Intra‐ versus extracellular effects of microglia‐derived cysteine proteases in a conditioned medium transfer model

Wendt, Wiebke; Schulten, R.; Stichel, Christine C.; Lübbert, Hermann

doi:10.1111/j.1471-4159.2009.06283.x

Cited by 29 publications

(43 citation statements)

References 53 publications

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“…Using the murine N-13 microglial cell line, one study reported that LPS decreased Cat S cellular levels and activity but increased its secretion [58], and another showed that basic fibroblast growth factor increased both intra- and extracellular Cat S activity [54]. In the BV-2 microglia cell line, LPS increased intracellular levels of Cat S and Cat X but evoked secretion of Cat -B, -K, -S and -X [61]. Interestingly, co-stimulation of the P2X7 purinergic receptor was necessary for secretion of enzymatically active Cat S from LPS-treated rat primary microglia [62].…”

Section: Discussionmentioning

confidence: 99%

The microglial activation state regulates migration and roles of matrix-dissolving enzymes for invasion

Lively

Schlichter

2013

J Neuroinflammation

163

177

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BackgroundMicroglial cells are highly mobile under many circumstances and, after central nervous system (CNS) damage, they must contend with the dense extracellular matrix (ECM) in order to reach their target sites. In response to damage or disease, microglia undergo complex activation processes that can be modulated by environmental cues and culminate in either detrimental or beneficial outcomes. Thus, there is considerable interest in comparing their pro-inflammatory (‘classical’ activation) and resolving ‘alternative’ activation states. Almost nothing is known about how these activation states affect the ability of microglia to migrate and degrade ECM, or the enzymes used for substrate degradation. This is the subject of the present study.MethodsPrimary cultured rat microglial cells were exposed to lipopolysaccharide (LPS) to evoke classical activation or IL4 to evoke alternative activation. High-resolution microscopy was used to monitor changes in cell morphology and aspects of the cytoskeleton. We quantified migration in a scratch-wound assay and through open filter holes, and invasion through Matrigel™. A panel of inhibitors was used to analyze contributions of different matrix-degrading enzymes to migration and invasion, and quantitative real-time reverse transcriptase PCR (qRT-PCR) was used to assess changes in their expression.ResultsVinculin- and F-actin-rich lamellae were prominent in untreated and IL4-treated microglia (but not after LPS). IL4 increased the migratory capacity of microglia but eliminated the preferential anterior nuclear-centrosomal axis polarity and location of the microtubule organizing center (MTOC). Microglia degraded fibronectin, regardless of treatment, but LPS-treated cells were relatively immobile and IL4-treated cells invaded much more effectively through Matrigel™. For invasion, untreated microglia primarily used cysteine proteases, but IL4-treated cells used a wider range of enzymes (cysteine proteases, cathepsin S and K, heparanase, and matrix metalloproteases). Untreated microglia expressed MMP2, MMP12, heparanase, and four cathepsins (B, K, L1, and S). Each activation stimulus upregulated a different subset of enzymes. IL4 increased MMP2 and cathepsins S and K; whereas LPS increased MMP9, MMP12, MMP14 (MT1-MMP), heparanase, and cathepsin L1.ConclusionsMicroglial cells migrate during CNS development and after CNS damage or disease. Thus, there are broad implications of the finding that classically and alternatively activated microglia differ in morphology, cytoskeleton, migratory and invasive capacity, and in the usage of ECM-degrading enzymes.

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Section: Discussionmentioning

confidence: 99%

The microglial activation state regulates migration and roles of matrix-dissolving enzymes for invasion

Lively

Schlichter

2013

J Neuroinflammation

163

177

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“…However, in several neuropathologies, where chronic inflammation is present, the inflammatory products derived from activated microglia may also promote neurodegeneration and contribute to neuronal loss (Gonz alez-Scarano & Baltuch, 1999). In addition to inflammatory cytokines, activated microglia secretes lysosomal proteases, the cathepsins, including cathepsin X (Nakanishi, 2003;Wendt et al, 2009). Cathepsin X expression and proteolytic activity were strongly upregulated in the mouse brain, in particular in glial cells and aged neurons, and its association with senile plaques was also observed (Wendt et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Neuroprotective role of γ‐enolase in microglia in a mouse model of Alzheimer's disease is regulated by cathepsin X

et al. 2013

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Summaryc-Enolase is a neurotrophic-like factor promoting growth, differentiation, survival and regeneration of neurons. Its neurotrophic activity is regulated by cysteine protease cathepsin X which cleaves the C-terminal end of the molecule. We have investigated the expression and colocalization of c-enolase and cathepsin X in brains of Tg2576 mice overexpressing amyloid precursor protein.In situ hybridization of c-enolase and cathepsin X revealed that mRNAs for both enzymes were expressed abundantly around amyloid plaques. Immunostaining demonstrated that the C-terminally cleaved form of c-enolase was present in the immediate plaque vicinity, whereas the intact form, exhibiting neurotrophic activity, was observed in microglia cells in close proximity to senile plaque. The upregulation of c-enolase in microglial cells in response to amyloid-b peptide (Ab) was confirmed in mouse microglial cell line EOC 13.31 and primary microglia and medium enriched with c-enolase proved to be neuroprotective against Ab toxicity; however, the effect was reversed by cathepsin X proteolytic activity. These results demonstrate an upregulation of c-enolase in microglia cells surrounding amyloid plaques in Tg2576 transgenic mice and demonstrate its neuroprotective role in amyloid-b-related neurodegeneration.

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“…The lysosomal cysteine protease, cathepsin Z, has been reported to be highly expressed in antigen presenting cells (APCs) [12, 13, 34]. This was confirmed in peritoneal and bone marrow-derived macrophages (pMØ, BMMØ), immortalized and bone marrow-derived dendritic cells (DC2.4, BMDC) and immortalized microglia (BV2) (Fig.…”

Section: Resultsmentioning

confidence: 80%

A role for cathepsin Z in neuroinflammation provides mechanistic support for an epigenetic risk factor in multiple sclerosis

Allan

Campden

Ewanchuk

et al. 2017

J Neuroinflammation

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BackgroundHypomethylation of the cathepsin Z locus has been proposed as an epigenetic risk factor for multiple sclerosis (MS). Cathepsin Z is a unique lysosomal cysteine cathepsin expressed primarily by antigen presenting cells. While cathepsin Z expression has been associated with neuroinflammatory disorders, a role for cathepsin Z in mediating neuroinflammation has not been previously established.MethodsExperimental autoimmune encephalomyelitis (EAE) was induced in both wildtype mice and mice deficient in cathepsin Z. The effects of cathepsin Z-deficiency on the processing and presentation of the autoantigen myelin oligodendrocyte glycoprotein, and on the production of IL-1β and IL-18 were determined in vitro from cells derived from wildtype and cathepsin Z-deficient mice. The effects of cathepsin Z-deficiency on CD4+ T cell activation, migration, and infiltration to the CNS were determined in vivo. Statistical analyses of parametric data were performed by one-way ANOVA followed by Tukey post-hoc tests, or by an unpaired Student’s t test. EAE clinical scoring was analyzed using the Mann–Whitney U test.ResultsWe showed that mice deficient in cathepsin Z have reduced neuroinflammation and dramatically lowered circulating levels of IL-1β during EAE. Deficiency in cathepsin Z did not impact either the processing or the presentation of MOG, or MOG- specific CD4+ T cell activation and trafficking. Consistently, we found that cathepsin Z-deficiency reduced the efficiency of antigen presenting cells to secrete IL-1β, which in turn reduced the ability of mice to generate Th17 responses—critical steps in the pathogenesis of EAE and MS.ConclusionTogether, these data support a novel role for cathepsin Z in the propagation of IL-1β-driven neuroinflammation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-017-0874-x) contains supplementary material, which is available to authorized users.

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Intra‐ versus extracellular effects of microglia‐derived cysteine proteases in a conditioned medium transfer model

Cited by 29 publications

References 53 publications

The microglial activation state regulates migration and roles of matrix-dissolving enzymes for invasion

The microglial activation state regulates migration and roles of matrix-dissolving enzymes for invasion

Neuroprotective role of γ‐enolase in microglia in a mouse model of Alzheimer's disease is regulated by cathepsin X

A role for cathepsin Z in neuroinflammation provides mechanistic support for an epigenetic risk factor in multiple sclerosis

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