Enforced HCELL Expression Enhances Bone Marrow Stromal Cells Homing and Amelioration of Cerebral Ischemia-Reperfusion Injury via induction of PGE2.

Ischemic stroke (IS) is a significant and potentially life-threatening disease with limited treatment options, often resulting in severe disability. Bone marrow stromal cells (BMSCs) transplantation has exhibited promising neuroprotection following cerebral ischemia-reperfusion injury (CIRI). However, the effectiveness is hindered by their low homing rate when administered through the vein. In this study, we aimed to enhance the homing ability of BMSCs through lentivirus transfection to express fucosyltransferase 7. This glycosylation engineered CD44 on BMSCs to express hematopoietic cell E-selectin/L-selectin ligand (HCELL), which is the most potent E-selectin ligand. Following enforced HCELL expression, the transplantation of BMSCs was then evaluated in a middle cerebral artery occlusion (MCAO) model. Results showed that HCELL+BMSCs significantly ameliorated neurological deficits and reduced the volume of cerebral infarction. Furthermore, the transplantation led to a decrease in apoptosis by up-regulating BCL-2 and down-regulating BAX, also reduced the mRNA levels of inflammatory factors, such as interleukin-1ß (IL-1ß), IL-2, IL-6 and tumor necrosis factor-alpha (TNF-α) in the ischemic brain tissue. Notably, enforced HCELL expression facilitated the migration of BMSCs towards cerebral ischemic lesions and their subsequent transendothelial migration through the up-regulation of PTGS-2, increased production of PGE2 and activation of VLA-4. In summary, our study demonstrates that transplantation of HCELL+BMSCs effectively alleviates CIRI, and that enforced HCELL expression enhances the homing of BMSCs to cerebral ischemic lesions and their transendothelial migration via PTGS-2/PGE2/VLA-4. These findings indicate that enforced expression of HCELL on BMSCs could serve as a promising therapeutic strategy for the treatment of ischemic stroke.

Histopathological and biochemical evaluation of the protective efficacy of Prunus spinosa L. extract in a rat model of indomethacin-induced gastric ulcer.

Objectives: Some species of Prunus L. are popularly used to treat gastric ulcers. However, the possible healing mechanisms of the anti-ulcer activity of P. spinosa, which has proven antioxidant, anti-inflammatory, and wound-healing properties, are unclear. Materials and Methods: Ethanol extracts of P. spinosa fruits were administered orally at 100 mg/kg and 200 mg/kg to Wistar albino rats, with an indomethacin-induced gastric ulcer model. The ulcerous areas on the stomach surface were examined macroscopically. Tissues were examined histopathologically and biochemically. LC-HRMS revealed the phytochemical content. Results: TNF-α, IL-6, IL-1ß, IL-8, and NF-kB levels were higher in the gastric ulcer group than in the extract groups. The VEGF values did not differ in each group. A significant difference was found between the lansoprazole group and the high-dose P. spinosa group regarding PGE2 levels. A histopathologically significant difference was observed between the healthy group and the indomethacin-applied groups in terms of neutrophilic infiltration of the gastric mucosa. Ascorbic acid (1547.521 µg/g), homoprotocatechuic acid (1268.217 µg/g), and genistein (1014.462 µg/g) were found as the main compounds in the P. spinosa extract by LC-HRMS. Conclusion: Our results demonstrated that P. spinosa protected the gastric mucosa from inflammation and also modulated the PGE2 pathway. When considered in terms of TNF-α, IL-1ß, IL-8, IL-6, PGE2, and NF-kB values, it can be concluded that it has a similar or even more positive effect than the reference substance. P. spinosa showed its effects in a dose-dependent manner.

Pentacyclic triterpenes as bioactive compounds isolated from Mauritia flexuosa L. f. acting against the Alzheimer's disease.

Alzheimer's disease is a significant concern due to its high prevalence and the limitations of current treatments. In our research, we investigated Mauritia flexuosa, a medicinal plant traditionally used for headaches, to identify active compounds with potential anti-Alzheimer's effects. Three pentacyclic triterpenes were isolated through column chromatography and characterised from the dichloromethane/methanol extract from Mauritia flexuosa (DCMEMf), with (3ß)-3-hydroxy-11-oxours-12-en-28-oic acid (3) showing the highest in vitro activity in the HMC3 and SVG p12 cell lines. Compound 3 inhibited the pharmacological targets NF-κB, PGE2, IDO1, and EGFR with IC50 values of 9.83, 3.86, 1.63 µM, and 49.57 nM, respectively, attributed to a hydroxyl group at the C-3 position of its structure. These findings suggest the potential of these compounds in treating neurological diseases, including headaches, and offer promising prospects for the development of new therapies against Alzheimer's.

Myricetin-loaded SBA-15 silica nanoparticles for enhanced management of pyrexia, pain, and inflammation through modulation of MAPK/NF-κB and COX-2/PGE-2 pathways: Evidence from the biochemical, histological, and metabolomic analysis.

Myricetin (MYR) is a natural flavonoid that has several biological functions. However, some of its beneficial effects are diminished due to low water solubility, stability, and bioavailability. Herein, several kinds of silica nanoparticles (MCM-41 and SBA-15) were loaded with MYR to improve its biological activity as an analgesic, antipyretic, and anti-inflammatory component, thereby overcoming its drawbacks. The nanoparticles (MYR@SBA-15) were formulated optimally, transforming MYR into an amorphous state. This transformation was confirmed via several strategies, including differential scanning calorimetry, Fourier transform infrared spectroscopy, and powder x-ray diffraction. As a result, there was a significant enhancement in the solubility and rate of dissolution in water. The anti-inflammatory benefits as an innovative strategy and the underlying mechanism of action of MYR and its SBA-15 silica nanoparticles (MYR@SBA-15) were investigated based on the biochemical, histological, immunohistochemical, and metabolomic assays alongside their antipyretic and analgesic characteristics. Compared to the usage of raw MYR, the administration of MYR@SBA-15 at doses of 25, 50, and 100 mg/kg significantly decreases pain perception by inhibiting the body's writhing motions induced by acetic acid. Furthermore, it helps regulate increased body temperature caused by baking yeast and effectively stabilizes it. It reduces the release of NO and PGE-2 in a concentration-dependent manner by down-regulating iNOS and COX-2 expression in the inflammatory model. MYR and MYR@SBA-15 also inhibit the nuclear translocation of NF-κB, downregulate the expression of mitogen-activated protein kinases (MAPKs), such as p38, ERK1/2, and JNK protein, and reduce the generation of proinflammatory cytokines, such as TNF-α. In addition, inflammatory cardinal signs like paw edema caused by carrageenan in rats are greatly suppressed by MYR and MYR@SBA-15 treatment when compared to the untreated group. More noteworthy outcomes are shown in the MYR@SBA-15, particularly at a dose of 100 mg/kg. These results of biochemical and immuno-histochemistry suggest that MYR@SBA-15 may be a useful analgesic antipyretic and may also help reduce inflammation by altering MAPKs/NF-κB and COX-2/PGE-2 signaling cascades. Serum metabolomics study demonstrated modifications in various low molecular weight metabolites with arthritis development. These metabolite levels were restored to normal when MYR@SBA-15 was administered via modulating several metabolic pathways, i.e., pyrimidine, energy metabolism, and proteins. Overall, MYR-loaded SBA-15 silica nanoparticles have demonstrated significant promise in enhancing the disturbed metaboloic pathways and providing a substantial capacity to regulate several oxidative stress and inflammatory mediators.

PTGER4 signaling regulates class IIa HDAC function and SPINK4 mRNA levels in rectal epithelial cells.

BACKGROUND: The prostaglandin receptor PTGER4 facilitates homeostasis in the gut. Previous reports indicate that goblet cells, marked by SPINK4 expression, might be affected by PTGER4 activity. Current evidence suggests that prostaglandin E2 (PGE2) produced by mesenchymal stromal cells (MSC) stimulates PTGER4 in epithelial cells during inflammatory conditions. Here, we investigate the subcellular mechanisms and mRNA levels downstream of PTGER4 activity in epithelial cells. METHODS: Mucosal cells, organoids, and MSC were obtained from patient biopsies harvested by endoscopy. Using independent and co-cultures, we manipulated the activity of PTGER4, the downstream enzymes, and mRNA levels, by using PGE2, in combination with chemical inhibitors, L-161982, H89, LB100, DAPT, LMK-235, or with butyrate. Immunofluorescence, single cell sequencing, RNAscope, ELISA, real time PCR, and Western blotting were used to examine these samples. RESULTS: SPINK4 mRNA levels were increased in organoids by co-culture with MSC or exogenous stimulation with PGE2 that could be blocked by L-161982 or LMK-235, PTGER4 or HDAC4 inhibitors, respectively. Expression of PTGER4 was co-localized with JAM-A in the basolateral surfaces in rectal epithelial cells grown as organoids. PGE2 treatment of rectal organoids decreased HDAC4, 5, and 7 phosphorylation levels that could be blocked by L-161982 treatment. Butyrate treatment, or addition of L-161982, increased the phosphorylated levels of HDAC4, 5, and 7. CONCLUSIONS: These findings suggest a mechanism during mucosal injury whereby MSC production of PGE2 increases HDAC4, 5, and 7 activities in epithelial cells by upregulating PTGER4 signaling, ultimately increasing SPINK4 mRNA levels and extracellular release of SPINK4.

Efficacy of controlled-release dinoprostone vaginal insert for elective induction of labor before due date.

AIM: The induction of labor before due date has recently been proved to reduce the rate of cesarean sections and is not associated with increased risk of adverse perinatal outcomes as compared to expectant management. Controlled-release dinoprostone (PGE2) vaginal insert has recently been approved for use in Japan. However, evidence regarding its efficacy in cervical ripening and labor induction before due date remains limited. We aimed to compare the efficacy of PGE2 vaginal inserts and mechanical dilation for labor induction before due date. METHODS: This retrospective cohort study included 206 mothers at 37, 38, and 39 weeks' gestation delivered at our institution between January 2021 and October 2022. Perinatal outcomes, including the success rate of vaginal delivery, were compared between the PGE2 (n = 46) and metreurynter/laminaria tent (non-PGE2) (n = 160) groups. The success rate of vaginal delivery was defined as the proportion of women who delivered vaginally within 48 h of initiating oxytocin augmentation. RESULTS: The success rate of vaginal delivery was significantly higher in the PGE2 group (37/49, 80.4%) than in the non-PGE2 group (106/177, 66.2%). Emergency cesarean section related to non-reassuring fetal status was performed with none in the PGE2 group and with eight (5.0%) in the non-PGE2 group. CONCLUSIONS: The rate of vaginal delivery was significantly higher in the PGE2 group for elective labor induction between 37 and 39 weeks. The PGE2 vaginal insert could increase the success rate of vaginal delivery for elective induction of labor at 39 weeks.

Effects of radial extracorporeal shock wave with different frequencies on acute skeletal muscle injury in rabbits.

To study the efficacy and possible mechanisms of radial extracorporeal shock wave (rESW) with different frequencies for the treatment of acute skeletal muscle injury in rabbits, 48 rabbits of acute injured biceps femoris were randomly divided into 4 groups. Except for the control group, the other groups were treated by rESW with 5 Hz, 10 Hz and 15 Hz, respectively. The injury symptom index scores (ISISs) in the rESW group were significantly lower than those in the control group, with the lowest in the 10 Hz rESW group. Histomorphological features demonstrated a decrease in mononuclear cells and an increase in new myocytes across all groups, with the rESW group showing the most significant changes. The concentrations of PGE2 and IL-1ß were significantly lower in all rESW groups by ELISA compared to the control group. Additionally, the 10 Hz group had lower concentrations than the 5 Hz and 15 Hz group. Compared with the control group, MyoD of the rESW groups was significantly increased, and the expression level of the 10 Hz group was higher than that of the other groups. In conclusion, rESW with 5 Hz, 10 Hz and 15 Hz take certain curative effects on acute biceps femoris injury in rabbits, and the 10 Hz rESW takes advantage over 5 Hz and 15 Hz rESW.

Tumor ABCC4-mediated release of PGE2 induces CD8+ T cell dysfunction and impairs PD-1 blockade in prostate cancer.

Prostate cancer presents as an immunologically "cold" malignancy, characterized by a lack of response to immunotherapy in the majority of patients. The dysfunction of prostate tumor metabolism is recognized as a critical factor in immune evasion, resulting in reduced effectiveness of immunotherapeutic interventions. Despite this awareness, the precise molecular mechanisms underpinning metabolic dysregulation in prostate cancer and its intricate relationship with immune evasion remain incompletely elucidated. In this study, we introduce the multi-drug resistance protein ABCC4/MRP4 as a key player prominently expressed in prostate cancer, exerting a pivotal role in suppressing the activity of intratumoral CD8+ T cells. Depletion of ABCC4 in prostate cancer cells halts the release of prostaglandin E2 (PGE2), a molecule that diminishes the population of CD8+ T cells and curtails their cytotoxic capabilities. Conversely, constraining the activation of PGE2 signaling in CD8+ T cells effectively improved the efficacy of prostate cancer treatment with PD-1 blockade. During this process, downregulation of the JAK1-STAT3 pathway and depolarization of mitochondria emerge as crucial factors contributing to T cell anergy. Collectively, our research identifies the ABCC4-PGE2 axis as a promising target for reversing dysfunction within tumor-infiltrating lymphocytes (TILs) and augmenting the suboptimal responsiveness to immunotherapy in prostate cancer.

A New Frontier in Cystic Fibrosis Pathophysiology: How and When Clock Genes Can Affect the Inflammatory/Immune Response in a Genetic Disease Model.

Cystic fibrosis (CF) is a monogenic syndrome caused by variants in the CF Transmembrane Conductance Regulator (CFTR) gene, affecting various organ and systems, in particular the lung, pancreas, sweat glands, liver, gastrointestinal tract, vas deferens, and vascular system. While for some organs, e.g., the pancreas, a strict genotype-phenotype occurs, others, such as the lung, display a different pathophysiologic outcome in the presence of the same mutational asset, arguing for genetic and environmental modifiers influencing severity and clinical trajectory. CFTR variants trigger a pathophysiological cascade of events responsible for chronic inflammatory responses, many aspects of which, especially related to immunity, are not ascertained yet. Although clock genes expression and function are known modulators of the innate and adaptive immunity, their involvement in CF has been only observed in relation to sleep abnormalities. The aim of this review is to present current evidence on the clock genes role in immune-inflammatory responses at the lung level. While information on this topic is known in other chronic airway diseases (chronic obstructive pulmonary disease and asthma), CF lung disease (CFLD) is lacking in this knowledge. We will present the bidirectional effect between clock genes and inflammatory factors that could possibly be implicated in the CFLD. It must be stressed that besides sleep disturbance and its mechanisms, there are not studies directly addressing the exact nature of clock genes' involvement in inflammation and immunity in CF, pointing out the directions of new and deepened studies in this monogenic affection. Importantly, clock genes have been found to be druggable by means of genetic tools or pharmacological agents, and this could have therapeutic implications in CFLD.

Anti-Inflammatory Effects of the Combined Treatment of Resveratrol- and Protopanaxadiol-Enriched Rice Seed Extract on Lipopolysaccharide-Stimulated RAW264.7 Cells.

The overproduction of proinflammatory cytokines triggers a variety of diseases. Protopanaxadiol (PPD) and resveratrol are naturally found in plants such as ginseng and have potential anti-inflammatory properties, and resveratrol- and PPD-enriched rice seeds have been previously successfully generated. Herein, the synergistic anti-inflammatory activities of extracts of these enriched seeds were assessed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In comparison with treatment using extract prepared from PPD-producing transgenic rice (DJ-PPD) alone, cotreatment with DJ526 and DJ-PPD (TR_3) markedly enhanced the anti-inflammatory activities at a similar (compared to DJ526) or higher (compared to DJ-PPD) level. Cotreatment with DJ526 and DJ-PPD markedly inhibited the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Thus, DJ526 and DJ-PPD in combination suppressed the expression of phosphorylated (p)-NF-κB p65, p-p38 MAPK, and p-ERK 1/2. Cotreatment with DJ526 and DJ-PPD downregulated the expression of proinflammatory cytokines (IL-1ß, IL-6, and TNF-α), LPS receptor (toll-like receptor-4, TLR-4), proinflammatory mediators (nitric oxide and PGE2), and arachidonic acid pathway critical enzyme (COX-2). These findings demonstrate the synergistic potential anti-inflammatory activities of resveratrol- and PPD-enriched rice seed extract.

Indoxyl sulfate induces retinal microvascular injury via COX-2/PGE2 activation in diabetic retinopathy.

BACKGROUND: Diabetic retinopathy (DR), the principal cause of acquired blindness among the working-age population, is the most frequent microvascular complication of diabetes. Although metabolic disorders are hypothesized to play a role in its pathogenesis, the underlying mechanism remains largely elusive. METHODS: To elucidate the mechanism, we initially compared metabolite profiles of vitreous fluid between 23 patients with DR and 12 non-diabetic controls using liquid chromatography/tandem mass spectrometry, identifying the distinct metabolite indoxyl sulfate (IS). Subsequently, streptozotocin (STZ)-induced diabetic and IS-injected rat models were established to examine the effects of IS on retinal microvasculature. RNA sequencing was conducted to identify potential regulatory mechanisms in IS-treated human retinal endothelial cells (HREC). Finally, target gene knockdown in HREC and treatment of IS-injected rats with inhibitors (targeting IS production or downstream regulators) were employed to elucidate the detailed mechanisms and identify therapeutic targets for DR. RESULTS: Metabolomics identified 172 significantly altered metabolites in the vitreous humor of diabetics, including the dysregulated tryptophan metabolite indoxyl sulfate (IS). IS was observed to breach the blood-retinal barrier and accumulate in the intraocular fluid of diabetic rats. Both in vivo and in vitro experiments indicated that elevated levels of IS induced endothelial apoptosis and disrupted cell junctions. RNA sequencing pinpointed prostaglandin E2 (PGE2) synthetase-cyclooxygenase 2 (COX-2) as a potential target of IS. Validation experiments demonstrated that IS enhanced COX-2 expression, which subsequently increased PGE2 secretion by promoting transcription factor EGR1 binding to COX-2 DNA following entry into cells via organic anion transporting polypeptides (OATP2B1). Furthermore, inhibition of COX-2 in vivo or silencing EGR1/OATP2B1 in HREC mitigated IS-induced microcapillary damage and the activation of COX-2/PGE2. CONCLUSION: Our study demonstrated that indoxyl sulfate (IS), a uremic toxin originating from the gut microbiota product indole, increased significantly and contributed to retinal microvascular damage in diabetic retinopathy (DR). Mechanistically, IS impaired retinal microvascular integrity by inducing the expression of COX-2 and the production of PGE2. Consequently, targeting the gut microbiota or the PGE2 pathway may offer effective therapeutic strategies for the treatment of DR.

Leishmania infantum exploits the anti-ferroptosis effects of Nrf2 to escape cell death in macrophages.

Macrophages are major host cells for the protozoan Leishmania parasite. Depending on their activation state, they either contribute to the detection and elimination of Leishmania spp. or promote parasite resilience. Here, we report that the activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in macrophages plays a pivotal role in the progression of Leishmania infantum infection by controlling inflammation and redox balance of macrophages. We also highlight the involvement of the NOX2/reactive oxygen species (ROS) axis in early Nrf2 activation and, subsequently, prostaglandin E2 (PGE2)/EP2r signaling in the sustenance of Nrf2 activation upon infection. Moreover, we establish a ferroptosis-like process within macrophages as a cell death program of L. infantum and the protective effect of Nrf2 in macrophages against L. infantum death. Altogether, these results identify Nrf2 as a critical factor for the susceptibility of L. infantum infection, highlighting Nrf2 as a promising pharmacological target for the development of therapeutic approaches for the treatment of visceral leishmaniasis.

Tryptophan regulates the expression of IGFBP1 in bovine endometrial epithelial cells in vitro via the TDO2-AHR pathway.

BACKGROUND: This study aimed to identify the roles of L-tryptophan (Trp) and its rate-limiting enzymes on the receptivity of bovine endometrial epithelial cells. Real-time PCR was conducted to analyze the differential expression of genes between different groups of bovine endometrial epithelial cells. Western blot was performed to detect Cyclooxygenase-2 (COX2) expression after treatment with Trp or kynurenine (the main metabolites of Trp). The kynurenine assay was used to examine if Trp or prostaglandin E2 (PGE2) can increase the production of kynurenine in the bovine endometrial epithelial cells. RESULTS: Trp significantly stimulates insulin growth factor binding protein 1 (IGFBP1) expression, a common endometrial marker of conceptus elongation and uterus receptivity for ruminants. When bovine endometrial epithelial cells are treated with Trp, tryptophan hydroxylase-1 remains unchanged, but tryptophan 2,3-dioxygenase 2 (TDO2) is significantly increased, suggesting tryptophan is mainly metabolized through the kynurenine pathway. Kynurenine significantly stimulates IGFBP1 expression. Furthermore, Trp and kynurenine significantly increase the expression of aryl hydrocarbon receptor (AHR). CH223191, an AHR inhibitor, abrogates the induction of Trp and kynurenine on IGFBP1. PGE2 significantly induces the expression of TDO2, AHR, and IGFBP1. CONCLUSIONS: The regulation between Trp / kynurenine and PGE2 may be crucial for the receptivity of the bovine uterus.

EP4 receptor agonist CAY10598 upregulates ROS-dependent Hsp90 cleavage in colorectal cancer cells.

Prostaglandin E2 (PGE2) interacts with four specific G protein-coupled receptors, namely EP1, EP2, EP3, and EP4, playing a pivotal role in determining the fate of cells. Our previous findings highlighted that stimulating the EP4 receptor with its agonist, CAY10598, triggers apoptosis in colon cancer HCT116 cells via the production of reactive oxygen species (ROS). This process also reduces the phosphorylation of the oncogenic protein JAK2 and leads to its degradation in these cells. In this study, our goal was to explore the pathways through which CAY10598 leads to JAK2 degradation. We focused on Hsp90, a heat shock protein family member known for its role as a molecular chaperone maintaining the stability of several key proteins including EGFR, MET, Akt, and JAK2. Our results show that CAY10598 decreases the levels of client proteins of Hsp90 in HCT116 cells, an effect reversible by pretreatment with the ROS scavenger N-acetyl cysteine (NAC) or the proteasome inhibitor MG132, indicating that the degradation is likely driven by ROS. Furthermore, we observed that CAY10598 cleaves both α and ß isoforms of Hsp90, the process inhibited by NAC. Inhibition of EP4 with the antagonist GW627368x not only prevented the degradation of Hsp90 client proteins but also the cleavage of Hsp90 itself in CAY10598-treated HCT116 cells. Additionally, CAY10598 suppressed the growth of HCT116 cells implanted in mice. Our findings reveal that CAY10598 induces apoptosis in cancer cells by a novel mechanism involving the ROS-dependent cleavage of Hsp90, thereby inhibiting the function of crucial Hsp90 client proteins.

iNOS/PGE2 inhibitors as a novel template for analgesic/anti-inflammatory activity: Design, synthesis, in vitro biological activity and docking studies.

Due to the serious gastrointestinal side effects associated with prolonged use of current anti-inflammatory therapies, various strategies such as the regulation of nitric oxide (NO) and prostaglandin E2 (PGE2) production have been explored in the field of anti-inflammatory drug development. In this study, a series of disubstituted 1,3,4-oxadiazoles (3a-f and 4a-f) and their cyclized 1,2,4-triazole derivatives (5a-e and 6a-e) were synthesized and tested for their NO, PGE2, and interleukin-6 (IL-6) releasing inhibition ability. All of the compounds were observed to reduce lipopolysaccharide (LPS)-induced nitrite production in a concentration-dependent manner. Moreover, compounds 3b (50 µM) and 6d (1 µM) exhibited 63% and 49% inhibition, respectively, while indomethacin showed 52% at 100 µM. Based on a preliminary NO inhibition assay, 10 of the compounds (3a, 3b, 3e, 4b, 4d, 6a-e) were selected to be evaluated for in vitro PGE2, IL-6, and inducible nitric oxide synthase (iNOS) inhibition. Notably, compound 6d proved to be the most active of the series with the lowest dose (1 µM), in comparison to the other further tested compounds (5-100 µM) and the reference drug indomethacin (100 µM). The inhibitory activity of the compounds was supported by docking simulations into the binding site of the iNOS protein receptor (Protein Data Bank [PDB]ID: 3E7G). The data showing that 4d reduced iNOS levels the most can be explained by the H-bond with Tyr347 through oxadiazole and π-halogen interactions through the p-bromo, in addition to aromatic interactions with protoporphyrin IX.

Transcriptional Regulation and Function of Malic Enzyme 1 in Human Macrophage Activation.

Macrophages represent primary players of the innate immune system. Macrophage activation triggers several signaling pathways and is tightly associated with metabolic changes, which drive different immune subsets. Recent studies unveil the role of various metabolic enzymes in macrophage activation. Here, we show that malic enzyme 1 (ME1) is overexpressed in LPS-induced macrophages. Through chromatin immunoprecipitation, we demonstrate that ME1 transcriptional regulation is under control of NF-κB. Furthermore, ME1 activity is also increased in activated human PBMC-derived macrophages. Notably, ME1 gene silencing decreases nitric oxide as well as reactive oxygen species and prostaglandin E2 inflammatory mediators. Therefore, modulating ME1 provides a potential approach for immunometabolic regulation and in turn macrophage function.

Myeloid Cells and Sensory Nerves Mediate Peritendinous Adhesion Formation via Prostaglandin E2.

Peritendinous adhesion that forms after tendon injury substantially limits daily life. The pathology of adhesion involves inflammation and the associated proliferation. However, the current studies on this condition are lacking, previous studies reveal that cyclooxygenase-2 (COX2) gene inhibitors have anti-adhesion effects through reducing prostaglandin E2 (PGE2) and the proliferation of fibroblasts, are contrary to the failure in anti-adhesion through deletion of EP4 (prostaglandin E receptor 4) gene in fibroblasts in mice of another study. In this study, single-cell RNA sequencing analysis of human and mouse specimens are combined with eight types of conditional knockout mice and further reveal that deletion of COX2 in myeloid cells and deletion of EP4 gene in sensory nerves decrease adhesion and impair the biomechanical properties of repaired tendons. Furthermore, the COX2 inhibitor parecoxib reduces PGE2 but impairs the biomechanical properties of repaired tendons. Interestingly, PGE2 local treatment improves the biomechanical properties of the repaired tendons. These findings clarify the complex role of PGE2 in peritendinous adhesion formation (PAF) and tendon repair.

ERK5 mediates pro-tumorigenic phenotype in non-small lung cancer cells induced by PGE2.

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.

Homocysteine Promotes Intestinal Inflammation in Colitis Mice Through the PGE2/STAT3 Signaling Pathway.

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. CONCLUSION: HHcy aggravated DSS-induced colitis by promoting the differentiation and proliferation of Th17 cells through the PGE2 / STAT3 signaling pathway.

COX-2 optimizes cardiac mitochondrial biogenesis and exerts a cardioprotective effect during sepsis.

BACKGROUND: Septic cardiomyopathy is a component of multiple organ dysfunction in sepsis. Mitochondrial dysfunction plays an important role in septic cardiomyopathy. Studies have shown that cyclooxygenase-2 (COX-2) had a protective effect on the heart, and prostaglandin E2 (PGE2), the downstream product of COX-2, was increasingly recognized to have a protective effect on mitochondrial function. OBJECTIVE: This study aims to demonstrate that COX-2/PGE2 can protect against septic cardiomyopathy by regulating mitochondrial function. METHODS: Cecal ligation and puncture (CLP) was used to establish a mouse model of sepsis and RAW264.7 macrophages and H9C2 cells were used to simulate sepsis in vitro. The NS-398 and celecoxib were used to inhibit the activity of COX-2. ZLN005 and SR18292 were used to activate or inhibit the PGC-1α activity. The mitochondrial biogenesis was examined through the Mitotracker Red probe, mtDNA copy number, and ATP content detection. RESULTS: The experimental data suggested that COX-2 inhibition attenuated PGC-1α expression thus decreasing mitochondrial biogenesis, whereas increased PGE2 could promote mitochondrial biogenesis by activating PGC-1α. The results also showed that the effect of COX-2/PGE2 on PGC-1α was mediated by the activation of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB). Finally, the effect of COX-2/PGE2 on the heart was also verified in the septic mice. CONCLUSION: Collectively, these results suggested that COX-2/PGE2 pathway played a cardioprotective role in septic cardiomyopathy through improving mitochondrial biogenesis, which has changed the previous understanding that COX-2/PGE2 only acted as an inflammatory factor.