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Ben Shimon M, Lenz M, Ikenberg B, Becker D, Shavit Stein E, Chapman J, Tanne D, Pick CG, Blatt I, Neufeld M, Vlachos A, Maggio N. Thrombin regulation of synaptic transmission and plasticity: implications for health and disease. Front Cell Neurosci 2015; 9:151. [PMID: 25954157 PMCID: PMC4404867 DOI: 10.3389/fncel.2015.00151] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/01/2015] [Indexed: 11/13/2022] Open
Abstract
Thrombin, a serine protease involved in the blood coagulation cascade has been shown to affect neural function following blood-brain barrier breakdown. However, several lines of evidence exist that thrombin is also expressed in the brain under physiological conditions, suggesting an involvement of thrombin in the regulation of normal brain functions. Here, we review ours’ as well as others’ recent work on the role of thrombin in synaptic transmission and plasticity through direct or indirect activation of Protease-Activated Receptor-1 (PAR1). These studies propose a novel role of thrombin in synaptic plasticity, both in physiology as well as in neurological diseases associated with increased brain thrombin/PAR1 levels.
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Review |
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Shimon MB, Goldshleger R, Karlish SJ. Specific Cu2+-catalyzed oxidative cleavage of Na,K-ATPase at the extracellular surface. J Biol Chem 1998; 273:34190-5. [PMID: 9852080 DOI: 10.1074/jbc.273.51.34190] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This paper describes specific Cu2+-catalyzed oxidative cleavage of alpha and beta subunits of Na,K-ATPase at the extracellular surface. Incubation of right side-out renal microsomal vesicles with Cu2+ ions, ascorbate, and H2O2 produces two major cleavages of the alpha subunit within the extracellular loop between trans-membrane segments M7 and M8 and L7/8. Minor cleavages are also detected in loops L9/10 and L5/6. In the beta subunit two cleavages are detected, one before the first S-S bridge and the other between the second and third S-S bridges. Na,K-ATPase and Rb+ occlusion are inactivated after incubation with Cu2+/ascorbate/H2O2. These observations are suggestive of a site-specific mechanism involving cleavage of peptide bonds close to a bound Cu2+ ion. This mechanism allows several inferences on subunit interactions and spatial organization. The two cleavage sites in L7/8 of the alpha subunit and two cleavage sites of the beta subunit identify interacting segments of the subunits. L7/8 is also close to L9/10 and to cation occlusion sites. Comparison of the locations of Cu2+-catalyzed cleavages with Fe2+-catalyzed cleavages (Goldshleger, R., and Karlish, S. J. D. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 9596-9601) suggests division of the membrane sector into two domains comprising M1-M6 and M7-M10/Mbeta, respectively.
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Shapira S, Shimon MB, Hay-Levi M, Shenberg G, Choshen G, Bannon L, Tepper M, Kazanov D, Seni J, Lev-Ari S, Peer M, Boubas D, Stebbing J, Tsiodras S, Arber N. A novel platform for attenuating immune hyperactivity using EXO-CD24 in Covid-19 and beyond. EMBO Mol Med 2022; 14:e15997. [PMID: 35776000 PMCID: PMC9349550 DOI: 10.15252/emmm.202215997] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 11/09/2022] Open
Abstract
A small but significant proportion of Covid19 patients develop life-threatening cytokine storm. We have developed a new anti-inflammatory drug, EXO-CD24, a combination of an immune checkpoint (CD24) and a delivery platform (exosomes). CD24 inhibits the NF-kB pathway and the production of cytokines/chemokines. EXO-CD24 discriminates Damage- from Pathogen-Associated Molecular Patterns (DAMPs and PAMPs) therefore does not interfere with viral clearance. EXO-CD24 was produced and purified from CD24-expressing 293-TREx™ cells. Exosomes displaying murine CD24 (mCD24) were also created. EXO-CD24/mCD24 were characterized and examined, for safety and efficacy, in vitro and in vivo. In a phase Ib/IIa study, 35 patients with moderate-high severity COVID-19 were recruited and given escalating doses, 108 -1010 , of EXO-CD24 by inhalation, QD, for five days. No adverse events related to the drug were observed up to 443-575 days. EXO-CD24 effectively reduced inflammatory markers and cytokine/chemokine, though randomized studies are required. EXO CD24 may be a treatment strategy to suppress the hyper-inflammatory response in the lungs of Covid-19 patients and further serve as a therapeutic platform for other pulmonary and systemic diseases characterized by cytokine storm.
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Shimon M, Egozi Y, Kloog Y, Sokolovsky M, Cohen S. Kinetics of choline uptake into isolated rat forebrain microvessels: evidence of endocrine modulation. J Neurochem 1988; 50:1719-24. [PMID: 3373211 DOI: 10.1111/j.1471-4159.1988.tb02469.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The active uptake of [methyl-3H]choline into isolated rat brain microvessel suspension was studied as a likely guide to the transport of choline across the blood-brain barrier. The method consisted primarily of incubation of the suspension with a fixed concentration of labeled choline in the presence of increasing concentrations of unlabeled choline or any other inhibitor (I) of active uptake, defined as the difference in uptake at 37 degrees and 0 degrees C. From the linear regression of (1/V) against [I], the following values of Vmax (nmol g-1 min-1) and Km (microM) were obtained for choline: 2-month-old males, 10.6 +/- 3.8 and 6.1 +/- 0.9; 3-month old random females, 28.4 +/- 5.9 and 12.6 +/- 4.0; females at metaestrus, 17.8 +/- 10.3 and 8.3 +/- 5.0; at diestrus, 31.1 +/- 9.3 and 13.0 +/- 2.6; at proestrus, 54.9 +/- 2.2 and 14.0 +/- 1.5; at estrus, 19.2 +/- 2.2 and 2.6 +/- 1.7. The differences between males and random females (p less than 0.018) and between females at proestrus and estrus (p less than 0.005) are significant. It is suggested that these inter- and intrasex variations in choline uptake reflect a dynamic adjustment of supply in accordance with brain demand for choline at the time of assay. Hemicholinium-3 was an effective inhibitor of choline uptake, Ki = 14.0 +/- 8.5 microM; dimethylaminoethanol was much less effective; and imipramine had no measurable effect.
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Comparative Study |
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Bushi D, Ben Shimon M, Shavit Stein E, Chapman J, Maggio N, Tanne D. Increased thrombin activity following reperfusion after ischemic stroke alters synaptic transmission in the hippocampus. J Neurochem 2015; 135:1140-8. [PMID: 26390857 DOI: 10.1111/jnc.13372] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 11/24/2022]
Abstract
Thrombin, a key player in thrombogenesis, affects cells in the brain through activation of its receptors. Low levels of thrombin activity are protective while high levels are toxic. We sought to quantify thrombin activity levels and their spatial distribution in brains of mice following reperfusion after ischemic stroke focusing on infarct, peri-infarct and contralateral areas. In order to find out the contribution of brain-derived thrombin, mRNA levels of both prothrombin and factor X were determined. Furthermore, we assessed the effect of thrombin levels that were measured in the ischemic brain on synaptic transmission. We found that in the brains of mice following transient middle cerebral artery occlusion, thrombin activity is elevated throughout the ischemic hemisphere, including in peri-infarct areas (90 ± 33 and 60 ± 18 mU/mL, in the infarct and peri-infarct areas, respectively, compared to 11 ± 3 and 12 ± 5 mU/mL, in the corresponding contralateral areas; mean ± SE; p < 0.05). Brain mRNA levels of prothrombin and, in particular, factor X are up-regulated in the ischemic core. Hippocampal slices treated with thrombin concentrations as found in the ischemic hemisphere show altered synaptic responses. We conclude that high thrombin activity following reperfusion after ischemic stroke may cause synaptic dysfunction. Following transient middle cerebral artery occlusion in mice, thrombin activity is elevated throughout the ischemic hemisphere, including in peri-infarct areas. Brain mRNA levels of prothrombin and factor X are up-regulated in the ischemic core. Thrombin is known to affect synaptic function in a concentration dependent manner and hippocampal slices treated with the concentrations found in the ischemic hemisphere show altered synaptic responses. We conclude that in ischemic stroke, the high brain thrombin activity found after reperfusion may cause synaptic dysfunction.
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Research Support, Non-U.S. Gov't |
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Goldshleger R, Patchornik G, Shimon MB, Tal DM, Post RL, Karlish SJ. Structural organization and energy transduction mechanism of Na+,K+-ATPase studied with transition metal-catalyzed oxidative cleavage. J Bioenerg Biomembr 2001; 33:387-99. [PMID: 11762914 DOI: 10.1023/a:1010615422932] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This chapter describes contributions of transition metal-catalyzed oxidative cleavage of Na+,K+-ATPase to our understanding of structure-function relations. In the presence of ascorbate/H2O2, specific cleavages are catalyzed by the bound metal and because more than one peptide bond close to the metal can be cleaved, this technique reveals proximity of the different cleavage positions within the native structure. Specific cleavages are catalyzed by Fe2+ bound at the cytoplasmic surface or by complexes of ATP-Fe2+, which directs the Fe2+ to the normal ATP-Mg2+ site. Fe2+- and ATP-Fe2+-catalyzed cleavages reveal large conformation-dependent changes in interactions between cytoplasmic domains, involving conserved cytoplasmic sequences, and a change of ligation of Mg2+ ions between E1P and E2P, which may be crucial in facilitating hydrolysis of E2P. The pattern of domain interactions in E1 and E2 conformations, and role of Mg2+ ions, may be common to all P-type pumps. Specific cleavages can also be catalyzed by Cu2+ ions, bound at the extracellular surfaces, or a hydrophobic Cu2+-diphenyl phenanthroline (DPP) complex, which directs the Cu2+ to the membrane-water interface. Cu2+ or Cu2+-DPP-catalyzed cleavages are providing information on alpha/beta subunit interactions and spatial organization of transmembrane segments. Transition metal-catalyzed cleavage could be widely used to investigate other P-type pumps and membrane proteins and, especially, ATP binding proteins.
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Review |
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Gera O, Shavit-Stein E, Bushi D, Harnof S, Shimon MB, Weiss R, Golderman V, Dori A, Maggio N, Finegold K, Chapman J. Thrombin and protein C pathway in peripheral nerve Schwann cells. Neuroscience 2016; 339:587-598. [PMID: 27771530 DOI: 10.1016/j.neuroscience.2016.10.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/22/2016] [Accepted: 10/11/2016] [Indexed: 11/24/2022]
Abstract
Thrombin and activated protein C (aPC) bound to the endothelial protein C receptor (EPCR) both activate protease-activated receptor 1 (PAR1) generating either harmful or protective signaling respectively. In the present study we examined the localization of PAR-1 and EPCR and thrombin activity in Schwann glial cells of normal and crushed peripheral nerve and in Schwannoma cell lines. In the sciatic crush model nerves were excised 1h, 1, 4, and 7days after the injury. Schwannoma cell lines produced high levels of prothrombin which is converted to active thrombin and expressed both EPCR and PAR-1 which co-localized. In the injured sciatic nerve thrombin levels were elevated as early as 1h after injury, reached their peak 1day after injury which was significantly higher (24.4±4.1mU/ml) compared to contralateral uninjured nerves (2.6±7mU/ml, t-test p<0.001) and declined linearly reaching baseline levels by day 7. EPCR was found to be located at the microvilli of Schwann cells at the node of Ranvier and in cytoplasm surrounding the nucleus. Four days after sciatic injury, EPCR levels increased significantly (57,785±16602AU versus 4790±1294AU in the contralateral uninjured nerves, p<0.001 by t-test) mainly distal to the site of injury, where axon degeneration is followed by proliferation of Schwann cells which are diffusely stained for EPCR. EPCR seems to be located to cytoplasmic component of Schwann cells and not to compact myelin component, and is highly increased following injury.
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Journal Article |
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Ben Shimon M, Zeimer T, Shavit Stein E, Artan-Furman A, Harnof S, Chapman J, Eisenkraft A, Pick CG, Maggio N. Recovery from trauma induced amnesia correlates with normalization of thrombin activity in the mouse hippocampus. PLoS One 2017; 12:e0188524. [PMID: 29182653 PMCID: PMC5705129 DOI: 10.1371/journal.pone.0188524] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 11/08/2017] [Indexed: 12/23/2022] Open
Abstract
Transient amnesia is a common consequence of minimal traumatic brain injury (mTBI). However, while recent findings have addressed the mechanisms involved in its onset, the processes contributing to its recovery have not yet been addressed. Recently, we have found that thrombin is detected at high concentrations in the brain of mice after exposure to mTBI and that in such settings amnesia is rescued by either inhibiting thrombin activity or by blockade of PAR1. Here, we report that mice spontaneously recover from amnesia after two weeks from mTBI exposure. At this time point, long term potentiation was equally evoked in injured vs. control animals with thrombin concentration in the brain being normalized at this stage. These findings, which refer to the specific aspect of memory retrieval upon mTBI, together with our previous work, hint to a strong correlation between cognitive defects in the context of mTBI and thrombin concentrations in the brain. This may suggest that a possible scavenging of thrombin in the brain at early phases following mTBI may improve memory function.
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Journal Article |
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Ade PAR, Akiba Y, Anthony AE, Arnold K, Atlas M, Barron D, Boettger D, Borrill J, Chapman S, Chinone Y, Dobbs M, Elleflot T, Errard J, Fabbian G, Feng C, Flanigan D, Gilbert A, Grainger W, Halverson NW, Hasegawa M, Hattori K, Hazumi M, Holzapfel WL, Hori Y, Howard J, Hyland P, Inoue Y, Jaehnig GC, Jaffe A, Keating B, Kermish Z, Keskitalo R, Kisner T, Le Jeune M, Lee AT, Linder E, Leitch EM, Lungu M, Matsuda F, Matsumura T, Meng X, Miller NJ, Morii H, Moyerman S, Myers MJ, Navaroli M, Nishino H, Paar H, Peloton J, Quealy E, Rebeiz G, Reichardt CL, Richards PL, Ross C, Schanning I, Schenck DE, Sherwin B, Shimizu A, Shimmin C, Shimon M, Siritanasak P, Smecher G, Spieler H, Stebor N, Steinbach B, Stompor R, Suzuki A, Takakura S, Tomaru T, Wilson B, Yadav A, Zahn O. Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment. PHYSICAL REVIEW LETTERS 2014; 113:021301. [PMID: 25062161 DOI: 10.1103/physrevlett.113.021301] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Indexed: 06/03/2023]
Abstract
Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.
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Ben Shimon M, Shavit-Stein E, Altman K, Pick CG, Maggio N. Thrombin as Key Mediator of Seizure Development Following Traumatic Brain Injury. Front Pharmacol 2020; 10:1532. [PMID: 32009953 PMCID: PMC6971217 DOI: 10.3389/fphar.2019.01532] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 11/27/2019] [Indexed: 12/16/2022] Open
Abstract
Traumatic brain injury (TBI) commonly leads to development of seizures, accounting for approximately 20% of newly diagnosed epilepsy. Despite the high clinical significance, the mechanisms underlying the development of posttraumatic seizures (PTS) remain unclear, compromising appropriate management of these patients. Accumulating evidence suggest that thrombin, the main serine protease of the coagulation cascade, is involved in PTS genesis by mediating inflammation and hyperexcitability following blood brain barrier breakdown. In order to further understand the role of thrombin in PTS, we generated a combined mild TBI (mTBI) and status epilepticus mice model, by injecting pilocarpine to mice previously submitted to head injury. Interestingly, mTBI was able to reduce seizure onset in the pilocarpine animal model as well as increase the death rate in the treated animals. In turn, pilocarpine worsened spatial orientation of mTBI treated mice. Finally, thrombin activity as well as the expression of IL1-β and TNF-α was significantly increased in the mTBI-pilocarpine treated animals. In conclusion, these observations indicate a synergism between thrombin and mTBI in lowering seizure in the pilocarpine model and possibly aggravating inflammation. We believe that these results will improve the understanding of PTS pathophysiology and contribute to the development of more targeted therapies in the future.
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Journal Article |
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Shimon M, Egozi Y, Kloog Y, Sokolovsky M, Cohen S. Vascular cholinesterases and choline uptake in isolated rat forebrain microvessels: a possible link. J Neurochem 1989; 53:561-5. [PMID: 2746236 DOI: 10.1111/j.1471-4159.1989.tb07370.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The two parameters of the active [methyl-3H]choline uptake into isolated rat forebrain microvessels, Km and Vmax, were determined for 1-, 3-, 10-, and 24-month-old Charles River male rats and compared with the activities of the enzymes choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) in these microvessels over the same time course. The value of Km remained constant over the entire period, but that of Vmax increased from 8.5 +/- 1.0 to 80.6 +/- 16.4 nmol g-1 (mean +/- SEM) over the first 3 months of life. Over the same period, the increase in ChAT activity, from an initial value of 7.1 +/- 1.6 to 10.2 +/- 0.3 nmol g-1 min-1, was not proportional to that of choline uptake. Levels of BuChE activity (0.9-1.3 mumol g-1 min-1) were almost unchanged throughout the entire 24-month period, but those of AChE showed a steady and significant increase from 1 to 24 months, remaining relatively high at senescence (4.7 mumol g-1 min-1), when choline uptake had decreased to one-third of its optimal value. Selective inhibition of AChE with 1,5-bis(4-allyldimethylammonium-phenyl)pentan-3-one dibromide (0.5 microM) in unruptured capillaries from 3-month-old rats resulted in a decrease in Vmax of choline uptake from approximately 81 to 59 nmol g-1 min-1 or with 9-amino-1,2,3,4-tetrahydroacridine (10 microM) in capillaries from 2-month-old rats from approximately 30 to 15 nmol g-1 min-1. Selective inhibition of BuChE with tetraisopropyl pyrophosphoramide (100 microM) resulted in an increase in Vmax from approximately 81 to 96 nmol g-1 min-1. It is possible that the two vascular enzyme systems are coupled to a hypothetical endothelial choline transporter, but with an action opposite to each other.
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Ade PAR, Akiba Y, Anthony AE, Arnold K, Atlas M, Barron D, Boettger D, Borrill J, Borys C, Chapman S, Chinone Y, Dobbs M, Elleflot T, Errard J, Fabbian G, Feng C, Flanigan D, Gilbert A, Grainger W, Halverson NW, Hasegawa M, Hattori K, Hazumi M, Holzapfel WL, Hori Y, Howard J, Hyland P, Inoue Y, Jaehnig GC, Jaffe A, Keating B, Kermish Z, Keskitalo R, Kisner T, Le Jeune M, Lee AT, Leitch EM, Linder E, Lungu M, Matsuda F, Matsumura T, Meng X, Miller NJ, Morii H, Moyerman S, Myers MJ, Navaroli M, Nishino H, Paar H, Peloton J, Poletti D, Quealy E, Rebeiz G, Reichardt CL, Richards PL, Ross C, Rotermund K, Schanning I, Schenck DE, Sherwin BD, Shimizu A, Shimmin C, Shimon M, Siritanasak P, Smecher G, Spieler H, Stebor N, Steinbach B, Stompor R, Suzuki A, Takakura S, Tikhomirov A, Tomaru T, Wilson B, Yadav A, Zahn O. Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background. PHYSICAL REVIEW LETTERS 2014; 112:131302. [PMID: 24745402 DOI: 10.1103/physrevlett.112.131302] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Indexed: 06/03/2023]
Abstract
We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.
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Shavit-Stein E, Artan-Furman A, Feingold E, Ben Shimon M, Itzekson-Hayosh Z, Chapman J, Vlachos A, Maggio N. Protease Activated Receptor 2 (PAR2) Induces Long-Term Depression in the Hippocampus through Transient Receptor Potential Vanilloid 4 (TRPV4). Front Mol Neurosci 2017; 10:42. [PMID: 28303089 PMCID: PMC5332813 DOI: 10.3389/fnmol.2017.00042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 02/07/2017] [Indexed: 11/25/2022] Open
Abstract
Protease activated receptors (PARs) are involved in regulating synaptic transmission and plasticity in the brain. While it is well-accepted that PAR1 mediates long-term potentiation (LTP) of excitatory synaptic strength, the role of PAR2 in synaptic plasticity remains not well-understood. In this study, we assessed the role of PAR2-signaling in plasticity at hippocampal Schaffer collateral-CA1 synapses. Using field potential recordings, we report that PAR2-activation leads to long-term depression (LTD) of synaptic transmission through a protein kinase A -dependent, Transient Receptor Potential Vanilloid 4 -mediated mechanism, which requires the activation of N-methyl-D-aspartate receptors. These results demonstrate that the effects of PAR2 on synaptic plasticity are distinct from what is observed upon PAR1-activation. Thus, we propose that the activation of different classes of PARs, i.e., PAR1 and PAR2, may set the threshold of synaptic plasticity in the hippocampal network by balancing LTP and LTD.
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Journal Article |
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14
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Lenz M, Shimon MB, Benninger F, Neufeld MY, Shavit-Stein E, Vlachos A, Maggio N. Systemic thrombin inhibition ameliorates seizures in a mouse model of pilocarpine-induced status epilepticus. J Mol Med (Berl) 2019; 97:1567-1574. [PMID: 31667526 DOI: 10.1007/s00109-019-01837-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 10/25/2022]
Abstract
Status epilepticus (SE) is a life-threatening condition characterized by ongoing seizure activity which can lead to severe brain damage and death if not treated properly. Recent work suggests that alterations in blood-brain barrier (BBB) function and subsequent cortical exposure to coagulation factors may initiate, promote, and/or sustain SE. This suggestion is based on the observation that the serine protease thrombin, which plays a fundamental role in the blood coagulation cascade, increases neural excitability through the activation of protease-activated receptor 1 (PAR1). However, it remains unclear whether systemic inhibition of thrombin asserts "anti-epileptic" effects in vivo. We here used the pilocarpine model of SE in adult 3-month-old male mice to address the question whether intraperitoneal injection of the thrombin inhibitor α-NAPAP (0.75 mg/kg) counters SE. Indeed, pharmacological inhibition of thrombin ameliorates the behavioral outcome of pilocarpine-induced SE. Similar results are obtained when the thrombin receptor PAR1 is pharmacologically blocked using intraperitoneal injection of SCH79797 (25 μg/kg) prior to SE induction. Consistent with these results, an increase in thrombin immunofluorescence is detected in the hippocampus of pilocarpine-treated animals. Moreover, increased hippocampal serine protease activity is detected 90 min after SE induction, which is not observed in animals treated with α-NAPAP prior to SE induction. Together, these results corroborate and extend recent studies suggesting that novel oral anticoagulants which target thrombin (and PAR1) may assert anti-epileptic effects in vivo. KEY MESSAGES: Systemic thrombin/PAR1-inhibition ameliorates anticoagulants behavioral seizures. Status epilepticus increases thrombin levels in the hippocampus. Increased serine protease activity in the hippocampus after status epileptic. Anti-epileptic potential of clinically used anticoagulants must be evaluated.
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Research Support, Non-U.S. Gov't |
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Shapira S, Boustanai I, Kazanov D, Ben Shimon M, Fokra A, Arber N. Innovative dual system approach for selective eradication of cancer cells using viral-based delivery of natural bacterial toxin-antitoxin system. Oncogene 2021; 40:4967-4979. [PMID: 34172933 PMCID: PMC8342310 DOI: 10.1038/s41388-021-01792-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/30/2021] [Accepted: 04/12/2021] [Indexed: 01/20/2023]
Abstract
The inactivation of p53, a tumor suppressor, and the activation of the RAS oncogene are the most frequent genetic alterations in cancer. We have shown that a unique E. coli MazF-MazE toxin–antitoxin (TA) system can be used for selective and effective eradication of RAS-mutated cancer cells. This out of the box strategy holds great promise for effective cancer treatment and management. We provide proof of concept for a novel platform to selectively eradicate cancer cells using an adenoviral delivery system based on the adjusted natural bacterial system. We generated adenoviral vectors carrying the mazF toxin (pAdEasy-Py4-SV40mP-mCherry-MazF) and the antitoxin mazE (pAdEasy-RGC-SV40mP-MazE-IRES-GFP) under the regulation of RAS and p53, resp. The control vector carries the toxin without the RAS-responsive element (pAdEasy-ΔPy4-SV40mP-mCherry-MazF). In vitro, the mazF-mazE TA system (Py4-SV40mP-mCherry-MazF+RGC-SV40mP-MazE-IRES-GFP) induced massive, dose-dependent cell death, at 69% compared to 19% for the control vector, in a co-infected HCT116 cell line. In vivo, the system caused significant tumor growth inhibition of HCT116 (KRASmut/p53mut) tumors at 73 and 65% compared to PBS and ΔPY4 control groups, resp. In addition, we demonstrate 65% tumor growth inhibition in HCT116 (KRASmut/p53wt) cells, compared to the other two control groups, indicating a contribution of the antitoxin in blocking system leakage in WT RAS cells. These data provide evidence of the feasibility of using mutations in the p53 and RAS pathway to efficiently kill cancer cells. The platform, through its combination of the antitoxin (mazE) with the toxin (mazF), provides effective protection of normal cells from basal low activity or leakage of mazF.
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Shavit-Stein E, Dori A, Shimon MB, Gofrit SG, Maggio N. Prolonged Systemic Inflammation Alters Muscarinic Long-Term Potentiation (mLTP) in the Hippocampus. Neural Plast 2021; 2021:8813734. [PMID: 33510779 PMCID: PMC7822657 DOI: 10.1155/2021/8813734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/30/2020] [Accepted: 01/05/2021] [Indexed: 11/21/2022] Open
Abstract
The cholinergic system plays a fundamental role in learning and memory. Pharmacological activation of the muscarinic receptor M1R potentiates NMDA receptor activity and induces short-term potentiation at the synapses called muscarinic LTP, mLTP. Dysfunction of cholinergic transmission has been detected in the settings of cognitive impairment and dementia. Systemic inflammation as well as neuroinflammation has been shown to profoundly alter synaptic transmission and LTP. Indeed, intervention which is aimed at reducing neuroinflammatory changes in the brain has been associated with an improvement in cognitive functions. While cognitive impairment caused either by cholinergic dysfunction and/or by systemic inflammation suggests a possible connection between the two, so far whether systemic inflammation affects mLTP has not been extensively studied. In the present work, we explored whether an acute versus persistent systemic inflammation induced by LPS injections would differently affect the ability of hippocampal synapses to undergo mLTP. Interestingly, while a short exposure to LPS resulted in a transient deficit in mLTP expression, a longer exposure persistently impaired mLTP. We believe that these findings may be involved in cognitive dysfunctions following sepsis and possibly neuroinflammatory processes.
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Shimon V, Dedukh N, Meklesh Y, Shimon M, Ulyanichich N. [BONE REGENERATION AFTER THE FILLING OF DEFECTS BY GRANULES OF CERAMIC BIOMATERIAL BIOMIN TGG-2]. GEORGIAN MEDICAL NEWS 2020:170-177. [PMID: 32535584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Purpose of the study - to study the features of bone regeneration under conditions of filling metadiaphyseal defects with granules of biphasic calcium phosphate with β-tricalcium phosphate of a needle structure. The study was conducted on 24 white laboratory rats. А metadiaphyseal defect (3 mm) was reproduced in the distal femur with dental boron, followed by its filling with granules of TGg-2 ceramic biomaterial. Rats were removed from the experiment on days 7, 14, 28, and 56; histological methods examined the area of the defect filled with granules. Bone regeneration in a defect filled with granules proceeds in accordance with the general characteristics of reparative osteogenesis. There is a sequence of tissues formation, fibroreticular and bone, with a subsequent increase in the area and maturity of bone tissue for the duration of the study. Bone tissue was formed directly on the surface and between the granules, for a finite period (56 days) 2.2 times the area of fibroreticular tissue. Granules in the defect occupied more than 60% of its area. A characteristic feature was a pronounced macrophage reaction and resorption of granules by multinucleated cells, defined as osteoclasts. Biomin TGg-2, a new ceramic biomaterial, is biphasic calcium phosphate with a composition of needle-shaped hydroxylapatite and β-tricalcium phosphate, has biocompatible and high osteoconductive qualities, as evidenced by the location of fibroblasts and osteoblasts on the surface of the granules and the formation of bone tissue directly on the granules. The biomaterial does not cause a chronic inflammatory reaction.
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Shapira S, Kazanov D, Ben Shimon M, Hay Levy M, Mdah F, Asido S, Carmel N, Yossepowitch O, Grisaru D, Fliss D, Isakov O, Lahat G, Nachmany I, Gluck N, Peer M, Wolf I, Arber N. The dark age of single organ screening is over: CD24 is a novel universal simple blood test for early detection of cancer. J Clin Oncol 2020. [DOI: 10.1200/jco.2020.38.15_suppl.e15591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e15591 Background: More than 1.8 million new cancer cases are expected to be diagnosed in 2020. Only in the U.S, about 606,520 Americans are expected to die this year, which translates to about 1,660 deaths per day. However, when found early, in the asymptomatic phase, cancer is often effectively treated or even cured. The few cancer screens available today, including mammograms and colonoscopies, each look for a single type of cancer. CD24 is hardly expressed in normal cells (but to B-lymphocytes, differentiating neuroblasts and neutrophils) but is overexpressed in numerous human cancers. Aim: To establish a universal cancer screening blood test. Methods: Blood samples were obtained from consecutive patients and healthy volunteers. 1x106 leukocytes were stained using anti-CD11b-PerCp-Cy5.5 and anti-CD24-FITC and analyzed by flow cytometry (CyFlow Cube 6, Sysmex, Germany). Percentage of positive cells was determined by subtracting the percentage of CD24 and CD11b-positive cells (dual stain) from CD24-positive cells (single stain). The cut off for cancer detection was 25. Healthy subjects underwent a thorough evaluation at the health promotion center and integrated cancer prevention center. All cancers were verified histologically. Results: CD24/CD11b expression in the healthy population was evaluated in 337 women and 408 men, ages 20-85. There were 222 cancer patients. After excluding thyroid and bladder cancers, the assay detected 146 out of 196 (75%) cancers at all stages and even in 31 out of colonic adenomas (table). The levels of CD24 drop back to near normal level following successful surgery/chemotherapy. The test score was not affected by age, gender, fasting and the time of the day that the blood sample is taken. In 55 cases the test was performed twice, with similar results, as well as when the test was performed in another flow cytometry, after 1d, 1w, 1m after freezing . Conclusions: 1. CD24 is a universal cancer screening. 2. It can detect pre malignant lesions like adenomas in the colon. 3. Preliminary results suggest that it can serve as a predictive marker. [Table: see text]
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