Amyloid-β induces NLRP1-dependent neuronal pyroptosis in models of Alzheimer's disease

Increasing evidence has shown the aberrant expression of inflammasome-related proteins in Alzheimer's disease (AD) brain; these proteins, including NLRP1 inflammasome, are implicated in the execution of inflammatory response and pyroptotic death. Although current data are associated NLRP1 genetic variants with AD, the involvement of NLRP1 inflammasome in AD pathogenesis is still unknown. Using APPswe/PS1dE9 transgenic mice, we found that cerebral NLRP1 levels were upregulated. Our in vitro studies further showed that increased NLRP1-mediated caspase-1-dependent ‘pyroptosis' in cultured cortical neurons in response to amyloid-β. Moreover, we employed direct in vivo infusion of non-viral small-interfering RNA to knockdown NLRP1 or caspase-1 in APPswe/PS1dE9 brain, and discovered that these NLRP1 or caspase-1 deficiency mice resulted in significantly reduced neuronal pyroptosis and reversed cognitive impairments. Taken together, our findings indicate an important role for NLRP1/caspase-1 signaling in AD progression, and point to the modulation of NLRP1 inflammasome as a promising strategy for AD therapy.

16S rDNA-based metagenomic analysis of dental plaque and lung bacteria in patients with severe acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVE

Acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) are leading causes of mortality in hospital intensive care units. We sought to determine whether dental plaque biofilms might harbor pathogenic bacteria that can eventually cause lung infections in patients with severe AE-COPD.

MATERIAL AND METHODS

Paired samples of subgingival plaque biofilm and tracheal aspirate were collected from 53 patients with severe AE-COPD. Total bacterial DNA was extracted from each sample individually for polymerase chain reaction amplification and/or generation of bacterial 16S rDNA sequences and cDNA libraries. We used a metagenomic approach, based on bacterial 16S rDNA sequences, to compare the distribution of species present in dental plaque and lung.

RESULTS

Analysis of 1060 sequences (20 clones per patient) revealed a wide range of aerobic, anaerobic, pathogenic, opportunistic, novel and uncultivable bacterial species. Species indistinguishable between the paired subgingival plaque and tracheal aspirate samples (97-100% similarity in 16S rDNA sequence) were dental plaque pathogens (Aggregatibacter actinomycetemcomitans, Capnocytophaga sputigena, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola) and lung pathogens (Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa and Streptococcus pneumoniae). Real-time polymerase chain reaction of 16S rDNA indicated lower levels of Pseudomonas aeruginosa and Porphyromonas gingivalis colonizing the dental plaques compared with the paired tracheal aspirate samples.

CONCLUSION

These results support the hypothesis that dental bacteria may contribute to the pathology of severe AE-COPD.

Morphologic control of Sb-rich Sb2Se3 to adjust its catalytic hydrogenation properties for p-nitrophenol

Sb-rich Sb₂Se₃ with hollow sphere morphology is an efficient catalyst for the hydrogenation of p-nitrophenol.

Combined PKC and MEK inhibition in uveal melanoma with GNAQ and GNA11 mutations

Uveal melanoma (UM) is a genetically and biologically distinct type of melanoma, and once metastatic there is no effective treatment currently available. Eighty percent of UMs harbor mutations in the Gαq family members GNAQ and GNA11. Understanding the effector pathways downstream of these oncoproteins is important to identify opportunities for targeted therapy. We report consistent activation of the protein kinase C (PKC) and MAPK pathways as a consequence of GNAQ or GNA11 mutation. PKC inhibition with AEB071 or AHT956 suppressed PKC and MAPK signalling and induced G1 arrest selectively in melanoma cell lines carrying GNAQ or GNA11 mutations. In contrast, treatment with two different MEK inhibitors, PD0325901 and MEK162, inhibited the proliferation of melanoma cell lines irrespective of their mutation status, indicating that in the context of GNAQ or GNA11 mutation MAPK activation can be attributed to activated PKC. AEB071 significantly slowed the growth of tumors in an allograft model of GNAQ(Q209L)-transduced melanocytes, but did not induce tumor shrinkage. In vivo and in vitro studies showed that PKC inhibitors alone were unable to induce sustained suppression of MAP-kinase signaling. However, combinations of PKC and MEK inhibition, using either PD0325901or MEK162, led to sustained MAP-kinase pathway inhibition and showed a strong synergistic effect in halting proliferation and in inducing apoptosis in vitro. Furthermore, combining PKC and MEK inhibition was efficacious in vivo, causing marked tumor regression in a UM xenograft model. Our data identify PKC as a rational therapeutic target for melanoma patients with GNAQ or GNA11 mutations and demonstrate that combined MEK and PKC inhibition is synergistic, with superior efficacy compared to treatment with either approach alone.

Surface anatomical profile of the cerebral cortex in obsessive-compulsive disorder: a study of cortical thickness, folding and surface area

BACKGROUND

Studying the distribution of anatomical abnormalities over the entire cortical surface can help to identify key neural circuits implicated in generating symptoms of neuropsychiatric disorders. There is a significant inconsistency among studies investigating the neuroanatomy of obsessive-compulsive disorder (OCD) because of the confounding influence of co-morbid depression and medication use and the lack of unbiased estimation of whole-brain morphometric changes. It is also unknown whether the distinct surface anatomical properties of thickness, surface area and gyrification, which collectively contribute to grey matter volume (GMV), are independently affected in OCD. Method The cortical maps of thickness, gyrification and surface areal change were acquired from 23 unmedicated OCD patients and 20 healthy controls using an unbiased whole-brain surface-based morphometric (SBM) method to detect regional changes in OCD. Subcortical structures were not assessed in this study.

RESULTS

Patients showed a significant increase in the right inferior parietal cortical thickness. Significant increases in gyrification were also noted in the left insula, left middle frontal and left lateral occipital regions extending to the precuneus and right supramarginal gyrus in OCD. Areal contraction/expansion maps revealed no significant regional differences between the patients and controls. In patients, gyrification of the insula significantly predicted the symptom severity measured using Yale-Brown Obsessive-Compulsive Scale (YBOCS).

CONCLUSIONS

An alteration in the cortical surface anatomy is an important feature of OCD seen in unmedicated samples that relates to the severity of the illness. The results underscore the presence of a neurodevelopmental aberration underlying the pathophysiology of OCD.

The effects of Porphyromonas gingivalis on the cell cycle progression of human gingival epithelial cells

OBJECTIVE

Porphyromonas gingivalis is a major pathogen in the development and progression of periodontal disease. The interactions or cross-talk between bacteria and gingival epithelial cells drive bacteria to manipulate the cell cycle to favor bacterial survival and virulence expression within the host. This study aims to dissect the effects of P. gingivalis on the cell cycle in human gingival epithelial cells.

MATERIALS AND METHODS

We established a model of P. gingivalis invading IHGE cells. The cell cycle distribution of human gingival epithelial cells was analyzed by flow cytometry. Cyclin D and cyclin E mRNA and protein were detected by real-time PCR and Western blot, respectively.

RESULTS

Porphyromonas gingivalis-induced facilitation of cell growth was correlated with the acceleration of G1 phase of cell cycle. Cyclin D1 mRNA levels were significantly upregulated from 6 to 12 h after infection. Cyclin E protein and mRNA levels were elevated at 10 and 12 h after invasion.

CONCLUSIONS

We confirmed that P. gingivalis significantly enhances IHGE cell proliferation by promoting the G1/S transition, involving the up-regulation of cyclin D and cyclin E.

Type II EATL (epitheliotropic intestinal T-cell lymphoma): a neoplasm of intra-epithelial T-cells with predominant CD8αα phenotype

In this multicentre study, we examined 60 cases of Type II enteropathy-associated T-cell lymphoma (EATL) from the Asia-Pacific region by histological review, immunohistochemistry and molecular techniques. Patients were mostly adult males (median age: 58 years, male:female 2.6:1), presenting with abdominal pain (60%), intestinal perforation (40%) and weight loss (28%). None had a history of coeliac disease and the median survival was only 7 months. Histologically, these tumours could be divided into (i) central tumour zone comprising a monotonous population of neoplastic lymphocytes, (ii) peripheral zone featuring stunted villi and morphologically atypical lymphocytes showing epitheliotropism, and (iii) distant mucosa with normal villous architecture and cytologically normal intra-epithelial lymphocytes (IELs). Characterized by extensive nuclear expression of Megakaryocyte-associated tyrosine kinase (MATK) (87%) and usually a CD8(+)CD56(+) (88%) cytotoxic phenotype, there was frequent aberrant expression of CD20 (24%). T-cell receptor (TCR) expression was silent or not evaluable in 40% but of the remainder, there was predominant expression of TCRαβ over TCRγδ (1.6:1). In keeping with the normal ratio of IEL subsets, CD8(+) cases showed predominant CD8αα homodimer expression (77%), regardless of TCR lineage. These tumours constitute a distinct entity from classical EATL, and the pathology may reflect tumour progression from IEL precursors, remnants of which are often seen in the distant mucosa.

Diabetes management in Australian rural aged care facilities: A cross--sectional audit

BACKGROUND

There is gap in the literature regarding the current practice of diabetes management of the elderly in Australia and its compliance with available Australian diabetes practice guidelines.

AIMS

The aims of this study were to describe the pharmacological management of elderly residents with diabetes living in aged care facilities and to identify areas for improvement in the current management as recommended by the current diabetes management guidelines in Australia.

METHOD

Residents with diabetes from three rural aged care facilities were identified by nursing staff. A cross-sectional medical record audit was carried out to obtain data of residents diagnosed with diabetes. Thirty-four medical records were audited from three aged care facilities.Data including demographics, medical histories and medications were collected and analysed.

RESULTS

This study had two key findings; Firstly, it showed that about a third of residents with type 2 diabetes are managed with diet only. Secondly, of the residents who are managed with medications, less than half of those audited (41%) were managed according to the current diabetes guidelines in terms of pharmacological treatment which included anti- hypertensive, lipid lowering and anti- platelet therapies. Of those patients with a history of CVD, all were receiving an antihypertensive medication, 71% were not managed for their lipids and 20% were not on any prophylactic anti- platelet therapy.

CONCLUSION

Management of patients with diabetes living in rural aged care facilities is inconsistent with the current management guidelines. Educational interventions targeting health professionals and patients might be beneficial to increase compliance with the current diabetes guidelines.

Novel quantum dots-carboxymethyl chitosan nanocomposite nitric oxide donors capable of detecting release of nitric oxide in situ

Nitric oxide (NO) donor compounds are primarily monofunctional in that they release NO under the requisite conditions. To detect the amount and duration of NO released, subsequent analysis methods are required. It would be advantageous if a NO donor compound could both release and detect NO at the same time. This would eliminate potential errors in the analysis. In this paper, novel cadmium telluride quantum dots (CdTe QD)-carboxymethyl chitosan (CMCS) nanocomposite NO donors, including both diazeniumdiolates and fluorescence probes, were fabricated by first synthesizing CdTe QD in CMCS aqueous solution and then reacting NO as well as ethyl bromide with the resultant CdTe QD-CMCS nanocomposites. Transmission electron microscopy, scanning electron microscopy and particle size analysis were used to examine the morphology and size distribution of the CdTe QD-CMCS nanocomposite NO donors. The donors are nanospheres with CdTe QD encapsulated and have dimensions of ~300 nm. Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and contact angle tests were employed to characterize the chemical structure of the donors, and the results also show that CdTe QD are well incorporated into CMCS, and many of them are close to the surface of the donors. The precursors of the donors exhibit a fluorescent effect, and the fluorescence can be quenched by NO. The donors can release NO spontaneously in a phosphate-buffered saline solution similar to a physiological environment, and can quantitatively detect the release of NO in situ based on fluorescence quenching of the donors by the NO.

Mode-dependent effect of high-frequency electrical stimulation of the anterior thalamic nucleus on amygdala-kindled seizures in rats

Deep brain stimulation (DBS) is an emerging treatment of epilepsy. Anterior nucleus of the thalamus (ANT) is considered to be an attractive target due to its close connection to the limbic structures and wide regions of neocortex. The present study aimed to investigate the effects of high frequency stimulation (HFS) targeting the ANT on amygdala-kindled seizures in Wistar rats in two different stimulation modes i.e. pre-treatment and post-treatment stimulations, mimicking the scheduled and responsive stimulations in clinical use respectively. When fully-kindled seizures were achieved by daily amygdala kindling (1 s train of 1 ms pulses at 60 Hz), HFS (15 min train of 100 μs pulses at 150 Hz and 450-800 μA) was applied in two modes for 10 days. Bilateral post-treatment with HFS reduced the incidence of generalized seizures and the mean behavioral seizure stage and shortened average afterdischarge duration (ADD) and generalized seizure duration (GSD), while bilateral pre-treatment with HFS resulted in a similar but much weaker inhibition of seizures. On the other hand, we also found the two stimulation modes both increased the afterdischarge threshold (ADT) and the differences of current intensity between ADT and generalized seizure threshold (GST) i.e. Δ(GST-ADT). However, Δ(GST-ADT) increased by at least 20 μA in bilateral post-treatment group, while less in bilateral pre-treatment group. Additionally, unilateral post-treatment with HFS failed to inhibit seizures. Our data show that anti-epileptic effect of bilateral post-treatment with HFS of ANT is much stronger than that of bilateral pre-treatment HFS, indicating bilateral responsive stimulation might be more appropriate for clinical anti-epileptic treatment of ANT HFS.

Analysis of polysorbate 80 and its related compounds by RP-HPLC with ELSD and MS detection

The chemical composition of polysorbate 80 strongly influences the physicochemical properties and performance of many products. Consequently, a reliable characterization of polysorbate 80 is crucial for many applications. However, the exact composition of these chemical mixtures cannot be determined by colorimetry, hydrolysis, size-exclusion chromatography, nuclear magnetic resonance or mass spectrometry (MS). Meanwhile, due to the strong retention of higher esters on the reversed-phase (RP) column, the published high-performance liquid chromatography (HPLC) methods suffered from inadequate elution. In the present paper, an HPLC-evaporative light scattering detection (ELSD) and an HPLC-electrospray ionization (ESI)-MS method were developed and validated for the separation and identification of the chemical composition of polysorbate 80. A full separation of the entire composition was achieved in 45 min. In the HPLC-ESI-MS spectra, each class of the compound in polysorbate 80 was directly confirmed and identified by [M + NH(4)](+) and [M + 2NH(4)](2+) ions. The number of polyoxyethylene groups and their distribution within the molecule were determined, in addition to the dehydration and esterification degree of sorbitol. Analysis showed that polysorbate 80 contained different proportions of components (polyoxyethylene sorbitan, polyoxyethylene isosorbide, polyoxyethylene sorbitan monooleate-dioesters-trioleates-tetraoleates and polyoxyethylene isosorbide monoester-dioesters). It was concluded that HPLC-ESI-MS is a useful tool for establishing the compositional profile of polysorbate 80.

Socioeconomic status and children with intellectual disability in China

BACKGROUND

Intellectual disability (ID) accounts for 70% of all disabilities among children in China's Second National Sampling Survey on Disability. Although studies have shown a relationship between social class and ID in children, none have investigated the association of socioeconomic variables in Chinese children with mild or severe ID.

METHODS

Data for children aged 0-6 years with and without ID were abstracted from the Second National Sampling Survey on Disability in China, conducted in 2006. Crude odds ratios showed the effect of sociodemographic factors on mild and severe ID. Adjusted odds ratios (OR(a) ) (95% confidence intervals) estimated the independent effects of these factors.

RESULTS

For both mild and severe ID, risk of having ID increased with male sex, birth to a woman aged 35 years and older, lower maternal education, mother's older age at delivery, lower income and rural residence. After age, gender and parent disability were controlled, mothers aged 35 years and older were more likely to have a child with ID: mild ID, OR(a) 1.47 (1.15-1.88); severe ID, OR(a) 1.32 (1.00-1.73). There was an approximate increasing monotonic risk of severe ID with increasing socioeconomic disadvantage: lowest income, OR(a) 3.00 (2.19-4.12); low income, OR(a) 2.28 (1.63-3.19); lower middle income, OR(a) 1.72 (1.27-2.33); middle income, OR(a) 1.73 (1.28-2.36).

CONCLUSIONS

There is a significant relationship between sociodemographic factors and ID. Similar patterns were found for both mild and severe ID. Recommendations are given for preventing ID in Chinese children.

GABAergic excitotoxicity injury of the immature hippocampal pyramidal neurons' exposure to isoflurane

BACKGROUND

Certain anesthetics exhibit neurotoxicity in the brains of immature but not mature animals. γ-Aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, is excitatory on immature neurons via its action at the GABAA receptor, depolarizing the membrane potential and inducing a cytosolic Ca2+ increase ([Ca2+]i), because of a reversed transmembrane chloride gradient. Recent experimental data from several rodent studies have demonstrated that exposure to isoflurane during an initial phase causes neuronal excitotoxicity and apoptosis. GABAA receptor-mediated synaptic voltage-dependent calcium channels' (VDCCs) overactivation and Ca2+ influx are involved in these neural changes.

METHODS

We monitored [Ca2+]i using Fluo-4 AM fluorescence imaging. Using whole-cell patch clamp techniques, IVDCC (voltage-dependent calcium channel currents) were recorded from primary cultures of rat hippocampal neurons (5-day culture) exposed to isoflurane. To further investigate the neurotoxicity of high cytosolic-free calcium after isoflurane in a dose- and time-dependent manner, the possibility of increased caspase-3 levels was evaluated by Western blot and quantitative real-time polymerase chain reaction. Statistical significance was assessed using the Student t test or 1-way analysis of variance followed by the Tukey post hoc test.

RESULTS

Under control conditions, isoflurane enhanced the GABA-induced [Ca2+]i increase in a dose-dependent manner. Dantrolene and nicardipine markedly inhibited this enhancement mediated by isoflurane. Moreover, in Ca2+-free media, pretreatment with isoflurane did not show any influence on the caffeine-induced increase of [Ca2+]i. Similarly, using whole-cell recording, isoflurane increased the peak amplitude of IVDCC in the cultured neurons from rat hippocampus by depolarization pulses. Isoflurane (0.25, 0.5, 0.75, and 1 minimum alveolar concentration [MAC]) potentiated IVDCC peak current amplitude by 109.11%±9.03%, 120.56%±11.46%, 141.33%±13.87%, and 146.78%±15.87%, respectively. To analyze variation in protein levels, the effect of treatments with isoflurane on caspase-3 activity was dose- and time-dependent, reaching a maximal caspase-3 activity after exposure to 1 MAC for 6 hours (P<0.001). However, in the mRNA levels, hippocampal caspase-3 mRNA levels began to be significantly increased in isoflurane-treated developing rat hippocampal neurons after 6 hours of exposure to 0.25 MAC isoflurane (P<0.001).

CONCLUSIONS

Isoflurane-mediated enhancement of GABA-triggered [Ca2+]i release results from membrane depolarization with subsequent activation of VDCCs and further Ca2+-induced Ca2+ release from the ryanodine-sensitizing Ca2+ store. An increase in [Ca2+]i, caused by activation of the GABAA receptor and opening of VDCCs, is necessary for isoflurane-induced calcium overload of immature rat hippocampal neurons, which may be involved in the mechanism of an isoflurane-induced neurotoxic effect in the developing rodent brain.

Diazoxide decreases ischemia-reperfusion injury in a rat model of lung transplantation

BACKGROUND

Ischemia-reperfusion injury (IRI) is a significant factor contributing to primary graft failure in lung transplantation. Given a pivotal role of mitochondria in IRI-related molecular events, the effects of diazoxide, a selective opener of mitochondrial adenosine-5'-triphosphate (ATP)-sensitive potassium channels (mitoK(ATP)), on IRI were investigated in a rat model of lung transplantation.

METHODS

The 108 rats were randomly assigned to 5 groups; a sham-operated, 2 control, and 2 experimental groups that received either diazoxide alone or a combination of diazoxide with 5-hydroxydecanoate sodium salt. Lung injuries were assessed by multiple parameters at 2 hours or 24 hours after reperfusion, including oxygenation index, wet/dry weight ratio of transplanted lungs, lung morphology, as well as measurements of myeloperoxidase, malondialdehyde, total antioxidant capacity, tumor necrosis factor-α, and interleukin-6.

RESULTS

Compared with the sham group, the 2 control groups revealed significant changes among most parameters of lung injury measured at either 2 hours or 24 hours after reperfusion. The extent of the changes was dramatically reduced by the administration of diazoxide. Importantly, the protective effect of diazoxide was almost completely reversed by co-administration of 5-hydroxydecanoate sodium salt, a selective blocker of mitoK(ATP).

CONCLUSIONS

These data provide evidence for substantial protective effects of diazoxide in an in vivo rat lung IRI model. Pharmacological modulation of mitoK(ATP) may be a potential strategy to reduce IRI-induced primary graft failure in lung transplantation.

ZD6474, a small molecule tyrosine kinase inhibitor, potentiates the anti-tumor and anti-metastasis effects of radiation for human nasopharyngeal carcinoma

PURPOSE

To investigate the capacity for ZD6474, a small molecule tyrosine kinase inhibitor, to enhance anti-tumor and anti-metastasis effects of radiation on human nasopharyngeal carcinoma (NPC).

EXPERIMENTAL DESIGN

NPC cell lines and xenograft models were evaluated following treatment with ZD6474 and radiation alone and in combination compared with untreated control mice.

RESULTS

Treatment with ZD6474 enhanced the anti-proliferative effect of radiation on NPC cell lines as detected by cell proliferation and apoptosis assays. ZD6474 also induced a significant increase in the radiosensitivity of NPC cells, with radiation enhancement ratios (RERs) ranging from 1.2 to 1.6. Despite the cytotoxicity exhibited by NPC cells following radiotherapy, the invasion and migration of NPC cells was found to be unaffected. In contrast, treatment with ZD6474 strongly inhibited the invasion and migration of NPC cells. When the administration of radiation and ZD6474 was investigated in vitro, the ability of ZD6474 to inhibit activation of the pro-survival signaling pathways induced by radiation was demonstrated. In vivo, ZD6474 significantly enhanced the anti-metastasis effects of radiation, while treatment with radiation and ZD6474 was found to be well tolerated and resulted in a strong inhibition of tumor growth.

CONCLUSIONS

Our results suggest the combination of radiation and ZD6474 represents a promising strategy for the treatment of human NPC.