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Bai, Xilian, George J. Bugg, Susan L. Greenwood, Jocelyn D. Glazier, Colin P. Sibley, Philip N. Baker, Michael J. Taggart, and Gregor K. Fyfe. "Expression of TASK and TREK, two-pore domain K+ channels, in human myometrium." Reproduction 129, no. 4 (April 2005): 525–30. http://dx.doi.org/10.1530/rep.1.00442.
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Two-pore domain K+channels are an emerging family of K+channels that may contribute to setting membrane potential in both electrically excitable and non-excitable cells and, as such, influence cellular function. The human uteroplacental unit contains both excitable (e.g. myometrial) and non-excitable cells, whose function depends upon the activity of K+channels. We have therefore investigated the expression of two members of this family, TWIK (two-pore domain weak inward rectifying K+channel)-related acid-sensitive K+channel (TASK) and TWIK-related K+channel (TREK) in human myometrium. Using RT-PCR the mRNA expression of TASK and TREK isoforms was examined in myometrial tissue from pregnant women. mRNAs encoding TASK1, 4 and 5 and TREK1 were detected whereas weak or no signals were observed for TASK2, TASK3 and TREK2. Western blotting for TASK1 gave two bands of approximately 44 and 65 kDa, whereas TREK1 gave bands of approximately 59 and 90 kDa in myometrium from pregnant women. TASK1 and TREK1 immunofluorescence was prominent in intracellular and plasmalemmal locations within myometrial cells. Therefore, we conclude that the human myometrium is a site of expression for the two-pore domain K+channel proteins TASK1 and TREK1.
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Afzali, Ali M., Tobias Ruck, Alexander M. Herrmann, Janette Iking, Claudia Sommer, Christoph Kleinschnitz, Corinna Preuβe, et al. "The potassium channels TASK2 and TREK1 regulate functional differentiation of murine skeletal muscle cells." American Journal of Physiology-Cell Physiology 311, no. 4 (October 1, 2016): C583—C595. http://dx.doi.org/10.1152/ajpcell.00363.2015.
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Two-pore domain potassium (K2P) channels influence basic cellular parameters such as resting membrane potential, cellular excitability, or intracellular Ca2+-concentration [Ca2+]i. While the physiological importance of K2P channels in different organ systems (e.g., heart, central nervous system, or immune system) has become increasingly clear over the last decade, their expression profile and functional role in skeletal muscle cells (SkMC) remain largely unknown. The mouse SkMC cell line C2C12, wild-type mouse muscle tissue, and primary mouse muscle cells (PMMs) were analyzed using quantitative PCR, Western blotting, and immunohistochemical stainings as well as functional analysis including patch-clamp measurements and Ca2+ imaging. Mouse SkMC express TWIK-related acid-sensitive K+ channel (TASK) 2, TWIK-related K+ channel (TREK) 1, TREK2, and TWIK-related arachidonic acid stimulated K+ channel (TRAAK). Except TASK2 all mentioned channels were upregulated in vitro during differentiation from myoblasts to myotubes. TASK2 and TREK1 were also functionally expressed and upregulated in PMMs isolated from mouse muscle tissue. Inhibition of TASK2 and TREK1 during differentiation revealed a morphological impairment of myoblast fusion accompanied by a downregulation of maturation markers. TASK2 and TREK1 blockade led to a decreased K+ outward current and a decrease of ACh-dependent Ca2+ influx in C2C12 cells as potential underlying mechanisms. K2P-channel expression was also detected in human muscle tissue by immunohistochemistry pointing towards possible relevance for human muscle cell maturation and function. In conclusion, our findings for the first time demonstrate the functional expression of TASK2 and TREK1 in muscle cells with implications for differentiation processes warranting further investigations in physiologic and pathophysiologic scenarios.
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Park, Kyoung Sun, and Yangmi Kim. "Functional expression of TREK1 channel in human bone marrow and human umbilical cord vein-derived mesenchymal stem cells." Journal of the Korea Academia-Industrial cooperation Society 16, no. 3 (March 31, 2015): 1964–71. http://dx.doi.org/10.5762/kais.2015.16.3.1964.
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Ghatak, Swagata, and Sujit Kumar Sikdar. "Lactate modulates the intracellular pH sensitivity of human TREK1 channels." Pflügers Archiv - European Journal of Physiology 468, no. 5 (February 3, 2016): 825–36. http://dx.doi.org/10.1007/s00424-016-1795-8.
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Srisomboon, Yotesawee, Nathan A. Zaidman, Peter J. Maniak, Chatsri Deachapunya, and Scott M. O’Grady. "P2Y receptor regulation of K2P channels that facilitate K+ secretion by human mammary epithelial cells." American Journal of Physiology-Cell Physiology 314, no. 5 (May 1, 2018): C627—C639. http://dx.doi.org/10.1152/ajpcell.00342.2016.
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The objective of this study was to determine the molecular identity of ion channels involved in K+ secretion by the mammary epithelium and to examine their regulation by purinoceptor agonists. Apical membrane voltage-clamp experiments were performed on human mammary epithelial cells where the basolateral membrane was exposed to the pore-forming antibiotic amphotericin B dissolved in a solution with intracellular-like ionic composition. Addition of the Na+ channel inhibitor benzamil reduced the basal current, consistent with inhibition of Na+ uptake across the apical membrane, whereas the KCa3.1 channel blocker TRAM-34 produced an increase in current resulting from inhibition of basal K+ efflux. Treatment with two-pore potassium (K2P) channel blockers quinidine, bupivacaine and a selective TASK1/TASK3 inhibitor (PK-THPP) all produced concentration-dependent inhibition of apical K+ efflux. qRT-PCR experiments detected mRNA expression for nine K2P channel subtypes. Western blot analysis of biotinylated apical membranes and confocal immunocytochemistry revealed that at least five K2P subtypes (TWIK1, TREK1, TREK2, TASK1, and TASK3) are expressed in the apical membrane. Apical UTP also increased the current, but pretreatment with the PKC inhibitor GF109203X blocked the response. Similarly, direct activation of PKC with phorbol 12-myristate 13-acetate produced a similar increase in current as observed with UTP. These results support the conclusion that the basal level of K+ secretion involves constitutive activity of apical KCa3.1 channels and multiple K2P channel subtypes. Apical UTP evoked a transient increase in KCa3.1 channel activity, but over time caused persistent inhibition of K2P channel function leading to an overall decrease in K+ secretion.
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Kondo, Rubii, Akari Deguchi, Naoki Kawata, Yoshiaki Suzuki, and Hisao Yamamura. "Involvement of TREK1 channels in the proliferation of human hepatic stellate LX-2 cells." Journal of Pharmacological Sciences 148, no. 3 (March 2022): 286–94. http://dx.doi.org/10.1016/j.jphs.2022.01.003.
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Tarasov, Michail V., Polina D. Kotova, Marina F. Bystrova, Natalia V. Kabanova, Veronika Yu Sysoeva, and Stanislav S. Kolesnikov. "Arachidonic acid hyperpolarizes mesenchymal stromal cells from the human adipose tissue by stimulating TREK1 K+ channels." Channels 13, no. 1 (January 1, 2019): 36–47. http://dx.doi.org/10.1080/19336950.2019.1565251.
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Miller, Paula, Chris Peers, and Paul J. Kemp. "Polymodal regulation of hTREK1 by pH, arachidonic acid, and hypoxia: physiological impact in acidosis and alkalosis." American Journal of Physiology-Cell Physiology 286, no. 2 (February 2004): C272—C282. http://dx.doi.org/10.1152/ajpcell.00334.2003.
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Expression of the human tandem P domain K+ channel, hTREK1, is limited almost exclusively to the central nervous system, where ambient Po2 can be as low as 20 Torr. We have previously shown that this level of hypoxia evokes a maximal inhibitory influence on recombinant hTREK1 and occludes the activation by arachidonic acid; this has cast doubt on the idea that TREK1 activation during brain ischemia could facilitate neuroprotection via hyperpolarizing neurons in which it is expressed. Using both whole cell and cell-attached patch-clamp configurations, we now show that the action of another potent TREK activator and ischemia-related event, intracellular acidification, is similarly without effect during compromised O2 availability. This occlusion is observed in either recording condition, and even the concerted actions of both arachidonic acid and intracellular acidosis are unable to activate hTREK1 during hypoxia. Conversely, intracellular alkalinization is a potent channel inhibitor, and hypoxia does not reverse this inhibition. However, increases in intracellular pH are unable to occlude either arachidonic acid activation or hypoxic inhibition. These data highlight two important points. First, during hypoxia, modulation of hTREK1 cannot be accomplished by parameters known to be perturbed in brain ischemia (increased extracellular fatty acids and intracellular acidification). Second, the mechanism of regulation by intracellular alkalinization is distinct from the overlapping structural requirements known to exist for regulation by arachidonic acid, membrane distortion, and acidosis. Thus it seems likely that hTREK1 regulation in the brain will be physiologically more relevant during alkalosis than during ischemia or acidosis.
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Henstock, James R., Michael Rotherham, and Alicia J. El Haj. "Magnetic ion channel activation of TREK1 in human mesenchymal stem cells using nanoparticles promotes osteogenesis in surrounding cells." Journal of Tissue Engineering 9 (January 2018): 204173141880869. http://dx.doi.org/10.1177/2041731418808695.
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Magnetic ion channel activation technology uses superparamagnetic nanoparticles conjugated with targeting antibodies to apply mechanical force directly to stretch-activated ion channels on the cell surface, stimulating mechanotransduction and downstream processes. This technique has been reported to promote differentiation towards musculoskeletal cell types and enhance mineralisation. Previous studies have shown how mesenchymal stem cells injected into a pre-mineralised environment such as a foetal chick epiphysis, results in large-scale osteogenesis at the target site. However, the relative contributions of stem cells and surrounding host tissue has not been resolved, that is, are the mesenchymal stem cells solely responsible for the observed mineralisation or do mechanically stimulated mesenchymal stem cells also promote a host-tissue mineralisation response? To address this, we established a novel two-dimensional co-culture assay, which indicated that magnetic ion channel activation stimulation of human mesenchymal stem cells does not significantly promote migration but does enhance collagen deposition and mineralisation in the surrounding cells. We conclude that one of the important functions of injected human mesenchymal stem cells is to release biological factors (e.g., cytokines and microvesicles) which guide the surrounding tissue response, and that remote control of this signalling process using magnetic ion channel activation technology may be a useful way to both drive and regulate tissue regeneration and healing.
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Nayak, Tapan K., S. Harinath, S. Nama, K. Somasundaram, and S. K. Sikdar. "Inhibition of Human Two-Pore Domain K+ Channel TREK1 by Local Anesthetic Lidocaine: Negative Cooperativity and Half-of-Sites Saturation Kinetics." Molecular Pharmacology 76, no. 4 (July 21, 2009): 903–17. http://dx.doi.org/10.1124/mol.109.056838.
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Woo, JooHan, Young Keul Jeon, Yin-Hua Zhang, Joo Hyun Nam, Dong Hoon Shin, and Sung Joon Kim. "Triple arginine residues in the proximal C-terminus of TREK K+ channels are critical for biphasic regulation by phosphatidylinositol 4,5-bisphosphate." American Journal of Physiology-Cell Physiology 316, no. 3 (March 1, 2019): C312—C324. http://dx.doi.org/10.1152/ajpcell.00417.2018.
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TWIK-related two-pore domain K+ channels (TREKs) are activated by acidic intracellular pH (pHi), membrane stretch, temperature, and arachidonic acid (AA). Phosphatidylinositol 4,5-bisphosphate (PIP2) exerts concentration-dependent biphasic regulations, which have been observed: inhibition by high PIP2, activation by partial decrease of PIP2, and inhibition by depletion of PIP2. Consistently, the stimulation of voltage-sensitive PIP2 phosphatase (Dr-VSP) induces initial activation and subsequent inhibition of TREKs. Lys in the proximal C-terminus (pCt) is responsible for the inhibition by high PIP2, which is generated by phosphatidylinositol kinases with ATP; its neutralizing mutation [K330A of human TREK-2 (hTREK-2)] induces tonic high activity, irrespective of ATP. Here we focus on triple successive Arg in pCt (R3-pCt) as a candidate region for the stimulatory regulation by lower PIP2. Their neutralized mutant (R3A-pCt; RRR340-2A and RRR355-7A in hTREK-1 and -2, respectively) showed negligible basal current and was not affected by ATP removal or by Dr-VSP activation. Phosphatidic acid, a phospholipid agonist of TREKs, did not activate R3A-pCt. In contrast, acidic pHi, AA, and high temperature activated R3A-pCt normally, whereas activation by membrane stretch was attenuated. In hTREK-2, combined neutralizations of the inhibitory K330 and R3-pCt (K330A/RRR355-7A) did not recover the suppressed current. In contrast, combined neutralization of pHi-sensing Glu (E332A/R355-7A) induced tonic high current and no further activation by pHi. Interestingly, when the Gly between K330/E332 and R3-pCt was mutated (G334A), hTREK-2 was tonic activated with reversed responses to ATP and acidic pHi. Therefore, we propose that the PIP2-dependent converse regulation of TREKs by Lys and R3-pCt with Gly implies structural flexibility.
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Jahchan, Nadine, Hanna Ramoth, Vladi Juric, Erin Mayes, Shilpa Mankikar, Ranna Mehta, Mikhail Binnewies, et al. "859 Tuning the tumor microenvironment by reprogramming TREM1+ myeloid cells to unleash anti-tumor immunity in solid tumors." Journal for ImmunoTherapy of Cancer 9, Suppl 2 (November 2021): A900. http://dx.doi.org/10.1136/jitc-2021-sitc2021.859.
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BackgroundThe tumor microenvironment (TME) often contains high levels of suppressive myeloid cells that contribute to innate checkpoint inhibitor (CPI) resistance. Pionyr’s Myeloid Tuning approach involves altering the composition and/or the function of myeloid cells in the TME. Myeloid reprogramming alters the function of immunosuppressive myeloid cells to acquire an immunostimulatory phenotype. Triggering receptor expressed on myeloid cells-1 (TREM1) is an immunoglobulin superfamily cell surface receptor enriched on tumor-associated myeloid cells. To investigate the potential of TREM1 modulation as an anti-cancer therapeutic strategy, Pionyr developed an afucosylated humanized anti-TREM1 monoclonal antibody termed PY159 and characterized it in pre-clinical and translational biomarker assays described below.MethodsPY159 responses in human whole blood and dissociated primary tumor cells in vitro were evaluated by flow cytometry and measurement of secreted cytokines and chemokines by MSD. TREM1 expression in human tumors was validated by scRNAseq, flow cytometry, and immunohistochemistry (IHC). In vivo efficacy and pharmacodynamic studies of a surrogate anti-mouse TREM1 antibody, termed PY159m, were evaluated using syngeneic mouse tumor models, either as a single-agent or in combination with anti-PD-1. To select tumor types and patients most likely to benefit from PY159 therapy, Pionyr developed qualitative and quantitative monoplex and multiplex IHC assays that detect TREM1 expression levels in human tumor tissues.ResultsPY159 treatment in vitro induced signaling, upregulated monocyte activation markers, and induced proinflammatory cytokines. In human tumors, TREM1 was detected on tumor-associated neutrophils, tumor-associated macrophages, and monocytic myeloid-derived suppressive cells. The surrogate PY159m anti-mouse TREM1 antibody exhibited anti-tumor efficacy in several syngeneic mouse tumor models, both as single-agent and in combination with anti-PD-1. Screening for TREM1 expression in tumor tissues demonstrated that TREM1+ tumor associated myeloid cells were highly enriched in the TME of multiple solid tumor indications. The monoplex and multiplex IHC assays offered insights into the localization of TREM1+ myeloid cells and their spatial relationship with other immune cells present in the TME to determine what immune composition will be more favorable for response to PY159 therapy.ConclusionsCollectively, the available nonclinical data support PY159 as a TREM1 agonist that reprograms myeloid cells and unleashes anti-tumor immunity. PY159 safety and efficacy are currently being evaluated in first-in-human clinical trial (NCT04682431) involving select advanced solid tumors patients resistant and refractory to standard of care therapies alone and in combination with a CPI. The TREM1 IHC assay is successfully being used on FFPE archival tumor tissues from enrolled patients to determine TREM1 expression levels.
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Chen, Valerie, Brian Francica, David Hsieh, Dave Freund, Anja Holtz, Saheli Samanta, Jamie Cope, et al. "Abstract 1636: Generation of novel potent human TREX1 inhibitors facilitated by crystallography." Cancer Research 83, no. 7_Supplement (April 4, 2023): 1636. http://dx.doi.org/10.1158/1538-7445.am2023-1636.
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Abstract Background: STING is an innate immune sensor critical for the development of immunity. Tumor cells can inactivate the STING pathway to avoid immune recognition, emphasizing its importance in generating tumor-specific immunity. Broad activation of STING in advanced cancers may be required to initiate CD8+ T cell priming against unique antigenic repertoires among distinct metastases and to reverse an immune-suppressive TME. Due its ubiquitous expression, systemic delivery of untargeted STING agonists may not achieve a therapeutic index. In contrast, expression of the cytosolic DNAse 3’ repair exonuclease (TREX1) is upregulated in tumor cells in response to genomic instability, inflammatory stimuli, and DNA replication, providing an opportunity for selective activation of the STING pathway. In addition to modulating cGAS/STING signaling, interaction with DNA replication enzymes that generate immunogenic DNA waste highlight a facet of TREX1 biology that may inform clinical development of targeted inhibitors. Methods: Using a structure-based drug design strategy, we designed and optimized small-molecule inhibitors of TREX1 with drug-like physicochemical properties that were profiled in biochemical and cell-based assays. X-ray crystallography studies, thermal shift, and biochemical assays were employed to determine mechanism of action. We evaluated the in vivo profile of select compounds. Results: Inhibitors of TREX1 with < 100 µM potency were optimized into a series with nanomolar potency against purified, recombinant murine and human TREX1 protein in biochemical assays. Inhibitors had similar IC50 values against TREX1 nuclease in an intact cell-based assay. Finally, TSA results demonstrated that compound interaction required magnesium. To our knowledge, we produced the first high-resolution co-crystal structures of inhibitor-bound human TREX1. We used this to dissect mouse- and human-specific interactions, confirming MOA predicted by earlier modeling efforts. Lead compounds demonstrated good bioavailability and achieved exposures necessary for target engagement in mouse models and resulted in tumor growth inhibition when combined with sub-therapeutic doses of doxorubicin. Conclusions: We present the identification and characterization of a potential first-in-class TREX1 inhibitor with nanomolar potency against human and mouse TREX1. Treatment with TREX1 inhibitors conferred profound anti-tumor activity when combined with DNA-damaging agents. Here we demonstrate that targeting TREX1 can specifically and locally engage the STING pathway in the tumor microenvironment, enhance tumor-specific immunity, and provide therapeutic benefit. Citation Format: Valerie Chen, Brian Francica, David Hsieh, Dave Freund, Anja Holtz, Saheli Samanta, Jamie Cope, Ryan Clark, Peppi Prasit, Anne Moon, Henry Johnson, Thomas Dubensky, Dara Burdette. Generation of novel potent human TREX1 inhibitors facilitated by crystallography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1636.
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Salojin, Costa, Anna Gardberg, Valerie Vivat, Lei Cui, Jeffrey Lauer, Nico Cantone, Jacob Stuckey, et al. "765 The first-in-class small molecule TREX1 inhibitor CPI-381 demonstrates type I IFN induction and sensitization of tumors to immune checkpoint blockade." Journal for ImmunoTherapy of Cancer 9, Suppl 2 (November 2021): A800. http://dx.doi.org/10.1136/jitc-2021-sitc2021.765.
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BackgroundTREX1 is an exonuclease that functions as a negative regulator of innate immunity. TREX1 controls dsDNA sensing in tumor and immune cells by preventing aberrant dsDNA buildup that triggers STING-mediated Type 1 Interferon (IFN) induction leading to priming of the adaptive immune system. Loss of function mutations in TREX1 and genetic ablation of trex1 in mice lead to induction of IFNbeta-driven autoimmunity. Thus, TREX1 is a promising target to elicit IFN-mediated anti-tumor immunity.MethodsTo characterize TREX1 inhibitors we developed cell-based assays utilizing human HCT116 carcinoma and THP-1 monocytic Dual reporter cell lines to monitor IRF activity. Activation of cGAS was assessed by measuring cGAMP levels in B16F10 melanoma cells. The potency of TREX1 inhibitors in primary human dendritic cells (DC)s was analyzed by measuring IFNbeta induction by exogenous dsDNA. Analysis of tumor growth inhibition following TREX1 inhibitor treatment was conducted in mouse syngeneic tumor models. TREX1 activity was assessed by measuring degradation of a custom dsDNA substrate.ResultsWe report here the development of a small molecule TREX1 inhibitor, CPI-381, with nanomolar cellular potency, which translated into a robust induction of IRF reporter activity. We observed a significant increase in cGAMP production in B16F10 cells transfected with DNA in the presence of CPI-381, suggesting that CPI-381-mediated inhibition of TREX1 leads to the activation of dsDNA sensors, such as cGAS. Treatment of THP-1 cells with CPI-381 induced the expression of several key ISG involved in innate immunity. Moreover, inhibition of TREX1 with CPI-381 phenocopied the effect of TREX1 genetic deletion in primary human DCs by upregulating IFNbeta. To evaluate whether TREX1 negatively regulates IFNbeta production in syngeneic tumor models, we knocked down trex1 in B16F10, MB49, MC38, and CT26 murine cells. Accumulation of cytosolic dsDNA resulted in a substantial increase in IFNbeta secretion by all four TREX1-KO cell lines.In vivo efficacy studies with CPI-381 demonstrated reduced tumor growth in the MC38 syngeneic tumor model either alone or in combination with anti-PD1. We observed a reduction of TREX1 activity in CPI-381 treated tumors, confirming an inverse relationship between TREX1 intra-tumor activity and tumor growth, and efficient target engagement after systemic (oral) delivery.ConclusionsWe have developed a first-in-class, potent TREX1 inhibitor demonstrating excellent in vitro and in vivo potency via enhancement of cytosolic dsDNA sensing and induction of IFNbeta in cancer and immune cells. CPI-381-induced tumor-intrinsic TREX1 inhibition elicits antitumor immunity as a single agent and increases response to immune checkpoint blockade via mechanisms downstream of TREX1 that activate type I IFN signaling.Ethics ApprovalAll animal work was approved and conducted under the oversight of the Charles River Accelerator and Development Lab (CRADL, Cambridge, MA) Institutional Animal Care and Use Committee (protocol # 2021-1258).
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Grieves, Jessica L., Jason M. Fye, Scott Harvey, Jason M. Grayson, Thomas Hollis, and Fred W. Perrino. "Exonuclease TREX1 degrades double-stranded DNA to prevent spontaneous lupus-like inflammatory disease." Proceedings of the National Academy of Sciences 112, no. 16 (April 6, 2015): 5117–22. http://dx.doi.org/10.1073/pnas.1423804112.
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The TREX1 gene encodes a potent DNA exonuclease, and mutations in TREX1 cause a spectrum of lupus-like autoimmune diseases. Most lupus patients develop autoantibodies to double-stranded DNA (dsDNA), but the source of DNA antigen is unknown. The TREX1 D18N mutation causes a monogenic, cutaneous form of lupus called familial chilblain lupus, and the TREX1 D18N enzyme exhibits dysfunctional dsDNA-degrading activity, providing a link between dsDNA degradation and nucleic acid-mediated autoimmune disease. We determined the structure of the TREX1 D18N protein in complex with dsDNA, revealing how this exonuclease uses a novel DNA-unwinding mechanism to separate the polynucleotide strands for single-stranded DNA (ssDNA) loading into the active site. The TREX1 D18N dsDNA interactions coupled with catalytic deficiency explain how this mutant nuclease prevents dsDNA degradation. We tested the effects of TREX1 D18N in vivo by replacing the TREX1 WT gene in mice with the TREX1 D18N allele. The TREX1 D18N mice exhibit systemic inflammation, lymphoid hyperplasia, vasculitis, and kidney disease. The observed lupus-like inflammatory disease is associated with immune activation, production of autoantibodies to dsDNA, and deposition of immune complexes in the kidney. Thus, dysfunctional dsDNA degradation by TREX1 D18N induces disease in mice that recapitulates many characteristics of human lupus. Failure to clear DNA has long been linked to lupus in humans, and these data point to dsDNA as a key substrate for TREX1 and a major antigen source in mice with dysfunctional TREX1 enzyme.
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Pineda, Ricardo H., Balachandar Nedumaran, Joseph Hypolite, Xiao-Qing Pan, Shandra Wilson, Randall B. Meacham, and Anna P. Malykhina. "Altered expression and modulation of the two-pore-domain (K2P) mechanogated potassium channel TREK-1 in overactive human detrusor." American Journal of Physiology-Renal Physiology 313, no. 2 (August 1, 2017): F535—F546. http://dx.doi.org/10.1152/ajprenal.00638.2016.
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Detrusor overactivity (DO) is the abnormal response of the urinary bladder to physiological stretch during the filling phase of the micturition cycle. The mechanisms of bladder smooth muscle compliance upon the wall stretch are poorly understood. We previously reported that the function of normal detrusor is regulated by TREK-1, a member of the mechanogated subfamily of two-pore-domain potassium (K2P) channels. In the present study, we aimed to identify the changes in expression and function of TREK-1 channels under pathological conditions associated with DO, evaluate the potential relationship between TREK-1 channels and cytoskeletal proteins in the human bladder, and test the possibility of modulation of TREK-1 channel expression by small RNAs. Expression of TREK-1 channels in DO specimens was 2.7-fold decreased compared with control bladders and was associated with a significant reduction of the recorded TREK-1 currents. Isolated DO muscle strips failed to relax when exposed to a TREK-1 channel opener. Immunocytochemical labeling revealed close association of TREK-1 channels with cell cytoskeletal proteins and caveolins, with caveolae microdomains being severely disrupted in DO specimens. Small activating RNA (saRNA) tested in vitro provided evidence that expression of TREK-1 protein could be partially upregulated. Our data confirmed a significant downregulation of TREK-1 expression in human DO specimens and provided evidence of close association between the channel, cell cytoskeleton, and caveolins. Upregulation of TREK-1 expression by saRNA could be a future step for the development of in vivo pharmacological and genetic approaches to treat DO in humans.
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Schwingshackl, Andreas, Bin Teng, Manik Ghosh, Keng Gat Lim, Gabor Tigyi, Damodaran Narayanan, Jonathan H. Jaggar, and Christopher M. Waters. "Regulation of interleukin-6 secretion by the two-pore-domain potassium channel Trek-1 in alveolar epithelial cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 304, no. 4 (February 15, 2013): L276—L286. http://dx.doi.org/10.1152/ajplung.00299.2012.
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We recently proposed a role for the two-pore-domain K+ (K2P) channel Trek-1 in the regulation of cytokine release from mouse alveolar epithelial cells (AECs) by demonstrating decreased interleukin-6 (IL-6) secretion from Trek-1-deficient cells, but the underlying mechanisms remained unknown. This study was designed to investigate the mechanisms by which Trek-1 decreases IL-6 secretion. We hypothesized that Trek-1 regulates tumor necrosis factor-α (TNF-α)-induced IL-6 release via NF-κB-, p38-, and PKC-dependent pathways. We found that Trek-1 deficiency decreased IL-6 secretion from mouse and human AECs at both transcriptional and translational levels. While NF-κB/p65 phosphorylation was unchanged, p38 phosphorylation was decreased in Trek-1-deficient cells, and pharmacological inhibition of p38 decreased IL-6 secretion in control but not Trek-1-deficient cells. Similarly, pharmacological inhibition of PKC also decreased IL-6 release, and we found decreased phosphorylation of the isoforms PKC/PKDμ (Ser744/748), PKCθ, PKCδ, PKCα/βII, and PKCζ/λ, but not PKC/PKDμ (Ser916) in Trek-1-deficient AECs. Phosphorylation of PKCθ, a Ca2+-independent isoform, was intact in control cells but impaired in Trek-1-deficient cells. Furthermore, TNF-α did not elevate the intracellular Ca2+ concentration in control or Trek-1-deficient cells, and removal of extracellular Ca2+ did not impair IL-6 release. In summary, we report the expression of Trek-1 in human AECs and propose that Trek-1 deficiency may alter both IL-6 translation and transcription in AECs without affecting Ca2+ signaling. The results of this study identify Trek-1 as a new potential target for the development of novel treatment strategies against acute lung injury.
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Tao, Sha-Sha, Guo-Cui Wu, Qin Zhang, Tian-Ping Zhang, Rui-Xue Leng, Hai-Feng Pan, and Dong-Qing Ye. "TREX1 As a Potential Therapeutic Target for Autoimmune and Inflammatory Diseases." Current Pharmaceutical Design 25, no. 30 (November 13, 2019): 3239–47. http://dx.doi.org/10.2174/1381612825666190902113218.
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Background and Objectives: The 3’ repair exonuclease 1 (TREX1) gene is the major DNA-specific 3’–5 ’exonuclease of mammalian cells which reduces single- and double-stranded DNA (ssDNA and dsDNA) to prevent undue immune activation mediated by the nucleic acid. TREX1 is also a crucial suppressor of selfrecognition that protects the host from inappropriate autoimmune activations. It has been revealed that TREX1 function is necessary to prevent host DNA accumulating after cell death which could actuate an autoimmune response. In the manuscript, we will discuss in detail the latest advancement to study the role of TREX1 in autoimmune disease. Methods: As a pivotal cytoprotective, antioxidant, anti-apoptotic, immunosuppressive, as well as an antiinflammatory molecule, the functional mechanisms of TREX1 were multifactorial. In this review, we will briefly summarize the latest advancement in studying the role of TREX1 in autoimmune disease, and discuss its potential as a therapeutic target for these diseases. Results: Deficiency of TREX1 in human patients and murine models is characterized by systemic inflammation and the disorder of TREX1 functions drives inflammatory responses leading to autoimmune disease. Moreover, much more studies revealed that mutations in TREX1 have been associated with a range of autoimmune disorders. But it is also unclear whether the mutations of TREX1 play a causal role in the disease progression, and whether manipulation of TREX1 has a beneficial effect in the treatment of autoimmune diseases. Conclusion: Integration of functional TREX1 biology into autoimmune diseases may further deepen our understanding of the development and pathogenesis of autoimmune diseases and provide new clues and evidence for the treatment of autoimmune diseases.
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Lindahl, Tomas, Deborah E. Barnes, Yun-Gui Yang, and Peter Robins. "Biochemical properties of mammalian TREX1 and its association with DNA replication and inherited inflammatory disease." Biochemical Society Transactions 37, no. 3 (May 20, 2009): 535–38. http://dx.doi.org/10.1042/bst0370535.
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The major DNA-specific 3′–5′ exonuclease of mammalian cells is TREX1 (3′ repair exonuclease 1; previously called DNase III). The human enzyme is encoded by a single exon and, like many 3′ exonucleases, exists as a homodimer. TREX1 degrades ssDNA (single-stranded DNA) more efficiently than dsDNA (double-stranded DNA), and its catalytic properties are similar to those of Escherichia coli exonuclease X. However, TREX1 is only found in mammals and has an extended C-terminal domain containing a leucine-rich sequence required for its association with the endoplasmic reticulum. In normal S-phase and also in response to genotoxic stress, TREX1 at least partly redistributes to the cell nucleus. In a collaborative project, we have demonstrated TREX1 enzyme deficiency in Aicardi–Goutières syndrome. Subsequently, we have shown that AGS1 cells exhibit chronic ATM (ataxia telangiectasia mutated)-dependent checkpoint activation, and these TREX1-deficient cells accumulate ssDNA fragments of a distinct size generated during DNA replication. Other groups have shown that the syndromes of familial chilblain lupus as well as systemic lupus erythematosus, and the distinct neurovascular disorder retinal vasculopathy with cerebral leukodystrophy, can be caused by dominant mutations at different sites within the TREX1 gene.
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Francica, Brian, Dara Burdette, Ryan Clark, Jamie Cope, David Freund, Anja Holtz, Peppi Prasit, Chan Whiting, and Thomas W. Dubensky. "Abstract 2075: Systemic small molecule TREX1 inhibitors to selectively activate STING in the TME of metastatic disease." Cancer Research 82, no. 12_Supplement (June 15, 2022): 2075. http://dx.doi.org/10.1158/1538-7445.am2022-2075.
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Abstract Genetic evidence from human disease and mouse genetic knock-out studies identify the Stimulator of Interferon Genes (STING) pathway as a critical innate immune sensor for the development of immunity. Tumor cells can evolve to avoid immune recognition through inactivating the STING pathway by diverse mechanisms, indicating that it is important to generating tumor-specific immunity. However, the clinical activity of STING agonists given by intratumoral (IT) administration has not compared well to preclinical studies. The scientific hypothesis supporting these first clinical studies is that localized CD8+ T cell priming would have activity against distal non-injected tumors, but findings that tumors in advanced malignancies have unique antigenic repertoires suggests that this approach may have limited activity against distal tumors. Global innate activation in metastases may therefore be necessary to prime a broadly active CD8+ T cell population targeting diverse antigens, in addition having the benefit of reversing the immune suppressive tumor microenvironment (TME). However, ubiquitous expression of STING presents a significant challenge to achieving a therapeutic index with systemic delivery of direct STING agonists. Selective activation of the STING pathway may be achieved through targeted inhibition of TREX1, a cytosolic DNA exonuclease that modulates cGAS/STING signaling. Expression of TREX1, in contrast to STING, is increased in tumor cells due to elevated levels of cytosolic DNA resulting from genetic instability, DNA repair mutation, inflammatory mediators or DNA-modifying anti-cancer therapies. These observations provide the principal scientific rationale to selectively activate the STING pathway in metastatic disease through targeted inhibition of TREX1. Utilizing published TREX1 X-ray crystal structures to guide medicinal chemistry, we discovered small molecule inhibitors of TREX1 and transformed these molecules from >100 µM leads into a series with drug-like physicochemical properties and picomolar potency against both human and mouse TREX1. We evaluated the activity of lead molecules in cell-based assays, in which TREX1 inhibition enhanced cGAS/STING signaling, and advanced molecules with desired pharmacokinetic profiles to mouse tumor studies. We observed significant anti-tumor activity in mice with CT26 tumors given a combined therapy of low dose doxorubicin to induce dsDNA breaks and increase TME TREX1 expression along with lead series TREX1 molecule inhibitors. Recognizing that TREX1 is a DNA repair enzyme, we also showed that TREX1 inhibitors were cytotoxic in DNA repair deficient human tumor cell lines, informing advancement of this new class of STING therapeutics as a clinical approach to both activate the cGAS/STING pathway to initiate immune recognition, as well as to inhibit DNA repair orthogonal to existing tumor-driver DNA repair mutations. Citation Format: Brian Francica, Dara Burdette, Ryan Clark, Jamie Cope, David Freund, Anja Holtz, Peppi Prasit, Chan Whiting, Thomas W. Dubensky. Systemic small molecule TREX1 inhibitors to selectively activate STING in the TME of metastatic disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2075.
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Brenner, Tanja, and Kevin M. O'Shaughnessy. "Both TASK-3 and TREK-1 two-pore loop K channels are expressed in H295R cells and modulate their membrane potential and aldosterone secretion." American Journal of Physiology-Endocrinology and Metabolism 295, no. 6 (December 2008): E1480—E1486. http://dx.doi.org/10.1152/ajpendo.90652.2008.
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The rate of aldosterone synthesis by adrenal glomerulosa cells relies on the selective permeability of the glomerulosa cell to K+ ions. In rodent and bovine adrenal glomerulosa cells, this background potassium current is provided by a two-pore loop potassium (K2P) channel: largely TASK-3 in the rat and TREK-1 in the cow. The nature of the K2P channel in the human adrenal cortex is not known, and we have addressed this issue here using the H295R human adrenal cell line. We show that these cells express mRNA and protein for both TASK-3 and TREK-1 K2P channels. Using a potentiometric dye (FMP), we also show that TASK-3 and TREK-1 channel modulators can affect the membrane potential of H295R cells. Transfecting H295R cells with TASK-3 or TREK-1 dominant-negative mutants (TASK-3 G95E or TREK-1 G144E) produced depolarization of H295R cells and altered K-stimulated aldosterone secretion. Finally, transfection of a constitutively active mutant of Gαq into H295R cells (GTPase-deficient Gαq-QL) depolarized them and increased basal aldosterone secretion. Taken together, our data support both TASK-3 and TREK-1 as being functionally operational in the H295R cell line. This suggests that human adrenal glomerulosa cells may utilize both of these K2P channels for their background potassium current.
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Pike, Ashley, Yin Dong, Alexandra Mackenzie, Conor McClenaghan, Shubhashish Mukhopadhyay, Nicola Burgess-Brown, Stephen Tucker, and Elisabeth Carpenter. "Structures of the human two-pore domain potassium channels TREK-1 and TREK-2." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1489. http://dx.doi.org/10.1107/s2053273314085106.
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TREK-1/2 are members of the mechano-gated subfamily of two-pore (K2P) domain potassium channels leaking K+ out of the cell and contributing to the resting membrane potential. In contrast to the classical tetrameric potassium channels, K2P channels are dimeric with an atypical architecture and the structural mechanisms underlying their channel gating are poorly understood. Here we present the crystal structures of human TREK-1 and TREK-2 at resolutions of 2.7 and 3.4Å which provide insights into the basis of intracellular and extracellular gating in this unique family of ion channels. We have solved the structure of TREK-2 in two distinct conformations differing in the orientation of the pore-lining transmembrane helices. The C-terminal M4 helix is hinged at a conserved glycine residue so that it adopts one of two distinct orientations. The M4 helix is either kinked towards the membrane, packing against the M2 inner helix of the adjacent subunit ("M4 up") or straightens and interacts with the M2/M3 helices from the same subunit ("M4 down"). In the M4 down state, a hydrophobic lateral opening runs perpendicular to the ion conductance pathway between M2 and M4 and links the inner vestibule to the membrane-exposed face of the channel. Transition between the "M4 down" and "M4 up" conformations may play a role in channel activation and gating. Cocrystallisation with a TREK-1/2 channel inhibitor promotes the "M4 down" state. The structure of TREK-1 exhibits an "M4-up" conformation but is unusual in that the selectivity filter is significantly distorted with only two correctly-formed potassium sites. The structure also reveals a divalent ion binding site between the extracellular cap and the pore domain loop. The TREK-1 structure illustrates how changes at an extracellular site can affect the pore structure. The structures will be described in detail along with their implications for channel gating in response to intracellular and extracellular stimuli.
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Gao, Daxing, Tuo Li, Xiao-Dong Li, Xiang Chen, Quan-Zhen Li, Mary Wight-Carter, and Zhijian J. Chen. "Activation of cyclic GMP-AMP synthase by self-DNA causes autoimmune diseases." Proceedings of the National Academy of Sciences 112, no. 42 (September 14, 2015): E5699—E5705. http://dx.doi.org/10.1073/pnas.1516465112.
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TREX1 is an exonuclease that digests DNA in the cytoplasm. Loss-of-function mutations of TREX1 are linked to Aicardi–Goutieres Syndrome (AGS) and systemic lupus erythematosus (SLE) in humans. Trex1−/− mice exhibit autoimmune and inflammatory phenotypes that are associated with elevated expression of interferon (IFN)-induced genes (ISGs). Cyclic GMP-AMP (cGAMP) synthase (cGAS) is a cytosolic DNA sensor that activates the IFN pathway. Upon binding to DNA, cGAS is activated to catalyze the synthesis of cGAMP, which functions as a second messenger that binds and activates the adaptor protein STING to induce IFNs and other cytokines. Here we show that genetic ablation of cGas in Trex1−/− mice eliminated all detectable pathological and molecular phenotypes, including ISG induction, autoantibody production, aberrant T-cell activation, and lethality. Even deletion of just one allele of cGas largely rescued the phenotypes of Trex1−/− mice. Similarly, deletion of cGas in mice lacking DNaseII, a lysosomal enzyme that digests DNA, rescued the lethal autoimmune phenotypes of the DNaseII−/− mice. Through quantitative mass spectrometry, we found that cGAMP accumulated in mouse tissues deficient in Trex1 or DNaseII and that this accumulation was dependent on cGAS. These results demonstrate that cGAS activation causes the autoimmune diseases in Trex1−/− and DNaseII−/− mice and suggest that inhibition of cGAS may lead to prevention and treatment of some human autoimmune diseases caused by self-DNA.
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Miyazaki, Takuya, Yong-Soo Kim, Jeong-Heon Yoon, Hongsheng Wang, and Herbert C. Morse. "The 3'-5' Exonuclease, TREX1, Interacts with Poly(ADP-ribose) Polymerase-1 (PARP1) in Response to DNA Damage." Blood 120, no. 21 (November 16, 2012): 1046. http://dx.doi.org/10.1182/blood.v120.21.1046.1046.
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Abstract Abstract 1046 Background: Recognition of nucleic acids plays a key role in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE). The major 3'-5' DNA exonuclease, TREX1, degrades single- and double-stranded DNA to minimize potential immune activation by persistent self or retroelement DNA. Mutations in the human TREX1gene have been linked to four diseases: SLE; Aicardi-Goutières syndrome (AGS); retinal vasculopathy and cerebral leukodystrophy (RVCL); and familial chilblain lupus (CBL). SLE, AGS and CBL have overlapping features characterized by expression of interferon-alpha and autoantibody production, but are distinct clinical conditions. RVCL is a non-inflammatory endotheliopathy. Methods: As part of our efforts to determine the molecular mechanisms underlying TREX1 involvement in the pathogenesis of these diseases, we identified a novel TREX1-binding partner protein by Mass Spectrometry and Co-Immunoprecipitation (Co-IP) assays. We examined the interaction domains and the effects of mutations in TREX1 associated with these diseases. Results: We found that TREX1 interacted with poly(ADP-ribose) polymerase-1 (PARP1), a nuclear DNA repair enzyme involved in the DNA damage response. The interaction domain of PARP1 was mapped to the amino-terminal zinc finger domains. Subcellular localization analysis showed that TREX1 normally localized to the cytoplasm and cytomembranes, but translocated to the nucleus (with some bound to chromatin) in response to sublethal DNA damage. Co-IP assays revealed that the interaction was increased following DNA damage in concert with the post-translational PARlation of PARP1. Functional studies showed that TREX1 induced the PARlation of PARP1 in a TREX1 dose-dependent manner. Furthermore, siRNA knockdown of TREX1 promoted PARP1 cleavage and loss of PARP1 enzymatic activity, resulting in the induction of apoptosis. We further analyzed the effects of TREX1-PARP1 interaction in relation to the pathogenesis of AGS or RVCL. Co-IP assays revealed that the RVCL-related TREX1-mutant protein, V235fs, bound to PARP1 as well as wild-type TREX1, whereas the AGS-related R114H mutant protein did not bind PARP1. Conclusion: These findings demonstrate that TREX1 contributes to the regulation of PARP1 in the DNA damage response and that mutation-induced alterations in the function of TREX1 may be a factor in the development or progression of these autoimmune diseases by affecting PARP1 activity. Disclosures: No relevant conflicts of interest to declare.
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Shuey, Megan M., Rachel R. Xiang, M. Elizabeth Moss, Brigett V. Carvajal, Yihua Wang, Nicholas Camarda, Daniel Fabbri, et al. "Systems Approach to Integrating Preclinical Apolipoprotein E-Knockout Investigations Reveals Novel Etiologic Pathways and Master Atherosclerosis Network in Humans." Arteriosclerosis, Thrombosis, and Vascular Biology 42, no. 1 (January 2022): 35–48. http://dx.doi.org/10.1161/atvbaha.121.317071.
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Objective: Animal models of atherosclerosis are used extensively to interrogate molecular mechanisms in serial fashion. We tested whether a novel systems biology approach to integration of preclinical data identifies novel pathways and regulators in human disease. Approach and Results: Of 716 articles published in ATVB from 1995 to 2019 using the apolipoprotein E knockout mouse to study atherosclerosis, data were extracted from 360 unique studies in which a gene was experimentally perturbed to impact plaque size or composition and analyzed using Ingenuity Pathway Analysis software. TREM1 (triggering receptor expressed on myeloid cells) signaling and LXR/RXR (liver X receptor/retinoid X receptor) activation were identified as the top atherosclerosis-associated pathways in mice (both P <1.93×10 − 4 , TREM1 implicated early and LXR/RXR in late atherogenesis). The top upstream regulatory network in mice (sc-58125, a COX2 inhibitor) linked 64.0% of the genes into a single network. The pathways and networks identified in mice were interrogated by testing for associations between the genetically predicted gene expression of each mouse pathway-identified human homolog with clinical atherosclerosis in a cohort of 88 660 human subjects. Homologous human pathways and networks were significantly enriched for gene-atherosclerosis associations (empirical P <0.01 for TREM1 and LXR/RXR pathways and COX2 network). This included 12(60.0%) TREM1 pathway genes, 15(53.6%) LXR/RXR pathway genes, and 67(49.3%) COX2 network genes. Mouse analyses predicted, and human study validated, the strong association of COX2 expression ( PTGS2 ) with increased likelihood of atherosclerosis (odds ratio, 1.68 per SD of genetically predicted gene expression; P =1.07×10 − 6 ). Conclusions: PRESCIANT (Preclinical Science Integration and Translation) leverages published preclinical investigations to identify high-confidence pathways, networks, and regulators of human disease.
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Roche, Chris. "‘The Fertile Brain and Inventive Power of Man’: Anthropogenic Factors in the Cessation of Springbok Treks and the Disruption of the Karoo Ecosystem, 1865–1908." Africa 78, no. 2 (May 2008): 157–88. http://dx.doi.org/10.3366/e0001972008000120.
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The demise of springbok treks, the irruptive migration patterns of the species in South Africa's Karoo region, has long been attributed to the rinderpest epizootic understood to have coincided in both time and space with the last of the great springbok treks. This is incorrect. Instead the cessation of springbok treks can be attributed to a variety of anthropogenic factors. This article first examines and then rejects the case for rinderpest, before introducing alternative causal factors such as the increase in livestock and human populations, the effects of fencing and the double impact of hunting and concomitant drought. These factors, it is argued, acted in concert to effectively remove the conditions necessary for springbok treks and thereby end the phenomenon. It is suggested that the local extinction of this phenomenon – a keystone species and process – is an important and heretofore unconsidered element in the decline of the Karoo ecosystem.
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Francis, Abbie, Erika Bosio, Shelley F. Stone, Daniel M. Fatovich, Glenn Arendts, Stephen P. J. MacDonald, Sally Burrows, and Simon G. A. Brown. "Markers Involved in Innate Immunity and Neutrophil Activation are Elevated during Acute Human Anaphylaxis: Validation of a Microarray Study." Journal of Innate Immunity 11, no. 1 (September 6, 2018): 63–73. http://dx.doi.org/10.1159/000492301.
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Background: We have previously identified the upregulation of the innate immune response, neutrophil activation, and apoptosis during anaphylaxis using a microarray approach. This study aimed to validate the differential gene expression and investigate protein concentrations of “hub genes” and upstream regulators during anaphylaxis. Methods: Samples were collected from patients with anaphylaxis on their arrival at the emergency department, and after 1 and 3 h. mRNA levels of 11 genes (interleukin-6 [IL-6], IL-10, oncostatin M [OSM], S100A8, S100A9, matrix metalloproteinase 9 [MMP9], FASL, toll-like receptor 4 [TLR4], MYD88, triggering receptor expressed on myeloid cells 1 [TREM1], and cluster of differentiation 64 [CD64]) were measured in peripheral blood leucocytes using qPCR. Serum protein concentrations were measured by ELISA or cytometric bead array for 6 of these candidates. Results: Of 69 anaphylaxis patients enrolled, 36 (52%) had severe reactions, and 38 (55%) were female. Increases in both mRNA and protein of IL-10, S100A9, MMP9, and TREM1 were observed. OSM, S100A8, TLR4, and CD64 were upregulated and IL-6 protein concentrations were increased during anaphylaxis. Both FASL and soluble Fas ligand decreased during anaphylaxis. Conclusion: These results provide evidence for the involvement of innate immune pathways and myeloid cells during human anaphylaxis, validating previous microarray findings. Elevated S100A8, S100A9, TLR4, and TREM1 expression, and increased S100A9 and soluble TREM1 protein concentrations strongly suggest that neutrophils are activated during acute anaphylaxis.
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Enyeart, John J., and Judith A. Enyeart. "Ca2+ and K+ channels of normal human adrenal zona fasciculata cells: Properties and modulation by ACTH and AngII." Journal of General Physiology 142, no. 2 (July 15, 2013): 137–55. http://dx.doi.org/10.1085/jgp.201310964.
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In whole cell patch clamp recordings, we found that normal human adrenal zona fasciculata (AZF) cells express voltage-gated, rapidly inactivating Ca2+ and K+ currents and a noninactivating, leak-type K+ current. Characterization of these currents with respect to voltage-dependent gating and kinetic properties, pharmacology, and modulation by the peptide hormones adrenocorticotropic hormone (ACTH) and AngII, in conjunction with Northern blot analysis, identified these channels as Cav3.2 (encoded by CACNA1H), Kv1.4 (KCNA4), and TREK-1 (KCNK2). In particular, the low voltage–activated, rapidly inactivating and slowly deactivating Ca2+ current (Cav3.2) was potently blocked by Ni2+ with an IC50 of 3 µM. The voltage-gated, rapidly inactivating K+ current (Kv1.4) was robustly expressed in nearly every cell, with a current density of 95.0 ± 7.2 pA/pF (n = 64). The noninactivating, outwardly rectifying K+ current (TREK-1) grew to a stable maximum over a period of minutes when recording at a holding potential of −80 mV. This noninactivating K+ current was markedly activated by cinnamyl 1-3,4-dihydroxy-α-cyanocinnamate (CDC) and arachidonic acid (AA) and inhibited almost completely by forskolin, properties which are specific to TREK-1 among the K2P family of K+ channels. The activation of TREK-1 by AA and inhibition by forskolin were closely linked to membrane hyperpolarization and depolarization, respectively. ACTH and AngII selectively inhibited the noninactivating K+ current in human AZF cells at concentrations that stimulated cortisol secretion. Accordingly, mibefradil and CDC at concentrations that, respectively, blocked Cav3.2 and activated TREK-1, each inhibited both ACTH- and AngII-stimulated cortisol secretion. These results characterize the major Ca2+ and K+ channels expressed by normal human AZF cells and identify TREK-1 as the primary leak-type channel involved in establishing the membrane potential. These findings also suggest a model for cortisol secretion in human AZF cells wherein ACTH and AngII receptor activation is coupled to membrane depolarization and the activation of Cav3.2 channels through inhibition of hTREK-1.
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Rice, Gillian I., Mathieu P. Rodero, and Yanick J. Crow. "Human Disease Phenotypes Associated With Mutations in TREX1." Journal of Clinical Immunology 35, no. 3 (March 4, 2015): 235–43. http://dx.doi.org/10.1007/s10875-015-0147-3.
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Rivera, Fernando A., Ming-Mei Liu, Sue Vanek, Agnes Burris, and Joseph P. Minei. "QS393. TREM1 Mediates Activation of Human Endothelial Cells." Journal of Surgical Research 144, no. 2 (February 2008): 424. http://dx.doi.org/10.1016/j.jss.2007.12.647.
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Yarishkin, Oleg, Tam T. T. Phuong, Colin A. Bretz, Kenneth W. Olsen, Jackson M. Baumann, Monika Lakk, Alan Crandall, Catherine Heurteaux, Mary E. Hartnett, and David Križaj. "TREK-1 channels regulate pressure sensitivity and calcium signaling in trabecular meshwork cells." Journal of General Physiology 150, no. 12 (November 16, 2018): 1660–75. http://dx.doi.org/10.1085/jgp.201812179.
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Mechanotransduction by the trabecular meshwork (TM) is an essential component of intraocular pressure regulation in the vertebrate eye. This process is compromised in glaucoma but is poorly understood. In this study, we identify transient receptor potential vanilloid isoform 4 (TRPV4) and TWIK-related potassium channel-1 (TREK-1) as key molecular determinants of TM membrane potential, pressure sensitivity, calcium homeostasis, and transcellular permeability. We show that resting membrane potential in human TM cells is unaffected by “classical” inhibitors of voltage-activated, calcium-activated, and inwardly rectifying potassium channels but is depolarized by blockers of tandem-pore K+ channels. Using gene profiling, we reveal the presence of TREK-1, TASK-1, TWIK-2, and THIK transcripts in TM cells. Pressure stimuli, arachidonic acid, and TREK-1 activators hyperpolarize these cells, effects that are antagonized by quinine, amlodipine, spadin, and short-hairpin RNA–mediated knockdown of TREK-1 but not TASK-1. Activation and inhibition of TREK-1 modulates [Ca2+]TM and lowers the impedance of cell monolayers. Together, these results suggest that tensile homeostasis in the TM may be regulated by balanced, pressure-dependent activation of TRPV4 and TREK-1 mechanotransducers.
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Hur, C. G., D. Kang, J. Y. Park, S. G. Hong, and J. Han. "269 EXPRESSION OF TANDEM-PORE DOMAIN K+ CHANNELS IN BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS." Reproduction, Fertility and Development 19, no. 1 (2007): 251. http://dx.doi.org/10.1071/rdv19n1ab269.
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Tandem-pore domain K+ (K2P) channels that contribute to setting the resting membrane potential of excitable and nonexcitable cells are expressed in many kinds of cells and tissues. Recent studies have shown that TASK [TWIK (Tandem of P domains in Weak Inward rectifying K+ channels)-related acid-sensitive K+ channels] and TREK (TWIK-Related K+ channels), members of K2P channel family that are involved in a variety of cellular functions, are expressed in human myometrium, placenta, and cytotrophoblast cells. However, their expression in bovine oocytes and embryos has not yet been reported. In this study, we examined whether TASK and TREK channels are expressed in bovine immature (germinal vesicle-stage) and mature (metaphase II-stage) oocytes and in pre-implantation (2-cell- and 16-cell-stage) embryos using RT-PCR and immunocytochemistry. RT-PCR data showed that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK channels were expressed in bovine immature and mature oocytes. Interestingly, the expression levels of TREK channels were 2-fold higher than those of TASK channels as judged by semiquantitative RT-PCR and real-time PCR with cDNA synthesized from 50 individual immature and mature oocytes (P < 0.05, n = 4). Intensity of genes was normalized with respect to that of GAPDH. Consistent with RT-PCR data, immunocytochemical data showed that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK channels were expressed in bovine immature and mature oocytes. The fluorescence intensity of TREK channels was higher than that of TASK channels (P < 0.05, n = 5). TASK and TREK channels were also expressed in pre-implantation embryos. Of TREK channels, the TREK-2 channel was strongly expressed in immature and mature oocytes and in pre-implantation embryos (P < 0.05, n = 5). For statistics, Student's t-test was used, with P < 0.05 as the criterion for significance. Our results show that TASK-1, TASK-3, TREK-1, TREK-2, and TRAAK channels were expressed in bovine immature and mature oocytes and pre-implantation embryos. These results suggest that TASK and TREK channels could be involved in various physiological processes in mammalian oocytes and embryos.
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Vylkova, Slavena, Xuewei S. Li, Jennifer C. Berner, and Mira Edgerton. "Distinct Antifungal Mechanisms: β-Defensins Require Candida albicans Ssa1 Protein, while Trk1p Mediates Activity of Cysteine-Free Cationic Peptides." Antimicrobial Agents and Chemotherapy 50, no. 1 (January 2006): 324–31. http://dx.doi.org/10.1128/aac.50.1.324-331.2006.
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ABSTRACT Salivary histatin 5 (Hst 5) kills the fungal pathogen Candida albicans via a multistep process which includes binding to Ssa1/2 proteins on the cell surface and requires the TRK1 potassium transporter. Hst 5-induced membrane permeability to propidium iodide (PI) was nearly abolished in strain CaTK1 (TRK1/trk1), suggesting that Hst 5-induced influx of PI is via Trk1p. To explore the functional role of Trk1p in the mechanism of other antifungal peptides, we evaluated candidacidal activity and PI uptake in wild-type strain CaTK2 (TRK1/TRK1) and strain CaTK1 following treatment with lactoferricin 11 (LFcn 11), bactenecin 16 (BN 16), and virion-associated protein VPR 12. Strain CaTK1 was resistant to killing with these peptides (VPR 12 > LFcn 11 > BN 16), showing the requirement of Trk1p for fungicidal activity. In contrast, human neutrophil defensin 1 (HNP-1), human β-defensin 2 (hBD-2), and hBD-3 effects on viability of and membrane permeability to PI were not different between mutant and wild-type strains, clearly showing that their candidacidal mechanism does not involve Trk1p as a functional effector. To test whether defensins require binding to Candida surface Ssa1/2 proteins for their activity, we measured the killing effectiveness in SSA1/2 mutant strains. Both hBD-2 and hBD-3, but not HNP-1, exhibited reduced killing of ssa1Δ and ssa2Δ strains compared to the wild type, showing that Ssa1 and Ssa2 proteins are required for their fungicidal activity. These results demonstrate that (i) Trk1p mediates candidacidal activities of cysteine-free peptides, but not of defensins, and (ii) hBD-2 and hBD-3, but not HNP-1, require Ssa1/2p for antifungal activity.
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Borsotto, M., A. Djillani, C. Devader, C. Heurteaux, and J. Mazella. "The Mini-Spadin, an efficient alternate to Spadin in the depression treatment." European Psychiatry 33, S1 (March 2016): S407. http://dx.doi.org/10.1016/j.eurpsy.2016.01.1470.
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ObjectivesWe previously discovered spadin as a new antidepressant drug concept. Spadin exerts its antidepressant actions on the TREK-1 potassium channel, a new antidepressant (AD) target. We have shown that spadin acts more rapidly in comparison to other ADs. We have pointed out that spadin induced neurogenesis after only 4-day treatments. We have demonstrated that spadin did not display side effects at the cardiac level and on TREK-1 controlled functions such as stroke, epilepsy or pain.ObjectivesWith the final goal to make spadin a drug for human clinic, our objective was to find analogs of spadin demonstrating a better affinity or a better in vivo stability or both.MethodsSeveral analogs of spadin were synthesized. Their ability to block the TREK-1 channel activity were first tested by electrophysiology on HEK293 cells stably transfected with TREK-1 channels. AD effects were measured by using the forced swim test and the novelty suppressed feeding test. Neurogenesis was investigated by measuring the expression level of the synaptic protein PSD-95 in in vitro cultured neurons.ResultsOur data allow us to identify a shortened spadin, called mini-spadin, that displayed the same AD properties as spadin and a 400 fold increase in the TREK-1 affinity. Mini-spadin increased the synaptogenesis marker PSD95 levels after only 24 hours of treatment, suggesting that like spadin, mini-spadin was able to induce neurogenesis and synaptogenesis.ConclusionsEven if further experiments are required, the mini-spadin appears to be more efficient than spadin offering a very promising alternate to spadin as human drug.Disclosure of interestThe authors have not supplied their declaration of competing interest.
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Silva, Denis de Castro, Ednelza da Silva Graça Amoras, Tuane Carolina Ferreira Moura, Felipe Teixeira Lopes, Samara Tatielle Monteiro Gomes, Carlos A. da Costa, Maísa Silva Sousa, Ricardo Ishak, Antonio Carlos Rosário Vallinoto, and Maria Alice Freitas Queiroz. "TREX1 531C>T Polymorphism is Associated with High Proviral Load Levels in HTLV-1-Infected Persons." Viruses 12, no. 1 (December 19, 2019): 7. http://dx.doi.org/10.3390/v12010007.
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Human T-lymphotropic virus type 1 (HTLV-1) deregulates the immune system and cell cycle, resulting in loss of immune tolerance and disease, including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Three prime repair exonuclease 1 (TREX1) maintains innate immune tolerance of the host and host-cell permissiveness to retroviral infections. TREX1 polymorphisms may influence the course of infection and autoimmune manifestations. The influence of TREX1 531C/T polymorphism was investigated in HTLV-1 infection and development of symptoms among 151 persons infected with HTLV-1 (32 HAM/TSP, 19 rheumatologic manifestations, two dermatitis, five more than one diagnosis, two probable HAM/TSP, and 91 asymptomatic individuals) and 100 uninfected persons in the control group. Polymorphism genotyping and proviral load quantification were performed by real-time polymerase chain reaction (PCR) and antinuclear antibodies (ANAs) were screened by an indirect immunofluorescence assay. No statistically significant difference was found in polymorphism genotype and allele frequencies between the infected and control groups. HAM/TSP patients showed higher frequency of TT genotype than asymptomatic persons (p = 0.0339). Proviral load was significantly higher among individuals with CT/TT genotypes and CC genotype carriers had lower proviral load and higher levels of proinflammatory cytokines. ANAs were present only in the HAM/TSP group. TREX1 531C>T polymorphism seems to be associated with TREX-1 regulation and HTLV-1 infection.
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Heyman, Nathanael S., Chad L. Cowles, Scott D. Barnett, Yi-Ying Wu, Charles Cullison, Cherie A. Singer, Normand Leblanc, and Iain L. O. Buxton. "TREK-1 currents in smooth muscle cells from pregnant human myometrium." American Journal of Physiology-Cell Physiology 305, no. 6 (September 15, 2013): C632—C642. http://dx.doi.org/10.1152/ajpcell.00324.2012.
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The mechanisms governing maintenance of quiescence during pregnancy remain largely unknown. The current study characterizes a stretch-activated, tetraethylammonium-insensitive K+ current in smooth muscle cells isolated from pregnant human myometrium. This study hypothesizes that these K+ currents can be attributed to TREK-1 and that upregulation of this channel during pregnancy assists with the maintenance of a negative cell membrane potential, conceivably contributing to uterine quiescence until full term. The results of this study demonstrate that, in pregnant human myometrial cells, outward currents at 80 mV increased from 4.8 ± 1.5 to 19.4 ± 7.5 pA/pF and from 3.0 ± 0.8 to 11.8 ± 2.7 pA/pF with application of arachidonic acid (AA) and NaHCO3, respectively, causing intracellular acidification. Similarly, outward currents were inhibited following application of 10 μM fluphenazine by 51.2 ± 9.8% after activation by AA and by 73.9 ± 4.2% after activation by NaHCO3. In human embryonic kidney (HEK-293) cells stably expressing TREK-1, outward currents at 80 mV increased from 91.0 ± 23.8 to 247.5 ± 73.3 pA/pF and from 34.8 ± 8.9 to 218.6 ± 45.0 pA/pF with application of AA and NaHCO3, respectively. Correspondingly, outward currents were inhibited 89.5 ± 2.3% by 10 μM fluphenazine following activation by AA and by 91.6 ± 3.4% following activation by NaHCO3. Moreover, currents in human myometrial cells were activated by stretch and were reduced by transfection with small interfering RNA or extracellular acidification. Understanding gestational regulation of expression and gating of TREK-1 channels could be important in determining appropriate maintenance of uterine quiescence during pregnancy.
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Kavanagh, David, Dirk Spitzer, Parul Kothari, Aisha Shaikh, M. Kathryn Liszewski, Anna Richards, and John P. Atkinson. "New roles for the major human 3′-5′ exonuclease TREX1 in human disease." Cell Cycle 7, no. 12 (June 15, 2008): 1718–25. http://dx.doi.org/10.4161/cc.7.12.6162.
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Toyoda, N., A. M. Zavacki, A. L. Maia, J. W. Harney, and P. R. Larsen. "A novel retinoid X receptor-independent thyroid hormone response element is present in the human type 1 deiodinase gene." Molecular and Cellular Biology 15, no. 9 (September 1995): 5100–5112. http://dx.doi.org/10.1128/mcb.15.9.5100.
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We identified two thyroid hormone response elements (TREs) in the 2.5-kb, 5'-flanking region of the human gene encoding type 1 iodothyronine deiodinase (hdio1), an enzyme which catalyses the activation of thyroxine to 3,5,3'-triiodothyronine (T3). Both TREs contribute equally to T3 induction of the homologous promoter in transient expression assays. The proximal TRE (TRE1), which is located at bp -100, has an unusual structure, a direct repeat of the octamer YYRGGTCA hexamer that is spaced by 10 bp. The pyrimidines in the -2 position relative to the core hexamer are both essential to function. In vitro binding studies of TRE1 showed no heterodimer formation with retinoid X receptor (RXR) beta or JEG nuclear extracts (containing RXR alpha) and bacterially expressed chicken T3 receptor alpha 1 (TR alpha) can occupy both half-sites although the 3' half-site is dominant. T3 causes dissociation of TR alpha from the 5' half-site but increases binding to the 3' half-site. Binding of a second TR to TRE1 is minimally cooperative; however, no cooperativity was noted for a functional mutant in which the half-sites are separated by 15 bp, implying that TRs bind as independent monomers. Nonetheless, T3 still causes TR dissociation from the DR+15, indicating that dissociation occurs independently of TR-TR contact and that rebinding of a T3-TR complex to the 3' half-site occurs because of its slightly higher affinity. A distal TRE (TRE2) is found at bp -700 and is a direct repeat of a PuGGTCA hexamer spaced by 4 bp. It has typical TR homodimer and TR-RXR heterodimer binding properties. The TRE1 of hdio1 is the first example of a naturally occurring TRE consisting of two relatively independent octamer sequences which do not require the RXR family of proteins for function.
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Hughes, Steven, Stuart McBain, Jon Dobson, and Alicia J. El Haj. "Selective activation of mechanosensitive ion channels using magnetic particles." Journal of The Royal Society Interface 5, no. 25 (December 11, 2007): 855–63. http://dx.doi.org/10.1098/rsif.2007.1274.
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This study reports the preliminary development of a novel magnetic particle-based technique that permits the application of highly localized mechanical forces directly to specific regions of an ion-channel structure. We demonstrate that this approach can be used to directly and selectively activate a mechanosensitive ion channel of interest, namely TREK-1. It is shown that manipulation of particles targeted against the extended extracellular loop region of TREK-1 leads to changes in whole-cell currents consistent with changes in TREK-1 activity. Responses were absent when particles were coated with RGD (Arg–Gly–Asp) peptide or when magnetic fields were applied in the absence of magnetic particles. It is concluded that changes in whole-cell current are the result of direct force application to the extracellular loop region of TREK-1 and thus these results implicate this region of the channel structure in mechano-gating. It is hypothesized that the extended loop region of TREK-1 may act as a tension spring that acts to regulate sensitivity to mechanical forces, in a nature similar to that described for MscL. The development of a technique that permits the direct manipulation of mechanosensitive ion channels in real time without the need for pharmacological drugs has huge potential benefits not only for basic biological research of ion-channel gating mechanisms, but also potentially as a tool for the treatment of human diseases caused by ion-channel dysfunction.
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Cudeville, Corinne, Françoise Mondon, Brigitte Robert, Régis Rebourcet, Thérèse-Marie Mignot, Claudine Benassayag, and Françoise Ferré. "Evidence for Progesterone Receptors in the Human Fetoplacental Vascular Tree1." Biology of Reproduction 62, no. 3 (March 1, 2000): 759–65. http://dx.doi.org/10.1095/biolreprod62.3.759.
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Ohara, A., Y. Saeki, M. Nishikawa, Y. Yamamoto, and G. Yamamoto. "Single-channel Recordings of TREK-1 K+ Channels in Periodontal Ligament Fibroblasts." Journal of Dental Research 85, no. 7 (July 2006): 664–69. http://dx.doi.org/10.1177/154405910608500716.
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The periodontal ligament (PDL) works as a suspensory ligament when external mechanical stress is placed on the teeth. PDL fibroblasts, the principal cells in the PDL, are responsible for many PDL functions. We hypothesized that mechanosensitive ion channels are present in human PDL fibroblasts, which are capable of responding to mechanical stress during normal function of the tissue. Using patch-clamp techniques, we detected mechanosensitive TREK-1 K+ channels (a member of the two-pore-domain K+ channel family), whose single-channel conductance was 104 pS in symmetrical K+-rich solutions. The open probability of the channel was low in the quiescent state, but it was strongly increased by the induction of membrane stretch. Arachidonic acid also enhanced the channel activity. RT-PCR and immunocytochemical observations showed the expression of TREK-1 K+ channels in PDL fibroblasts. The results suggest that the activation of TREK-1 K+ channels by masticatory stress contributes to the hyperpolarization of PDL fibroblasts.
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Kolstad, Arne, and Kristian Hannestad. "A supertypic HLA-DP specificity defined by two human-human hybridoma antibodies (TrB50; TrE11)." Human Immunology 25, no. 4 (August 1989): 247–56. http://dx.doi.org/10.1016/0198-8859(89)90087-6.
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Cappelli, Giulia, Daniela Giovannini, Annalisa Basso, Annalucia Serafino, Federica Andreola, Vittorio Colizzi, and Francesca Mariani. "A New CpG ODN Induces a Fine-Tuning of Innate Response Resulting in Mycobacterium tuberculosis Containment." Journal of Biomedical Research & Environmental Sciences 3, no. 7 (July 2022): 802–18. http://dx.doi.org/10.37871/jbres1517.
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Synthetic oligodeoxynucleotides containing bacterial CpG motifs trigger an immunomodulatory response that correlates with both the CpG hhhexamers and their flanking regions. In this study, four new phosphodiester backbone CpG ODNs were studied in the contest of the innate immune response to Mycobacterium tuberculosis (MTB) infection. Two out of the four CpG ODNs (CpG2 and CpG3) displayed significant and opposite immunomodulatory effects: CpG2 enhanced MTB containment by human Monocyte-Derived-Macrophages (MDM), while CpG3 promoted an increased pathogen growth, higher ROS and Labile Iron Pool (LIP) levels. Accordingly, for iron homeostasis genes transcription, CpG2 and CpG3 induced, respectively, an iron retention and iron release phenotype. Moreover, CpG2 induced NLRC4 and TRAF6 gene expression and repressed IKK alpha and TREM1 while CpG3 induced PPBP and IL-36 RN and repressed TRAF6, IL-1B, IL-1R2 and NF-kB2. After MTB infection, CpG2 increased the release of soluble TREM1 protein among many others as compared with fewer innate response-associated proteins induced by CpG3. We suggest that CpG2 helps the containment of MTB infection, by inducing an early tight balance of MDM activation players, including LIP, chemokines, ROS and TREM1 receptors. Oppositely, CpG3 induces in MDM an excessive and unregulated inflammatory response unable to contain MTB infection.
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Magra, Merzesh, Steven Hughes, Alicia J. El Haj, and Nicola Maffulli. "VOCCs and TREK-1 ion channel expression in human tenocytes." American Journal of Physiology-Cell Physiology 292, no. 3 (March 2007): C1053—C1060. http://dx.doi.org/10.1152/ajpcell.00053.2006.
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Mechanosensitive and voltage-gated ion channels are known to perform important roles in mechanotransduction in a number of connective tissues, including bone and muscle. It is hypothesized that voltage-gated and mechanosensitive ion channels also may play a key role in some or all initial responses of human tenocytes to mechanical stimulation. However, to date there has been no direct investigation of ion channel expression by human tenocytes. Human tenocytes were cultured from patellar tendon samples harvested from five patients undergoing routine total knee replacement surgery (mean age: 66 yr; range: 63–73 yr). RT-PCR, Western blotting, and whole cell electrophysiological studies were performed to investigate the expression of different classes of ion channels within tenocytes. Human tenocytes expressed mRNA and protein encoding voltage-operated calcium channel (VOCC) subunits (Ca α1A, Ca α1C, Ca α1D, Ca α2δ1) and the mechanosensitive tandem pore domain potassium channel (2PK+) TREK-1. They exhibit whole cell currents consistent with the functional expression of these channels. In addition, other ionic currents were detected within tenocytes consistent with the expression of a diverse array of other ion channels. VOCCs and TREK channels have been implicated in mechanotransduction signaling pathways in numerous connective tissue cell types. These mechanisms may be present in human tenocytes. In addition, human tenocytes may express other channel currents. Ion channels may represent potential targets for the pharmacological management of chronic tendinopathies.
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Magalhaes, Diogo, Laurent Peyrin-Biroulet, Maria Manuela Estevinho, Silvio Danese, and Fernando Magro. "Pursuing neutrophils: systematic scoping review on blood-based biomarkers as predictors of treatment outcomes in inflammatory bowel disease." Therapeutic Advances in Gastroenterology 16 (January 2023): 175628482311559. http://dx.doi.org/10.1177/17562848231155987.
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Background: Long-term management of inflammatory bowel diseases (IBD) is challenging and the identification of reliable predictors for treatment outcomes is an unmet need. Neutrophil-related biomarkers have been mainly studied in the feces, but blood analyses have inherent advantages. Objective: To review the recent learnings on the ability of blood-based neutrophil-expressed biomarkers to predict treatment outcomes in IBD. Design: Systematic scoping review. Data sources and methods: We performed a literature search in Pubmed, EMBASE, SCOPUS, Web of Science, ScienceDirect, and Cochrane Central Register of Controlled Trials from inception until May 2022 according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. All human studies associating blood-based neutrophil-related compounds with the prediction of disease progression, complication onset, or treatment outcomes were included. Results: From 1032 retrieved entries, 34 studies were selected, 32 published in 2013 or later. In all, 17 biomarkers from granules, cytoplasm, plasmatic membrane, and plasma were explored. In total, 1850 Crohn’s disease (CD) and 1122 ulcerative colitis non-duplicated patients were included. The most mentioned biomarkers were nCD64, serum calprotectin (SC), oncostatin M (OSM), neutrophil elastase-generated calprotectin fragment (CPa9-HNE), and triggering receptor expressed on myeloid cells 1 (TREM1). Six biomarkers showed promising results: OSM, SC, eNAMPT, nCD64, TREM1, and CPa9-HNE. Variable positive signals were found for human neutrophil peptide 1-3, LL-37, S100A12, and neutrophil gelatinase–associated lipocalin. No predictive ability was found for the remaining markers. Sharing a neutrophil compartment did not indicate similar behavior. Conclusion: Advances in the last decade began to unveil the untapped potential of the readily accessible blood neutrophil-expressed biomarkers, especially nCD64, TREM1, and CPa9-HNE. Current evidence suggests that future research should focus on well-defined subpopulations instead of a one-size-fits-all biomarker. Registration: https://osf.io/kes9a .
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ANNAS, GEORGE J. "Human Rights and American Bioethics: Resistance Is Futile." Cambridge Quarterly of Healthcare Ethics 19, no. 1 (December 22, 2009): 133–41. http://dx.doi.org/10.1017/s0963180109990338.
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The Borg are always confident that humans will be assimilated into their collective hive and therefore that, as they say, “resistance is futile.” In Star Trek, of course, the humans always successfully resist. Elizabeth Fenton and John Arras, like the Borg, resist the idea that humans are uniquely special as well as the utility of the human rights framework for global bioethics. I believe their resistance to human rights is futile, and I explain why in this essay. Let me begin with their subtitle, because we do seem to agree that popular culture is a powerful aid to understanding human actions and motivations.
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Harinath, S., and S. K. Sikdar. "Inhibition of human TREK-1 channels by caffeine and theophylline." Epilepsy Research 64, no. 3 (May 2005): 127–35. http://dx.doi.org/10.1016/j.eplepsyres.2005.03.002.
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Bower, Bruce. "Asian trek: Fossil puts ancient humans in far east." Science News 171, no. 14 (April 7, 2007): 211. http://dx.doi.org/10.1002/scin.2007.5591711402.
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Deguchi, Akari, Rubii Kondo, Yoshiaki Suzuki, and Hisao Yamamura. "Functional expression of TREK-1 channels in human hepatic stellate cells." Proceedings for Annual Meeting of The Japanese Pharmacological Society 94 (2021): 3—O—D2–4. http://dx.doi.org/10.1254/jpssuppl.94.0_3-o-d2-4.
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Magloire, H., F. Lesage, M. L. Couble, M. Lazdunski, and F. Bleicher. "Expression and Localization of TREK-1 K+Channels in Human Odontoblasts." Journal of Dental Research 82, no. 7 (July 2003): 542–45. http://dx.doi.org/10.1177/154405910308200711.
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