Project description:We used single cell RNA sequencing (scRNA-seq) to analyze the heterogeneity of 482N1 brain metastatic cells intracranially injected
Project description:Cerebral metastases occur in a majority of metastatic melanoma patients and are a major cause of mortality. Despite this, there is a poor understanding of the molecules/pathways that lead to the brain-metastatic phenotype. Studies designed to address this deficiency and test novel therapeutic approaches have until recently been slowed by an absence of preclinical models of spontaneous CNS metastatic melanoma disease. To address this, we isolated two variants of the human melanoma cell line WM239 (named 131/4-5B1 and 131/4-5B2) which can metastasize spontaneously to brain parenchyma from an orthotopic primary transplant. We have performed gene expression profiling on both brain metastatic cell lines (131/4-5B1 and 131/4-5B2) and compared to the poorly metastatic parental cell line WM239A and a derived highly metastatic variant 113/6-4L in order to examine the mechanisms that influence the progression of malignant melanoma to a brain-metastatic phenotype. Two-condition experiment, brain metastatic cell lines (131/4-5B1 and 131/4-5B2) and compared to the poorly metastatic parental cell line WM239A and a derived highly metastatic variant 113/6-4L. Biological replicates: 4 independently grown and harvested cell line passages. Two technical replicate per condition (including dye swap).
Project description:Cerebral metastases occur in a majority of metastatic melanoma patients and are a major cause of mortality. Despite this, there is a poor understanding of the molecules/pathways that lead to the brain-metastatic phenotype. Studies designed to address this deficiency and test novel therapeutic approaches have until recently been slowed by an absence of preclinical models of spontaneous CNS metastatic melanoma disease. To address this, we isolated two variants of the human melanoma cell line WM239 (named 131/4-5B1 and 131/4-5B2) which can metastasize spontaneously to brain parenchyma from an orthotopic primary transplant. We have performed gene expression profiling on both brain metastatic cell lines (131/4-5B1 and 131/4-5B2) and compared to the poorly metastatic parental cell line WM239A and a derived highly metastatic variant 113/6-4L in order to examine the mechanisms that influence the progression of malignant melanoma to a brain-metastatic phenotype.
Project description:Brain metastasis is a significant cause of morbidity and mortality in multiple cancer types and represents an unmet clinical need. The mechanisms that mediate metastatic cancer growth in the brain parenchyma are largely unknown. Melanoma, which has the highest rate of brain metastasis among common cancer types, is an ideal model to study how cancer cells adapt to the brain parenchyma. We utilized pairs of brain metastasis-derived (BM) and non-brain metastasis-derived (NBM) melanoma short term cultures (STCs) obtained from the same patient. We performed TMT based multiplexed analysis of these cell lines using off-line fractionation to increase our proteomics coverage. Our unbiased proteomics analysis of these melanoma short-term cultures revealed that proteins implicated in neurodegenerative pathologies are differentially expressed in melanoma cells explanted from brain metastases compared to those derived from extracranial metastases. We showed that melanoma cells require amyloid beta for growth and survival in the brain parenchyma. Melanoma-secreted A beta activates surrounding astrocytes to a pro-metastatic, anti-inflammatory phenotype and prevents phagocytosis of melanoma by microglia. Finally, we demonstrate that pharmacological inhibition of Abeta decreases brain metastatic burden.
Project description:Inflammation triggers secondary brain damage after stroke. The meninges and other CNS border compartments serve as invasion sites for leukocyte influx into the brain thus promoting tissue damage after stroke. However, the post-ischemic immune response of border compartments compared to brain parenchyma remains poorly characterized . Here, we deeply characterize tissue-resident leukocytes in meninges and brain parenchyma by flow cytometry, histology, and single cell transcriptomics after experimental stroke and discover that leukocytes respond differently to stroke depending on their site of residence. We thereby discover a unique phenotype of myeloid cells exclusive to the brain after stroke. These stroke-associated myeloid cells partially resemble neurodegenerative disease-associated microglia. They are mainly of resident microglial origin, partially conserved in humans and exhibit a lipid-phagocytosing phenotype. Blocking markers specific for these cells partially ameliorates stroke outcome thus providing a potential therapeutic target. The injury-response of myeloid cells in the CNS is thus compartmentalized, adjusted to the type of injury and may represent a therapeutic target.
Project description:Ms4a3-Cre: R26-TdTomato: Cx3cr1-gfp mice allow discrimination between YS-derivd and monocyte-derived macrophages in the brain parenchyma and leptomeninges by color. We used single cell RNAseq for RNA profiling to compare YS-derived micrglia, monocyte-derived microglia, YS-derived leptomeningeal macrophages, and monocyte-derived leptomeningeal macrophages.
Project description:While modern high efficacy disease modifying therapies have revolutionized the treatment of relapsing-remitting multiple sclerosis, they are less effective at controlling the progressive forms of the disease. Meningeal inflammation is a recognized risk factor for cortical grey matter pathology which can result in disabling symptoms such as cognitive impairment and depression, but the mechanisms linking meningeal inflammation and grey matter pathology remain unclear. Here, we performed MRI-guided spatial transcriptomics in a mouse model of autoimmune meningeal inflammation to characterize the transcriptional signature in areas of meningeal inflammation and the underlying brain parenchyma. We found broadly increased activity of inflammatory signaling pathways at sites of meningeal inflammation, but only a subset of these pathways active in the adjacent brain parenchyma. Sub-clustering of regions adjacent to meningeal inflammation revealed the subset of immune programs induced in brain parenchyma, notably the B cell mediated immune response and antigen processing/presentation. Trajectory analysis of spatially resolved spots confirmed variable penetration of immune signatures originating from meningeal inflammation into the adjacent brain tissue. This work contributes a valuable data resource to the field, provides the first detailed spatial transcriptomic characterization in a model of meningeal inflammation, and highlights several candidate pathways in the pathogenesis of grey matter pathology.
Project description:Brain metastasis is a significant cause of morbidity and mortality in multiple cancer types and represents an unmet clinical need. The mechanisms that mediate metastatic cancer growth in the brain parenchyma are largely unknown. Melanoma, which has the highest rate of brain metastasis among common cancer types, is an ideal model to study how cancer cells adapt to the brain parenchyma. Our unbiased proteomics analysis of melanoma short-term cultures revealed that proteins implicated in neurodegenerative pathologies are differentially expressed in melanoma cells explanted from brain metastases compared to those derived from extracranial metastases. We showed that melanoma cells require amyloid beta (Ab) for growth and survival in the brain parenchyma. Melanoma-secreted Ab activates surrounding astrocytes to a prometastatic, anti-inflammatory phenotype and prevents phagocytosis of melanoma by microglia. Finally, we demonstrate that pharmacological inhibition of Ab decreases brain metastatic burden.