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- Korpetinou, Angeliki, et al.
(author)
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Serglycin Is Implicated in the Promotion of Aggressive Phenotype of Breast Cancer Cells
- 2013
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Journal article (peer-reviewed)abstract
- Serglycin is a proteoglycan expressed by some malignant cells. It promotes metastasis and protects some tumor cells from complement system attack. In the present study, we show for the first time the in situ expression of serglycin by breast cancer cells by immunohistochemistry in patients' material. Moreover, we demonstrate high expression and constitutive secretion of serglycin in the aggressive MDA-MB-231 breast cancer cell line. Serglycin exhibited a strong cytoplasmic staining in these cells, observable at the cell periphery in a thread of filaments near the cell membrane, but also in filopodia-like structures. Serglycin was purified from conditioned medium of MDA-MB-231 cells, and represented the major proteoglycan secreted by these cells, having a molecular size of similar to 250 kDa and carrying chondroitin sulfate side chains, mainly composed of 4-sulfated (similar to 87%), 6-sulfated (similar to 10%) and non-sulfated (similar to 3%) disaccharides. Purified serglycin inhibited early steps of both the classical and the lectin pathways of complement by binding to C1q and mannose-binding lectin. Stable expression of serglycin in less aggressive MCF-7 breast cancer cells induced their proliferation, anchorage-independent growth, migration and invasion. Interestingly, over-expression of serglycin lacking the glycosaminoglycan attachment sites failed to promote these cellular functions, suggesting that glycanation of serglycin is a pre-requisite for its oncogenic properties. Our findings suggest that serglycin promotes a more aggressive cancer cell phenotype and may protect breast cancer cells from complement attack supporting their survival and expansion.
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- Prydz, A, et al.
(author)
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Pro-Inflammatory Role of AQP4 in Mice Subjected to Intrastriatal Injections of the Parkinsonogenic Toxin MPP
- 2020
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In: Cells. - : MDPI AG. - 2073-4409. ; 9:11
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Journal article (peer-reviewed)abstract
- Aquaporin-4 (AQP4) is critically involved in brain water and volume homeostasis and has been implicated in a wide range of pathological conditions. Notably, evidence has been accrued to suggest that AQP4 plays a proinflammatory role by promoting release of astrocytic cytokines that activate microglia and other astrocytes. Neuroinflammation is a hallmark of Parkinson’s disease (PD), and we have previously shown that astrocytes in substantia nigra (SN) are enriched in AQP4 relative to cortical astrocytes, and that their complement of AQP4 is further increased following treatment with the parkinsonogenic toxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). Here, we investigated the effect of Aqp4 deletion on microglial activation in mice subjected to unilateral intrastriatal injection of 1-methyl-4-phenylpyridinium (MPP+, the toxic metabolite of MPTP). Our results show that MPP+ injections lead to a pronounced increase in the expression level of microglial activating genes in the ventral mesencephalon of wild type (WT) mice, but not Aqp4−/− mice. We also show, in WT mice, that MPP+ injections cause an upregulation of nigral AQP4 and swelling of astrocytic endfeet. These findings are consistent with the idea that AQP4 plays a pro-inflammatory role in Parkinson’s disease, secondary to the dysregulation of astrocytic volume homeostasis.
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- Zahl, S, et al.
(author)
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Aquaporin-9 in the Brain Inflammatory Response: Evidence from Mice Injected with the Parkinsonogenic Toxin MPP
- 2023
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In: Biomolecules. - : MDPI AG. - 2218-273X. ; 13:4
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Journal article (peer-reviewed)abstract
- More than 20 years have passed since the first demonstration of Aquaporin-9 (AQP9) in the brain. Yet its precise localization and function in brain tissue remain unresolved. In peripheral tissues, AQP9 is expressed in leukocytes where it is involved in systemic inflammation processes. In this study, we hypothesized that AQP9 plays a proinflammatory role in the brain, analogous to its role in the periphery. We also explored whether Aqp9 is expressed in microglial cells, which would be supportive of this hypothesis. Our results show that targeted deletion of Aqp9 significantly suppressed the inflammatory response to the parkinsonian toxin 1-methyl-4-phenylpyridinium (MPP+). This toxin induces a strong inflammatory response in brain. After intrastriatal injections of MPP+, the increase in transcript levels of proinflammatory genes was less pronounced in AQP9−/− mice compared with wild-type controls. Further, in isolated cell subsets, validated by flow cytometry we demonstrated that Aqp9 transcripts are expressed in microglial cells, albeit at lower concentrations than in astrocytes. The present analysis provides novel insight into the role of AQP9 in the brain and opens new avenues for research in the field of neuroinflammation and chronic neurodegenerative disease.
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