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PloS One 2023To explore the metabolomics of fatty acids and biological information of related markers in a RAW264.7 cell inflammation model. RAW264.7 macrophage inflammation model...
GC-MS analysis of fatty acid metabolomics in RAW264.7 cell inflammatory model intervened by non-steroidal anti-inflammatory drugs and a preliminary study on the anti-inflammatory effects of NLRP3 signaling pathway.
To explore the metabolomics of fatty acids and biological information of related markers in a RAW264.7 cell inflammation model. RAW264.7 macrophage inflammation model was induced by LPS, and RAW264.7 cells were treated with non-steroidal anti-inflammatory drugs (NSAIDs). The fatty acid compositions were identified by GC-MS, combined with standard product spectrum information and NIST (National Institute of Standards and Technology) database. Using chemometrics and Analysis of Variance (ANOVA), the components with VIP > 1 and P < 0.05 were selected as significant difference markers, and combined with biological methods to explore the biological significance of them. GC-MS identified 21 fatty acids in RAW264.7 cells, and screened significant difference biomarkers in each group. Among these biomarkers, C20:5 and C22:6 had significant changes in pairwise comparison among each group. Through ELISA, polymerase chain reaction (PCR) and Western Blot methods, the mRNA and protein expressions of IL-1β, NLRP3, GPR120 and β-Arrestin-2 were up-regulated after RAW264.7 cells induced by LPS and nigericin, and decreased after drug intervention. It indicated that the signal pathway centered on NLRP3 inflammasome was involved in the anti-inflammatory process of ibuprofen. It was the first time to study fatty acid metabolomics in RAW264.7 cell inflammatory model by GC-MS combined with chemometrics. The anti-inflammatory mechanism of ibuprofen was explained from NLRP3 inflammasome perspective without precedent, which enriched the research on the signal pathway of ibuprofen anti-inflammatory mechanism.
Topics: Animals; Mice; Anti-Inflammatory Agents, Non-Steroidal; Fatty Acids; Gas Chromatography-Mass Spectrometry; Ibuprofen; Inflammasomes; Inflammation; Lipopolysaccharides; NLR Family, Pyrin Domain-Containing 3 Protein; RAW 264.7 Cells; Signal Transduction; Metabolome
PubMed: 37582087
DOI: 10.1371/journal.pone.0290051 -
Biochemical Pharmacology Jun 2024Arrestins are key negative regulators of G Protein-Coupled Receptors (GPCRs) through mediation of G protein desensitisation and receptor internalisation. Arrestins can...
Arrestins are key negative regulators of G Protein-Coupled Receptors (GPCRs) through mediation of G protein desensitisation and receptor internalisation. Arrestins can also contribute to signal transduction by scaffolding downstream signalling effectors for activation. GPCR kinase (GRK) enzymes phosphorylate the intracellular C-terminal domain, or intracellular loop regions of GPCRs to promote arrestin interaction. There are seven different GRK subtypes, which may uniquely phosphorylate the C-terminal tail in a type of 'phosphorylation barcode,' potentially differentially contributing to arrestin translocation and arrestin-dependent signalling. Such contributions may be exploited to develop arrestin-biased ligands. Here, we examine the effect of different GRK subtypes on the ability to promote translocation of arrestin-2 and arrestin-3 to the cannabinoid CB receptor (CB) with a range of ligands. We find that most GRK subtypes (including visual GRK1) can enhance arrestin-2 and -3 translocation to CB, and that GRK-dependent changes in arrestin-2 and arrestin-3 translocation were broadly shared for most agonists tested. GRK2/3 generally enhanced arrestin translocation more than the other GRK subtypes, with some small differences between ligands. We also explore the interplay between G protein activity and GRK2/3-dependent arrestin translocation, highlighting that high-efficacy G protein agonists will cause GRK2/3 dependent arrestin translocation. This study supports the hypothesis that arrestin-biased ligands for CB must engage GRK5/6 rather than GRK2/3, and G protein-biased ligands must have inherently low efficacy.
Topics: Humans; Receptor, Cannabinoid, CB1; Signal Transduction; HEK293 Cells; Arrestins; Protein Transport; GTP-Binding Proteins; G-Protein-Coupled Receptor Kinases; Animals; beta-Arrestin 2
PubMed: 38604257
DOI: 10.1016/j.bcp.2024.116190 -
Molecular Metabolism Aug 2023Cancer cells convert more glucose into lactate than healthy cells, what contributes to their growth advantage. Pyruvate kinase (PK) is a key rate limiting enzyme in this...
OBJECTIVE
Cancer cells convert more glucose into lactate than healthy cells, what contributes to their growth advantage. Pyruvate kinase (PK) is a key rate limiting enzyme in this process, what makes it a promising potential therapeutic target. However, currently it is still unclear what consequences the inhibition of PK has on cellular processes. Here, we systematically investigate the consequences of PK depletion for gene expression, histone modifications and metabolism.
METHODS
Epigenetic, transcriptional and metabolic targets were analysed in different cellular and animal models with stable knockdown or knockout of PK.
RESULTS
Depleting PK activity reduces the glycolytic flux and causes accumulation of glucose-6-phosphate (G6P). Such metabolic perturbation results in stimulation of the activity of a heterodimeric pair of transcription factors MondoA and MLX but not in a major reprogramming of the global H3K9ac and H3K4me3 histone modification landscape. The MondoA:MLX heterodimer upregulates expression of thioredoxin-interacting protein (TXNIP) - a tumour suppressor with multifaceted anticancer activity. This effect of TXNIP upregulation extends beyond immortalised cancer cell lines and is applicable to multiple cellular and animal models.
CONCLUSIONS
Our work shows that actions of often pro-tumorigenic PK and anti-tumorigenic TXNIP are tightly linked via a glycolytic intermediate. We suggest that PK depletion stimulates the activity of MondoA:MLX transcription factor heterodimers and subsequently, increases cellular TXNIP levels. TXNIP-mediated inhibition of thioredoxin (TXN) can reduce the ability of cells to scavenge reactive oxygen species (ROS) leading to the oxidative damage of cellular structures including DNA. These findings highlight an important regulatory axis affecting tumour suppression mechanisms and provide an attractive opportunity for combination cancer therapies targeting glycolytic activity and ROS-generating pathways.
Topics: Animals; Pyruvate Kinase; Reactive Oxygen Species; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Neoplasms; Thioredoxins
PubMed: 37290673
DOI: 10.1016/j.molmet.2023.101748 -
Journal of Respiratory Biology and... Jun 2024The molecular mechanisms that regulate progressive pulmonary fibrosis remain poorly understood. Type 2 alveolar epithelial cells (AEC2s) function as adult stem cells in...
The molecular mechanisms that regulate progressive pulmonary fibrosis remain poorly understood. Type 2 alveolar epithelial cells (AEC2s) function as adult stem cells in the lung. We previously showed that there is a loss of AEC2s and a failure of AEC2 renewal in the lungs of idiopathic pulmonary fibrosis (IPF) patients. We also reported that beta-arrestins are the key regulators of fibroblast invasion, and beta-arrestin 1 and 2 deficient mice exhibit decreased mortality, decreased matrix deposition, and increased lung function in bleomycin-induced lung fibrosis. However, the role of beta-arrestins in AEC2 regeneration is unclear. In this study, we investigated the role and mechanism of Arrestin beta 1 (ARRB1) in AEC2 renewal and in lung fibrosis. We used conventional deletion as well as cell type-specific deletion of in mice and found that deficiency in fibroblasts protects mice from lung fibrosis, and the knockout mice exhibit enhanced AEC2 regeneration in vivo, suggesting a role of fibroblast-derived ARRB1 in AEC2 renewal. We further found that -deficient fibroblasts promotes AEC2 renewal in 3D organoid assays. Mechanistically, we found that CCL7 is among the top downregulated cytokines in deficient fibroblasts and CCL7 inhibits AEC2 regeneration in 3D organoid experiments. Therefore, fibroblast ARRB1 mediates AEC2 renewal, possibly by releasing chemokine CCL7, leading to fibrosis in the lung.
PubMed: 38736470
DOI: 10.35534/jrbtm.2024.10006 -
Frontiers in Pharmacology 2023Modern methods for quantifying signaling bias at G protein-coupled receptors (GPCRs) rely on using a single β-arrestin isoform. However, it is increasingly appreciated...
Modern methods for quantifying signaling bias at G protein-coupled receptors (GPCRs) rely on using a single β-arrestin isoform. However, it is increasingly appreciated that the two β-arrestin isoforms have unique roles, requiring the ability to assess β-arrestin isoform preference. Thus, methods are needed to efficiently screen the recruitment of both β-arrestin isoforms as they compete for a target GPCR in cells. We used molecular cloning to develop fusion proteins of the δ-opioid receptor (δOR), β-arrestin 1, and β-arrestin 2 to fragments of click beetle green and click beetle red luciferases. In this assay architecture, recruitment of either β-arrestin 1 or 2 to the δOR generates a spectrally distinct bioluminescent signal, allowing us to co-transfect all three constructs into cells prior to agonist challenge. We demonstrate that our new assay, named "ClickArr," is a live-cell assay that simultaneously reports the recruitment of both β-arrestin isoforms as they compete for interaction with the δOR. We further find that the partial δOR agonist TAN67 has a significant efficacy bias for β-arrestin 2 over β-arrestin 1 when recruitment is normalized to the reference agonist leu-enkephalin. We confirm that ClickArr reports this bias when run either as a high-throughput endpoint or high-throughput kinetic assay, and cross-validate this result using the PathHunter assay, an orthogonal commercial assay for reporting β-arrestin recruitment to the δOR. Our results suggest that agonist:GPCR complexes can have relative β-arrestin isoform bias, a novel signaling bias that may potentially open up a new dimension for drug development.
PubMed: 38027002
DOI: 10.3389/fphar.2023.1295518 -
Circulation Research Jun 2024GPCRs (G protein-coupled receptors), also known as 7 transmembrane domain receptors, are the largest receptor family in the human genome, with ≈800 members. GPCRs... (Review)
Review
GPCRs (G protein-coupled receptors), also known as 7 transmembrane domain receptors, are the largest receptor family in the human genome, with ≈800 members. GPCRs regulate nearly every aspect of human physiology and disease, thus serving as important drug targets in cardiovascular disease. Sharing a conserved structure comprised of 7 transmembrane α-helices, GPCRs couple to heterotrimeric G-proteins, GPCR kinases, and β-arrestins, promoting downstream signaling through second messengers and other intracellular signaling pathways. GPCR drug development has led to important cardiovascular therapies, such as antagonists of β-adrenergic and angiotensin II receptors for heart failure and hypertension, and agonists of the glucagon-like peptide-1 receptor for reducing adverse cardiovascular events and other emerging indications. There continues to be a major interest in GPCR drug development in cardiovascular and cardiometabolic disease, driven by advances in GPCR mechanistic studies and structure-based drug design. This review recounts the rich history of GPCR research, including the current state of clinically used GPCR drugs, and highlights newly discovered aspects of GPCR biology and promising directions for future investigation. As additional mechanisms for regulating GPCR signaling are uncovered, new strategies for targeting these ubiquitous receptors hold tremendous promise for the field of cardiovascular medicine.
Topics: Humans; Receptors, G-Protein-Coupled; Animals; Cardiovascular Diseases; Signal Transduction; Drug Discovery; History, 21st Century; History, 20th Century
PubMed: 38900852
DOI: 10.1161/CIRCRESAHA.124.323067 -
Cell Death & Disease Feb 2024Previous study showed that higher expression of prolactin (PRL) was found in CRPC samples compared with hormone-naive prostate cancer (HNPC) and benign prostatic...
Previous study showed that higher expression of prolactin (PRL) was found in CRPC samples compared with hormone-naive prostate cancer (HNPC) and benign prostatic hyperplasia (BPH) samples. We further investigate the function of PRL in prostate cancer (PCa) and explored its downstream effects. We found heterogeneous expression of the PRLR in clinical prostate samples. The VCaP and 22Rv1 cells exhibited PRLR expression. Among the downstream proteins, STAT5B was the dominant subtype in clinical samples and cell lines. Human recombinant PRL stimulation of PCa cells with PRLR expression resulted in increased phosphorylation of STAT5B(pSTAT5B) and progression of PCa in vitro and in vivo, and STAT5B knockdown can suppress the malignant behavior of PCa. To understand the mechanism further, we performed Bioinformatic analysis, ChIP qPCR, and luciferase reporter gene assay. The results revealed that ARRB2 was the transcription target gene of STAT5B, and higher expression of ARRB2 was related to higher aggression and poorer prognosis of PCa. Additionally, Gene set enrichment analysis indicated that higher expression of ARRB2 was significantly enriched in the MAPK signaling pathway. Immunohistochemistry (IHC) demonstrated elevated pSTAT5B, ARRB2, and pERK1/2 expression levels in CRPC tissues compared to HNPC and BPH. Mechanically, ARRB2 enhanced the activation of the MAPK pathway by binding to ERK1/2, thereby promoting the phosphorylation of ERK1/2 (pERK1/2). In conclusion, our study demonstrated that PRL stimulation can promote the progression of PCa through STAT5B/ARRB2 pathway and activation of MAPK signaling, which can be suppressed by intervention targeting STAT5B. Blockade of the STAT5B can be a potential therapeutic target for PCa.
Topics: Male; Humans; Prolactin; Prostatic Hyperplasia; Prostatic Neoplasms, Castration-Resistant; Prostatic Neoplasms; Receptors, Prolactin; Phosphorylation; Cell Line, Tumor; STAT5 Transcription Factor; beta-Arrestin 2
PubMed: 38341429
DOI: 10.1038/s41419-023-06362-2 -
Pharmacological Reviews Feb 2024Type 2 diabetes (T2D) mellitus has emerged as a major global health concern that has accelerated in recent years due to poor diet and lifestyle. Afflicted individuals... (Review)
Review
Type 2 diabetes (T2D) mellitus has emerged as a major global health concern that has accelerated in recent years due to poor diet and lifestyle. Afflicted individuals have high blood glucose levels that stem from the inability of the pancreas to make enough insulin to meet demand. Although medication can help to maintain normal blood glucose levels in individuals with chronic disease, many of these medicines are outdated, have severe side effects, and often become less efficacious over time, necessitating the need for insulin therapy. G protein-coupled receptors (GPCRs) regulate many physiologic processes, including blood glucose levels. In pancreatic cells, GPCRs regulate -cell growth, apoptosis, and insulin secretion, which are all critical in maintaining sufficient -cell mass and insulin output to ensure euglycemia. In recent years, new insights into the signaling of incretin receptors and other GPCRs have underscored the potential of these receptors as desirable targets in the treatment of diabetes. The signaling of these receptors is modulated by GPCR kinases (GRKs) that phosphorylate agonist-activated GPCRs, marking the receptor for arrestin binding and internalization. Interestingly, genome-wide association studies using diabetic patient cohorts link the GRKs and arrestins with T2D. Moreover, recent reports show that GRKs and arrestins expressed in the cell serve a critical role in the regulation of -cell function, including -cell growth and insulin secretion in both GPCR-dependent and -independent pathways. In this review, we describe recent insights into GPCR signaling and the importance of GRK function in modulating -cell physiology. SIGNIFICANCE STATEMENT: Pancreatic cells contain a diverse array of G protein-coupled receptors (GPCRs) that have been shown to improve -cell function and survival, yet only a handful have been successfully targeted in the treatment of diabetes. This review discusses recent advances in our understanding of -cell GPCR pharmacology and regulation by GPCR kinases while also highlighting the necessity of investigating islet-enriched GPCRs that have largely been unexplored to unveil novel treatment strategies.
Topics: Humans; Diabetes Mellitus, Type 2; Blood Glucose; Genome-Wide Association Study; Insulin-Secreting Cells; Receptors, G-Protein-Coupled; G-Protein-Coupled Receptor Kinases; Arrestins; Insulins; Phosphorylation
PubMed: 38351071
DOI: 10.1124/pharmrev.123.001015 -
Theranostics 2024Neurons in the ventral tegmental area (VTA) are sensitive to stress and their maladaptation have been implicated in the psychiatric disorders such as anxiety and...
Neurons in the ventral tegmental area (VTA) are sensitive to stress and their maladaptation have been implicated in the psychiatric disorders such as anxiety and addiction, . The cellular properties of the VTA neurons in response to different stressors related to different emotional processing remain to be investigated. By combining immediate early gene (IEG)-dependent labeling, rabies virus tracing, ensemble-specific transcriptomic analysis and fiber photometry recording in the VTA of male mice, the spatial distribution, brain-wide connectivity and cellular signaling pathways in the VTA neuronal ensembles in response to morphine (Mor-Ens) or foot shock (Shock-Ens) stimuli were investigated. Optogenetic activation of the Mor-Ens drove approach behavior, whereas chemogenetic activation of the Shock-Ens increased the anxiety level in mice. Mor-Ens were clustered and enriched in the ventral VTA, contained a higher proportion of dopaminergic neurons, received more inputs from the dorsal medial striatum and the medial hypothalamic zone, and exhibited greater axonal arborization in the zona incerta and ventral pallidum. Whereas Shock-Ens were more dispersed, contained a higher proportion of GABAergic neurons, and received more inputs from the ventral pallidum and the lateral hypothalamic area. The downstream targets of the G protein and β-arrestin pathways, PLCβ3 and phosphorylated AKT1, were relatively enriched in the Mor-Ens and Shock-Ens, respectively. Cariprazine, the G-protein-biased agonist for the dopamine D2 receptor, increased the response of Mor-Ens to sucrose water and decreased the anxiety-like behavior during morphine withdrawal, whereas the β-arrestin-biased agonist UNC9994 decreased the response of Shock-Ens to tail suspension. Taken together, these findings reveal the heterogeneous connectivity and signaling pathways of the VTA neurons in response to morphine and foot shock, providing new insights for development of specific interventions for psychiatric disorders caused by various stressors associated with different VTA neuronal functions.
Topics: Humans; Male; Animals; Mice; Ventral Tegmental Area; Dopaminergic Neurons; Signal Transduction; beta-Arrestins; Morphine Derivatives
PubMed: 38250036
DOI: 10.7150/thno.90792 -
BioRxiv : the Preprint Server For... May 2024G protein-coupled receptors (GPCRs) control intracellular signaling cascades via agonist-dependent coupling to intracellular transducers including heterotrimeric G...
G protein-coupled receptors (GPCRs) control intracellular signaling cascades via agonist-dependent coupling to intracellular transducers including heterotrimeric G proteins, GPCR kinases (GRKs), and arrestins. In addition to their critical interactions with the transmembrane core of active GPCRs, all three classes of transducers have also been reported to interact with receptor C-terminal domains (CTDs). An underexplored aspect of GPCR CTDs is their possible role as lipid sensors given their proximity to the membrane. CTD-membrane interactions have the potential to control the accessibility of key regulatory CTD residues to downstream effectors and transducers. Here we report that the CTDs of two closely related family C GPCRs, metabotropic glutamate receptor 2 (mGluR2) and mGluR3, bind to membranes and that this interaction can regulate receptor function. We first characterize CTD structure with NMR spectroscopy, revealing lipid composition-dependent modes of membrane binding. Using molecular dynamics simulations and structure-guided mutagenesis, we then identify key conserved residues and cancer-associated mutations that modulate CTD-membrane binding. Finally, we provide evidence that mGluR3 transducer coupling is controlled by CTD-membrane interactions in live cells, which may be subject to regulation by CTD phosphorylation and changes in membrane composition. This work reveals a novel mechanism of GPCR modulation, suggesting that CTD-membrane binding may be a general regulatory mode throughout the broad GPCR superfamily.
PubMed: 37645938
DOI: 10.1101/2023.08.16.553551