SUMMARYPeripheral nerve development involves multiple classes of glia that cooperate to form overlapping glial layers paired with the deposition of a surrounding extracellular matrix (ECM). The formation of this tubular structure protects the ensheathed axons from physical and pathogenic damage and from changes in the ionic environment. Integrins, a major family of ECM receptors, play a number of roles in the development of myelinating Schwann cells, one class of glia ensheathing the peripheral nerves of vertebrates. However, the identity and the role of the integrin complexes utilized by the other classes of peripheral nerve glia have not been determined in any animal. Here, we show that, in the peripheral nerves of Drosophila melanogaster, two integrin complexes (PS2PS and PS3PS) are expressed in the different glial layers and form adhesion complexes with integrin-linked kinase and Talin. Knockdown of the common beta subunit (PS) using inducible RNAi in all glial cells results in lethality and glial defects. Analysis of integrin complex function in specific glial layers showed that loss of PS in the outermost layer (the perineurial glia) results in a failure to wrap the nerve, a phenotype similar to that of Matrix metalloproteinase 2-mediated degradation of the ECM. Knockdown of PS integrin in the innermost wrapping glia causes a loss of glial processes around axons. Together, our data suggest that integrins are employed in different glial layers to mediate the development and maintenance of the protective glial sheath in Drosophila peripheral nerves.
B7-H1/PD-1 pathway may be linked to malignant potential of ICC and contribute to tumor immune evasion by promoting CD8+ TILs apoptosis. Thus, this pathway may indeed be a potential therapeutic target in the treatment of this disease.
These results suggest that the balance of effector CD4+ Th responses (Th17 and Th1 responses) and regulatory response is an important element of immune regulation. Inappropriate, excessive, and non-specific Th17 and Th1 effector responses may be involved in the pathogenesis of HBV-associated liver inflammation and hepatocellular damage. Th17 response, especially, may exacerbate the inflammatory processes leading to liver failure. IL-17-mediating liver neutrophil recruitment via induction of IL-8 may be one potential mechanism of liver injury in patients with hepatitis B. An improved understanding of the factors that influence the differentiation and function of these cell types in vivo will be of great importance to the future development of immune therapies in HBV-associated liver disease.
Post-translational modification of histones plays essential roles in the transcriptional regulation of genes in eukaryotes. Methylation on basic residues of histones is regulated by histone methyltransferases and histone demethylases, and misregulation of these enzymes has been linked to a range of diseases such as cancer. Histone lysine demethylase 2 (KDM2) family proteins have been shown to either promote or suppress tumorigenesis in different human malignancies. However, the roles and regulation of KDM2 in development are poorly understood, and the exact roles of KDM2 in regulating demethylation remain controversial. Since KDM2 proteins are highly conserved in multicellular animals, we analyzed the KDM2 ortholog in Drosophila. We have observed that dKDM2 is a nuclear protein and its level fluctuates during fly development. We generated three deficiency lines that disrupt the dKdm2 locus, and together with 10 transposon insertion lines within the dKdm2 locus, we characterized the developmental defects of these alleles. The alleles of dKdm2 define three phenotypic classes, and the intragenic complementation observed among these alleles and our subsequent analyses suggest that dKDM2 is not required for viability. In addition, loss of dKDM2 appears to have rather weak effects on histone H3 lysine 36 and 4 methylation (H3K36me and H3K4me) in the third instar wandering larvae, and we observed no effect on methylation of H3K9me2, H3K27me2 and H3K27me3 in dKdm2 mutants. Taken together, these genetic, molecular and biochemical analyses suggest that dKDM2 is not required for viability of flies, indicating that dKdm2 is likely redundant with other histone lysine demethylases in regulating normal development in Drosophila.
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