Human tolerogenic dendritic cells generated with protein kinase C inhibitor are optimal for functional regulatory T cell induction - A comparative study.

Tolerogenic dendritic cells (tDCs) are a promising therapeutic tool for specific induction of immunological tolerance. Human tDCs can be generated ex vivo using various compounds. However, the compound(s) most suitable for clinical application remain undefined. We compared the tolerogenic properties of tDCs treated with protein kinase C inhibitor (PKCI), dexamethasone, vitamin D3 (Vit D3), rapamycin (Rapa), interleukin (IL)-10, transforming growth factor (TGF)-ß, and a combination of peroxisome proliferator-activated receptor γ agonist and retinoic acid. All tDCs had a semi-mature DC phenotype. PKCI-, TGF-ß-, and Rapa-tDCs showed CCR7 expression and migration to CCL19, but other tDCs showed little or none. PKCI- and IL-10-tDCs induced functional regulatory T cells more strongly than other tDCs. The tolerogenic properties of all tDCs were stable against proinflammatory stimuli. Furthermore, PKCI-tDCs were generated from patients with rheumatoid arthritis and primary Sjögren's syndrome. Therefore, PKCI-tDCs showed the characteristics best suited for tolerance-inducing therapy.

Methotrexate-associated Lymphoproliferative Disease with Multiple Pulmonary Nodules in a Patient with Rheumatoid Arthritis.

Patients with rheumatoid arthritis (RA) treated with methotrexate (MTX) sometimes develop lymphoproliferative disease (LPD). MTX-associated LPD can affect nodal or extranodal sites, including the gastrointestinal tract, skin, lungs, kidneys and soft tissues, at almost equal frequency. However, it is very rare for MTX-associated LPD to manifest as multiple nodules in the lungs. We herein report the case of a RA patient who developed MTX-associated LPD with multiple pulmonary nodules during a 5-year course of MTX therapy.

Novel Autoantigens Associated with Lupus Nephritis.

Systemic lupus erythematosus (SLE) is characterized by production of a variety of autoantibodies. Although anti-double-stranded DNA (anti-dsDNA) antibodies contribute to the pathogenesis of lupus nephritis (LN), they are not sufficient for diagnosis and evaluation of disease activity. To obtain other autoantibodies associated with LN, we screened autoantigens reacting with the sera of LN patients by using an N-terminal biotinylated protein library created from a wheat cell-free protein production system. We screened 17 proteins that showed higher positive signals in the active phase than in the inactive phase of SLE, and higher positive signals in the serum of SLE patient with nephritis than in that of patient without nephritis. Of these, two LN-associated autoantigens, ribosomal RNA-processing protein 8 (RRP8) and spermatid nuclear transition protein 1 (TNP1) were identified by immunoprecipitation and immunofluorescence of renal tissues. Circulating anti-RRP8 and anti-TNP1 autoantibodies were recognized and deposited as an immune complex (IC) in glomeruli. IC was deposited preferentially in glomeruli rather than in other organs in C57BL/6 mice injected with RRP8 or TNP1. ELISA analysis of sera from patients with various rheumatic diseases demonstrated reactivity for RRP8 and TNP1 in 20% and 14.7% of SLE patients, respectively, whereas there was little or no reactivity in patients with other rheumatic diseases. Among SLE patients, 63.6% and 45.5% of those with LN were positive for anti-RRP8 and anti-TNP1 antibodies, compared with 12.5% and 9.4% of SLE patients without nephritis, respectively. Both proteins are cationic, and their respective antibodies did not cross-react with dsDNA. These proteins released from apoptotic cells form ICs with each autoantibody, and their ICs may become trapped at anionic sites in the glomerular basement membrane, leading to deposition in glomeruli. These autoantibodies may be useful for prediction of LN in subsets of SLE patients who are negative for anti-dsDNA antibodies.

Protein kinase C inhibitor generates stable human tolerogenic dendritic cells.

Tolerogenic dendritic cells (DCs) are a promising tool for a specific form of cellular therapy whereby immunological tolerance can be induced in the context of transplantation and autoimmunity. From libraries of bioactive lipids, nuclear receptor ligands, and kinase inhibitors, we screened conventional protein kinase C inhibitors (PKCIs) bisindolylmaleimide I, Gö6983, and Ro32-0432 with strong tolerogenic potential. PKCI-treated human DCs were generated by subjecting them to a maturation process after differentiation of immature DCs. The PKCI-treated DCs had a semimature phenotype, showing high production of IL-10, and efficiently induced IL-10-producing T cells and functional Foxp3(+) regulatory T cells from naive CD4(+) T cells, thus eliciting a strong immunosuppressive function. They also showed CCR7 expression and sufficient capacity for migration toward CCR7 ligands. Additionally, PKCI-treated DCs were highly stable when exposed to inflammatory stimuli such as proinflammatory cytokines or LPS. Conventional PKCIs inhibited NF-κB activation of both the canonical and noncanonical pathways of DC maturation, thus suppressing the expression of costimulatory molecules and IL-12 production. High production of IL-10 in PKCI-treated DCs was due to not only an increase of intracellular cAMP, but also a synergistic effect of increased cAMP and NF-κB inhibition. Moreover, PKCI-treated mouse DCs that had properties similar to PKCI-treated human DCs prevented graft-versus-host disease in a murine model of acute graft-versus-host disease. Conventional PKCI-treated DCs may be useful for tolerance-inducing therapy, as they satisfy the required functional characteristics for clinical-grade tolerogenic DCs.

Sustained elevation of interleukin-33 in sera and synovial fluids from patients with rheumatoid arthritis non-responsive to anti-tumor necrosis factor: possible association with persistent IL-1ß signaling and a poor clinical response.

Although TNF inhibitors have dramatically improved the outcome of patients with rheumatoid arthritis, 30-40% of patients do not respond well to them and treatment needs to be changed. In an effort to discriminate good and poor responders, we focused on the change in serum and synovial fluid levels of interleukin (IL-) 33 before and after treatment with TNF inhibitors. They were also measured in synovial fluids from 17 TNF inhibitor-naïve patients, and fibroblast-like synoviocytes (FLS) in-culture from 6 patients and correlated with various pro-inflammatory cytokines. Serum levels of IL-33 at 6 months after treatment decreased significantly in responders, while they did not change in non-responders. Synovial fluid levels of IL-33 in 6 patients under treatment with TNF inhibitors stayed high in 3 who were refractory and slightly elevated in 2 moderate responders, while they were undetectable in one patient under remission. Among inflammatory cytokines measured in 17 synovial fluids from TNF inhibitor-naïve patients, levels of IL-33 showed a significant positive correlation only to those of IL-1ß. IL-1ß increased IL-33 expression markedly in FLS in vitro, compared to TNF-α. IL-1ß might be inducing RA inflammation through producing pro-inflammatory IL-33 in TNF inhibitor-hypo-responders. Sustained elevation of serum and/or synovial levels of IL-33 may account for a poor response to TNF inhibitors, although how TNF inhibitors affect the level of IL-33 remains to be elucidated.

Influence of antibodies against infliximab and etanercept on the treatment effectiveness of these agents in Japanese patients with rheumatoid arthritis.

We investigated the influence of antibodies against infliximab and etanercept on the serum trough levels of these agents and the influence of these antibodies on the effectiveness of treatment in patients with rheumatoid arthritis treated with these agents. Forty patients treated with infliximab for 54 weeks and 40 patients treated with etanercept for 32 weeks were enrolled. They were divided into responder and non-responder groups. Serum trough levels of and antibodies against these agents were measured by enzyme-linked immunosorbent assay or radioimmunoassay. Of the 40 patients treated with infliximab, 14 (35%) had anti-infliximab antibodies. Serum trough levels were significantly lower in the non-responder group (14 patients) than in the responder group (26 patients) 6 weeks after initiation of infliximab (p < 0.05). Conversely, titers of anti-infliximab antibody were significantly higher in the non-responder group than in the responder group between 6 and 38 weeks after initiation of infliximab (p < 0.05). Anti-etanercept antibodies were not detected in any patients on etanercept. Serum trough levels of etanercept were not significantly different between the responder (31 patients) and non-responder groups (9 patients). It seems that the appearance of anti-infliximab antibodies might decrease infliximab serum concentrations and, thereby, reduce the agent's effectiveness. The clinical efficacy of etanercept does not appear to be affected by the serum concentrations if it is administered at standard doses.

Low level of seroconversion after a novel influenza A/H1N1/2009 vaccination in Japanese patients with rheumatoid arthritis in the 2009 season.

We examined change in the antibody titre against pandemic influenza A/H1N1/2009 before and after vaccination in Japanese patients with rheumatoid arthritis. This observational study was conducted with the participation of five hospitals in Japan. A total of 89 patients with rheumatoid arthritis were included in this study. The seroprotection and seroresponse rates to vaccination with the pandemic influenza A/H1N1/2009 vaccine were analysed. The seroprotection rates prior to the vaccination were 5.6% in the Japanese patients with rheumatoid arthritis. The seroprotection rates after subcutaneous vaccination were 55.1%. The seroresponse rate after subcutaneous vaccination was 50.6% in the patients with rheumatoid arthritis. Both the seroprotection and seroresponse rates obtained after the vaccination with the pandemic influenza A/H1N1/2009 vaccine were low in Japanese patients with rheumatoid arthritis. We should realise that a vaccination against this newly emerged influenza virus may protect only half of the Japanese patients with rheumatoid arthritis in a real world.

Healthcare-associated infections in rheumatology in Japan.

Prospective observational study was performed to elucidate the incidence and characteristics of healthcare-associated infections in a university hospital for rheumatology care. In this study, a total of 1,226 patients were prospectively enrolled between March 2004 and February 2006 and between April 2008 and December 2008. Healthcare-associated infection was defined as an infection developing after the third day of admission to the rheumatology ward. We detected the following 54 healthcare-associated infections in 49 patients: respiratory tract infection, 14 cases; Clostridium difficile infection, 2 cases; urinary tract infection, 4 cases; bloodstream infection, 9 cases; skin infection, 2 cases; reactivation of latent cytomegalovirus infection, 6 cases; herpes zoster infection, 5 cases; Candida infection, 7 cases; others, 4 cases. The incidence rate of respiratory tract infection was the highest. Methicillin-resistant Staphylococcus aureus was the causative bacterium in 21% of respiratory tract infections cases. Bloodstream infection due to the insertion of a catheter and opportunistic infection by a latent virus were also occurred commonly. Respiratory tract infection, bloodstream infection and opportunistic infection by a latent virus were the most common causes of healthcare-associated infection in rheumatology. It is important to pay more attention to healthcare-associated infection.

Lysophosphatidylcholine enhances the suppressive function of human naturally occurring regulatory T cells through TGF-ß production.

Naturally occurring CD4(+)CD25(+) regulatory T cells (nTregs) play a pivotal role in the maintenance of self-tolerance and immune homeostasis. To gain insight into the mechanism of action of nTregs in pathological and physiological immune responses, it is important to analyze bioactive molecules that modulate the maintenance and function of nTregs. From a library of bioactive lipids, we obtained lysophosphatidylcholine (LPC) as a molecule that enhanced the Foxp3 expression and suppressive function of human nTregs significantly in comparison with those of DMSO-treated nTregs (control). The expression levels of TGF-ß1 mRNA and protein in LPC-treated nTregs were significantly higher than those in control nTregs. After treatment with anti-TGF-ß1 antibody, the increases in Foxp3 expression and the suppressive properties of LPC-treated nTregs returned to the levels observed in control nTregs. These findings indicate that LPC enhances Foxp3 expression and the suppressive function of nTregs through TGF-ß1 produced by nTregs themselves. Experimental knockdown of G2A and GPR4 showed that this LPC-induced TGF-ß1 expression in nTregs was due to G2A signaling, and did not involve GPR4. Moreover, JNK was a major contributor to LPC-induced TGF-ß1 expression in nTregs, although LPC activated MAPKs including ERK1/2, p38 MAPK, and JNK via G2A. LPC is a bioactive lysolipid highly abundant in the circulation. Therefore, LPC may contribute to the maintenance and function of human nTregs in vivo.

Involvement of afadin in barrier function and homeostasis of mouse intestinal epithelia.

Afadin interacts with the cytoplasmic region of nectins, which are immunoglobulin-like cell adhesion molecules at adherens junctions, and links them to the actin cytoskeleton. Afadin regulates activities of cells in culture such as directional motility, proliferation and survival. We used Cre-loxP technology to generate mice conditionally lacking afadin specifically in the intestinal epithelia after birth. The loss of afadin caused increased paracellular permeability in the intestinal mucosa and enhanced susceptibility to the tissue destruction induced by dextran sulfate sodium. The junctional architecture of the intestinal epithelia appeared to be preserved, whereas the deficiency of afadin caused the mislocalization of nectin-2 and nectin-3 from adherens junctions to basolateral membrane domains but not that of other components of apical junctions. By contrast, such phenotypic changes were undetected in mice lacking nectin-2, nectin-3 or both. These findings suggest that afadin plays crucial roles, independently of the role as the nectin-afadin module, in barrier function and homeostasis of the intestinal epithelia once the epithelial structure has been established.

IKKε regulates cell elongation through recycling endosome shuttling.

IKK-related kinases are key regulators of innate immunity and oncogenesis. While their effects on transcription are well characterized, their cytoplasmic functions remain poorly understood. Drosophila IKK-related kinase, IKKɛ, regulates cytoskeletal organization and cell elongation. Here, we demonstrate that IKKɛ is activated locally at the tip of growing mechanosensory bristles and regulates the rapid shuttling of recycling endosomes, independent of its roles in F-actin organization and caspase signaling. IKKɛ regulates the localization of recycling endosome regulators Rab11 and Dynein and phosphorylates their adaptor molecule, Nuclear fallout (Nuf). Nuf's negative regulation by IKKɛ suggests that local activation of IKKɛ inhibits Dynein on incoming recycling endosomes, converting them for outward transport. Mammalian IKK-related kinases also regulate the recycling endosomes' distribution by phosphorylating the Nuf homolog Rab11-FIP3. Our results establish an evolutionarily conserved function of IKK-related kinases in regulating recycling endosome dynamics and point to a key role of endosome dynamics in cell morphogenesis.

[Management of elderly-onset rheumatoid arthritis].

In addition to population-growth in the elderly, development of new therapeutic agents for rheumatoid arthritis (RA) contributes to an increase in the number of elderly patients with RA. It is also reported that the age of RA onset is going higher. Elderly-onset RA (EORA) is defined as RA developing after the age of 60 years. In RA patients, significant damage can be detected radiographically within the first 2 years after the initial presentation of symptoms; therefore, appropriate treatment should be administered at the earliest. Meanwhile, caution should be exercised in prescribing disease-modifying antirheumatic drugs (DMARDs) to elderly patients because the associated risk of adverse effects and toxicity is elevated in the elderly. However, excessive caution may prevent elderly patients from being implemented the ideal therapy. Compared to young patients with RA, patients with EORA are less frequently treated with biological agents or multiple DMARDs treatment and more frequently treated with prednisone. Some patients with EORA do not receive optimal treatment during the early stage of RA, when the disease is highly active and joint destruction rapidly progresses. EORA should be treated with appropriate DMARDs instead of corticosteroids in order to maintain the risk of infection minimal and the patients' physical function maximal.

Cv2, functioning as a pro-BMP factor via twisted gastrulation, is required for early development of nephron precursors.

The fine-tuning of BMP signals is critical for many aspects of complex organogenesis. In this report, we show that the augmentation of BMP signaling by a BMP-binding secreted factor, Crossveinless2 (Cv2), is essential for the early embryonic development of mammalian nephrons. In the Cv2-null mouse, the number of cap condensates (clusters of nephron progenitors, which normally express Cv2) was decreased, and the condensate cells exhibited a reduced level of aggregation. In these Cv2(-/-) condensates, the level of phosphorylated Smad1 (pSmad1) was substantially lowered. The loss of a Bmp7 allele in the Cv2(-/-) mouse enhanced the cap condensate defects and further decreased the level of pSmad1 in this tissue. These observations indicated that Cv2 has a pro-BMP function in early nephrogenesis. Interestingly, the renal defects of the Cv2(-/-) mutant were totally suppressed by a null mutation of Twisted gastrulation (Tsg), which encodes another BMP-binding factor, showing that Cv2 exerts its pro-BMP nephrogenic function Tsg-dependently. By using an embryonic kidney cell line, we presented experimental evidence showing that Cv2 enhances pro-BMP activity of Tsg. These findings revealed the molecular hierarchy between extracellular modifiers that orchestrate local BMP signal peaks in the organogenetic microenvironment.