Death-associated protein kinase 1 is associated with cognitive dysfunction in major depressive disorder.

We previously showed that death-associated protein kinase 1 (DAPK1) expression is increased in hippocampal tissue in a mouse model of major depressive disorde and is related to cognitive dysfunction in Alzheimer's disease. In addition, depression is a risk factor for developing Alzheimer's disease, as well as an early clinical manifestation of Alzheimer's disease. Meanwhile, cognitive dysfunction is a distinctive feature of major depressive disorder. Therefore, DAPK1 may be related to cognitive dysfunction in major depressive disorder. In this study, we established a mouse model of major depressive disorder by housing mice individually and exposing them to chronic, mild, unpredictable stressors. We found that DAPK1 and tau protein levels were increased in the hippocampal CA3 area, and tau was hyperphosphorylated at Thr231, Ser262, and Ser396 in these mice. Furthermore, DAPK1 shifted from axonal expression to overexpression on the cell membrane. Exercise and treatment with the antidepressant drug citalopram decreased DAPK1 expression and tau protein phosphorylation in hippocampal tissue and improved both depressive symptoms and cognitive dysfunction. These results indicate that DAPK1 may be a potential reason and therapeutic target of cognitive dysfunction in major depressive disorder.

Curcumin Exerts Effects on the Pathophysiology of Alzheimer's Disease by Regulating PI(3,5)P2 and Transient Receptor Potential Mucolipin-1 Expression.

BACKGROUND: To validate our speculation that curcumin may ameliorate Alzheimer's disease (AD) pathogenesis by regulating PI(3,5)P2 and transient receptor potential mucolipin-1 (TRPML1) expression levels. METHODS: We developed an animal model presenting AD by APP/PS1 transgenes. The mouse clonal hippocampal neuronal cell line HT-22 was treated with amyloid-ß1-42 (Aß1-42). Curcumin was administrated both in vivo and in vitro. MTS assay was used to detect cell viability, and the lysosomal [Ca2+] ion concentration was detected. The number of autophagosomes was detected by the transmission electron microscopic examination. Illumina RNA-seq was used to analyze the different expression patterns between Aß1-42-treated cells without and with curcumin treatment. The protein level was analyzed by the Western blotting analysis. PI(3,5)P2 or TRPML1 was knocked down in HT-22 cells or in APP/PS1 transgenic mice. Morris water maze and recognition task were performed to trace the cognitive ability. RESULTS: Curcumin increased cell viability, decreased the number of autophagosomes, and increased lysosomal Ca2+ levels in Aß1-42-treated HT-22 cells. Sequencing analysis identified TRPLML1 as the most significantly upregulated gene after curcumin treatment. Western blotting results also showed that TRPML1 was upregulated and mTOR/S6K signaling pathway was activated and markers of the autophagy-lysosomal system were downregulated after curcumin use in Aß1-42-treated HT-22 cells. Knockdown of PI (3,5)P2 or TRPML1 increased the protein levels of markers of the autophagy-lysosomal system after curcumin use in Aß1-42-treated HT-22 cells, inhibited mTOR/S6K signaling pathway, increased the protein levels of markers of the autophagy-lysosomal system after curcumin use in APP/PS1 mice. Besides, knockdown of PI(3,5)P2 or TRPML1 reversed the protective role of curcumin on memory and recognition impairments in mice with APP/PS1 transgenes. CONCLUSION: To some extent, it suggested that the effects of curcumin on AD pathogenesis were, at least partially, associated with PI(3,5)P2 and TRPML1 expression levels.

The Use of Solitaire AB Stents in Coil Embolization of Wide-Necked Cerebral Aneurysms.

BACKGROUND: The Solitaire AB stent is one of many assistant stents used for treating wide-necked cerebral aneurysm, and has been used since 2003. However, large sample studies on its safety and effectiveness are lacking. The objective of this study was to evaluate the effectiveness and safety of the Solitaire AB stent in the coil embolization of wide-necked cerebral aneurysms. METHODS: Retrospective review of the clinical and image data of 116 patients with wide-necked cerebral aneurysms who had been enrolled at six interventional neuroradiology centers from February 2010 to February 2014 and had been treated by coil embolization; in total, 120 Solitaire AB stents were used. The degree of aneurysm occlusion was examined using digital subtraction angiography (DSA) immediately after the procedure and during follow-up, and was graded using the modified Raymond classification. We also observed complications to evaluate the safety and effectiveness of this therapy. RESULTS: The 120 Solitaire AB stents (4 mm × 15 mm, four stents; 4 mm × 20 mm, 16 stents; 6 mm × 20 mm, 36 stents; 6 mm × 30 mm, 64 stents) were inserted to treat 120 wide-necked cerebral aneurysms. All stents were inserted successfully. DSA immediately post-surgery revealed 55 cases of complete occlusion, 59 cases of neck remnant, and six cases of aneurysm remnant. Perioperatively, there were four cases of hemorrhage and four cases of stent thrombosis. The follow-up spanned 3-37 months; of 92 patients examined by DSA at the 6-month follow up, 12 had disease recurrence. CONCLUSIONS: The Solitaire AB stent is effective with a good technical success rate and short-term effect for assisting coil embolization of wide-necked cerebral aneurysms.

Catalpol provides protective effects against cerebral ischaemia/reperfusion injury in gerbils.

OBJECTIVES: To investigate the protective effect of catalpol on cerebral ischaemia/reperfusion (CI/R) injury in gerbils and further explore the underlying mechanism. METHODS: A gerbil model of CI/R was prepared by bilateral common carotid occlusion for 10 min followed by 6 h reperfusion. Catalpol (5, 10 or 20 mg/kg per day) was injected intraperitoneally for 3 days before the carotid occlusion. Stroke index was measured during the reperfusion. The contents of endogenous neuropeptides, endothelin-1 (ET-1) and calcitonin gene-related peptide in plasma were evaluated by radioimmunoassay. Superoxide dismutase (SOD) and malondialdehyde (MDA) in brain tissue homogenate were also examined. KEY FINDINGS: The results showed that catalpol significantly improved the stroke index compared with CI/R control group (P < 0.05 or P < 0.01). Catalpol significantly increased the activity of SOD at the doses of 10 and 20 mg/kg (P ≤ 0.05), decreased the brain MDA content and the plasma level of ET-1 at the doses of 10 and 20 mg/kg (P ≤ 0.01). CONCLUSIONS: These data suggested that the efficacy of catalpol pretreatment on CI/R injury may be attributed to reduction of free radicals and inhibition of lipid peroxidation and ET-1 production.

Effects of catalpol on ATPase and amino acids in gerbils with cerebral ischemia/reperfusion injury.

This study aimed to investigate the effects of catalpol on ATPase and amino acids in gerbils following cerebral ischemia/reperfusion (CI/R) injury. Gerbil model of CI/R was prepared by bilateral common carotid occlusion for 10 min followed by 6 h of reperfusion. Catalpol (5, 10 or 20 mg/kg per day) was injected intraperitoneally for 3 days before the carotid occlusion. Stroke index was measured during the reperfusion. ATPase activity, glutamate (Glu) and aspartate contents in brain tissue homogenate were examined. The results showed that catalpol significantly improved the stroke index compared with sham group (P < 0.05 or P < 0.01). Catalpol markedly increased the activities of Na(+)-K(+)-ATPase and Ca(2+)-ATPase (P < 0.05 or P < 0.01), and significantly decreased the content of Glu in brain tissue (P < 0.05 or P < 0.01). These data suggest that the efficacy of catalpol pretreatment on CI/R injury is associated with the enhancement of ATPase activity and the inhibition of excitatory amino acid toxicity.

MicroRNA-195 downregulates Alzheimer's disease amyloid-ß production by targeting BACE1.

Alzheimer's disease (AD) is a progressive neurodegenerative disease, characterized by amyloid-beta (Aß) deposition and neurofibrillary tangles. Numerous microRNAs have been found to play crucial roles in regulating Aß production in the process of AD. Previous investigations have reported lower levels of many microRNAs in AD patients and animal models. Here, we examined the role of miR-195 in the process of Aß formation. Bioinformatics' algorithms predicted miR-195 binding sites within the beta-site APP cleaving enzyme 1 (BACE1) 3'-untranslated region (3'-UTR), and we found the level of miR-195 to be negatively related to the protein level of BACE1 in SAMP8 mice. We confirmed the target site in HEK293 cells by luciferase assay. Overexpression of miR-195 in N2a/WT cells decreased the BACE1 protein level, and inhibition of miR-195 resulted in increase of BACE1 protein level. Furthermore, overexpression of miR-195 in N2a/APP decreased the level of Aß, while inhibition of miR-195 resulted in an increase of Aß. Thus, we demonstrated that miR-195 could downregulate the level of Aß by inhibiting the translation of BACE1. We conclude that miR-195 might provide a therapeutic strategy for AD.

Gastrointestinal dysfunction in a Parkinson's disease rat model and the changes of dopaminergic, nitric oxidergic, and cholinergic neurotransmitters in myenteric plexus.

This study aims to explore the gastrointestinal dysfunction and the changes of dopaminergic, nitric oxidergic, and cholinergic neurons in the myenteric plexus of a Parkinson's disease (PD) rat model. A PD rat model was induced through unilateral substantia nigra administration of 6-hydroxydopamine. Four weeks later, the feces in 1 h and residual solid food in stomach at 2 h after feeding were measured. Changes in tyrosine hydroxylase (TH) in substantial nigra, TH, choline acetyltransferase (ChAT), and neuronal nitric oxide synthase (nNOS) in gastric antrum and colon tissue were examined by immunohistochemistry. Reverse transcription (RT) polymerase chain reaction (PCR) and Western blot were used to evaluate and compare the levels of messenger RNA (mRNA) and protein expression of TH, ChAT, and nNOS in the GI tract between normal and 6-hydroxydopamine-lesioned rats. Compared with control samples, the number of TH⁺ cells in the damaged side of substantia nigra of 6-hydroxydopamine-lesioned rats decreased significantly (P < 0.01). The weight and water content of the fecal matter decreased (P < 0.01), and the percentage of residual solid food increased (P < 0.01). The average integrated optical densities of TH-positive areas in the gastric antrum and colon tissue increased significantly (P < 0.01), nNOS decreased significantly (P < 0.01), and there were no significant changes in ChAT (P > 0.05). TH and nNOS mRNA levels in the gastric antrum and proximal colon decreased (P < 0.01), there were no significant changes in ChAT mRNA levels (P > 0.05). The protein levels of TH in the GI tract were significantly increased (P < 0.01), nNOS significantly decreased (P < 0.01), and ChAT had no significant changes (P > 0.05). 6-Hydroxydopamine-lesioned rats had delayed gastric emptying and constipation that might be related to the gastrointestinal TH increase and nNOS decrease. These symptoms were not related to changes in cholinergic transmitters.

Inhibition of caspase-3 activation and apoptosis is involved in 3-nitropropionic acid-induced ischemic tolerance to transient focal cerebral ischemia in rats.

Our aim was to investigate the involvement of caspase-3 activation and apoptotic cell death in mitochondrial toxin 3-nitropropionic acid (3-NPA)-induced ischemic tolerance to transient focal cerebral ischemia in rats. Rats were administrated either vehicle control or 3-NPA ip doses of 20 mg/kg. Three days later, rats were exposed to 2 h of middle cerebral artery occlusion, followed by 24 h of reperfusion. Infarct volumes were assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining 24 h after reperfusion. We measured neural cell apoptosis in the cerebral ischemic penumbra by terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) and flow cytometry (FCM). Cleavage of the fluorogenic substrate zDEVD-afc was used to assay caspase-3 activity. Compared with the vehicle-injected group, pretreatment with 3-NPA reduced the infarct volume by 22.3% and decreased the number of TUNEL-positive neural cells and apoptotic percentages by 47% (p <0.05) and 43.9% (p <0.01), respectively. In terms of caspase-3 activity in ischemic penumbral tissues, the 3-NPA-pretreated group showed 13.9% (p <0.05) less caspase-3 activity than the control group. The development of 3-NPA-induced ischemic tolerance in brain may be related to decreases in caspase-3 activation, which leads to decreased neural cell apoptosis.