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Nature Communications May 2024Resolving 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...
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 (PGE) 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 PGE 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.
Topics: Animals; Pneumonia, Pneumococcal; Disease Models, Animal; Mice; Dinoprostone; Mice, Inbred C57BL; Streptococcus pneumoniae; Receptors, Prostaglandin E, EP4 Subtype; Macrophages; Lung; Macrophages, Alveolar; Integrin alpha Chains; Female; Antigens, CD; T-Lymphocytes
PubMed: 38773113
DOI: 10.1038/s41467-024-48138-y -
PloS One 2024This study seeks to investigate the impact of co-administering either a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist alone with a low dose BMP7 on in...
PURPOSE
This study seeks to investigate the impact of co-administering either a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist alone with a low dose BMP7 on in vitro healing process, collagen content and maturation of human osteoblasts.
METHODOLOGY
Human osteoblast cells were used in this study. These cells were cultured and subjected to different concentrations of Prostaglandin EP2 receptor agonist, EP1 receptor antagonist, BMP7, Control (Ct) (Vehicle alone), and various combinations treatments. Cell viability at 24, 48 and 72 hours (h) was evaluated using the XTT assay. A wound healing assay was conducted to observe the migration ability of human osteoblast cells. Additionally, Sirius red staining and Fourier-Transform Infrared Spectroscopy Imaging (FT-IR) was employed to analyze various parameters, including total protein concentration, collagen production, mature collagen concentration, and mineral content.
RESULTS
The combination of low dose BMP7 and Prostaglandin EP2 receptor agonist resulted to the lowest cell viability when compared to both the Ct and individual treatments. In contrast, the Prostaglandin EP1 receptor antagonist alone showed the highest cellular viability at 72 h. In the wound healing assay, the combined treatment of low dose BMP7 with the Prostaglandin EP2 receptor agonist and EP1 receptor antagonist showed a decrease in human osteoblast healing after 24 h. Analysis of FT-IR data indicated a reduction in total protein content, collagen maturity, collagen concentration and mineral content in combination treatment compared to the single or Ct treatments.
CONCLUSION
The combination of a Prostaglandin EP2 receptor agonist or an EP1 receptor antagonist when combined with low dose BMP7 significantly hinders both human osteoblast healing and collagen maturity/concentration in comparison to low dose BMP7 treatment alone.
Topics: Humans; Osteoblasts; Collagen; Bone Morphogenetic Protein 7; Cell Survival; Receptors, Prostaglandin E, EP2 Subtype; Wound Healing; Cell Movement; Receptors, Prostaglandin E, EP1 Subtype; Spectroscopy, Fourier Transform Infrared; Cell Line
PubMed: 38753641
DOI: 10.1371/journal.pone.0303202 -
CNS Neuroscience & Therapeutics May 2024γ-aminobutyric acid (GABA) from reactive astrocytes is critical for the dysregulation of neuronal activity in various neuroinflammatory conditions. While Scutellaria...
AIMS
γ-aminobutyric acid (GABA) from reactive astrocytes is critical for the dysregulation of neuronal activity in various neuroinflammatory conditions. While Scutellaria baicalensis Georgi (S. baicalensis) is known for its efficacy in addressing neurological symptoms, its potential to reduce GABA synthesis in reactive astrocytes and the associated neuronal suppression remains unclear. This study focuses on the inhibitory action of monoamine oxidase B (MAO-B), the key enzyme for astrocytic GABA synthesis.
METHODS
Using a lipopolysaccharide (LPS)-induced neuroinflammation mouse model, we conducted immunohistochemistry to assess the effect of S. baicalensis on astrocyte reactivity and its GABA synthesis. High-performance liquid chromatography was performed to reveal the major compounds of S. baicalensis, the effects of which on MAO-B inhibition, astrocyte reactivity, and tonic inhibition in hippocampal neurons were validated by MAO-B activity assay, qRT-PCR, and whole-cell patch-clamp.
RESULTS
The ethanolic extract of S. baicalensis ameliorated astrocyte reactivity and reduced excessive astrocytic GABA content in the CA1 hippocampus. Baicalin and baicalein exhibited significant MAO-B inhibition potential. These two compounds downregulate the mRNA levels of genes associated with reactive astrogliosis or astrocytic GABA synthesis. Additionally, LPS-induced aberrant tonic inhibition was reversed by both S. baicalensis extract and its key compounds.
CONCLUSIONS
In summary, baicalin and baicalein isolated from S. baicalensis reduce astrocyte reactivity and alleviate aberrant tonic inhibition of hippocampal neurons during neuroinflammation.
Topics: Animals; Astrocytes; Flavanones; Scutellaria baicalensis; Mice; gamma-Aminobutyric Acid; Neurons; Male; Flavonoids; Plant Extracts; Lipopolysaccharides; Mice, Inbred C57BL; Monoamine Oxidase; Neural Inhibition; Hippocampus
PubMed: 38715318
DOI: 10.1111/cns.14740 -
Poultry Science Jul 2024Baicalein (BAI) is a natural flavonoid with antioxidant, antitumor and antibacterial properties. However, the bioavailability of BAI was limited due to low solubility....
The baicalein amorphous solid dispersion to enhance the dissolution and bioavailability and effects on growth performance, meat quality, antioxidant capacity and intestinal flora in Taihang chickens.
Baicalein (BAI) is a natural flavonoid with antioxidant, antitumor and antibacterial properties. However, the bioavailability of BAI was limited due to low solubility. This study aims to improve the solubility of BAI through the amorphous solid dispersion (ASD) and evaluate changes in its pharmacokinetics and pharmacodynamics in Taihang chickens. Polyethylene caprolactam-polyvinyl acetate-polyethylene glycol grafted copolymer (Soluplus) was chosen as the carrier, and ASD was prepared by rotary evaporation and was characterized by powder X-ray diffractions (PXRD), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR). In vitro dissolution assays were used to screen the optimal ratio of drug to carrier, in vivo pharmacokinetic assays were conducted to investigate the promoting effect on the absorption. In addition, the effects of ASD on the growth performance, meat quality, antioxidant capacity and intestinal flora were investigated. ASD (1:9 and 2:8) did not exhibit crystal diffraction peaks of BAI in PXRD or endothermic peaks in DSC, indicating the successful preparation of ASD. The results of in vitro dissolution assay showed that the cumulative dissolution rate of ASD (2:8) within 600 min was 52.67%, which was 7.84-fold higher than BAI. The pharmacokinetic results showed that the peak concentration (C) and the area under the drug-time curve (AUC) of ASD (2:8) was (5.20 ± 0.82) μg/mL and (17.03 ± 0.67) μg·h/mL, which was 1.91 and 2.64-fold higher than BAI, respectively. Dietary supplementation of BAI and ASD could increase average daily gain (ADG), while decrease feed conversion ratio (FCR), but there was no significant difference (P > 0.05). The drip loss of BAIASD group was lower than BAI group (P < 0.05). In addition, the antioxidant capacity of Taihang chickens were enhanced, the diversity and the abundance of beneficial bacteria was improved. Results of BAI upon the dietary supplementation tested in Taihang chickens, after preparation of ASD, indicating a superior enhancement effect in growth performance, meat quality, antioxidant capacity and intestinal flora due to an improved solubility and optimized bioavailability.
Topics: Animals; Chickens; Biological Availability; Antioxidants; Flavanones; Meat; Animal Feed; Gastrointestinal Microbiome; Solubility; Diet; Polyvinyls; Male; Polyethylene Glycols; Dietary Supplements
PubMed: 38703758
DOI: 10.1016/j.psj.2024.103768 -
Frontiers in Bioscience (Landmark... Apr 2024Diabetic bladder dysfunction (DBD) is driven in part by inflammation which dysregulates prostaglandin release in the bladder. Precise inflammatory mechanisms responsible...
BACKGROUND
Diabetic bladder dysfunction (DBD) is driven in part by inflammation which dysregulates prostaglandin release in the bladder. Precise inflammatory mechanisms responsible for such dysregulation have been elusive. Since prostaglandins impact bladder contractility, elucidating these mechanisms may yield potential therapeutic targets for DBD. In female Type 1 diabetic Akita mice, inflammation mediated by the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome is responsible for DBD. Here, we utilized female Akita mice crossbred with knock-out mice to determine how NLRP3-driven inflammation impacts prostaglandin release within the bladder and prostaglandin-mediated bladder contractions.
METHODS
Akita mice were crossbred with mice to yield four groups of non-diabetics and diabetics with and without the gene. Females were aged to 30 weeks when Akitas typically exhibit DBD. Urothelia and detrusors were stretched to release prostaglandins. Prostaglandin E2 (PGE2) and prostaglandin F2α (PGF2α) were quantified using enzyme linked immunosorbent assays (ELISA). In separate samples, contractile force to PGE2 and PGF2α +/- the prostaglandin F (FP) receptor antagonist, AL8810, was measured. FP receptor protein expression was determined via western blotting.
RESULTS
Stretch-induced PGE2 release increases in urothelia but decreases in detrusors of diabetics. However, PGE2-mediated bladder contractions are not impacted. Conversely, diabetics show no changes in PGF2α release, but PGF2α-mediated contractions increase significantly. This is likely due to signaling through the FP receptors as FP receptor antagonism prevents this increase and diabetics demonstrate a four-fold increase in FP receptor proteins. Without NLRP3-mediated inflammation, changes in prostaglandin release, contractility, and receptor expression do not occur.
CONCLUSION
NLRP3-dependent inflammation dysregulates prostaglandin release and prostaglandin-mediated bladder contractions in diabetic female Akita mice via FP receptor upregulation.
Topics: Animals; Female; NLR Family, Pyrin Domain-Containing 3 Protein; Urinary Bladder; Receptors, Prostaglandin; Muscle Contraction; Diabetes Mellitus, Type 1; Mice, Knockout; Mice; Inflammation; Mice, Inbred C57BL; Diabetes Mellitus, Experimental
PubMed: 38682210
DOI: 10.31083/j.fbl2904154 -
Human & Experimental Toxicology 2024The disruption of the immune system by viral attack is a major influencing factor in the lethality of COVID-19. Baicalein is one of the key effective compounds against...
The disruption of the immune system by viral attack is a major influencing factor in the lethality of COVID-19. Baicalein is one of the key effective compounds against COVID-19. The molecular mechanisms regarding the anti-inflammatory properties of Baicalein are still unclear. In this study, we established LPS-induced mice to elucidate the role of Baicalein in the treatment of acute lung injury (ALI) and its potential molecular mechanisms. In vivo experiments showed that Baicalein could significantly ameliorate LPS-induced acute lung injury and reduce proteinous edema in lung tissue. In addition, Baicalein inhibited M1 macrophage polarization, promote M2 macrophage polarization, and regulate inflammatory responses. Furthermore, Baicalein could inhibit the expression of protein molecules associated with pyroptosis and mitigate the lung tissue injury. In summary, we revealed the therapeutic effects of Baicalein in acute lung injury, providing the theoretical basis for its clinical application.
Topics: Flavanones; Animals; Pyroptosis; Lipopolysaccharides; Mice; Acute Lung Injury; Macrophages; Male; Mice, Inbred C57BL; Anti-Inflammatory Agents; Disease Models, Animal; Pneumonia; Lung; COVID-19 Drug Treatment; COVID-19
PubMed: 38664950
DOI: 10.1177/09603271241249990 -
Nature May 2024Expansion of antigen-experienced CD8 T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer....
Expansion of antigen-experienced CD8 T cells is critical for the success of tumour-infiltrating lymphocyte (TIL)-adoptive cell therapy (ACT) in patients with cancer. Interleukin-2 (IL-2) acts as a key regulator of CD8 cytotoxic T lymphocyte functions by promoting expansion and cytotoxic capability. 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 (PGE), a known negative regulator of immune response in the tumour microenvironment, is present at high concentrations in tumour tissue from patients and leads to impaired IL-2 sensing in human CD8 TILs via the PGE receptors EP2 and EP4. Mechanistically, PGE inhibits IL-2 sensing in TILs by downregulating the IL-2Rγ chain, resulting in defective assembly of IL-2Rβ-IL2Rγ 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 PGE 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 PGE 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.
Topics: Animals; Humans; Mice; CD8-Positive T-Lymphocytes; Cell Proliferation; Dinoprostone; Down-Regulation; Ferroptosis; Interleukin Receptor Common gamma Subunit; Interleukin-2; Interleukin-2 Receptor beta Subunit; Lymphocytes, Tumor-Infiltrating; Mitochondria; Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Receptors, Prostaglandin E, EP2 Subtype; Receptors, Prostaglandin E, EP4 Subtype; Signal Transduction; TOR Serine-Threonine Kinases; Tumor Microenvironment
PubMed: 38658764
DOI: 10.1038/s41586-024-07352-w -
International Journal of Molecular... Mar 2024Type 2 diabetes mellitus (T2DM) is marked by persistent hyperglycemia, insulin resistance, and pancreatic β-cell dysfunction, imposing substantial health burdens and...
Type 2 diabetes mellitus (T2DM) is marked by persistent hyperglycemia, insulin resistance, and pancreatic β-cell dysfunction, imposing substantial health burdens and elevating the risk of systemic complications and cardiovascular diseases. While the pathogenesis of diabetes remains elusive, a cyclical relationship between insulin resistance and inflammation is acknowledged, wherein inflammation exacerbates insulin resistance, perpetuating a deleterious cycle. Consequently, anti-inflammatory interventions offer a therapeutic avenue for T2DM management. In this study, a herb called Baikal skullcap, renowned for its repertoire of bioactive compounds with anti-inflammatory potential, is posited as a promising source for novel T2DM therapeutic strategies. Our study probed the anti-diabetic properties of compounds from Baikal skullcap via network pharmacology, molecular docking, and cellular assays, concentrating on their dual modulatory effects on diabetes through Protein Tyrosine Phosphatase 1B (PTP1B) enzyme inhibition and anti-inflammatory actions. We identified the major compounds in Baikal skullcap using liquid chromatography-mass spectrometry (LC-MS), highlighting six flavonoids, including the well-studied baicalein, as potent inhibitors of PTP1B. Furthermore, cellular experiments revealed that baicalin and baicalein exhibited enhanced anti-inflammatory responses compared to the active constituents of licorice, a known anti-inflammatory agent in TCM. Our findings confirmed that baicalin and baicalein mitigate diabetes via two distinct pathways: PTP1B inhibition and anti-inflammatory effects. Additionally, we have identified six flavonoid molecules with substantial potential for drug development, thereby augmenting the T2DM pharmacotherapeutic arsenal and promoting the integration of herb-derived treatments into modern pharmacology.
Topics: Scutellaria baicalensis; Diabetes Mellitus, Type 2; Insulin Resistance; Liquid Chromatography-Mass Spectrometry; Chromatography, Liquid; Molecular Docking Simulation; Tandem Mass Spectrometry; Flavonoids; Inflammation; Anti-Inflammatory Agents; Flavanones
PubMed: 38612466
DOI: 10.3390/ijms25073654 -
European Journal of Cell Biology Jun 2024Mesenchymal stromal cells (MSCs) that are promising for cartilage tissue engineering secrete high amounts of prostaglandin E2 (PGE2), an immunoactive mediator involved...
Mesenchymal stromal cells (MSCs) that are promising for cartilage tissue engineering secrete high amounts of prostaglandin E2 (PGE2), an immunoactive mediator involved in endochondral bone development. This study aimed to identify drivers of PGE2 and its role in the inadvertent MSC misdifferentiation into hypertrophic chondrocytes. PGE2 release, which rose in the first three weeks of MSC chondrogenesis, was jointly stimulated by endogenous BMP, WNT, and hedgehog activity that supported the exogenous stimulation by TGF-β1 and insulin to overcome the PGE2 inhibition by dexamethasone. Experiments with PGE2 treatment or the inhibitor celecoxib or specific receptor antagonists demonstrated that PGE2, although driven by prohypertrophic signals, exerted broad autocrine antihypertrophic effects. This chondroprotective effect makes PGE2 not only a promising option for future combinatorial approaches to direct MSC tissue engineering approaches into chondral instead of endochondral development but could potentially have implications for the use of COX-2-selective inhibitors in osteoarthritis pain management.
Topics: Mesenchymal Stem Cells; Chondrogenesis; Dinoprostone; Humans; Cell Differentiation; Cells, Cultured; Chondrocytes
PubMed: 38608422
DOI: 10.1016/j.ejcb.2024.151412 -
Scientific Reports Apr 2024The DP2 receptor is a G-protein coupled receptor involved in allergic inflammation and is the target of recently developed antagonists already being tested in clinics....
The DP2 receptor is a G-protein coupled receptor involved in allergic inflammation and is the target of recently developed antagonists already being tested in clinics. To get insights into DP2 receptor dynamics and to study its pharmacology on the level of the receptor, we constructed a fluorescence resonance energy transfer-based conformation sensor. The sensor reflects the selectivity profile of the DP2 receptor-wt and is suited for screening of agonists and antagonists due to its robust response. Furthermore, the sensor enables the direct measurement of DP2 receptor dynamics in real-time and revealed markedly distinct on- and off-rates of prostaglandin D between DP2 and DP1 receptors, suggesting a different mechanism of ligand receptor interaction.
Topics: Humans; Prostaglandin D2; Inflammation; Receptors, Prostaglandin
PubMed: 38589416
DOI: 10.1038/s41598-024-58410-2