GLUT1 Mediates the Metabolic Reprogramming and Inflammation of CCR2$^+$ Monocytes/Macrophages from Patients with DCM

Macrophages expressing CC chemokine receptor 2 (CCR2) possess characteristics and performance akin to M1 polarized macrophages, which promote inflammation. Advanced heart failure (HF) patients with higher abundance of CCR2+ macrophages are more likely to experience adverse remodeling. The precise mechanism of CCR2+ macrophages in how they affect the progression of dilated cardiomyopathy remains unknown.

Cardiac biopsy samples from dilated cardiomyopathy patients (DCM) were used for immunohistochemistry and immunofluorescence staining. PCR is employed to identify the IL-1β, IL-6, TNF-α, TGF-β, MMP2, MMP9, PKM1, PKM1, GLUT1, GLUT2, GLUT3, GLUT4, PDK1, PFKFB3, PFK1 and HK2 mRNA expression of CCR2+ monocytes/macrophages from the peripheral blood of DCM patients. Seahorse was used to evaluate the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) of CCR2+ monocytes/macrophages. 2-DG was used to simulate a lack of glucose. Lentivirus containing GLUT1 inhibitory sequence was used to knockdown GLUT1 gene expression of CCR2+ monocytes/macrophages. Western Blot and immunofluorescence staining was used to evaluate the expression of NLRP3.

Immunostaining results of cardiac biopsy tissue from dilated cardiomyopathy (DCM) patients demonstrated that the progression to HF was associated with an increase in the number of CCR2+ macrophages. PCR results demonstrated that CCR2 monocytes and macrophages derived from the blood of DCM patients expressed elevated levels of inflammatory factors and up regulation of glycolysis related genes. In addition, OCR and glucose uptake experiments confirmed that increased glucose uptake of these cells was associated with greater inflammation and correlated with a worsening of cardiac function. limiting the glucose supply to CCR2+ monocytes and macrophages, or suppressing the activity of glucose transporter 1 (GLUT1) could reduce inflammation levels.

These results suggest that CCR2+ monocytes and macrophages rely on metabolic reprogramming to trigger inflammatory response and contribute to myocardial injury and the progression of DCM.