Increased Expression of Long Noncoding RNA LOC100506314 in T cells from Patients with Nonsegmental Vitiligo and Its Contribution to Vitiligo Pathogenesis.

This study aimed to identify the abnormal expression of long noncoding RNAs (lncRNAs) in T cells from patients with vitiligo and to investigate their functional roles in the immune system. Using microarray analysis, the expression levels of RNA transcripts in T cells from patients with vitiligo and controls were compared. We identified several genes and validated their expression levels in T cells from 41 vitiligo patients and 41 controls. The biological functions of the lncRNAs were studied in a transfection study using an RNA pull-down assay, followed by proteomic analysis and western blotting. The expression levels of 134 genes were significantly increased, and those of 142 genes were significantly decreased in T cells from vitiligo patients. After validation, six genes had increased expression, and three genes had decreased expression in T cells from patients with vitiligo. T-cell expression of LOC100506314 was increased in vitiligo, especially CD4+, but not CD8+ T cells. The expression levels of LOC100506314 in CD4+ T cells was positively and significantly associated with the severity of vitiligo. LOC100506314 was bound to the signal transducer and activator of transcription 3 (STAT3) and macrophage migration inhibitory factor (MIF). Enhanced expression of LOC100506314 inhibited the phosphorylation of STAT3, protein kinase B (AKT), and extracellular signal-regulated protein kinases (ERK), as well as the levels of nuclear protein of p65 and the expression of IL-6 and IL-17 in Jurkat cells and T cells from patients with vitiligo. In conclusion, this study showed that the expression of LOC100506314 was elevated in CD4+ T cells from patients with vitiligo and associated the severity of vitiligo. LOC100506314 interacted with STAT3 and MIF and inhibited IL-6 and IL-17 expression by suppressing the STAT3, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), AKT, and ERK pathways. Enhanced expression of LOC100506314 in T cells may be a potential treatment strategy for vitiligo.

Brain-Derived Neurotrophic Factor Suppressed Proinflammatory Cytokines Secretion and Enhanced MicroRNA(miR)-3168 Expression in Macrophages.

We investigated the role of brain-derived neurotrophic factor (BDNF) and its signaling pathway in the proinflammatory cytokines production of macrophages. The effects of different concentrations of BDNF on proinflammatory cytokines expression and secretion in U937 cell-differentiated macrophages, and human monocyte-derived macrophages were analyzed using enzyme-linked immunosorbent assay and real-time polymerase chain reaction. The CRISPR-Cas9 system was used to knockout p75 neurotrophin receptor (p75NTR), one of the BDNF receptors. Next-generation sequencing (NGS) was conducted to search for BDNF-regulated microRNA. A very low concentration of BDNF (1 ng/mL) could suppress the secretion of interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and IL-6 in lipopolysaccharide (LPS)-stimulated macrophages but did not change their mRNA expression. BDNF suppressed IL-1ß and IL-6 secretion in human monocyte-derived macrophages. In U937 cells, BDNF suppressed the phosphorylation of JNK and c-Jun. The p75NTR knockout strongly suppressed IL-1ß, IL-6, and TNF-α secretion in macrophages and LPS-stimulated macrophages. BDNF regulated the expression of miR-3168 with Ras-related protein Rab-11A as its target. In conclusion, BDNF suppressed proinflammatory cytokines secretion in macrophages and inhibited the phosphorylation of JNK. Knockout of p75NTR suppressed proinflammatory cytokines expression and secretion. BDNF upregulated the expression of miR-3168. The inhibition of p75NTR could be a potential strategy to control inflammation.

HLA-B*27 Heavy Chain Homo-Oligomers Promote the Cytotoxicity of NK Cells via Activation of PI3K/AKT Signaling.

Background and Objectives: Ankylosing spondylitis (AS) is a chronic inflammatory disease and is highly linked with the expression of the human leukocytic antigen-B*27 (HLA-B*27) genotype. HLA-B*27 heavy chain (B*27-HC) has an innate characteristic to slowly fold, resulting in the accumulation of the misfolded B*27-HC and the formation of homo-oligomeric B*27-HC molecules. The homo-oligomeric B*27-HC can act as a ligand of KIR3DL2. Interaction of the homo-oligomeric B*27-HC molecules with KIR3DL2 will trigger the survival and activation of KIR3DL2-positive NK cells. However, the effects of homo-oligomeric B*27-HC molecules associated with KIR3DL2 on the cytotoxic activity of NK cells and their cytokine expressions remain unknown. Materials and Methods: HLA-B*-2704-HC was overexpressed in the HMy2.C1R (C1R) cell line. Western blotting and quantitative RT-PCR were used to analyze the protein expression and cytokine expression, respectively, when C1R-B*-2704 cells that overexpress B*2704-HC were co-cultured with NK-92MI cells. Flow cytometry was used to analyze the cytotoxicity mediated by NK-92MI cells. Results: Our results revealed that NK-92MI cells up-regulated the expression of perforin and enhanced the cytotoxic activity via augmentation of PI3K/AKT signaling after co-culturing with C1R-B*2704 cells. Suppression of the dimerized B*27-HC formation or treatment with an inhibitor of PI3K, LY294002, or with an anti-B*27-HC monoclonal antibody can reduce the perforin expression of NK-92MI after co-culturing with C1R-B*-2704. Co-culturing with C1R-B*-2704 cells suppressed the TNF-α and IL6 expressions of NK-92MI cells. Conclusion: Stimulation of NK cell-mediated cytotoxicity by homo-oligomeric B*27-HC molecules may contribute to the pathogenesis of AS.

Increased Serum Levels of Brain-Derived Neurotrophic Factor Contribute to Inflammatory Responses in Patients with Rheumatoid Arthritis.

The aim of this study is to investigate the role of brain-derived neurotrophic factor (BDNF) in the inflammatory responses in patients with rheumatoid arthritis (RA). Serum levels of BDNF and the precursor form of BDNF (proBDNF) from 625 RA patients and 40 controls were analyzed using enzyme-linked immunosorbent assay. Effects of BDNF on the mitogen-activated protein kinase pathway were analyzed by Western blotting. Microarray analysis was conducted to search BDNF regulated gene expression in Jurkat cells, and the differentially expressed genes were validated using T cells from patients with RA and controls. Serum BDNF levels were significantly elevated in patients with RA compared with the controls. Low serum BDNF levels were found in RA patients with anxiety or receiving biologics treatment. BDNF (20 ng/mL) enhanced the phosphorylation of ERK, JNK, and c-Jun, but suppressed the phosphorylation of p38, whereas BDNF (200 ng/mL) enhanced the phosphorylation of ERK and p38. After validation, the expression of CAMK2A, MASP2, GNG13, and MUC5AC, regulated by BDNF and one of its receptors, NGFR, was increased in RA T cells. BDNF increased the IL-2, IL-17, and IFN-γ expression in Jurkat cells and IL-2 and IFN-γ secretion in activated peripheral blood mononuclear cells.

Identification of phostensin in association with Eps 15 homology domain-containing protein 1 (EHD1) and EHD4.

Phostensin (PTS) encoded by KIAA1949 is a protein phosphatase 1 (PP1)-binding protein. In order to explore the cellular functions of PTS, we have searched PTS-binding proteins by using co-immunoprecipitation in combination with shotgun proteomics. Here, we report two novel PTS-binding proteins, Eps 15 homology domain-containing protein 1 (EHD1) and EHD4. PTS associated with EHD proteins was also observed in GST pull-down assays. Immunofluorescence microscopy demonstrated that the complex was co-localized at the endocytic vesicles. EHD proteins have been known to play a critical role in regulation of endocytic transport. Overexpression of PTS-ß can attenuate the endocytic trafficking of transferrin.

The Essential Role of Peptidylarginine Deiminases 2 for Cytokines Secretion, Apoptosis, and Cell Adhesion in Macrophage.

OBJECTIVE: The study aims to investigate the functional roles of peptidylarginine deiminase 2 (PADI2) in macrophages. METHODS: The clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein-9 nuclease (Cas9) system was used to knockout PADI2 in U937 cells. U937 cells were introduced to differentiate macrophages and were stimulated with lipopolysaccharides (LPS). The protein expression of PADI2, PADI4, and citrullinated proteins were analyzed by Western blotting. The mRNA and protein levels of interleukin 1 beta (IL-1ß), IL-6, and tumor necrosis factor-alpha (TNF-α) were analyzed using RT-PCR and ELISA, respectively. Cell apoptosis was analyzed using flow cytometry. Cell adhesion assay was performed using a commercially available fibrinogen-coated plate. RESULTS: PADI2 knockout could markedly suppress the PADI2 protein expression, but not the PADI4 protein expression. PADI2 knockout decreased the protein levels of citrullinated nuclear factor κB (NF-κB) p65, but not those of citrullinated histone 3, resulting in the decreased mRNA expression levels of IL-1ß and TNF-α in the U937 cells and IL-1ß and IL-6 in the differentiated macrophages and the macrophages stimulated with LPS. The cytokines levels of IL-1ß, IL-6, and TNF-α were all dramatically decreased in the PADI2 knockout group compared with in the controls. PADI2 knockout prevented macrophages apoptosis via the decreased caspase-3, caspase-2, and caspase-9 activation. PADI2 knockout also impaired macrophages adhesion capacity through the decreased protein levels of focal adhesion kinase (FAK), phospho-FAK, paxillin, phospho-paxillin, and p21-activated kinase 1. CONCLUSION: This study showed that PADI2 could promote IL-1ß, IL-6, and TNF-α production in macrophages, promote macrophage apoptosis through caspase-3, caspase-2, and caspase-9 activation and enhance cell adhesion via FAK, paxillin, and PAK1. Therefore, targeting PADI2 could be used as a novel strategy for controlling inflammation caused by macrophages.

Modestly Elevated Serum Procalcitonin Levels in Patients with Rheumatoid Arthritis Free of Active Infection.

Background and objectives: To investigate the serum procalcitonin (PCT) levels among patients with rheumatoid arthritis (RA) without active infection compared with healthy controls and to understand the relationship of PCT with RA disease activity, and treatment received by patients. Materials and Methods: Patients aged 20 years and above with clinician-confirmed diagnosis of RA and healthy volunteers were included during regular outpatient visits, and those with active infection symptoms and signs were excluded. RA disease activity was measured using the Disease Activity Score-28 for Rheumatoid Arthritis with erythrocyte sedimentation rate (DAS28-ESR). Medications received by the patients were also recorded. Results: A total of 623 patients with RA and 87 healthy subjects were recruited in this study. The mean PCT were significantly higher in patients with RA (6.90 ± 11.81 × 10-3 ng/mL) compared with healthy controls (1.70 ± 6.12 × 10-3 ng/mL) (p < 0.001) and the difference remained statistically significant after adjusting for age and sex. In addition, multiple linear regression analysis showed that a lower rank-transformed PCT serum level was significantly correlated with the use of biologics (p = 0.017) and a high DAS28-ESR score (p = 0.028) in patients with RA. Conclusion: Patients with RA have a significantly higher serum PCT levels compared with healthy controls. The use of biologics and an active RA disease activity were associated with a lower level of PCT in patients with RA. Further investigation is required to determine the optimal cutoff value of PCT among patients with RA and its association with disease activity and biologic usage.

Dispersion of Poly(urea-formaldehyde)-Based Microcapsules for Self-Healing and Anticorrosion Applications.

An effective dispersant, oleyl phosphate (OP), for the dispersion of poly(urea-formaldehyde)-based microcapsules in a typical epoxy coating material is proposed. Based on electron microscopy observations and rheological and mechanical characterizations, it is observed that the addition of merely 0.5 wt % of OP is sufficient to obtain good dispersion of the microcapsules in the epoxy. In the self-healing and anticorrosion experiments, a microcapsule content of at least 15 wt % is required to efficiently restore the epoxy matrix and provide corrosion protection to underlying low-carbon steel when the particles are not dispersed; however, the amount of microcapsules required to obtain good self-healing and anticorrosion efficiencies can be greatly reduced to only 5 wt % when the microcapsules are dispersed by OP.

Targeted Delivery of the HLA-B∗27-Binding Peptide into the Endoplasmic Reticulum Suppresses the IL-23/IL-17 Axis of Immune Cells in Spondylarthritis.

Ankylosing spondylitis (AS) is highly associated with the expression of human leukocyte antigen-B27 (HLA-B∗27). HLA-B∗27 heavy chain (B27-HC) has an intrinsic propensity to fold slowly, leading to the accumulation of the misfolded B27-HC in the endoplasmic reticulum (ER) and formation of the HLA-B∗27 HC homodimer, (B27-HC)2, by a disulfide linkage at Cys-67. (B27-HC)2 displayed on the cell surface can act as a ligand of the killer-cell Ig-like receptor (KIR3DL2). (B27-HC)2 binds to KIR3DL2 of NK and Th17 cells and activates both cells, resulting in the activation of the IL-23/IL-17 axis to launch the inflammatory reaction in AS patients. However, activation of the IL-23/IL-17 axis originally derived from the HLA-B∗27 misfolding in the ER needs to be characterized. In this study, we delivered two HLA-B∗27-binding peptides, KRGILTLKY and SRYWAIRTR, into the ER by using a tat-derived peptide (GRKKRRQRRR)-His6-ubiquitin (THU) vehicle. Both peptides are derived from the human actin and nucleoprotein of influenza virus, respectively. Our results demonstrated that targeted delivery of both HLA-B∗27-binding peptides into the ER can promote the HLA-B∗27 folding, decrease the levels of (B27-HC)2, and suppress the activation of the IL-23/IL-17 axis in response to lipopolysaccharide. Our findings can provide a new therapeutic strategy in AS.

Increased Serum Levels of Anti-Carbamylated 78-kDa Glucose-Regulated Protein Antibody in Patients with Rheumatoid Arthritis.

The objective of this study was to investigate the presence and titer of anti-carbamylated 78-kDa glucose-regulated protein (anti-CarGRP78) antibody in serum from controls, and patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary Sjögren syndrome (pSS). Thirty-three RA patients, 20 SLE patients, 20 pSS patients, and 20 controls were enrolled from our outpatient clinic. GRP78 was cloned and carbamylated. Serum titers of anti- cyclic citrullinated peptides (anti-CCP), anti-GRP78, and anti-CarGRP78 were measured with an enzyme-linked immunosorbent assay. No differences in serum titers of anti-GRP78 antibody in patients with RA, SLE, or pSS compared with the controls were observed. Serum levels of anti-carGRP78 antibody in patients with RA, but not SLE or pSS, were significantly higher compared with the controls (OD405 0.15 ± 0.08 versus 0.11 ± 0.03, p = 0.033). There was a positive correlation between the serum levels of anti-GRP78 antibody, but not anti-CarGRP78 antibody, with the levels of anti-CCP antibody in patients with RA. Both anti-GRP78 and anti-carGRP78 antibodies failed to correlate with C-reactive protein levels in patients with RA. In conclusion, we demonstrated the presence of anti-CarGRP78 antibody in patients with RA. In addition, the serum titer of anti-CarGRP78 antibody was significantly elevated in patients with RA compared with the controls. Anti-CarGRP78 antibody could also be detected in patients with SLE or pSS.

Aberrant T cell expression of Ca2+ influx-regulated miRNAs in patients with systemic lupus erythematosus promotes lupus pathogenesis.

OBJECTIVE: The aim of this study was to investigate the pathogenic role of calcium (Ca(2+)) influx-regulated microRNAs (miRNAs) in T cells from patients with SLE. METHODS: Expression profiles of 270 human miRNAs in Jurkat cells co-cultured with or without ionomycin were analysed by real-time PCR. Differential expression of miRNAs in T cell samples from 28 patients with SLE (SLE T cells) and 20 healthy controls were investigated using western blot analysis of proteins expressed by respective miRNA target transcripts. Transfection studies were conducted to investigate miRNA-specific biological functions. RESULTS: Initial analysis revealed differential expression of nine miRNAs in Jurkat cells after co-culture with ionomycin. Of these, miR-524-5p and miR-449b were overexpressed in SLE T cells. Levels of expressed miR-524-5p showed a significant direct correlation with the SLEDAI. Transfection of Jurkat cells with miR-524-5p mimic suppressed Jagged-1 and Hes-1 protein expression. Likewise, expression of both Jagged-1 and Hes-1 proteins were diminished in SLE T cells. Upon activation of Jurkat cells transfected with miR-524-5p mimic, production of IFN-γ increased but the apoptotic rate was unaffected. CONCLUSION: In SLE T cells, miR-524-5p and miR-449b (both regulated by Ca(2+) influx) were overexpressed. Moreover, increased miR-524-5p expression, as shown by patients with SLE, directly paralleled disease activity (SLEDAI). Transfection of miR-524-5p also enhanced IFN-γ production in activated Jurkat cells.

Sulfasalazine Treatment Suppresses the Formation of HLA-B27 Heavy Chain Homodimer in Patients with Ankylosing Spondylitis.

Human leukocytic antigen-B27 heavy chain (HLA-B27 HC) has the tendency to fold slowly, in turn gradually forming a homodimer, (B27-HC)2 via a disulfide linkage to activate killer cells and T-helper 17 cells and inducing endoplasmic reticulum (ER) stress to trigger the IL-23/IL-17 axis for pro-inflammatory reactions. All these consequences lead to the pathogenesis of ankylosing spondylitis (AS). Sulfasalazine (SSA) is a common medication used for treatment of patients with AS. However, the effects of SSA treatment on (B27-HC)2 formation and on suppression of IL-23/IL-17 axis of AS patients remain to be determined. In the current study, we examine the (B27-HC)2 of peripheral blood mononuclear cells (PBMC), the mean grade of sarcoiliitis and lumbar spine Bath Ankylosing Spondylitis Radiology Index (BASRI) scores of 23 AS patients. The results indicated that AS patients without (B27-HC)2 on PBMC showed the lower levels of mean grade of sarcoiliitis and the lumbar spine BASRI scores. In addition, after treatment with SSA for four months, the levels of (B27-HC)2 on PBMCs were significantly reduced. Cytokines mRNA levels, including TNFα, IL-17A, IL-17F and IFNγ, were also significantly down-regulated in PBMCs. However, SSA treatment did not affect the levels of IL-23 and IL-23R mRNAs.

Characterization of the recognition specificity of BH2, a monoclonal antibody prepared against the HLA-B27 heavy chain.

BH2, a monoclonal antibody prepared against the denatured human leukocytic antigen-B27 heavy chain (HLA-B27 HC), can immunoprecipitate the misfolded HLA-B27 HC complexed with Bip in the endoplasmic reticulum and recognize the homodimerized HLA-B27 HC that is often observed on the cell membrane of patients suffered from ankylosing spondylitis (AS). However, the recognition specificity of BH2 toward the other molecules of HLA-B type and toward the different types of HLA molecules remained uncharacterized. In this study, we carried out the HLA-typing by using the Luminex Technology to characterize the recognition specificity of BH2 and analyzed the binding domain of HLA-B27 HC by BH2. Our results indicated that BH2 preferably binds to molecules of HLA-B and -C rather than HLA-A and the binding site is located within the α2 domain of HLA-B27 HC.

Anti-citrullinated protein antibodies activated ERK1/2 and JNK mitogen-activated protein kinases via binding to surface-expressed citrullinated GRP78 on mononuclear cells.

In a previous study, we found that anti-citrullinated protein antibodies (ACPAs) enhance nuclear factor (NF)-κB activity and tumor necrosis factor (TNF)-α production by normal human peripheral blood mononuclear cells (PBMCs) and U937 cells via binding to surface-expressed citrullinated glucose-regulated protein 78 (cit-GRP78). However, the downstream signaling pathways remain unclear after binding. In the present study, we firstly measured the effects of different kinase inhibitors on ACPA-mediated TNF-α production from normal PBMCs and monocytes. Then, the native and phosphorylated mitogen-activated protein kinases (MAPKs) were detected in ACPA-activated U937 cells by Western blotting. We also explored the role of the phosphoinositide 3-kinase (PI3K)-Akt pathway in activating IκB kinase alpha (IKK-α) in ACPA-stimulated U937 cells. Finally, we measured the amount of cit-GRP78 from PBMC membrane extracts in RA patients and controls. We found that MAPK and Akt inhibitors, but not PI3K inhibitor, remarkably suppressed ACPA-mediated TNF-α production. Interestingly, ACPAs selectively activated extracellular signal-regulated kinase 1/2 (ERK1/2) and c-jun N-terminal kinase (JNK), but not p38 MAPK, in U937 cells. This activation was suppressed by cit-GRP78, but not GRP78. The JNK activation further enhanced the phosphorylation of Akt and IKK-α. The expression of cit-GRP78 on cell membrane was higher in RA than normal PBMCs. Taken together; these results suggest that through binding to surface, over-expressed cit-GRP78 on RA PBMCs, ACPAs selectively activate ERK1/2 and JNK signaling pathways to enhance IKK-α phosphorylation, which leads to the activation of NF-κB and the production of TNF-α .

Renal dysfunction by BK virus infection is correlated with activated T cell level in renal transplantation.

BACKGROUND: BK virus (BKV) is known to be associated with nephropathy. Here, we investigated the relationships between BKV levels, T-cell activation, and kidney function in kidney transplant recipients. MATERIALS AND METHODS: In renal transplant patients and controls, urine BKV levels were detected by quantitative real-time PCR, and the percentage of activated T lymphocytes in blood was determined by flow cytometry. The correlations between viral load, activated T cell percentage, and renal function were determined. RESULTS: Urine BKV viral loads and the activated T cell percentage were significantly elevated in transplant recipients. Correlational analysis indicated that transplant recipients that had BKV levels of more than 10(6) copies/mL and an activated T lymphocyte percentage of less than 20% were likely to have poor renal function. CONCLUSIONS: Urine BKV levels and the percentage of activated T lymphocytes can be used as clinical indices to optimize the dosage of immunosuppressive drugs.

Anti-citrullinated protein antibodies bind surface-expressed citrullinated Grp78 on monocyte/macrophages and stimulate tumor necrosis factor alpha production.

OBJECTIVE: Anti-citrullinated protein antibodies (ACPAs), which are the most specific autoantibody marker in patients with rheumatoid arthritis (RA), correlate with disease activity; however, the role of ACPAs in RA pathogenesis has not been elucidated. We hypothesized that ACPAs may directly stimulate mononuclear cells to produce inflammatory cytokines. Thus, we identified cognate antigens of ACPAs on monocyte/macrophages and examined their immunopathologic roles in the pathogenesis of RA. METHODS: ACPAs were purified from pooled ACPA-positive RA sera by cyclic citrullinated peptide-conjugated affinity column. After coculture of U937 cells with ACPAs, the tumor necrosis factor alpha (TNFalpha) production and NF-kappaB DNA binding activity of the cells were measured by enzyme-linked immunosorbent assay. The cognate antigens of ACPAs on the U937 cell surface were probed by ACPAs, and the reactive bands were examined via proteomic analysis. RESULTS: ACPAs specifically enhanced TNFalpha production and increased the DNA-binding activity of NF-kappaB in U937 cells. Proteomic analysis revealed that Grp78 protein (72 kd) was one of the cognate antigens of ACPAs. The truncated form of cell surface-expressed Grp78 (55 kd) on U937 cells contained citrulline capable of binding with ACPAs. After citrullination, glutathione S-transferase-tagged recombinant Grp78 (97.52 kd) became a 72-kd fragment and bound with ACPAs. ACPAs also bound to human monocytes and lymphocytes to promote TNFalpha production. CONCLUSION: We clearly demonstrated that ACPAs enhance NF-kappaB activity and TNFalpha production in monocyte/macrophages via binding to surface-expressed citrullinated Grp78.

Down-Regulation of LOC645166 in T Cells of Ankylosing Spondylitis Patients Promotes the NF-κB Signaling via Decreasingly Blocking Recruitment of the IKK Complex to K63-Linked Polyubiquitin Chains.

Ankylosing spondylitis (AS) is a chronic inflammatory disease that mainly affects the spine. AS is highly associated with the expression of HLA-B27. Up to 95% AS patients are HLA-B27-positive. However, only 1%-2% of the HLA-B27-positive carriers suffer from AS, implying that other factors may also govern the development of AS. Long non-coding RNAs (lncRNAs) can regulate the immune response via their binding proteins. In the present study, we have identified that the levels of lncRNA, LOC645166, in T cells of AS patients were reduced. Overexpression of LOC645166 in Jurkat cells down-regulated the IL-23p19 expression and suppressed the JAK2/STAT3 signaling in response to stimulation by phorbol 12-myristate 13-acetate. Suppression of STAT3 activation by LOC645166 was also observed when Jurkat cells or T cells of AS patient were treated with anti-CD3/CD28 antibodies. In order to explore the role of LOC645166 in the pathogenesis of AS, RNA pull-down assay plus proteomic approach and western blotting were performed and identified that LOC645166 prefers binding the K63-linked polyubiquitin chains. LOC645166 can suppress recruitment of the IKK complex to K63-linked polyubiquitin chains and diminish IKK2 activation, leading to down-regulation of NF-κB activation. Down-regulation of LOC645166 expression in T cells of AS patients up-regulates NF-kB activation via decreasingly impeding recruitment of the IKK complex to K63-linked polyubiquitin chains, allowing AS patients to exhibit more sensitivity to stimulation by the proinflammatory cytokines or by TLR ligands.

The roles of anti-citrullinated protein antibodies in the immunopathogenesis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a common systemic autoimmune disease. Its major manifestation is persistent joint inflammation, which can lead to bone destruction and severe disability. The immunopathogenesis of RA is very complex, involving both innate and adaptive immune systems. Recently, the discovery of anti-citrullinated protein antibodies (ACPAs) has revolutionized the diagnosis and our understanding of the immunopathogenesis of RA. The presence of ACPAs is also closely linked to the disease activity of RA. Therefore, it is reasonable to believe that ACPAs and protein citrullination are key issues for the development of RA. We have summarized the recent study results in this review. The first theory concerning the pathogenesis of RA proposed that ACPAs link the well-known genetic and environmental risk factors for developing RA. However, due to the close association between joint inflammation and ACPAs, a more direct role of ACPAs in the immunopathogenesis of RA is anticipated. Within the past 10 years, many studies, including some of our own, have shown that ACPAs can promote an inflammatory response through complement activation, formation of neutrophil extracellular traps, and direct binding to key players, including monocytes, osteoclasts, and osteoblasts, in the mediation of bone destruction in the joints of RA patients. We also present some new perspectives and issues that need to be further investigated.

Increased peptidylarginine deiminases expression during the macrophage differentiation and participated inflammatory responses.

OBJECTIVE: To investigate the expression of peptidylarginine deiminases (PADIs) during macrophage differentiation and its role in inflammatory responses. METHODS: The protein expression of PADI2, PADI4, and citrullinated histone 3 in U937 cells, differentiated macrophages, and macrophages stimulated with lipopolysaccharides (LPS) were analyzed by Western blotting. Three PADI inhibitors were used for assessing their effects on the secretion of proinflammatory cytokines in macrophages. The differential expressed citrullinated proteins during macrophage differentiation were probed by self-prepared anti-citrullinated protein antibodies, and the reactive bands were sent for proteomic analyses. Transfection studies were conducted to search for the functions of specific proteins. A specific protein was cloned and citrullinated for its protein binding study. RESULTS: The expression of PADI2 and PADI4 markedly increased during macrophage differentiation, whereas the formation of citrullinated histone 3 increased after stimulated with lipopolysaccharides. Three PADI inhibitors suppressed the LPS mediated proinflammatory cytokines secretion, but did not affect the expression of PADI2 and PADI4. Plasminogen activator inhibitor-2 (PAI-2) was citrullinated during macrophage differentiation. The expression of PAI-2 increased during macrophage differentiation and further increased after stimulated with LPS. Suppressed PAI-2 expression decreased the expression and secretion of proinflammatory cytokines. Decreased PADI2 expression also suppressed the expression of PAI-2 and protein levels of citrullinated PAI-2. The citrullination of PAI-2 inhibited its binding ability to proteasome subunit beta type-1 (PSMB1). CONCLUSION: PADI2 and PADI4 protein levels increased during the macrophage differentiation resulting in protein citrullination, including PAI-2. The increased expression of PAI-2 promoted inflammatory response, and the citrullination of PAI-2 impaired its binding to PSMB1. Therefore, protein citrullination could play a critical role in macrophage differentiation and function.

Nifedipine suppresses Th1/Th2 cytokine production and increased apoptosis of anti-CD3 + anti-CD28-activated mononuclear cells from patients with systemic lupus erythematosus via calcineurin pathway.

Increased Ca(2+) influx is found in mononuclear cells (MNC) of patients with systemic lupus erythematosus (SLE). The role of calcineurin and potential implication of calcium channel blocker to suppress the abnormal Ca(2+) influx in SLE remain to be determined. In the present study, we found that the expression and phosphatase activity of calcineurin, but not calcineurin inhibitor in SLE-MNC were greater than normal MNC. Functionally, 1 microM nifedipine could suppress SLE-MNC IFN-gamma secretion but 10 microM nifedipine was required for suppressing that of normal MNC. IL-10 secretion by both SLE-MNC and normal MNC was suppressed by 1 microM nifedipine. However, high dose of nifedipine (50 microM) suppressed NFATc1 activation in SLE-MNC and enhanced apoptosis of anti-CD3 + anti-CD28-activated SLE-MNC irrelevant to expression of Fas ligand. These data suggest that SLE-MNC overexpressed calcineurin and hyper-responded to L-type Ca(2+) channel blocker-mediated apoptosis and cytokine suppression. We proposed that L-type Ca(2+) channel blocker maybe a potential medication for controlling SLE.