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A Rac1 inhibitory peptide suppresses antibody production and paw swelling in the murine collagen-induced arthritis model of rheumatoid arthritis.

Abreu JR, Dontje W, Krausz S, de Launay D, van Hennik PB, van Stalborch AM, Ten Klooster JP, Sanders ME, Reedquist KA, Vervoordeldonk MJ, Hordijk PL, Tak PP - Arthritis Res. Ther. (2010)

Bottom Line: Results were analyzed using Mann-Whitney U and unpaired Student t tests.The data suggest that targeting of Rac1 with the Rac1 carboxy-terminal inhibitory peptide may suppress T-cell activation and autoantibody production in autoimmune disease.Whether this could translate into clinically meaningful improvement remains to be shown.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands. j.r.abreu@amc.uva.nl

ABSTRACT

Introduction: The Rho family GTPase Rac1 regulates cytoskeletal rearrangements crucial for the recruitment, extravasation and activation of leukocytes at sites of inflammation. Rac1 signaling also promotes the activation and survival of lymphocytes and osteoclasts. Therefore, we assessed the ability of a cell-permeable Rac1 carboxy-terminal inhibitory peptide to modulate disease in mice with collagen-induced arthritis (CIA).

Methods: CIA was induced in DBA/1 mice, and in either early or chronic disease, mice were treated three times per week by intraperitoneal injection with control peptide or Rac1 inhibitory peptide. Effects on disease progression were assessed by measurement of paw swelling. Inflammation and joint destruction were examined by histology and radiology. Serum levels of anti-collagen type II antibodies were measured by enzyme-linked immunosorbent assay. T-cell phenotypes and activation were assessed by fluorescence-activated cell sorting analysis. Results were analyzed using Mann-Whitney U and unpaired Student t tests.

Results: Treatment of mice with Rac1 inhibitory peptide resulted in a decrease in paw swelling in early disease and to a lesser extent in more chronic arthritis. Of interest, while joint destruction was unaffected by Rac1 inhibitory peptide, anti-collagen type II antibody production was significantly diminished in treated mice, in both early and chronic arthritis. Ex vivo, Rac1 inhibitory peptide suppressed T-cell receptor/CD28-dependent production of tumor necrosis factor alpha, interferon gamma and interleukin-17 by T cells from collagen-primed mice, and reduced induction of ICOS and CD154, T-cell costimulatory proteins important for B-cell help.

Conclusions: The data suggest that targeting of Rac1 with the Rac1 carboxy-terminal inhibitory peptide may suppress T-cell activation and autoantibody production in autoimmune disease. Whether this could translate into clinically meaningful improvement remains to be shown.

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Effect of Rac1 carboxy-terminal peptide treatment of mice with chronic arthritis. (a) Delta hind paw ankle joint swelling of mice that started treatment at day 29 with 4 mg of Ctrl or Rac1 peptide (three times weekly). Values are representative of two independent experiments (n = 16 per group). (b) Area under the curve (AUC) calculated as in Figure 2b. Paraffin-embedded sections of the hind paws were stained with hematoxylin and eosin and analyzed for (c) synovial inflammation and (d) cartilage destruction. (e) X-rays were analyzed for bone damage (n = 16 per group). (f) Sera from mice that started treatment at day 29 (n = 7) with Ctrl (white bars) or Rac1 (black bars) peptide were collected, and the levels of specific anti-collagen IgG were detected. IgG levels in the sera of Ctrl-treated mice were set to 100%, and the levels obtained in the sera of Rac1 peptide-treated mice were then calculated relative to Ctrl. Represented values were calculated within linear regions of the serum dilution curve. All values are expressed as mean ± standard error of the mean. *P ≤ 0.05. Ctrl, control.
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Figure 4: Effect of Rac1 carboxy-terminal peptide treatment of mice with chronic arthritis. (a) Delta hind paw ankle joint swelling of mice that started treatment at day 29 with 4 mg of Ctrl or Rac1 peptide (three times weekly). Values are representative of two independent experiments (n = 16 per group). (b) Area under the curve (AUC) calculated as in Figure 2b. Paraffin-embedded sections of the hind paws were stained with hematoxylin and eosin and analyzed for (c) synovial inflammation and (d) cartilage destruction. (e) X-rays were analyzed for bone damage (n = 16 per group). (f) Sera from mice that started treatment at day 29 (n = 7) with Ctrl (white bars) or Rac1 (black bars) peptide were collected, and the levels of specific anti-collagen IgG were detected. IgG levels in the sera of Ctrl-treated mice were set to 100%, and the levels obtained in the sera of Rac1 peptide-treated mice were then calculated relative to Ctrl. Represented values were calculated within linear regions of the serum dilution curve. All values are expressed as mean ± standard error of the mean. *P ≤ 0.05. Ctrl, control.

Mentions: We next investigated the effect of Rac1 peptide treatment on mice with chronic arthritis. For this, we performed an independent CIA experiment wherein 29 days after the initial immunization, mice having clinical signs of arthritis were randomly assigned to one of two groups. Mice within groups were treated with 4 mg of Ctrl or 4 mg of Rac1 peptide three times weekly until sacrifice. Administration of Rac1 peptide had no influence on clinical disease severity (data not shown). However, we observed a clear trend toward reduced paw swelling in mice treated with Rac1 peptide (Figure 4a, b) in two independent experiments, although the differences did not reach statistical significance (experiment 1: 49% reduction, P = 0.528; experiment 2: 22% reduction, P = 0.193) (Figure 4b).


A Rac1 inhibitory peptide suppresses antibody production and paw swelling in the murine collagen-induced arthritis model of rheumatoid arthritis.

Abreu JR, Dontje W, Krausz S, de Launay D, van Hennik PB, van Stalborch AM, Ten Klooster JP, Sanders ME, Reedquist KA, Vervoordeldonk MJ, Hordijk PL, Tak PP - Arthritis Res. Ther. (2010)

Effect of Rac1 carboxy-terminal peptide treatment of mice with chronic arthritis. (a) Delta hind paw ankle joint swelling of mice that started treatment at day 29 with 4 mg of Ctrl or Rac1 peptide (three times weekly). Values are representative of two independent experiments (n = 16 per group). (b) Area under the curve (AUC) calculated as in Figure 2b. Paraffin-embedded sections of the hind paws were stained with hematoxylin and eosin and analyzed for (c) synovial inflammation and (d) cartilage destruction. (e) X-rays were analyzed for bone damage (n = 16 per group). (f) Sera from mice that started treatment at day 29 (n = 7) with Ctrl (white bars) or Rac1 (black bars) peptide were collected, and the levels of specific anti-collagen IgG were detected. IgG levels in the sera of Ctrl-treated mice were set to 100%, and the levels obtained in the sera of Rac1 peptide-treated mice were then calculated relative to Ctrl. Represented values were calculated within linear regions of the serum dilution curve. All values are expressed as mean ± standard error of the mean. *P ≤ 0.05. Ctrl, control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2875627&req=5

Figure 4: Effect of Rac1 carboxy-terminal peptide treatment of mice with chronic arthritis. (a) Delta hind paw ankle joint swelling of mice that started treatment at day 29 with 4 mg of Ctrl or Rac1 peptide (three times weekly). Values are representative of two independent experiments (n = 16 per group). (b) Area under the curve (AUC) calculated as in Figure 2b. Paraffin-embedded sections of the hind paws were stained with hematoxylin and eosin and analyzed for (c) synovial inflammation and (d) cartilage destruction. (e) X-rays were analyzed for bone damage (n = 16 per group). (f) Sera from mice that started treatment at day 29 (n = 7) with Ctrl (white bars) or Rac1 (black bars) peptide were collected, and the levels of specific anti-collagen IgG were detected. IgG levels in the sera of Ctrl-treated mice were set to 100%, and the levels obtained in the sera of Rac1 peptide-treated mice were then calculated relative to Ctrl. Represented values were calculated within linear regions of the serum dilution curve. All values are expressed as mean ± standard error of the mean. *P ≤ 0.05. Ctrl, control.
Mentions: We next investigated the effect of Rac1 peptide treatment on mice with chronic arthritis. For this, we performed an independent CIA experiment wherein 29 days after the initial immunization, mice having clinical signs of arthritis were randomly assigned to one of two groups. Mice within groups were treated with 4 mg of Ctrl or 4 mg of Rac1 peptide three times weekly until sacrifice. Administration of Rac1 peptide had no influence on clinical disease severity (data not shown). However, we observed a clear trend toward reduced paw swelling in mice treated with Rac1 peptide (Figure 4a, b) in two independent experiments, although the differences did not reach statistical significance (experiment 1: 49% reduction, P = 0.528; experiment 2: 22% reduction, P = 0.193) (Figure 4b).

Bottom Line: Results were analyzed using Mann-Whitney U and unpaired Student t tests.The data suggest that targeting of Rac1 with the Rac1 carboxy-terminal inhibitory peptide may suppress T-cell activation and autoantibody production in autoimmune disease.Whether this could translate into clinically meaningful improvement remains to be shown.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands. j.r.abreu@amc.uva.nl

ABSTRACT

Introduction: The Rho family GTPase Rac1 regulates cytoskeletal rearrangements crucial for the recruitment, extravasation and activation of leukocytes at sites of inflammation. Rac1 signaling also promotes the activation and survival of lymphocytes and osteoclasts. Therefore, we assessed the ability of a cell-permeable Rac1 carboxy-terminal inhibitory peptide to modulate disease in mice with collagen-induced arthritis (CIA).

Methods: CIA was induced in DBA/1 mice, and in either early or chronic disease, mice were treated three times per week by intraperitoneal injection with control peptide or Rac1 inhibitory peptide. Effects on disease progression were assessed by measurement of paw swelling. Inflammation and joint destruction were examined by histology and radiology. Serum levels of anti-collagen type II antibodies were measured by enzyme-linked immunosorbent assay. T-cell phenotypes and activation were assessed by fluorescence-activated cell sorting analysis. Results were analyzed using Mann-Whitney U and unpaired Student t tests.

Results: Treatment of mice with Rac1 inhibitory peptide resulted in a decrease in paw swelling in early disease and to a lesser extent in more chronic arthritis. Of interest, while joint destruction was unaffected by Rac1 inhibitory peptide, anti-collagen type II antibody production was significantly diminished in treated mice, in both early and chronic arthritis. Ex vivo, Rac1 inhibitory peptide suppressed T-cell receptor/CD28-dependent production of tumor necrosis factor alpha, interferon gamma and interleukin-17 by T cells from collagen-primed mice, and reduced induction of ICOS and CD154, T-cell costimulatory proteins important for B-cell help.

Conclusions: The data suggest that targeting of Rac1 with the Rac1 carboxy-terminal inhibitory peptide may suppress T-cell activation and autoantibody production in autoimmune disease. Whether this could translate into clinically meaningful improvement remains to be shown.

Show MeSH
Related in: MedlinePlus