CD147 is associated with NF-κB activation during the post-traumatic immune response in a murine trauma model

Abstract Extracellular matrix metalloproteinase inducer (CD147) has been proven to play a crucial role in a variety of inflammatory diseases but has not yet been investigated in trauma. The aim of the study was to investigate the role of CD147 in a murine model of trauma and hemorrhagic shock (TH) on the activation of NF-κB, as a central pro-inflammatory transcription factor. Moreover, we investigated the effect of 17β-estradiol (E2) on inflammatory pathways. Fifty male C57/BL6 mice were randomized into five groups (Control, TH, Sham, TH + E2, Sham+E2). Intervention groups received 2 µg/g E2 and suffered TH (femur fracture and pressure-controlled shock for 90 min). Sacrifice and organ harvesting for further analyses were performed 24 h post trauma. Liver ischemia-reperfusion injury was assessed using Suzuki’s liver injury score on histological samples. Kupffer cells (KCs) were isolated from liver tissue for ex vivo analyses. Profiles of inflammatory mediators, including CD147, were generated from plasma and supernatant of the KC culture. Extracellular vesicles were isolated from plasma and supernatant of the KC culture and analyzed. Furthermore, in an in vitro approach, a RAW 264.7 macrophage cell line was used to test whether recombinant (rm)CD147 had the potential to phosphorylate the p65 subunit of NF-κB and whether E2 modulates the rmCD147-p65 interaction. TH animals showed higher CD147 concentrations in plasma, in KC-derived extracellular vesicles, as well as in cell supernatant of ex vivo KCs ( p < 0.05). RmCD147 was able to induce the phosphorylation of the p65 subunit of NF-κB in vitro ( p < 0.05). E2 therapy significantly reduced the Suzuki’s liver injury score values in the TH-E2 group and normalized the cytokine profile, including CD147 concentrations. In the in vitro experiments, co-incubation with E2 dampened the phosphorylating effect of CD147 on the p65 subunit of NF-κB. In conclusion, our study identified CD147 as a proinflammatory mediator associated with activation of the NF-κB pathway. Recombinant CD147 promoted p65 phosphorylation in macrophages, whereas estradiol attenuated this response. Further mechanistic studies (e.g. knock-out models) are required to determine the causal contribution of CD147 signaling to post-traumatic inflammation.