Acceleration waves and oscillating gas bubbles modelled by rational extended thermodynamics

The study of acceleration waves for a rarefied polyatomic gas is carried out in planar, cylindrical and spherical geometry referring to the rational extended thermodynamics theory with 14 moments. The case of a rarefied monatomic gas is determined as a limit case, and the role of geometry and molecular degrees of freedom is investigated. In addition, the behaviour of an acceleration wave travelling inside an oscillating gas bubble is modelled by the 14-moment PDE system under adiabatic condition. We show that dissipation combined with hyperbolicity tends to inhibit shock formation, and that the dynamic pressure cannot be zero inside the oscillating bubble. This fact can produce observable effects even in the Navier–Stokes approximation, if the gas exhibits high bulk viscosity

Drug Loaded Gingival Mesenchymal Stromal Cells (GinPa-MSCs) Inhibit In Vitro Proliferation of Oral Squamous Cell Carcinoma

Human mesenchymal stromal cells (MSCs) have been widely investigated both for regenerative medicine and their antinflammatory/immunomodulatory capacity. However, their ability to home pathological tissues suggested the development of strategies for using MSCs as carrier to deliver drug into tumor microenvironment. MSCs obtained from different tissues can be loaded in vitro with anti-cancer drugs by a simple procedures. In this report, we studied MSCs isolated and expanded from gingival papilla (GinPa-MSCs), by testing their ability to uptake and release three important anti-neoplastic drugs: Paclitaxel (PTX), Doxorubicin (DXR) and Gemcitabine (GCB). The efficacy of drugs releasing GinPa-MSCs was studied on a pancreatic cancer cell line and confirmed in vitro against a line of tongue squamous cell carcinoma (SCC154). Our results demonstrated that GinPa-MSCs efficiently incorporate the drugs and then released them in active form and in sufficient amount to produce a dramatic inhibition of squamous cell carcinoma growth in vitro. If compared with other MSCs sources, the collection of GinPa-MSCs is poorly invasive and cells can be easily expanded and efficiently loaded with anti cancer drugs. In particular, gemcitabine loaded GinPa-MSCs provide a good "cell-mediated drug delivery system" for a future potential application in the context of the oral oncology

SPLICS: a split green fluorescent protein-based contact site sensor for narrow and wide heterotypic organelle juxtaposition

Contact sites are discrete areas of organelle proximity that coordinate essential physiological processes across membranes, including Ca2+ signaling, lipid biosynthesis, apoptosis, and autophagy. However, tools to easily image inter-organelle proximity over a range of distances in living cells and in vivo are lacking. Here we report a split-GFP-based contact site sensor (SPLICS) engineered to fluoresce when organelles are in proximity. Two SPLICS versions efficiently measured narrow (8\u201310 nm) and wide (40\u201350 nm) juxtapositions between endoplasmic reticulum and mitochondria, documenting the existence of at least two types of contact sites in human cells. Narrow and wide ER\u2013mitochondria contact sites responded differently to starvation, ER stress, mitochondrial shape modifications, and changes in the levels of modulators of ER\u2013mitochondria juxtaposition. SPLICS detected contact sites in soma and axons of D. rerio Rohon Beard (RB) sensory neurons in vivo, extending its use to analyses of organelle juxtaposition in the whole anim

Tau localises within mitochondrial sub-compartments and its caspase cleavage affects ER-mitochondria interactions and cellular Ca2+ handling

Intracellular neurofibrillary tangles (NFT) composed by tau and extracellular amyloid beta (A\u3b2) plaques accumulate in Alzheimer's disease (AD) and contribute to neuronal dysfunction. Mitochondrial dysfunction and neurodegeneration are increasingly considered two faces of the same coin and an early pathological event in AD. Compelling evidence indicates that tau and mitochondria are closely linked and suggests that tau-dependent modulation of mitochondrial functions might be a trigger for the neurodegeneration process; however, whether this occurs either directly or indirectly is not clear. Furthermore, whether tau influences cellular Ca2+ handling and ER-mitochondria cross-talk is yet to be explored. Here, by focusing on wt tau, either full-length (2N4R) or the caspase 3-cleaved form truncated at the C-terminus (2N4R\u394C20), we examined the above-mentioned aspects. Using new genetically encoded split-GFP-based tools and organelle-targeted aequorin probes, we assessed: i) tau distribution within the mitochondrial sub-compartments; ii) the effect of tau on the short- (8-10\u202fnm) and the long- (40-50\u202fnm) range ER-mitochondria interactions; and iii) the effect of tau on cytosolic, ER and mitochondrial Ca2+ homeostasis. Our results indicate that a fraction of tau is found at the outer mitochondrial membrane (OMM) and within the inner mitochondrial space (IMS), suggesting a potential tau-dependent regulation of mitochondrial functions. The ER Ca2+ content and the short-range ER-mitochondria interactions were selectively affected by the expression of the caspase 3-cleaved 2N4R\u394C20 tau, indicating that Ca2+ mis-handling and defects in the ER-mitochondria communications might be an important pathological event in tau-related dysfunction and thereby contributing to neurodegeneration. Finally, our data provide new insights into the molecular mechanisms underlying tauopathies

Interaction Between Dietary Lipid Level and Seasonal Temperature Changes in Gilthead Sea Bream Sparus aurata: Effects on Growth, Fat Deposition, Plasma Biochemistry, Digestive Enzyme Activity, and Gut Bacterial Community

A 121-day feeding trial was undertaken to test the effects of two dietary lipid levels (16 and 21% L16, L21) in triplicated gilthead sea bream groups (initial weight: 67.5 g) reared at two different water temperatures (high, H 23°C and low, L 17°C) in the same recirculation system but exposed to a switch in temperature after 58 days. Fish kept at H were transferred to L (HL transition, autumn shift), and the fish kept at L were exposed to H (LH transition, summer shift), while continuing to receive the same diet to apparent satiation in each group. At the end of the trial, no significant diet effect on specific growth rate (SGR), feed intake (FI), and feed conversion rate (FCR) were detected in fish exposed to HL transition compared with those exposed to LH transition, while gross lipid efficiency (GLE) and lipid efficiency ratio (LER) were higher in L16. After temperature changes, L16 displayed higher SGR, FI, GLE, and LER, while mesenteric fat index was reduced. After temperature changes, the combined effects of low lipid diet and low temperature conditions resulted in higher pepsin activity, while trypsin, chymotrypsin, and lipase activities were generally higher at high lipid content. The combined effect of diet and temperature did not alter the metabolic plasma profile, except for the observed final higher aspartate aminotransferase (AST) and alkaline phosphatase (ALP) values when combining high dietary lipid (L21) and temperature changes. Different diets showed a significantly different gut microbiome layout, only at high temperature with L16 diet resulting in a higher load of Lactobacillus. On the contrary, no dietary impact on ecosystem diversity was observed, independently from the temperature. In addition, L16 diet in the HL transition favored an increase in Weissella and Bradyrhizobium genera in the gut microbiome, while in the final condition of LH transition, L21 diet favored a significant increase in Streptococcus and Bacillus. According to the results, the utilization of 16% dietary lipid levels in gilthead sea bream should be preferred during seasonal temperature changes in order to optimize feed utilization and gut health.This research was undertaken under the MedAID (Mediterranean Aquaculture Integrated Development) project, which has received funding from the European Union’s Horizon 2020 Research and Innovation Programme, Call H2020-SFS-23-2016, Grant agreement no. 727315 (http://www.medaid-h2020.eu/). MY and NG received support from the Spanish Ministry of Science, Innovation and Universities (MCIU), the State Research Agency (AEI), the European Regional Development Fund (FEDER/ERDF), and project Thermodigest (RTI2018-096134-B-I00) granted to MY

Cutting edge: IgE plays an active role in tumor immunosurveillance in mice

Exogenous IgE acts as an adjuvant in tumor vaccination in mice, and therefore a direct role of endogenous IgE in tumor immunosurveillance was investigated. By using genetically engineered mice, we found that IgE ablation rendered mice more susceptible to the growth of transplantable tumors. Conversely, a strengthened IgE response provided mice with partial or complete resistance to tumor growth, depending on the tumor type. By genetic crosses, we showed that IgE-mediated tumor protection was mostly lost in mice lacking FceRI. Tumor protection was also lost after depletion of CD8+ T cells, highlighting a cross-Talk between IgE and T cell- mediated tumor immunosurveillance. Our findings provide the rationale for clinical observations that relate atopy with a lower risk for developing cancer and open new avenues for the design of immunotherapeutics relevant for clinical oncology. The Journal of Immunology, 2016, 197: 2583-2588

Dysregulation of MS risk genes and pathways at distinct stages of disease

OBJECTIVE: To perform systematic transcriptomic analysis of multiple sclerosis (MS) risk genes in peripheral blood mononuclear cells (PBMCs) of subjects with distinct MS stages and describe the pathways characterized by dysregulated gene expressions. METHODS: We monitored gene expression levels in PBMCs from 3 independent cohorts for a total of 297 cases (including clinically isolated syndromes (CIS), relapsing-remitting MS, primary and secondary progressive MS) and 96 healthy controls by distinct microarray platforms and quantitative PCR. Differential expression and pathway analyses for distinct MS stages were defined and validated by literature mining. RESULTS: Genes located in the vicinity of MS risk variants displayed altered expression in peripheral blood at distinct stages of MS compared with the healthy population. The frequency of dysregulation was significantly higher than expected in CIS and progressive forms of MS. Pathway analysis for each MS stage–specific gene list showed that dysregulated genes contributed to pathogenic processes with scientific evidence in MS. CONCLUSIONS: Systematic gene expression analysis in PBMCs highlighted selective dysregulation of MS susceptibility genes playing a role in novel and well-known pathogenic pathways

Monitoring calcium handling by the plant endoplasmic reticulum with a low‐Ca 2+ ‐affinity targeted aequorin reporter

Precise measurements of dynamic changes in free Ca2+ concentration in the lumen of the plant endoplasmic reticulum (ER) have been lacking so far, despite increasing evidence for the contribution of this intracellular compartment to Ca2+ homeostasis and signalling in the plant cell. In the present study, we targeted an aequorin chimera with reduced Ca2+ affinity to the ER membrane and facing the ER lumen. To this aim, the cDNA for a low-Ca2+-affinity aequorin variant (AEQmut) was fused to the nucleotide sequence encoding a non-cleavable N-terminal ER signal peptide (fl2). The correct targeting of fl2-AEQmut was confirmed by immunocytochemical analyses in transgenic Arabidopsis thaliana (Arabidopsis) seedlings. An experimental protocol well-established in animal cells – consisting of ER Ca2+ depletion during photoprotein reconstitution followed by ER Ca2+ refilling – was applied to carry out ER Ca2+ measurements in planta. Rapid and transient increases of the ER luminal Ca2+ concentration ([Ca2+]ER) were recorded in response to different environmental stresses, displaying stimulus-specific Ca2+ signatures. The comparative analysis of ER and chloroplast Ca2+ dynamics indicates a complex interplay of these organelles in shaping cytosolic Ca2+ signals during signal transduction events. Our data highlight significant differences in basal [Ca2+]ER and Ca2+ handling by plant ER compared to the animal counterpart. The set-up of an ER-targeted aequorin chimera extends and complements the currently available toolkit of organelle-targeted Ca2+ indicators by adding a reporter that improves our quantitative understanding of Ca2+ homeostasis in the plant endomembrane system

The Novel Mouse Mutation Oblivion Inactivates the PMCA2 Pump and Causes Progressive Hearing Loss

Progressive hearing loss is common in the human population, but we have few clues to the molecular basis. Mouse mutants with progressive hearing loss offer valuable insights, and ENU (N-ethyl-N-nitrosourea) mutagenesis is a useful way of generating models. We have characterised a new ENU-induced mouse mutant, Oblivion (allele symbol Obl), showing semi-dominant inheritance of hearing impairment. Obl/+ mutants showed increasing hearing impairment from post-natal day (P)20 to P90, and loss of auditory function was followed by a corresponding base to apex progression of hair cell degeneration. Obl/Obl mutants were small, showed severe vestibular dysfunction by 2 weeks of age, and were completely deaf from birth; sensory hair cells were completely degenerate in the basal turn of the cochlea, although hair cells appeared normal in the apex. We mapped the mutation to Chromosome 6. Mutation analysis of Atp2b2 showed a missense mutation (2630C→T) in exon 15, causing a serine to phenylalanine substitution (S877F) in transmembrane domain 6 of the PMCA2 pump, the resident Ca2+ pump of hair cell stereocilia. Transmembrane domain mutations in these pumps generally are believed to be incompatible with normal targeting of the protein to the plasma membrane. However, analyses of hair cells in cultured utricular maculae of Obl/Obl mice and of the mutant Obl pump in model cells showed that the protein was correctly targeted to the plasma membrane. Biochemical and biophysical characterisation showed that the pump had lost a significant portion of its non-stimulated Ca2+ exporting ability. These findings can explain the progressive loss of auditory function, and indicate the limits in our ability to predict mechanism from sequence alone

Impaired Mitochondrial ATP Production Downregulates Wnt Signaling via ER Stress Induction.

Wnt signaling affects fundamental development pathways and, if aberrantly activated, promotes the development of cancers. Wnt signaling is modulated by different factors, but whether the mitochondrial energetic state affects Wnt signaling is unknown. Here, we show that sublethal concentrations of different compounds that decrease mitochondrial ATP production specifically downregulate Wnt/β-catenin signaling in vitro in colon cancer cells and in vivo in zebrafish reporter lines. Accordingly, fibroblasts from a GRACILE syndrome patient and a generated zebrafish model lead to reduced Wnt signaling. We identify a mitochondria-Wnt signaling axis whereby a decrease in mitochondrial ATP reduces calcium uptake into the endoplasmic reticulum (ER), leading to endoplasmic reticulum stress and to impaired Wnt signaling. In turn, the recovery of the ATP level or the inhibition of endoplasmic reticulum stress restores Wnt activity. These findings reveal a mechanism that links mitochondrial energetic metabolism to the control of the Wnt pathway that may be beneficial against several pathologies