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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 -
Naunyn-Schmiedeberg's Archives of... May 2024The present study aimed to evaluate the possible peripheral HO-induced antinociception and determine the involvement of opioidergic, cannabinoidergic and nitrergic...
The present study aimed to evaluate the possible peripheral HO-induced antinociception and determine the involvement of opioidergic, cannabinoidergic and nitrergic systems, besides potassium channels in its antinociceptive effect. Prostaglandin E was used to induce hyperalgesia in male Swiss mice using the mechanical paw pressure test. HO (0.1, 0.2, 0.3 µg/paw) promoted a dose-dependent antinociceptive effect that was not observed in contralateral paw. Female mice also showed antinociception in the model. The partial HO-induced antinociception was potentiated by the inhibitor of catalase enzyme, aminotriazole (40, 60, 80 µg/paw). The antinociception was not reversed by opioid and cannabinoid receptor antagonists naloxone, AM 251 and AM 630. The involvement of nitric oxide (NO) was observed by the reversal of HO-induced antinociception using the non-selective inhibitor of nitric oxide synthases L-NOarg and by inhibition of iNOS (L-NIL), eNOS (L-NIO) and nNOS (L-NPA). ODQ, a cGMP-forming enzyme selective inhibitor, also reversed the antinociception. The blockers of potassium channels voltage-gated (TEA), ATP-sensitive (glibenclamide), large (paxillin) and small (dequalinium) conductance calcium-activated were able to revert HO antinociception. Our data suggest that HO induced a peripheral antinociception in mice and the NO pathway and potassium channels (voltage-gated, ATP-sensitive, calcium-activated) are involved in this mechanism. However, the role of the opioid and cannabinoid systems was not evidenced.
PubMed: 38753048
DOI: 10.1007/s00210-024-03087-7 -
Research in Veterinary Science Jul 2024Avian pathogenic Escherichia coli (APEC) is a widespread bacterium that causes significant economic losses to the poultry industry. APEC biofilm formation may result in...
Avian pathogenic Escherichia coli (APEC) is a widespread bacterium that causes significant economic losses to the poultry industry. APEC biofilm formation may result in chronic, persistent, and recurrent infections in clinics, making treatment challenging. Baicalein is a natural product that exhibits antimicrobial and antibiofilm activities. This study investigates the inhibitory effect of baicalein on APEC biofilm formation at different stages. The minimum inhibitory concentration (MIC) of baicalein on APEC was determined, and the growth curve of APEC biofilm formation was determined. The effects of baicalein on APEC biofilm adhesion, accumulation, and maturation were observed using optical microscopy, confocal laser scanning microscopy, and scanning electron microscopy. The biofilm inhibition rate of baicalein was calculated at different stages. The MIC of baicalein against APEC was 256 μg/mL. The process of APEC biofilm maturation takes approximately 48 h after incubation, with initial adhesion completed at 12 h, and cell accumulation finished at 24 h. Baicalein had a significant inhibitory effect on APEC biofilm formation at concentrations above 1 μg/mL (p < 0.01). Notably, baicalein had the highest rate of biofilm formation inhibition when added at the adhesion stage. Therefore, it can be concluded that baicalein is a potent inhibitor of APEC biofilm formation in vitro and acts, primarily by inhibiting cell adhesion. These findings suggests that baicalein has a potential application for inhibiting APEC biofilm formation and provides a novel approach for the prevention and control APEC-related diseases.
Topics: Flavanones; Biofilms; Escherichia coli; Bacterial Adhesion; Animals; Microbial Sensitivity Tests; Anti-Bacterial Agents; Poultry Diseases; Chickens; Escherichia coli Infections; Microscopy, Electron, Scanning
PubMed: 38729095
DOI: 10.1016/j.rvsc.2024.105291 -
Molecular Biology Reports May 2024Baicalein is the main active flavonoid in Scutellariae Radix and is included in shosaikoto, a Kampo formula used for treating hepatitis and jaundice. However, little is...
BACKGROUND
Baicalein is the main active flavonoid in Scutellariae Radix and is included in shosaikoto, a Kampo formula used for treating hepatitis and jaundice. However, little is known about its hepatoprotective effects against hepatic ischemia-reperfusion injury (HIRI), a severe clinical condition directly caused by interventional procedures. We aimed to investigate the hepatoprotective effects of baicalein against HIRI and partial hepatectomy (HIRI + PH) and its potential underlying mechanisms.
METHODS AND RESULTS
Male Sprague-Dawley rats received either baicalein (5 mg/kg) or saline intraperitoneally and underwent a 70% hepatectomy 15 min after hepatic ischemia. After reperfusion, liver and blood samples were collected. Survival was monitored 30 min after hepatic ischemia and hepatectomy. In interleukin 1β (IL-1β)-treated primary cultured rat hepatocytes, the influence of baicalein on inflammatory mediator production and the associated signaling pathway was analyzed. Baicalein suppressed apoptosis and neutrophil infiltration, which are the features of HIRI + PH treatment-induced histological injury. Baicalein also reduced the mRNA expression of the proinflammatory cytokine tumor necrosis factor-α (TNF-α). In addition, HIRI + PH treatment induced liver enzyme deviations in the serum and hypertrophy of the remnant liver, which were suppressed by baicalein. In the lethal HIRI + PH treatment group, baicalein significantly reduced mortality. In IL-1β-treated rat hepatocytes, baicalein suppressed TNF-α and chemokine mRNA expression as well as the activation of nuclear factor-kappa B (NF-κB) and Akt.
CONCLUSIONS
Baicalein treatment attenuates HIRI + PH-induced liver injury and may promote survival. This potential hepatoprotection may be partly related to suppressing inflammatory gene induction through the inhibition of NF-κB activity and Akt signaling in hepatocytes.
Topics: Animals; Flavanones; Reperfusion Injury; Hepatectomy; Male; Rats; Rats, Sprague-Dawley; Liver; Hepatocytes; Disease Models, Animal; Apoptosis; Interleukin-1beta; NF-kappa B; Protective Agents; Signal Transduction; Tumor Necrosis Factor-alpha; Proto-Oncogene Proteins c-akt
PubMed: 38727775
DOI: 10.1007/s11033-024-09548-9 -
Phytomedicine : International Journal... Jul 2024The pathogenesis of lower respiratory tract infections (LRTIs) has been demonstrated to be strongly associated with dysbiosis of respiratory microbiota. Scutellaria...
BACKGROUND
The pathogenesis of lower respiratory tract infections (LRTIs) has been demonstrated to be strongly associated with dysbiosis of respiratory microbiota. Scutellaria baicalensis, a traditional Chinese medicine, is widely used to treat respiratory infections. However, whether the therapeutic effect of S. baicalensis on LRTIs depends upon respiratory microbiota regulation is largely unclear.
PURPOSE
To investigate the potential effect and mechanism of S. baicalensis on the respiratory microbiota of LRTI mice.
METHODS
A mouse model of LRTI was established using Klebsiella pneumoniae or Streptococcus pneumoniae. Antibiotic treatment was administered, and transplantation of respiratory microbiota was performed to deplete the respiratory microbiota of mice and recover the destroyed microbial community, respectively. High-performance liquid chromatography (HPLC) was used to determine and quantify the chemical components of S. baicalensis water decoction (SBWD). Pathological changes in lung tissues and the expressions of serum inflammatory cytokines, including interleukin-17A (IL-17A), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), were determined by hematoxylin and eosin (H&E) staining and enzyme-linked immunosorbent assay (ELISA), respectively. Quantitative real-time PCR (qRT-PCR) analysis was performed to detect the mRNA expression of GM-CSF. Metagenomic sequencing was performed to evaluate the effect of SBWD on the composition and function of the respiratory microbiota in LRTI mice.
RESULTS
Seven main components, including scutellarin, baicalin, oroxylin A-7-O-β-d-glucuronide, wogonoside, baicalein, wogonin, and oroxylin A, were identified and their levels in SBWD were quantified. SBWD ameliorated pulmonary pathological injury and inflammatory responses in K. pneumoniae and S. pneumoniae-induced LRTI mice, as evidenced by the dose-dependent reductions in the levels of serum inflammatory cytokines, IL-6 and TNF-α. SBWD may exert a bidirectional regulatory effect on the host innate immune responses in LRTI mice and regulate the expressions of IL-17A and GM-CSF in a microbiota-dependent manner. K. pneumoniae infection but not S. pneumoniae infection led to dysbiosis in the respiratory microbiota, evident through disturbances in the taxonomic composition characterized by bacterial enrichment, including Proteobacteria, Enterobacteriaceae, and Klebsiella. K. pneumoniae and S. pneumoniae infection altered the bacterial functional profile of the respiratory microbiota, as indicated by increases in lipopolysaccharide biosynthesis, metabolic pathways, and carbohydrate metabolism. SBWD had a certain trend on the regulation of compositional disorders in the respiratory flora and modulated partial microbial functions embracing carbohydrate metabolism in K. pneumoniae-induced LRTI mice.
CONCLUSION
SBWD may exert an anti-infection effect on LRTI by targeting IL-17A and GM-CSF through respiratory microbiota regulation. The mechanism of S. baicalensis action on respiratory microbiota in LRTI treatment merits further investigation.
Topics: Animals; Scutellaria baicalensis; Lung; Mice; Klebsiella pneumoniae; Microbiota; Respiratory Tract Infections; Plant Extracts; Male; Streptococcus pneumoniae; Cytokines; Disease Models, Animal; Drugs, Chinese Herbal; Flavanones; Mice, Inbred C57BL; Klebsiella Infections; Flavonoids; Pneumococcal Infections; Apigenin; Dysbiosis
PubMed: 38723528
DOI: 10.1016/j.phymed.2024.155706 -
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 -
Acta Pharmacologica Sinica May 2024It has been shown that prostaglandin (PG) E synthesized in the lateral parabrachial nucleus (LPBN) is involved in lipopolysaccharide-induced fever. But the neural...
It has been shown that prostaglandin (PG) E synthesized in the lateral parabrachial nucleus (LPBN) is involved in lipopolysaccharide-induced fever. But the neural mechanisms of how intra-LPBN PGE induces fever remain unclear. In this study, we investigated whether the LPBN-preoptic area (POA) pathway, the thermoafferent pathway for feed-forward thermoregulatory responses, mediates fever induced by intra-LPBN PGE in male rats. The core temperature (T) was monitored using a temperature radiotelemetry transponder implanted in rat abdomen. We showed that microinjection of PGE (0.28 nmol) into the LPBN significantly enhanced the density of c-Fos-positive neurons in the median preoptic area (MnPO). The chemical lesioning of MnPO with ibotenate or selective genetic lesioning or inhibition of the LPBN-MnPO pathway significantly attenuated fever induced by intra-LPBN injection of PGE. We demonstrated that EP3 receptor was a pivotal receptor for PGE-induced fever, since microinjection of EP3 receptor agonist sulprostone (0.2 nmol) or EP3 receptor antagonist L-798106 (2 nmol) into the LPBN mimicked or weakened the pyrogenic action of LPBN PGE, respectively, but this was not the case for EP4 and EP1 receptors. Whole-cell recording from acute LPBN slices revealed that the majority of MnPO-projecting neurons originating from the external lateral (el) and dorsal (d) LPBN were excited and inhibited, respectively, by PGE perfusion, initiating heat-gain and heat-loss mechanisms. The amplitude but not the frequency of spontaneous and miniature glutamatergic excitatory postsynaptic currents (sEPSCs and mEPSCs) in MnPO-projecting LPBel neurons increased after perfusion with PGE; whereas the frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs) and the A-type potassium (I) current density did not change. In MnPO-projecting LPBd neurons, neither sEPSCs nor sIPSCs responded to PGE; however, the I current density was significantly increased by PGE perfusion. These electrophysiological responses and the thermoeffector reactions to intra-LPBN PGE injection, including increased brown adipose tissue thermogenesis, shivering, and decreased heat dissipation, were all abolished by L-798106, and mimicked by sulprostone. These results suggest that the pyrogenic effects of intra-LPBN PGE are mediated by both the inhibition of the LPBd-POA pathway through the EP3 receptor-mediated activation of I currents and the activation of the LPBel-POA pathway through the selective enhancement of glutamatergic synaptic transmission via EP3 receptors.
PubMed: 38702500
DOI: 10.1038/s41401-024-01289-6 -
Proceedings of the National Academy of... May 2024EPH receptors (EPHs), the largest family of tyrosine kinases, phosphorylate downstream substrates upon binding of ephrin cell surface-associated ligands. In a large...
EPH receptors (EPHs), the largest family of tyrosine kinases, phosphorylate downstream substrates upon binding of ephrin cell surface-associated ligands. In a large cohort of endometriotic lesions from individuals with endometriosis, we found that and expressions are increased in endometriotic lesions relative to normal eutopic endometrium. Because signaling through EPHs is associated with increased cell migration and invasion, we hypothesized that chemical inhibition of EPHA2/4 could have therapeutic value. We screened DNA-encoded chemical libraries (DECL) to rapidly identify EPHA2/4 kinase inhibitors. Hit compound, CDD-2693, exhibited picomolar/nanomolar kinase activity against EPHA2 (K: 4.0 nM) and EPHA4 (K: 0.81 nM). Kinome profiling revealed that CDD-2693 bound to most EPH family and SRC family kinases. Using NanoBRET target engagement assays, CDD-2693 had nanomolar activity versus EPHA2 (IC: 461 nM) and EPHA4 (IC: 40 nM) but was a micromolar inhibitor of SRC, YES, and FGR. Chemical optimization produced CDD-3167, having picomolar biochemical activity toward EPHA2 (K: 0.13 nM) and EPHA4 (K: 0.38 nM) with excellent cell-based potency EPHA2 (IC: 8.0 nM) and EPHA4 (IC: 2.3 nM). Moreover, CDD-3167 maintained superior off-target cellular selectivity. In 12Z endometriotic epithelial cells, CDD-2693 and CDD-3167 significantly decreased EFNA5 (ligand) induced phosphorylation of EPHA2/4, decreased 12Z cell viability, and decreased IL-1β-mediated expression of prostaglandin synthase 2 (). CDD-2693 and CDD-3167 decreased expansion of primary endometrial epithelial organoids from patients with endometriosis and decreased Ewing's sarcoma viability. Thus, using DECL, we identified potent pan-EPH inhibitors that show specificity and activity in cellular models of endometriosis and cancer.
Topics: Humans; Female; Protein Kinase Inhibitors; Endometriosis; DNA; Receptors, Eph Family; Receptor, EphA2; Small Molecule Libraries; Cell Movement
PubMed: 38701119
DOI: 10.1073/pnas.2322934121