Genomic and epigenomic responses to chronic stress involve miRNA-mediated programming

Stress represents a critical influence on motor system function and has been shown to impair movement performance. We hypothesized that stress-induced motor impairments are due to brain-specific changes in miRNA and protein-encoding gene expression. Here we show a causal link between stress-induced motor impairment and associated genetic and epigenetic responses in relevant central motor areas in a rat model. Exposure to two weeks of mild restraint stress altered the expression of 39 genes and nine miRNAs in the cerebellum. In line with persistent behavioural impairments, some changes in gene and miRNA expression were resistant to recovery from stress. Interestingly, stress up-regulated the expression of Adipoq and prolactin receptor mRNAs in the cerebellum. Stress also altered the expression of Prlr, miR-186, and miR-709 in hippocampus and prefrontal cortex. In addition, our findings demonstrate that miR-186 targets the gene Eps15. Furthermore, we found an age-dependent increase in EphrinB3 and GabaA4 receptors. These data show that even mild stress results in substantial genomic and epigenomic changes involving miRNA expression and associated gene targets in the motor system. These findings suggest a central role of miRNA-regulated gene expression in the stress response and in associated neurological function.     

Generating low immunogenic pig pancreatic islet cell clusters for xenotransplantation

Xenotransplantation of pancreatic islets offers a promising alternative to overcome the shortage of allogeneic donors. Despite significant advances, either immune rejection or oxygen supply in immune protected encapsulated islets remains major bottlenecks for clinical application. To decrease xenogeneic immune responses, we generated tissue engineered swine leucocyte antigen (SLA)‐silenced islet cell clusters (ICC). Single‐cell suspensions from pancreatic islets were generated by enzymatic digestion of porcine ICCs. Cells were silenced for SLA class I and class II by lentiviral vectors encoding for short hairpin RNAs targeting beta2‐microglobulin or class II transactivator, respectively. SLA‐silenced ICCs‐derived cells were then used to form new ICCs in stirred bioreactors in the presence of collagen VI. SLA class I silencing was designed to reach a level of up to 89% and class II by up to 81% on ICCs‐derived cells. Xenogeneic T cell immune responses, NK cell and antibody‐mediated cellular‐dependent immune responses were significantly decreased in SLA‐silenced cells. In stirred bioreactors, tissue engineered islets showed the typical 3D structure and insulin production. These data show the feasibility to generate low immunogenic porcine ICCs after single‐cell engineering and post‐transduction islet reassembling that might serve as an alternative to allogeneic pancreatic islet cell transplantation.     

Structural analysis of a putative aminoglycoside N-acetyltransferase from Bacillus anthracis

For the last decade, worldwide efforts for the treatment of anthrax infection have focused on developing effective vaccines. Patients that are already infected are still treated traditionally using different types of standard antimicrobial agents. The most popular are antibiotics such as tetracyclines and fluoroquinolones. While aminoglycosides appear to be less effective antimicrobial agents than other antibiotics, synthetic aminoglycosides have been shown to act as potent inhibitors of anthrax lethal factor and may have potential application as antitoxins. Here, we present a structural analysis of the BA2930 protein, a putative aminoglycoside acetyltransferase, which may be a component of the bacterium's aminoglycoside resistance mechanism. The determined structures revealed details of a fold characteristic only for one other protein structure in the Protein Data Bank, namely, YokD from Bacillus subtilis. Both BA2930 and YokD are members of the Antibiotic_NAT superfamily (PF02522). Sequential and structural analyses showed that residues conserved throughout the Antibiotic_NAT superfamily are responsible for the binding of the cofactor acetyl coenzyme A. The interaction of BA2930 with cofactors was characterized by both crystallographic and binding studies.     

PROLIFERATION KINETICS IN EPITHELIUM OF GUINEA-PIG COLON

The distribution of mitotic, DNA synthesizing and mature goblet cells along crypts of different length, situated in various regions of the colonic wall circumference, was determined. the distribution of proliferating cells can be approximated by a normal curve, and the distribution of mature goblet cells by an exponential curve. Some of the parameters of the distributions, different for various crypt classes, are shown to have common values when normalized by dividing them by the crypt length in a given class. the results are considered as indicating the manifestation of two levels of control of proliferation: one establishing the common pattern of the distributions along different crypts, and the second causing the differences in distributions depending on the region of the colonic wall.     

Airborne pollen in Kiev (Ukraine): gravimetric sampling

This article presents the results of aeropalynological observations in Kiev, carried out with a gravimetric method, during January–October, 1994. The six most abundant pollen types were: Betulaceae (21%), Chenopodiaceae/Amaranthaceae (10%), Ambrosia (10%), Artemisia (9%) Pinaceae (8%) and Poaceae (6%). Seasonal fluctuations of the atmospheric presence of tree/shrub and herb/grass pollen during the period March–September, 1993 and 1994, are also shown.     

House dust mite sensitization drives cross-reactive immune responses to homologous helminth proteins

The establishment of type 2 responses driven by allergic sensitization prior to exposure to helminth parasites has demonstrated how tissue-specific responses can protect against migrating larval stages, but, as a consequence, allow for immune-mediated, parasite/allergy-associated morbidity. In this way, whether helminth cross-reacting allergen-specific antibodies are produced and play a role during the helminth infection, or exacerbate the allergic outcome awaits elucidation. Thus, the main objective of the study was to investigate whether house dust mite (HDM) sensitization triggers allergen-specific antibodies that interact with Ascaris antigens and mediate antibody-dependent deleterious effects on these parasites as well as, to assess the capacity of cross-reactive helminth proteins to trigger allergic inflammation in house dust mite presensitized mice. Here, we show that the sensitization with HDM-extract drives marked IgE and IgG1 antibody responses that cross-react with Ascaris larval antigens. Proteomic analysis of Ascaris larval antigens recognized by these HDM-specific antibodies identified Ascaris tropomyosin and enolase as the 2 major HDM homologues based on high sequence and structural similarity. Moreover, the helminth tropomyosin could drive Type-2 associated pulmonary inflammation similar to HDM following HDM tropomyosin sensitization. The HDM-triggered IgE cross-reactive antibodies were found to be functional as they mediated immediate hypersensitivity responses in skin testing. Finally, we demonstrated that HDM sensitization in either B cells or FcγRIII alpha-chain deficient mice indicated that the allergen driven cell-mediated larval killing is not antibody-dependent. Taken together, our data suggest that aeroallergen sensitization drives helminth reactive antibodies through molecular and structural similarity between HDM and Ascaris antigens suggesting that cross-reactive immune responses help drive allergic inflammation.     

Efficiency of different PCR-based marker systems for assessment of Iris pumila genetic diversity

We investigated informativeness and effectiveness of different marker types (ISSR, IRAP, REMAP, RGAP and LP-PCR that employ primers based on the conservative sequences of abiotic stress response genes) to study genetic diversity of Iris pumila L. By the number of amplicons per primer, number of polymorphic amplicons per primer and resolving power index (Rp), ISSR-markers were the most efficient followed by LP-PCR-markers. In order of decreasing value of indicators of genetic diversity “the percentage of polymorphic bands”, and “the average Jaccard? genetic distance between plants”, marker systems may be arranged as follows: ISSR > RAPD > LP-PC > RGAP ≈ IRAP. For ISSR-markers, the percentage of polymorphic bands was 1.3–1.7 times higher than for the others, and the average genetic distance was 1.2–1.3 times higher. Different marker systems were ranked by the value of Nei? gene diversity and the Shannon? index as follows: ISSR > RAPD ≈ LP-PCR > RGAP ≈ IRAP, with the highest and the lowest values differing 1.4 times. Genetic population structure was investigated with program Structure 2.3. The data of all marker systems suggest that all genomes under study belonged to one population. The PCoA and cluster analyses based on genetic distances showed distinctions in clustering generated from different markers data and summarized data, as well as the lack of strong clusters. Mantel test revealed significant positive correlation between the matrices of genetic distances generated by the data of almost all marker systems. The strongest correlation was found between RGAP- and IRAP-markers (r = 0.452, p = 0.01) and between RGAP and ISSR (r = 0.430, p = 0.01). ISSR, RAPD and LP-PCR proved to be more effective for the study of I. pumila genetic diversity, nevertheless, joint use of different marker systems will provide a more comprehensive assessment of variation in different genomic regions.     

An AI-guided screen identifies probucol as an enhancer of mitophagy through modulation of lipid droplets

Failures in mitophagy, a process by which damaged mitochondria are cleared, results in neurodegeneration, while enhancing mitophagy promotes the survival of dopaminergic neurons. Using an artificial intelligence platform, we employed a natural language processing approach to evaluate the semantic similarity of candidate molecules to a set of well-established mitophagy enhancers. Top candidates were screened in a cell-based mitochondrial clearance assay. Probucol, a lipid-lowering drug, was validated across several orthogonal mitophagy assays. In vivo, probucol improved survival, locomotor function, and dopaminergic neuron loss in zebrafish and fly models of mitochondrial damage. Probucol functioned independently of PINK1/Parkin, but its effects on mitophagy and in vivo depended on ABCA1, which negatively regulated mitophagy following mitochondrial damage. Autophagosome and lysosomal markers were elevated by probucol treatment in addition to increased contact between lipid droplets (LDs) and mitochondria. Conversely, LD expansion, which occurs following mitochondrial damage, was suppressed by probucol and probucol-mediated mitophagy enhancement required LDs. Probucol-mediated LD dynamics changes may prime the cell for a more efficient mitophagic response to mitochondrial damage.

Failures in mitophagy, a process by which damaged mitochondria are cleared, results in neurodegeneration, while enhancing mitophagy promotes the survival of dopaminergic neurons. This study shows that the effects of Probucol on lipid droplet expansion can augment mitophagy in neurons, leading to locomotor improvements in zebrafish and fly models of Parkinson’s disease.