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Myelin recovery in multiple sclerosis: the challenge of remyelination. Brain Sci 2013; 3:1282-324. [PMID: 24961530 PMCID: PMC4061877 DOI: 10.3390/brainsci3031282] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/12/2013] [Accepted: 08/12/2013] [Indexed: 12/26/2022] Open
Abstract
Multiple sclerosis (MS) is the most common demyelinating and an autoimmune disease of the central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. T cell subsets (Th1, Th2, Th17, CD8+, NKT, CD4+CD25+ T regulatory cells) and B cells are involved in this disorder, thus new MS therapies seek damage prevention by resetting multiple components of the immune system. The currently approved therapies are immunoregulatory and reduce the number and rate of lesion formation but are only partially effective. This review summarizes current understanding of the processes at issue: myelination, demyelination and remyelination—with emphasis upon myelin composition/architecture and oligodendrocyte maturation and differentiation. The translational options target oligodendrocyte protection and myelin repair in animal models and assess their relevance in human. Remyelination may be enhanced by signals that promote myelin formation and repair. The crucial question of why remyelination fails is approached is several ways by examining the role in remyelination of available MS medications and avenues being actively pursued to promote remyelination including: (i) cytokine-based immune-intervention (targeting calpain inhibition), (ii) antigen-based immunomodulation (targeting glycolipid-reactive iNKT cells and sphingoid mediated inflammation) and (iii) recombinant monoclonal antibodies-induced remyelination.
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Nozaki K, Das A, Ray SK, Banik NL. Calpeptin attenuated apoptosis and intracellular inflammatory changes in muscle cells. J Neurosci Res 2011; 89:536-43. [PMID: 21290412 DOI: 10.1002/jnr.22585] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 11/22/2010] [Accepted: 11/22/2010] [Indexed: 12/24/2022]
Abstract
In idiopathic inflammatory myopathies (IIMs), extracellular inflammatory stimulation is considered to induce secondary intracellular inflammatory changes including expression of major histocompatibility complex class-I (MHC-I) and to produce a self-sustaining loop of inflammation. We hypothesize that activation of calpain, a Ca(2+) -sensitive protease, bridges between these extracellular inflammatory stress and intracellular secondary inflammatory changes in muscle cells. In this study, we demonstrated that treatment of rat L6 myoblast cells with interferon-γ (IFN-γ) caused expression of MHC-I and inflammation-related transcription factors (phosphorylated-extracellular signal-regulated kinase 1/2 and nuclear factor-κB). We also demonstrated that treatment with tumor necrosis factor-α (TNF-α) induced apoptotic changes and activation of calpain and cyclooxygenase-2. Furthermore, we found that posttreatment with calpeptin attenuated the intracellular changes induced by IFN-γ or TNF-α. Our results indicate that calpain inhibition attenuates apoptosis and secondary inflammatory changes induced by extracellular inflammatory stimulation in the muscle cells. These results suggest calpain as a potential therapeutic target for treatment of IIMs.
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Affiliation(s)
- Kenkichi Nozaki
- Division of Neurology, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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3
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Calpain inhibition attenuates intracellular changes in muscle cells in response to extracellular inflammatory stimulation. Exp Neurol 2010; 225:430-5. [PMID: 20673830 DOI: 10.1016/j.expneurol.2010.07.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/20/2010] [Accepted: 07/22/2010] [Indexed: 01/27/2023]
Abstract
Idiopathic inflammatory myopathies (IIMs), comprising of polymyositis, dermatomyositis, and inclusion-body myositis, are characterized by muscle weakness and various types of inflammatory changes in muscle cells. They also show non-inflammatory changes, including perifascicular atrophy, mitochondrial changes, and amyloid protein accumulation. It is possible that some molecules/mechanisms bridge the extracellular inflammatory stimulation and intracellular non-inflammatory changes. One such mechanism, Ca(2+) influx leading to calpain activation has been proposed. In this study, we demonstrated that post-treatment with calpeptin (calpain inhibitor) attenuated intracellular changes to prevent apoptosis (Wright staining) through both mitochondrial pathway (increase in Bax:Bcl-2 ratio) and endoplasmic reticulum stress pathway (activation of caspase-12), which were induced by interferon-gamma (IFN-γ) stimulation in rat L6 myoblast cells. Our results also showed that calpeptin treatment inhibited the expression of calpain, aspartyl protease cathepsin D, and amyloid precursor protein. Thus, our results indicate that calpain inhibition plays a pivotal role in attenuating muscle cell damage from inflammatory stimulation due to IFN-γ, and this may suggest calpain as a possible therapeutic target in IIMs.
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4
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Shao H, Chou J, Baty CJ, Burke NA, Watkins SC, Stolz DB, Wells A. Spatial localization of m-calpain to the plasma membrane by phosphoinositide biphosphate binding during epidermal growth factor receptor-mediated activation. Mol Cell Biol 2006; 26:5481-96. [PMID: 16809781 PMCID: PMC1592705 DOI: 10.1128/mcb.02243-05] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Calpain activity is required for de-adhesion of the cell body and rear to enable productive locomotion of adherent cells during wound repair and tumor invasion. Growth factors activate m-calpain (calpain 2, CAPN2) via ERK/mitogen-activated protein kinases, but only when these kinases are localized to the plasma membrane. We thus hypothesized that m-calpain is activated by epidermal growth factor (EGF) only when it is juxtaposed to the plasma membrane secondary to specific docking. Osmotic disruption of NR6 fibroblasts expressing the EGF receptor demonstrated m-calpain being complexed with the substratum-adherent membrane with this increasing in an EGF-dependent manner. m-Calpain colocalized with phosphoinositide biphosphate (PIP(2)) with exogenous phospholipase C removal of phosphoinositides, specifically, PI(4,5)P(2) but not PI(4)P(1) or PIP(3), releasing the bound m-calpain. Downregulation of phosphoinositide production by 1-butanol resulted in diminished PIP(2) in the plasma membrane and eliminated EGF-induced calpain activation. This PIP(2)-binding capacity resided in domain III of calpain, which presents a putative C2-like domain. This active conformation of this domain appears to be partially masked in the holoenzyme as both activation of m-calpain by phosphorylation at serine 50 and expression of constitutively active phosphorylation mimic glutamic acid-increased m-calpain binding to the membrane, consistent with blockade of this cascade diminishing membrane association. Importantly, we found that m-calpain was enriched toward the rear of locomoting cells, which was more pronounced in the plasma membrane footprints; EGF further enhanced this enrichment, in line with earlier reports of loss of PIP(2) in lamellipodia of motile cells. These data support a model of m-calpain binding to PIP(2) concurrent with and likely to enable ERK activation and provides a mechanism by which cell de-adhesion is directed to the cell body and tail as phospholipase C-gamma hydrolyzes PIP(2) in the protruding lamellipodia.
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Affiliation(s)
- Hanshuang Shao
- Department of Pathology, University of Pittsburgh, Scaife Hall, S-711, 3550 Terrace St., Pittsburgh, PA 15261, USA
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5
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Kolchinskaya LI, Malysheva MK. Activity of calpain in subcellular fractions of the rat brain. NEUROPHYSIOLOGY+ 2004. [DOI: 10.1007/s11062-005-0013-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Deregulation of cdk5, hyperphosphorylation, and cytoskeletal pathology in the Niemann-Pick type C murine model. J Neurosci 2002. [PMID: 12151531 DOI: 10.1523/jneurosci.22-15-06515.2002] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NPC-1 gene mutations cause Niemann-Pick type C (NPC), a neurodegenerative storage disease resulting in premature death in humans. Spontaneous mutation of the NPC-1 gene in mice generates a similar phenotype, usually with death ensuing by 12 weeks of age. Both human and murine NPC are characterized neuropathologically by ballooned neurons distended with lipid storage, axonal spheroid formation, demyelination, and widespread neuronal loss. To elucidate the biochemical mechanism underlying this neuropathology, we have investigated the phosphorylation of neuronal cytoskeletal proteins in the brains of npc-1 mice. A spectrum of antibodies against phosphorylated epitopes in neurofilaments (NFs) and MAP2 and tau were used in immunohistochemical and immunoblotting analyses of 4- to 12-week-old mice. Multiple sites in NFs, MAP2, and tau were hyperphosphorylated as early as 4 weeks of age and correlated with a significant increase in activity of the cyclin-dependent kinase 5 (cdk5) and accumulation of its more potent activator, p25, a proteolytic fragment of p35. At 5 weeks of age, the development of axonal spheroids was noted in the pons. p25 and cdk5 coaccumulated with hyperphosphorylated cytoskeletal proteins in axon spheroids. These various abnormalities escalated with each additional week of age, spreading to other regions of the brainstem, basal ganglia, cerebellum, and eventually, the cortex. Our data suggest that focal deregulation of cdk5/p25 in axons leads to cytoskeletal abnormalities and eventual neurodegeneration in NPC. The npc-1 mouse is a valuable in vivo model for determining how and when cdk5 becomes deregulated and whether cdk5 inhibitors would be useful in blocking NPC neurodegeneration.
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Hewitt KE, Lesiuk HJ, Tauskela JS, Morley P, Durkin JP. Selective coupling of mu-calpain activation with the NMDA receptor is independent of translocation and autolysis in primary cortical neurons. J Neurosci Res 1998; 54:223-32. [PMID: 9788281 DOI: 10.1002/(sici)1097-4547(19981015)54:2<223::aid-jnr10>3.0.co;2-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Excessive mu-calpain activation has been linked to several cellular pathologies including excitotoxicity and ischemia. In erythrocytes and other non-central nervous system (CNS) cells, calpain activation is thought to occur following a Ca2+-induced translocation of inactive cytosolic enzyme to membranes and subsequent autolysis. In the present report, we show that transiently exposing primary rat cortical neurons to lethal (50 microM) N-methyl-D-aspartic acid (NMDA) caused protracted calpain activation, measured as increased spectrin hydrolysis, but this was independent of translocation or autolysis of the protease. An anti-mu-calpain antibody showed that calpain was largely membrane associated in cortical neurons, and, consequently, neither translocation nor autolysis of the protease was observed following ionomycin or lethal NMDA treatment. By contrast, in rat erythrocytes, calpain was largely cytosolic and underwent rapid translocation and autolysis in response to ionomycin. Calpain-mediated spectrin hydrolysis was specifically coupled to Ca2+ entry through the NMDA receptor because nonspecific Ca2+ influx via ionomycin or KCl-mediated depolarization failed to activate the enzyme. Thus, calpain appears selectively linked to glutamate receptors in cortical neurons and regulated by mechanisms distinct from that occurring in many non-CNS cells. The data suggest that intracellular signals coupled to the NMDA receptor are responsible for activating calpain already associated with cellular membranes in cortical cells.
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Affiliation(s)
- K E Hewitt
- Cellular Neurobiology Group, Institute for Biological Sciences, National Research Council of Canada, University of Ottawa, Ontario
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8
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Prigge JT, Kirkpatrick-Keller DC, Killefer J. Isolation and characterization of a calpain activator in chicken skeletal muscle. Poult Sci 1998; 77:1411-6. [PMID: 9733131 DOI: 10.1093/ps/77.9.1411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The calpains (E.C. 3.4.22.17) and calpastatin constitute an ubiquitous, intracellular, Ca2+-dependent protease/inhibitor system. This system has been implicated as a principal regulator of myofibrillar protein degradation in both ante-mortem and postmortem muscle. Although proteolytic activity of the calpains is primarily controlled through interaction of calpain and calpastatin, evidence for an activator(s) has been limited and the reported characteristics varied. The function of the activator has not been elucidated. A putative calpain activator has been isolated from the Pectoralis muscle of broiler breeders (Cobb x Cobb). The activator elutes from an ion-exchange column at approximately 200 mM NaCl. Addition of activator increased apparent m-calpain activity to a level demonstrating a fourfold increase in proteolysis. The activator/calpain complex maintains a requirement for Ca2+ for proteolytic activity. Under physiological conditions, presence of the activator negates the ability of calpastatin to inhibit m-calpain. Additionally, the activator alone does not demonstrate proteolytic activity. Effect of the activator is pH-dependent; in a physiological pH range, the activator enhances m-calpain proteolytic activity but at pH less than 6.75 the effect is to inhibit m-calpain. The activator's ability to modulate m-calpain activity and eliminate calpastatin's effect provides a further means of regulating this important enzyme system.
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Affiliation(s)
- J T Prigge
- Division of Animal and Veterinary Sciences, West Virginia University, Morgantown 26506-6108, USA
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9
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Li HL, Feinstein SI, Liu L, Zimmerman UJ. An antisense oligodeoxyribonucleotide to m-calpain mRNA inhibits secretion from alveolar epithelial type II cells. Cell Signal 1998; 10:137-42. [PMID: 9481489 DOI: 10.1016/s0898-6568(97)00101-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We investigated the effect of translational suppression of m-calpain on [3H]-phosphatidylcholine (PC) secretion utilising an antisense oligodexoyribonucleotide (oligo) directed against mRNA encoding m-calpain catalytic subunit. Two types of oligo, sense (S) and antisense (AS), to a portion of exon 12 of rat m-calpain catalytic subunit mRNA were tested. Constitutive secretion was decreased by 23% by AS-oligo (1 microM) treatment, while S-oligo (1 microM) had no effect. TPA-stimulated secretion was inhibited about 50-60% by AS-oligo (1-3 microM) and the inhibition was concentration-dependent, while S-oligo (1 microM) only inhibited about 10% of TPA-stimulated secretion. Northern and Western blot analyses revealed that the AS-oligo treatment reduced m-calpain mRNA and protein levels by 32% and 78%, respectively. The data indicate that antisense strategy is effective in suppressing calpain expression and type II cell secretion.
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Affiliation(s)
- H L Li
- Institute for Environmental Medicine, University of Pennsylvania Medical Center, Philadelphia 19104, USA
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James T, Matzelle D, Bartus R, Hogan EL, Banik NL. New inhibitors of calpain prevent degradation of cytoskeletal and myelin proteins in spinal cord in vitro. J Neurosci Res 1998; 51:218-22. [PMID: 9469575 DOI: 10.1002/(sici)1097-4547(19980115)51:2<218::aid-jnr10>3.0.co;2-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We have determined the effects of the calpain inhibitors AK275 and AK295 upon purified m-calpain and calcium-mediated degradation of neurofilament protein (NFP) in rat spinal cord in vitro. After incubation, the soluble radioactivity and/or extent of myelin basic protein (MBP) or NFP degradation was determined. Fifty percent of caseinolytic activity was inhibited by both inhibitors at 0.6 microM concentration, while more than 90% inhibition was seen at 1.6 microM. In contrast, 37% and 64% inhibition of MBP degradation was seen with AK295 and AK275, respectively, at 10 microM concentration. The extent of NFP degradation in spinal cord was quantified from immunoblot enhanced chemiluminescence. The calcium-mediated breakdown of NFP was inhibited by both AK275 and AK295, and the inhibition was dose-dependent. A 50% inhibition of NFP degradation was seen with AK295 at 10 microM and was almost completely inhibited at 25-50 microM. AK295 was slightly more potent than AK275. These studies suggest that these potent calpain inhibitors may be used therapeutically to provide neuroprotection in vivo in experimental central nervous system trauma and ischemia.
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Affiliation(s)
- T James
- Department of Neurology, Medical University of South Carolina, Charleston 29425, USA
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Chakrabarti AK, Dasgupta S, Gadsden RH, Hogan EL, Banik NL. Regulation of brain m calpain Ca2+ sensitivity by mixtures of membrane lipids: activation at intracellular Ca2+ level. J Neurosci Res 1996; 44:374-80. [PMID: 8739157 DOI: 10.1002/(sici)1097-4547(19960515)44:4<374::aid-jnr9>3.0.co;2-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Combinations of certain phospholipids and gangliosides increase the specific activity of m calpain and can activate m calpain at 1 to 10 microM Ca2+ concentration. However, this level of calcium is still greater than the normal intracellular calcium level. We have used combinations of lipids to demonstrate the m calpain activity at the physiological Ca2+ level. GD1a (100 microM) and cerebroside (Cerb; 750 microM; 1:7.5) mixture was the most effective. At 0.5 microM to 1.0 microM Ca2+ concentrations, 15-20% of the maximal activity was detected for the purified myelin and cytosolic m calpains. Other combinations were GD1a (100 microM), GM1 (100 microM), Cerb (750 microM), sulfatide (Sulf; 750 microM), and phosphatidylinositol (PI; 300 microM) at a ratio of 1:1: 7.5:7.5:3, respectively. These lipid mixtures stimulated calpain activity at three- to tenfold less calcium concentration than control. The other mixtures, including GD1a:Sulf (1:9) > GD1a:PI (1:4) > PI:Sulf (1:5) > Cerb:Sulf (1:5) and PI:Cerb (1:2.5), also stimulated calpain activity at 1.0 microM Ca2+ concentration. Triton X-100, oxidized glutathione (GSSG), and calpain activator did not affect the Ca2+ requirement. Liposomes containing GD1a, Cerb, and m calpain also showed recognizable calpain activity at a significantly reduced Ca2+ concentration (0.4 microM), confirming the glycolipid-mediated enzyme modulation. These studies indicate that specific lipid mixtures can stimulate m calpain activity at an intracellular level of Ca2+.
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Affiliation(s)
- A K Chakrabarti
- Department of Neurology, Medical University of South Carolina, Charleston 29425, USA
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12
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Arthur JS, Crawford C. Investigation of the interaction of m-calpain with phospholipids: calpain-phospholipid interactions. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1293:201-6. [PMID: 8620030 DOI: 10.1016/0167-4838(95)00243-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Phosphatidyl inositol, phosphatidyl choline, phosphatidyl glycerol, phosphatidyl serine, phosphatidyl ethanolamine, phosphatidic acid and sphingomyelin were all found to be effective at reducing the Ca2+ requirement for m-calpain autolysis. In the absence of phospholipid, pig kidney m-calpain required 1.4 mM Ca2+ for 50% autolysis under the assay conditions used. Phospholipids caused a reduction in this Ca2+ requirement to a value between 0.45 mM Ca2+ for phosphatidyl glycerol and 1.1 mM Ca2+ for phosphatidyl ethanolamine. Previous studies (Crawford, C., Brown, N.R. and Willis, A.C. (1990) Biochem. J. 265, 575-579) have shown that the most probable site for phospholipid interaction in calpain is the N-terminal region between residues 39 to 62 of the small subunit of calpain (G17TAMRILGG). In this study we examine the possible role of this G17TAMRILGG region. Three synthetic peptides corresponding to parts of this sequence were used to examine the phospholipid binding sequence. Analysis of the phospholipid vesicle binding properties of these peptides suggested that both the TAMRIL and polyglycine sequences were required for binding to phosphatidyl inositol vesicles.
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Affiliation(s)
- J S Arthur
- Department of Biochemistry, University of Oxford, UK
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13
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Carillo S, Pariat M, Steff AM, Jariel-Encontre I, Poulat F, Berta P, Piechaczyk M. PEST motifs are not required for rapid calpain-mediated proteolysis of c-fos protein. Biochem J 1996; 313 ( Pt 1):245-51. [PMID: 8546691 PMCID: PMC1216890 DOI: 10.1042/bj3130245] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cytoplasmic degradation of c-fos protein is extremely rapid. Under certain conditions, it is a multi-step process initiated by calcium-dependent and ATP-independent proteases called calpains. PEST motifs are peptide regions rich in proline, glutamic acid/aspartic acid and serine/threonine residues, commonly assumed to constitute built-in signals for rapid recognition by intracellular proteases and particularly by calpains. Using a cell-free degradation assay and site-directed mutagenesis, we report here that the three PEST motifs of c-fos are not required for rapid cleavage by calpains. Testing the susceptibility of PEST motif-bearing and non-bearing transcription factors including GATA1, GATA3, Myo D, c-erbA, Tal-1 and Sry, demonstrates that PEST sequences are neither necessary nor sufficient for specifying degradation of other proteins by calpains. This conclusion is strengthened by the observation that certain proteins, reportedly known to be cleavable by calpains, are devoid of PEST motifs.
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Affiliation(s)
- S Carillo
- Institut de Génétique Moléculaire de Montpellier/UMR 9942, France
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14
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Nixon RA, Saito KI, Grynspan F, Griffin WR, Katayama S, Honda T, Mohan PS, Shea TB, Beermann M. Calcium-activated neutral proteinase (calpain) system in aging and Alzheimer's disease. Ann N Y Acad Sci 1994; 747:77-91. [PMID: 7847693 DOI: 10.1111/j.1749-6632.1994.tb44402.x] [Citation(s) in RCA: 207] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Calpains (CANPs) are a family of calcium-dependent cysteine proteases under complex cellular regulation. By making selective limited proteolytic cleavages, they activate or alter the regulation of certain enzymes, including key protein kinases and phosphatases, and induce specific cytoskeletal rearrangements, accounting for their suspected involvement in intracellular signaling, vesicular trafficking, and structural stabilization. Calpain activity has been implicated in various aging phenomena, including cataract formation and erythrocyte senescence. Abnormal activation of the large stores of latent calpain in neurons induces cell injury and is believed to underlie neurodegeneration in excitotoxicity, Wallerian degeneration, and certain other neuropathologic states involving abnormal calcium influx. In Alzheimer's disease, we found the ratio of activated calpain I to its latent precursor isoform in neocortex to be threefold higher than that in normal individuals and those with Huntington's or Parkinson's disease. Immunoreactivity toward calpastatin, the endogenous inhibitor of calpain, was also markedly reduced in layers II-V of the neocortex in Alzheimer's disease. The excessive calpain system activation suggested by these findings represents a potential molecular basis for synaptic loss and neuronal cell death in the brain in Alzheimer's disease given the known destructive actions of calpain I and its preferential neuronal and synaptic localization. In surviving cells, persistent calpain activation may also contribute to neurofibrillary pathology and abnormal amyloid precursor protein trafficking/processing through its known actions on protein kinases and the membrane skeleton. The degree of abnormal calpain activation in the brain in Alzheimer's disease strongly correlated with the extent of decline in levels of secreted amyloid precursor protein in brain. Cytoskeletal proteins that are normally good calpain substrates become relatively calpain resistant when they are hyperphosphorylated, which may contribute to their accumulation in neurofibrillary tangles. As a major effector of calcium signals, calpain activity may mirror disturbances in calcium homeostasis and mediate important pathologic consequences of such disturbances.
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Affiliation(s)
- R A Nixon
- Laboratories for Molecular Neuroscience, McLean Hospital, Belmont, Massachusetts 02178
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15
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Saito K, Elce JS, Hamos JE, Nixon RA. Widespread activation of calcium-activated neutral proteinase (calpain) in the brain in Alzheimer disease: a potential molecular basis for neuronal degeneration. Proc Natl Acad Sci U S A 1993; 90:2628-32. [PMID: 8464868 PMCID: PMC46148 DOI: 10.1073/pnas.90.7.2628] [Citation(s) in RCA: 446] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Calcium-activated neutral proteinases (CANPs or calpains) are believed to be key enzymes in intracellular signaling cascades and potential mediators of calcium-induced neuronal degeneration. To investigate their involvement in Alzheimer disease, we identified three isoforms of muCANP (calpain I) in human postmortem brain corresponding to an 80-kDa precursor and two autolytically activated isoforms (78 and 76 kDa). As an index of changes in the in vivo activity of muCANP in Alzheimer disease, the ratio of the 76-kDa activated isoform of muCANP to its 80-kDa precursor was measured by immunoassay in selected brain regions from 22 individuals with Alzheimer disease and 18 normal controls. This muCANP activation ratio was elevated 3-fold in the prefrontal cortex from patients with Alzheimer disease but not from patients with Huntington disease. The activation ratio was also significantly elevated, but to a lesser degree, in brain regions where Alzheimer pathology is milder and has not led to overt neuronal degeneration. These findings indicate that muCANP activation is not simply a consequence of cellular degeneration but may be associated with dysfunction in many neurons before gross structural changes occur. The known influences of CANPs on cytoskeleton and membrane dynamics imply that persistent CANP activation may contribute to neurofibrillary pathology and abnormal amyloid precursor protein processing prior to causing synapse loss or cell death in the most vulnerable neuronal populations. Pharmacological modulation of the CANP system may merit consideration as a potential therapeutic strategy in Alzheimer disease.
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Affiliation(s)
- K Saito
- McLean Hospital, Belmont, MA 02178
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16
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Banik NL, Chakrabarti AK, Hogan EL. Effects of detergents on Ca(2+)-activated neural proteinase activity (calpain) in neural and non-neural tissue: a comparative study. Neurochem Res 1992; 17:797-802. [PMID: 1641062 DOI: 10.1007/bf00969015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Calcium activated neutral proteinase (mcalpain) activity was determined in brain and other tissue of rat. More than 60% of the brain mcalpain activity was present in the particulate fraction while only 30% was in cytosol. In contrast, particulate fractions of liver, kidney, muscle, and heart contained about 8-12% of tissue mcalpain activity while 88% was present in cytosol. Removal of the endogenous inhibitor calpastatin increased the tissue mcalpain activity severalfold. Triton X-100 and deoxycholate (DOC) stimulated the neural calpain activity by ten-fold while activity in non-neural tissue was unaffected. Incubation with other detergents, e.g. Triton N-57 and thioglucopyranoside, stimulated brain calpain activity five-fold while Brij-35 did not have any effect. Sodiumdodecylsulphate (SDS), on the other hand, inhibited the enzyme activity. Brain contained the lowest calpain activity compared to non-neural tissue. The calpain activity in muscle, kidney and heart was three-fold greater than liver. Immunoblot identification of the enzyme revealed that calpain was predominantly in the particulate fraction and less in cytosol of brain while it was present mainly in cytosol and less in the pellet fractions of non-neural tissue.
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Affiliation(s)
- N L Banik
- Department of Neurology, Medical University of South Carolina, Charleston 29425
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17
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Banik NL, Chakrabarti AK, Konat GW, Gantt-Wilford G, Hogan EL. Calcium-activated neutral proteinase (calpain) activity in C6 cell line: compartmentation of mu and m calpain. J Neurosci Res 1992; 31:708-14. [PMID: 1315874 DOI: 10.1002/jnr.490310414] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Calcium-activated neutral proteinase (calpain) activity was determined, including in cytosol and membrane fractions, in rat glioma C6 cell line. The mu and m forms of calpain were separated by DEAE and phenylsepharose column chromatography and with removal of the endogenous inhibitor calpastatin. C6 cells contained more mcalpain than the mu isoform. More than 70% of mcalpain activity was membrane-associated and 20% was cytosolic. Isolated plasma membrane also contained 69% of the mcalpain activity. In contrast, approximately 80% of mucalpain activity was cytosolic and 16% was membranous. Half-maximal activity for mu and mcalpain was obtained at 1 microM and 0.2 mM CaCl2, respectively. Trypsin dissociation of cells reduced activity. Triton X-100 stimulated mcalpain activity of the whole homogenate and the membrane pellet but not of the cytosol. Activity of the myelin marker enzyme adenosine 2'3'-cyclic nucleotide 3'-phosphohydrolase (CNPase), was also found in C6 cells. The identification of calpain and CNPase in C6 cells is in keeping with an interpretation that C6 differentiation resembles, at least in part, that of the myelin-forming oligodendroglial cells.
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Affiliation(s)
- N L Banik
- Department of Neurology, Medical University of South Carolina, Charleston 29425
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Kamakura K, Ishiura S, Imajoh S, Nagata N, Sugita H. Distribution of calcium-activated neutral protease inhibitor in the central nervous system of the rat. J Neurosci Res 1992; 31:543-8. [PMID: 1640505 DOI: 10.1002/jnr.490310318] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ubiquitous existence of calcium-activated neutral protease (CANP, calpain), an enzyme whose activity is regulated by calcium ions and a specific endogenous CANP inhibitor (calpastatin), is well known. Although there has been much investigation concerning the distribution and role of CANP, investigations of the distribution of the CANP inhibitor using immunohistochemical techniques are rare. We made antiserum against a 40K fragment of cDNA corresponding to two C-terminal repeats of rat liver CANP inhibitor expressed in Escherichia coli. Using this antiserum, we examined the distribution of CANP inhibitor in the rat central nervous system by the ABC technique and compared it with the distribution of CANP. Neurons and glias were stained, with the cytosol stained diffusely and the cell membranes stained clearly and strongly. Axons and myelin were stained faintly, but nuclei and vessels were not stained. The distribution of CANP inhibitor was thus found to be similar to that of CANP.
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Affiliation(s)
- K Kamakura
- Third Department of Internal Medicine, National Defence Medical College, Saitama, Japan
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Díaz RS, Monreal J, Regueiro P, Lucas M. Preparation of a protein-free total brain white matter lipid fraction: characterization of liposomes. J Neurosci Res 1992; 31:136-45. [PMID: 1377282 DOI: 10.1002/jnr.490310119] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A method of preparing a total lipid extract (TLE), free of protein, by extracting brain white matter with tetrahydrofuran is presented. The optimal conditions of extraction were found to be 50 ml of THF per gram of lyophilized tissue, though fresh tissue can also be used if larger volumes of solvent are employed. The method allowed, in a short time and in a single step, a yield of TLE of 50% on a dry weight basis. Its analytical characterization revealed a qualitative and quantitative composition very similar to the lipid composition of CNS myelin, including all the phospholipid and galactolipid species, cholesterol and gangliosides, but it contained only traces (0.1%) of protein. TLE has been used to prepare liposomes, either multilamellar (MLVs) or unilamellar (LUVs, SUVs), characterized by freeze-fracture electron microscopy. A multilayered, heterogeneous population of liposomes is observed in the MLVs preparation. When these samples were submitted to a freezing and thawing procedure the resulting liposomes were single-walled, and their intravesicular volume was increased. They were quite impermeable to the monovalent cation 86Rb+ and, by contrast, rather permeable to 45Ca+ +. Their complex lipid composition, together with their permeability properties and their response to ionophores, make them very useful to study protein-lipid interactions occurring within the myelin membrane as well as the functional properties of myelin proteins in reconstitution experiments.
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Affiliation(s)
- R S Díaz
- Cajal Institute, C.S.I.C., Madrid, Spain
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