Prostaglandin E2 suppresses KCNH1 gene expression and inhibits the proliferation of CaSki cervical cells through its four prostanoid PTGER subtypes.

The main risk factor for cervical cancer is the persistent infection of high-risk HPV subtypes, notably HPV16. Another contributing factor is proinflammatory prostaglandin E2 (PGE2), a lipid abundantly found in seminal fluid. PGE2, along with its receptors (PTGER1-4), contributes to cancer development; however, its specific role in the proliferation of cervical cancer models with high HPV16 copy numbers remains unclear. In this study, we investigated the effects of PGE2 on the proliferation of CaSki cells, a cell line with a high HPV16 viral load. Surprisingly, PGE2 inhibited CaSki cell proliferation, while it increased the proliferation of SiHa, HeLa, and C-33 A cervical cancer cells. The effect of PGE2 on CaSki cell proliferation was specific, as estradiol increased cell growth. Furthermore, PGE2 suppressed expression and promoter activity of the cervical tumoral marker KCNH1. To discern the specific role of each receptor in cell proliferation, we generated stable CaSki cell lines overexpressing each receptor alongside control cells with an empty vector. Notably, PGE2 significantly inhibited cell proliferation in all stable transfected CaSki cells, suppressing oncogenic KCNH1 expression and its promoter activity. In conclusion, our findings indicate that PGE2 inhibits the proliferation of CaSki cervical cancer cells with a high HPV16 load, at least in part, by suppressing the expression of the oncogenic KCNH1 gene.

NitraTh epitope-based neoantigen vaccines for effective tumor immunotherapy.

Neoantigen vaccines represent an emerging and promising strategy in the field of tumor immunotherapy. Despite their potential, designing an effective neoantigen vaccine remains a challenge due to the current limitations in predicting CD4+ T cell epitopes with high accuracy. Here, we introduce a novel approach to neoantigen vaccine design that does not rely on computational prediction of CD4+ T cell epitopes. Utilizing nitrated helper T cell epitope containing p-nitrophenylalanine, termed "NitraTh epitope," we have successfully engineered a series of tumor neoantigen vaccines capable of eliciting robust neoantigen-specific immune responses. With the help of NitraTh epitope, even mutations with low predicted affinity for MHC class I molecules were successfully induced to elicit neoantigen-specific responses. In H22 cell allograft and patient-derived xenograft (PDX) liver cancer mouse models, the NitraTh epitope-based neoantigen vaccines significantly suppressed tumor progression. More strikingly, through single-cell sequencing we found that the NitraTh epitope-based neoantigen vaccines regulate macrophage reprogramming and modulate macrophages to decrease the levels of the immunosuppressive molecule prostaglandin E2 (PGE2), which in turn reshapes the tumor immunosuppressive microenvironment. In summary, NitraTh epitope-based neoantigen vaccines possess the dual effects of potently activating neoantigen-specific immunity and alleviating immunosuppression, potentially providing a new paradigm for the design of tumor neoantigen vaccines.

Aqueous Extracts of Rhus trilobata Inhibit the Lipopolysaccharide-Induced Inflammatory Response In Vitro and In Vivo.

Chronic noncommunicable diseases (NCDs) are responsible for approximately 74% of deaths globally. Medicinal plants have traditionally been used to treat NCDs, including diabetes, cancer, and rheumatic diseases, and are a source of anti-inflammatory compounds. This study aimed to evaluate the anti-inflammatory effects of Rhus trilobata (Rt) extracts and fractions in lipopolysaccharide (LPS)-induced inflammation models in vitro and in vivo. The aqueous extract (RtAE) and five fractions (F2 to F6) were obtained via C18 solid-phase separation and tested in murine LPS-induced J774.1 macrophages. Key inflammatory markers, such as IL-1ß, IL-6, TNF-α, and COX-2 gene expression were measured using RT-qPCR, and PGE2 production was assessed via HPLC-DAD. The in vivo effects were tested in an LPS-induced paw edema model in Wistar rats. Results showed that RtAE at 15 µg/mL significantly decreased IL-1ß and IL-6 gene expression in vitro. Fraction F6 further reduced IL-1ß, TNF-α, and IL-6 gene expression, COX-2 expression, and PGE2 production. In vivo, F6 significantly reduced LPS-induced paw edema, inflammatory infiltration, and IL-1ß and COX-2 protein expression. Chemical characterization of F6 by UPLC/MS-QTOF revealed at least eight compounds with anti-inflammatory activity. These findings support the anti-inflammatory potential of RtAE and F6, reinforcing the medicinal use of Rt.

Roles of Toll-like Receptor Signaling in Inflammatory Bone Resorption.

Toll-like receptors (TLRs) are pattern recognition receptors expressed in immune cells, including neutrophils, macrophages, and dendritic cells. Microbe-associated molecular patterns, including bacterial components, membranes, nucleic acids, and flagella are recognized by TLRs in inflammatory immune responses. Periodontal disease is an inflammatory disease known to cause local infections associated with gingival inflammation, subsequently leading to alveolar bone resorption. Prostaglandin E2 (PGE2) is a key mediator of TLR-induced inflammatory bone resorption. We previously reported that membrane-bound PGE synthase (mPGES-1)-deficient mice failed to induce bone resorption by lipopolysaccharide (LPS), a major pathogenic factor involved in periodontal bone resorption. Further experiments exploring specific pathogen-promoting osteoclast differentiation revealed that various TLR ligands induced osteoclast differentiation in a co-culture model. The ligands for TLR2/1, TLR2/6, TLR3, and TLR5, as well as TLR4, induce osteoclast differentiation associated with the production of PGE2 and the receptor activator of nuclear factor-kappa B ligand (RANKL), an inevitable inducer of osteoclast differentiation in osteoblasts. In vivo, local injection of TLR ligands, including TLR2/1, TLR2/6, and TLR3, resulted in severe alveolar bone resorption. This review summarizes the latest findings on TLR-mediated osteoclast differentiation and bone resorption in inflammatory diseases, such as periodontal diseases.

Pulmonary surfactant and prostaglandin E2 in airway smooth muscle relaxation of human and male guinea pigs.

Pulmonary surfactant serves as a barrier to respiratory epithelium but can also regulate airway smooth muscle (ASM) tone. Surfactant (SF) relaxes contracted ASM, similar to ß2-agonists, anticholinergics, nitric oxide, and prostanoids. The exact mechanism of surfactant relaxation and whether surfactant relaxes hyperresponsive ASM remains unknown. Based on previous research, relaxation requires an intact epithelium and prostanoid synthesis. We sought to examine the mechanisms by which surfactant causes ASM relaxation. Organ bath measurements of isometric tension of ASM of guinea pigs in response to exogenous surfactant revealed that surfactant reduces tension of healthy and hyperresponsive tracheal tissue. The relaxant effect of surfactant was reduced if prostanoid synthesis was inhibited and/or if prostaglandin E2-related EP2 receptors were antagonized. Atomic force microscopy revealed that human ASM cells stiffen during contraction and soften during relaxation. Surfactant softened ASM cells, similarly to the known bronchodilator prostaglandin E2 (PGE2) and the cell softening was abolished when EP4 receptors for PGE2 were antagonized. Elevated levels of PGE2 were found in cultures of normal human bronchial epithelial cells exposed to pulmonary surfactant. We conclude that prostaglandin E2 and its EP2 and EP4 receptors are likely involved in the relaxant effect of pulmonary surfactant in airways.

Inhibition of 15-prostaglandin dehydrogenase attenuates acetaminophen-induced liver injury via suppression of apoptosis in liver endothelial cells.

Hepatic microvascular disruption caused by injury to liver sinusoidal endothelial cells (LSECs) is an aggravating factor for drug-induced liver injury (DILI). It is suggested that prostaglandin E2 (PGE2) may be able to attenuate LSEC injury. However, it is also known that 15-keto PGE2, a metabolite of PGE2 produced by 15-prostaglandin dehydrogenase (15-PGDH) that is not a ligand of PGE2 receptors, suppresses inflammatory acute liver injury as a ligand of peroxisome proliferator-activated receptor γ. In this study, we aimed to understand whether 15-PGDH activity is essential for preventing DILI by suppressing hepatic microvascular disruption in a mouse model of acetaminophen (APAP)-induced liver injury. To inhibit 15-PGDH activity prior to APAP-induced LSEC injury, we administered the 15-PGDH inhibitor, SW033291, 1 h before and 3 h after APAP treatment. We observed that LSEC injury preceded hepatocellular injury in APAP administered mice. Hepatic endogenous PGE2 levels did not increase up till the initiation of LSEC injury but rather increased after hepatocellular injury. Moreover, hepatic 15-PGDH activity was downregulated in APAP-induced liver injury. The inhibition of 15-PGDH attenuated LSEC injury and subsequently hepatic injury by inhibiting apoptosis in APAP administered mice. Our in vitro studies also suggested that PGE2 inhibited APAP-induced apoptosis via the EP4/PI3K pathway in endothelial cells. Therefore, a decrease in 15-PGDH activity would be beneficial for preventing APAP-induced liver injury by attenuating LSEC injury.

Effect of curcumin on formalin-induced muscle pain in male rats: role of local cyclooxygenase system.

Investigating the mechanisms responsible for pain processing of natural and synthetic chemical compounds is necessary to optimize pain management. Curcumin (Cur), the active ingredient of turmeric, exhibits potent analgesic and anti-inflammatory properties by employing multiple mechanisms at the local peripheral, spinal and supra-spinal levels. This study was aimed to investigate the effect of oral administration of Cur on muscle pain induced by intramuscular (IM) injection of formalin. To explore the possible local mechanisms, a cyclooxygenase (COX) inhibitor, diclofenac (Dic) and a COX product, prostaglandin E2 (PGE2), were applied. The IM injection of formalin (25.00 µL, 2.50%) into the gastrocnemius muscle induced two distinct phases of hind leg flinching. A short-lasting (10 min) hind leg lifting was observed following IM injection of PGE2 (2 µg kg-1, 25.00 µL). Oral administration of Cur (25.00 and 100 mg kg-1) and IM injection of 40.00 µg kg-1 Dic attenuated formalin and PGE2 induced nociceptive behaviors. Contra-lateral IM injection of Dic did not change muscle pain induced by ipsilateral IM injection of formalin and PGE2. The second phase of formalin induced flinching as well as PGE2 evoked lifting were more suppressed when 40.00 µg kg-1 Dic and 100 mg kg-1 Cur were used together. Locomotor activity was not changed by the above-mentioned treatments. It was concluded that the reducing effect of muscle pain of Cur might be related to the local inhibition of COX.

Spinster homolog 2/S1P signaling ameliorates macrophage inflammatory response to bacterial infections by balancing PGE2 production.

BACKGROUND: Mitochondria play a crucial role in shaping the macrophage inflammatory response during bacterial infections. Spinster homolog 2 (Spns2), responsible for sphingosine-1-phosphate (S1P) secretion, acts as a key regulator of mitochondrial dynamics in macrophages. However, the link between Spns2/S1P signaling and mitochondrial functions remains unclear. METHODS: Peritoneal macrophages were isolated from both wild-type and Spns2 knockout rats, followed by non-targeted metabolomics and RNA sequencing analysis to identify the potential mediators through which Spns2/S1P signaling influences the mitochondrial functions in macrophages. Various agonists and antagonists were used to modulate the activation of Spns2/S1P signaling and its downstream pathways, with the underlying mechanisms elucidated through western blotting. Mitochondrial functions were assessed using flow cytometry and oxygen consumption assays, as well as morphological analysis. The impact on inflammatory response was validated through both in vitro and in vivo sepsis models, with the specific role of macrophage-expressed Spns2 in sepsis evaluated using Spns2flox/floxLyz2-Cre mice. Additionally, the regulation of mitochondrial functions by Spns2/S1P signaling was confirmed using THP-1 cells, a human monocyte-derived macrophage model. RESULTS: In this study, we unveil prostaglandin E2 (PGE2) as a pivotal mediator involved in Spns2/S1P-mitochondrial communication. Spns2/S1P signaling suppresses PGE2 production to support malate-aspartate shuttle activity. Conversely, excessive PGE2 resulting from Spns2 deficiency impairs mitochondrial respiration, leading to intracellular lactate accumulation and increased reactive oxygen species (ROS) generation through E-type prostanoid receptor 4 activation. The overactive lactate-ROS axis contributes to the early-phase hyperinflammation during infections. Prolonged exposure to elevated PGE2 due to Spns2 deficiency culminates in subsequent immunosuppression, underscoring the dual roles of PGE2 in inflammation throughout infections. The regulation of PGE2 production by Spns2/S1P signaling appears to depend on the coordinated activation of multiple S1P receptors rather than any single one. CONCLUSIONS: These findings emphasize PGE2 as a key effector of Spns2/S1P signaling on mitochondrial dynamics in macrophages, elucidating the mechanisms through which Spns2/S1P signaling balances both early hyperinflammation and subsequent immunosuppression during bacterial infections.

Progressively Diminished Prostaglandin E2 Signaling in Concordance with Increasing Fibrosis in Ectopic Endometrium.

The prostaglandin E2 (PGE2) signaling has traditionally been viewed to play a pivotal role in endometriosis, linking inflammation and hyperestrogenism. We have previously reported that asectopic endometrium becomes more fibrotic, the expression of both COX-2 and PGE2 receptors (EP2 and EP4) are reduced. This study further investigatedwhether the expression levels of genes involved in the biosynthesis and metabolism of PGE2in ectopic endometrium diminish in concordance with increasing lesional fibrosis. We performed immunohistochemistry analyses of COX-2, mPGES-1, mPGES-2, cPGES, 15-PGDH, EP2 and EP4 and Masson trichrome staining for ovarian endometrioma (OE), adenomyosis (AD), and deep endometriosis (DE) tissue samples and control endometrial tissue samples (CT). Gene and protein expression analyses were performed by real-time RT-PCR and Western blotting, respectively. We found that as the extent of lesional fibrosis increased, immunoexpression of COX-2, mPGES-1/2, cPGES, EP2 and EP4 in OE lesions was increased but no change in these genes/proteins in DE lesions as compared with CT. Immunoexpression of COX-2 was found to be reduced while that of 15-PGDH was found to be elevated in DE lesions. In AD lesions, only EP2 and COX-2 were overexpressed. Thus, our data indicate that when the extent of lesional fibrosis is high, the PGE2 signaling pathway is depressed, manifesting as reduced COX-2 expression and elevated expression of 15-PGDH. They underscore the fact that not all ectopic endometria are the same and equal, and highlight the importance of the extracellular matrix in shaping the lesional behavior and response to drug treatment.

Potential Human Health Benefits of Phaseolus vulgaris L. var Venanzio: Effects on Cancer Cell Growth and Inflammation.

It is widely recognized that foods, biodiversity, and human health are strongly interconnected, and many efforts have been made to understand the nutraceutical value of diet. In particular, diet can affect the progression of intestinal diseases, including inflammatory bowel disease (IBD) and intestinal cancer. In this context, we studied the anti-inflammatory and antioxidant activities of extracts obtained from a local endangered variety of Phaseolus vulgaris L. (Fagiola di Venanzio, FV). Using in vitro intestinal cell models, we evaluated the activity of three different extracts: soaking water, cooking water, and the bioaccessible fraction obtained after mimicking the traditional cooking procedure and gastrointestinal digestion. We demonstrated that FV extracts reduce inflammation and oxidative stress prompted by interleukin 1ß through the inhibition of cyclooxygenase 2 expression and prostaglandin E2 production and through the reduction in reactive oxygen species production and NOX1 levels. The reported data outline the importance of diet in the prevention of human inflammatory diseases. Moreover, they strongly support the necessity to safeguard local biodiversity as a source of bioactive compounds.

Self-delivery nanodrug to manipulate tumor microenvironment for boosting photodynamic cancer immunotherapy.

Immunotherapy has captured attention for its high clinical efficacy. However, its efficacy is limited by inadequate immune activation. Therefore, a platform to activate the immune system and amplify the host's immune response against tumors is urgently needed. Herein, a self-delivery photodynamic nanodrug (VAC@HSA) is reported as inducing immunogenic cell death (ICD), promoting the recruitment of dendritic cells (DCs), and normalizing tumor blood vessels. Firstly, verteporfin with laser assistance releases tumor-associated antigen to induce ICD, while celecoxib downregulates prostaglandin E2 and releases CCL5 to activate DC recruitment. Moreover, vasculature is normalized through axitinib, which contributes to reducing tumor hypoxia and reversing the immunosuppressive effects of vascular endothelial growth factor. This joint action promotes the infiltration of immune effector cells into the tumor. Therefore, the amplified photodynamic nanodrug with excellent biocompatibility effectively inhibits tumor growth and lung metastasis and produces a cascade of immune responses. Our study demonstrates a practically innovative strategy for activating cancer immunotherapy, which can alter the "cold" properties of tumors.

Effect of PGE2 on TT cells viability and division.

Previous studies have shown prostaglandin E2 (PGE2) produced a marked increase in calcitonin secretion in human C-cells derived from medullary thyroid carcinoma. However, it's unclear whether PGE2 can increase the growth of C cells. In this study, we use TT cells as a C cell model to investigate the effect of PGE2 on the growth of C cells. The results revealed that both PGE2 and arachidonic acid (AA) significantly increased the count of TT cells, whereas indomethacin and Dup697 reduced this count. Notably, an increase in the level of AA was associated with an increase in the number of proliferating TT cells, indicating a dose-response relationship. PGE2 and its receptor agonists (sulprostone and butaprost) enhanced the proliferation of TT cells. By contrast, 17-phenyl-trinor-PGE2 exerted no significant effect on TT cell proliferation, whereas L161982 suppressed it. The positive effect of AA on TT cell proliferation was inhibited by indomethacin, NS398, Dup697 (complete inhibition), and SC560. Both PGE2 and AA increased the level of p-STAT5a. The positive effect of AA on p-STAT5a was completely inhibited by Dup697 but not indomethacin, NS398, or SC560. Treatment with indomethacin or Dup697 alone reduced the level of STAT5a in TT cells. AA increased the level of STAT5a, but this effect was inhibited by indomethacin, NS398, and Dup697. Overall, this study confirms the effect of PGE2 on the proliferation of TT cells. This effect is likely mediated through EP2, EP3, and EP4 receptors and associated with an increase in p-STAT5a level within TT cells.

Determinants of joint effusion in tarsocrural osteochondrosis of yearling Standardbred horses.

Tarsocrural osteochondrosis (OCD) is a developmental orthopedic disease commonly affecting young Standardbreds, with different fragment localization and size. Clinically, it is characterized by variable synovial effusion in the absence of lameness, whose determinants are ill-defined. We hypothesized that localization and physical characteristics of the osteochondral fragments like dimensions, multifragmentation, and instability influence joint effusion and correlate with synovial markers of cartilage degradation and inflammation. Clinical data, synovial fluid and intact osteochondral fragments were collected from 79 Standardbred horses, aged between 12 and 18 months, operated for tarsocrural OCD. The severity of tarsocrural joint effusion was assessed semi-quantitatively. The osteochondral fragment site was defined radiographically at the distal intermediate ridge of the tibia (DIRT), medial malleolus (MM) of the tibia, and/or lateral trochlear ridge (LTR) of the talus. Size, stability, and arthroscopic appearance (unique or multi-fragmented aspect) of the fragments were determined intra-operatively. Synovial concentrations of C-terminal cross-linked telopeptides of type II collagen (CTX-II), leukotriene B4 (LTB4), and prostaglandin E2 (PGE2) were quantified. Tarsocrural synovial effusion was significantly affected by localization and stability of the fragments, with MM-located and unstable fragments being associated with highest joint effusion. Concentrations of CTX-II, LTB4, and PGE2 positively correlated with the severity of synovial effusion. This study underlines characteristics of the osteochondral fragments determining higher synovial effusion in OCD-affected tarsocrural joints and suggests both inflammation and extra-cellular matrix degradation are active processes in OCD pathology.

Market Needs and Methodologies Associated with Patient Lipidomic Diagnoses and Analyses.

This chapter conducts an in-depth exploration of the impact of musculoskeletal (MSK) disorders and injuries, with a specific emphasis on their consequences within the older population demographic. It underscores the escalating demand for innovative interventions in MSK tissue engineering. The chapter also highlights the fundamental role played by lipid signaling mediators (LSMs) in tissue regeneration, with relevance to bone and muscle recovery. Remarkably, Prostaglandin E2 (PGE2) emerges as a central orchestrator in these regenerative processes. Furthermore, the chapter investigates the complex interplay between bone and muscle tissues, explaining the important influence exerted by LSMs on their growth and differentiation. The targeted modulation of LSM pathways holds substantial promise as a beneficial way for addressing muscle disorders. In addition to these conceptual understandings, the chapter provides a comprehensive overview of methodologies employed in the identification of LSMs, with a specific focus on the Liquid Chromatography-Mass Spectrometry (LC-MS). Furthermore, it introduces a detailed LC MS/MS-based protocol tailored for the detection of PGE2, serving as an invaluable resource for researchers immersed in this dynamic field of study.

EP2/EP4 targeting prevents tumor-derived PGE2-mediated immunosuppression in cDC2s.

Tumor-derived prostaglandin E2 (PGE2) impairs anti-tumor immunity by priming suppressive functions on various immune cell types, including dendritic cells (DCs). In this way, tumors mediate DC dysfunction and hamper their anti-tumoral activity. PGE2 is known to modulate DC function via signaling through the E-prostanoid receptor type (EP) 2 and EP4. Preclinical studies have demonstrated the therapeutic value of targeting EP2/4 receptor signaling in DCs. Ongoing phase I clinical trials with EP antagonists have shown immunomodulation in cancer patients. However, the systemic drug administration leads to off-target events and subsequent side-effects. To limit the off-target effects of EP targeting, EP2 and EP4 antagonists were encapsulated in polymeric nanoparticles (NPs). In this study we evaluated the efficacy of EP2/4 specific antagonists encapsulated in NPs to protect cDC2s from suppressive effects of tumor-derived PGE2 in different tumor models. We show that tumor-derived PGE2 signals via EP2/4 to mediate the acquisition of a suppressive phenotype of cDC2s. EP2/4 antagonists encapsulated NPs impaired the conversion of cDC2s towards a suppressive state and inhibited the occurrence of suppressive features such as IL-10 production or the ability to expand Tregs. Importantly, the NPs abolished the transition towards this suppressive state in different tumor models: Melanoma-conditioned media, ascites fluid derived from ovarian cancer patients (2D), and upon coculture with colorectal cancer patient-derived organoids (3D). We propose that targeting the PGE2-EP2/4 axis using NPs can achieve immunomodulation in the immune system of cancer patients, alleviate tumor-derived suppression, and thus facilitate the development of potent anti-tumor immunity in cancer patients.

Liposomal quercetin: A promising strategy to combat hepatic insulin resistance and inflammation in type 2 diabetes mellitus.

In type 2 diabetes mellitus, hepatic insulin resistance is intricately associated with oxidative stress and inflammation. Nonetheless, the lack of therapeutic interventions directly targeting hepatic dysfunction represents a notable gap in current treatment options. Flavonoids have been explored due to their potential antidiabetic effects. However, these compounds are associated with low bioavailability and high metabolization. In the present study, four flavonoids, kaempferol, quercetin, kaempferol-7-O-glucoside and quercetin-7-O-glucoside, were studied in a cellular model of hepatic insulin resistance using HepG2 cells. Quercetin was selected as the most promising flavonoid and incorporated into liposomes to enhance its therapeutic effect. Quercetin liposomes had a mean size of 0.12 µm, with an incorporation efficiency of 93 %. Quercetin liposomes exhibited increased efficacy in modulating insulin resistance. This was achieved through the modulation of Akt expression and the attenuation of inflammation, particularly via the NF-κB pathway, as well as the regulation of PGE2 and COX-2 expression. Furthermore, quercetin liposomes displayed a significant advantage over free quercetin in attenuating the production of reactive pro-oxidant species. These findings open new avenues for developing innovative therapeutic strategies to manage diabetes, emphasizing the potential of quercetin liposomes as a promising approach for targeting both hepatic insulin resistance and associated inflammation.

Prostaglandin E2 regulates the plasminogen activator pathway in human endometrial endothelial cells: a new in vitro model to investigate heavy menstrual bleeding.

OBJECTIVE: To study the role of PGE2 in regulating plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) in human primary endometrial endothelial cells (HEECs) from women with normal menstrual bleeding (NMB) and heavy menstrual bleeding (HMB). DESIGN: In vitro study using endometrial endothelial cells. SETTING: Research laboratory setting. PATIENTS: Women with NMB and HMB provided endometrial biopsy samples. INTERVENTIONS: Prostaglandin E2 and PGE2 receptor-selective agonists were administered to cultured HEECs. MAIN OUTCOME MEASURES: Levels of PAI-1 and tPA in NMB-HEECs and HMB-HEECs after treatment with PGE2 and receptor-selective agonists. RESULTS: Prostaglandin E2 increased total PAI-1 levels in NMB-HEECs, but not in HMB-HEECs, which had higher baseline PAI-1 levels. PGE2 receptors (PTGER)1 and PTGER2 agonists increased PAI-1 in NMB-HEECs, whereas PTGER3 and PTGER4 did not. Prostaglandin E2 had no effect on tPA levels in either NMB-HEECs or HMB-HEECs. CONCLUSIONS: Prostaglandin E2, through PTGER1 and PTGER2, regulates the plasminogen activator system in NMB-HEECs, suggesting a role in reducing fibrinolytic activity during normal menstrual cycles. The lack of PGE2 effect and elevated baseline PAI-1 in HMB-HEECs support using this in vitro model to further understand prostaglandin pathways in NMB and HMB.

Prostaglandin E2 depolarises sensory axons in vitro in an ANO1 and Nav1.8 dependent manner.

Prostaglandin E2 (PGE2) is a major contributor to inflammatory pain hyperalgesia, however, the extent to which it modulates the activity of nociceptive axons is incompletely understood. We developed and characterized a microfluidic cell culture model to investigate sensitisation of the axons of dorsal root ganglia neurons. We show that application of PGE2 to fluidically isolated axons leads to sensitisation of their responses to depolarising stimuli. Interestingly the application of PGE2 to the DRG axons elicited a direct and persistent spiking activity propagated to the soma. Both the persistent activity and the membrane depolarisation in the axons are abolished by the EP4 receptor inhibitor and a blocker of cAMP synthesis. Further investigated into the mechanisms of the spiking activity showed that the PGE2 evoked depolarisation was inhibited by Nav1.8 sodium channel blockers but was refractory to the application of TTX or zatebradine. Interestingly, the depolarisation of axons was blocked by blocking ANO1 channels with T16Ainh-A01. We further show that PGE2-elicited axonal responses are altered by the changes in chloride gradient within the axons following treatment with bumetanide a Na-K-2Cl cotransporter NKCC1 inhibitor, but not by VU01240551 an inhibitor of potassium-chloride transporter KCC2. Our data demonstrate a novel role for PGE2/EP4/cAMP pathway which culminates in a sustained depolarisation of sensory axons mediated by a chloride current through ANO1 channels. Therefore, using a microfluidic culture model, we provide evidence for a potential dual function of PGE2 in inflammatory pain: it sensitises depolarisation-evoked responses in nociceptive axons and directly triggers action potentials by activating ANO1 and Nav1.8 channels.

Inflammation assessment and therapeutic monitoring based on highly sensitive and multi-level electrochemical detection of PGE2.

Prostaglandin E2 (PGE2), an eicosane, regulates the physiological activity of inflammatory cells and represents a potential therapeutic target for facilitating tissue repair in vivo. In our work, an electrochemical immunosensor employing Ketjen black-Au nanoparticles (KB-Au) and poly tannic acid nanospheres conjugated with anti-PGE2 polyclonal antibody (PTAN-Ab) was designed to ultra-sensitively analyze PGE2 levels secreted by living cells and tissues. Antibody assembly strategies were explored to achieve signal amplification. Moreover, we studied the therapy effects of docosahexaenoic acid (DHA), arachidonic acid (AA), hyaluronic acid (HA), and small molecule 15-hydroxyprostaglandin dehydrogenase inhibitor (SW033291) on inflammation and evaluated the protective functions of HA and SW033291 in a murine model subjected to colitis induced by dextran sulfate sodium (DSS) using the developed sensor. The sensor exhibited a linear range of 10-5-106 fg/mL and a detection limit (LOD) of 10-5 fg/mL. Fetal bovine serum (FBS) samples were used to achieve high recovery of target analytes. This study not only presents an effective strategy for ultra-sensitively monitoring PGE2 but also provides valuable insights into assessing the degree of inflammation and the therapeutic effect of related drugs. Research on human health monitoring and regenerative medicine could greatly benefit from the findings.