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Scientific Reports Jun 2024Myocardin-related transcription factors (MRTFs: myocardin/MYOCD, MRTF-A/MRTFA, and MRTF-B/MRTFB) suppress production of pro-inflammatory cytokines and chemokines in...
Myocardin-related transcription factors (MRTFs: myocardin/MYOCD, MRTF-A/MRTFA, and MRTF-B/MRTFB) suppress production of pro-inflammatory cytokines and chemokines in human smooth muscle cells (SMCs) through sequestration of RelA in the NF-κB complex, but additional mechanisms are likely involved. The cGAS-STING pathway is activated by double-stranded DNA in the cytosolic compartment and acts through TANK-binding kinase 1 (TBK1) to spark inflammation. The present study tested if MRTFs suppress inflammation also by targeting cGAS-STING signaling. Interrogation of a transcriptomic dataset where myocardin was overexpressed using a panel of 56 cGAS-STING cytokines showed the panel to be repressed. Moreover, MYOCD, MRTFA, and SRF associated negatively with the panel in human arteries. RT-qPCR in human bronchial SMCs showed that all MRTFs reduced pro-inflammatory cytokines on the panel. MRTFs diminished phosphorylation of TBK1, while STING phosphorylation was marginally affected. The TBK1 inhibitor amlexanox, but not the STING inhibitor H-151, reduced the anti-inflammatory effect of MRTF-A. Co-immunoprecipitation and proximity ligation assays supported binding between MRTF-A and TBK1 in SMCs. MRTFs thus appear to suppress cellular inflammation in part by acting on the kinase TBK1. This may defend SMCs against pro-inflammatory insults in disease.
Topics: Humans; Protein Serine-Threonine Kinases; Nuclear Proteins; Myocytes, Smooth Muscle; Trans-Activators; Inflammation; Signal Transduction; Cytokines; Phosphorylation; Transcription Factors; Membrane Proteins; Cells, Cultured
PubMed: 38858497
DOI: 10.1038/s41598-024-63901-3 -
World Journal of Critical Care Medicine Jun 2024Extracorporeal organ support (ECOS) has made remarkable progress over the last few years. Renal replacement therapy, introduced a few decades ago, was the first...
Extracorporeal organ support (ECOS) has made remarkable progress over the last few years. Renal replacement therapy, introduced a few decades ago, was the first available application of ECOS. The subsequent evolution of ECOS enabled the enhanced support to many other organs, including the heart [veno-arterial extracorporeal membrane oxygenation (ECMO), slow continuous ultrafiltration], the lungs (veno-venous ECMO, extracorporeal carbon dioxide removal), and the liver (blood purification techniques for the detoxification of liver toxins). Moreover, additional indications of these methods, including the suppression of excessive inflammatory response occurring in severe disorders such as sepsis, coronavirus disease 2019, pancreatitis, and trauma (blood purification techniques for the removal of exotoxins, endotoxins, or cytokines), have arisen. Multiple organ support therapy is crucial since a vast majority of critically ill patients present not with a single but with multiple organ failure (MOF), whereas, traditional therapeutic approaches (mechanical ventilation for acute respiratory failure, antibiotics for sepsis, and inotropes for cardiac dysfunction) have reached the maximum efficacy and cannot be improved further. However, several issues remain to be clarified, such as the complexity and cost of ECOS systems, standardization of indications, therapeutic protocols and initiation time, choice of the patients who will benefit most from these interventions, while evidence from randomized controlled trials supporting their use is still limited. Nevertheless, these methods are currently a part of routine clinical practice in intensive care units. This editorial presents the past, present, and future considerations, as well as perspectives regarding these therapies. Our better understanding of these methods, the pathophysiology of MOF, the crosstalk between native organs resulting in MOF, and the crosstalk between native organs and artificial organ support systems when applied sequentially or simultaneously, will lead to the multiplication of their effects and the minimization of complications arising from their use.
PubMed: 38855267
DOI: 10.5492/wjccm.v13.i2.92458 -
Philosophical Transactions of the Royal... Jul 2024Which proportion of the long-term potentiation (LTP) expressed in the bulk of excitatory synapses is postsynaptic and which presynaptic remains debatable. To understand...
Which proportion of the long-term potentiation (LTP) expressed in the bulk of excitatory synapses is postsynaptic and which presynaptic remains debatable. To understand better the possible impact of either LTP form, we explored a realistic model of a CA1 pyramidal cell equipped with known membrane mechanisms and multiple, stochastic excitatory axo-spinous synapses. Our simulations were designed to establish an input-output transfer function, the dependence between the frequency of presynaptic action potentials triggering probabilistic synaptic discharges and the average frequency of postsynaptic spiking. We found that, within the typical physiological range, potentiation of the postsynaptic current results in a greater overall output than an equivalent increase in presynaptic release probability. This difference grows stronger at lower input frequencies and lower release probabilities. Simulations with a non-hierarchical circular network of principal neurons indicated that equal increases in either synaptic fidelity or synaptic strength of individual connections also produce distinct changes in network activity, although the network phenomenology is likely to be complex. These observations should help to interpret the machinery of LTP phenomena documented . This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
Topics: Long-Term Potentiation; Models, Neurological; Synapses; Pyramidal Cells; Animals; Computer Simulation; Action Potentials; CA1 Region, Hippocampal
PubMed: 38853561
DOI: 10.1098/rstb.2023.0235 -
Journal of Translational Medicine Jun 2024Acute myocardial infarction (AMI) is a serious condition that occurs when part of the heart is subjected to ischemia episodes, following partial or complete occlusion of... (Review)
Review
Acute myocardial infarction (AMI) is a serious condition that occurs when part of the heart is subjected to ischemia episodes, following partial or complete occlusion of the epicardial coronary arteries. The resulting damage to heart muscle cells have a significant impact on patient's health and quality of life. About that, recent research focused on the role of the sarcoplasmic reticulum (SR) and mitochondria in the physiopathology of AMI. Moreover, SR and mitochondria get in touch each other through multiple membrane contact sites giving rise to the subcellular region called mitochondria-associated membranes (MAMs). MAMs are essential for, but not limited to, bioenergetics and cell fate. Disruption of the architecture of these regions occurs during AMI although it is still unclear the cause-consequence connection and a complete overview of the pathological changes; for sure this concurs to further damage to heart muscle. The calcium ion (Ca) plays a pivotal role in the pathophysiology of AMI and its dynamic signaling between the SR and mitochondria holds significant importance. In this review, we tried to summarize and update the knowledge about the roles of these organelles in AMI from a Ca signaling point of view. Accordingly, we also reported some possible cardioprotective targets which are directly or indirectly related at limiting the dysfunctions caused by the deregulation of the Ca signaling.
Topics: Humans; Myocardial Infarction; Sarcoplasmic Reticulum; Calcium Signaling; Animals; Mitochondria; Calcium
PubMed: 38853272
DOI: 10.1186/s12967-024-05240-5 -
Communications Biology Jun 2024Selective serotonin reuptake inhibitors (SSRIs) are widely used for depression based on the monoamine deficiency hypothesis. However, the clinical use of these agents is...
Selective serotonin reuptake inhibitors (SSRIs) are widely used for depression based on the monoamine deficiency hypothesis. However, the clinical use of these agents is controversial, in part because of their variable clinical efficacy and in part because of their delayed onset of action. Because of the complexities involved in replicating human disease and clinical dosing in animal models, the scientific community has not reached a consensus on the reasons for these phenomena. In this work, we create a theoretical hippocampal model incorporating escitalopram's pharmacokinetics, pharmacodynamics (competitive and non-competitive inhibition, and serotonin transporter (SERT) internalization), inflammation, and receptor dynamics. With this model, we simulate chronic oral escitalopram in mice showing that days to weeks are needed for serotonin levels to reach steady-state. We show escitalopram's chemical efficacy is diminished under inflammation. Our model thus offers mechanisms for how chronic escitalopram affects brain serotonin, emphasizing the importance of optimized dose and time for future antidepressant discoveries.
Topics: Serotonin Plasma Membrane Transport Proteins; Animals; Selective Serotonin Reuptake Inhibitors; Mice; Inflammation; Escitalopram; Hippocampus; Serotonin; Humans; Citalopram
PubMed: 38851804
DOI: 10.1038/s42003-024-06240-3 -
Molecular & Cellular Proteomics : MCP Jun 2024Protein O-linked mannose (O-Man) glycosylation is an evolutionary conserved post-translational modification (PTM) that fulfills important biological roles during...
Protein O-linked mannose (O-Man) glycosylation is an evolutionary conserved post-translational modification (PTM) that fulfills important biological roles during embryonic development. Three non-redundant enzyme families, POMT1/POMT2, TMTC1-4 and TMEM260, selectively coordinate the initiation of protein O-Man glycosylation on distinct classes of transmembrane proteins, including α-dystroglycan, cadherins and plexin receptors. However, a systematic investigation of their substrate specificities is lacking, in part due to the ubiquitous expression of O-Man glycosyltransferases in cells, which precludes analysis of pathway-specific O-Man glycosylation on a proteome-wide scale. Here, we apply a targeted workflow for membrane glycoproteomics across five human cell lines to extensively map O-Man substrates and genetically deconstruct O-Man initiation by individual and combinatorial knock-out (KO) of O-Man glycosyltransferase genes. We established a human cell library for analysis of substrate specificities of individual O-Man initiation pathways by quantitative glycoproteomics. Our results identify 180 O-Man glycoproteins, demonstrate new protein targets for the POMT1/POMT2 pathway and show that TMTC1-4 and TMEM260 pathways widely target distinct Ig-like protein domains of plasma membrane proteins involved in cell-cell and cell-extracellular matrix interactions. The identification of O-Man on Ig-like folds adds further knowledge on the emerging concept of domain-specific O-Man glycosylation which opens for functional studies of O-Man glycosylated adhesion molecules and receptors.
PubMed: 38851451
DOI: 10.1016/j.mcpro.2024.100796 -
Biomedicine & Pharmacotherapy =... Jul 2024Multiple myeloma (MM) progression is closely dependent on cells in the bone marrow (BM) microenvironment, including fibroblasts (FBs) and immune cells. In their BM...
Multiple myeloma (MM) progression is closely dependent on cells in the bone marrow (BM) microenvironment, including fibroblasts (FBs) and immune cells. In their BM niche, MM cells adhere to FBs sustaining immune evasion, drug resistance and the undetectable endurance of tumor cells known as minimal residual disease (MRD). Here, we describe the novel bi-specific designed ankyrin repeat protein (DARPin) α-FAPx4-1BB (MP0310) with FAP-dependent 4-1BB agonistic activity. The α-FAPx4-1BB DARPin simultaneously binds to FAP and 4-1BB overexpressed by activated FBs and immune cells, respectively. Although flow cytometry analysis showed that T and NK cells from MM patients were not activated and did not express 4-1BB, stimulation with daratumumab or elotuzumab, monoclonal antibodies (mAbs) currently used for the treatment of MM, significantly upregulated 4-1BB both in vitro and in MM patients following mAb-based therapy. The mAb-induced 4-1BB overexpression allowed the engagement of α-FAPx4-1BB that acted as a bridge between FAPFBs and 4-1BBNK cells. Therefore, α-FAPx4-1BB enhanced both the adhesion of daratumumab-treated NK cells on FBs as well as their activation by improving release of CD107a and perforin, hence MM cell killing via antibody-mediated cell cytotoxicity (ADCC). Interestingly, α-FAPx4-1BB significantly potentiated daratumumab-mediated ADCC in the presence of FBs, suggesting that it may overcome the BM FBs' immunosuppressive effect. Overall, we speculate that treatment with α-FAPx4-1BB may represent a valuable strategy to improve mAb-induced NK cell activity fostering MRD negativity in MM patients through the eradication of latent MRD cells.
Topics: Killer Cells, Natural; Multiple Myeloma; Humans; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal; Cell Line, Tumor; Tumor Necrosis Factor Receptor Superfamily, Member 9; Membrane Proteins; Endopeptidases
PubMed: 38850654
DOI: 10.1016/j.biopha.2024.116877 -
The Journal of Physical Chemistry. B Jun 2024Particulate MMO (pMMO) catalyzes the oxidation of methane to methanol and also ammonia to hydroxylamine. Experimental characterization of the active site has been very...
Particulate MMO (pMMO) catalyzes the oxidation of methane to methanol and also ammonia to hydroxylamine. Experimental characterization of the active site has been very difficult partly because the enzyme is membrane-bound. However, recently, there has been major progress mainly through the use of cryogenic electron microscopy (cryoEM). Electron paramagnetic resonance (EPR) and X-ray spectroscopy have also been employed. Surprisingly, the active site has only one copper. There are two histidine ligands and one asparagine ligand, and the active site is surrounded by phenyl alanines but no charged amino acids in the close surrounding. The present study is the first quantum chemical study using a model of that active site (Cu). Low barrier mechanisms have been found, where an important part is that there are two initial proton-coupled electron transfer steps to a bound O ligand before the substrate enters. Surprisingly, this leads to large radical character for the oxygens even though they are protonated. That result is very important for the ability to accept a proton from the substrates. Methods have been used which have been thoroughly tested for redox enzyme mechanisms.
Topics: Oxidation-Reduction; Methane; Oxygenases; Ammonia; Catalytic Domain; Models, Molecular; Electron Spin Resonance Spectroscopy
PubMed: 38850249
DOI: 10.1021/acs.jpcb.4c01807 -
BMC Plant Biology Jun 2024The phosphorylation of the Light-Harvesting Complex of photosystem II (LHCII) driven by STATE TRANSITION 7 (STN7) kinase is a part of one of the crucial regulatory...
BACKGROUND
The phosphorylation of the Light-Harvesting Complex of photosystem II (LHCII) driven by STATE TRANSITION 7 (STN7) kinase is a part of one of the crucial regulatory mechanisms of photosynthetic light reactions operating in fluctuating environmental conditions, light in particular. There are evidenced that STN7 can also be activated without light as well as in dark-chilling conditions. However, the biochemical mechanism standing behind this complex metabolic pathway has not been deciphered yet.
RESULTS
In this work, we showed that dark-chilling induces light-independent LHCII phosphorylation in runner bean (Phaseolus coccineus L.). In dark-chilling conditions, we registered an increased reduction of the PQ pool which led to activation of STN7 kinase, subsequent LHCII phosphorylation, and possible LHCII relocation inside the thylakoid membrane. We also presented the formation of a complex composed of phosphorylated LHCII and photosystem I typically formed upon light-induced phosphorylation. Moreover, we indicated that the observed steps were preceded by the activation of the oxidative pentose phosphate pathway (OPPP) enzymes and starch accumulation.
CONCLUSIONS
Our results suggest a direct connection between photosynthetic complexes reorganization and dark-chilling-induced activation of the thioredoxin system. The proposed possible pathway starts from the activation of OPPP enzymes and further NADPH-dependent thioredoxin reductase C (NTRC) activation. In the next steps, NTRC simultaneously activates ADP-glucose pyrophosphorylase and thylakoid membrane-located NAD(P)H dehydrogenase-like complex. These results in starch synthesis and electron transfer to the plastoquinone (PQ) pool, respectively. Reduced PQ pool activates STN7 kinase which phosphorylates LHCII. In this work, we present a new perspective on the mechanisms involving photosynthetic complexes while efficiently operating in the darkness. Although we describe the studied pathway in detail, taking into account also the time course of the following steps, the biological significance of this phenomenon remains puzzling.
Topics: Phaseolus; Phosphorylation; Light; Thylakoids; Photosystem I Protein Complex; Cold Temperature; Light-Harvesting Protein Complexes; Photosystem II Protein Complex; Plant Proteins; Starch; Pentose Phosphate Pathway; Enzyme Activation; Photosynthesis; Stress, Physiological; Protein Serine-Threonine Kinases
PubMed: 38849759
DOI: 10.1186/s12870-024-05169-3