scholarly journals Chemogenetic Tools for Causal Cellular and Neuronal Biology

2018 ◽  
Vol 98 (1) ◽  
pp. 391-418 ◽  
Author(s):  
Deniz Atasoy ◽  
Scott M. Sternson
Keyword(s):  
G Protein ◽  
Ex Vivo ◽  
Cell Types ◽  
Cell Populations ◽  
Specific Cell ◽  
Cellular Processes ◽  
Distinct Cell ◽  
G Protein Coupled ◽  
Pharmacological Control

Chemogenetic technologies enable selective pharmacological control of specific cell populations. An increasing number of approaches have been developed that modulate different signaling pathways. Selective pharmacological control over G protein-coupled receptor signaling, ion channel conductances, protein association, protein stability, and small molecule targeting allows modulation of cellular processes in distinct cell types. Here, we review these chemogenetic technologies and instances of their applications in complex tissues in vivo and ex vivo.

scholarly journals Chemogenetic activation of astrocytes in the hippocampus and cortex changes the transcriptome of microglia and other cell types

2020 ◽  
Author(s):  
Stéphanie Philtjens ◽  
Marion T. Turnbull ◽  
Brian P. Thedy ◽  
Younghye Moon ◽  
Jungsu Kim
Keyword(s):  
Single Cell ◽  
G Protein ◽  
Low Density Lipoprotein ◽  
Ion Homeostasis ◽  
Density Lipoprotein ◽  
Cell Types ◽  
Designer Drugs ◽  
Specific Cell ◽  
G Protein Coupled

AbstractAstrocytes are the most common glial cell type in the brain, yet, it is still not clear how their activation affects the transcriptome of other brain cells such as microglia and neurons. Engineered G protein-coupled receptors called Designer Receptors Exclusively Activated by Designer Drugs (DREADDS) make it possible to selectively activate specific cell types, such as neurons and astrocytes. By combining the selective activation of astrocytes with single cell RNA sequencing, we were able to study transcriptional changes that occur in response to the activation of astrocytes at the single cell level. Interestingly, our data shows that long-term activation of astrocytes in healthy mice results in dramatic alteration in the transcriptome of astrocytes and microglia. Genes that were differentially expressed in these Gq-DREADD-activated astrocytes were involved in neurogenesis and low density lipoprotein particle biology, while those in the microglia were involved in the response to lipoproteins, and the migration and chemotaxis of immune cells. Furthermore, network analysis showed that Gq-DREADD-mediated activation in astrocytes resulted in an upregulation of genes involved in the G protein-coupled receptor signaling pathway and calcium ion homeostasis. This confirmed the activation of astrocytes through the expressed DREADDS. Our findings show the importance of considering the transcriptomic alteration in microglia and neurons after the activation of astrocytes in in vivo models. Therefore, our data will serve as a resource for the broader neuroscience community.

scholarly journals Vascular Abnormalities in Mice Deficient for the G Protein-Coupled Receptor GPR4 That Functions as a pH Sensor

2006 ◽  
Vol 27 (4) ◽  
pp. 1334-1347 ◽  
Author(s):  
Li V. Yang ◽  
Caius G. Radu ◽  
Meenakshi Roy ◽  
Sunyoung Lee ◽  
Jami McLaughlin ◽  
...  
Keyword(s):  
G Protein ◽  
Mesangial Cells ◽  
Ex Vivo ◽  
Extracellular Ph ◽  
Ph Sensing ◽  
G Protein Coupled Receptor ◽  
Vascular Abnormalities ◽  
G Protein Coupled

ABSTRACT GPR4 is a G protein-coupled receptor expressed in the vasculature, lung, kidney, and other tissues. In vitro ectopic overexpression studies implicated GPR4 in sensing extracellular pH changes leading to cyclic AMP (cAMP) production. To investigate its biological roles in vivo, we generated GPR4-deficient mice by homologous recombination. Whereas GPR4-null adult mice appeared phenotypically normal, neonates showed a higher frequency of perinatal mortality. The average litter size from GPR4−/− intercrosses was ∼30% smaller than that from GPR4+/+ intercrosses on N3 and N5 C57BL/6 genetic backgrounds. A fraction of knockout embryos and neonates had spontaneous hemorrhages, dilated and tortuous subcutaneous blood vessels, and defective vascular smooth muscle cell coverage. Mesangial cells in kidney glomeruli were also significantly reduced in GPR4-null neonates. Some neonates exhibited respiratory distress with airway lining cell metaplasia. To examine whether GPR4 is functionally involved in vascular pH sensing, an ex vivo aortic ring assay was used under defined pH conditions. Compared to wild-type aortas, microvessel outgrowth from GPR4-null aortas was less inhibited by acidic extracellular pH. Treatment with an analog of cAMP, a downstream effector of GPR4, abolished microvessel outgrowth bypassing the GPR4-knockout phenotype. These results suggest that GPR4 deficiency leads to partially penetrant vascular abnormalities during development and that this receptor functions in blood vessel pH sensing.

The G Protein-Coupled Receptor cysLT1 Mediates Gi Protein-Dependent Chemotaxis and Adhesion of CD34+ Cells in Vitro Similar to CXCR4, but Not Progenitor Mobilization in Vivo.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1388-1388
Author(s):  
Adriana Drost ◽  
Lena Jaggy ◽  
Lothar Kanz ◽  
Robert Möhle
Keyword(s):  
Bone Marrow ◽  
G Protein ◽  
Actin Polymerization ◽  
Cell Types ◽  
Mediated Effects ◽  
Cd34 Cells ◽  
Gi Protein ◽  
G Protein Coupled

Abstract CysLT1, which is expressed in several cell types during inflammation and allergy, and the homing related chemokine receptor CXCR4 both belong to the family of G protein-coupled receptors (GPCR). Similar to CXCR4, the cysteinyl-leukotriene receptor cysLT1 is strongly expressed in CD34+ cell lines and CD34+ hematopoietic progenitor cells (HPC). We therefore compared the effects mediated by cysLT1 on HPC to those observed after activation of CXCR4. The most potent cysLT1 ligand LTD4 induced chemotaxis and adhesion of CD34+ HPC to endothelial cells, immobilized VCAM-1 and fibronectin, which was comparable to effects induced by the CXCR4 ligand SDF-1. CysLT1- and CXCR4-mediated effects were inhibited by pertussis toxin (PTX), suggesting that both GPCRs employ the same Gi-protein-dependent signaling pathways in CD34+ HPC. This is supported by identical time courses of intracellular calcium fluxes and actin polymerization induced by LTD4 and SDF-1, as measured by time-dependent flow cytometry. Given the striking similarities of cysLT1- and CXCR4-mediated effects in vitro, one might expect also overlapping functions in vivo. We therefore investigated whether blocking of cysLT1 is associated with HPC mobilization. As cysLT1 antagonists are established for therapy and prophylaxis in patients with allergic and exercise-induced asthma, circulating CD34+ progenitors were enumerated after initiation of a treatment with the cysLT1 antagonist montelukast, used as asthma prophylaxis in otherwise healthy subjects. The number of CD34+ cells or white blood counts did not differ significantly from the baseline value 2, 4, 8, 12, and 24 hours after administration of 10 mg montelukast, in contrast to previous studies analyzing stem cell mobilization induced by CXCR4 antagonists. This corresponds with our in vitro findings that LTD4 is produced by bone marrow endothelium and stromal cells only when deprived of hematopoietic cells, in contrast to the constitutive production of SDF-1. We conclude that cysLT1 is not involved in bone marrow retention of HPC during steady-state hematopoiesis, but may modulate HPC homing when its ligands are produced either locally (i.e. bone marrow aplasia) or systemically (i.e. inflammation).

scholarly journals CP-25 inhibits PGE2-induced angiogenesis by down-regulating EP4/AC/cAMP/PKA-mediated GRK2 translocation

2020 ◽  
Vol 134 (3) ◽  
pp. 331-347 ◽  
Author(s):  
Chen-Chen Han ◽  
Qian Liu ◽  
Yu Zhang ◽  
Yi-Fan Li ◽  
Dong-Qian Cui ◽  
...  
Keyword(s):  
G Protein ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Underlying Mechanism ◽  
Tube Formation ◽  
Regulatory Molecule ◽  
Extracellular Signal ◽  
Interfering Rna ◽  
G Protein Coupled

Abstract G protein-coupled receptor kinase 2 (GRK2), a type of cytosolic enzyme, transiently translocates to the plasma membrane upon G protein-coupled receptors (GPCRs) activation, and it also binds to extracellular signal-regulated kinase (ERK) to inhibit the activation of ERK. GRK2 deficiency in endothelial cells (ECs) leads to increased pro-inflammatory signaling and promotes recruitment of leukocytes to activated ECs. However, the role of GRK2 in regulating angiogenesis remains unclear. Here, we show that GRK2 is a novel regulatory molecule on migration and tube formation of ECs, vessel sprouting ex vivo and angiogenesis in vivo. We identify that EP4/AC/cAMP/protein kinase A (PKA)-mediated GRK2 translocation to cells membrane decreases the binding of GRK2 and ERK1/2 to inhibit ERK1/2 activation, which promotes prostaglandin E2 (PGE2)-induced angiogenesis. GRK2 small interfering RNA (siRNA) inhibits the increase in PGE2-induced HUVECs migration and tube formation. In vivo, PGE2 increases ECs sprouting from normal murine aortic segments and angiogenesis in mice, but not from GRK2-deficient ones, on Matrigel. Further research found that Lys220 and Ser685 of GRK2 play an important role in angiogenesis by regulating GRK2 translocation. Paeoniflorin-6′-O-benzene sulfonate (CP-25), as a novel ester derivative of paeoniflorin (pae), has therapeutic potential for the treatment of adjuvant arthritis (AA) and collagen-induced arthritis (CIA), but the underlying mechanism of CP-25 on angiogenesis has not been elucidated. In our study, CP-25 inhibits the migration and tube formation of HUVECs, and angiogenesis in mice by down-regulating GRK2 translocation activation without affecting GRK2 total expression. Taken together, the present results revealed that CP-25 down-regulates EP4/AC/cAMP/PKA-mediated GRK2 translocation, restoring the inhibition of GRK2 for ERK1/2, thereby inhibiting PGE2-stimulated angiogenesis.

scholarly journals Loss of zinc transporters ZIP1 and ZIP3 augments platelet reactivity in response to G protein-coupled receptor agonists and accelerates thrombus formation in vivo

2021 ◽  
Author(s):  
Amro Elgheznawy ◽  
Patricia Oeftering ◽  
Maximilian Englert ◽  
Friederike Kaiser ◽  
Charly Kusch ◽  
...  
Keyword(s):  
G Protein ◽  
Ex Vivo ◽  
Platelet Reactivity ◽  
Thrombus Formation ◽  
Platelet Response ◽  
G Protein Coupled Receptor ◽  
Icp Ms ◽  
And Function ◽  
G Protein Coupled

Zinc (Zn2+) is considered as an important mediator for thrombosis and haemostasis. However, our understanding of the transport mechanisms that regulate Zn2+ homeostasis in platelets is limited. Zn2+ transporters, ZIPs and ZnTs, are widely expressed in eukaryotic cells. Using mice globally lacking ZIP1 and ZIP3 (ZIP1/3 DKO), our aim was to explore the potential role of these well-known Zn2+ transporters in maintaining platelet Zn2+ homeostasis and in the regulation of platelet function. While ICP-MS measurements indicated unaltered overall Zn2+ concentrations in platelets of ZIP1/3 DKO mice, we observed a significantly delayed and less efficient Zn2+ release upon thrombin-stimulated platelet activation. This resulted in a hyperactive platelet response not only in response to thrombin, but also towards other G protein-coupled receptor (GPCR) agonists. Immunoreceptor tyrosine-based activation (ITAM)-coupled receptor agonist signalling, however, was unaffected. Augmented GPCR responses were accompanied by enhanced Ca2+ signalling and PKC activation. Further functional analysis of ZIP1/3 double deficient mice revealed enhanced platelet aggregation, bigger thrombus volume under flow ex vivo and faster in vivo thrombus formation. The current study thereby identifies ZIP1 and ZIP3 as important regulators for the maintenance of platelet Zn2+ homeostasis and function.

Expression of Cardiac Specific Cell Marker in Ex Vivo Differentiated Canine iPSC

2019 ◽  
Author(s):  
Purnima Singh ◽  
Tanmay Mondal ◽  
Kuldeep Kumar ◽  
Kinsuk Das ◽  
N Mahalakshmi ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Ex Vivo ◽  
Cell Types ◽  
Embryoid Bodies ◽  
Specific Gene ◽  
Specific Cell ◽  
Specific Marker ◽  
Cell Based Therapy

Induced Pluripotent stem cells (iPSC) have a high ability to renew and differentiate themselves into various lineages and as vehicles of cell based therapy. Stem cell can differentiate under appropriate in vitro and in vivo conditions into different cell types. This study described the establishment of condition for in vitro expression of alpha MHC gene in cardiac differentiated canine iPSC (ciPSC). In vitro differentiation of canine iPSCs via embryoid bodies (EBs) were produced by ‘Hanging Drop’ method. EB’s were differentiated by using IMDM differentiation media: FBS – 10%, NEAA (100X) – 0.5%, Â-Mercaptoethanol- 100mM, Gentamycin- 5µg/ml supplemented with Azacytidine- 0.5µM. During differentiation, EBs were collected on day 4, 6, 8, 12, 16, 20 and 24 for characterization of cardiomyocytes specific marker expression. Total RNA from EBs were extracted by using Trizol method and subsequently cDNA were synthesized. The differentiated cells expressed cardiac specific gene (Alpha MHC) which started from day 6 of differentiation upto day 24 Immunocytochemistry and relative expression of cardiac specific genes revealed that ciPSC have the potential to differentiate into cardiomyocytes which can be used for cardiac tissue regeneration and as disease models for pharmaceutical testing.

scholarly journals The puzzling uniqueness of the heterotrimeric G15 protein and its potential beyond hematopoiesis

2010 ◽  
Vol 44 (5) ◽  
pp. 259-269 ◽  
Author(s):  
Flavia Giannone ◽  
Giorgio Malpeli ◽  
Veronica Lisi ◽  
Silvia Grasso ◽  
Priyanka Shukla ◽  
...  
Keyword(s):  
G Protein ◽  
G Proteins ◽  
Physiological Role ◽  
Cell Types ◽  
Biochemical Properties ◽  
Membrane Receptors ◽  
General Mechanism ◽  
Specific Cell ◽  
Α Subunit ◽  
G Protein Coupled

Heterotrimeric G proteins transduce the signals of the largest family of membrane receptors (G protein-coupled receptors, GPCRs) hence triggering the activation of a wide variety of physiological responses. G15 is a G protein characterized by a number of functional peculiarities that make its signaling exceptional: 1) it can couple a variety of Gs-, Gi/o-, and Gq-linked receptors to phospholipase C activation; 2) relatively to other G proteins, it is poorly affected by β-arrestin-dependent desensitization, the general mechanism that regulates GPCR function and 3) at the protein level, its expression is only detected in highly specific cell types (hematopoietic and epithelial cells). G15 α-subunit displays unique structural and biochemical properties, and is phylogenetically the most recent and divergent component of the Gαq/11 subfamily. All these aspects shed a mysterious light on G15 biological role, which remains substantially elusive. Thus, far, G15 signaling has been analyzed in the context of hematopoiesis. Here, we highlight observations supporting the view that G15 functions may extend further beyond the immune system. In addition, we describe puzzling aspects of G15 signaling that offer a novel perspective in the understanding of its physiological role.

scholarly journals Type I IFN is siloed in endosomes

2020 ◽  
Vol 117 (30) ◽  
pp. 17510-17512 ◽  
Author(s):  
Jennie B. Altman ◽  
Justin Taft ◽  
Tim Wedeking ◽  
Conor N. Gruber ◽  
Michael Holtmannspötter ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Cell Types ◽  
Specific Cell ◽  
Type I ◽  
Type I Ifn ◽  
Long Term Effects ◽  
Negative Regulators ◽  
Downstream Signaling

Type I IFN (IFN-I) is thought to be rapidly internalized and degraded following binding to its receptor and initiation of signaling. However, many studies report the persistent effects mediated by IFN-I for days or even weeks, both ex vivo and in vivo. These long-lasting effects are attributed to downstream signaling molecules or induced effectors having a long half-life, particularly in specific cell types. Here, we describe a mechanism explaining the long-term effects of IFN-I. Following receptor binding, IFN-I is siloed into endosomal compartments. These intracellular “IFN silos” persist for days and can be visualized by fluorescence and electron microscopy. However, they are largely dormant functionally, due to IFN-I−induced negative regulators. By contrast, in individuals lacking these negative regulators, such as ISG15 or USP18, this siloed IFN-I can continue to signal from within the endosome. This mechanism may underlie the long-term effects of IFN-I therapy and may contribute to the pathophysiology of type I interferonopathies.

G-protein-coupled receptors, channels, and Na+–H+ exchanger in nuclear membranes of heart, hepatic, vascular endothelial, and smooth muscle cellsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 431-441 ◽  
Author(s):  
Ghassan Bkaily ◽  
Moni Nader ◽  
Levon Avedanian ◽  
Sana Choufani ◽  
Danielle Jacques ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
G Protein ◽  
Cell Types ◽  
G Protein Coupled Receptors ◽  
Specific Cell ◽  
Endothelin 1 ◽  
Nuclear Membranes ◽  
Ionic Transporters ◽  
A Cell ◽  
G Protein Coupled

The action of several peptides and drugs is thought to be primarily dependent on their interactions with specific cell surface G-protein-coupled receptors and ionic transporters such as channels and exchangers. Recent development of 3-D confocal microscopy allowed several laboratories, including ours, to identify and study the localization of receptors, channels, and exchangers at the transcellular level of several cell types. Using this technique, we demonstrated in the nuclei of several types of cells the presence of Ca2+ channels as well as Na+–H+ exchanger and receptors such as endothelin-1 and angiotensin II receptors. Stimulation of these nuclear membrane G-protein-coupled receptors induced an increase of nuclear Ca2+. Our results suggest that, similar to the plasma membrane, nuclear membranes possess channels, exchangers and receptors such as those for endothelin-1 and angiotensin II, and that the nucleus seems to be a cell within a cell. This article will emphasize these findings.

Nuclear prostaglandin signaling system: biogenesis and actions via heptahelical receptors

2003 ◽  
Vol 81 (2) ◽  
pp. 196-204 ◽  
Author(s):  
Fernand Gobeil, Jr. ◽  
Alejandro Vazquez-Tello ◽  
Anne Marilise Marrache ◽  
Mosumi Bhattacharya ◽  
Daniella Checchin ◽  
...  
Keyword(s):  
Gene Expression ◽  
G Protein ◽  
Cell Nucleus ◽  
Prostaglandin E ◽  
Specific Cell ◽  
Surface Receptors ◽  
Cellular Processes ◽  
A Cell ◽  
G Protein Coupled ◽  
Specific Cell Surface

Prostaglandins are ubiquitous lipid mediators that play pivotal roles in cardiovascular homeostasis, reproduction, and inflammation, as well as in many important cellular processes including gene expression and cell proliferation. The mechanism of action of these lipid messengers is thought to be primarily dependent on their interaction with specific cell surface receptors that belong to the heptahelical transmembrane spanning G protein-coupled receptor superfamily. Accumulating evidence suggests that these receptors may co-localize at the cell nucleus where they can modulate gene expression through a series of biochemical events. In this context, we have recently demonstrated that prostaglandin E2-EP3 receptors display an atypical nuclear compartmentalization in cerebral microvascular endothelial cells. Stimulation of these nuclear EP3 receptors leads to an increase of eNOS RNA in a cell-free isolated nuclear system. This review will emphasize these findings and describe how nuclear prostaglandin receptors, notably EP3 receptors, may affect gene expression, specifically of eNOS, by identifying putative transducing elements located within this organelle. The potential sources of lipid ligand activators for these intracellular sites will also be addressed. The expressional control of G-protein-coupled receptors located at the perinuclear envelope constitutes a novel and distinctive mode of gene regulation.Key words: PGE2, EP receptors, cell nucleus, signal transduction, gene transcription.

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