Multimodal fMRI Resting-State Functional Connectivity in Granulin Mutations: The Case of Fronto-Parietal Dementia

Background

Monogenic dementias represent a great opportunity to trace disease progression from preclinical to symptomatic stages. Frontotemporal Dementia related to Granulin (GRN) mutations presents a specific framework of brain damage, involving fronto-temporal regions and long inter-hemispheric white matter bundles. Multimodal resting-state functional MRI (rs-fMRI) is a promising tool to carefully describe disease signature from the earliest disease phase.

Objective

To define local connectivity alterations in GRN related pathology moving from the presymptomatic (asymptomatic GRN mutation carriers) to the clinical phase of the disease (GRN- related Frontotemporal Dementia).

Methods

Thirty-one GRN Thr272fs mutation carriers (14 patients with Frontotemporal Dementia and 17 asymptomatic carriers) and 38 healthy controls were recruited. Local connectivity measures (Regional Homogeneity (ReHo), Fractional Amplitude of Low Frequency Fluctuation (fALFF) and Degree Centrality (DC)) were computed, considering age and gender as nuisance variables as well as the influence of voxel-level gray matter atrophy.

Results

Asymptomatic GRN carriers had selective reduced ReHo in the left parietal region and increased ReHo in frontal regions compared to healthy controls. Considering Frontotemporal Dementia patients, all measures (ReHo, fALFF and DC) were reduced in inferior parietal, frontal lobes and posterior cingulate cortex. Considering GRN mutation carriers, an inverse correlation with age in the posterior cingulate cortex, inferior parietal lobule and orbitofrontal cortex was found.

Conclusions

GRN pathology is characterized by functional brain network alterations even decades before the clinical onset; they involve the parietal region primarily and then spread to the anterior regions of the brain, supporting the concept of molecular nexopathies.     

Infectivity of DWV Associated to Flower Pollen: Experimental Evidence of a Horizontal Transmission Route

Deformed wing virus (DWV) is a honeybee pathogen whose presence is generally associated with infestation of the colony by the mite Varroa destructor, leading to the onset of infections responsible for the collapse of the bee colony. DWV contaminates bee products such as royal jelly, bee-bread and honey stored within the infected hive. Outside the hive, DWV has been found in pollen loads collected directly from infected as well as uninfected forager bees. It has been shown that the introduction of virus-contaminated pollen into a DWV-free hive results in the production of virus-contaminated food, whose role in the development of infected bees from virus-free eggs has been experimentally demonstrated. The aim of this study was twofold: (i) to ascertain the presence of DWV on pollen collected directly from flowers visited by honeybees and then quantify the viral load and (ii) determine whether the virus associated with pollen is infective. The results of our investigation provide evidence that DWV is present on pollen sampled directly from visited flowers and that, following injection in individuals belonging to the pollinator species Apis mellifera, it is able to establish an active infection, as indicated by the presence of replicating virus in the head of the injected bees. We also provide the first indication that the pollinator species Osmia cornuta is susceptible to DWV infection.     

Structure of an engineered intein reveals thiazoline ring and provides mechanistic insight

We have engineered an intein which spontaneously and reversibly forms a thiazoline ring at the native N-terminal Lys-Cys splice junction. We identified conditions to stablize the thiazoline ring and provided the first crystallographic evidence, at 1.54 Å resolution, for its existence at an intein active site. The finding bolsters evidence for a tetrahedral oxythiazolidine splicing intermediate. In addition, the pivotal mutation maps to a highly conserved B-block threonine, which is now seen to play a causative role not only in ground-state destabilization of the scissile N-terminal peptide bond, but also in steering the tetrahedral intermediate toward thioester formation, giving new insight into the splicing mechanism. We demonstrated the stability of the thiazoline ring at neutral pH as well as sensitivity to hydrolytic ring opening under acidic conditions. A pH cycling strategy to control N-terminal cleavage is proposed, which may be of interest for biotechnological applications requiring a splicing activity switch, such as for protein recovery in bioprocessing.     

Aspergillus tubingensis Endocarditis: A Case Report and Review of the Literature

Mycopathologia - Aspergillus endocarditis is a rare infection that may affect immunocompetent patients following heart valve replacement or heart surgery. We report the case of a 39 year...     

Are atopy and eosinophilic bronchial inflammation associated with relapsing forms of chronic rhinosinusitis with nasal polyps?

Background

The aetiopathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) is still unknown. The role of atopy and the concept of united airways in such patients are still a matter of debate. In this pilot study we aimed at evaluating the degree of eosinophilic inflammation and the frequency of atopy in a cohort of CRSwNP patients candidate for Functional Endoscopic Sinus Surgery (FESS) and assessing the association between these factors and relapsing forms of CRSwNP.

Methods

30 patients (18 men, 12 women) with CRSwNP eligible for FESS were evaluated before and after surgery. Preoperative investigation included: history of previous relapse after FESS, clinical and laboratory allergologic assessment, spirometry, methacholine challenge, blood eosinophilia and determination of the fraction of nitric oxide in exhaled air (FeNO). Nasal fibroendoscopy, spirometry and FeNO determination were also assessed prospectively at 3 and 27 months post-FESS.

Results

18/30 subjects were atopic, 6/18 (33 %) were monosensitized, 16/30 (53 %) were asthmatics and 10/30 (33 %) had non steroidalantinflammatory drugs (NSAIDs) hypersensitivity. Twenty-one patients (70 %) were classified as relapsers, 15/18 (83 %) among atopics, 6/12 (50 %) among non atopics (p = 0.05). Among patients with NSAIDs hypersensitivity, 9/10 (90 %) were relapsers. The median IgE concentration was 161.5 UI/mL in relapsers and 79 UI/mL in non-relapsers (ns). The mean FeNO decreased after FESS (43.1–26.6 ppb) in 84 % of patients, but this effect disappeared over time (FeNO = 37.7 ppb at 27 months). Higher levels of FeNO pre-FESS were detected in atopics, and in particular in relapsing ones (median 51.1 ppb vs 22.1, ns). Higher levels of FeNO pre-FESS were detected in asthmatic patients, especially in those who relapsed (median: 67 vs 64.85 ppb in non-relapsed patients, ns). The Tiffeneau Index (FEV1/FVC) was significantly lower in asthmatic relapsers than in non relapsers asthmatics (94.7 ± 11.1 versus 105 ± 5.9—p = 0.04). Patients with asthma and atopy had a major risk of relapse (p = 0.05).

Conclusion

In our pilot study, atopy, severe asthma, bronchial inflammation, NSAIDs hypersensitivity and high level of total IgE are possible useful prognostic factors for the proneness to relapse after FESS. The role of allergy in CRSwNP pathogenesis should consequently be given deeper consideration. Allergen specific immunotherapy, combined with anti-IgE therapy, may have an immunomodulatory effect preventing polyps relapse and need to be investigated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12948-015-0026-8) contains supplementary material, which is available to authorized users.     

Unraveling interactions of cell cycle-regulating proteins Sic1 and B-type cyclins in living yeast cells: a FLIM-FRET approach

Sic1, cyclin-dependent kinase inhibitor of budding yeast, is synthesized in anaphase and largely degraded at the S-phase onset to regulate timing of DNA synthesis. Sic1 interacts with phase-specific B-type cyclin (Clb)-kinase (Cdk1) complexes, central regulators in cell cycle control. Its appearance is timed to mediate reduction in kinase activities at appropriate stages. Clbs are unstable proteins with extremely short half-lives. Interactions of Sic1 with Clbs have been detected both in vitro and in vivo by high-throughput genome-wide screenings. Furthermore, we have recently shown that Sic1 regulates waves of Clbs, acting as a timer in their appearance, thus controlling Cdk1-Clbs activation. The molecular mechanism is not yet fully understood but is hypothesized to occur via stoichiometric binding of Sic1 to Cdk1-Clb complexes. Using F?rster resonance energy transfer (FRET) via fluorescence lifetime imaging microscopy (FLIM), we showed association of Sic1 to Clb cyclins in living yeast cells. This finding is consistent with the notion that inhibition of kinase activity can occur over the whole cell cycle progression despite variable Sic1 levels. Specifically, Sic1/Clb3 interaction was observed for the first time, and Sic1/Clb2 and Sic1/Clb5 pairs were confirmed, but no Sic1/Clb4 interaction was found, which suggests that, despite high functional homology between Clbs, only some of them can target Sic1 function in vivo.     

Targeting TNF-α to neoangiogenic vessels enhances lymphocyte infiltration in tumors and increases the therapeutic potential of immunotherapy

Abnormal tumor vasculature impairs T lymphocyte adhesion to endothelial cells and lymphocyte extravasation into neoplastic tissues, limiting the therapeutic potential of both active and adoptive immunotherapies. We have found that treatment of tumor-bearing mice with NGR-TNF, a Cys-Asn-Gly-Arg-Cys peptide-TNF fusion product capable of altering the endothelial barrier function and improving drug penetration in tumors, associated with the intratumor upregulation of leukocyte-endothelial cell adhesion molecules, the release of proinflammatory cytokines and chemokines, and the infiltration of tumor-specific effector CD8(+) T cells. As a result, NGR-TNF enhanced the therapeutic activity of adoptive and active immunotherapy, delaying tumor growth and prolonging survival. Furthermore, we have found that therapeutic effects of these combinations can be further increased by the addition of chemotherapy. Thus, these findings might be relevant for the design of novel immunotherapeutic approaches for cancer patients.     

The Changes of Lipid Metabolism in Advanced Renal Cell Carcinoma Patients Treated with Everolimus: A New Pharmacodynamic Marker?

Background

Everolimus is a mammalian target of rapamycin (mTOR) inhibitor approved for the treatment of metastatic renal cell carcinoma (mRCC). We aimed to assess the association between the baseline values and treatmentrelated modifications of total serum cholesterol (C), triglycerides (T), body mass index (BMI), fasting blood glucose level (FBG) and blood pressure (BP) levels and the outcome of patients treated with everolimus for mRCC.

Methods

177 patients were included in this retrospective analysis. Time to progression (TTP), clinical benefit (CB) and overall survival (OS) were evaluated.

Results

Basal BMI was significantly higher in patients who experienced a CB (p=0,0145). C,T and C+T raises were significantly associated with baseline BMI (p=0.0412, 0.0283 and 0.0001). Median TTP was significantly longer in patients with T raise compared to patients without T (10 vs 6, p=0.030), C (8 vs 5, p=0.042) and C+T raise (10.9 vs 5.0, p=0.003). At the multivariate analysis, only C+T increase was associated with improved TTP (p=0.005). T raise (21.0 vs 14.0, p=0.002) and C+T increase (21.0 vs 14.0, p=0.006) were correlated with improved OS but were not significant at multivariate analysis.

Conclusion

C+T raise is an early predictor for everolimus efficacy for patients with mRCC.     

Multiple imputation methods for handling incomplete longitudinal and clustered data where the target analysis is a linear mixed effects model

Multiple imputation (MI) is increasingly popular for handling multivariate missing data. Two general approaches are available in standard computer packages: MI based on the posterior distribution of incomplete variables under a multivariate (joint) model, and fully conditional specification (FCS), which imputes missing values using univariate conditional distributions for each incomplete variable given all the others, cycling iteratively through the univariate imputation models. In the context of longitudinal or clustered data, it is not clear whether these approaches result in consistent estimates of regression coefficient and variance component parameters when the analysis model of interest is a linear mixed effects model (LMM) that includes both random intercepts and slopes with either covariates or both covariates and outcome contain missing information. In the current paper, we compared the performance of seven different MI methods for handling missing values in longitudinal and clustered data in the context of fitting LMMs with both random intercepts and slopes. We study the theoretical compatibility between specific imputation models fitted under each of these approaches and the LMM, and also conduct simulation studies in both the longitudinal and clustered data settings. Simulations were motivated by analyses of the association between body mass index (BMI) and quality of life (QoL) in the Longitudinal Study of Australian Children (LSAC). Our findings showed that the relative performance of MI methods vary according to whether the incomplete covariate has fixed or random effects and whether there is missingnesss in the outcome variable. We showed that compatible imputation and analysis models resulted in consistent estimation of both regression parameters and variance components via simulation. We illustrate our findings with the analysis of LSAC data.