1,25-dihydroxy Vitamin D3 and Interleukin-6 Blockade Synergistically Regulate Rheumatoid Arthritis by Suppressing Interleukin-17 Production and Osteoclastogenesis

BACKGROUND: Immune cells express the vitamin (vit) D receptor, and vit D is a potent immune-modulator. A negative correlation between serum vit D levels and rheumatoid arthritis (RA) disease activity has been reported. Therefore, we aimed to investigate if the sufficient serum vit D level is helpful to control disease activity in RA patients treated with interleukin (IL)-6 receptor antibody tocilizumab.METHODS: RA patients taking tocilizumab were enrolled, and data were collected retrospectively. Disease activity scores (DAS) 28, serum vit D levels, modified Sharp scores of hand X-ray at the time of tocilizumab initiation, and follow-up data were analysed. Peripheral blood mononuclear cells were differentiated into T-helper (Th) 17 or osteoclasts in the presence of various concentrations of tocilizumab and/or 1,25(OH)₂D. Th17 proportions were analysed by fluorescence-activated cell sorting. Supernatant cytokine levels were determined by enzyme-linked immunosorbent assay.RESULTS: Among 98 RA patients taking tocilizumab, 34 (34.7%) had sufficient serum 25(OH)D levels (≥ 30 ng/mL) when tocilizumab was initiated. At 24 weeks, vit D sufficient patients had greater DAS28 reduction (64.6% ± 15.5% vs. 52.7% ± 20.7%, P = 0.004), and lower disease activity (91.2% vs. 70.3%, P = 0.018) or remission (82.4% vs. 57.8%, P = 0.014). These differences in DAS28 reduction and the proportion of patients with remission persisted at 48 weeks. However, there was no significant difference in hand and wrist erosion progression. In vitro, tocilizumab and 1,25(OH)₂D treatment synergistically suppressed IL-17 production and osteoclastogenesis.CONCLUSION: RA patients treated with IL-6 antibody show a better response when they have sufficient serum vit D. Tocilizumab and 1,25(OH)₂D synergistically suppress IL-17 production and osteoclast differentiation in RA patients.

1,25-dihydroxy Vitamin D3 and Interleukin-6 Blockade Synergistically Regulate Rheumatoid Arthritis by Suppressing Interleukin-17 Production and Osteoclastogenesis

BACKGROUND@#Immune cells express the vitamin (vit) D receptor, and vit D is a potent immune-modulator. A negative correlation between serum vit D levels and rheumatoid arthritis (RA) disease activity has been reported. Therefore, we aimed to investigate if the sufficient serum vit D level is helpful to control disease activity in RA patients treated with interleukin (IL)-6 receptor antibody tocilizumab.@*METHODS@#RA patients taking tocilizumab were enrolled, and data were collected retrospectively. Disease activity scores (DAS) 28, serum vit D levels, modified Sharp scores of hand X-ray at the time of tocilizumab initiation, and follow-up data were analysed. Peripheral blood mononuclear cells were differentiated into T-helper (Th) 17 or osteoclasts in the presence of various concentrations of tocilizumab and/or 1,25(OH)₂D. Th17 proportions were analysed by fluorescence-activated cell sorting. Supernatant cytokine levels were determined by enzyme-linked immunosorbent assay.@*RESULTS@#Among 98 RA patients taking tocilizumab, 34 (34.7%) had sufficient serum 25(OH)D levels (≥ 30 ng/mL) when tocilizumab was initiated. At 24 weeks, vit D sufficient patients had greater DAS28 reduction (64.6% ± 15.5% vs. 52.7% ± 20.7%, P = 0.004), and lower disease activity (91.2% vs. 70.3%, P = 0.018) or remission (82.4% vs. 57.8%, P = 0.014). These differences in DAS28 reduction and the proportion of patients with remission persisted at 48 weeks. However, there was no significant difference in hand and wrist erosion progression. In vitro, tocilizumab and 1,25(OH)₂D treatment synergistically suppressed IL-17 production and osteoclastogenesis.@*CONCLUSION@#RA patients treated with IL-6 antibody show a better response when they have sufficient serum vit D. Tocilizumab and 1,25(OH)₂D synergistically suppress IL-17 production and osteoclast differentiation in RA patients.

Type I Interferon Increases Inflammasomes Associated Pyroptosis in the Salivary Glands of Patients with Primary Sjögren's Syndrome

Sjögren's syndrome (SS) is a chronic and systemic autoimmune disease characterized by lymphocytic infiltration in the exocrine glands. In SS, type I IFN has a pathogenic role, and recently, inflammasome activation has been observed in both immune and non-immune cells. However, the relationship between type I IFN and inflammasome-associated pyroptosis in SS has not been studied. We measured IL-18, caspase-1, and IFN-stimulated gene 15 (ISG15) in saliva and serum, and compared whether the expression levels of inflammasome and pyroptosis components, including absent in melanoma 2 (AIM2), NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), caspase-1, gasdermin D (GSDMD), and gasdermin E (GSDME), in minor salivary gland (MSG) are related to the expression levels of type I IFN signature genes. Expression of type I IFN signature genes was correlated with mRNA levels of caspase-1 and GSDMD in MSG. In confocal analysis, the expression of caspase-1 and GSDMD was higher in salivary gland epithelial cells (SGECs) from SS patients. In the type I IFN-treated human salivary gland epithelial cell line, the expression of caspase-1 and GSDMD was increased, and pyroptosis was accelerated in a caspase-dependent manner upon inflammasome activation. In conclusion, we demonstrate that type I IFN may contribute to inflammasome-associated pyroptosis of the SGECs of SS patients, suggesting another pathogenic role of type I IFN in SS in terms of target tissue -SGECs destruction.

1,25-dihydroxy Vitamin D3 and Interleukin-6 Blockade Synergistically Regulate Rheumatoid Arthritis by Suppressing Interleukin-17 Production and Osteoclastogenesis

BACKGROUND@#Immune cells express the vitamin (vit) D receptor, and vit D is a potent immune-modulator. A negative correlation between serum vit D levels and rheumatoid arthritis (RA) disease activity has been reported. Therefore, we aimed to investigate if the sufficient serum vit D level is helpful to control disease activity in RA patients treated with interleukin (IL)-6 receptor antibody tocilizumab.@*METHODS@#RA patients taking tocilizumab were enrolled, and data were collected retrospectively. Disease activity scores (DAS) 28, serum vit D levels, modified Sharp scores of hand X-ray at the time of tocilizumab initiation, and follow-up data were analysed. Peripheral blood mononuclear cells were differentiated into T-helper (Th) 17 or osteoclasts in the presence of various concentrations of tocilizumab and/or 1,25(OH)₂D. Th17 proportions were analysed by fluorescence-activated cell sorting. Supernatant cytokine levels were determined by enzyme-linked immunosorbent assay.@*RESULTS@#Among 98 RA patients taking tocilizumab, 34 (34.7%) had sufficient serum 25(OH)D levels (≥ 30 ng/mL) when tocilizumab was initiated. At 24 weeks, vit D sufficient patients had greater DAS28 reduction (64.6% ± 15.5% vs. 52.7% ± 20.7%, P = 0.004), and lower disease activity (91.2% vs. 70.3%, P = 0.018) or remission (82.4% vs. 57.8%, P = 0.014). These differences in DAS28 reduction and the proportion of patients with remission persisted at 48 weeks. However, there was no significant difference in hand and wrist erosion progression. In vitro, tocilizumab and 1,25(OH)₂D treatment synergistically suppressed IL-17 production and osteoclastogenesis.@*CONCLUSION@#RA patients treated with IL-6 antibody show a better response when they have sufficient serum vit D. Tocilizumab and 1,25(OH)₂D synergistically suppress IL-17 production and osteoclast differentiation in RA patients.

Type I Interferon Increases Inflammasomes Associated Pyroptosis in the Salivary Glands of Patients with Primary Sjögren's Syndrome

Sjögren's syndrome (SS) is a chronic and systemic autoimmune disease characterized by lymphocytic infiltration in the exocrine glands. In SS, type I IFN has a pathogenic role, and recently, inflammasome activation has been observed in both immune and non-immune cells. However, the relationship between type I IFN and inflammasome-associated pyroptosis in SS has not been studied. We measured IL-18, caspase-1, and IFN-stimulated gene 15 (ISG15) in saliva and serum, and compared whether the expression levels of inflammasome and pyroptosis components, including absent in melanoma 2 (AIM2), NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), caspase-1, gasdermin D (GSDMD), and gasdermin E (GSDME), in minor salivary gland (MSG) are related to the expression levels of type I IFN signature genes. Expression of type I IFN signature genes was correlated with mRNA levels of caspase-1 and GSDMD in MSG. In confocal analysis, the expression of caspase-1 and GSDMD was higher in salivary gland epithelial cells (SGECs) from SS patients. In the type I IFN-treated human salivary gland epithelial cell line, the expression of caspase-1 and GSDMD was increased, and pyroptosis was accelerated in a caspase-dependent manner upon inflammasome activation. In conclusion, we demonstrate that type I IFN may contribute to inflammasome-associated pyroptosis of the SGECs of SS patients, suggesting another pathogenic role of type I IFN in SS in terms of target tissue -SGECs destruction.

Circulating CCR7(lo)PD-1(hi) Follicular Helper T Cells Indicate Disease Activity and Glandular Inflammation in Patients with Primary Sjögren's Syndrome

Since primary Sjögren's syndrome (pSS) is an autoummune disease of B cell hyperactivity and pathologic autoantibody response, follicular helper T (Tfh) cells and follicular regulatory T (Tfr) cells are suggested to be key players in pSS. We examined subsets of Tfh and Tfr cells from the blood in pSS patients, and whether these subsets represent disease activity, glandular inflammation, or autoantibody responses in pSS. Circulating Tfh and Tfr cells, along with their specific subsets, were identified from the peripheral blood of 18 pSS patients and 14 age- and sex-matched healthy controls (HCs) using flow cytometry analysis. Blood Tfr and Tfh cell ratios were increased in pSS patients compared with HCs. The CCR7(lo)PD-1(hi) subset of circulating Tfh cells was increased in pSS patients with high degree of focal lymphocytic sialadenitis; whereas circulating Tfh cells did not differ between pSS patients and HCs. The frequency of CCR7(lo)PD-1(hi) Tfh cells was significantly correlated with disease activity scores and differentiated B cells. PD-1 expression on blood Tfh and Tfr cells showed positive correlations with IL-21 in pSS. Increasing trend of blood Tfr cells was observed in pSS patients, and blood Tfr cells (particularly Th1 and Th17 subsets) represented hypergammaglobulinemia in pSS. In summary, circulating CCR7(lo)PD-1(hi) Tfh cells indicated disease activity and glandular inflammation in pSS. Circulating Tfr cells, shifted toward Th1 and Th17 subsets, indicated ongoing IgG production in pSS. Subsets of circulating Tfh or Tfr cells could be biomarkers for disease monitoring and patient stratification in pSS.

The Therapeutic Effect of Sauchinone on Inflammatory Arthritis in Mice

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic inflammatory disease, mainly involving joints and bones. Sauchinone is an anti-inflammatory agent isolated from Saururus chinensis, which was used in oriental medicine. The aim of this study was to evaluate the therapeutic effect of sauchinone on inflammatory arthritis and underlying mechanism of anti-arthritic effect. METHODS: Mice with collagen induced arthritis (CIA) was intraperitoneally injected with sauchinone (20 mg/kg) or vehicle. The clinical and histological evaluations were performed with arthritis scoring and hematoxylin-eosin staining, respectively. CD4+ interleukin (IL) 17+ T cells were determined under Th17 skewing condition treated with sauchinone. To evaluate the effect of sauchinone on osteoclastogenesis, mice bone marrow macrophages (BMMs) and human peripheral blood mononuclear cells (PBMCs) were cultured with macrophage-colony stimulating factor and receptor activator of nuclear factor-κB ligand in the absence or presence of sauchinone. RESULTS: Sauchinone significantly attenuated the inflammatory arthritis in CIA mice both clinically and histologically. The proportion of Th17 cells were decreased with treatment with sauchinone in vivo and in vitro. The expressions of Th17 cell markers (IL-17 and retinoic acid receptor-related orphan receptor gamma t) and B cell markers (activation-induced cytidine deaminase) were downregulated in the presence of sauchinone. Sauchinone also suppressed the formation of tartrate-resistant acid phosphatase positive cells from mice BMMs and human PBMCs, and the expression of osteoclastogenic markers. CONCLUSION: Sauchinone alleviates inflammatory arthritis in mice through inhibition of Th17 differentiation and osteoclastogenesis. Sauchinone, one of traditional herbal medicine, could be a therapeutic candidate for the treatment of RA.