Helicobacter pylori Usurps Cell Polarity to Turn the Cell Surface into a Replicative Niche

Helicobacter pylori (Hp) intimately interacts with the gastric epithelial surface and translocates the virulence factor CagA into host cells in a contact-dependent manner. To study how Hp benefits from interacting with the cell surface, we developed live-cell microscopy methods to follow the fate of individual bacteria on the cell surface and find that Hp is able to replicate and form microcolonies directly over the intercellular junctions. On polarized epithelia, Hp is able to grow directly on the apical cell surface in conditions that do not support the growth of free-swimming bacteria. In contrast, mutants in CagA delivery are defective in colonization of the apical cell surface. Hp perturbs the polarized epithelium in a highly localized manner, since wild-type Hp does not rescue the growth defect of the CagA-deficient mutants upon co-infection. CagA's ability to disrupt host cell polarity is a key factor in enabling colonization of the apical cell surface by Hp, as disruption of the atypical protein kinase C/Par1b polarity pathway leads to rescue of the mutant growth defect during apical infection, and CagA-deficient mutants are able to colonize the polarized epithelium when given access to the basolateral cell surface. Our study establishes the cell surface as a replicative niche and the importance of CagA and its effects on host cell polarity for this purpose

Electrosprayed Minocycline-loaded PLGA Microparticles for the Treatment of Glioblastoma

Background: Around 12,340 patients in the US are diagnosed with glioblastoma multiforme (GBM) yearly, and despite the current treatment options, such as chemotherapy, radiotherapy, surgical resection, or a combination of them, the median survival is only about 15 months after initial diagnosis. Minocycline, a tetracycline antibiotic, has shown to inhibit U87 glioblastoma cell death and inhibit angiogenesis, or the creation of new blood vessels as is often needed by the tumor to grow. The utilization of biomaterials such as poly lactic-co-glycolic acid (PLGA) can better sustain the release and bioactivity of loaded drugs. The use of polyethylene glycol (PEG), a hydrophilic polymer, may improve the encapsulation of minocycline into the PLGA microparticles, given its hydrophilic nature. Electrospraying may be a promising method to fabricate drug loaded PLGA microparticles with high drug loading and loading efficiency. Therefore, the objective of this project was to develop electrosprayed minocycline-loaded PLGA microparticles for the treatment of GBM. Methods: Minocycline-loaded PLGA microparticles were fabricated through electrospraying utilizing an 18 cm needle-tip to glass plate distance, 0.9 ml/hr flowrate, and 14 kV voltage. The solution consisted of 1 ml of chloroform as the solvent and 70 mg of PLGA as the polymer with different minocycline amounts and with or without polyethylene glycol (PEG). The amount of drug loaded into the microparticles was determined by dissolving the microparticles in 1 mL of dimethylsulfoxide and then measuring the absorbance of minocycline at 350 nm. Release kinetics studies were performed by placing the microparticles in phosphate-buffered saline and reading minocycline absorbance of the supernatant at various timepoint. Scanning Electron Microscopy (SEM) was used to determine size and morphology of the minocycline-loaded PLGA microparticles. Results: The amount of drug loading and loading efficiency increased with the addition of PEG (3.23 ± 0.29 vs. 4.02 ± 0.34 and 49.40 ± 4.49 vs. 64.30 ± 5.47%, respectively) and the utilization of higher amount of drug (4.02 ± 0.34 vs. 9.93 ± 0.64 and 64.30 ± 5.47 vs. 70.76 ± 4.57%, respectively). The release kinetics study demonstrated that the different microparticles experienced a burst release within the first hour (67-80%). The microparticles were spherical in shape and ranged between 4-11 μm in size. The addition of PEG resulted in the aggregation of the microparticles, as observed in SEM imaging. Conclusions: This study demonstrated that electrosprayed minocycline-loaded PLGA microparticles can be successfully fabricated with high drug loading and loading efficiency and have a spherical shape within the micron size range. PEG was able to increase drug loading of the lipophilic drug by increasing the solubility of the drug in the polymer/chloroform solution. However, the utilization of PEG affected the collection of the particles and therefore, further optimization of the electrospraying parameters needs to be done to improve the collection of non-aggregated microparticles. In addition, given their burst release of minocycline, the microparticles may need to be further encapsulated in a scaffold or depot to prolong their release of drug

Competing Active and Passive Interactions Drive Amoeba-like Crystallites and Ordered Bands in Active Colloids

Swimmers and self-propelled particles are physical models for the collective behaviour and motility of a wide variety of living systems, such as bacteria colonies, bird flocks and fish schools. Such artificial active materials are amenable to physical models which reveal the microscopic mechanisms underlying the collective behaviour. Here we study colloids in a DC electric field. Our quasi-two-dimensional system of electrically-driven particles exhibits a rich and exotic phase behaviour. At low field strengths, electrohydrodynamic flows lead to self-organisation into crystallites with hexagonal order. Upon self-propulsion of the particles due to Quincke rotation, we find an ordered phase of active matter in which the motile crystallites constantly change shape and collide with one another. At higher field strengths, this "dissolves" to an active gas. We parameterise a particulate simulation model which reproduces the experimentally observed phases and, at higher field strengths predicts an activity-driven demixing to band-like structures

The Application of Electrosprayed Minocycline-Loaded PLGA For The Treatment Of Glioblastoma

Background: Glioblastoma multiforme (GBM) is one of the most common and aggressive forms of cancer with unfavorable prognosis due to high levels of reoccurrence with around 10,000 patients in the U.S. diagnosed each year. Despite treatment with surgery, radiotherapy, and chemotherapy, survival rate for this disease is around 21 months after diagnosis. Minocycline, a tetracycline-derivative used as an antibiotic, has also demonstrated the ability to inhibit angiogenesis or tumor growth and, presents a possible treatment option for GBM. Methods: Microparticles were fabricated by electrospraying by varying solvent type, distance, flow rate, voltage, and polymer concentration as parameters. The cytotoxicity of endothelial and glioblastoma cells was determined by an MTT assay by determining the absorbance using a spectrophotometer at a wavelength of 350 nm. Scanning electron microscopy (SEM) imaging was used to image the samples to determine microparticle surface morphology and size via an electron beam due to microparticles being sputter coated with gold to generate an electrical conduction. Results: The electrospraying process consists of numerous parameters which directly affect the creation of microparticles. The use of the solvent methanol aids in dissolving minocycline, while the use of DCM is important for the process of electrospraying, due to its higher vapor pressure and ability to dissolve PLGA. Conclusion: In conclusion, electrospraying is a promising method to fabricate drug loaded PLGA microparticles. However, optimization is needed whenever there is a new drug of interest as it can modify the properties of the electrospray solution and result in different effects on the fabrication parameters and particles produced

APOE genotype and cognitive change in young, middle-aged, and older adults living in the community.

We examined whether the apolipoprotein E (APOE) ε4 allele was associated with cognitive benefits in young adulthood and whether it reversed to confer cognitive deficits in later life ("antagonistic pleiotropy") in the absence of dementia-related neuropathology. We also tested whether the ε2 allele was associated with disadvantages in early adulthood but offered protection against cognitive decline in early old age. Eight-year cognitive change was assessed in 2,013 cognitively normal community-dwelling adults aged 20-24, 40-44, or 60-64 years at baseline. Although cognitive decline was associated with age, multilevel models contrasting the ε2 and ε4 alleles provided no evidence that the APOE genotype was related to cognitive change in any of the age groups. The findings suggest that in the absence of clinically salient dementia pathology, APOE ε2 and ε4 alleles do not exhibit antagonistic pleiotropy in relation to cognition between the ages of 20 and 72 years

Vacuolating cytotoxin and variants in Atg16L1 that disrupt autophagy promote Helicobacter pylori infection in humans

Peer reviewedPreprin

Walking speed, cognitive function and dementia risk in the English Longitudinal Study

Background: Physical and cognitive function decline with age. Slow walking speed has been associated with negative health outcomes and dementia is often preceded by cognitive decline. This study investigated walking speed, cognitive function and the interaction between changes in these measures in relation to dementia risk. Method: Walking speed and cognition were assessed in 3,932 individuals aged ≥60 years at wave 1 (2002-03) and 2 (2004-05) of the English Longitudinal Study of Ageing. New dementia cases were assessed from wave 3 (2006-07) to wave 7 (2014-15). The associations were modelled using Cox proportional hazards regression. Results: Participants with faster baseline walking speeds (HR 0.36; 95% CI 0.22 - 0.60) had a decreased risk of dementia. Those who had a greater decline in walking speed (waves 1 - 2 (HR 1.23; 95% CI 1.03 - 1.47) had an increased dementia risk. Participants with greater baseline cognition (HR 0.42; 95% CI 0.34 - 0.54) had a reduced dementia risk. Those who had a greater decline in cognition (waves 1-2) had a greater risk of dementia (HR 1.78; 95% CI 36 1.53 - 2.06). Change in walking speed and change in cognition did not interact significantly in relation to dementia risk (HR 1.01; 95% CI 0.88 – 1.17). Conclusions: In this community-dwelling sample of English adults those with slower walking speeds and a greater decline in speed over time had an increased risk of developing dementia independent of changes in cognition. Further research is required to understand the mechanisms that may drive these associations

Caveolin-1 protects B6129 mice against Helicobacter pylori gastritis.

Caveolin-1 (Cav1) is a scaffold protein and pathogen receptor in the mucosa of the gastrointestinal tract. Chronic infection of gastric epithelial cells by Helicobacter pylori (H. pylori) is a major risk factor for human gastric cancer (GC) where Cav1 is frequently down-regulated. However, the function of Cav1 in H. pylori infection and pathogenesis of GC remained unknown. We show here that Cav1-deficient mice, infected for 11 months with the CagA-delivery deficient H. pylori strain SS1, developed more severe gastritis and tissue damage, including loss of parietal cells and foveolar hyperplasia, and displayed lower colonisation of the gastric mucosa than wild-type B6129 littermates. Cav1-null mice showed enhanced infiltration of macrophages and B-cells and secretion of chemokines (RANTES) but had reduced levels of CD25+ regulatory T-cells. Cav1-deficient human GC cells (AGS), infected with the CagA-delivery proficient H. pylori strain G27, were more sensitive to CagA-related cytoskeletal stress morphologies ("humming bird") compared to AGS cells stably transfected with Cav1 (AGS/Cav1). Infection of AGS/Cav1 cells triggered the recruitment of p120 RhoGTPase-activating protein/deleted in liver cancer-1 (p120RhoGAP/DLC1) to Cav1 and counteracted CagA-induced cytoskeletal rearrangements. In human GC cell lines (MKN45, N87) and mouse stomach tissue, H. pylori down-regulated endogenous expression of Cav1 independently of CagA. Mechanistically, H. pylori activated sterol-responsive element-binding protein-1 (SREBP1) to repress transcription of the human Cav1 gene from sterol-responsive elements (SREs) in the proximal Cav1 promoter. These data suggested a protective role of Cav1 against H. pylori-induced inflammation and tissue damage. We propose that H. pylori exploits down-regulation of Cav1 to subvert the host's immune response and to promote signalling of its virulence factors in host cells

Front Neurol

Objective: Recent research suggests that sleep disorders or changes in sleep stages or EEG waveform precede over time the onset of the clinical signs of pathological cognitive impairment (e.g., Alzheimer's disease). The aim of this study was to identify biomarkers based on EEG power values and spindle characteristics during sleep that occur in the early stages of mild cognitive impairment (MCI) in older adults. Methods: This study was a case-control cross-sectional study with 1-year follow-up of cases. Patients with isolated subjective cognitive complaints (SCC) or MCI were recruited in the Bordeaux Memory Clinic (MEMENTO cohort). Cognitively normal controls were recruited. All participants were recorded with two successive polysomnography 1 year apart. Delta, theta, and sigma absolute spectral power and spindle characteristics (frequency, density, and amplitude) were analyzed from purified EEG during NREM and REM sleep periods during the entire second night. Results: Twenty-nine patients (8 males, age = 71 +/- 7 years) and 29 controls were recruited at T0. Logistic regression analyses demonstrated that age-related cognitive impairment were associated with a reduced delta power (odds ratio (OR) 0.072, P < 0.05), theta power (OR 0.018, P < 0.01), sigma power (OR 0.033, P < 0.05), and spindle maximal amplitude (OR 0.002, P < 0.05) during NREM sleep. Variables were adjusted on age, gender, body mass index, educational level, and medication use. Seventeen patients were evaluated at 1-year follow-up. Correlations showed that changes in self-reported sleep complaints, sleep consolidation, and spindle characteristics (spectral power, maximal amplitude, duration, and frequency) were associated with cognitive impairment (P < 0.05). Conclusion: A reduction in slow-wave, theta and sigma activities, and a modification in spindle characteristics during NREM sleep are associated very early with a greater risk of the occurrence of cognitive impairment. Poor sleep consolidation, lower amplitude, and faster frequency of spindles may be early sleep biomarkers of worsening cognitive decline in older adults

Understanding the links between hearing impairment and dementia : development and validation of the social and emotional impact of hearing impairment (SEI-HI) questionnaire

Background The links between hearing impairment (HI) and dementia have been well documented, but factors mediating this relationship remain unknown. Major consequences of HI are social and emotional dysfunction, and as the risk of dementia increases linearly with the severity of HI, it is plausible that socio-emotional difficulties may play a role in this association. Objective The aim of this study was to develop and validate a tool to analyse levels of hearing-related disability, to investigate ultimately whether subjective disability contributes to risk of cognitive impairment compared with hearing thresholds alone. Methods Development and validation of the questionnaire, the Social and Emotional Impact of Hearing Impairment (SEI-HI), was conducted in four phases: (1) content; (2) scoring and outcomes; (3) validation; (4) feasibility in a sample of people with cognitive impairment. Results Considerable evidence was found for the internal and external reliability of the tool with high construct validity, concurrent validity and test-retest values of the SEI-HI questionnaire. A feasibility check on 31 patients with mild cognitive impairment or dementia showed the SEI-HI questionnaire was easy to administer and well-received. Conclusion The SEI-HI questionnaire is a relevant instrument to assess hearing-related disability which can be used in people with cognitive decline to assess further impact on risk of developing dementia