Nanoplastics causes heart aging/myocardial cell senescence through the Ca2+/mtDNA/cGAS-STING signaling cascade

Nanoplastics (NPs) are now a new class of pollutants widely present in the soil, atmosphere, freshwater and marine environments. Nanoplastics can rapidly penetrate cell membranes and accumulate in human tissues and organs, thus posing a potential threat to human health. The heart is the main power source of the body. But up to now, the toxicological effects of long-term exposure to nanoplastics on the heart has not been revealed yet. We evaluated the effects of long term exposure of nanoplastics on cardiac cell/tissue in vitro and in vivo model. Furthermore, we explored the molecular mechanism by which nanoplastics exposure causes myocardial cell senescence. Immunohistochemistry, indirect immunofluorescence and ELISA were performed to detect the effects of nanoplastics on heart aging. We found that nanoplastics were able to induce significant cardiac aging through a series of biochemical assays in vivo. In vitro, the effects of nanoplastics on cardiac cell were investigated, and found that nanoplastics were able to internalize into cardiomyocytes in time and dose-dependant manner. Further biochemical analysis showed that nanoplastics induces cardiomyocytes senescence by detecting a series of senescence marker molecules. Molecular mechanism research shows that nanoplastics may cause mitochondrial destabilization by inducing oxidative stress, which leads to the leakage of mtDNA from mitochondria into the cytoplasm, and then cytoplasm-localized mt-DNA activates the cGAS-STING signaling pathway and promotes inflammation response, ultimately inducing cardiomyocytes senescence. In this work, we found that nanoplastics exposure induces premature aging of heart. Current research also reveals the molecular mechanism by which nanoplastics induces cardiomyocyte senescence. This study laid the foundation for further studying the potential harm of nanoplastics exposure on heart.