Microfluidic Modeling of Macrophage-Induced Cardiac Inflammation Using NF-κB Reporter Cardiomyocytes

Inflammation is a key driver of cardiac disease progression, including heart failure and myocardial infarction, with macrophage-cardiomyocyte interactions playing a central role in shaping the local inflammatory microenvironment. Prolonged exposure to pro-inflammatory cytokines, many produced by macrophages, induces cardiomyocyte stress, dysfunction, and pathological tissue remodeling. However, the spatial and temporal dynamics of this crosstalk remain poorly understood, limiting the development of targeted therapies. To address this gap, we developed an in vitro cardiac inflammation model that enables controlled investigation of macrophage-cardiomyocyte interactions. Cardiomyocytes were transduced with an NF-κB-responsive fluorescent reporter to allow real-time monitoring of inflammatory signaling. MATLAB-based simulations were used to optimize medium delivery and cell densities by modeling TNFα diffusion. Using a multiplex microfluidic co-culture chip, we identified the TNFα threshold of 50 ng mL^{- 1} with a 6-h exposure as sufficient to activate cardiomyocyte NF-κB signaling. Both macrophage-conditioned medium and direct co-culture significantly increased NF-κB activation, indicating enhanced cardiomyocyte inflammatory stress. Dexamethasone markedly suppressed NF-κB activation when administered at onset of co-culture to both cell types, whereas IL-10 showed limited efficacy. Overall, this cardiac inflammation model provides a versatile platform for dissecting immune-cardiac crosstalk and supports future studies of multicellular crosstalk, spatiotemporal signaling dynamics, and therapeutic screening.