Associations of E-proteinoid 3 receptor genetic polymorphisms with salt sensitivity, longitudinal blood pressure changes, and hypertension incidence in Chinese adults.

The E-proteinoid 3 receptor (PTGER3), a member of the prostaglandin E2 (PGE2) subtype receptor, belongs to the G-protein-coupled superfamily of receptors. Animal studies have demonstrated its involvement in salt sensitivity by regulating sodium reabsorption. This study aimed to investigate the association between genetic variants of PTGER3 and salt sensitivity, longitudinal blood pressure (BP) changes, and the incidence of hypertension in Chinese adults. A chronic salt intake intervention was conducted involving 514 adults from 124 families in the 2004 Baoji Salt-Sensitivity Study Cohort in northern China. These participants followed a 3-day regular baseline diet, followed by a 7-day low-salt diet (3.0 g/d) and a 7-day high-salt diet (18 g/d), and were subsequently followed for 14 years. The findings revealed a significant relationship between the single nucleotide polymorphism (SNP) rs17482751 of PTGER3 and diastolic blood pressure (DBP) response to high salt intervention. Additionally, SNPs rs11209733, rs3765894, and rs2268062 were significantly associated with longitudinal changes in systolic blood pressure (SBP), DBP, and mean arterial pressure (MAP) during the 14-year follow-up period. SNP rs6424414 was significantly associated with longitudinal changes in DBP over 14 years. Finally, SNP rs17482751 showed a significant correlation with the incidence of hypertension over 14 years. These results emphasize the significant role of PTGER3 gene polymorphism in salt sensitivity, longitudinal BP changes, and the development of hypertension in the Chinese population.

PTGER3 knockdown inhibits the vulnerability of triple-negative breast cancer to ferroptosis.

Prostaglandin E receptor 3 (PTGER3) is involved in a variety of biological processes in the human body and is closely associated with the development and progression of a variety of cancer types. However, the role of PTGER3 in triple-negative breast cancer (TNBC) remains unclear. In the present study, low PTGER3 expression was found to be associated with poor prognosis in TNBC patients. PTGER3 plays a crucial role in regulating TNBC cell invasion, migration, and proliferation. Upregulation of PTGER3 weakens the epithelial-mesenchymal phenotype in TNBC and promotes ferroptosis both in vitro and in vivo by repressing glutathione peroxidase 4 (GPX4) expression. On the other hand, downregulation of PTGER3 inhibits ferroptosis by increasing GPX4 expression and activating the PI3K-AKT pathway. Upregulation of PTGER3 also enhances the sensitivity of TNBC cells to paclitaxel. Overall, this study has elucidated critical pathways in which low PTGER3 expression protects TNBC cells from undergoing ferroptosis, thereby promoting its progression. PTGER3 may thus serve as a novel and promising biomarker and therapeutic target for TNBC.

Correlation of Reduced PTGER3 Expression with Prognosis and Immune Infiltration in Clear Cell Renal Carcinoma.

BACKGROUND: Prostaglandin E2 receptor 3 (PTGER3, EP3) is essential for many malignancies growth and metastasis. The role of PTGER3 in kidney renal clear cell carcinoma (KIRC) was assessed in terms of its prognosis and its association with immune infiltration. METHODS: Transcriptomic expression profiles of PTGER3 were acquired from The Cancer Genome Atlas (TCGA) database. Comparative analysis was performed to evaluate the disparity in PTGER3 expression between KIRC and normal tissues. The discriminative potential of PTGER3 as a distinguishing determinant was assessed through receiver operating characteristic (ROC) curves. Prognostic factors were evaluated employing COX regression and logistic models. Furthermore, the impact of PTGER3 on survival was ascertained utilizing the Kaplan-Meier method. A protein-protein interaction (PPI) network was constructed utilizing the STRING database. To investigate the correlation between immune infiltration levels and PTGER3 expression, a single-sample Gene Set Enrichment Analysis (GSEA) method was employed, employing the Gene Set Variation Analysis (GSVA) package and the Tumor Immune Estimation Resource (TIMER) database. RESULTS: Bioinformatics analysis unveiled a significant downregulation of PTGER3 expression in KIRC tissues compared to paraneoplastic tissues (p < 0.001). Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) experiments demonstrated a reduction in PTGER3 expression in 786-O cells in contrast to paraneoplastic tissues (p < 0.01). The ROC curve, employing PTGER3 as a potential diagnostic biomarker, exhibited a substantial area under the curve (AUC) value of 0.929. According to the Kaplan-Meier survival analysis, reduced PTGER3 expression increased the chance of negative overall survival (OS) (p = 0.019). A PPI network was constructed, elucidating the interaction patterns between PTGER3 and the top 10 co-expressed genes. An examination of gene enrichment and immune infiltration levels found a link between PTGER3 transcription and immune infiltration levels. Notably, high B cell counts and low Mast cell counts were connected to a poor prognosis in KIRC patients. CONCLUSIONS: The expression of PTGER3 was found to be diminished in KIRC in comparison to paracancerous tissue. This observation exhibited a correlation with both prognosis and immune cell infiltration. As a result, our findings suggest that PTGER3 could be considered a promising biomarker to forecast KIRC prognosis and as a possible target for immunotherapy.

Correlation of Reduced PTGER3 Expression with Prognosis and Immune Infiltration in Clear Cell Renal Carcinoma

Background: Prostaglandin E2 receptor 3 (PTGER3, EP3) is essential for many malignancies growth and metastasis. The role of PTGER3 in kidney renal clear cell carcinoma (KIRC) was assessed in terms of its prognosis and its association with immune infiltration. Methods: Transcriptomic expression profiles of PTGER3 were acquired from The Cancer Genome Atlas (TCGA) database. Comparative analysis was performed to evaluate the disparity in PTGER3 expression between KIRC and normal tissues. The discriminative potential of PTGER3 as a distinguishing determinant was assessed through receiver operating characteristic (ROC) curves. Prognostic factors were evaluated employing COX regression and logistic models. Furthermore, the impact of PTGER3 on survival was ascertained utilizing the Kaplan–Meier method. A protein-protein interaction (PPI) network was constructed utilizing the STRING database. To investigate the correlation between immune infiltration levels and PTGER3 expression, a single-sample Gene Set Enrichment Analysis (GSEA) method was employed, employing the Gene Set Variation Analysis (GSVA) package and the Tumor Immune Estimation Resource (TIMER) database. Results: Bioinformatics analysis unveiled a significant downregulation of PTGER3 expression in KIRC tissues compared to paraneoplastic tissues (p < 0.001). Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) experiments demonstrated a reduction in PTGER3 expression in 786-O cells in contrast to paraneoplastic tissues (p < 0.01). The ROC curve, employing PTGER3 as a potential diagnostic biomarker, exhibited a substantial area under the curve (AUC) value of 0.929. According to the Kaplan–Meier survival analysis, reduced PTGER3 expression increased the chance of negative overall survival (OS) (p = 0.019). A PPI network was constructed, elucidating the interaction patterns between PTGER3 and the top 10 co-expressed genes (AU)

Posttranscriptional regulation of the prostaglandin E receptor spliced-isoform EP3-γ and its implication in pancreatic ß-cell failure.

In Type 2 diabetes (T2D), elevated lipid levels have been suggested to contribute to insulin resistance and ß-cell dysfunction. We previously reported that the expression of the PGE2 receptor EP3 is elevated in islets of T2D individuals and is preferentially stimulated by palmitate, leading to ß-cell failure. The mouse EP3 receptor generates three isoforms by alternative splicing which differ in their C-terminal domain and are referred to as mEP3α, mEP3ß, and mEP3γ. We bring evidence that the expression of the mEP3γ isoform is elevated in islets of diabetic db/db mice and is selectively upregulated by palmitate. Specific knockdown of the mEP3γ isoform restores the expression of ß-cell-specific genes and rescues MIN6 cells from palmitate-induced dysfunction and apoptosis. This study indicates that palmitate stimulates the expression of the mEP3γ by a posttranscriptional mechanism, compared to the other spliced isoforms, and that the de novo synthesized ceramide plays an important role in FFA-induced mEP3γ expression in ß-cells. Moreover, induced levels of mEP3γ mRNA by palmitate or ceramide depend on p38 MAPK activation. Our findings suggest that mEP3γ gene expression is regulated at the posttranscriptional level and defines the EP3 signaling axis as an important pathway mediating ß-cell-impaired function and demise.

Susceptibility Genes and HLA for Cold Medicine-Related SJS/TEN with SOC.

We investigated the genetic predisposition for the pathogenesis of Stevens-Johnson syndrome/epidermal necrolysis with severe ocular complications (SJS/TEN with SOC). Cold medicines (CMs) including multi-ingredient cold-medications and non-steroidal anti-inflammatory drugs (NSAIDs) were implicated in the development of SJS/TEN with SOC. Studies on the association between HLA genotypes and CM-related SJS/TEN with SOC (CM-SJS/TEN with SOC) revealed an association with HLA-A*02:06 in the Japanese; it may be a marker in Koreans. HLA-B*44:03 was associated with the Japanese, Thais, and Indians; in Brazilians of European ancestry, it may be a positive marker. PTGER3 is a susceptibility gene; HLA-A*02:06 and PTGER3 polymorphisms exerted additive effects in Japanese and Korean patients. A genome-wide association study showed that IKZF1 was associated with the Japanese. A meta-analysis including Japanese, Koreans, Indians, and Brazilians also revealed an association between CM-SJS/TEN with SOC and IKZF1. The upregulation of hsa-miR-628-3p in the plasma of SJS/TEN with SOC patients may suppress the expression of TLR3 and innate immune-related genes. Not only CMs but also the interaction of TLR3, PTGER3, IKZF1, and HLA and maybe some microbial infections are necessary for the onset of SJS/TEN with SOC.

QPLOT Neurons-Converging on a Thermoregulatory Preoptic Neuronal Population.

The preoptic area of the hypothalamus is a homeostatic control center. The heterogeneous neurons in this nucleus function to regulate the sleep/wake cycle, reproduction, thirst and hydration, as well as thermogenesis and other metabolic responses. Several recent studies have analyzed preoptic neuronal populations and demonstrated neuronal subtype-specific roles in suppression of thermogenesis. These studies showed similar thermogenesis responses to chemogenetic modulation, and similar synaptic tracing patterns for neurons that were responsive to cold, to inflammatory stimuli, and to violet light. A reanalysis of single-cell/nucleus RNA-sequencing datasets of the preoptic nucleus indicate that these studies have converged on a common neuronal population that when activated, are sufficient to suppress thermogenesis. Expanding on a previous name for these neurons (Q neurons, which reflect their ability to promote quiescence and expression of Qrfp), we propose a new name: QPLOT neurons, to reflect numerous molecular markers of this population and to capture its broader roles in metabolic regulation. Here, we summarize previous findings on this population and present a unified description of QPLOT neurons, the excitatory preoptic neuronal population that integrate a variety of thermal, metabolic, hormonal and environmental stimuli in order to regulate metabolism and thermogenesis.

The effect of the EP3 antagonist DG-041 on male mice with diet-induced obesity.

BACKGROUND/AIMS: The prostaglandin E2 (PGE2) EP3 receptor has a multifaceted role in metabolism. Drugs targeting EP3 have been proposed as therapeutics for diabetes; however, studies utilizing global EP3 knockout mice suggest that EP3 blockade increases obesity and insulin resistance. The present studies attempt to determine the effect of acute EP3 antagonist treatment on the diabetic phenotype. METHODS: DG-041 was confirmed to be a high affinity antagonist at the mouse EP3 receptor by competition radioligand binding and by blockade of EP3-mediated responses. DG-041 pharmacokinetic studies were performed to determine the most efficacious route of administration. Male C57BL/6 × BALB/c (CB6F1) mice were fed diets containing 10%, 45%, or 60% calories from fat to induce obesity. Changes to the metabolic phenotype in these mice were evaluated after one week treatment with DG-041. RESULTS: Subcutaneous injections of DG-041 at 20 mg/kg blocked the sulprostone-evoked rise in mean arterial pressure confirming the efficacy of this administration regime. Seven day treatment with DG-041 had minimal effect on body composition or glycemic control. DG-041 administration caused a reduction in skeletal muscle triglyceride content while showing a trend toward increased hepatic triglycerides. CONCLUSION: Short term EP3 administration of DG-041 produced effective blockade of the EP3 receptor and decreased skeletal muscle triglyceride content but had no significant effects on the diabetic phenotype.

PTGER3 induces ovary tumorigenesis and confers resistance to cisplatin therapy through up-regulation Ras-MAPK/Erk-ETS1-ELK1/CFTR1 axis.

BACKGROUND: Inflammatory mediator prostaglandin E2-prostaglandin E2 receptor EP3 (PTGER3) signaling is critical for tumor-associated angiogenesis, tumor growth, and chemoresistance. However, the mechanism underlying these effects in ovarian cancer is not known. METHODS: An association between higher tumoral expression of PTGER3 and shorter patient survival in the ovarian cancer dataset of The Cancer Genome Atlas prompted investigation of the antitumor effects of PTGER3 downmodulation. PTGER3 mRNA and protein levels were higher in cisplatin-resistant ovarian cancer cells than in their cisplatin-sensitive counterparts. FINDINGS: Silencing of PTGER3 via siRNA in cancer cells was associated with decreased cell growth and less invasiveness, as well as cell-cycle arrest and increased apoptosis, mediated through the Ras-MAPK/Erk-ETS1-ELK1/CFTR1 axis. Furthermore, sustained PTGER3 silencing with multistage vector and liposomal 2'-F-phosphorodithioate-siRNA-mediated silencing of PTGER3 combined with cisplatin resulted in robust antitumor effects in cisplatin-resistant ovarian cancer models. INTERPRETATION: These findings identify PTGER3 as a potential therapeutic target in chemoresistant ovarian cancers expressing high levels of this oncogenic protein. FUND: National Institutes of Health/National Cancer Institute, USA.