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Protection of mature oligodendrocytes by inhibitors of caspases and calpains.

Mature mouse oligodendrocytes (OLs) are susceptible to death in demyelinating diseases such as multiple sclerosis and in brain injury following neurotrauma, ischemia, or stroke. To understand mechanisms leading to death of mature OLs and develop strategies for protection, we utilized cultures of mature mouse OLs to investigate the role of caspases and calpains in OL cell death mediated by different mechanisms. The agents used were (i) staurosporine, which induces apoptotic death via inhibition of protein kinases; (ii) kainate, which activates non-NMDA glutamate receptors; (iii) thapsigargin, w…

Calpains play a role in insulin secretion and action.

Studies of the genetic basis of type 2 diabetes suggest that variation in the calpain-10 gene affects susceptibility to this common disorder, raising the possibility that calpain-sensitive pathways may play a role in regulating insulin secretion and/or action. Calpains are ubiquitously expressed cysteine proteases that are thought to regulate a variety of normal cellular functions. Here, we report that short-term (4-h) exposure to the cell-permeable calpain inhibitors calpain inhibitor II and E-64-d increases the insulin secretory response to glucose in mouse pancreatic islets. This dose-depen…

Neurotoxicity induces cleavage of p35 to p25 by calpain.

Cyclin-dependent kinase 5 (cdk5) and its neuron-specific activator p35 are required for neurite outgrowth and cortical lamination. Proteolyt … esh brain lysates, addition of calcium can stimulate cleavage of p35 to p25. Specific inhibitors of calpain, a calcium-dependent cysteine protease, effectively inhibit the calcium-induced cleavage of p35. In vitro, calpain directly cleaves p35 to release a fragment with relative molecular mass 25,000. The sequence of the calpain cleavage product correspon …

Immunohistochemical localization of calpains and calpastatin in the rabbit eye.

The localization of the two Ca-activated extralysosomal proteases m-calpain and mu-calpain in the eye of the adult rabbit was examined by immunohistochemistry, using poly- and monoclonal antibodies against the corresponding rabbit antigens. Immunoreactivity against the two forms of calpains was observed in the epithelial cells on the external and internal surface of the cornea as well as in the epithelial cells covering the iris and ciliary body. The sclera and choroid layers showed a relatively weak immunoreactivity. Using anti m-calpain antibodies, the pigment epithelium in the retina was he…

[Calpain activation promotes dialysis-associated peritoneal fibrosis in rats].

OBJECTIVE: To explore the role of calpain activation in the progression of peritoneal fibrosis. OBJECTIVE: Twenty-four male Sprague-Dawley rats were randomized equally into control group, MDL28170 (a calpain inhibitor)+normal saline group, peritoneal dialysis (PD) model group and PD + MDL28170 group. In the latter two groups, the rats received daily intraperitoneal injections of 100 mL/kg of 4.25% glucose PD solution, and those in PD+MDL28170 group and MDL28170 saline group received daily infusion of 4 mg/kg MDL28170 every other day. Eight weeks later, the rats were euthanized for pathologica…

Mitochondrial dysfunction and consequences in calpain-3-deficient muscle.

BACKGROUND: Nonsense or loss-of-function mutations in the non-lysosomal cysteine protease calpain-3 result in limb-girdle muscular dystrophy type 2A (LGMD2A). While calpain-3 is implicated in muscle cell differentiation, sarcomere formation, and muscle cytoskeletal remodeling, the physiological basis for LGMD2A has remained elusive. METHODS: Cell growth, gene expression profiling, and mitochondrial content and function were analyzed using muscle and muscle cell cultures established from healthy and calpain-3-deficient mice. Calpain-3-deficient mice were also treated with PPAR-delta agonist (G…

Inhibition of angiotensin II and calpain attenuates pleural fibrosis.

Pleural fibrosis is associated with various inflammatory processes such as tuberculous pleurisy and bacterial empyema. There is currently no ideal therapeutic to attenuate pleural fibrosis. Some pro-fibrogenic mediators induce fibrosis through inflammatory processes, suggesting that blockage of these mediators might prevent pleural fibrosis. The MeT-5A human pleural mesothelial cell line (PMC) was used in this study as an in vitro model of fibrosis; and intra-pleural injection of bleomycin with carbon particles was used as an in vivo mouse model of pleural fibrosis. Calpain knockout mice, calp…

Targeting host calpain proteases decreases influenza A virus infection.

Influenza A viruses (IAV) trigger contagious acute respiratory diseases. A better understanding of the molecular mechanisms of IAV pathogenesis and host immune responses is required for the development of more efficient treatments of severe influenza. Calpains are intracellular proteases that participate in diverse cellular responses, including inflammation. Here, we used in vitro and in vivo approaches to investigate the role of calpain signaling in IAV pathogenesis. Calpain expression and activity were found altered in IAV-infected bronchial epithelial cells. With the use of small-interferin…

[Prokaryotic expression and function analysis of Schistosoma japonicum calpain].

OBJECTIVE: To clone and express recombinant calpain of Schistosoma japonicum (Sjcalpain), observe the distribution of Sjcalpain in S. japonicum cercariae and analyze its role in skin invasion. METHODS: The primers were designed according to the full-length sequence of calpain (GenBank accession No. AB016726). The genes encoding catalytic domain and Ca2+ binding domain of Sjcalpain were amplified by PCR, and the target fragments were subcloned into pET-28a. The recombinant proteins were expressed in E. coli BL21 (DE3) and purified by Ni-NTA resin. The rabbit polyclonal antibodies were prepared…

[Calpain plays a crucial role in TDP-43 pathology].

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease affecting healthy middle-aged individuals. Mislocali … which the ADAR2 gene is targeted in motor neurons. We found that Ca(2+)-dependent cysteine protease calpain cleaved TDP-43 into aggregation-prone fragments, which initiated TDP-43 mislocalization in the motor neurons expressing abnormally abundant Ca(2+)-permeable AMPA receptors. Here we summarized the molecular cascade leading to TDP-43 pathology observe …

Calpain inhibition mediates autophagy-dependent protection against polyglutamine toxicity.

Over recent years, accumulated evidence suggests that autophagy induction is protective in animal models of a number of neurodegenerative di … f neurodegenerative diseases. Here we evaluate the potential protective effect of downregulation of calpains. We demonstrate, in Drosophila, that calpain knockdown protects against the aggregation and toxicity of proteins, like mutant huntingtin, in an autophagy-dependent fashion. Furthermore, we demonstrate that, overexpression of the calpain inhibitor, …

Calpain-dependent cytoskeletal rearrangement exploited for anthrax toxin endocytosis.

The protective antigen component of Bacillus anthracis toxins can interact with at least three distinct proteins on the host cell surface, capillary morphogenesis gene 2 (CMG2), tumor endothelial marker 8, and β1-integrin, and, with the assistance of other host proteins, enters targeted cells by receptor-mediated endocytosis. Using an antisense-based phenotypic screen, we discovered the role of calpains in this process. We show that functions of a ubiquitous Ca(2+)-dependent cysteine protease, calpain-2, and of the calpain substrate talin-1 are exploited for association of anthrax toxin and it…

Tyrosine phosphorylation of WASP promotes calpain-mediated podosome disassembly.

Podosomes are actin-based adhesions involved in migration of cells that have to cross tissue boundaries such as myeloid cells. The Wiskott Aldrich Syndrome Protein regulates de novo actin polymerization during podosome formation and it is cleaved by the protease calpain during podosome disassembly. The mechanisms that may induce the Wiskott Aldrich Syndrome Protein cleavage by calpain remain undetermined. We now report that in myeloid cells, tyrosine phosphorylation of the Wiskott Aldrich Syndrome Protein-tyrosine291 (Human)/tyrosine293 (mouse) not only enhances Wiskott Aldrich Syndrome Protei…

Calpain-mediated MPP+ toxicity in mitochondrial DNA depleted cells.

MPP+ (1-methyl-4-phenylpyridium ion), a complex I - inhibiting metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), causes anatomic-specific neurodegeneration. To evaluate the broader role of mitochondria in MPP+-induced cell death, we exposed neuron-like NT2 human teratocarcinoma cells with mtDNA rho+ and without mtDNA (rho0) to MPP+. MPP+ minimized the ability of both rho+ and rho0 cells to reduce MTT. Only rho+ cells, though, initiated intrinsic pathway-mediated apoptosis. MPP+ also activated calpains in both rho+ and rho0 cell lines. The calpain inhibitor MDL 28710 was able t…

Calpain-mediated signaling mechanisms in neuronal injury and neurodegeneration.

Calpain is a ubiquitous calcium-sensitive protease that is essential for normal physiologic neuronal function. However, alterations in calcium homeostasis lead to persistent, pathologic activation of calpain in a number of neurodegenerative diseases. Pathologic activation of calpain results in the cleavage of a number of neuronal substrates that negatively affect neuronal structure and function, leading to inhibition of essential neuronal survival mechanisms. In this review, we examine the mechanistic underpinnings of calcium dysregulation resulting in calpain activation in the acute neurodege…

Calpain secreted by activated human lymphoid cells degrades myelin.

Calpain secreted by lymphoid (MOLT-3, M.R.) or monocytic (U-937, THP-1) cell lines activated with PMA and A23187 degraded myelin antigens. The degradative effect of enzymes released in the extracellular medium was tested on purified myelin basic protein and rat central nervous system myelin in vitro. The extent of protein degradation was determined by SDS-PAGE and densitometric analysis. Various proteinase inhibitors were used to determine to what extent protein degradation was mediated by calpain and/or other enzymes. Lysosomal and serine proteinase inhibitors inhibited 20-40% of the myelin-d…

Calpain-Dependent Protein Degradation Contributes to CASQ2-R33Q CPVT.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disease associated with cardiac arre … tially restored CASQ2 but not TRDN levels, suggesting distinct degradation mechanisms. In contrast, calpain inhibition restored CASQ2 and TRDN protein levels, decreased triggered activity in isolated cardiomyocytes, and reduced ventricular tachycardia episodes in vivo in Casq2R33Q/R33Q mice. Biochemical assays showed that TRDN is a direct calpain substrat …

Ингибиция Calpain-2 смягчает гиперкальцемию, вызванную несколькими миеломами.

Множественная миелома (ММ) — злокачественное гематологическое расстройство, характеризующееся неопластическим распространением плазменных клеток. Гиперкальцемия является распространенным осложнением в MM и часто считается вторичным последствием развития болезни. Когда уровень кальция сильно повышен, он может привести к коме у больных. Однако остается неясным, играет ли гиперкальцемия непосредственную роль в развитии ММ. Здесь мы обнаружили, что высокие концентрации кальция способствуют распространению клеток MM и связаны с кальпаином-2 (CAPN2). Мы также отметили, что выражение CAPN2 значительн

Совпадение в аннотации оригинала
Multiple myeloma (MM) is a malignant hematological disorder characterized by the neoplastic proliferation of plasma cells. Hypercalcemia is … we found that high calcium concentrations promote MM cell proliferation and it was associated with calpain-2 (CAPN2). We also observed that CAPN2 expression is significantly increased in MM patients and correlates with poor prognosis. Furthermore, knockdown of CAPN2 inhibited MM cell proliferation both in vitro and in vivo via upregulation of FN14 and in …

Calpain-2 Inhibitors as Therapy for Traumatic Brain Injury.

While calpains have long been implicated in neurodegeneration, no calpain inhibitor has been developed for the treatment of neurodegeneration. This is partly due to the lack of understanding of the specific functions of most of the 15 members of the calpain family. Work from our laboratory over the last 5-10 years has revealed that calpain-1 and calpain-2, two of the major calpain isoforms in the brain, play opposite roles in both synaptic plasticity/learning and memory and neuroprotection/neurodegeneration. Thus, calpain-1 activation is required for triggering certain forms of synaptic plasti…