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Long non-coding RNAs (lncRNA) and circular RNAs (circRNA) that sponge miRNAs could indirectly regulate gene expression, contributing to certain biological processes. This study aimed to investigate the role of non-coding RNAs in the pathogenesis of myocardial ischemia reperfusion-injury (MIRI). MIRI in male C57B/6J mice was induced by left anterior descending coronary artery ligation occlusion for 30 min, and 4 h of reperfusion. RNA sequencing was performed to obtain the mRNA and non-coding RNA expression profiles of the MIRI and sham groups. Bioinformatic methods were used to analyze the co-expression RNAs, miRNA binding sites and competitive endogenous RNA (ceRNA) pairs. Differentially expressed RNAs were identified with a cutoff fold change > 2 and p < 0.05. A total of 64 mRNAs were upregulated and 98 mRNAs were downregulated, and 10 lncRNAs were upregulated and 10 lncRNAs were downregulated. All altered (p < 0.05) mRNAs were selected for gene ontology and pathway analysis. The AMP-activated protein kinase (AMPK) signaling pathway was enriched in the downregulated genes, and the activation of AMPK was confirmed by western blotting. The lncRNA co-expression network and ceRNA network base on genes in AMPK signaling pathway were then constructed, revealing that ENSMUST00000147762.7 and TUCP_000184 might be key regulators in MIRI induced AMPK activation. The expression levels of AMPK signaling-related RNAs and those involved in the ceRNA network were validated using qRT-PCR. Overall, this study identified potential new targets on AMPK signaling in MIRI. • Differential expressed RNAs were identified in MIRI mice compared to sham group. • AMPK signaling pathway is enriched and AMPK was activated in MIRI mice heart. • CeRNA network based on AMPK signaling pathway related mRNAs was constructed. [ABSTRACT FROM AUTHOR]

Drought is a severe and complex abiotic stress that negatively affects plant growth and crop yields. Numerous genes with various functions are induced in response to drought stress to acquire drought stress tolerance. The phytohormone abscisic acid (ABA) accumulates mainly in the leaves in response to drought stress and then activates subclass III SNF1-related protein kinases 2 (SnRK2s), which are key phosphoregulators of ABA signaling. ABA mediates a wide variety of gene expression processes through stress-responsive transcription factors, including ABA-RESPONSIVE ELEMENT BINDING PROTEINS (AREBs)/ABRE-BINDING FACTORS (ABFs) and several other transcription factors. Seed plants have another type of SnRK2s, ABA-unresponsive subclass I SnRK2s, that mediates the stability of gene expression through the mRNA decay pathway and plant growth under drought stress in an ABA-independent manner. Recent research has elucidated the upstream regulators of SnRK2s, RAF-like protein kinases, involved in early responses to drought stress. ABA-independent transcriptional regulatory systems and ABA-responsive regulation function in drought-responsive gene expression. DEHYDRATION RESPONSIVE ELEMENT (DRE) is an important cis-acting element in ABA-independent transcription, whereas ABA-RESPONSIVE ELEMENT (ABRE) cis-acting element functions in ABA-responsive transcription. In this review article, we summarize recent advances in research on cellular and molecular drought stress responses and focus on phosphorylation signaling and transcription networks in Arabidopsis and crops. We also highlight gene networks of transcriptional regulation through two major regulatory pathways, ABA-dependent and ABA-independent pathways, that ABA-responsive subclass III SnRK2s and ABA-unresponsive subclass I SnRK2s mediate, respectively. We also discuss crosstalk in these regulatory systems under drought stress.

This Special Issue of The FEBS Journal brings together a set of review articles focused on recent developments in the field of GPCR biology, with particular emphasis on novel paradigms of their activation, signaling, and regulation. These articles cover a broad repertoire of cellular, physiological, and structural aspects ranging from the interaction of GPCRs with their signal transducers, allosteric modulation of these receptors with therapeutic implications, and emerging technologies aimed to probe critical aspects of receptor signaling and regulation. [ABSTRACT FROM AUTHOR]

Inositol phospholipids play an important role in cell physiology. The inositol head groups are reversibly phosphorylated to produce seven distinct phosphorylated inositides, commonly referred to as phosphoinositides (PIs). These seven PIs are dynamically interconverted from one PI to another by the action of PI kinases and PI phosphatases. The PI signals regulate a wide variety of cellular functions, including organelle distinction, vesicular transport, cytoskeletal organization, nuclear events, regulation of ion channels, cell signaling, and host–pathogen interactions. Most of the studies of PIs in ocular tissues are based on the PI enzymes and PI phosphatases. In this study, we examined the PI levels in the cornea, retinal pigment epithelium (RPE), and retina using PI-binding protein as probes. We have examined the lipids PI(3)P, PI(4)P, PI(3,4)P2, PI(4,5)P2, and PI(3,4,5)P3, and each is present in the cornea, RPE, and retina. Alterations in the levels of these PIs in mouse models of retinal disease and corneal infections have been reported, and the results of our study will help in the management of anomalous phosphoinositide metabolism in ocular tissues.

Signaling by the G-protein-coupled receptors (GPCRs) plays fundamental role in a vast number of essential physiological functions. Precise control of GPCR signaling requires action of regulators of G protein signaling (RGS) proteins that deactivate heterotrimeric G proteins. RGS proteins are elaborately regulated and comprise multiple domains and subunits, yet structural organization of these assemblies is poorly understood. Here, we report a crystal structure and dynamics analyses of the multisubunit complex of RGS7, a major regulator of neuronal signaling with key roles in controlling a number of drug target GPCRs and links to neuropsychiatric disease, metabolism, and cancer. The crystal structure in combination with molecular dynamics and mass spectrometry analyses reveals unique organizational features of the complex and long-range conformational changes imposed by its constituent subunits during allosteric modulation. Notably, several intermolecular interfaces in the complex work in synergy to provide coordinated modulation of this key GPCR regulator.

Cells experience time-varying and spatially heterogeneous chemokine signals in vivo , activating cell surface proteins including G protein-coupled receptors (GPCRs). The Gαq pathway activation by GPCRs is a major signaling axis with broad physiological and pathological significance. Compared with other Gα members, GαqGTP activates many crucial effectors, including PLCβ (Phospholipase Cβ) and Rho GEFs (Rho guanine nucleotide exchange factors). PLCβ regulates many key processes, such as hematopoiesis, synaptogenesis, and cell cycle, and is therefore implicated in terminal-debilitating diseases, including cancer, epilepsy, Huntington's Disease, and Alzheimer's Disease. However, due to a lack of genetic and pharmacological tools, examining how the dynamic regulation of PLCβ signaling controls cellular physiology has been difficult. Since activated PLCβ induces several abrupt cellular changes, including cell morphology, examining how the other pathways downstream of Gq-GPCRs contribute to the overall signaling has also been difficult. Here we show the engineering, validation, and application of a highly selective and efficient optogenetic inhibitor (Opto-dHTH) to completely disrupt GαqGTP-PLCβ interactions reversibly in user-defined cellular-subcellular regions on optical command. Using this newly gained PLCβ signaling control, our data indicate that the molecular competition between RhoGEFs and PLCβ for GαqGTP determines the potency of Gq-GPCR-governed directional cell migration.

Cells rely on secreted signaling molecules to coordinate essential biological functions including development, metabolism, and immunity. Unfortunately, such signaling processes remain difficult to measure with sufficient chemical specificity and temporal resolution. To address this need, an aptamer-conjugated hydrogel matrix that enables continuous fluorescent measurement of specific secreted analytes - in two dimensions, in real-time is developed. As a proof of concept, real-time imaging of inter-cellular cyclic adenosine 3',5'-monophosphate (cAMP) signals in Dictyostelium discoideum amoeba cells is performed. A set of aptamer switches that generate a rapid and reversible change in fluorescence in response to cAMP signals is engineered. By combining multiple switches with different dynamic ranges, measure cAMP concentrations spanning three orders of magnitude in a single experiment can be measured. These sensors are embedded within a biocompatible hydrogel on which cells are cultured and their cAMP secretions can be imaged using fluorescent microscopy. Using this aptamer-hydrogel material system, the first direct measurements of oscillatory cAMP signaling that correlate closely with previous indirect measurements are achieved. Using different aptamer switches, this approach can be generalized for measuring other secreted molecules to directly visualize diverse extracellular signaling processes and the biological effects that they trigger in recipient cells., (© 2023 Wiley-VCH GmbH.)

Introduction: Exosomes, a subset of extracellular vesicles (EVs), are crucial for intercellular communication in various contexts. Despite their small size, they carry diverse cargo, including RNA, proteins, and lipids. Internalization by recipient cells raises concerns about potential disruptions to cellular functions. Notably, the ability of exosomes to traverse the blood-brain barrier (BBB) has significant implications., Methods: To conduct a thorough investigation into the existing academic literature on exosomes within the framework of neuron-glia communication, a comprehensive search strategy was implemented across the PubMed, Google Scholar, and Science Direct databases. Multiple iterations of the keywords "exosome," "neuron-glia communication," and "neurological disorders" were employed to systematically identify relevant publications. Furthermore, an exploration of the Clinicaltrials.gov database was undertaken to identify clinical trials related to cellular signaling, utilizing analogous terminology., Results: Although the immediate practical applications of exosomes are somewhat limited, their potential as carriers of pathogenic attributes offers promising opportunities for the development of precisely targeted therapeutic strategies for neurological disorders. This review presents a comprehensive overview of contemporary insights into the pivotal roles played by exosomes as agents mediating communication between neurons and glial cells within the central nervous system (CNS)., Conclusion: By delving into the intricate dynamics of exosomal communication in the CNS, this review contributes to a deeper understanding of the roles of exosomes in both physiological and pathological processes, thereby paving the way for potential therapeutic advancements in the field of neurological disorders., Competing Interests: The authors have no relevant financial or nonfinancial interests to disclose., (© 2024 The Author(s).)

Largely due to its simplicity, while being more like human cells compared to other experimental models, Dictyostelium continues to be of great use to discover basic molecular mechanisms and signaling pathways underlying evolutionarily conserved biological processes. However, the identification of new protein interactions implicated in signaling pathways can be particularly challenging in Dictyostelium due to its extremely fast signaling kinetics coupled with the dynamic nature of signaling protein interactions. Recently, the proximity labeling method using engineered ascorbic acid peroxidase 2 (APEX2) in mammalian cells was shown to allow the detection of weak and/or transient protein interactions and also to obtain spatial and temporal resolution. Here, we describe a protocol for successfully using the APEX2-proximity labeling method in Dictyostelium. Coupled with the identification of the labeled proteins by mass spectrometry, this method expands Dictyostelium's proteomics toolbox and should be widely useful for identifying interacting partners involved in a variety of biological processes in Dictyostelium., (© 2024. The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

The current pandemic of coronavirus disease (COVID-19) caused by SARS-CoV-2 is a significant global health challenge. A recent study by Carvelli and colleagues now demonstrates the involvement of complement C5a and its receptor C5aR1 in disease progression and suggests that blockade of the C5a-C5aR1 axis may represent a potential therapeutic strategy against COVID-19. [ABSTRACT FROM AUTHOR]

Abstract Mitogen‐activated protein kinases (MAPK) are broadly used regulators of cellular signaling. However, how these enzymes can be involved in such a broad spectrum of physiological functions is not understood. Systematic discovery of MAPK networks both experimentally and in silico has been hindered because MAPKs bind to other proteins with low affinity and mostly in less‐characterized disordered regions. We used a structurally consistent model on kinase‐docking motif interactions to facilitate the discovery of short functional sites in the structurally flexible and functionally under‐explored part of the human proteome and applied experimental tools specifically tailored to detect low‐affinity protein–protein interactions for their validation in vitro and in cell‐based assays. The combined computational and experimental approach enabled the identification of many novel MAPK‐docking motifs that were elusive for other large‐scale protein–protein interaction screens. The analysis produced an extensive list of independently evolved linear binding motifs from a functionally diverse set of proteins. These all target, with characteristic binding specificity, an ancient protein interaction surface on evolutionarily related but physiologically clearly distinct three MAPKs (JNK, ERK, and p38). This inventory of human protein kinase binding sites was compared with that of other organisms to examine how kinase‐mediated partnerships evolved over time. The analysis suggests that most human MAPK‐binding motifs are surprisingly new evolutionarily inventions and newly found links highlight (previously hidden) roles of MAPKs. We propose that short MAPK‐binding stretches are created in disordered protein segments through a variety of ways and they represent a major resource for ancient signaling enzymes to acquire new regulatory roles.

Ether-lipids (EL) are specific lipids bearing a characteristic sn-1 ether bond. Depending on the ether or vinyl-ether nature of this bond, they are present as alkyl- or alkenyl-EL, respectively. Among EL, alkenyl-EL, also referred as plasmalogens in the literature, attract most of the scientific interest as they are the predominant EL species in eukaryotic cells, thus less is known about alkyl-EL. EL have been implicated in various signaling pathways and alterations in their quantity are frequently observed in pathologies such as neurodegenerative and cardiovascular diseases or cancer. However, it remains unknown whether both alkyl- and alkenyl-EL play the same roles in these processes. This review summarizes the roles and mechanisms of action of EL in cellular signaling and tries to discriminate between alkyl- and alkenyl-EL. We also focus on the involvement of EL-mediated alterations of cellular signaling in diseases and discuss the potential interest for EL in therapy., (Copyright © 2023 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

The endoplasmic reticulum (ER) stress and inflammation relations hip occurs at different levels and is essential for the adequate homeostatic function of cellular systems, becoming harmful when chronically engaged. Intense physical exercise enhances serum levels of interleukin 6 (IL-6). In response to a chronic exhaustive physical exercise protocol, our research group verified an increase of the IL-6 co ncentration and ER stress proteins in extensor digitorium longus (EDL) and soleus. Based on these results, we hypothesized that IL-6-knockout mice would demonstrate a lower modulation in the ER stress proteins compared to the wild-type mice. To clarify the relationship between exercise-induced IL-6 increased and ER stress, we studied the e ffects of an acute exhaustive physical exercise protocol on the levels of ER stress proteins in the skeletal muscles of IL-6-knockout (KO) mice. The WT group displayed a higher exhaustion time compared to the IL-6 KO group. After 1 h of the acute exercise protocol, the serum levels of IL-6 and IL-10 were enhanced in the WT group. Independent of the experimental group, the CHOP and cleaved caspase 12/total caspase 12 ratio in EDL as well as ATF6 and CHOP in soleus were sensitive to the acute exercise protocol. Compared to the WT group, the oscillation patterns over time of BiP in EDL and soleus as well as of peIF2-alpha/eIF2-alpha ratio in soleus were attenuated for the IL-6 KO group. In conclusion, IL-6 seems to be related with the ER stress homeostasis, once knockout mice presented attenuation of BiP in EDL and soleus as well as of pEiF2-alpha/EiF2-alpha ratio in soleus after the acute exhaustive physical exercise protocol. [ABSTRACT FROM AUTHOR]

Abstract Heparan sulfate proteoglycans (HSPG) are macromolecular glyco-conjugates expressed ubiquitously on the cell surface and in the extracellular matrix where they interact with a wide range of ligands to regulate many aspects of cellular function. The capacity of the side glycosaminoglycan chain heparan sulfate (HS) being able to interact with diverse protein ligands relies on its complex structure that is generated by a controlled biosynthesis process, involving the actions of glycosyl-transferases, sulfotransferases and the glucuronyl C5-epimerase. It is believed that activities of the modification enzymes control the HS structures that are designed to serve the biological functions in a given cell or biological status. In this review, we briefly discuss recent understandings on the roles of HSPG in cytokine stimulated cellular signaling, focusing on FGF, TGF-β, Wnt, Hh, HGF and VEGF. Highlights • Heparan sulfate proteoglycans play important roles in cytokine stimulated cell signalling • The complicated structure of heparan sulfate enables it interacting with diverse cytokines and their receptors • Heparin may interfere the functions of heparan sulfate [ABSTRACT FROM AUTHOR]

Abstract Protein activation and deactivation is central to a variety of biological mechanisms, including cellular signaling and transport. Unimolecular fluorescent resonance energy transfer (FRET) probes are a class of fusion protein sensors that allow biologists to visualize using an optical microscope whether specific proteins are activated due to the presence nearby of small drug-like signaling molecules, ligands or analytes. Often such probes comprise a donor fluorescent protein attached to a ligand binding domain, a sensor or reporter domain attached to the acceptor fluorescent protein, with these ligand binding and sensor domains connected by a protein linker. Various choices of linker type are possible ranging from highly flexible proteins to hinge-like proteins. It is also possible to select donor and acceptor pairs according to their corresponding Föster radius, or even to mutate binding and sensor domains so as to change their binding energy in the activated or inactivated states. The focus of the present work is the exploration through simulation of the impact of such choices on sensor performance. [ABSTRACT FROM AUTHOR]

Asthma affects ~300 million people worldwide. Despite multiple treatment options, asthma treatment remains unsatisfactory in a subset of patients. Airway obstruction is a hallmark of allergic asthma and is largely due to airway smooth muscle hypercontractility induced by airway inflammation. Identification of molecular pathways that regulate airway smooth muscle hypercontractility is of considerable therapeutic interest. We previously identified roles for milk fat globule epidermal growth factor-like 8 (Mfge8) in opposing the effects of allergic inflammation on increasing airway smooth muscle contractile force. In this study, we delineate the signaling pathway by which Mfge8 mediates these effects. By using genetic and pharmacologic approaches, we show that the α8β1 integrin and the phosphatase and tensin homolog (PTEN) mediate the effects of Mfge8 on preventing IL-13-induced increases in airway contractility. Tracheal rings from mice with smooth muscle-specific deletion of α8β1 or PTEN have enhanced contraction in response to treatment with IL-13. Enhanced IL-13-induced tracheal ring contraction in Mfge8-/- mice was abolished by treatment with the PI3K inhibitor. Mechanistically, IL-13 induces ubiquitination and degradation of PTEN protein. Our findings identify a role for the Mfge8-α8β1-PTEN pathway in regulating the force of airway smooth muscle contraction in the setting of allergic inflammation. [ABSTRACT FROM AUTHOR]

Abstract Metallic nanomaterials are utilized in an increasing number of applications in medicine and industry. Their general toxicity was tested in numerous reports both in vitro and in vivo but limited data exist on how nanomaterials affect the activity of cellular signaling pathways activated by growth factors and cytokines. The aim of the present work was to test the hypothesis predicting that silver, gold and superparamagnetic iron oxide nanoparticles may interfere with cellular signaling activated by tumor necrosis factor (TNF) and change the final cellular outcome of TNF action. Such interference may result in disruption of homeostasis and contribute to the development of malignancies such as cancer or autoimmune diseases. Experiments were performed on HepG2 and A549 cell lines. We did not observe any interaction between nanoparticles and TNF at the level of clonogenic growth, apoptosis/necrosis induction or cell cycle. At all these endpoints, the effects of TNF and nanoparticles were additive. In contrast, gene expression analysis revealed synergistic effects. A group of genes was significantly affected only by simultaneous treatment with TNF and nanoparticles and not by any of the factors alone. Observed synergistic effect on IL10 and IL8 expression seems to be of particular importance since these cytokines are often expressed by tumor cells to inhibit tumor-targeted immune response. The observed synergistic effects of TNF and nanoparticles on cytokines expression may have significant consequences for tissue homeostasis and tumor promotion and therefore should be taken into account during development of new nanoparticle-based anticancer therapies. Highlights • Nanoparticles can significantly modify response to TNF at transcriptional level. • AgNPs have synergistic effect on IL8 secretion by HepG2 cells after TNF treatment. • No interaction between NPs and TNF at the level of clonogenic growth. • No interaction between NPs and TNF at the level of apoptosis induction or cell cycle. [ABSTRACT FROM AUTHOR]

Numerous studies have demonstrated that Gram-positive microbiomes play an important role in the pathogenesis and in the way of treatment of chronic rhinosinusitis (CRS). Kinins are inflammatory mediators and one of their receptors, namely bradykinin receptor 1 (BKR1 or B1R), is believed to be induced and involved in inflammation in pathophysiological conditions. In the present study, we investigated the effect of peptidoglycan (PGN), a major cell wall component of G(+) bacteria, on BKR expression and its signaling pathway in nasal fibroblasts from CRS without nasal polyp (CRSsNP). The PGN induced increases in B1R mRNA and protein production. The induction was abolished by the NF-κB and protein kinase A inhibitor. In parallel, the PGN treatment directly activated IκB/NF-κB signaling and CREB phosphorylation. Interestingly, a further analysis suggested no involvement of cAMP/PKA/CREB pathway in this induction. The B1R expression and IκB/NF-κB signaling pathway could be attenuated by Toll-like receptor-2 (TLR2) blocking/neutralizing Ab. In a functional assay, the addition of B1R selective agonist (Des-Arg10-kallidin) to the fibroblasts after PGN stimulation led to an increase in CXCL8 release and p38 MAPK and ERK1/2 phosphorylation, which could be inhibited by the B1R antagonist. Taken together, our results revealed for the first time that PGN can increase B1R expression in human nasal mucosa-derived fibroblasts through TLR2 activation and NF-κB signaling pathway. This induction functionally leads to MAPKs activation and CXCL8 release upon B1R stimulation. Our results also suggest that a major component of G(+) bacteria can participate in B1R upregulation in nasal mucosa during CRSsNP progression. [ABSTRACT FROM AUTHOR]

Many metabolic processes that occur in living cells involve oxidation-reduction (redox) chemistry underpinned by compounds, such as glutathione, ascorbate, and/or pyridine nucleotides. Among these redox carriers, nicotinamide adenine dinucleotide (NAD+) represents one of the cornerstones of cellular oxidation and is essential for plant growth and development. In addition to its redox role, compelling evidence of a role for NAD+ as a signal molecule in plants is emerging. In non-plant systems, NAD+ biosynthesis can be the product of two independent pathways—the de novo and the salvage pathway. Despite the fact that homologous plant genes exist for the composite enzymes of most, if not all, of these pathways research into plant NAD+ biosynthesis per se has lagged behind that of microbial and mammalian systems. Indeed, much plant work has been focused on additional roles of the composite enzymes in processes, such as DNA repair or post-translational modification of proteins. That said, in recent years, a number of studies, mostly in Arabidopsis, have been carried out in order to fill this knowledge gap. Therefore, in this review, we intend to present a synthesis of such molecular genetic studies as well as biochemical analyses that have begun to elucidate the regulatory hierarchies both of NAD+ biosynthesis and the parallel activities of the enzymes that are involved in these pathways. [ABSTRACT FROM AUTHOR]

The development of network inference methodologies that accurately predict connectivity in dysregulated pathways may enable the rational selection of patient therapies. Accurately inferring an intracellular network from data remains a very challenging problem in molecular systems biology. Living cells integrate extremely robust circuits that exhibit significant heterogeneity, but still respond to external stimuli in predictable ways. This phenomenon allows us to introduce a network inference methodology that integrates measurements of protein activation from perturbation experiments. The methodology relies on logic-based networks to provide a predictive approximation of the transfer of signals in a network. The approach presented was validated in silico with a set of test networks and applied to investigate the epidermal growth factor receptor signaling of a breast epithelial cell line, MFC10A. In our analysis, we predict the potential signaling circuitry most likely responsible for the experimental readouts of several proteins in the mitogen-activated protein kinase and phosphatidylinositol-3 kinase pathways. The approach can also be used to identify additional necessary perturbation experiments to distinguish between a set of possible candidate networks. [ABSTRACT FROM AUTHOR]

Abstract: Amalgamation of delivery and tracking of therapeutically relevant moieties on a single platform is made possible by the application of metal nanoclusters, an innovative class of luminescent nanomaterials. Metal nanoclusters, possessing molecule‐like attributes, display extraordinary size and shape tunable properties befitting theranostic applications. Herein, we report successful assembly of therapeutically significant phosphatase protein PTEN and fluorescent lysozyme‐stabilized silver nanoclusters to accomplish delivery and tracking of the protein. Down‐regulation of PTEN perturbs the cellular networking leading to copious pathological conditions. The integration of purified recombinant PTEN with silver nanoclusters was evaluated by fluorescence spectroscopy study. A key feature of this study is the use of polyethylene glycol coating that allows fabrication of the assembly into spherical nanocomposites as characterized by transmission electron microscope along with retention of both optical functionality of the cluster and biological activity of the protein. Prior to cellular application, the functional integrity of PTEN in the composite was determined in vitro, by enzymatic assay employing para‐nitrophenylphosphate as substrate. Cellular internalization of the cargo was studied by confocal microscopy and flow cytometry analysis. The efficacy of the payload on modulation of cellular signaling was assessed on cell lines that expressed PTEN differentially. PTEN null U‐87 MG and PTEN expressing MCF7 cell lines displayed successful alteration of AKT and FAK signaling proteins culminating in cell cycle arrest and reduced wound healing capacity. A dose dependent reduction in cell proliferation of MCF7 cells was achieved. For U‐87 MG, treatment with the payload resulted in chemosensitization toward anti‐cancer drug erlotinib. Thus, PEG coated GST‐PTEN loaded silver nanoclusters serves as a comprehensive system encompassing cellular imaging and protein delivery with potential biomedical implications. [ABSTRACT FROM AUTHOR]

The article discusses the role of epidermal growth factor receptor (EGFR) pathway substrate 8 (EPS8) as treatment for patient with oral cancer. It mentions that EPS8 influence a range of normal biological processes such as trafficking of the EGFR, regulation of actin dynamics and cellular proliferation.

CD99 is a cell surface protein with unique features and only partly defined mechanisms of action. This molecule is involved in crucial biological processes, including cell adhesion, migration, death, differentiation and diapedesis, and it influences processes associated with inflammation, immune responses and cancer. CD99 is frequently overexpressed in many types of tumors, particularly pediatric tumors including Ewing sarcoma and specific subtypes of leukemia. Engagement of CD99 induces the death of malignant cells through non-conventional mechanisms. In Ewing sarcoma, triggering of CD99 by specific monoclonal antibodies activates hyperstimulation of micropinocytosis and leads to cancer cells killing through a caspase-independent, non-apoptotic pathway resembling methuosis. This process is characterized by extreme accumulation of vacuoles in the cytoplasmic space, which compromises cell viability, requires the activation of RAS-Rac1 downstream signaling and appears to be rather specific for tumor cells. In addition, anti-CD99 monoclonal antibodies exhibit antitumor activities in xenografts in the absence of immune effector cells or complement proteins. Overall, these data establish CD99 as a new opportunity to treat patients with high expression of CD99, particularly those that are resistant to canonical apoptosis-inducing agents. [ABSTRACT FROM AUTHOR]

Polarization is the process by which a macrophage cell commits to a phenotype based on external signal stimulation. To know how this process is affected by random fluctuations and events within a cell is of utmost importance to better understand the underlying dynamics and predict possible phenotype transitions. For this purpose, we develop a stochastic modeling approach for the macrophage polarization process. We classify phenotype states using the Robust Perron Cluster Analysis and quantify transition pathways and probabilities by applying Transition Path Theory. Depending on the model parameters, we identify four bistable and one tristable phenotype configuration. We find that bistable transitions are fast but their states less robust. In contrast, phenotype transitions in the tristable situation have a comparatively long time duration, which reflects the robustness of the states. The results indicate parallels in the overall transition behavior of macrophage cells with other heterogeneous and plastic cell types, such as cancer cells. Our approach allows for a probabilistic interpretation of macrophage phenotype transitions and biological inference on phenotype robustness. In general, the methodology can easily be adapted to other systems where random state switches are known to occur. • We propose a stochastic model for the dynamic change in STAT1 and STAT6 copy numbers. • Parametrizations lead to dynamic switches between two or three different phenotypes. • Transition times and pathways vary largely between the parametrizations. • The transition behavior resembles other heterogeneous cell population dynamics. [ABSTRACT FROM AUTHOR]

The complement system is a critical part of our innate immune response, and the terminal products of this cascade, anaphylatoxins C3a and C5a, exert their physiological and pathophysiological responses primarily via two GPCRs, C3aR and C5aR1. However, the molecular mechanism of ligand recognition, activation, and signaling bias of these receptors remains mostly elusive. Here, we present nine cryo-EM structures of C3aR and C5aR1 activated by their natural and synthetic agonists, which reveal distinct binding pocket topologies of complement anaphylatoxins and provide key insights into receptor activation and transducer coupling. We also uncover the structural basis of a naturally occurring mechanism to dampen the inflammatory response of C5a via proteolytic cleavage of the terminal arginine and the G-protein signaling bias elicited by a peptide agonist of C3aR identified here. In summary, our study elucidates the innerworkings of the complement anaphylatoxin receptors and should facilitate structure-guided drug discovery to target these receptors in a spectrum of disorders. [Display omitted] • Cryo-EM structures of complement receptors C5aR1 and C3aR in complex with G proteins • Molecular mechanism of ligand binding, selectivity, activation, and signaling bias • Structural basis of reduced efficacy of C5ades-Arg through proteolytic cleavage • Discovery and structural mechanism of a subtype-specific biased agonist of C3aR A series of cryo-EM structures offer insights into how anaphylatoxins C3a and C5a engage complement receptors, illustrating agonist binding modes, pathways of receptor activation, and signaling bias that should facilitate the discovery of ligands and therapeutic candidates targeting these receptors. [ABSTRACT FROM AUTHOR]

• The concept for metabolic reprogramming is introduced. • This special issue centers carbohydrate-related metabolism and its reprogramming. • This special issue discusses it as a mechanism for cellular signaling. • Metabolic reprogramming is a promising target for treating human diseases. [ABSTRACT FROM AUTHOR]

Changing the balance between ascorbate, monodehydroascorbate, and dehydroascorbate in plant cells by manipulating the activity of enzymes involved in ascorbate synthesis or recycling of oxidized and reduced forms leads to multiple phenotypes. A systems biology approach including network analysis of the transcriptome, proteome and metabolites of RNAi lines for ascorbate oxidase, monodehydroascorbate reductase and galactonolactone dehydrogenase has been carried out in orange fruit pericarp of tomato (Solanum lycopersicum). The transcriptome of the RNAi ascorbate oxidase lines is inversed compared to the monodehydroascorbate reductase and galactonolactone dehydrogenase lines. Differentially expressed genes are involved in ribosome biogenesis and translation. This transcriptome inversion is also seen in response to different stresses in Arabidopsis. The transcriptome response is not well correlated with the proteome which, with the metabolites, are correlated to the activity of the ascorbate redox enzymes—ascorbate oxidase and monodehydroascorbate reductase. Differentially accumulated proteins include metacaspase, protein disulphide isomerase, chaperone DnaK and carbonic anhydrase and the metabolites chlorogenic acid, dehydroascorbate and alanine. The hub genes identified from the network analysis are involved in signaling, the heat-shock response and ribosome biogenesis. The results from this study therefore reveal one or several putative signals from the ascorbate pool which modify the transcriptional response and elements downstream.

Serotonin (5-hydroxytryptamine, 5-HT) is an important regulator of physiological and behavioral processes in both protostomes (e.g., insects) and deuterostomes (e.g., mammals). In insects, serotonin has been found to modulate the heart rate and to control secretory processes, development, circadian rhythms, aggressive behavior, as well as to contribute to learning and memory. Serotonin exerts its activity by binding to and activating specific membrane receptors. The clear majority of these receptors belong to the superfamily of G-protein-coupled receptors. In Drosophila melanogaster, a total of five genes have been identified coding for 5-HT receptors. From this family of proteins, four have been pharmacologically examined in greater detail, so far. While Dm5-HT1A, Dm5-HT1B, and Dm5-HT7 couple to cAMP signaling cascades, the Dm5-HT2A receptor leads to Ca2+ signaling in an inositol-1,4,5-trisphosphate-dependent manner. Based on sequence similarity to homologous genes in other insects, a fifth D. melanogaster gene was uncovered coding for a Dm5-HT2B receptor. Knowledge about this receptor’s pharmacological properties is very limited. This is quite surprising because Dm5-HT2B has been attributed to distinct physiological functions based on genetic interference with its gene expression. Mutations were described reducing the response of the larval heart to 5-HT, and specific knockdown of Dm5-HT2B mRNA in hemocytes resulted in a higher susceptibility of the flies to bacterial infection. To gain deeper understanding of Dm5-HT2B’s pharmacology, we evaluated the receptor’s response to a series of established 5-HT receptor agonists and antagonists in a functional cell-based assay. Metoclopramide and mianserin were identified as two potent antagonists that may allow pharmacological interference with Dm5-HT2B signaling in vitro and in vivo.

The ketogenic diet (KD) is a broad-spectrum therapy for medically intractable epilepsy and is receiving growing attention as a potential treatment for neurological disorders arising in part from bioenergetic dysregulation. The high-fat/low-carbohydrate “classic KD”, as well as dietary variations such as the medium-chain triglyceride diet, the modified Atkins diet, the low-glycemic index treatment, and caloric restriction, enhance cellular metabolic and mitochondrial function. Hence, the broad neuroprotective properties of such therapies may stem from improved cellular metabolism. Data from clinical and preclinical studies indicate that these diets restrict glycolysis and increase fatty acid oxidation, actions which result in ketosis, replenishment of the TCA cycle (i.e., anaplerosis), restoration of neurotransmitter and ion channel function, and enhanced mitochondrial respiration. Further, there is mounting evidence that the KD and its variants can impact key signaling pathways that evolved to sense the energetic state of the cell, and that help maintain cellular homeostasis. These pathways, which include PPARs, AMP-activated kinase, mammalian target of rapamycin, and the sirtuins, have all been recently implicated in the neuroprotective effects of the KD. Further research in this area may lead to future therapeutic strategies aimed at mimicking the pleiotropic neuroprotective effects of the KD.

Changing the balance between ascorbate, monodehydroascorbate, and dehydroascorbate in plant cells by manipulating the activity of enzymes involved in ascorbate synthesis or recycling of oxidized and reduced forms leads to multiple phenotypes. A systems biology approach including network analysis of the transcriptome, proteome and metabolites of RNAi lines for ascorbate oxidase, monodehydroascorbate reductase and galactonolactone dehydrogenase has been carried out in orange fruit pericarp of tomato (Solanum lycopersicum). The transcriptome of the RNAi ascorbate oxidase lines is inversed compared to the monodehydroascorbate reductase and galactonolactone dehydrogenase lines. Differentially expressed genes are involved in ribosome biogenesis and translation. This transcriptome inversion is also seen in response to different stresses in Arabidopsis. The transcriptome response is not well correlated with the proteome which, with the metabolites, are correlated to the activity of the ascorbate redox enzymes--ascorbate oxidase and monodehydroascorbate reductase. Differentially accumulated proteins include metacaspase, protein disulphide isomerase, chaperone DnaK and carbonic anhydrase and the metabolites chlorogenic acid, dehydroascorbate and alanine. The hub genes identified from the network analysis are involved in signaling, the heat-shock response and ribosome biogenesis. The results from this study therefore reveal one or several putative signals from the ascorbate pool which modify the transcriptional response and elements downstream. [ABSTRACT FROM AUTHOR]

There are numerous extra- and intra-cellular processes involved in the production of reactive oxygen species (ROS). Augmented ROS generation can cause the damage of biomolecules such as proteins, nucleic acid and lipids. ROS act as an intracellular signaling component and is associated with various inflammatory responses, chronic arthropathies, including rheumatoid arthritis (RA). It is well documented that ROS can activate different signaling pathways having a vital importance in the patho-physiology of RA. Hence, understanding of the molecular pathways and their interaction might be advantageous in the development of novel therapeutic approaches for RA. [ABSTRACT FROM AUTHOR]

Malignant gliomas are the most common, infiltrative, and lethal primary brain tumors affecting the adult population. The grim prognosis for this disease is due to a combination of the presence of highly invasive tumor cells that escape surgical resection and the presence of a population of therapy-resistant cancer stem cells found within these tumors. Several studies suggest that glioma cells have cleverly hijacked the normal developmental program of neural progenitor cells, including their transcriptional programs, to enhance gliomagenesis. In this review, we summarize the role of developmentally regulated signaling pathways that have been found to facilitate glioma growth and invasion. Furthermore, we discuss how the microenvironment and treatment-induced perturbations of these highly interconnected signaling networks can trigger a shift in cellular phenotype and tumor subtype. [ABSTRACT FROM AUTHOR]

Loquat (Eriobotrya japonica) leaves have been used as traditional medicine for chemoprevention and treatment of chronic inflammatory diseases although the evidence supporting their functions is still poor. This study aims to clarify the anti-inflammatory effects and molecular mechanisms of loquat tea extract (LTE), in both cell and animal models. LTE, especially C fraction, inhibited the production of pro-inflammatory factors including inducible nitric oxide synthase (iNOS), nitric oxide (NO), IL-6, RANTES and TNF-α. Cellular signaling data revealed that the downregulation of TGF-β-activated kinase (TAK1)-mediated both mitogen-activated protein kinase (MAPK) and NF-κB pathways were involved in the inhibition of pro-inflammatory factors by C fraction. Mouse paws edema model further confirmed the in vivo anti-inflammatory effects of LTE.

G protein-coupled receptors (GPCRs) are major signal recognition and transmission units in the plasma membrane. The interaction of activated and phosphorylated GPCRs with the multifunctional adaptor proteins β-arrestins (βarrs) is crucial for regulation of their signaling and functional outcomes. Over the past few years, a range of structural, biochemical, and cellular studies have revealed novel insights into GPCR–βarr interaction and signaling. Some of these findings have come as a surprise and therefore have the potential to significantly refine the conceptual framework of the GPCR–βarr system. Here we discuss these recent advances with particular emphasis on biphasic GPCR–βarr interaction, the formation of GPCR–G-protein–βarr supercomplexes, and receptor-specific conformational signatures in βarrs. We also underline the emerging research areas that are likely to be at the center stage of investigations in the coming years. [ABSTRACT FROM AUTHOR]

The catecholamines norepinephrine and epinephrine regulate important physiological functions in vertebrates. In insects; these neuroactive substances are functionally replaced by the phenolamines octopamine and tyramine. Phenolamines activate specific guanine nucleotide-binding (G) protein-coupled receptors (GPCRs). Type 1 tyramine receptors are better activated by tyramine than by octopamine. In contrast; type 2 tyramine receptors are almost exclusively activated by tyramine. Functionally; activation of type 1 tyramine receptors leads to a decrease in the intracellular concentration of cAMP ([cAMP]i) whereas type 2 tyramine receptors can mediate Ca2+ signals or both Ca2+ signals and effects on [cAMP]i. Here; we report that the American cockroach (Periplaneta americana) expresses a second type 1 tyramine receptor (PeaTAR1B) in addition to PeaTAR1A (previously called PeaTYR1). When heterologously expressed in flpTM cells; activation of PeaTAR1B by tyramine leads to a concentration-dependent decrease in [cAMP]i. Its activity can be blocked by a series of established antagonists. The functional characterization of two type 1 tyramine receptors from P. americana; PeaTAR1A and PeaTAR1B; which respond to tyramine by changing cAMP levels; is a major step towards understanding the actions of tyramine in cockroach physiology and behavior; particularly in comparison to the effects of octopamine. [ABSTRACT FROM AUTHOR]

Introduction: Gap junctions (GJs) represent the best known intercellular communication (IC) system and are membrane-spanning channels that facilitate intercellular communication by allowing small signaling molecules to pass from cell to cell. In this study, we constructed an amino terminus of human Cx43 (Cx43NT-GFP), verified the overexpression of Cx43-NT in HUVEC cells and explored the impact of gap junctions (GJs) on multiple myeloma (MM).Material and methods: The levels of phosphorylated Cx43(s368) and the change of MAPK pathway associated molecules (ERK1/2, JNK, p38, NFκB) were also investigated in our cell models. Cx43 mRNA and proteins were detected in both MM cell lines and mesenchymal stem cells (MSCs). Dye transfer assays demonstrated that gap junction intercellular communication (GJIC) occurring via Cx43 situated between MM and MSCs or MM and HUVECCx43NT is functional.Results: Our results present evidence for a channel-dependent modulator action of connexin 43 on the migratory activity of MM cells toward MSCs or HUVECCx43-N was higher than those of spontaneous migration (p < 0.05) and protection them from apoptosis in the presence of dexamethasone via cytokines secretion. In the meantime, the migration of MM cells involves an augmented response of p38 and JNK signaling pathway of carboxyl tail of the protein.Conclusions: Our data suggest that GJIC between MM and MSCs is one of the essential factors in tumor cell proliferation and drug sensitivity, and is implicated in MM pathogenesis. [ABSTRACT FROM AUTHOR]