Abstract
In hypertrophic scar (HS) formation, the type 2 immune response induces the alternatively activated macrophages (M2), which manipulate fibroblasts to differentiate into myofibroblasts with active biologic functions and proliferation. Myofibroblasts express α-smooth muscle actin (α-SMA) and synthesize and produce additional collagen type I and collagen type III, inducing HS formation. However, studies on the mechanism of M2 macrophage modulation are only based on the recognition of profibrotic factors such as TGF-β1 secreted by macrophages. The influence of exosomes from M2 macrophages on scar formation is still unknown. Both M2 macrophages and myofibroblasts highly express glutaminases (GLSs). GLS is a critical enzyme in glutaminolysis and is important for M2 macrophage and fibroblast polarization. In this study, we found that in a TGF-β1-stimulated coculture system, a long noncoding RNA (lncRNA) named lncRNA-ASLNCS5088 was enriched in M2 macrophage-derived exosomes. This lncRNA could be transferred with high efficiency to fibroblasts and acted as an endogenous sponge to adsorb microRNA-200c-3p, resulting in increased GLS and α-SMA expression. Pretreatment with GW4869, which impairs M2 macrophage exosome synthesis, ameliorated these pathologic changes in fibroblasts in vitro. Local injection in the late scar formation period with GW4869 reduced α-SMA+ fibroblasts and alleviated the fibrosis of tissue after wound healing in vivo.-Chen, J., Zhou, R., Liang, Y., Fu, X., Wang, D., Wang, C. Blockade of lncRNA-ASLNCS5088-enriched exosome generation in M2 macrophages by GW4869 dampens the effect of M2 macrophages on orchestrating fibroblast activation.