Roundup® Induces Premature Senescence of Mouse Granulosa Cells Via Mitochondrial ROS-triggered NLRP3 Inflammasome Activation

Roundup, a glyphosate-based herbicide widely used in agriculture, has raised concerns regarding its potential impact on human health due to the detection of its residues in human urine and serum. Granulosa cells are essential for oocyte growth and follicle development. Previous research has shown that Roundup could affect steroid synthesis, increases oxidative stress, and induces apoptosis in granulosa cells. However, little is known about the effects of Roundup on NLRP3 (nucleotide binding oligomerization domain-like receptor family pyrin-containing domain protein 3) inflammasome activation and cellular senescence in granulosa cells. Here, we provided evidence that exposure to Roundup induced premature senescence in mouse granulosa cells through the activation of NLRP3 inflammasome triggered by mitochondrial ROS. Our findings demonstrated that Roundup significantly reduced the viability of granulosa cells under in vitro culture conditions. It also disrupted mitochondrial function and induced oxidative stress in these cells. Subsequent investigations showed that NLRP3 inflammasome was activated in treated granulosa cells, as evidenced by the upregulation of inflammasome-related genes and the processing of inflammatory cytokines IL-1β and IL-1α into their mature forms. Consequently, premature cellular senescence occurred in response to the challenge posed by Roundup. Notably, direct inhibition of NLRP3 inflammasome with MCC950 does not alleviate mitochondrial damage and oxidative stress. However, supplementation of resveratrol, which has been known to attenuate mitochondrial damage and oxidative stress, effectively mitigated the inflammatory response and the expression of senescence-related markers, and prevented the senescence in granulosa cells. These results suggested that mitochondrial function and oxidative homeostasis might play pivotal roles as upstream regulators of NLRP3 inflammasome. In summary, our findings indicated that the premature senescence of granulosa cells caused by mitochondrial ROS-triggered NLRP3 inflammasome activation might contribute to the ovarian toxicity of Roundup, in addition to its known effects on steroidogenesis and apoptosis.