Limits...
Aberrant accumulation of undifferentiated myeloid cells in the adipose tissue of CCR2-deficient mice delays improvements in insulin sensitivity.

Gutierrez DA, Kennedy A, Orr JS, Anderson EK, Webb CD, Gerrald WK, Hasty AH - Diabetes (2011)

Bottom Line: Adipose tissue myeloid populations, degree of inflammation, glucose tolerance, and insulin sensitivity were assessed.Gene expression and histological analysis of the CD11b(lo)F4/80(lo) cells indicated that they are a unique undifferentiated monocytic inflammatory population.The discovery of this novel adipose tissue monocytic cell population provides advances toward understanding the pleiotropic role of CCR2 in monocyte/macrophage accumulation and regulation of adipose tissue inflammation.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.

ABSTRACT

Objective: Mice with CCR2 deficiency are protected from insulin resistance but only after long periods of high-fat diet (HFD) feeding, despite the virtual absence of circulating inflammatory monocytes. We performed a time course study in mice with hematopoietic and global CCR2 deficiency to determine adipose tissue-specific mechanisms for the delayed impact of CCR2 deficiency on insulin resistance.

Research design and methods: Mice with global or hematopoietic CCR2 deficiency (CCR2(-/-) and BM-CCR2(-/-), respectively) and wild-type controls (CCR2(+/+) and BM-CCR2(+/+), respectively) were placed on an HFD for 6, 12, and 20 weeks. Adipose tissue myeloid populations, degree of inflammation, glucose tolerance, and insulin sensitivity were assessed.

Results: Flow cytometry analysis showed that two different populations of F4/80(+) myeloid cells (CD11b(lo)F4/80(lo) and CD11b(hi)F4/80(hi)) accumulated in the adipose tissue of CCR2(-/-) and BM-CCR2(-/-) mice after 6 and 12 weeks of HFD feeding, whereas only the CD11b(hi)F4/80(hi) population was detected in the CCR2(+/+) and BM-CCR2(+/+) controls. After 20 weeks of HFD feeding, the CD11b(lo)F4/80(lo) cells were no longer present in the adipose tissue of CCR2(-/-) mice, and only then were improvements in adipose tissue inflammation detected. Gene expression and histological analysis of the CD11b(lo)F4/80(lo) cells indicated that they are a unique undifferentiated monocytic inflammatory population. The CD11b(lo)F4/80(lo) cells are transiently found in wild-type mice, but CCR2 deficiency leads to the aberrant accumulation of these cells in adipose tissue.

Conclusions: The discovery of this novel adipose tissue monocytic cell population provides advances toward understanding the pleiotropic role of CCR2 in monocyte/macrophage accumulation and regulation of adipose tissue inflammation.

Show MeSH

Related in: MedlinePlus

A unique F4/80lo myeloid population accumulates in the SVF of the adipose tissue of BM-CCR2−/− mice. SVCs isolated from BM-CCR2+/+ and BM-CCR2−/− mice were analyzed by flow cytometry. Representative flow cytometry histogram of F4/80-expressing populations in a BM-CCR2+/+ mouse (A) and in a BM-CCR2−/− mouse (B) gated on all live cells. C: Quantification of F4/80lo vs. F4/80hi cell percentages after 6, 12, and 20 weeks of an HFD in the BM-CCR2−/− mice (mean ± SEM; n = 3–5). D–F: RNA was isolated from adipose tissue and used for gene expression analysis by real-time RT-PCR. The mRNA expression of Mpo, Il8rb, Cxcl2, and Cxcl1 was assessed after 6 (D), 12 (E), and 20 (F) weeks of HFD feeding and plotted as expression relative to the BM-CCR2+/+ group of each time point (mean ± SEM; n = 7–10 mice per group). *P < 0.05 compared with the BM-CCR2+/+ group. **P < 0.01 compared with the BM-CCR2+/+ group. ***P < 0.001 compared with the BM-CCR2+/+ group.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3198070&req=5

Figure 3: A unique F4/80lo myeloid population accumulates in the SVF of the adipose tissue of BM-CCR2−/− mice. SVCs isolated from BM-CCR2+/+ and BM-CCR2−/− mice were analyzed by flow cytometry. Representative flow cytometry histogram of F4/80-expressing populations in a BM-CCR2+/+ mouse (A) and in a BM-CCR2−/− mouse (B) gated on all live cells. C: Quantification of F4/80lo vs. F4/80hi cell percentages after 6, 12, and 20 weeks of an HFD in the BM-CCR2−/− mice (mean ± SEM; n = 3–5). D–F: RNA was isolated from adipose tissue and used for gene expression analysis by real-time RT-PCR. The mRNA expression of Mpo, Il8rb, Cxcl2, and Cxcl1 was assessed after 6 (D), 12 (E), and 20 (F) weeks of HFD feeding and plotted as expression relative to the BM-CCR2+/+ group of each time point (mean ± SEM; n = 7–10 mice per group). *P < 0.05 compared with the BM-CCR2+/+ group. **P < 0.01 compared with the BM-CCR2+/+ group. ***P < 0.001 compared with the BM-CCR2+/+ group.

Mentions: Based on our observation that there were no changes in immune infiltration in adipose tissue after 6 and 12 weeks of HFD feeding despite the dramatic reduction in circulating inflammatory cells, we sought to further characterize the macrophages in adipose tissue by flow cytometry. To this end, we performed careful evaluation of the F4/80+ cells within adipose tissue. Based on our gating strategy, the BM-CCR2+/+ mice contained the expected F4/80− and F4/80hi populations (Fig. 3A). Interestingly, the BM-CCR2−/− mice accumulated two discrete myeloid populations in their adipose tissue: F4/80lo and F4/80hi (Fig. 3B). The discrete F4/80lo population was observed in the SVF of the BM-CCR2−/− at the 6-week (Fig. 3B and C) and 12-week (Fig. 3C and Supplementary Fig. 8B) time points but was no longer detected after 20 weeks of HFD feeding (Fig. 3C and Supplementary Fig. 8D).


Aberrant accumulation of undifferentiated myeloid cells in the adipose tissue of CCR2-deficient mice delays improvements in insulin sensitivity.

Gutierrez DA, Kennedy A, Orr JS, Anderson EK, Webb CD, Gerrald WK, Hasty AH - Diabetes (2011)

A unique F4/80lo myeloid population accumulates in the SVF of the adipose tissue of BM-CCR2−/− mice. SVCs isolated from BM-CCR2+/+ and BM-CCR2−/− mice were analyzed by flow cytometry. Representative flow cytometry histogram of F4/80-expressing populations in a BM-CCR2+/+ mouse (A) and in a BM-CCR2−/− mouse (B) gated on all live cells. C: Quantification of F4/80lo vs. F4/80hi cell percentages after 6, 12, and 20 weeks of an HFD in the BM-CCR2−/− mice (mean ± SEM; n = 3–5). D–F: RNA was isolated from adipose tissue and used for gene expression analysis by real-time RT-PCR. The mRNA expression of Mpo, Il8rb, Cxcl2, and Cxcl1 was assessed after 6 (D), 12 (E), and 20 (F) weeks of HFD feeding and plotted as expression relative to the BM-CCR2+/+ group of each time point (mean ± SEM; n = 7–10 mice per group). *P < 0.05 compared with the BM-CCR2+/+ group. **P < 0.01 compared with the BM-CCR2+/+ group. ***P < 0.001 compared with the BM-CCR2+/+ group.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3198070&req=5

Figure 3: A unique F4/80lo myeloid population accumulates in the SVF of the adipose tissue of BM-CCR2−/− mice. SVCs isolated from BM-CCR2+/+ and BM-CCR2−/− mice were analyzed by flow cytometry. Representative flow cytometry histogram of F4/80-expressing populations in a BM-CCR2+/+ mouse (A) and in a BM-CCR2−/− mouse (B) gated on all live cells. C: Quantification of F4/80lo vs. F4/80hi cell percentages after 6, 12, and 20 weeks of an HFD in the BM-CCR2−/− mice (mean ± SEM; n = 3–5). D–F: RNA was isolated from adipose tissue and used for gene expression analysis by real-time RT-PCR. The mRNA expression of Mpo, Il8rb, Cxcl2, and Cxcl1 was assessed after 6 (D), 12 (E), and 20 (F) weeks of HFD feeding and plotted as expression relative to the BM-CCR2+/+ group of each time point (mean ± SEM; n = 7–10 mice per group). *P < 0.05 compared with the BM-CCR2+/+ group. **P < 0.01 compared with the BM-CCR2+/+ group. ***P < 0.001 compared with the BM-CCR2+/+ group.
Mentions: Based on our observation that there were no changes in immune infiltration in adipose tissue after 6 and 12 weeks of HFD feeding despite the dramatic reduction in circulating inflammatory cells, we sought to further characterize the macrophages in adipose tissue by flow cytometry. To this end, we performed careful evaluation of the F4/80+ cells within adipose tissue. Based on our gating strategy, the BM-CCR2+/+ mice contained the expected F4/80− and F4/80hi populations (Fig. 3A). Interestingly, the BM-CCR2−/− mice accumulated two discrete myeloid populations in their adipose tissue: F4/80lo and F4/80hi (Fig. 3B). The discrete F4/80lo population was observed in the SVF of the BM-CCR2−/− at the 6-week (Fig. 3B and C) and 12-week (Fig. 3C and Supplementary Fig. 8B) time points but was no longer detected after 20 weeks of HFD feeding (Fig. 3C and Supplementary Fig. 8D).

Bottom Line: Adipose tissue myeloid populations, degree of inflammation, glucose tolerance, and insulin sensitivity were assessed.Gene expression and histological analysis of the CD11b(lo)F4/80(lo) cells indicated that they are a unique undifferentiated monocytic inflammatory population.The discovery of this novel adipose tissue monocytic cell population provides advances toward understanding the pleiotropic role of CCR2 in monocyte/macrophage accumulation and regulation of adipose tissue inflammation.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee, USA.

ABSTRACT

Objective: Mice with CCR2 deficiency are protected from insulin resistance but only after long periods of high-fat diet (HFD) feeding, despite the virtual absence of circulating inflammatory monocytes. We performed a time course study in mice with hematopoietic and global CCR2 deficiency to determine adipose tissue-specific mechanisms for the delayed impact of CCR2 deficiency on insulin resistance.

Research design and methods: Mice with global or hematopoietic CCR2 deficiency (CCR2(-/-) and BM-CCR2(-/-), respectively) and wild-type controls (CCR2(+/+) and BM-CCR2(+/+), respectively) were placed on an HFD for 6, 12, and 20 weeks. Adipose tissue myeloid populations, degree of inflammation, glucose tolerance, and insulin sensitivity were assessed.

Results: Flow cytometry analysis showed that two different populations of F4/80(+) myeloid cells (CD11b(lo)F4/80(lo) and CD11b(hi)F4/80(hi)) accumulated in the adipose tissue of CCR2(-/-) and BM-CCR2(-/-) mice after 6 and 12 weeks of HFD feeding, whereas only the CD11b(hi)F4/80(hi) population was detected in the CCR2(+/+) and BM-CCR2(+/+) controls. After 20 weeks of HFD feeding, the CD11b(lo)F4/80(lo) cells were no longer present in the adipose tissue of CCR2(-/-) mice, and only then were improvements in adipose tissue inflammation detected. Gene expression and histological analysis of the CD11b(lo)F4/80(lo) cells indicated that they are a unique undifferentiated monocytic inflammatory population. The CD11b(lo)F4/80(lo) cells are transiently found in wild-type mice, but CCR2 deficiency leads to the aberrant accumulation of these cells in adipose tissue.

Conclusions: The discovery of this novel adipose tissue monocytic cell population provides advances toward understanding the pleiotropic role of CCR2 in monocyte/macrophage accumulation and regulation of adipose tissue inflammation.

Show MeSH
Related in: MedlinePlus