通路促进小鼠心肌成纤维细胞分化。
CXCL4 作为 TGF-β1/Smad2/3 通路诱导的心肌成纤维细胞活化和 ECM 合成中的促纤维化因子，最终导致心肌纤维化。因此，我们的研究结果揭示了 CXCL4 在 VMC 中的作用及其潜在机制。CXCL4 似乎是治疗 VMC 的潜在靶点。
