[Network pharmacology and molecular docking explore mechanism of Croci Stigma in treating immune checkpoint inhibitor-associated myocarditis].

This study investigated the mechanism of Croci Stigma in treating immune checkpoint inhibitor(ICI)-associated myocarditis based on network pharmacology and molecular docking. Network pharmacology was employed to screen the active ingredients and molecular targets of Croci Stigma in treating ICI-associated myocarditis. The "drug-ingredient-target-disease" network and protein-protein interaction network were constructed to screen the key ingredients and core targets. Gene Ontology functional enrichment analysis showed that the mechanism was related to the regulation of inflammation and apoptosis. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the treatment was related to the advanced glycation end product-receptor for advanced glycation end products(AGE-RAGE) signaling pathway. Molecular docking result showed that crocins had close associations with RAC-alpha serine/threonine-protein kinase 1(AKT1), signal transducer and activator of transcription 3, and matrix metalloproteinase 9. Crocins were then selected as the therapeutic drug. The mouse model of ICI-associated myocarditis was established by subcutaneous injection of porcine cardiac myosin combined with intraperitoneal injection of pembrolizumab. The results suggested that Croci Stigma reduced the spleen index but had no effect on the heart index. The electrocardiogram showed that Croci Stigma increased the heart rate and shortened PR and QRS intervals. Echocardiographic data indicated that Croci Stigma increased the left ventricular stroke volume, cardiac output, ejection fraction, and fractional shortening. Hematoxylin-eosin and Masson staining results showed that Croci Stigma decreased the number of inflammatory cells infiltrating in the myocardium and alleviated myocardial fibrosis. Enzyme-linked immunosorbent assay results showed that Croci Stigma decreased the serum levels of inflammatory cytokines including tumor necrosis factor-alpha, interleukin-6, interleukin-12, and regulated on activation, normal T-cell expressed and secreted and lowered the levels of creatine kinase and creatine kinase isoenzyme MB. Biochemical data suggested that Croci Stigma inhibited the activities of superoxide dismutase and lactate dehydrogenase. Western blot result showed that Croci Stigma regulated the expression of myocardial AKT. The findings demonstrate that Croci Stigma may regulate AKT expression to effectively protect the cardiac tissue from ICI-associated myocarditis through antagonizing immune responses and inflammation, inhibiting oxidative stress, alleviating cardiac fibrosis, relieving cardiac block, and improving the cardiac function.