Masafumi Sugiyama

Retinoic Acid Reduces Autoimmune Renal Injury and Increases Survival in NZB/W F1 Mice

Retinoic acids, a group of natural and synthetic vitamin A derivatives, have potent antiproliferative and anti-inflammatory properties. Recently, retinoic acids were reported to inhibit Th1 cytokine production. We investigated the effects of retinoic acid on lupus nephritis in a model of NZB/NZW F1 (NZB/W F1) mice. Three-month-old NZB/W F1 mice were separated into two groups: one treated with all-trans-retinoic acid (ATRA; 0.5 mg i.p., three times weekly for 7 mo) and one with saline as a control. Compared with controls, ATRA-treated mice survived longer and exhibited a significant reduction of proteinuria, renal pathological findings including glomerular IgG deposits, and serum anti-DNA Abs. Splenomegaly was less marked in the treated mice than in controls. Transcripts encoding IFN-γ, IL-2, and IL-10 in splenic CD4+ T cells were significantly reduced in treated mice compared with controls. We conclude that treatment with ATRA in SLE-prone NZB/W F1 mice significantly alleviates autoimmune renal disorder and prolongs survival; this may thus represent a novel approach to the treatment of patients with lupus nephritis.

Blockade of IL-18 Receptor Signaling Delays the Onset of Autoimmune Disease in MRL-Faslpr Mice

Autoimmune disease in Fas-deficient MRL-Faslpr mice is dependent on infiltrating autoreactive leukocytes and autoantibodies, and IFN-γ plays an important role in the pathogenesis. As IL-18 is capable of inducing IFN-γ production in T cells, we hypothesized that signaling through IL-18R is involved in the pathogenesis. To investigate the impact of IL-18 in this autoimmune disease, we generated an MRL-Faslpr strain deficient in IL-18Rα. Compared with the wild-type strain, IL-18Rα-deficient MRL-Faslpr mice survived longer and showed a significant reduction in renal pathology, including glomerular IgG deposits, proteinuria, and serum anti-DNA Abs. Intrarenal transcripts encoding IFN-γ, TNF-α, IL-12, and IL-10, which have been linked to nephritis, were all markedly reduced. Skin lesions, lymphadenopathy, and lung pathology characteristic of the MRL-Faslpr mouse disease were diminished in IL-18Rα-deficient MRL-Faslpr mice. Thus, we conclude that IL-18Rα signaling is critical to the pathogenesis of autoimmune disease in MRL-Faslpr mice.

The beneficial effects of treatment with all-trans-retinoic acid plus corticosteroid on autoimmune nephritis in NZB/WF1 mice

Corticosteroids are highly effective anti‐inflammatory or immunosuppressive drugs used commonly to treat human systemic lupus erythematosus (SLE). All‐trans‐retinoic acid (ATRA), which belongs to a class of retinoids that exert immunomodulatory and anti‐inflammatory functions, can also suppress the development of lupus nephritis in an animal model. However, both agents can inflict serious adverse effects. Here, we have asked whether ATRA can serve as a steroid‐sparing drug in the treatment of lupus nephritis. To examine the efficacy of combining predonisolone (PSL) with ATRA, we treated intraperitoneally New Zealand black/white F1 (NZB/W F1) mice with PSL, ATRA or both agents. Survival rate and proteinuria were determined once a month. Cytokine and anti‐DNA antibody production were determined by enzyme‐linked immunosorbent assay (ELISA) and reverse transcription‐polymerase chain reaction (RT‐PCR). Renal histopathology was observed by haematoxylin and periodic acid Schiff (PAS), immunoperoxidase and immunohistochemical assay. Survival rate and proteinuria were improved in all experimental groups, and were much improved in the mice receiving the combination of ATRA and PSL (P < 0·05). A single administration of ATRA reduced the Th1 [interleukin (IL)‐2, interferon (IFN)‐γ and IL‐12], and a Th2 (IL‐4) cytokine level, as effectively as administration of PSL. ATRA also suppressed the expression of inducible nitric oxide synthetase (iNOS) and monocyte chemoattractant protein‐1 (MCP‐1) in the kidney. The combination of PSL and ATRA significantly reduced IgG2 (especially IgG2b)‐specific anti‐DNA antibody levels in comparison with administration of either agent alone. These data suggest that ATRA might have the potential to act as a new therapeutic and steroid‐sparing drug against lupus nephritis.

Successful Treatment With Retinoids in Patients With Lupus Nephritis

Lupus nephritis is a major manifestation of systemic lupus erythematosus. Treatment with such immunosuppressive agents as corticosteroids or cyclophosphamide can decrease the progression of lupus nephritis; however, these agents have potentially severe adverse reactions. Therefore, the development of new drugs with fewer side effects is needed. Here, we report 2 patients with lupus that were treated successfully with retinoids. Initially, both patients were treated with 60 mg/d of prednisolone. However, nephrotic syndrome was not improved. Subsequently, treatment with 10 mg/d of all-trans-retinoic acid was started orally and elicited a good response, showing a decrease in proteinuria. Although additional controlled clinical studies are needed to confirm these findings, we suggest that therapy using retinoids may represent a novel approach to the treatment of patients with lupus nephritis.

Survival study by organ disorders in 306 Japanese patients with systemic lupus erythematosus: results from a single center

Survival rate and causes of death according to the period of diagnosis and four accompanying organ disorders were analyzed in 306 Japanese patients with systemic lupus erythematosus. The survival rate was gradually improved, and the survival rate during 5- and 10-year periods of the patients diagnosed in 1990–2004 was 94 and 92%, 20-year period of those in 1980–1989 was 77%, 30-year period of those in 1975–1979 was 71%, respectively. Survival rate of those with serositis, pulmonary hypertension, and positive family history tended to be reduced, while that of the cases with neuropsychiatric disorder and renal disorder was significantly reduced. Overlapping of these organ disorders was an important factor for a poor prognosis. Bronchopneumonia and cerebrovascular accidents were frequent causes of death, and treatment for anti-phospholipid antibody syndrome and life-style diseases such as hypertension and arteriosclerosis was thought to be important for a good outcome.

Predominant inhibition of Th1 cytokines in New Zealand black/white F1 mice treated with FK506.

The T‐helper 1/T‐helper 2 (Th1/Th2) cell balance was examined in 6‐month‐old New Zealand black/white F1 (B/WF1) mice treated with an immunosuppressive agent, FK506. The survival rate of mice treated with 10 mg/kg/day of FK506 was 7/8, while that of those treated with 2.5 mg/kg/day was 5/8, and 4/8 after treatment for 8 weeks with placebo. Proteinuria, which was already positive in all mice before the treatment, in the seven of eight mice treated with 10 mg/kg/day remained mildly positive (≤1+), while seven of eight mice treated with 2.5 mg/kg/day and six of eight mice treated with the placebo showed severe proteinuria (≥2+). Pathological changes in the kidneys of mice treated with 10 mg/kg/day of FK506 were less severe than in mice treated with the placebo or 2.5 mg/kg/day of FK506. Expression of mRNA was unchanged for all cytokines determined in the groups treated with 2.5 mg/kg/day of FK506 or placebo. In contrast, expression of mRNA for interleukin (IL)‐2, and interferon (IFN)‐γ was suppressed, while that for IL‐4 and IL‐10 was not suppressed in the group treated with 10 mg/kg of FK506. The serum levels of IgG‐class anti‐DNA antibodies, which had been elevated before the treatment, were suppressed — especially in the IgG2a subclass — and the deposition of IgG2a and IgG2b in the glomeruli was reduced in the group treated with 10 mg/kg/day of FK506 compared with the other groups. These findings suggest that an improvement in the lupus nephritis of 6‐month‐old B/WF1 mice induced by FK506 might be associated with a predominant inhibition of Th1 cytokine.

Effect of combining ACE inhibitor and statin in lupus-prone mice.

MRL-Fas(lpr) mice spontaneously develop a systemic autoimmune disease resembling human systemic lupus erythematosus. The glomerulonephritis in MRL-Fas(lpr) mice is mediated by autoantibodies and autoreactive lymphocytes. To investigate the effect of combination therapy by angiotensin-converting enzyme inhibitor (ACEI) and hydroxymethylglutaryl-coenzyme A reductase inhibitor (statin) for lupus nephritis, we treated MRL-Fas(lpr) mice with imidapril, pravastatin or both agents. Compared with other groups, the mice treated by combination therapy survived longer and showed a significant reduction in proteinuria, renal pathology, including glomerular IgG deposit, and serum anti-DNA Ab. Furthermore, monocyte chemoattractant protein-1 (MCP-1) in the kidney was reduced significantly in the combination therapy group, compared with that in the control group. We conclude that combination therapy with ACEI and statin for MRL-Fas(lpr) mice significantly alleviates autoimmune renal disorder and prolongs survival. These results suggest that combination therapy by ACEI and statin may represent a new approach to the treatment of patients with lupus.

All-trans-retinoic acid suppresses interferon-γ and tumor necrosis factor-α; a possible therapeutic agent for rheumatoid arthritis

Objectives: To study the effects of all-trans-retinoic acid (ATRA), we determined the proliferation and cytokine production by peripheral blood mononuclear cells (PBMCs) and CD4+ T cells in healthy volunteers and patients with rheumatoid arthritis (RA), and explored the possibility of using ATRA as a therapeutic agent for autoimmune diseases. Methods: Proliferation of these cells was determined by modified MTT assay, and expression of CC chemokine receptors 4 (CCR4) and CCR5 was determined by flow cytometry. Production and expression of interferon (IFN)-γ, interleukin (IL)-2, IL-4, and tumor necrosis factor (TNF)-α was determined by Enzyme-Linked Immunosorbent Assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). The presence of STAT6 protein was determined by Western blot analysis. Results: ATRA did not affect the proliferation or production of IL-2 and IL-4. We did not detect STAT6 protein, and saw no evidence of the differentiation of PBMCs to Th1 or Th2 cells. In contrast, ATRA suppressed the production of IFN-γ and TNF-α significantly. There were no significant differences between the healthy volunteers and RA patients. Conclusions: ATRA was demonstrated to affect the cytokine production of IFN-γ and TNF-α. ATRA might be useful in the treatment of autoimmune diseases such as RA.

Therapeutic Effect of Retinoic Acid on Unilateral Ureteral Obstruction Model

Background: Retinoic acids, a group of natural and synthetic vitamin A derivatives, have potent anti-proliferative, anti-inflammatory and anti-fibrotic properties. We investigated the therapeutic effect of all-trans-retinoic acid (ATRA) on unilateral ureteral obstruction (UUO) model mice. Methods: First, to evaluate the prophylactic effect, we administered 0.5 mg of ATRA for 3 days before UUO (UUO ATRA). Then, to evaluate the therapeutic effects, we administered 0.5 mg of ATRA 3 days after UUO (Day3 ATRA). We compared the histological changes and immunostaining of macrophages, α-smooth muscle actin (α-SMA) and collagen I, and mRNA expression of monocyte chemotactic protein-1 (MCP-1), transforming growth factor (TGF)-β1 and TGF-β R-II by RT-PCR 7 days after UUO. Results: In the UUO ATRA and Day3 ATRA groups, we observed a significant improvement in histological and immunological findings, including macrophage infiltration and improved expression of MCP-1, TGF-β1, α-SMA and collagen I compared with the UUO Day7 group. Conclusion: ATRA treatment is not only an effective prophylactic strategy, but also a therapeutic strategy for the treatment of progressive renal fibrosis in diseased kidneys.

Dysregulation of the granulocyte-macrophage colony stimulating factor receptor is one of the causes of defective expression of CD80 antigen in systemic lupus erythematosus

CD80 and CD86, expressed on the antigen-presenting cells (APCs) provide costimulatory signals for T lymphocytes. Recently, defective expression of CD80 has been reported in systemic lupus erythematosus (SLE) although its mechanism is unclear. Here, expression of the B7 antigens induced by interferon-g, interleukin-4 or granulocyte-macrophage stimulating-factor (GM-CSF) along the differentiation process of APCs was investigated. In contrast to CD86, expression of CD80 on the CD14‡ cells induced by GM-CSF was reduced in SLE. GM-CSF receptor (GMCSFR) was down-regulated by GM-CSF or phorbol 12-myristate 13-acetate in both of the normal controls and SLE patients, while this change was more remarkable in the latter. In the presence of 1-(5-isoquinolinsulfonyl)-2-methylpiperazine, an inhibitor of protein kinase C, the PMA-induced down-regulation of GM-CSFR was reversed in the normal controls but not in SLE. These data suggest that dysregulation of the GM-CSFR might be associated with the defective expression of CD80, leading to dysfunction of the APCs in SLE.