Background Cardiac fibrosis, marked by excessive extracellular matrix deposition, is a common outcome of ischemia, inflammation, or neurohormonal activation. In cancer patients undergoing thoracic radiotherapy, radiation-induced fibrosis remains a major concern. BNIP3, a BCL2 family protein involved in mitochondrial stress responses, has been implicated in cardiomyocyte damage and adverse remodeling. It promotes mitochondrial depolarization and autophagy, processes also triggered by radiation exposure. Recent studies suggest that BNIP3 inhibition may attenuate apoptosis and fibrosis in cardiac disease models. However, its role in radiation-induced cardiac injury is not yet fully understood. Targeting BNIP3 may therefore offer a novel approach to reduce radiotherapy-associated cardiac damage.
Methods & Results In the preliminary phase of our study, HCAEC cells were selected for in vitro analysis. The xCELLigence real-time cell analysis (RTCA) system was used to evaluate the effects of the BNIP3-targeted peptide antagonist on cell proliferation and cytotoxicity. Following treatment with various peptide concentrations (0.1, 1, 5, 10, 20, 50, and 100 μM), the half-maximal inhibition concentration (IC₅₀) was determined to be 30.4 μM.
To explore the time-dependent effects of peptide–radiation interactions, as well as the cytotoxic impact of radiation and the therapeutic potential of the BNIP3-targeted antagonist, a series of immunohistochemical analyses were conducted. Cells were treated with the peptide at various time points relative to irradiation (24, 6, 2 and 0.5 hours before irradiation; and 0.5, 2, 6, and 24 hours after irradiation). Immunostaining was subsequently performed for LC3B and p62 (autophagy markers), γ-H2AX (DNA damage marker), and Cleaved Caspase-3 (apoptosis marker). In addition, qRT-PCR analyses of genes associated with autophagy and apoptosis suggested that the BNIP3 pathway may represent a key target for mitigating radiation-induced cardiac injury. Preliminary results indicate that the BNIP3-targeted peptide modulates autophagy, DNA damage, and apoptosis signaling, particularly in response to radiation exposure.
Conclusion Our initial findings suggest that modulation of BNIP3 pathway may influence autophagy, DNA damage, and apoptosis pathways in response to radiation. Further analysis is needed to clarify its potential role and underlying mechanisms.
