Intercellular Signal Transduction Research Articles

Emerging role of mTOR in tumor immune contexture: Impact on chemokine-related immune cells migration.

During the last few decades, cell-based anti-tumor immunotherapy emerged and it has provided us with a large amount of knowledge. Upon chemokines recognition, immune cells undergo rapid trafficking and activation in disease milieu, with immune cells chemotaxis being accompanied by activation of diverse intercellular signal transduction pathways. The outcome of chemokines-mediated immune cells chemotaxis interacts with the cue of mammalian target of rapamycin (mTOR) in the tumor microenvironment (TME). Indeed, the mTOR cascade in immune cells involves migration and infiltration. In this review, we summarize the available mTOR-related chemokines, as well as the characterized upstream regulators and downstream targets in immune cells chemotaxis and assign potential underlying mechanisms in each evaluated chemokine. Specifically, we focus on the involvement of mTOR in chemokine-mediated immune related cells in the balance between tumor immunity and malignancy.

Integrin Beta 5 Is a Prognostic Biomarker and Potential Therapeutic Target in Glioblastoma.

Background: Glioblastoma (GBM) is the most lethal cancer of the central nervous system. Integrin beta 5 (ITGB5) is thought to be involved in intercellular signal transduction and regulation of tumor initiation and progression. However, the function of ITGB5 in GBM is not known.Methods: To address this question, we evaluated the expression level of ITGB5 in clinical specimens by immunohistochemistry and western blotting, as well as the association between ITGB5 expression and GBM patient survival using data from Chinese Glioma Genome Atlas and The Cancer Genome Atlas. The biological function of ITGB5 in GBM was investigated by Gene Ontology, gene set enrichment, and in vitro loss-of-function experiments using glioma cells.Results: Among integrin family members, ITGB5 showed the greatest difference in expression between low-grade glioma and GBM. Elevated ITGB5 expression was highly correlated with glioma progression and a mesenchymal subtype and poor survival in GBM patients. ITGB5 was found to be associated with regulation of the immune response and angiogenesis in GBM, and was required for migration and invasion of glioma cells and tube formation by endothelial cells.Conclusions: These data indicate that ITGB5 can serve as a predictive biomarker for GBM patient survival and is a potential therapeutic target in GBM treatment.

Protective role of exogenous recombinant peroxiredoxin 6 under ischemia-reperfusion injury of kidney.

Peroxiredoxin 6 (Prx6) is an important antioxidant enzyme with various functions in the cell. Prx6 reduces a wide range of peroxide substrates, playing a leading role in maintaining the redox homeostasis of mammalian cells. In addition to the peroxidase activity, a phospholipase A2-like activity was demonstrated for Prx6, which plays an important role in the metabolism of membrane phospholipids. Besides that, due to its peroxidase and phospholipase activities, Prx6 participates in intracellular and intercellular signal transduction, thus triggering regenerative processes in the cell, suppressing apoptosis caused by various factors, including ischemia-reperfusion injuries. A nephroprotective effect of exogenous recombinant Prx6 administered before ischemia-reperfusion injury was demonstrated on an animal model. Exogenous Prx6 effectively alleviates the severeness of renal ischemia-reperfusion injuries and facilitates normalization of their structural and functional conditions. Infusion of exogenous Prx6 increases the survival rate of experimental animals by almost 3 times. Application of exogenous Prx6 can be an effective approach in the prevention and treatment of renal ischemia-reperfusion kidney lesions and in preserving isolated kidneys during transplantation.

Hydrogel Skin-Covered Neurons Self-Assembled with Gustatory Cells for Selective Taste Stimulation

Many technical challenges exist in the co-culture of multiple types of cells, including medium optimization, cell-to-cell connection, and selective data acquisition of cellular responses. Particularly, mixed cellular responses limit the precise interpretation of intercellular signal transduction. Here, we report the formation of an agarose gel skin on neurons closely assembled with gustatory cells to selectively stimulate gustatory cells by retarding the diffusion of tastants to neurons. The signal transmission, triggered by denatonium benzoate, from gustatory cells to neurons was monitored using intracellular calcium ion concentrations. The agarose gel skin efficiently suppressed the direct transfer of tastants to neurons, decreasing the number of responsive neurons from 56 to 13% and the number of calcium ion signals per neuron from multiple to single. The assembly of neurons with gustatory cells induced the high level of neuronal responses through taste signal transduction from gustatory cells to neurons. However, the calcium ion signal peaks of free neurons coated with agarose gel were much shorter and weaker than those of neurons closely assembled with gustatory cells. This work demonstrated that agarose gel skin is a simple, fast, and effective means to increase the signal selectivity of cellular responses in the co-culture of multiple types of cells.

MTOR and Aging: An Old Fashioned Dress.

Aging is a physiologic/pathologic process characterized by a progressive impairment of cellular functions, supported by the alterations of several molecular pathways, leading to an increased cell susceptibility to injury. This deterioration is the primary risk factor for several major human pathologies. Numerous cellular processes, including genomic instability, telomere erosion, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, stem cell exhaustion, and altered intercellular signal transduction represent common denominators of aging in different organisms. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved nutrient sensing protein kinase that regulates growth and metabolism in all eukaryotic cells. Studies in flies, worms, yeast, and mice support the hypothesis that the mTOR signalling network plays a pivotal role in modulating aging. mTOR is emerging as the most robust mediator of the protective effects of various forms of dietary restriction, which has been shown to extend lifespan and slow the onset of age-related diseases across species. Herein we discuss the role of mTor signalling network in the development of classic age-related diseases, focused on cardiovascular system, immune response, and cancer.

Radioprotective Role of Peroxiredoxin 6.

Peroxiredoxin 6 (Prdx6) is a member of an evolutionary ancient family of peroxidase enzymes with diverse functions in the cell. Prdx6 is an important enzymatic antioxidant. It reduces a wide range of peroxide substrates in the cell, thus playing a leading role in the maintenance of the redox homeostasis in mammalian cells. Beside peroxidase activity, Prdx6 has been shown to possess an activity of phospholipase A2, an enzyme playing an important role in membrane phospholipid metabolism. Moreover, Prdx6 takes part in intercellular and intracellular signal transduction due to its peroxidase and phospholipase activity, thus facilitating the initiation of regenerative processes in the cell, suppression of apoptosis, and activation of cell proliferation. Being an effective and important antioxidant enzyme, Prdx6 plays an essential role in neutralizing oxidative stress caused by various factors, including action of ionizing radiation. Endogenous Prdx6 has been shown to possess a significant radioprotective potential in cellular and animal models. Moreover, intravenous infusion of recombinant Prdx6 to animals before irradiation at lethal or sublethal doses has shown its high radioprotective effect. Exogenous Prdx6 effectively alleviates the severeness of radiation lesions, providing normalization of the functional state of radiosensitive organs and tissues, and leads to a significant elevation of the survival rate of animals. Prdx6 can be considered as a potent and promising radioprotective agent for reducing the pathological effect of ionizing radiation on mammalian organisms. The radioprotective properties and mechanisms of radioprotective action of Prdx6 are discussed in the current review.

CCN3 and DLL1 co-regulate osteogenic differentiation of mouse embryonic fibroblasts in a Hey1-dependent manner

Notch signaling pathway is one of the most important pathways to regulate intercellular signal transduction and is crucial in the regulation of bone regeneration. Nephroblastoma overexpressed (NOV or CCN3) serves as a non-canonical secreted ligand of Notch signaling pathway and its role in the process of osteogenic differentiation of mesenchymal stem cells (MSCs) was undefined. Here we conducted a comprehensive study on this issue. In vivo and in vitro studies have shown that CCN3 significantly inhibited the early and late osteogenic differentiation of mouse embryonic fibroblasts (MEFs), the expression of osteogenesis-related factors, and the subcutaneous ectopic osteogenesis of MEFs in nude mice. In mechanism studies, we found that CCN3 significantly inhibited the expression of BMP9 and the activation of BMP/Smad and BMP/MAPK signaling pathways. There was also a mutual inhibition between CCN3 and DLL1, one of the classic membrane protein ligands of Notch signaling pathway. Additionally, we further found that Hey1, the target gene shared by BMP and Notch signaling pathways, partially reversed the inhibitory effect of CCN3 on osteoblastic differentiation of MEFs. In summary, our findings suggested that CCN3 significantly inhibited the osteogenic differentiation of MEFs. The inhibitory effect of CCN3 was mainly through the inhibition of BMP signaling and the mutual inhibition with DLL1, so as to inhibit the expression of Hey1, the target gene shared by BMP and Notch signaling pathways.

Molecular targeted therapy of osteosarcoma and related clinical

Osteosarcomais a highly heterogeneous bone cancer, which predominantly affects children andadolescents population. The outcome of patients with osteosarcoma has not changed in several decades. This plateau in survival rates highlights the need for a novel approach towards research. Novel precise osteosarcoma-targeting therapyis also developingand attempwith the hope ofaddressing this issue. This reviewsummarizes the current development of molecular mechanism underlying osteosarcoma, current molecular therapeutic targets against immune system, extracellular and intercellular signalingtransduction pathway of the bone metabolism, microRNA, as well as therapies that target these mechanisms with updated informationon fundamental research, preclinical study, and clinical trials. To date, even though few targeted drugs that specifically targeting osteosarcoma have been approved for clinical use, these new approaches that mentioned above and new strategies and methords for clinical trialcouldhelp us explore the full potential of targeted therapies in osteosarcoma.

Progress of tumor-derived exosomal microRNA in tumors

Exosomes are vesicular globules with physiological functions, such as intercellular material transportation and signal transduction. They can be secreted by many kinds of cells, with 40 to 100 nm diameters. Exosomes have biological properties of derived cells based on the nucleic acids, proteins and lipids in them. Tumor cells can also secrete large number of exosomes with many microRNAs (miRNAs), and miRNAs from different maternal tumor cells are different. This paper mainly reviews the early diagnosis of tumors by tumor-derived exosomal miRNAs and the relationship between miRNAs and tumorigenesis and tumor progression. Key words: Neoplasms; Exosomes; MicroRNAs

Intracellular Calcium Mobilization Is Required for Sonic Hedgehog Signaling

Graded Shh signaling across fields of precursor cells coordinates patterns of gene expression, differentiation, and morphogenetic behavior as precursors form complex structures, such as the nervous system, the limbs, and craniofacial skeleton. Here we discover that intracellular calcium mobilization, a process tightly controlled and readily modulated, regulates the level of Shh-dependent gene expression in responding cells and affects the development of all Shh-dependent cell types in the zebrafish embryo. Reduced expression or modified activity of ryanodine receptor (RyR) intracellular calcium release channels shifted the allocation of Shh-dependent cell fates in the somitic muscle and neural tube. Mosaic analysis revealed that RyR-mediated calcium mobilization is required specifically in Shh ligand-receiving cells. This work reveals that RyR channels participate in intercellular signal transduction events. As modulation of RyR activity modifies tissue patterning, we hypothesize that alterations in intracellular calcium mobilization contribute to both birth defects and evolutionary modifications of morphology.

Next-generation sequencing-based miRNA expression analysis in Parp1-deficient embryonic stem cell-derived exosomes

Poly (ADP-ribose) polymerase family, member 1 (Parp1) has pleiotropic and disparate functions in multiple cellular signaling pathways through post-translational protein modification. It contributes to the regulation of various cellular processes, including DNA damage repair, cell death, and cell differentiation, genetically or epigenetically. Meanwhile, the functions of Parp1 in intercellular signaling remain to be established. To examine the functions of Parp1 in intercellular signaling, we examined microRNA (miRNA) regulation in exosomes derived from Parp1-deficient (Parp1−/−) embryonic stem (ES) cells. The percentages of miRNAs among total RNAs, including small RNAs such as miRNAs, snRNAs, snoRNAs, tRNAs, exonic RNAs, and intronic RNAs, in Parp1+/+ and Parp1−/− ES cell-derived exosomes were 8.2% and 3.5%, respectively. Overall, 329 distinct miRNAs exhibited ≥2-fold changes (118 upregulated; 211 downregulated). The upregulated miRNAs targeted 810 candidate genes, and the downregulated miRNAs targeted 716 candidate genes. Pathway analyses revealed that the upregulated miRNAs were significantly associated with five pathways including MAPK signaling cascades (p < 0.05), indicating that the target genes in these pathways were suppressed in Parp1−/− ES cells. In quantitative analyses of miRNA expression, miR365-3p, let-7a-5p, miR196b-5p, miR203-3p, miR98-5p, and miR146a-5p were increased by ≥ 2-fold in Parp1−/− ES cell-derived exosomes. Gene ontology enrichment analyses revealed that the upregulated miRNAs were significantly annotated for growth and stress-related cell signaling and cell communication (p < 0.05). Parp1 deficiency in ES cells led to inhibition of cell–cell communication, possibly by intercellular signal transduction, suggesting that Parp1 functions extracellularly by regulating exosomal miRNAs.

A cell surface specific two-photon fluorescent probe for monitoring intercellular transmission of hydrogen sulfide

Hydrogen sulfide (H2S) is a new endogenously generated gasotransmitter and has implicated in many physiologies and pathologies closely related to its intracellular and intercellular signaling transduction. Although many fluorescent probes have been exploited to track and quantify H2S in living systems, none of them could be used for monitoring intercellular transmission of H2S. Herein, we developed a cell surface specific H2S probe, 4-azido-6-sulfo-N-hexadecyl-1,8-naphthalimide, sodium salt (ASNHN-N3), trying to investigate the behaviors of extracellular release of H2S. ASNHN-N3 is week fluorescent and could react with H2S at 37 °C in pH 7.4 buffer solutions to form product ASNHN-NH2 with strong fluorescence (Φ = 0.22). Using ASNHN-N3 as H2S probe, excellent linear correlation versus the concentration of NaHS was obtained ranging from 0 to 10 μM and the detection limit was 0.75 μM. With the lipid anchor and the hydrophilic sulfonic group introduced into the 1,8-naphthalimide (a skeleton of two-photon fluorescent probe), the amphiphilic probe is located at the surface of living cells which can record H2S efflux from the cell diffusing across the plasma membrane in living cells and deep-tissue by using two-photon microscopy. Thus we present a new strategy for further studying the mechanism of signaling molecules in cell communication and signal pathways.

Alternative dimerization of receptor tyrosine kinases with signal transduction through a cellular membrane

Receptor tyrosine kinases (RTKs) occupy a separate functional niche among membrane receptors, which is determined by the special features of mechanisms of the signal transduction through a cellular membrane. RTKs are involved in the regulation of development and homeostasis of all the tissues of a human organism, playing a central role in cell proliferation, differentiation, and adhesion. A necessary condition of the biochemical signal transduction through a plasmatic membrane is a ligand-dependent or a ligand-independent dimerization (and/or an oligomerization) of RTKs which is accompanied by conformational rearrangements of all the RTK domains, including the α-helical transmembrane segments. In this review, the main aspects of structure-function relationship for RTKs from various receptor subfamilies are briefly discussed. It is shown in the light of the recently obtained biophysical and biochemical data that functioning of RTK receptors is mediated not only by protein–protein interactions, but by the state of the lipid environment as one of the main components of a self-consistent signal transduction system as well. The new principles of intercellular signal transduction through a membrane replenish the molecular mechanisms of the RTK functioning that have been earlier proposed and explain a number of paradoxes which are observed upon activation of wild-type receptors and the receptors with pathogenic transmembrane mutations. Understanding of the complex mechanisms of the signaling processes can facilitate the successful search for new opportunities of influence on the RTK biological functions with potential therapeutic consequences.

Genome-wide analysis of the GST gene family in Gossypium hirsutum L.

Glutathione-S-transferase (GST) is a ubiquitous multi-functional protein superfamily that plays important roles in plant primary and secondary metabolism, stress and intercellular signal transduction. Concomitantly, it also functions as a ligand in the metabolism of plant hormones and substance transport. In order to understand the GST gene family in upland cotton (Gossypium hirsutum L.), herein we analyzed the species, evolutionary relationship, physical location, gene structure, conserved motifs and expression patterns. We identified 70 GST genes in the whole genome of upland cotton, and divided them into U, F, T, Z, EF1Bγ and TCHQD groups by phylogenetic tree and gene structure analyses. The gene mapping analysis indicated that the GST genes were on every chromosome except chromosome AD/At2, AD/At4, AD/At5, AD/Dt5 and AD/Dt10. Moreover, the GST gene cluster appeared on four chromosomes (AD/At9, AD/Dt7, AD/Dt12 and AD/Dt13). qRT-PCR assays showed that eight genes (GhGSTF2-9) were expressed in the root, stem, leave and fiber of different developmental stages while GhGSTF1 might be a pseudogene. Combining qRT-PCR and bioinformatic analysis, we speculated that GhGSTF8 might be involved in the transport and accumulation of proanthocyanidins/anthocyanins; GhGSTF4, 6 and 9 might play roles in regulating the growth and stress response of upland cotton; the function of GhGSTF2, 3, 5 and 7 remains to be further investigated. Our work provides a theoretical basis for further studies on the molecular evolution and function of the GST gene family in upland cotton.

VEGF isoforms have differential effects on permeability of human pulmonary microvascular endothelial cells

BackgroundAlternative splicing of Vascular endothelial growth factor-A mRNA transcripts (commonly referred as VEGF) leads to the generation of functionally differing isoforms, the relative amounts of which have potentially significant physiological outcomes in conditions such as acute respiratory distress syndrome (ARDS). The effect of such isoforms on pulmonary vascular permeability is unknown. We hypothesised that VEGF165a and VEGF165b isoforms would have differing effects on pulmonary vascular permeability caused by differential activation of intercellular signal transduction pathways.MethodTo test this hypothesis we investigated the physiological effect of VEGF165a and VEGF165b on Human Pulmonary Microvascular Endothelial Cell (HPMEC) permeability using three different methods: trans-endothelial electrical resistance (TEER), Electric cell-substrate impedance sensing (ECIS) and FITC-BSA passage. In addition, potential downstream signalling pathways of the VEGF isoforms were investigated by Western blotting and the use of specific signalling inhibitors.ResultsVEGF165a increased HPMEC permeability using all three methods (paracellular and transcellular) and led to associated VE-cadherin and actin stress fibre changes. In contrast, VEGF165b decreased paracellular permeability and did not induce changes in VE-cadherin cell distribution. Furthermore, VEGF165a and VEGF165b had differing effects on both the phosphorylation of VEGF receptors and downstream signalling proteins pMEK, p42/44MAPK, p38 MAPK, pAKT and peNOS. Interestingly specific inhibition of the pMEK, p38 MAPK, PI3 kinase and eNOS pathways blocked the effects of both VEGF165a and VEGF165b on paracellular permeability and the effect of VEGF165a on proliferation/migration, suggesting that this difference in cellular response is mediated by an as yet unidentified signalling pathway(s).ConclusionThis study demonstrates that the novel isoform VEGF165a and VEGF165b induce differing effects on permeability in pulmonary microvascular endothelial cells.

Dissecting Pistil Responses to Incompatible and Compatible Pollen in Self-Incompatibility Brassica oleracea Using Comparative Proteomics.

Angiosperms have developed self-incompatibility (SI) systems to reject self-pollen, thereby promoting outcrossing. The Brassicaceae belongs to typical sporophytic system, having a single S-locus controlled SI response, and was chosen as a model system to study SI-related intercellular signal transduction. In this regard, the downstream factor of EXO70A1 was unknown. Here, protein two-dimensional electrophoresis (2-DE) method and coupled with matrix-assisted laser desorption ionization/time of flight of flight mass spectrometry (MALDI-TOF -MS) and peptide mass fingerprinting (PMF) was used to further explore the mechanism of SI responses in Brassica oleracea L. var. capitata L. at protein level. To further confirm the time point of protein profile change, total proteins were collected from B. oleracea pistils at 0min, 1h, and 2h after self-pollination. In total 902, 1088 and 1023 protein spots were separated in 0min, 1h and 2h 2-DE maps, respectively. Our analyses of self-pollination profiles indicated that proteins mainly changed at 1h post-pollination in B. oleracea. Moreover, 1077 protein spots were separated in cross-pollinated 1h (CP) pistil 2-DE map. MALDI-TOF-MS and PMF successfully identified 34 differentially-expressed proteins (DEPs) in SP and CP 1h 2-DE maps. Gene ontology and KEGG analysis revealed an array of proteins grouped in the following categories: stress and defense response (35%), protein metabolism (18%), carbohydrate and energy metabolism (12%), regulation of translation (9%), pollen tube development (12%), transport (9%) and cytoskeletal (6%). Sets of DEPs identified specifically in SP or only up-regulated expressed in CP pistils were chosen for funther investigating in floral organs and during the process of self- and cross-pollination. The function of these DEPs in terms of their potential involvement in SI in B. oleracea is discussed.

Capacity of a Simple Intercellular Signal Transduction Channel

We model the ligand-receptor molecular communication channel with a discrete-time Markov model, and show how to obtain the capacity of this channel. We show that the capacity-achieving input distribution is iid; further, unusually for a channel with memory, we show that feedback does not increase the capacity of this channel.

The application of insulin-like growth factors system in the diagnosis and treatment of tumor

Malignancies threaten human health seriously. Recently studies show that intercellular signal transduction influences the biological characteristics of tumor cells. It has closely relationship with tumor growth and metastasis. Insulin-like growth factor (IGFs) signal transduction system is a potential mitogen that distributed in the body's tissues, organs and blood. Researches show that the abnormal expression of IGFs exists in many tissues, such as breast cancer, colorectal cancer, gastric carcinoma, lung carcinoma, pancreatic cancer and so on, which may play an important role in occurrence and metastasis as a novel tumor marker.(Chin J Lab Med, 2016, 39: 575-577) Key words: Neoplasms; Somatomedins; Signal transduction; Tumor markers, biological

Association between microRNAs and psoriasis-related signaling pathways

The control of cell growth, differentiation and apoptosis is realized through intercellular signal transduction dependent on activation of signaling molecules. Abnormity in intercellular signal transduction usually contributes to the occurrence of diseases. Studies have demonstrated that the occurrence of psoriasis is related to multiple abnormal signaling pathways, mainly including the mitogenactivated protein kinase (MAPK)signaling pathway, nonreceptor tyrosine kinases Janus kinase/signal transducer and activator of transcription (JAK/STAT)pathway, tumor necrosis factor α (TNF-α)signaling pathway and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)signaling pathway. Furthermore, abnormality in these pathways is also associated with microRNA-mediated post-transcriptional regulation. Key words: Psoriasis; MicroRNAs; Signal transduction; Tumor necrosis factor-alpha; Janus kinases

Establishment and identification of the near-infrared fluorescence labeled exosomes in breast cancer cell lines

Exosomes, a population of extracellular membrane vesicles of 30-100 nm in diameter, play important roles in cell biological functions, intercellular signal transduction and especially in cancer diagnosis and therapy. To better apply exosomes in mechanistic study of breast cancer signal transduction, we constructed recombinant eukaryotic expression vector expressing the near-infrared fluorescence protein and CD63 fusion protein through cloning iRFP682 gene and exosomal marker protein CD63 gene into plasmid containing the ITR of AAV. The constructed plasmids were co-transfected with helper plasmid in AAV-293 cell lines and were packaged into rAAV. After titer measurement, the recombinant plasmids were transfected into breast cancer cell lines. The cell lines that stably expressing near-infrared fluorescence protein were selected by fluorescence. Through isolation, purification and identification, we finally obtained a new biomarker: iRFP682 labeled exosomes secreted by breast cancer cell lines, which could be used in further studies of the distribution and signal transduction of exosomes in breast cancer microenvironment.