[Role of COX-2/PGE2/EP4 Axis-induced Macrophage Functional Activation 
in NSCLC Development].

BACKGROUND: Tumor microenvironment (TME) is one of the important factors in tumorigenesis and progression, in which tumor-associated macrophages (TAMs) play an important role in non-small cell lung cancer (NSCLC) progression. However, the mechanism of TAMs in NSCLC progression remains unclear, so this study aimed to investigate the role of TAMs in NSCLC progression and to find potential therapeutic targets. METHODS: Gene Expression Profiling Interactive Analysis (GEPIA) database was used to analyze the expression of prostaglandin E2 receptor 4 (EP4) mRNA in NSCLC and normal lung tissues; the protein expression levels of cyclooxygenase-2 (COX-2), EP4, cluster of differentiation 86 (CD86), CD163 and CD31 were detected by immunohistochemistry (IHC) in 120 NSCLC tissues and 24 paracancerous tissues specimens. The nude mouse lung adenocarcinoma cell A549 and macrophage RAW264.7 co-transplanted tumor model was established. And the samples were collected by gavage with EP4 inhibitor E7046, and then stained with hematoxylin-eosin (HE), IHC, and immunofluorescence (IF), and then detected by Western blot for the epithelial mesenchymal transformation (EMT) of the tumor tissues of the nude mice in each group. Western blot was used to detect the expressions of EMT related protiens in each group of nude mice; full-length transcriptome sequencing was used to screen the key genes causing liver metastasis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed. RESULTS: EP4 mRNA expression level in NSCLC tissues was generally lower than that in normal lung tissues (P<0.05); COX-2, EP4, CD163, CD31 proteins were differentially expressed in NSCLC tissues and adjacent tissues, and differences were observed in many clinicopathological parameters of NSCLC patients; RAW264.7 shortened the latency period of tumorigenesis of A549 and promoted the proliferation of tumors and liver metastasis of tumors, and E7046 could reduce tumor cell proliferation activity, tumor tissue vascular density and M2-type macrophage infiltration in nude mice; IF staining showed that macrophages were mainly distributed around the metastatic foci of tumors; Western blot results showed that compared with A549 alone transplantation group, the relative expression of E-cadherin protein in tumor tissues of mice in A549 and RAW264.7 co-transplantation group was significantly decreased, and the difference was statistically significant (P<0.05), while the relative expression of N-cadherin protein was up-regulated, but the difference was not statistically significant (P>0.05); the main pathways enriched in the differential genes of the full-length transcriptome were the PI3K-AKT and MAPK signaling pathways. CONCLUSIONS: During NSCLC development, the COX-2/PGE2/EP4 axis may promote tumor progression by inducing macrophage functional activation, and EP4 may be a potential new target for tumor immunotherapy. This study provides new perspectives and ideas for in-depth exploration of the mechanisms of NSCLC development, as well as a theoretical basis for the development of new therapeutic strategies for NSCLC.

Post-resolution macrophages shape long-term tissue immunity and integrity in a mouse model of pneumococcal pneumonia.

Resolving inflammation is thought to return the affected tissue back to homoeostasis but recent evidence supports a non-linear model of resolution involving a phase of prolonged immune activity. Here we show that within days following resolution of Streptococcus pneumoniae-triggered lung inflammation, there is an influx of antigen specific lymphocytes with a memory and tissue-resident phenotype as well as macrophages bearing alveolar or interstitial phenotype. The transcriptome of these macrophages shows enrichment of genes associated with prostaglandin biosynthesis and genes that drive T cell chemotaxis and differentiation. Therapeutic depletion of post-resolution macrophages, inhibition of prostaglandin E2 (PGE2) synthesis or treatment with an EP4 antagonist, MF498, reduce numbers of lung CD4+/CD44+/CD62L+ and CD4+/CD44+/CD62L-/CD27+ T cells as well as their expression of the α-integrin, CD103. The T cells fail to reappear and reactivate upon secondary challenge for up to six weeks following primary infection. Concomitantly, EP4 antagonism through MF498 causes accumulation of lung macrophages and marked tissue fibrosis. Our study thus shows that PGE2 signalling, predominantly via EP4, plays an important role during the second wave of immune activity following resolution of inflammation. This secondary immune activation drives local tissue-resident T cell development while limiting tissue injury.

Phytochemical Composition, Anti-Inflammatory Property, and Anti-Atopic Effect of Chaetomorpha linum Extract.

Utilizing plant-based resources, particularly their by-products, aligns with sustainability principles and circular bioeconomy, contributing to environmental preservation. The therapeutic potential of plant extracts is garnering increasing interest, and this study aimed to demonstrate promising outcomes from an extract obtained from an underutilized plant waste. Chaetomorpha linum, an invasive macroalga found in the Orbetello Lagoon, thrives in eutrophic conditions, forming persistent mats covering approximately 400 hectares since 2005. The biomass of C. linum undergoes mechanical harvesting and is treated as waste, requiring significant human efforts and economic resources-A critical concern for municipalities. Despite posing challenges to local ecosystems, the study identified C. linum as a natural source of bioactive metabolites. Phytochemical characterization revealed lipids, amino acids, and other compounds with potential anti-inflammatory activity in C. linum extract. In vitro assays with LPS-stimulated RAW 264.7 and TNF-α/IFN-γ-stimulated HaCaT cells showed the extract inhibited reactive oxygen species (ROS), nitric oxide (NO), and prostaglandin E2 (PGE2) productions, and reduced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions via NF-κB nuclear translocation, in RAW 264.7 cells. It also reduced chemokines (TARC/CCL17, RANTES/CCL5, MCP-1/CCL2, and IL-8) and the cytokine IL-1ß production in HaCaT cells, suggesting potential as a therapeutic candidate for chronic diseases like atopic dermatitis. Finally, in silico studies indicated palmitic acid as a significant contributor to the observed effect. This research not only uncovered the untapped potential of C. linum but also laid the foundation for its integration into the circular bioeconomy, promoting sustainable practices, and innovative applications across various industries.

The importance of mechanosensitive cell mediated prostaglandin and nitric oxide synthesis in the pathogenesis of apical periodontitis: comparative with chronic periodontitis.

OBJECTIVES: Mechano-sensitive odontoblast cells, which sense mechanical loading and various stresses in the tooth structure, synthesize early signaling molecules such as prostaglandin E2 (PGE2) and nitric oxide (NO) as an adaptive response. It is thought that these synthesized molecules can be used for the diagnosis and treatment of periodontal and periapical diseases. The aim of this study was to investigate the relationship between the severity of apical periodontitis (AP) and chronic periodontitis (CP) and serum (s) TNF-α, IL-10, PGE2 and NO levels, as well as PGE2 and NO levels in gingival crevicular fluid (GCF) samples. MATERIALS & METHODS: A total of 185 subjects were divided into three categories: AP group (n = 85), CP group (n = 50) and healthy control group (n = 50). The AP group was divided into 3 subgroups according to abscess scoring (AS-PAI 1, 2 and 3) based on the periapical index. The CP group was divided into 4 subgroups according to the periodontitis staging system (PSS1, 2,3 and 4). After recording the demographic and clinical characteristics of all participants, serum (s) and gingival crevicular fluid (GCF) samples were taken. TNF-α, IL-10, PGE2 and NO levels were measured in these samples. RESULTS: Unlike serum measurements (sTNF-α, sIL-10, sNO and sPGE2), GCF-NO and GCF-PGE levels of the AP group were significantly higher than the control group in relation to abscess formation (54.4 ± 56.3 vs. 22.5 ± 12.6 µmol/mL, p < 0.001 and 100 ± 98 vs. 41 ± 28 ng/L, p < 0.001, respectively). Confirming this, the GCF-NO and GCF-PGE levels of the AS-PAI 1 group, in which abscesses have not yet formed, were found to be lower than those in AS-PAI 2 and 3, which are characterized by abscess formation [(16.7(3.7-117.8), 32.9(11.8-212.8) and 36.9(4.3-251.6) µmol/mL, p = 0,0131; 46.0(31.4-120.0), 69.6(40.3-424.2) and 74.4(32.1-471.0) ng/L, p = 0,0020, respectively]. Consistent with the increase in PSS, the levels of sTNF [29.8 (8.2-105.5) vs. 16.7(6.3-37.9) pg/mL, p < 0.001], sIL-10 [542(106-1326) vs. 190(69-411) pg/mL, p < 0.001], sNO [182.1(36.3-437) vs. 57.0(15.9-196) µmol/mL, p < 0.001], sPGE2 [344(82-1298) vs. 100(35-1178) ng/L, p < 0.001], GCF-NO [58.9 ± 33.6 vs. 22.5 ± 12.6 ng/L, p < 0.001] and GCF-PGE2 [ 99(37-365) vs. 30(13-119), p < 0.001] in the CP group were higher than the control group. Comparison ROC analysis revealed that the GCF-PGE2 test had the best diagnostic value for both AP and CP (sensitivity: 94.1 and 88.0; specificity: 64.0 and 78.0, respectively; p < 0.001). CONCLUSIONS: GCF-PE2 and GCF-NO have high diagnostic value in the determination of AP and CP, and can be selected as targets to guide treatment. In addition, the measurements of PGE2 and NO in GCF can be used as an important predictor of pulpal necrosis leading to abscess in patients with AP. CLINICAL RELEVANCE: In this article, it is reported that syntheses of early signaling molecules such as PGE2 and NO can be used for the diagnosis and treatment target of periapical and periodontal infections.

Prostaglandin E2 in the Tumor Microenvironment, a Convoluted Affair Mediated by EP Receptors 2 and 4.

The involvement of the prostaglandin E2 (PGE2) system in cancer progression has long been recognized. PGE2 functions as an autocrine and paracrine signaling molecule with pleiotropic effects in the human body. High levels of intratumoral PGE2 and overexpression of the key metabolic enzymes of PGE2 have been observed and suggested to contribute to tumor progression. This has been claimed for different types of solid tumors, including, but not limited to, lung, breast, and colon cancer. PGE2 has direct effects on tumor cells and angiogenesis that are known to promote tumor development. However, one of the main mechanisms behind PGE2 driving cancerogenesis is currently thought to be anchored in suppressed antitumor immunity, thus providing possible therapeutic targets to be used in cancer immunotherapies. EP2 and EP4, two receptors for PGE2, are emerging as being the most relevant for this purpose. This review aims to summarize the known roles of PGE2 in the immune system and its functions within the tumor microenvironment. SIGNIFICANCE STATEMENT: Prostaglandin E2 (PGE2) has long been known to be a signaling molecule in cancer. Its presence in tumors has been repeatedly associated with disease progression. Elucidation of its effects on immunological components of the tumor microenvironment has highlighted the potential of PGE2 receptor antagonists in cancer treatment, particularly in combination with immune checkpoint inhibitor therapeutics. Adjuvant treatment could increase the response rates and the efficacy of immune-based therapies.

High-mannose glycans from Schistosoma mansoni eggs are important for priming of Th2 responses via Dectin-2 and prostaglandin E2.

The parasitic helminth Schistosoma mansoni is a potent inducer of type 2 immune responses by stimulating dendritic cells (DCs) to prime T helper 2 (Th2) responses. We previously found that S. mansoni soluble egg antigens (SEA) promote the synthesis of Prostaglandin E2 (PGE2) by DCs through ERK-dependent signaling via Dectin-1 and Dectin-2 that subsequently induces OX40L expression, licensing them for Th2 priming, yet the ligands present in SEA involved in driving this response and whether specific targeting of PGE2 synthesis by DCs could affect Th2 polarization are unknown. We here show that the ability of SEA to bind Dectin-2 and drive ERK phosphorylation, PGE2 synthesis, OX40L expression, and Th2 polarization is impaired upon cleavage of high-mannose glycans by Endoglycosidase H treatment. This identifies high-mannose glycans present on glycoproteins in SEA as important drivers of this signaling axis. Moreover, we find that OX40L expression and Th2 induction are abrogated when microsomal prostaglandin E synthase-1 (mPGES) is selectively inhibited, but not when a general COX-1/2 inhibitor is used. This shows that the de novo synthesis of PGE2 is vital for the Th2 priming function of SEA-stimulated DCs as well as points to the potential existence of other COX-dependent lipid mediators that antagonize PGE2-driven Th2 polarization. Lastly, specific PGE2 inhibition following immunization with S. mansoni eggs dampened the egg-specific Th cell response. In summary, our findings provide new insights in the molecular mechanisms underpinning Th2 induction by S. mansoni and identify druggable targets for potential control of helminth driven-Th2 responses.

Exposure to nicotine regulates prostaglandin E2 secretion and autophagy of granulosa cells to retard follicular maturation in mammals.

Exposure to nicotine by cigarette smoking have shown strongly defectives on the physiological function of ovaries, which in turn leads to disorders of fertility in women. However, the potential molecular mechanisms remain to be elucidated. In this study, we notably found that nicotine was likely to specifically raise the expression of histone deacetylase 3 (HDAC3) to promote the apoptosis and autophagy of granulosa cells (GCs) and block follicular maturation. Moreover, prostaglandin E2 (PGE2) inhibited the apoptosis of GCs and facilitated follicular maturation, and nicotine appeared to inhibit PGE2 secretion by freezing the expression of cyclooxygenase 1 (COX1), which was the rate-limiting and essential enzyme for PGE2 synthesis. Epigenetically, the nicotine was observed to diminish the histone H3 lysine 9 acetylation (H3K9ac) level and compact the chromatin accessibility in -1776/-1499 bp region of COX1 by evoking the expression of HDAC3, with the deactivated Cas9-HDAC3/sgRNA system. Mechanistically, the COX1 protein was found to pick up and degrade the autophagy related protein beclin 1 (BECN1) to control the autophagy of GCs. These results provided a potential new molecular therapy to recover the damage of female fertility induced by nicotine from cigarette smoking.

The histamine H4 receptor antagonist 1-[(5-chloro-2,3-dihydro-1-benzofuran-2-yl)methyl]-4-methyl-piperazine(LINS01007) prevents the development of DSS-induced colitis in mice.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with growing incidence worldwide. Our group reported the compound 5-choro-1-[(2,3-dihydro-1-benzofuran-2-yl)methyl]piperazine (LINS01007) as H4R antagonist (pKi 6.2) and therefore the effects and pharmacological efficacy on a DSS-induced mice model of UC were assessed in this work. Experimental acute colitis was induced in male BALB/c mice (n = 5-10) by administering 3 % DSS in the drinking water for six days. The test compound LINS01007 was administered daily i.p. (5 mg/kg) and compared to control group without treatment. Body weight, water and food consumption, and the presence of fecal blood were monitored during 7-day treatment period. The levels of inflammatory markers (PGE2, COX-2, IL-6, NF-κB and STAT3) were also analyzed. Animals subjected to the acute colitis protocol showed a reduction in water and food intake from the fourth day (p < 0.05) and these events were prevented by LINS01007. Histological signs of edema, hyperplasia and disorganized intestinal crypts, as well as neutrophilic infiltrations, were found in control mice while these findings were significantly reduced in animals treated with LINS01007. Significant reductions in the levels of PGE2, COX-2, IL-6, NF-κB and STAT3 were observed in the serum and tissue of treated animals. The results demonstrated the significant effects of LINS01007 against DSS-induced colitis, highlighting the potential of H4R antagonism as promising treatment for this condition.

PGE2 limits effector expansion of tumour-infiltrating stem-like CD8+ T cells.

Cancer-specific TCF1+ stem-like CD8+ T cells can drive protective anticancer immunity through expansion and effector cell differentiation1-4; however, this response is dysfunctional in tumours. Current cancer immunotherapies2,5-9 can promote anticancer responses through TCF1+ stem-like CD8+ T cells in some but not all patients. This variation points towards currently ill-defined mechanisms that limit TCF1+CD8+ T cell-mediated anticancer immunity. Here we demonstrate that tumour-derived prostaglandin E2 (PGE2) restricts the proliferative expansion and effector differentiation of TCF1+CD8+ T cells within tumours, which promotes cancer immune escape. PGE2 does not affect the priming of TCF1+CD8+ T cells in draining lymph nodes. PGE2 acts through EP2 and EP4 (EP2/EP4) receptor signalling in CD8+ T cells to limit the intratumoural generation of early and late effector T cell populations that originate from TCF1+ tumour-infiltrating CD8+ T lymphocytes (TILs). Ablation of EP2/EP4 signalling in cancer-specific CD8+ T cells rescues their expansion and effector differentiation within tumours and leads to tumour elimination in multiple mouse cancer models. Mechanistically, suppression of the interleukin-2 (IL-2) signalling pathway underlies the PGE2-mediated inhibition of TCF1+ TIL responses. Altogether, we uncover a key mechanism that restricts the IL-2 responsiveness of TCF1+ TILs and prevents anticancer T cell responses that originate from these cells. This study identifies the PGE2-EP2/EP4 axis as a molecular target to restore IL-2 responsiveness in anticancer TILs to achieve cancer immune control.

PGE2 inhibits TIL expansion by disrupting IL-2 signalling and mitochondrial function.

Expansion of antigen-experienced CD8+ T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer1. Interleukin-2 (IL-2) acts as a key regulator of CD8+ cytotoxic T lymphocyte functions by promoting expansion and cytotoxic capability2,3. Therefore, it is essential to comprehend mechanistic barriers to IL-2 sensing in the tumour microenvironment to implement strategies to reinvigorate IL-2 responsiveness and T cell antitumour responses. Here we report that prostaglandin E2 (PGE2), a known negative regulator of immune response in the tumour microenvironment4,5, is present at high concentrations in tumour tissue from patients and leads to impaired IL-2 sensing in human CD8+ TILs via the PGE2 receptors EP2 and EP4. Mechanistically, PGE2 inhibits IL-2 sensing in TILs by downregulating the IL-2Rγc chain, resulting in defective assembly of IL-2Rß-IL2Rγc membrane dimers. This results in impaired IL-2-mTOR adaptation and PGC1α transcriptional repression, causing oxidative stress and ferroptotic cell death in tumour-reactive TILs. Inhibition of PGE2 signalling to EP2 and EP4 during TIL expansion for ACT resulted in increased IL-2 sensing, leading to enhanced proliferation of tumour-reactive TILs and enhanced tumour control once the cells were transferred in vivo. Our study reveals fundamental features that underlie impairment of human TILs mediated by PGE2 in the tumour microenvironment. These findings have therapeutic implications for cancer immunotherapy and cell therapy, and enable the development of targeted strategies to enhance IL-2 sensing and amplify the IL-2 response in TILs, thereby promoting the expansion of effector T cells with enhanced therapeutic potential.

Radix Sophorae Flavescentis of Sophora flavescens Aiton inhibits LPS-induced macrophage pro-inflammatory response via regulating CFHR2 expression.

ETHNOPHARMACOLOGICAL RELEVANCE: Long-term chronic inflammation often leads to chronic diseases. Although Sophora flavescens has been shown to have anti-inflammatory properties, its detailed molecular mechanism is still unknown. AIM OF STUDY: This study investigated the effect of Radix Sophorae Flavescentis on the LPS-induced inflammatory response in macrophages. MATERIALS AND METHODS: LPS was used to induce the peritoneal macrophages to simulate the inflammatory environment in vitro. Different concentrations of Radix Sophorae Flavescentis-containing (medicated) serum were used for intervention. The peritoneal macrophages were identified by using hematoxylin-eosin and immunofluorescence staining. ELISA was used to measure the TNF-α and IL-6 expression to determine the concentration of LPS. ELISA and Western blot (WB) were used to detect the PGE2 and CFHR2 expression in each group, respectively. The lentiviral vector for interference and overexpression of the CFHR2 gene was constructed, packaged, and transfected into LPS-induced macrophages. The transfection efficiency was verified by WB. Then, ELISA was used to detect the TNF-α, PGE2, and IL-6 expression. WB was used to detect the CFHR2, iNOS, COX-2, TLR2, TLR4, IFN-γ, STAT1, and p-STAT1 expression. RESULTS: The primary isolated cells were identified as macrophages. The LPS-treated macrophages exhibited significantly higher expression of PGE2 and CFHR2, and the inflammatory factors TNF-α and IL-6, as well as iNOS, COX-2, TLR2, TLR4, IFN-γ, STAT1, and p-STAT1 expression compared with the control group (P < 0.05). The TNF-α, PGE2, and IL-6 levels, as well as CFHR2, iNOS, COX-2, TLR2, TLR4, IFN-γ, STAT1, and p-STAT1 expression were considerably lower in the LPS-induced+10% medicated-serum group, LPS-induced+20% medicated-serum group, and shCFHR interference group compared with the LPS group (P < 0.05). CONCLUSION: Radix Sophorae Flavescentis might mediate CFHR2 expression and play an important role in inhibiting the LPS-induced pro-inflammatory response of macrophages. Radix Sophorae Flavescentis could be a potential treatment for LPS-induced related inflammatory diseases.

Physiological healing of chronic gastric ulcer is not impaired by the hydrogen sulphide (H2S)-releasing derivative of acetylsalicylic acid (ATB-340): functional and proteomic approaches.

Gastric ulcers affect approx. 10% of population. Non-steroidal anti-inflammatory drugs (NSAIDs), including acetylsalicylic acid (ASA) predispose to or impair the physiologically complex healing of pre-existing ulcers. Since H2S is an endogenous cytoprotective molecule, we hypothesized that new H2S-releasing ASA-derivative (ATB-340) could overcome pathological impact of NSAIDs on GI regeneration.Clinically translational gastric ulcers were induced in Wistar rats using state-of-the-art microsurgical model employing serosal application of acetic acid. This was followed by 9 days long i.g. daily treatment with vehicle, ATB-340 (6-24 mg/kg) or equimolar ASA doses (4-14 mg/kg). Ulcer area was assessed macro- and microscopically. Prostaglandin (PG)E2  levels, indicating pharmacological activity of NSAIDs and 8-hydroxyguanozine content, reflecting nucleic acids oxidation in serum/gastric mucosa, were determined by ELISA. Qualitative and/or quantitative pathway-specific alterations at the ulcer margin were evaluated using real-time PCR and mass spectrometry-based proteomics.ASA, unlike ATB-340, dose-dependently delayed/impaired gastric tissue recovery, deregulating 310 proteins at the ulcer margin, including Ras signalling, wound healing or apoptosis regulators. ATB-340 maintained NSAIDs-specific cyclooxygenase-inhibiting capacity on systemic and GI level but in time-dependent manner. High dose of ATB-340 (24 mg/kg daily), but not ASA, decreased nucleic acids oxidation and upregulated anti-oxidative/anti-inflammatory heme oxygenase-1, 24-dehydrocholesterol reductase or suppressor of cytokine signalling (SOCS3) at the ulcer margin.Thus, ASA impairs the physiological healing of pre-existing gastric ulcers, inducing the extensive molecularly functional and proteomic alterations at the wound margin. H2S-releasing ATB-340 maintains the target activity of NSAIDs with limited impact on gastric PGE2 signalling and physiological GI regeneration, enhancing anti-inflammatory and anti-oxidative response, and providing the pharmacological advantage.

Terminalia ferdinandiana Exell. extracts reduce pro-inflammatory cytokine and PGE2 secretion, decrease COX-2 expression and down-regulate cytosolic NF-κB levels.

Based on their high antioxidant capacity and noteworthy phytochemistry, Terminalia ferdinandiana fruit and leaves have attracted considerable recent interest for their therapeutic potential. Whilst those studies have reported a variety of therapeutic properties for the fruit, the anti-inflammatory potential of T. ferdinandiana has been largely neglected and the leaves have been almost completely ignored. This study investigated the immune-modulatory and anti-inflammatory properties of T. ferdinandiana fruit and leaf extracts by evaluating their inhibition of multiple pro- and anti-inflammatory cytokines and chemokines secretion in lipopolysaccharide (LPS)-stimulated and unstimulated RAW 264.7 macrophages using multiplex bead immunoassays and ELISA assays. The methanolic extracts were particularly good immune-modulators, significantly inhibiting the secretion of all the cytokines and chemokines tested. Indeed, the methanolic extracts completely inhibited IL-10, IFN-γ, IL-1ß, IL-6, MCP-1, and MIP-2a secretion, and almost completely inhibited the secretion of TNF-α. In addition, the methanolic T. ferdinandiana extracts also significantly inhibited cytosolic COX-2 levels (by 87-95%) and the synthesis of the PGE2 (by ~ 98%). In contrast, the methanolic extracts stimulated LTB4 secretion by ~ 60-90%, whilst the aqueous extracts significantly inhibited LTB4 secretion (by ~ 27% each). Exposure of RAW 264.7 cells to the methanolic T. ferdinandiana extracts also significantly down-regulated the cytosolic levels of NF-κB by 33-44%, indicating that the immune-modulatory and anti-inflammatory properties of the extracts may be regulated via a decrease in NF-κB transcription pathways. Taken together, these results demonstrate potent anti-inflammatory properties for the extracts and provide insights into their anti-inflammatory mechanisms.

Role of prostaglandin E2 and its receptors in chronic liver disease.

Chronic liver disease (CLD) is a major global health burden in terms of growing morbidity and mortality. Although many conditions can cause CLD, leading to cirrhosis and hepatocellular carcinoma (HCC), viral hepatitis, drug-induced liver injury (DILI), alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the most common culprits. Prostaglandin E2 (PGE2), produced in the liver, is an important lipid mediator derived from the ω-6 polyunsaturated fatty acid, arachidonic acid, and plays a critical role in hepatic homeostasis. The physiological effects of PGE2 are mediated through four classes of E-type prostaglandin (EP) receptors, namely EP1, EP2, EP3 and EP4. In recent years, an increasing number of studies has been done to clarify the effects of PGE2 and EP receptors in regulating liver function and the pathogenesis of CLD to create a new potential clinical impact. In this review, we overview the biosynthesis and regulation of PGE2 and discuss the role of its synthesizing enzymes and receptors in the maintenance of normal liver function and the development and progress of CLD. We also discuss the potential of the PGE2-EP receptors system in treating CLD with various etiologies.

[The relationship between the expression of PGE2 and COX-2 and the osteogenic activity and oxygen level of alveolar bone].

PURPOSE: To study the relationship between the expression of prostaglandin E2 (PGE2) and cyclooxygenase-2 (COX-2) and the osteogenic activity and oxygen level of alveolar bone. METHODS: The alveolar bones of 56 patients with chronic periodontitis who received dental treatment from March 2021 to March 2023 were collected as the experimental (periodontitis) group, and the healthy alveolar bones of 53 patients who received dental treatment during the same period were selected as the control group. The osteoblasts were cultured by tissue block culture, and modified Kaplow's alkaline phosphatase (ALP) staining was used to identify the cells. COX-2, PGE2 and osteoclastogenesis inhibitory factor (OPG) receptor activator of nuclear factor-κb ligand (RANKL) and other indicators were determined by ELISA. PGE2, COX-2, OPG, internal oxygen level, ALP, RANKL and their correlation were compared between the two groups. Statistical analysis was performed with SPSS 27.0 software package. RESULTS: PGE2, COX-2 and RANKL in periodontitis group were significantly higher than those in the control group, but OPG, internal oxygen level and ALP were significantly lower than those in the control group (P＜0.05). PGE2 and COX2 were highly positively correlated with OPG, internal oxygen level and ALP, but were highly positively correlated with RANKL(P＜0.05). CONCLUSIONS: The expression of PGE2 and COX-2 is highly negatively correlated with ALP and oxygen levels. Clinical treatment may consider increasing oxygen levels, increasing oxygen partial pressure, and regulating ALP levels by drugs, so as to change the inflammatory condition of periodontitis or other dental diseases.

Nicotinamide Riboside Augments Human Macrophage Migration via SIRT3-Mediated Prostaglandin E2 Signaling.

NAD+ boosting via nicotinamide riboside (NR) confers anti-inflammatory effects. However, its underlying mechanisms and therapeutic potential remain incompletely defined. Here, we showed that NR increased the expression of CC-chemokine receptor 7 (CCR7) in human M1 macrophages by flow cytometric analysis of cell surface receptors. Consequently, chemokine ligand 19 (CCL19, ligand for CCR7)-induced macrophage migration was enhanced following NR administration. Metabolomics analysis revealed that prostaglandin E2 (PGE2) was increased by NR in human monocytes and in human serum following in vivo NR supplementation. Furthermore, NR-mediated upregulation of macrophage migration through CCL19/CCR7 was dependent on PGE2 synthesis. We also demonstrated that NR upregulated PGE2 synthesis through SIRT3-dependent post-transcriptional regulation of cyclooxygenase 2 (COX-2). The NR/SIRT3/migration axis was further validated using the scratch-test model where NR and SIRT3 promoted more robust migration across a uniformly disrupted macrophage monolayer. Thus, NR-mediated metabolic regulation of macrophage migration and wound healing may have therapeutic potential for the topical management of chronic wound healing.

Effect of heat exposure on prostaglandin production and expression of COX-2, PGES, PGFS, ITGAV and LGALS15 mRNAs in endometrial epithelial cells of buffalo (Bubalus bubalis).

BACKGROUND: Early embryonic mortality is one of the major intriguing factors of reproductive failure that causes considerable challenge to the mammalian cell biologists. Heat stress is the major factor responsible for reduced fertility in farm animals. The present study aimed to investigate the influence of heat stress on prostaglandin production and the expression of key genes, including COX-2, PGES, PGFS, ITGAV and LGALS15, in buffalo endometrial epithelial cells. METHODS AND RESULTS: Buffalo genitalia containing ovaries with corpus luteum (CL) were collected immediately post-slaughter. The stages of the estrous cycle were determined based on macroscopic observations of the ovaries. Uterine lumens of the mid-luteal phase (days 6-10 of the estrous cycle) were washed and treated with trypsin to isolate epithelial cells, which were then cultured at control temperature (38.5 °C for 24 h) or exposed to elevated temperatures [38.5 °C for 6 h, 40.5 °C for 18 h; Heat Stressed (HS)]. The supernatant and endometrial epithelial cells were collected at various time points (0, 3, 6, 12, and 24 h) from both the control and treatment groups. Although heat stress (40.5 °C) significantly (P < 0.05) increased COX-2, PGES, and PGFS transcripts in epithelial cells but it did not affect the in vitro production of PGF2α and PGE2. The expression of ITGAV and LGALS15 mRNAs in endometrial epithelial cells remained unaltered under elevated temperature conditions. CONCLUSION: It can be concluded that elevated temperature did not directly modulate prostaglandin production but, it promoted the expression of COX-2, PGES and PGFS mRNA in buffalo endometrial epithelial cells.

[miR-515-5p targeting Toll-like receptor 4 regulates myeloid differentiation primary response gene 88/nuclear factor-kappa B pathway to inhibit apoptosis and inflammatory response of osteoarthritis chondrocytes].

Objective: To explore the molecular mechanism of miR-515-5p in inhibiting chondrocyte apoptosis and alleviating inflammatory response in osteoarthritis (OA). Methods: Human cartilage cell line C28/I2 was cultured in vitro and treated with 10 ng/mL interleukin 1ß (IL-1ß) for 24 hours to construct an in vitro OA model. C28/I2 cells were transfected with miR mimics, mimics negative control (NC), over expression (oe)-NC, and oe-Toll-like receptor 4 (TLR4), respectively, and then treated with 10 ng/mL IL-1ß for 24 hours to establish OA model. Cell proliferation capacity was detected by cell counting kit 8 and 5-Ethynyl-2'-deoxyuridine, cell apoptosis and cell cycle were detected by flow cytometry, and B-cell lymphoma 2 protion (Bcl-2), Bcl-2-associated X protein (Bax), cleaved-Caspase-3, TLR4, myeloid differentiation primary response gene 88 (MyD88), p65 and phosphorylated p65 (p-p65) protein expression levels were detected by Western blot. Real-time fluorescence quantitative PCR was used to detect mRNA expression levels of miR-515-5p and TLR4, and ELISA was used to detect pro-inflammatory factor prostaglandin E2 (PGE2), tumor necrosis factor α (TNF -α), and IL-6 levels in cell supernatant. The potential binding sites between miR-515-5p and TLR4 were predicted by BiBiServ2 database, and the targeting relationship between miR-515-5p and TLR4 was verified by dual luciferase reporting assay. Results: After the treatment of C28/I2 cells with IL-1ß, the expressions of miR-515-5p and Bcl-2 protein and the proliferation ability of C28/I2 cells significantly reduced. The expression levels of Bax and cleaved-Caspase-3 protein, the levels of pro-inflammatory factors (PGE2, TNF-α, IL-6) in the supernatant of C28/I2 cells, and the apoptosis of C28/I2 cells significantly increased. In addition, the proportion of the cells at S phase and G 2 phase decreased significantly, and the proportion of cells at G 1 phase increased significantly, suggesting that the cell cycle was blocked after IL-1ß treatment. After transfection with miR mimics, the expression level of miR-515-5p in the cells significantly up-regulated, partially reversing the apoptosis of OA chondrocytes induced by IL-1ß, and alleviating the cycle arrest and inflammatory response of OA chondrocytes. After treating C28/I2 cells with IL-1ß, the mRNA and protein levels of TLR4 significantly increased. Overexpression of miR-515-5p targeted inhibition of TLR4 expression and blocked activation of MyD88/nuclear factor κB (NF-κB) pathway. Overexpression of TLR4 could partially reverse the effect of miR mimics on IL-1ß-induced apoptosis and inflammation of OA chondrocytes. Conclusion: miR-515-5p negatively regulates the expression of TLR4, inhibits the activation of MyD88/NF-κB pathway and apoptosis of OA chondrocytes, and effectively alleviates the inflammatory response of the cells.

Taraxasterol enhanced bladder cancer cells radiosensitivity via inhibiting the COX-2/PGE2/JAK2/STAT3/MMP pathway.

PURPOSE: Radiotherapy with bladder preservation is highly acceptable among patients bearing bladder cancer (BCa), but the occurrence of secondary tolerance (ARR) during treatment is one of the important reasons for the failure of clinical radiotherapy. COX-2 has been frequently reported to be highly expressed and associated with radio-resistance in various cancers. In this study, the feasibility of Taraxasterol (Tara) as a radiosensitizer was investigated, and the target effect of Tara on COX-2 and its underlying mechanism were explored. METHODS AND MATERIALS: The toxicity of Tara toward BCa cells was detected with the MTT method and cells in response to IR or Tara + IR were compared by clone formation assay. Next, a small RNA interference system (siRNA) was employed to decrease endogenous COX-2 expression in BCa cells, and the stem cell-like features and motion abilities of BCa cells under different treatments were investigated using microsphere formation and transwell chamber assay, respectively. Meanwhile, the expression of a series of inflammation-related molecules and stem cell characteristic molecules was determined by qRT-PCR, western blot and ELISA method. In vivo studies, BCa cells were subcutaneously injected into the right flank of each male mouse. Those mice were then grouped and exposed to different treatment: Tara, IR, IR + Tara and untreated control. The volumes of each tumor were measured every two days and target proteins were detected with immunohistochemical (IHC) staining. RESULTS: The results show that COX-2 decline, due to COX-2 knocking-down or Tara treatment, could greatly enhance BCa cells' radiosensitivity and significantly decrease their migration, invasion and microsphere formation abilities, companied with the reduce of JAK2, phos-STAT3, MMP2 and MMP9 expression. However, Tara could not further reduce the expression of an above molecule of cells in COX-2-deficient BCa cells. Correspondingly, Tara treatment could not further enhance those siCOX-2 BCa cells response to IR. CONCLUSIONS: Our data support that Tara can improve the radiosensitivity of BCa cells by targeting COX-2/PGE2. The mechanism may involve regulating STAT3 phosphorylation, DNA damage response protein activation, and expression of MMP2/MMP9.