Vanadium Inhalation in a Mouse Model for the Understanding of Air-Suspended Particle Systemic Repercussion

There is an increased concern about the health effects that air-suspended particles have on human health which have been dissected in animal models. Using CD-1 mouse, we explore the effects that vanadium inhalation produce in different tissues and organs. Our findings support the systemic effects of air pollution. In this paper, we describe our findings in different organs in our conditions and contrast our results with the literature

Polarized secretion of Leukemia Inhibitory Factor

<p>Abstract</p> <p>Background</p> <p>The direction of cytokine secretion from polarized cells determines the cytokine's cellular targets. Leukemia inhibitory factor (LIF) belongs to the interleukin-6 (IL-6) family of cytokines and signals through LIFR/gp130. Three factors which may regulate the direction of LIF secretion were studied: the site of stimulation, signal peptides, and expression levels. Stimulation with IL-1β is known to promote IL-6 secretion from the stimulated membrane (apical or basolateral) in the human intestinal epithelial cell line Caco-2. Since LIF is related to IL-6, LIF secretion was also tested in Caco-2 following IL-1β stimulation. Signal peptides may influence the trafficking of LIF. Two isoforms of murine LIF, LIF-M and LIF-D, encode different signal peptides which have been associated with different locations of the mature protein in fibroblasts. To determine the effect of the signal peptides on LIF secretion, secretion levels were compared in Madin-Darby canine kidney (MDCK) clones which expressed murine LIF-M or LIF-D or human LIF under the control of an inducible promoter. Low and high levels of LIF expression were also compared since saturation of the apical or basolateral route would reveal specific transporters for LIF.</p> <p>Results</p> <p>When Caco-2 was grown on permeable supports, LIF was secreted constitutively with around 40% secreted into the apical chamber. Stimulation with IL-1β increased LIF production. After treating the apical surface with IL-1β, the percentage secreted apically remained similar to the untreated, whereas, when the cells were stimulated at the basolateral surface only 20% was secreted apically. In MDCK cells, an endogenous LIF-like protein was detected entirely in the apical compartment. The two mLIF isoforms showed no difference in their secretion patterns in MDCK. Interestingly, about 70% of murine and human LIF was secreted apically from MDCK over a 400-fold range of expression levels within clones and a 200,000-fold range across clones.</p> <p>Conclusion</p> <p>The site of stimulation affected the polarity of LIF secretion, while, signal peptides and expression levels did not. Exogenous LIF is transported in MDCK without readily saturated steps.</p

Insulin Storage and Glucose Homeostasis in Mice Null for the Granule Zinc Transporter ZnT8 and Studies of the Type 2 Diabetes–Associated Variants

International audienceObjective. Zinc ions are essential for the formation of hexameric insulin and hormone crystallisation. Correspondingly, a non-synonymous single nucleotide polymorphism rs13266634 in the SLC30A8 gene, encoding the secretory granule zinc transporter ZnT8, is associated with type 2 diabetes. Here, we describe the effects of deleting the ZnT8 gene in mice and explore the action of the at-risk allele. Research Design and Methods. Slc30a8 null mice were generated and backcrossed at least twice onto a C57BL/6J background. Glucose and insulin tolerance were measured by intraperitoneal injection, or euglycemic clamp, respectively. Insulin secretion, electrophysiology, imaging, and the generation of adenoviruses encoding the low- (W325) or elevated- (R325) risk ZnT8 alleles, were undertaken using standard protocols. Results. ZnT8(-/-) mice displayed age, sex and diet-dependent abnormalities in glucose tolerance, insulin secretion and body weight. Islets isolated from null mice had reduced granule zinc content, and showed age-dependent changes in granule morphology, with markedly fewer dense cores but more rod-like crystals. Glucose-stimulated insulin secretion, granule fusion and insulin crystal dissolution, as assessed by total internal reflection fluorescence microscopy, were unchanged or enhanced in ZnT8(-/-) islets. Insulin processing was normal. Molecular modelling revealed that residue-325 was located at the interface between ZnT8 monomers. Correspondingly, the R325 variant displayed lower apparent Zn(2+) transport activity than W325 ZnT8 by fluorescence-based assay. Discussion and conclusions. ZnT8 is required for normal insulin crystallisation and insulin release in vivo but not, remarkably, in vitro. Defects in the former processes in carriers of the R allele may increase type 2 diabetes risk

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Impaired cleavage of preproinsulin signal peptide linked to autosomal-dominant diabetes

Recently, missense mutations upstream of preproinsulin's signal peptide (SP) cleavage site were reported to cause mutant INS gene-induced diabetes of youth (MIDY). To understand the molecular pathogenesis, our objective was to use metabolic labeling and assays of proinsulin export and insulin and C-peptide production to examine the earliest events of insulin biosynthesis, highlighting molecular mechanisms underlying β-cell failure, plus a novel strategy that might ameliorate the MIDY syndrome. We find that whereas preproinsulin-A(SP23)S is efficiently cleaved, producing authentic proinsulin and insulin, preproinsulin-A(SP24)D is inefficiently cleaved at an improper site, producing two subpopulations of molecules. Both show impaired oxidative folding and are retained in the endoplasmic reticulum (ER). Preproinsulin-A(SP24)D also blocks ER exit of coexpressed wild-type proinsulin, accounting for its dominant-negative behavior. Upon increased expression of ER-oxidoreductin-1, preproinsulin-A(SP24)D remains blocked but oxidative folding of wild-type proinsulin improves, accelerating its ER export and increasing wild-type insulin production. We conclude that the efficiency of SP cleavage is linked to the oxidation of (pre)proinsulin. In turn, impaired (pre)proinsulin oxidation affects ER export of the mutant as well as that of coexpressed wild-type proinsulin. Improving oxidative folding of wild-type proinsulin may provide a feasible way to rescue insulin production in patients with MIDY

Amaranto BRS Alegria: alternativa para diversificar os sistemas de produção Amaranth BRS Alegria: alternative for diversification of cropping systems

A diversificação do sistema produtivo depende de espécies com rápido crescimento, tolerância ao déficit hídrico, produção de biomassa, ciclagem de nutrientes e utilização humana e animal. As espécies Amaranthus caudatus, A. cruentus e A. hypochondriacus apresentam essas características e sementes claras, sem dormência. Distinguem-se das invasoras A. spinosus, A. hybridus, A. blitum e A. viridis, com sementes escuras e dormentes. Os grãos, com excelente qualidade protéica, atendem à demanda por dietas especiais, livres de glúten e podem ser usados na alimentação animal. O A. cruentus BRS Alegria, primeira recomendação ao cultivo granífero no Brasil, originou-se da variedade AM 5189, dos Estados Unidos, na qual realizou-se seleção massal. Em sucessão à soja, apresentou produção média de 2.359 kg ha-1 de grãos e 5.650 kg ha-1 de biomassa total em apenas 90 dias de ciclo.<br>Diversification of production systems depends on rapid growth, tolerance to hydric stress, biomass production, nutrient cycling and human and animal utilization. The grain amaranth species Amaranthus caudatus, A. cruentus and A. hypochondriacus, with light seed colour and no dormancy, present these characteristics. They are distinguishable from the weeds A. spinosus, A. hybridus, A. blitum and A. viridis, with dark and dormant seeds. Their grains, with excellent protein quality, can be used in gluten-free special diets and livestock feed. The A. cruentus BRS Alegria, the first recommendation for grain production systems in Brazil, originated from mass selection in the variety AM 5189 of the United States. In double-cropping, after soybeans, it showed average yield of 2,359 kg ha-1 for grain and of 5,650 kg ha-1 for total biomass, in 90 days from emergence to maturity