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Reduced incidence and severity of antigen-induced autoimmune diseases in mice lacking interferon regulatory factor-1.

Tada Y, Ho A, Matsuyama T, Mak TW - J. Exp. Med. (1997)

Bottom Line: Interferon regulatory factor-1 (IRF-1) is a transcription factor that regulates interferon-induced genes and type I interferons.The incidence and severity of CIA were significantly decreased in IRF-1-/- mice compared with IRF-l +/- mice, as was the production of interferon (IFN)-gamma in lymph node cells.Expression of iNOS was also detected in inflamed spinal cords.

View Article: PubMed Central - PubMed

Affiliation: Amgen Institute, Department of Medical Biophysics, University of Toronto, Ontario, Canada.

ABSTRACT
Interferon regulatory factor-1 (IRF-1) is a transcription factor that regulates interferon-induced genes and type I interferons. Recently, studies of IRF-l-deficient mice have revealed that IRF-I regulates the induction of molecules that play important roles in inflammation, such as inducible nitric oxide synthase (iNOS) and interleukin-l beta-converting enzyme (ICE). To study the role of IRF-1 in autoimmunity, we investigated type II collagen-induced arthritis (CIA), and experimental allergic encephalomyelitis (EAE), in mice lacking IRF-1. The incidence and severity of CIA were significantly decreased in IRF-1-/- mice compared with IRF-l +/- mice, as was the production of interferon (IFN)-gamma in lymph node cells. Both IRF-l+/- and IRF-1-/- mice exhibited mild and transient disease after adoptive transfer of a type II collagen (CII)-specific T cell line together with sera from arthritic mice, but the IRF-1-/- mice were less severely affected than the IRF-1+/- mice. In addition, the incidence of EAE in IRF-1-/- mice was decreased as compared with IRF-1 +/- mice. Reverse transcription polymerase chain reaction showed that IRF-1 mRNA was constitutively expressed in the spinal cords of IRF-1+/- mice, and was upregulated in mice with clinical EAE. Expression of iNOS was also detected in inflamed spinal cords. These results suggest that IRF-I plays a key role in promoting inflammation and autoimmunity in CIA and EAE animal models.

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RT-PCR study of IRF-1 (A) and iNOS (C) mRNA expression in spinal cords from IRF-1+/− (lanes 2–5) and IRF-1−/− (lanes 6 and 7)  PL/J mice with (lanes 4–7) or without (lanes 2 and 3) clinical EAE. Lane 1  is a DNA size marker (φx174 DNA digested with HaeIII). IRF-1 expression was detected in normal spinal cord (lanes 2 and 3) and was increased  in the spinal cords of IRF-1+/− mice with EAE (lanes 4 and 5). No PCR  product was observed in IRF-1−/− samples (lanes 6 and 7). iNOS mRNA  was detected in spinal cords from IRF-1+/− (lanes 4 and 5) and IRF-1−/−  (lane 6) mice with EAE. PCR reactions were run 26 cycles for IRF-1 and  β-actin, and 36 cycles for iNOS. Clinical scores at the time of tissue preparation were the following: lane 4, grade 3.5; lane 5, grade 4; lane 6,  grade 2.5; lane 7, grade 3.5.
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Figure 5: RT-PCR study of IRF-1 (A) and iNOS (C) mRNA expression in spinal cords from IRF-1+/− (lanes 2–5) and IRF-1−/− (lanes 6 and 7) PL/J mice with (lanes 4–7) or without (lanes 2 and 3) clinical EAE. Lane 1 is a DNA size marker (φx174 DNA digested with HaeIII). IRF-1 expression was detected in normal spinal cord (lanes 2 and 3) and was increased in the spinal cords of IRF-1+/− mice with EAE (lanes 4 and 5). No PCR product was observed in IRF-1−/− samples (lanes 6 and 7). iNOS mRNA was detected in spinal cords from IRF-1+/− (lanes 4 and 5) and IRF-1−/− (lane 6) mice with EAE. PCR reactions were run 26 cycles for IRF-1 and β-actin, and 36 cycles for iNOS. Clinical scores at the time of tissue preparation were the following: lane 4, grade 3.5; lane 5, grade 4; lane 6, grade 2.5; lane 7, grade 3.5.

Mentions: IRF-1 plays an important role in the induction of iNOS (9–11), and the resulting NO production in macrophages and other cells is considered to be crucial in promoting inflammation (12). To examine the expression of IRF-1 and iNOS in inflamed tissues, RT-PCR of mRNA from spinal cord (EAE) and joint tissue (CIA) of IRF-1+/− mice with or without clinical disease was carried out. IRF-1 mRNA was detected both in normal spinal cord (Fig. 5, lanes 2 and 3), and in cells from spinal cords with clinical EAE (lane 4, score 3.5; lane 5, score 4). In fact, IFR-1 expression was enhanced in the latter, suggesting an upregulation of IRF-1 mRNA in infiltrating cells and/or resident cells in EAE spinal cord. iNOS mRNA expression was also detected in spinal cords of IRF-1+/− mice with EAE (Fig. 5, lanes 4 and 5). In contrast, IRF-1 expression was not detected in IRF-1−/− mice with clinical EAE (Fig. 5, lane 6, score 2.5; lane 7, score 3.5). However, iNOS mRNA was observed in an IRF-1−/− mouse with moderate EAE (Fig. 5, lane 6), which suggests that iNOS can be induced by an IRF-1-independent pathway. Caution should be exercised in interpreting this result, since >30 cycles of PCR were required to detect expression. In the case of CIA, similar levels of IRF-1 and iNOS mRNA expression were observed in four normal and two arthritic (severity grade 2) IRF-1+/− mice. However, no iNOS signal could be detected in joints from the three arthritic IRF-1−/− mice (two grade 1 and one grade 2).


Reduced incidence and severity of antigen-induced autoimmune diseases in mice lacking interferon regulatory factor-1.

Tada Y, Ho A, Matsuyama T, Mak TW - J. Exp. Med. (1997)

RT-PCR study of IRF-1 (A) and iNOS (C) mRNA expression in spinal cords from IRF-1+/− (lanes 2–5) and IRF-1−/− (lanes 6 and 7)  PL/J mice with (lanes 4–7) or without (lanes 2 and 3) clinical EAE. Lane 1  is a DNA size marker (φx174 DNA digested with HaeIII). IRF-1 expression was detected in normal spinal cord (lanes 2 and 3) and was increased  in the spinal cords of IRF-1+/− mice with EAE (lanes 4 and 5). No PCR  product was observed in IRF-1−/− samples (lanes 6 and 7). iNOS mRNA  was detected in spinal cords from IRF-1+/− (lanes 4 and 5) and IRF-1−/−  (lane 6) mice with EAE. PCR reactions were run 26 cycles for IRF-1 and  β-actin, and 36 cycles for iNOS. Clinical scores at the time of tissue preparation were the following: lane 4, grade 3.5; lane 5, grade 4; lane 6,  grade 2.5; lane 7, grade 3.5.
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Figure 5: RT-PCR study of IRF-1 (A) and iNOS (C) mRNA expression in spinal cords from IRF-1+/− (lanes 2–5) and IRF-1−/− (lanes 6 and 7) PL/J mice with (lanes 4–7) or without (lanes 2 and 3) clinical EAE. Lane 1 is a DNA size marker (φx174 DNA digested with HaeIII). IRF-1 expression was detected in normal spinal cord (lanes 2 and 3) and was increased in the spinal cords of IRF-1+/− mice with EAE (lanes 4 and 5). No PCR product was observed in IRF-1−/− samples (lanes 6 and 7). iNOS mRNA was detected in spinal cords from IRF-1+/− (lanes 4 and 5) and IRF-1−/− (lane 6) mice with EAE. PCR reactions were run 26 cycles for IRF-1 and β-actin, and 36 cycles for iNOS. Clinical scores at the time of tissue preparation were the following: lane 4, grade 3.5; lane 5, grade 4; lane 6, grade 2.5; lane 7, grade 3.5.
Mentions: IRF-1 plays an important role in the induction of iNOS (9–11), and the resulting NO production in macrophages and other cells is considered to be crucial in promoting inflammation (12). To examine the expression of IRF-1 and iNOS in inflamed tissues, RT-PCR of mRNA from spinal cord (EAE) and joint tissue (CIA) of IRF-1+/− mice with or without clinical disease was carried out. IRF-1 mRNA was detected both in normal spinal cord (Fig. 5, lanes 2 and 3), and in cells from spinal cords with clinical EAE (lane 4, score 3.5; lane 5, score 4). In fact, IFR-1 expression was enhanced in the latter, suggesting an upregulation of IRF-1 mRNA in infiltrating cells and/or resident cells in EAE spinal cord. iNOS mRNA expression was also detected in spinal cords of IRF-1+/− mice with EAE (Fig. 5, lanes 4 and 5). In contrast, IRF-1 expression was not detected in IRF-1−/− mice with clinical EAE (Fig. 5, lane 6, score 2.5; lane 7, score 3.5). However, iNOS mRNA was observed in an IRF-1−/− mouse with moderate EAE (Fig. 5, lane 6), which suggests that iNOS can be induced by an IRF-1-independent pathway. Caution should be exercised in interpreting this result, since >30 cycles of PCR were required to detect expression. In the case of CIA, similar levels of IRF-1 and iNOS mRNA expression were observed in four normal and two arthritic (severity grade 2) IRF-1+/− mice. However, no iNOS signal could be detected in joints from the three arthritic IRF-1−/− mice (two grade 1 and one grade 2).

Bottom Line: Interferon regulatory factor-1 (IRF-1) is a transcription factor that regulates interferon-induced genes and type I interferons.The incidence and severity of CIA were significantly decreased in IRF-1-/- mice compared with IRF-l +/- mice, as was the production of interferon (IFN)-gamma in lymph node cells.Expression of iNOS was also detected in inflamed spinal cords.

View Article: PubMed Central - PubMed

Affiliation: Amgen Institute, Department of Medical Biophysics, University of Toronto, Ontario, Canada.

ABSTRACT
Interferon regulatory factor-1 (IRF-1) is a transcription factor that regulates interferon-induced genes and type I interferons. Recently, studies of IRF-l-deficient mice have revealed that IRF-I regulates the induction of molecules that play important roles in inflammation, such as inducible nitric oxide synthase (iNOS) and interleukin-l beta-converting enzyme (ICE). To study the role of IRF-1 in autoimmunity, we investigated type II collagen-induced arthritis (CIA), and experimental allergic encephalomyelitis (EAE), in mice lacking IRF-1. The incidence and severity of CIA were significantly decreased in IRF-1-/- mice compared with IRF-l +/- mice, as was the production of interferon (IFN)-gamma in lymph node cells. Both IRF-l+/- and IRF-1-/- mice exhibited mild and transient disease after adoptive transfer of a type II collagen (CII)-specific T cell line together with sera from arthritic mice, but the IRF-1-/- mice were less severely affected than the IRF-1+/- mice. In addition, the incidence of EAE in IRF-1-/- mice was decreased as compared with IRF-1 +/- mice. Reverse transcription polymerase chain reaction showed that IRF-1 mRNA was constitutively expressed in the spinal cords of IRF-1+/- mice, and was upregulated in mice with clinical EAE. Expression of iNOS was also detected in inflamed spinal cords. These results suggest that IRF-I plays a key role in promoting inflammation and autoimmunity in CIA and EAE animal models.

Show MeSH
Related in: MedlinePlus