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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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Related in: MedlinePlus

Inflammatory liver DCs in ob/ob mice. A: Hepatic mRNA was purified from 12-week-old ob/ob mice or 12-week-old nonobese littermate controls (NOB) and analyzed by qPCR for relative expression of cytokines. Shown is the fold increase in cytokine expression comparing RNA from ob/ob liver with NOB liver. Data are mean ± SEM of two separate experiments analyzing individual mice. B: Gradient-purified cells isolated from the livers of 12-week-old ob/ob mice or NOB mice were stained for surface markers against leukocyte subsets and analyzed by flow cytometry. **P ≤ 0.01, ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing individual mice. pDC, plasmacytoid DC. C: CD11c+ cells were purified by magnetic bead selection from gradient-enriched liver leukocytes from 12-week-old ob/ob mice or NOB mice. Cells were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for intracellular TNF and iNOS. Shown are flow cytometry analysis of cells and percentage of cells staining positive for TNF and iNOS. Data are mean ± SEM of two separate experiments analyzing individual mice. D: CD11c purified liver cells from ob/ob mice were stained for surface markers, costimulatory molecules, and MHC class II and analyzed by flow cytometry. E: CD11c+ DCs purified from livers of ob/ob mice were cultured for 48 h, stained for costimulatory molecules and MHC class II, and analyzed by flow cytometry. F: Livers from 12-week-old ob/ob mice or NOB mice were harvested, frozen in optimal cutting temperature media, sectioned, and stained with RelA (red) and CD11c (blue) antibodies. Arrows indicate nuclear RelA in CD11c+ cells. Original magnification ×25. (A high-quality digital representation of this figure is available in the online issue.)
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Figure 1: Inflammatory liver DCs in ob/ob mice. A: Hepatic mRNA was purified from 12-week-old ob/ob mice or 12-week-old nonobese littermate controls (NOB) and analyzed by qPCR for relative expression of cytokines. Shown is the fold increase in cytokine expression comparing RNA from ob/ob liver with NOB liver. Data are mean ± SEM of two separate experiments analyzing individual mice. B: Gradient-purified cells isolated from the livers of 12-week-old ob/ob mice or NOB mice were stained for surface markers against leukocyte subsets and analyzed by flow cytometry. **P ≤ 0.01, ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing individual mice. pDC, plasmacytoid DC. C: CD11c+ cells were purified by magnetic bead selection from gradient-enriched liver leukocytes from 12-week-old ob/ob mice or NOB mice. Cells were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for intracellular TNF and iNOS. Shown are flow cytometry analysis of cells and percentage of cells staining positive for TNF and iNOS. Data are mean ± SEM of two separate experiments analyzing individual mice. D: CD11c purified liver cells from ob/ob mice were stained for surface markers, costimulatory molecules, and MHC class II and analyzed by flow cytometry. E: CD11c+ DCs purified from livers of ob/ob mice were cultured for 48 h, stained for costimulatory molecules and MHC class II, and analyzed by flow cytometry. F: Livers from 12-week-old ob/ob mice or NOB mice were harvested, frozen in optimal cutting temperature media, sectioned, and stained with RelA (red) and CD11c (blue) antibodies. Arrows indicate nuclear RelA in CD11c+ cells. Original magnification ×25. (A high-quality digital representation of this figure is available in the online issue.)

Mentions: To determine the extent of inflammation in the livers of obese mice, we first examined proinflammatory cytokine expression by qPCR of RNA isolated from livers of 12-week-old ob/ob mice and age-matched ob/wt (NOB) livers. Expression of typical macrophage proinflammatory genes, including TNF (15-fold) and IL-6 (3-fold), was increased in obese relative to NOB mice (Fig. 1A). The T-cell cytokines IFN-γ (5-fold) and IL-17 (3-fold) were also increased in obese livers. There were no differences in the percentages of CD3+ T cells, CD19+ B cells, and pDCA1+ plasmacytoid DCs when comparing ob/ob and NOB mice. However, consistent with liver inflammation, a reduction in the proportion of CD3+NK1.1 NKT cells and an increase in proportion of MHC class II+ CD11b+ F4/80+ macrophages was observed in livers from ob/ob mice compared with age-matched NOB mice (Fig. 1B). These cells also expressed CD11c, which is broadly expressed by murine DC populations. We used CD11c immunoselection to isolate and further characterize this cell population from the liver. In particular, given their inflammatory environment, we sought other markers of DCs described recently to develop from inflammatory monocytes in response to infection in the liver and spleen, known as Tip-DCs because of their expression of TNF and iNOS (13).


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)

Inflammatory liver DCs in ob/ob mice. A: Hepatic mRNA was purified from 12-week-old ob/ob mice or 12-week-old nonobese littermate controls (NOB) and analyzed by qPCR for relative expression of cytokines. Shown is the fold increase in cytokine expression comparing RNA from ob/ob liver with NOB liver. Data are mean ± SEM of two separate experiments analyzing individual mice. B: Gradient-purified cells isolated from the livers of 12-week-old ob/ob mice or NOB mice were stained for surface markers against leukocyte subsets and analyzed by flow cytometry. **P ≤ 0.01, ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing individual mice. pDC, plasmacytoid DC. C: CD11c+ cells were purified by magnetic bead selection from gradient-enriched liver leukocytes from 12-week-old ob/ob mice or NOB mice. Cells were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for intracellular TNF and iNOS. Shown are flow cytometry analysis of cells and percentage of cells staining positive for TNF and iNOS. Data are mean ± SEM of two separate experiments analyzing individual mice. D: CD11c purified liver cells from ob/ob mice were stained for surface markers, costimulatory molecules, and MHC class II and analyzed by flow cytometry. E: CD11c+ DCs purified from livers of ob/ob mice were cultured for 48 h, stained for costimulatory molecules and MHC class II, and analyzed by flow cytometry. F: Livers from 12-week-old ob/ob mice or NOB mice were harvested, frozen in optimal cutting temperature media, sectioned, and stained with RelA (red) and CD11c (blue) antibodies. Arrows indicate nuclear RelA in CD11c+ cells. Original magnification ×25. (A high-quality digital representation of this figure is available in the online issue.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Figure 1: Inflammatory liver DCs in ob/ob mice. A: Hepatic mRNA was purified from 12-week-old ob/ob mice or 12-week-old nonobese littermate controls (NOB) and analyzed by qPCR for relative expression of cytokines. Shown is the fold increase in cytokine expression comparing RNA from ob/ob liver with NOB liver. Data are mean ± SEM of two separate experiments analyzing individual mice. B: Gradient-purified cells isolated from the livers of 12-week-old ob/ob mice or NOB mice were stained for surface markers against leukocyte subsets and analyzed by flow cytometry. **P ≤ 0.01, ***P ≤ 0.001 (one-way ANOVA followed by Bonferroni post hoc test). Data are mean ± SEM of two separate experiments analyzing individual mice. pDC, plasmacytoid DC. C: CD11c+ cells were purified by magnetic bead selection from gradient-enriched liver leukocytes from 12-week-old ob/ob mice or NOB mice. Cells were cultured with or without LPS for 24 h in the presence of brefeldin and then stained for intracellular TNF and iNOS. Shown are flow cytometry analysis of cells and percentage of cells staining positive for TNF and iNOS. Data are mean ± SEM of two separate experiments analyzing individual mice. D: CD11c purified liver cells from ob/ob mice were stained for surface markers, costimulatory molecules, and MHC class II and analyzed by flow cytometry. E: CD11c+ DCs purified from livers of ob/ob mice were cultured for 48 h, stained for costimulatory molecules and MHC class II, and analyzed by flow cytometry. F: Livers from 12-week-old ob/ob mice or NOB mice were harvested, frozen in optimal cutting temperature media, sectioned, and stained with RelA (red) and CD11c (blue) antibodies. Arrows indicate nuclear RelA in CD11c+ cells. Original magnification ×25. (A high-quality digital representation of this figure is available in the online issue.)
Mentions: To determine the extent of inflammation in the livers of obese mice, we first examined proinflammatory cytokine expression by qPCR of RNA isolated from livers of 12-week-old ob/ob mice and age-matched ob/wt (NOB) livers. Expression of typical macrophage proinflammatory genes, including TNF (15-fold) and IL-6 (3-fold), was increased in obese relative to NOB mice (Fig. 1A). The T-cell cytokines IFN-γ (5-fold) and IL-17 (3-fold) were also increased in obese livers. There were no differences in the percentages of CD3+ T cells, CD19+ B cells, and pDCA1+ plasmacytoid DCs when comparing ob/ob and NOB mice. However, consistent with liver inflammation, a reduction in the proportion of CD3+NK1.1 NKT cells and an increase in proportion of MHC class II+ CD11b+ F4/80+ macrophages was observed in livers from ob/ob mice compared with age-matched NOB mice (Fig. 1B). These cells also expressed CD11c, which is broadly expressed by murine DC populations. We used CD11c immunoselection to isolate and further characterize this cell population from the liver. In particular, given their inflammatory environment, we sought other markers of DCs described recently to develop from inflammatory monocytes in response to infection in the liver and spleen, known as Tip-DCs because of their expression of TNF and iNOS (13).

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