Electrical excitability-the ability to fire and propagate action potentials-is a signature feature of neurons. How neurons become excitable during development and whether excitability is an intrinsic property of neurons remain unclear. Here, we demonstrate that Schwann cells, the most abundant glia in the peripheral nervous system, promote somatosensory neuron excitability during development. We find that Schwann cells secrete prostaglandin E2, which is necessary and sufficient to induce developing somatosensory neurons to express normal levels of genes required for neuronal function, including voltage-gated sodium channels, and to fire action potential trains. Inactivating this signaling pathway in Schwann cells impairs somatosensory neuron maturation, causing multimodal sensory defects that persist into adulthood. Collectively, our studies uncover a neurodevelopmental role for prostaglandin E2 distinct from its established role in inflammation, revealing a cell non-autonomous mechanism by which glia regulate neuronal excitability to enable the development of normal sensory functions.

BACKGROUND: Our previous study indicated that Hcy exacerbated DSS-induced colitis by facilitating the differentiation of intestinal T helper cell 17 (Th17), but the precise mechanism remains unidentified. Therefore, our current research aims to elucidate the signaling pathway through which Hcy promotes the differentiation of Th17 cells.
METHODS: BALb/c mice were randomly assigned into six groups. The model of mice colitis was induced using 3% DSS, while the model of Hyperhomocysteinemia was induced using 1.7% methionine. The concentrations of Hcy and prostaglandin E2 (PGE2) were measured using enzyme-linked immunosorbent assay (ELISA). The protein expressions of cytosolic phospholipase A2 (cPLA2), phosphorylated-cPLA2 (p-cPLA2), cyclooxygenase 2 (COX2), cyclic adenosine monophosphate (cAMP), signal transducer and activator of transcription 3 (STAT3), phosphorylated-STAT3 (p-STAT3), interleukin-17A (IL-17A), and retinoid-related orphan nuclear receptor-γt (RORγt) were assessed using western blot analysis.
RESULTS: Compared to the DSS + HHcy group, the addition of the COX inhibitor did not significantly alter the protein expression of p-PLA2/PLA2, but led to significant decreases in serum PGE2 concentration, cAMP, and p-STAT3/STAT3 protein expression. The protein expressions of p-PLA2/PLA2, COX2, and cAMP upstream of STAT3 inhibitor addition did not exhibit significant changes. However, PGE2 concentration and p-STAT3/STAT3 protein expression were notably reduced. After the COX inhibitor and STAT3 inhibitor added, the protein expression of IL-17A and RORγt and the levels of IL-17A and IL-23R in CD4+ T cells were significantly reduced.
CONCLUSIONS: HHcy aggravated DSS-induced colitis by promoting the differentiation and proliferation of Th17 cells through the PGE2 / STAT3 signaling pathway.

Lung cancer is the leading cause of cancer-related deaths worldwide, with non-small cell lung cancer (NSCLC) constituting approximately 84 % of all lung cancer cases. The role of inflammation in the initiation and progression of NSCLC tumors has been the focus of extensive research. Among the various inflammatory mediators, prostaglandin E2 (PGE2) plays a pivotal role in promoting the aggressiveness of epithelial tumors through multiple mechanisms, including the stimulation of growth, evasion of apoptosis, invasion, and induction of angiogenesis. The Extracellular signal-Regulated Kinase 5 (ERK5), the last discovered member among conventional mitogen-activated protein kinases (MAPK), is implicated in cancer-associated inflammation. In this study, we explored whether ERK5 is involved in the process of tumorigenesis induced by PGE2. Using A549 and PC9 NSCLC cell lines, we found that PGE2 triggers the activation of ERK5 via the EP1 receptor. Moreover, both genetic and pharmacological inhibition of ERK5 reduced PGE2-induced proliferation, migration, invasion and stemness of A549 and PC9 cells, indicating that ERK5 plays a critical role in PGE2-induced tumorigenesis. In summary, our study underscores the pivotal role of the PGE2/EP1/ERK5 axis in driving the malignancy of NSCLC cells in vitro. Targeting this axis holds promise as a potential avenue for developing novel therapeutic strategies aimed at controlling the advancement of NSCLC.

Skin aging results from complex interactions of intrinsic and extrinsic factors, leading to structural and biochemical changes such as wrinkles and dryness. Ultraviolet (UV) irradiation leads to the degradation of hyaluronic acid (HA) in the skin, and the with fragmented HA contributes to inflammation. This study revealed that the synergistic combination of carnosine and retinol (ROL) increases HA production in normal human epidermal keratinocytes (NHEKs) by upregulating hyaluronan synthase 2 (HAS2) gene transcription. Simultaneously, the combined treatment of carnosine and ROL significantly attenuates UVB-induced prostaglandin E2 (PGE2) synthesis in NHEKs. A significant correlation exists between the increase of HA synthesis and the inhibition of PGE2 production. This study suggested that combined treatment of carnosine and ROL can improve skin aging phenotypes associated with UVB irradiation.

Prostaglandin E2 (PGE2) has recently gained attention in the field of regenerative medicine because of the beneficial effects of this molecule on stem cell proliferation and migration. Furthermore, PGE2 has the ability to mitigate immune rejection and fibrosis. In the colon and kidney, PGE2 induces YAP1, a transcription factor critical for cardiac regeneration. Establishing a similar connection in stem cells that can be transplanted in the heart could lead to the development of more effective therapeutics. In this report, we identify the effects of PGE2 on neonatal Islet-1+ stem cells. These stem cells synthesize PGE2, which functions by stimulating the transcription of the extracellular matrix protein Agrin. Agrin upregulates YAP1. Consequently, both YAP1 and Agrin are induced by PGE2 treatment. Our study shows that PGE2 upregulated the expression of both YAP1 and Agrin in Islet-1+ stem cells through the EP4 receptor and stimulated proliferation using the same mechanisms. PGE2 administration further elevated the expression of stemness markers and the matrix metalloproteinase MMP9, a key regulator of remodeling in the extracellular matrix post-injury. The expression of PGE2 in neonatal Islet-1+ cells is a factor which contributes to improving the functional efficacy of these cells for cardiac repair.

E. tournefortii has wound healing properties in folk medicine and 5% infusions are used for stomach ulcers. It is also used in colds, abdominal pain, digestive problems, as an appetite enhancer and antispasmodic. For this purpose, in the study biochemical and histopathological evaluation of the ulcer protective effect of the extract obtained from the E. tournefortii in the indomethacin-induced gastric ulcer model in rats was aimed to develop new strategies in the treatment of ulcers. The phytochemical profile of the plant was elucidated for the first time by LC-HRMS in this study. The results indicate that, in terms of TNF-α, IL-1β, IL-8, IL-6, PGE2, NF-κB, VEGF, NO, COX-1 and COX-2 biochemical parameters, E. tournefortii protects the gastric mucosa to the inflammation, and also modulates the PGE2 pathway, and has a similar effect or even a more positive effect than the reference substance lansoprazole. According to LC-HRMS analysis results, chlorogenic acid, genistein and quinic acid were the main constituents of E. tournefortii extract with 1397.081, 1014.177 and 992.527μg/g extract, respectively. Considering the anti-inflammatory and antioxidant effects of these phenolic components, it is thought that the major components are responsible for the anti-ulcer activity of the E. tournefortii extract.

BACKGROUND: This study investigated the relaxation effect of PGE2 on the ureter and its role in promoting calculi expulsion following calculi development.
METHODS: By using immunofluorescence and Western blot, we were able to locate EP receptors in the ureter. In vitro experiments assessed the impact of PGE2, receptor antagonists, and agonists on ureteral relaxation rate. We constructed a model of ureteral calculi with flowable resin and collected ureteral tissue from postoperative side of the ureter after obstruction surgery. Western blot analysis was used to determine the protein expression levels of EP receptors and the PGE2 terminal synthase mPGES-1. Additionally, PGE2 was added to smooth muscle cells to observe downstream cAMP and PKA changes.
RESULTS: The expression of EP2 and EP4 proteins in ureteral smooth muscle was verified by Western blot analysis. According to immunofluorescence, EP2 was primarily found on the cell membrane, while EP4 was found in the nucleus. In vitro, PGE2 induced concentration-dependent ureteral relaxation. Maximum diastolic rate was 70.94 ± 4.57% at a concentration of 30µM. EP2 antagonists hindered this effect, while EP4 antagonists did not. Obstructed ureters exhibited elevated mPGES-1 and EP2 protein expression (P < 0.01). Smooth muscle cells treated with PGE2 displayed increased cAMP and phosphorylated PKA.
CONCLUSIONS: PGE2 binding to EP2 induces ureteral relaxation through the cAMP-PKA pathway. This will provide a new theoretical basis for the development of new therapeutic approaches for the use of PGE2 in the treatment of ureteral stones.

OBJECTIVE: Cyclooxygenase-2 (COX-2) is involved in different liver diseases, but little is known about the significance of COX-2 in cholestatic injury. This study was designed to elucidate the role of COX-2 expression in hepatocytes during the pathogenesis of obstructive cholestasis.
METHODS: We used genetically modified mice constitutively expressing human COX-2 in hepatocytes. Transgenic mice (hCOX-2-Tg) and their wild-type (Wt) littermates were either subjected to a mid-abdominal laparotomy or common bile duct ligation (BDL) for 2 or 5 days. Then, we explored the mechanisms underlying the role of COX-2 and its derived prostaglandins in liver function, and the synthesis and excretion of bile acids (BA) in response to cholestatic liver injury.
RESULTS: After BDL, hCOX-2-Tg mice showed lower grades of hepatic necrosis and inflammation than Wt mice, in part by a reduced hepatic neutrophil recruitment associated with lower mRNA levels of pro-inflammatory cytokines. Furthermore, hCOX-2-Tg mice displayed a differential metabolic pattern of BA synthesis that led to an improved clearance after BDL-induced accumulation. In addition, an enhanced response to the BDL-induced oxidative stress and hepatic apoptosis was observed. In vitro experiments using hepatic cells that stably express hCOX-2 confirmed the cytoprotective role of prostaglandin E2 against BA toxicity.
CONCLUSIONS: Taken together, our data indicate that constitutive expression of COX-2 in hepatocytes ameliorates cholestatic liver injury in mice by reducing inflammation and cell damage and by modulating BA metabolism, pointing to a role for COX-2 as a defensive response against cholestasis-derived BA accumulation and injury.

The prostaglandin transporter (PGT, SLCO2A1) mediates transport of prostanoids (a.o. prostaglandin E2 (PGE2)) into cells and thereby promotes their degradation. Overexpression of PGT leads to low extracellular PGE2 levels and has been linked to impaired wound healing of diabetic foot ulcers. Inhibition of PGT could thus be beneficial, however, no PGT inhibitors are currently on the market and drug discovery efforts are hampered by lack of high-through screening assays for this transporter. Here we report on a label-free impedance-based assay for PGT that measures transport activity through receptor activation (TRACT) utilizing prostaglandin E2 receptor subtype EP3 and EP4 that are activated by PGE2. We found that induction of PGT expression on HEK293-JumpIn-SLCO2A1 cells that also express EP3 and EP4 leads to an over 10-fold reduction in agonistic potency of PGE2. PGE2 potency could be recovered upon inhibition of PGT-mediated PGE2 uptake with PGT inhibitors olmesartan and T26A, the potency of which could be established as well. Moreover, the TRACT assay enabled the assessment of transport function of PGT natural variants. Lastly, HUVEC cells endogenously expressing prostanoid receptors and PGT were exploited to study wound healing properties of PGE2 and T26A in real-time using a novel impedance-based scratch-induced wound healing assay. These novel impedance-based assays will advance PGT drug discovery efforts and pave the way for the development of PGT-based therapies.

BACKGROUND: A large number of studies have shown that leptin plays an important role in the regulation of fertility via the hypothalamus-pituitary-gonad axis. However, its peripheral function in epididymis was still elusive.
OBJECTIVE: The purpose of this study was to determine the pro-secretion effect of leptin on the rat epididymal epithelium.
METHODS: In the present study, real-time quantitative polymerase chain reaction, western blot, and immunohistochemical analysis were employed to detect the expression pattern of leptin receptors in rat epididymis. The pro-secretion effect of leptin on epididymal epithelial cells was measured by short-circuit current, and the prostaglandin E2 and cyclic adenosine monophosphate level was evaluated by enzyme-linked immunosorbent assay.
RESULTS: We verified that the leptin receptor was located on the epididymal epithelium, with a relatively high expression level in corpus and cauda epididymis. Ussing chamber experiments showed that leptin stimulated a significant rise of the short-circuit current in rat epididymal epithelial cells, which could be abolished by the specific leptin receptor antagonist peptide Allo-aca, or by removing the ambient Cl- and HCO3 -. Furthermore, the leptin-stimulated short-circuit current response could be abrogated by blocking the apical cystic fibrosis transmembrane regulator or the basolateral Na+-K+-2Cl- cotransporter. Our pharmacological experiments manifested that interfering with the prostaglandin H synthase-2-prostaglandin E2-EP2/EP4-adenylate cyclase pathways could significantly blunt the cystic fibrosis transmembrane regulator-mediated anion secretion induced by leptin. The enzyme-linked immunosorbent assay demonstrated that leptin could induce a substantial increase in prostaglandin E2 release and cyclic adenosine monophosphate synthesis of primary cultured rat cauda epididymal epithelial cells. Our data also suggested that JAK2, ERK, and PI3K-dependent phosphorylation may be involved in the activation of prostaglandin H synthase-2 and the subsequent prostaglandin E2 production.
CONCLUSIONS: The present study demonstrated the pro-secretion function of leptin in rat epididymal epithelium via the activation of cystic fibrosis transmembrane regulator and Na+-K+-2Cl- cotransporter, which was dependent on the paracrine/autocrine prostaglandin E2 stimulated EP2/EP4-adenylate cyclase pathways, and thus contributed to the formation of an appropriate microenvironment essential for sperm maturation.