Systemic LPS-induced neuroinflammation increases the susceptibility for proteasome inhibition-induced degeneration of the nigrostriatal pathway.

INTRODUCTION: Besides proteasome dysfunction, neuroinflammation is a common feature in the pathogenesis of Parkinson's disease (PD). Accordingly, peripheral inflammation has been shown to increase the susceptibility of the brain for nigrostriatal degeneration by inducing activation of glial cells and release of pro-inflammatory cytokines in the brain. Given that current animal models of PD fail to recapitulate the pathophysiology occurring in idiopathic PD, the aim of this study was to combine two pathogenic mechanisms (i.e. neuroinflammation and proteasome inhibition) to create a dual-hit mouse model of PD. METHODS: We repeatedly injected mice with a low dose of LPS (250 µg/kg/day i. p. for four days) to induce neuroinflammation, followed by a unilateral intranigral injection of lactacystin (LAC; 3 µg). Seven days later, mice were evaluated behaviorally to assess locomotion, anxiety- and depressive-like behavior. Nigrostriatal degeneration was analyzed by measuring striatal dopamine loss as well as loss of nigral dopaminergic neurons. Neuroinflammation was confirmed by quantifying microglial cells in the substantia nigra (SN) and cytokine expression in the striatum. RESULTS: Repeated systemic LPS injections increase the number of microglial cells in the SN and induce a mixed profile of pro- and anti-inflammatory cytokines in the striatum without affecting the integrity of the nigrostriatal pathway. Systemic LPS-induced neuroinflammation, however, increases the susceptibility of the nigrostriatal pathway for LAC-induced degeneration. CONCLUSION: Recapitulating two relevant etiopathogenic mechanisms of PD - neuroinflammation and proteasome inhibition-, we propose this dual-hit model as a relevant mouse model for PD that could be used to investigate potential therapeutic targets.

Stefin A-functionalized liposomes as a system for cathepsins S and L-targeted drug delivery.

Proteolytic activity in the tumor microenvironment is one of the key elements supporting tumor development and metastasis. One of the key families of proteases that are overexpressed in various types of cancer and implicated in different stages of tumor progression are cysteine cathepsins. Among them, cathepsins S and L can be secreted into the tumor microenvironment by tumor and/or immune cells, making them promising drug delivery targets. Here we present a new system for cathepsin S/L targeting using a liposomal drug carrier system functionalized with the endogenous cysteine cathepsin inhibitor, stefin A. The selective targeting of cathepsins by stefin A-conjugated liposomes was confirmed in vitro and in vivo, demonstrating the potential of this approach for cancer diagnosis and treatment.

Cathepsin B inhibition ameliorates the non-alcoholic steatohepatitis through suppressing caspase-1 activation.

Non-alcoholic fatty liver disease (NAFLD) has emerged as the most common chronic liver disease. NLRP3 inflammasome activation has been widely studied in the pathogenesis of NAFLD. Cathepsin B (CTSB) is a ubiquitous cysteine cathepsin, and the role of CTSB in the progression and development of NAFLD has received extensive concern. However, the exact roles of CTSB in the NAFLD development and NLRP3 inflammasome activation are yet to be evaluated. In the present study, we used methionine choline-deficient (MCD) diet to establish mice NASH model. CTSB inhibitor (CA-074) was used to suppress the expression of CSTB. Expressions of CTSB and caspase-1 were evaluated by immunohistochemical staining. Serum IL-1ß and IL-18 levels were also determined. Palmitic acid was used to stimulate Kupffer cells (KCs), and protein expressions of CTSB, NLRP3, ASC (apoptosis-associated speck-like protein containing CARD), and caspase-1 in KCs were detected. The levels of IL-1ß and IL-18 in the supernatant of KCs were evaluated by enzyme-linked immunosorbent assay (ELISA). Our results showed that CTSB inhibition improved the liver function and reduced hepatic inflammation and ballooning, and the levels of pro-inflammatory cytokines IL-1ß and IL-18 were decreased. The expressions of CTSB and caspase-1 in liver tissues were increased in the NASH group. In in vitro experiments, PA stimulation could increase the expressions of CTSB and NLRP3 inflammasome in KCs, and CTSB inhibition downregulated the expression of NLRP3 inflammasome in KCs, when challenged by PA. Moreover, CTSB inhibition effectively suppressed the expression and activity of caspase-1 and subsequently secretions of IL-1ß and IL-18. Collectively, these results suggest that CTSB inhibition limits NLRP3 inflammasome-dependent NASH formation through regulating the expression and activity of caspase-1, thus providing a novel anti-inflammatory signal pathway for the therapy of NAFLD.

Nonclinical and clinical pharmacological characterization of the potent and selective cathepsin K inhibitor MIV-711.

BACKGROUND: Cathepsin K is an attractive therapeutic target for diseases in which bone resorption is excessive such as osteoporosis and osteoarthritis (OA). The current paper characterized the pharmacological profile of the potent and selective cathepsin K inhibitor, MIV-711, in vitro and in cynomolgus monkeys, and assessed translation to human based on a single dose clinical study in man. METHODS: The potency and selectivity of MIV-711 were assessed in vitro using recombinant enzyme assays and differentiated human osteoclasts. MIV-711 was administered to healthy cynomolgus monkeys (3-30 µmol/kg, p.o.). Plasma levels of MIV-711 and the bone resorption biomarker CTX-I were measured after single dose experiments, and urine levels of CTX-I, NTX-I and CTX-II biomarkers were measured after repeat dose experiments. The safety, pharmacokinetics and pharmacodynamics (serum CTX-I) of MIV-711 were assessed in human healthy subjects after single ascending doses from 20 to 600 mg. RESULTS: MIV-711 was a potent inhibitor of human cathepsin K (Ki: 0.98 nmol/L) with > 1300-fold selectivity towards other human cathepsins. MIV-711 inhibited human osteoclast-mediated bone resorption with an IC50 value of 43 nmol/L. Single oral doses of MIV-711 to monkeys reduced plasma levels of CTX-I in a dose-dependent fashion by up to 57% at trough. The effect on CTX-I was linearly correlated to the plasma exposure of MIV-711, while the efficacy duration outlasted plasma exposure. Repeat oral dosing with MIV-711 also reduced urinary levels of the bone resorption biomarkers CTX-I (by 93%) and NTX-I (by 71%) and the cartilage degradation biomarker CTX-II (by 71%). MIV-711 was safe and well-tolerated when given as single ascending doses to healthy subjects. MIV-711 reduced serum CTX-I levels in a dose-dependent manner by up to 79% at trough. The relationship between MIV-711 exposure and effects on these biomarkers in humans was virtually identical when compared to the corresponding monkey data. CONCLUSIONS: MIV-711 is a potent and selective cathepsin K inhibitor with dose-dependent effects on biomarkers of bone and cartilage degradation in monkey and human. Taken together, MIV-711 shows promise for the treatment of bone and cartilage related disorders in humans, such as OA. Trial Registration EudraCT number 2011-003024-12, registered on June 22nd 2011.

Dipeptidyl Peptidase 1 Inhibitor AZD7986 Induces a Sustained, Exposure-Dependent Reduction in Neutrophil Elastase Activity in Healthy Subjects.

Neutrophil serine proteases (NSPs), such as neutrophil elastase (NE), are activated by dipeptidyl peptidase 1 (DPP1) during neutrophil maturation. High NSP levels can be detrimental, particularly in lung tissue, and inhibition of NSPs is therefore an interesting therapeutic opportunity in multiple lung diseases, including chronic obstructive pulmonary disease (COPD) and bronchiectasis. We conducted a randomized, placebo-controlled, first-in-human study to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple oral doses of the DPP1 inhibitor AZD7986 in healthy subjects. Pharmacokinetic and pharmacodynamic data were analyzed using nonlinear mixed effects modeling and showed that AZD7986 inhibits whole blood NE activity in an exposure-dependent, indirect manner-consistent with in vitro and preclinical predictions. Several dose-dependent, possibly DPP1-related, nonserious skin findings were observed, but these were not considered to prevent further clinical development. Overall, the study results provided confidence to progress AZD7986 to phase II and supported selection of a clinically relevant dose.

Therapeutic effect of Schistosoma japonicum cystatin on bacterial sepsis in mice.

BACKGROUND: Sepsis is a life-threatening complication of an infection and remains one of the leading causes of mortality in surgical patients. Bacteremia induces excessive inflammatory responses that result in multiple organ damage. Chronic helminth infection and helminth-derived materials have been found to immunomodulate host immune system to reduce inflammation against some allergic or inflammatory diseases. Schistosoma japonicum cystatin (Sj-Cys) is a cysteine protease inhibitor that induces regulatory T-cells and a potential immunomodulatory. The effect of Sj-Cys on reducing sepsis inflammation and mortality was investigated. METHODS: Sepsis was induced in BALB/c mice using cecal ligation and puncture (CLP), followed by intraperitoneal injection of different doses (10, 25 or 50 µg) of recombinant Sj-Cys (rSj-Cys). The therapeutic effect of rSj-Cys on sepsis was evaluated by observing the survival rates of mice for 96 h after CLP and the pathological injury of liver, kidney and lung by measuring the levels of alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and creatinine (Cr) in sera and the tissue sections pathology, and the expression of MyD88 in liver, kidney and lung tissues. The immunological mechanism was investigated by examining pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß) and IL-10 and TGF-ß1 in mice sera and in culture of macrophages stimulated by lipopolysaccharides (LPS). RESULTS: rSj-Cys treatment provided significant therapeutic effects on CLP-induced sepsis in mice demonstrated with increased survival rates, alleviated overall disease severity and tissue injury of liver, kidney and lung. The rSj-Cys conferred therapeutic efficacy was associated with upregualted IL-10 and TGF-ß1 cytokines and reduced pro-inflammatory cytokines TNF-α, IL-6, IL-1ß. MyD88 expression in liver, kidney and lung tissues of rSj-Cys-treated mice was reduced. In vitro assay with macrophages also showed that rSj-Cys inhibited the release of pro-inflammatory cytokines and mediator nitric oxide (NO) after being stimulated by lipopolysaccharide (LPS). CONCLUSIONS: The results suggest the anti-inflammatory potential of rSj-Cys as a promising therapeutic agent on sepsis. The immunological mechanism underlying its therapeutic effect may involve the downregulation of pro-inflammatory cytokines and upregulation of IL-10 and TGF-ß1 cytokines possibly via downregulation of the TLR adaptor-transducer MyD88 pathway. The findings suggest rSj-Cys is a potential therapeutic agent for sepsis and other inflammatory diseases.

Zonisamide attenuates lactacystin-induced parkinsonism in mice without affecting system xc.

Zonisamide (ZNS), an anticonvulsant drug exhibiting symptomatic effects in Parkinson's disease (PD), was recently reported to exert neuroprotection in rodent models. One of the proposed neuroprotective mechanisms involves increased protein expression of xCT, the specific subunit of the cystine/glutamate antiporter system xc-, inducing glutathione (GSH) synthesis. Here, we investigated the outcome of ZNS treatment in a mouse model of PD based on intranigral proteasome inhibition, and whether the observed effects would be mediated by system xc-. The proteasome inhibitor lactacystin (LAC) was administered intranigrally to male C57BL/6J mice receiving repeated intraperitoneal injections of either ZNS 30mgkg-1 or vehicle. Drug administration was initiated three days prior to stereotaxic LAC injection and was maintained until six days post-surgery. One week after lesion, mice were behaviorally assessed and investigated in terms of nigrostriatal neurodegeneration and molecular changes at the level of the basal ganglia, including expression levels of xCT. ZNS reduced the loss of nigral dopaminergic neurons following LAC injection and the degree of sensorimotor impairment. ZNS failed, however, to modulate xCT expression in basal ganglia of lesioned mice. In a separate set of experiments, the impact of ZNS treatment on system xc- was investigated in control conditions in vivo as well as in vitro. Similarly, ZNS did not influence xCT or glutathione levels in naive male C57BL/6J mice, nor did it alter system xc- activity or glutathione content in vitro. Taken together, these results demonstrate that ZNS treatment provides neuroprotection and behavioral improvement in a PD mouse model based on proteasome inhibition via system xc- independent mechanisms.

Chronic cathepsin inhibition by E-64 in Dahl salt-sensitive rats.

Cysteine cathepsins are lysosomal enzymes expressed in the kidneys and other tissues, and are involved in the maturation and breakdown of cellular proteins. They have been shown to be integrally involved in the progression of many cardiovascular and renal diseases. The goal of this study was to determine the involvement of cysteine cathepsins in the development of salt-sensitive hypertension and associated kidney damage. In our experiments, Dahl salt-sensitive (SS) rats were fed an 8% high salt NaCl diet and intravenously infused with the irreversible cysteine cathepsin inhibitor E-64 (1 mg/day) or the vehicle (control). Both the control and E-64 infused groups developed significant hypertension and kidney damage, and no difference of the mean arterial pressure and the hypertension-associated albuminuria was observed between the groups. We next tested basal calcium levels in the podocytes of both control and infused groups using confocal calcium imaging. Basal calcium did not differ between the groups, indicative of the lack of a protective or aggravating influence by the cathepsin inhibition. The efficacy of E-64 was tested in Western blotting. Our findings corresponded to the previously reported, E-64 induced increase in cathepsin B and L abundance. We conclude that the inhibition of cysteine cathepsins by E-64 does not have any effects on the blood pressure development and kidney damage, at least under the studied conditions of this model of SS hypertension.

Novel cruzipain inhibitors for the chemotherapy of chronic Chagas disease.

Despite current efforts worldwide to develop new medications against Chagas disease, only two drugs are available, nifurtimox and benznidazole. Both drugs require prolonged treatment and have multiple side effects and limited efficacy on adult patients chronically infected with Trypanosoma cruzi. Recently, computer-guided drug repositioning led to the discovery of the trypanocidal effects of clofazimine and benidipine. These compounds showed inhibitory effects on cruzipain, the major cysteine protease of T. cruzi, of different parasite stages and in a murine model of acute Chagas disease. The aim of this work was to determine the efficacy of these novel cruzipain inhibitors when administered in a murine model of chronic Chagas disease. Benidipine and clofazimine were able to reduce the parasite burden in cardiac and skeletal muscles of chronically infected mice compared with untreated mice as well as diminish the inflammatory process in these tissues. Further studies should be performed to study the synergism with benznidazole and nifurtimox in view of combined therapies.

Proteasome Inhibitor MG132 Enhances Sensitivity to Cisplatin on Ovarian Carcinoma Cells In Vitro and In Vivo.

BACKGROUND: Platinum-based combination chemotherapy after surgery is considered a standard treatment; therefore, any recent drug development should be new, effective, and low toxic, and should have a synergistic effect with platinum. This study aimed to observe the growth of SKOV3 cells after treatment with cisplatin by combining with carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG132) and to investigate the effect of the relationship between MG132 and cisplatin combination. MATERIALS AND METHODS: Cell growth was detected by methyl thiazolyl tetrazolium assay after treatment with MG132 at 0.5, 1.5, 2.5, 3.5, and 5.0 µg/mL concentrations for 24, 48, and 72 hours; with cisplatin at 1.0, 2.0, 3.0, 4.0, and 5.0 µg/mL concentrations; and with combination with MG132 at 1.5 µg/mL for 24 hours. The apoptotic rates of cells were detected by a flow cytometer after cisplatin treatment at 1.0, 2.0, 3.0, and 4.0 µg/mL concentrations and that combined with MG132 at 1.5 µg/mL concentration for 12, 24, and 36 hours. A total of 20 BALB/c (nu/nu) female nude mice (age, 4-6 weeks; body weight, 17-19 g) were divided into 4 groups: control, MG132, cisplatin, and combination groups. The expression of Caspase3 and Beclin1 was detected by Western blot analysis and reverse transcription-polymerase chain reaction after treatment with 3.0 µg/mL of the cisplatin group and combined treatment with 1.5 µg/mL of MG132 group for 24 hours, respectively. RESULTS: Methyl thiazolyl tetrazolium assay demonstrated the inhibitory rates, and the flow cytometery showed that the apoptotic rates in the combination group were higher than those in the cisplatin group (P < 0.01). Western blot analysis and reverse transcription-polymerase chain reaction detected that Caspase3 and Beclin1 at a relative quantity in the combination group were higher than those in the cisplatin group (P < 0.05). CONCLUSIONS: MG132 has a synergistic antitumor effect by combining with cisplatin, and it is expected to be an effective antitumor drug for platinum-resistant refractory ovarian cancer.

Hemoglobin Degrading Proteases of Plasmodium falciparum as Antimalarial Drug Targets.

Plasmepsins, falcipains and aminopeptidases are Plasmodium falciparum proteases involved in human host hemoglobin degradation and other processes like erythrocyte invasion and rupture. Antimalarial drug resistance and natural selection in parasite are important reasons that create the urgent need of novel targets and lead compounds to overcome the burden of malaria. This report explored progress of the study covering proteases and their inhibitors specific to hemoglobin degradation. Additionally, in silico predicted antimalarial targets, balancing selection and drug-protein interaction are included.

Proteinase inhibitors: a promising drug class for treating leishmaniasis.

This review presents and discusses the current status and perspectives of leishmaniasis treatment, with a special focus on the use of proteinase inhibitors. The history of treatment development, the first- and second-choice modern drugs and the advantages and disadvantages of using proteinases inhibitors as leishmanicidal treatments are presented and discussed. The reports gathered herein confirm the potential usefulness of proteinases inhibitors as an alternative or complement to the current leishmaniasis treatments. They also support the hypothesis that a combined treatment with multiple proteinase inhibitors may be efficient against Leishmania infections in vertebrate hosts.

Specific calpain inhibition by calpastatin prevents tauopathy and neurodegeneration and restores normal lifespan in tau P301L mice.

Tau pathogenicity in Alzheimer's disease and other tauopathies is thought to involve the generation of hyperphosphorylated, truncated, and oligomeric tau species with enhanced neurotoxicity, although the generative mechanisms and the implications for disease therapy are not well understood. Here, we report a striking rescue from mutant tau toxicity in the JNPL3 mouse model of tauopathy. We show that pathological activation of calpains gives rise to a range of potentially toxic forms of tau, directly, and by activating cdk5. Calpain overactivation in brains of these mice is accelerated as a result of the marked depletion of the endogenous calpain inhibitor, calpastatin. When levels of this inhibitor are restored in neurons of JNPL3 mice by overexpressing calpastatin, tauopathy is prevented, including calpain-mediated breakdown of cytoskeletal proteins, cdk5 activation, tau hyperphosphorylation, formation of potentially neurotoxic tau fragments by either calpain or caspase-3, and tau oligomerization. Calpastatin overexpression also prevents loss of motor axons, delays disease onset, and extends survival of JNPL3 mice by 3 months to within the range of normal lifespan. Our findings support the therapeutic promise of highly specific calpain inhibition in the treatment of tauopathies and other neurodegenerative states.

Protective effect of calpain inhibitor N-acetyl-L-leucyl-L-leucyl-L-norleucinal on acute alcohol consumption related cardiomyopathy.

Excessive alcohol consumption and alcoholism cause medical problems with high mortality and morbidity rates. In this study we aimed to decrease the alcohol related tissue damage by inhibiting calpain activation which plays an important role in apoptosis and necrosis, in rats with cardiomyopathy induced by acute alcohol consumption. Male Sprague-Dawley rats were separated into four groups (control, vehicle, alcohol and alcohol + inhibitor) with 10 rats in each. Control group received isocaloric maltose while vehicle group received isocaloric maltose with DMSO, and alcohol group received 8 g/kg absolute ethanol by gavage. Inhibitor group received 20 mg/kg calpain inhibitor 1 intraperitonally prior to alcohol administration. Calpain activities, cathepsin L levels and cytochrome c release rates were significantly increased in alcohol group compared to control group (p < 0.05). Serum CK MB and BNP levels of alcohol group were excessively increased compared to control group (respectively p < 0.001 and p < 0.01). Serum BNP levels of alcohol + inhibitor group were significantly (p < 0.05) decreased compared to alcohol group. In addition to these, histological evaluation of light microscope images and the results of DNA fragmentation and immunohistochemical caspase-3 activity results showed significant improvement of these parameters in alcohol + inhibitor group compared to alcohol group. Results of our biochemical and histological evaluation results revealed that the calpain inhibitor N-acetyl-leu-leu-norleucinal may have an ameliorating effect on acute alcohol consumption related cardiac tissue damage due to its effects on cell death pathways.

Inhibition of calpains fails to improve regeneration through a peripheral nerve conduit.

Intramuscular injection of the calpain inhibitor leupeptin promotes peripheral nerve regeneration in primates (Badalamente et al., 1989 [13]), and direct positive effects of leupeptin on axon outgrowth were observed in vitro (Hausott et al., 2012 [12]). In this study, we applied leupeptin (2mg/ml) directly to collagen-filled nerve conduits in the rat sciatic nerve transection model. Analysis of myelinated axons and retrogradely labeled motoneurons as well as functional 'CatWalk' video analysis did not reveal significant differences between vehicle controls and leupeptin treated animals. Therefore, leupeptin does not improve nerve regeneration via protease inhibition in regrowing axons or in surrounding Schwann cells following a single application to a peripheral nerve conduit suggesting indirect effects on motor endplate integrity if applied systemically.

A cathepsin B inhibitor, E-64, improves the preimplantation development of bovine somatic cell nuclear transfer embryos.

Bovine somatic cell nuclear transfer (SCNT) is an important and powerful tool for basic research and biomedical and agricultural applications, however, the efficiency of SCNT has remained extremely low. In this study, we investigated the effects of cathepsin B inhibitor (E-64) supplementation of culture medium on in vitro development of bovine SCNT embryos. We initially used three concentrations of E-64 (0.1, 0.5, 1.0 µm), among which 0.5 µm resulted in the highest rate of blastocysts production after in vitro fertilization (IVF), and was therefore used for further experiments. Blastocyst development of SCNT embryos in the E-64 treatment group also increased relative to the control. Moreover, the cryosurvival rates of IVF and SCNT blastocysts were increased in E-64 treatment groups when compared with the control. On the other hand, we found that IVF and SCNT blastocysts derived from E-64-treated groups had increased total cell numbers and decreased apoptotic nuclei. Furthermore, assessment of the expression of apoptosis-related genes (Bax and Bcl-xL) in bovine IVF and SCNT blastocysts treated with E-64 by real-time RT-PCR analysis revealed suppressed expression of the pro-apoptotic gene Bax and stimulated expression of the anti-apoptotic gene Bcl-xL. Taken together, these finding indicate that addition of E-64 to embryo culture medium may have important implications for improving developmental competence and preimplantation quality in bovine IVF and SCNT embryos.

Population pharmacokinetic and pharmacodynamic modeling of different formulations of ONO-5334, cathepsin K inhibitor, in Caucasian and Japanese postmenopausal females.

ONO-5334, a selective inhibitor of cathepsin K, is a potential new treatment for osteoporosis. The objectives of this study were to (1) develop population pharmacokinetic-pharmacodynamic (PK-PD) models for ONO-5334 using dose-ascending data from healthy postmenopausal females, (2) examine comparability of PK and/or PD profile between Caucasian and Japanese, and (3) compare PK-PD profile between immediate release tablet (IRT) and sustained release tablet (SRT). The population PK-PD models were developed for each formulation for post-dose levels of bone resorption markers (serum CTX and NTX). The data were provided from 4 phase 1 studies with total of 201 Caucasian and 94 Japanese subjects. Plasma concentrations of ONO-5334 and bone resorption markers were thoroughly evaluated in those studies. An indirect response model described relationships between bone resorption markers and plasma concentrations of ONO-5334. There was no significant difference in PK and pharmacodynamic potency (IC50 ) between Caucasian and Japanese. Based on the developed model, serum CTX and NTX after administration of ONO-5334 IRT or SRT were simulated, and the results showed that ONO-5334 SRT would provide comparable PD effect on bone resorption markers with lower dose relative to IRT.

Induction of autophagy by cystatin C: a potential mechanism for prevention of cerebral vasospasm after experimental subarachnoid hemorrhage.

BACKGROUND: Studies have demonstrated that autophagy pathways are activated in the brain after experimental subarachnoid hemorrhage (SAH) and this may play a protective role in early brain injury. However, the contribution of autophagy in the pathogenesis of cerebral vasospasm (CVS) following SAH, and whether up-regulated autophagy may contribute to aggravate or release CVS, remain unknown. Cystatin C (CysC) is a cysteine protease inhibitor that induces autophagy under conditions of neuronal challenge. This study investigated the expression of autophagy proteins in the walls of basilar arteries (BA), and the effects of CysC on CVS and autophagy pathways following experimental SAH in rats. METHODS: All SAH animals were subjected to injection of 0.3 mL fresh arterial, non-heparinized blood into the cisterna magna. Fifty rats were assigned randomly to five groups: control group (n = 10), SAH group (n = 10), SAH + vehicle group (n = 10), SAH + low dose of CysC group (n = 10), and SAH + high dose of CysC group (n = 10). We measured proteins by western blot analysis, CVS by H&E staining method, morphological changes by electron microscopy, and recorded neuro-behavior scores. RESULTS: Microtubule-associated protein light chain-3, an autophagosome biomarker, and beclin-1, a Bcl-2-interacting protein required for autophagy, were significantly increased in the BA wall 48 h after SAH. In the CysC-handled group, the degree of CVS, measured as the inner BA perimeter and BA wall thickness, was significantly ameliorated in comparison with vehicle-treated SAH rats. This effect paralleled the intensity of autophagy in the BA wall induced by CysC. CONCLUSIONS: These results suggest that the autophagy pathway is activated in the BA wall after SAH and CysC-induced autophagy may play a beneficial role in preventing SAH-induced CVS.

Direct intranigral administration of an ubiquitin proteasome system inhibitor in rat: behavior, positron emission tomography, immunohistochemistry.

Several independent lines of research suggest that disruption of the ubiquitin proteasome system (UPS) may play a role in the pathophysiology of Parkinson's disease. Direct intracerebral injection of UPS inhibitors (e.g. lactacystin) in animals has consistently produced important features of the disease. In this study, a range of lactacystin doses (0.5, 1, 2, 10 and 20 µg) were injected into the right substantia nigra in rats to determine the ideal dose required to produce a robust and specific lesion of the dopamine nigro-striatal system and motor deficits. Motor behavior, assessed with the tapered ledged beam task, was severely affected in animals that received high doses (10 and 20 µg) but only mild, impairments were observed in animals that received low doses (0.5, 1, and 2 µg). Positron emission tomography was performed with a dedicated small animal scanner on the rats following the injection of the radio-labeled tracer (±)[(11)C]dihydrotetrabenazine (DTBZ) which labels vesicular monoamine transporter type 2. Severe loss of [(11)C]DTBZ binding in the ipsilateral striatum was observed in the higher dose groups and mild loss was observed in the low dose groups. Stereological cell counting of tyrosine hydroxylase immunoreactive cells in the substantia nigra and the ventral tegmental area indicated a dose dependent loss of dopaminergic neurons. Significant correlations were found between the behavioral motor deficits, striatal [(11)C]DTBZ binding and cell counts of tyrosine hydroxylase immunoreactive cells. Taken together these results indicate that intranigral injection of lactacystin produces dose dependent effects on the dopamine nigro-striatal system and a dose of 10 µg will produce a consistent severe lesion.