calpain and Brain-Injuries--Traumatic

calpain has been researched along with Brain-Injuries--Traumatic* in 15 studies

Reviews

1 review(s) available for calpain and Brain-Injuries--Traumatic

ArticleYear
Calpain-2 Inhibitors as Therapy for Traumatic Brain Injury.
    Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 2023, Volume: 20, Issue:6

    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 plasticity and for learning some types of information and is neuroprotective. In contrast, calpain-2 activation limits the extent of synaptic plasticity and of learning and is neurodegenerative. These results have been validated with the use of calpain-1 knock-out mice and mice with a selective calpain-2 deletion in excitatory neurons of the forebrain. Through a medicinal chemistry campaign, we have identified a number of selective calpain-2 inhibitors and shown that these inhibitors do facilitate learning of certain tasks and are neuroprotective in a number of animal models of acute neurodegeneration. One of these inhibitors, NA-184, is currently being developed for the treatment of traumatic brain injury, and clinical trials are being planned.

    Topics: Animals; Brain; Brain Injuries, Traumatic; Calpain; Mice; Neuronal Plasticity; Neurons

2023

Other Studies

14 other study(ies) available for calpain and Brain-Injuries--Traumatic

ArticleYear
Characterization of Calpain and Caspase-6-Generated Glial Fibrillary Acidic Protein Breakdown Products Following Traumatic Brain Injury and Astroglial Cell Injury.
    International journal of molecular sciences, 2022, Aug-11, Volume: 23, Issue:16

    Glial fibrillary acidic protein (GFAP) is the major intermediate filament III protein of astroglia cells which is upregulated in traumatic brain injury (TBI). Here we reported that GFAP is truncated at both the C- and N-terminals by cytosolic protease calpain to GFAP breakdown products (GBDP) of 46-40K then 38K following pro-necrotic (A23187) and pro-apoptotic (staurosporine) challenges to primary cultured astroglia or neuron-glia mixed cells. In addition, with another pro-apoptotic challenge (EDTA) where caspases are activated but not calpain, GFAP was fragmented internally, generating a C-terminal GBDP of 20 kDa. Following controlled cortical impact in mice, GBDP of 46-40K and 38K were formed from day 3 to 28 post-injury. Purified GFAP protein treated with calpain-1 and -2 generates (i) major N-terminal cleavage sites at A-56*A-61 and (ii) major C-terminal cleavage sites at T-383*Q-388, producing a limit fragment of 38K. Caspase-6 treated GFAP was cleaved at D-78/R-79 and D-225/A-226, where GFAP was relatively resistant to caspase-3. We also derived a GBDP-38K N-terminal-specific antibody which only labels injured astroglia cell body in both cultured astroglia and mouse cortex and hippocampus after TBI. As a clinical translation, we observed that CSF samples collected from severe human TBI have elevated levels of GBDP-38K as well as two C-terminally released GFAP peptides (DGEVIKES and DGEVIKE). Thus, in addition to intact GFAP, both the GBDP-38K as well as unique GFAP released C-terminal proteolytic peptides species might have the potential in tracking brain injury progression.

    Topics: Animals; Astrocytes; Biomarkers; Brain Injuries; Brain Injuries, Traumatic; Calpain; Caspase 6; Glial Fibrillary Acidic Protein; Humans; Intermediate Filaments; Mice; Peptide Hydrolases; Peptides

2022
P13BP, a Calpain-2-Mediated Breakdown Product of PTPN13, Is a Novel Blood Biomarker for Traumatic Brain Injury.
    Journal of neurotrauma, 2021, 11-15, Volume: 38, Issue:22

    Biomarkers play an increasing role in medicinal biology. They are used for diagnosis, management, drug target identification, drug responses, and disease prognosis. We have discovered that calpain-1 and calpain-2 play opposite functions in neurodegeneration, with calpain-1 activation being neuroprotective, while prolonged calpain-2 activation is neurodegenerative. This notion has been validated in several mouse models of acute neuronal injury, in particular in mouse models of traumatic brain injury (TBI) and repeated concussions. We have identified a selective substrate of calpain-2, the tyrosine phosphatase, PTPN13, which is cleaved in brain after TBI. One of the fragments generated by calpain-2, referred to as P13BP, is also found in the blood after TBI both in mice and humans. In humans, P13BP blood levels are significantly correlated with the severity of TBI, as measured by Glasgow Coma Scale scores and loss of consciousness. The results indicate that P13BP represents a novel blood biomarker for TBI.

    Topics: Animals; Biomarkers; Brain Injuries, Traumatic; Calpain; Disease Models, Animal; Female; Glasgow Coma Scale; Humans; Male; Mice; Mice, Inbred C57BL; Protein Tyrosine Phosphatase, Non-Receptor Type 13; Rats; Rats, Sprague-Dawley

2021
Targeting the Extracellular Matrix in Traumatic Brain Injury Increases Signal Generation from an Activity-Based Nanosensor.
    ACS nano, 2021, 12-28, Volume: 15, Issue:12

    Topics: Brain; Brain Injuries; Brain Injuries, Traumatic; Calpain; Extracellular Matrix; Humans

2021
An Activity-Based Nanosensor for Traumatic Brain Injury.
    ACS sensors, 2020, 03-27, Volume: 5, Issue:3

    Currently, traumatic brain injury (TBI) is detected by medical imaging; however, medical imaging requires expensive capital equipment, is time- and resource-intensive, and is poor at predicting patient prognosis. To date, direct measurement of elevated protease activity has yet to be utilized to detect TBI. In this work, we engineered an activity-based nanosensor for TBI (TBI-ABN) that responds to increased protease activity initiated after brain injury. We establish that a calcium-sensitive protease, calpain-1, is active in the injured brain hours within injury. We then optimize the molecular weight of a nanoscale polymeric carrier to infiltrate into the injured brain tissue with minimal renal filtration. A calpain-1 substrate that generates a fluorescent signal upon cleavage was attached to this nanoscale polymeric carrier to generate an engineered TBI-ABN. When applied intravenously to a mouse model of TBI, our engineered sensor is observed to locally activate in the injured brain tissue. This TBI-ABN is the first demonstration of a sensor that responds to protease activity to detect TBI.

    Topics: Animals; Biosensing Techniques; Brain; Brain Injuries, Traumatic; Calpain; Female; Mice, Inbred C57BL; Nanoparticles; Polymers

2020
Calpain inhibitor MDL28170 improves the transplantation-mediated therapeutic effect of bone marrow-derived mesenchymal stem cells following traumatic brain injury.
    Stem cell research & therapy, 2019, 03-15, Volume: 10, Issue:1

    Studies have shown that transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) protects against brain damage. However, the low survival number of transplanted BMSCs remains a pertinent challenge and can be attributed to the unfavorable microenvironment of the injured brain. It is well known that calpain activation plays a critical role in traumatic brain injury (TBI)-mediated inflammation and cell death; previous studies showed that inhibiting calpain activation is neuroprotective after TBI. Thus, we investigated whether preconditioning with the calpain inhibitor, MDL28170, could enhance the survival of BMSCs transplanted at 24 h post TBI to improve neurological function.. TBI rat model was induced by the weight-drop method, using the gravitational forces of a free falling weight to produce a focal brain injury. MDL28170 was injected intracranially at the lesion site at 30 min post TBI, and the secretion levels of neuroinflammatory factors were assessed 24 h later. BMSCs labeled with green fluorescent protein (GFP) were locally administrated into the lesion site of TBI rat brains at 24 h post TBI. Immunofluorescence and histopathology were performed to evaluate the BMSC survival and the TBI lesion volume. Modified neurological severity scores were chosen to evaluate the functional recovery. The potential mechanisms by which MDL28170 is involved in the regulation of inflammation signaling pathway and cell apoptosis were determined by western blot and immunofluorescence staining.. Overall, we found that a single dose of MDL28170 at acute phase of TBI improved the microenvironment by inhibiting the inflammation, facilitated the survival of grafted GFP-BMSCs, and reduced the grafted cell apoptosis, leading to the reduction of lesion cavity. Furthermore, a significant neurological function improvement was observed when BMSCs were transplanted into a MDL28170-preconditioned TBI brains compared with the one without MDL28170-precondition group.. Taken together, our data suggest that MDL28170 improves BMSC transplantation microenvironment and enhances the neurological function restoration after TBI via increased survival rate of BMSCs. We suggest that the calpain inhibitor, MDL28170, could be pursued as a new combination therapeutic strategy to advance the effects of transplanted BMSCs in cell-based regenerative medicine.

    Topics: Allografts; Animals; Bone Marrow Cells; Brain Injuries, Traumatic; Calpain; Dipeptides; Disease Models, Animal; Graft Survival; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Rats; Rats, Sprague-Dawley

2019
Protection against TBI-Induced Neuronal Death with Post-Treatment with a Selective Calpain-2 Inhibitor in Mice.
    Journal of neurotrauma, 2018, 01-01, Volume: 35, Issue:1

    Traumatic Brain Injury (TBI) is a major cause of death and disability worldwide. The calcium-dependent protease, calpain, has been shown to be involved in TBI-induced neuronal death. However, whereas various calpain inhibitors have been tested in several animal models of TBI, there has not been any clinical trial testing the efficacy of calpain inhibitors in human TBI. One important reason for this could be the lack of knowledge regarding the differential functions of the two major calpain isoforms in the brain, calpain-1 and calpain-2. In this study, we used the controlled cortical impact (CCI) model in mice to test the roles of calpain-1 and calpain-2 in TBI-induced neuronal death. Immunohistochemistry (IHC) with calpain activity markers performed at different time-points after CCI in wild-type and calpain-1 knock-out (KO) mice showed that calpain-1 was activated early in cortical areas surrounding the impact, within 0-8 h after CCI, whereas calpain-2 activation was delayed and was predominant during 8-72 h after CCI. Calpain-1 KO enhanced cell death, whereas calpain-2 activity correlated with the extent of cell death, suggesting that calpain-1 activation suppresses and calpain-2 activation promotes cell death following TBI. Systemic injection(s) of a calpain-2 selective inhibitor, NA101, at 1 h or 4 h after CCI significantly reduced calpain-2 activity and cell death around the impact site, reduced the lesion volume, and promoted motor and learning function recovery after TBI. Our data indicate that calpain-1 activity is neuroprotective and calpain-2 activity is neurodegenerative after TBI, and that a selective calpain-2 inhibitor can reduce TBI-induced cell death.

    Topics: Animals; Apoptosis; Brain Injuries, Traumatic; Calpain; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neurons; Neuroprotective Agents; Oligopeptides; Recovery of Function

2018
Controlled cortical impact-induced neurodegeneration decreases after administration of the novel calpain-inhibitor Gabadur.
    Brain research bulletin, 2018, Volume: 142

    One aspect of secondary injury in traumatic brain injury is the marked increase in intracellular calcium and resultant over-activation of the calcium-dependent neutral cysteine protease calpain. Gabadur is a novel protease inhibitor with calpain-inhibition properties formulated from the classic protease inhibitor leupeptin linked to a pregabalin carrier. This construction allows the entire compound to cross the blood-brain barrier after peripheral administration to better target the site of injury. In this study, a single intraperitoneal dose of Gabadur was administered immediately following controlled cortical impact injury in rats. Neocortical slices were examined at 48 h post-injury via Fluoro-Jade B staining, revealing an improvement in cortical neurodegeneration in Gabadur treated rats. Levels of detrimental active calpain-2 measured via western blot were also decreased in rats receiving Gabadur. This data supports the benefit of targeted protease inhibition in the treatment of traumatic brain injury.

    Topics: Animals; Brain; Brain Injuries, Traumatic; Calpain; Disease Models, Animal; Glycoproteins; Leupeptins; Molecular Structure; Neurodegenerative Diseases; Neurons; Neuroprotective Agents; Pregabalin; Rats, Sprague-Dawley

2018
PrP
    Behavioural brain research, 2018, 03-15, Volume: 340

    The normal cellular prion protein (PrP

    Topics: Animals; Avoidance Learning; Brain; Brain Injuries, Traumatic; Calpain; Carbamates; Disease Models, Animal; Enzyme Inhibitors; Female; Head Injuries, Closed; Male; Mice, 129 Strain; Mice, Inbred C57BL; Mice, Transgenic; Neuroglia; Neurons; PrPC Proteins; Spatial Memory

2018
Protective Functions of PJ34, a Poly(ADP-ribose) Polymerase Inhibitor, Are Related to Down-Regulation of Calpain and Nuclear Factor-κB in a Mouse Model of Traumatic Brain Injury.
    World neurosurgery, 2017, Volume: 107

    Poly(ADP-ribose) polymerase (PARP), calpain, and nuclear factor-κB (NF-κB) are reported to participate in inflammatory reactions in pathologic conditions and are involved in traumatic brain injury. The objective of this study was to investigate whether PARP participates in inflammation related to calpain and NF-κB in a mouse model of controlled cortical impact (CCI).. PJ34 (10 mg/kg), a selective PARP inhibitor, was administered intraperitoneally 5 minutes and 8 hours after experimental CCI. We then performed a histopathologic analysis, and we measured calpain activity and protein levels in all animals. The cytosolic, mitochondria, and nuclear fractions were prepared and used to determine the levels of PARP, calpastatin, NF-κB p65, inhibitory-κB-α, tumor necrosis factor-α, interleukin-1β, intracellular adhesion molecule-1, inducible nitric oxide synthase, and cyclooxygenase-2. We then measured blood-brain barrier disruption using electron microscopy at 6 and 24 hours after CCI.. Treatment with PJ34 markedly reduced the extent of both cerebral contusion and edema, improved neurologic scores, and attenuated blood-brain barrier damage resulting from CCI. Our data showed that the cytosolic and nuclear fractions of calpain and NF-κB were up-regulated in the injured cortex and that these changes were reversed by PJ34. Moreover, PJ34 significantly enhanced the calpastatin and inhibitory-κB levels and decreased the levels of inflammatory mediators.. PARP inhibition by PJ34 suppresses the overactivation of calpain and the production of inflammatory factors that are caused by NF-κB activation and attenuates neuronal cell death in a mouse model of CCI.

    Topics: Animals; Brain Injuries, Traumatic; Calpain; Disease Models, Animal; Down-Regulation; Inflammation Mediators; Male; Mice; Mice, Inbred BALB C; Neuroprotective Agents; NF-kappa B; Phenanthrenes; Poly(ADP-ribose) Polymerase Inhibitors; Poly(ADP-ribose) Polymerases; Random Allocation

2017
The tyrosine phosphatase PTPN13/FAP-1 links calpain-2, TBI and tau tyrosine phosphorylation.
    Scientific reports, 2017, 09-18, Volume: 7, Issue:1

    Traumatic brain injury (TBI) increases the risk of Alzheimer's disease (AD). Calpain activation and tau hyperphosphorylation have been implicated in both TBI and AD. However, the link between calpain and tau phosphorylation has not been fully identified. We recently discovered that the two major calpain isoforms in the brain, calpain-1 and calpain-2, play opposite functions in synaptic plasticity and neuronal survival/death, which may be related to their different C-terminal PDZ binding motifs. Here, we identify the tyrosine phosphatase PTPN13 as a key PDZ binding partner of calpain-2. PTPN13 is cleaved by calpain-2, which inactivates its phosphatase activity and generates stable breakdown products (P13BPs). We also found that PTPN13 dephosphorylates and inhibits c-Abl. Following TBI, calpain-2 activation cleaved PTPN13, activated c-Abl and triggered tau tyrosine phosphorylation. The activation of this pathway was responsible for the accumulation of tau oligomers after TBI, as post-TBI injection of a calpain-2 selective inhibitor inhibited c-Abl activation and tau oligomer accumulation. Thus, the calpain-2-PTPN13-c-Abl pathway provides a direct link between calpain-2 activation and abnormal tau aggregation, which may promote tangle formation and accelerate the development of AD pathology after repeated concussions or TBI. This study suggests that P13BPs could be potential biomarkers to diagnose mTBI or AD.

    Topics: Animals; Brain Injuries, Traumatic; Calpain; Mice; Mice, Knockout; Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 13; tau Proteins; Tyrosine

2017
Protective Effects of Calpain Inhibition on Neurovascular Unit Injury through Downregulating Nuclear Factor-κB-related Inflammation during Traumatic Brain Injury in Mice.
    Chinese medical journal, 2017, 01-20, Volume: 130, Issue:2

    In addition to neurons, all components of the neurovascular unit (NVU), such as glial, endothelial, and basal membranes, are destroyed during traumatic brain injury (TBI). Previous studies have shown that excessive stimulation of calpain is crucial for cerebral injury after traumatic insult. The objective of this study was to investigate whether calpain activation participated in NVU disruption and edema formation in a mouse model of controlled cortical impact (CCI).. One hundred and eight mice were divided into three groups: the sham group, the control group, and the MDL28170 group. MDL28170 (20 mg/kg), an efficient calpain inhibitor, was administered intraperitoneally at 5 min, 3 h, and 6 h after experimental CCI. We then measured neurobehavioral deficits, calpain activity, inflammatory mediator levels, blood-brain barrier (BBB) disruption, and NVU deficits using electron microscopy and histopathological analysis at 6 h and 24 h after CCI.. The MDL28170 treatment significantly reduced the extent of both cerebral contusion (MDL28170 vs. vehicle group, 16.90 ± 1.01 mm΃ and 17.20 ± 1.17 mm΃ vs. 9.30 ± 1.05 mm΃ and 9.90 ± 1.17 mm΃, both P < 0.001) and edema (MDL28170 vs. vehicle group, 80.76 ± 1.25% and 82.00 ± 1.84% vs. 82.55 ± 1.32% and 83.64 ± 1.25%, both P < 0.05), improved neurological scores (MDL28170 vs. vehicle group, 7.50 ± 0.45 and 6.33 ± 0.38 vs. 12.33 ± 0.48 and 11.67 ± 0.48, both P < 0.001), and attenuated NVU damage resulting (including tight junction (TJ), basement membrane, BBB, and neuron) from CCI at 6 h and 24 h. Moreover, MDL28170 markedly downregulated nuclear factor-κB-related inflammation (tumor necrosis factor-α [TNF-α]: MDL28170 vs. vehicle group, 1.15 ± 0.07 and 1.62 ± 0.08 vs. 1.59 ± 0.10 and 2.18 ± 0.10, both P < 0.001; inducible nitric oxide synthase: MDL28170 vs. vehicle group, 4.51 ± 0.23 vs. 6.23 ± 0.12, P < 0.001 at 24 h; intracellular adhesion molecule-1: MDL28170 vs. vehicle group, 1.45 ± 0.13 vs. 1.70 ± 0.12, P < 0.01 at 24 h) and lessened both myeloperoxidase activity (MDL28170 vs. vehicle group, 0.016 ± 0.001 and 0.016 ± 0.001 vs. 0.024 ± 0.001 and 0.023 ± 0.001, P < 0.001 and 0.01, respectively) and matrix metalloproteinase-9 (MMP-9) levels (MDL28170 vs. vehicle group, 0.87 ± 0.13 and 1.10 ± 0.10 vs. 1.17 ± 0.13 and 1.25 ± 0.12, P < 0.001 and 0.05, respectively) at 6 h and 24 h after CCI.. These findings demonstrate that MDL28170 can protect the structure of the NVU by inhibiting the inflammatory cascade, reducing the expression of MMP-9, and supporting the integrity of TJ during acute TBI.

    Topics: Animals; Brain Injuries, Traumatic; Calpain; Dipeptides; Disease Models, Animal; Glycoproteins; Inflammation; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred BALB C; NF-kappa B; Peroxidase; Tumor Necrosis Factor-alpha

2017
Imaging and serum biomarkers reflecting the functional efficacy of extended erythropoietin treatment in rats following infantile traumatic brain injury.
    Journal of neurosurgery. Pediatrics, 2016, Volume: 17, Issue:6

    OBJECTIVE Traumatic brain injury (TBI) is a leading cause of death and severe morbidity for otherwise healthy full-term infants around the world. Currently, the primary treatment for infant TBI is supportive, as no targeted therapies exist to actively promote recovery. The developing infant brain, in particular, has a unique response to injury and the potential for repair, both of which vary with maturation. Targeted interventions and objective measures of therapeutic efficacy are needed in this special population. The authors hypothesized that MRI and serum biomarkers can be used to quantify outcomes following infantile TBI in a preclinical rat model and that the potential efficacy of the neuro-reparative agent erythropoietin (EPO) in promoting recovery can be tested using these biomarkers as surrogates for functional outcomes. METHODS With institutional approval, a controlled cortical impact (CCI) was delivered to postnatal Day (P)12 rats of both sexes (76 rats). On postinjury Day (PID)1, the 49 CCI rats designated for chronic studies were randomized to EPO (3000 U/kg/dose, CCI-EPO, 24 rats) or vehicle (CCI-veh, 25 rats) administered intraperitoneally on PID1-4, 6, and 8. Acute injury (PID3) was evaluated with an immunoassay of injured cortex and serum, and chronic injury (PID13-28) was evaluated with digitized gait analyses, MRI, and serum immunoassay. The CCI-veh and CCI-EPO rats were compared with shams (49 rats) primarily using 2-way ANOVA with Bonferroni post hoc correction. RESULTS Following CCI, there was 4.8% mortality and 55% of injured rats exhibited convulsions. Of the injured rats designated for chronic analyses, 8.1% developed leptomeningeal cyst-like lesions verified with MRI and were excluded from further study. On PID3, Western blot showed that EPO receptor expression was increased in the injured cortex (p = 0.008). These Western blots also showed elevated ipsilateral cortex calpain degradation products for αII-spectrin (αII-SDPs; p < 0.001), potassium chloride cotransporter 2 (KCC2-DPs; p = 0.037), and glial fibrillary acidic protein (GFAP-DPs; p = 0.002), as well as serum GFAP (serum GFAP-DPs; p = 0.001). In injured rats multiplex electrochemiluminescence analyses on PID3 revealed elevated serum tumor necrosis factor alpha (TNFα p = 0.01) and chemokine (CXC) ligand 1 (CXCL1). Chronically, that is, in PID13-16 CCI-veh rats, as compared with sham rats, gait deficits were demonstrated (p = 0.033) but then were reversed (p = 0.022) with EP

    Topics: Age Factors; Animals; Animals, Newborn; Biomarkers; Brain Injuries, Traumatic; Calpain; Cerebral Cortex; Cytokines; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Epoetin Alfa; Erythropoietin; Female; Gait Disorders, Neurologic; Gene Expression Regulation, Developmental; Glial Fibrillary Acidic Protein; Image Processing, Computer-Assisted; K Cl- Cotransporters; Male; Rats; Receptors, Erythropoietin; Statistics, Nonparametric; Symporters; Time Factors

2016
Involvement of aberrant cyclin-dependent kinase 5/p25 activity in experimental traumatic brain injury.
    Journal of neurochemistry, 2016, Volume: 138, Issue:2

    Traumatic brain injury (TBI) is associated with adverse effects on brain functions, including sensation, language, emotions and/or cognition. Therapies for improving outcomes following TBI are limited. A better understanding of the pathophysiological mechanisms of TBI may suggest novel treatment strategies to facilitate recovery and improve treatment outcome. Aberrant activation of cyclin-dependent kinase 5 (Cdk5) has been implicated in neuronal injury and neurodegeneration. Cdk5 is a neuronal protein kinase activated via interaction with its cofactor p35 that regulates numerous neuronal functions, including synaptic remodeling and cognition. However, conversion of p35 to p25 via Ca(2+) -dependent activation of calpain results in an aberrantly active Cdk5/p25 complex that is associated with neuronal damage and cell death. Here, we show that mice subjected to controlled cortical impact (CCI), a well-established experimental TBI model, exhibit increased p25 levels and consistently elevated Cdk5-dependent phosphorylation of microtubule-associated protein tau and retinoblastoma (Rb) protein in hippocampal lysates. Moreover, CCI-induced neuroinflammation as indicated by increased astrocytic activation and number of reactive microglia. Brain-wide conditional Cdk5 knockout mice (Cdk5 cKO) subjected to CCI exhibited significantly reduced edema, ventricular dilation, and injury area. Finally, neurophysiological recordings revealed that CCI attenuated excitatory post-synaptic potential field responses in the hippocampal CA3-CA1 pathway 24 h after injury. This neurophysiological deficit was attenuated in Cdk5 cKO mice. Thus, TBI induces increased levels of p25 generation and aberrant Cdk5 activity, which contributes to pathophysiological processes underlying TBI progression. Hence, selectively preventing aberrant Cdk5 activity may be an effective acute strategy to improve recovery from TBI. Traumatic brain injury (TBI) increases astrogliosis and microglial activation. Moreover, TBI deregulates Ca(2+) -homeostasis triggering p25 production. The protein kinase Cdk5 is aberrantly activated by p25 leading to phosphorylation of substrates including tau and Rb protein. Loss of Cdk5 attenuates TBI lesion size, indicating that Cdk5 is a critical player in TBI pathogenesis and thus may be a suitable therapeutic target for TBI.

    Topics: Animals; Brain; Brain Injuries, Traumatic; Calpain; Cyclin-Dependent Kinase 5; Disease Models, Animal; Male; Mice, Inbred C57BL; Nerve Tissue Proteins; Neurons; tau Proteins

2016
Attenuation of Blood-Brain Barrier Breakdown and Hyperpermeability by Calpain Inhibition.
    The Journal of biological chemistry, 2016, 12-30, Volume: 291, Issue:53

    Blood-brain barrier (BBB) breakdown and the associated microvascular hyperpermeability followed by brain edema are hallmark features of several brain pathologies, including traumatic brain injuries (TBI). Recent studies indicate that pro-inflammatory cytokine interleukin-1β (IL-1β) that is up-regulated following traumatic injuries also promotes BBB dysfunction and hyperpermeability, but the underlying mechanisms are not clearly known. The objective of this study was to determine the role of calpains in mediating BBB dysfunction and hyperpermeability and to test the effect of calpain inhibition on the BBB following traumatic insults to the brain. In these studies, rat brain microvascular endothelial cell monolayers exposed to calpain inhibitors (calpain inhibitor III and calpastatin) or transfected with calpain-1 siRNA demonstrated attenuation of IL-1β-induced monolayer hyperpermeability. Calpain inhibition led to protection against IL-1β-induced loss of zonula occludens-1 (ZO-1) at the tight junctions and alterations in F-actin cytoskeletal assembly. IL-1β treatment had no effect on ZO-1 gene (tjp1) or protein expression. Calpain inhibition via calpain inhibitor III and calpastatin decreased IL-1β-induced calpain activity significantly (p < 0.05). IL-1β had no detectable effect on intracellular calcium mobilization or endothelial cell viability. Furthermore, calpain inhibition preserved BBB integrity/permeability in a mouse controlled cortical impact model of TBI when studied using Evans blue assay and intravital microscopy. These studies demonstrate that calpain-1 acts as a mediator of IL-1β-induced loss of BBB integrity and permeability by altering tight junction integrity, promoting the displacement of ZO-1, and disorganization of cytoskeletal assembly. IL-1β-mediated alterations in permeability are neither due to the changes in ZO-1 expression nor cell viability. Calpain inhibition has beneficial effects against TBI-induced BBB hyperpermeability.

    Topics: Animals; Blood-Brain Barrier; Brain Injuries, Traumatic; Calpain; Cell Membrane Permeability; Cells, Cultured; Endothelium, Vascular; Glycoproteins; Interleukin-1beta; Mice; Mice, Inbred C57BL; Rats; RNA, Small Interfering

2016