Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.68 (tissue plasminogen activator)
 11,311 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A full-length cDNA clone of a previously unidentified serine protease, myelencephalon-specific protease (MSP), has been isolated by using a PCR cloning strategy and has been shown to be expressed in a nervous system and spinal cord-specific pattern. Sequence analysis demonstrated that MSP is most similar in sequence to neuropsin, trypsin, and tissue kallikrein and is predicted to have trypsin-like substrate specificity. MSP mRNA was found to be approximately 10-fold greater in the CNS of the rat and human, as compared with most peripheral tissues, and within the CNS was found to be highest by a factor of four in the medulla oblongata and spinal cord. Levels of mRNA encoding tissue plasminogen activator (tPA) also were elevated in the spinal cord but were more widespread in peripheral tissues as compared with MSP. In the adult rat lumbosacral spinal cord, in situ localization of MSP mRNA demonstrated 2-fold higher levels in the white, as compared with the gray, matter. MSP mRNA expression was shown to increase 3-fold in the white matter and 1.5-fold in the gray laminae at 72 hr after intraperitoneal injection of the AMPA/kainate glutamate receptor-specific agonist, kainic acid (KA). MSP mRNA remained elevated in the ventral gray matter, including expression associated with the motor neurons of lamina IX, at 7 d after the initial excitotoxic insult. Together, these observations indicate that MSP is in a position to play a fundamental role in normal homeostasis and in the response of the spinal cord to injury.
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PMID:Nervous system-specific expression of a novel serine protease: regulation in the adult rat spinal cord by excitotoxic injury. 933 91

We evaluated the effects of oxidative stress in mouse brain induced by the intraperitoneal injection of diethyldithiocarbamate (DDC) on gene expression of the novel serine protease, neuropsin, and on shock-avoidance learning. The level of neuropsin mRNA in the hippocampal pyramidal neurons increased at 2 h after DDC treatment and decreased thereafter. At 7 days neuropsin mRNA significantly decreased to 60% of the pretreated control level and then returned to the control level at 30 days. Genes for tissue plasminogen activator, manganese superoxide dismutase, and heat shock protein did not differ in DDC-treated mice vs. the control group at 7 and 30 days. The shuttle-box avoidance learning was retarded at 7 days after DDC administration. However, it recovered to the control level at 30 days after DDC administration. The results suggest that generation of reactive oxygen species has an important role in neuropsin transcript in the limbic areas which might be related to the disturbance in avoidance learning.
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PMID:Effects of oxidative stress on the expression of limbic-specific protease neuropsin and avoidance learning in mice. 937 76

Serine proteases exert a variety of functions in the body; food digestion, regulation of other proteins and modification of extracellular matrix. Cumulative evidence has shown the importance of serine proteases in the nervous system as well. It has been shown that three serine proteases, thrombin, plasminogen activators and neuropsin, have functional roles in neural plasticity. Most of the actions of thrombin are thought to be mediated by its specific receptors. Thrombin reverses neurite outgrowth of serum-deprived neuroblastoma cells, and induces protective and apoptotic effects on neurons and glial cells depending on concentration and time. Tissue-type and urokinase-type plasminogen activators (tPA and uPA) distribute broadly in the brain. tPA and uPA exert a variety of functions during development. These proteases also function in long-term potentiation and kindling formation. Furthermore, tPA is essential to excitotoxic neuronal cell death. Neuropsin is a serine protease expressed in the limbic system of the brain. Kindling induced neuropsin mRNA and protein expression and anti-neuropsin antibody ameliorates kindling epilepsy. The possible roles of these proteases in neural plasticity are reviewed here.
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PMID:Plasticity-related serine proteases in the brain (review). 1008 14

Much attention has been paid to proteases involved in long-term potentiation (LTP). Calpains, Ca-dependent cysteine proteases, have first been demonstrated to be the mediator of LTP by the proteolytic cleavage of fodrin, which allows glutamate receptors located deep in the postsynaptic membrane to move to the surface. It is now generally considered that calpain activation is necessary for LTP formation in the cleavage of substrates such as protein kinase Czeta, NMDA receptors, and the glutamate receptor-interacting protein. Recent studies have shown that serine proteases such as tissue-type plasminogen activator (tPA), thrombin, and neuropsin are involved in LTP. tPA contributes to LTP by both receptor-mediated activation of cAMP-dependent protein kinase and the cleavage of NMDA receptors. Thrombin induces a proteolytic activation of PAR-1, resulting in activation of protein kinase C, which reduces the voltage-dependent Mg2+ blockade of NMDA receptor-channels. On the other hand, neuropsin may act as a regulatory molecule in LTP via its proteolytic degradation of extracellular matrix protein such as fibronectin. In addition to such neuronal proteases, proteases secreted from microglia such as tPA may also contribute to LTP. The enzymatic activity of each protease is strictly regulated by endogenous inhibitors and other factors in the brain. Once activated, proteases can irreversibly cleave peptide bonds. After cleavage, some substrates are inactivated and others are activated to gain new functions. Therefore, the issue to identify substrates for each protease is very important to understand the molecular basis of LTP.
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PMID:Proteases involved in long-term potentiation. 1246 76

Serine proteases such as tissue plasminogen activator (tPA), thrombin and neuropsin influence hippocampal plasticity involved in learning and memory by facilitating both synaptic remodelling and long-term potentiation. Given our previous findings that trypsin and its receptor, protease-activated receptor-2 (PAR2), are both highly expressed in pyramidal neurons of the hippocampus and that activation of PAR2 attenuates 'pathogenic' plasticity related to epilepsy, we wished to determine the role for PAR2 in normal, non-pathological hippocampal plasticity related to learning and memory. In a strain of rat that show high basal levels of anxiety, the Genetic Absence Epilepsy Rats from Strasbourg (GAERS), peripheral administration of the PAR2 peptide agonist, SLIGRL (1.5 mg/kg s.c.), induced distinct deficits in experience-dependent learning both in the test-retest paradigm of the elevated-plus maze and in the Morris water maze. In separate, conscious rats with indwelling intra-cerebroventricular cannulae, SLIGRL rapidly appeared in cerebrospinal fluid (CSF) following peripheral administration and had a half-life in CSF of approximately 25 min. These results suggest that activation of central PAR2 with brain accessible peptide agonists causes a temporary deficit in the formation and/or recollection of experience-dependent learning and memory.
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PMID:A regulatory role for protease-activated receptor-2 in motivational learning in rats. 1941 9

Recent studies implicate extracellular proteases in synaptic plasticity, learning, and memory. The data are especially strong for such serine proteases as thrombin, tissue plasminogen activator, neurotrypsin, and neuropsin as well as matrix metalloproteinases, MMP-9 in particular. The role of those enzymes in the aforementioned phenomena is supported by the experimental results on the expression patterns (at the gene expression and protein and enzymatic activity levels) and functional studies, including knockout mice, specific inhibitors, etc. Counterintuitively, the studies have shown that the extracellular proteolysis is not responsible mainly for an overall degradation of the extracellular matrix (ECM) and loosening perisynaptic structures, but rather allows for releasing signaling molecules from the ECM, transsynaptic proteins, and latent form of growth factors. Notably, there are also indications implying those enzymes in the major neuropsychiatric disorders, probably by contributing to synaptic aberrations underlying such diseases as schizophrenia, bipolar, autism spectrum disorders, and drug addiction.
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PMID:Neural ECM proteases in learning and synaptic plasticity. 2541 Mar 56