Abstract
Cardiotoxicity caused by immune checkpoint inhibitors is one of the most severe and potentially fatal side effects. Hence it is crucial from a therapeutic standpoint to understand the underlying processes and devise countermeasures. This study sought to determine whether the SOCS3/JAK/STAT3 signaling pathway, which controls macrophage polarization, contributes to the cardiotoxicity caused by PD-1/PD-L1 inhibitors. The PD-1/PD-L1 inhibitor BMS-1 (10 mg/kg) was used to create a mouse model of immune checkpoint inhibitor-related cardiotoxicity, and hematoxylin and Masson's trichome tests were used to measure cardiomyocyte apoptosis and cardiotoxicity. The production of M1 factors (tumor necrosis factor α [TNF-α] and interleukin [IL]-1 b), as well as the blood levels of myocardial enzymes (creatine kinase, aspartate transaminase, creatine kinase-MB, and lactate dehydrogenase), were evaluated by ELISA. Echocardiography was used to assess the heart's health. The processes were investigated using flow cytometric analysis, real-time PCR, Western blot, and chromatin immunoprecipitation. We found that the PD-1/PD-L1 inhibitor BMS-1 dramatically reduced tumor weight while considerably impairing cardiac function in melanoma-induced tumor-bearing mice. At the gene and protein levels, it was found that levels of SOCS3, JAK, STAT3, and the inflammatory mediators IL-6 and TNF-α had all significantly decreased. Immune checkpoint inhibitor-induced cardiotoxicity may be linked to major changes in the SOCS3/JAK/STAT3 signaling pathway, as indicated by the knockdown of SOCS3, JAK, and STAT3. Finally, immune checkpoint inhibitor intervention demonstrated a large elevation of CD86+ and MHCII+ as well as a considerable increase in macrophages. These data suggest that the SOCS3/JAK/STAT3 signaling pathway, which controls macrophage polarization, may be linked to cardiotoxicity caused by PD-1/PD-L1 inhibitor therapy.