Chronic postnatal ornithine administration to rats provokes learning deficit in the open field task

Mitochondrial Transplantation Attenuates Brain Dysfunction in Sepsis by Driving Microglial M2 Polarization

Activation of microglia and mitochondrial dysfunction are two major contributors to the pathogenesis of sepsis-associated brain dysfunction. Mitochondrial dysfunction can alter the immunological profile of microglia favoring to a pro-inflammatory phenotype. Mitochondrial transplantation, as an emerging mitochondria-targeted therapy, possesses considerable therapeutic potential in various central nervous system injuries or diseases. However, the effects of mitochondrial transplantation on microglial polarization and neuroprotection after sepsis remain unclear. In this study, lipopolysaccharide (LPS)/interferon-γ (IFN-γ) and interleukin-4 (IL-4)/interleukin-13 (IL-13) were used to induce different phenotypes of BV2 microglial cells. We observed that mitochondrial content and function were enhanced in IL-4-/IL-13-stimulated microglia. In vitro, mitochondria treatment conferred neuroprotection by enhancing microglial polarization from the M1 phenotype to the M2 phenotype and suppressing microglial-derived inflammatory cytokine release. Furthermore, microglial phenotypes and behavior tests were assessed after mice were subjected to sepsis by cecal ligation and puncture (CLP) followed by intracerebroventricular injection of exogenous functional mitochondria. We found that mitochondrial transplantation induced microglial M2 rather than M1 response 24 h after sepsis. Mitochondrial transplantation improved behavioral deficits by increasing the latency time in inhibitory avoidance test and decreasing the number of crossing and rearing in the test session of open field test 10 days after CLP onset. These findings indicate that mitochondrial transplantation promotes the phenotypic conversion of microglia and improves cognitive impairment in sepsis survivors, supporting the potential use of exogenous mitochondrial transplantation therapy that may be a potential therapeutic opportunity for sepsis-associated brain dysfunction.

The clinical measurement, measurement method and experimental condition ontologies: expansion, improvements and new applications

BACKGROUND

The Clinical Measurement Ontology (CMO), Measurement Method Ontology (MMO), and Experimental Condition Ontology (XCO) were originally developed at the Rat Genome Database (RGD) to standardize quantitative rat phenotype data in order to integrate results from multiple studies into the PhenoMiner database and data mining tool. These ontologies provide the framework for presenting what was measured, how it was measured, and under what conditions it was measured.

RESULTS

There has been a continuing expansion of subdomains in each ontology with a parallel 2-3 fold increase in the total number of terms, substantially increasing the size and improving the scope of the ontologies. The proportion of terms with textual definitions has increased from ~60% to over 80% with greater synchronization of format and content throughout the three ontologies. Representation of definition source Uniform Resource Identifiers (URI) has been standardized, including the removal of all non-URI characters, and systematic versioning of all ontology files has been implemented. The continued expansion and success of these ontologies has facilitated the integration of more than 60,000 records into the RGD PhenoMiner database. In addition, new applications of these ontologies, such as annotation of Quantitative Trait Loci (QTL), have been added at the sites actively using them, including RGD and the Animal QTL Database.

CONCLUSIONS

The improvements to these three ontologies have been substantial, and development is ongoing. New terms and expansions to the ontologies continue to be added as a result of active curation efforts at RGD and the Animal QTL database. Use of these vocabularies to standardize data representation for quantitative phenotypes and quantitative trait loci across databases for multiple species has demonstrated their utility for integrating diverse data types from multiple sources. These ontologies are freely available for download and use from the NCBO BioPortal website at http://bioportal.bioontology.org/ontologies/1583 (CMO), http://bioportal.bioontology.org/ontologies/1584 (MMO), and http://bioportal.bioontology.org/ontologies/1585 (XCO), or from the RGD ftp site at ftp://rgd.mcw.edu/pub/ontology/.

Changes of hippocampal beta-alanine and citrulline levels are paralleling early and late phase of retrieval in the Morris Water Maze

Although a series of amino acids (AA) have been associated with spatial memory formation, there is limited information on concentrations of beta-alanine and citrulline in rodent brains. Given the importance of AA metabolism in cognitive functions it was the aim of the study to determine hippocampal levels of beta-alanine and citrulline in rats during two different phases of memory retrieval in a spatial memory paradigm. Ten rats were used per group and the first group was trained and sacrificed five min, the second six hours following retrieval in the Morris Water Maze (MWM) and the third and fourth group were untrained, yoked controls. Hippocampi were taken and free AA were determined using a well-established HPLC protocol. Beta-alanine and citrulline levels were higher in trained rat hippocampi, during both, early and late phase of memory retrieval. Taurine, methionine, cysteine, lysine and ornithine levels were higher in yoked rats at the late phase while tyrosine was higher in yoked rats during the early phase. There were no significant correlations between time spent in the target quadrant and any of the AA levels. Herein, an AA pattern, different between yoked and trained animals at early and late phase of memory retrieval is shown, indicating probable involvement of different AA pathways in animals trained and untrained in the MWM. The results may be useful for the interpretation of previous studies and the design of future experiments to identify amino acids as possible targets for modulating spatial memory.