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Glioma-associated microglia/macrophages display an expression profile different from M1 and M2 polarization and highly express Gpnmb and Spp1.

Szulzewsky F, Pelz A, Feng X, Synowitz M, Markovic D, Langmann T, Holtman IR, Wang X, Eggen BJ, Boddeke HW, Hambardzumyan D, Wolf SA, Kettenmann H - PLoS ONE (2015)

Bottom Line: Around 1000 genes were more than 2-fold up- or downregulated in glioma-associated microglia/macrophages when compared to control cells.We confirmed in both models the unique glioma-associated microglia/macrophage phenotype including a mixture of M1 and M2a,b,c-specific genes.High expression of these genes has been associated with poor prognosis in human GBM, as indicated by patient survival data linked to gene expression data.

View Article: PubMed Central - PubMed

Affiliation: Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.

ABSTRACT
Malignant glioma belong to the most aggressive neoplasms in humans with no successful treatment available. Patients suffering from glioblastoma multiforme (GBM), the highest-grade glioma, have an average survival time of only around one year after diagnosis. Both microglia and peripheral macrophages/monocytes accumulate within and around glioma, but fail to exert effective anti-tumor activity and even support tumor growth. Here we use microarray analysis to compare the expression profiles of glioma-associated microglia/macrophages and naive control cells. Samples were generated from CD11b+ MACS-isolated cells from naïve and GL261-implanted C57BL/6 mouse brains. Around 1000 genes were more than 2-fold up- or downregulated in glioma-associated microglia/macrophages when compared to control cells. A comparison with published data sets of M1, M2a,b,c-polarized macrophages revealed a gene expression pattern that has only partial overlap with any of the M1 or M2 gene expression patterns. Samples for the qRT-PCR validation of selected M1 and M2a,b,c-specific genes were generated from two different glioma mouse models and isolated by flow cytometry to distinguish between resident microglia and invading macrophages. We confirmed in both models the unique glioma-associated microglia/macrophage phenotype including a mixture of M1 and M2a,b,c-specific genes. To validate the expression of these genes in human we MACS-isolated CD11b+ microglia/macrophages from GBM, lower grade brain tumors and control specimens. Apart from the M1/M2 gene analysis, we demonstrate that the expression of Gpnmb and Spp1 is highly upregulated in both murine and human glioma-associated microglia/macrophages. High expression of these genes has been associated with poor prognosis in human GBM, as indicated by patient survival data linked to gene expression data. We also show that microglia/macrophages are the predominant source of these transcripts in murine and human GBM. Our findings provide new potential targets for future anti-glioma therapy.

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High GPNMB and SPP1 expression is associated with worsened survival prognosis in human GBM patients.Data taken from the TCGA database, showing survival probability of glioma patients grouped according to high and low expression of our target genes GPNMB (A) and SPP1 (B). High expression of both genes has a negative effect on patient prognosis. Patients were in addition grouped into the four molecular subtypes (proneural, neural, mesenchymal, and classical). Low GPNMB expression seems to have the most severe effect on patient prognosis in the proneural subtype when including G-CIMP+ tumors, but no significant effect in the other subtypes. Low SPP1 expression seems to have the highest effect on patient prognosis in the neural and classical subtypes. Furthermore, both genes are differently regulated in the four subtypes (box plots in A and B) Significances for box plots: GPNMB: proneural GCIMP- (PG-) vs. proneural GCIMP+ (PG+) ***, PG- vs. mesenchymal (M) *** PG- vs. classical (C) **, PG+ vs. neural (N) ***, PG+ vs. M ***, PG+ vs. C **, N vs. M ***, N vs. C *, M vs. C ***. SPP1: PG- vs. M ***, PG+ vs. N ***, PG+ vs. M ***, C vs. M ***.*, p<0.05; **, p<0.01; ***, p<0.001
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pone.0116644.g009: High GPNMB and SPP1 expression is associated with worsened survival prognosis in human GBM patients.Data taken from the TCGA database, showing survival probability of glioma patients grouped according to high and low expression of our target genes GPNMB (A) and SPP1 (B). High expression of both genes has a negative effect on patient prognosis. Patients were in addition grouped into the four molecular subtypes (proneural, neural, mesenchymal, and classical). Low GPNMB expression seems to have the most severe effect on patient prognosis in the proneural subtype when including G-CIMP+ tumors, but no significant effect in the other subtypes. Low SPP1 expression seems to have the highest effect on patient prognosis in the neural and classical subtypes. Furthermore, both genes are differently regulated in the four subtypes (box plots in A and B) Significances for box plots: GPNMB: proneural GCIMP- (PG-) vs. proneural GCIMP+ (PG+) ***, PG- vs. mesenchymal (M) *** PG- vs. classical (C) **, PG+ vs. neural (N) ***, PG+ vs. M ***, PG+ vs. C **, N vs. M ***, N vs. C *, M vs. C ***. SPP1: PG- vs. M ***, PG+ vs. N ***, PG+ vs. M ***, C vs. M ***.*, p<0.05; **, p<0.01; ***, p<0.001

Mentions: We used the cBioPortal database (http://www.cbioportal.org/public-portal/), to access TCGA data which links gene expression data to patient data, to investigate the effect of GPNMB and SPP1 expression on patient prognosis [36,37]. We grouped patients into low and high expression (gene expression lower than the negative standard deviation or higher than the positive standard deviation, respectively) and determined the overall survival for these patients. High expression of each gene has a negative effect on patient prognosis. Median survival was 19.77 months (low GPNMB expression) vs. 12.92 months (high GPNMB expression) and 15.31 months (low SPP1 expression) vs. 8.82 months (high SPP1 expression) (Fig. 9). This dataset also included G-CIMP+ tumors that are mostly proneural subtype tumors and generally have a better overall survival prognosis when compared to G-CIMP- tumors. We excluded these G-CIMP+ tumors from our analysis and reanalyzed the data. Most G-CIMP+ tumors exhibited a low expression of both, GPNMB and SPP1. Accordingly, the overall survival prediction for tumors with low expression of either GPNMB or SPP1 was less favorable after removing G-CIMP+ tumors from the analysis. Median overall survival for GBM with low SPP1 or GPNMB expression was 14.16 months (low SPP1 expression including G-CIMP+ tumors) vs. 12.56 months (low SPP1 expression excluding G-CIMP+ tumors) and 17.7 months (low GPNMB expression including G-CIMP+ tumors) vs. 14.82 months (low GPNMB expression excluding G-CIMP+ tumors). We also plotted the overall survival of patients with intermediate expression of each gene (S4 Fig.). Patients with high and intermediate GPNMB expression have a similar overall survival prognosis, whereas patients with low GPNMB expression have a significantly better prognosis. Median survival excluding G-CIMP+ tumors was 10.39 months (high GPNMB expression), 9.84 months (intermediate expression), and 14.82 months (low expression). In contrast, the survival prognosis of patients with intermediate SPP1 expression is in between of patients with low and high SPP1 expression. Median survival excluding G-CIMP+ tumors was 7.29 months (high SPP1 expression), 10.49 months (intermediate expression), and 12.56 months (low expression).


Glioma-associated microglia/macrophages display an expression profile different from M1 and M2 polarization and highly express Gpnmb and Spp1.

Szulzewsky F, Pelz A, Feng X, Synowitz M, Markovic D, Langmann T, Holtman IR, Wang X, Eggen BJ, Boddeke HW, Hambardzumyan D, Wolf SA, Kettenmann H - PLoS ONE (2015)

High GPNMB and SPP1 expression is associated with worsened survival prognosis in human GBM patients.Data taken from the TCGA database, showing survival probability of glioma patients grouped according to high and low expression of our target genes GPNMB (A) and SPP1 (B). High expression of both genes has a negative effect on patient prognosis. Patients were in addition grouped into the four molecular subtypes (proneural, neural, mesenchymal, and classical). Low GPNMB expression seems to have the most severe effect on patient prognosis in the proneural subtype when including G-CIMP+ tumors, but no significant effect in the other subtypes. Low SPP1 expression seems to have the highest effect on patient prognosis in the neural and classical subtypes. Furthermore, both genes are differently regulated in the four subtypes (box plots in A and B) Significances for box plots: GPNMB: proneural GCIMP- (PG-) vs. proneural GCIMP+ (PG+) ***, PG- vs. mesenchymal (M) *** PG- vs. classical (C) **, PG+ vs. neural (N) ***, PG+ vs. M ***, PG+ vs. C **, N vs. M ***, N vs. C *, M vs. C ***. SPP1: PG- vs. M ***, PG+ vs. N ***, PG+ vs. M ***, C vs. M ***.*, p<0.05; **, p<0.01; ***, p<0.001
© Copyright Policy
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pone.0116644.g009: High GPNMB and SPP1 expression is associated with worsened survival prognosis in human GBM patients.Data taken from the TCGA database, showing survival probability of glioma patients grouped according to high and low expression of our target genes GPNMB (A) and SPP1 (B). High expression of both genes has a negative effect on patient prognosis. Patients were in addition grouped into the four molecular subtypes (proneural, neural, mesenchymal, and classical). Low GPNMB expression seems to have the most severe effect on patient prognosis in the proneural subtype when including G-CIMP+ tumors, but no significant effect in the other subtypes. Low SPP1 expression seems to have the highest effect on patient prognosis in the neural and classical subtypes. Furthermore, both genes are differently regulated in the four subtypes (box plots in A and B) Significances for box plots: GPNMB: proneural GCIMP- (PG-) vs. proneural GCIMP+ (PG+) ***, PG- vs. mesenchymal (M) *** PG- vs. classical (C) **, PG+ vs. neural (N) ***, PG+ vs. M ***, PG+ vs. C **, N vs. M ***, N vs. C *, M vs. C ***. SPP1: PG- vs. M ***, PG+ vs. N ***, PG+ vs. M ***, C vs. M ***.*, p<0.05; **, p<0.01; ***, p<0.001
Mentions: We used the cBioPortal database (http://www.cbioportal.org/public-portal/), to access TCGA data which links gene expression data to patient data, to investigate the effect of GPNMB and SPP1 expression on patient prognosis [36,37]. We grouped patients into low and high expression (gene expression lower than the negative standard deviation or higher than the positive standard deviation, respectively) and determined the overall survival for these patients. High expression of each gene has a negative effect on patient prognosis. Median survival was 19.77 months (low GPNMB expression) vs. 12.92 months (high GPNMB expression) and 15.31 months (low SPP1 expression) vs. 8.82 months (high SPP1 expression) (Fig. 9). This dataset also included G-CIMP+ tumors that are mostly proneural subtype tumors and generally have a better overall survival prognosis when compared to G-CIMP- tumors. We excluded these G-CIMP+ tumors from our analysis and reanalyzed the data. Most G-CIMP+ tumors exhibited a low expression of both, GPNMB and SPP1. Accordingly, the overall survival prediction for tumors with low expression of either GPNMB or SPP1 was less favorable after removing G-CIMP+ tumors from the analysis. Median overall survival for GBM with low SPP1 or GPNMB expression was 14.16 months (low SPP1 expression including G-CIMP+ tumors) vs. 12.56 months (low SPP1 expression excluding G-CIMP+ tumors) and 17.7 months (low GPNMB expression including G-CIMP+ tumors) vs. 14.82 months (low GPNMB expression excluding G-CIMP+ tumors). We also plotted the overall survival of patients with intermediate expression of each gene (S4 Fig.). Patients with high and intermediate GPNMB expression have a similar overall survival prognosis, whereas patients with low GPNMB expression have a significantly better prognosis. Median survival excluding G-CIMP+ tumors was 10.39 months (high GPNMB expression), 9.84 months (intermediate expression), and 14.82 months (low expression). In contrast, the survival prognosis of patients with intermediate SPP1 expression is in between of patients with low and high SPP1 expression. Median survival excluding G-CIMP+ tumors was 7.29 months (high SPP1 expression), 10.49 months (intermediate expression), and 12.56 months (low expression).

Bottom Line: Around 1000 genes were more than 2-fold up- or downregulated in glioma-associated microglia/macrophages when compared to control cells.We confirmed in both models the unique glioma-associated microglia/macrophage phenotype including a mixture of M1 and M2a,b,c-specific genes.High expression of these genes has been associated with poor prognosis in human GBM, as indicated by patient survival data linked to gene expression data.

View Article: PubMed Central - PubMed

Affiliation: Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.

ABSTRACT
Malignant glioma belong to the most aggressive neoplasms in humans with no successful treatment available. Patients suffering from glioblastoma multiforme (GBM), the highest-grade glioma, have an average survival time of only around one year after diagnosis. Both microglia and peripheral macrophages/monocytes accumulate within and around glioma, but fail to exert effective anti-tumor activity and even support tumor growth. Here we use microarray analysis to compare the expression profiles of glioma-associated microglia/macrophages and naive control cells. Samples were generated from CD11b+ MACS-isolated cells from naïve and GL261-implanted C57BL/6 mouse brains. Around 1000 genes were more than 2-fold up- or downregulated in glioma-associated microglia/macrophages when compared to control cells. A comparison with published data sets of M1, M2a,b,c-polarized macrophages revealed a gene expression pattern that has only partial overlap with any of the M1 or M2 gene expression patterns. Samples for the qRT-PCR validation of selected M1 and M2a,b,c-specific genes were generated from two different glioma mouse models and isolated by flow cytometry to distinguish between resident microglia and invading macrophages. We confirmed in both models the unique glioma-associated microglia/macrophage phenotype including a mixture of M1 and M2a,b,c-specific genes. To validate the expression of these genes in human we MACS-isolated CD11b+ microglia/macrophages from GBM, lower grade brain tumors and control specimens. Apart from the M1/M2 gene analysis, we demonstrate that the expression of Gpnmb and Spp1 is highly upregulated in both murine and human glioma-associated microglia/macrophages. High expression of these genes has been associated with poor prognosis in human GBM, as indicated by patient survival data linked to gene expression data. We also show that microglia/macrophages are the predominant source of these transcripts in murine and human GBM. Our findings provide new potential targets for future anti-glioma therapy.

Show MeSH
Related in: MedlinePlus