The Release of Peripheral Immune Inflammatory Cytokines Promote an Inflammatory Cascade in PCOS Patients via Altering the Follicular Microenvironment

Abstract

BackgroundHormones and immune imbalance are critical factors in polycystic ovary syndrome (PCOS). The alternation of immune microenvironment of oocytes may play a significant role in infertility of PCOS patients.ObjectiveThis study explores the role of follicular fluid microenvironment change in inflammatory pathways activation of granulosa cells (GCs) in PCOS women infertility.MethodsWe enrolled 27 PCOS patients and 30 controls aged 22 to 38 years who underwent IVF and collected their luteinized granulosa cells (LGCs). Meanwhile, a granulosa-like tumor cell line (KGN) as a cell-model assisted this study. Key inflammatory markers in human ovarian GCs and follicular fluid were detected by RT-qPCR, Western blotting, or ELISA. The KGN cells were treated with follicle supernatant mixed with normal medium to simulate the microenvironment of GCs in PCOS patients, and the inflammation indicators were observed. The assembly of NLRP3 inflammasomes was detected by immunofluorescence techniques. Dihydroethidium assay and EdU proliferation assay were used to detect ROS and cell proliferation by flow cytometry.ResultsCompared with normal controls (n = 19), IL-1β (P = 0.0005) and IL-18 (P = 0.021) in the follicular fluid of PCOS patients (n = 20) were significantly increased. The NF-κB pathway was activated, and NLRP3 inflammasome was formatted in ovarian GCs of PCOS patients. We also found that inflammation of KGN cells was activated with LPS irritation or stimulated by follicular fluid from PCOS patients. Finally, we found that intracellular inflammation process damaged mitochondrial structure and function, which induced oxidative stress, affected cellular metabolism, and impaired cell proliferation.ConclusionInflammatory microenvironment alteration in the follicular fluid of PCOS patients leads to activated inflammatory pathway in GCs, serving as a crucial factor that causes adverse symptoms in patients. This study provides a novel mechanism in the inflammatory process of PCOS.

Polycystic Ovary Syndrome: A Comprehensive Review of Pathogenesis, Management, and Drug Repurposing

“…Appropriate inflammation is a vital cause of oocyte growth and ovulation [ 66 ]. However, high levels of white blood cell [ 46 , 66 ], C-reactive protein (CRP) [ 4 , 46 , 50 , 66 , 67 ], and other inflammatory biomarkers in peripheral blood are associated with PCOS [ 4 , 46 , 66 , 67 , 68 ]. Inflammation is a cause of HA [ 44 , 69 ].…”

“…Furthermore, IL-1 hinders the FSH and LH receptors. Inhibition of these receptors leads to inhibition of follicular development and ovulation [ 66 ]. Both TNF-α and IL-1β inhibit activation of HNF-4α by different mechanisms [ 23 ].…”

“…Both TNF-α and IL-1β inhibit activation of HNF-4α by different mechanisms [ 23 ]. In addition, NLRP3 inflammasomes induce follicular pyroptosis, ovarian fibrosis, and disturbance of follicular formation [ 66 ]. An increase in CRP level is another cause of IR in insulin-sensitive tissues.…”

“…CRP stimulates this increase in secretion [ 72 ]. Moreover, another study approved the higher-than-normal level of IL-6 mRNA in granulosa cells [ 66 ].…”

MiR-1224-5p attenuates polycystic ovary syndrome through inhibiting NOD-like receptor protein 3 inflammasome activation via targeting Forkhead box O 1

“…Non-esterified fatty acid induced NLRP3 inflammasome activation in GCs [ 12 ]. Notably, compared with normal controls, NLRP3 inflammasome was formatted/activated in ovarian GCs of PCOS patients and in KGN cells stimulated by LPS or follicular fluid from PCOS patients [ 13 ]. Although the activation of NLRP3 inflammasome is detected in patients with PCOS [ 14 ], the underlying regulatory mechanism remains largely unknown.…”