Mitochondrial Ca2+ signalling in hippocampal neurons

High-resolution fluorescent imaging of mitochondrial-targeted probes was used to examine the ability of mitochondria to decode complex spatial and temporal Ca2+ signals evoked in synaptically active networks of hippocampal neurons. Green-to-red photoconversion of the mitochondrial-targeted probe, mito-Kaede, demonstrated that mitochondria were present as discrete organelles 2-6 microm in length. Real-time imaging of mitochondrial-targeted ratiometric pericam (2 mtRP) visualised rapid, repetitive, transient mitochondrial Ca2+ fluxes in response to periods of synaptic activation. Mitochondrial Ca2+ fluxes within cellular compartments were dependent on the extent of synaptic recruitment, but independent of cross-talk with the endoplasmic reticulum or the presence of an interconnected mitochondrial network. Mitochondria in dendritic regions demonstrated a greater sensitivity to synaptic activation compared with somatic mitochondria. Temporal decoding of synaptic signals was rate-limited by the activity of the mitochondrial Na+/Ca2+ exchanger. Spatial regulation of mitochondrial Ca2+ uptake was determined by the magnitude of the cytosolic Ca2+ rise in each cellular compartment.     

Flexible nonlinear blind signal separation in the complex domain

This paper introduces an Independent Component Analysis (ICA) approach to the separation of nonlinear mixtures in the complex domain. Source separation is performed by a complex INFOMAX approach. The neural network which realizes the separation employs the so called "Mirror Model" and is based on adaptive activation functions, whose shape is properly modified during learning. Nonlinear functions involved in the processing of complex signals are realized by pairs of spline neurons called "splitting functions", working on the real and the imaginary part of the signal respectively. Theoretical proof of existence and uniqueness of the solution under proper assumptions is also provided. In particular a simple adaptation algorithm is derived and some experimental results that demonstrate the effectiveness of the proposed solution are shown.     

Potential Role of IL-17-Producing iNKT Cells in Type 1 Diabetes

We explored in this study the status and potential role of IL-17-producing iNKT cells (iNKT17) in type 1 diabetes (T1D) by analyzing these cells in patients with T1D, and in NOD mice, a mouse model for T1D. Our analysis in mice showed an increase of iNKT17 cells in NOD vs control C57BL/6 mice, partly due to a better survival of these cells in the periphery. We also found a higher frequency of these cells in autoimmune-targeted organs with the occurrence of diabetes, suggesting their implication in the disease development. In humans, though absent in fresh PMBCs, iNKT17 cells are detected in vitro with a higher frequency in T1D patients compared to control subjects in the presence of the proinflammatory cytokine IL-1β, known to contribute to diabetes occurrence. These IL-1β-stimulated iNKT cells from T1D patients keep their potential to produce IFN-γ, a cytokine that drives islet β-cell destruction, but not IL-4, with a reverse picture observed in healthy volunteers. On the whole, our results argue in favour of a potential role of IL-17-producing iNKT cells in T1D and suggest that inflammation in T1D patients could induce a Th1/Th17 cytokine secretion profile in iNKT cells promoting disease development.     

Trypanocidal Activity of Dysphania ambrosioides,Lippia alba,and Tetradenia riparia Essential Oils against Trypanosoma cruzi

Despite the current treatments against Chagas Disease (CD), this vector-borne parasitic disease remains a serious public health concern. In this study, we have explored the in vitro and/or in vivo trypanocidal and cytotoxic activities of the essential oils (EOs) obtained from Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) (DA-EO), Lippia alba (Mill.) N.E. Brown (Verbenaceae) (LA-EO), and Tetradenia riparia (Hochst.) Codd (Lamiaceae) (TR-EO) grown in Brazil Southeast. DA-EO was the most active against the trypomastigote and amastigote forms in vitro; the IC₅₀ values were 8.7 and 12.2 μg mL⁻¹, respectively. The EOs displayed moderate toxicity against LLCMK2 cells, but the DA-EO showed high selectivity index (SI) for trypomastigote (SI=33.2) and amastigote (SI=11.7) forms. Treatment with 20 mg/kg DA-EO, LA-EO, or TR-EO for 20 days by intraperitoneal administration reduced parasitemia by 6.36 %, 4.74 %, and 32.68 % on day 7 and by 12.04 %, 27.96 %, and 65.5 % on day 9. These results indicated that DA-EO, LA-EO, and TR-EO have promising trypanocidal potential in vitro, whereas TR-EO has also potential trypanocidal effects in vivo.     

Identification of NF-κB and PLCL2 as new susceptibility genes and highlights on a potential role of IRF8 through interferon signature modulation in systemic sclerosis

IntroductionSystemic sclerosis (SSc) and primary biliary cirrhosis (PBC) are rare polygenic autoimmune diseases (AIDs) characterized by fibroblast dysfunction. Furthermore, both diseases share some genetic bases with other AIDs, as evidenced by autoimmune gene pleiotropism. The present study was undertaken to investigate whether single-nucleotide polymorphisms (SNPs) identified by a large genome-wide association study (GWAS) in PBC might contribute to SSc susceptibility.MethodsSixteen PBC susceptibility SNPs were genotyped in a total of 1,616 patients with SSc and 3,621 healthy controls from two European populations (France and Italy).ResultsWe observed an association between PLCL2 rs1372072 (odds ratio (OR) = 1.22, 95% confidence interval (CI) 1.12 to 1.33, P_adj = 7.22 × 10⁻⁵), nuclear factor-kappa-B (NF-κB) rs7665090 (OR = 1.15, 95% CI 1.06 to 1.25, P_adj = 0.01), and IRF8 rs11117432 (OR = 0.75, 95% CI 0.67 to 0.86, P_adj = 2.49 × 10⁻⁴) with SSc susceptibility. Furthermore, phenotype stratification showed an association between rs1372072 and rs11117432 with the limited cutaneous subgroup (lcSSc) (P_adj = 4.45 × 10⁻⁴ and P_adj = 0.001), whereas rs7665090 was associated with the diffuse cutaneous subtype (dcSSc) (P_adj = 0.003). Genotype-mRNA expression correlation analysis revealed that the IRF8 protective allele was associated with increased interferon-gamma (IFN-γ) expression (P = 0.03) in patients with SSc but decreased type I IFN (IFIT1) expression in patients and controls (P = 0.02). In addition, we found an epistatic interaction between NF-κB and IRF8 (OR = 0.56, 95% CI 0.00 to 0.74, P = 4 × 10⁻⁴) which in turn revealed that the IRF8 protective effect is dependent on the presence of the NF-κB susceptibility allele.ConclusionsAn analysis of pleiotropic genes identified two new susceptibility genes for SSc (NF-κB and PLCL2) and confirmed the IRF8 locus. Furthermore, the IRF8 variant influenced the IFN signature, and we found an interaction between IRF8 and NF-κB gene variants that might play a role in SSc susceptibility.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0572-y) contains supplementary material, which is available to authorized users.     

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.     

Extensive activation,tissue trafficking,turnover and functional impairment of NK cells in COVID-19 patients at disease onset associates with subsequent disease severity

The SARS-CoV-2 infection causes severe respiratory involvement (COVID-19) in 5–20% of patients through initial immune derangement, followed by intense cytokine production and vascular leakage. Evidence of immune involvement point to the participation of T, B, and NK cells in the lack of control of virus replication leading to COVID-19. NK cells contribute to early phases of virus control and to the regulation of adaptive responses. The precise mechanism of NK cell dysregulation is poorly understood, with little information on tissue margination or turnover. We investigated these aspects by multiparameter flow cytometry in a cohort of 28 patients hospitalized with early COVID-19.Relevant decreases in CD56^brightCD16+/- NK subsets were detected, with a shift of circulating NK cells toward more mature CD56^dimCD16+KIR+NKG2A+ and “memory” KIR+CD57+CD85j+ cells with increased inhibitory NKG2A and KIR molecules. Impaired cytotoxicity and IFN-γ production were associated with conserved expression of natural cytotoxicity receptors and perforin. Moreover, intense NK cell activation with increased HLA-DR and CD69 expression was associated with the circulation of CD69+CD103+ CXCR6+ tissue-resident NK cells and of CD34+DNAM-1^brightCXCR4+ inflammatory precursors to mature functional NK cells. Severe disease trajectories were directly associated with the proportion of CD34+DNAM-1^brightCXCR4+ precursors and inversely associated with the proportion of NKG2D+ and of CD103+ NK cells.Intense NK cell activation and trafficking to and from tissues occurs early in COVID-19, and is associated with subsequent disease progression, providing an insight into the mechanism of clinical deterioration. Strategies to positively manipulate tissue-resident NK cell responses may provide advantages to future therapeutic and vaccine approaches.