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Genetic deficiency of Itgb2 or ItgaL prevents autoimmune diabetes through distinctly different mechanisms in NOD/LtJ mice.

Glawe JD, Patrick DR, Huang M, Sharp CD, Barlow SC, Kevil CG - Diabetes (2009)

Bottom Line: However, ItgaL deficiency did not alter NOD T-cell adhesion to or transmigration across islet endothelial cells.Adoptive transfer of ItgaL-deficient splenocytes into NOD/Rag-1 mice did not result in development of diabetes, suggesting a role for ItgaL in NOD/LtJ T-cell activation.Together, these data demonstrate that genetic deficiency of Itgb2 or ItgaL confers protection against autoimmune diabetes through distinctly different mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Louisiana State University Health Sciences Center Shreveport, Shreveport, Louisiana, USA.

ABSTRACT

Objective: Insulitis is an important pathological feature of autoimmune diabetes; however, mechanisms governing the recruitment of diabetogenic T-cells into pancreatic islets are poorly understood. Here, we determined the importance of leukocyte integrins beta(2)(Itgb2) and alphaL (ItgaL) in developing insulitis and frank diabetes.

Research design and methods: Gene-targeted mutations of either Itgb2 or ItgaL were established on the NOD/LtJ mouse strain. Experiments were performed to measure insulitis and diabetes development. Studies were also performed measuring mutant T-cell adhesion to islet microvascular endothelial cells under hydrodynamic flow conditions. T-cell adhesion molecule profiles and adoptive transfer studies were also performed.

Results: Genetic deficiency of either Itgb2 or ItgaL completely prevented the development of hyperglycemia and frank diabetes in NOD mice. Loss of Itgb2 or ItgaL prevented insulitis with Itgb2 deficiency conferring complete protection. In vitro hydrodynamic flow adhesion studies also showed that loss of Itgb2 completely abrogated T-cell adhesion. However, ItgaL deficiency did not alter NOD T-cell adhesion to or transmigration across islet endothelial cells. Adoptive transfer of ItgaL-deficient splenocytes into NOD/Rag-1 mice did not result in development of diabetes, suggesting a role for ItgaL in NOD/LtJ T-cell activation.

Conclusions: Together, these data demonstrate that genetic deficiency of Itgb2 or ItgaL confers protection against autoimmune diabetes through distinctly different mechanisms.

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Loss of Itgb2 or ItgaL expression alters NOD/LtJ T-cell adhesion molecule expression. Whole splenocytes were isolated from wild-type pre-diabetic (12 weeks old), wild-type diabetic (18 weeks old), Itgb2−/−  (18 weeks old), and ItgaL−/−  (18 weeks old) NOD/LtJ mice and stained for CD3 and individual adhesion molecules to determine the amount of surface adhesion molecule expression. A: The mean fluorescence intensity for CD11a expression. B: The mean fluorescence intensity for CD18 expression. C: The mean fluorescence intensity for CD49d expression. D: The mean fluorescence intensity for CD29 expression. E: The mean fluorescence intensity for CD62L expression. F: The mean fluorescence intensity for LPAM-1 expression. *P < 0.01 vs. wild-type diabetic mice; # P < 0.01 Itgb2  vs. ItgaL  mice, n = 6–7 animals per genotype.
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Figure 3: Loss of Itgb2 or ItgaL expression alters NOD/LtJ T-cell adhesion molecule expression. Whole splenocytes were isolated from wild-type pre-diabetic (12 weeks old), wild-type diabetic (18 weeks old), Itgb2−/− (18 weeks old), and ItgaL−/− (18 weeks old) NOD/LtJ mice and stained for CD3 and individual adhesion molecules to determine the amount of surface adhesion molecule expression. A: The mean fluorescence intensity for CD11a expression. B: The mean fluorescence intensity for CD18 expression. C: The mean fluorescence intensity for CD49d expression. D: The mean fluorescence intensity for CD29 expression. E: The mean fluorescence intensity for CD62L expression. F: The mean fluorescence intensity for LPAM-1 expression. *P < 0.01 vs. wild-type diabetic mice; # P < 0.01 Itgb2 vs. ItgaL mice, n = 6–7 animals per genotype.

Mentions: Figure 3 reports the mean fluorescence intensity of adhesion molecule expression on CD3 T-cells from wild-type and mutant NOD/LtJ mice.Figure 3A shows that genetic deficiency of either ItgaL or Itgb2 significantly decreases CD11a surface expression. Similarly,Fig. 3B shows that genetic deficiency of either molecule also significantly decreases CD18 surface expression. However, robust CD18 surface expression is observed on ItgaL CD3 T-cells compared with absent expression on Itgb2 CD3 cells. Again, these data indicate that other β2integrins may be expressed in lieu of ItgaL deficiency. Interestingly, Itgb2 deficiency enhances CD29 surface expression (Fig. 3D). CD3 T-cell surface expression of CD62L is similarly decreased in either ItgaL or Itgb2 mice (Fig. 3E). Lastly, surface expression of LPAM-1 was unchanged among wild-type and mutant NOD/LtJ CD3 T-cells (Fig. 3F).


Genetic deficiency of Itgb2 or ItgaL prevents autoimmune diabetes through distinctly different mechanisms in NOD/LtJ mice.

Glawe JD, Patrick DR, Huang M, Sharp CD, Barlow SC, Kevil CG - Diabetes (2009)

Loss of Itgb2 or ItgaL expression alters NOD/LtJ T-cell adhesion molecule expression. Whole splenocytes were isolated from wild-type pre-diabetic (12 weeks old), wild-type diabetic (18 weeks old), Itgb2−/−  (18 weeks old), and ItgaL−/−  (18 weeks old) NOD/LtJ mice and stained for CD3 and individual adhesion molecules to determine the amount of surface adhesion molecule expression. A: The mean fluorescence intensity for CD11a expression. B: The mean fluorescence intensity for CD18 expression. C: The mean fluorescence intensity for CD49d expression. D: The mean fluorescence intensity for CD29 expression. E: The mean fluorescence intensity for CD62L expression. F: The mean fluorescence intensity for LPAM-1 expression. *P < 0.01 vs. wild-type diabetic mice; # P < 0.01 Itgb2  vs. ItgaL  mice, n = 6–7 animals per genotype.
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Figure 3: Loss of Itgb2 or ItgaL expression alters NOD/LtJ T-cell adhesion molecule expression. Whole splenocytes were isolated from wild-type pre-diabetic (12 weeks old), wild-type diabetic (18 weeks old), Itgb2−/− (18 weeks old), and ItgaL−/− (18 weeks old) NOD/LtJ mice and stained for CD3 and individual adhesion molecules to determine the amount of surface adhesion molecule expression. A: The mean fluorescence intensity for CD11a expression. B: The mean fluorescence intensity for CD18 expression. C: The mean fluorescence intensity for CD49d expression. D: The mean fluorescence intensity for CD29 expression. E: The mean fluorescence intensity for CD62L expression. F: The mean fluorescence intensity for LPAM-1 expression. *P < 0.01 vs. wild-type diabetic mice; # P < 0.01 Itgb2 vs. ItgaL mice, n = 6–7 animals per genotype.
Mentions: Figure 3 reports the mean fluorescence intensity of adhesion molecule expression on CD3 T-cells from wild-type and mutant NOD/LtJ mice.Figure 3A shows that genetic deficiency of either ItgaL or Itgb2 significantly decreases CD11a surface expression. Similarly,Fig. 3B shows that genetic deficiency of either molecule also significantly decreases CD18 surface expression. However, robust CD18 surface expression is observed on ItgaL CD3 T-cells compared with absent expression on Itgb2 CD3 cells. Again, these data indicate that other β2integrins may be expressed in lieu of ItgaL deficiency. Interestingly, Itgb2 deficiency enhances CD29 surface expression (Fig. 3D). CD3 T-cell surface expression of CD62L is similarly decreased in either ItgaL or Itgb2 mice (Fig. 3E). Lastly, surface expression of LPAM-1 was unchanged among wild-type and mutant NOD/LtJ CD3 T-cells (Fig. 3F).

Bottom Line: However, ItgaL deficiency did not alter NOD T-cell adhesion to or transmigration across islet endothelial cells.Adoptive transfer of ItgaL-deficient splenocytes into NOD/Rag-1 mice did not result in development of diabetes, suggesting a role for ItgaL in NOD/LtJ T-cell activation.Together, these data demonstrate that genetic deficiency of Itgb2 or ItgaL confers protection against autoimmune diabetes through distinctly different mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Louisiana State University Health Sciences Center Shreveport, Shreveport, Louisiana, USA.

ABSTRACT

Objective: Insulitis is an important pathological feature of autoimmune diabetes; however, mechanisms governing the recruitment of diabetogenic T-cells into pancreatic islets are poorly understood. Here, we determined the importance of leukocyte integrins beta(2)(Itgb2) and alphaL (ItgaL) in developing insulitis and frank diabetes.

Research design and methods: Gene-targeted mutations of either Itgb2 or ItgaL were established on the NOD/LtJ mouse strain. Experiments were performed to measure insulitis and diabetes development. Studies were also performed measuring mutant T-cell adhesion to islet microvascular endothelial cells under hydrodynamic flow conditions. T-cell adhesion molecule profiles and adoptive transfer studies were also performed.

Results: Genetic deficiency of either Itgb2 or ItgaL completely prevented the development of hyperglycemia and frank diabetes in NOD mice. Loss of Itgb2 or ItgaL prevented insulitis with Itgb2 deficiency conferring complete protection. In vitro hydrodynamic flow adhesion studies also showed that loss of Itgb2 completely abrogated T-cell adhesion. However, ItgaL deficiency did not alter NOD T-cell adhesion to or transmigration across islet endothelial cells. Adoptive transfer of ItgaL-deficient splenocytes into NOD/Rag-1 mice did not result in development of diabetes, suggesting a role for ItgaL in NOD/LtJ T-cell activation.

Conclusions: Together, these data demonstrate that genetic deficiency of Itgb2 or ItgaL confers protection against autoimmune diabetes through distinctly different mechanisms.

Show MeSH
Related in: MedlinePlus