Regulation of autophagy as a therapy for immunosenescence-driven cancer and neurodegenerative diseases: The role of exercise

Aging is one of the risk factors for the development of low-grade inflammation morbidities, such as several types of cancer and neurodegenerative diseases, due to changes in the metabolism, hormonal secretion, and immunosenescence. The senescence of the immune system leads to improper control of infections and tissue damage increasing age-related diseases. One of the mechanisms that maintain cellular homeostasis is autophagy, a cell-survival mechanism, and it has been proposed as one of the most powerful antiaging therapies. Regular exercise can reestablish autophagy, probably through AMP-activated protein kinase activation, and help in reducing the age-related senescence diseases. Therefore, in this study, we discuss the effects of exercise training in immunosenescence and autophagy, preventing the two main age-related disease, cancer and neurodegeneration.     

Effect of detection heterogeneity in occupancy‐detection models: an experimental test of time‐to‐first‐detection methods

Imperfect detection can bias estimates of site occupancy in ecological surveys but can be corrected by estimating detection probability. Time‐to‐first‐detection (TTD) occupancy models have been proposed as a cost–effective survey method that allows detection probability to be estimated from single site visits. Nevertheless, few studies have validated the performance of occupancy‐detection models by creating a situation where occupancy is known, and model outputs can be compared with the truth. We tested the performance of TTD occupancy models in the face of detection heterogeneity using an experiment based on standard survey methods to monitor koala Phascolarctos cinereus populations in Australia. Known numbers of koala faecal pellets were placed under trees, and observers, uninformed as to which trees had pellets under them, carried out a TTD survey. We fitted five TTD occupancy models to the survey data, each making different assumptions about detectability, to evaluate how well each estimated the true occupancy status. Relative to the truth, all five models produced strongly biased estimates, overestimating detection probability and underestimating the number of occupied trees. Despite this, goodness‐of‐fit tests indicated that some models fitted the data well, with no evidence of model misfit. Hence, TTD occupancy models that appear to perform well with respect to the available data may be performing poorly. The reason for poor model performance was unaccounted for heterogeneity in detection probability, which is known to bias occupancy‐detection models. This poses a problem because unaccounted for heterogeneity could not be detected using goodness‐of‐fit tests and was only revealed because we knew the experimentally determined outcome. A challenge for occupancy‐detection models is to find ways to identify and mitigate the impacts of unobserved heterogeneity, which could unknowingly bias many models.     

Targeted deletion of fatty acid transport protein-4 results in early embryonic lethality

Fatty acid transport protein-4 (FATP4) is the major FATP in the small intestine. We previously demonstrated, using in vitro antisense experiments, that FATP4 is required for fatty acid uptake into intestinal epithelial cells. To further examine the physiological role of FATP4, mice carrying a targeted deletion of FATP4 were generated. Deletion of one allele of FATP4 resulted in 48% reduction of FATP4 protein levels and a 40% reduction of fatty acid uptake by isolated enterocytes. However, loss of one FATP4 allele did not cause any detectable effects on fat absorption on either a normal or a high fat diet. Deletion of both FATP4 alleles resulted in embryonic lethality as crosses between heterozygous FATP4 parents resulted in no homozygous offspring; furthermore, no homozygous embryos were detected as early as day 9.5 of gestation. Early embryonic lethality has been observed with deletion of other genes involved in lipid absorption in the small intestine, namely microsomal triglyceride transfer protein and apolipoprotein B, and has been attributed to a requirement for fat absorption early in embryonic development across the visceral endoderm. In mice, the extraembryonic endoderm supplies nutrients to the embryo prior to development of a chorioallantoic placenta. In wild-type mice we found that FATP4 protein is highly expressed by the epithelial cells of the visceral endoderm and localized to the brush-border membrane of extraembryonic endodermal cells. This localization is consistent with a role for FATP4 in fat absorption in early embryogenesis and suggests a novel requirement for FATP4 function during development.     

Characterization of a heart-specific fatty acid transport protein

Fatty acids are a major source of energy for cardiac myocytes. Changes in fatty acid metabolism have been implicated as causal in diabetes and cardiac disease. The mechanism by which long chain fatty acids (LCFAs) enter cardiac myocytes is not well understood but appears to occur predominantly by protein-mediated transport. Here we report the cloning, expression pattern, and subcellular localization of a novel member of the fatty acid transport protein (FATP) family termed FATP6. FATP6 is principally expressed in the heart where it is the predominant FATP family member. Similar to other FATPs, transient and stable transfection of FATP6 into 293 cells enhanced uptake of LCFAs. FATP6 mRNA was localized to cardiac myocytes by in situ hybridization. Immunofluorescence microscopy of FATP6 in monkey and murine hearts revealed that the protein is exclusively located on the sarcolemma. FATP6 was restricted in its distribution to areas of the plasma membrane juxtaposed with small blood vessels. In these membrane domains FATP6 also colocalizes with another molecule involved in LCFA uptake, CD36. These findings suggest that FATP6 is involved in heart LCFA uptake, in which it may play a role in the pathogenesis of lipid-related cardiac disorders.     

Evidence for the involvement of the RNA-dependent protein kinase (PKR) in the induction of human cytotoxic T lymphocytes against a synthetic peptide of HIV-1 by regulatory RNA

The studies on the inhibitory effect exerted by Cholera Toxin (CT) on cell growth and proliferation indicate a remarkable heterogeneity of cell response suggesting that the inhibition represents the final event of many different ways or mechanisms . After CT binding, cAMP accumulation may not occur (as in L1210 leukemia cells) or, when occurring (as in SR-4987 stromal cells), may not be coupled with the antiproliferative effect of CT. In WEHI-3B cells CT binds a Gal-GalNac-GM1b receptor and the anticlonogenic effect of CT seems correlated with cAMP accumulation.To demonstrate the central role of cAMP in WEHI-3B cells, starting from the sensitive cell strain we selected and established a clone of WEHI-3B resistant to CT. This revertant clone (WEHI-3B/CT/REV) is currently cultured in the absence of CT and in the proliferation assay shows a dramatic resistance (>46,000 than the parental cells). Stimulation of WEHI-3B/CT/REV cells by cholera toxin failed to enhance cAMP and the ganglioside-CT binding studied on Thin Layer Chromatography (TLC) blots showed that the resistant cells lost the spot correspondent to the migration of Gal-GalNac-GM1b ganglioside. Both the lines respond at the same level to the adenylate cyclase stimulation by forskolin and the incorporation of GM1a did not decrease the resistance of WEHI-3B/CT/REV. These data confirm that Gal-GalNac-GM1b is the most important functional receptor for CT in WEHI-3B cells able to transduce the signal by enhancing cAMP which in turn inhibits cell proliferation (probably by cAMP dependent protein kinase activation). Our study describes the first cell line resistant to CT originated from a susceptible parental strain and provides a new interesting cell model for studying the cAMP dependent mechanisms involved in cell growth regulation.     

Monoamine oxidase inhibitory properties of optical isomers and N-substituted derivatives of 4-methylthioamphetamine

(+/-)-4-Methylthioamphetamine (MTA) was resolved into its enantiomers, and a series of N-alkyl derivatives of the parent compound, as well as its alpha-ethyl analogue, were prepared. The monoamine oxidase (MAO) inhibitory properties of these substances were evaluated in vitro, using a crude rat brain mitochondrial suspension as the source of enzyme. All compounds produced a selective, reversible and concentration-related inhibition of MAO-A. (+)-MTA proved to be the most potent inhibitor studied, while all the other derivatives were less active than the parent compound, with (-)-MTA being about 18 times less potent than the (+) isomer. The analysis of structure-activity relationships indicates that the introduction of alkyl substituents on the amino group of MTA leads to a reduction in the potency of the derivatives as MAO-A inhibitors, an effect which increases with the size of the substituent.     

Micropropagation ofMinthostachys mollis (H.B.K.) grieseb. and essential oil composition of clonally propagated plants

Summary Cultures ofMinthostachys mollis were established from nodal explants obtained under aseptic conditions. Explants were cultured on Murashige and Skoog (MS) half-strength medium containing 6-benzyladenine (BA), and/or naphthaleneacetic acid (NAA). Optimum numbers of healthy shoots were induced on media containing 0.05 μM NAA plus 2.2 μM BA; higher concentrations caused more hyperhydricity and less extension. Rooting was achieved on half-strength MS medium with 0.05 μM NAA. Plantlets were acclimatized and successfully transferred to soil. Essential oil composition of the regenerated plants were determined by gas chromatography/mass spectrometry and little differences were found in the essential oil composition with the plant grown in the wild.