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Endometriosis (EM) is defined as the engraftment and proliferation of functional endometrial-like tissue outside the uterine cavity, leading to a chronic inflammatory condition. While the precise etiology of EM remains elusive, recent studies have highlighted the crucial involvement of a dysregulated immune system. The complement system is one of the predominantly altered immune pathways in EM. Owing to its involvement in the process of angiogenesis, here, we have examined the possible role of the first recognition molecule of the complement classical pathway, C1q. C1q plays seminal roles in several physiological and pathological processes independent of complement activation, including tumor growth, placentation, wound healing, and angiogenesis. Gene expression analysis using the publicly available data revealed that C1q is expressed at higher levels in EM lesions compared to their healthy counterparts. Immunohistochemical analysis confirmed the presence of C1q protein, being localized around the blood vessels in the EM lesions. CD68+ macrophages are the likely producer of C1q in the EM lesions since cultured EM cells did not produce C1q in vitro. To explore the underlying reasons for increased C1q expression in EM, we focused on its established pro-angiogenic role. Employing various angiogenesis assays on primary endothelial endometriotic cells, such as migration, proliferation, and tube formation assays, we observed a robust proangiogenic effect induced by C1q on endothelial cells in the context of EM. C1q promoted angiogenesis in endothelial cells isolated from EM lesions (as well as healthy ovary that is also rich in C1q). Interestingly, endothelial cells from EM lesions seem to overexpress the receptor for the globular heads of C1q (gC1qR), a putative C1q receptor. Experiments with siRNA to silence gC1qR resulted in diminished capacity of C1q to perform its angiogenic functions, suggesting that C1q is likely to engage gC1qR in the pathophysiology of EM. gC1qR can be a potential therapeutic target in EM patients that will disrupt C1q-mediated proangiogenic activities in EM. [ABSTRACT FROM AUTHOR]

The complement system (C) is a crucial component of the innate immune system. An increasing body of research has progressively shed light on the pivotal role of C in immunological tolerance at the feto-maternal interface. Excessive C activation or impaired C regulation may determine the onset of pregnancy-related pathological conditions, including pre-eclampsia (PE). Thus, several studies have investigated the presence of C components or split products in blood matrixes (i.e., plasma, serum), urine, and amniotic fluid in PE. In the current study, we systematically reviewed the currently available scientific literature reporting measurements of C components as circulating biomarkers in PE, based on a literature search using Pubmed, Scopus, and Embase databases. A total of 41 out of 456 studies were selected after full-text analysis. Fourteen studies (34.1%) were identified as measuring the blood concentrations of the classical pathway, 5 (12.1%) for the lectin pathway, 28 (68.3%) for the alternative pathway, 17 (41.5%) for the terminal pathway components, and 16 (39%) for C regulators. Retrieved results consistently reported C4, C3, and factor H reduction, and increased circulating levels of C4d, Bb, factor D, C3a, C5a, and C5b-9 in PE compared to normal pregnancies, depicting an overall scenario of excessive C activation and aberrant C regulation. With evidence of C activation and dysregulation, C-targeted therapy is an intriguing perspective in PE management. Moreover, we also discussed emerging pitfalls in C analysis, mainly due to a lack of experimental uniformity and biased cohort selection among different studies and laboratories, aiming to raise a more comprehensive awareness for future standardization. [ABSTRACT FROM AUTHOR]

Background: The identification of novel therapeutic strategies for ovarian cancer (OC), the most lethal gynecological neoplasm, is of utmost urgency. Here, we have tested the effectiveness of the compound 2c (4-hydroxy-2,6-bis(4-nitrobenzylidene)cyclohexanone 2). 2c interferes with the cysteine-dependent deubiquitinating enzyme (DUB) UCHL5, thus affecting the ubiquitin-proteasome-dependent degradation of proteins. Methods: 2c phenotypic/molecular effects were studied in two OC 2D/3D culture models and in a mouse xenograft model. Furthermore, we propose an in silico model of 2c interaction with DUB-UCHL5. Finally, we have tested the effect of 2c conjugated to several linkers to generate 2c/derivatives usable for improved drug delivery. Results: 2c effectively impairs the OC cell line and primary tumor cell viability in both 2D and 3D conditions. The effectiveness is confirmed in a xenograft mouse model of OC. We show that 2c impairs proteasome activity and triggers apoptosis, most likely by interacting with DUB-UCHL5. We also propose a mechanism for the interaction with DUB-UCHL5 via an in silico evaluation of the enzyme-inhibitor complex. 2c also reduces cell growth by down-regulating the level of the transcription factor E2F1. Eventually, 2c activity is often retained after the conjugation with linkers. Conclusion: Our data strongly support the potential therapeutic value of 2c/derivatives in OC. [ABSTRACT FROM AUTHOR]

Complement component C1q can act as a pro-tumorigenic factor in the tumor microenvironment (TME). The TME in malignant pleural mesothelioma (MPM) is rich in C1q and hyaluronic acid (HA), whose interaction enhances adhesion, migration and proliferation of malignant cells. HA-bound C1q is also capable of modulating HA synthesis. Thus, we investigated whether HA-C1q interaction would affect HA degradation, analyzing the main degradation enzymes, hyaluronidase (HYAL)1 and HYAL2, and a C1q receptor candidate. We first proceeded with the characterization of HYALs in MPM cells, especially HYAL2, since bioinformatics survival analysis revealed that higher HYAL2 mRNA levels have an unfavorable prognostic index in MPM patients. Interestingly, Real-Time quantitative PCR, flow cytometry and Western blot highlighted an upregulation of HYAL2 after seeding of primary MPM cells onto HA-bound C1q. In an attempt to unveil the receptors potentially involved in HA-C1q signaling, a striking colocalization between HYAL2 and globular C1q receptor/HABP1/p32 (gC1qR) was found by immunofluorescence, surface biotinylation and proximity ligation assays. RNA interference experiments revealed a potentially regulatory function exerted by gC1qR on HYAL2 expression, since C1QBP (gene for gC1qR) silencing unexpectedly caused HYAL2 downregulation. In addition, the functional blockage of gC1qR by a specific antibody hindered HA-C1q signaling and prevented HYAL2 upregulation. Thus, C1q-HA interplay is responsible for enhanced HYAL2 expression, suggesting an increased rate of HA catabolism and the release of pro-inflammatory and pro-tumorigenic HA fragments in the MPM TME. Our data support the notion of an overall tumor-promoting property of C1q. Moreover, the overlapping localization and physical interaction between HYAL2 and gC1qR suggests a potential regulatory effect of gC1qR within a putative HA-C1q macromolecular complex. [ABSTRACT FROM AUTHOR]