N-acetylcysteine stimulates organelle malfunction in endometriotic cells via IFN-gamma signaling

Endometriosis is a chronic inflammatory gynecologic disease characterized by the abnormal implantation of endometrial tissue outside the uterus. The inflammatory microenvironment of endometriosis is dominated by highly migratory endometriotic cells, inflammatory cells, and cytokines. There is no curative treatment other than oral contraceptives, painkillers, and surgery. N-acetyl-L-cysteine (NAC), an anti-inflammatory compound has been identified as a promising agent for endometriosis. However, it is still unclear how NAC interacts with interferon-gamma (IFN-ɣ) and common cytokines in the endometriotic microenvironment. This study aimed to investigate the effects of NAC, alone and in combination with IFN-ɣ and major cytokines such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-⍺) on endometriotic cells. For this purpose, we performed a real time-dependent cell impedance assay, Annexin V/PI and ER tracking by flow cytometry, immunofluorescence, western blotting, and metabolomic assays. Our results offered a new insight into the complex relationship between NAC and IFN-ɣ, both of which reduced endometriotic cells' proliferation, induced ER stress and mitochondrial dysfunction. In conclusion, NAC and IFN-ɣ, alter the metabolism of endometriotic cells, leading to endoplasmic reticulum stress and mitochondrial dysfunction. These findings suggest that NAC when combined with IFN-ɣ, has the potential to generate innovative therapeutic modalities for the treatment of endometriosis.