Project description:The Mesio-Temporal Lobe Epilepsy syndrome is the most common form of intractable epilepsy. It is characterized by recurrence of focal seizures and is often associated with hippocampal sclerosis and drug resistance. We aimed to characterize the molecular changes occurring during the initial stages of epileptogenesis in search of new therapeutic targets for Mesio-Temporal Lobe Epilepsy. We used a mouse model obtained by intra-hippocampal microinjection of kainate and performed hippocampal whole genome expression analysis at 6h, 12h and 24h post-injection, followed by multilevel bioinformatics analysis. We report significant changes in immune and inflammatory responses, neuronal network reorganization processes and glial functions, predominantly initiated during status epilepticus at 12h and persistent after the end of status epilepticus at 24h post-kainate. Upstream regulator analysis highlighted Cyba, Cybb and Vim as central regulators of multiple overexpressed genes implicated in glial responses at 24h. In silico microRNA analysis indicated that miR-9, miR-19b, miR-129, and miR-223 may regulate the expression of glial-associated genes at 24h. Our data support the hypothesis that glial-mediated inflammatory response holds a key role during epileptogenesis, and that microglial cells may participate in the initial process of epileptogenesis through increased ROS production via the NOX complex.
Project description:Infiltration of immune cells in primary tumors and metastatic sites is known to influence tumor progression and metastasis. Macrophages represent the most abundant immune cells in the tumor microenvironment, and evidence has shown that macrophages promote seeding, extravasation, and persistent growth of tumor cells at metastatic sites. miR-155 plays an essential role in immune cell development/function, and its aberrant expression is associated with lymphomas and several solid tumor types. However, it is unknown how miR-155 expression in immune cells affects solid tumor growth and metastasis. To this end, bone marrow transplantation was performed using miR-155-deficient mice as bone marrow donors and wild-type (WT) mice as recipients, and the chimeric mice were inoculated with tumor cells. We demonstrate that bone marrow lacking miR-155 significantly enhanced lung metastasis without a substantial effect on primary tumor growth. Relative to mice with WT bone marrow, miR-155-deficient bone marrow accumulated more macrophages in the spleen and lungs. Further analysis revealed that miR-155-deficient macrophages in metastatic sites exhibited a tumor-promoting M2 phenotype. In vitro study suggested that miR-155-null macrophages were prone to M2 polarization upon incubation with tumor cell-conditioned medium, due to elevated expression of C/EBP?, an identified miR-155 target. These data, for the first time, demonstrate that miR-155 in host immune cells plays a vital role in modulating solid tumor metastasis by affecting the recruitment and polarization of bone marrow-derived macrophages.Targeted inhibition of miR-155 delays tumor development but inhibition in host immune cells may encourage metastasis.
Project description:Bone marrow derived dendritic cells from Mus Musculus were cocultured with Candida albicans at a target ratio of 1:1 between 0 and 120 min and samples were collected every 30 minutes.
Project description:Islet samples were sequenced to determine the effect of miR-200 KO or miR-200 site mutation in Zeb1 on tumorigenesis in RT2 mice; re-expression of individual miR-200 family members in miR-200KO cells was performed to determine the individual roles of miR-141 and miR-200c seeds
Project description:Mammalian microRNAs are emerging as key regulators of the development and function of the immune system. Here, we report a strong but transient induction of miR-155 in mouse bone marrow after injection of bacterial lipopolysaccharide (LPS) correlated with granulocyte/monocyte (GM) expansion. Demonstrating the sufficiency of miR-155 to drive GM expansion, enforced expression in mouse bone marrow cells caused GM proliferation in a manner reminiscent of LPS treatment. However, the miR-155-induced GM populations displayed pathological features characteristic of myeloid neoplasia. Of possible relevance to human disease, miR-155 was found to be overexpressed in the bone marrow of patients with certain subtypes of acute myeloid leukemia (AML). Furthermore, miR-155 repressed a subset of genes implicated in hematopoietic development and disease. These data implicate miR-155 as a contributor to physiological GM expansion during inflammation and to certain pathological features associated with AML, emphasizing the importance of proper miR-155 regulation in developing myeloid cells during times of inflammatory stress.