Search Results (66)

Epicardial mesothelial cells (EMCs), which form the epicardium, play a crucial role in cardiac homeostasis and repair. Upon damage, EMCs reactivate embryonic development programs, contributing to wound healing, progenitor cell amplification, and regulation of lymphangiogenesis, angiogenesis, and fibrosis. However, the mechanisms governing EMC activation and subsequent regulation remain poorly understood. We hypothesized that hepatocyte growth factor (HGF), a pleiotropic regulator of various cellular functions, could modulate EMC activity. To verify this hypothesis, we developed HGF-overexpressing mesenchymal stromal cell sheets (HGF-MSC CSs) and evaluated their effects on EMCs in vitro and in vivo. This study has revealed, for the first time, that EMCs express the c-Met (HGF receptor) on their surface and that both recombinant HGF and HGF-MSC CSs secretome cause c-Met phosphorylation, triggering downstream intracellular signaling. Our findings demonstrate that the HGF-MSC CSs secretome promotes cell survival under hypoxic conditions by modulating the level of autophagy. At the same time, HGF-MSC CSs stimulate EMC proliferation, promoting their amplification in the damage zone. These data demonstrate that HGF-MSC CSs can be considered a promising regulator of epicardial cell activity involved in heart repair after ischemic damage. Full article

Malignant pleural effusion (MPE) can lead to pleural organization with loculation and impaired drainage. This condition is becoming increasingly more common due to advancements in cancer therapy and extended patient survival. Factors such as repeated thoracentesis through an indwelling pleural catheter (IPC), intrapleural bleeding, and tumor progression contribute to MPE organization. Loculated MPE causes breathlessness and reduced quality of life, and current therapies, including intrapleural fibrinolytic or enzymatic therapy (IPFT/IET), have limitations in efficacy and safety. Identifying new therapeutic targets is crucial for improving treatment outcomes. Research is needed to understand the role of profibrogenic factors in pleural neoplasia, their regulation, and their impact on different stages of pleural organization. The development of a rabbit model of organizing MPE could provide insights into underlying mechanisms and novel interventions. Comparative studies of pleural tissues and effusions from MPE patients and other forms of pleural organization may reveal valuable information. Cellular and molecular profiling, assessment of biomarkers, and personalized IPFT dosing are potential areas of investigation. Suppression of PAI-1 activity and the role of hyaluronic acid in malignant mesothelioma are also important research directions. Understanding the profibrogenic capacity of pleural mesothelial cells undergoing mesenchymal transition (MesoMT) and identifying key contributors and effectors involved in this process are essential for developing effective treatments for loculated MPE. Full article

Background/Objectives: Cannabigerol (CBG) is a non-psychoactive phytocannabinoid with significant therapeutic potential, showing emerging applications in drug delivery. This study aimed to develop and evaluate CBG-conjugated nanoparticles (NPs) incorporating tubulin-targeting drugs to enhance anticancer activity. Methods: CBG was conjugated with N-desacetylthiocolchicine, paclitaxel, and camptothecin using sebacic acid and 4,4′-dithiodibutyric acid as linkers, and nanoparticles were obtained. The NPs were characterized by their stability and size (hydrodynamic diameters < 90 nm). Their antiproliferative activity was assessed in three human tumor cell lines and non-tumorigenic cells. Their cellular uptake and mechanisms of action were investigated via confocal microscopy and cell cycle analysis. Results: The chemical composition of the linkers significantly influenced the antiproliferative effect, with the NPs containing 4,4′-dithiodibutyric acid demonstrating higher activity. Notably, NP3b, formulated with this linker, exhibited up to an 80-fold increase in antiproliferative potency compared to its sebacic acid counterpart (NP3a). In mesothelioma cells (MSTO-211H), NP3b displayed significantly higher cytotoxicity than in non-tumorigenic mesothelial cells (MeT-5A), indicating selectivity for cancer cells. Further analysis in glioblastoma cells confirmed that the NPs retained the microtubule-disrupting effects of their parent drugs. Conclusions: These findings highlight the potential of CBG-based NPs as versatile nanomedicine platforms for targeted cancer therapy. This study underscores the importance of linker chemistry in modulating therapeutic efficacy and supports the development of multifunctional drug delivery systems. Full article

In adults, expressed in renal cancer (ERC)/mesothelin is exclusively expressed in the mesothelial cells lining the pleural, pericardial, and peritoneal cavities, yet its function under physiological conditions is unknown. To explore this, we studied ERC expression in wild-type (WT) mice at different developmental stages by immunohistochemistry and analyzed the ultrastructure of the mesothelium in WT and Erc-knockout (KO) mice via electron microscopy. Additionally, cardiopulmonary function in adult WT and Erc-KO mice was assessed using echocardiography and the forced oscillation technique (FOT). During embryonic development in WT mice, ERC expression was detected in the epicardium as early as embryonic day (E)12.5 but was absent in the pleura until E18.5. The timing of expression appeared to coincide with the active maturation of these organs, which implied a potential role in cardiopulmonary development. Electron microscopy revealed that microvilli on the mesothelium of Erc-KO mice were immature compared to those of WT mice. Based on these findings, we hypothesized that ERC might contribute to cardiopulmonary function; however, echocardiography and FOT did not reveal any functional differences between WT and Erc-KO mice. This suggests that ERC has limited functional relevance under physiological conditions. Full article

Background/Objectives: Long-term peritoneal dialysis (PD) often results in peritoneal damage and fibrosis, impairing peritoneal membrane function and leading to ultrafiltration failure. This study aimed to explore the therapeutic potential of nintedanib and pirfenidone in preventing and treating PD-associated peritoneal fibrosis using experimental models. Methods: An animal model of peritoneal fibrosis and cultured mesothelial cells were utilized to evaluate the effects of nintedanib and pirfenidone. Histological analysis, molecular techniques, and RNA sequencing were employed to assess the fibrosis, inflammation, and gene expression. The key outcomes included changes in the peritoneal structure, inflammatory markers, and transcriptional regulation. Results: Induced peritoneal fibrosis resulted in significant structural and histological changes. Treatment with nintedanib and pirfenidone effectively prevented peritoneal thickening and reduced excessive fibrosis deposition. Both agents ameliorated the inflammatory responses by lowering inflammatory marker expression, inhibiting cytokine activity, and decreasing macrophage infiltration. Molecular analyses revealed the suppression of inflammation-related transcription regulators and cytokine receptors. RNA sequencing identified glucose-induced gene expression changes and demonstrated significant modulation by the treatments. In animal studies with established fibrosis, these agents reduced peritoneal inflammation and slowed fibrosis progression. Conclusions: This study demonstrates that intraperitoneal administration of nintedanib and pirfenidone shows promise as an anti-fibrosis therapy for preventing and treating peritoneal fibrosis associated with PD. These findings highlight the potential of targeted interventions to improve the long-term outcomes for PD patients. Full article

During long-term peritoneal dialysis, peritoneal fibrosis (PF) often happens and results in ultrafiltration failure, which directly leads to the termination of dialysis. The accumulation of extracellular matrix produced from an increasing number of myofibroblasts was a hallmark characteristic of PF. To date, glucose degradation products (GDPs, i.e., methylglyoxal (MGO)) that appeared during the heating and storage of the dialysate are considered to be key components to initiating PF, but how GDPs lead to the activation of myofibroblast in fibrotic peritoneum has not yet been fully elucidated. In this study, mesothelial cell line (MeT-5A) and fibroblast cell line (MRC-5) were used to investigate the transcriptomic and proteomic changes to unveil the underlying mechanism of MGO-induced PF. Our transcriptomic data from the MGO-stimulated mesothelial cells showed upregulation of genes involved in pro-inflammatory, apoptotic, and fibrotic pathways. While no phenotypic changes were noted on fibroblasts after direct MGO, supernatant from MGO-stimulated mesothelial cells promoted fibroblasts to change into proto-myofibroblasts, activated fibroblasts in the first stage toward myofibroblasts. In conclusion, this study showed that MGO-stimulated mesothelial cells promoted fibroblast-to-proto-myofibroblast transition; however, additional involvement of other factors or cells (e.g., macrophages) may be needed to complete the transformation into myofibroblasts. Full article

Late-stage epithelial ovarian cancer (EOC) involves the widespread dissemination of malignant disease throughout the peritoneal cavity, often accompanied by ascites. EOC metastasis relies on the formation of multicellular aggregates, called spheroids. Given that Liver Kinase B1 (LKB1) is required for EOC spheroid viability and LKB1 loss in EOC cells decreases tumor burden in mice, we investigated whether the LKB1 complex controls the invasive properties of human EOC spheroids. LKB1 signalling was antagonized through the CRISPR/Cas9 genetic knockout of LKB1 and/or the RNAi-dependent targeting of STE20-related kinase adaptor protein (STRAD, an LKB1 activator). EOC spheroids expressing nuclear GFP (green) or mKate2 (red) constructs were embedded in Matrigel for real-time live-cell invasion monitoring. Migration and invasion were also assessed in spheroid culture using Transwell chambers, spheroid reattachment, and mesothelial clearance assays. The loss of LKB1 and STRAD signalling decreased cell invasion through Matrigel and Transwell membranes, as well as mesothelial cell clearance. In the absence of LKB1, zymographic assays identified a loss of matrix metalloproteinase (MMP) activity, whereas spheroid reattachment assays found that coating plates with fibronectin restored their invasive potential. A three-dimensional EOC organoid model demonstrated that organoid area was greatly reduced by LKB1 loss. Overall, our data indicated that LKB1 and STRAD facilitated EOC metastasis by promoting MMP activity and fibronectin expression. Given that LKB1 and STRAD are crucial for EOC metastasis, targeting LKB1 and/or STRAD could disrupt the dissemination of EOC, making inhibitors of the LKB1 pathway an alternative therapeutic strategy for EOC patients. Full article

The characteristic feature of chronic peritoneal damage in peritoneal dialysis (PD) is a decline in ultrafiltration capacity associated with pathological fibrosis and angiogenesis. The pathogenesis of peritoneal fibrosis is attributed to bioincompatible factors of PD fluid and peritonitis. Uremia is associated with peritoneal membrane inflammation that affects fibrosis, neoangiogenesis, and baseline peritoneal membrane function. Net ultrafiltration volume is affected by capillary surface area, vasculopathy, peritoneal fibrosis, and lymphangiogenesis. Many inflammatory cytokines induce fibrogenic growth factors, with crosstalk between macrophages and fibroblasts. Transforming growth factor (TGF)-β and vascular endothelial growth factor (VEGF)-A are the key mediators of fibrosis and angiogenesis, respectively. Bioincompatible factors of PD fluid upregulate TGF-β expression by mesothelial cells that contributes to the development of fibrosis. Angiogenesis and lymphangiogenesis can progress during fibrosis via TGF-β–VEGF-A/C pathways. Complement activation occurs in fungal peritonitis and progresses insidiously during PD. Analyses of the human peritoneal membrane have clarified the mechanisms by which encapsulating peritoneal sclerosis develops. Different effects of dialysates on the peritoneal membrane were also recognized, particularly in terms of vascular damage. Understanding the pathophysiologies of the peritoneal membrane will lead to preservation of peritoneal membrane function and improvements in technical survival, mortality, and quality of life for PD patients. Full article

Carcinoma-associated fibroblasts (CAFs) are highly accumulated in the tumor-surrounding stroma of primary epithelial ovarian cancer (OC). CAFs exert important functions for the vascularization, growth, and progression of OC cells. However, the origin of CAFs in primary OC had not yet been studied, and they were assumed to arise from the activation of resident fibroblasts. Here, we compared CAFs in the ovary to CAFs found in peritoneal metastases from patients with advanced OC. Our findings show that CAFs from primary tumors and peritoneal metastases share the expression of mesothelial markers. Therefore, similar to peritoneal carcinomatosis, CAFs in primary ovarian carcinomas may originate from mesothelial cells via a mesothelial-to-mesenchymal transition. The detection of mesothelial-derived CAFs in tumors confined to the ovary and identification of biomarkers could be the key to the early detection of OC and peritoneal spread. Full article

There is paucity of studies that focus on the composition of pericardial fluid under resting conditions. The purpose of this study is to determine the levels of inflammatory mediators in pericardial fluid and their correlation with plasma levels in patients undergoing elective cardiac surgery. We conducted a prospective cohort study on candidates for elective aortic valve replacement surgery. Pericardial fluid and peripheral venous blood samples were collected after opening the pericardium. Levels of interleukin 1α (IL-1α); interleukin 1β (IL-1β); interleukin 2 (IL-2) interleukin 4 (IL-4); interleukin 6 (IL-6); interleukin 8 (IL8); interleukin 10 (IL10); tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1) epidermal growth factor (EGF), soluble E-selectin, L-selectin, P-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were determined in both pericardial fluid and serum samples. A total of 45 patients with a mean age of 74 years were included of which 66% were males. Serum levels of all study mediators were within normal limits. Serum and pericardial levels of IL-1 α, IL-1 β, IL-2, IL-4, and IL-10 were similar. Levels of VEGF, EGF, VCAM-2, ICAM 1, E-selectin, P-selectin, and L-selectin were significantly lower in pericardial fluid than in serum. However, levels of IL-6, IL-8, TNF-α, IFN-γ, MCP-1, and MCP-1 were significantly higher in the pericardial fluid than in serum. Under normal conditions, the pattern of distribution of different inflammatory mediators in the pericardial fluid does not reflect serum levels. This may either reflect the condition of the underlying myocardium and epicardial fat or the activity of the mesothelial and mononuclear cells present in pericardial fluid. Full article

Peritoneal dialysis (PD) is a current replacement therapy for end-stage kidney diseases (ESKDs). However, long-term exposure to PD fluids may lead to damage of the peritoneal membrane (PM) through mechanisms involving the activation of the inflammatory response and mesothelial-to-mesenchymal transition (MMT), leading to filtration failure. Peritoneal damage depends on a complex interaction among external stimuli, intrinsic properties of the PM, and subsequent activities of the local innate–adaptive immune system. Epigenetic drugs targeting bromodomain and extra-terminal domain (BET) proteins have shown beneficial effects on different experimental preclinical diseases, mainly by inhibiting proliferative and inflammatory responses. However the effect of BET inhibition on peritoneal damage has not been studied. To this aim, we have evaluated the effects of treatment with the BET inhibitor JQ1 in a mouse model of peritoneal damage induced by chlorhexidine gluconate (CHX). We found that JQ1 ameliorated the CHX-induced PM thickness and inflammatory cell infiltration. Moreover, JQ1 decreased gene overexpression of proinflammatory and profibrotic markers, together with an inhibition of the nuclear factor-κB (NF-κB) pathway. Additionally, JQ1 blocked the activation of nuclear factor erythroid 2-related factor 2 (NRF2) and restored changes in the mRNA expression levels of NADPH oxidases (NOX1 and NOX4) and NRF2/target antioxidant response genes. To corroborate the in vivo findings, we evaluated the effects of the BET inhibitor JQ1 on PD patients’ effluent-derived primary mesothelial cells and on the MeT-5A cell line. JQ1 inhibited tumor necrosis factor-α (TNF-α)-induced proinflammatory gene upregulation and restored MMT phenotype changes, together with the downmodulation of oxidative stress. Taken together, these results suggest that BET inhibitors may be a potential therapeutic option to ameliorate peritoneal damage. Full article

In our preliminary experiment, peritoneal sclerosis likely induced by peritoneal dialysis was unexpectedly observed in the livers of rats given bleomycin and lansoprazole. We examined whether this peritoneal thickening around the liver was time-dependently induced by administration of both drugs. Male Wistar rats were injected with bleomycin and/or lansoprazole for 2 or 4 weeks. The 3YB-1 cell line derived from rat fibroblasts was treated by bleomycin and/or lansoprazole for 24 h. The administration of both drugs together, but not individually, thickened the peritoneal tissue around the liver. There was accumulation of collagen fibers, macrophages, and eosinophils under mesothelial cells. Expressions of Col1a1, Mcp1 and Mcp3 genes were increased in the peritoneal tissue around the liver and in 3YB-1 cells by the administration of both drugs together, and Opn genes had increased expressions in this tissue and 3YB-1 cells. Mesothelial cells indicated immunoreactivity against both cytokeratin, a mesothelial cell marker, and αSMA, a fibroblast marker, around the livers of rats given both drugs. Administration of both drugs induced the migration of macrophages and eosinophils and induced fibrosis associated with the possible activation of fibroblasts and the possible promotion of the mesothelial–mesenchymal transition. This might become a novel model of peritoneal sclerosis for peritoneal dialysis. Full article

Estrogen receptor-positive (ER+) invasive lobular breast cancer (ILC) comprises about ~15% of breast cancer. ILC’s unique genotypic (loss of wild type E-cadherin expression) and phenotypic (small individual round cancer cells that grow in discontinuous nests) are thought to contribute to a distinctive pattern of metastases to serosal membranes. Unlike invasive ductal carcinoma (IDC), ILC metastases often intercalate into the mesothelial layer of the peritoneum and other serosal surfaces. While ER activity is a known driver of ILC proliferation, very little is known about how additional nuclear receptors contribute to ILC’s distinctive biology. In ER+ IDC, we showed previously that glucocorticoid receptor (GR) activity inhibits pro-proliferative gene expression and cell proliferation. Here we examined ER+ ILC models and found that GR activation similarly reduces S-phase entry gene expression and ILC proliferation. While slowing tumor growth rate, our data also suggest that GR activation results in an enhanced metastatic phenotype through increasing integrin-encoding gene expression, extracellular matrix protein adhesion, and mesothelial cell clearance. Moreover, in an intraductal mouse mammary gland model of ILC, we found that GR expression is associated with increased bone metastases despite slowed primary mammary tumor growth. Taken together, our findings suggest GR-mediated gene expression may contribute to the unusual characteristics of ILC biology. Full article

The sensitivity of pleural fluid (PF) analyses for the diagnosis of malignant pleural effusions (MPEs) is low to moderate. Knowledge about the pathobiology and molecular characteristics of this condition is limited. In this study, the crosstalk between stromal cells and tumor cells was investigated in vitro in order to reveal factors that are present in PF which can mediate MPE formation and aid in discriminating between benign and malignant etiologies. Eighteen PF samples, in different proportions, were exposed in vitro to mesothelial MeT-5A cells to determine the biological effects on these cells. Treatment of normal mesothelial MeT-5A cells with malignant PF increased cell viability, proliferation, and migration, and activated different survival-related signaling pathways. We identified differentially expressed miRNAs in PF samples that could be responsible for these changes. Consistently, bioinformatics analysis revealed an enrichment of the discovered miRNAs in migration-related processes. Notably, the abundance of three miRNAs (miR-141-3p, miR-203a-3, and miR-200c-3p) correctly classified MPEs with false-negative cytological examination results, indicating the potential of these molecules for improving diagnosis. Malignant PF produces phenotypic and functional changes in normal mesothelial cells. These changes are partly mediated by certain miRNAs, which, in turn, could serve to differentiate malignant from benign effusions. Full article

Pleural mesothelioma (PM) is an aggressive malignancy that develops in a unique tumor microenvironment (TME). However, cell models for studying the TME in PM are still limited. Here, we have generated and characterized novel human telomerase reverse transcriptase (hTERT)-transduced mesothelial cell and mesothelioma-associated fibroblast (Meso-CAF) models and investigated their impact on PM cell growth. Pleural mesothelial cells and Meso-CAFs were isolated from tissue of pneumothorax and PM patients, respectively. Stable expression of hTERT was induced by retroviral transduction. Primary and hTERT-transduced cells were compared with respect to doubling times, hTERT expression and activity levels, telomere lengths, proteomes, and the impact of conditioned media (CM) on PM cell growth. All transduced derivatives exhibited elevated hTERT expression and activity, and increased mean telomere lengths. Cell morphology remained unchanged, and the proteomes were similar to the corresponding primary cells. Of note, the CM of primary and hTERT-transduced Meso-CAFs stimulated PM cell growth to the same extent, while CM derived from mesothelial cells had no stimulating effect, irrespective of hTERT expression. In conclusion, all new hTERT-transduced cell models closely resemble their primary counterparts and, hence, represent valuable tools to investigate cellular interactions within the TME of PM. Full article