Mechanical stress attenuates the metabolic reprogramming and M1 polarization of macrophages by upregulating integrin subunit alpha D.

We previously demonstrated that a novel growth-friendly system can alleviate pulmonary hypoplasia in piglets with early-onset scoliosis combined with thoracic insufficiency syndrome (EOS + TIS) by improving the mechanical microenvironment. Transcriptomic analyses indicated that mechanical stress (MS) may exert its effects by regulating immune responses and metabolic pathways. Building upon this foundation, the present study further investigates the implications of MS on macrophage polarization and metabolic reprogramming, as well as the underlying molecular mechanisms. In this study, MS at a 10% amplitude effectively downregulated M1-type markers (CD86, IL-1β, iNOS, TNF-α) in RAW264.7 cells, while upregulating M2-type markers (TGF-β, CD206, IL-10). Transcriptomic analysis further suggested that MS influences lung development by regulating glycolysis, metabolic reprogramming, and immune-related pathways. Further experiments demonstrated that the MS downregulated glycolytic enzymes (PKM2, GLUT1, PGK1, and LDHA), reduced lactate production and extracellular acidification rate, while enhancing oxygen consumption rate and promoting the tube-forming capacity of human umbilical vein endothelial cells, induced by conditioned media from RAW264.7 cells. Mechanistically, MS activated the SOCS3/STAT3 pathway by upregulating Integrin Subunit Alpha D (ITGAD) expression, thereby facilitating M2 polarization and suppressing glycolytic metabolic reprogramming in RAW264.7 cells. ITGAD knockdown reversed these implications. In conclusion, MS activates the SOCS3/STAT3 pathway by upregulating ITGAD, thereby promoting macrophage polarization toward the M2 phenotype, suppressing glycolytic metabolic reprogramming, and enhancing their pro-angiogenic function. This discovery reveals a novel mechanism of MS in the pulmonary microenvironment, providing a new molecular perspective for understanding the pathological processes of EOS + TIS-associated pulmonary dysplasia.