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Potential role of regulatory T cells in reversing obesity-linked insulin resistance and diabetic nephropathy.

Eller K, Kirsch A, Wolf AM, Sopper S, Tagwerker A, Stanzl U, Wolf D, Patsch W, Rosenkranz AR, Eller P - Diabetes (2011)

Bottom Line: Obese patients with insulin resistance displayed significantly decreased natural Tregs but an increase in adaptive Tregs in their visceral adipose tissue as compared with lean control subjects.Conversely, adoptive transfer of CD4(+)FoxP3(+) Tregs significantly improved insulin sensitivity and diabetic nephropathy.Accordingly, there was increased mRNA expression of FoxP3 as well as less abundant proinflammatory CD8(+)CD69(+) T cells in visceral adipose tissue and kidneys of Treg-treated animals.

View Article: PubMed Central - PubMed

Affiliation: Clinical Division of Nephrology, Department of Internal Medicine, Medical University Graz, Graz, Austria. kathrin.eller@medunigraz.at

ABSTRACT

Objective: To assess the potential role of FoxP3-expressing regulatory T cells (Tregs) in reversing obesity-linked insulin resistance and diabetic nephropathy in rodent models and humans.

Research design and methods: To characterize the role of Tregs in insulin resistance, human visceral adipose tissue was first evaluated for Treg infiltration and second, the db/db mouse model was evaluated.

Results: Obese patients with insulin resistance displayed significantly decreased natural Tregs but an increase in adaptive Tregs in their visceral adipose tissue as compared with lean control subjects. To further evaluate the pathogenic role of Tregs in insulin resistance, the db/db mouse model was used. Treg depletion using an anti-CD25 monoclonal antibody enhanced insulin resistance as shown by increased fasting blood glucose levels as well as an impaired insulin sensitivity. Moreover, Treg-depleted db/db mice developed increased signs of diabetic nephropathy, such as albuminuria and glomerular hyperfiltration. This was paralleled by a proinflammatory milieu in both murine visceral adipose tissue and the kidney. Conversely, adoptive transfer of CD4(+)FoxP3(+) Tregs significantly improved insulin sensitivity and diabetic nephropathy. Accordingly, there was increased mRNA expression of FoxP3 as well as less abundant proinflammatory CD8(+)CD69(+) T cells in visceral adipose tissue and kidneys of Treg-treated animals.

Conclusions: Data suggest a potential therapeutic value of Tregs to improve insulin resistance and end organ damage in type 2 diabetes by limiting the proinflammatory milieu.

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Related in: MedlinePlus

Treg treatment induces a shift toward an anti-inflammatory milieu in VAT. Db/db mice were uninephrectomized at the age of 6 weeks and followed for 56 days. One group intravenously received FACS-sorted CD4+FoxP3+ Tregs every 14 days (gray bar), whereas the control group was injected with CD4+FoxP3− control T cells (black bar). A: The VAT cell diameter was determined by morphological evaluation (n = 4 per group). B: The cytokine response in VAT was quantified by real-time PCR (n = 8 per group). The fold increase to the mean expression of controls is provided. C: The percentage of CD4+CD69+ and CD8+CD69+ T cells was evaluated in VAT and SAT by flow cytometry (n = 4 per group). Pooled or representative data of two independent experiments are shown. *P < 0.05. D: Representative dot plots from gated CD8+ T cells and from CD8/CD69 double staining in VAT. FSC-H, forward scatter height.
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Figure 6: Treg treatment induces a shift toward an anti-inflammatory milieu in VAT. Db/db mice were uninephrectomized at the age of 6 weeks and followed for 56 days. One group intravenously received FACS-sorted CD4+FoxP3+ Tregs every 14 days (gray bar), whereas the control group was injected with CD4+FoxP3− control T cells (black bar). A: The VAT cell diameter was determined by morphological evaluation (n = 4 per group). B: The cytokine response in VAT was quantified by real-time PCR (n = 8 per group). The fold increase to the mean expression of controls is provided. C: The percentage of CD4+CD69+ and CD8+CD69+ T cells was evaluated in VAT and SAT by flow cytometry (n = 4 per group). Pooled or representative data of two independent experiments are shown. *P < 0.05. D: Representative dot plots from gated CD8+ T cells and from CD8/CD69 double staining in VAT. FSC-H, forward scatter height.

Mentions: Db/db mice underwent uninephrectomy at the age of 6 weeks. On days 4, 18, 32, and 46 after uninephrectomy, CD4+FoxP3+GFP+ (Tregs) or CD4+FoxP3−GFP− (control) T cells isolated from healthy donor animals were adoptively transferred into db/db mice. No difference in the body weight was observed between the two groups (Fig. 5A). The blood glucose levels were significantly decreased only in the Treg-treated mice on day 28, whereas on the other evaluated time points, no difference between the groups was detectable (Fig. 5B). Moreover, significantly improved insulin sensitivity was observed in db/db mice treated with Tregs compared with db/db mice injected with control T cells (Fig. 5C). A trend toward an improved HOMA-IR in Treg-treated obese animals was detected, but no statistical significance was reached (Fig. 5D). In addition, Treg-treated db/db mice displayed a significantly decreased mVAT cell diameter as compared with controls (Fig. 6A), whereas we could not detect any difference in the mSAT cell diameters (data not shown). Treg transfer increased the expression of the Treg marker FoxP3 and the Th1 cytokine IFN-γ in mVAT, whereas IL-6, TNF-α, Gata-3, and IL-10 mRNA were not differentially regulated (Fig. 6B). It is interesting that the percentage of proinflammatory mVAT-infiltrating CD8+CD69+ effector T cells was significantly decreased in Treg-treated db/db mice (Fig. 6C and D), whereas no difference of these cells could be detected in mSAT (Fig. 6C). Of note, no difference in the mVAT and mSAT infiltration of CD4+CD69+ T cells was observed (Fig. 6C).


Potential role of regulatory T cells in reversing obesity-linked insulin resistance and diabetic nephropathy.

Eller K, Kirsch A, Wolf AM, Sopper S, Tagwerker A, Stanzl U, Wolf D, Patsch W, Rosenkranz AR, Eller P - Diabetes (2011)

Treg treatment induces a shift toward an anti-inflammatory milieu in VAT. Db/db mice were uninephrectomized at the age of 6 weeks and followed for 56 days. One group intravenously received FACS-sorted CD4+FoxP3+ Tregs every 14 days (gray bar), whereas the control group was injected with CD4+FoxP3− control T cells (black bar). A: The VAT cell diameter was determined by morphological evaluation (n = 4 per group). B: The cytokine response in VAT was quantified by real-time PCR (n = 8 per group). The fold increase to the mean expression of controls is provided. C: The percentage of CD4+CD69+ and CD8+CD69+ T cells was evaluated in VAT and SAT by flow cytometry (n = 4 per group). Pooled or representative data of two independent experiments are shown. *P < 0.05. D: Representative dot plots from gated CD8+ T cells and from CD8/CD69 double staining in VAT. FSC-H, forward scatter height.
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Figure 6: Treg treatment induces a shift toward an anti-inflammatory milieu in VAT. Db/db mice were uninephrectomized at the age of 6 weeks and followed for 56 days. One group intravenously received FACS-sorted CD4+FoxP3+ Tregs every 14 days (gray bar), whereas the control group was injected with CD4+FoxP3− control T cells (black bar). A: The VAT cell diameter was determined by morphological evaluation (n = 4 per group). B: The cytokine response in VAT was quantified by real-time PCR (n = 8 per group). The fold increase to the mean expression of controls is provided. C: The percentage of CD4+CD69+ and CD8+CD69+ T cells was evaluated in VAT and SAT by flow cytometry (n = 4 per group). Pooled or representative data of two independent experiments are shown. *P < 0.05. D: Representative dot plots from gated CD8+ T cells and from CD8/CD69 double staining in VAT. FSC-H, forward scatter height.
Mentions: Db/db mice underwent uninephrectomy at the age of 6 weeks. On days 4, 18, 32, and 46 after uninephrectomy, CD4+FoxP3+GFP+ (Tregs) or CD4+FoxP3−GFP− (control) T cells isolated from healthy donor animals were adoptively transferred into db/db mice. No difference in the body weight was observed between the two groups (Fig. 5A). The blood glucose levels were significantly decreased only in the Treg-treated mice on day 28, whereas on the other evaluated time points, no difference between the groups was detectable (Fig. 5B). Moreover, significantly improved insulin sensitivity was observed in db/db mice treated with Tregs compared with db/db mice injected with control T cells (Fig. 5C). A trend toward an improved HOMA-IR in Treg-treated obese animals was detected, but no statistical significance was reached (Fig. 5D). In addition, Treg-treated db/db mice displayed a significantly decreased mVAT cell diameter as compared with controls (Fig. 6A), whereas we could not detect any difference in the mSAT cell diameters (data not shown). Treg transfer increased the expression of the Treg marker FoxP3 and the Th1 cytokine IFN-γ in mVAT, whereas IL-6, TNF-α, Gata-3, and IL-10 mRNA were not differentially regulated (Fig. 6B). It is interesting that the percentage of proinflammatory mVAT-infiltrating CD8+CD69+ effector T cells was significantly decreased in Treg-treated db/db mice (Fig. 6C and D), whereas no difference of these cells could be detected in mSAT (Fig. 6C). Of note, no difference in the mVAT and mSAT infiltration of CD4+CD69+ T cells was observed (Fig. 6C).

Bottom Line: Obese patients with insulin resistance displayed significantly decreased natural Tregs but an increase in adaptive Tregs in their visceral adipose tissue as compared with lean control subjects.Conversely, adoptive transfer of CD4(+)FoxP3(+) Tregs significantly improved insulin sensitivity and diabetic nephropathy.Accordingly, there was increased mRNA expression of FoxP3 as well as less abundant proinflammatory CD8(+)CD69(+) T cells in visceral adipose tissue and kidneys of Treg-treated animals.

View Article: PubMed Central - PubMed

Affiliation: Clinical Division of Nephrology, Department of Internal Medicine, Medical University Graz, Graz, Austria. kathrin.eller@medunigraz.at

ABSTRACT

Objective: To assess the potential role of FoxP3-expressing regulatory T cells (Tregs) in reversing obesity-linked insulin resistance and diabetic nephropathy in rodent models and humans.

Research design and methods: To characterize the role of Tregs in insulin resistance, human visceral adipose tissue was first evaluated for Treg infiltration and second, the db/db mouse model was evaluated.

Results: Obese patients with insulin resistance displayed significantly decreased natural Tregs but an increase in adaptive Tregs in their visceral adipose tissue as compared with lean control subjects. To further evaluate the pathogenic role of Tregs in insulin resistance, the db/db mouse model was used. Treg depletion using an anti-CD25 monoclonal antibody enhanced insulin resistance as shown by increased fasting blood glucose levels as well as an impaired insulin sensitivity. Moreover, Treg-depleted db/db mice developed increased signs of diabetic nephropathy, such as albuminuria and glomerular hyperfiltration. This was paralleled by a proinflammatory milieu in both murine visceral adipose tissue and the kidney. Conversely, adoptive transfer of CD4(+)FoxP3(+) Tregs significantly improved insulin sensitivity and diabetic nephropathy. Accordingly, there was increased mRNA expression of FoxP3 as well as less abundant proinflammatory CD8(+)CD69(+) T cells in visceral adipose tissue and kidneys of Treg-treated animals.

Conclusions: Data suggest a potential therapeutic value of Tregs to improve insulin resistance and end organ damage in type 2 diabetes by limiting the proinflammatory milieu.

Show MeSH
Related in: MedlinePlus