Several retrospective studies reported PCOS as one of the most common comorbidities of COVID-1936. However, why PCOS patients are susceptible to COVID-19 remains uncertain. Therefore, understanding the molecular mechanisms, early diagnosis, and intervention is of great clinical importance. In this work, we performed bioinformatics analyses on two independent gene chip databases containing SARS-CoV-2 infected NHBE and PCOS granulosa cells and identified 27 common DEGs.According to GO, KEGG, and GSEA enrichment analysis, the DEGs were enriched primarily in immune response, NF-kappaB transcription factor activity regulation, Toll-like receptor (TLR) binding, virus infection, TNF signaling pathway, IL-17 signaling pathway, and NOD-like receptor signaling pathway. These findings suggest that COVID-19 and PCOS have DEGs associated with inflammation and immune response. It has also been reported that severe COVID-19 triggers an exaggerated inflammatory response that can lead to acute respiratory distress syndrome, a life-threatening condition associated with multi-organ failure and high mortality37. By Pearson correlation analysis, we found that 7 hub genes were significantly positively correlated with immune scores, implying that they are associated with immune infiltration. Hub gene expression heatmaps showed that hub gene expression was low in innate immune cells such as monocytes, activated NK cells, and neutrophils. Most of the hub genes had lower expression in M2 macrophages, whereas they were highly expressed in M1 macrophages. As is well known, M2 macrophages suppress inflammation while M1 macrophages promote it38. The differential expression of hub genes in macrophages may be a common pathogenic cause of PCOS and SRAS-Cov-2. Furthermore, in the training set, validation set, animal models, and clinical samples, the expression of hub genes was significantly higher in the PCOS and SARS-Cov-2 groups than in the control group. This suggests that high expression of these genes is associated with the development of inflammation. Recent findings have indicated that the periovulatory follicles of women with PCOS contain elevated inflammatory mediators and that this low-grade inflammation might serve as a precursor to ovarian dysfunction in PCOS39. This underlying proinflammatory predisposition may put women with PCOS at increased risk of severe COVID-1914.Based on the MCODE and seven algorithms of CytoHubba, we screened seven hub genes, including S100A9, TLR2, CD86, ICAM, THBD, MMP9, and ITGB2. This study will focus on the effects of these hub genes on PCOS and COVID-19 from an inflammatory perspective. TLR2 was a key hub gene among the hub genes. During a viral infection, the host uses pattern recognition receptors, especially TLRs, to sense the virus and activate the innate immune system40. TLR2 was thought to be one of the most significant members of the TLR family and is responsible for sustaining airway inflammation41. In line with this, GO, and KEGG Pathway identified significant enrichment in signaling pathways involving toll-like receptors. In addition, COVID-19 severity was associated with TLR2 expression. Coronavirus infection caused proinflammatory cytokines to be produced independently of viral entry via TLR2-dependent signaling. TLR2 sensed the SARS-CoV-2 envelope protein as its ligand42,43. Besides, there was evidence that TLRs are located in ovary granulosa cells, cumulus cells, and theca cells44. The abnormal expression of TLRs did not result in good oocyte quality and insufficient fertility45. In another study, TLR2 was found to be highly expressed in granulosa cells from PCOS patients and could mediate inflammation and oxidative stress caused by LPS46. These results showed that TLR2 was a key molecule mediating inflammation in COVID-19 and PCOS. We speculate that the state of chronic inflammation in PCOS primarily mediates the susceptibility of affected patients to COVID-19. Other hub genes were also associated with inflammatory pathways or metabolic pathways, which were involved in PCOS and became potential risk factors for susceptibility to COVID-1947,48,49.S100A9, also known as calgranulin B, is a proinflammatory protein implicated in various inflammatory disorders50. S100A9 is posited to exacerbate the inflammatory state within this disorder, intensifying metabolic dysfunction and reproductive anomalies51,52. Elevated S100A9 levels have been associated with increased adipose tissue inflammation and insulin resistance—hallmarks of PCOS53. Meanwhile, S100A9 was found to be upregulated in PCOS samples by dataset analysis, clinical samples, and animal model assays in this study. These findings suggest that S100A9 not only contributes to the inflammatory environment but may also serve as a therapeutic target to alleviate the metabolic and reproductive complications of PCOS. In the context of COVID-19, S100A9 appears to play a detrimental role by intensifying inflammatory responses, potentially leading to severe lung injury and systemic complications. The protein’s overexpression in severe COVID-19 cases correlates with elevated cytokine levels, enhanced neutrophil infiltration, and worse clinical outcomes50,54. These observations indicate that S100A9 could act both as a biomarker of disease severity and as a target for therapeutic intervention to modulate the inflammatory response in COVID-19 patients. Specifically, women with PCOS who contract COVID-19 could face more severe manifestations due to pre-existing chronic inflammation and metabolic dysregulation, potentially mediated by elevated S100A9 levels. Trials exploring inhibitors of S100A9 or its signaling pathways could elucidate strategies to reduce the inflammatory burden in these patients, potentially improving symptoms and outcomes for both PCOS and COVID-19.CD86, also known as B7-2 or B70, plays a pivotal role as a co-stimulatory molecule involved in immune regulation, particularly in antigen presentation and T-cell activation55. CD86 is prominently expressed on antigen-presenting cells such as dendritic cells and macrophages, which are crucial for activating T cells via interactions with CD2856. This interaction perpetuates inflammatory responses observed in PCOS, potentially exacerbating insulin resistance and ovarian dysfunction. Elevated CD86 expression correlates with conditions marked by chronic inflammation, underscoring its likely involvement in the pathogenesis of PCOS57. Consistent with this, this study also found elevated expression of CD86 in PCOS samples. In the context of COVID-19, CD86 is implicated in the dysregulated immune responses observed in severe cases of the disease. Dysregulated immune activation, including excessive co-stimulatory signaling pathways like CD86/CD28 interactions, contributes to the cytokine storm syndrome and subsequent tissue damage characteristic of severe COVID-19, particularly affecting pulmonary and vascular systems58. The convergence of CD86-mediated inflammatory pathways in both PCOS and COVID-19 suggests synergistic effects in individuals affected by both conditions. Exploration of CD86-targeted therapeutic strategies offers novel avenues to mitigate inflammation-driven complications in these conditions.ICAM-1, a pivotal cell surface glycoprotein central to immune responses and leukocyte adhesion59.ICAM-1, expressed on endothelial cells and leukocytes, facilitates immune cell adhesion and transmigration across endothelial barriers, thereby exacerbating localized inflammation and insulin resistance. Elevated ICAM-1 levels have been observed in PCOS patients, correlating with markers of inflammation and insulin resistance, suggesting a contributory role in the pathophysiology of metabolic and reproductive dysfunctions associated with PCOS48. Severe COVID-19 cases frequently exhibit endothelial activation and dysfunction, leading to enhanced vascular permeability and immune cell infiltration in vital organs. Upregulated ICAM-1 expression promotes leukocyte recruitment and adherence to endothelial cells, contributing to the cytokine storm syndrome and tissue damage characteristic of severe disease60. Higher ICAM-1 levels correlate with disease severity and adverse clinical outcomes in COVID-19 patients, highlighting its significance as a biomarker and potential therapeutic target61. The convergence of inflammatory pathways involving ICAM-1 in both PCOS and COVID-19 suggests a synergistic impact in individuals affected by both conditions. Women with PCOS contracting COVID-19 may experience heightened inflammatory responses and endothelial dysfunction, potentially exacerbating metabolic and cardiovascular complications linked to PCOS; nonetheless, how ICAM1 affects PCOS and SARS-Cov-2 needs further exploration.Thrombomodulin (THBD) is a pivotal glycoprotein renowned for its multifaceted roles in coagulation regulation and endothelial function62. THBD, primarily expressed on endothelial cells, plays a crucial role in modulating coagulation dynamics by converting thrombin to its anticoagulant form. It possesses anti-inflammatory properties through interactions with protein C63. SARS-CoV-2 infection triggers systemic inflammation, endothelial cell activation, and microvascular thrombosis, contributing significantly to disease severity64. THBD’s anticoagulant properties are pivotal in maintaining vascular integrity by inhibiting thrombin-mediated coagulation and attenuating endothelial activation65. However, in severe COVID-19 cases, endothelial cell shedding of THBD compromises its protective functions, exacerbating coagulopathy and inflammatory responses66. The dual functionality of THBD in regulating coagulation and inflammation underscores its potential impact on disease outcomes in both PCOS and COVID-19. Thus, comprehending the intricate involvement of THBD in these conditions is crucial for developing targeted therapeutic strategies aimed at mitigating vascular and inflammatory complications.MMP9 plays a pivotal role in extracellular matrix remodeling and inflammation, implicating its involvement in PCOS and COVID-19 pathophysiology67. Elevated MMP9 levels correlate with disrupted ovarian follicular development, impaired ovulation, and insulin signaling abnormalities observed in PCOS patients68. This is consistent with the results obtained in this study. These mechanisms underscore MMP9’s integral role in metabolic dysfunction and reproductive disturbances associated with the syndrome. Conversely, in COVID-19, MMP9’s activity exacerbates inflammatory responses critical to disease severity and outcomes69. Particularly in severe cases marked by cytokine storms and acute respiratory distress syndrome, MMP9 promotes immune cell infiltration and endothelial barrier disruption, contributing to lung injury and systemic inflammation70. Elevated MMP9 expression correlates with increased pulmonary fibrosis and adverse clinical outcomes in COVID-19 patients, highlighting its potential as both a prognostic biomarker and therapeutic target71. Understanding MMP9’s precise mechanisms in disease progression is crucial for developing tailored therapeutic strategies to alleviate inflammatory and metabolic dysfunctions associated with these complex conditions.ITGB2, a transmembrane glycoprotein pivotal for leukocyte adhesion and migration, facilitates immune cell recruitment and amplifies local inflammatory responses72. There are fewer studies on ITGB2 in PCOS, and we found that ITGB2 was significantly upregulated in PCOS patients and mouse models. We hypothesize that dysregulated ITGB2 expression correlates with intensified leukocyte infiltration and heightened inflammation, contributing to ovarian dysfunction and metabolic disturbances observed in PCOS patients. Similarly, in COVID-19, ITGB2-mediated leukocyte adhesion is crucial for orchestrating immune responses pivotal in disease progression73. ITGB2 promotes inflammatory cell recruitment to infection sites, exacerbating cytokine release and systemic inflammation. Elevated ITGB2 levels are associated with severe COVID-19 manifestations such as cytokine storms and acute respiratory distress syndrome, highlighting its role in modulating immune-mediated lung injury and vascular dysfunction74. Ongoing research into ITGB2’s molecular mechanisms and therapeutic implications is crucial for advancing precision medicine approaches aimed at mitigating inflammatory and metabolic dysfunctions associated with these complex conditions.This study also revealed the interaction of hub genes with ovary-specific genes. GO and KEGG Pathway analyses showed significant enrichment in inflammatory pathways, ovarian follicle development, and insulin signaling pathways. According to our findings in the PPI network, TLR2 interacted with MYD88, TLR1, IRF3, and other key players in the inflammatory response signaling pathway75,76. S100A9 could potentially interact with S100A8, and its complex was believed to facilitate cyst migration in PCOS development53. S100A9 could increase the production of inflammatory cytokines and disturb the steroidogenesis of PCOS77. It has been reported that S100A8 and S100A9 have diagnostic biomarker values and can be used to identify COVID-19 patients admitted to intensive care units78. Hence, S100A8 and S100A9 appeared to have important roles in causing COVID-19, as well as immune responses.In addition, we also found that EGFR proteins had direct or indirect interactions with S100A9, TLR2, ITGB, and ICAM1. As a critical factor in cell growth, differentiation, implantation, and decidualization, EGFR was vital for reproduction79. It is believed that the EGFR was responsible for facilitating proliferation and inhibiting apoptosis of granulosa cells by activating the MAPK/ERK signaling pathway and inducing transcription factor AP1 expression80. According to other studies, EGFR was expressed by cells of the lungs after SARS-CoV-2 infection. An elevated level of EGFR expression can further exacerbate pulmonary disease and cause fibrosis. Nimotuzumab can block the EGFR, which could be a novel treatment strategy for COVID-1981.We have identified micro-RNA species has-miR-21-5p, has-miR-335-5p, has-miR-146a-5p, and has-miR-143-5p shared by the hub genes. These micro-RNAs have been linked to the development of PCOS82,83,84. Among them, has-miR-335-5p and has-miR-146a-5p were demonstrated to be involved in the DEGs-miRNA network regulation in COVID-1985. In particular, our previous study displayed that miR-335-5p may function as a mediator in the etiopathogenesis of PCOS and has the potential as both a novel diagnostic biomarker and therapeutic target for PCOS19. Establishing a hub gene-miRNA network might provide new insights into the pathogenesis of PCOS and COVID-19.We also identified TFs closely associated with the hub genes. For instance, we identified STAT3, which participated in both TLR2 and S100A9 transcription. STAT3 has been shown to regulate the expression of TLR2 and S100A9. Given the roles of TLR2 and SA100A9 discussed above, we speculated that STAT3 might have the same function in PCOS and COVID-1986. Additionally, our previous study found that STAT3 could act directly on the miR-27a-3p promoter to induce granulosa cell apoptosis during the development of PCOS34.The drugs and chemical compounds found in our analysis include resveratrol, lipopolysaccharides, methotrexate, nickel, tretinoin, Captopril, and Glucosamine. For instance, tretinoin has been stipulated to regulate steroid biosynthesis in human ovarian theca cells87. In addition, resveratrol was used to regulate inflammation and oxidative stress of granulosa cells in PCOS via targeting TLR2, which was consistent with our above finding of TLR2 as a hub gene88.
