GLUT-1/PKM2 loop dysregulation in patients with non-ST-segment elevation myocardial infarction promotes metainflammation

Aims The functional capacity of the immune cells is strongly dependent on their metabolic state and inflammatory responses are characterized by a greater use of glucose in immune cells. This study is aimed to establish the role of glucose metabolism and its players [glucose transporter 1 (GLUT-1) and pyruvate kinase isozyme M2 (PKM2)] in the dysregulation of adaptive immunity and inflammation observed in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Methods and results We enrolled 248 patients allocated to three groups: NSTEMI patients, chronic coronary syndromes (CCS) patients, healthy subjects (HSs). NSTEMI patients showed higher expression of GLUT-1 and an enhanced glucose uptake in T cells when compared with CCS patients (P < 0.0001; P = 0.0101, respectively) and HSs (P = 0.0071; P = 0.0122, respectively). PKM2 had a prevalent nuclear localization in T lymphocytes in NSTEMI (P = 0.0005 for nuclear vs. cytoplasm localization), while in CCS and HS, it was equally distributed in both compartments. In addition, the nuclear fraction of PKM2 was significantly higher in NSTEMI compared with HS (P = 0.0023). In NSTEMI patients, treatment with Shikonin and Fasentin, which inhibits PKM2 enzyme activity and GLUT-1-mediated glucose internalization, respectively, led to a significant reduction in GLUT-1 expression along with the down-regulation of pro-inflammatory cytokine expression. Conclusion NSTEMI patients exhibit dysregulation of the GLUT-1/PKM2 metabolic loop characterized by nuclear translocation of PKM2, where it acts as a transcription regulator of pro-inflammatory genes. This detrimental loop might represent a new therapeutic target for personalized medicine.

Automated summary

The role of glucose metabolism and its players, GLUT-1 and PKM2, in the dysregulation of adaptive immunity and inflammation observed in NSTEMI patients was investigated. NSTEMI patients exhibited higher expression of GLUT-1 and increased glucose uptake in T cells compared to CCS patients and healthy subjects. PKM2 had a nuclear localization in NSTEMI patients, while it was equally distributed in both compartments in CCS patients and healthy subjects. Inhibition of PKM2 enzyme activity and GLUT-1-mediated glucose internalization led to a significant reduction in GLUT-1 expression and down-regulation of pro-inflammatory cytokines in NSTEMI patients.