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The Biochemical Journal Jun 2024While IkB-kinase-ε (IKKε) induces immunomodulatory genes following viral stimuli, its upregulation by inflammatory cytokines remains under-explored. Since airway...
While IkB-kinase-ε (IKKε) induces immunomodulatory genes following viral stimuli, its upregulation by inflammatory cytokines remains under-explored. Since airway epithelial cells respond to airborne insults and potentiate inflammation, IKKε expression was characterized in pulmonary epithelial cell lines (A549, BEAS-2B) and primary human bronchial epithelial cells (pHBECs) grown as submersion or differentiated air-liquid interface (ALI) cultures. IKKε expression was upregulated by the pro-inflammatory cytokines, IL-1β and TNF⍺. Thus, mechanistic interrogations in A549 cells were used to demonstrate the NF-κB dependence of cytokine-induced IKKε. Furthermore, chromatin immunoprecipitation in A549 and BEAS-2B cells revealed robust recruitment of the NF-κB subunit, p65, to one 5' and two intronic regions within the IKKε locus (IKBKE). In addition, IL-1β and TNFα induced strong RNA polymerase 2 recruitment to the 5' region, the first intron, and the transcription start site. Stable transfection of the p65-binding regions into A549 cells revealed IL-1β- and TNFα-inducible reporter activity that required NF-κB, but was not repressed by glucocorticoid. While critical NF-κB motifs were identified in the 5' and downstream intronic regions, the first intronic region did not contain functional NF-κB motifs. Thus, IL-1β- and TNFα-induced IKKε expression involves three NF-κB-binding regions, containing multiple functional NF-κB motifs, and potentially other mechanisms of p65 binding through non-classical NF-κB binding motifs. By enhancing IKKε expression, IL-1β may prime, or potentiate, responses to alternative stimuli, as modeled by IKKε phosphorylation induced by phorbol 12-myristate 13-acetate. However, since IKKε expression was only partially repressed by glucocorticoid, IKKε-dependent responses could contribute to glucocorticoid-resistant disease.
PubMed: 38941070
DOI: 10.1042/BCJ20230461 -
Medicina (Kaunas, Lithuania) Jun 2024: As modulators of the tumor microenvironment, macrophages have been extensively studied for their potential in developing anticancer strategies, particularly in...
: As modulators of the tumor microenvironment, macrophages have been extensively studied for their potential in developing anticancer strategies, particularly in regulating macrophage polarization towards an antitumorigenic (M1) phenotype rather than a protumorigenic (M2) one in various experimental models. Here, we evaluated the effect of PD98059, a mitogen-activated protein kinase kinase MAPKK MEK1-linked pathway inhibitor, on the differentiation and polarization of THP-1 monocytes in response to phorbol-12-myristate-13-acetate (PMA) under various culture conditions for tumor microenvironmental application. : Differentiation and polarization of THP-1 were analyzed by flow cytometry and RT-PCR. Polarized THP-1 subsets with different treatment were compared by motility, phagocytosis, and so on. : Clearly, PMA induced THP-1 differentiation occurs in adherent culture conditions more than nonadherent culture conditions by increasing CD11b expression up to 90%, which was not affected by PD98059 when cells were exposed to PMA first (post-PD) but inhibited when PD98059 was treated prior to PMA treatment (pre-PD). CD11b THP-1 cells treated with PMA and PMA-post-PD were categorized into M0 (HLA-DR and CD206), M1 (HLA-DR and CD206), and M2 (HLA-DR and CD206), resulting in an increased population of M1 macrophages. The transcription levels of markers of macrophage differentiation and polarization confirmed the increased M1 polarization of THP-1 cells with post-PD treatment rather than with PMA-only treatment. The motility and cytotoxicity of THP-1 cells with post-PD treatment were higher than THP-1 cells with PMA, suggesting that post-PD treatment enhanced the anti-tumorigenicity of THP-1 cells. Confocal microscopy and flow cytometry showed the effect of post-PD treatment on phagocytosis by THP-1 cells. : We have developed an experimental model of macrophage polarization with THP-1 cells which will be useful for further studies related to the tumor microenvironment.
Topics: Humans; Macrophages; Tetradecanoylphorbol Acetate; Flavonoids; THP-1 Cells; Cell Differentiation; Monocytes; Flow Cytometry; Phagocytosis
PubMed: 38929626
DOI: 10.3390/medicina60061009 -
International Journal of Molecular... Jun 2024LPA receptors were expressed in TREx HEK 293 cells, and their signaling and phosphorylation were studied. The agonist, lysophosphatidic acid (LPA), increased...
LPA receptors were expressed in TREx HEK 293 cells, and their signaling and phosphorylation were studied. The agonist, lysophosphatidic acid (LPA), increased intracellular calcium and ERK phosphorylation through pertussis toxin-insensitive processes. Phorbol myristate acetate, but not LPA, desensitizes LPA-mediated calcium signaling, the agonists, and the phorbol ester-induced LPA internalization. Pitstop 2 (clathrin heavy chain inhibitor) markedly reduced LPA-induced receptor internalization; in contrast, phorbol ester-induced internalization was only delayed. LPA induced rapid β-arrestin-LPA receptor association. The agonist and the phorbol ester-induced marked LPA receptor phosphorylation, and phosphorylation sites were detected using mass spectrometry. Phosphorylated residues were detected in the intracellular loop 3 (S221, T224, S225, and S229) and in the carboxyl terminus (S321, S325, S331, T333, S335, Y337, and S343). Interestingly, phosphorylation sites are within sequences predicted to constitute β-arrestin binding sites. These data provide insight into LPA receptor signaling and regulation.
Topics: Humans; Receptors, Lysophosphatidic Acid; Phosphorylation; HEK293 Cells; Signal Transduction; Lysophospholipids; beta-Arrestins; Binding Sites; Calcium Signaling
PubMed: 38928196
DOI: 10.3390/ijms25126491 -
Biomolecules May 2024Nuclear hormone receptors exist in dynamic equilibrium between transcriptionally active and inactive complexes dependent on interactions with ligands, proteins, and...
Nuclear hormone receptors exist in dynamic equilibrium between transcriptionally active and inactive complexes dependent on interactions with ligands, proteins, and chromatin. The present studies examined the hypothesis that endogenous ligands activate peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) in keratinocytes. The phorbol ester treatment or HRAS infection of primary keratinocytes increased fatty acids that were associated with enhanced PPARβ/δ activity. Fatty acids caused PPARβ/δ-dependent increases in chromatin occupancy and the expression of angiopoietin-like protein 4 () mRNA. Analyses demonstrated that stearoyl Co-A desaturase 1 () mediates an increase in intracellular monounsaturated fatty acids in keratinocytes that act as PPARβ/δ ligands. The activation of PPARβ/δ with palmitoleic or oleic acid causes arrest at the G2/M phase of the cell cycle of HRAS-expressing keratinocytes that is not found in similarly treated HRAS-expressing -null keratinocytes. HRAS-expressing -null mouse keratinocytes exhibit enhanced cell proliferation, an effect that is mitigated by treatment with palmitoleic or oleic acid. Consistent with these findings, the ligand activation of PPARβ/δ with GW0742 or oleic acid prevented UVB-induced non-melanoma skin carcinogenesis, an effect that required PPARβ/δ. The results from these studies demonstrate that PPARβ/δ has endogenous roles in keratinocytes and can be activated by lipids found in diet and cellular components.
Topics: Keratinocytes; PPAR-beta; Animals; Mice; Stearoyl-CoA Desaturase; PPAR delta; Fatty Acids; Angiopoietin-Like Protein 4; Humans; Oleic Acid; Proto-Oncogene Proteins p21(ras); Fatty Acids, Monounsaturated; Skin Neoplasms
PubMed: 38927010
DOI: 10.3390/biom14060606 -
Pacing and Clinical Electrophysiology :... Jun 2024To investigate the role of protein kinase C (PKC) in action potential duration (APD) restitution and ventricular tachyarrhythmias (VAs).
OBJECTIVE
To investigate the role of protein kinase C (PKC) in action potential duration (APD) restitution and ventricular tachyarrhythmias (VAs).
METHODS AND RESULTS
Rabbits hearts were isolated and prepared for Langendorff perfusion technique. The stimuli-extra-stimulus (S-S) method and dynamic S pacing protocol were performed to construct APD restitution and to induce APD alternans or VA, respectively, at 10 sites throughout the ventricular chamber. Administration of phorbol-12-myristate-13-acetate (PMA) (100 nM) (n = 15) greatly steepened the restitution curves (S> 1) (p < .01) at each site compared to the control group (n = 15). Furthermore, treatment with PMA also induced larger spatial dispersions of S (p < .05) and decreased the thresholds of the VA and APD alternans (p < .01). However, perfused with the PKC inhibitor, bisindolylmaleimide (BIM) (500 nM) (n = 10), reversibly flattened the APD restitution curves at each site (S< 1), decreased the spatial dispersions of S, and increased the thresholds of APD alternans and VA. According to the results of patch-clamp, peak amplitude of L-type Ca current was significantly increased by addition of PMA compared with control (CTL) group (p < .05). Antagonize this current with verapamil (n = 10) can fully inhibited the PMA induced increasing of S and inducibility of VA and alternans.
CONCLUSION
PKC activation increased the dispersion of APD restitution and thus led to occurrence of VA, which possibly related to the increased Ca influx.
PubMed: 38922937
DOI: 10.1111/pace.14998 -
Critical Care Explorations Jul 2024While cytokine response patterns are pivotal in mediating immune responses, they are also often dysregulated in sepsis and critical illness. We hypothesized that these... (Observational Study)
Observational Study
OBJECTIVES
While cytokine response patterns are pivotal in mediating immune responses, they are also often dysregulated in sepsis and critical illness. We hypothesized that these immunological deficits, quantifiable through ex vivo whole blood stimulation assays, may be indicative of subsequent organ dysfunction.
DESIGN
In a prospective observational study, adult septic patients and critically ill but nonseptic controls were identified within 48 hours of critical illness onset. Using a rapid, ex vivo assay based on responses to lipopolysaccharide (LPS), anti-CD3/anti-CD28 antibodies, and phorbol 12-myristate 13-acetate with ionomycin, cytokine responses to immune stimulants were quantified. The primary outcome was the relationship between early cytokine production and subsequent organ dysfunction, as measured by the Sequential Organ Failure Assessment score on day 3 of illness (SOFAd3).
SETTING
Patients were recruited in an academic medical center and data processing and analysis were done in an academic laboratory setting.
PATIENTS
Ninety-six adult septic and critically ill nonseptic patients were enrolled.
INTERVENTIONS
None.
MEASUREMENTS AND MAIN RESULTS
Elevated levels of tumor necrosis factor and interleukin-6 post-endotoxin challenge were inversely correlated with SOFAd3. Interferon-gamma production per lymphocyte was inversely related to organ dysfunction at day 3 and differed between septic and nonseptic patients. Clustering analysis revealed two distinct immune phenotypes, represented by differential responses to 18 hours of LPS stimulation and 4 hours of anti-CD3/anti-CD28 stimulation.
CONCLUSIONS
Our rapid immune profiling technique offers a promising tool for early prediction and management of organ dysfunction in critically ill patients. This information could be pivotal for early intervention and for preventing irreversible organ damage during the acute phase of critical illness.
Topics: Humans; Prospective Studies; Critical Illness; Sepsis; Male; Female; Middle Aged; Multiple Organ Failure; Aged; Organ Dysfunction Scores; Adult; Cytokines; Cohort Studies; Predictive Value of Tests; Lipopolysaccharides
PubMed: 38916619
DOI: 10.1097/CCE.0000000000001106 -
Chemical Research in Toxicology Jun 2024Peroxymonocarbonate (HCO/HOOCO) is produced by the reversible reaction of CO/HCO with HO ( = 0.33 M, pH 7.0). Although produced in low yields at physiological pHs and HO...
Peroxymonocarbonate (HCO/HOOCO) is produced by the reversible reaction of CO/HCO with HO ( = 0.33 M, pH 7.0). Although produced in low yields at physiological pHs and HO and CO/HCO concentrations, HCO oxidizes most nucleophiles with rate constants 10 to 100 times higher than those of HO. Boronate probes are known examples because HCO reacts with coumarin-7-boronic acid pinacolate ester (CBE) with a rate constant that is approximately 100 times higher than that of HO and the same holds for fluorescein-boronate (Fl-B) as reported here. Therefore, we tested whether boronate probes could provide evidence for HCO formation under biologically relevant conditions. Glucose/glucose oxidase/catalase were adjusted to produce low steady-state HO concentrations (2-18 μM) in Pi buffer at pH 7.4 and 37 °C. Then, CBE (100 μM) was added and fluorescence increase was monitored with time. The results showed that each steady-state HO concentration reacted more rapidly (∼30%) in the presence of CO/HCO (25 mM) than in its absence, and the data permitted the calculation of consistent rate constants. Also, RAW 264.7 macrophages were activated with phorbol 12-myristate 13-acetate (PMA) (1 μg/mL) at pH 7.4 and 37 °C to produce a time-dependent HO concentration (8.0 ± 2.5 μM after 60 min). The media contained 0, 21.6, or 42.2 mM HCO equilibrated with 0, 5, or 10% CO, respectively. In the presence of CBE or Fl-B (30 μM), a time-dependent increase in the fluorescence of the bulk solution was observed, which was higher in the presence of CO/HCO in a concentration-dependent manner. The Fl-B samples were also examined by fluorescence microscopy. Our results demonstrated that mammalian cells produce HCO and boronate probes can evidence and distinguish it from HO under biologically relevant concentrations of HO and CO/HCO.
PubMed: 38916595
DOI: 10.1021/acs.chemrestox.4c00059 -
Burns & Trauma 2024Bacterial infections pose a considerable threat to skin wounds, particularly in the case of challenging-to-treat diabetic wounds. Systemic antibiotics often struggle to...
BACKGROUND
Bacterial infections pose a considerable threat to skin wounds, particularly in the case of challenging-to-treat diabetic wounds. Systemic antibiotics often struggle to penetrate deep wound tissues and topically applied antibiotics may lead to sensitization, necessitating the development of novel approaches for effectively treating germs in deep wound tissues. Neutrophils, the predominant immune cells in the bloodstream, rapidly release an abundance of molecules via degranulation upon activation, which possess the ability to directly eliminate pathogens. This study was designed to develop novel neutrophil cell engineered nanovesicles (NVs) with high production and explore their bactericidal properties and application in promoting infectious wound healing.
METHODS
Neutrophils were isolated from peripheral blood and activated via phorbol myristate acetate (PMA) stimulation. Engineered NVs were prepared by sequentially extruding activated neutrophils followed by ultracentrifugation and were compared with neutrophil-derived exosomes in terms of morphology, size distribution and protein contents. The bactericidal effect of NVs was evaluated using the spread plate technique, LIVE/DEAD backlight bacteria assay and observation of bacterial morphology. The therapeutic effects of NVs were evaluated using wound contraction area measurements, histopathological examinations, assessments of inflammatory factors and immunochemical staining.
RESULTS
Activated neutrophils stimulated with PMA promptly release a substantial amount of bactericidal proteins. NVs are similar to exosomes in terms of morphology and particle size, but they exhibit a significantly higher enrichment of bactericidal proteins. , NVs demonstrated a significant bactericidal effect, presumably mediated by the enrichment of bactericidal proteins such as lysozyme. These NVs significantly accelerated wound healing, leading to a marked reduction in bacterial load, downregulation of inflammatory factors and enhanced collagen deposition in a full-thickness infectious skin defect model.
CONCLUSIONS
We developed engineered NVs derived from activated neutrophils to serve as a novel debridement method targeting bacteria in deep tissues, ultimately promoting infectious wound healing.
PubMed: 38903935
DOI: 10.1093/burnst/tkae018 -
Natural Product Research Jun 2024Two unusual phorbol esters, namely 20-deoxyphorbol-3,4,12-triacetate-13-phenylacetate () and phorbol-3,4,12,13-tetraacetate-20-phenylacetate () plus...
Two unusual phorbol esters, namely 20-deoxyphorbol-3,4,12-triacetate-13-phenylacetate () and phorbol-3,4,12,13-tetraacetate-20-phenylacetate () plus ingol-3,8,12-triacetate-7-phenylacetate () were isolated from the latex of and identified by HRESIMS and 2D NMR. Compound is herein described for the first time. Assignment of the phenylacetyl group at C-7 in compound was suggested by the HMBC and NOESY spectra obtained in pyridine-. In addition to the latex and its distinct terpenoid fractions, the isolated compounds were tested as latent reversal agents against HIV-1-infected J-Lat cells, with reference to phorbol-12-myristate-13-acetate and ingenol-B. Compound reverted 75-80% the viral latency on the GFP-positive cells, resulting EC 3.70 μg/mL (SI 6.7), while induced 34-40% reactivation at the same concentration range (4-20 µg/mL). The ingol derivative was ineffective. Phorbol esters were confirmed as effective constituents in the latex since the fraction containing them was 2.4-fold more active than the lyophilised latex at the lowest concentration assayed.
PubMed: 38902957
DOI: 10.1080/14786419.2024.2364261 -
The Journal of Biological Chemistry Jun 2024The voltage-gated Kv1.5 potassium channel, conducting the ultra-rapid delayed rectifier K current (I) in human cells, plays important roles in the repolarization of...
The voltage-gated Kv1.5 potassium channel, conducting the ultra-rapid delayed rectifier K current (I) in human cells, plays important roles in the repolarization of atrial action potentials and regulation of the vascular tone. We previously reported that activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) induces endocytic degradation of cell-surface Kv1.5 channels, and a point mutation removing the phosphorylation site, T15A, in the N terminus of Kv1.5 abolished the PMA-effect. In the present study, using mutagenesis, patch clamp recording, Western blot analysis and immunocytochemical staining, we demonstrate that ubiquitination is involved in PMA-mediated degradation of mature Kv1.5 channels. Since the expression of Kv1.4 channel is unaffected by PMA treatment, we swapped the N- and/or C-termini between Kv1.5 and Kv1.4. We found that N-terminus alone did not, but both N- and C-termini of Kv1.5 did confer PMA sensitivity to mature Kv1.4 channels, suggesting the involvement of Kv1.5 C-terminus in the channel ubiquitination. Removal of each of the potential ubiquitination residue Lysine at position 536, 565, and 591 by Arginine substitution (K536R, K565R, and K591R) had little effect, but removal of all three Lysine residues with Arginine substitution (3K-R) partially reduced PMA-mediated Kv1.5 degradation. Furthermore, removing the cysteine residue at position 604 by Serine substitution (C604S) drastically reduced PMA-induced channel degradation. Removal of the three Lysines and Cys604 with a quadruple mutation (3K-R/C604S) or a truncation mutation (Δ536) completely abolished the PKC activation-mediated degradation of Kv1.5 channels. These results provide mechanistic insight into PKC activation-mediated Kv1.5 degradation.
PubMed: 38897569
DOI: 10.1016/j.jbc.2024.107483