Muscarinic receptor M3 contributes to intestinal stem cell maintenance via EphB/ephrin-B signaling.
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ABSTRACT:
SUBMITTER: Takahashi T
PROVIDER: S-EPMC8321669 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The development of central nervous system synapses requires precise coordination between presynaptic and postsynaptic components. The EphB family controls postsynaptic development by interacting with glutamate receptors and regulating dendritic filopodia motility, but how EphBs induce the formation of presynaptic specializations is less well understood. Here, we show that knockdown of presynaptic ephrin-B1, ephrin-B2, or syntenin-1, but not ephrin-B3, prevents EphB-dependent presynaptic development. Ephrin-B1, ephrin-B2, and syntenin-1 are clustered together with presynaptic markers, suggesting that these molecules function jointly in presynaptic development. Knockdown of ephrin-B1 or ephrin-B2 reduces the number of synaptic specializations and the colocalization of syntenin-1 with synaptic markers. Simultaneous knockdown of ephrin-B1 and ephrin-B2 suggests that they function independently in the formation of synaptic contacts, but act together to recruit syntenin-1 to presynaptic terminals. Taken together, these results demonstrate that ephrin-B1 and ephrin-B2 function with EphB to mediate presynaptic development via syntenin-1.
| S-EPMC2787153 | biostudies-literature
Project description:Mesenchymal stromal/stem cells (MSC) express the contact-dependent erythropoietin-producing hepatocellular (Eph) receptor tyrosine kinase family and their cognate ephrin ligands, which are known to regulate thymocyte maturation and selection, T-cell transendothelial migration, activation, co-stimulation, and proliferation. However, the contribution of Eph/ephrin molecules in mediating human MSC suppression of activated T-cells remains to be determined. In the present study, we showed that EphB2 and ephrin-B2 are expressed by ex vivo expanded MSC, while the corresponding ligands, ephrin-B1 and EphB4, respectively, are highly expressed by T-cells. Initial studies demonstrated that EphB2-Fc and ephrin-B2-Fc molecules suppressed T-cell proliferation in allogeneic mixed lymphocyte reaction (MLR) assays compared with human IgG-treated controls. While the addition of a third-party MSC population demonstrated dramatic suppression of T-cell proliferation responses in the MLR, blocking the function of EphB2 or EphB4 receptors using inhibitor binding peptides significantly increased T-cell proliferation. Consistent with these observations, shRNA EphB2 or ephrin-B2 knockdown expression in MSC reduced their ability to inhibit T-cell proliferation. Importantly, the expression of immunosuppressive factors, indoleamine 2, 3-dioxygenase, transforming growth factor-?1, and inducible nitric oxide synthase expressed by MSC, was up-regulated after stimulation with EphB4 and ephrin-B1 in the presence of interferon (IFN)-?, compared with untreated controls. Conversely, key factors involved in T-cell activation and proliferation, such as interleukin (IL)-2, IFN-?, tumor necrosis factor-?, and IL-17, were down-regulated by T-cells treated with EphB2 or ephrin-B2 compared with untreated controls. Studies utilizing signaling inhibitors revealed that inhibition of T-cell proliferation is partly mediated through EphB2-induced ephrin-B1 reverse signaling or ephrin-B2-mediated EphB4 forward signaling by activating Src, PI3Kinase, Abl, and JNK kinase pathways, activated by tyrosine phosphorylation. Taken together, these observations suggest that EphB/ephrin-B interactions play an important role in mediating human MSC inhibition of activated T cells.
| S-EPMC3787464 | biostudies-literature
Project description:BACKGROUND:Liver cancer stem cells (LCSCs) contribute to hepatocellular carcinoma (HCC) development, metastasis, and drug resistance. MSI2 and Notch1 signaling are involved in the maintenance of CSCs. However, it is unknown whether MSI2 and Notch1 are involved in the maintenance of CD44v6+ LCSCs. Therefore, we investigated the clinical significance and function of MSI2 and its relationship with Notch1 signaling in the maintenance of stemness properties in CD44v6+ LCSCs. METHODS:The expression of MSI2 and CD44v6 were detected by fresh specimens and a HCC tissue microarray. The tissue microarray containing 82 HCC samples was used to analyze the correlation between CD44v6 and MSI2. CD44v6+/- cells were isolated using microbeads sorting. We explored the roles of MSI2 and Notch1 signaling in CD44v6+ LCSCs by sphere formation assay, transwell assay, clone formation assay in vitro, and xenograft tumor models in vivo. A Notch RT2 PCR Array, Co-immunoprecipitation, and RNA-immunoprecipitation were used to further investigate the molecular mechanism of MSI2 in activating Notch1 signaling. RESULTS:Here, we found MSI2 expression was positively correlated with high CD44v6 expression in HCC tissues, and further correlated with tumor differentiation. CD44v6+ cells isolated from HCC cell lines exhibited increased self-renewal, proliferation, migration and invasion, resistance to Sorafenib and tumorigenic capacity. Both MSI2 and Notch1 signaling were elevated in sorted CD44v6+ cells than CD44v6- cells and played essential roles in the maintenance of stemness of CD44v6+ LCSCs. Mechanically, MSI2 directly bound to Lunatic fringe (LFNG) mRNA and protein, resulting in Notch1 activation. CONCLUSIONS:Our results demonstrated that MSI2 maintained the stemness of CD44v6+ LCSCs by activating Notch1 signaling through the interaction with LFNG, which could be a potential molecular target for stem cell-targeted therapy for liver cancer.
| S-EPMC6936093 | biostudies-literature
Project description:The M3 muscarinic acetylcholine receptor (CHRM3) is predominantly expressed in the basal epidermal layer where it mediates the effects of the auto/paracrine cytotransmitter acetylcholine. Patients with the autoimmune blistering disease pemphigus develop autoantibodies to CHRM3 and show alterations in keratinocyte adhesion, proliferation and differentiation, suggesting that CHRM3 controls these cellular functions. Chrm3 mice display altered epidermal morphology resembling that seen in patients with pemphigus vulgaris. Here, we characterized the cellular and molecular mechanisms whereby CHRM3 controls epidermal structure and function. We used single cell (sc)RNA-seq to evaluate keratinocyte heterogeneity and identify differentially expressed genes in specific subpopulations of epidermal cells in Chrm3 KO neonatal mice.
2022-05-06 | GSE201885 | GEO
Project description:A diverse repertoire of heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) enables cells to sense their environment. Mammalian olfaction requires the activation of odorant receptors (ORs), the largest family of GPCRs; however, whether ORs functionally interact with other families of GPCRs is unclear. We show that the interaction of ORs with the type 3 muscarinic acetylcholine receptor (M3-R), which is found in olfactory sensory neurons (OSNs), modulated OR responses to cognate odorants. In human embryonic kidney-293T cells, ORs and the M3-R physically interacted, and the M3-R increased the potency and efficacy of odorant-elicited responses of several ORs. Selective M3-R antagonists attenuated odorant-dependent activation of OSNs, and, when the M3-R and ORs were expressed in transfected cells, OR activation was enhanced by muscarinic agonists and inhibited by muscarinic antagonists. Furthermore, M3-R-dependent potentiation of OR signaling synergized with that of receptor transporting protein 1S (RTP1S), an accessory factor required for the efficient membrane targeting of ORs. However, the M3-R did not enhance the abundance of ORs at the cell surface, suggesting that the M3-R acted through a distinct mechanism independent of RTP1S. Finally, the activation of ORs by cognate odorants transactivated the M3-R in the absence of its agonist. The crosstalk between ORs and the M3-R suggests that the functional coupling of ORs and the M3-R is required for robust OR activation.
| S-EPMC3034603 | biostudies-literature
Project description:Fibrocytes are monocyte-derived cells able to differentiate into myofibroblasts-like cells. We have previously shown that they are increased in the bronchi of Chronic Obstructive Pulmonary Disease (COPD) patients and associated to worse lung function. COPD is characterized by irreversible airflow obstruction, partly due to an increased cholinergic environment. Our goal was to investigate muscarinic signalling in COPD fibrocytes. Fibrocytes were isolated from 16 patients with COPD's blood and presence of muscarinic M3 receptor was assessed at the transcriptional and protein levels. Calcium signalling and collagen gels contraction experiments were performed in presence of carbachol (cholinergic agonist) ± tiotropium bromide (antimuscarinic). Expression of M3 receptor was confirmed by Western blot and flow cytometry in differentiated fibrocytes. Immunocytochemistry showed the presence of cytoplasmic and membrane-associated pools of M3. Stimulation with carbachol elicited an intracellular calcium response in 35.7% of fibrocytes. This response was significantly blunted by the presence of tiotropium bromide: 14.6% of responding cells (p < 0.0001). Carbachol induced a significant contraction of fibrocytes embedded in collagen gels (13.6 ± 0.3% versus 2.5 ± 4.1%; p < 0.0001), which was prevented by prior tiotropium bromide addition (4.1 ± 2.7% of gel contraction; p < 0.0001). Finally, M3-expressing fibrocytes were also identified in situ in the peri-bronchial area of COPD patients' lungs, and there was a tendency to an increased density compared to healthy patient's lungs. In conclusion, around 1/3 of COPD patients' fibrocytes express a functional muscarinic M3 receptor. Cholinergic-induced fibrocyte contraction might participate in airway diameter reduction and subsequent increase of airflow resistance in patients with COPD. The inhibition of these processes could participate to the beneficial effects of muscarinic antagonists for COPD treatment.
| S-EPMC9485632 | biostudies-literature
Project description:Thymus organogenesis requires coordinated interactions of multiple cell types, including neural crest (NC) cells, to orchestrate the formation, separation, and subsequent migration of the developing thymus from the third pharyngeal pouch to the thoracic cavity. The molecular mechanisms driving these processes are unclear; however, NC-derived mesenchyme has been shown to play an important role. Here, we show that, in the absence of ephrin-B2 expression on thymic NC-derived mesenchyme, the thymus remains in the cervical area instead of migrating into the thoracic cavity. Analysis of individual NC-derived thymic mesenchymal cells shows that, in the absence of ephrin-B2, their motility is impaired as a result of defective EphB receptor signaling. This implies a NC-derived cell-specific role of EphB-ephrin-B2 interactions in the collective migration of the thymic rudiment during organogenesis.
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Project description:In contrast to most peripheral tissues where multiple subtypes of muscarinic acetylcholine receptor (mAChR) coexist, with each of them playing its part in the orchestra of parasympathetic innervation, the myocardium has been traditionally considered to possess a single mAChR subtype. Although there is much evidence to support the notion that one receptor subtype (M2) orchestrates myocardial muscarinic transduction, there is emerging evidence that M1 and M3 receptors are also expressed and are of potential physiological, pathophysiological and pharmacological relevance. Clarifying this issue has a profound impact on our thinking about the cholinergic control of the heart function and disease and approaches to new drug development for the treatment of heart disease associated with parasympathetic dysfunction. This review article presents evidence for the presence of the M3 receptor subtype in the heart, and analyzes the controversial data from published pharmacological, functional and molecular studies. The potential roles of the M3 receptors, in parasympathetic control of heart function under normal physiological conditions and in heart failure, myocardial ischemia and arrhythmias, are discussed. On the basis of these considerations, we have made some proposals concerning the future of myocardial M3 receptor research.
| S-EPMC1574958 | biostudies-literature
Project description:Graded expression of EphB and ephrin-B along the dorsoventral axis of the retina indicates a role for these bidirectional signalling molecules in dorsoventral-mediolateral retinocollicular mapping. Although previous studies have implicated EphB2 forward signalling in mice, the intracellular component of EphB2 essential for retinocollicular mapping is unknown as are the roles for EphB1, ephrin-B1, and ephrin-B2. Here we show that EphB2 tyrosine kinase catalytic activity and EphB1 intracellular signalling are key mediators of ventral-temporal retinal ganglion cell axon retinocollicular mapping, by likely interacting with ephrin-B1 in the superior colliculus. We further elucidate roles for the ephrin-B2 intracellular domain in retinocollicular mapping and present the unexpected finding that both dorsal and ventral-temporal retinal ganglion cell axons utilize reverse signalling for topographic mapping. These data demonstrate that both forward and reverse signalling initiated by EphB:ephrin-B interactions have a major role in dorsoventral retinal ganglion cell axon termination along the mediolateral axis of the superior colliculus.
| S-EPMC3518405 | biostudies-literature
Project description:The M(3) subtype of muscarinic acetylcholine receptors (M(3)-mAChR) plays a protective role in myocardial ischemia and microRNAs (miRNAs) participate in many cardiac pathophysiological processes, including ischemia-induced cardiac injury. However, the role of miRNAs in M(3)-mAChR mediated cardioprotection remains unexplored. The present study was designed to identify miRNAs that are involved in cardioprotective effects of M(3)-mAChR against myocardial ischemia and elucidate the underlying mechanisms. We established rat model of myocardial ischemia and performed miRNA microarray analysis to identify miRNAs involved in the cardioprotection of M(3)-mAChR. In H9c2 cells, the viability, intracellular free Ca(2+) concentration ([Ca(2+)]i), intracellular reactive oxygen species (ROS), miR-376b-5p expression level, brain derived neurophic factor (BDNF) and nuclear factor kappa-B (NF-?B) levels were measured. Our results demonstrated that M(3)-mAChR protected myocardial ischemia injury. Microarray analysis and qRT-PCR revealed that miR-376b-5p was significantly up-regulated in ischemic heart tissue and the M(3)-mAChRs agonist choline reversed its up-regulation. In vitro, miR-376b-5p promoted H(2)O(2)-induced H9c2 cell injuries measured by cells viability, [Ca(2+)]i and ROS. Western blot and luciferase assay identified BDNF as a direct target of miR-376b-5p. M(3)-mAChR activated NF-?B and thereby inhibited miR-376b-5p expression. Our data show that a novel M(3)-mAChR/NF-?B/miR-376b-5p/BDNF axis plays an important role in modulating cardioprotection. MiR-376b-5p promotes myocardial ischemia injury possibly by inhibiting BDNF expression and M(3)-mAChR provides cardioprotection at least partially mediated by the downregulation of miR-376b-5p through NF-?B. These findings provide new insight into the potential mechanism by which M(3)-mAChR provides cardioprotection against myocardial ischemia injury.
| S-EPMC3292572 | biostudies-literature