Protection from endotoxic uveitis by intravitreal Resolvin D1: involvement of lymphocytes, miRNAs, ubiquitin-proteasome, and M1/M2 macrophages.

This study investigated the protective effects of intravitreal Resolvin D1 (RvD1) against LPS-induced rat endotoxic uveitis (EIU). RvD1 was administered into the right eye at a single injection of 5 µL volume containing 10-100-1000 ng/kg RvD1 1 h post-LPS injection (200 µg, Salmonella minnesota) into thefootpad of Sprague-Dawley rats. 24 h later, the eye was enucleated and examined for clinical, biochemical, and immunohistochemical evaluations. RvD1 significantly and dose-dependently decreased the clinical score attributed to EIU, starting from the dose of 10 ng/kg and further decreased by 100 and 1000 ng/kg. These effects were accompanied by changes in four important determinants of the immune-inflammatory response within the eye: (i) the B and T lymphocytes, (ii) the miRNAs pattern, (iii) the ubiquitin-proteasome system (UPS), and (iv) the M1/M2 macrophage phenotype. LPS+RvD1 treated rats showed reduced presence of B and T lymphocytes and upregulation of miR-200c-3p, miR 203a-3p, miR 29b-3p, and miR 21-5p into the eye compared to the LPS alone. This was paralleled by decreases of the ubiquitin, 20S and 26S proteasome subunits, reduced presence of macrophage M1, and increased presence of macrophage M2 in the ocular tissues. Accordingly, the levels of the cytokine TNF-α, the chemokines MIP1-α and NF-κB were reduced.

DNA (cytosine-5) methyltransferase turnover and cellular localization in developing Paracentrotus lividus sea urchin embryo.

The turnover and localization of the enzyme DNA (cytosine-5) methyltransferase (Dnmt1) were studied during Paracentrotus lividus sea urchin embryo development using antibody preparations against the NH(2) and COOH-terminal regions of the molecule. The antibodies reveal, by Western blots and whole-mount analyses, that the enzyme is differently required during embryonic development. The changeover point is at blastula stage, where a proteolytic mechanism hydrolyses the enzyme present in all embryonic cells by removing a peptide of about 45 kDa from the amino terminal region of the 190 kDa enzyme initially synthesized on maternal transcripts. The resulting 145 kDa enzyme shows modified catalytic properties, different antibody reactivity and is rapidly destroyed in the few hours before gastrulation. At more advanced stages of development the enzyme is newly synthesized but only in particular cell types, among which neurons. The data show that Dnmt1 is removed from embryonic cells before gastrulation to be synthesized again at different levels in different cell types, indicating that the concentration of Dnmt1 is critical for the various differentiated cells of the developing sea urchin embryo.

Characterization of a new variant DNA (cytosine-5)-methyltransferase unable to methylate double stranded DNA isolated from the marine annelid worm Chaetopterus variopedatus.

The enzyme S-adenosylmethionine-DNA (cytosine-5)-methyltransferase has been identified, first time for invertebrates, in embryos of the marine polychaete annelid worm Chaetopterus variopedatus. The molecule has been isolated from embryos at 15 h of development. It is a single peptide of about 200 kDa molecular weight, cross-reacting with antibodies against sea urchin DNA methyltransferase. The enzymatic properties of the molecule are similar to those of Dnmt1 methyltransferases isolated from other organisms, but with the peculiarity to be unable to make 'de novo' methylation on double stranded DNA.

Organization and nucleotide sequence of the cluster of five histone genes in the polichaete worm Chaetopterus variopedatus: first record of a H1 histone gene in the phylum Annelida.

Histone genes were identified and their nucleotide sequences were determined in the polychaete marine worm Chaetopterus variopedatus. The genes are organized in about 390 clusters of 7.3 kbp. Each cluster contains one copy of the five histone genes. The H1 histone gene present in the clusters is the first ever isolated in the phylum Annelida. The cluster has the unique peculiarity that all genes contain both the replication-dependent and the replication-independent 3' mRNA termination signals. Despite the differences in cluster organization and transcription polarity of the individual histone genes between C. variopedatus and Platynereis dumerilii, the other annelid in which histone genes have been studied, phylogenetic analysis of the encoded amino acid sequences clearly groups together those two organisms in a tree in which the other studied worms find closely related positions on the same evolutionary branch.