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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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In vivo delivery of curcusomes inhibits adipose tissue inflammatory DC nuclear RelA and promotes insulin sensitivity. A: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and gradient-purified cells were harvested at 24 and 72 h and stained for MHC class II and CD11c. Shown are the percentages of CD11c+ cells that are DiI+. Data are mean ± SEM of two separate experiments. B: Nuclear extracts from CD11c+ ATM isolated from ob/ob mice injected with or without curcusomes for 24 h were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes for 72 h and then adipose tissue was harvested, frozen in optimal cutting temperature media, sectioned, and stained with CD11b (blue) or F4/80 (green) and CD11c (blue) antibodies. DiI staining is indicated in red; images analyzed by immunofluorescence microscopy. Original magnification ×25. D: GTT from NOB mice injected intravenously with 1 × 106 F4/80+ DCs from adipose tissue or liver tissue from ob/ob mice treated with or empty liposomes or curcusomes for 24 h. (A high-quality digital representation of this figure is available in the online issue.)
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Figure 6: In vivo delivery of curcusomes inhibits adipose tissue inflammatory DC nuclear RelA and promotes insulin sensitivity. A: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and gradient-purified cells were harvested at 24 and 72 h and stained for MHC class II and CD11c. Shown are the percentages of CD11c+ cells that are DiI+. Data are mean ± SEM of two separate experiments. B: Nuclear extracts from CD11c+ ATM isolated from ob/ob mice injected with or without curcusomes for 24 h were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes for 72 h and then adipose tissue was harvested, frozen in optimal cutting temperature media, sectioned, and stained with CD11b (blue) or F4/80 (green) and CD11c (blue) antibodies. DiI staining is indicated in red; images analyzed by immunofluorescence microscopy. Original magnification ×25. D: GTT from NOB mice injected intravenously with 1 × 106 F4/80+ DCs from adipose tissue or liver tissue from ob/ob mice treated with or empty liposomes or curcusomes for 24 h. (A high-quality digital representation of this figure is available in the online issue.)

Mentions: Given that curcusomes are widely taken up and inhibitory of inflammatory macrophages and DCs in ob/ob tissues, we also examined their uptake and effects on ATMs. We injected curcusomes and examined uptake by ATMs at 24 and 72 h by flow cytometry (Fig. 6A). Of ATMs, 35% were DiI+ and DiI uptake was maximal at 72 h, similar to the levels of uptake seen in the liver. Moreover, the cells that took up curcusomes were CD11b+F4/80+CD11c+ macrophages similar to liver Tip-DCs and were similarly located in “crown-like” structures surrounding large fat-laden adipocytes (Fig. 6B). Isolated adipose tissue inflammatory DCs demonstrated nuclear staining for p65/RelA and p50 but cytoplasmic staining for c-Rel, p52, and RelB, indicating activation of the classical but not alternate NF-κB pathway (Supplementary Fig. 2). Nuclear p65/RelA staining was reduced in ATMs isolated from adipose tissue of ob/ob mice treated with curcusomes for 72 h (Fig. 6C).


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)

In vivo delivery of curcusomes inhibits adipose tissue inflammatory DC nuclear RelA and promotes insulin sensitivity. A: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and gradient-purified cells were harvested at 24 and 72 h and stained for MHC class II and CD11c. Shown are the percentages of CD11c+ cells that are DiI+. Data are mean ± SEM of two separate experiments. B: Nuclear extracts from CD11c+ ATM isolated from ob/ob mice injected with or without curcusomes for 24 h were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes for 72 h and then adipose tissue was harvested, frozen in optimal cutting temperature media, sectioned, and stained with CD11b (blue) or F4/80 (green) and CD11c (blue) antibodies. DiI staining is indicated in red; images analyzed by immunofluorescence microscopy. Original magnification ×25. D: GTT from NOB mice injected intravenously with 1 × 106 F4/80+ DCs from adipose tissue or liver tissue from ob/ob mice treated with or empty liposomes or curcusomes for 24 h. (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 6: In vivo delivery of curcusomes inhibits adipose tissue inflammatory DC nuclear RelA and promotes insulin sensitivity. A: Ob/ob mice were injected intraperitoneally with DiI-curcusomes, and gradient-purified cells were harvested at 24 and 72 h and stained for MHC class II and CD11c. Shown are the percentages of CD11c+ cells that are DiI+. Data are mean ± SEM of two separate experiments. B: Nuclear extracts from CD11c+ ATM isolated from ob/ob mice injected with or without curcusomes for 24 h were analyzed for DNA binding of RelA by chemiluminescence. Shown is the mean of duplicates from two separate experiments. C: Ob/ob mice were injected intraperitoneally with DiI-curcusomes for 72 h and then adipose tissue was harvested, frozen in optimal cutting temperature media, sectioned, and stained with CD11b (blue) or F4/80 (green) and CD11c (blue) antibodies. DiI staining is indicated in red; images analyzed by immunofluorescence microscopy. Original magnification ×25. D: GTT from NOB mice injected intravenously with 1 × 106 F4/80+ DCs from adipose tissue or liver tissue from ob/ob mice treated with or empty liposomes or curcusomes for 24 h. (A high-quality digital representation of this figure is available in the online issue.)
Mentions: Given that curcusomes are widely taken up and inhibitory of inflammatory macrophages and DCs in ob/ob tissues, we also examined their uptake and effects on ATMs. We injected curcusomes and examined uptake by ATMs at 24 and 72 h by flow cytometry (Fig. 6A). Of ATMs, 35% were DiI+ and DiI uptake was maximal at 72 h, similar to the levels of uptake seen in the liver. Moreover, the cells that took up curcusomes were CD11b+F4/80+CD11c+ macrophages similar to liver Tip-DCs and were similarly located in “crown-like” structures surrounding large fat-laden adipocytes (Fig. 6B). Isolated adipose tissue inflammatory DCs demonstrated nuclear staining for p65/RelA and p50 but cytoplasmic staining for c-Rel, p52, and RelB, indicating activation of the classical but not alternate NF-κB pathway (Supplementary Fig. 2). Nuclear p65/RelA staining was reduced in ATMs isolated from adipose tissue of ob/ob mice treated with curcusomes for 72 h (Fig. 6C).

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