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Targeting curcusomes to inflammatory dendritic cells inhibits NF-κB and improves insulin resistance in obese mice.

Yekollu SK, Thomas R, O'Sullivan B - Diabetes (2011)

Bottom Line: Phagocytic myeloid cells infiltrating the liver in ob/ob mice had the phenotypic characteristics of Tip-DCs that arise from monocyte precursors in the liver and spleen after infection.Targeting Tip-DCs and ATMs with curcusomes in ob/ob mice reduced NF-κB/RelA DNA binding activity, reduced TNF, and enhanced interleukin-4 production.Targeting inflammatory DCs is a novel approach for type 2 diabetes treatment.

View Article: PubMed Central - PubMed

Affiliation: University of Queensland Diamantina Institute, Woolloongabba, Queensland, Australia.

ABSTRACT

Objective: To determine whether and by what mechanism systemic delivery of curcumin-containing liposomes improves insulin resistance in the leptin deficient (ob/ob) mouse model of insulin resistance.

Research design and methods: Insulin resistant ob/ob mice with steatosis were injected intraperitoneally with liposome nanoparticles, entrapping the nuclear factor-κB (NF-κB) inhibitor curcumin (curcusomes), and uptake in liver and adipose tissue was determined by flow cytometry. The effects of curcusomes on macrophage NF-κB activation and cytokine production were assessed. Transfer experiments determined the role of hepatic tumor necrosis factor (TNF)/inducible nitric oxide synthase-producing dendritic cells (Tip-DCs) and adipose tissue macrophages (ATMs) in inflammation-induced insulin resistance, determined by homeostatic assessment of insulin resistance.

Results: Phagocytic myeloid cells infiltrating the liver in ob/ob mice had the phenotypic characteristics of Tip-DCs that arise from monocyte precursors in the liver and spleen after infection. Targeting Tip-DCs and ATMs with curcusomes in ob/ob mice reduced NF-κB/RelA DNA binding activity, reduced TNF, and enhanced interleukin-4 production. Curcusomes improved peripheral insulin resistance.

Conclusions: Both hepatic Tip-DCs and ATMs contribute to insulin resistance in ob/ob mice. Curcusome nanoparticles inhibit proinflammatory pathways in hepatic Tip-DCs and ATMs and reverse insulin resistance. Targeting inflammatory DCs is a novel approach for type 2 diabetes treatment.

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Curcusomes inhibit oxidative burst, cytokine production, and NF-κB in peritoneal macrophages from ob/ob mice. A: Cells isolated from peritoneal exudates from ob/ob mice were cultured for 30 min with or without zymosan in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Oxidative burst was measured by chemiluminescence and was expressed as relative light units (RLUs). *P ≤ 0.05 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. B: Cells isolated from peritoneal exudates from ob/ob mice were cultured in media for 6 h with or without LPS in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Shown is IL-6 concentration in supernatants measured by cytokine bead array. ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and 24 h later, cells from peritoneal exudates were harvested and stained for MHC class II and B220. Shown is DiI uptake by both macrophages and B cells. Data representative of five separate experiments. D: Cells isolated from peritoneal exudates from ob/ob mice injected intraperitoneally with DiI-labeled empty liposomes or curcumin liposomes were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for surface B220 and intracellular IL-6. Shown are flow cytometry plots with B220-negative macrophages as the main source of IL-6. Data representative of two separate experiments. E: Cells in C were adhered to chamber slides for 1 h in the presence of LPS and then stained for RelA (green) or p50 (green), CD11c (blue), and DAPI (cyan). DiI staining is shown in red; images acquired by immunofluorescence microscopy. Original magnification ×25. Data representative of three separate experiments. F: Nuclear extracts from cells in C were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. Ip, intraperitoneally. (A high-quality digital representation of this figure is available in the online issue.)
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Figure 2: Curcusomes inhibit oxidative burst, cytokine production, and NF-κB in peritoneal macrophages from ob/ob mice. A: Cells isolated from peritoneal exudates from ob/ob mice were cultured for 30 min with or without zymosan in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Oxidative burst was measured by chemiluminescence and was expressed as relative light units (RLUs). *P ≤ 0.05 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. B: Cells isolated from peritoneal exudates from ob/ob mice were cultured in media for 6 h with or without LPS in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Shown is IL-6 concentration in supernatants measured by cytokine bead array. ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and 24 h later, cells from peritoneal exudates were harvested and stained for MHC class II and B220. Shown is DiI uptake by both macrophages and B cells. Data representative of five separate experiments. D: Cells isolated from peritoneal exudates from ob/ob mice injected intraperitoneally with DiI-labeled empty liposomes or curcumin liposomes were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for surface B220 and intracellular IL-6. Shown are flow cytometry plots with B220-negative macrophages as the main source of IL-6. Data representative of two separate experiments. E: Cells in C were adhered to chamber slides for 1 h in the presence of LPS and then stained for RelA (green) or p50 (green), CD11c (blue), and DAPI (cyan). DiI staining is shown in red; images acquired by immunofluorescence microscopy. Original magnification ×25. Data representative of three separate experiments. F: Nuclear extracts from cells in C were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. Ip, intraperitoneally. (A high-quality digital representation of this figure is available in the online issue.)

Mentions: Curcusomes target and inhibit proinflammatory pathways of phagocytic antigen-presenting cells, including macrophages and DCs in healthy mice or mice with inflammatory arthritis (10). To test whether curcusomes inhibited inflammatory function of macrophages in the setting of obesity, peritoneal macrophages were isolated from ob/ob mice and cultured with either curcusomes or empty liposomes in the presence or absence of opsonized zymosan to induce an oxidative burst. In vitro, curcusomes—but not empty liposomes—inhibited the oxidative burst, indicating an antioxidant effect (Fig. 2A). Next, their effect on proinflammatory cytokine production was examined in macrophages cultured with LPS for 6 h in the presence or absence of curcusomes and free curcumin (Fig. 2B). Consistent with an anti-inflammatory effect, curcusomes or soluble curcumin inhibited LPS-induced IL-6 production in supernatants from macrophage cultures. These data indicate that curcusomes inhibit the oxidative burst and production of proinflammatory cytokines by macrophages in response to inflammatory triggers in vitro.


Targeting curcusomes to inflammatory dendritic cells inhibits NF-κB and improves insulin resistance in obese mice.

Yekollu SK, Thomas R, O'Sullivan B - Diabetes (2011)

Curcusomes inhibit oxidative burst, cytokine production, and NF-κB in peritoneal macrophages from ob/ob mice. A: Cells isolated from peritoneal exudates from ob/ob mice were cultured for 30 min with or without zymosan in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Oxidative burst was measured by chemiluminescence and was expressed as relative light units (RLUs). *P ≤ 0.05 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. B: Cells isolated from peritoneal exudates from ob/ob mice were cultured in media for 6 h with or without LPS in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Shown is IL-6 concentration in supernatants measured by cytokine bead array. ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and 24 h later, cells from peritoneal exudates were harvested and stained for MHC class II and B220. Shown is DiI uptake by both macrophages and B cells. Data representative of five separate experiments. D: Cells isolated from peritoneal exudates from ob/ob mice injected intraperitoneally with DiI-labeled empty liposomes or curcumin liposomes were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for surface B220 and intracellular IL-6. Shown are flow cytometry plots with B220-negative macrophages as the main source of IL-6. Data representative of two separate experiments. E: Cells in C were adhered to chamber slides for 1 h in the presence of LPS and then stained for RelA (green) or p50 (green), CD11c (blue), and DAPI (cyan). DiI staining is shown in red; images acquired by immunofluorescence microscopy. Original magnification ×25. Data representative of three separate experiments. F: Nuclear extracts from cells in C were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. Ip, intraperitoneally. (A high-quality digital representation of this figure is available in the online issue.)
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Related In: Results  -  Collection

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Figure 2: Curcusomes inhibit oxidative burst, cytokine production, and NF-κB in peritoneal macrophages from ob/ob mice. A: Cells isolated from peritoneal exudates from ob/ob mice were cultured for 30 min with or without zymosan in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Oxidative burst was measured by chemiluminescence and was expressed as relative light units (RLUs). *P ≤ 0.05 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. B: Cells isolated from peritoneal exudates from ob/ob mice were cultured in media for 6 h with or without LPS in the presence of 1 μg/mL final concentration of empty liposomes or curcusomes. Shown is IL-6 concentration in supernatants measured by cytokine bead array. ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing peritoneal exudates pooled from three mice. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and 24 h later, cells from peritoneal exudates were harvested and stained for MHC class II and B220. Shown is DiI uptake by both macrophages and B cells. Data representative of five separate experiments. D: Cells isolated from peritoneal exudates from ob/ob mice injected intraperitoneally with DiI-labeled empty liposomes or curcumin liposomes were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for surface B220 and intracellular IL-6. Shown are flow cytometry plots with B220-negative macrophages as the main source of IL-6. Data representative of two separate experiments. E: Cells in C were adhered to chamber slides for 1 h in the presence of LPS and then stained for RelA (green) or p50 (green), CD11c (blue), and DAPI (cyan). DiI staining is shown in red; images acquired by immunofluorescence microscopy. Original magnification ×25. Data representative of three separate experiments. F: Nuclear extracts from cells in C were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. Ip, intraperitoneally. (A high-quality digital representation of this figure is available in the online issue.)
Mentions: Curcusomes target and inhibit proinflammatory pathways of phagocytic antigen-presenting cells, including macrophages and DCs in healthy mice or mice with inflammatory arthritis (10). To test whether curcusomes inhibited inflammatory function of macrophages in the setting of obesity, peritoneal macrophages were isolated from ob/ob mice and cultured with either curcusomes or empty liposomes in the presence or absence of opsonized zymosan to induce an oxidative burst. In vitro, curcusomes—but not empty liposomes—inhibited the oxidative burst, indicating an antioxidant effect (Fig. 2A). Next, their effect on proinflammatory cytokine production was examined in macrophages cultured with LPS for 6 h in the presence or absence of curcusomes and free curcumin (Fig. 2B). Consistent with an anti-inflammatory effect, curcusomes or soluble curcumin inhibited LPS-induced IL-6 production in supernatants from macrophage cultures. These data indicate that curcusomes inhibit the oxidative burst and production of proinflammatory cytokines by macrophages in response to inflammatory triggers in vitro.

Bottom Line: Phagocytic myeloid cells infiltrating the liver in ob/ob mice had the phenotypic characteristics of Tip-DCs that arise from monocyte precursors in the liver and spleen after infection.Targeting Tip-DCs and ATMs with curcusomes in ob/ob mice reduced NF-κB/RelA DNA binding activity, reduced TNF, and enhanced interleukin-4 production.Targeting inflammatory DCs is a novel approach for type 2 diabetes treatment.

View Article: PubMed Central - PubMed

Affiliation: University of Queensland Diamantina Institute, Woolloongabba, Queensland, Australia.

ABSTRACT

Objective: To determine whether and by what mechanism systemic delivery of curcumin-containing liposomes improves insulin resistance in the leptin deficient (ob/ob) mouse model of insulin resistance.

Research design and methods: Insulin resistant ob/ob mice with steatosis were injected intraperitoneally with liposome nanoparticles, entrapping the nuclear factor-κB (NF-κB) inhibitor curcumin (curcusomes), and uptake in liver and adipose tissue was determined by flow cytometry. The effects of curcusomes on macrophage NF-κB activation and cytokine production were assessed. Transfer experiments determined the role of hepatic tumor necrosis factor (TNF)/inducible nitric oxide synthase-producing dendritic cells (Tip-DCs) and adipose tissue macrophages (ATMs) in inflammation-induced insulin resistance, determined by homeostatic assessment of insulin resistance.

Results: Phagocytic myeloid cells infiltrating the liver in ob/ob mice had the phenotypic characteristics of Tip-DCs that arise from monocyte precursors in the liver and spleen after infection. Targeting Tip-DCs and ATMs with curcusomes in ob/ob mice reduced NF-κB/RelA DNA binding activity, reduced TNF, and enhanced interleukin-4 production. Curcusomes improved peripheral insulin resistance.

Conclusions: Both hepatic Tip-DCs and ATMs contribute to insulin resistance in ob/ob mice. Curcusome nanoparticles inhibit proinflammatory pathways in hepatic Tip-DCs and ATMs and reverse insulin resistance. Targeting inflammatory DCs is a novel approach for type 2 diabetes treatment.

Show MeSH
Related in: MedlinePlus