Neonatal Exposure to Bacterial Lipopolysaccharide Affects Behavior and Expression of Ionotropic Glutamate Receptors in the Hippocampus of Adult Rats after Psychogenic Trauma

Biochemistry (Moscow) - According to the two-hit hypothesis of psychoneuropathology formation, infectious diseases and other pathological conditions occurring during the critical periods of early...     

Quercetin and hydroxytyrosol as modulators of hepatic steatosis: A NAFLD‐on‐a‐chip study

Organs‐on‐chip (OoCs) are catching on as a promising and valuable alternative to animal models, in line with the 3Rs initiative. OoCs enable the creation of three‐dimensional (3D) tissue microenvironments with physiological and pathological relevance at unparalleled precision and complexity, offering new opportunities to model human diseases and to test the potential therapeutic effect of drugs, while overcoming the limited predictive accuracy of conventional 2D culture systems. Here, we present a liver‐on‐a‐chip model to investigate the effects of two naturally occurring polyphenols, namely quercetin and hydroxytyrosol, on nonalcoholic fatty liver disease (NAFLD) using a high‐content analysis readout methodology. NAFLD is currently the most common form of chronic liver disease; however, its complex pathogenesis is still far from being elucidated, and no definitive treatment has been established so far. In our experiments, we observed that both polyphenols seem to restrain the progression of the free fatty acid‐induced hepatocellular steatosis, showing a cytoprotective effect due to their antioxidant and lipid‐lowering properties. In conclusion, the findings of the present work could guide novel strategies to contrast the onset and progression of NAFLD.     

Split-wrmScarlet and split-sfGFP: tools for faster,easier fluorescent labeling of endogenous proteins in Caenorhabditis elegans

We create and share a new red fluorophore, along with a set of strains, reagents and protocols, to make it faster and easier to label endogenous Caenorhabditis elegans proteins with fluorescent tags. CRISPR-mediated fluorescent labeling of C. elegans proteins is an invaluable tool, but it is much more difficult to insert fluorophore-size DNA segments than it is to make small gene edits. In principle, high-affinity asymmetrically split fluorescent proteins solve this problem in C. elegans: the small fragment can quickly and easily be fused to almost any protein of interest, and can be detected wherever the large fragment is expressed and complemented. However, there is currently only one available strain stably expressing the large fragment of a split fluorescent protein, restricting this solution to a single tissue (the germline) in the highly autofluorescent green channel. No available C. elegans lines express unbound large fragments of split red fluorescent proteins, and even state-of-the-art split red fluorescent proteins are dim compared to the canonical split-sfGFP protein. In this study, we engineer a bright, high-affinity new split red fluorophore, split-wrmScarlet. We generate transgenic C. elegans lines to allow easy single-color labeling in muscle or germline cells and dual-color labeling in somatic cells. We also describe a novel expression strategy for the germline, where traditional expression strategies struggle. We validate these strains by targeting split-wrmScarlet to several genes whose products label distinct organelles, and we provide a protocol for easy, cloning-free CRISPR/Cas9 editing. As the collection of split-FP strains for labeling in different tissues or organelles expands, we will post updates at doi.org/10.5281/zenodo.3993663     

The pathogenic potential of the combined action of chronic Opisthorchis felineus infection and repeated social defeat stress in C57BL/6 mice

Parasitic food-borne diseases and chronic social stress are frequent attributes of day-to-day human life. Therefore, our aim was to model the combined action of chronic Opisthorchis felineus infection and repeated social defeat stress in C57BL/6 mice. Histological examination of the liver revealed inflammation sites, pronounced periductal fibrosis, and cholangiofibrosis together with proliferation of bile ducts and hepatocyte dystrophy in the infected mice, especially in the stress-exposed ones. Simultaneously with liver pathology, we detected significant structural changes in the cerebral cortex. Immunohistochemical analysis of the hippocampus indicated the highest increase in numerical density of Iba 1-, IL-6-, iNOS-, and Arg1-positive cells in mice simultaneously subjected to the two adverse factors. The number of GFAP-positive cells rose during repeated social defeat stress, most strongly in the mice subjected to both infection and stress. Real-time PCR analysis showed that the expression of genes Aif1 and Il6 differed among the analysed brain regions (hippocampus, hypothalamus, and frontal cortex) and depended on the adverse factors applied. In addition, among the brain regions, there was no consistent increase or decrease in these parameters when the two adverse treatments were combined: (i) in the hippocampus, there was upregulation of Aif1 and no change in Il6 expression; (ii) in the hypothalamus, expression levels of Aif1 and Il6 were not different from controls; and (iii) in the frontal cortex, Aif1 expression did not change while Il6 expression increased. It can be concluded that a combination of two long-lasting adverse factors, O. felineus infection and repeated social defeat stress, worsens not only the hepatic but also brain state, as evidenced behaviorally by disturbances of the startle response in mice.     

Abiotic factors driving cyanobacterial biomass and composition under perennial bloom conditions in tropical latitudes

Hydrobiologia - While warming and eutrophication have increased the frequency and magnitude of harmful cyanobacterial blooms globally, the scenario for many eutrophic tropical freshwaters is a...