Academic literature on the topic 'Calpain 2'
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Journal articles on the topic "Calpain 2"
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Upla, Paula, Varpu Marjomäki, Liisa Nissinen, Camilla Nylund, Matti Waris, Timo Hyypiä, and Jyrki Heino. "Calpain 1 and 2 Are Required for RNA Replication of Echovirus 1." Journal of Virology 82, no. 3 (November 21, 2007): 1581–90. http://dx.doi.org/10.1128/jvi.01375-07.
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ABSTRACT Calpains are calcium-dependent cysteine proteases that degrade cytoskeletal and cytoplasmic proteins. We have studied the role of calpains in the life cycle of human echovirus 1 (EV1). The calpain inhibitors, including calpeptin, calpain inhibitor 1, and calpain inhibitor 2 as well as calpain 1 and calpain 2 short interfering RNAs, completely blocked EV1 infection in the host cells. The effect of the inhibitors was not specific for EV1, because they also inhibited infection by other picornaviruses, namely, human parechovirus 1 and coxsackievirus B3. The importance of the calpains in EV1 infection also was supported by the fact that EV1 increased calpain activity 3 h postinfection. Confocal microscopy and immunoelectron microscopy showed that the EV1/caveolin-1-positive vesicles also contain calpain 1 and 2. Our results indicate that calpains are not required for virus entry but that they are important at a later stage of infection. Calpain inhibitors blocked the production of EV1 particles after microinjection of EV1 RNA into the cells, and they effectively inhibited the synthesis of viral RNA in the host cells. Thus, both calpain 1 and calpain 2 are essential for the replication of EV1 RNA.
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Wang, Yubin, Yan Liu, Xiaoning Bi, and Michel Baudry. "Calpain-1 and Calpain-2 in the Brain: New Evidence for a Critical Role of Calpain-2 in Neuronal Death." Cells 9, no. 12 (December 16, 2020): 2698. http://dx.doi.org/10.3390/cells9122698.
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Calpains are a family of soluble calcium-dependent proteases that are involved in multiple regulatory pathways. Our laboratory has focused on the understanding of the functions of two ubiquitous calpain isoforms, calpain-1 and calpain-2, in the brain. Results obtained over the last 30 years led to the remarkable conclusion that these two calpain isoforms exhibit opposite functions in the brain. Calpain-1 activation is required for certain forms of synaptic plasticity and corresponding types of learning and memory, while calpain-2 activation limits the extent of plasticity and learning. Calpain-1 is neuroprotective both during postnatal development and in adulthood, while calpain-2 is neurodegenerative. Several key protein targets participating in these opposite functions have been identified and linked to known pathways involved in synaptic plasticity and neuroprotection/neurodegeneration. We have proposed the hypothesis that the existence of different PDZ (PSD-95, DLG and ZO-1) binding domains in the C-terminal of calpain-1 and calpain-2 is responsible for their association with different signaling pathways and thereby their different functions. Results with calpain-2 knock-out mice or with mice treated with a selective calpain-2 inhibitor indicate that calpain-2 is a potential therapeutic target in various forms of neurodegeneration, including traumatic brain injury and repeated concussions.
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Ben-Aharon, Irit, Paula R. Brown, Nir Etkovitz, Edward M. Eddy, and Ruth Shalgi. "The expression of calpain 1 and calpain 2 in spermatogenic cells and spermatozoa of the mouse." Reproduction 129, no. 4 (April 2005): 435–42. http://dx.doi.org/10.1530/rep.1.00255.
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There is some evidence suggesting that Ca2+is involved in processes that occur during the development and function of spermatozoa. Calcium-dependent proteins, such as calmodulin, are expressed during mammalian spermatogenesis further suggesting that Ca2+takes part in its regulation. However, the precise roles of Ca2+in spermatogenesis remain to be elucidated. Calpains are a family of Ca2+-dependent cysteine proteases whose members are expressed ubiquitously or in a tissue-specific manner. Calpain has been demonstrated to mediate specific Ca2+-dependent processes including cell fusion, mitosis and meiosis. We herein followed the expression pattern of calpain’s ubiquitous isoforms, 1 and 2, throughout spermatogenesis at the RNA and protein levels by RT-PCR and Western blotting analysis. Both RNA and protein studies revealed that these isoforms are expressed in all spermatogenic cells. The expression of calpain 1 levels is slightly higher in spermatocytes entering the meiotic phase. Both calpain isoforms are also expressed in mouse spermatozoa and are localized to the acrosomal cap. Inducing capacitated spermatozoa to undergo the acrosome reaction in the presence of a selective calpain inhibitor significantly reduced the acrosome reaction rate in a dose-dependent manner. Thus, calpain, a pluripotential protease with numerous substrates, may serve as an effector in more than one pathway in the complex process of spermatogenesis and in the events preceding fertilization, such as the acrosome reaction.
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Baudry, Michel. "Calpain-1 and Calpain-2 in the Brain: Dr. Jekill and Mr Hyde?" Current Neuropharmacology 17, no. 9 (August 22, 2019): 823–29. http://dx.doi.org/10.2174/1570159x17666190228112451.
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While the calpain system has now been discovered for over 50 years, there is still a paucity of information regarding the organization and functions of the signaling pathways regulated by these proteases, although calpains play critical roles in many cell functions. Moreover, calpain overactivation has been shown to be involved in numerous diseases. Among the 15 calpain isoforms identified, calpain-1 (aka µ-calpain) and calpain-2 (aka m-calpain) are ubiquitously distributed in most tissues and organs, including the brain. We have recently proposed that calpain-1 and calpain- 2 play opposite functions in the brain, with calpain-1 activation being required for triggering synaptic plasticity and neuroprotection (Dr. Jekill), and calpain-2 limiting the extent of plasticity and being neurodegenerative (Mr. Hyde). Calpain-mediated cleavage has been observed in cytoskeleton proteins, membrane-associated proteins, receptors/channels, scaffolding/anchoring proteins, and protein kinases and phosphatases. This review will focus on the signaling pathways related to local protein synthesis, cytoskeleton regulation and neuronal survival/death regulated by calpain-1 and calpain-2, in an attempt to explain the origin of the opposite functions of these 2 calpain isoforms. This will be followed by a discussion of the potential therapeutic applications of selective regulators of these 2 calpain isoforms.
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McCartney, Christian-Scott E., Qilu Ye, Robert L. Campbell, and Peter L. Davies. "Insertion sequence 1 from calpain-3 is functional in calpain-2 as an internal propeptide." Journal of Biological Chemistry 293, no. 46 (September 25, 2018): 17716–30. http://dx.doi.org/10.1074/jbc.ra118.004803.
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Calpains are intracellular, calcium-activated cysteine proteases. Calpain-3 is abundant in skeletal muscle, where its mutation-induced loss of function causes limb-girdle muscular dystrophy type 2A. Unlike the small subunit–containing calpain-1 and -2, the calpain-3 isoform homodimerizes through pairing of its C-terminal penta-EF-hand domain. It also has two unique insertion sequences (ISs) not found in the other calpains: IS1 within calpain-3's protease core and IS2 just prior to the penta-EF-hand domain. Production of either native or recombinant full-length calpain-3 to characterize the function of these ISs is challenging. Therefore, here we used recombinant rat calpain-2 as a stable surrogate and inserted IS1 into its equivalent position in the protease core. As it does in calpain-3, IS1 occupied the catalytic cleft and restricted the enzyme's access to substrate and inhibitors. Following activation by Ca2+, IS1 was rapidly cleaved by intramolecular autolysis, permitting the enzyme to freely accept substrate and inhibitors. The surrogate remained functional until extensive intermolecular autoproteolysis inactivated the enzyme, as is typical of calpain-2. Although the small-molecule inhibitors E-64 and leupeptin limited intermolecular autolysis of the surrogate, they did not block the initial intramolecular cleavage of IS1, establishing its role as a propeptide. Surprisingly, the large-molecule calpain inhibitor, calpastatin, completely blocked enzyme activity, even with IS1 intact. We suggest that calpastatin is large enough to oust IS1 from the catalytic cleft and take its place. We propose an explanation for why calpastatin can inhibit calpain-2 bearing the IS1 insertion but cannot inhibit WT calpain-3.
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Covington, Marisa D., David D. Arrington, and Rick G. Schnellmann. "Calpain 10 is required for cell viability and is decreased in the aging kidney." American Journal of Physiology-Renal Physiology 296, no. 3 (March 2009): F478—F486. http://dx.doi.org/10.1152/ajprenal.90477.2008.
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Aging is associated with abnormalities in kidney function, but the exact mechanisms are unknown. We examined calpains 1, 2, and 10 protein levels in kidneys from rats, mice, and humans of various ages and determined whether calpain 10 is required for cell viability. Calpain 10 protein expression decreased in the kidney, but not in the liver, of aging Fischer 344 rats, and this decrease was attenuated with caloric restriction. There was no change in calpains 1 or 2 levels in the kidney or liver in control and caloric-restricted aging rats. Aging mice also exhibited decreased calpain 10 protein levels. Calpain 10 protein and mRNA levels decreased linearly in human kidney samples with age in the absence of changes in calpains 1 or 2. Our laboratory previously found calpain 10 to be expressed in both the cytosol and mitochondria of rabbit renal proximal tubular cells (RPTC). Adenoviral-delivered shRNA to rabbit RPTC decreased mitochondrial calpain 10 expression below detectable levels by 3 days while cytosolic calpain 10 levels remained unchanged at 3 days and decreased to ∼20% of control by 5 days. Knockdown of mitochondrial calpain 10 resulted in nuclear condensation and cleaved procaspase 3, markers of apoptosis. In summary, mitochondrial calpain 10 is required for cell viability and calpain 10 levels specifically decrease in aging rat, mice, and human kidney tissues when renal function decreases, suggesting that calpain 10 is required for renal function and is a biomarker of the aging kidney.
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Muniappan, Latha, Michihiro Okuyama, Aida Javidan, Devi Thiagarajan, Weihua Jiang, Jessica J. Moorleghen, Lihua Yang, et al. "Inducible Depletion of Calpain-2 Mitigates Abdominal Aortic Aneurysm in Mice." Arteriosclerosis, Thrombosis, and Vascular Biology 41, no. 5 (May 5, 2021): 1694–709. http://dx.doi.org/10.1161/atvbaha.120.315546.
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Objective: Cytoskeletal structural proteins maintain cell structural integrity by bridging extracellular matrix with contractile filaments. During abdominal aortic aneurysm (AAA) development, (1) aortic medial degeneration is associated with loss of smooth muscle cell integrity and (2) fibrogenic mesenchymal cells mediate extracellular matrix remodeling. Calpains cleave cytoskeletal proteins that maintain cell structural integrity. Pharmacological inhibition of calpains exert beneficial effects on Ang II (angiotensin II)–induced AAAs in LDLR −/− (low-density receptor deficient) mice. Here, we evaluated the functional contribution of fibrogenic mesenchymal cells-derived calpain-2 on (1) cytoskeletal structural protein and extracellular matrix alterations and (2) AAA progression. Approach and Results: Calpain-2 protein and cytoskeletal protein (filamin and talin) fragmentation are significantly elevated in human and Ang II–induced AAAs in mice. To examine the relative contribution of calpain-2 in AAA development, calpain-2 floxed mice in an LDLR −/− background were bred to mice with a tamoxifen-inducible form of Cre under control of either the ubiquitous promoter, chicken β-actin, or fibrogenic mesenchymal cell-specific promoter, Col1α2 (collagen type 1 alpha 2). Ubiquitous or fibrogenic mesenchymal cell-specific depletion of calpain-2 in mice suppressed Ang II–induced AAAs, filamin/talin fragmentation, while promoting extracellular matrix protein, collagen in the aortas. Calpain-2 silencing in aortic smooth muscle cells or fibroblasts reduced Ang II–induced filamin fragmentation. In addition, silencing of filamin in aortic SMCs significantly reduced collagen protein. Furthermore, calpain-2 deficiency suppressed rupture of established Ang II–induced AAAs in mice. Conclusions: Our studies implicate that calpain-2 deficiency prevents (1) Ang II–induced cytoskeletal structural protein fragmentation and AAA development and (2) stabilize and suppress rupture of established AAAs in mice.
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Murphy, Robyn M., Rodney J. Snow, and Graham D. Lamb. "μ-Calpain and calpain-3 are not autolyzed with exhaustive exercise in humans." American Journal of Physiology-Cell Physiology 290, no. 1 (January 2006): C116—C122. http://dx.doi.org/10.1152/ajpcell.00291.2005.
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μ-calpain and calpain-3 are Ca2+-dependent proteases found in skeletal muscle. Autolysis of calpains is observed using Western blot analysis as the cleaving of the full-length proteins to shorter products. Biochemical assays suggest that μ-calpain becomes proteolytically active in the presence of 2–200 μM Ca2+. Although calpain-3 is poorly understood, autolysis is thought to result in its activation, which is widely thought to occur at lower intracellular Ca2+ concentration levels ([Ca2+]i; ∼1 μM) than the levels at which μ-calpain activation occurs. We have demonstrated the Ca2+-dependent autolysis of the calpains in human muscle samples and rat extensor digitorum longus (EDL) muscles homogenized in solutions mimicking the intracellular environment at various [Ca2+] levels (0, 2.5, 10, and 25 μM). Autolysis of calpain-3 was found to occur across a [Ca2+] range similar to that for μ-calpain, and both calpains displayed a seemingly higher Ca2+ sensitivity in human than in rat muscle homogenates, with ∼15% autolysis observed after 1-min exposure to 2.5 μM Ca2+ in human muscle and almost none after 1- to 2-min exposure to the same [Ca2+]i level in rat muscle. During muscle activity, [Ca2+]i may transiently peak in the range found to autolyze μ-calpain and calpain-3, so we examined the effect of two types of exhaustive cycling exercise (30-s “all-out” cycling, n = 8; and 70% V̇o2 peak until fatigue, n = 3) on the amount of autolyzed μ-calpain or calpain-3 in human muscle. No significant autolysis of μ-calpain or calpain-3 occurred as a result of the exercise. These findings have shown that the time- and concentration-dependent changes in [Ca2+]i that occurred during concentric exercise fall near but below the level necessary to cause autolysis of calpains in vivo.
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Piper, Ann-Katrin, Reece A. Sophocleous, Samuel E. Ross, Frances J. Evesson, Omar Saleh, Adam Bournazos, Joe Yasa, et al. "Loss of calpains-1 and -2 prevents repair of plasma membrane scrape injuries, but not small pores, and induces a severe muscular dystrophy." American Journal of Physiology-Cell Physiology 318, no. 6 (June 1, 2020): C1226—C1237. http://dx.doi.org/10.1152/ajpcell.00408.2019.
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The ubiquitous calpains, calpain-1 and -2, play important roles in Ca2+-dependent membrane repair. Mechanically active tissues like skeletal muscle are particularly reliant on mechanisms to repair and remodel membrane injury, such as those caused by eccentric damage. We demonstrate that calpain-1 and -2 are master effectors of Ca2+-dependent repair of mechanical plasma membrane scrape injuries, although they are dispensable for repair/removal of small wounds caused by pore-forming agents. Using CRISPR gene-edited human embryonic kidney 293 (HEK293) cell lines, we established that loss of both calpains-1 and -2 ( CAPNS1−/−) virtually ablates Ca2+-dependent repair of mechanical scrape injuries but does not affect injury or recovery from perforation by streptolysin-O or saponin. In contrast, cells with targeted knockout of either calpain-1 ( CAPN1−/−) or -2 ( CAPN2−/−) show near-normal repair of mechanical injuries, inferring that both calpain-1 and calpain-2 are equally capable of conducting the cascade of proteolytic cleavage events to reseal a membrane injury, including that of the known membrane repair agent dysferlin. A severe muscular dystrophy in a murine model with skeletal muscle knockout of Capns1 highlights vital roles for calpain-1 and/or -2 for health and viability of skeletal muscles not compensated for by calpain-3 ( CAPN3). We propose that the dystrophic phenotype relates to loss of maintenance of plasma membrane/cytoskeletal networks by calpains-1 and -2 in response to directed and dysfunctional Ca2+-signaling, pathways hyperstimulated in the context of membrane injury. With CAPN1 variants associated with spastic paraplegia, a severe dystrophy observed with muscle-specific loss of calpain-1 and -2 activity identifies CAPN2 and CAPNS1 as plausible candidate neuromuscular disease genes.
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Theopold, U., M. Pintér, S. Daffre, Y. Tryselius, P. Friedrich, D. R. Nässel, and D. Hultmark. "CalpA, a Drosophila calpain homolog specifically expressed in a small set of nerve, midgut, and blood cells." Molecular and Cellular Biology 15, no. 2 (February 1995): 824–34. http://dx.doi.org/10.1128/mcb.15.2.824.
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Calpains are calcium-dependent proteases believed to participate in calcium-regulated signal pathways in cells. Ubiquitous calpains as well as tissue-specific calpains have been found in vertebrates. We isolated cDNA clones for a highly tissue-specific calpain gene from Drosophila melanogaster, CalpA, at 56C-D on the second chromosome. The expression of the CalpA gene product was monitored by using a specific antiserum directed against the product expressed by one cDNA clone. The encoded protein is found in a few neurons in the central nervous system, in scattered endocrine cells in the midgut, and in blood cells. In the blood cell line mbn-2, calpain is associated with a granular component in the cytoplasm. The expression of this protein is more restricted than that of the corresponding transcripts, which are widely distributed in the central nervous system, digestive tract, and other tissues. The sequence of CalpA is closely related to that of vertebrate calpains, but an additional segment is inserted in the calmodulin-like carboxy-terminal domain. This insert contains a hydrophobic region that may be involved in membrane attachment of the enzyme. Differential splicing also gives rise to a minor transcript that lacks the calmodulin-like domain.
Dissertations / Theses on the topic "Calpain 2"
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Mendes, Atlante Silva. "Verapamil diminui a expressão proteica de calpaína-1 e metaloproteinase de matriz-2 na hipertrofia cardíaca induzida por hipertensão renovascular." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/17/17133/tde-08112018-150232/.
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Introdução: A hipertrofia cardíaca induzida por sobrecarga hemodinâmica crônica (HC) é caracterizada por espessamento das paredes do ventrículo esquerdo e do tecido intersticial. As atividades aumentadas de calpaína-1 e metaloproteinase de matriz(MMP)-2 são observadas em diferentes modelos de hipertensão arterial e estão relacionadas com as mudanças fisiopatológicas na HC. Por outro lado, a atividade de MMP-2 parece ser modulada positivamente por ativação de calpaína-1 em diferentes modelos. O objetivo deste trabalho é analizar se a calpaína-1 contribui para o aumento da atividade de MMP-2 no coração e se esse mecanismo resulta nas mudanças crônicas cardíacas na hipertensão renovascular. Métodos: Ratos Wistar submetidos ao modelo de 2-rins-1 clipe (2R-1C)(180-200g) e seus respectivos controles (Sham) foram tratados com verapamil (VRP), um bloqueador de canais para cálcio tipo L (BCCL, 8mg/kg/bid) ou veículo durante 8 semanas. O BCCL reduz as concentrações intracelulares de cálcio, o que leva à diminuição da ativação de calpaína-1, e então à possível modulação da atividade e expressão proteica de MMP-2. Pressão arterial sistólica (PAS) dos ratos foi monitorada durante 10 semanas de hipertensão por pletismografia de cauda. O ventrículo esquerdo (VE) foi analisado por histologia e ecocardiografia para avaliação das dimensões ventriculares. A atividade de calpaína-1 e MMP-2 foi avaliada por zimografia em gel. A expessão proteica de calpaína-1 e MMP-2 foi avaliada por western blot e imunofluorescência. Os corações foram submetidos à avaliação funcional por Langendorff. Todos os protocolos foram aprovados pelo Comitê de Ética em Pesquisa Animal da Faculdade de Medicina de Ribeirão Preto (43/2017). Resultados: Após 10 semanas, a PAS teve um aumento sustentado nos animais 2R-1C e o tratamento com VRP não foi capaz de reduzí-la em nenhum tempo de hipertensão. O peso corporal não apresentou diferença significativa entre os grupos. O grupo hipertenso teve um aumento da massa cardíaca quando comparado ao sham e o tratamento com verapamil reduziu esse parâmetro. A análise da espessura do ventrículo esquerdo demonstra que o VRP é capaz de reverter a HC induzida por sobrecarga pressórica nos animais hipertensos. Os animais 2R-1C apresentaram um aumento singificativo na expressão proteica e atividade de calpaína-1 e o VRP foi capaz de diminuir esses níveis. Foi observado aumento da atividade das isoformas de MMP-2 nos ratos 2R-1C quando comparados aos controles e o VRP foi capaz de reduzir a atividade da isoforma de 64kDa. A contratilidade cardíaca intrínseca dos animais 2R-1C sugere uma disfunção cardíaca quando comparados aos controles sham, embora a fração de ejeção desses animais esteja preservada. O VRP não foi capaz de alterar esses parâmetros. Conclusão: O VRP pode contribuir para a redução da hipertrofia cardíaca por diminuir a expressão proteica de calpaína-1 e MMP-2 na hipertensão renovascular. Apoio financeiro: Capes, CNPq, FAPESPIntroduction: The chronic hemodynamic overload-induced cardiac hypertrophy (CH) is characterized by thickening of the left ventricle walls and hypertrophy of the cardiomyocytes and interstitial tissue. Increased activity of calpain-1 and matrix metalloproteinase(MMP)-2 was observed in different models of arterial hypertension models and contributes to the pathophysiologic changes shown in CH. On the other hand, MMP-2 activity is also positively modulated by activation of calpain-1 in different animal models of cardiovascular diseases. The objectives here are to analyze whether calpain-1 contributes to increase the activity of MMP-2 in the heart and whether this mechanism results in chronic cardiac changes in the renovascular hypertension. Methods: Two kidney-one clip (2K1C) hypertensive male Wistar rats (180-200g) and their respective controls (Sham) were orally treated with verapamil (VRP), a L-type calcium channels blocker (LCCB, 8mg/kg/bid), or vehicle during 8 weeks. The LCCB reduces the intracellular concentration of calcium, thus decreasing the activation of calpain-1, and then may modulate the activity of MMP-2. Systolic blood pressure (SBP) was monitored in the rats during 10 weeks of hypertension. Left ventricle (LV) was analyzed by histology and echocardiography to evaluate ventricle thickening. Calpain- 1 and MMP-2 activities were analyzed by zymography and their expression by immunofluorescence and western blot. Hearts were submitted to functional evaluation by Langendorff. All the protocols were approved by the Ethical Committee in Animal Research of Ribeirao Preto Medical School (43/2017). Results: After 10 weeks, the systolic blood pressure had sustained increase and treatment with VRP was not able to decrease it in any time of hypertension. The body weight did not present significant changes between the groups. Hypertensive group had significant increase in the ventricle/body weight ratio (VW/BW) when compared to sham and treatment with VRP decreased it. Analysis of ventricle thickening showed that VRP is able to revert CHinduced pressure overload. The 2K-1C rats showed a significant increase in the activity and expression of calpain-1 in the heart and VRP reverted it. It was also observed increased activity of MMP-2 forms in the hypertensive rats and VRP decreased the 64kDa MMP-2 activity. The 2K-1C group had cardiac dysfunction when compared to controls groups, and VRP did not alter it. The ejection fraction was not changed in 2K- 1C rats. Conclusion: VRP decreased expression and activity of calpain-1 and MMP-2 in the hearts of 2K-1C rats and then contributed to ameliorate hypertension-induced cardiac hypertrophy
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Breiden, Maike [Verfasser], Michael [Akademischer Betreuer] Ehrmann, and Markus [Akademischer Betreuer] Kaiser. "Charakterisierung der Interaktion von HTRA1 und Calpain 2 / Maike Breiden. Gutachter: Markus Kaiser. Betreuer: Michael Ehrmann." Duisburg, 2014. http://d-nb.info/1058323385/34.
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Howells, Anwen. "The impact of innate immune cells on immunopathology in dengue." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:0a251372-4d0e-416d-ad3c-8e07e6729e1b.
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Dengue virus (DENV) is an arthropod-borne virus and has become a worldwide problem with steadily rising annual infection rates. Patients present with a range of symptoms from mild fever to, in some cases, life-threatening hemorrhagic fever and shock syndrome. The most severe cases require emergency hospital care and currently, there is no effective drug treatment or vaccine for dengue. As severe symptoms appear post-peak viremia, immuno-pathology is thought to be the cause and a potential trigger of this is differential activation of the immune response upon recognition of DENV. This could be due to a combination of factors including varying receptors, signalling pathways and immune regulation mechanisms. In order to understand DENV infection better, it is imperative to study the mechanisms of activation and control of immune responses triggered by the virus. Very early events in viral infection (after 10 min stimulation) were studied aiming to identify proteins involved in differential activation of immune responses. Phosphorylated proteins were isolated from cells post-stimulation and analysed by mass spectrometry. More than 200 proteins were differentially regulated by phosphorylation in response to DENV stimulation as compared to Mock, Influenza A virus and LPS stimulation. The effect of two specific proteins, namely Calpain-2 and Importin-5, identified to be differentially phosphorylated was investigated further. Calpain-2 was seen to be vital in the efficient production of progeny virions and the transcription of Mx1, an anti-viral interferon stimulated gene. Importin-5 is known to transport DENV NS5 into the nucleus during infection and was seen to co-precipitate with many host proteins. In summary, it is imperative that novel treatments and vaccines are developed for dengue as it is one of the worldâs most prevalent arthropod-borne viruses. It was discovered here that many proteins undergo phosphorylation/de-phosphorylation in response to DENV stimulation to a differing degree than other stimuli. Calpain-2 plays a vital role DENV infection, potentially influencing the potency of immune response. Importin-5 associates with various host proteins during DENV infection, potentially altering their function or the function of Importin-5 itself. Research into targeted inhibition of Calpain-2 function or Importin-5 interaction with DENV NS5 could lead to a successful anti-viral treatment for DENV infection.
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Liu, Tongzheng. "Regulation of Inflammtory Activation in Endothelial Cells by PIN1." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1242756227.
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Stroop, Davis M. "The Epidemiology of Early Type 2 Diabetes Mellitus in Black and White Females: Genetic and Environmental Factors." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1377870493.
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Sanchez, Brualla Irene. "The potassium-chloride cotransporter KCC2 : a new therapeutic target for spasticity and neuropathic pain." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0677.
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La spasticité et la douleur neuropathique sont deux symptômes apparaissant fréquemment après une lésion médullaire. La spasticité est définie comme une augmentation du tonus musculaire qui provoque des contractures, tandis que la douleur neuropathique se caractérise par des sensations douloureuses survenant suite à une lésion du système nerveux.Ces deux symptômes résultent en partie d’une désinhibition des réseaux neuronaux sous-lésionnels lié à une diminution de l’expression du cotransporteur potassium-chlorure type 2 (KCC2). Pour être efficace,l’inhibition nécessite l’action de cette protéine qui extrait les ions chlorure des neurones.L’objectif de la présente thèse est donc d’identifier des médicaments capables d’activer KCC2 afin de restaurer l’inhibition dans le but de traiter la spasticité et la douleur neuropathique.Dans un premier temps, nos résultats ont montré que l’activation de récepteurs sérotoninergiques 5-HT2A avec le TCB-2 rétablit l’expression de KCC2 dans la corne dorsale après une lésion médullaire ou névrectomie. Or le TCB-2 réduit seulement la douleur neuropathique après la lésion spinale.Par la suite, nous avons identifié la prochlorperazine comme une molécule augmentant l’activité de KCC2. Si la prochlorperazine est efficace contre la spasticité, elle a néanmoins un effet plus modeste envers l’allodynie mécanique suite à une lésion médullaire.Enfin, nous avons démontré que la diminution de KCC2,ainsi que l’hyperexcitabilité des motoneurones suite à la lésion, dépendent de l’activation des calpaïnes.Cette thèse valide KCC2 comme une cible thérapeutique dans le traitement de la spasticité et la douleur neuropathique suite à une lésion médullaireSpasticity and neuropathic pain are two symptoms that arise frequently after a spinal cord injury. Spasticity is defined as an increase of the muscle tone contributing to cramps, whereas neuropathic pain consists of painful responses caused by a damaged nervous system. Both symptoms arise, in part, due to a loss of inhibition in the sublesional neural networks, linked to a downregulation of the expression of potassium-chloride cotransporter type 2 (KCC2). For inhibition to be efficient, the action of this protein, which extrudes chloride ions from neurons, is needed.The objective of this thesis is, therefore, to identify drugs capable of activating KCC2 to recover inhibition with the objective of treating spasticity and neuropathic pain.First, our results have proven that the activation of serotonin receptors 5-HT2A with TCB-2 restores KCC2 expression in the dorsal horn after a spinal cord or peripheral nerve injury. However, TCB-2 reduces neuropathic pain after a spinal cord injury exclusively.In the next stage of the work, we have identified prochlorperazine as an enhancer of KCC2 activity. Prochlorperazine is efficient against spasticity, although it only showed a modest reduction of mechanical hyperalgesia in animals with a spinal cord injury.Lastly, we have proven that KCC2 downregulation and motoneuron hyperexcitability after a spinal cord injury depend on the overactivation of calpains.This thesis validates KCC2 as a druggable target to treat spasticity and neuropathic pain after spinal cord injury
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Muir, Matthew Stewart. "Proteomics of the ovine cataract." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/792.
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The lens of the eye needs to be completely transparent in order to allow all light entering the eye to reach the retina. This transparency is maintained by the highly ordered structure of the lens proteins the crystallins. Any disruption to the lens proteins can cause an opacity to develop which is known as cataract. During cortical cataract formation there is increased truncation of the lens crystallins. It is believed that overactivation of calcium-dependent cysteine proteases, the calpains, is responsible for the increased proteolysis of the crystallins seen during cataractogenesis. Within the ovine lens there are three calpains, calpain 1, 2 and the lens specific calpain Lp82. The aim of this thesis was to determine the changes in the lens proteins during ageing and cataractogenesis, and to establish the role of the calpains in these processes. Calpain 1 and 2 were purified from ovine lung and Lp82 was purified from lamb lenses using chromatography. Activity and presence of the calpains was determined by using the BODIPY-FL casein assay, gel electrophoresis, Western blot and casein zymography. Changes in the lens proteins, specifically the crystallins, were visualised using two-dimensional electrophoresis (2DE). Lenses from fetal, 6 month old and 8 year old sheep were collected, as well as stage 0, 1, 3 and 6 cataractous ovine lenses. The proteins from the lenses were separated into the water soluble and urea soluble fractions and analysed by 2DE. Mass spectrometry was used to determine the masses and therefore modifications of the crystallins. Finally, the individual crystallins were separated using gel filtration chromatography and incubated with the purified calpains in the presence of calcium. The extent of the proteolysis was visualised using 2DE and truncation sites determined by mass spectrometry. Purification of the calpains resulted in samples that were specific for each calpain and could be used in further experiments. 2DE analysis showed that there were changes to the crystallins during maturation of the lens. The α-crystallins become increasingly phosphorylated as the lens ages and a small amount becomes truncated. The β-crystallins were also modified during ageing by truncation and deamidation. When crystallins from cataractous lenses were compared using 2DE there were changes to both the α- and β-crystallins. The α-crystallins were found to be extensively truncated at their C-terminal tail. Four of the seven β-crystallins, βB1, βB3, βB2 and βA3, showed increased truncation of their N-terminal extensions during cataract formation. All three calpains truncated αA and αB-crystallin at their C-terminal ends after incubation. Calpain 2 and Lp82 each produced unique αA-crystallin truncations. All three calpains truncated βB1 and βA3 and calpain 2 also truncated βB3. When the truncations from the calpain incubations were compared to those seen during cataract formation, many of the truncations were found to be similar. Both the unique truncations from calpain 2 and Lp82 were found in cataractous lenses, with the Lp82 more obvious in the 2DE. The β-crystallin truncations found after incubation with the calpains were similar to those found during cataractogenesis. In conclusion this study documents the changes to the ovine lens during maturation and cataractogenesis and indicates a role for the calpain family in the increased proteolysis observed in the ovine cataract.
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Ruppert, Anne-Marie. "Rôle des calpaïnes extracellulaires dans la progression des adénocarcinomes lépidiques." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066317/document.
Full textAbstract:
La calpaïne 1 est une protéase à cystéine activée par le calcium, qui peut être partiellement externalisée. Les calpaines extracellulaires favorisent la résolution de l'inflammation et la réparation des tissus, à travers la prolifération et la migration cellulaire. Le récepteur Toll like (TLR) 2 a été identifié comme une cible des calpaïnes extracellulaires dans les lymphocytes. L'objectif est d'étudier le rôle de la calpaïne extracellulaire 1 dans la progression tumorale de l'adénocarcinome pulmonaire lepidique (ADL). La calpaïne extracellulaire, le fragment soluble de TLR2, le versican et les cytokines étaient analysés par ELISA dans des surnageants de lavage bronchoalvéolaire (LBA) de patients atteints d'ADL (n = 68). La source de calpaïne était analysée par immunohistochimie. TLR2, cible de la calpaïne extracellulaire était étudiée par cytométrie de flux sur les polynucléaires neutrophiles (PNN) et des lignées humaines de cancer bronchiques. Calpain 1 extracellulaire, sécrété par les cellules tumorales, était associée à la progression tumorale, l'inflammation à neutrophiles, avec un facteur de mauvais pronostic de survie (p = 0,003). TLR2 était exprimé sur les cellules tumorales ou les PNN avec une diminution d¿expression après traitement par calpaïne. Le fragment soluble de TLR2 était corrélée à la concentration extracellulaire de calpaïne 1 dans les surnageants de LBA (r = 0,624; p <0,001). Le fragment soluble de TLR2 élevé était associé à la progression tumorale et un environnement pro-inflammatoire La calpain extracellulaire sécrétée par la cellule tumorale, favorise un microenvironnement inflammatoire et la progression tumorale médiée par TLR2 dans ADLCalpain 1 is pro inflammatory calcium-activated cysteine proteases, which can be partly externalized. Extracellular calpains limit inflammatory processes and promote tissue repair, through cell proliferation and migration. Toll like receptor (TLR) 2 has been identified as a target of extracellular calpains in lymphocytes. The aim was to investigate the role of extracellular calpain 1 in tumor progression of lepidic pulmonary adenocarcinoma (LPA). Extracellular calpain 1, soluble fragment of TLR2 and cytokines were analyzed by ELISA in bronchoalveolar lavage fluid (BALF) supernatants from patients with LPA (n=68). Source of calpain was analyzed by immunohistochemistry. TLR2 as target of extracellular calpain was studied by flow cytometry on polymorphonuclear neutrophils (PMN) and human lung cancer cell lines. Extracellular Calpain 1, secreted by tumor cells, was associated to tumor progression, neutrophilic inflammation, with a poor prognostic factor on survival (p=0,003). TLR2 was expressed on PMN or tumor cells and decreased after calpain treatment. The soluble fragment of TLR2 was correlated to the extracellular calpain 1 concentration in the BALF supernatants (r=0.624; p<0.001). High soluble fragment of TLR2 was associated with tumor progression and a pro-inflammatory environment. Extracellular Calpain 1 secreted by tumor cell, promotes inflammatory microenvironment and tumor progression through TLR2 in LPA
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Hanna, Rachel. "REGULATION OF CALPAIN 2 BY CALPASTATIN." Thesis, 2010. http://hdl.handle.net/1974/5639.
Full textAbstract:
Calpains are a family of intracellular cysteine proteases activated by calcium. They participate in many processes including cell motility, cell cycle progression and cell death, in response to calcium signaling. Because calpain over-activation as a result of calcium dysregulation is a contributing factor to many disease states, these enzymes are important therapeutic targets. Within the cell, calpains 1 and 2 are regulated by the protein inhibitor calpastatin. This unstructured protein is specific for calpain, binds tightly, and recognizes only the activated form of the enzyme. Detailed kinetic data obtained using surface plasmon resonance allowed the association and dissociation rates of each of the four calpastatin inhibitory domains to be measured. Based on this, inhibitory domain 4 was selected to be co-crystallized bound to calpain 2. The X-ray crystal structure of this complex provided both the first view of the active enzyme, as well as the first view of how it is inhibited. Calpastatin wraps around the enzyme making contact with each domain. It lies in the active site as a contiguous polypeptide chain and escapes cleavage by forming a loop away from the catalytic cysteine. In addition to inhibiting substrate cleavage, calpastatin protects calpain in two ways; it prevents autoproteolysis, and it prevents calcium-dependent aggregation. The crystal structure of the calpastatin:calpain complex revealed no obvious reason for this stabilization. To elucidate how this protection occurs, peptides were synthesized corresponding to conserved subdomains of calpastatin. Surprisingly, each peptide alone was capable of preventing aggregation in vitro, by blocking hydrophobic patches exposed upon activation. The increased hydrophobic surface of the activated enzyme may alter calpain’s affinity for other proteins such as substrates. By binding across many domains of calpain, calpastatin could act to block protein-protein interactions. These studies have characterized calpastatin’s interaction with calpain, which will further our understanding of the enzyme’s regulation and aid in the development of better calpain inhibitors.Thesis (Ph.D, Biochemistry) -- Queen's University, 2010-04-29 15:27:16.208
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Lal, Sangeet Kumar. "Calpain 2 proteolysis regulates glioblastoma cell invasion." Thesis, 2010. http://hdl.handle.net/1957/19988.
Full textAbstract:
Glioblastoma is the most malignant primary brain tumor with the average
patients surviving only one year after diagnosis, even with aggressive therapy. The
formation of numerous micro-tumors dispersed into the brain due to rapid invasion of
tumor cells, presents the primary challenge to the surgical removal of tumors and
limits the effectiveness of current treatments. This dissertation presents studies aimed
at understanding the molecular mechanisms regulating invasion of human
glioblastoma cells. Transplantation of human glioblastoma cells in the zebrafish brain
showed that the knockdown of calpain 2, a calcium-activated protease, resulted in a
three fold decrease in the tumor cell invasion. The result was further verified in the
organotypic mouse brain slices where the knockdown cells demonstrated 2-fold
decrease in the area of dispersal compared to control cells. Our data show that calpain
2 plays a role in the process of tumor cell angiogenesis. Glioblastoma cells were
transplanted into the brain of zebrafish expressing GFP in the blood vessels and we
observed that 23% of animals injected with control tumor cells demonstrated
angiogenesis. In contrast, only 9% of fish that received calpain 2 knockdown cells
showed the formation of new vessels. Consistent to the reports from human
glioblastoma patients and rodent models, we did not observe metastasis of
transplanted cells outside of the brain in the zebrafish, supporting for the use of
zebrafish as an important model for glioblastoma cell invasion studies. These results
provide evidence that calpain 2 protease activity is required for the dispersal of
glioblastoma cells in the brain microenvironment. To determine the mechanism of
calpain 2 regulation of tumor cell invasion, proteolysis of filamin by calpain 2 was
studied.
Filamin is an important actin cross-linking protein which develops orthogonal
actin networks in the periphery of the cell. In this study, we show that the expression
of filamin inhibits glioblastoma cell invasion. Hence, knocking down filamin
expression by 80% resulted in 220% increase in the invasion of glioblastoma cells
through Matrigel extracellular matrix. The regulated proteolysis of filamin is a
potential mechanism to facilitate the cyclic turnover of actin orthogonal networks
which is required for glioblastoma cell invasion. In this study, we identified a novel
mechanism that the PI3 kinase activity regulates the cleavage of filamin by calpain 2
in glioblastoma cells. Binding of a membrane phospholipid phosphatidylinositol
(3,4,5) triphosphate [PtdIns (3,4,5)-P₃] to filamin induces its proteolysis by calpain 2
after the amino acid lysine 268, removing the actin binding domain which in-turn
abolishes the actin binding ability of filamin.Graduation date: 2011
Access restricted to the OSU Community at author's request from Jan. 31, 2011 - Jan. 31, 2012
Book chapters on the topic "Calpain 2"
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Carragher, Neil O. "Calpain." In Encyclopedia of Cancer, 1–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-27841-9_782-2.
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Biswas, Ashim Kumar, and Samarth Tandon. "Casein Zymography for Analysis of Calpain-1 and Calpain-2 Activity." In Methods in Molecular Biology, 31–38. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-8988-1_3.
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Biswas, Ashim Kumar, and Samarth Tandon. "Single-Step Purification of Calpain-1, Calpain-2, and Calpastatin Using Anion-Exchange Chromatography." In Methods in Molecular Biology, 3–11. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-8988-1_1.
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Pénisson-Besnier, I., I. Richard, F. Dubas, J. S. Beckmann, and M. Fardeau. "Exercise Intolerance in Calpain Deficiency and in α-Sarcoglycanopathy." In Exercise Intolerance and Muscle Contracture, 63–66. Paris: Springer Paris, 1999. http://dx.doi.org/10.1007/978-2-8178-0855-0_6.
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Sorimachi, Hiroyuki, Shoji Hata, and Yasuko Ono. "Calpain-2/m-Calpain." In Handbook of Proteolytic Enzymes, 2007–11. Elsevier, 2013. http://dx.doi.org/10.1016/b978-0-12-382219-2.00454-3.
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"Calpain-2." In Class 3 Hydrolases, 61–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-85705-1_7.
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Randriamboavonjy, Voahanginirina, and Ingrid Fleming. "The Role of Calpain in Diabetes-Associated Platelet Hyperactivation." In Cardiovascular Pharmacology - Heart and Circulation, 235–57. Elsevier, 2010. http://dx.doi.org/10.1016/s1054-3589(10)59008-2.
Full textConference papers on the topic "Calpain 2"
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Singh, Vinay K., Jacqueline C. Kelly, R. John MacLeod, and Zongchao Jia. "Abstract 4226: Curcumin induced CaSR stimulates calpain autolysis in colon cancer." In Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-4226.
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Supinski, Gerald S., Alexander Alimov, Lin Wang, Xiao-Hong Song, and Leigh Ann P. Callahan. "NSmase 2 Is Required For Infection Induced Skeletal Muscle Calpain Activation." In American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California. American Thoracic Society, 2012. http://dx.doi.org/10.1164/ajrccm-conference.2012.185.1_meetingabstracts.a2716.
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Colman, Robert W., Harlan Bradford, and Anjanayaki Annamalai. "FACTOR V IS ACTIVATED AND CLEAVED BY PLATELET CALPAIN: COMPARISON WITH THROMBIN PROTEOLYSIS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643884.
Full textAbstract:
Platelets are known to process human and bovine factor V during secretion and/or membrane binding. We therefore studied the functional and structural changes produced in human factor V and Va by purified platelet calpain. A maximum increase in factor V coagulant activity of 2.5-fold over control incubations was observed for calpain (0.6 u/ml) at 25°C in comparison with a 10-fold increment for a thrombin (1 u/ml). Thrombin addition to reactions initiated by calpain resulted in further activation comparable to that of thrombin alone, while subsequent addition of calpain had no effect on the extent or pattern of the activation of factor V by thrombin. The cleavage pattern of factor V produced by these two enzymes are distinctly different. Calpain yields initial components of 210 kDa and 160 kDa within 1 min. Further digestion of the 210 kDa species give rise to polypeptides of 150, 140 and 120 kDa by 2 min with and increase in coagulant activity. The degradation of the 160 kDa polypeptide gives rise to smaller fragments of 130, 100, 90, and 87 kDa. Immunob lot ting of these fragments with the monoclonal antibody B10 directed to factor V and the thrombin generated Cl fragments yields results demonstrating an immunological relationship to the calpain generated components of 210, 160, 140 and 120 kDa. Thus platelet calpain generates a complex cleavage pattern different from thrombin which may explain the partial activation observed.
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verhallen, P. F. J., E. M. Bevers, P. Comfurius, W. M. A. Linkskens, and R. F. A. Zwaal. "CALPAIN-MEDIATED CYTOSKELETAL DEGRADATION CORRELATES WITH STIMULATION OF PLATELET PROCOAGULANT ACTIVITY." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642821.
Full textAbstract:
We have shown earlier that the negatively charged phospholipid phosphatidylserine (PS), which becomes translocated from the inner surface to the outer surface of the plasma membrane upon platelet activation, is responsible for platelet procoagulant activity. Studies with erythrocytes have suggested a role for cytoskeletal proteins in the regulation of transmembrane asymmetry of PS. The possibility that platelet cytoskeletal proteins are involved in the loss of transmembrane asymmetry of PS, was explored by correlative investigations of both platelet prooagulant activity and activity of calpain, an endogenous Ca 2+ -dependent thiol-protease, known to hydrolyze major cytoskeletal proteins (e.g.: filamin, talin, myosin). Platelet procoagulant activity was assayed by determination of the prothrombinase activity under conditions at which the catalytic PS-surface was rate-limiting. Calpain-activity was monitored by the appearance of known degradation products of major cytoskeletal proteins. The following results were obtained: (1) The ability of thrombin, collagen, collagen & thrombin, or the Ca -ionophore A23187 to stimulate platelet procoagulant activity closely correlated with their ability to stimulate platelet calpain-activity (2). Generation of platelet procoagulant activity upon platelet stimulation by collagen & thrombin or by A23187 exhibited a time course identical to the development of calpain-activity. In addition, the local anesthetics dibucaine and tetracaine, shown to gradually stimulate calpain activity, were able to generate platelet procoagulant activity with a similar time course. (3) Using a Ca2+ buffering system and A23187 to equilibrate intracellular- and extracellular free Ca2+ , it was found that the Ca2+ -response relationship of both platelet calpain- and pro-coagulant-activity was identical. From these findings we conclude that the degradation of cytoskeletal proteins destroys their putative interactions with PS, enabling this lipid to participate in transbilayer movement, leading to the formation of a procoagulant outer surface of the platelet.
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Puri, R. N., F. Zhou, H. Bradford, E. J. Gustafson, R. F. Colman, and R. W. Colman. "HIGH MOLECULAR WEIGHT KININOGEN SPECIFICALLY BLOCKS THROMBIN-INDUCED AGGREGATION BY INHIBITING PLATELET CALPAIN." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643860.
Full textAbstract:
We have previously shown that platelet-aggregation induced by alpha-thrombin (1.7 nM) involves complete cleavage of the surface membrane polypeptide, Mr = 100 kDa (MP 100) labeled by FSBA in intact platelets. The failure to cleave MP100 in membrane preparations or in platelets treated with metabolic inhibitors or leupeptin, suggested that thrombin was acting by activating platelet calpain. Since high molecular weight kininogen (HMWK) is the most potent plasma inhibitor of calpain(s), we now report that HMWK inhibited thrombin-induced aggregation in a dose-dependent manner over a range of plasma concentrations. HMWK did not inhibit aggregation induced by ADP, collagen, U46619, A23187 and/or PMA. In order to study the action of HMWK in a plasma environment we utilized Y-thrombin. The aggregation induced by γ-thrombin (25 nM) in washed human platelets was also inhibited by HMWK. A much higher concentration of γ - thrombin (200 nM) was required to induce similar aggregation of platelets suspended in normal plasma. In contrast, γ -thrombin (50nM) induced complete aggregation of platelets suspended in plasma completely deficient in total kininogen indicating that a kininogen was predominently responsible for the inhibitory effect of plasma. When platelets were suspended in plasma deficient only in HMWK, aggregation required 75 nMY-thrombin. When plasma deficient in HMWK was supplemented with a physiological concentration of HMWK (0.67 μM) the aggregation of suspended washed platelets was similar to that in normal plasma. Finally, we found that purified platelet calpain-2 not only exposed fibrinogen binding sites and induced platelet aggregation, but also completely cleaved MP 100 in both intact platelets and membrane preparations. We conclude: a) Thrombin-induced platelet aggregation involves the indirect proteolytic cleavage of MP100 by activating calpain-2, and b) Inhibition of thrombin-induced platelet aggregation by HMWK involves specific inactivation of platelet calpain.
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Okita, J. R., M. M. Frojmovic, S. Kristopeit, T. Wong, and T. J. Kunicki. "MONTREAL PLATELET SYNDROME: DECREASED ACTIVITY OF PLATELET CALPAINS ASSOCIATED WITH AGGREGATION ABNORMALITIES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642822.
Full textAbstract:
The Montreal platelet syndrome (MPS) is an inherited disorder of platelet function characterized by a) severe thrombocytopenia, b) formation of "giant" platelets upon physical or biochemical stimulation, c) spontaneous aggregation (stir-induced microaggregate formation) and d) a lack of aggregation in response to thrombin. The Bernard-Soulier syndrome (BSS) is similar to MPS in that both syndromes are characterized by "giant" platelets and an abnormal aggregation response to thrombin. BSS patients have a deficiency of specific platelet glycoproteins (GPs). From our investigations we conclude MPS patients have apparently normal amounts of major platelet GPs. However, a defect in calpains (calcium-activated neutral proteinases) was detected in MPS platelets. The specific activity of calpains was decreased by 70% (p<0.001) in the cytosolic fraction of platelets from MPS patients as compared to that of platelets from normal control donors. The calpain activity of platelets from BSS patients was within the normal range.During the course of the biochemical studies, platelets from the MPS patients were shown to exhibit concurrent functional defects, i.e., stir-induced spontaneous aggregation and reduced to absent aggregation response to thrombin. It is concluded that MPS can be distinguished from BSS at the molecular level as follows: 1) MPS platelets contain normal amounts of GPs Ib, V and IX which are decreased or absent in BSS platelets; 2) The specific activity of calpains is reduced in MPS platelets but normal in BSS platelets. Supported by NIH (HL-33925, HL-32279), Amer. Heart Assoc. (85—GA—67, 83-186), Canadian Med. Res. Council (248-59) and Quebec Heart Fndn.
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Landowski, Terry H., Aluvia M. Escalante, Ryan McGrath, Matthew R. Karolak, Meredith Henderson, Georgia O. Perrian, and Ron Lynch. "Abstract 2643: Inhibition of calpain disrupts the autophagic response initiated by bortezomib resulting in increased death of myeloma cells." In Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-2643.
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Wallace, Robert W., E. Ann Tallant, and Lynn M. Brumley. "POSSIBLE ROLE FOR THE CA2+-DEPENDENT PROTEASE (CALPAIN I) AS AN IRREVERSIBLE ACTIVATOR OF CA2+/CALMODULIN-MEDIATED REACTIONS IN THE HUMAN PLATELET." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644528.
Full textAbstract:
Calmodulin (CaM)-binding proteins have been identified in human platelets using Western blotting techniques and 125I-CaM. Ten proteins of 245, 225. 175, 150, 90. 82(2), 60 and 41(2) kilodaltons (kDa) bind 125I-CaM in a Ca2+-dependent manner; the binding is blocked by both trifluoperazine and nonradiolabeled CaM. The 225 and 90 kDa proteins are labeled by antisera against myosin light chain kinase (MLCK); the 60 kDa and one of the 82 kDa proteins have been identified as the CaM-dependent phosphatase (calcineurin) and caldesmon. The other proteins are presumed to be other Ca2+/CaM regulated enzymes and proteins which may be important in platelet function. Most of the CaM-binding proteins are degraded upon addition of Ca2+ to a platelet homogenate; the degradation may be blocked by either EGTA, leupeptin or N-ethylmaleimide which suggests that the degradation is due to a Ca2+-dependent protease. Activation of intact platelets under conditions which promote platelet aggregation (i.e. stirring with extracellular Ca2+) also results in limited proteolysis of CaM-binding proteins including those labeled with anti sera against MLCK and the phosphatase. In vitro studies utilizing purified phosphatase and calpain I indicate that the phosphatase is irreversibly activated upon Ca2+-dependent proteolysis. The proteolytically-activated enzyme is insensitive to either Ca2+ or Ca2+/CaM; in addition, its activity in the absence of Ca2+ is even greater than the activity of the unproteolyzed enzyme in the presence of Ca2+ and CaM. Proteolytic stimulation of the phosphatase is accompanied by degradation of the 60 kDa subunit of the enzyme (subunit A) to 56, 52 and 45 kDa fragments, sequentially; proteolysis results in the loss of CaM binding to the enzyme. These results suggest that the Ca2+-dependent protease may have a physiological role in platelet activation as an irreversible activator of Ca2+/ CaM-dependent reactions. Supported by NIH grant HL29766.
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Ishiguro, H., S. Higashiyama, C. Namikawa, I. Ohkubo, and M. Sasaki. "MAPPING OF FUNCTIONAL DOMAINS OF HUMAN HIGH MOLECULAR WEIGHT (HMW) AND LOW MOLECULAR WEIGHT (LMW) KININOGENS BY USING MURINE MONOCLONAL ANTIBODIES (MAbs)." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642849.
Full textAbstract:
It has been widely known that HMW and LMW kininogens are the large potential sources of kinin in human blood, and that HMW kininogen also functions as a cofactor in the contact activation of blood coagulation. Recently, it has been demonstrated that the heavy chains of kininogens strongly inhibited a number of cysteine proteinases such as calpains, cathepsins, papain and ficin. We made an attempt at mapping of functional domains on the molecules of both kininogens by using MAbs.Thirty four MAbs raised against human HMW and LMW kininogens were screened by ELISA. By using HMW kininogen, kinin-free HMW kininogen, kinin and fragment 1.2 (fr 1.2)-free HMW kininogen, LMW kininogen, kinin-free LMW kininogen, heavy chain of LMW kininogen and light chains of both kininogens, the MAbs were characterized and.classified into four groups; [1] 20 MAbs reacted with heavy chain, a common region of HMW and LMW kininogens. These MAbs possessed the specificity for domain 1 (2 MAbs), domain 2 (2 MAbs), domain 3 (7 MAbs), and both domains 2 and 3 (7 MAbs) of the heavy chain; [2] 7 MAbs recognized the fr 1.2, a unique histidine-rich region; [3] 5 MAbs reacted with the light chain of HMW kininogen; [4] 2 MAbs recognized the light chain of LMW kininogen.Two MAbs, designated HKG H7 and H12, effectively inhibited the cysteine proteinase inhibitor activity of HMW and LMW kininogens and the others did not affect it. Further, the MAbs, which recognized the fr 1.2 or light chain of HMW kininogen, suppressed the clotting activity. Especially, 2 MAbs, named HKG L2 and L5, effectively suppressed the clotting activity of HMW kininogen. The former, which neutralized about 70% of the clotting activity, reacted specifically with fr 1.2 region of HMW kininogen, and the latter, which neutralized more than 90% of it, recognized the light chain of HMW kininogen. In the results of competition ELISA, fr 1.2 specific MAbs could be classified into 5 kinds of MAbs for recognition sites, and the light chain (HMW kininogen)-specific MAbs also could be classified into 3 kinds of MAbs. Further, 2 light chain (LMW kininogen)-specific MAbs were thought to recognize an identical antigenic site.
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Lavenne-Pardonge, E., C. Col-De Beys, R. Dion, R. Ponlot, and M. Moriau. "EFFECT OF ANTIAGGREGANT ON OCCLUSION OF SAPHENOUS GRAFT CORONARY BYPASS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644823.
Full textAbstract:
Double blind study on 49 patients, 24receiving aspirine-dipyri-damole, 25 a placebo. In both groups 20 patients were followed during one year. The two groupsdid not differ according to age, sex and number of coronary bypass. In all the patients, Calparin (3 x 5000 U/day) was injected subcutanously the day before andthe 7 days after surgery. In the first group dipyridamole (25 mg/ kg) was injected during the same period. The second group received a placebo IV injection. Thereafter long acting dipyridamole (400 mg/day) and aspirin (200 mg/day) were given orally in the first group, placebo in the second one. Cardiac follow-up included E.C.G. and thallium at maximum exercise. Coronarography was performed only incase of reappearence of chest pain. No difference was found between the two groups for the coagulation parameters duringthe whole year of study. Statistically significant differences between the two groups were found during the same period for β-thromboglobulin, fibrino-peptide A and the ratio Δ+ βTG/Δ+ FPA. Plateletactivity, elevated in the placebo group, was kept in normal limits in the treated group. During the two first months for the placebo and during the first month for the treated group the ratio Δ+ βTG/Δ+ FPA decreased in all patients showing the importance at this time of plasmatic hypercoagulability compared to platelet hyperactivity. During the 12 months of the study 5 thrombotic accidents (25 %) were noted in the placebo group (2 myocardial infarctions, 2 occlusions of bypass, 1 case of cerebral arterial disease) and 2 (10 % in the treated group) (1 postoperative death, 1 myocardial infarction) (NS ; p =0,21). Our results lead to two conclusions : 1) Platelet antiaggregants may influencethe permeability of saphenous .graft coronary bypass. A careful study of platelet acti-r vity with eventual change of the drug used may improve the late resultsof surgery. 2) Association of anticoagulant therapy (anti-vitamin K) during the two first months after surgery could also be useful.